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• 28731. [Article] The electronic instrumentation for atmospheric laser propagation studies

  The use of laser radiation in atmospheric communication systems is revealing new forms of signal degradation not previously encountered with lower frequency transmitting sources. The coherence and directivity ...

  Citation × Citation Citation Abstract Copy Title: The electronic instrumentation for atmospheric laser propagation studies Author: Brown, Clyde Manford Year: 1968 The use of laser radiation in atmospheric communication systems is revealing new forms of signal degradation not previously encountered with lower frequency transmitting sources. The coherence and directivity of the laser which is responsible for its increased signal capacity is degraded by the effect of atmospheric distortion. Random fluctuations in the index of refraction (turbulence), Rayleigh scattering, aerosol scattering and other atmospheric effects create fluctuations (boiling, breathing, dancing, attenuation, transit-time dispersion, etc.) within the beam cross section, which when received produce random fluctuations in the receiver output signal. The two systems which are described, are designed to investigate the effect of atmospheric distortions on the amplitude and phase (or transit time) of the laser beam. The Scintillation System was designed for real-time determination of amplitude scintillation statistics. The system will be incorporated into a multi-wavelength, multi-range experiment for comparison of theoretical and experimental meteorological and optical data. The system includes a laser transmitter, an atmospheric path over which the beam is allowed to diverge to a three-foot cross section, a pair of photomultipliers with variable spacing and small sampling apertures, an analog "scintillation computer," and a recording device. The scintillation computer is a real time, special purpose, analog computer designed to compute the variance and covariance of log amplitude, the probability distribution of log amplitude, and the frequency spectrum of the amplitude scintillation. The system permits the recording of these data as a function of transmitter and receiver aperture, and time. The Short Pulse Distortion System is designed to detect pulse distortion due to transit-time dispersion of the laser beam. The system includes a mode-locked laser (i.e., the optical short pulse generator), a large transmitting aperture (a Cassegrainian telescope), the atmospheric path, a wideband receiver, a sampling oscilloscope, the "Pulse Distortion Analyzer," and a high-quality tape recorder. The Pulse Distortion Analyzer is designed to compare the transmitted pulses to recorded reference pulses and to detect differential area due to time dispersion. The analyzer includes a novel, feed forward, automatic gain control circuit which utilizes a linear photo detector and an analog divider to smooth a 300Hz signal with a 100 microsecond response time. This is necessary to smooth out the signal amplitude fluctuations due to atmospheric turbulence effects. Both systems have been set up and tested on a one-mile path between the Oregon Graduate Center and Skyline Drive in Portland Oregon, using a 6328Å He-Ne Laser. The ultimate use of the scintillation computer will be in a multi-wave-length experiment conducted for the Office of Naval Research, and will utilize a uniform, meteorologically instrumented path for comparison with theoretical predictions. The Pulse Distortion System will be incorporated into a joint experiment with the Electro-optic Organization of Sylvania Electronic Systems, Inc., Mountain View, California, to be conducted over a seven-mile path. Title: The electronic instrumentation for atmospheric laser propagation studies Author: Brown, Clyde Manford Year: 1968 The use of laser radiation in atmospheric communication systems is revealing new forms of signal degradation not previously encountered with lower frequency transmitting sources. The coherence and directivity of the laser which is responsible for its increased signal capacity is degraded by the effect of atmospheric distortion. Random fluctuations in the index of refraction (turbulence), Rayleigh scattering, aerosol scattering and other atmospheric effects create fluctuations (boiling, breathing, dancing, attenuation, transit-time dispersion, etc.) within the beam cross section, which when received produce random fluctuations in the receiver output signal. The two systems which are described, are designed to investigate the effect of atmospheric distortions on the amplitude and phase (or transit time) of the laser beam. The Scintillation System was designed for real-time determination of amplitude scintillation statistics. The system will be incorporated into a multi-wavelength, multi-range experiment for comparison of theoretical and experimental meteorological and optical data. The system includes a laser transmitter, an atmospheric path over which the beam is allowed to diverge to a three-foot cross section, a pair of photomultipliers with variable spacing and small sampling apertures, an analog "scintillation computer," and a recording device. The scintillation computer is a real time, special purpose, analog computer designed to compute the variance and covariance of log amplitude, the probability distribution of log amplitude, and the frequency spectrum of the amplitude scintillation. The system permits the recording of these data as a function of transmitter and receiver aperture, and time. The Short Pulse Distortion System is designed to detect pulse distortion due to transit-time dispersion of the laser beam. The system includes a mode-locked laser (i.e., the optical short pulse generator), a large transmitting aperture (a Cassegrainian telescope), the atmospheric path, a wideband receiver, a sampling oscilloscope, the "Pulse Distortion Analyzer," and a high-quality tape recorder. The Pulse Distortion Analyzer is designed to compare the transmitted pulses to recorded reference pulses and to detect differential area due to time dispersion. The analyzer includes a novel, feed forward, automatic gain control circuit which utilizes a linear photo detector and an analog divider to smooth a 300Hz signal with a 100 microsecond response time. This is necessary to smooth out the signal amplitude fluctuations due to atmospheric turbulence effects. Both systems have been set up and tested on a one-mile path between the Oregon Graduate Center and Skyline Drive in Portland Oregon, using a 6328Å He-Ne Laser. The ultimate use of the scintillation computer will be in a multi-wave-length experiment conducted for the Office of Naval Research, and will utilize a uniform, meteorologically instrumented path for comparison with theoretical predictions. The Pulse Distortion System will be incorporated into a joint experiment with the Electro-optic Organization of Sylvania Electronic Systems, Inc., Mountain View, California, to be conducted over a seven-mile path. Close

• 28732. [Article] Site Fidelity, Associations and Long-Term Bonds of Short-Finned Pilot Whales off the Island of Hawai`i

  Short-finned pilot whales (Globicephala macrorhynchus) are the most frequently sighted odontocete in a long-term study in Hawaiʹi (representing 23.8% of all odontocete sightings from directed research ...

