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• 351. [Article] A Phenomenological Study of the Lived Experiences of Parents of Young Children with Autism Receiving Special Education Services

  Over the past two decades reported rates of autism have steadily risen. The current incidence is 1 in 68 children. While autism can be reliably diagnosed at 18 months in most children with the condition, ...

  Citation × Citation Citation Abstract Copy Title: A Phenomenological Study of the Lived Experiences of Parents of Young Children with Autism Receiving Special Education Services Author: Barrow, Donna Marie Year: 2017 Over the past two decades reported rates of autism have steadily risen. The current incidence is 1 in 68 children. While autism can be reliably diagnosed at 18 months in most children with the condition, specialized autism treatment rarely begins before a child's third or fourth birthday. As screening and diagnosis procedures improve so does the need for effective early interventions for autism. Researchers and professionals have expressed a growing concern over the need for effective early interventions for infants and toddlers with autism. At the same time, there is a dearth of qualitative research exploring the needs and experiences of parents with a very young child with autism. Employing a phenomenological framework, the purpose of this study was to investigate the lived experiences of parents of a young child with autism receiving early special education services. Unstructured interviews and photo elicitation were used to generate rich, detailed descriptions of the phenomenon. Data analysis from photographic images and narrative dialogues illuminated six essential themes across participants: (a) parents as pioneers: forging the way for future families; (b) making the journey as a family; (c) navigating uncharted service systems; (d) overcoming challenges and obstacles; (e) resilience, ingenuity and hope; and (f) reflecting on the first three years and looking forward. Participants expressed that they felt this study gave them a "voice" in the research literature. This study is one of the first to investigate the lived experiences of parents as they seek and secure autism services for their child under five with autism. Title: A Phenomenological Study of the Lived Experiences of Parents of Young Children with Autism Receiving Special Education Services Author: Barrow, Donna Marie Year: 2017 Over the past two decades reported rates of autism have steadily risen. The current incidence is 1 in 68 children. While autism can be reliably diagnosed at 18 months in most children with the condition, specialized autism treatment rarely begins before a child's third or fourth birthday. As screening and diagnosis procedures improve so does the need for effective early interventions for autism. Researchers and professionals have expressed a growing concern over the need for effective early interventions for infants and toddlers with autism. At the same time, there is a dearth of qualitative research exploring the needs and experiences of parents with a very young child with autism. Employing a phenomenological framework, the purpose of this study was to investigate the lived experiences of parents of a young child with autism receiving early special education services. Unstructured interviews and photo elicitation were used to generate rich, detailed descriptions of the phenomenon. Data analysis from photographic images and narrative dialogues illuminated six essential themes across participants: (a) parents as pioneers: forging the way for future families; (b) making the journey as a family; (c) navigating uncharted service systems; (d) overcoming challenges and obstacles; (e) resilience, ingenuity and hope; and (f) reflecting on the first three years and looking forward. Participants expressed that they felt this study gave them a "voice" in the research literature. This study is one of the first to investigate the lived experiences of parents as they seek and secure autism services for their child under five with autism. Close

• 352. [Article] Returning to Learn: Research and the Prodigal Student

  Returning students - those with a significant lapse in time during their formal education - make up a large and growing percentage of the student population at Portland State University (PSU). Over 40% ...

