Heavy metal speciation and their accumulation in sediments of Lake Burullus, Egypt

Several sediment samples in Lake Burullus have been affected by the discharges of heavy metals through different drains. The study aimed to analyze the chemical speciation of these metals. In particular, the chemical forms of Cd, Cu, Fe, Mn, Pb and Zn in sediments collected in spring season were studied using a sequential chemical extraction method. In general, all the elements recorded highest concentrations in the area near the discharge point. The data indicated that, the sediments were under a wide variety of environmental conditions ranging from oxic to fully anoxic conditions. Owing a wide variety of grain sizes and organic matter, these metals showed the order of abundance: Fe > Mn > Zn > Cu > Cd > Pb. Significant correlations between iron with clay, organic carbon and manganese concentrations were calculated as (r=0.685, 0.581 and 0.610, P= 0.05), respectively. This gives an idea about association of iron and manganese as main compositions of clays. In the mean time, it showed insignificant relation with total carbonate and all phosphorus forms. The metal speciation characterizes the degree to which they are potentially labile or bioavailability. It gives different fraction ratios depending on binding and sediment origin.Key words: Heavy metals, chemical speciation, sediments, Burullus, Lake

The Influence of Inclined Barriers on Airflow Over a High Speed Train under Crosswind Condition

During the last decade the problem of crosswind has developed into an important subject amongst the topics in railway engineering. When high speed trains are exposed to extreme weather conditions such as intense lateral winds, storms and tornadoes, lateral loads acting on the train can cause overturning of the train. This present work analyzed the aerodynamic mechanism of a high-speed train with and without two inclined barriers. A three-dimensional numerical model of a train-barrier-crosswind system is adopted to investigate the effects of inclined angles of barriers on the flow patterns and the aerodynamic coefficients. This perusal surveys the design criteria indispensable for barriers that are installed alongside the tracks to protect the passing trains under strong side winds. By using a numerical code based on Lattice Boltzmann Method (LBM) it is attempted to initially investigate the behavior of airflow behind the barriers. Finally, it is found that the presence of the barriers has a great impact on decreasing the intensity of the air flow above the train. This study’s findings could be utilized as a reference for practical usage of barriers in railway transportation

Glot500: Scaling Multilingual Corpora and Language Models to 500 Languages

The NLP community has mainly focused on scaling Large Language Models (LLMs) vertically, i.e., making them better for about 100 languages. We instead scale LLMs horizontally: we create, through continued pretraining, Glot500-m, an LLM that covers 511 predominantly low-resource languages. An important part of this effort is to collect and clean Glot500-c, a corpus that covers these 511 languages and allows us to train Glot500-m. We evaluate Glot500-m on five diverse tasks across these languages. We observe large improvements for both high-resource and low-resource languages compared to an XLM-R baseline. Our analysis shows that no single factor explains the quality of multilingual LLM representations. Rather, a combination of factors determines quality including corpus size, script, “help” from related languages and the total capacity of the model. Our work addresses an important goal of NLP research: we should notlimit NLP to a small fraction of the world’s languages and instead strive to support as many languages as possible to bring the benefits of NLP technology to all languages and cultures. Code, data and models are available at https://github.com/cisnlp/Glot500

Comparison of SPECT bone scintigraphy with MRI for diagnosis of meniscal tears

BACKGROUND: Scintigraphy has been considered as competitive to MRI, but limited data are available on the accuracy of single photon emission tomography (SPECT) compared with MRI for the assessment of meniscal tears. Our objective was to assess the value of SPECT in comparison to MRI. METHODS: Between January 2003 and March 2004, sixteen patients were studied with both modalities and the accuracy rates of SPECT scan results, and MRI findings in the diagnosis of meniscal tears were compared. Arthroscopy was the gold standard. RESULTS: The respective sensitivity rate, specificity rate, and positive and negative predictive accuracies of MRI were 89%, 94%, 93%, and 79% and for SPECT those were 78%, 94%, 94%, and 88%. There was good agreement on the presence or absence of tears between two modalities (κ statistic = 0.699). CONCLUSION: SPECT and MRI are both valuable imaging techniques. SPECT is a useful alternative when MRI is unavailable or unsuitable and it is beneficial when more possible accuracy is desired (such as when MRI results are either inconclusive or conflict with other clinical data)

Hepatitis C virus genotype frequency in Isfahan province of Iran: a descriptive cross-sectional study

<p>Abstract</p> <p>Background</p> <p>Hepatitis C is an infectious disease affecting the liver, caused by the hepatitis C virus (HCV). The hepatitis C virus is a small, enveloped, single-stranded, positive sense RNA virus with a large genetic heterogeneity. Isolates have been classified into at least eleven major genotypes, based on a nucleotide sequence divergence of 30-35%. Genotypes 1, 2 and 3 circulate around the world, while other genotypes are mainly restricted to determined geographical areas. Genotype determination of HCV is clinically valuable as it provides important information which can be used to determine the type and duration of therapy and to predict the outcome of the disease.</p> <p>Results</p> <p>Plasma samples were collected from ninety seven HCV RNA positive patients admitted to two large medical laboratory centers in Isfahan province (Iran) from the years 2007 to 2009. Samples from patients were subjected to HCV genotype determination using a PCR based genotyping kit. The frequency of HCV genotypes was determined as follows: genotype 3a (61.2%), genotype 1a (29.5%), genotype 1b (5.1%), genotype 2 (2%) and mixed genotypes of 1a+3a (2%).</p> <p>Conclusion</p> <p>Genotype 3a is the most frequent followed by the genotype 1a, genotype 1b and genotype 2 in Isfahan province, Iran.</p

Quantum-classical access networks with embedded optical wireless links

We examine the applicability of wireless indoor quantum key distribution (QKD) in hybrid quantum-classical networks. We propose practical configurations that would enable wireless access to such networks. The proposed setups would allow an indoor wireless user, equipped with a QKD-enabled mobile device, to communicate securely with a remote party on the other end of the access network. QKD signals, sent through wireless indoor channels, are combined with classical ones and sent over shared fiber links to the remote user. Dense wavelength-division multiplexing would enable the simultaneous transmission of quantum and classical signals over the same fiber. We consider the adverse effects of the background noise induced by Raman-scattered light on the QKD receivers due to such an integration. In addition, we consider the loss and the background noise that arise from indoor environments. We consider a number of discrete and continuous-variable QKD protocols and study their performance in different scenarios