424 research outputs found

    Biosand Filter for Removal of Chemical Contaminants From Water

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    Numerous reports by the United Nations and the World Health Organization have indicated a significant worldwide problem with water pollution and inaccessibility to potable drinking water. Due to technological and economical barriers, the problem with water pollution is particularly more serious for under-developed and developing countries. The present study is aimed at designing, constructing and evaluating a cost-effective biosand filter was undertaken. Results indicated the removal of up to 80% total hardness, 86% chlorides, 96% turbidity and 90% colour. Moreover, the filter's performance was appraised by the absence of E. coli in the filtered sample. The filter describes the proven bioremediation technology and its ability to empower at-risk populations to use naturally occurring biology and readily available materials as a sustainable way to achieve the health benefits of safe drinking water

    Actuator Constrained Trajectory Generation and Control for Variable-Pitch Quadrotors

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    Control and trajectory generation algorithms for a quadrotor helicopter with variable-pitch propellers are presented. The control law is not based on near-hover assumptions, allowing for large attitude deviations from hover. The trajectory generation algorithm ts a time-parametrized polynomial through any number of way points in R3, with a closed-form solution if the corresponding way point arrival times are known a priori. When time is not specifi ed, an algorithm for fi nding minimum-time paths subject to hardware actuator saturation limitations is presented. Attitude-specifi c constraints are easily embedded in the polynomial path formulation, allowing for aerobatic maneuvers to be performed using a single controller and trajectory generation algorithm. Experimental results on a variable pitch quadrotor demonstrate the control design and example trajectories.National Science Foundation (U.S.) (Graduate Research Fellowship under Grant No. 0645960

    Assignment of the <i>TYK2</i> gene to equine chromosome 7q12-q13 (Brief report)

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    Abstract. Tyrosine kinase 2 (TYK2) is a member of the janus kinase gene family and encodes an 1187 amino acid protein. All four members of the janus kinase family JAK1, JAK2, JAK3, and TYK2 associate with various cytokine receptors and mediate the signal transduction by tyrosine phosphorylation of downstream targets (YAMOAKA et al., 2004). Studies with tyk2 deficient mice demonstrated impairment of interferon α/β signaling (KARAGHIOSOFF et al., 2003). Mutations in the murine tyk2 gene are associated with increased susceptibility to infectious and autoimmune diseases (SHAW et al., 2003). The human TYK2 gene consists of 25 exons spanning 30,003 bp on human chromosome 19p13.2 starting at 10,322,209 bp. The objective of this study was to determine the chromosomal location of TYK2 in the horse by FISH and RH mapping. </jats:p

    The Potential Energy Landscape and Mechanisms of Diffusion in Liquids

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    The mechanism of diffusion in supercooled liquids is investigated from the potential energy landscape point of view, with emphasis on the crossover from high- to low-T dynamics. Molecular dynamics simulations with a time dependent mapping to the associated local mininum or inherent structure (IS) are performed on unit-density Lennard-Jones (LJ). New dynamical quantities introduced include r2_{is}(t), the mean-square displacement (MSD) within a basin of attraction of an IS, R2(t), the MSD of the IS itself, and g_{loc}(t) the mean waiting time in a cooperative region. At intermediate T, r2_{is}(t) posesses an interval of linear t-dependence allowing calculation of an intrabasin diffusion constant D_{is}. Near T_{c} diffusion is intrabasin dominated with D = D_{is}. Below T_{c} the local waiting time tau_{loc} exceeds the time, tau_{pl}, needed for the system to explore the basin, indicating the action of barriers. The distinction between motion among the IS below T_{c} and saddle, or border dynamics above T_{c} is discussed.Comment: submitted to pr

    Increased yield of smear positive pulmonary TB cases by screening patients with >2 weeks cough, compared to >3 weeks and adequacy of 2 sputum smear examinations for diagnosis

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    Background RNTCP recommends examining three sputum smears for AFB from Chest Symptomatics (CSs) with cough of >3 weeks for diagnosis of Pulmonary TB (PTB). A previous multi-centric study from Tuberculosis Research centre (TRC) has shown that the yield of sputum positive cases can be increased if duration of cough for screening was reduced to >2 weeks. Other studies have shown that two smear examinations are adequate for diagnosis of smear positive PTB . To validate the above findings, a cross sectional multi-centric study was repeated in different settings in five geographical areas in India. Methods Three primary and secondary level health facilities with high out-patient attendance were selected from two Tuberculosis Units (TU) in each of the 15 selected districts to screen about 10,000 new adult outpatients from each state. For patients who did not volunteer history of cough, symptoms were elicited using a structured simple questionnaire. All the CSs were referred for sputum examination. Results A total of 96,787 out-patients were registered. Among them 69,209 (72%) were new adult out-patients. Using >2 weeks of cough instead of > 3 weeks as the criterion for screening, there was an overall increase of 58% in CS and 23% increase in the detection of smear-positive cases. Among 211 patients, 210 were positive at least by one smear from the initial two specimens. Increase in the work-load if 2 smears were done for patients with cough of >2 weeks cough were 2 specimens (i.e.13 to 15) per day for an adult OPD of 150. Conclusion The yield of sputum positive PTB cases can be improved by screening patients with >2 weeks cough and two specimens are adequate for diagnosis

    Gajah. Securing the Future for Elephants in India.

