Ground and excited states Gamow-Teller strength distributions of iron isotopes and associated capture rates for core-collapse simulations

This paper reports on the microscopic calculation of ground and excited states Gamow-Teller (GT) strength distributions, both in the electron capture and electron decay direction, for $^{54,55,56}$Fe. The associated electron and positron capture rates for these isotopes of iron are also calculated in stellar matter. These calculations were recently introduced and this paper is a follow-up which discusses in detail the GT strength distributions and stellar capture rates of key iron isotopes. The calculations are performed within the framework of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic \textit{state-by-state} calculation of GT strength functions and stellar capture rates which greatly increases the reliability of the results. For the first time experimental deformation of nuclei are taken into account. In the core of massive stars isotopes of iron, $^{54,55,56}$Fe, are considered to be key players in decreasing the electron-to-baryon ratio ($Y_{e}$) mainly via electron capture on these nuclide. The structure of the presupernova star is altered both by the changes in $Y_{e}$ and the entropy of the core material. Results are encouraging and are compared against measurements (where possible) and other calculations. The calculated electron capture rates are in overall good agreement with the shell model results. During the presupernova evolution of massive stars, from oxygen shell burning stages till around end of convective core silicon burning, the calculated electron capture rates on $^{54}$Fe are around three times bigger than the corresponding shell model rates. The calculated positron capture rates, however, are suppressed by two to five orders of magnitude.Comment: 18 pages, 12 figures, 10 table

rp-Process weak-interaction mediated rates of waiting-point nuclei

Electron capture and positron decay rates are calculated for neutron-deficient Kr and Sr waiting point nuclei in stellar matter. The calculation is performed within the framework of pn-QRPA model for rp-process conditions. Fine tuning of particle-particle, particle-hole interaction parameters and a proper choice of the deformation parameter resulted in an accurate reproduction of the measured half-lives. The same model parameters were used to calculate stellar rates. Inclusion of measured Gamow-Teller strength distributions finally led to a reliable calculation of weak rates that reproduced the measured half-lives well under limiting conditions. For the rp-process conditions, electron capture and positron decay rates on $^{72}$Kr and $^{76}$Sr are of comparable magnitude whereas electron capture rates on $^{78}$Sr and $^{74}$Kr are 1--2 orders of magnitude bigger than the corresponding positron decay rates. The pn-QRPA calculated electron capture rates on $^{74}$Kr are bigger than previously calculated. The present calculation strongly suggests that, under rp-process conditions, electron capture rates form an integral part of weak-interaction mediated rates and should not be neglected in nuclear reaction network calculations as done previously.Comment: 13 pages, 4 figures, 4 tables; Astrophysics and Space Science (2012

Effective link quality estimation as a means to improved end-to-end packet delivery in high traffic mobile ad hoc networks

Accurate link quality estimation is a fundamental building block in quality aware multi hop routing. In an inherently lossy, unreliable and dynamic medium such as wireless, the task of accurate estimation becomes very challenging. Over the years ETX has been widely used as a reliable link quality estimation metric. However, more recently it has been established that under heavy traffic loads ETX performance gets significantly worse. We examine the ETX metric's behavior in detail with respect to the MAC layer and UDP data; and identify the causes of its unreliability. Motivated by the observations made in our analysis, we present the design and implementation of our link quality measurement metric xDDR – a variation of ETX. This article extends xDDR to support network mobility. Our experiments show that xDDR substantially outperforms minimum hop count, ETX and HETX in terms of end-to-end packet delivery ratio in static as well as mobile scenarios.</p

On Discrimination Discovery and Removal in Ranked Data using Causal Graph

Predictive models learned from historical data are widely used to help companies and organizations make decisions. However, they may digitally unfairly treat unwanted groups, raising concerns about fairness and discrimination. In this paper, we study the fairness-aware ranking problem which aims to discover discrimination in ranked datasets and reconstruct the fair ranking. Existing methods in fairness-aware ranking are mainly based on statistical parity that cannot measure the true discriminatory effect since discrimination is causal. On the other hand, existing methods in causal-based anti-discrimination learning focus on classification problems and cannot be directly applied to handle the ranked data. To address these limitations, we propose to map the rank position to a continuous score variable that represents the qualification of the candidates. Then, we build a causal graph that consists of both the discrete profile attributes and the continuous score. The path-specific effect technique is extended to the mixed-variable causal graph to identify both direct and indirect discrimination. The relationship between the path-specific effects for the ranked data and those for the binary decision is theoretically analyzed. Finally, algorithms for discovering and removing discrimination from a ranked dataset are developed. Experiments using the real dataset show the effectiveness of our approaches.Comment: 9 page

