Hunters are a fundamental component of northern bobwhite quail conservation

Hunters have been a fundamental component of northern bobwhite quail conservation for most of the past century. Bobwhite quail hunters funded the first modern comprehensive life history study of a wild vertebrate in the 1920s to understand causes responsible for population declines. This investigation identified a causal link between frequent applications of prescribed fire and persistence of bobwhite quail populations in the Southeastern United States, and provided the foundation for contemporary fire ecology science. Since then, hunters in the Southeastern and Midwestern United States have funded numerous other bobwhite quail research and conservation efforts. Research and conservation efforts funded by quail hunters in Texas continue to be especially notable. Non-governmental organizations, and academia, as well as state and federal wildlife agencies have been the conduits for efforts to sustain bobwhite quail populations because predominant land uses no longer support bobwhite quail.     

Modelling and traceability for computationally-intensive precision engineering and metrology

In contrast to measurements of the dimensions of machined parts realized by machine tools and characterized by CMMs, software results are not fully traceable and certified. Indeed, a computer is not a perfect machine and binary encoding of real numbers leads to rounding of successive intermediate calculations that may lead to globally false results. This is the case for poor implementations and poorly conditioned algorithms. Therefore, accurate geometric modelling and implementations will be detailed. Based on the works of National Metrology Institutes, the problem of software traceability will also be discussed. Some prospects for this complex task will finally be suggested.     

Azotetrazolylfurazan and Nitrogenous Salt Derivatives

The synthesis of (E)‐1,2‐bis(4‐(1H‐tetrazol‐5‐yl)‐1,2,5‐oxadiazol‐3‐yl)diazene (AzTF) and its high nitrogen salts is described. Compounds were tested for sensitivity to impact, spark, and friction and heats of formation were determined through bomb calorimetry. The calorimetry results coupled with density measurements by gas pychnometry were used to predict explosive output using the Cheetah thermochemical code. Of the four compounds tested AzTF itself has the most promise as an explosive due to TATB‐like performance and high thermal stability, while the triaminoguanidinium salt (TAG₂AzTF) may find favor as a high‐nitrogen gas generant in regard to the low overall sensitivity and very high nitrogen content of the molecule.     

Do small lapses predict relapse to smoking behavior under bupropion treatment?

Although bupropion is known to be an effective aid to smoking cessation, little is known about its mode of action. In the present study we tested the hypothesis that bupropion reduces the likelihood that a smoking lapse, or slip, leads to a subsequent relapse. This hypothesis was tested in the context of a clinical trial of bupropion as a smoking cessation aid, using Cox regression and representing lapse history as a discrete time-varying covariate. Bupropion treatment reduced the probability of relapse during the treatment phase (hazard ratio, or HR=.421, p< or =.000) but not during the follow-up phase (end of treatment to 6 months, HR=.896, p< or=.67). As anticipated, having small lapses during treatment contributed to or predicted subsequent relapse, both during treatment (HR=2.897, p< or =.000) and during follow-up (HR=2.320, p< or=.008). Although an interaction was found between drug treatment and lapse history in predicting subsequent failure during the treatment phase, the finding suggested that drug slightly increased the effect of lapse on eventual failure during treatment (HR=1.706, p相似文献   

Probabilistic model of fatigue fracture of carbon nanostructures

Presented evaluation of risk of fatigue fracture of carbon nanostructures (CN) is based on: (a) the criterion of the threshold of the dissipated energy of tensile stresses, and (b) simulation of stochastic character of fracture by the failures in queueing system. The assessments of probability of fatigue fracture of CN in conditions of uniaxial tension, plane torsion and uniaxial compression are done.     

Macrophage and myofibroblast involvement in ischemic acute renal failure is attenuated by endothelin receptor antagonists

BACKGROUND: Endothelin (ET) may be a mediator of injury following ischemia-induced acute renal failure (ARF). ET receptor (ETR) antagonists have been reported to increase survival rates and lower serum creatinines when administered postrenal ischemia-reperfusion injury in the rat. Renal cellular and extracellular matrix responses to this therapy have not been addressed. METHODS: We investigated the use of ETR antagonists, PD 156707 (ETA) and SB 209670 (ETA and ETB) in the treatment of sublethal postischemic ARF. The right kidney of female Sprague-Dawley rats weighing approximately 200 g was removed. After five days, the left renal pedicle was occluded for 45 minutes. Twenty-four hours after renal ischemia, one of two ETR antagonists, PD 156707 (N = 7) or SB 209670 (N = 8), was administered. Experimental animals were compared with an ischemic group receiving only saline (N = 9). Three nephrectomized groups that did not undergo ischemia but that received infusions of saline (N = 6), PD 156707 (N = 6), and SB 209670 (N = 6), respectively, were also studied. Animals were sacrificed one week postischemia. Quantitation of monocytes and macrophages (Mo/Mphi), alpha-smooth muscle actin-positive myofibroblasts, and collagens type III and IV was performed by immunohistochemical staining. Cell kinetics were examined by staining for apoptosis with terminal deoxyuridine triphosphate (dUTP) nick end labeling and for proliferation with proliferating cell nuclear antigen. RESULTS: All ischemic groups of rats initially developed raised serum creatinine levels; however, no significant difference was observed between the groups (Kruskal-Wallis). Creatinines returned to preischemic values in all groups by the time of sacrifice. No significant difference in kidney weights or body weights was found between groups. Histologically, infiltration of Mo/Mphi was significantly reduced in groups treated with ETR antagonists (P < 0.001). The presence of myofibroblasts was also significantly reduced in the antagonist-treated groups (P < 0. 001). This was also paralleled by reduced quantities of collagen IV in the treated rat groups (P < 0.001). The interstitial area was also significantly greater in the saline group (P < 0.001). The amount of collagen III did not significantly differ between rat groups. Apoptosis was reduced (P < 0.001) by treatment with ETR antagonists, whereas proliferation was enhanced (P < 0.005). All non-ischemic groups showed no variation in any parameter studied at this time point. CONCLUSIONS: Treatment of ischemic ARF in the rat with ETR antagonists PD 156707 and SB 209670 attenuated cellular infiltration and matrix accumulation. An advantage of one antagonist over the other could not be determined in this study. The marked discrepancy between function and pathology (former unchanged, latter markedly improved) may be due to the time frame of this experiment, and longer outcome measures need to be assessed.     

The sympathetic nervous system''s role in regulating blood pressurevariability

This article focuses on how sympathetic nerve activity (SNA) contributes to the variability seen in blood pressure. Specifically, it examines the following questions: why do oscillations occur at certain frequencies, why do only certain frequencies of oscillations in SNA induce oscillations in the vasculature, and what may be the functional purpose of these oscillations