  Citation × Citation Citation Abstract Copy Title: Returning to Learn: Research and the Prodigal Student Author: Ford, Emily, Farkas, Meredith G, Blalock-Koral, Molly Year: 2013 Returning students - those with a significant lapse in time during their formal education - make up a large and growing percentage of the student population at Portland State University (PSU). Over 40% of PSU undergraduates are over 26 years of age and 21% of graduate students over 39. Given returning students’ experiences in the work force, motivations for learning, and the lapse of time since conducting academic research, returning students may approach research differently than traditional students. Despite the size of this student population at PSU and the growth of the returning student demographic in higher education, very little research has been conducted regarding this demographic’s research habits and skills. Over the course of two academic quarters, three librarians from Portland State University conducted an ethnographic study of returning students’ research habits. Librarians collected data using direct observation, research journals, photo diaries, focus groups, surveys and semi-structured interviews. The goals of this research were to describe returning students’ research habits and to identify potential improvements to library services and instruction for returning students at PSU. Returning to Learn: Research and the Prodigal Student will present the study’s initial findings, outline recommendations resulting from the research, and identify further research opportunities regarding this unique and growing student population. These findings will allow other academic libraries to learn about returning students’ research habits, and help them to identify potential changes in or additions to library services for this student population. Title: Returning to Learn: Research and the Prodigal Student Author: Ford, Emily, Farkas, Meredith G, Blalock-Koral, Molly Year: 2013 Returning students - those with a significant lapse in time during their formal education - make up a large and growing percentage of the student population at Portland State University (PSU). Over 40% of PSU undergraduates are over 26 years of age and 21% of graduate students over 39. Given returning students’ experiences in the work force, motivations for learning, and the lapse of time since conducting academic research, returning students may approach research differently than traditional students. Despite the size of this student population at PSU and the growth of the returning student demographic in higher education, very little research has been conducted regarding this demographic’s research habits and skills. Over the course of two academic quarters, three librarians from Portland State University conducted an ethnographic study of returning students’ research habits. Librarians collected data using direct observation, research journals, photo diaries, focus groups, surveys and semi-structured interviews. The goals of this research were to describe returning students’ research habits and to identify potential improvements to library services and instruction for returning students at PSU. Returning to Learn: Research and the Prodigal Student will present the study’s initial findings, outline recommendations resulting from the research, and identify further research opportunities regarding this unique and growing student population. These findings will allow other academic libraries to learn about returning students’ research habits, and help them to identify potential changes in or additions to library services for this student population. Close

