1,406 research outputs found
Charmonium mass splittings at the physical point
We present results from an ongoing study of mass splittings of the lowest
lying states in the charmonium system. We use clover valence charm quarks in
the Fermilab interpretation, an improved staggered (asqtad) action for sea
quarks, and the one-loop, tadpole-improved gauge action for gluons. This study
includes five lattice spacings, 0.15, 0.12, 0.09, 0.06, and 0.045 fm, with two
sets of degenerate up- and down-quark masses for most spacings. We use an
enlarged set of interpolation operators and a variational analysis that permits
study of various low-lying excited states. The masses of the sea quarks and
charm valence quark are adjusted to their physical values. This large set of
gauge configurations allows us to extrapolate results to the continuum physical
point and test the methodology.Comment: 7 pp, 6 figs, Lattice 201
Spatial Resolution of a Micromegas-TPC Using the Charge Dispersion Signal
The Time Projection Chamber (TPC) for the International Linear Collider will
need to measure about 200 track points with a resolution close to 100 m. A
Micro Pattern Gas Detector (MPGD) readout TPC could achieve the desired
resolution with existing techniques using sub-millimeter width pads at the
expense of a large increase in the detector cost and complexity. We have
recently applied a new MPGD readout concept of charge dispersion to a prototype
GEM-TPC and demonstrated the feasibility of achieving good resolution with pads
similar in width to the ones used for the proportional wire TPC. The charge
dispersion studies were repeated with a Micromegas TPC amplification stage. We
present here our first results on the Micromegas-TPC resolution with charge
dispersion. The TPC resolution with the Micromegas readout is compared to our
earlier GEM results and to the resolution expected from electron statistics and
transverse diffusion in a gaseous TPC.Comment: 5 pages, 8 figures, to appar in the Proceedings of the 2005
International Linear Collider Workshop (LCWS05), Stanford, 18-22 March 200
BATS OF THE WEST INDIAN ISLAND OF DOMINICA: NATURAL HISTORY, AREOGRAPHY, AND TROPHIC STRUCTURE
Because the islands in the Caribbean long have interested students of mammals and zoogeography, considerable information has been published concerning the biology of the Antillean mammalian fauna in the past three decades (Jones and Schwartz, 1967; Schwartz and Jones, 1967; Koopman, 1968, 1989; Jones and Phillips, 1970, 1976; Varona, 1974; Baker and Genoways, 1978; Baker et al., 1978; Swanepoel and Genoways, 1978; Jones and Baker, 1979; Silva Taboada, 1979; Baker et al., 1984; Eshelman and Morgan, 1985; Buden, 1986; Griffiths and Klingener, 1988; Jones, 1989; Masson et al., 1990; Pederson et al., 1996; Genoways et al., 1998). This increasing interest in the systematics and zoogeography of mammals in the region has involved both studies in the field and re-examination of collections made in earlier years. One problem facing investigators who attempt to assess the faunal relationships of the Antilles is the fact that natural conditions on most islands have been altered significantly as a result of early settlement, first by Ameridians, then by Europeans beginning in the 1500s. Changes wrought by agricultural practices have destroyed much of the original environment, and introduction on many islands of the mongoose (Herpestes javanicus) as a supposed means of controlling introduced rats (both Rattus norvegicus and R. rattus) has disturbed natural conditions
Characteristics of lesser prairie-chicken (Tympanuchus pallidicinctus) long-distance movements across their distribution
Citation: Earl, J. E., Fuhlendorf, S. D., Haukos, D., Tanner, A. M., Elmore, D., & Carleton, S. A. (2016). Characteristics of lesser prairie-chicken (Tympanuchus pallidicinctus) long-distance movements across their distribution. Ecosphere, 7(8). doi:10.1002/(ISSN)2150-8925Long-distance movements are important adaptive behaviors that contribute to population, community, and ecosystem connectivity. However, researchers have a poor understanding of the characteristics of long-distance movements for most species. Here, we examined long-distance movements for the lesser prairie-chicken (Tympanuchus pallidicinctus), a species of conservation concern. We addressed the following questions: (1) At what distances could populations be connected? (2) What are the characteristics and probability of dispersal movements? (3) Do lesser prairie-chickens display exploratory and round-trip movements? (4) Do the characteristics of long-distance movements vary by site? Movements were examined from populations using satellite GPS transmitters across the entire distribution of the species in New Mexico, Oklahoma, Kansas, and Colorado. Dispersal movements were recorded up to 71 km net displacement, much farther than hitherto recorded. These distances suggest that there may be greater potential connectivity among populations than previously thought. Dispersal movements were displayed primarily by females and had a northerly directional bias. Dispersal probabilities ranged from 0.08 to 0.43 movements per year for both sexes combined, although these movements averaged only 16 km net displacement. Lesser prairie-chickens displayed both exploratory foray loops and round-trip movements. Half of round-trip movements appeared seasonal, suggesting a partial migration in some populations. None of the long-distance movements varied by study site. Data presented here will be important in parameterizing models assessing population viability and informing conservation planning, although further work is needed to identify landscape features that may reduce connectivity among populations. © 2016 Earl et al
