Search

Search Results

• 1. [Article] Characterization of Mesoscopic Fluid-like Films with the Novel Shear-force/Acoustic Microscopy

  The shear force mechanism has been utilized as a distance regulation method in scanning probe microscopes. However, the origin of shear force is still unclear. One of the most important reasons for the ...

  Citation × Citation Citation Abstract Copy Title: Characterization of Mesoscopic Fluid-like Films with the Novel Shear-force/Acoustic Microscopy Author: Wang, Xiaohua Year: 2010 The shear force mechanism has been utilized as a distance regulation method in scanning probe microscopes. However, the origin of shear force is still unclear. One of the most important reasons for the shear-force damping is due to the presence of a water contamination layer at the sample surface in ambient conditions. Understanding the behavior of such mesoscopic fluid-like films is of significance for studies of not only scanning probe microscopy but also other complex surface phenomena, such as nanotribology, lubrication, adhesion, wetting, and the microfluidity of biological membranes. This thesis investigates, in particular, the dynamics of mesoscopic fluids confined between two sliding solid boundaries. When fluids are constrained to nanometer-sized regions, their physical properties can greatly differ from those displayed by bulk liquids. To gain an insight into the fundamental characteristics of the confined fluid films, we exploit the versatile capabilities of the novel shear-force/acoustic near-field microscope (SANM), which is able to concurrently and independently monitor the effects of the fluid-mediated interactions acting on both the microscope's probe and the sample to be analyzed. Two signals are monitored simultaneously during each experimental cycle: the tuning fork signal, which is the oscillation amplitude of the probe and gives access to the shear force; and acoustic signal, which is detected by an acoustic sensor placed under the sample. Systematic experiments are carried out to investigate the effects of probe geometry, environmental humidity, and chemical properties of probe and sample surface (water affinity: hydrophobicity or hydrophilicity) on the probe-sample interactions, expressing the influence of the fluid-like contamination films. Title: Characterization of Mesoscopic Fluid-like Films with the Novel Shear-force/Acoustic Microscopy Author: Wang, Xiaohua Year: 2010 The shear force mechanism has been utilized as a distance regulation method in scanning probe microscopes. However, the origin of shear force is still unclear. One of the most important reasons for the shear-force damping is due to the presence of a water contamination layer at the sample surface in ambient conditions. Understanding the behavior of such mesoscopic fluid-like films is of significance for studies of not only scanning probe microscopy but also other complex surface phenomena, such as nanotribology, lubrication, adhesion, wetting, and the microfluidity of biological membranes. This thesis investigates, in particular, the dynamics of mesoscopic fluids confined between two sliding solid boundaries. When fluids are constrained to nanometer-sized regions, their physical properties can greatly differ from those displayed by bulk liquids. To gain an insight into the fundamental characteristics of the confined fluid films, we exploit the versatile capabilities of the novel shear-force/acoustic near-field microscope (SANM), which is able to concurrently and independently monitor the effects of the fluid-mediated interactions acting on both the microscope's probe and the sample to be analyzed. Two signals are monitored simultaneously during each experimental cycle: the tuning fork signal, which is the oscillation amplitude of the probe and gives access to the shear force; and acoustic signal, which is detected by an acoustic sensor placed under the sample. Systematic experiments are carried out to investigate the effects of probe geometry, environmental humidity, and chemical properties of probe and sample surface (water affinity: hydrophobicity or hydrophilicity) on the probe-sample interactions, expressing the influence of the fluid-like contamination films. Close

• 2. [Article] Post-occupancy Evaluation at the Zoo: Behavioral and Hormonal Indicators of Welfare in Orangutans (Pongo pygmaeus abelii)

  An increased understanding of species-specific behavioral needs has lead zoos to focus on providing more naturalistic and stimulating environments. Scientific assessments of how changes in habitat affect ...

  Citation × Citation Citation Abstract Copy Title: Post-occupancy Evaluation at the Zoo: Behavioral and Hormonal Indicators of Welfare in Orangutans (Pongo pygmaeus abelii) Author: Tingey, Leigha Year: 2012 An increased understanding of species-specific behavioral needs has lead zoos to focus on providing more naturalistic and stimulating environments. Scientific assessments of how changes in habitat affect animal behavior are necessary in improving overall animal welfare. This study examined the move of three orangutans housed at the Oregon Zoo into a new and innovative exhibit. Post-occupancy evaluation (POE), which offers systematic information regarding the success or failure of the built environment (Maple & Finlay, 1987), was utilized to effectively evaluate the results of the move. The collection of behavioral data and adrenal activity monitoring through collection of non-invasive saliva, urine and hair provided a comprehensive methodology for comparing changes in behavior and physiological functioning. Behavioral results showed that following the move to the new enclosure animals spent less time inactive, more time at higher elevations and utilized exhibit structures at a greater frequency. Hormonal results suggest that detection of cortisol in orangutan hair could be a useful tool for monitoring chronic stress. Title: Post-occupancy Evaluation at the Zoo: Behavioral and Hormonal Indicators of Welfare in Orangutans (Pongo pygmaeus abelii) Author: Tingey, Leigha Year: 2012 An increased understanding of species-specific behavioral needs has lead zoos to focus on providing more naturalistic and stimulating environments. Scientific assessments of how changes in habitat affect animal behavior are necessary in improving overall animal welfare. This study examined the move of three orangutans housed at the Oregon Zoo into a new and innovative exhibit. Post-occupancy evaluation (POE), which offers systematic information regarding the success or failure of the built environment (Maple & Finlay, 1987), was utilized to effectively evaluate the results of the move. The collection of behavioral data and adrenal activity monitoring through collection of non-invasive saliva, urine and hair provided a comprehensive methodology for comparing changes in behavior and physiological functioning. Behavioral results showed that following the move to the new enclosure animals spent less time inactive, more time at higher elevations and utilized exhibit structures at a greater frequency. Hormonal results suggest that detection of cortisol in orangutan hair could be a useful tool for monitoring chronic stress. Close