• 353. [Article] Improving Target Amino Acid Selectivity in a Permissive Aminoacyl tRNA Synthetase Through Counter-Selection

  The amino acid acridon-2-ylalanine (Acd) can be a valuable probe of protein dynamics, either alone or as part of a Förster resonance energy transfer (FRET) or photo-induced electron transfer (eT) probe ...

  Citation × Citation Citation Abstract Copy Title: Improving Target Amino Acid Selectivity in a Permissive Aminoacyl tRNA Synthetase Through Counter-Selection Author: Sungwienwong, Itthipol, Hostetler, Zachary M., Blizzard, Robert J., Porter, Joseph J., Driggers, Camden D., Mbengi, Lea Z., Villegas, José A., Speight, Lee C., Saven, Jeffery G., Perona, John J., Kohli, Rahul M., Mehl, Ryan A., Petersson, E. James Year: 2017 The amino acid acridon-2-ylalanine (Acd) can be a valuable probe of protein dynamics, either alone or as part of a Förster resonance energy transfer (FRET) or photo-induced electron transfer (eT) probe pair. We have previously reported the genetic incorporation of Acd by an aminoacyl tRNA synthetase (RS). However, this RS, developed from a library of permissive RSs, also incorporates N-phenyl-aminophenylalanine (Npf), a trace byproduct of one Acd synthetic route. We have performed negative selections in the presence of Npf and analyzed the selectivity of the resulting AcdRSs by in vivo protein expression and detailed kinetic analyses of the purified RSs. We find that selection conferred a ∼50-fold increase in selectivity for Acd over Npf, eliminating incorporation of Npf contaminants, and allowing one to use a high yielding Acd synthetic route for improved overall expression of Acd-containing proteins. More generally, our report also provides a cautionary tale on the use of permissive RSs, as well as a strategy for improving selectivity for the target amino acid. Title: Improving Target Amino Acid Selectivity in a Permissive Aminoacyl tRNA Synthetase Through Counter-Selection Author: Sungwienwong, Itthipol, Hostetler, Zachary M., Blizzard, Robert J., Porter, Joseph J., Driggers, Camden D., Mbengi, Lea Z., Villegas, José A., Speight, Lee C., Saven, Jeffery G., Perona, John J., Kohli, Rahul M., Mehl, Ryan A., Petersson, E. James Year: 2017 The amino acid acridon-2-ylalanine (Acd) can be a valuable probe of protein dynamics, either alone or as part of a Förster resonance energy transfer (FRET) or photo-induced electron transfer (eT) probe pair. We have previously reported the genetic incorporation of Acd by an aminoacyl tRNA synthetase (RS). However, this RS, developed from a library of permissive RSs, also incorporates N-phenyl-aminophenylalanine (Npf), a trace byproduct of one Acd synthetic route. We have performed negative selections in the presence of Npf and analyzed the selectivity of the resulting AcdRSs by in vivo protein expression and detailed kinetic analyses of the purified RSs. We find that selection conferred a ∼50-fold increase in selectivity for Acd over Npf, eliminating incorporation of Npf contaminants, and allowing one to use a high yielding Acd synthetic route for improved overall expression of Acd-containing proteins. More generally, our report also provides a cautionary tale on the use of permissive RSs, as well as a strategy for improving selectivity for the target amino acid. Close

