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• 12281. [Article] The role of body size in the foraging strategies and management of avian herbivores : a comparison of dusky Canada geese (Branta canadensis occidentalis) and cackling geese (B. hutchinsii minima) wintering in the Willamette Valley of Oregon

  Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific ...

  Citation × Citation Citation Abstract Copy Title: The role of body size in the foraging strategies and management of avian herbivores : a comparison of dusky Canada geese (Branta canadensis occidentalis) and cackling geese (B. hutchinsii minima) wintering in the Willamette Valley of Oregon Author: Mini, Anne E. Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages. In particular, avian herbivores such as geese possess a relatively simple digestive system, consume foods with low digestibility and poor nutrient content, and have increased energetic demands compared to other bird taxa; therefore, any effects of body size on foraging strategies should be readily apparent in this foraging guild. The influence of body size on the behavior and management of Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii) as avian herbivores has not been well studied. My dissertation explores the role of body size in comparative foraging behavior, habitat selection, and winter conservation planning for two congeneric geese, the Dusky Canada Goose (B. c. occidentalis; hereafter Duskys) and the Cackling Goose (B. h. minima; hereafter Cacklers). These two taxa share the same over-winter foraging environment (grass seed fields) in the same restricted geographic area (the Willamette Valley) during winter. Duskys and Cacklers differ by more than a factor of two in body size and have different relative bill sizes and social organization. Because of smaller body size, Cacklers have greater relative energy demands and less fasting endurance compared to Duskys; however, Cacklers have comparatively low energetic costs for flight and transport. Duskys, however, have higher total energy requirements than Cacklers. Additionally, Cacklers form large, high-density flocks and have a total over-wintering population size in the study area of about 200,000. Duskys occur in relatively small family groups and have a total over-wintering population size of about 13,000. My study demonstrated that interspecific differences in body size between Cacklers and Duskys was associated with differences in foraging behavior, movements, and habitat selection. Cacklers foraged a greater percentage of time (30%) in all habitats and across the entire winter compared to Duskys. Cacklers had higher peck rates (up to 100 pecks min⁻¹ greater) than Duskys in all foraging habitats expect pasture. The pecking rate of Cacklers was greatest in fields of young grass (200 pecks min⁻¹), which may indicate that Cacklers had relatively high intake rates in this foraging habitat. Based on differences in foraging behavior among habitats, Cacklers may have the foraging strategy of energy intake maximizers, whereas the foraging strategy of Duskys is more towards time-energy expenditure minimizers, at least for part of the winter. Cacklers moved across the landscape very differently from Duskys, exhibiting less site fidelity and greater commuting distances to foraging areas. Cacklers showed a preference for young grass during all periods of the winter, reaffirming that Cacklers are specialized grazers on short green forage, whereas Duskys preferred young grass and pasture. Fields of young grass were the preferred foraging habitat of Cacklers, had less standing crop biomass, and may have enabled higher foraging efficiencies, which may have led to higher intake rates. The ability of the landscape to support wintering geese changed across the winter because total available plant biomass fluctuated with the rate of grass regrowth. The estimated carrying capacity of the landscape for geese decline by almost one-half during mid-winter (mid-December to mid-February) compared to early winter or late winter periods. Although Cacklers have lower individual energy requirements compared to Duskys, due to a much larger target population size, Cacklers required 89% more foraging habitat than Duskys. Forage requirements encountered a bottleneck during mid-winter, when grass regrowth rates were low and day length was short. Commensurate with this pattern of forage availability, goose body condition declined during the mid-winter period. To support Pacific Flyway target populations for geese, approximately 18,000 ha of total grazing habitat in young and mature grass is needed in the Willamette Valley to support a total over-wintering population composed of 340,000 geese belonging to four subspecies. The role of body size in influencing the foraging behavior and decisions of over-wintering geese has important implications for conservation planning of goose populations. Small-bodied Cacklers are selective in field choice, yet more likely to redistribute across the landscape. Disturbances (e.g., hunting, hazing, or predation) will have a disproportionate effect on the movements of smaller-bodied geese compared to larger geese. These characteristics of Cacklers will make conservation planning to retain geese on public land more difficult. Coordinated management with private landowners and farming practices that maximize preferred goose foraging habitat on public lands may attract geese to utilize protected areas and minimize conflicts with agriculture in the Willamette Valley. Availability of resources during critical periods in winter is an important factor affecting the distribution of geese, but may affect small and large bodied geese differently. Management could be targeted during these critical time periods. By considering the role of body size in the context of life history characteristics, foraging behavior and habitat selection, appropriate management strategies can be developed and implemented to reduce the effects of agricultural depredation by geese, while promoting the future conservation of wintering geese in the Willamette Valley. Title: The role of body size in the foraging strategies and management of avian herbivores : a comparison of dusky Canada geese (Branta canadensis occidentalis) and cackling geese (B. hutchinsii minima) wintering in the Willamette Valley of Oregon Author: Mini, Anne E. Body size explains much of the interspecific variation in the physiology, behavior, and morphology of birds, such as metabolic rate, diet selection, intake rate, gut size, and bill size. Based on mass-specific metabolic requirements and relative energetic costs of activities, being a certain body size has both advantages and disadvantages. In particular, avian herbivores such as geese possess a relatively simple digestive system, consume foods with low digestibility and poor nutrient content, and have increased energetic demands compared to other bird taxa; therefore, any effects of body size on foraging strategies should be readily apparent in this foraging guild. The influence of body size on the behavior and management of Canada Geese (Branta canadensis) and Cackling Geese (B. hutchinsii) as avian herbivores has not been well studied. My dissertation explores the role of body size in comparative foraging behavior, habitat selection, and winter conservation planning for two congeneric geese, the Dusky Canada Goose (B. c. occidentalis; hereafter Duskys) and the Cackling Goose (B. h. minima; hereafter Cacklers). These two taxa share the same over-winter foraging environment (grass seed fields) in the same restricted geographic area (the Willamette Valley) during winter. Duskys and Cacklers differ by more than a factor of two in body size and have different relative bill sizes and social organization. Because of smaller body size, Cacklers have greater relative energy demands and less fasting endurance compared to Duskys; however, Cacklers have comparatively low energetic costs for flight and transport. Duskys, however, have higher total energy requirements than Cacklers. Additionally, Cacklers form large, high-density flocks and have a total over-wintering population size in the study area of about 200,000. Duskys occur in relatively small family groups and have a total over-wintering population size of about 13,000. My study demonstrated that interspecific differences in body size between Cacklers and Duskys was associated with differences in foraging behavior, movements, and habitat selection. Cacklers foraged a greater percentage of time (30%) in all habitats and across the entire winter compared to Duskys. Cacklers had higher peck rates (up to 100 pecks min⁻¹ greater) than Duskys in all foraging habitats expect pasture. The pecking rate of Cacklers was greatest in fields of young grass (200 pecks min⁻¹), which may indicate that Cacklers had relatively high intake rates in this foraging habitat. Based on differences in foraging behavior among habitats, Cacklers may have the foraging strategy of energy intake maximizers, whereas the foraging strategy of Duskys is more towards time-energy expenditure minimizers, at least for part of the winter. Cacklers moved across the landscape very differently from Duskys, exhibiting less site fidelity and greater commuting distances to foraging areas. Cacklers showed a preference for young grass during all periods of the winter, reaffirming that Cacklers are specialized grazers on short green forage, whereas Duskys preferred young grass and pasture. Fields of young grass were the preferred foraging habitat of Cacklers, had less standing crop biomass, and may have enabled higher foraging efficiencies, which may have led to higher intake rates. The ability of the landscape to support wintering geese changed across the winter because total available plant biomass fluctuated with the rate of grass regrowth. The estimated carrying capacity of the landscape for geese decline by almost one-half during mid-winter (mid-December to mid-February) compared to early winter or late winter periods. Although Cacklers have lower individual energy requirements compared to Duskys, due to a much larger target population size, Cacklers required 89% more foraging habitat than Duskys. Forage requirements encountered a bottleneck during mid-winter, when grass regrowth rates were low and day length was short. Commensurate with this pattern of forage availability, goose body condition declined during the mid-winter period. To support Pacific Flyway target populations for geese, approximately 18,000 ha of total grazing habitat in young and mature grass is needed in the Willamette Valley to support a total over-wintering population composed of 340,000 geese belonging to four subspecies. The role of body size in influencing the foraging behavior and decisions of over-wintering geese has important implications for conservation planning of goose populations. Small-bodied Cacklers are selective in field choice, yet more likely to redistribute across the landscape. Disturbances (e.g., hunting, hazing, or predation) will have a disproportionate effect on the movements of smaller-bodied geese compared to larger geese. These characteristics of Cacklers will make conservation planning to retain geese on public land more difficult. Coordinated management with private landowners and farming practices that maximize preferred goose foraging habitat on public lands may attract geese to utilize protected areas and minimize conflicts with agriculture in the Willamette Valley. Availability of resources during critical periods in winter is an important factor affecting the distribution of geese, but may affect small and large bodied geese differently. Management could be targeted during these critical time periods. By considering the role of body size in the context of life history characteristics, foraging behavior and habitat selection, appropriate management strategies can be developed and implemented to reduce the effects of agricultural depredation by geese, while promoting the future conservation of wintering geese in the Willamette Valley. Close

• 12282. [Article] Satisfactions and dissatisfactions of college home economics majors in retail career

  This thesis is a study of the job satisfaction Home Economics majors experience from their work in junior executive positions in retailing, an investigation of their former expectations and approach to ...

