4,136 research outputs found
Active Queue Management for Fair Resource Allocation in Wireless Networks
This paper investigates the interaction between end-to-end flow control and MAC-layer scheduling on wireless links. We consider a wireless network with multiple users receiving information from a common access point; each user suffers fading, and a scheduler allocates the channel based on channel quality,but subject to fairness and latency considerations. We show that the fairness property of the scheduler is compromised by the transport layer flow control of TCP New Reno. We provide a receiver-side control algorithm, CLAMP, that remedies this situation. CLAMP works at a receiver to control a TCP sender by setting the TCP receiver's advertised window limit, and this allows the scheduler to allocate bandwidth fairly between the users
Deep K_s-near-infrared Surface Photometry of 80 Dwarf Irregular Galaxies in the Local Volume
We present deep near-infrared (K_s) images and surface photometry for 80 dwarf irregular galaxies (dIs) within ~5 Mpc of the Milky Way. The galaxy images were obtained at five different facilities between 2004 and 2006. The image reductions and surface photometry have been performed using methods specifically designed for isolating faint galaxies from the high and varying near-infrared sky level. Fifty-four of the 80 dIs have surface brightness profiles which could be fit to a hyperbolic-secant (sech) function, while the remaining profiles could be fit to the sum of a sech and a Gaussian function. From these fits, we have measured central surface brightnesses, scale lengths, and integrated magnitudes. This survey is part of a larger study of the connection between large-scale structure and the global properties of dIs, the hypothesized building-blocks of more massive galaxies
EFFECT OF SEGMENTAL VIBRATION ON HAND AND PINCH GRIP STRENGTHS IN HEALTHY SUBJECTS
Handgrip and pinch strengths are important markers in many sports as well as in determining health status. Many interventions have been proposed for increasing hand muscle strength. The aim of this study was to investigate the effect of segmental hand vibration on hand and pinch grip strengths. Ninety-two healthy university students were randomly assigned into two equal groups. By the end of the study, Group (A) and (B) consisted of 40 and 37 participants, respectively. The measurements consisted of the hand grip and pinch grip strengths using electronic dynamometer, measured in Kg, before, after three weeks, and after six weeks of training. Group (A) underwent isometric exercise training using hand gripper as follows: 4 seconds maximum grip, release for 2 seconds, repeated for 1 minute for three sets and with 3 minutes rest in between. Group (B) had the same exercise implemented in group (A) with the addition of five minutes of segmental vibration on both upper limb with 30Hz and amplitude of 2mm. The training was done two times per week for six weeks. Results revealed that both groups did demonstrate significant increase in hand and grip strengths after six weeks (p.05). It can be concluded that, segmental upper limb vibration does not have additional effect over isometric muscle training alone on hand grip and pinch grip strengths
Family history of prostate and colorectal cancer and risk of colorectal cancer in the Women's health initiative.
BackgroundEvidence suggests that risk of colorectal and prostate cancer is increased among those with a family history of the same disease, particularly among first-degree relatives. However, the aggregation of colorectal and prostate cancer within families has not been well investigated.MethodsAnalyses were conducted among participants of the Women's Health Initiative (WHI) observational cohort, free of cancer at the baseline examination. Subjects were followed for colorectal cancer through August 31st, 2009. A Cox-proportional hazards regression modeling approach was used to estimate risk of colorectal cancer associated with a family history of prostate cancer, colorectal cancer and both cancers among first-degree relatives of all participants and stratified by race (African American vs. White).ResultsOf 75,999 eligible participants, there were 1122 colorectal cancer cases diagnosed over the study period. A family history of prostate cancer alone was not associated with an increase in colorectal cancer risk after adjustment for confounders (aHR =0.94; 95% CI =0.76, 1.15). Separate analysis examining the joint impact, a family history of both colorectal and prostate cancer was associated with an almost 50% increase in colorectal cancer risk (aHR = 1.48; 95% CI = 1.04, 2.10), but similar to those with a family history of colorectal cancer only (95% CI = 1.31; 95% CI = 1.11, 1.54).ConclusionsOur findings suggest risk of colorectal cancer is increased similarly among women with colorectal cancer only and among those with both colorectal and prostate cancer diagnosed among first-degree family members. Future studies are needed to determine the relative contribution of genes and shared environment to the risk of both cancers
A case report of a huge congenital granular cell epulis operated under local anesthesia
Congenital granular cell epulis (CGCE) is a very rare benign soft tissue lesion of the neonate, it most frequently located on the anterior maxillary alveolar ridge. It has a female predilection. It is a tumor with no tendency to recur after excision. The exact histogenesis of this tumor remains unresolved and it may be hamartomata.Key words: Congenital granular cell tumor, gingival tumor, newborn, local anesthesi
Does Corporate Lobbying Benefit Society?