• 3. [Article] Model-Based Information Extraction From Synthetic Aperture Radar Signals

  Synthetic aperture radar (SAR) is a remote sensing technology for imaging areas of the earth's surface. SAR has been successfully used for monitoring characteristics of the natural environment such as ...

  Citation × Citation Citation Abstract Copy Title: Model-Based Information Extraction From Synthetic Aperture Radar Signals Author: Matzner, Shari Year: 2011 Synthetic aperture radar (SAR) is a remote sensing technology for imaging areas of the earth's surface. SAR has been successfully used for monitoring characteristics of the natural environment such as land cover type and tree density. With the advent of higher resolution sensors, it is now theoretically possible to extract information about individual structures such as buildings from SAR imagery. This information could be used for disaster response and security-related intelligence. SAR has an advantage over other remote sensing technologies for these applications because SAR data can be collected during the night and in rainy or cloudy conditions. This research presents a model-based method for extracting information about a building -- its height and roof slope -- from a single SAR image. Other methods require multiple images or ancillary data from specialized sensors, making them less practical. The model-based method uses simulation to match a hypothesized building to an observed SAR image. The degree to which a simulation matches the observed data is measured by mutual information. The success of this method depends on the accuracy of the simulation and on the reliability of the mutual information similarity measure. Electromagnetic theory was applied to relate a building's physical characteristics to the features present in a SAR image. This understanding was used to quantify the precision of building information contained in SAR data, and to identify the inputs needed for accurate simulation. A new SAR simulation technique was developed to meet the accuracy and efficiency requirements of model-based information extraction. Mutual information, a concept from information theory, has become a standard for measuring the similarity between medical images. Its performance in the context of matching a simulation image to a SAR image was evaluated in this research, and it was found to perform well under certain conditions. The factors that affect its performance, and the model-based method overall, were found to include the size of the building and its orientation. Further refinements that expand the range of operational conditions for the method would lead to a practical tool for collecting information about buildings using SAR technology. This research was performed using SAR data from MIT-Lincoln Laboratory. Title: Model-Based Information Extraction From Synthetic Aperture Radar Signals Author: Matzner, Shari Year: 2011 Synthetic aperture radar (SAR) is a remote sensing technology for imaging areas of the earth's surface. SAR has been successfully used for monitoring characteristics of the natural environment such as land cover type and tree density. With the advent of higher resolution sensors, it is now theoretically possible to extract information about individual structures such as buildings from SAR imagery. This information could be used for disaster response and security-related intelligence. SAR has an advantage over other remote sensing technologies for these applications because SAR data can be collected during the night and in rainy or cloudy conditions. This research presents a model-based method for extracting information about a building -- its height and roof slope -- from a single SAR image. Other methods require multiple images or ancillary data from specialized sensors, making them less practical. The model-based method uses simulation to match a hypothesized building to an observed SAR image. The degree to which a simulation matches the observed data is measured by mutual information. The success of this method depends on the accuracy of the simulation and on the reliability of the mutual information similarity measure. Electromagnetic theory was applied to relate a building's physical characteristics to the features present in a SAR image. This understanding was used to quantify the precision of building information contained in SAR data, and to identify the inputs needed for accurate simulation. A new SAR simulation technique was developed to meet the accuracy and efficiency requirements of model-based information extraction. Mutual information, a concept from information theory, has become a standard for measuring the similarity between medical images. Its performance in the context of matching a simulation image to a SAR image was evaluated in this research, and it was found to perform well under certain conditions. The factors that affect its performance, and the model-based method overall, were found to include the size of the building and its orientation. Further refinements that expand the range of operational conditions for the method would lead to a practical tool for collecting information about buildings using SAR technology. This research was performed using SAR data from MIT-Lincoln Laboratory. Close

• 4. [Article] An Analysis of Kindergarten Children's Use of a Word Processor in Their Print Literacy Development

  Many young children appear to take delight in manipulating common elements of their environment, e.g., sticks, stones, and mud. Our ancestors also used these and other elements in order to play, explore,, ...

