5,127 research outputs found
USING CALLING ACTIVITY TO PREDICT CALLING ACTIVITY: A CASE STUDY WITH THE ENDANGERED HOUSTON TOAD (BUFO [ANAXYRUS] HOUSTONENSIS)
Understanding anuran calling activity patterns is important for maximizing efficiency and value of call survey data collection and analyses. Previous studies have primarily focused on identifying and quantifying abiotic variables that influence anuran calling activity, and investigating relationships between calling activity and population estimates. In this study we investigated the use of a predictor pond approach to guide call survey effort. In this approach, calling activity at a subset of breeding sites (e.g., ponds) is used as a predictor of calling activity at additional breeding sites, with the goal being to minimize sampling effort while simultaneously maximizing sampling efficiency. We explored the efficiency of this approach using call survey data collected on the endangered Houston Toad (Bufo [Anaxyrus] houstonensis) at 15 known breeding ponds over 9 survey years. We found that if calling activity at 3 predictor ponds was used to decide if additional call surveys would occur at the remaining 12 ponds, we would have hypothetically correctly assumed calling activity was not occurring at non-predictor ponds on 92.1% of survey nights, and we would have hypothetically detected 93.9% of the total number of detected individuals over the 9 survey years. We found the predictor pond approach performed well in our case study, and believe it could be a valuable tool for many anuran monitoring programs
A History of Weinbau in the Lower Missouri Valley: From Dutzow to Hermann, Missouri
The thesis presented is a history focusing on the rise of German immigration, wine growing and production or Weinbau, in the lower Missouri valley from Dutzow, Missouri to Hermann, Missouri, and the connection between the nineteenth century Missouri Germans and the rise of the Missouri wine industry
Robustness of composite pulses to time-dependent control noise
We study the performance of composite pulses in the presence of time-varying
control noise on a single qubit. These protocols, originally devised only to
correct for static, systematic errors, are shown to be robust to time-dependent
non-Markovian noise in the control field up to frequencies as high as ~10% of
the Rabi frequency. Our study combines a generalized filter-function approach
with asymptotic dc-limit calculations to give a simple analytic framework for
error analysis applied to a number of composite-pulse sequences relevant to
nuclear magnetic resonance as well as quantum information experiments. Results
include examination of recently introduced concatenated composite pulses and
dynamically corrected gates, demonstrating equivalent first-order suppression
of time-dependent fluctuations in amplitude and/or detuning, as appropriate for
the sequence in question. Our analytic results agree well with numerical
simulations for realistic noise spectra with a roll-off to ,
providing independent validation of our theoretical insights.Comment: 11 pages, 4 figures, text and figures updated to published versio
Partial swing golf shots: scaled from full swing or independent technique?
During practice and competition, golfers are required to use submaximal effort to hit the ball a given distance, i.e. perform a partial shot. While the full golf swing has undergone extensive research, little has addressed partial shots and the biomechanical modifications golfers employ.
This study investigates the biomechanical changes between full and partial swings, and determines if the partial swing is a scaled version of the full swing. Using a repeated measures design, thirteen male golfers completed a minimum of 10 swings in the full and partial swing conditions, whilst club, ball, kinematic and kinetic parameters were recorded. Large and statistically significant reductions in body motion (centre of pressure ellipse: 33%, p = 0.004 , d = 2.26), combined with moderate reductions in lateral shift (25.5%, p = 0.004, d = 0.332) and smaller reductions in trunk rotation (arm to vertical at top of backswing: 14.1%, p = 0.002, d = 2.58) indicate golfers favour larger reductions in proximal measures, combined with diminished reductions as variables moved distally. Furthermore, the partial swing was not found to be a scaled version of the full swing implying a new approach to coaching practices might be considered
Large-scale Spatiotemporal Spike Patterning Consistent with Wave Propagation in Motor Cortex
Aggregate signals in cortex are known to be spatiotemporally organized as propagating waves across the cortical surface, but it remains unclear whether the same is true for spiking activity in individual neurons. Furthermore, the functional interactions between cortical neurons are well documented but their spatial arrangement on the cortical surface has been largely ignored. Here we use a functional network analysis to demonstrate that a subset of motor cortical neurons in non-human primates spatially coordinate their spiking activity in a manner that closely matches wave propagation measured in the beta oscillatory band of the local field potential. We also demonstrate that sequential spiking of pairs of neuron contains task-relevant information that peaks when the neurons are spatially oriented along the wave axis. We hypothesize that the spatial anisotropy of spike patterning may reflect the underlying organization of motor cortex and may be a general property shared by other cortical areas
Multiple duplications of yeast hexose transport genes in response to selection in a glucose-limited environment
When microbes evolve in a nutrient-limited environment, natural selection can be predicted to favor genetic changes that give cells greater access to limiting substrate. We analyzed a population of baker\u27s yeast that underwent 450 generations of glucose-limited growth. Relative to the strain used as the inoculum, the predominant cell type at the end of this experiment sustains growth at significantly lower steady-state glucose concentrations and demonstrates markedly enhanced cell yield per mole glucose, significantly enhanced high-affinity glucose transport, and greater relative fitness in pairwise competition. These changes are correlated with increased levels of mRNA hybridizing to probe generated from the hexose transport locus HXT6. Further analysis of the evolved strain reveals the existence of multiple tandem duplications involving two highly similar, high-affinity hexose transport loci, HXT6 and HXT7. Selection appears to have favored changes that result in the formation of more than three chimeric genes derived from the upstream promoter of the HXT gene and the coding sequence of HXT6. We propose a genetic mechanism to account for these changes and speculate as to their adaptive significance in the context of gene duplication as a common response of microorganisms to nutrient limitation
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Anatomic Fat Depots and Coronary Plaque Among Human Immunodeficiency Virus-Infected and Uninfected Men in the Multicenter AIDS Cohort Study.
