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Portland State University

2010

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Articles 31 - 49 of 49

Full-Text Articles in Life Sciences

Interview With Jacquin Dole, Riverside Farms, 2010 (Audio), Jacquin Dole Feb 2010

Interview With Jacquin Dole, Riverside Farms, 2010 (Audio), Jacquin Dole

All Sustainability History Project Oral Histories

Interview of Jacquin Dole by Paul Hopper at Riverside Farm McMinnville, Oregon on February 28th, 2010.

The interview index is available for download.


Interview With Bernard Smith, Full Of Life Farms, 2010 (Audio), Bernard Smith Feb 2010

Interview With Bernard Smith, Full Of Life Farms, 2010 (Audio), Bernard Smith

All Sustainability History Project Oral Histories

Interview of Bernard Smith by Kyle Dykstra on February 28th, 2010.

The interview index is available for download.


Interview With Katy Kolker, Portland Fruit Tree Project, 2010 (Audio), Katy Kolker Feb 2010

Interview With Katy Kolker, Portland Fruit Tree Project, 2010 (Audio), Katy Kolker

All Sustainability History Project Oral Histories

Interview of Katy Kolker by Dan Stillinger in Portland, Oregon on February 27th, 2010.

The interview index is available for download.


Interview With Allejandro Tecum, Adelante Mujeres, 2010 (Audio), Allejandro Tecum Feb 2010

Interview With Allejandro Tecum, Adelante Mujeres, 2010 (Audio), Allejandro Tecum

All Sustainability History Project Oral Histories

Interview of Allejandro Tecum by Adam Villareal at Forest Grove, Oregon on February 25th, 2010.

The interview index is available for download.


Interview With David Beller, Mercy Corp Nw, 2010 (Audio), David Beller Feb 2010

Interview With David Beller, Mercy Corp Nw, 2010 (Audio), David Beller

All Sustainability History Project Oral Histories

Interview of David Beller by Kyle Koonce at Mercy Corp Portland, Oregon on February 25th, 2010.

The interview index is available for download.


Interview With Darrell Sanders, Cully Community Garden, 2010 (Audio), Darrell Sanders Feb 2010

Interview With Darrell Sanders, Cully Community Garden, 2010 (Audio), Darrell Sanders

All Sustainability History Project Oral Histories

Interview of Darrell Sanders by Jeremy Cohen in Portland, Oregon on February 20th, 2010.

The interview index is available for download.


Biogeography Of The American Pika (Ochotona Princeps) In Oregon And Southern Washington: Illuminating Genetic Relationships Among Disjunct Populations, George Washington Batten Iii Feb 2010

Biogeography Of The American Pika (Ochotona Princeps) In Oregon And Southern Washington: Illuminating Genetic Relationships Among Disjunct Populations, George Washington Batten Iii

Dissertations and Theses

The American pika (Ochotona princeps) finds moderately warm temperatures (>25°C) lethally stressful, and at the end of the last Ice Age 10,000 years ago was forced to disperse to cooler, "sky island" mountaintops where they are almost exclusively found today. Thirty six subspecies are recognized, all established using morphological characters, and it is uncertain whether these subspecies' designations are corroborated by genetic analyses. This study elucidates three hypotheses regarding populations in Oregon and southern Washington: 1) O. p. fumosa constitutes a subspecies distinct form O. p. brunnescens, 2) the Columbia River constitutes a barrier to gene …


Efficient Encoding Of Vocalizations In The Auditory Midbrain, Lars Andreas Holmstrom Feb 2010

Efficient Encoding Of Vocalizations In The Auditory Midbrain, Lars Andreas Holmstrom

Systems Science Friday Noon Seminar Series

An important question in sensory neuroscience is what coding strategies and mechanisms are used by the brain to detect and discriminate among behaviorally relevant stimuli. To address the noisy response properties of individual neurons, sensory systems often utilize broadly tuned neurons with overlapping receptive fields at the system's periphery, resulting in homogeneous responses among neighboring populations of neurons. It has been hypothesized that progressive response heterogeneity in ascending sensory pathways is evidence of an efficient encoding strategy that minimizes the redundancy of the peripheral neural code and maximizes information throughput for higher level processing. This hypothesis has been partly supported …


Selection Ratios On Community Aggregated Traits To Estimate Ecological Filters Imposed On Species By Sites, Nathanael I. Lichti, Michael T. Murphy Feb 2010

Selection Ratios On Community Aggregated Traits To Estimate Ecological Filters Imposed On Species By Sites, Nathanael I. Lichti, Michael T. Murphy

Biology Faculty Publications and Presentations

Variation in community structure is mediated by interactions between species traits and a site's environmental characteristics. Previously, data on community composition at sites has been employed to correlate trait and environmental variables (e.g., RLQ analysis) and to predict community-level expression of quantitative traits (i.e., community aggregated traits). Here, we demonstrate that the selection ratio, a method originating in animal resource selection studies, can estimate the ecological filters that site conditions impose on species traits by combining observed community aggregated traits with null models of species availability. This flexible, nonparametric approach expresses the filter at each site as a probability density …


