Reliable Broadcast over Cognitive Radio Networks: A Bipartite Graph-Based Algorithm

Cognitive radio (CR) is a promising technology that aims to enhance the spectrum utilisation by enabling unlicenced users to opportunistically use the vacant spectrum bands assigned to licenced users. Broadcasting is considered as a fundamental operation in wireless networks, as well as in cognitive radio networks (CRNs). The operation of most network protocols in the ad hoc network depends on broadcasting control information from neighbouring nodes. In traditional single-channel or multichannel ad hoc networks, due to uniform channel availability, broadcasting is easily implemented as nodes are tuned to a single common channel. On the contrary, broadcasting in CR ad hoc networks is both a challenging and complex task. The complexity emerges from the fact that different CR users might acquire different channels at different times. Consequently, this partitions the network into different clusters. In this chapter, the problem of broadcasting in ad hoc CR networks is presented, current solutions for the problem are discussed and an intelligent solution for broadcasting based on graph theory to connect different local topologies is developed

Identification of 2-Aminothiazole-4-Carboxylate Derivatives Active against Mycobacterium tuberculosis H37Rv and the β-Ketoacyl-ACP Synthase mtFabH

Background Tuberculosis (TB) is a disease which kills two million people every year and infects approximately over one-third of the world's population. The difficulty in managing tuberculosis is the prolonged treatment duration, the emergence of drug resistance and co-infection with HIV/AIDS. Tuberculosis control requires new drugs that act at novel drug targets to help combat resistant forms of Mycobacterium tuberculosis and reduce treatment duration. Methodology/Principal Findings Our approach was to modify the naturally occurring and synthetically challenging antibiotic thiolactomycin (TLM) to the more tractable 2-aminothiazole-4-carboxylate scaffold to generate compounds that mimic TLM's novel mode of action. We report here the identification of a series of compounds possessing excellent activity against M. tuberculosis H37Rv and, dissociatively, against the β-ketoacyl synthase enzyme mtFabH which is targeted by TLM. Specifically, methyl 2-amino-5-benzylthiazole-4-carboxylate was found to inhibit M. tuberculosis H37Rv with an MIC of 0.06 µg/ml (240 nM), but showed no activity against mtFabH, whereas methyl 2-(2-bromoacetamido)-5-(3-chlorophenyl)t​hiazole-4-carboxylateinhibited mtFabH with an IC50 of 0.95±0.05 µg/ml (2.43±0.13 µM) but was not active against the whole cell organism. Conclusions/Significance These findings clearly identify the 2-aminothiazole-4-carboxylate scaffold as a promising new template towards the discovery of a new class of anti-tubercular agents

Performance of Coded Multi-Line Copper Wire for G.fast Communications in the Presence of Impulsive Noise

In this paper, we focus on the design of a multi-line copper wire (MLCW) communication system. First, we construct our proposed MLCW channel and verify its characteristics based on the Kolmogorov-Smirnov test. In addition, we apply Middleton class A impulsive noise (IN) to the copper channel for further investigation. Second, the MIMO G.fast system is adopted utilizing the proposed MLCW channel model and is compared to a single line G-fast system. Second, the performance of the coded system is obtained utilizing concatenated interleaved Reed-Solomon (RS) code with four-dimensional trellis-coded modulation (4D TCM), and compared to the single line G-fast system. Simulations are obtained for high quadrature amplitude modulation (QAM) constellations that are commonly used with G-fast communications, the results demonstrate that the bit error rate (BER) performance of the coded MLCW system shows an improvement compared to the single line G-fast systems

Enhancing Water Removal from Whole Stillage by Enzyme Addition during Fermentation