Methods.  In a cross-sectional substudy of the Multicenter AIDS Cohort Study, noncontrast cardiac computed tomography (CT) scanning for coronary artery calcium (CAC) scoring was performed on all men, and, for men with normal renal function, coronary CT angiography (CTA) was performed. Associations between fat depots (visceral adipose tissue [VAT], abdominal subcutaneous adipose tissue [aSAT], and thigh subcutaneous adipose tissue [tSAT]) with coronary plaque presence and extent were assessed with logistic and linear regression adjusted for age, race, cardiovascular disease (CVD) risk factors, body mass index (BMI), and human immunodeficiency virus (HIV) parameters. Results.  Among HIV-infected men (n = 597) but not HIV-uninfected men (n = 343), having greater VAT was positively associated with noncalcified plaque presence (odds ratio [OR] = 1.04, P < .05), with a significant interaction (P < .05) by HIV serostatus. Human immunodeficiency virus-infected men had lower median aSAT and tSAT and greater median VAT among men with BMI <25 and 25-29.9 kg/m(2). Among HIV-infected men, VAT was positively associated with presence of coronary plaque on CTA after adjustment for CVD risk factors (OR = 1.04, P < .05), but not after additional adjustment for BMI. There was an inverse association between aSAT and extent of total plaque among HIV-infected men, but not among HIV-uninfected men. Lower tSAT was associated with greater CAC and total plaque score extent regardless of HIV serostatus. Conclusions.  The presence of greater amounts of VAT and lower SAT may contribute to increased risk for coronary artery disease among HIV-infected persons
Parity Violation, the Neutron Radius of Lead, and Neutron Stars
The neutron radius of a heavy nucleus is a fundamental nuclear-structure
observable that remains elusive. Progress in this arena has been limited by the
exclusive use of hadronic probes that are hindered by large and controversial
uncertainties in the reaction mechanism. The Parity Radius Experiment at the
Jefferson Laboratory offers an attractive electro-weak alternative to the
hadronic program and promises to measure the neutron radius of 208Pb accurately
and model independently via parity-violating electron scattering. In this
contribution we examine the far-reaching implications that such a determination
will have in areas as diverse as nuclear structure, atomic parity violation,
and astrophysics.Comment: 5 pages, 5 figures, proceedings to the PAVI06 conferenc
Insensitivity of the elastic proton-nucleus reaction to the neutron radius of 208Pb
The sensitivity--or rather insensitivity--of the elastic proton-nucleus
reaction to the neutron radius of 208Pb is investigated using a
non-relativistic impulse-approximation approach. The energy region (Tlab=500
MeV and Tlab=800 MeV) is selected so that the impulse approximation may be
safely assumed. Therefore, only free nucleon-nucleon scattering data are used
as input for the optical potential. Further, the optical potential includes
proton and neutron ground-state densities that are generated from
accurately-calibrated models. Even so, these models yield a wide range of
values (from 0.13 fm to 0.28 fm) for the poorly known neutron skin thickness in
208Pb. An excellent description of the experimental cross section is obtained
with all neutron densities. We have invoked analytic insights developed within
the eikonal approximation to understand the insensitivity of the differential
cross section to the various neutron densities. As the diffractive oscillations
of the cross sections are controlled by the matter radius of the nucleus, the
large spread in the neutron skin among the various models gets diluted into a
mere 1.5% difference in the matter radius. This renders ineffective the elastic
reaction as a precision tool for the measurement of neutron radii.Comment: 17 pages with 5 figure
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Short-Term Insulin Requirements Following Gastric Bypass Surgery in Severely Obese Women with Type 1 Diabetes
Background: In severely obese type 2 diabetes patients, gastric bypass surgery (GB) reduces body mass index (BMI) and hemoglobin A1c (HbA1c) and allows reduced doses of insulin and other medications. Data regarding the effects of GB on severely obese patients with type 1 diabetes are limited. Methods: Severely obese women with type 1 diabetes (n = 9) were studied immediately before and after GB (7.7 ± 5.8 weeks, mean ± SD). Results: On average, GB reduced mean BMI by 11 % and mean HbA1c by 0.9 % (from 8.0 to 7.1 %), with a parallel 38 % decrease in basal insulin requirements (expressed per kilogram of body weight). Conclusion: GB rapidly decreased BMI, HbA1c, and insulin requirements in severely obese women with type 1 diabetes. However, physiologic insulin replacement remains necessary in patients with type 1 diabetes
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