  Citation × Citation Citation Abstract Copy Title: Site Fidelity, Associations and Long-Term Bonds of Short-Finned Pilot Whales off the Island of Hawai`i Author: Mahaffy, Sabre D. Year: 2012 Short-finned pilot whales (Globicephala macrorhynchus) are the most frequently sighted odontocete in a long-term study in Hawaiʹi (representing 23.8% of all odontocete sightings from directed research efforts), yet little has been published on this species in Hawaiian waters. Studies elsewhere have suggested that short-finned pilot whales travel in stable mixed-sex groups composed of strongly associated individuals; however temporal analyses of social structure are lacking. To examine site fidelity, association patterns and temporal relationships, I analyzed data from 267 directed research and opportunistic encounters of short-finned pilot whales off the island of Hawai`i from 2003 through 2007. Sightings occurred year-round. Analysis of sighting depths in relation to effort indicated short-finned pilot whales are strongly associated with the island slope, with no sightings in water >2,700m deep despite effort to ~5,000m. Using only good quality photos, I identified 448 distinctive individuals; of these, 305 (68.1%) were seen more than once and 250 (55.8%) were seen in >1 year. Sighting histories varied from 1-29 sightings per individual (median=3) over the course of the study, suggesting only some individuals exhibit high site-fidelity. Degree of residency was assessed using multi-year site fidelity to the study area; individuals seen ≥5 times in ≥3 years were considered core residents (154 individuals) while individuals who fell below these criteria but that were seen more than once were termed residents (150 individuals) and those seen on a single occasion were termed visitors (142 individuals). Only 71.9% of the whales were linked by association into a single social network, suggesting the possibility of multiple populations using the study area. Individuals demonstrated preferential associations and community division was strongly supported by average-linkage hierarchical cluster analysis of the association data. Nine longitudinally-stable social units composed of key individuals (seen together ≥8 times in ≥4 years) and their constant companions (seen together ≥5 times in ≥3 years) were identified (unit membership 5-16, median=10.5; mean unit association index: 0.62-0.90). Qualitative assignment of age and sex classes to unit members indicated some segregation between adult males and female/calf pairs may occur. Temporal analysis using standardized lagged association rates of individuals grouped in the same encounter produced a best-fit model where dyads gradually disassociated over time while individuals grouped in the same day produced a model where dyads remained in association, suggesting companions not documented during an encounter are likely still present in the study area. Differential patterns of residency and site fidelity were unexpected and may be indicative of multiple populations around the main Hawaiian Islands. Additionally, the presence of a core resident population demonstrating strong, long-term site-fidelity and associations off the island of Hawaiʹi may warrant special management considerations. Evidence of fisheries-related injuries in addition to anthropogenic threats such as high levels of commercial and recreational vessel traffic, targeted tourist activities, and commercial and sports troll fisheries indicate that additional research is needed to evaluate potential threats to this island-associated population. Title: Site Fidelity, Associations and Long-Term Bonds of Short-Finned Pilot Whales off the Island of Hawai`i Author: Mahaffy, Sabre D. Year: 2012 Short-finned pilot whales (Globicephala macrorhynchus) are the most frequently sighted odontocete in a long-term study in Hawaiʹi (representing 23.8% of all odontocete sightings from directed research efforts), yet little has been published on this species in Hawaiian waters. Studies elsewhere have suggested that short-finned pilot whales travel in stable mixed-sex groups composed of strongly associated individuals; however temporal analyses of social structure are lacking. To examine site fidelity, association patterns and temporal relationships, I analyzed data from 267 directed research and opportunistic encounters of short-finned pilot whales off the island of Hawai`i from 2003 through 2007. Sightings occurred year-round. Analysis of sighting depths in relation to effort indicated short-finned pilot whales are strongly associated with the island slope, with no sightings in water >2,700m deep despite effort to ~5,000m. Using only good quality photos, I identified 448 distinctive individuals; of these, 305 (68.1%) were seen more than once and 250 (55.8%) were seen in >1 year. Sighting histories varied from 1-29 sightings per individual (median=3) over the course of the study, suggesting only some individuals exhibit high site-fidelity. Degree of residency was assessed using multi-year site fidelity to the study area; individuals seen ≥5 times in ≥3 years were considered core residents (154 individuals) while individuals who fell below these criteria but that were seen more than once were termed residents (150 individuals) and those seen on a single occasion were termed visitors (142 individuals). Only 71.9% of the whales were linked by association into a single social network, suggesting the possibility of multiple populations using the study area. Individuals demonstrated preferential associations and community division was strongly supported by average-linkage hierarchical cluster analysis of the association data. Nine longitudinally-stable social units composed of key individuals (seen together ≥8 times in ≥4 years) and their constant companions (seen together ≥5 times in ≥3 years) were identified (unit membership 5-16, median=10.5; mean unit association index: 0.62-0.90). Qualitative assignment of age and sex classes to unit members indicated some segregation between adult males and female/calf pairs may occur. Temporal analysis using standardized lagged association rates of individuals grouped in the same encounter produced a best-fit model where dyads gradually disassociated over time while individuals grouped in the same day produced a model where dyads remained in association, suggesting companions not documented during an encounter are likely still present in the study area. Differential patterns of residency and site fidelity were unexpected and may be indicative of multiple populations around the main Hawaiian Islands. Additionally, the presence of a core resident population demonstrating strong, long-term site-fidelity and associations off the island of Hawaiʹi may warrant special management considerations. Evidence of fisheries-related injuries in addition to anthropogenic threats such as high levels of commercial and recreational vessel traffic, targeted tourist activities, and commercial and sports troll fisheries indicate that additional research is needed to evaluate potential threats to this island-associated population. Close

• 28733. [Article] Oxygen Demand Trends, Land Cover Change, and Water Quality Management for an Urbanizing Oregon Watershed

  In-stream aquatic habitat depends on adequate levels of dissolved oxygen. Human alteration of the landscape has an extensive influence on the biogeochemical processes that drive oxygen cycling in streams. ...

