331 research outputs found
Developing a Comprehensive Pesticide Health Effects Tracking System for an Urban Setting: New York City’s Approach
In recent years, there have been substantial investments and improvements in federal and state surveillance systems to track the health effects from pesticide exposure. These surveillance systems help to identify risk factors for occupational exposure to pesticides, patterns in poisonings, clusters of disease, and populations at risk of exposure from pesticide use. Data from pesticide use registries and recent epidemiologic evidence pointing to health risks from urban residential pesticide use make a strong case for understanding better the sale, application, and use of pesticides in cities. In this article, we describe plans for the development of a pesticide tracking system for New York City that will help to elucidate where and why pesticides are used, potential risks to varied populations, and the health consequences of their use. The results of an inventory of data sources are presented along with a description of their relevance to pesticide tracking. We also discuss practical, logistical, and methodologic difficulties of linking multiple secondary data sources with different levels of person, place, and time descriptors
Estimating Extent of Mortality Associated with the Douglas-Fir Beetle in the Central and Northern Rockies
Data collected from Douglas-fir stands infected by the Douglas-fir beetle in Wyoming, Montana, Idaho, and Utah, were used to develop models to estimate amount of mortality in terms of basal area killed. Models were built using stepwise linear regression and regression tree approaches. Linear regression models using initial Douglas-fir basal area were built for all study sites but produce low precision estimates. Regression tree models using initial Douglas-fir basal area of stand density index or both were also build for all sites. Regression tree models provide a more realistic approach to estimate potential mortality by creating more homogenous mortality classes with reduced variance. The models developed provide land managers with a basis for determining the potential mortality should a Douglas-fir beetle outbreak develop
Detection by NMR of a "local spin-gap" in quenched CsC60
We present a 13C and 133Cs NMR investigation of the CsC60 cubic quenched
phase. Previous ESR measurements suggest that this phase is metallic, but NMR
reveals contrasting electronic behavior on the local scale. The 13C
spin-lattice relaxation time (T1) exhibits a typical metallic behavior down to
50 K, but indicates that a partial spin-gap opens for T<50 K. Unexpectedly,
133Cs NMR shows that there are two inequivalent Cs sites. For one of these
sites, the NMR shift and (T1T)^{-1} follow an activated law, confirming the
existence of a spin-gap. We ascribe this spin-gap to the occurrence of
localized spin-singlets on a small fraction of the C60 molecules.Comment: 4 figure
Dealing with paralogy in RADseq data: in silico detection and single nucleotide polymorphism validation in Robinia pseudoacacia L.
peer reviewedThe RADseq technology allows researchers to efficiently develop thousands of polymorphic
loci across multiple individuals with little or no prior information on the genome.
However, many questions remain about the biases inherent to this technology.
Notably, sequence misalignments arising from paralogy may affect the development of
single nucleotide polymorphism (SNP) markers and the estimation of genetic diversity.
We evaluated the impact of putative paralog loci on genetic diversity estimation during
the development of SNPs from a RADseq dataset for the nonmodel tree species Robinia
pseudoacacia L. We sequenced nine genotypes and analyzed the frequency of putative
paralogous RAD loci as a function of both the depth of coverage and the mismatch
threshold allowed between loci. Putative paralogy was detected in a very variable
number of loci, from 1% to more than 20%, with the depth of coverage having a major
influence on the result. Putative paralogy artificially increased the observed degree of
polymorphism and resulting estimates of diversity. The choice of the depth of coverage
also affected diversity estimation and SNP validation: A low threshold decreased
the chances of detecting minor alleles while a high threshold increased allelic dropout.
SNP validation was better for the low threshold (4×) than for the high threshold (18×)
we tested. Using the strategy developed here, we were able to validate more than 80%
of the SNPs tested by means of individual genotyping, resulting in a readily usable set
of 330 SNPs, suitable for use in population genetics applications
Slepton pair production in the POWHEG BOX
We present an implementation for slepton pair production at hadron colliders
in the POWHEG BOX, a framework for combining next-to-leading order QCD
calculations with parton-shower Monte-Carlo programs. Our code provides a SUSY
Les Houches Accord interface for setting the supersymmetric input parameters.
Decays of the sleptons and parton-shower effects are simulated with PYTHIA.
Focussing on a representative point in the supersymmetric parameter space we
show results for kinematic distributions that can be observed experimentally.
While next-to-leading order QCD corrections are sizable for all distributions,
the parton shower affects the color-neutral particles only marginally.
Pronounced parton-shower effects are found for jet distributions.Comment: 10 pages, 4 figure
Holographic Entanglement Entropy and Fermi Surfaces
The entanglement entropy in theories with a Fermi surface is known to produce
a logarithmic violation of the usual area law behavior. We explore the
possibility of producing this logarithmic violation holographically by
analyzing the IR regions of the bulk geometries dual to such theories. The
geometry of Ogawa, Takayanagi, and Ugajin is explored and shown to have a null
curvature singularity for all values of parameters, except for dynamical
critical exponent 3/2 in four dimensions. The results are extended to general
hyperscaling violation exponent. We explore strings propagating through the
singularity and show that they become infinitely excited, suggesting the
singularity is not resolved by stringy effects and may become a full-fledged
"stringularity." An Einstein-Maxwell-dilaton embedding of the nonsingular
geometry is exhibited where the dilaton asymptotes to a constant in the IR. The
unique nonsingular geometry in any given number of dimensions is proposed as a
model to study the T=0 limit of a theory with a Fermi surface.Comment: 20 pages plus appendices, 5 figures; v2 discussion clarified, results
generalized, and acknowledgments update
STAR: predicting recombination sites from amino acid sequence
BACKGROUND: Designing novel proteins with site-directed recombination has enormous prospects. By locating effective recombination sites for swapping sequence parts, the probability that hybrid sequences have the desired properties is increased dramatically. The prohibitive requirements for applying current tools led us to investigate machine learning to assist in finding useful recombination sites from amino acid sequence alone. RESULTS: We present STAR, Site Targeted Amino acid Recombination predictor, which produces a score indicating the structural disruption caused by recombination, for each position in an amino acid sequence. Example predictions contrasted with those of alternative tools, illustrate STAR'S utility to assist in determining useful recombination sites. Overall, the correlation coefficient between the output of the experimentally validated protein design algorithm SCHEMA and the prediction of STAR is very high (0.89). CONCLUSION: STAR allows the user to explore useful recombination sites in amino acid sequences with unknown structure and unknown evolutionary origin. The predictor service is available from
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