• 354. [Article] Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching

  The Meers Fault (Oklahoma) is one of few seismogenic structures with Holocene surface expression in the stable continental region of North America. Only the ~37 km-long southeastern section of the ~55 ...

  Citation × Citation Citation Abstract Copy Title: Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching Author: Hornsby, Kristofer Tyler Year: 2017 The Meers Fault (Oklahoma) is one of few seismogenic structures with Holocene surface expression in the stable continental region of North America. Only the ~37 km-long southeastern section of the ~55 km long Meers Fault is interpreted to be Holocene-active. The ~17 km-long northwestern section is considered to be Quaternary-active (pre-Holocene); however, its low-relief geomorphic expression and anthropogenic alteration have presented difficulties in evaluating the fault length and style of Holocene deformation. We reevaluate surface expression and earthquake timing of the northwestern portion of the Meers Fault to improve fault characterization, earthquake rupture models, and seismic hazard evaluations based on fault length. We use a combination of airborne lidar (0.5--2 m-resolution), historical aerial photos, and new balloon-based photogrammetric (Structure from Motion) topography (0.25--0.5 m-resolution) collected in this study to analyze and characterize the fault scarp and local fault zone geomorphology. In the northwest, complex surface deformation includes fault splays, a left step, subtle monoclinal warping, and a minor change in fault strike The fault is evident in the landscape as linear escarpments, incised channels on the up-thrown side of the scarp, and closed depressions on the downthrown side. I use topographic profiles, measured perpendicular to the fault scarp to show that the northwest scarp is characterized by decimeter surface offsets. Where the fault traverses the Post Oak Conglomerate the fault zone width rarely exceeds 25 m, in the Hennessey Shale I document an increase in fault zone width with deformation occurring over 20 m to 115 m. I further examined the northwest section of the fault in a paleoseismic excavation where weathered Permian Hennessey Shale and a ~1--2 m-thick veneer of Holocene alluvial deposits have been folded and warped during three surface-folding earthquakes. In an adjacent stream exposure these units are also faulted near the ground surface. Paleoearthquake age modeling (Oxcal) constrained by accelerated mass spectrometry (AMS) dating of detrital charcoal and optically stimulated luminescence (OSL) dating of sandy alluvial beds indicates two earthquakes occurred since ~6152-5550 cal. years BP and one possibly older event along the erosional unconformity along the Hennessey Shale bedrock. This analysis lengthens the Holocene extent of the Meers Fault by ~6 km, to ~43 km, and extends the paleoseismic record of the Meers Fault to ~9598 cal. years BP. These data will improve fault-rupture and earthquake recurrence models used for seismic hazard analysis of the Meers Fault. Title: Constraining the Holocene Extent of the Northwest Meers Fault, Oklahoma Using High-Resolution Topography and Paleoseismic Trenching Author: Hornsby, Kristofer Tyler Year: 2017 The Meers Fault (Oklahoma) is one of few seismogenic structures with Holocene surface expression in the stable continental region of North America. Only the ~37 km-long southeastern section of the ~55 km long Meers Fault is interpreted to be Holocene-active. The ~17 km-long northwestern section is considered to be Quaternary-active (pre-Holocene); however, its low-relief geomorphic expression and anthropogenic alteration have presented difficulties in evaluating the fault length and style of Holocene deformation. We reevaluate surface expression and earthquake timing of the northwestern portion of the Meers Fault to improve fault characterization, earthquake rupture models, and seismic hazard evaluations based on fault length. We use a combination of airborne lidar (0.5--2 m-resolution), historical aerial photos, and new balloon-based photogrammetric (Structure from Motion) topography (0.25--0.5 m-resolution) collected in this study to analyze and characterize the fault scarp and local fault zone geomorphology. In the northwest, complex surface deformation includes fault splays, a left step, subtle monoclinal warping, and a minor change in fault strike The fault is evident in the landscape as linear escarpments, incised channels on the up-thrown side of the scarp, and closed depressions on the downthrown side. I use topographic profiles, measured perpendicular to the fault scarp to show that the northwest scarp is characterized by decimeter surface offsets. Where the fault traverses the Post Oak Conglomerate the fault zone width rarely exceeds 25 m, in the Hennessey Shale I document an increase in fault zone width with deformation occurring over 20 m to 115 m. I further examined the northwest section of the fault in a paleoseismic excavation where weathered Permian Hennessey Shale and a ~1--2 m-thick veneer of Holocene alluvial deposits have been folded and warped during three surface-folding earthquakes. In an adjacent stream exposure these units are also faulted near the ground surface. Paleoearthquake age modeling (Oxcal) constrained by accelerated mass spectrometry (AMS) dating of detrital charcoal and optically stimulated luminescence (OSL) dating of sandy alluvial beds indicates two earthquakes occurred since ~6152-5550 cal. years BP and one possibly older event along the erosional unconformity along the Hennessey Shale bedrock. This analysis lengthens the Holocene extent of the Meers Fault by ~6 km, to ~43 km, and extends the paleoseismic record of the Meers Fault to ~9598 cal. years BP. These data will improve fault-rupture and earthquake recurrence models used for seismic hazard analysis of the Meers Fault. Close

