971 resultados para Ricks, Lawrence
Resumo:
In this article, we present an exact theoretical analysis of an system, with arbitrary distribution of relative deadline for the end of service, operated under the first come first served scheduling policy with exact admission control. We provide an explicit solution to the functional equation that must be satisfied by the workload distribution, when the system reaches steady state. We use this solution to derive explicit expressions for the loss ratio and the sojourn time distribution. Finally, we compare this loss ratio with that of a similar system operating without admission control, in the cases of some common distributions of the relative deadline.
Resumo:
Lymphatic filariasis is the second leading cause of permanent long-term disability globally and control of this disease needs efficient diagnostic methods. In this study, abundantly expressing microfilarial sheath protein (Shp-1) from Brugia malayi was characterized as a filarial diagnostic candidate using samples from different clinical population. Monoclonal antibodies were developed against E. coil expressed recombinant Shp-1 in order to assess its efficiency in filarial antigen detection assay system. Endemic Normal (EN, n = 170), asymptomatic microfilaeremics (MF, n = 65), symptomatic chronic pathology (CP, n = 45) and non endemic normal (NEN, n = 10) sera were analyzed by antigen capture enzyme-linked immunosorbent assay. Of the 290 individuals, all MF individuals (both brugian and bancroftian) were positive in this assay followed by CP and EN. When compared with SXP-1 and Og4C3 antigen assays, all assays detected Wb MF correctly, Bm MF was detected by Shp-1 and SXP-1 assays, and only Shp-1 was able to detect EN (12%) and CP (29%). Results showed that this assay may be useful for monitoring prior to mass drug administration. (c) 2014 Elsevier Inc. All rights reserved.
Resumo:
Flexray is a high speed communication protocol designed for distributive control in automotive control applications. Control performance not only depends on the control algorithm but also on the scheduling constraints in communication. A balance between the control performance and communication constraints must required for the choice of the sampling rates of the control loops in a node. In this paper, an optimum sampling period of control loops to minimize the cost function, satisfying the scheduling constraints is obtained. An algorithm to obtain the delay in service of each task in a node of the control loop in the hyper period has been also developed. (C) 2015 The Authors. Published by Elsevier B.V.
Resumo:
We isolated an 8 kDa mycobacterial hypothetical protein, Rv3423.1, from the chromatin of human macrophages infected with Mycobacterium tuberculosis H37Rv. Bioinformatics predictions followed by in vitro biochemical assays with purified recombinant protein showed that Rv3423.1 is a novel histone acetyltransferase that acetylates histone H3 at the K9/K14 positions. Transient transfection of macrophages containing GFP-tagged histone H1 with RFP-tagged Rv3423.1 revealed that the protein co-localizes with the chromatin in the nucleus. Co-immunoprecipitation assays confirmed that the Rv3423.1-histone interaction is specific. Rv3423.1 protein was detected in the culture filtrate of virulent but not avirulent M. tuberculosis. Infection of macrophages with recombinant Mycobacterium smegmatis constitutively expressing Rv3423.1 resulted in a significant increase in the number of intracellular bacteria. However, the protein did not seem to offer any growth advantage to free-living recombinant M. smegmatis. It is highly likely that, by binding to the host chromatin, this histone acetyltransferase from M. tuberculosis may manipulate the expression of host genes involved in anti-inflammatory responses to evade clearance and to survive in the intracellular environment.
Resumo:
Drosophila germ-band extension (GBE) is an example of the convergence and extension movements that elongate and narrow embryonic tissues. To understand the collective cell behaviours underlying tissue morphogenesis, we have continuously quantified cell intercalation and cell shape change during GBE. We show that the fast, early phase of GBE depends on cell shape change in addition to cell intercalation. In antero-posterior patterning mutants such as those for the gap gene Krüppel, defective polarized cell intercalation is compensated for by an increase in antero-posterior cell elongation, such that the initial rate of extension remains the same. Spatio-temporal patterns of cell behaviours indicate that an antero-posterior tensile force deforms the germ band, causing the cells to change shape passively. The rate of antero-posterior cell elongation is reduced in twist mutant embryos, which lack mesoderm. We propose that cell shape change contributing to germ-band extension is a passive response to mechanical forces caused by the invaginating mesoderm.
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