  Citation × Citation Citation Abstract Copy Title: An Analysis of Kindergarten Children's Use of a Word Processor in Their Print Literacy Development Author: Steger, Paul Year: 1988 Many young children appear to take delight in manipulating common elements of their environment, e.g., sticks, stones, and mud. Our ancestors also used these and other elements in order to play, explore,, and eventually create written language. In a print-laden society, young children are budding literates. Within a few years their abilities and skills evolve to the level it has taken the human species thousands of years to reach. Associated with the evolution of written language is related technology. Humans have evolved from cave art and literacy to computer art and literacy. Again, what has taken thousands of years to evolve for the species takes only a few years for today's children. Within the past ten years computers have become common literacy implements in American schools. An understanding of childrens' use of this machine is important to educators in general and educational leaders in particular. The purpose of this study was to investigate kindergarten students' use of a word processor: What developmental sequences related to print literacy reveal themselves as kindergarten children use a word processor? In what ways are these sequences the same or different than those identified by researchers studying young children's use of pencil and paper? What time commitments do children make at each stage of these developmental sequences? How do the physical attributes of the computer environment, screen color for example, influence children's behavior associated with word processing? A review of literature incorporated readings associated with research in human evolution of print literacy, literacy of technology, language and cognition plus recent research on writing and computers. A research design incorporating qualitative methods was created. Six subjects, representing a variety of backgrounds in a kindergarten class of 26 full day students, were observed for 20 weeks. For one hour each day, this kindergarten class attended a writing lab which contained eight learning centers. One of the learning centers consisted of six word processors networked to two printers. In addition to collecting student documents, both in paper and electronic form. subjects' behaviors were observed and recorded. Observational recordings were analyzed, collapsed into manageable data and re-analyzed. Subjects' evolution of writing was similar to children using pencil and paper. In addition, subject's literacy of technology evolved. Each subject displayed individual episodes of development and incorporated less mature behaviors with more mature behaviors as they evolved along their print literacy and literacy of technology continuums. It was observed that subjects intertwined print and technological behaviors and skills as they wrote with a word processor. Time relationships associated with the development of writing and environmental aspects of the word processor center did not appear important. Information Age etiquette evolved as students controlled their writing, a computer system. and worked with others. The inherent publicness of monitors contributed to meta-linguistics, sharing knowledge about technology, and problem solving among students. Young children are capable of writing with and manipulating a word processor. They are also capable of trying to solve problems of written language and computers. Educators will find that young children quickly learn Information Age tool etiquette. Title: An Analysis of Kindergarten Children's Use of a Word Processor in Their Print Literacy Development Author: Steger, Paul Year: 1988 Many young children appear to take delight in manipulating common elements of their environment, e.g., sticks, stones, and mud. Our ancestors also used these and other elements in order to play, explore,, and eventually create written language. In a print-laden society, young children are budding literates. Within a few years their abilities and skills evolve to the level it has taken the human species thousands of years to reach. Associated with the evolution of written language is related technology. Humans have evolved from cave art and literacy to computer art and literacy. Again, what has taken thousands of years to evolve for the species takes only a few years for today's children. Within the past ten years computers have become common literacy implements in American schools. An understanding of childrens' use of this machine is important to educators in general and educational leaders in particular. The purpose of this study was to investigate kindergarten students' use of a word processor: What developmental sequences related to print literacy reveal themselves as kindergarten children use a word processor? In what ways are these sequences the same or different than those identified by researchers studying young children's use of pencil and paper? What time commitments do children make at each stage of these developmental sequences? How do the physical attributes of the computer environment, screen color for example, influence children's behavior associated with word processing? A review of literature incorporated readings associated with research in human evolution of print literacy, literacy of technology, language and cognition plus recent research on writing and computers. A research design incorporating qualitative methods was created. Six subjects, representing a variety of backgrounds in a kindergarten class of 26 full day students, were observed for 20 weeks. For one hour each day, this kindergarten class attended a writing lab which contained eight learning centers. One of the learning centers consisted of six word processors networked to two printers. In addition to collecting student documents, both in paper and electronic form. subjects' behaviors were observed and recorded. Observational recordings were analyzed, collapsed into manageable data and re-analyzed. Subjects' evolution of writing was similar to children using pencil and paper. In addition, subject's literacy of technology evolved. Each subject displayed individual episodes of development and incorporated less mature behaviors with more mature behaviors as they evolved along their print literacy and literacy of technology continuums. It was observed that subjects intertwined print and technological behaviors and skills as they wrote with a word processor. Time relationships associated with the development of writing and environmental aspects of the word processor center did not appear important. Information Age etiquette evolved as students controlled their writing, a computer system. and worked with others. The inherent publicness of monitors contributed to meta-linguistics, sharing knowledge about technology, and problem solving among students. Young children are capable of writing with and manipulating a word processor. They are also capable of trying to solve problems of written language and computers. Educators will find that young children quickly learn Information Age tool etiquette. Close

• 5. [Article] Forest Resource Use, Land-Use, and Ecotourism in the Río Plátano Biosphere Reserve, Honduras

  The Río Pláttano Biosphere Reserve, a tropical rainforest reserve in the northeastern corner of Honduras, is home to several subsistence-based indigenous groups, including the Miskito, Pech and Garifuna, ...