• 355. [Article] Analyzing Experimental Data and Model Parameters: Implications for Predictions of SOA Using Chemical Transport Models

  Despite critical importance for air quality and climate predictions, accurate representation of secondary organic aerosol (SOA) formation remains elusive. An essential addition to the ongoing discussion ...

  Citation × Citation Citation Abstract Copy Title: Analyzing Experimental Data and Model Parameters: Implications for Predictions of SOA Using Chemical Transport Models Author: Barsanti, Kelley, Carlton, Annmarie G., Chung, Serena H. Year: 2013 Despite critical importance for air quality and climate predictions, accurate representation of secondary organic aerosol (SOA) formation remains elusive. An essential addition to the ongoing discussion of improving model predictions is an acknowledgement of the linkages between experimental conditions, parameter optimization and model output, as well as the linkage between empirically-derived partitioning parameters and the physicochemical properties of SOA they represent in models. In this work, a "best available" set of SOA modeling parameters is selected by comparing predicted SOA yields and mass concentrations with observed yields and mass concentrations from a comprehensive list of published smog chamber studies. Evaluated SOA model parameters include existing parameters for two product (2p) and volatility basis set (VBS) modeling frameworks, and new 2p-VBS parameters; 2p-VBS parameters are developed to exploit advantages of the VBS approach within the computationally-economical and widely-used 2p framework. Fine particulate matter (PM2.5) and SOA mass concentrations are simulated for the continental United States using CMAQv.4.7.1; results are compared for a base case (with default CMAQ parameters) and two best available parameter cases to illustrate the high- and low-NOx limits of biogenic SOA formation from monoterpenes. Results are discussed in terms of implications for current chemical transport model simulations and recommendations are provided for future modeling and measurement efforts. The comparisons of SOA yield predictions with data from 22 published chamber studies illustrate that: (1) SOA yields for naphthalene, and cyclic and > C5 straight-chain/branched alkanes are not well represented using either the newly developed or existing parameters for low-yield aromatics and lumped alkanes, respectively; and (2) for four of seven volatile organic compound+oxidant systems, the 2p-VBS parameters better represent chamber data than do the default CMAQ v.4.7.1 parameters. Using the "best available" parameters (combination of published 2p and newly derived 2p-VBS), predicted SOA mass and PM2.5 concentrations increase by up to 15% and 7%, respectively, for the high-NOxcase and up to 215% (~3 μg m−3) and 55%, respectively, for the low-NOx case. Percent bias between model-based and observationally-based secondary organic carbon (SOC) improved from −63% for the base case to −15% for the low-NOx case. The ability to robustly assign "best available" parameters in all volatile organic compound+oxidant systems, however, is critically limited due to insufficient data; particularly for photo-oxidation of diverse monoterpenes, sesquiterpenes, and alkanes under a range of atmospherically relevant conditions. Title: Analyzing Experimental Data and Model Parameters: Implications for Predictions of SOA Using Chemical Transport Models Author: Barsanti, Kelley, Carlton, Annmarie G., Chung, Serena H. Year: 2013 Despite critical importance for air quality and climate predictions, accurate representation of secondary organic aerosol (SOA) formation remains elusive. An essential addition to the ongoing discussion of improving model predictions is an acknowledgement of the linkages between experimental conditions, parameter optimization and model output, as well as the linkage between empirically-derived partitioning parameters and the physicochemical properties of SOA they represent in models. In this work, a "best available" set of SOA modeling parameters is selected by comparing predicted SOA yields and mass concentrations with observed yields and mass concentrations from a comprehensive list of published smog chamber studies. Evaluated SOA model parameters include existing parameters for two product (2p) and volatility basis set (VBS) modeling frameworks, and new 2p-VBS parameters; 2p-VBS parameters are developed to exploit advantages of the VBS approach within the computationally-economical and widely-used 2p framework. Fine particulate matter (PM2.5) and SOA mass concentrations are simulated for the continental United States using CMAQv.4.7.1; results are compared for a base case (with default CMAQ parameters) and two best available parameter cases to illustrate the high- and low-NOx limits of biogenic SOA formation from monoterpenes. Results are discussed in terms of implications for current chemical transport model simulations and recommendations are provided for future modeling and measurement efforts. The comparisons of SOA yield predictions with data from 22 published chamber studies illustrate that: (1) SOA yields for naphthalene, and cyclic and > C5 straight-chain/branched alkanes are not well represented using either the newly developed or existing parameters for low-yield aromatics and lumped alkanes, respectively; and (2) for four of seven volatile organic compound+oxidant systems, the 2p-VBS parameters better represent chamber data than do the default CMAQ v.4.7.1 parameters. Using the "best available" parameters (combination of published 2p and newly derived 2p-VBS), predicted SOA mass and PM2.5 concentrations increase by up to 15% and 7%, respectively, for the high-NOxcase and up to 215% (~3 μg m−3) and 55%, respectively, for the low-NOx case. Percent bias between model-based and observationally-based secondary organic carbon (SOC) improved from −63% for the base case to −15% for the low-NOx case. The ability to robustly assign "best available" parameters in all volatile organic compound+oxidant systems, however, is critically limited due to insufficient data; particularly for photo-oxidation of diverse monoterpenes, sesquiterpenes, and alkanes under a range of atmospherically relevant conditions. Close

• 356. [Article] Netarts Bay, Oregon: an assessment of human impact on an estuarine system

  Problems associated with planning the future use of estuarine areas stem from: A lack of knowledge on the critical aspects of the system. Inability to predict the future changes which will occur within ...