  Citation × Citation Citation Abstract Copy Title: Oxygen Demand Trends, Land Cover Change, and Water Quality Management for an Urbanizing Oregon Watershed Author: Boeder, Michael Karl Year: 2006 In-stream aquatic habitat depends on adequate levels of dissolved oxygen. Human alteration of the landscape has an extensive influence on the biogeochemical processes that drive oxygen cycling in streams. Historic datasets allow researchers to track trends in chemical parameters concomitant with urbanization, while land cover change analysis allows researchers to identify linkages between water quality trends and landscape change. Using the Seasonal Kendall's test, I examined water quality trends in oxygen demand variables during the mid-1990s to 2003, for twelve sites in the Rock Creek sub-watershed of the Tualatin River, northwest Oregon. Significant trends occurred in each parameter. Dissolved oxygen (DO (%sat)) increased at five sites. Chemical oxygen demand (COD) decreased at seven sites. Total Kjeldahl nitrogen (TKN) decreased at five sites and increased at one site. Ammonium (NH3-N) decreased at one site and increased at one site. Multiple linear regression indicates that nitrogenous oxygen demand accounts for a significant amount of variance in COD at ten of the twelve sites (adjusted R2values from 0.14 to 0.73). Aerial photo interpretation revealed significant land cover change in agricultural land cover (-8% for the entire basin area) and residential land cover (+10% for the entire basin area). Correlation results between seasonal oxygen demand data and land cover values at multiple scales indicated that: (I) forest cover negatively influences COD at the full sub-basin scale and positively influences NH3-N at local scales, (2) residential land cover positively influences DO (%sat) values at local scales, (3) agricultural land cover does not influence oxygen demand at any land cover assessment scale, ( 4) local topography negatively influences TKN and NH3-N, and (5) urban runoff management infrastructure correlates positively with COD. Study results indicate that, with the exception of forested land, local scale land cover and landscape variables dominate influence on oxygen demand in the Rock Creek basin. Since DO conditions have improved in these streams, watershed management efforts should emphasize local influences in order to continue to maintain stream health. Title: Oxygen Demand Trends, Land Cover Change, and Water Quality Management for an Urbanizing Oregon Watershed Author: Boeder, Michael Karl Year: 2006 In-stream aquatic habitat depends on adequate levels of dissolved oxygen. Human alteration of the landscape has an extensive influence on the biogeochemical processes that drive oxygen cycling in streams. Historic datasets allow researchers to track trends in chemical parameters concomitant with urbanization, while land cover change analysis allows researchers to identify linkages between water quality trends and landscape change. Using the Seasonal Kendall's test, I examined water quality trends in oxygen demand variables during the mid-1990s to 2003, for twelve sites in the Rock Creek sub-watershed of the Tualatin River, northwest Oregon. Significant trends occurred in each parameter. Dissolved oxygen (DO (%sat)) increased at five sites. Chemical oxygen demand (COD) decreased at seven sites. Total Kjeldahl nitrogen (TKN) decreased at five sites and increased at one site. Ammonium (NH3-N) decreased at one site and increased at one site. Multiple linear regression indicates that nitrogenous oxygen demand accounts for a significant amount of variance in COD at ten of the twelve sites (adjusted R2values from 0.14 to 0.73). Aerial photo interpretation revealed significant land cover change in agricultural land cover (-8% for the entire basin area) and residential land cover (+10% for the entire basin area). Correlation results between seasonal oxygen demand data and land cover values at multiple scales indicated that: (I) forest cover negatively influences COD at the full sub-basin scale and positively influences NH3-N at local scales, (2) residential land cover positively influences DO (%sat) values at local scales, (3) agricultural land cover does not influence oxygen demand at any land cover assessment scale, ( 4) local topography negatively influences TKN and NH3-N, and (5) urban runoff management infrastructure correlates positively with COD. Study results indicate that, with the exception of forested land, local scale land cover and landscape variables dominate influence on oxygen demand in the Rock Creek basin. Since DO conditions have improved in these streams, watershed management efforts should emphasize local influences in order to continue to maintain stream health. Close

• 28734. [Article] Riparian Shade Assessment and Restoration Priorities Analysis in the Damascus Urban Growth Boundary Expansion Area

  An important component of progressive urban planning is the protection and restoration of riparian environments, particularly in the Pacific Northwest where increasing stream temperatures threaten the ...