  Citation × Citation Citation Abstract Copy Title: Forest Resource Use, Land-Use, and Ecotourism in the Río Plátano Biosphere Reserve, Honduras Author: Friedle, Christina Marie Year: 2005 The Río Pláttano Biosphere Reserve, a tropical rainforest reserve in the northeastern corner of Honduras, is home to several subsistence-based indigenous groups, including the Miskito, Pech and Garifuna, as well as the non-indigenous Ladinos. Communities within the reserve depend on forest resources, swidden agriculture, marine resources and/or small-scale ranching as the foundations for local economies. Regulations placed on these subsistence practices, after establishment of the biosphere reserve in 1980, have created unique and new pressures and resulted in a blend of traditional and innovative resource use. A notable result is the promotion of ecotourism as a solution for meeting the economic needs of local populations while conserving local resources. This thesis documents current resource use in the Miskito and Ladino communities of Banaka, Brans, and Fuente de Jacob, in the Río Pláttano Biosphere Reserve and the potential of ecotourism to maintain both local economies and consumption of tropical rainforest resources in these communities. Analysis suggests that a community-based approach to ecotourism can result in economic benefits and maintain local culture. This thesis documents current resource use (agricultural crops and trees, gathered and cultivated plants, tree-use, and hunting), resident perspectives on ecotourism development and industry, and provides the foundation for long-term monitoring and analysis on the effects of ecotomism on forest resource and land-use in the greater Banaka region. Title: Forest Resource Use, Land-Use, and Ecotourism in the Río Plátano Biosphere Reserve, Honduras Author: Friedle, Christina Marie Year: 2005 The Río Pláttano Biosphere Reserve, a tropical rainforest reserve in the northeastern corner of Honduras, is home to several subsistence-based indigenous groups, including the Miskito, Pech and Garifuna, as well as the non-indigenous Ladinos. Communities within the reserve depend on forest resources, swidden agriculture, marine resources and/or small-scale ranching as the foundations for local economies. Regulations placed on these subsistence practices, after establishment of the biosphere reserve in 1980, have created unique and new pressures and resulted in a blend of traditional and innovative resource use. A notable result is the promotion of ecotourism as a solution for meeting the economic needs of local populations while conserving local resources. This thesis documents current resource use in the Miskito and Ladino communities of Banaka, Brans, and Fuente de Jacob, in the Río Pláttano Biosphere Reserve and the potential of ecotourism to maintain both local economies and consumption of tropical rainforest resources in these communities. Analysis suggests that a community-based approach to ecotourism can result in economic benefits and maintain local culture. This thesis documents current resource use (agricultural crops and trees, gathered and cultivated plants, tree-use, and hunting), resident perspectives on ecotourism development and industry, and provides the foundation for long-term monitoring and analysis on the effects of ecotomism on forest resource and land-use in the greater Banaka region. Close

• 6. [Article] Some Relationships Between Sedimentary Trace Metal Concentrations and Freshwater Phytoplankton and Sedimentary Diatom Species Composition

  Sediments from 21 Oregon lakes were analyzed for seven metals (Fe, Mn, Zn, Cu, Co, Ni, V) in three forms (exchangeable, organic+sulfides, and oxyhydroxides+ oxides+ carbonates) using a sequential fractionation ...

