13,167 research outputs found
Seroepidemiological studies of herpesvirus-associated diseases of marine turtles: Fibropapillomatosis and lung-eye-trachea disease
We have developed immunological tests that can identify marine turtles in Florida (green and loggerhead) that have been exposed
to the LETV herpesvirus. The seroepidemiological data collected provides critical evidence about the relationship between
infection with the FP-associated herpesvirus and the LETV herpesvirus. The data supports the hypothesis that LETV and FPHV
infections are independent infections of marine turtles. The data shows that wild green turtles in Florida are exposed to the
LETD-associated herpesvirus, which is the first description ofLETV infection in free-ranging marine turtles. To our knowledge,
the antigenic proteins identified in this study are not only the first proteins from a reptilian herpesvirus to be cloned and
expressed, but they represent the first reptilian herpesvirus proteins to be identified as immunogenic in their host species. (16 page document
Further strategies for evaluating the etiological role of a tumor-associated herpesvirus in marine turtle fibropapillomatosis
In 1992, an interdisciplinary research team headquartered at the University of Florida
began studies in key targeted areas of fibropapillomatosis (FP) etiology and
pathogenesis. At that time, little was known about FP outside of field studies
documenting its prevalence in different areas of the world and studies of tumor
histopathology. Our primary objective was to develop a broad-based scientific
understanding of FP by applying principles of tumor biology, immunology, pathology,
virology, molecular biology, and epidemiology to FP in the green turtle, Chelonia
mydas. Long-term goals included the development of assays for FP and study of any
role of environmental co-factors in the disease. This report is a continuation of that
effort and the results reported here bring us closer to understanding the role of a
tumor-associated herpesvirus in marine turtle fibropapillomatosis.
This research has demonstrated that marine turtle herpesviruses can persist for
extended periods of time as infectious agents in the marine environment and that wild
green turtles in Florida are exposed to the LETD-associated herpesvirus. This is the
first description of LETV infection in free-ranging. marine turtles. In addition, data is
presented that supports the hypothesis that LETV and FPHV infections are
independent. These data reveal new levels of complexity that must be addressed
before reliable serodiagnostic assays for herpesvirus infections of chelonians can be
developed for widespread application. The results reported here also raise new
concerns about the potential impact of infections by new herpesviruses on populations
of wild marine turtles, an area which has previously been unexplored by turtle
biologists. (8 page document
Measuring consumption smoothing in CEX data
This paper proposes and implements a new method of measuring the degree of consumption smoothing using data from the Consumer Expenditure Survey. The structure of this Survey is such that estimators previously used in the literature are inconsistent, simply because income is measured annually and consumption is measured quarterly. We impose an AR(1) structure on the income process to obtain a proxy for quarterly income through a projection on annual income. By construction, this proxy gives rise to a measurement error which is orthogonal to the proxy itself - as opposed to the unobserved regressor - leading to a consistent estimator. We contrast our estimates with the output of two estimators used in the literature. We show that while the first (OLS) estimator tends to overstate the degree of risk sharing, the second (IV) estimator grossly understates it <br><br> Keywords; risk sharing, consumption smoothing, income risk, projection
Satisfaction in life conditions and well-being
In this note we focus on the relations between analytical life satisfaction measures and a general well-being indicator, measured by the two general subjective well-being (SWB) questions. A global SWB factor, measured by the single happiness and by the general life satisfaction questions, is explained through regression of first order factors on the questionnaire of satisfaction in the life domains. The research is based on the 2008 wave of the European Value Study (EVS) for Luxembourg. The validity of the personal living conditions as a measure of general well-being has been assessed by a MIMIC-model. Therefore, satisfaction in personal affairs indicators can constitute an enrichment of general well-being measures.subjective well-being; Mimic-model; EVS wave 2008 Luxembourg
Should day care be subsidized?
In an economy with distortionary taxes on labor, can subsidies on day care, financed by an increase in taxes, raise welfare by encouraging women with small children to work? We show, within a heterogeneous-agent life-cycle framework, that the Ramsey optimal policy consists in equalizing consumption/leisure wedges over the life cycle and across agents. A simple way to implement this is to make day care expenses tax deductible. Calibrating our model to Germany, we find that tax deductibility for day care expenses leads to an approximate doubling of labor supply for both married and single mothers with small children. The overall welfare gain from optimal reform corresponds to a 1.0 percent increase in consumption.Female labor force participation; Germany; day care subsidies
The Supply of Catastrophe Insurance Under Regulatory Constraints
Klein and Kleindorfer provide a brief overview of the current extent of their research on this topic. The intent of this research is to empirically address interactions across the multiple stakeholders in the Catastrophe Insurance Business, i.e. homeowners, businesses, insurers, reinsurers, the construction and real estate sector, and regulatory institutions. Their analysis is aimed at addressing three questions: What is the structure and performance of the catastrophe insurance market? How do factors such as, interdependencies, profits, risk exposures, and distribution impact the performance of the market? What is the impact of regulation of this market on pricing adequacy, pricing precision, and financial risk? What is the current state of the market, and what future sustainable states of the market are possible? This paper is primarily devoted to describing what authors consider to be the structural drivers of supply and demand and the impact of regulatory controls. These drivers are: "Demand structure" (i.e. why consumers buy what they do) obviously contains several components. Items such as location, demography, price, policy features such as the presence of absence of bundling, "quality" effects such as perceived solvency and claims processes, and finally, how products are distributed, all impact consumer choice. In addition, consumers have other risk management options open to them, the most obvious being where to live, what type of construction to choose and what type of "mitigation", if any to employ. "Supply Structure" describes how the consumer business of insurance is conducted. Salient features would be the degree of competition, geography, profitability, solvency, exposure, loss costs, marketing costs, organizational form, financial structure, and regulatory/solvency constraints. Obviously, insurance companies attempt to maximize profits in the face of these variables "Regulatory Impact" on such things as pricing adequacy, pricing precision, and financial risk has important effects on all parties. In particular the freedom to manage ones risk exposure is critical to everyone from the individual consumer to the largest company, and regulation may produce. In an analysis to come later, the researchers will utilize detailed premium record data obtained from ISO on insurance transactions, supplemented by information on expected costs for different policies and risk characteristics. The data will, for the first time, provide and empirically grounded understanding of the supply and demand for CAT-related coverage provided in residential insurance policies. The study will seek to identify the factors that most affect supply and demand and the magnitudes of their relative effects, including the pricing of CAT coverage and alternative policy provisions.