Symmetries Of The Central Vestibular System: Forming Movements For Gravity And A Three-Dimensional World, Gin Mccollum, Douglas A. Hanes Jan 2010

Symmetries Of The Central Vestibular System: Forming Movements For Gravity And A Three-Dimensional World, Gin Mccollum, Douglas A. Hanes

Gin McCollum

Intrinsic dynamics of the central vestibular system (CVS) appear to be at least partly determined by the symmetries of its connections. The CVS contributes to whole-body functions such as upright balance and maintenance of gaze direction. These functions coordinate disparate senses (visual, inertial, somatosensory, auditory) and body movements (leg, trunk, head/neck, eye). They are also unified by geometric conditions. Symmetry groups have been found to structure experimentally-recorded pathways of the central vestibular system. When related to geometric conditions in three-dimensional physical space, these symmetry groups make sense as a logical foundation for sensorimotor coordination.


Phase-Linking And The Perceived Motion During Off-Vertical Axis Rotation, Jan E. Holly, Scott J. Wood, Gin Mccollum Jan 2010

Phase-Linking And The Perceived Motion During Off-Vertical Axis Rotation, Jan E. Holly, Scott J. Wood, Gin Mccollum

Gin McCollum

Human off-vertical axis rotation (OVAR) in the dark typically produces perceived motion about a cone, the amplitude of which changes as a function of frequency. This perception is commonly attributed to the fact that both the OVAR and the conical motion have a gravity vector that rotates about the subject. Little-known, however, is that this rotating-gravity explanation for perceived conical motion is inconsistent with basic observations about self-motion perception: (a) that the perceived vertical moves toward alignment with the gravito-inertial acceleration (GIA) and (b) that perceived translation arises from perceived linear acceleration, as derived from the portion of the GIA …


Living Soil And Composting: Life’S Lessons In The Learning Gardens, Dilafruz R. Williams, Jonathan Brown Jan 2010

Living Soil And Composting: Life’S Lessons In The Learning Gardens, Dilafruz R. Williams, Jonathan Brown

Educational Leadership and Policy Faculty Publications and Presentations

After we spread the chicken poop, we covered it with hay... the poop was the fertilizer and the hay was the stuff that kept the plants warm. After school l checked the garden. Empty. Nobody. I climbed the fence to check the radishes I had planted. I dug around the radishes. They seemed dead. I grabbed a magnifying glass and looked closely at the leaves. Aphids were chewing all the leaves, like ants or other bugs. I went home worried. Next day I went to check the garden. Something red flashed in my eye. I panicked. "Yhaaaa!" I screamed with …


The Isolation Of Viruses Infecting Archaea, Kenneth M. Stedman, Kate Porter, Mike L. Dyall-Smith Jan 2010

The Isolation Of Viruses Infecting Archaea, Kenneth M. Stedman, Kate Porter, Mike L. Dyall-Smith

Biology Faculty Publications and Presentations

A mere 50 viruses of Archaea have been reported to date; these have been investigated mostly by adapting methods used to isolate bacteriophages to the unique growth conditions of their archaeal hosts. The most numerous are viruses of thermophilic Archaea. These viruses have been discovered by screening enrichment cultures and novel isolates from environmental samples for their ability to form halos of growth inhibition, or by using electron microscopy to screen enrichment cultures for virus-like particles. Direct isolation without enrichment has not yet been successful for viruses of extreme thermophiles. On the other hand, most viruses of extreme halophiles, the …


Phase-Linking And The Perceived Motion During Off-Vertical Axis Rotation, Jan Holly, Scott Wood, Gin Mccollum Jan 2010

Phase-Linking And The Perceived Motion During Off-Vertical Axis Rotation, Jan Holly, Scott Wood, Gin Mccollum

Mathematics and Statistics Faculty Publications and Presentations

Human off-vertical axis rotation (OVAR) in the dark typically produces perceived motion about a cone, the amplitude of which changes as a function of frequency. This perception is commonly attributed to the fact that both the OVAR and the conical motion have a gravity vector that rotates about the subject. Little-known, however, is that this rotating-gravity explanation for perceived conical motion is inconsistent with basic observations about self-motion perception: (a) that the perceived vertical moves toward alignment with the gravito-inertial acceleration (GIA) and (b) that perceived translation arises from perceived linear acceleration, as derived from the portion of the GIA …


Spatial Segregation Of The Sexes In A Salt Marsh Grass Distichlis Spicata (Poaceae), Charlene Ashley Mercer Jan 2010

Spatial Segregation Of The Sexes In A Salt Marsh Grass Distichlis Spicata (Poaceae), Charlene Ashley Mercer