  Citation × Citation Citation Abstract Copy Title: Some Relationships Between Sedimentary Trace Metal Concentrations and Freshwater Phytoplankton and Sedimentary Diatom Species Composition Author: Vogel, Allan Hayes Year: 1995 Sediments from 21 Oregon lakes were analyzed for seven metals (Fe, Mn, Zn, Cu, Co, Ni, V) in three forms (exchangeable, organic+sulfides, and oxyhydroxides+ oxides+ carbonates) using a sequential fractionation procedure. The summer epilimnetic filterable concentration of an eighth (Mo) was also determined. Sedimentary diatom remains and summer phytoplankton populations of the lakes were correlated with the 22 metal parameters and with conservative water chemistry parameters, estimators of lake productivity, and watershed geology. Both the sedimentary metals and the two populations of primary producers correlated best with the ecoregions of Omernik and Gallant (1986). A number of species possessed correlations with specific trace metal extractions or ratios of those extractions. Bloom-forming Anabaenas strongly correlated with sedimentary organic and filterable epilimnetic nickel. Possible Ni limitation of this group was observed in one Cascade lake (Lava). The ratio of organic nickel to cobalt appeared to control the abundance of several sedimentary diatoms. Organic vanadium strongly correlated with a number of diatoms, particularly in the genera, Cyclotella and Fragilaria. Possible V pollution was observed in one lake (Woahink), and frustule remains of C. stelligera significantly increased with increasing total sedimentary V concentrations there. Zinc was the trace metal most frequently found to apparently limit diatom growth. Diatoms may have developed three different responses to Zn limitation; the three groups have been labelled affinity-, velocity-, and (possibly) storage- specialists following Sommer (1985). Possible Zn pollution was observed in two lakes (Oswego and Clear). Phytoplankton and sedimentary diatoms weakly correlated with sedimentary iron by comparison to Ni, V, or Zn. Few strong relationships were observed with manganese, copper, or cobalt. No statistically significant correlations were found with molybdenum, and few correlations between a conservative chemical parameter and a species of phytoplankton were found. There was poor correlation between trace metal concentrations and lake productivity, despite frequently observed correlations between individual species and particular trace metal fractions. These findings suggest that variations in absolute trace metal concentrations, and/or ratios, may be important factors for controlling species distribution, but have relatively little influence upon lake primary productivity or standing stocks. Title: Some Relationships Between Sedimentary Trace Metal Concentrations and Freshwater Phytoplankton and Sedimentary Diatom Species Composition Author: Vogel, Allan Hayes Year: 1995 Sediments from 21 Oregon lakes were analyzed for seven metals (Fe, Mn, Zn, Cu, Co, Ni, V) in three forms (exchangeable, organic+sulfides, and oxyhydroxides+ oxides+ carbonates) using a sequential fractionation procedure. The summer epilimnetic filterable concentration of an eighth (Mo) was also determined. Sedimentary diatom remains and summer phytoplankton populations of the lakes were correlated with the 22 metal parameters and with conservative water chemistry parameters, estimators of lake productivity, and watershed geology. Both the sedimentary metals and the two populations of primary producers correlated best with the ecoregions of Omernik and Gallant (1986). A number of species possessed correlations with specific trace metal extractions or ratios of those extractions. Bloom-forming Anabaenas strongly correlated with sedimentary organic and filterable epilimnetic nickel. Possible Ni limitation of this group was observed in one Cascade lake (Lava). The ratio of organic nickel to cobalt appeared to control the abundance of several sedimentary diatoms. Organic vanadium strongly correlated with a number of diatoms, particularly in the genera, Cyclotella and Fragilaria. Possible V pollution was observed in one lake (Woahink), and frustule remains of C. stelligera significantly increased with increasing total sedimentary V concentrations there. Zinc was the trace metal most frequently found to apparently limit diatom growth. Diatoms may have developed three different responses to Zn limitation; the three groups have been labelled affinity-, velocity-, and (possibly) storage- specialists following Sommer (1985). Possible Zn pollution was observed in two lakes (Oswego and Clear). Phytoplankton and sedimentary diatoms weakly correlated with sedimentary iron by comparison to Ni, V, or Zn. Few strong relationships were observed with manganese, copper, or cobalt. No statistically significant correlations were found with molybdenum, and few correlations between a conservative chemical parameter and a species of phytoplankton were found. There was poor correlation between trace metal concentrations and lake productivity, despite frequently observed correlations between individual species and particular trace metal fractions. These findings suggest that variations in absolute trace metal concentrations, and/or ratios, may be important factors for controlling species distribution, but have relatively little influence upon lake primary productivity or standing stocks. Close

• 7. [Article] Automated Channel Assessment for Single Chip MedRadio Transceivers

  Modern implantable and body worn medical devices leverage wireless telemetry to improve patient experience and expand therapeutic options. Wireless medical devices are subject to a unique set of regulations ...

  Citation × Citation Citation Abstract Copy Title: Automated Channel Assessment for Single Chip MedRadio Transceivers Author: Hillig, Mark Alexander Year: 2013 Modern implantable and body worn medical devices leverage wireless telemetry to improve patient experience and expand therapeutic options. Wireless medical devices are subject to a unique set of regulations in which monitoring of the available frequency spectrum is a requirement. To this end, implants use software protocols to assess the in-band activity to determine which channel should be used. These software protocols take valuable processing time and possibly degrade the operational lifetime of the battery. Implantable medical devices often take advantage of a single chip transceiver as the physical layer for wireless communications. Embedding the channel assessment task in the transceiver hardware would free the limited resources of the microprocessor. This thesis proposes hardware modifications to existing transceiver architectures which would provide an automated channel assessment means for implantable medical devices. The results are applicable beyond medical device applications and could be employed to benefit any low-power, wireless, battery-operated equipment. Title: Automated Channel Assessment for Single Chip MedRadio Transceivers Author: Hillig, Mark Alexander Year: 2013 Modern implantable and body worn medical devices leverage wireless telemetry to improve patient experience and expand therapeutic options. Wireless medical devices are subject to a unique set of regulations in which monitoring of the available frequency spectrum is a requirement. To this end, implants use software protocols to assess the in-band activity to determine which channel should be used. These software protocols take valuable processing time and possibly degrade the operational lifetime of the battery. Implantable medical devices often take advantage of a single chip transceiver as the physical layer for wireless communications. Embedding the channel assessment task in the transceiver hardware would free the limited resources of the microprocessor. This thesis proposes hardware modifications to existing transceiver architectures which would provide an automated channel assessment means for implantable medical devices. The results are applicable beyond medical device applications and could be employed to benefit any low-power, wireless, battery-operated equipment. Close

• 8. [Article] Apatite Crystal Populations of the 1991 Mount Pinatubo Eruption, Philippines: Implications for the Generation of High Sulfur Apatite in Silicic Melts

  On June 15, 1991, Mount Pinatubo, Philippines, ejected 20 million tonnes of sulfur dioxide into the atmosphere, significantly impacting global climate and stratospheric ozone. Recharging basaltic magma ...

