509 research outputs found
Unemployment with Observable Aggregate Shocks
Consider an economy subject to two kinds of shocks: (a) an observable shock to the relative demand for final goods which causes dispersion in relative prices, and (b) shocks, unobservable by workers, to the technology for transforming intermediate goods into final goods. A worker in a particular intermediate goods industry knows that the unobserved price of his output is determined by (1) the technological shock that determines which final goods industry uses his output intensively and (2) the price of the final good that uses his output intensively. When there is very little relative price dispersion among final goods, then it doesn't matter which final goods industry uses the worker's output. Thus the technological shock is of very little importance in creating uncertainty about the worker's marginal product when there is little dispersion of relative prices. Hence an increase in the dispersion of relative prices amplifies the effect of technological uncertainty on a worker's marginal value product. We consider a model of optimal labor contracts in a situation where the workers have less information than the firm about their marginal value product. A relative price shock of the type described above increases the uncertainty which workers have about their marginal value product. We show that with an optimal asymmetric information employment contract the industries which are adversely affected by the relative price shock will contract more than they would under complete information (i.e., where workers could observe their marginal value product). On the other hand the industry which is favorably affected by the relative price shock will - not expand by more than would be the case under complete information. Hence an observed relative demand shock, which would leave aggregate employment unchanged under complete information, will cause aggregate employment to fall under asymmetric information about the technological shock.
An Intertidal Sea Star Adjusts Thermal Inertia to Avoid Extreme Body Temperatures
The body temperature of ectotherms is influenced by the interaction of abiotic conditions, morphology, and behavior. Although organisms living in different thermal habitats may exhibit morphological plasticity or move from unfavorable locations, there are few examples of animals adjusting their thermal properties in response to short-term changes in local conditions. Here, we show that the intertidal sea star Pisaster ochraceus modulates its thermal inertia in response to prior thermal exposure. After exposure to high body temperature at low tide, sea stars increase the amount of colder than-air fluid in their coelomic cavity when submerged during high tide, resulting in a lower body temperature during the subsequent low tide. Moreover, this buffering capacity is more effective when seawater is cold during the previous high tide. This ability to modify the volume of coelomic fluid provides sea stars with a novel thermoregulatory backup when faced with prolonged exposure to elevated aerial temperatures
Improving subtropical grass pastures on the south coast of Western Australia
This bulletin reports on the findings of a research project funded by DPIRD and MLA that investigated methods to improve legume content and increase production of both kikuyuand panic-based pastures on the south coast of WA.https://researchlibrary.agric.wa.gov.au/bulletins/1236/thumbnail.jp
Assessment of Water Quality Benefits from Stormwater Treatment Train and Ocean Outfall for the Main Street Drainage Basin in N. Myrtle Beach
2014 S.C. Water Resources Conference - Informing Strategic Water Planning to Address Natural Resource, Community and Economic Challenge
Virtual Mentorship of Teacher Leaders: The Ripple Effect
Abstract
In this paper, the authors reflect on the first completely online mathematics specialist preparation and mentoring program. Candidates across Virginia successfully completed this program and are now serving as teacher leaders, interventionists, department leaders, instructional coaches, mentors, and program specialists. They are impacting mathematics instruction across the state at all levels. As two mathematics specialists serving as mentors and two candidates, we share our thoughts and ideas as we continue to learn from our mentorship process. The goal is to provide continuous professional development as candidates share problems, successes, research, and best practices to improve mathematics teaching and learning. In our situation, virtual mentoring is a vital support to long-term development, growth, and success of mathematics teacher leaders. Keeping in touch with fellow leaders has benefitted us personally and professionally. We will discuss the benefits and constraints of online mentoring and how it can be a model for other virtual mentorship programs
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Unemployment with Observable Aggregate Shocks