  Citation × Citation Citation Abstract Copy Title: Satisfactions and dissatisfactions of college home economics majors in retail career Author: Sampson, Sandra Smith This thesis is a study of the job satisfaction Home Economics majors experience from their work in junior executive positions in retailing, an investigation of their former expectations and approach to retailing, and an evaluation of certain specific course areas usually included in clothing, textiles, and related course areas in Home Economics curriculums. Information was obtained by surveying women currently in junior executive positions with retail firms in the western states. The satisfaction of respondents who had completed requirements for a degree in Home Economics was then compared with the satisfaction of young women who had completed requirements for a degree in any other four-year college curriculum. It became apparent from a review of the current literature on job satisfaction studies that three main categories of job satisfaction are agreed upon by many researchers. These are the satisfaction which the worker's pay and status brings him in the outside community, the satisfaction the individual receives from being employed by a certain firm and being in certain surroundings, and the intrinsic satisfactions of the actual work being done. These three categories were used as a basis to develop situations which were felt to influence job satisfaction. These situations were then used to form the job satisfaction measurement used in this study. A questionnaire was constructed to measure job satisfaction, realistic approach, and adequate preparation, and was set up in three parts. The first part of the questionnaire required the respondent to indicate demographic information, to give reasons for selecting a retail career, to evaluate major preparation, and to objectively rate her job satisfaction. The second part of the questionnaire measured preparation and realistic approach to retailing, and the third part consisted of 81 situations designed to yield a satisfaction score. Four hundred and ninety questionnaires were sent to twenty-three personnel directors in department and departmentalized speciality stores in the western states with a request that these personnel directors distribute the questionnaires to their executive trainees. Eight personnel directors indicated that they had distributed the questionnaires to their trainees and requested copies of the results of this study. Ten replied that they did not wish their trainees to cooperate in the study and 164 incompleted questionnaires were returned by them. Five personnel directors did not reply to the author's letter asking for cooperation. Of the 326 questionnaires possibly distributed to trainees, 120 were returned by young women in junior executive positions. Fifty-eight of the 120 were discarded as unusable, leaving 62 returns composed of 25 Home Economics majors and 37 non-majors. This was a 19 percent return of the total number of questionnaires which could have been received by trainees. The returned questionnaires were analyzed with the use of several statistical techniques. A mean satisfaction score for each respondent was determined on the basis of responses to the 81 situations in Part C. The Student's t-test was then used to test for differences between the average of the Home Economics majors' scores and the average of the non-majors' scores. Respondents were classified by age, length of service, age at decision of occupation, and location of college attended, and multiple range tests were used to test for differences in job satisfaction between respondents checking the various classifications. Frequency counts were made of the reasons each respondent indicated for selecting a retail career. Frequency counts were also made of each respondent's evaluation of certain clothing, textiles, and related course areas. The Student's t-test was used to test for differences in the realistic approach, as well as to determine the difference in preparation, between the two groups. The four questions designed to measure realistic approach were also analyzed independently with the use of the chi-square test for independence to determine if there was a significant difference between the realistic approach of the two groups based on the individual questions. Means for all respondents, means for Home Economics majors, and means for non-majors were determined for each of the 81 situations measuring job satisfaction to identify situations with which respondents in each of these groups were satisfied or dissatisfied. These situations were arranged in order from high satisfaction to low satisfaction for all respondents and listed in Appendix C. Also included in Appendix C are the differences between the major means and non-major, means for each of the 81 situations. The relationship between respondents' objective ratings of satisfaction and their subjective satisfaction scores are displayed in a two-way contingency table to show the distribution of frequency of occurrence of the subjective and objective measurements. The data collected from the questionnaire revealed that the mean satisfaction scores of majors and non-majors differed, and non-majors were significantly more satisfied than majors in retail junior executive training. Majors were more satisfied than non-majors with some situations and dissatisfied with others. The recommendation was made that these situations be presented to Home Economics majors planning to enter retail careers in order that they might more fully realize how these situations in their future work will affect them personally. Non-majors were also significantly more realistic than majors in, their approach to retailing. Majors felt significantly more adequately prepared than non-majors in clothing, textiles, and related course areas, but a few areas of inadequacy in Home Economics college preparation were noted for the majors. Generally, it appeared that Home Economics majors feel their college major is useful in their retail work, and a greater percentage of the majors than the non-majors would again select the same college curriculum if given the opportunity to choose again. Reasons for selecting retail careers were similar for the two groups and an interest in clothing was the reason most frequently indicated by both groups. It was concluded that Home Economics majors in this study may experience less satisfaction in retail careers than non-majors because of a lack of a realistic approach, and that future research should be conducted to determine what causes this dissatisfaction, and how it may be alleviated. Title: Satisfactions and dissatisfactions of college home economics majors in retail career Author: Sampson, Sandra Smith This thesis is a study of the job satisfaction Home Economics majors experience from their work in junior executive positions in retailing, an investigation of their former expectations and approach to retailing, and an evaluation of certain specific course areas usually included in clothing, textiles, and related course areas in Home Economics curriculums. Information was obtained by surveying women currently in junior executive positions with retail firms in the western states. The satisfaction of respondents who had completed requirements for a degree in Home Economics was then compared with the satisfaction of young women who had completed requirements for a degree in any other four-year college curriculum. It became apparent from a review of the current literature on job satisfaction studies that three main categories of job satisfaction are agreed upon by many researchers. These are the satisfaction which the worker's pay and status brings him in the outside community, the satisfaction the individual receives from being employed by a certain firm and being in certain surroundings, and the intrinsic satisfactions of the actual work being done. These three categories were used as a basis to develop situations which were felt to influence job satisfaction. These situations were then used to form the job satisfaction measurement used in this study. A questionnaire was constructed to measure job satisfaction, realistic approach, and adequate preparation, and was set up in three parts. The first part of the questionnaire required the respondent to indicate demographic information, to give reasons for selecting a retail career, to evaluate major preparation, and to objectively rate her job satisfaction. The second part of the questionnaire measured preparation and realistic approach to retailing, and the third part consisted of 81 situations designed to yield a satisfaction score. Four hundred and ninety questionnaires were sent to twenty-three personnel directors in department and departmentalized speciality stores in the western states with a request that these personnel directors distribute the questionnaires to their executive trainees. Eight personnel directors indicated that they had distributed the questionnaires to their trainees and requested copies of the results of this study. Ten replied that they did not wish their trainees to cooperate in the study and 164 incompleted questionnaires were returned by them. Five personnel directors did not reply to the author's letter asking for cooperation. Of the 326 questionnaires possibly distributed to trainees, 120 were returned by young women in junior executive positions. Fifty-eight of the 120 were discarded as unusable, leaving 62 returns composed of 25 Home Economics majors and 37 non-majors. This was a 19 percent return of the total number of questionnaires which could have been received by trainees. The returned questionnaires were analyzed with the use of several statistical techniques. A mean satisfaction score for each respondent was determined on the basis of responses to the 81 situations in Part C. The Student's t-test was then used to test for differences between the average of the Home Economics majors' scores and the average of the non-majors' scores. Respondents were classified by age, length of service, age at decision of occupation, and location of college attended, and multiple range tests were used to test for differences in job satisfaction between respondents checking the various classifications. Frequency counts were made of the reasons each respondent indicated for selecting a retail career. Frequency counts were also made of each respondent's evaluation of certain clothing, textiles, and related course areas. The Student's t-test was used to test for differences in the realistic approach, as well as to determine the difference in preparation, between the two groups. The four questions designed to measure realistic approach were also analyzed independently with the use of the chi-square test for independence to determine if there was a significant difference between the realistic approach of the two groups based on the individual questions. Means for all respondents, means for Home Economics majors, and means for non-majors were determined for each of the 81 situations measuring job satisfaction to identify situations with which respondents in each of these groups were satisfied or dissatisfied. These situations were arranged in order from high satisfaction to low satisfaction for all respondents and listed in Appendix C. Also included in Appendix C are the differences between the major means and non-major, means for each of the 81 situations. The relationship between respondents' objective ratings of satisfaction and their subjective satisfaction scores are displayed in a two-way contingency table to show the distribution of frequency of occurrence of the subjective and objective measurements. The data collected from the questionnaire revealed that the mean satisfaction scores of majors and non-majors differed, and non-majors were significantly more satisfied than majors in retail junior executive training. Majors were more satisfied than non-majors with some situations and dissatisfied with others. The recommendation was made that these situations be presented to Home Economics majors planning to enter retail careers in order that they might more fully realize how these situations in their future work will affect them personally. Non-majors were also significantly more realistic than majors in, their approach to retailing. Majors felt significantly more adequately prepared than non-majors in clothing, textiles, and related course areas, but a few areas of inadequacy in Home Economics college preparation were noted for the majors. Generally, it appeared that Home Economics majors feel their college major is useful in their retail work, and a greater percentage of the majors than the non-majors would again select the same college curriculum if given the opportunity to choose again. Reasons for selecting retail careers were similar for the two groups and an interest in clothing was the reason most frequently indicated by both groups. It was concluded that Home Economics majors in this study may experience less satisfaction in retail careers than non-majors because of a lack of a realistic approach, and that future research should be conducted to determine what causes this dissatisfaction, and how it may be alleviated. Close

• 12283. [Article] Vertebral elemental markers in elasmobranchs : potential for reconstructing environmental history and population structure

  Differences in the chemical composition of calcified structures can be used to reveal natal origins, connectivity, metapopulation structure, and reconstruct the environmental history or movement patterns ...

  Citation × Citation Citation Abstract Copy Title: Vertebral elemental markers in elasmobranchs : potential for reconstructing environmental history and population structure Author: Smith, Wade D. Differences in the chemical composition of calcified structures can be used to reveal natal origins, connectivity, metapopulation structure, and reconstruct the environmental history or movement patterns of many marine organisms. Sharks, skates, and rays (elasmobranchs) lack the calcified structures, known as otoliths, that are typically used for geochemical studies of dispersal and natal origin in fishes. If the incorporation of elements into shark and ray vertebrae is related to environmental conditions, the geochemical composition of cartilaginous vertebrae may also serve as natural tags and records of environmental history in elasmobranch populations. I used complementary laboratory and field studies to address several key assumptions regarding the incorporation of elements in elasmobranch vertebrae, providing the first detailed studies to assess relationships between water and vertebral chemical composition and the spatial and temporal variation of vertebral elemental signatures in this subclass of fishes. To validate the uptake and incorporation of elements from water to vertebrae, I conducted two laboratory studies using round stingrays, Urobatis halleri, as a model species. First, I examined the effects of temperature (16°, 18°, 24° C) on vertebral elemental incorporation (Li/Ca, Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) and found that temperature had strong, negative effects on the uptake (measured as a partition coefficient, D[subscript Element]) of magnesium and Ba and positively influenced manganese incorporation. Second, I tested the relationship between water and vertebral elemental composition by manipulating dissolved barium (Ba) concentrations (1x, 3x, 6x ambient concentrations) and found significant differences among rays from each treament. I also evaluated the influence of natural variation in somatic growth and vertebral precipitation rates on elemental incorporation. Finally, I examined the accuracy of classifying individuals to known environmental histories (temperature and barium treatments) using vertebral elemental composition. There were no significant relationships between elemental incorporation and somatic growth or vertebral precipitation rates for any elements with the exception of Zn. Relationships between somatic growth rate and D[subscript Zn] were, however, inconsistent and inconclusive. Elemental variation of vertebrae reliably distinguished U. halleri based on temperature (85%) and [Ba] (96%) history. These results support the assumption that vertebral elemental composition reflects the environmental conditions during deposition and validates the use of vertebral elemental signatures as natural markers in an elasmobranch. To evaluate the utility of vertebral geochemistry as intrinsic markers of natal origin, I collected vertebrae of young-of-the-year scalloped hammerhead sharks (Sphyrna lewini) from artisanal fishery landings at six sites along the Pacific coast of Mexico and Costa Rica between 2007-2009. A total of 386 vertebrae were used to assess patterns of spatial and temporal variation in elemental composition using laser ablation-inductively coupled plasma mass spectrometry. A protracted pupping period was confirmed for S. lewini, with newborn pups being recorded from May through mid-October. Natal elemental signatures detected in the vertebrae of the sharks varied significantly among sites and could be used to identify source populations. All element-to-calcium ratios included in these analyses (Li/Ca, Mg/Ca, V/Ca, Cr/Ca, Mn/Ca, Rb/Ca, Sr/Ca, Ba/Ca, Pb/Ca) were useful for the discerning natal origins of sharks; however, Ba, Sr, Mn, and Mg ratios most consistently generated the greatest discriminatory power based on step-wise discriminant function analyses. Classification accuracy to putative nursery areas (natal signature) and location of capture (edge signature) based on step-wise discriminant function analysis ranged from low (30-60%) to high (80-100%) depending on the degree of spatial and temporal resolution by which the data were filtered for analysis (e.g. pooled across months, early season, late season). All classification accuracies exceeded chance expectations and assignment to putative nursery areas and sites of capture were accomplished with up to 100% accuracy in several models. I found significant intra-annual differences in natal elemental signatures within the three primary study sites, which likely contributed to the low assignment accuracies when data were grouped across months of collection. Significant differences in natal elemental signatures were also detected across years. However, pair-wise analyses revealed that site-specific inter-annual variation was driven by differences associated with samples collected in 2009. Natal elemental signatures were similar between 2007 and 2009, indicating some consistency in site-specific vertebral chemistry across years. These results confirmed that vertebral elemental signatures can be applied to distinguish individuals across small (5s km), moderate (100s km), and large spatial scales (>1000 km). The potential for intra-annual variation in natal signatures within a year-class highlights the importance of cohort-specific analyses and the development of a spatial atlas of natal vertebral elemental signatures for studies of natal origin and population connectivity. The findings of my laboratory validation experiments and field study establish that geochemical analyses of vertebrae can provide reliable information on the spatial ecology and environmental history of shark and ray populations. The use of elemental signatures offers a new approach for the study and conservation of this historically vulnerable group of fishes. Title: Vertebral elemental markers in elasmobranchs : potential for reconstructing environmental history and population structure Author: Smith, Wade D. Differences in the chemical composition of calcified structures can be used to reveal natal origins, connectivity, metapopulation structure, and reconstruct the environmental history or movement patterns of many marine organisms. Sharks, skates, and rays (elasmobranchs) lack the calcified structures, known as otoliths, that are typically used for geochemical studies of dispersal and natal origin in fishes. If the incorporation of elements into shark and ray vertebrae is related to environmental conditions, the geochemical composition of cartilaginous vertebrae may also serve as natural tags and records of environmental history in elasmobranch populations. I used complementary laboratory and field studies to address several key assumptions regarding the incorporation of elements in elasmobranch vertebrae, providing the first detailed studies to assess relationships between water and vertebral chemical composition and the spatial and temporal variation of vertebral elemental signatures in this subclass of fishes. To validate the uptake and incorporation of elements from water to vertebrae, I conducted two laboratory studies using round stingrays, Urobatis halleri, as a model species. First, I examined the effects of temperature (16°, 18°, 24° C) on vertebral elemental incorporation (Li/Ca, Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) and found that temperature had strong, negative effects on the uptake (measured as a partition coefficient, D[subscript Element]) of magnesium and Ba and positively influenced manganese incorporation. Second, I tested the relationship between water and vertebral elemental composition by manipulating dissolved barium (Ba) concentrations (1x, 3x, 6x ambient concentrations) and found significant differences among rays from each treament. I also evaluated the influence of natural variation in somatic growth and vertebral precipitation rates on elemental incorporation. Finally, I examined the accuracy of classifying individuals to known environmental histories (temperature and barium treatments) using vertebral elemental composition. There were no significant relationships between elemental incorporation and somatic growth or vertebral precipitation rates for any elements with the exception of Zn. Relationships between somatic growth rate and D[subscript Zn] were, however, inconsistent and inconclusive. Elemental variation of vertebrae reliably distinguished U. halleri based on temperature (85%) and [Ba] (96%) history. These results support the assumption that vertebral elemental composition reflects the environmental conditions during deposition and validates the use of vertebral elemental signatures as natural markers in an elasmobranch. To evaluate the utility of vertebral geochemistry as intrinsic markers of natal origin, I collected vertebrae of young-of-the-year scalloped hammerhead sharks (Sphyrna lewini) from artisanal fishery landings at six sites along the Pacific coast of Mexico and Costa Rica between 2007-2009. A total of 386 vertebrae were used to assess patterns of spatial and temporal variation in elemental composition using laser ablation-inductively coupled plasma mass spectrometry. A protracted pupping period was confirmed for S. lewini, with newborn pups being recorded from May through mid-October. Natal elemental signatures detected in the vertebrae of the sharks varied significantly among sites and could be used to identify source populations. All element-to-calcium ratios included in these analyses (Li/Ca, Mg/Ca, V/Ca, Cr/Ca, Mn/Ca, Rb/Ca, Sr/Ca, Ba/Ca, Pb/Ca) were useful for the discerning natal origins of sharks; however, Ba, Sr, Mn, and Mg ratios most consistently generated the greatest discriminatory power based on step-wise discriminant function analyses. Classification accuracy to putative nursery areas (natal signature) and location of capture (edge signature) based on step-wise discriminant function analysis ranged from low (30-60%) to high (80-100%) depending on the degree of spatial and temporal resolution by which the data were filtered for analysis (e.g. pooled across months, early season, late season). All classification accuracies exceeded chance expectations and assignment to putative nursery areas and sites of capture were accomplished with up to 100% accuracy in several models. I found significant intra-annual differences in natal elemental signatures within the three primary study sites, which likely contributed to the low assignment accuracies when data were grouped across months of collection. Significant differences in natal elemental signatures were also detected across years. However, pair-wise analyses revealed that site-specific inter-annual variation was driven by differences associated with samples collected in 2009. Natal elemental signatures were similar between 2007 and 2009, indicating some consistency in site-specific vertebral chemistry across years. These results confirmed that vertebral elemental signatures can be applied to distinguish individuals across small (5s km), moderate (100s km), and large spatial scales (>1000 km). The potential for intra-annual variation in natal signatures within a year-class highlights the importance of cohort-specific analyses and the development of a spatial atlas of natal vertebral elemental signatures for studies of natal origin and population connectivity. The findings of my laboratory validation experiments and field study establish that geochemical analyses of vertebrae can provide reliable information on the spatial ecology and environmental history of shark and ray populations. The use of elemental signatures offers a new approach for the study and conservation of this historically vulnerable group of fishes. Close