  Citation × Citation Citation Abstract Copy Title: Apatite Crystal Populations of the 1991 Mount Pinatubo Eruption, Philippines: Implications for the Generation of High Sulfur Apatite in Silicic Melts Author: Van Hoose, Ashley Elizabeth Year: 2012 On June 15, 1991, Mount Pinatubo, Philippines, ejected 20 million tonnes of sulfur dioxide into the atmosphere, significantly impacting global climate and stratospheric ozone. Recharging basaltic magma mixed into the 50 km³ dacitic magma reservoir 6 to 11 km beneath Mount Pinatubo, and triggered the 1991 eruption. The result of the magma mixing was a hybrid andesite with quenched basalt inclusions that erupted as a dome between June 7 and June 12. On June 15, approximately 5 km³ of anhydrite-bearing magma was erupted from the main phenocryst-rich, dacitic reservoir. This study will utilize this extraordinary framework of the 1991 Pinatubo eruption to investigate the systematics of sulfur uptake by apatite in order to further develop apatite as a monitor for magmatic sulfur. In the dacite and hybrid andesite, apatite occurs as individual phenocrysts (up to ~200 μm diameter) or included within anhydrite, hornblende, and plagioclase phenocrysts. In the basaltic magmatic inclusions, apatite is found as acicular microphenocrysts. Electron microprobe data collected on apatite yield low- (0.7 wt.% SO₃) apatites in all juvenile products, and show that two distinct populations of apatites exist: "silicic" apatites (hosted in dacite and andesite) and basalt apatites. Apatites crystallizing from silicic melt have predominantly low- to medium-sulfur contents, but high-sulfur apatites with as much as 1.2-1.7 wt.% SO₃ occur sporadically as inclusions in plagioclase, hornblende, Fe-Ti oxide, and anhydrite. These concentrations are much higher than what could be achieved through equilibrium crystal-melt partitioning at pre-eruption conditions (760±20°C, 220MPa, NNO+1.7, 77 ppm S in melt inclusions) and a partition coefficient of 13. Apatite in the basalt is always sulfur-rich with compositions forming a continuous array between 0.7 to 2.6 wt.% SO₃. The population of apatite that crystallized from silicic melt has elevated cerium, fluorine, and chlorine and lower magnesium concentrations (average dacite values in wt.%: 0.21 Ce₂O₃, 1.4 F, 1.1 Cl, & 0.14 MgO) relative to the population of apatite from the basalt (average basalt values in wt.%: 0.05 Ce₂O₃, 1.0 F, 0.78 Cl, & 0.22 MgO). LA-ICP-MS trace element data also show distinct apatite populations between silicic and basalt apatites. Silicic apatites have elevated REE concentrations (La avg. = 750 ppm), lower Sr (avg.= 594 ppm), and a pronounced negative Eu anomaly (avg. Eu/Eu* = 0.57) relative to basalt apatites (avg. values: 217 ppm La, 975 ppm Sr, and Eu/Eu* = 1.16). The correlation of EMP sulfur data and LA-ICP-MS trace element data show no difference between high-S and low-S silicic apatites. These compositional systematics rule out the possibility that sulfur-rich apatite from dacite are inherited from mafic magma. Sulfur element maps of apatites show no evidence of S-diffusion from anhydrite hosts. Areas of high-S concentrations show complicated patterns that suggest multiple periods of sulfur enrichment. High-S silicic apatites are likely the product of "fluid-enhanced crystallization" from early enrichment of a SO₂ rich fluid phase from the underplating basalt, which occurred prior to or at anhydrite saturation. This fluid phase is the only possible sufficient source of sulfur for generating high-S apatites in a cool, "wet", dacitic melt. The dynamics of apatite sulfur enrichment via "fluid-enhanced crystallization" is yet unclear and requires further experimental laboratory investigation. Title: Apatite Crystal Populations of the 1991 Mount Pinatubo Eruption, Philippines: Implications for the Generation of High Sulfur Apatite in Silicic Melts Author: Van Hoose, Ashley Elizabeth Year: 2012 On June 15, 1991, Mount Pinatubo, Philippines, ejected 20 million tonnes of sulfur dioxide into the atmosphere, significantly impacting global climate and stratospheric ozone. Recharging basaltic magma mixed into the 50 km³ dacitic magma reservoir 6 to 11 km beneath Mount Pinatubo, and triggered the 1991 eruption. The result of the magma mixing was a hybrid andesite with quenched basalt inclusions that erupted as a dome between June 7 and June 12. On June 15, approximately 5 km³ of anhydrite-bearing magma was erupted from the main phenocryst-rich, dacitic reservoir. This study will utilize this extraordinary framework of the 1991 Pinatubo eruption to investigate the systematics of sulfur uptake by apatite in order to further develop apatite as a monitor for magmatic sulfur. In the dacite and hybrid andesite, apatite occurs as individual phenocrysts (up to ~200 μm diameter) or included within anhydrite, hornblende, and plagioclase phenocrysts. In the basaltic magmatic inclusions, apatite is found as acicular microphenocrysts. Electron microprobe data collected on apatite yield low- (0.7 wt.% SO₃) apatites in all juvenile products, and show that two distinct populations of apatites exist: "silicic" apatites (hosted in dacite and andesite) and basalt apatites. Apatites crystallizing from silicic melt have predominantly low- to medium-sulfur contents, but high-sulfur apatites with as much as 1.2-1.7 wt.% SO₃ occur sporadically as inclusions in plagioclase, hornblende, Fe-Ti oxide, and anhydrite. These concentrations are much higher than what could be achieved through equilibrium crystal-melt partitioning at pre-eruption conditions (760±20°C, 220MPa, NNO+1.7, 77 ppm S in melt inclusions) and a partition coefficient of 13. Apatite in the basalt is always sulfur-rich with compositions forming a continuous array between 0.7 to 2.6 wt.% SO₃. The population of apatite that crystallized from silicic melt has elevated cerium, fluorine, and chlorine and lower magnesium concentrations (average dacite values in wt.%: 0.21 Ce₂O₃, 1.4 F, 1.1 Cl, & 0.14 MgO) relative to the population of apatite from the basalt (average basalt values in wt.%: 0.05 Ce₂O₃, 1.0 F, 0.78 Cl, & 0.22 MgO). LA-ICP-MS trace element data also show distinct apatite populations between silicic and basalt apatites. Silicic apatites have elevated REE concentrations (La avg. = 750 ppm), lower Sr (avg.= 594 ppm), and a pronounced negative Eu anomaly (avg. Eu/Eu* = 0.57) relative to basalt apatites (avg. values: 217 ppm La, 975 ppm Sr, and Eu/Eu* = 1.16). The correlation of EMP sulfur data and LA-ICP-MS trace element data show no difference between high-S and low-S silicic apatites. These compositional systematics rule out the possibility that sulfur-rich apatite from dacite are inherited from mafic magma. Sulfur element maps of apatites show no evidence of S-diffusion from anhydrite hosts. Areas of high-S concentrations show complicated patterns that suggest multiple periods of sulfur enrichment. High-S silicic apatites are likely the product of "fluid-enhanced crystallization" from early enrichment of a SO₂ rich fluid phase from the underplating basalt, which occurred prior to or at anhydrite saturation. This fluid phase is the only possible sufficient source of sulfur for generating high-S apatites in a cool, "wet", dacitic melt. The dynamics of apatite sulfur enrichment via "fluid-enhanced crystallization" is yet unclear and requires further experimental laboratory investigation. Close