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Exploring Item Order in Anxiety-Related Constructs: Practical Impacts of Serial Position
The present study was designed to test for item order effects by measuring four distinct constructs that contribute substantively to anxiety-related psychopathology (i.e., anxiety sensitivity, fear of negative evaluation, injury/illness sensitivity, and intolerance of uncertainty). Participants (n = 999; 71% women) were randomly assigned to complete measures for each construct presented in one of two modalities: (a) items presented cohesively as measures or (b) items presented randomly interspersed with one another. The results suggested that item order had a relatively small impact on item endorsement, response patterns, and reliabilities. The small impact was such that item order appears unlikely to influence clinical decisions related to these measures. These findings not only have implications for these and other similar measures, but further inform a long-standing debate about whether item grouping is a substantial concern in measurement. Accessed 6,950 times on https://pareonline.net from April 21, 2012 to December 31, 2019. For downloads from January 1, 2020 forward, please click on the PlumX Metrics link to the right
Infrared Imaging of Capella with the IOTA Closure Phase Interferometer
We present infrared aperture synthesis maps produced with the upgraded IOTA
interferometer. Michelson interferograms on the close binary system Capella
(Alpha Aur) were obtained in the H-band between 2002 November 12 and 16 using
the IONIC3 beam combiner. With baselines of 15m < B < 38m, we were able to
determine the relative position of the binary components with milliarcsecond
(mas) precision and to track their movement along the approx. 14 degree arc
covered by our observation run. We briefly describe the algorithms used for
visibility and closure phase estimation. Three different Hybrid Mapping and
Bispectrum Fitting techniques were implemented within one software framework
and used to reconstruct the source brightness distribution. By dividing our
data into subsets, the system could be mapped at three epochs, revealing the
motion of the stars. The precise position of the binary components was also
determined with model fits, which in addition revealed I_Aa/I_Ab=1.49 +/- 0.10
and apparent stellar uniform-disk (UD) diameters of Theta_Aa=8.9 +/- 0.6 mas
and Theta_Ab=5.8 +/- 0.8 mas.
To improve the u, v-plane coverage, we compensated this orbital motion by
applying a rotation-compensating coordinate transformation. The resulting
model-independent map with a beam size of 5.4 x 2.6 mas allows the resolution
of the stellar surfaces of the Capella giants themselves.Comment: Accepted by the Astronomical Journal (2005-03-21
Comparison of classical multi-locus sequence typing software for next-generation sequencing data
Multi-locus sequence typing (MLST) is a widely used method for categorizing bacteria. Increasingly, MLST is being performed using next-generation sequencing (NGS) data by reference laboratories and for clinical diagnostics. Many software applications have been developed to calculate sequence types from NGS data; however, there has been no comprehensive review to date on these methods. We have compared eight of these applications against real and simulated data, and present results on: (1) the accuracy of each method against traditional typing methods, (2) the performance on real outbreak datasets, (3) the impact of contamination and varying depth of coverage, and (4) the computational resource requirements
An examination of the precipitation delivery mechanisms for Dolleman Island, eastern Antarctic Peninsula
Copyright @ 2004 Wiley-BlackwellThe variability of size and source of significant precipitation events were studied at an Antarctic ice core drilling site: Dolleman Island (DI), located on the eastern coast of the Antarctic Peninsula. Significant precipitation events that occur at DI were temporally located in the European Centre for Medium-Range Weather Forecasting (ECMWF) reanalysis data set, ERA-40. The annual and summer precipitation totals from ERA-40 at DI both show significant increases over the reanalysis period. Three-dimensional backwards air parcel trajectories were then run for 5 d using the ECMWF ERA-15 wind fields. Cluster analyses were performed on two sets of these backwards trajectories: all days in the range 1979–1992 (the climatological time-scale) and a subset of days when a significant precipitation event occurred. The principal air mass sources and delivery mechanisms were found to be the Weddell Sea via lee cyclogenesis, the South Atlantic when there was a weak circumpolar trough (CPT) and the South Pacific when the CPT was deep. The occurrence of precipitation bearing air masses arriving via a strong CPT was found to have a significant correlation with the southern annular mode (SAM); however, the arrival of air masses from the same region over the climatological time-scale showed no such correlation. Despite the dominance in both groups of back trajectories of the westerly circulation around Antarctica, some other key patterns were identified. Most notably there was a higher frequency of lee cyclogenesis events in the significant precipitation trajectories compared to the climatological time-scale. There was also a tendency for precipitation trajectories to come from more northerly latitudes, mostly from 50–70°S. The El Niño Southern Oscillation (ENSO) was found to have a strong influence on the mechanism by which the precipitation was delivered; the frequency of occurrence of precipitation from the east (west) of DI increased during El Niño (La Niña) events