• 12284. [Article] Network coding for sensor networks, distributed storage and video streaming

  The classical store-and-forward routing has and will continue to be the most important routing architecture in many modern packet-switched communication networks. In a packet-switched network, data is ...

  Citation × Citation Citation Abstract Copy Title: Network coding for sensor networks, distributed storage and video streaming Author: Nguyen, Kien Trung The classical store-and-forward routing has and will continue to be the most important routing architecture in many modern packet-switched communication networks. In a packet-switched network, data is sent in the form of discrete packets that traverse hop-by-hop from a source to a destination. At each intermediate hop, the router stores and examines the packets it receives then forwards them to the next hop until they reach the correct destinations according to some pre-defined routing algorithms. Importantly, the intermediate routers do not modify but simply store and forward the contents of the packets. In contrast, a new generalized approach to routing called Network Coding (NC) allows the intermediate routers to modify and combine packets from different sources and destinations in such a way that increases the overall throughput. The core idea of NC allowing the intermediate nodes in a network to perform data processing has a wide range of applications well beyond its initial application to routing, impacting different disciplines from distributed data storage and security to energy efficient sensor networks and Internet media streaming. To that end, this dissertation aims to develop the theories and applications of NC via four main thrusts: 1) Energy efficient NC techniques for sensor networks, 2) Novel NC techniques and protocols for Internet video streaming, 3) Stochastic data replenishment for large scale NC-based distributed storage systems, 4) Real-world implementation of NC-based distributed video streaming system. In thrust one, we describe a novel cross-sensor coding technique that combines network topology and coding techniques to maximize the life-time of a sensor network, by addressing the uneven energy consumption problem in data gathering sensor networks where the nodes closer to the sink tend to consume more energy than those of the farther nodes. Our approach is based on the following observation from the sensor networks using On-Off Keying and digital transmission: transmitting bit "1" consumes much more energy than bit "0". Our proposed coding technique exploits this difference to reduce the communication energy by limiting the number of bits "1" in the output codeword (low-weight codeword) and to use NC-based cross-sensor coding technique to equalize the communication energy among the nodes. This cross-sensor coding scheme can significantly extend the network lifetime as compared with traditional (binary) coding by solving the energy-consumption unfairness problem. The theoretical and experimental results confirm that transmission energy can be reduced substantially (e.g., a factor of 15) and the unequal energy consumption among nodes can be practically eliminated. In thrust two, we describe a rate distortion aware hierarchical NC technique and transport protocol for Internet video streaming. We begin by proposing a NC-based multi-sender streaming framework that reduces the overall storage, eliminates the complexity of sender synchronization, and enables TCP streaming. Furthermore, we propose a Hierarchical Network Coding (HNC) technique that facilitates scalable video streaming to combat bandwidth fluctuation on the Internet. This HNC technique enables receiver to recover the important data gracefully in the presence of limited bandwidth which causes an increase in decoding delay. Simulations demonstrate that under certain scenarios, our proposed NC techniques can result in bandwidth saving up to 60% over the traditional schemes. In thrust three, we present a theory of NC-based data replenishment to automate the process of data maintenance for large scale distributed storage systems. The data replenishment mechanism is the core of these systems that promises to reduce the coordination complexity and increases performance scalability. The data replenishment automates the process of maintaining a sufficient level of data redundancy to ensure the availability of data in presence of peer departures and failures. The dynamics of peers entering and leaving the network is modeled as a stochastic process. We propose a novel analytical time-backward technique to bound the expected time, the longer the better, for a piece of data to remain in P2P systems. Both theoretical and simulation results are in agreement, indicating that our proposed data replenishment via random linear network coding (RLNC) outperforms other popular strategies that employ repetition and channel coding techniques. Specifically, we show that the expected time for a piece of data to remain in a P2P system is exponential in the number of peers used to store the data for the RLNC-based strategy, while they are quadratic for other strategies. Furthermore, the time-backward technique can be applied to problems in other disciplines such as gene population modeling in theoretical biology. Finally in thrust four, we present the architecture, design, and experimental results of an actual NC-based distributed video streaming system. We first implement random linear network coding (RLNC) library and show the feasibility of using RLNC in P2P video streaming applications. Then we design, implement and analyze RESnc - a resilient P2P video storage and streaming over the Internet using network coding. RESnc increases the streaming throughput and data resiliency against peer departures and failures using peer diversity. These improvements are based on three architectural elements: 1) The RLNC scheme that breaks a video stream into multiple smaller pieces, codes, and disperses them throughout peers in the network, in such a way to maximize the probability of recovering the original video under peer departures and failures; 2) The scalable mechanism for automating the data replenishment process using RLNC to maintain a sufficient level of redundancy for video stored in the system; 3) The path-diversity streaming protocol for a client to simultaneously stream a video from multiple peers with minimal coordination. Experimental results demonstrated that our system adapts well with bandwidth fluctuation, provides significant playback quality improvement and bandwidth saving. Title: Network coding for sensor networks, distributed storage and video streaming Author: Nguyen, Kien Trung The classical store-and-forward routing has and will continue to be the most important routing architecture in many modern packet-switched communication networks. In a packet-switched network, data is sent in the form of discrete packets that traverse hop-by-hop from a source to a destination. At each intermediate hop, the router stores and examines the packets it receives then forwards them to the next hop until they reach the correct destinations according to some pre-defined routing algorithms. Importantly, the intermediate routers do not modify but simply store and forward the contents of the packets. In contrast, a new generalized approach to routing called Network Coding (NC) allows the intermediate routers to modify and combine packets from different sources and destinations in such a way that increases the overall throughput. The core idea of NC allowing the intermediate nodes in a network to perform data processing has a wide range of applications well beyond its initial application to routing, impacting different disciplines from distributed data storage and security to energy efficient sensor networks and Internet media streaming. To that end, this dissertation aims to develop the theories and applications of NC via four main thrusts: 1) Energy efficient NC techniques for sensor networks, 2) Novel NC techniques and protocols for Internet video streaming, 3) Stochastic data replenishment for large scale NC-based distributed storage systems, 4) Real-world implementation of NC-based distributed video streaming system. In thrust one, we describe a novel cross-sensor coding technique that combines network topology and coding techniques to maximize the life-time of a sensor network, by addressing the uneven energy consumption problem in data gathering sensor networks where the nodes closer to the sink tend to consume more energy than those of the farther nodes. Our approach is based on the following observation from the sensor networks using On-Off Keying and digital transmission: transmitting bit "1" consumes much more energy than bit "0". Our proposed coding technique exploits this difference to reduce the communication energy by limiting the number of bits "1" in the output codeword (low-weight codeword) and to use NC-based cross-sensor coding technique to equalize the communication energy among the nodes. This cross-sensor coding scheme can significantly extend the network lifetime as compared with traditional (binary) coding by solving the energy-consumption unfairness problem. The theoretical and experimental results confirm that transmission energy can be reduced substantially (e.g., a factor of 15) and the unequal energy consumption among nodes can be practically eliminated. In thrust two, we describe a rate distortion aware hierarchical NC technique and transport protocol for Internet video streaming. We begin by proposing a NC-based multi-sender streaming framework that reduces the overall storage, eliminates the complexity of sender synchronization, and enables TCP streaming. Furthermore, we propose a Hierarchical Network Coding (HNC) technique that facilitates scalable video streaming to combat bandwidth fluctuation on the Internet. This HNC technique enables receiver to recover the important data gracefully in the presence of limited bandwidth which causes an increase in decoding delay. Simulations demonstrate that under certain scenarios, our proposed NC techniques can result in bandwidth saving up to 60% over the traditional schemes. In thrust three, we present a theory of NC-based data replenishment to automate the process of data maintenance for large scale distributed storage systems. The data replenishment mechanism is the core of these systems that promises to reduce the coordination complexity and increases performance scalability. The data replenishment automates the process of maintaining a sufficient level of data redundancy to ensure the availability of data in presence of peer departures and failures. The dynamics of peers entering and leaving the network is modeled as a stochastic process. We propose a novel analytical time-backward technique to bound the expected time, the longer the better, for a piece of data to remain in P2P systems. Both theoretical and simulation results are in agreement, indicating that our proposed data replenishment via random linear network coding (RLNC) outperforms other popular strategies that employ repetition and channel coding techniques. Specifically, we show that the expected time for a piece of data to remain in a P2P system is exponential in the number of peers used to store the data for the RLNC-based strategy, while they are quadratic for other strategies. Furthermore, the time-backward technique can be applied to problems in other disciplines such as gene population modeling in theoretical biology. Finally in thrust four, we present the architecture, design, and experimental results of an actual NC-based distributed video streaming system. We first implement random linear network coding (RLNC) library and show the feasibility of using RLNC in P2P video streaming applications. Then we design, implement and analyze RESnc - a resilient P2P video storage and streaming over the Internet using network coding. RESnc increases the streaming throughput and data resiliency against peer departures and failures using peer diversity. These improvements are based on three architectural elements: 1) The RLNC scheme that breaks a video stream into multiple smaller pieces, codes, and disperses them throughout peers in the network, in such a way to maximize the probability of recovering the original video under peer departures and failures; 2) The scalable mechanism for automating the data replenishment process using RLNC to maintain a sufficient level of redundancy for video stored in the system; 3) The path-diversity streaming protocol for a client to simultaneously stream a video from multiple peers with minimal coordination. Experimental results demonstrated that our system adapts well with bandwidth fluctuation, provides significant playback quality improvement and bandwidth saving. Close

• 12285. [Article] Lake level regulation, shoreline erosion and shore protection : Flathead Lake, Montana

  Concern regarding increased coastal erosion has heightened amid growing acceptance of global warming and associated sea-level rise. This study examines shoreline erosion in Flathead Lake, Montana due to ...

