496 research outputs found
LabView Interface for School-Network DAQ Card
A low-cost DAQ card has been developed for school-network cosmic ray detector
projects, providing digitized data from photomultiplier tubes via a standard
serial interface. To facilitate analysis of these data and to provide students
with a starting point for custom readout systems, a model interface has been
developed using the National Instruments LabVIEW(R) system. This user-friendly
interface allows one to initialize the trigger coincidence conditions for
data-taking runs and to monitor incoming or pre-recorded data sets with
updating singles- and coincidence-rate plots and other user-selectable
histograms.Comment: 4 pages, 6 figures. Presented as Paper NS26-119 at IEEE-NSS 2003,
Portland, OR, by R. J. Wilke
Effects of Bolus vs. Metered Rehydration Rates on Fluid Retention and Hydration Efficiency using 150% Fluid Replacement.
Effects of Bolus vs. Metered Rehydration Rates on Fluid Retention and Hydration Efficiency using 150% Fluid Replacement. Authors: Jared Graham (Masters), Tiffany Newcomb (Masters), Nathan Frischman (Undergraduate), Eric Jones (Ph D) Department of Kinesiology and Health Science Stephen F. Austin State University Nacogdoches TX. 75962 Purpose: This study assessed differences in urine production using bolus vs. metered ingestion fluid consumption during post-exercise rehydration. Methods: Using light to moderate activity in an environmentally controlled chamber (35°C), 9 male subjects were dehydrated by ~ 2% body weight. Following dehydration, counterbalanced rehydration trials (water) were performed in which two different methods of rehydrating; metered consumption (18.75% of total volume every 30mins for 4 hours) and bolus consumption (150% of total volume within 1 hour) were utilized. Urine production was evaluated and reported each hour during an eight-hour period following exercise to evaluate net fluid balance and hydration efficiency (fluid consumed vs. fluid retained). Results: Paired samples T-test revealed no significant differences (p=.94) between the two rehydration methods for hydration efficiency (bolus 41.5% vs. metered 42%) or net fluid balance (mean urine production: bolus 1347ml vs. metered 1337ml). Conclusions: Previous research using 100% fluid replacement (water) has revealed that metered consumption improves hydration efficiency and net fluid balance. However, the current findings suggest that any advantages gained through varying fluid consumption rates may be nullified by larger total rehydration volumes (150%)
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Crustal inheritance and a top-down control on arc magmatism at Mount St. Helens
In a subduction zone, the volcanic arc marks the location where magma, generated via flux melting in the mantle wedge, migrates through the crust and erupts. While the location of deep magma broadly defines the arc position, here we argue that crustal structures, identified in geophysical data from the Washington Cascades magmatic arc, are equally important in controlling magma ascent and defining the spatial distribution and compositional variability of erupted material. As imaged by a three-dimensional resistivity model, a broad lower-crustal mush zone containing 3-10% interconnected melt underlies this segment of the arc, interpreted to episodically feed upper-crustal magmatic systems and drive eruptions. Mount St. Helens is fed by melt channeled around a mid-Tertiary batholith also imaged in the resistivity model and supported by potential-field data. Regionally, volcanism and seismicity are almost exclusive of the batholith, while at Mount St. Helens, along its margin, the ascent of viscous felsic melt is enabled by deep-seated metasedimentary rocks. Both the anomalous forearc location and composition of St. Helens magmas are products of this zone of localized extension along the batholith margin. This work is a compelling example of inherited structural control on local stress state and magmatism
LHC Coverage of RPV MSSM with Light Stops
We examine the sensitivity of recent LHC searches to signatures of
supersymmetry with R-parity violation (RPV). Motivated by naturalness of the
Higgs potential, which would favor light third-generation squarks, and the
stringent LHC bounds on spectra in which the gluino or first and second
generation squarks are light, we focus on scenarios dominated by the pair
production of light stops. We consider the various possible direct and cascade
decays of the stop that involve the trilinear RPV operators. We find that in
many cases, the existing searches exclude stops in the natural mass range and
beyond. However, typically there is little or no sensitivity to cases dominated
by UDD operators or LQD operators involving taus. We propose several ideas for
