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121.
The per review system for the assessment of research proposals is widely respected by working scientists. Nevertheless two problems associated with the operation of this system by the US National Institutes of Health are identified. First the scientist has no control over which committee will review an application and it may be considered by a quite inappropriate group. Second analysis of the committee composition suggests that in some of the groups several members are not active scientists and therefore not the "peers" of the applicant. 相似文献
122.
A Childerstone H Takamatsu H Yang M Denyer RM Parkhouse 《Canadian Metallurgical Quarterly》1998,62(4):281-296
Infection of pigs with many strains of African Swine Fever Virus (ASFV) has been shown to cause a loss or marked decrease in the ability of splenocytes to respond to mitogens. These observations have been extended by cell fractionation and reconstitution experiments to show that the mitogen stimulated proliferative capacity of both the CD4+ and CD8+ T cells is affected. Similarly, monocytes which are directly infectable by virus, are functionally defective as antigen presenting cells when added to mitogen stimulated normal T cells. Interestingly, the same T cells which respond poorly in mitogenic assays can be activated by stimulation through the CD3 receptor. In contrast to the defective mitogenic response of T cells, B cell function, as assessed by stimulation through the CD40 ligand in vitro remains intact. There is no evidence for apoptosis in either the T cells or the B cells recovered from the spleens of ASFV infected animals 1-5 days following infection. Although the number of leucocytes which can be recovered from the infected spleen decreases rapidly with progression of the disease, the proportion of the different cell phenotypes remains constant. Thus decreased activity of lymphocytes in lymphoid tissue from ASFV infected animals appears to be directly attributable to infection of the monocytes. 相似文献
123.
Non-energy benefits of energy efficiency programs have been studied as early as 1993, and there have been hundreds of papers and reports published since then, many of them finding that NEB are significant. Yet many U.S. states do not include NEB in their cost-benefit analyses. This article tries to provide some insight into this mismatch between the findings of NEB research and policy by analyzing the empirical basis of such research. 相似文献
124.
Neurons in the central nucleus of the inferior colliculus (ICc) typically respond with phase-locked discharges to low rates of sinusoidal amplitude-modulated (SAM) signals and fail to phase-lock to higher SAM rates. Previous studies have shown that comparable phase-locking to SAM occurs in the dorsal nucleus of the lateral lemniscus (DNLL) and medial superior olive (MSO) of the mustache bat. The studies of MSO and DNLL also showed that the restricted phase-locking to low SAM rates is created by the coincidence of phase-locked excitatory and inhibitory inputs that have slightly different latencies. Here we tested the hypothesis that responses to SAM in the mustache bat IC are shaped by the same mechanism that shapes responses to SAM in the two lower nuclei. We recorded responses from ICc neurons evoked by SAM signals before and during the iontophoretic application of several pharmacological agents: bicuculline, a competitive antagonist for gamma-aminobutyric acid-A (GABAA) receptors; strychnine, a competitive antagonist for glycine receptors; the GABAB receptor blocker, phaclofen, and the N-methyl-D-aspartate (NMDA) receptor blocker, (-)-2-amino-5-phosphonopentanoic acid (AP5). The hypothesis that inhibition shapes responses to SAM signals in the ICc was not confirmed. In >90% of the ICc neurons tested, the range of SAM rates to which they phase-locked was unchanged after blocking inhibition with bicuculline, strychnine or phaclofen, applied either individually or in combination. We also considered the possibility that faster alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors follow high temporal rates of incoming excitation but that the slower NMDA receptors could follow only lower rates. Thus at higher SAM rates, NMDA receptors might generate a sustained excitation that "smears" the phase-locked excitation generated by the AMPA receptors. The NMDA hypothesis, like the inhibition hypothesis, was also not confirmed. In none of the cells that we tested did the application of AP5 by itself, or in combination with bicuculline, cause an increase in the range of SAM rates that evoked phase-locking. These results illustrate that the same response property, phase-locking restricted to low SAM rates, is formed in more than one way in the auditory brain stem. In the MSO and DNLL, the mechanism is coincidence of phase-locked excitation and inhibition, whereas in ICc the same response feature is formed by a different but unknown mechanism. 相似文献
125.