Efficacy of the DFT+U formalism for modeling hole polarons in perovskite oxides
We investigate the formation of self-trapped holes (STH) in three
prototypical perovskites (SrTiO3, BaTiO3, PbTiO3) using a combination of
density functional theory (DFT) calculations with local potentials and hybrid
functionals. First we construct a local correction potential for polaronic
configurations in SrTiO3 that is applied via the DFT+U method and matches the
forces from hybrid calculations. We then use the DFT+U potential to search the
configuration space and locate the lowest energy STH configuration. It is
demonstrated that both the DFT+U potential and the hybrid functional yield a
piece-wise linear dependence of the total energy on the occupation of the STH
level suggesting that self-interaction effects have been properly removed. The
DFT+U model is found to be transferable to BaTiO3 and PbTiO3, and formation
energies from DFT+U and hybrid calculations are in close agreement for all
three materials. STH formation is found to be energetically favorable in SrTiO3
and BaTiO3 but not in PbTiO3, which can be rationalized by considering the
alignment of the valence band edges on an absolute energy scale. In the case of
PbTiO3 the strong coupling between Pb 6s and O 2p states lifts the valence band
minimum (VBM) compared to SrTiO3 and BaTiO3. This reduces the separation
between VBM and STH level and renders the STH configuration metastable with
respect to delocalization (band hole state). We expect that the present
approach can be adapted to study STH formation also oxides with different
crystal structures and chemical composition.Comment: 7 pages, 6 figure
The demand for homeowners insurance with bundled catastrophe coverages : Wharton project on managing catastrophic risks
In this paper, we estimate the demand for homeowner insurance in Florida. Since we are interested in a number of factors influencing demand, we approach the problem from two directions. We first estimate two hedonic equations representing the premium per contract and the price mark-up. We analyze how the contracts are bundled and how contract provisions, insurer characteristics and insured risk characteristics and demographics influence the premium per contract and the price mark-up. Second, we estimate the demand for homeowners insurance using two-stage least squares regression. We employ ISO's indicated loss costs as our proxy for real insurance services demanded. We assume that the demand for coverage is essentially a joint demand and thus we can estimate the demand for catastrophe coverage separately from the demand for noncatastrophe coverage. We determine that price elasticities are less elastic for catastrophic coverage than for non-catastrophic coverage. Further estimated income elasticities suggest that homeowners insurance is an inferior good. Finally, we conclude based on the results of a selection model that our sample of ISO reporting companies well represents the demand for insurance in the Florida market as a whole
Covid: how corporations can improve their impact on society
As the COVID-19 crisis began to impact the work of changemakers around the world, I felt it was important to create a community where people responsible for social change could get ideas and inspiration in the face of an unprecedented level of uncertainty about the future
Predictive relationships of teacher efficacy, geometry knowledge for teaching, and the cognitive levels of teacher practice on student achievement.
This study explored the predictive relationships of teacher efficacy, teacher knowledge, and teacher practices with student achievement. More specifically, secondary mathematics teachers\u27 efficacy beliefs, geometry knowledge for teaching, and the cognitive complexity of the teachers\u27 classroom practices were examined for 72 teachers in both urban and rural districts across Kentucky, along with the student achievement data of their students. Teacher and student data were obtained from the NSF-funded Geometry Assessment for Secondary Teachers (GAST) project, which administered geometry teacher knowledge assessments at the beginning and end of the school year, and collected cognitive complexity data from lessons through three classroom observations. Student achievement was measured using a modified geometry end-of-course assessment with a geometry readiness test as a covariate. Teacher efficacy data was obtained from the same teachers through an online survey at the end of the GAST project. Correlation, multiple regression, and hierarchical linear modeling techniques were used to analyze the data. Results revealed that the cognitive level of teacher practices significantly predicted student achievement. This finding provides support for increasing teacher awareness of the importance of high cognitive instruction by helping them recognize the essential features of classroom activities that provide this instruction and assisting them to plan and implement high cognitive tasks in their classrooms
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