The Removal of Water from Coproducts in the Fuel Ethanol Process Requires a Significant Energy Input. in This Study, the Addition of Commercially Available Cell-Wall-Degrading Enzymes Was Investigated to Determine Whether or Not the Enzymes Could Reduce the Amount of Water Bound within the Wet Grains. This Would Have the Effect of Allowing More Water to Be Removed during Centrifugation, Reducing the Time and Energy Needed during the Drying Process. the Experiment Screened 15 Cell-Wall-Degrading Enzyme Preparations. a Significant Reduction in Water-Binding Capacity Was Found for a Number of Enzymes Tested in the Initial Screening. the Experiment Was Repeated and Two Enzymes Were Identified to Have the Highest Whole Stillage Dewatering Effect, 15 and 14% More Water Removed for Enzyme Preparations a and G, respectively. Adding Different Enzyme Preparation Amounts to the Mash Showed Varying Effects, with the Potential to Allow for an Optimization of Enzymes Cost and Energy Savings. in Some Cases, an Enzyme Dosage of 0.5 ML Worked as Well, If Not Better, Than a Dosage of 1 ML. These Results Can Translate into Improvements in the overall Energy Efficiency of the Process Because the Wet Grains Entering the Drier Would Contain Less Moisture Than in the Conventional Process Thus Requiring a Shorter Residence Time in the Drier

Silicon grain boundary passivation for photovoltaics: a novel approach with small polar molecules

Grain boundaries (GBs) play a major role in determining the device performance of in particular polycrystalline thin film solar cells including Si, CdTe and CIGS. Hydrogen passivation has been traditionally applied to passivate the defects at GBs. However, hydrogenated films such as amorphous silicon (a-Si:H) and microcrystalline silicon (c-Si:H) are subject to light-induced degradation effects. In this study on multicrystalline (mc)-Si wafers, we found an excellent correlation between the grain misorientation and the corresponding electrical resistivity across grain boundaries. In particular, the charge transport across GBs was greatly enhanced after the wafers were properly treated in our polar molecule solutions. The results were explained to be due to the more effective charge neutralization and passivation of polar molecules on localized charges at GBs. These findings may help us achieve high-quality materials at low cost for high-efficiency solar cells by improving the carrier transport and minimizing the carrier recombination. We also believe that this study will help us with a deeper understanding on GBs and their behaviors for the applications not only in photovoltaics, but also in other solid-state devices such as thin-film transistors. © 2012 IEEE.published_or_final_versionThe 38th IEEE Photovoltaic Specialists Conference (PVSC), Austin Cenvention Centre, Austin, Texas, USA, 3-8 June 2012. In Conference Record, 2012, p. 001144 - 00114

Large-scale latitudinal and vertical distributions of NMHCs and selected halocarbons in the troposphere over the Pacific Ocean during the March-April 1999 Pacific Exploratory Mission (PEM-Tropics B)

Nonmethane hydrocarbons (NMHCs) and selected halocarbons were measured in whole air samples collected over the remote Pacific Ocean during NASA's Global Tropospheric Experiment (GTE) Pacific Exploratory Mission-Tropics B (PEM-Tropics B) in March and early April 1999. The large-scale spatial distributions of NMHCs and C2Cl4 reveal a much more pronounced north-south interhemispheric gradient, with higher concentrations in the north and lower levels in the south, than for the late August to early October 1996 PEM-Tropics A experiment. Strong continental outflow and winter-long accumulation of pollutants led to seasonally high Northern Hemisphere trace gas levels during PEM-Tropics B. Observations of enhanced levels of Halon 1211 (from developing Asian nations such as the PRC) and CH3Cl (from SE Asian biomass burning) support a significant southern Asian influence at altitudes above 1 km and north of 10° N. By contrast, at low altitude over the North Pacific the dominance of urban/industrial tracers, combined with low levels of Halon 1211 and CH3Cl, indicate a greater influence from developed nations such as Japan, Europe, and North America. Penetration of air exhibiting aged northern hemisphere characteristics was frequently observed at low altitudes over the equatorial central and western Pacific south to ∼5° S. The relative lack of southern hemisphere biomass burning sources and the westerly position of the South Pacific convergence zone contributed to significantly lower PEM-Tropics B mixing ratios of the NMHCs and CH3Cl south of 10° S compared to PEM-Tropics A. Therefore the trace gas composition of the South Pacific troposphere was considerably more representative of minimally polluted tropospheric conditions during PEM-Tropics B. Copyright 2001 by the American Geophysical Union