  Citation × Citation Citation Abstract Copy Title: Riparian Shade Assessment and Restoration Priorities Analysis in the Damascus Urban Growth Boundary Expansion Area Author: Leferink, Robin K. Year: 2007 An important component of progressive urban planning is the protection and restoration of riparian environments, particularly in the Pacific Northwest where increasing stream temperatures threaten the survival of endangered salmonids and other cold-water biota. Restoration projects are often led by watershed councils or other grassroots organizations with limited resources, and it is essential that these groups have an efficient and effective approach to determine priority areas where their efforts can be directed to achieve the greatest ecological benefit. The purpose of this project was to quantify existing riparian shade levels and identify priority reaches for shade restoration on Clackamas River basin streams in the Damascus area expansion of the Portland, Oregon urban growth boundary. Additionally, potential errors in the Metro Regional Land Information System (RLIS) Lite geographic information system (GIS) coverage of the area’s streams were identified and corrected where possible. Riparian shade levels were quantified through interpretation of digital aerial photographs using GIS. At the start of the shade analysis six 50 m reaches in the study area were surveyed using a spherical densiometer to calibrate the aerial photo interpretation. Following the analysis, the method accuracy was assessed by comparing GIS-derived shade classes with field data from 25 sites in the study area that were surveyed in 2003. Stream reaches were identified and prioritized for restoration based on riparian shade level, presence or absence of late-summer flow (as determined through field investigations), and GISevaluated stream aspect (i.e. the direction of stream flow). Generally, the headwaters were found to have less shade than the downstream areas and many of the headwater reaches were identified as the highest restoration priority. Of the 60.5 km of streams assessed in the riparian shade analysis, 24.7 km were identified as potential restoration reaches based on shade levels and late-summer flow conditions. These 24.7 km were further broken into five priority ranks, with 4.1 km of stream reaches assigned to the highest shade restoration priority class. Potential errors in the GIS stream coverage were identified in conjunction with the riparian shade assessment. Where possible, these errors were corrected based on the aerial photographs. Although in many cases access was limited, a total of 18 site visits were made to verify stream locations. The results of this watershed-scale restoration priorities analysis are being used by Clackamas River Basin Council and others to guide restoration planning in the new urban area. While focusing on the high priority stream reaches identified, restoration managers will also need to consider reach-scale factors including land use plans, riparian continuity, parcel size, and landowner cooperation in the final selection of restoration sites. The GIS stream layer corrections were provided to Metro and to the City of Damascus for use in their 2007 natural resource inventory. Title: Riparian Shade Assessment and Restoration Priorities Analysis in the Damascus Urban Growth Boundary Expansion Area Author: Leferink, Robin K. Year: 2007 An important component of progressive urban planning is the protection and restoration of riparian environments, particularly in the Pacific Northwest where increasing stream temperatures threaten the survival of endangered salmonids and other cold-water biota. Restoration projects are often led by watershed councils or other grassroots organizations with limited resources, and it is essential that these groups have an efficient and effective approach to determine priority areas where their efforts can be directed to achieve the greatest ecological benefit. The purpose of this project was to quantify existing riparian shade levels and identify priority reaches for shade restoration on Clackamas River basin streams in the Damascus area expansion of the Portland, Oregon urban growth boundary. Additionally, potential errors in the Metro Regional Land Information System (RLIS) Lite geographic information system (GIS) coverage of the area’s streams were identified and corrected where possible. Riparian shade levels were quantified through interpretation of digital aerial photographs using GIS. At the start of the shade analysis six 50 m reaches in the study area were surveyed using a spherical densiometer to calibrate the aerial photo interpretation. Following the analysis, the method accuracy was assessed by comparing GIS-derived shade classes with field data from 25 sites in the study area that were surveyed in 2003. Stream reaches were identified and prioritized for restoration based on riparian shade level, presence or absence of late-summer flow (as determined through field investigations), and GISevaluated stream aspect (i.e. the direction of stream flow). Generally, the headwaters were found to have less shade than the downstream areas and many of the headwater reaches were identified as the highest restoration priority. Of the 60.5 km of streams assessed in the riparian shade analysis, 24.7 km were identified as potential restoration reaches based on shade levels and late-summer flow conditions. These 24.7 km were further broken into five priority ranks, with 4.1 km of stream reaches assigned to the highest shade restoration priority class. Potential errors in the GIS stream coverage were identified in conjunction with the riparian shade assessment. Where possible, these errors were corrected based on the aerial photographs. Although in many cases access was limited, a total of 18 site visits were made to verify stream locations. The results of this watershed-scale restoration priorities analysis are being used by Clackamas River Basin Council and others to guide restoration planning in the new urban area. While focusing on the high priority stream reaches identified, restoration managers will also need to consider reach-scale factors including land use plans, riparian continuity, parcel size, and landowner cooperation in the final selection of restoration sites. The GIS stream layer corrections were provided to Metro and to the City of Damascus for use in their 2007 natural resource inventory. Close

• 28735. [Article] Seasonal and Sex Differences in the Effects of Melatonin on Brain Arginine Vasotocin in Green Treefrogs (Hyla cinerea): Relationship to Melatonin Receptor 1a

  Critical life history events such as breeding, migration and hibernation must take place in the correct environmental context to minimize deleterious consequences on survival and reproductive fitness. ...