126.
Silicon - Al-Si based alloy matrix composites are now broadly utilized by the industrial sectors like automobile, structural, aerospace and more practical industrial applications due to its... 相似文献
127.
With increased interest in energy efficiency in recent years, energy efficiency portfolio standards (EEPS) have gained popularity in state policymaking. This analysis employed New Jersey specific data to compare two incentive based approaches to EEPS implementation: rebates and white certificates. Quantitative modeling suggests that white certificate approaches that depend on market-clearing prices generate much larger upfront incentive outlays than rebate programs. They do not however increase societal burden. Both programs overcome high upfront efficiency measure costs and both recoup the expenses over the long run. Administration costs and participation rates can affect this dynamic however and require additional research to determine which approaches are most cost effective for various energy efficiency measures. 相似文献
128.
RM. Senthamarai P. Devadas Manoharan D. Gobinath 《Construction and Building Materials》2011,25(5):2413-2419
Concrete which contains waste products as aggregate is called ‘Green’ concrete. Use of hazardous waste in concrete-making will lead to green environment and sustainable concrete technology and so such concrete can also be called as ‘Green’ concrete. Concrete made with ceramic electrical insulator waste as coarse aggregate shows good workability, compressive, tensile and flexural strengths and modulus of elasticity. Further, study of its durability will ensure greater reliability in its usage. Permeation characters are used widely to quantify durability properties of concrete. This paper presents an experimental investigation on the permeation characteristics [volume of voids and water absorption (ASTM C642-06), chloride penetration (ASTM C1202-10), and sorption] of concrete with ceramic electrical insulator waste coarse aggregate (hereafter it is called recycled aggregate concrete) of six different water–cement ratios in comparison with those of corresponding conventional concrete mixes. From the results it has been observed that there is no significant change in the basic trend of permeation characteristics of this recycled aggregate concrete when compared to the conventional concrete. This recycled aggregate concrete possesses higher permeation characteristic values than those of conventional concrete. These values decrease with decrease in water–cement ratio for both the recycled aggregate concrete and the conventional concrete. 相似文献
129.
Indentation testing is a convenient means to study mechanical properties of thin coatings. We suggest a new method to identify the viscoplastic behavior of a polymer by using the force-penetration curves during nano-indentation testing performed with two indenter shapes. During loading, the load applied by the indenter and the penetration depth have been measured. These force-penetration curves have been compared to the load computed by using the finite element method with a two dimensional software. The viscoplastic behavior of the polymer is modeled with the G'sell-Jonas law. The main particularity of this law is the modeling of the large strain-hardening at large strains. The unknown parameters of this law have been obtained by fitting computed and experimental force-penetration curves. We have identified each parameter independently of the others by taking into account the indenter tip defect. The nano-indentation tests have been performed with three strain rates and with two indenter shapes: a Berkovich indenter and a cone with a semi angle of = 30° and a tip radius. In this paper, the polymer is a polycarbonate. Several authors have made rheological tests on this polymer. The true strain-true stress curve obtained with our method is in good agreement with the compression curve. 相似文献
130.
P Mooney M Sarmiento JM Bishop N Biswas NM Cason L Dauwe J Godfrey VP Kenney R Pemper E Rojek RC Ruchti WD Shephard G Ginther RM Edelstein CP Forsyth K Gamarnik AE Kreymer RJ Lipton JM McQuade DM Potter JS Russ L Spiegel DE Johnson D Buchholz LM Cremaldi SW Delchamps HS Mao JL Rosen W Sakumoto RA Schluter SB Sontz C Winter 《Canadian Metallurgical Quarterly》1989,39(9):2494-2498