Dissertations and Theses

Understanding the maintenance of sexual systems is of great interest to evolutionary and ecological biologists because plant systems are extremely varied. Plant sexual systems have evolved to include not only complete plants with both male and female reproduction occurring on one plant (i.e., monoecious and hermaphroditic) but also plants with male and female function on separate plants (dioecious). The dioecious reproductive system can be used to test theories on niche differentiation given that having separate plants potentially allows for the exploitation of a broader niche. This increase in the realized niche is due to the ability for separate sexes to …


Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifish Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeffrey M. Duerr, Jason E. Podrabsky Jan 2010

Mitochondrial Physiology Of Diapausing And Developing Embryos Of The Annual Killifish Austrofundulus Limnaeus: Implications For Extreme Anoxia Tolerance, Jeffrey M. Duerr, Jason E. Podrabsky

Biology Faculty Publications and Presentations

Diapausing embryos of the annual killifish Austrofundulus limnaeus have the highest reported anoxia tolerance of any vertebrate and previous studies indicate modified mitochondrial physiology likely supports anoxic metabolism. Functional mitochondria isolated from diapausing and developing embryos of the annual killifish exhibited VO2, respiratory control ratios (RCR), and P:O ratios consistent with those obtained from other ectothermic vertebrate species. Reduced oxygen consumption associated with dormancy in whole animal respiration rates are correlated with maximal respiration rates of mitochondria isolated from diapausing versus developing embryos. P:O ratios for developing embryos were similar to those obtained from adult liver, but were diminished in …


Thermocrinis Minervae Sp. Nov., A Hydrogen And Sulfur-Oxidizing, Thermophilic Member Of The Aquificales From A Costa Rican Terrestrial Hot Spring, Sara L. Caldwell, Yitai Liu, Isabel Ferrera, Terry Beveridge, Anna-Louise Reysenbach Jan 2010

Thermocrinis Minervae Sp. Nov., A Hydrogen And Sulfur-Oxidizing, Thermophilic Member Of The Aquificales From A Costa Rican Terrestrial Hot Spring, Sara L. Caldwell, Yitai Liu, Isabel Ferrera, Terry Beveridge, Anna-Louise Reysenbach

Biology Faculty Publications and Presentations

A thermophilic bacterium, designated strain CR11T , was isolated from a filamentous sample collected from a terrestrial hot spring on the south-western foothills of the Rincón volcano in Costa Rica. The Gram-negative cells are approximately 2.4–3.9 mm long and 0.5–0.6 mm wide and are motile rods with polar flagella. Strain CR11T grows between 65 and 85 6C (optimum 75 6C, doubling time 4.5 h) and between pH 4.8 and 7.8 (optimum pH 5.9–6.5). The isolate grows chemolithotrophically with S0 , S2O2{ 3 or H2 as the electron donor and with O2 (up to 16 %, v/v) as the sole electron …


Mitochondrial Inheritance And Natural Phenotypic Variation Among Caenorhabditis Briggsae Populations, Anna Luella Coleman-Hulbert Jan 2010

Mitochondrial Inheritance And Natural Phenotypic Variation Among Caenorhabditis Briggsae Populations, Anna Luella Coleman-Hulbert

Dissertations and Theses

Mutations affecting the mitochondrial electron transport chain cause numerous neurodegenerative disorders in humans and affect longevity in other organisms. A natural model system to study the relationship between mitochondrial function and aging within an evolutionary or population genetic context has been lacking. Natural populations of Caenorhabditis briggsae nematodes were recently found to harbor mitochondrial genetic variation with likely functional consequences for aging. Specifically, C. briggsae isolates containing high frequencies of a deletion mutation affecting the mitochondrial NADH dehydrogenase 5 (ND5) gene were found to have reduced reproductive fitness and lifespan and elevated levels of mutagenic superoxide. Here, rates …


Phylogeographic Patterns And Intervarietal Relationships Within Lupinus Lepidus: Morphological Differences, Genetic Similarities, Kevin Allen Weitemier Jan 2010

Phylogeographic Patterns And Intervarietal Relationships Within Lupinus Lepidus: Morphological Differences, Genetic Similarities, Kevin Allen Weitemier

Dissertations and Theses

Lupinus lepidus (Fabaceae) contains many morphologically divergent varieties and was restricted in its range during the last period of glaciation. A combination of phylogenetic (with the trnDT and LEGCYC1A loci) and population genetics approaches (with microsatellites and LEGCYC1A are used here to characterize intervarietal relationships and examine hypotheses of recolonization of areas in the Pacific Northwest affected by glaciation. Sequenced loci are not found to form a clade exclusive to L. lepidus, nor are any of the varieties found to form clades. Population genetics analyses reveal only negligible genetic structure within L. lepidus, with the majority of variation …