  Citation × Citation Citation Abstract Copy Title: Lake level regulation, shoreline erosion and shore protection : Flathead Lake, Montana Author: Lorang, Mark Concern regarding increased coastal erosion has heightened amid growing acceptance of global warming and associated sea-level rise. This study examines shoreline erosion in Flathead Lake, Montana due to five decades of artificially elevated lake levels. It provides a model to investigate coastal erosion associated with sea-level rise. The natural water level fluctuation in Flathead Lake is regulated witha dam, which has elevated the entire annual fluctuation approximately 0.7 m on average. The annual rise in lake level is held for an extended duration at a regulated "full pool" level which is approximately 3 m above its natural base elevation, and the total transgression time for a complete cycle of lake level change has been increased from 100 days to over 300 days. Nearshore environments in Flathead Lake, are described as dissipative or reflective on the basis of a surf similarity parameter, grain size, morphology, number of breaking waves and angle of wave incidence. The relative resistance to foreshore and backshore erosion caused by anthropogenic lake level regulation is compared between the two nearshore configurations. Reflective systems are characterized by dynamic gravel beach faces and steep inshore shelves armored by wave-washed cobble. In contrast dissipative systems are characterized by sand-sized substratum, broad flat inshore shelves, and the presence of multiple linear bars approximately 350 m offshore. Five decades of regulated lake levels have resulted in extensive shoreline erosion (970 ha on the north shore of the lake) and a general reshaping of both types of nearshore environments, although dissipative shorelines have eroded faster. The presence of docks and other man-made structures on reflective beaches have accelerated erosion by intercepting longshore gravel transport. Shoreline erosion has ceased on the west side of the north shore as the varial zone, (that area between the maximum and minimum regulated lake levels), has reached an equilibrium slope. In contrast erosion and shoreline retreat continues on the east side, although the rate has slowed over the years in response to the development of a near equilibrium varial zone profile similar to that of the west side. However shoreline retreat is quite variable even along short stretches of shoreline. Variability in shoreline retreat results from three erosive processes, undercutting, endstripping and overwash. Undercutting and endstripping occur when waves scour an exposed bank, while overwash results when water is forced over the top of the shoreline bank or berm. Therefore shoreline elevation and morphology determine the type of erosion process, and the rate of shoreline retreat. Localized accretion also occurred due to sediment entrapment by drift logs bordering the shoreline. Drift logs naturally protect the shoreline from direct wave attack and once buried, provide new recruitment area for riparian vegetation. Alteration of lake level fluctuation has resulted in a transfer of annual wave energy from base elevations corresponding to the pre-dam nearshore shelf, to those corresponding with the limnetic foreshore environment, thereby inducing lake-wide erosion. The most extensive retreat has occurred along the low-lying dissipative north shore of the lake. Measured shoreline retreat along the north shore is compared to the retreat predicted by the Bruun Rule. The Bruun Rule under-predicted the actual measured shoreline retreat by as much as an order of magnitude. The redistribution of annual wave energy due to regulated lake level fluctuation is the main factor contributing to erosion, a factor that is not accounted for with the Bruun Rule. Therefore the redistribution of annual incident wave energy is examined in terms of an increased transgression time, a reduced range in lake level fluctuation, and an elevated lake level. Both transgression time and range in water level fluctuation affect the distribution of incident wave energy and were found to be more important to shoreline erosion than an elevated water level. An alternative regulation scheme incorporating both concerns for hydropower production and lake regulation is proposed and examined in terms of reducing erosion. Altering the transgression time of lake level fluctuation by changing the timing and increasing the rate of lake level drawdown, results in a significant reduction in the amount of annual wave energy that reaches the eroding full pool shoreline, thereby reducing the potential for shoreline erosion lake-wide. A lowered regulated full pooi lake level would decrease the intensity of overwash further reducing shoreline retreat related to that process of erosion. Natural gravel beaches can provide the backshore of coastal environments with a protective buffer from wave erosion. A case study is presented of the conceptual design and utility of an artificial perched gravel beach used to stabilize an eroding backshore on the reflective east shore of the lake. Boulders and cobbles were used as a stable platform to perch beach gravels above the previously eroding profile. A longshore exchange of gravel within the beach compartment was incorporated into the conceptual design. The structure has performed successfully during the three year monitoring period as exemplified by the lack of backshore erosion and the maintenance of the perched profile. Title: Lake level regulation, shoreline erosion and shore protection : Flathead Lake, Montana Author: Lorang, Mark Concern regarding increased coastal erosion has heightened amid growing acceptance of global warming and associated sea-level rise. This study examines shoreline erosion in Flathead Lake, Montana due to five decades of artificially elevated lake levels. It provides a model to investigate coastal erosion associated with sea-level rise. The natural water level fluctuation in Flathead Lake is regulated witha dam, which has elevated the entire annual fluctuation approximately 0.7 m on average. The annual rise in lake level is held for an extended duration at a regulated "full pool" level which is approximately 3 m above its natural base elevation, and the total transgression time for a complete cycle of lake level change has been increased from 100 days to over 300 days. Nearshore environments in Flathead Lake, are described as dissipative or reflective on the basis of a surf similarity parameter, grain size, morphology, number of breaking waves and angle of wave incidence. The relative resistance to foreshore and backshore erosion caused by anthropogenic lake level regulation is compared between the two nearshore configurations. Reflective systems are characterized by dynamic gravel beach faces and steep inshore shelves armored by wave-washed cobble. In contrast dissipative systems are characterized by sand-sized substratum, broad flat inshore shelves, and the presence of multiple linear bars approximately 350 m offshore. Five decades of regulated lake levels have resulted in extensive shoreline erosion (970 ha on the north shore of the lake) and a general reshaping of both types of nearshore environments, although dissipative shorelines have eroded faster. The presence of docks and other man-made structures on reflective beaches have accelerated erosion by intercepting longshore gravel transport. Shoreline erosion has ceased on the west side of the north shore as the varial zone, (that area between the maximum and minimum regulated lake levels), has reached an equilibrium slope. In contrast erosion and shoreline retreat continues on the east side, although the rate has slowed over the years in response to the development of a near equilibrium varial zone profile similar to that of the west side. However shoreline retreat is quite variable even along short stretches of shoreline. Variability in shoreline retreat results from three erosive processes, undercutting, endstripping and overwash. Undercutting and endstripping occur when waves scour an exposed bank, while overwash results when water is forced over the top of the shoreline bank or berm. Therefore shoreline elevation and morphology determine the type of erosion process, and the rate of shoreline retreat. Localized accretion also occurred due to sediment entrapment by drift logs bordering the shoreline. Drift logs naturally protect the shoreline from direct wave attack and once buried, provide new recruitment area for riparian vegetation. Alteration of lake level fluctuation has resulted in a transfer of annual wave energy from base elevations corresponding to the pre-dam nearshore shelf, to those corresponding with the limnetic foreshore environment, thereby inducing lake-wide erosion. The most extensive retreat has occurred along the low-lying dissipative north shore of the lake. Measured shoreline retreat along the north shore is compared to the retreat predicted by the Bruun Rule. The Bruun Rule under-predicted the actual measured shoreline retreat by as much as an order of magnitude. The redistribution of annual wave energy due to regulated lake level fluctuation is the main factor contributing to erosion, a factor that is not accounted for with the Bruun Rule. Therefore the redistribution of annual incident wave energy is examined in terms of an increased transgression time, a reduced range in lake level fluctuation, and an elevated lake level. Both transgression time and range in water level fluctuation affect the distribution of incident wave energy and were found to be more important to shoreline erosion than an elevated water level. An alternative regulation scheme incorporating both concerns for hydropower production and lake regulation is proposed and examined in terms of reducing erosion. Altering the transgression time of lake level fluctuation by changing the timing and increasing the rate of lake level drawdown, results in a significant reduction in the amount of annual wave energy that reaches the eroding full pool shoreline, thereby reducing the potential for shoreline erosion lake-wide. A lowered regulated full pooi lake level would decrease the intensity of overwash further reducing shoreline retreat related to that process of erosion. Natural gravel beaches can provide the backshore of coastal environments with a protective buffer from wave erosion. A case study is presented of the conceptual design and utility of an artificial perched gravel beach used to stabilize an eroding backshore on the reflective east shore of the lake. Boulders and cobbles were used as a stable platform to perch beach gravels above the previously eroding profile. A longshore exchange of gravel within the beach compartment was incorporated into the conceptual design. The structure has performed successfully during the three year monitoring period as exemplified by the lack of backshore erosion and the maintenance of the perched profile. Close

• 12286. [Article] Wildlife Health in Managed Forests : Immunity and Infectious Diseases in Wild Rodents of Oregon

  With continual and worldwide human population growth, our impact on the natural environment expands and intensifies every day. We consume natural resources, burn fossil fuels, and release toxic compounds ...