A general equilibrium model of' optimal employment contracts is developed where firms have better information about labor's marginal product than workers. It is optimal for the wage to be tied to the level of employment, to prevent the firm from falsely stating that the marginal product is low and cutting the wage. It is shown that an observed aggregate shock that leads to an interindustry shift in labor demand and that would have no effect on total employment under symmetric information leads to a reduction in employment when firms and workers have asymmetric information.Economic
Glacial Changes Between 1985-2009 and Implications for Volcanic Hazards at Mt. Rainier, Washington
Therrmal Infrared Landsat scenes (Band 6) were collected and analyzed to quantify area changes and rates of change of Mt. Rainier glaciers between 1985 and 2009. Glacier change data was compared to measurements made by the United States Geological Survey (USGS) and the Global Land Ice Measurements from Space (GLIMS) project. The modeled glacier area at Mt. Rainier for the last 10 ka was then compared to the eruptive history of Mt. Rainier and other Cascade volcanoes to examine correlations. Landsat scenes show a steady decrease in glacier area at Mt. Rainier, consistent with USGS and GLIMS measurements. The observed area of Mt. Rainier glaciers decreased from 85.590 km2 to 81.355 km2 (5.32%) from 1985-2009. If glacier loss continues, the risk of hazards such as debris avalanches, lahars, and jkulhlaups (glacial outburst floods) could be enhanced due to the increased amount of glacial melt. Decreases in glacier ice at Mt. Rainier could also lead to an increased risk of eruptions due to decompression of the magma chamber. A continuation of the glacier loss seen in this study could be enough to trigger decompression, especially if Mt. Rainier has a shallow magma chamber. However, it is unclear what the time lag would be between glacier loss and an eruption as well as the amount and rate of glacier loss that would be needed. Previous studies indicate that there was an increase in eruptions ~7.4-5 ka, which is ~3.6-6 ka following the last glacial maximum. During the last ~2.3 ka, eruption rates of Cascade volcanoes have increased during times when the modeled glacier area decreased. This strongly suggests a correlation between eruption rates and glacial coverage. Glaciers at Mt. Rainier should therefore continue to be closely monitored in the future because of a possible increased risk of debris avalanches, lahars, jkulhlaups, and eruptions. Satellite-based remote sensing such as the Landsat scenes used in this study can be a valuable tool for monitoring Mt. Rainier glaciers. Future monitoring through remote sensing would allow glacier areas to be consistently tracked and provide data needed to assess hazard risks.Boone Pickens School of Geolog
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Oceanographic influences on rocky intertidal communities : coastal upwelling, invertebrate growth rates, and keystone predation
The influence of large-scale processes on natural communities has become one of the central issues of modern ecology. I combined field and laboratory studies to investigate the effects of variation in coastal upwelling on rocky intertidal communities along the central Oregon coast. I examined whether the growth of intertidal barnacles (Balanus glandula and Chthamalus dalli) at two sites was linked to nearshore phytoplankton abundance. Short-term growth rates were low during a persistent upwelling event and increased two to three-fold during the subsequent relaxation of upwelling. Although this increase coincided with a large phytoplankton bloom at one site, parallel increases in growth occurred at a second site where no bloom was recorded. Published analyses of barnacle stomach contents suggest that zooplankton may be an important component of barnacle diets. Barnacle growth may thus be enhanced during upwelling relaxations through the combined benefits of more phytoplankton, more zooplankton, and warmer water temperatures. In laboratory studies, I tested the hypothesis that upwelling-related variation in water temperature regulates the feeding, growth, and energetics of two intertidal predators, the sea star Pisaster ochraceus and whelk Nucella canaliculata. Sea stars and whelks maintained at 9°C generally consumed 30% fewer mussels than those at 12°C. Animals that were exposed to cyclic temperatures (alternating between 12°C and 9°C every two weeks) tended to grow faster than those held at constant temperatures. Consumers in upwelling systems may thus feed intensely during periods of warmer water while benefiting from reduced metabolic costs during cold-water intrusions. I conducted field experiments to quantify the effect of small changes in water temperature on the interaction between a keystone predator, Pisaster ochraceus, and the intertidal mussel Mytilus californianus. Per capita and per population effects of sea stars on transplanted mussels were sharply reduced during a persistent cold-water upwelling
event. Interannual variation in the frequency and intensity of upwelling may thus alter
community dynamics through effects on this keystone interaction. Taken together, these studies suggest that upwelling-related variation in nearshore conditions can profoundly influence intertidal systems at the organismal, population, and community level
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