Search
Search Results
-
1921. [Article] Influences of clearcut logging on macroinvertebrates in perennial and intermittent headwaters of the Central Oregon Coast Range
This research was designed to broaden the understanding of how timber-harvest affects aquatic macroinvertebrates in perennial and intermittent headwater streams. This study compared emergent and benthic ...Citation Citation
- Title:
- Influences of clearcut logging on macroinvertebrates in perennial and intermittent headwaters of the Central Oregon Coast Range
- Author:
- Banks, Janel
This research was designed to broaden the understanding of how timber-harvest affects aquatic macroinvertebrates in perennial and intermittent headwater streams. This study compared emergent and benthic macroinvertebrate assemblages from 20 headwater streams in the central Oregon Coast Range that varied by harvest condition and flow duration. Through comparison of the community and functional characteristics of the macroinvertebrates in similar streams under different harvest conditions, logging impacts on adult and immature aquatic macroinvertebrates in perennial and intermittent streams were assessed. Adult insects emerging from the 20 study streams were collected using emergence traps set for four weeks in a 40-meter reach during three sampling periods: August-September 2003, October-November 2003, and April-May 2004. Adult aquatic insects were identified to genus and family taxonomic levels and results were expressed as number of individuals emerging per m2 per day. Benthic samples were taken from each reach in May 2004, insects and non-insects were identified to various taxonomic levels, and results were expressed as number of individuals per m2. Ten streams were located in catchments that were clearcut to the stream bank no more than a year before sampling began; three of these streams were intermittent and seven were perennial. Intermittent streams were summer-dry and retained surface-water for a minimum of eight months during the year, while perennial streams had surface flow year-round. The other ten streams (four intermittent and six perennial) were located in forested catchments that have not been logged for at least 34 years. The physical habitat of each stream reach was assessed in August 2003. Regardless of flow-duration or season, more aquatic insects emerged from streams in logged catchments. The emergence rate of Diptera, predominantly Chironomidae, was especially high from clearcut sites. More Trichoptera also emerged from clearcut sites. Ephemeroptera and Plecoptera did not emerge at rates that varied by logging condition. Plecoptera had higher emergence from intermittent than perennial sites in spring. Taxa richness was higher at clearcut sites, driven primarily by rare taxa encountered in less than 5 of the 10 clearcut sites. Emergent insect functional feeding group composition was affected by harvest condition with collector-filterers emerging at higher rates from clearcut sites. Examination of community patterns through nonmetric multidimensional scaling (NMS) ordination analyses indicated that emergent aquatic macroinvertebrate assemblages differ by season and by harvest condition. The duration of stream flow did not strongly influence adult assemblages. Channel dimensions (active channel and bankfull width) and catchment area were correlated with ordination-axes, but were not different between logged and forested sites. The amount of riparian cover (canopy, understory, and groundcover), stand age, slash, and stream cover were all considerably different between logged and forested sites and were highly influential on emergent assemblages. Substrate size was also influential on adult assemblages. Mean water temperature in summer, fall, and spring was highly correlated with seasonal variation in assemblages. Regardless of harvest-condition, intermittent streams had higher overall benthic macroinvertebrate density. Trichoptera had higher densities at intermittent sites than perennial sites, while Diptera, Plecoptera, and non-insects had similar densities between categories of flow duration and harvest condition. Benthic macroinvertebrate functional composition was also affected by flow-duration, with collector-filterers, collector-gatherers, and predators occurring at higher densities at intermittent sites than perennial sites. The densities of scrapers and shredders did not differ between classes of flow duration or harvest condition. The majority of taxa (72%) were common to both perennial and intermittent sites; however, taxa richness was lower at intermittent sites. NMS-ordination analyses of the benthic macroinvertebrates showed that community patterns differed by harvest condition within the perennial flow-duration class. Benthic communities of intermittent streams did not differ between harvest conditions. Channel dimensions (active channel and bankfull width), mean substrate diameter, percent stream-cover, mean water temperature, elevation, and percent small riparian trees influenced benthic community assemblages. The majority of perennial-clearcut sites had macroinvertebrate community patterns more similar to intermittent-forested and intermittent-clearcut streams than to perennial-forested sites. The two perennial-clearcut sites that did not have benthic assemblages similar to the other five perennial-clearcut sites had larger diameter substrate, higher elevation, larger catchment area, and cooler mean water temperature than other perennial-clearcut sites. This study provides evidence that Oregon’s current timber harvesting practices impact macroinvertebrate assemblages of perennial and intermittent headwaters in the Central Oregon Coast Range within a year following harvest. When the studied streams were clearcut to the streambank, there was increased emergence of adult macroinvertebrates, principally midges, at clearcut sites. Benthic assemblages differed primarily between intermittent and perennial flow-duration. However, within flow-classes, assemblages of benthic aquatic macroinvertebrates in perennial streams were impacted by clearcut logging to a higher degree than intermittent streams. Perennial-clearcut streams had different benthic assemblages from perennial-mature streams and perennial-clearcut streams with coarser substrate and cooler temperatures. Intermittent streams, which generally experience fewer flushing events and accumulate finer substrates than perennial streams, may be affected to a lesser degree by any sedimentation caused by logging activity. Correlations of emergent and benthic macroinvertebrate communities with the measured environmental gradients are suggestive that reduced canopy cover and substrate composition are major influential factors.
-
1922. [Article] Cruise ship disturbance to Kittlitz's murrelets (Brachyramphus brevirostris) in Glacier Bay National Park and Preserve, Alaska
The Kittlitz's murrelet (Brachyramphus brevirostris), a small pursuit-diving seabird in the family Alcidae, occurs across much of coastal Alaska and parts of the Russian Far East. Glacier Bay National ...Citation Citation
- Title:
- Cruise ship disturbance to Kittlitz's murrelets (Brachyramphus brevirostris) in Glacier Bay National Park and Preserve, Alaska
- Author:
- Marcella, Timothy K.