searches which could address the existing gaps in experimental coverage of
these signals.Comment: 41 pages, 12 figures; v2: included new searches (see footnote 10),
minor corrections and improvement
Simplified Models for LHC New Physics Searches
This document proposes a collection of simplified models relevant to the
design of new-physics searches at the LHC and the characterization of their
results. Both ATLAS and CMS have already presented some results in terms of
simplified models, and we encourage them to continue and expand this effort,
which supplements both signature-based results and benchmark model
interpretations. A simplified model is defined by an effective Lagrangian
describing the interactions of a small number of new particles. Simplified
models can equally well be described by a small number of masses and
cross-sections. These parameters are directly related to collider physics
observables, making simplified models a particularly effective framework for
evaluating searches and a useful starting point for characterizing positive
signals of new physics. This document serves as an official summary of the
results from the "Topologies for Early LHC Searches" workshop, held at SLAC in
September of 2010, the purpose of which was to develop a set of representative
models that can be used to cover all relevant phase space in experimental
searches. Particular emphasis is placed on searches relevant for the first
~50-500 pb-1 of data and those motivated by supersymmetric models. This note
largely summarizes material posted at http://lhcnewphysics.org/, which includes
simplified model definitions, Monte Carlo material, and supporting contacts
within the theory community. We also comment on future developments that may be
useful as more data is gathered and analyzed by the experiments.Comment: 40 pages, 2 figures. This document is the official summary of results
from "Topologies for Early LHC Searches" workshop (SLAC, September 2010).
Supplementary material can be found at http://lhcnewphysics.or
A community-maintained standard library of population genetic models
The explosion in population genomic data demands ever more complex modes of analysis, and increasingly, these analyses depend on sophisticated simulations. Recent advances in population genetic simulation have made it possible to simulate large and complex models, but specifying such models for a particular simulation engine remains a difficult and error-prone task. Computational genetics researchers currently re-implement simulation models independently, leading to inconsistency and duplication of effort. This situation presents a major barrier to empirical researchers seeking to use simulations for power analyses of upcoming studies or sanity checks on existing genomic data. Population genetics, as a field, also lacks standard benchmarks by which new tools for inference might be measured. Here, we describe a new resource, stdpopsim, that attempts to rectify this situation. Stdpopsim is a community-driven open source project, which provides easy access to a growing catalog of published simulation models from a range of organisms and supports multiple simulation engine backends. This resource is available as a well-documented python library with a simple command-line interface. We share some examples demonstrating how stdpopsim can be used to systematically compare demographic inference methods, and we encourage a broader community of developers to contribute to this growing resource.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]
Higher pre-infection vitamin E levels are associated with higher mortality in HIV-1-infected Kenyan women: a prospective study
Background: Low vitamin E levels are often found in HIV-1 infection, and studies have suggested that higher levels may decrease the risk of disease progression. However, vitamin E supplementation has also been reported to increase CCR5 expression, which could increase HIV-
1 replication. We hypothesized that vitamin E levels at HIV-1 acquisition may influence disease progression.
Methods: Vitamin E status was measured in stored samples from the last pre-infection visit for 67 Kenyan women with reliably estimated dates of HIV-1 acquisition. Regression analyses were used
to estimate associations between pre-infection vitamin E and plasma viral load, time to CD4 count less than 200 cells/[micro]L, and mortality.
Results: After controlling for potential confounding factors, each 1 mg/L increase in pre-infection vitamin E was associated with 0.08 log[sub]10 copies/mL (95% CI -0.01 to +0.17) higher set point viral load and 1.58-fold higher risk of mortality (95% CI 1.15�2.16). The association between higher preinfection vitamin E and mortality persisted after adjustment for set point viral load (HR 1.55, 95% CI 1.13�2.13).