Lobbying, defined as an effort to influence policy through strategic communication, has grown dramatically in recent years. This paper presents three viewpoints regarding the societal impact of corporate lobbying on society: one perspective argues that lobbying will be primarily beneficial, an alternative perspective contests this viewpoint and suggests that it is generally harmful, and the third argues that the impact is contingent on a number of factors. Proponents of lobbying argue that it is a vital mechanism to transmit valuable information and expertise to policymakers, leading to substantive legislative solutions for resolving complex societal issues. Critics, on the other hand, point out that business dominates lobbying and can leverage vast resources to push biased information in the pursuit of narrow profit-oriented interests. There are three key axes of contention between these three perspectives; first, concerning the definition of lobbying and its relation to corporate power; second, its relationship to democratic processes; and third, regarding alignment or conflict between societal and business interests. The paper examines these issues and draws implications for future research
CHARACTERIZATION OF LABELED PROGENITOR DERIVED ENDOTHELIAL CELLS FOR TISSUE ENGINEERING APPLICATIONS
Oral Communication presented at the ";Forum des Jeunes Chercheurs";, Brest (France) 2011
Phosphorylation regulates human T-cell leukemia virus type 1 Rex function
Background: Human T-cell leukemia virus type 1 (HTLV-1) is a pathogenic complex
deltaretrovirus, which is the causative agent of adult T-cell leukemia/lymphoma (ATL) and HTLV-
1-associated myelopathy/tropical spastic paraparesis. In addition to the structural and enzymatic
viral gene products, HTLV-1 encodes the positive regulatory proteins Tax and Rex along with viral
accessory proteins. Tax and Rex proteins orchestrate the timely expression of viral genes
important in viral replication and cellular transformation. Rex is a nucleolar-localizing shuttling
protein that acts post-transcriptionally by binding and facilitating the export of the unspliced and
incompletely spliced viral mRNAs from the nucleus to the cytoplasm. HTLV-1 Rex (Rex-1) is a
phosphoprotein and general protein kinase inhibition correlates with reduced function. Therefore,
it has been proposed that Rex-1 function may be regulated through site-specific phosphorylation.
Results: We conducted a phosphoryl mapping of Rex-1 over-expressed in transfected 293 T cells
using a combination of affinity purification and liquid chromatography tandem mass spectrometry.
We achieved 100% physical coverage of the Rex-1 polypeptide and identified five novel
phosphorylation sites at Thr-22, Ser-36, Thr-37, Ser-97, and Ser-106. We also confirmed evidence
of two previously identified residues, Ser-70 and Thr-174, but found no evidence of
phosphorylation at Ser-177. The functional significance of these phosphorylation events was
evaluated using a Rex reporter assay and site-directed mutational analysis. Our results indicate that
phosphorylation at Ser-97 and Thr-174 is critical for Rex-1 function.
Conclusion: We have mapped completely the site-specific phosphorylation of Rex-1 identifying a
total of seven residues; Thr-22, Ser-36, Thr-37, Ser-70, Ser-97, Ser-106, and Thr-174. Overall, this
work is the first to completely map the phosphorylation sites in Rex-1 and provides important
insight into the regulation of Rex-1 function
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