  Citation × Citation Citation Abstract Copy Title: Wildlife Health in Managed Forests : Immunity and Infectious Diseases in Wild Rodents of Oregon Author: Hanselmann, Rhea With continual and worldwide human population growth, our impact on the natural environment expands and intensifies every day. We consume natural resources, burn fossil fuels, and release toxic compounds into the air, water, and earth. We build roads that fragment the landscape, construct new settlements, and develop agricultural lands in previously undisturbed areas. And, we introduce non-native species, which compete with and/or prey on native ones. Our actions change the composition of ecosystems by effacing natural environments and decimating plant and animal populations. We have reached a time of unprecedented anthropogenic environmental change. And, while we recognize, and work feverishly to mitigate, countless consequences of our actions, we still lack a profound understanding of just as many of the corollaries of the environmental changes we provoke. One thing we do know is that human-induced changes in environmental conditions can affect health – from individual organisms, to plant and animal populations, all the way to the level of the ecosystem. Yet, the mechanisms underlying such adverse health outcomes are only partially understood. For instance, we know that alterations in the structure of plant and animal communities, the distribution and demographics of populations, and the abundance of individuals can influence the emergence or re-emergence of infectious diseases. Which species are present in a community, where, when, and in what numbers can all determine the dynamics of pathogens, lead to disease outbreaks, and provide opportunities for spillover into new species. However, given the many environmental-, population-, and organism-level factors involved, and the complexity by which these variables interact, detecting and predicting the ultimate consequences for the health of animal, including human, populations remains difficult. Wild animals play important roles in numerous infectious disease cycles, many of which are shared with humans. Considering this and the well-documented effects that human activity can have on wildlife populations, studying the impacts of anthropogenic environmental change on health in wildlife is highly relevant. To understand how human-induced environmental changes affect wildlife health and to make predictions about potential regional or even global consequences for the dynamics of infectious diseases, however, we first need to understand patterns at a local scale. Here, I describe variation in immune function in captive and wild rodent species native to managed forests in northwestern Oregon, and examine how intensive forest management practices affect these and other physiological processes, and the prevalence of infectious diseases, in a large-scale field experiment. In Chapter 2 of this dissertation, I present baseline data on simple immune parameters in an iconic inhabitant of old-growth forests in the Pacific Northwest, the red tree vole (Arborimus longicaudus). I show that both body condition and age are important for immune defenses in this species. Translating these findings to wild populations leads me to predict that degradation of habitat may affect red tree voles not only at the population scale, as is currently the case, but that less obvious consequences for the health of individuals surviving in disturbed or suboptimal habitat are also possible. It is important, therefore, that efforts to conserve this species consider adverse effects of present forest management practices on red tree vole health, as potentially increased disease susceptibility could have detrimental outcomes for this species. In Chapters 3 and 4, I took advantage of a rare and large-scale experiment to test my predictions regarding the negative consequences of habitat degradation for individual animals in more ubiquitous rodent species known for their resilience to environmental disturbance. I investigated the effects of intensive forest management on stress, health, and immunity (Chapter 3), and on the prevalence of infectious diseases transmissible to humans (Chapter 4) in deer mice (Peromyscus maniculatus), Townsend chipmunks (Tamias townsendii), and creeping voles (Microtus oregoni) inhabiting managed forest plots in northwestern Oregon. The experimental design employed allowed me to test the effect of regionally representative forest management practices on health and disease outcomes with important implications for public health. In Chapter 3, I present results which suggest that intensive forest management can have complex, but highly context-dependent effects on the health of wild deer mice. Intensive forest management can shape animals’ condition and reproductive activity, increase levels of stress hormone, and stimulate some but depress other immune responses. However, deer mice are only able to respond to the extreme stressor of this disturbance when underlying environmental conditions are favorable. When inhabiting inherently harsh habitat, mice appear unable to cope with additional disturbance imposed by intensive forest management, and only the fittest mice survive. Finally, in Chapter 4, I identify moderate prevalence of two important and potentially fatal human infections in rodents inhabiting managed forests in northwestern Oregon. In deer mouse populations, Sin Nombre virus was clustered spatially, and prevalence varied between years. But, in the focus of highest infection, the proportion of infected mice, albeit low, appeared to increase with intensity of forest management. For Leptospirosis, I found a similar pattern in creeping voles, but did not observe an association between infection prevalence and forest management in deer mice or chipmunks. I conclude that forest management may drive infectious disease patterns, but that the direction and magnitude of such effects depends on the host-pathogen system. Taken together, my findings indicate that wild animal health can suffer from declines in habitat quality associated with forest management. For a near-threatened species such as the red tree vole, decreases in the availability of food and nesting habitat have the potential to change susceptibility to infection, which could facilitate disease invasion and further threaten populations. For wild animals that serve as reservoirs for human infections, especially abundant and apparently resilient species, impaired health can drive the dynamics of pathogens and increase the risk of transmission to humans and other animals. Although many more questions remain, my work contributes to our understanding of the effects of anthropogenic environmental change for wildlife and human health. Title: Wildlife Health in Managed Forests : Immunity and Infectious Diseases in Wild Rodents of Oregon Author: Hanselmann, Rhea With continual and worldwide human population growth, our impact on the natural environment expands and intensifies every day. We consume natural resources, burn fossil fuels, and release toxic compounds into the air, water, and earth. We build roads that fragment the landscape, construct new settlements, and develop agricultural lands in previously undisturbed areas. And, we introduce non-native species, which compete with and/or prey on native ones. Our actions change the composition of ecosystems by effacing natural environments and decimating plant and animal populations. We have reached a time of unprecedented anthropogenic environmental change. And, while we recognize, and work feverishly to mitigate, countless consequences of our actions, we still lack a profound understanding of just as many of the corollaries of the environmental changes we provoke. One thing we do know is that human-induced changes in environmental conditions can affect health – from individual organisms, to plant and animal populations, all the way to the level of the ecosystem. Yet, the mechanisms underlying such adverse health outcomes are only partially understood. For instance, we know that alterations in the structure of plant and animal communities, the distribution and demographics of populations, and the abundance of individuals can influence the emergence or re-emergence of infectious diseases. Which species are present in a community, where, when, and in what numbers can all determine the dynamics of pathogens, lead to disease outbreaks, and provide opportunities for spillover into new species. However, given the many environmental-, population-, and organism-level factors involved, and the complexity by which these variables interact, detecting and predicting the ultimate consequences for the health of animal, including human, populations remains difficult. Wild animals play important roles in numerous infectious disease cycles, many of which are shared with humans. Considering this and the well-documented effects that human activity can have on wildlife populations, studying the impacts of anthropogenic environmental change on health in wildlife is highly relevant. To understand how human-induced environmental changes affect wildlife health and to make predictions about potential regional or even global consequences for the dynamics of infectious diseases, however, we first need to understand patterns at a local scale. Here, I describe variation in immune function in captive and wild rodent species native to managed forests in northwestern Oregon, and examine how intensive forest management practices affect these and other physiological processes, and the prevalence of infectious diseases, in a large-scale field experiment. In Chapter 2 of this dissertation, I present baseline data on simple immune parameters in an iconic inhabitant of old-growth forests in the Pacific Northwest, the red tree vole (Arborimus longicaudus). I show that both body condition and age are important for immune defenses in this species. Translating these findings to wild populations leads me to predict that degradation of habitat may affect red tree voles not only at the population scale, as is currently the case, but that less obvious consequences for the health of individuals surviving in disturbed or suboptimal habitat are also possible. It is important, therefore, that efforts to conserve this species consider adverse effects of present forest management practices on red tree vole health, as potentially increased disease susceptibility could have detrimental outcomes for this species. In Chapters 3 and 4, I took advantage of a rare and large-scale experiment to test my predictions regarding the negative consequences of habitat degradation for individual animals in more ubiquitous rodent species known for their resilience to environmental disturbance. I investigated the effects of intensive forest management on stress, health, and immunity (Chapter 3), and on the prevalence of infectious diseases transmissible to humans (Chapter 4) in deer mice (Peromyscus maniculatus), Townsend chipmunks (Tamias townsendii), and creeping voles (Microtus oregoni) inhabiting managed forest plots in northwestern Oregon. The experimental design employed allowed me to test the effect of regionally representative forest management practices on health and disease outcomes with important implications for public health. In Chapter 3, I present results which suggest that intensive forest management can have complex, but highly context-dependent effects on the health of wild deer mice. Intensive forest management can shape animals’ condition and reproductive activity, increase levels of stress hormone, and stimulate some but depress other immune responses. However, deer mice are only able to respond to the extreme stressor of this disturbance when underlying environmental conditions are favorable. When inhabiting inherently harsh habitat, mice appear unable to cope with additional disturbance imposed by intensive forest management, and only the fittest mice survive. Finally, in Chapter 4, I identify moderate prevalence of two important and potentially fatal human infections in rodents inhabiting managed forests in northwestern Oregon. In deer mouse populations, Sin Nombre virus was clustered spatially, and prevalence varied between years. But, in the focus of highest infection, the proportion of infected mice, albeit low, appeared to increase with intensity of forest management. For Leptospirosis, I found a similar pattern in creeping voles, but did not observe an association between infection prevalence and forest management in deer mice or chipmunks. I conclude that forest management may drive infectious disease patterns, but that the direction and magnitude of such effects depends on the host-pathogen system. Taken together, my findings indicate that wild animal health can suffer from declines in habitat quality associated with forest management. For a near-threatened species such as the red tree vole, decreases in the availability of food and nesting habitat have the potential to change susceptibility to infection, which could facilitate disease invasion and further threaten populations. For wild animals that serve as reservoirs for human infections, especially abundant and apparently resilient species, impaired health can drive the dynamics of pathogens and increase the risk of transmission to humans and other animals. Although many more questions remain, my work contributes to our understanding of the effects of anthropogenic environmental change for wildlife and human health. Close

• 12287. [Article] Distribution, Abundance, and Settlement of Slope-spawning Flatfish during Early Life Stages in the Eastern Bering Sea

  Changes in environmental conditions in marine ecosystems could directly or indirectly influence distribution, abundance, settlement, and size at settlement of flatfish. Understanding species-specific and ...

