343 research outputs found
Examining contributions to core consumer inflation measures
The purpose of this paper is to examine the composition of inflation over time. The authors calculate the contributions to inflation for individual series of the consumer price index (CPI) and personal consumption expenditures price index (PCEPI) and then aggregate those contributions into major consumer expenditure categories. This technique provides a wealth of information concerning aggregate inflation behavior in a concise way, enabling the authors to describe the composition of inflation at any point in time. A particularly important benefit of this method is that it allows them to distinguish broad-based changes in inflation from changes due to relative price movements of a few components. The authors examine long-term trends in contributions to PCEPI core inflation and make inferences about the direction of inflation in the near term. In addition, they examine the decline in CPI core inflation over the 2002–03 period and find that the decline was largely driven by relative price changes of two components.
Effects of riparian buffer width on stream salamander populations in the southern Appalachian Mountains
The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on September 12, 2008)Vita.Thesis (M.A.) University of Missouri-Columbia 2008.Salamanders in the Appalachian region have been extensively studied, but the majority of research assessing the impacts of logging has focused on terrestrial species that are not dependent on stream habitats for egg deposition or larval development. I have collected data on both larval and adult salamanders in headwater streams in western North Carolina to determine the impacts of even-aged timber harvest on salamander populations and to assess the efficacy of riparian buffers in ameliorating these effects. My data show that larval two-lined salamanders are negatively impacted by increased stream sedimentation following riparian logging and that increasing the riparian buffer around the stream reduces sedimentation effects; larval black-bellied salamanders were not significantly affected by riparian alteration. Adult and juvenile salamanders dependent on terrestrial habitat were also affected; seal salamander densities were significantly higher in streams with little to no riparian buffer while Ocoee salamanders were significantly less abundant. It is unlikely that salamanders will persist or thrive for more than a season or two in logged forests due to a significant deterioration in body condition of Ocoee salamanders in logged riparian areas. My results indicate that current riparian forest conservation measures are inadequate to preserve either larval or adult salamander populations.Includes bibliographical reference
Factors affecting abundance, physiology, and fine-scale genetic differentiation of the western slimy salamander (Plethodon albagula)
Inferring process from pattern can be a challenging undertaking when dealing with ecological complexity. The distribution and abundance of organisms on the landscape is often interpreted through the lens of competition, movement, or physiology, as well as interactions with the abiotic environment. Further, movement, distribution, and abundance often coincide with favorable abiotic environments such as temperature, moisture, or nutrients. At its core, landscape genetics seeks to identify the spatial processes shaping the observed patterns of genetic diversity across the landscape, but most landscape genetic studies are predominantly exploratory and lack well-established hypotheses. To increase understanding of process-driven patterns in landscape genetics, I studied the western slimy salamander (Plethodon albagula) in east-central Missouri with three specific questions: (1) Where are salamanders on the landscape, and what environmental factors influence local abundance? (2) Is there a physiological constraint underlying the observed patterns of distribution and abundance? (3) How is spatial genetic structure shaped by abundance and physiology across the landscape? I utilized a combination of abundance modeling, spatial quantification of water loss using plaster of Paris models, and landscape genetics analyses to assess the factors contributing to genetic differentiation across a 1300 ha landscape. Plethodontid salamanders are highly sensitive to water loss, in part due to their lack of lungs and cutaneous respiration. I found that abundance of salamanders was best predicted by canopy cover, topographic position (ridge, slope, ravine), and the interaction between wetness and solar exposure. The spatial relationships of these factors are such that abundance is predicted to be highest in forested ravines with lower solar exposure. Plaster models deployed across the landscape served as surrogates for live salamanders to quantify rates of water loss. I found that rates of water loss across the landscape were inverselyIncludes bibliographical references
Examining contributions to core consumer inflation measures
The purpose of this paper is to examine the composition of inflation over time. The authors calculate the contributions to inflation for individual series of the consumer price index (CPI) and personal consumption expenditures price index (PCEPI) and then aggregate those contributions into major consumer expenditure categories. This technique provides a wealth of information concerning aggregate inflation behavior in a concise way, enabling the authors to describe the composition of inflation at any point in time. A particularly important benefit of this method is that it allows them to distinguish broad-based changes in inflation from changes due to relative price movements of a few components. The authors examine long-term trends in contributions to PCEPI core inflation and make inferences about the direction of inflation in the near term. In addition, they examine the decline in CPI core inflation over the 2002–03 period and find that the decline was largely driven by relative price changes of two components
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The Federal Role in Rail Transit Safety
On June 22, 2009, two transit trains in Washington, DC, collided, resulting in nine deaths and dozens of injuries. It was the worst crash in the history of the Washington Metropolitan Area Transit Authority's rail transit system. This crash has raised questions about the safety of rail transit and the government's role in ensuring that safety. Nationwide, rail transit is considered one of the safest modes of transportation. This report discusses the State Safety Oversight Program, which went into effect in 1997 and mandates that states are responsible for the safety of the rail transit systems within their borders. This report also explores several issues that Federal Transit Administration (FTA) representatives have discussed in regards to improving the Safety Oversight Program
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Protecting biodiversity: Riparian buffers directly affect Appalachian headwater salamanders [abstract]
Abstract only availableThere is growing evidence of worldwide amphibian decline. These declines are largely due to land use such as timber harvest in riparian zones. The southern Appalachian Mountains have miles of streams and arguably the greatest diversity of salamanders in the world. Salamanders are the most abundant predator of invertebrate organisms in the southern Appalachians where their biomass often exceeds that of birds and small mammals. Because salamanders have permeable skin and eggs and are sensitive to changes in the environment, they are good indicators of environmental health. Salamanders thrive in riparian areas where they need both aquatic and terrestrial habitats for foraging and reproduction. My study specifically looks at how logging and riparian buffers affect salamanders inhabiting head water streams. The purpose of my research was to measure the density and abundance of adult salamanders in five experimental streams in North Carolina; three were logged retaining 0, 9, and 30 meter riparian buffers, while two streams were studied as controls. Salamander abundance was estimated through removal sampling at each of the streams. I collected 393 total salamanders and found that salamander densities where the highest in the 0m and 9m sites with Desmognathus monticola being the most abundant. The lowest densities were in the 30m and the two controls sites. My results have implications for the long-term persistence of salamanders in streams following logging in riparian habitats
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