  Citation × Citation Citation Abstract Copy Title: Seasonal and Sex Differences in the Effects of Melatonin on Brain Arginine Vasotocin in Green Treefrogs (Hyla cinerea): Relationship to Melatonin Receptor 1a Author: Howard, Christina Marie Year: 2014 Critical life history events such as breeding, migration and hibernation must take place in the correct environmental context to minimize deleterious consequences on survival and reproductive fitness. Neuroendocrine mechanisms synchronizing internal physiological states with extrinsic environmental cues are vital to timing life history events appropriately. Secretion of the pineal hormone melatonin is sensitive to light and temperature cues, which provides a physiological indicator of time of day and time of year for organisms. Melatonin influences seasonal reproduction in a variety of vertebrates, likely by altering the synthesis and/or release of reproductive neuropeptides in the brain. The neuropeptides arginine vasotocin and its mammalian homologue, arginine vasopressin, are well-known modulators of reproductive and sociosexual behavior across vertebrate taxa, and are likely targets of melatonin in the context of seasonal reproduction. There is extensive evidence that vasotocin/vasopressin innervation in the brain is subject to seasonal variation, and that this variation is frequently sexually dimorphic. However, evidence that melatonin directly modulates this important neuropeptide system is lacking. Melatonin receptor 1a (MT1 in mammals) may be responsible for mediating melatonin's influence on brain vasotocin, as it is known to regulate seasonal reproduction in a variety of vertebrates. In the present study, I asked whether melatonin influences brain vasotocin in male green treefrogs (Hyla cinerea), and compared the distribution of melatonin receptor 1a in the brain of green treefrogs between sexes and seasons. Adult male and female green treefrogs were collected from field sites in Louisiana during the summer breeding season. Summer animals were acclimated to lab conditions for 3 weeks, then euthanized and their brains collected. Winter animals were maintained in the lab for four months under incrementally changing photo-, thermo-, and hygroperiod regimes that mimicked the transition to winter in their natural habitat, followed by euthanasia and brain collection. A subset of winter males (Experiment 1) were implanted with melatonin-filled or blank silastic capsules for a period of one month prior to euthanasia and brain collection. Brains of these males were processed for vasotocin immunohistochemistry. I quantified AVT-ir cell number in Experiment 1 males in the nucleus accumbens (NAcc), amygdala and caudal striatum (AMG), preoptic area (POA), suprachaismatic nucleus (SCN), and ventral hypothalamus (VH). Melatonin did not influence brain vasotocin-ir cell number in any brain region. Brains from untreated summer and winter males and females were collected and processed for MT1 immunohistochemistry. MT1-ir cells were quantified in the NAcc, striatum (STR), AMG, POA, SCN, and VH. In all regions quantified, reproductively active males had significantly more MT1-ir cells than nonreproductive males. Within the summer breeding season, males had significantly more MT1-ir cells in the NAcc than did reproductively active females. In all other regions there was no significant difference in MT1-ir cell number between reproductively active males and females. Collectively, these data suggest that melatonin modulates vasotocin via MT1. These findings assist in elucidating the neuroendocrine mechanisms by which vertebrates integrate seasonal cues with physiology to correctly time critical life history events. Title: Seasonal and Sex Differences in the Effects of Melatonin on Brain Arginine Vasotocin in Green Treefrogs (Hyla cinerea): Relationship to Melatonin Receptor 1a Author: Howard, Christina Marie Year: 2014 Critical life history events such as breeding, migration and hibernation must take place in the correct environmental context to minimize deleterious consequences on survival and reproductive fitness. Neuroendocrine mechanisms synchronizing internal physiological states with extrinsic environmental cues are vital to timing life history events appropriately. Secretion of the pineal hormone melatonin is sensitive to light and temperature cues, which provides a physiological indicator of time of day and time of year for organisms. Melatonin influences seasonal reproduction in a variety of vertebrates, likely by altering the synthesis and/or release of reproductive neuropeptides in the brain. The neuropeptides arginine vasotocin and its mammalian homologue, arginine vasopressin, are well-known modulators of reproductive and sociosexual behavior across vertebrate taxa, and are likely targets of melatonin in the context of seasonal reproduction. There is extensive evidence that vasotocin/vasopressin innervation in the brain is subject to seasonal variation, and that this variation is frequently sexually dimorphic. However, evidence that melatonin directly modulates this important neuropeptide system is lacking. Melatonin receptor 1a (MT1 in mammals) may be responsible for mediating melatonin's influence on brain vasotocin, as it is known to regulate seasonal reproduction in a variety of vertebrates. In the present study, I asked whether melatonin influences brain vasotocin in male green treefrogs (Hyla cinerea), and compared the distribution of melatonin receptor 1a in the brain of green treefrogs between sexes and seasons. Adult male and female green treefrogs were collected from field sites in Louisiana during the summer breeding season. Summer animals were acclimated to lab conditions for 3 weeks, then euthanized and their brains collected. Winter animals were maintained in the lab for four months under incrementally changing photo-, thermo-, and hygroperiod regimes that mimicked the transition to winter in their natural habitat, followed by euthanasia and brain collection. A subset of winter males (Experiment 1) were implanted with melatonin-filled or blank silastic capsules for a period of one month prior to euthanasia and brain collection. Brains of these males were processed for vasotocin immunohistochemistry. I quantified AVT-ir cell number in Experiment 1 males in the nucleus accumbens (NAcc), amygdala and caudal striatum (AMG), preoptic area (POA), suprachaismatic nucleus (SCN), and ventral hypothalamus (VH). Melatonin did not influence brain vasotocin-ir cell number in any brain region. Brains from untreated summer and winter males and females were collected and processed for MT1 immunohistochemistry. MT1-ir cells were quantified in the NAcc, striatum (STR), AMG, POA, SCN, and VH. In all regions quantified, reproductively active males had significantly more MT1-ir cells than nonreproductive males. Within the summer breeding season, males had significantly more MT1-ir cells in the NAcc than did reproductively active females. In all other regions there was no significant difference in MT1-ir cell number between reproductively active males and females. Collectively, these data suggest that melatonin modulates vasotocin via MT1. These findings assist in elucidating the neuroendocrine mechanisms by which vertebrates integrate seasonal cues with physiology to correctly time critical life history events. Close

• 28736. [Article] Teacher Learning: Documentation, Collaboration, and Reflection

  Inspired by the Municipal preprimary schools of Reggio Emilia, Italy, two art studio teachers and a researcher have explored experiences and meaning in the atelier. When studio teachers document children's ...