Conclusion: Higher pre-infection vitamin E levels were associated with increased mortality. Further research is needed to elucidate the role vitamin E plays in HIV-1 pathogenesis.This research was supported by National Institutes of Health grants AI-43844 and AI-38518 (all authors), and Fogarty International Center grant D43 TW000007 (SMG)
LEECH: A 100 Night Exoplanet Imaging Survey at the LBT
In February 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began
its 100-night campaign from the Large Binocular Telescope atop Mount Graham in
Arizona. LEECH nearly complements other high-contrast planet imaging efforts by
observing stars in L' band (3.8 microns) as opposed to the shorter wavelength
near-infrared bands (1-2.3 microns). This part of the spectrum offers deeper
mass sensitivity for intermediate age (several hundred Myr-old) systems, since
their Jovian-mass planets radiate predominantly in the mid-infrared. In this
proceedings, we present the science goals for LEECH and a preliminary contrast
curve from some early data.Comment: IAUS 299 Proceeding
Subterranean, herbivore-induced plant volatile increases biological control activity of multiple beneficial nematode species in distinct habitats
While the role of herbivore-induced volatiles in plant-herbivore-natural enemy interactions is well documented aboveground, new evidence suggests that belowground volatile emissions can protect plants by attracting entomopathogenic nematodes (EPNs). However, due to methodological limitations, no study has previously detected belowground herbivore-induced volatiles in the field or quantified their impact on attraction of diverse EPN species. Here we show how a belowground herbivore-induced volatile can enhance mortality of agriculturally significant root pests. First, in real time, we identified pregeijerene (1,5-dimethylcyclodeca-1,5,7-triene) from citrus roots 9-12 hours after initiation of larval Diaprepes abbreviatus feeding. This compound was also detected in the root zone of mature citrus trees in the field. Application of collected volatiles from weevil-damaged citrus roots attracted native EPNs and increased mortality of beetle larvae (D. abbreviatus) compared to controls in a citrus orchard. In addition, field applications of isolated pregeijerene caused similar results. Quantitative real-time PCR revealed that pregeijerene increased pest mortality by attracting four species of naturally occurring EPNs in the field. Finally, we tested the generality of this root-zone signal by application of pregeijerene in blueberry fields; mortality of larvae (Galleria mellonella and Anomala orientalis) again increased by attracting naturally occurring populations of an EPN. Thus, this specific belowground signal attracts natural enemies of widespread root pests in distinct agricultural systems and may have broad potential in biological control of root pests.info:eu-repo/semantics/publishedVersio
Transcriptome characterization and polymorphism detection between subspecies of big sagebrush (Artemisia tridentata)
<p>Abstract</p> <p>Background</p> <p>Big sagebrush (<it>Artemisia tridentata</it>) is one of the most widely distributed and ecologically important shrub species in western North America. This species serves as a critical habitat and food resource for many animals and invertebrates. Habitat loss due to a combination of disturbances followed by establishment of invasive plant species is a serious threat to big sagebrush ecosystem sustainability. Lack of genomic data has limited our understanding of the evolutionary history and ecological adaptation in this species. Here, we report on the sequencing of expressed sequence tags (ESTs) and detection of single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers in subspecies of big sagebrush.</p> <p>Results</p> <p>cDNA of <it>A. tridentata </it>sspp. <it>tridentata </it>and <it>vaseyana </it>were normalized and sequenced using the 454 GS FLX Titanium pyrosequencing technology. Assembly of the reads resulted in 20,357 contig consensus sequences in ssp. <it>tridentata </it>and 20,250 contigs in ssp. <it>vaseyana</it>. A BLASTx search against the non-redundant (NR) protein database using 29,541 consensus sequences obtained from a combined assembly resulted in 21,436 sequences with significant blast alignments (≤ 1e<sup>-15</sup>). A total of 20,952 SNPs and 119 polymorphic SSRs were detected between the two subspecies. SNPs were validated through various methods including sequence capture. Validation of SNPs in different individuals uncovered a high level of nucleotide variation in EST sequences. EST sequences of a third, tetraploid subspecies (ssp. <it>wyomingensis</it>) obtained by Illumina sequencing were mapped to the consensus sequences of the combined 454 EST assembly. Approximately one-third of the SNPs between sspp. <it>tridentata </it>and <it>vaseyana </it>identified in the combined assembly were also polymorphic within the two geographically distant ssp. <it>wyomingensis </it>samples.</p> <p>Conclusion</p> <p>We have produced a large EST dataset for <it>Artemisia tridentata</it>, which contains a large sample of the big sagebrush leaf transcriptome. SNP mapping among the three subspecies suggest the origin of ssp. <it>wyomingensis </it>via mixed ancestry. A large number of SNP and SSR markers provide the foundation for future research to address questions in big sagebrush evolution, ecological genetics, and conservation using genomic approaches.</p
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