  Citation × Citation Citation Abstract Copy Title: Netarts Bay, Oregon: an assessment of human impact on an estuarine system Author: McCallum, Larry D. Year: 1977 Problems associated with planning the future use of estuarine areas stem from: A lack of knowledge on the critical aspects of the system. Inability to predict the future changes which will occur within the system in order to effectively manage the resource base. These difficulties lie in the fact that changes within the system occur because of both "natural" and "cultural" conditions. The thesis hypothesis and subsequent research is to describe the physical changes that have occurred within the Netarts system, primarily due to man's impact. Types of data gathered for the analysis includes that on historical and current land use activities, current research findings on system characteristics, and independent research on shoreline changes and vegetation composition. Much of the historical data were taken from early manuscripts and publications. Current research data were obtained from several engineering studies of the bay, as well as a baseline study of Netarts funded by a grant from the National Science Foundation and Oregon State University. This study included an inventory of man's utilization of the resource base. Methods utilized in data analysis included aerial photo-interpretation, planimetric measurement of shoreline and vegetative alterations, and on-site inventory of current shoreline and vegetation changes. Results of the research have shown that it is possible to measure and describe changes within the Netarts Bay system. Specific findings include: A decrease in sandspit volume of nine percent between 1942 and 1974 due to construction of a boat basin and fill. Occurrence of marsh progradation in all marsh areas with sedge and low sand type showing the greatest increases between 1939-1962. A decrease in rate of marsh progradation from 1962-1974. A total decrease in tidal prism of the bay between 1957-1969 as measured by cross sectional areas. The rate of decrease is occurring at a faster rate south of the mouth of Whiskey Creek. Destruction of Chum salmon fisheries and native oyster populations due to over-harvesting and siltation. Destruction of Gaper clam beds along the eastern shore of the bay and increased erosion of the shore, due to road fill and road construction. The results of the research and subsequent findings show that it is possible to describe an estuary as a "system" that has applicability for future development of a land and water use model for an estuary. Title: Netarts Bay, Oregon: an assessment of human impact on an estuarine system Author: McCallum, Larry D. Year: 1977 Problems associated with planning the future use of estuarine areas stem from: A lack of knowledge on the critical aspects of the system. Inability to predict the future changes which will occur within the system in order to effectively manage the resource base. These difficulties lie in the fact that changes within the system occur because of both "natural" and "cultural" conditions. The thesis hypothesis and subsequent research is to describe the physical changes that have occurred within the Netarts system, primarily due to man's impact. Types of data gathered for the analysis includes that on historical and current land use activities, current research findings on system characteristics, and independent research on shoreline changes and vegetation composition. Much of the historical data were taken from early manuscripts and publications. Current research data were obtained from several engineering studies of the bay, as well as a baseline study of Netarts funded by a grant from the National Science Foundation and Oregon State University. This study included an inventory of man's utilization of the resource base. Methods utilized in data analysis included aerial photo-interpretation, planimetric measurement of shoreline and vegetative alterations, and on-site inventory of current shoreline and vegetation changes. Results of the research have shown that it is possible to measure and describe changes within the Netarts Bay system. Specific findings include: A decrease in sandspit volume of nine percent between 1942 and 1974 due to construction of a boat basin and fill. Occurrence of marsh progradation in all marsh areas with sedge and low sand type showing the greatest increases between 1939-1962. A decrease in rate of marsh progradation from 1962-1974. A total decrease in tidal prism of the bay between 1957-1969 as measured by cross sectional areas. The rate of decrease is occurring at a faster rate south of the mouth of Whiskey Creek. Destruction of Chum salmon fisheries and native oyster populations due to over-harvesting and siltation. Destruction of Gaper clam beds along the eastern shore of the bay and increased erosion of the shore, due to road fill and road construction. The results of the research and subsequent findings show that it is possible to describe an estuary as a "system" that has applicability for future development of a land and water use model for an estuary. Close

• 357. [Article] Development of a Direct, Low Pressure, Laser-Induced Fluorescence Measurement Technique for NO2., Ambient Measurements and Urban NOx Chemistry

  Nitrogen oxides control the global formation of ozone in the lower atmosphere and influence the much higher levels of ozone formed in areas subjected to photochemical air pollution. As an important member ...