  Citation × Citation Citation Abstract Copy Title: Distribution, Abundance, and Settlement of Slope-spawning Flatfish during Early Life Stages in the Eastern Bering Sea Author: Sohn, Dongwha Changes in environmental conditions in marine ecosystems could directly or indirectly influence distribution, abundance, settlement, and size at settlement of flatfish. Understanding species-specific and age-specific responses to environmental variability is important for managing commercially important flatfish stocks. Slope-spawning flatfish whose offspring rely on extensive drift from the slope (spawning) to the shelf (settlement) and which require specific habitat for settlement could be especially vulnerable to environmental variability. Arrowtooth flounder (ATF; Atheresthes stomias), Greenland halibut (GH; Reinhardtius hippoglossoides), and Pacific halibut (PH; Hippoglossus stenolepis) are commercially and ecologically important slope-spawning flatfish species in the eastern Bering Sea (EBS), which has experienced fluctuating warm and cold periods since 2000. Although the three species share many attributes, their population trajectories have fluctuated differently. This difference could result from contrasting responses to environmental variability during early life history. To understand how physical variability of the Bering Sea can differentially affect flatfish ecology from pre-settlement to post-settlement phases, I used a combination of field data, biophysical modeling, and statistical modeling to characterize early life stage attributes (chapter 2), settlement success (chapter 3), and size, abundance, and distribution at settlement (age-0) and age-1 (chapter 4). Based on historical ichthyoplankton survey data for GH and PH, I found that there were species-specific differences in the spatial distribution (vertically and horizontally) and juvenile nursery areas between the two species during early life stages in the EBS. Specifically, I found that PH larvae abruptly move to shallower water as they grow, and cross onto the shelf earlier than GH. This ontogenetic movement has the benefit of allowing PH larvae to take advantage of on-shelf transport to reach their settlement locations. However, an early transition from the slope to the shelf may not equally benefit GH, whose settlement locations are further from the spawning ground. Using a bio-physical modeling approach parameterized on the field data summarized in chapter 2, I found that species-specific variability of early life attributes causes interannual and species-specific variability of GH and PH settlement success in the EBS. GH settlement increased with increasing along-shelf (northwestward) flow whereas PH settlement decreased. GH that spawned in November and December were highly successful at settling while PH settlement was most successful when they spawned in January and February. Furthermore, GH settlement is affected by temperature dependence of pelagic larval duration, but not PH, indicating a strong resilience of PH to temperature induced variations in development and dispersal duration. Using otolith microstructure analysis, I found that variations in size at settlement for ATF are significantly correlated with latitude of sampling location. For GH, their size at settlement is associated with bottom water temperature and sea ice extent. Especially, sea ice coverage has a strong negative correlation with on-shelf winds, which drive along-shelf Ekman transport to southeast impacting dispersal pathways and duration. Size at settlement for ATF increased with increasing latitude of sampling location, which could be impacted by currents. For GH, size at settlement decreased with decreasing bottom water temperature and increasing sea ice extent. Also, my results showed that settlement habitat increases for GH in cold years whereas that of ATF increases in warm years. The bottom temperature of age-0 habitat for both ATF and GH affected on their age-1 abundance; GH age-1 abundance increased with decreasing bottom temperature of age-0 habitat, but no clear directionality was found for ATF. The findings from this study have implications for understanding settlement success and recruitment of slope-spawning flatfish in the EBS. In most cold years when along-shelf flow is generally strong, the level of larval supply of GH to their settlement areas is higher than in warm years. Size at settlement for GH decreased in cold years. The larger amount of suitable habitat for settlement and post-settlement stages could result in lower competition and less predation in comparison to warm years. In support of this hypothesis, I found greater age-1 abundance in cold years, indicating size at settlement in GH may not be critical compared to suitability of habitat features and larval supply to settlement grounds. On the other hand, in cold years with strong along-shelf transport to northwest, PH (or ATF), which settle in the southern part of the EBS, have lower numbers of successful settlers. Size at settlement for ATF increased in cold years, and I assumed that size at settlement for PH may have similar patterns. The amount of suitable habitat after settlement would be smaller, resulting in lower recruitment due to increased competition for limited resources. By studying how physical factors and their variability influence these three flatfish during early life stages, this study provides valuable insight into the response of flatfish stocks to past and future climate changes in the eastern Bering Sea – a system that is especially vulnerable to warming. Title: Distribution, Abundance, and Settlement of Slope-spawning Flatfish during Early Life Stages in the Eastern Bering Sea Author: Sohn, Dongwha Changes in environmental conditions in marine ecosystems could directly or indirectly influence distribution, abundance, settlement, and size at settlement of flatfish. Understanding species-specific and age-specific responses to environmental variability is important for managing commercially important flatfish stocks. Slope-spawning flatfish whose offspring rely on extensive drift from the slope (spawning) to the shelf (settlement) and which require specific habitat for settlement could be especially vulnerable to environmental variability. Arrowtooth flounder (ATF; Atheresthes stomias), Greenland halibut (GH; Reinhardtius hippoglossoides), and Pacific halibut (PH; Hippoglossus stenolepis) are commercially and ecologically important slope-spawning flatfish species in the eastern Bering Sea (EBS), which has experienced fluctuating warm and cold periods since 2000. Although the three species share many attributes, their population trajectories have fluctuated differently. This difference could result from contrasting responses to environmental variability during early life history. To understand how physical variability of the Bering Sea can differentially affect flatfish ecology from pre-settlement to post-settlement phases, I used a combination of field data, biophysical modeling, and statistical modeling to characterize early life stage attributes (chapter 2), settlement success (chapter 3), and size, abundance, and distribution at settlement (age-0) and age-1 (chapter 4). Based on historical ichthyoplankton survey data for GH and PH, I found that there were species-specific differences in the spatial distribution (vertically and horizontally) and juvenile nursery areas between the two species during early life stages in the EBS. Specifically, I found that PH larvae abruptly move to shallower water as they grow, and cross onto the shelf earlier than GH. This ontogenetic movement has the benefit of allowing PH larvae to take advantage of on-shelf transport to reach their settlement locations. However, an early transition from the slope to the shelf may not equally benefit GH, whose settlement locations are further from the spawning ground. Using a bio-physical modeling approach parameterized on the field data summarized in chapter 2, I found that species-specific variability of early life attributes causes interannual and species-specific variability of GH and PH settlement success in the EBS. GH settlement increased with increasing along-shelf (northwestward) flow whereas PH settlement decreased. GH that spawned in November and December were highly successful at settling while PH settlement was most successful when they spawned in January and February. Furthermore, GH settlement is affected by temperature dependence of pelagic larval duration, but not PH, indicating a strong resilience of PH to temperature induced variations in development and dispersal duration. Using otolith microstructure analysis, I found that variations in size at settlement for ATF are significantly correlated with latitude of sampling location. For GH, their size at settlement is associated with bottom water temperature and sea ice extent. Especially, sea ice coverage has a strong negative correlation with on-shelf winds, which drive along-shelf Ekman transport to southeast impacting dispersal pathways and duration. Size at settlement for ATF increased with increasing latitude of sampling location, which could be impacted by currents. For GH, size at settlement decreased with decreasing bottom water temperature and increasing sea ice extent. Also, my results showed that settlement habitat increases for GH in cold years whereas that of ATF increases in warm years. The bottom temperature of age-0 habitat for both ATF and GH affected on their age-1 abundance; GH age-1 abundance increased with decreasing bottom temperature of age-0 habitat, but no clear directionality was found for ATF. The findings from this study have implications for understanding settlement success and recruitment of slope-spawning flatfish in the EBS. In most cold years when along-shelf flow is generally strong, the level of larval supply of GH to their settlement areas is higher than in warm years. Size at settlement for GH decreased in cold years. The larger amount of suitable habitat for settlement and post-settlement stages could result in lower competition and less predation in comparison to warm years. In support of this hypothesis, I found greater age-1 abundance in cold years, indicating size at settlement in GH may not be critical compared to suitability of habitat features and larval supply to settlement grounds. On the other hand, in cold years with strong along-shelf transport to northwest, PH (or ATF), which settle in the southern part of the EBS, have lower numbers of successful settlers. Size at settlement for ATF increased in cold years, and I assumed that size at settlement for PH may have similar patterns. The amount of suitable habitat after settlement would be smaller, resulting in lower recruitment due to increased competition for limited resources. By studying how physical factors and their variability influence these three flatfish during early life stages, this study provides valuable insight into the response of flatfish stocks to past and future climate changes in the eastern Bering Sea – a system that is especially vulnerable to warming. Close

• 12288. [Article] Potentiation of acute carbon tetrachloride hepatotoxicity by dietary exposure to chlorophenothane (DDT) in rats

  There has been no toxicologic proof that the long-term, low-level exposure of man to chlorophenothane (DDT) is linked with an increased susceptibility to toxicity or disease. Acute pretreatment of rats ...

  Citation × Citation Citation Abstract Copy Title: Potentiation of acute carbon tetrachloride hepatotoxicity by dietary exposure to chlorophenothane (DDT) in rats Author: Koeferl, Michael Tallyn There has been no toxicologic proof that the long-term, low-level exposure of man to chlorophenothane (DDT) is linked with an increased susceptibility to toxicity or disease. Acute pretreatment of rats with 75-100 mg/kg DDT has been demonstrated to potentiate CCI₄-induced hepatotoxicity in that species (McLean and McLean, 1966). Since the hepatotoxic response to CC1₄ is similar among mammalian species, it was believed man's response could also be altered by prior exposure to DDT. Chronic pretreatment of rats with DDT more closely duplicates man's exposure situation, which is mainly dietary. Therefore, this present investigation was undertaken to quantify the DDT-CCI₄ hepatotoxic interaction in rats from the standpoint of a chronic dietary exposure to DDT. Chronic and acute pretreatments with DDT were compared for their relative effects on acute CC1₄ hepatotoxicity. Subgroups of rats fed DDT at concentrations of 6-65 ppm for three weeks and 65 ppm for 24 weeks attained body burdens of DDT and its metabolites ranging from 6.1 to 30.6 ppm, compared to 0 ppm (no detectable) for controls. In the acute study, subgroups of rats were dosed with 35-150 mg/kg DDT by gavage 24 hours prior to CC1₄ exposure. Doses of CC1₄ ranging from 0.125 to 1.0 mi./kg were administered by gavage. All pretreatments with DDT, chronic or acute, resulted in a potentiated elevation of serum transaminase (SGPT and SGOT) activities following treatment with CC1₄. The degree of potentiation was dose-related to CCI₄ and to the total DDT body burden. In a temporal study, the onset of the potentiated response was noted six hours after CC1₄. All of the above-mentioned results were confirmed by histopathology. Plasma BSP disappearance, dose-response and temporal studies were conducted in control and DDT-fed rat groups, utilizing the BSP test as an index of hepatic functional impairment, CC1₄-induced BSP retention was greatly potentiated by prior dietary exposure to DDT. This potentiation effect was obscured at a dose of 2.0 ml/kg CC1₄, due to the severe hepatic damage produced by this dose of CCI₄ given alone. The onset and development of the potentiated hepatic dysfunction paralleled that of the parenchymal cell destruction. The potentiated CC1₄-induced increases in SGOT activity and centrilobularly-oriented coagulative necrosis in the DDT-fed animals were prevented by spinal cord transection at the level of the seventh cervical vertebra. Chronic DDT pretreatment did not enhance CC1₄ uptake into the blood or livers of intact rats, and this was ruled out as a possible mechanism for the potentiation effect. Cord-sectioning did enhance tissue CC1₄ uptake, yet these animals were protected against CC1₄-induced central necrosis. Neither cord-sectioning nor the resultant hypothermia reduced the microsomal cytochrome P-450 content in control or DDT-fed rats. Hypothermia depressed the in vitro N-demethylation of ethylmorphine, so that oxidative drug metabolism was probably also decreased in vivo in the cordotomized animals. Maximal blood and liver concentrations of CC1₄ were measured between 2-4 hours in the intact control and DDT-fed groups. These tissue CC1₄ concentrations decreased more rapidly between 4-12 hours in the DDT-fed rats, thus suggesting an increased rate of CC1₄ metabolism could have occurred at this time in vivo in these animals. Unlike the other indices of hepatic damage, the cytochrome P-450 response preceded rather than followed the hepatocellular destruction. About 75% of the induced cytochrome P-450 concentration in the DDTfed rats was destroyed within six hours after CC1₄, at which time the onset of potentiated hepatic damage was detected. In the controls, the cytochrome P-450 concentration regenerated from a low value at 18 hours to normal by 48 hours after CC1₄. Hepatic regeneration was impaired in the DDT-fed rats, since the cytochrome P-450 concentration continued to decline between 24-48 hours. The amount of cytochrome P-450 destruction appeared to correlate with the degree of hepatic damage observed. Lower absolute concentrations of cytochrome P-450 were measured in controls 24 hours after dosing with 0.125-2.0 ml/kg CC1₄. More cytochrome P-450 was destroyed in the DDT-fed group, however, as a result of the induced microsomal concentrations of this cytochrome present initially before CC1₄ was given. Thus, the CCI₄- cytochrome P-450 interaction could play an integral role in the potentiation phenomenon, as McLean and McLean (1969) have suggested. Liver weight increased in a dose-related manner to CC1₄ in both control and DDT-fed groups, but the response was greater in controls. In the control animals, the liver weight increased rapidly to a maximal value at 18 hours, but returned to normal by 48 hours after CC1₄. Although the onset of the response was slower in the DDT-fed rats, the liver weight continued to increase at 48 hours. Rectal temperatures declined between 6-24 hours only in the DDT-fed animals. The pharmacologic agents SKF 525-A (drug metabolism inhibitor) and lead (porphyrin biosynthesis inhibitor) were utilized to assess the role of cytochrome P-450 in potentiation. SKF 525-A provided protection against the potentiated CC1₄-induced centrilobular necrosis at 11 hours after CC1₄. This protection could not be positively ascribed to SKF 525-A binding with cytochrome P-450 or inhibiting CC1₄ metabolism, since SKF 525-A has been reported to alter the gastrointestinal absorption of CC1₄ (Marchand, McLean and Plaa, 1970). Lead significantly reduced the effect of prior DDT feeding in potentiating CC1₄ hepatotoxicity, but this protection did not result from a lowered microsomal cytochrome P-450 content. Thus, the role of cytochrome P-450 in the potentiation effect remains to be conclusively elucidated. Mecamylamine pretreatment was used to determine the importance of the sympathomimetic properties of DDT in potentiation. This ganglionic blocking agent produced an insignificant tendency to decrease the potentiated CC1₄- induced BSP retention. However, the histologic evidence of protection against CC1₄ -induced hepatic necrosis was not apparent in mecamylamine-pretreated animals. Thus, the central sympathetic nervous system stimulatory effects of DDT are probably not directly involved in potentiation. The basis for extrapolation of these results from rat to man could be the total DDT body burden, which was similar in these rats (6.1 -30.6 ppm) to that estimated for man, e.g., 10 ppm by Durham (1965). Since rats and man respond similarly to CC1₄, these results indicate that man's chronic exposure to DDT could render him highly susceptible to a secondary exposure to CC1₄. Title: Potentiation of acute carbon tetrachloride hepatotoxicity by dietary exposure to chlorophenothane (DDT) in rats Author: Koeferl, Michael Tallyn There has been no toxicologic proof that the long-term, low-level exposure of man to chlorophenothane (DDT) is linked with an increased susceptibility to toxicity or disease. Acute pretreatment of rats with 75-100 mg/kg DDT has been demonstrated to potentiate CCI₄-induced hepatotoxicity in that species (McLean and McLean, 1966). Since the hepatotoxic response to CC1₄ is similar among mammalian species, it was believed man's response could also be altered by prior exposure to DDT. Chronic pretreatment of rats with DDT more closely duplicates man's exposure situation, which is mainly dietary. Therefore, this present investigation was undertaken to quantify the DDT-CCI₄ hepatotoxic interaction in rats from the standpoint of a chronic dietary exposure to DDT. Chronic and acute pretreatments with DDT were compared for their relative effects on acute CC1₄ hepatotoxicity. Subgroups of rats fed DDT at concentrations of 6-65 ppm for three weeks and 65 ppm for 24 weeks attained body burdens of DDT and its metabolites ranging from 6.1 to 30.6 ppm, compared to 0 ppm (no detectable) for controls. In the acute study, subgroups of rats were dosed with 35-150 mg/kg DDT by gavage 24 hours prior to CC1₄ exposure. Doses of CC1₄ ranging from 0.125 to 1.0 mi./kg were administered by gavage. All pretreatments with DDT, chronic or acute, resulted in a potentiated elevation of serum transaminase (SGPT and SGOT) activities following treatment with CC1₄. The degree of potentiation was dose-related to CCI₄ and to the total DDT body burden. In a temporal study, the onset of the potentiated response was noted six hours after CC1₄. All of the above-mentioned results were confirmed by histopathology. Plasma BSP disappearance, dose-response and temporal studies were conducted in control and DDT-fed rat groups, utilizing the BSP test as an index of hepatic functional impairment, CC1₄-induced BSP retention was greatly potentiated by prior dietary exposure to DDT. This potentiation effect was obscured at a dose of 2.0 ml/kg CC1₄, due to the severe hepatic damage produced by this dose of CCI₄ given alone. The onset and development of the potentiated hepatic dysfunction paralleled that of the parenchymal cell destruction. The potentiated CC1₄-induced increases in SGOT activity and centrilobularly-oriented coagulative necrosis in the DDT-fed animals were prevented by spinal cord transection at the level of the seventh cervical vertebra. Chronic DDT pretreatment did not enhance CC1₄ uptake into the blood or livers of intact rats, and this was ruled out as a possible mechanism for the potentiation effect. Cord-sectioning did enhance tissue CC1₄ uptake, yet these animals were protected against CC1₄-induced central necrosis. Neither cord-sectioning nor the resultant hypothermia reduced the microsomal cytochrome P-450 content in control or DDT-fed rats. Hypothermia depressed the in vitro N-demethylation of ethylmorphine, so that oxidative drug metabolism was probably also decreased in vivo in the cordotomized animals. Maximal blood and liver concentrations of CC1₄ were measured between 2-4 hours in the intact control and DDT-fed groups. These tissue CC1₄ concentrations decreased more rapidly between 4-12 hours in the DDT-fed rats, thus suggesting an increased rate of CC1₄ metabolism could have occurred at this time in vivo in these animals. Unlike the other indices of hepatic damage, the cytochrome P-450 response preceded rather than followed the hepatocellular destruction. About 75% of the induced cytochrome P-450 concentration in the DDTfed rats was destroyed within six hours after CC1₄, at which time the onset of potentiated hepatic damage was detected. In the controls, the cytochrome P-450 concentration regenerated from a low value at 18 hours to normal by 48 hours after CC1₄. Hepatic regeneration was impaired in the DDT-fed rats, since the cytochrome P-450 concentration continued to decline between 24-48 hours. The amount of cytochrome P-450 destruction appeared to correlate with the degree of hepatic damage observed. Lower absolute concentrations of cytochrome P-450 were measured in controls 24 hours after dosing with 0.125-2.0 ml/kg CC1₄. More cytochrome P-450 was destroyed in the DDT-fed group, however, as a result of the induced microsomal concentrations of this cytochrome present initially before CC1₄ was given. Thus, the CCI₄- cytochrome P-450 interaction could play an integral role in the potentiation phenomenon, as McLean and McLean (1969) have suggested. Liver weight increased in a dose-related manner to CC1₄ in both control and DDT-fed groups, but the response was greater in controls. In the control animals, the liver weight increased rapidly to a maximal value at 18 hours, but returned to normal by 48 hours after CC1₄. Although the onset of the response was slower in the DDT-fed rats, the liver weight continued to increase at 48 hours. Rectal temperatures declined between 6-24 hours only in the DDT-fed animals. The pharmacologic agents SKF 525-A (drug metabolism inhibitor) and lead (porphyrin biosynthesis inhibitor) were utilized to assess the role of cytochrome P-450 in potentiation. SKF 525-A provided protection against the potentiated CC1₄-induced centrilobular necrosis at 11 hours after CC1₄. This protection could not be positively ascribed to SKF 525-A binding with cytochrome P-450 or inhibiting CC1₄ metabolism, since SKF 525-A has been reported to alter the gastrointestinal absorption of CC1₄ (Marchand, McLean and Plaa, 1970). Lead significantly reduced the effect of prior DDT feeding in potentiating CC1₄ hepatotoxicity, but this protection did not result from a lowered microsomal cytochrome P-450 content. Thus, the role of cytochrome P-450 in the potentiation effect remains to be conclusively elucidated. Mecamylamine pretreatment was used to determine the importance of the sympathomimetic properties of DDT in potentiation. This ganglionic blocking agent produced an insignificant tendency to decrease the potentiated CC1₄- induced BSP retention. However, the histologic evidence of protection against CC1₄ -induced hepatic necrosis was not apparent in mecamylamine-pretreated animals. Thus, the central sympathetic nervous system stimulatory effects of DDT are probably not directly involved in potentiation. The basis for extrapolation of these results from rat to man could be the total DDT body burden, which was similar in these rats (6.1 -30.6 ppm) to that estimated for man, e.g., 10 ppm by Durham (1965). Since rats and man respond similarly to CC1₄, these results indicate that man's chronic exposure to DDT could render him highly susceptible to a secondary exposure to CC1₄. Close