  Citation × Citation Citation Abstract Copy Title: Teacher Learning: Documentation, Collaboration, and Reflection Author: Parnell, William A. Year: 2005 Inspired by the Municipal preprimary schools of Reggio Emilia, Italy, two art studio teachers and a researcher have explored experiences and meaning in the atelier. When studio teachers document children's thinking through digital photographs. transcribed audio tapes, quotations of a child's verbal thoughts, and copies of their work, an indescribable moment in teacher thinking interweaves with the child's learning, As teachers capture children's representations, investigate, interpret, and share their ideas with colleagues and community-an underlying question emerges. What are studio teachers' experiences o/teaching-learning in the atelier as they utilize documentation, collaboration, and reflection as a way to inform their practices? From this question, reader and researcher start a journey together into a six-month phenomenological study of studio teaching experiences. As a core member in the teaching team, the studio teacher resides in the atelier to bring teaching and learning together in a profound way, to bridge classroom experiences with representative arts, and to facilitate the community's learning about teaching-learning. The methods used to inform this study include observations, in-depth interviews, electronic journaling, description, photos, and interpretation of studio work. Overall, this study's methods inform the phenomenological research and construct an in-depth look at experiences in the artist's studio. The results of this research are retold through narratives focusing on experiences and meaning-making in the studios. Stories such as living with the cracked egg; isolation in the studio: gifts for others; rough stones polishing one another; and many others, utilize photographs to enhance meaning through picturesque artifacts. Essential themes, conclusions, and implications appear in the webbing of experiences and are explored in the final chapter. The themes include conceptual frameworks such as life eats entropy, serendipity and synergy and more. Conclusions are drawn and findings are made connecting studio experiences to participant voice, disequilibrium, listening, engaging, stepping back, and slowing time; demonstrating documentation as learning, revisiting, representation, and manageability; making meaning of collaboration as struggle, communication, and reconstruction; and reflecting back as purposeful and an act of teaching-learning. Overall, this research study exposes techniques, ideas, and wonderings from two studio teachers' and a researcher's experiences in the atelier. Title: Teacher Learning: Documentation, Collaboration, and Reflection Author: Parnell, William A. Year: 2005 Inspired by the Municipal preprimary schools of Reggio Emilia, Italy, two art studio teachers and a researcher have explored experiences and meaning in the atelier. When studio teachers document children's thinking through digital photographs. transcribed audio tapes, quotations of a child's verbal thoughts, and copies of their work, an indescribable moment in teacher thinking interweaves with the child's learning, As teachers capture children's representations, investigate, interpret, and share their ideas with colleagues and community-an underlying question emerges. What are studio teachers' experiences o/teaching-learning in the atelier as they utilize documentation, collaboration, and reflection as a way to inform their practices? From this question, reader and researcher start a journey together into a six-month phenomenological study of studio teaching experiences. As a core member in the teaching team, the studio teacher resides in the atelier to bring teaching and learning together in a profound way, to bridge classroom experiences with representative arts, and to facilitate the community's learning about teaching-learning. The methods used to inform this study include observations, in-depth interviews, electronic journaling, description, photos, and interpretation of studio work. Overall, this study's methods inform the phenomenological research and construct an in-depth look at experiences in the artist's studio. The results of this research are retold through narratives focusing on experiences and meaning-making in the studios. Stories such as living with the cracked egg; isolation in the studio: gifts for others; rough stones polishing one another; and many others, utilize photographs to enhance meaning through picturesque artifacts. Essential themes, conclusions, and implications appear in the webbing of experiences and are explored in the final chapter. The themes include conceptual frameworks such as life eats entropy, serendipity and synergy and more. Conclusions are drawn and findings are made connecting studio experiences to participant voice, disequilibrium, listening, engaging, stepping back, and slowing time; demonstrating documentation as learning, revisiting, representation, and manageability; making meaning of collaboration as struggle, communication, and reconstruction; and reflecting back as purposeful and an act of teaching-learning. Overall, this research study exposes techniques, ideas, and wonderings from two studio teachers' and a researcher's experiences in the atelier. Close

• 28737. [Article] Report of HURL Cruise KOK0510: Submersible Dives and Multibeam Mapping to Investigate Benthic Habitats of Tutuila, American Samoa

  Available also from http://dusk.geo.orst.edu/djl/samoa/hurl/KOK0510cruise_report.pdf

  Citation × Citation Citation Abstract Copy Title: Report of HURL Cruise KOK0510: Submersible Dives and Multibeam Mapping to Investigate Benthic Habitats of Tutuila, American Samoa Author: Wright, Dawn Available also from http://dusk.geo.orst.edu/djl/samoa/hurl/KOK0510cruise_report.pdf Title: Report of HURL Cruise KOK0510: Submersible Dives and Multibeam Mapping to Investigate Benthic Habitats of Tutuila, American Samoa Author: Wright, Dawn Available also from http://dusk.geo.orst.edu/djl/samoa/hurl/KOK0510cruise_report.pdf Close

• 28738. [Article] WAVE pilot study: Creation of education tools to promote proper body composition analysis and body image awareness

  Background: The Wave~Ripples for Change: Obesity Prevention in High-School Soccer Players research project is a 5-Y USDA funded project focused on building healthy nutrition, physical activity and life ...

  Citation × Citation Citation Abstract Copy Title: WAVE pilot study: Creation of education tools to promote proper body composition analysis and body image awareness Author: Skoog, Ingrid, Wong, Siew Sun, Chan, Lauren E. Background: The Wave~Ripples for Change: Obesity Prevention in High-School Soccer Players research project is a 5-Y USDA funded project focused on building healthy nutrition, physical activity and life skills for healthy weight maintenance. The intervention includes providing face-to-face sport nutrition, physical activity and life- skills lessons, assessments of body composition, physical activity, and nutrition, and on-line immersive learning to reinforce the lessons. Objective: Develop two lessons to educate youth soccer players (age=14-19y): 1) For males, the focus is body weight and composition, and factors related to building/retaining muscle mass to reduce risk of inappropriate diet and supplement use; 2) For females, the focus is body image and associated issues about body weight and performance to reduce the risk of body dissatisfaction and disordered eating. Method: Review the research literature and identify key body composition and body image issues unique to males and females, especially active high school youth. Then develop two different lessons that will encompass the needs of each gender utilizing photos, online capabilities and common misconceptions about food, exercise and body size. Results: Research shows that active males are more interested in gaining weight, specifically muscle mass, which increases the risk of using unhealthy diets and supplements promising increased in muscle mass. Active females are more interested in being thin and small stature, which can lead to disordered eating and body image issues. Two educational lessons were developed to address the different weight and body composition issues identified for each group. For the males, the lesson focuses on understanding body composition and how it is measured, the impact of body composition on health and performance, and factors that improve body composition, including appropriate diet and exercise recommendations. For the females, the lesson focuses on understanding body composition and image, and how inappropriate beliefs about body shape and size increases the risk of body dissatisfaction. Approaches to improve body image and satisfaction are presented and discussed. Conclusions: Lessons will be tested on the WAVE pilot study high school soccer players (n=26). Based on feedback from students, changes will be made to the lessons prior to program delivery to the larger intervention study beginning in fall 2015. Title: WAVE pilot study: Creation of education tools to promote proper body composition analysis and body image awareness Author: Skoog, Ingrid, Wong, Siew Sun, Chan, Lauren E. Background: The Wave~Ripples for Change: Obesity Prevention in High-School Soccer Players research project is a 5-Y USDA funded project focused on building healthy nutrition, physical activity and life skills for healthy weight maintenance. The intervention includes providing face-to-face sport nutrition, physical activity and life- skills lessons, assessments of body composition, physical activity, and nutrition, and on-line immersive learning to reinforce the lessons. Objective: Develop two lessons to educate youth soccer players (age=14-19y): 1) For males, the focus is body weight and composition, and factors related to building/retaining muscle mass to reduce risk of inappropriate diet and supplement use; 2) For females, the focus is body image and associated issues about body weight and performance to reduce the risk of body dissatisfaction and disordered eating. Method: Review the research literature and identify key body composition and body image issues unique to males and females, especially active high school youth. Then develop two different lessons that will encompass the needs of each gender utilizing photos, online capabilities and common misconceptions about food, exercise and body size. Results: Research shows that active males are more interested in gaining weight, specifically muscle mass, which increases the risk of using unhealthy diets and supplements promising increased in muscle mass. Active females are more interested in being thin and small stature, which can lead to disordered eating and body image issues. Two educational lessons were developed to address the different weight and body composition issues identified for each group. For the males, the lesson focuses on understanding body composition and how it is measured, the impact of body composition on health and performance, and factors that improve body composition, including appropriate diet and exercise recommendations. For the females, the lesson focuses on understanding body composition and image, and how inappropriate beliefs about body shape and size increases the risk of body dissatisfaction. Approaches to improve body image and satisfaction are presented and discussed. Conclusions: Lessons will be tested on the WAVE pilot study high school soccer players (n=26). Based on feedback from students, changes will be made to the lessons prior to program delivery to the larger intervention study beginning in fall 2015. Close