The Kittlitz's murrelet (Brachyramphus brevirostris), a small pursuit-diving seabird in the family Alcidae, occurs across much of coastal Alaska and parts of the Russian Far East. Glacier Bay National Park, located in Southeast Alaska, is believed to support approximately 37% of the worldwide breeding population of Kittlitz's murrelets during the summer months. Recent concern over apparent population declines in Alaska, coupled with the Park's dual mandate of resource preservation and visitation, led to this study. Cruise ships, although not the most numerous vessel type operating in Glacier Bay, have previously been identified as the vessel type eliciting the greatest disturbance response from Kittlitz's murrelets. During the murrelet breeding seasons in 2011 and 2012, my field assistants and I collected focal observations of 4,251 Brachyramphus murrelets from the bow of cruise ships traveling through Glacier Bay. Identification of murrelets to species was hampered by both the distance at which murrelets responded to the approaching ship and the type of response to the ship (diving vs. flushing). For roughly 40% of focal observations of murrelets from cruise ships, the species of murrelet (Kittlitz's murrelet or marbled murrelet [B. marmoratus]) could not be identified. Apparent habitat partitioning by the two murrelet species in Glacier Bay resulted in 79% of identified murrelets in the upper section of the Bay (Upper Bay) being Kittlitz's murrelets, while 83% of identified murrelets in the lower section of the Bay (Lower Bay) were marbled murrelets. In the Upper Bay, cruise ships are predicted to disturb 61% of all murrelets within 850 m on either side of the cruise ship's course (i.e., elicited a flushing or diving response), whereas in the Lower Bay, cruise ships are predicted to disturb 72% of murrelets within 850 m of the ship's course. Using Cox multistate models, I demonstrated that murrelets in the Upper Bay (predominantly Kittlitz's murrelets) were more likely to dive than flush in response to approaching cruise ships, whereas murrelets in the Lower Bay (predominantly marbled murrelets) were more likely to flush than dive. Also, murrelets in the Upper Bay responded to cruise ships by flushing or diving at shorter distances from the ship compared to murrelets in the Lower Bay. Murrelets in both areas of Glacier Bay generally reacted to cruise ships at greater distances when the ship approached indirectly, presumably because of the larger profile presented by a passing ship as opposed to a directly advancing ship. Absolute distance of the cruise ship from a focal murrelet was a strong predictor of murrelet disturbance response; no other management-relevant covariates that were measured during this study (e.g., ship velocity, distance to shore, whether a cruise ship had entered the Bay earlier that day) explained a significant proportion of the variation in murrelet response. Inferences based on data collected on-board cruise ships were limited to murrelet disturbance responses that occurred within 1 km of the ship. This was because of limits to the distance from the ship at which behavioral responses could be observed and the a priori assumption that disturbance to murrelets by cruise ships was unlikely at distances greater than 1 km. Results from shipboard observations indicated that some proportion of murrelets encountered at the farthest distance we could make inferences were on occasion disturbed (point estimate at 850 m perpendicular distance from ship's course = 15-30% probability of flushing or diving). This suggests that disturbance of murrelets by cruise ships in Glacier Bay exceeded expected distance thresholds. In order to investigate the effects of cruise ships on murrelet behavior at distances greater than 1 km, my assistants and I collected a total of 643 focal observations of Kittlitz's murrelets during 181 hours of observation from land-based observation sites in the Upper Bay during the 2012 field season. By combining these data with AIS and GPS ship tracks, I was able to append distance to the nearest cruise ship to each focal murrelet observation and search for patterns in murrelet behavior. By collecting data in this manner, I was able to avoid biasing the study based on pre-conceived notions of what constituted a threshold distance for cruise ships to disturb Kittlitz's murrelets. Using a segmented regression model within a logistic regression framework, I found that Kittlitz's murrelets exhibited a disturbance threshold (defined as an increased incidence of flushing from the water) by cruise ships at distances of at least 1.6 km, and perhaps as great as 6.0 km, with a best estimate of threshold disturbance distance at 3.8 km from a cruise ship. When cruise ships were greater than 3.8 km from focal Kittlitz's murrelets, the baseline probability of murrelets flushing during a focal observation period was 12.5%. When cruise ships were less than 3.8 km from focal Kittlitz's murrelets, the probability of flushing increased logistically with decreasing distance to an estimated 48% for the closest approach distances. The unexpectedly long distances at which murrelet behavior was affected by cruise ships in Glacier Bay is most likely attributable to social facilitation by other disturbed murrelets, because similar numbers of murrelets flushed when cruise ships were approaching (n = 30) as when they were receding (n = 27). Once a Kittlitz's murrelet flushed from the water, the subsequent duration of flight did not vary with distance to the nearest cruise ship. Instead, the duration of Kittlitz's murrelet flight was associated with time of day. The strong association between the proximity of cruise ships and the probability of a murrelet flushing, even at distances of several kilometers, demonstrates that Kittlitz's murrelets in Glacier Bay are susceptible to disturbance from cruise ships at distances greater than has previously been published for any seabird.