• 12289. [Article] Avian Radar Baseline Study: Final Survey Report for the Proposed Reedsport Ocean Power Technologies Wave Park

  Geo-Marine, Inc. (GMI) conducted an offshore avian radar baseline study for Oregon Wave Energy Trust (OWET) for a wave energy study located northwest of Reedsport, Oregon from 25 August through 29 October ...

  Citation × Citation Citation Abstract Copy Title: Avian Radar Baseline Study: Final Survey Report for the Proposed Reedsport Ocean Power Technologies Wave Park Author: Geo-Marine, Inc. Geo-Marine, Inc. (GMI) conducted an offshore avian radar baseline study for Oregon Wave Energy Trust (OWET) for a wave energy study located northwest of Reedsport, Oregon from 25 August through 29 October 2010. The study was conducted from shore with GMI’s Mobile Avian Radar System (MARS®). The MARS® was equipped with a 3-centimeter (cm) wavelength 50-kilowatt (kW) radar with a 2.5-degree (°) parabolic antenna for horizontal scanning, and a 3-cm, 25-kW radar with an open array antenna for vertical scanning. Diurnal land-based nearshore and diurnal and nocturnal boat-based radar validation surveys were conducted specifically to determine whether the radar could detect birds flying at low attitudes above the water. Comparison between the nearshore and offshore (study area) observer bird passage rates and the nearshore and offshore radar passage rates revealed low correlation between diurnal observations and radar data. The correlation analysis values were all too low (<.307) to develop a correction factor to apply to the radar data. Sea clutter was identified as the limiting factor. When algorithms to reduce false tracks from sea clutter were applied, tracks of real birds were eliminated because they could not be separated from sea clutter false tracks. At present there is no technology known that can accurately remove bird detections from sea clutter. This problem was further magnified in this study because radar visual validation surveys revealed that a major portion of the bird movement both nearshore and offshore occurred at altitudes from 1-30 feet (ft) above sea level. At that altitude it is impossible to separate birds from wind-driven waves and high swells that are common in the study area during fall. The visual validation data documented that the radar was ineffective when birds were flying close to the surface. In addition to providing data to facilitate passage rate comparisons between observer and the radar, the radar validation surveys provided data on bird flight behaviors within and adjacent to the study area. These data, which were requested to be collected for this study, included information on nearshore and offshore (study area) bird species occurrence, passage rates, flight altitudes and speeds, flight directions, and flock sizes. During the diurnal land-based nearshore avian surveys 43 bird species were identified; 32 bird species were observed during the boat-based offshore surveys. One federally-listed bird species, Marbled Murrelet (threatened), was observed occasionally during nearshore and offshore surveys. Diurnal nearshore bird passage rates ranged from 30-390 birds/nautical mile (NM)/hour (hr) from 0 to 1 NM offshore and from 10-142 birds/NM/hr from 1 to 2 NM offshore. Offshore (study area) passage rates ranged from 142-268 birds/NM/hr; offshore nocturnal passage rates ranged from 3-53 birds/NM/hr. The majority of birds flying over both nearshore (94%) and offshore (93%) waters were flying from 1-100 ft above sea level (asl). The majority of these birds were flying from 1-30 ft asl (nearshore, 75%; offshore, 83%). The dominant flight directions were to the south and the majority of birds sighted were in the 1-5 flock category. This Avian Radar Baseline Study was contracted to assist in collecting data that could potentially be used to meet these requirements. Avian radar validation surveys were designed specifically by GMI for this study to determine the accuracy of the radar data in predicting the number of birds that would potentially collide with the 30-ft tall wave buoys. The results of the avian radar validation surveys from this study indicate that avian radar is not able to collect accurate altitude flight data within the potential bird-wave power buoy collision zone (1-30 ft asl) because of the presence of sea clutter (high wind waves and/or swells) in the study area; however, diurnal avian radar validation bird survey data collected from shore and from a boat in the study area provided information requested by the Scope of Work including on nearshore and offshore (study area) species occurrence, avian passage rates (number of bird tracks/NM/hr), frequency of avian flight altitudes within and above the bird-wave power buoy collision zone, flock size frequency, and flight direction frequency. In addition, a nocturnal thermal imaging camera was used to conduct nighttime avian studies and provided data on nighttime bird passage rates. GMI recommends, based on the findings of this Avian Radar Baseline Study, that seasonal radar studies recommended by the FERC Study Plan be replaced with diurnal boat surveys and nocturnal boat surveys using stabilized remote sensing technologies (e.g., thermal imaging, high definition cameras). These methods will, in GMI’s opinion, provide the best data on nocturnal passage rate (bird abundance) and altitude use within the potential bird-wave power buoy collision zone (1-30 ft asl). Title: Avian Radar Baseline Study: Final Survey Report for the Proposed Reedsport Ocean Power Technologies Wave Park Author: Geo-Marine, Inc. Geo-Marine, Inc. (GMI) conducted an offshore avian radar baseline study for Oregon Wave Energy Trust (OWET) for a wave energy study located northwest of Reedsport, Oregon from 25 August through 29 October 2010. The study was conducted from shore with GMI’s Mobile Avian Radar System (MARS®). The MARS® was equipped with a 3-centimeter (cm) wavelength 50-kilowatt (kW) radar with a 2.5-degree (°) parabolic antenna for horizontal scanning, and a 3-cm, 25-kW radar with an open array antenna for vertical scanning. Diurnal land-based nearshore and diurnal and nocturnal boat-based radar validation surveys were conducted specifically to determine whether the radar could detect birds flying at low attitudes above the water. Comparison between the nearshore and offshore (study area) observer bird passage rates and the nearshore and offshore radar passage rates revealed low correlation between diurnal observations and radar data. The correlation analysis values were all too low (<.307) to develop a correction factor to apply to the radar data. Sea clutter was identified as the limiting factor. When algorithms to reduce false tracks from sea clutter were applied, tracks of real birds were eliminated because they could not be separated from sea clutter false tracks. At present there is no technology known that can accurately remove bird detections from sea clutter. This problem was further magnified in this study because radar visual validation surveys revealed that a major portion of the bird movement both nearshore and offshore occurred at altitudes from 1-30 feet (ft) above sea level. At that altitude it is impossible to separate birds from wind-driven waves and high swells that are common in the study area during fall. The visual validation data documented that the radar was ineffective when birds were flying close to the surface. In addition to providing data to facilitate passage rate comparisons between observer and the radar, the radar validation surveys provided data on bird flight behaviors within and adjacent to the study area. These data, which were requested to be collected for this study, included information on nearshore and offshore (study area) bird species occurrence, passage rates, flight altitudes and speeds, flight directions, and flock sizes. During the diurnal land-based nearshore avian surveys 43 bird species were identified; 32 bird species were observed during the boat-based offshore surveys. One federally-listed bird species, Marbled Murrelet (threatened), was observed occasionally during nearshore and offshore surveys. Diurnal nearshore bird passage rates ranged from 30-390 birds/nautical mile (NM)/hour (hr) from 0 to 1 NM offshore and from 10-142 birds/NM/hr from 1 to 2 NM offshore. Offshore (study area) passage rates ranged from 142-268 birds/NM/hr; offshore nocturnal passage rates ranged from 3-53 birds/NM/hr. The majority of birds flying over both nearshore (94%) and offshore (93%) waters were flying from 1-100 ft above sea level (asl). The majority of these birds were flying from 1-30 ft asl (nearshore, 75%; offshore, 83%). The dominant flight directions were to the south and the majority of birds sighted were in the 1-5 flock category. This Avian Radar Baseline Study was contracted to assist in collecting data that could potentially be used to meet these requirements. Avian radar validation surveys were designed specifically by GMI for this study to determine the accuracy of the radar data in predicting the number of birds that would potentially collide with the 30-ft tall wave buoys. The results of the avian radar validation surveys from this study indicate that avian radar is not able to collect accurate altitude flight data within the potential bird-wave power buoy collision zone (1-30 ft asl) because of the presence of sea clutter (high wind waves and/or swells) in the study area; however, diurnal avian radar validation bird survey data collected from shore and from a boat in the study area provided information requested by the Scope of Work including on nearshore and offshore (study area) species occurrence, avian passage rates (number of bird tracks/NM/hr), frequency of avian flight altitudes within and above the bird-wave power buoy collision zone, flock size frequency, and flight direction frequency. In addition, a nocturnal thermal imaging camera was used to conduct nighttime avian studies and provided data on nighttime bird passage rates. GMI recommends, based on the findings of this Avian Radar Baseline Study, that seasonal radar studies recommended by the FERC Study Plan be replaced with diurnal boat surveys and nocturnal boat surveys using stabilized remote sensing technologies (e.g., thermal imaging, high definition cameras). These methods will, in GMI’s opinion, provide the best data on nocturnal passage rate (bird abundance) and altitude use within the potential bird-wave power buoy collision zone (1-30 ft asl). Close