• 28739. [Article] Where Is Portland Made? The Complex Relationship between Social Media and Place in the Artisan Economy of Portland, Oregon (USA)

  Portland, Oregon (USA) has become known for an artisanal or ‘maker’ economy that relies on a resurgence of place specificity (Heying), primarily expressed and exported to a global audience in the notion ...

  Citation × Citation Citation Abstract Copy Title: Where Is Portland Made? The Complex Relationship between Social Media and Place in the Artisan Economy of Portland, Oregon (USA) Author: Marotta, Stephen, Cummings, Austin, Heying, Charles H. Year: 2016 Portland, Oregon (USA) has become known for an artisanal or ‘maker’ economy that relies on a resurgence of place specificity (Heying), primarily expressed and exported to a global audience in the notion of ‘Portland Made’ (Roy). Portland Made reveals a tension immanent in the notion of ‘place’: place is both here and not here, both real and imaginary. What emerges is a complicated picture of how place conceptually captures various intersections of materiality and mythology, aesthetics and economics. On the one hand, Portland Made represents the collective brand-identity used by Portland’s makers to signify a products’ material existence as handcrafted, place-embedded, and authentic. These characteristics lead to certain assumptions about the concept of ‘local’ (Marotta and Heying): what meaning does Portland Made convey, and how is such meaning distributed? On the other hand, the seemingly intentional embedding of place-specificity in objects meant for distribution far outside of Portland begs another type of question: how does Portland come to be discursively representative of these characteristics, and how are such representations distributed to global audiences? How does this global distribution and consumption of immaterial Portland feed back into the production of material Portland? To answer these questions we look to the realm of social media, specifically the popular image-based service Instagram. For the uninitiated, Instagram is a web-based social media service that allows pictures to be shared and seen by anyone that follows a person or business’ Instagram account. Actions include posting original photos (often taken and posted with a cell phone), ‘liking’ pictures, and ‘hash-tagging’ posts with trending terms that increase visibility. Instagram presents us with a complex view of place as both material and virtual, sometimes reifying and sometimes abstracting often-contradictory understandings of place specificity. Many makers use Instagram to promote their products to a broad audience and, in doing so, makers participate in the construction of Portland’s mythology. In this paper, we use empirical insights to theorise makers’ role in shaping and cultivating the virtual and material aspects of place. Additionally, we discuss how makers navigate the complex relationships tied to the importance of place in their specific cultural productions. In the first section, we develop the notion of a curated maker subjectivity. In the second section, we consider the relationship between subjectivity and place. Both sections emphasize how Instagram mediates the relationship between place and subjectivity. Through spotlighting particular literatures in each section, we attempt to fill a gap in the literature that addresses the relationship between subjectivity, place, and social media. Through this line of analysis, we attempt to better understand how and where Portland is made, along with the implications for Portland’s makers. Title: Where Is Portland Made? The Complex Relationship between Social Media and Place in the Artisan Economy of Portland, Oregon (USA) Author: Marotta, Stephen, Cummings, Austin, Heying, Charles H. Year: 2016 Portland, Oregon (USA) has become known for an artisanal or ‘maker’ economy that relies on a resurgence of place specificity (Heying), primarily expressed and exported to a global audience in the notion of ‘Portland Made’ (Roy). Portland Made reveals a tension immanent in the notion of ‘place’: place is both here and not here, both real and imaginary. What emerges is a complicated picture of how place conceptually captures various intersections of materiality and mythology, aesthetics and economics. On the one hand, Portland Made represents the collective brand-identity used by Portland’s makers to signify a products’ material existence as handcrafted, place-embedded, and authentic. These characteristics lead to certain assumptions about the concept of ‘local’ (Marotta and Heying): what meaning does Portland Made convey, and how is such meaning distributed? On the other hand, the seemingly intentional embedding of place-specificity in objects meant for distribution far outside of Portland begs another type of question: how does Portland come to be discursively representative of these characteristics, and how are such representations distributed to global audiences? How does this global distribution and consumption of immaterial Portland feed back into the production of material Portland? To answer these questions we look to the realm of social media, specifically the popular image-based service Instagram. For the uninitiated, Instagram is a web-based social media service that allows pictures to be shared and seen by anyone that follows a person or business’ Instagram account. Actions include posting original photos (often taken and posted with a cell phone), ‘liking’ pictures, and ‘hash-tagging’ posts with trending terms that increase visibility. Instagram presents us with a complex view of place as both material and virtual, sometimes reifying and sometimes abstracting often-contradictory understandings of place specificity. Many makers use Instagram to promote their products to a broad audience and, in doing so, makers participate in the construction of Portland’s mythology. In this paper, we use empirical insights to theorise makers’ role in shaping and cultivating the virtual and material aspects of place. Additionally, we discuss how makers navigate the complex relationships tied to the importance of place in their specific cultural productions. In the first section, we develop the notion of a curated maker subjectivity. In the second section, we consider the relationship between subjectivity and place. Both sections emphasize how Instagram mediates the relationship between place and subjectivity. Through spotlighting particular literatures in each section, we attempt to fill a gap in the literature that addresses the relationship between subjectivity, place, and social media. Through this line of analysis, we attempt to better understand how and where Portland is made, along with the implications for Portland’s makers. Close

• 28740. [Article] Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence

  While silicon has long been utilized for its electronic properties, its use as an optical material has largely been limited due to the poor efficiency of interband transitions. However, discovery of visible ...