-
1923. [Article] The illicit use of prescription stimulants on college campuses : a theoretical examination
The illicit use of prescription stimulants (IUPS) is a critical Public Health problem in the college population that represents a unique form of substance use. Namely, the primary motives for IUPS by college ...Citation Citation
- Title:
- The illicit use of prescription stimulants on college campuses : a theoretical examination
- Author:
- Bavarian, Niloofar
The illicit use of prescription stimulants (IUPS) is a critical Public Health problem in the college population that represents a unique form of substance use. Namely, the primary motives for IUPS by college students are academic in nature (e.g., Teter, McCabe, LaGrange, Cranford, & Boyd, 2006), which may explain why usage rates as high as 43% have been reported on college campuses (Advokat, Guidry, & Martino, 2008). As the field of IUPS is in its infancy, the IUPS-literature lacks 1) a consistent definition of "illicit use of prescription stimulants", 2) an instrument designed to assess the multiple influences on IUPS behavior, and 3) a theoretical lens (Bavarian, 2010a). Accordingly, the goal of this study was to address these research gaps by examining IUPS at one university located in the Pacific Northwest using the theory of triadic influence (TTI; Flay & Petraitis, 1994; Flay, Snyder, & Petraitis, 2009), an integrated, ecological approach to explaining and predicting health behaviors. The study included five phases of research. The first phase began with a systematic approach to measurement development resulting in a 97-item preliminary instrument, the Behaviors, Expectancies, Attitudes and College Health Questionnaire (BEACH-Q). The measure was reviewed by the dissertation committee, leading to revisions in content and structure. During phase II, the BEACH-Q was evaluated by a convenience sample of five health and measurement professionals, and results suggested good content validity of the instrument (i.e. 35 of the 37 TTI-based covariates received a median rating between "agree" and "strongly agree", and 34 received a mean rating between "agree" and "strongly agree"). In phase III (instrument review by a convenience sample of six undergraduates), all 37 covariates received a median and mean rating between "agree" and "strongly agree", confirming good face validity. In phase IV, one undergraduate classroom was selected to participate in a pilot test of the BEACH-Q, using test-retest methodology. Results from the pilot (N = 39) showed that the instrument had moderate to high internal consistency reliability and modest to high stability reliability. In phase V, the final 96-item version of the BEACH-Q was administered throughout campus using one-stage cluster sampling, with classrooms as the sampling unit and students as the observation unit (N = 520 students in 20 classrooms, eligible student response rate = 96.30%). The prevalence of IUPS during college self-reported by the phase V sample was 25.58%, and the probability of engaging in IUPS did not differ between classrooms (Median Odds Ratio = 1.00). In crude logistic regressions, 24 out of 37 hypothesized theoretical covariates were significantly associated with IUPS in the expected direction, suggesting predictive validity of the BEACH-Q. Nested logistic regression analyses illustrated that, for the full multivariate model including ultimate, distal, and proximal covariates, the following measures in the intrapersonal stream were significantly associated with IUPS during college: race/ethnicity, year in school, academic concern, academic grades, diagnosis with Attention Deficit Disorder, and IUPS avoidance self-efficacy. Significant social situation/context stream covariates in the full model included: residence, varsity sports participation, perceptions of IUPS by friends, family, and faculty, endorsement of IUPS by friends, and perceived prevalence of IUPS among friends. With respect to the sociocultural environment stream, in the full multivariate model, the following covariates were found to be significantly associated with IUPS: financial-related stress, participation in religious activities, positive IUPS expectancies, prescription stimulant knowledge and perceived costs/benefits of IUPS. Lastly, intention to engage in IUPS (an immediate precursor) was positively associated with IUPS. Structural equation modeling was used to test models of IUPS for each of the three streams, as well as one integrated model that included covariates from each stream. The models all demonstrated good model fit, and provided insight into the factors that influence (and suggest the mechanisms of causation) intentions to engage in, and ultimately the behavior of, IUPS. In the intrapersonal stream model, inattention was positively associated with academic concern and inversely associated with avoidance self-efficacy, and avoidance self-efficacy was inversely associated with intentions to engage in IUPS. Moreover, intentions to engage in IUPS and avoidance self-efficacy were both significantly associated with IUPS. In the social situation/context stream model, living on-campus was negatively associated with friends' endorsement of IUPS which was positively associated with perceived prevalence of IUPS among friends, and perceived prevalence was positively associated with intentions to engage in IUPS; all of the direct paths to IUPS, excepting the path from perceived prevalence of IUPS among friends, were significant. In the sociocultural environment model, perception of course demand was significantly associated with both the perception that professors give the most attention to top academic students and attitudes about the impact of prescription stimulants on academics, and these attitudes had a positive association with intentions to engage in IUPS. Moreover, the direct paths from attitudes and intentions to IUPS were significant. The mixed model, including participation in religious activities (sociocultural environment stream), friends' endorsement of IUPS (social situation/context stream), and avoidance self-efficacy (intrapersonal stream), also had significant paths from ultimate to distal to proximal to immediate precursor, and significant direct paths to IUPS. This study successfully achieved its goals. First, the instrument developed was theory-driven, broadly defined IUPS, and was psychometrically strong. The cross-sectional study illustrated that IUPS was prevalent on the campus under investigation, as one in four students had engaged in the behavior during college. Associations of use with theoretical correlates were tested for, and structural equation modeling was used to support one premise of the TTI (i.e. that behavior is multifaceted, and covariates from different streams may interact to influence behavior). The findings also suggest that prevention and intervention plans should be multifaceted in nature. Given that this study's cross-sectional nature limited the ability to make causal inferences, future research involving the BEACH-Q should use longitudinal designs.
-
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
- 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.
-
Clostridium perfringens is a Gram-positive, anaerobic, spore-forming bacterium that can produce as many as 17 different toxins and are responsible to cause a wide array of gastrointestinal (GI) and histotoxic ...