• 12290. [Article] Biases in droplet radii and optical depths of marine stratocumulus retrieved from MODIS imagery

  The 2007 Intergovernmental Panel on Climate Change assessment established that the effect of clouds on climate contributes the largest uncertainty in predicting the future climate. Satellite observations ...

  Citation × Citation Citation Abstract Copy Title: Biases in droplet radii and optical depths of marine stratocumulus retrieved from MODIS imagery Author: Boeke, Robyn C. The 2007 Intergovernmental Panel on Climate Change assessment established that the effect of clouds on climate contributes the largest uncertainty in predicting the future climate. Satellite observations provide an opportunity for learning about the behavior of clouds. This thesis seeks to assess the accuracy of cloud properties retrieved from multispectral satellite imagery and test the usefulness of satellite data in verifying conclusions based on aircraft observations that marine stratus appear to be formed through the nearly adiabatic ascent of moist air. Retrievals of cloud optical depth, a measure of cloud thickness, using 0.64-μm reflectances and droplet radii using separately 1.6, 2.1, and 3.7-μm reflectances were obtained with the MODerateresolution Imaging Spectroradiometer (MODIS). Owing to different amounts of absorption by liquid water in the near infrared, with the least at 1.6 μm and the most at 3.7 μm, the growth of droplet radius with cloud thickness should result in the largest droplet radii retrieved using the 3.7-μm reflectances and the smallest using 1.6-μm reflectances. Droplet radii retrieved using the 2.1-μm reflectances, however, are often the largest, and those retrieved using 3.7-μm reflectances are often the smallest. In addition aircraft observations indicate that the relationships between droplet radius, re, and optical depth, t, d ln r / d lnt e ,should be approximately equal to 0.2 for marine stratocumulus. While satellite observations in optically thick, overcast regions yielded d ln re/d ln t consistent with this result, retrievals for regions with broken clouds often yielded d ln r / d lnt e substantially smaller than 0.2. Clouds often exhibit large horizontal and vertical variability. In this thesis a simple radiative transfer model was used to predict reflectances at visible and near infrared wavelengths for clouds formed through the adiabatic ascent of moist air, and then a retrieval scheme based on vertically uniform clouds was used to determine if the departures from the behavior expected for adiabatic clouds might be caused by the assumption of spatial uniformity used in the retrievals. The simulations indicated that at all cloud thicknesses the progression of droplet size using 1.6, 2.1, and 3.7-μm reflectances followed that suggested by the absorptive properties of liquid water. The simulation also indicated, however, contrary to the observations, that when the clouds were optically thin, d ln r / d lnt e should be greater than 0.2, the value expected for the adiabatic ascent of moist air. The simulation was adapted to account for the effects of horizontal variations within clouds. Each 1-km pixel was given a subpixel distribution of optical depths based on a gamma distribution with mean taken from MODIS pixel-scale optical depths and variance given by Kato et al. (2006), obtained from Large Eddy Simulations of marine stratocumulus. Each subpixel was allowed to develop vertically following the adiabatic ascent of moist air. The average of the reflectances for the subpixels was used to retrieve the cloud properties for the pixels, and these properties were compared with the average properties of the subpixels. The retrievals obtained using 1.6-μm reflectances were most strongly affected by the addition of subpixel variations in optical depth and droplet radius. Mean droplet radius retrieved in the simulation was largest when using 1.6-μm reflectances, followed by that retrieved using 2.1 and 3.7-μm reflectances. The simulation of large droplet radii at the shorter wavelengths indicated that the large droplets observed in MODIS may result from horizontal variations within the 1-km MODIS pixel. The values of d ln r / d lnt e calculated for horizontally heterogeneous clouds were close to 0.2, but showed variations that extend both above and below this value, consistent with the MODIS observations. To illustrate the findings based on the simulations, visible optical depth and droplet radius were retrieved for MODIS 500-m pixels overcast by marine stratocumulus. The 500-m pixels were used to represent the subpixel variability within 2-km pixels constructed from the 500-m pixels. Differences between cloud properties retrieved using average radiances and averages of the subpixel properties were compared for overcast and broken-cloud regions using both MODIS and the Partly Cloudy Pixel Retrieval (PCPR) schemes for identifying the overcast 2-km pixels. In the regions overcast by optically thick marine stratocumulus, both methods of identifying overcast pixels led to small biases in the retrieved droplet radii and optical depths. Values of d ln r / d lnt e obtained in the overcast regions using the PCPR identifications were closer to the value of 0.2 expected for adiabatic clouds than those obtained using MODIS identifications. Additionally, values of d ln r / d lnt e calculated using the 500-m overcast pixels yielded better results than those calculated using the 2-km pixels. In regions containing broken clouds, the PCPR identification provided a smaller bias than the MODIS identification, however both methods showed greater biases than those calculated for regions overcast by optically thick marine stratocumulus. Values of d ln r / d lnt e for the regions containing broken clouds showed a positive value when using the PCPR scheme to identify overcast pixels, and a negative value when using the MODIS cloud mask to identify overcast pixels. Consistent with the results from the overcast regions, the d ln r / d lnt e obtained for the 500-m overcast pixels were in closer conformity with adiabatic clouds than the values obtained for the 2-km pixels using both the MODIS and PCPR identifications. Title: Biases in droplet radii and optical depths of marine stratocumulus retrieved from MODIS imagery Author: Boeke, Robyn C. The 2007 Intergovernmental Panel on Climate Change assessment established that the effect of clouds on climate contributes the largest uncertainty in predicting the future climate. Satellite observations provide an opportunity for learning about the behavior of clouds. This thesis seeks to assess the accuracy of cloud properties retrieved from multispectral satellite imagery and test the usefulness of satellite data in verifying conclusions based on aircraft observations that marine stratus appear to be formed through the nearly adiabatic ascent of moist air. Retrievals of cloud optical depth, a measure of cloud thickness, using 0.64-μm reflectances and droplet radii using separately 1.6, 2.1, and 3.7-μm reflectances were obtained with the MODerateresolution Imaging Spectroradiometer (MODIS). Owing to different amounts of absorption by liquid water in the near infrared, with the least at 1.6 μm and the most at 3.7 μm, the growth of droplet radius with cloud thickness should result in the largest droplet radii retrieved using the 3.7-μm reflectances and the smallest using 1.6-μm reflectances. Droplet radii retrieved using the 2.1-μm reflectances, however, are often the largest, and those retrieved using 3.7-μm reflectances are often the smallest. In addition aircraft observations indicate that the relationships between droplet radius, re, and optical depth, t, d ln r / d lnt e ,should be approximately equal to 0.2 for marine stratocumulus. While satellite observations in optically thick, overcast regions yielded d ln re/d ln t consistent with this result, retrievals for regions with broken clouds often yielded d ln r / d lnt e substantially smaller than 0.2. Clouds often exhibit large horizontal and vertical variability. In this thesis a simple radiative transfer model was used to predict reflectances at visible and near infrared wavelengths for clouds formed through the adiabatic ascent of moist air, and then a retrieval scheme based on vertically uniform clouds was used to determine if the departures from the behavior expected for adiabatic clouds might be caused by the assumption of spatial uniformity used in the retrievals. The simulations indicated that at all cloud thicknesses the progression of droplet size using 1.6, 2.1, and 3.7-μm reflectances followed that suggested by the absorptive properties of liquid water. The simulation also indicated, however, contrary to the observations, that when the clouds were optically thin, d ln r / d lnt e should be greater than 0.2, the value expected for the adiabatic ascent of moist air. The simulation was adapted to account for the effects of horizontal variations within clouds. Each 1-km pixel was given a subpixel distribution of optical depths based on a gamma distribution with mean taken from MODIS pixel-scale optical depths and variance given by Kato et al. (2006), obtained from Large Eddy Simulations of marine stratocumulus. Each subpixel was allowed to develop vertically following the adiabatic ascent of moist air. The average of the reflectances for the subpixels was used to retrieve the cloud properties for the pixels, and these properties were compared with the average properties of the subpixels. The retrievals obtained using 1.6-μm reflectances were most strongly affected by the addition of subpixel variations in optical depth and droplet radius. Mean droplet radius retrieved in the simulation was largest when using 1.6-μm reflectances, followed by that retrieved using 2.1 and 3.7-μm reflectances. The simulation of large droplet radii at the shorter wavelengths indicated that the large droplets observed in MODIS may result from horizontal variations within the 1-km MODIS pixel. The values of d ln r / d lnt e calculated for horizontally heterogeneous clouds were close to 0.2, but showed variations that extend both above and below this value, consistent with the MODIS observations. To illustrate the findings based on the simulations, visible optical depth and droplet radius were retrieved for MODIS 500-m pixels overcast by marine stratocumulus. The 500-m pixels were used to represent the subpixel variability within 2-km pixels constructed from the 500-m pixels. Differences between cloud properties retrieved using average radiances and averages of the subpixel properties were compared for overcast and broken-cloud regions using both MODIS and the Partly Cloudy Pixel Retrieval (PCPR) schemes for identifying the overcast 2-km pixels. In the regions overcast by optically thick marine stratocumulus, both methods of identifying overcast pixels led to small biases in the retrieved droplet radii and optical depths. Values of d ln r / d lnt e obtained in the overcast regions using the PCPR identifications were closer to the value of 0.2 expected for adiabatic clouds than those obtained using MODIS identifications. Additionally, values of d ln r / d lnt e calculated using the 500-m overcast pixels yielded better results than those calculated using the 2-km pixels. In regions containing broken clouds, the PCPR identification provided a smaller bias than the MODIS identification, however both methods showed greater biases than those calculated for regions overcast by optically thick marine stratocumulus. Values of d ln r / d lnt e for the regions containing broken clouds showed a positive value when using the PCPR scheme to identify overcast pixels, and a negative value when using the MODIS cloud mask to identify overcast pixels. Consistent with the results from the overcast regions, the d ln r / d lnt e obtained for the 500-m overcast pixels were in closer conformity with adiabatic clouds than the values obtained for the 2-km pixels using both the MODIS and PCPR identifications. Close