Characterization of muscle in OI Model mice
Abstract only availableOsteogenesis imperfecta (OI) is a congenital connective tissue disorder characterized by decreased bone mineral density and increased bone fragility and susceptibility to fracture. In addition to skeletal fragility, patients with OI reportedly have muscle weakness although currently no systematic evaluation of muscle function or morphology in humans or animal models of the disease has been performed. Normal type I collagen is coded for two genes located on different chromosomes: COL1A1 and COL1A2. The oim/oim mouse is homozygous for a null mutation in the COL1A2 gene and is a phenocopy of human type III OI (severe disease phenotype). Heterozygous mice (oim/+) harbor the null mutation in only one allele of the COL1A2 gene and model human patients with type I OI (mild disease phenotype). We wanted to determine whether the reported muscle weakness in OI patients is due to a muscle pathology. We analyzed the muscle mass, fiber morphology, and cross-sectional area of muscles fibers of the hind limb muscles (quadriceps, gastrocnemius, plantaris, tibialis anterior and soleus), as well as the fiber type composition of the soleus muscle of wildtype (wt), heterozygous (oim/+), and homozygous (oim/oim) mice. Our results demonstrate that the muscle mass/body mass, fiber morphology, cross-sectional area of hindlimb muscles, as well as fiber type composition of the soleus muscle of oim, oim/+ relative to wt (+/+) mouse muscles were not significantly different between the genotypes. We correlated our morphologic findings with a functional contractile assay and determined that muscle tension-force generation and nerve conduction are not impaired in oim/oim or oim/+ mice. These findings suggest that oim and oim/+ mice do not have inherent muscle pathology. This knowledge is important in our ultimate understanding of skeletal muscle in OI model mice and ultimately, humans with this disease.Life Sciences Undergraduate Research Opportunity Progra
DRESS induced by amoxicillin-clavulanate in two pediatric patients confirmed by lymphocyte toxicity assay
Background: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but serious delayed hypersensitivity reaction that can be caused by antibiotic exposure. The reaction typically develops in 2 to 6 weeks. The pathophysiology is thought to involve toxic drug metabolites acting as a hapten, triggering a systemic response. The diagnosis is made clinically but can be confirmed using assays such as the lymphocyte toxicity assay (LTA), which correlates cell death upon exposure to drug metabolites with susceptibility to hypersensitivity reactions. Case presentations: Case 1 involves a previously healthy 11-month-old male with first exposure to amoxicillin-clavulanate, prescribed for seven days to treat a respiratory infection. The patient developed DRESS fourteen days after starting the drug and was successfully treated with corticosteroids. LTA testing confirmed patient susceptibility to hypersensitivity reactions with amoxicillin-clavulanate. Parental samples were also tested, showing both maternal and paternal susceptibility. Neither parent reported prior hypersensitivity reactions. Lifelong penicillin avoidance for the patient was advised along with the notation in medical records of penicillin allergy. The parents were advised to avoid penicillin class antibiotics and be monitored closely for DRESS if they are exposed. Case 2 involves an 11-year-old female with atopic dermatitis with first exposure to amoxicillin-clavulanate, prescribed for ten days to treat a secondary bacterial skin infection. She developed DRESS eleven days after starting antibiotics and was successfully treated with corticosteroids. LTA testing confirmed patient susceptibility to hypersensitivity reactions with amoxicillin-clavulanate. Maternal samples were also tested and showed sensitivity. The mother reported no prior hypersensitivity reactions. Lifelong penicillin avoidance for the patient was advised along with the notation in medical records of penicillin allergy. Conclusions: Amoxicillin-clavulanate is a commonly used antibiotic and the cases we have described suggest that it should be recognized as a potential cause of DRESS in pediatric patients. Furthermore, these cases contribute to current literature supporting that there may be a shorter latent period in DRESS induced by antibiotics. We have also shown that the LTA can be a helpful tool to confirm DRESS reactions, and that testing may have potential implications for family members
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