• 9. [Article] Focus on a STEM, Based in Place, Watershed Curriculum: A confluence of stormwater, humans, knowledge, attitudes, and skills

  This case study investigated the potential of a place-based watershed curriculum, using STEM principles, to increase watershed literacy and knowledge of human impacts on stormwater in the environment. ...

  Citation × Citation Citation Abstract Copy Title: Focus on a STEM, Based in Place, Watershed Curriculum: A confluence of stormwater, humans, knowledge, attitudes, and skills Author: Schall, Lecia Molineux Year: 2015 This case study investigated the potential of a place-based watershed curriculum, using STEM principles, to increase watershed literacy and knowledge of human impacts on stormwater in the environment. A secondary goal was to examine whether the place-based connection and increased exposure to issues within their local watershed impacted the students' environmental attitudes and sense of place. Over 500 sixth graders participated in this localized curriculum, where they learned the science behind watershed issues on their own school campuses. They focused on ways humans can monitor and mitigate their impacts on stormwater, through engineering investigations. The mixed-method research study investigated the effectiveness of the OLWEDU curriculum, to address these key questions: 1) To what degree did the OLWEDU increase the students' combined watershed literacy? 2) To what extent did the OLWEDU affect their environmental attitudes? 3) How did using a STEM oriented and place-based curriculum make the learning more relevant? In order to provide a solid triangulation of data, this study used a quasi-experimental design format with multiple measures: a) A Pre-Posttest (PPT), was given to all of the students to gather quantitative changes in knowledge of watershed concepts, stormwater issues related to human impacts on the environment, and engineering techniques; b) A constructed-knowledge questionnaire (CKQ) was used with forty four of the participants, to gather additional quantitative data on the students' local watershed knowledge; c) an environmental attitudes survey (EAS) was included in this sub-sample group; d) interviews were conducted with ten of the students to examine their opinions on the STEM aspects of the curriculum in addition to the place-based connections between the unit and their community. The statistically significant results showed increases in overall watershed literacy, knowledge of human impacts on stormwater, engineering principles, and environmental attitudes. These findings will be used to improve the current curriculum, and have broader implications concerning the benefits of using a formalized middle-school 21st century standards-based curriculum to teach watershed literacy and promote pro-environmental attitudes by using a combination of Science, Technology, Engineering, and Math in a local, place-based context. Title: Focus on a STEM, Based in Place, Watershed Curriculum: A confluence of stormwater, humans, knowledge, attitudes, and skills Author: Schall, Lecia Molineux Year: 2015 This case study investigated the potential of a place-based watershed curriculum, using STEM principles, to increase watershed literacy and knowledge of human impacts on stormwater in the environment. A secondary goal was to examine whether the place-based connection and increased exposure to issues within their local watershed impacted the students' environmental attitudes and sense of place. Over 500 sixth graders participated in this localized curriculum, where they learned the science behind watershed issues on their own school campuses. They focused on ways humans can monitor and mitigate their impacts on stormwater, through engineering investigations. The mixed-method research study investigated the effectiveness of the OLWEDU curriculum, to address these key questions: 1) To what degree did the OLWEDU increase the students' combined watershed literacy? 2) To what extent did the OLWEDU affect their environmental attitudes? 3) How did using a STEM oriented and place-based curriculum make the learning more relevant? In order to provide a solid triangulation of data, this study used a quasi-experimental design format with multiple measures: a) A Pre-Posttest (PPT), was given to all of the students to gather quantitative changes in knowledge of watershed concepts, stormwater issues related to human impacts on the environment, and engineering techniques; b) A constructed-knowledge questionnaire (CKQ) was used with forty four of the participants, to gather additional quantitative data on the students' local watershed knowledge; c) an environmental attitudes survey (EAS) was included in this sub-sample group; d) interviews were conducted with ten of the students to examine their opinions on the STEM aspects of the curriculum in addition to the place-based connections between the unit and their community. The statistically significant results showed increases in overall watershed literacy, knowledge of human impacts on stormwater, engineering principles, and environmental attitudes. These findings will be used to improve the current curriculum, and have broader implications concerning the benefits of using a formalized middle-school 21st century standards-based curriculum to teach watershed literacy and promote pro-environmental attitudes by using a combination of Science, Technology, Engineering, and Math in a local, place-based context. Close