  Citation × Citation Citation Abstract Copy Title: Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence Author: Radlinger, Christine Marie Year: 2017 While silicon has long been utilized for its electronic properties, its use as an optical material has largely been limited due to the poor efficiency of interband transitions. However, discovery of visible photoluminescence (PL) from nanocrystalline silicon in 1990 triggered many ensuing research efforts to optimize PL from nanocrystalline silicon for optical applications. Currently, use of photoluminescent silicon nanoparticles (Si NPs) is commercially limited by: 1) the instability of the energy and intensity of the PL, and 2) the low quantum yield of interband PL from Si NPs. Herein, red-emitting, hydrogen-passivated silicon nanoparticles (H-Si NPs) were synthesized by thermally-induced disproportionation of a HSiCl3-derived (HSiO1.5)n polymer. The H-Si NPs produced by this method were then subjected to various chemical and physical environments to assess the long-term stability of the optical properties as a function of changing surface composition. This dissertation is intended to elucidate correlations between the reported PL instability and the observed changes in the Si NP surface chemistry over time and as a function of environment. First, the stability of the H-Si NP surface at slightly elevated temperatures towards reactivity with a simple alkane was probed. The H-Si NPs were observed by FT-IR spectroscopy to undergo partial hydrosilylation upon heating in refluxing hexane, in addition to varying degrees of surface oxidation. The unexpected reactivity of the Si surface in n-hexane supports the unstable nature of the H-Si NP surface, and furthermore implicates the presence of highly-reactive Si radicals on the surfaces of the Si NPs. We propose that reaction of alkene impurities with the Si surface radicals is largely responsible for the observed surface alkylation. However, we also present an alternate mechanism by which Si surface radicals could react with alkanes to result in alkylation of the surface. Next, the energy and intensity stability of the interband PL from H-Si NPs in the presence of a radical trap was probed. Upon addition of (2,2,6,6,-tetramethyl-piperidin-1-yl)oxyl (TEMPO), the energy and intensity of the interband transition was observed to change over time, dependent on the reaction conditions. First, when the reaction occurred at 4ºC with minimal light exposure, the interband transition exhibited a gradual hypsochromic shift to between 595 nm and 655 nm, versus the λmax of the original low energy emission peak at 700 nm, depending on the amount of TEMPO in the sample. Second, when the reaction proceeded at room temperature with frequent exposure to 360 nm irradiation, the original interband transition at 660 nm was quenched while a new peak at 575 nm developed. Based on all the data collected and analyzed, we assign the 595 -- 655 nm transition as due to interband exciton recombination from Si NPs with reduced diameters relative to the original Si NPs. We furthermore assign the 575 nm transition as due to an oxide-related defect state resulting from rapid oxidation of photo-excited Si NPs. Title: Investigation into Effects of Instability and Reactivity of Hydride-Passivated Silicon Nanoparticles on Interband Photoluminescence Author: Radlinger, Christine Marie Year: 2017 While silicon has long been utilized for its electronic properties, its use as an optical material has largely been limited due to the poor efficiency of interband transitions. However, discovery of visible photoluminescence (PL) from nanocrystalline silicon in 1990 triggered many ensuing research efforts to optimize PL from nanocrystalline silicon for optical applications. Currently, use of photoluminescent silicon nanoparticles (Si NPs) is commercially limited by: 1) the instability of the energy and intensity of the PL, and 2) the low quantum yield of interband PL from Si NPs. Herein, red-emitting, hydrogen-passivated silicon nanoparticles (H-Si NPs) were synthesized by thermally-induced disproportionation of a HSiCl3-derived (HSiO1.5)n polymer. The H-Si NPs produced by this method were then subjected to various chemical and physical environments to assess the long-term stability of the optical properties as a function of changing surface composition. This dissertation is intended to elucidate correlations between the reported PL instability and the observed changes in the Si NP surface chemistry over time and as a function of environment. First, the stability of the H-Si NP surface at slightly elevated temperatures towards reactivity with a simple alkane was probed. The H-Si NPs were observed by FT-IR spectroscopy to undergo partial hydrosilylation upon heating in refluxing hexane, in addition to varying degrees of surface oxidation. The unexpected reactivity of the Si surface in n-hexane supports the unstable nature of the H-Si NP surface, and furthermore implicates the presence of highly-reactive Si radicals on the surfaces of the Si NPs. We propose that reaction of alkene impurities with the Si surface radicals is largely responsible for the observed surface alkylation. However, we also present an alternate mechanism by which Si surface radicals could react with alkanes to result in alkylation of the surface. Next, the energy and intensity stability of the interband PL from H-Si NPs in the presence of a radical trap was probed. Upon addition of (2,2,6,6,-tetramethyl-piperidin-1-yl)oxyl (TEMPO), the energy and intensity of the interband transition was observed to change over time, dependent on the reaction conditions. First, when the reaction occurred at 4ºC with minimal light exposure, the interband transition exhibited a gradual hypsochromic shift to between 595 nm and 655 nm, versus the λmax of the original low energy emission peak at 700 nm, depending on the amount of TEMPO in the sample. Second, when the reaction proceeded at room temperature with frequent exposure to 360 nm irradiation, the original interband transition at 660 nm was quenched while a new peak at 575 nm developed. Based on all the data collected and analyzed, we assign the 595 -- 655 nm transition as due to interband exciton recombination from Si NPs with reduced diameters relative to the original Si NPs. We furthermore assign the 575 nm transition as due to an oxide-related defect state resulting from rapid oxidation of photo-excited Si NPs. Close