  Citation × Citation Citation Abstract Copy Title: Development of a Direct, Low Pressure, Laser-Induced Fluorescence Measurement Technique for NO2., Ambient Measurements and Urban NOx Chemistry Author: George, Linda Acha Year: 1991 Nitrogen oxides control the global formation of ozone in the lower atmosphere and influence the much higher levels of ozone formed in areas subjected to photochemical air pollution. As an important member of the nitrogen oxide family, N02 plays a significant role in serving as the only known source of ozone (through photolysis) in the lower atmosphere and as sink for HO via the formation of nitric acid. Ozone can be destroyed by reaction with another member of the nitrogen oxide family, nitric oxide (NO), to reform N02. This cycle between NO, N02 and 03 is known as the NOx-03 photostationary state (PSS). Imbalances in this cycle have been used to calculate ambient levels of oxidants (such as R02 and H02) responsible for ozone production. Consequently, accurate N02 measurements are critical to making meaningful measurements of the imbalances in the NOx-03 photostationary states (PSS). A low pressure laser-excited fluorescence technique (FAGE) for the direct determination of atmospheric N02 has been developed. This technique has been explored with both a Nd-YAG laser (1.4 W, 532nm, 30Hz) and a Cu-vapor (1.2 W, 511nm, 5.6kHz) laser. The detection limits for these instruments, under laboratory conditions and a signal collection time of 20s (lOs each signal and background), have been determined to be 450 and 350pptv N02, respectively. In these systems, the background was measured by chemically reducing N02 with FeS04°7H20. Ambient measurements of the NOx-03 photostationary state (PSS) were undertaken on a rooftop monitoring site in downtown Portland, Oregon. N02 was monitored with the Cu-vapor system. Nitric oxide and ozone were monitored with standard instruments. Data for three days in 1990 are presented. Overall these data sets clearly show that despite daily changes in concentration of NO, N02 and 0 3 of factors of 4-10 each, the PSS remains relatively constant to within -50%. This is in itself strong confIrmation of the primary importance of the NOx-03 photo stationary state in controlling the concentrations of these species at these levels. In addition, these experiments also serve to demonstrate that the monitoring instruments, including FAGE-N02, are not subject to serious interferences or artifacts at these concentration levels. Title: Development of a Direct, Low Pressure, Laser-Induced Fluorescence Measurement Technique for NO2., Ambient Measurements and Urban NOx Chemistry Author: George, Linda Acha Year: 1991 Nitrogen oxides control the global formation of ozone in the lower atmosphere and influence the much higher levels of ozone formed in areas subjected to photochemical air pollution. As an important member of the nitrogen oxide family, N02 plays a significant role in serving as the only known source of ozone (through photolysis) in the lower atmosphere and as sink for HO via the formation of nitric acid. Ozone can be destroyed by reaction with another member of the nitrogen oxide family, nitric oxide (NO), to reform N02. This cycle between NO, N02 and 03 is known as the NOx-03 photostationary state (PSS). Imbalances in this cycle have been used to calculate ambient levels of oxidants (such as R02 and H02) responsible for ozone production. Consequently, accurate N02 measurements are critical to making meaningful measurements of the imbalances in the NOx-03 photostationary states (PSS). A low pressure laser-excited fluorescence technique (FAGE) for the direct determination of atmospheric N02 has been developed. This technique has been explored with both a Nd-YAG laser (1.4 W, 532nm, 30Hz) and a Cu-vapor (1.2 W, 511nm, 5.6kHz) laser. The detection limits for these instruments, under laboratory conditions and a signal collection time of 20s (lOs each signal and background), have been determined to be 450 and 350pptv N02, respectively. In these systems, the background was measured by chemically reducing N02 with FeS04°7H20. Ambient measurements of the NOx-03 photostationary state (PSS) were undertaken on a rooftop monitoring site in downtown Portland, Oregon. N02 was monitored with the Cu-vapor system. Nitric oxide and ozone were monitored with standard instruments. Data for three days in 1990 are presented. Overall these data sets clearly show that despite daily changes in concentration of NO, N02 and 0 3 of factors of 4-10 each, the PSS remains relatively constant to within -50%. This is in itself strong confIrmation of the primary importance of the NOx-03 photo stationary state in controlling the concentrations of these species at these levels. In addition, these experiments also serve to demonstrate that the monitoring instruments, including FAGE-N02, are not subject to serious interferences or artifacts at these concentration levels. Close

• 358. [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

• 359. [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

• 360. [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