Citation Citation
- Title:
- Characterization of Sporulation and Germination Genes in Clostridium perfringens
- Author:
- Talukdar, Prabhat Kumar
Clostridium perfringens is a Gram-positive, anaerobic, spore-forming bacterium that can produce as many as 17 different toxins and are responsible to cause a wide array of gastrointestinal (GI) and histotoxic diseases in humans and animals. As individual strains produce a subset of these toxins, C. perfringens strains can be classified into five toxinotypes (A-E). C. perfringens type A strains that produce C. perfringens enterotoxin (CPE) cause food-poisoning (FP) and non-food borne (NFB) diseases in humans and domestic animals which account for a substantial amount of economic loss every year in the United States. To cause a wide variety of diseases in different hosts, C. perfringens possesses several unique characteristics; i) this bacterium is anaerobic and can survive in many conditions that are not regularly exposed to the air or has limited oxygen concentration, such as soil, sewage, GI tract of humans and animals, ii) it can form spores that are resistant to heat and other environmental stresses, iii) by sensing favorable conditions, spores of C. perfringens can rapidly transform into vegetative cells through a process called germination when conditions are favorable, and iv) it can produce variety of toxins in different conditions. Considering these unique features regarding C. perfringens survival in the environment and pathogenicity towards different hosts, it is important to identify genes and proteins that are involved in C. perfringens sporulation and germination process. Also, identification of potential germinant molecules is important to effectively kill spores with minimal effort. The studies conducted for this dissertation were focused to identify and characterize several putative germination and sporulation specific proteins as well as characterize germinant molecules for C. perfringens isolates from various sources. The initial focus of this dissertation was to investigate the role of two serine proteases of Csp family proteins, CspA and CspC, in C. perfringens spore germination. Previously, it has been shown that another serine protease CspB is involved in the processing of pro-SleC into mature, active SleC. SleC is a cortex lytic enzyme that is involved in the spore cortex hydrolysis in C. perfringens spore germination. Our current study demonstrated that i) cspA and cspC are transcribed as a bicistronic operon during the sporulation and the location of the transcripts are present in mother cell only, ii) both CspA and CspC have role in spore germination, as spores of double cspA-cspC and single cspC mutants exhibited very low extent of germination with different nutrient and non-nutrient germinants than wild-type and complemented strains, iii) cspA and cspC spores were defective in outgrowth and colony formation in nutrient rich media, iv) CspA and CspC are involved in spore cortex hydrolysis by processing of pro-SleC into active SleC, and finally v) CspA and CspC do not activate and regulate the levels of CspB. The second focus of this dissertation was to identify and characterize several putative sporulation proteins in C. perfringens FP strain SM101. Nine genes (ylzA, ymxH, spoIIM, ytxC, ylxY, ytaF, yyaC1, yyaC2 and bkdR) were identified based on the homology with respective genes in Bacillus subtilis. Among the selected genes, promoters of seven genes (ymxH, spoIIM, ytxC, ytaF, yyaC1, yyaC2 and bkdR) were expressed at different time points during sporulation as determined by β-glucuronidase assay. By using group-II intron based TargeTron technique, null mutations were inserted in seven genes (ymxH, spoIIM, ytxC, ytaF, yyaC1, yyaC2 and bkdR) and analyzed for spore formation and germination properties. Results from this study revealed that, ii) SpoIIM plays very crucial role in spore formation as no spores were produced by spoIIM mutant strain, ii) YmxH, YtxC, YtaF, YyaC1 and BkdR have minor role in spore formation as C. perfringens ymxH, ytxC, ytaF, yyaC1 and bkdR strains showed significantly reduced spore formation compared to the wild-type strain, and iv) YyaC2 and YtxC have roles in spore germination as lower germination rate and decreased DPA release compared to wild-type was observed with yyaC2 and ytxC mutant spores. The final focus of this dissertation was to identify the germinants for the spores of C. perfringens strains isolated from diseased animals and investigate the presence and expression of major germination genes in these animal isolates. Spores of C. perfringens animal isolates (horse isolates 106902 and 106903, pig isolates JGS1071 and JGS1807, dog isolates 294442 and 294443, and poultry isolates JGS4122 and JGS4125) were tested with different nutrient and non-nutrient germinants. Spores of C. perfringens animal isolates showed very low germination with different nutrient, non-nutrient germinants, rich media and cell culture media compared to human FP isolate SM101. When spores of four strains (106903, JGS1807, 294442, and JGS4122) of animal isolates were tested with all amino acids at pH 7.0 and pH 6.0, the germination rate varied among strains and was not consistent. However, most of the strains germinated better at pH 6.0 than at pH 7.0 with all amino acids tested. Germination assay with L-cysteine and L-lysine at different pHs (5.0 to 9.0) and different concentrations (1 mM to 200 mM) revealed that except strain JGS4122, all other strains did germinate better with higher concentrations of L-cysteine and L-lysine at pH range of 5.5-7.0. qRT-PCR analyses with RNA extracted from 8 h sporulation culture showed that level of expressions of gerKA, gerKB, gerKC and gerAA were higher in animal isolates compared to SM101. However, the transcript levels of cspA, cspB, cspC and sleC were lower in animal isolates. This finding was further confirmed by the quantitative Western blot analyses as the levels of both CspB and SleC was low in C. perfringens animal isolates than in human isolates. Together this finding suggests that C. perfringens animal isolates may have low activity in cortex hydrolysis that results in the lower spore germination. Collectively, our studies contribute towards understanding the mechanism of sporulation and germination in pathogenic bacterium C. perfringens by 1) dissecting the role of two new Csp proteases in C. perfringens spore germination; 2) identifying and characterizing new sporulation and germination genes in the pathogenic bacterium C. perfringens, and 2) characterizing germination of spores of C. perfringens isolated from diseased animals.