Quantitative proteomics in resected renal cancer tissue for biomarker discovery and profiling

&lt;b&gt;Background:&lt;/b&gt;  Proteomics-based approaches for biomarker discovery are promising strategies used in cancer research. We present state-of-art label-free quantitative proteomics method to assess proteome of renal cell carcinoma (RCC) compared with noncancer renal tissues.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods:&lt;/b&gt;  Fresh frozen tissue samples from eight primary RCC lesions and autologous adjacent normal renal tissues were obtained from surgically resected tumour-bearing kidneys. Proteins were extracted by complete solubilisation of tissues using filter-aided sample preparation (FASP) method. Trypsin digested proteins were analysed using quantitative label-free proteomics approach followed by data interpretation and pathways analysis.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results:&lt;/b&gt;  A total of 1761 proteins were identified and quantified with high confidence (MASCOT ion score threshold of 35 and P-value &#60;0.05). Of these, 596 proteins were identified as differentially expressed between cancer and noncancer tissues. Two upregulated proteins in tumour samples (adipose differentiation-related protein and Coronin 1A) were further validated by immunohistochemistry. Pathway analysis using IPA, KOBAS 2.0, DAVID functional annotation and FLink tools showed enrichment of many cancer-related biological processes and pathways such as oxidative phosphorylation, glycolysis and amino acid synthetic pathways.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions:&lt;b&gt;  Our study identified a number of differentially expressed proteins and pathways using label-free proteomics approach in RCC compared with normal tissue samples. Two proteins validated in this study are the focus of on-going research in a large cohort of patients.&lt;p&gt;&lt;/p&gt

Molecular Cloning and Expression of Bacterial Mercuric Reductase Gene

In order to characterize the bacterial mercuric reductase (merA) gene, mercury resistant (Hgr) Escherichia coli strains have been isolated from various mercury contaminated sites of India. Their minimum inhibitory concentration (MIC) for Hg and zone of inhibition for different antibiotics were measured, and finally mer operon was localized by transforming isolated E. coli plasmid into mercury sensitive (Hgs) host E. coli DH5a cells. Oligonucleotide primers were designed by comparing the knownreported sequences of merA from Gram-negative bacterium (E. coli plasmid R100) and 1695 bp full length merA gene was amplified by PCR. A 1.695-kb DNA fragment of merA was inserted into isopropyl- -D-thiogalactopyranoside (IPTG) inducible bacterial expression vector pQE-30U/A. E. coli DH5 strains harboring the merA constructs showed higher mercury reductase enzyme (MerA) activity and expressed significantly more MerA than the control strains under aerobic conditions. The purified merA gene over expressed in the specific host E. coli BL21(DE3)Plys cells. Finally, expressed MerA protein was purifiedby Immobilized Metal-chelate Affinity Chromatography (IMAC) by using Ni- NTA column; and &#126;66.2 kDa bacterial MerA protein was detected after resolving on 10% sodium dodecyl sulphate poly acrylamide gel electrophoresis (SDS PAGE)

Venous thromboembolism (VTE) in post-prostatectomy patients

Radical prostatectomy (RP) is one of the recommended treatments to achieve oncological outcomes in localized prostate cancer. However, a radical prostatectomy is a major abdominopelvic surgery. Venous thromboembolism (VTE) is a well-known complication associated with surgical procedures, including RP. There is a lack of consensus regarding VTE prophylaxis in urological procedures. The aim of this systematic review and meta-analysis was to investigate different aspects of VTE in post-radical prostatectomy patients. A comprehensive literature search was performed, and relevant data were extracted. The primary aim was to perform a systematic review and meta-analysis (wherever possible) of VTE occurrence in post-RP patients in relation to surgical approach, pelvic lymph node dissection, and type of prophylaxis (mechanical or combined prophylaxis). The secondary aim was to investigate the incidence and other risk factors of VTE in post-RP patients. A total of 16 studies were included for quantitative analysis. Statistical methods for analysis included the DerSimonian–Laird random effects. We were able to conclude that the overall incidence of VTE in post-radical prostatectomy is 1% (95% CI) and minimally invasive procedures (MIS), including laparoscopic, as well as robotic procedures for radical prostatectomy and RP without pelvic lymph node dissection (PLND), are associated with less risk of developing VTE. Additional pharmacological prophylaxis to mechanical methods may not be necessary in all cases and should be considered in high-risk patients only