• 10. [Article] Child Welfare Workforce Turnover: Frontline Workers' Experiences with Organizational Culture and Climate, and Implications for Organizational Practice

  Public child welfare agencies experience front line worker turnover rates as high as 25% a year. Worker turnover has significant financial costs to agencies, and has been linked to negative outcomes for ...

  Citation × Citation Citation Abstract Copy Title: Child Welfare Workforce Turnover: Frontline Workers' Experiences with Organizational Culture and Climate, and Implications for Organizational Practice Author: Sage, Melanie Dawn Year: 2010 Public child welfare agencies experience front line worker turnover rates as high as 25% a year. Worker turnover has significant financial costs to agencies, and has been linked to negative outcomes for children in care. Prior research has linked organizational factors, such as organizational climate, culture, and supervisor satisfaction, to turnover intent in child welfare populations. This research uses an empowerment framework to turn to workers directly to answer the question, "What are the organizational factors that lead frontline child welfare workers to stay or leave the agency, and what, then, are the implications for agency administrators?" This study relies upon secondary data of a workforce study conducted by the Child Welfare Partnership at Portland State University's School of Social Work. The data was collected via a pilot internet survey of approximately 400 State-employed Oregon child welfare case workers across all geographic regions in the state, and focuses on workers who plan to leave for preventable reasons. This study explored links between organizational factors and turnover in a sample of Oregon public child welfare workers. This research finds that climate, culture, supervision, and knowledge of the job prior to hire are all significantly correlated with intent to leave. Climate is most significantly correlated to Intent to Leave, and explains 25% of the variance in intent to leave in a regression model. These research findings suggest that agency administrators who are interested in improving worker retention can monitor and address local culture and climate as one tool for increasing workforce stability. Retention may be improved by maintaining an organizational culture and climate that is empowering to workers and that encourages workers to be a part of the change process. Additional implications for the child welfare workforce, social work research, and social work education are discussed. Title: Child Welfare Workforce Turnover: Frontline Workers' Experiences with Organizational Culture and Climate, and Implications for Organizational Practice Author: Sage, Melanie Dawn Year: 2010 Public child welfare agencies experience front line worker turnover rates as high as 25% a year. Worker turnover has significant financial costs to agencies, and has been linked to negative outcomes for children in care. Prior research has linked organizational factors, such as organizational climate, culture, and supervisor satisfaction, to turnover intent in child welfare populations. This research uses an empowerment framework to turn to workers directly to answer the question, "What are the organizational factors that lead frontline child welfare workers to stay or leave the agency, and what, then, are the implications for agency administrators?" This study relies upon secondary data of a workforce study conducted by the Child Welfare Partnership at Portland State University's School of Social Work. The data was collected via a pilot internet survey of approximately 400 State-employed Oregon child welfare case workers across all geographic regions in the state, and focuses on workers who plan to leave for preventable reasons. This study explored links between organizational factors and turnover in a sample of Oregon public child welfare workers. This research finds that climate, culture, supervision, and knowledge of the job prior to hire are all significantly correlated with intent to leave. Climate is most significantly correlated to Intent to Leave, and explains 25% of the variance in intent to leave in a regression model. These research findings suggest that agency administrators who are interested in improving worker retention can monitor and address local culture and climate as one tool for increasing workforce stability. Retention may be improved by maintaining an organizational culture and climate that is empowering to workers and that encourages workers to be a part of the change process. Additional implications for the child welfare workforce, social work research, and social work education are discussed. Close