-
1926. [Article] Cover crop effects on root rot of sweet corn and soil properties
Root rot of sweet corn in western Oregon and Washington is a significant disease that can reduce yield of intolerant cultivars of processed sweet corn by fifty percent. Root rot is caused by a complex ...Citation Citation
- Title:
- Cover crop effects on root rot of sweet corn and soil properties
- Author:
- Miyazoe, Mikio
Root rot of sweet corn in western Oregon and Washington is a significant disease that can reduce yield of intolerant cultivars of processed sweet corn by fifty percent. Root rot is caused by a complex of soilborne organisms, including Drechslera sp., Phoma terrestris, and Pythium arrhenomanes. Processors have adopted tolerant cultivars but farmers continue to seek cultural management strategies that reduce inoculum potential. High rate manure and compost amendments (16.8 - 56.0 Mg ha⁻¹) suppress root rot of corn through general suppression but this practice is not agronomically viable. General suppression is typically associated with high rates of organic amendment and high microbial (FDA) activity. Processed vegetable farmers currently grow winter cover crops to improve soil and water quality and are interested in identifying cover crops that suppress root rot of corn and increase yield. High biomass cover crops can yield up to 12 Mg ha⁻¹ dry matter; this rate of organic amendment may or may not be sufficient to generate general suppression. However, specific cover crops, such as species and cultivars of crucifers and oats, have been shown to more suppressive than other cover crop species and cultivars against specific soilborne diseases. Oat is grown as a winter cover crop in the Willamette Valley and contains avenecin, a chemical that has been shown to have activity against pathogen propagules. In addition, in previous work in containers oat cover crops suppressed root rot of sweet corn. However, there is a concern that oat cover crops immobilize N and reduce corn yield. The objectives of this research were to 1) identify high biomass cover crops with agronomic potential for western Oregon processed vegetable cropping systems, 2) evaluate the impact of high biomass cover crops on root rot severity and yield of sweet corn, 3) determine whether there is a correlation between dry matter, soil microbial activity and root rot severity and 4) determine whether cover crops immobilize nitrogen and reduce corn yield. Research station field trials were conducted in 2003-04, 2004-05 and 2005-06 at the Oregon State University vegetable research farm in Corvallis, Oregon and an on-farm experiment was conducted in 2004-05 at Kenagy Family Farm in Albany, Oregon. Oat 'Saia' winter-killed in 2005-06 and mustard mix 'Caliente' winter-killed every winter except 2004-05, when winter temperatures never dropped below -7 °C. Rape 'Dwarf Essex', mustard 'Braco', and arugula are reliably winter-hardy. All mustard cover crop species are susceptible to white mold caused by Sclerotinia sclerotiorum, causal agent of white mold of snap bean. Oat (Avena sativa) is susceptible to barley yellow dwarf virus (BYDV), an important pathogen of grass seed crops. Mustard cover crops could contaminate cruciferous seed crops. All of the cover crop species evaluated demonstrated some potential to suppress root rot of corn. Oat 'Saia' was the most consistently suppressive; it suppressed root rot in 4 of 6 experiments. Sudangrass was suppressive in the only year it was evaluated as well as in container experiments in previous work. In general, cover crops increased or had no impact on shoot and root dry matter in greenhouse bioassays. There was only one significant cover crop treatment effect on yield; in 2006, the oat treatment increased yield by 11.6% compared to the fallow. Overall, cover crop aboveground dry matter (DM) ranged from 4.2 Mg ha⁻¹ (summer R 2003) to 12.2 Mg ha⁻¹ (winter O 2004). Overall, there was a significant relationship between cover crop DM and radicle rot severity in greenhouse bioassay but not in field experiment. Cover crop treatments consistently increased soil microbial activity. Overall, there was a significant negative correlation between microbial activity and root rot severity in greenhouse bioassays early after cover crop incorporation, but the correlation weakened over time and ultimately was lost by about 80 days after incorporation. The C:N of oat and rape residues was 51 and 21, respectively. Soil nitrogen was immobilized by both the oat and rape cover crops, but oat immobilized more N than rape. Corn grown in the oat treatment soils had lower SPAD values, but it is not clear whether foliar N was sufficiently low to reduce yield potential. There was no consistent trend in above- or below-ground corn dry matter after oat incorporation over the three years. In 2006, the oat treatment had no significant effect on corn DM but increased yield by 11.1%. More work is required to better understand the impact of oat cover crop N immobilization on corn N status and yield. Oat 'Saia' has the potential to suppress root rot of sweet corn and maintain or increase corn productivity. However, this oat cultivar is not reliably winter-hardy and is susceptible to BYDV. Future research should screen Avena species and/or cultivars for improved winter hardiness, BYDV resistance, and root rot suppressive potential.
-
Detailed geologic mapping in the Mormon Mountains and new geophysical data provide significant insight into contractional and extensional tectonics in southern Nevada, southwest Utah, and northwest Arizona. ...
Citation Citation
- Title:
- Structure of the southern Mormon Mountains, Clark County, Nevada and regional structural synthesis : fold-thrust and basin-range structure in southern Nevada, southwest Utah, and northwest Arizona
- Author:
- Carpenter, James Anthony
Detailed geologic mapping in the Mormon Mountains and new geophysical data provide significant insight into contractional and extensional tectonics in southern Nevada, southwest Utah, and northwest Arizona. The rocks in the region were complexly deformed during two distinct tectonic episodes. Numerous interrelated events occurred within each episode. The first tectonic episode, related to the Sevier orogeny, was characterized by east-west crustal shortening which culminated in thin-skinned decollement style folding and thrusting during the Cretaceous. The Virgin-Beaver Dam Mountains anticline, a Laramide-type basement-involved uplift, represents the only thick-skinned contractional structure in the region. The second tectonic episode, related to basin-range rifting, was characterized by east-west crustal extension which was accommodated by high-angle normal faults, with dips averaging 60 degrees, in the brittle upper crust. In this area, basin-range rifting initiated in the Oligocene and continued to Recent time. Relations in the North Muddy Mountains in southern Nevada suggest that the Muddy Mountain thrust sheet advanced and overrode the Weiser syncline during the Cenomanian and may have continued to advance in Turonian time. In the southern Mormon Mountains, the Cambrian Bonanza King Formation lies in the hanging wall flat position in thrust contact with the overturned Petrified Forest Member of the Triassic Chinle Formation at the footwall ramp. The thrust sheet advanced eastward more than 30 km from the place of origin. Thrust imbrication, and probably the formation of hanging wall horses, likely occurred as the Muddy Mountain thrust sheet encountered and ascended up the footwall ramp zone (composed largely of competent carbonate rocks) where slices of the thrust sheet (hanging wall horses) splayed of f and accreted to the footwall ramp zone. A detailed retrodeformable (balanced) regional structure section suggests that fold-thrust shortening at the latitude of the Mormon Mountains is a minimum of about 26%. Extension-related structures overprint older fold-thrust structures in the Mormon Mountains. The west-plunging east-trending Candy Peak syncline is one of a family of fold structures related to basin-range rifting. The syncline formed in pre-Miocene time in association with the northeast-striking Reber Mountain normal fault directly north and the northeast-striking Dry Canyon right-lateral strike-slip fault directly south. The Tortoise Flat synform, which lies southeast of the Dry Canyon fault, developed in Miocene and possibly Pliocene time by right-lateral flexure of early Miocene Horse Spring beds as a result of drag associated with the Dry Canyon fault. The Dry Canyon fault and the Tortoise Flat synform are interpreted to be part of the right-lateral Moapa Peak-Reber Mountain shear zone system in the southern Mormon Mountains. Therefore, the time of formation of the Moapa Peak-Reber Mountain shear zone system is pre-Miocene to possibly Pliocene. The shear zone system formed in response to different amounts of west-directed extension-related movement of the hanging wall block of the high-angle Virgin Beaver Dam Mountains fault, which initiated in the Oligocene. From this, the timing of the Moapa Peak-Reber Mountain shear zone, system is interpreted as Oligocene to Miocene, and possibly Pliocene. The interpretation of 261 km of seismic reflection sections suggests that large-displacement high-angle normal faults, typically with 60 degrees of dip, control horst and graben structure and accommodate extension by simple shear in the upper brittle crust. Such faults likely extend to depths of 15 to 18 km. Below this depth extension is thought to be accommodated by penetrative ductile deformation. A detailed retrodeformable (balanced) regional structure section suggests that basin-range extension at the latitude of the Mormon Mountains is about 17%. The Virgin-Beaver Dam Mountains high-angle normal fault is a large-displacement master fault in the area, having more than 8,000 in of normal vertical separation at the latitude of the Virgin Valley basin depocenter. Miocene doming and uplift of the Mormon Mountains occurred in response to displacement on the Virgin-Beaver Dam Mountains fault. The Virgin Valley basin formed as the hanging wall block downdropped, and the Mormon Mountains dome formed by relative uplift at the opposite end of the hanging wall block. Half-grabens, and tilted, folded, and faulted range blocks characterize basin-range crustal structure. Depositional growth relations are interpreted in basins from fanning-upward reflector geometry, and the wedge-shape of Oligocene to Recent syntectonic basin-fill sediments. Non-overlapping opposing east- and west-tilted half-grabens compose the Meadow Valley-California Wash basin. Seismic sections, gravity data, well data, and geologic mapping demonstrate that the Mormon Peak, Tule Springs Hills, and Beaver Dam/Castle Cliff "detachments," which were thought to be rooted low-angle normal faults, do not exist. The Mormon Peak and Beaver Dam/Castle Cliff low-angle normal faults are denudational fault planes below gravity slid masses. The widely distributed translocated Paleozoic blocks, which were thought to be remnant pieces of large hanging wall sheets ("extensional allochthons"), are disjunct rootless gravity slide blocks of minor tectonic significance. A large number of these rootless slide blocks lie on Pliocene and Quaternary basin-fill deposits. The Muddy Mountain-Tule Springs thrust, of Sevier age, was not reactivated as a crustal penetrating Tule Springs Hills low-angle normal fault, but is affected by small-scale gravity slide features. Rootless gravity slide blocks, secondary features to high-angle normal faults, commonly occur from instability as a result of the loss of lateral support induced by block faulting and the associated erosion of range blocks.
-
1928. [Article] Awareness of Aging in Taiwan and the United States : An Examination of Ageism among College Students using Stereotypes and Future Self-views
Ageism in the context of global population aging could lead to increasing human and economic costs. Age stereotypes tend to be negative (Hummert, 1990) and ubiquitous (Nelson, 2002) there are a variety ...Citation Citation
- Title:
- Awareness of Aging in Taiwan and the United States : An Examination of Ageism among College Students using Stereotypes and Future Self-views
- Author:
- Allen, Pamela M.
Ageism in the context of global population aging could lead to increasing human and economic costs. Age stereotypes tend to be negative (Hummert, 1990) and ubiquitous (Nelson, 2002) there are a variety of well documented detrimental consequences of negative age stereotypes on older adults' physical, cognitive and psychological outcomes (Hummert, 2011; Levy, 2009; Hess et al., 2003). This contributes to a toxic social environment for older people. The issue is of growing importance especially in Asia, where most of today's older people reside (United Nations, 2012) and where ageism appears to be on the rise despite traditional predictions that cultural collectivism and filial piety should protect against negative stereotypes (North & Fiske, 2015). Ageism is proposed by stereotype embodiment theory (Levy, 2009) to be driven by a lifespan process by which beliefs about aging are internalized from the sociocultural context of the individual beginning in childhood. In addition, age stereotypes and self-views related to aging assimilate such that age stereotypes also become internalized into one's self-view. Together, age stereotypes and self-views are components of one's overall subjective awareness of aging (AoA), an "integral psychological process or condition of the aging self" representing one's sense of having grown older (Diehl et al., 2014, p. 2). Depending on whether AoA is positive or negative it functions to enhance or constrict developmental opportunity throughout adult development, respectively. In early adulthood, a period characterized by identity consolidation (Côté, 2009; Erikson, 1968) and a developing future time orientation (Nurmi, 1991), age stereotypes stand to be internalized into one’s future oriented self-concept. Internalization of negative age stereotypes into young adults' future self-views (of one's self in old age) matters because it could give rise to negative AoA early in adulthood and developmental trajectories constraining healthy aging later in life. The cross-cultural ageism research in Western and Eastern societies has assessed stereotypes only and there has been little attention to future self-views (Markus & Nurius, 1986), developmental influences such as experiences with older people (Hagestad & Uhlenberg, 2005), or processes such as internalization by which negative stereotypes can become self-relevant (Levy, 2009). Conversely, the extant work examining internalization of age stereotypes into future self-views as of yet offers little insight into cultural or developmental factors for the processes of internalization (e.g., Kornadt & Rothermund, 2012). Therefore in this dissertation I draw on stereotype embodiment theory (Levy, 2009) and the Awareness of Aging model (Diehl et al., 2014), to examine the positivity of age stereotypes and future self-views among young adults in the U.S. and Taiwan. Data from the Cross-Cultural Perceptions of Aging Study were used to quantitatively measure experiential variables as well as the degree of positivity of age stereotypes and future self-views among 942 American and 659 Taiwanese college students using the Taiwanese developed Older Person Scale (OPS; Lu & Kao, 2009). The dissertation adapted the OPS for first time use in English before using it to examine how cultural context, personal experiences with older adults related to age segregation, and gender impact the positivity of age stereotypes and future self-views cross-culturally. Multiple group confirmatory factor analysis established partial scalar cross-cultural measurement invariance of 15-item and 17-item versions of the scale for measuring age stereotypes and future self-views, respectively. Results showed a four factor structure of the scale reflecting the domains of 1) physical abilities and appearance, 2) psychological and cognitive abilities, 3) interpersonal relationships and social engagement, and 4) employment and financial security. Content analyses of open ended descriptors of age stereotypes and future self-views among American college students provided a check on the assumption that the OPS captures content of these constructs in the population of American college students. Due to the superior psychometric properties of the OPS for measurement of the social domain, and relevance of this domain for experiences of intergenerational contact, the primary research questions were addressed with respect to the social domain. Results of moderated mediation modeling showed that, as hypothesized (hypothesis 1), Taiwanese participants exhibited less positivity in stereotypes and self-views in the psychological and social domains but not the physical or employment domains. Contrary to the expectation, Taiwanese age stereotypes were better characterized as slightly positive or ambivalent rather than negative. As predicted by hypothesis 2, females and those reporting regular experience of contact with older adults expressed more positivity in age stereotypes and future self-views in the social domain across cultural contexts. In support of hypothesis 3, age stereotypes mediated the association of 1) cultural context, and 2) contact frequency to the positivity of future self-views in the social domain. Exploratory results indicated that the strength of indirect effects did not vary significantly across cultural contexts or gender. Based on culture- and gender-based differences in interdependence of self-construals (Cross & Madson, 1997; Markus & Nurius, 1986), I hypothesize that Taiwanese students and American women would exhibit stronger association of age stereotypes to future self-views (i.e., internalization) than American men (hypothesis 4). Taiwanese and American women were found to have among the strongest internalization, but, unexpectedly, American men exhibited equal internalization and Taiwanese men exhibited the weakest internalization. A fifth hypothesis predicting that age integration (i.e., contact with both kin and non-kin older people) moderates the association of contact frequency with age stereotypes was unable to be tested due to an unbalanced response distribution on the relevant variable. Results of this dissertation reinforce the relevance of age stereotypes for future self-views among young adults and speak to the appropriateness of tailoring ageism-focused programs, policies, trainings or educational efforts to the individual or the cultural context.
-
1929. [Article] Constraints to urban park visitation: Conceptual connections and spatial attributes for traditionally well-served and underserved residents
Connecting with nature is associated with social, physical, and emotional benefits such as stress relief, improved physical health, and lower crime. Parks and other natural areas offer spaces in which ...Citation Citation
- Title:
- Constraints to urban park visitation: Conceptual connections and spatial attributes for traditionally well-served and underserved residents
- Author:
- Rushing, Jaclyn R.
Connecting with nature is associated with social, physical, and emotional benefits such as stress relief, improved physical health, and lower crime. Parks and other natural areas offer spaces in which to connect with nature and reap these and other benefits (e.g., family bonding, social events, learning). Despite increasing populations of racial and ethnic minorities in the United States of America, these groups are underrepresented in many outdoor recreation activities and in visitation to many parks and other protected areas. This underrepresentation and other attributes of park visitation can be partially explained through the theoretical lens of constraints to recreation. Constraints are factors that limit participation, affect leisure preferences, and / or reduce enjoyment and satisfaction with recreation experiences. Examples of constraints include inability to afford park fees, fear of crime in parks, and lack of available leisure time. This thesis contains two standalone articles focusing on resident constraints to visiting urban parks and other natural areas in the Portland, Oregon (USA) metropolitan region. These articles examine: (a) the most common constraints to visiting these parks and natural areas, and whether these constraints vary between traditionally well-served (i.e., white majority residents) and underserved (i.e., ethnic and racial minorities) populations; (b) relationships among constraints, park visitation, and place attachment for both of these groups of residents; and (c) how constraints groups, different types of constraints, and resident characteristics (e.g., minorities) are distributed spatially across this metropolitan region. Data were obtained from mail and online questionnaires completed by two samples of residents in Clackamas, Multnomah, and Washington counties: (a) a proportionate random sample of residents mostly targeting the following groups: African Americans / Blacks, American Indians, Asians, Hispanics / Latinos, Middle Eastern peoples, and Slavic / Eastern European peoples (i.e., probability sample); and (b) a convenience sample of Opt-In panel members (i.e., nonprobability sample). Questionnaires were completed by a total of 3,328 residents across these samples, and the data were weighted by the most recent Census based on county, age, sex (male, female), and education to be representative of adult residents in this region. Race and other demographics were consistent with the Census after weighting. Results of the first article showed that the primary constraints to visiting parks and natural areas in this urban region were being too busy to visit, limited knowledge about Metro parks, and lack of access to these places (Metro parks are managed by Metro, which is the main regional government for Clackamas, Multnomah, and Washington counties). There were no differences in these constraints and most other constraints between traditionally underserved and well-served populations. Traditionally underserved residents, however, were significantly more constrained than the well-served residents were by race and cultural issues at parks, as well as lack of facilities and services at Metro parks. Traditionally well-served residents visited all parks and natural areas in the region significantly more often than did the underserved residents, but there were no differences in visitation to Metro parks or their favorite park. There were also no differences between the two groups in their attachment to their favorite park. Constraints and visitation explained 15% of the variance in attachment for well-served residents and 38% for underserved residents, and constraints explained 4% of the variance in visitation for well-served residents and 26% for underserved residents. The strongest negative predictor of attachment for well-served residents was Metro parks are not the best places, followed by limited access to these places and disinterest in visiting parks and natural areas. The strongest positive predictor for well-served resident attachment was frequency of visitation, followed by race and cultural issues at Metro parks, and lack of facilities and services in these areas. For underserved residents, the strongest negative predictor of attachment was costs followed by Metro parks are not the best places and limited knowledge about these places. Positive predictors of attachment for these residents included frequency of visitation and lack of facilities and services at Metro parks. The only predictor of visitation to their favorite park for well-served residents was fear of visiting other areas (positive relationship), whereas visitation for underserved residents was negatively associated with limited access to Metro parks and positively associated with costs of visiting other areas. The second article used a Geographic Information System (GIS) and hot spot analysis of the survey data to determine any spatial patterns in constraints groups, different types of constraints, and resident characteristics (e.g., minorities). Results revealed two major trends: (a) in the northeast area of the region, there is a clustering of minority residents overlapping with the most constrained hot spots and these residents were most affected by constraints associated with health and lack of recreation partners; and (b) residents in the southwest area of the region were most affected by constraints associated with limited knowledge and access to parks. Specific implications of these results for both management and research are discussed in this thesis. In general, however, these results may inform local agency objectives associated with reaching and engaging various populations, including ethnic and racial minorities. These findings also contribute to the literature by exploring relationships among constraints, park visitation, and attachment between traditionally well-served and underserved populations, and also by applying a GIS analysis of survey data to understand spatial aspects of constraints for each of these populations.
-
1930. [Article] Optimizing map projection selection for world maps and web maps
The selection process for map projections is a mystery to many mapmakers and GIS users. Map projections ought to be selected based on the map’s geographic extent and the required distortion properties, ...Citation Citation
- Title:
- Optimizing map projection selection for world maps and web maps
- Author:
- Šavrič, Bojan
The selection process for map projections is a mystery to many mapmakers and GIS users. Map projections ought to be selected based on the map’s geographic extent and the required distortion properties, with the goal of minimizing the distortion of the mapped area. Despite some available selection guidelines, the selection of map projections is not yet automated. Automated selection would help mapmakers and GIS users to better select a projection for their map. The overall goal of this dissertation is to take a step towards this automation and explore user preferences with an objective to provide additional criteria for selecting world map projections. An additional goal is to optimize automatic map projection selection for web maps. The results presented in this work are mathematical models (new map projections for world maps, polynomial equations for selecting standard parallels) and new selection criteria for world maps. They improve our knowledge about map projection selection for world maps and web maps. As a result of the research presented in this doctoral dissertation, we know more about the map projection preferences of map-readers and have improved techniques for adapting map projections for scalable web maps and GIS software. Altogether, four concrete research questions were addressed. The first research question explores user preferences for world map projections. Many small-scale map projections exist and they have different shapes and distortion characteristics. World map projections are mainly chosen based on their distortion properties and the personal preferences of cartographers. Very little is known about the map projection preferences of map-readers; only two studies have addressed this question so far. This dissertation presents a user study among map-readers and trained cartographers that tests their preferences for world map projections. The paired comparison test of nine commonly used map projections reveals that the map-readers in our study prefer the Robinson and Plate Carrée projections, followed by the Winkel Tripel, Eckert IV, and Mollweide projections. The Mercator and Wagner VII projections come in sixth and seventh place, and the least preferred are two interrupted projections, the interrupted Mollweide and the interrupted Goode Homolosine. Separate binominal tests indicate that map-readers involved in the study seem to like projections with straight rather than curved parallels, and meridians with elliptical rather than sinusoidal shapes. The results indicate that map-readers prefer projections that represent poles as lines to projections that show poles as protruding edges, but there is no clear preference for pole lines in general. The trained cartographers involved in this study have similar preferences, but they prefer pole lines to represent the poles, and they select the Plate Carrée and Mercator projections less frequently than the other participants. The second research question introduces the polynomial equations for the Natural Earth II projection and tests user preferences for its graticule characteristics. The Natural Earth II projection is a new compromise pseudocylindrical projection for world maps. It has a unique shape compared to most other pseudocylindrical projections. At high latitudes, the meridians bend steeply toward short pole lines resulting in a map with highly rounded corners that resembles an elongated globe. Its distortion properties are similar to most other established world map projections. The projection equation consists of simple polynomials. A user study evaluated whether map-readers prefer Natural Earth II to similar compromise projections. The 355 participating general map- readers rated the Natural Earth II projection lower than the Robinson and Natural Earth projections, but higher than the Wagner VI, Kavrayskiy VII, and Wagner II projections. The third question examines how Wagner's transformation method can be used for improving map projections for scalable web maps, and its integration into the adaptive composite map projections schema. The adaptive composite map projections schema, invented by Bernhard Jenny, changes the projection to the geographic area shown on a map. It is meant as a replacement for the commonly used web Mercator projection, which grossly distorts areas when representing the entire world. The original equal-area version of the adaptive composite map projections schema uses the Lambert azimuthal projection for regional maps, and three alternative projections for world maps. In this dissertation, it is explored how the adaptive composite map projections schema can include a variety of other equal-area projections when the transformation between the Lambert azimuthal and the world projections uses Wagner's method. In order to select the most suitable pseudocylindrical projection, the distortion characteristics of a pseudocylindrical projection family were analyzed, and a user study among experts in the area of map projections was carried out. Based on the results of the distortion analysis and the user study, a new pseudocylindrical projection is recommended for extending the adaptive composite map projections schema. The new projection is equal-area throughout the transformation to the Lambert azimuthal projection, has better distortion characteristics than small-scale projections currently included in the original adaptive composite map projections schema, and aligns with map-readers' preferences for world map projections. The last research question explores how the selection of the standard parallels of conic projections can be automated. Conic map projections are appropriate for mapping regions at medium and large scales with east-west extents at intermediate latitudes. Conic projections are appropriate for these cases because they show the mapped area with less distortion than other projections. In order to minimize the distortion of the mapped area, the two standard parallels of conic projections need to be selected carefully. Rules of thumb exist for placing the standard parallels based on the width-to- height ratio of the map. These rules of thumb are simple to apply, but do not result in maps with minimum distortion. There also exist more sophisticated methods that determine standard parallels such that distortion in the mapped area is minimized. These methods are computationally expensive and cannot be used for real-time web mapping and GIS applications where the projection is adjusted automatically to the displayed area. This article presents a polynomial model that quickly provides the standard parallels for the three most common conic map projections: the Albers equal- area, the Lambert conformal, and the equidistant conic projection. The model defines the standard parallels with polynomial expressions based on the spatial extent of the mapped area. The spatial extent is defined by the length of the mapped central meridian segment, the central latitude of the displayed area, and the width-to-height ratio of the map. The polynomial model was derived from 3825 maps--each with a different spatial extent and computationally determined standard parallels that minimize the mean scale distortion index. The resulting model is computationally simple and can be used for the automatic selection of the standard parallels of conic map projections in GIS software and web mapping applications.