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    It is estimated that six in every ten wild Asian elephants live in India. This report by the Ministry of Environment and Forests in India outlines plans to safeguard the species and associated habitats in the face of rapid economic expansion and development pressures

    Potential energy landscape-based extended van der Waals equation

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    The inherent structures ({\it IS}) are the local minima of the potential energy surface or landscape, U(r)U({\bf r}), of an {\it N} atom system. Stillinger has given an exact {\it IS} formulation of thermodynamics. Here the implications for the equation of state are investigated. It is shown that the van der Waals ({\it vdW}) equation, with density-dependent aa and bb coefficients, holds on the high-temperature plateau of the averaged {\it IS} energy. However, an additional ``landscape'' contribution to the pressure is found at lower TT. The resulting extended {\it vdW} equation, unlike the original, is capable of yielding a water-like density anomaly, flat isotherms in the coexistence region {\it vs} {\it vdW} loops, and several other desirable features. The plateau energy, the width of the distribution of {\it IS}, and the ``top of the landscape'' temperature are simulated over a broad reduced density range, 2.0ρ0.202.0 \ge \rho \ge 0.20, in the Lennard-Jones fluid. Fits to the data yield an explicit equation of state, which is argued to be useful at high density; it nevertheless reproduces the known values of aa and bb at the critical point

    Biosand Filter for Removal of Chemical Contaminants from Water

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    Numerous reports by the United Nations and the World Health Organization have indicated a significant worldwide problem with water pollution and inaccessibility to potable drinking water. Due to technological and economical barriers, the problem with water pollution is particularly more serious for under-developed and developing countries. The present study is aimed at designing, constructing and evaluating a cost-effective biosand filter was undertaken. Results indicated the removal of up to 80% total hardness, 86% chlorides, 96% turbidity and 90% colour. Moreover, the filter’s performance was appraised by the absence of E. coli in the filtered sample. The filter describes the proven bioremediation technology and its ability to empower at-risk populations to use naturally occurring biology and readily available materials as a sustainable way to achieve the health benefits of safe drinking water

    Genome-wide analysis of regions similar to promoters of histone genes

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    Background: The purpose of this study is to: i) develop a computational model of promoters of human histone-encoding genes (shortly histone genes), an important class of genes that participate in various critical cellular processes, ii) use the model so developed to identify regions across the human genome that have similar structure as promoters of histone genes; such regions could represent potential genomic regulatory regions, e.g. promoters, of genes that may be coregulated with histone genes, and iii/ identify in this way genes that have high likelihood of being coregulated with the histone genes. Results: We successfully developed a histone promoter model using a comprehensive collection of histone genes. Based on leave-one-out cross-validation test, the model produced good prediction accuracy (94.1% sensitivity, 92.6% specificity, and 92.8% positive predictive value). We used this model to predict across the genome a number of genes that shared similar promoter structures with the histone gene promoters. We thus hypothesize that these predicted genes could be coregulated with histone genes. This hypothesis matches well with the available gene expression, gene ontology, and pathways data. Jointly with promoters of the above-mentioned genes, we found a large number of intergenic regions with similar structure as histone promoters. Conclusions: This study represents one of the most comprehensive computational analyses conducted thus far on a genome-wide scale of promoters of human histone genes. Our analysis suggests a number of other human genes that share a high similarity of promoter structure with the histone genes and thus are highly likely to be coregulated, and consequently coexpressed, with the histone genes. We also found that there are a large number of intergenic regions across the genome with their structures similar to promoters of histone genes. These regions may be promoters of yet unidentified genes, or may represent remote control regions that participate in regulation of histone and histone-coregulated gene transcription initiation. While these hypotheses still remain to be verified, we believe that these form a useful resource for researchers to further explore regulation of human histone genes and human genome. It is worthwhile to note that the regulatory regions of the human genome remain largely un-annotated even today and this study is an attempt to supplement our understanding of histone regulatory regions.Statistic

    A critical assessment of methods for the intrinsic analysis of liquid interfaces. 1. surface site distributions

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    Substantial progress in our understanding of interfacial structure and dynamics has stemmed from the recent development of algorithms that allow for an intrinsic analysis of fluid interfaces. These work by identifying the instantaneous location of the interface, at the atomic level, for each molecular configuration and then computing properties relative to this location. Such a procedure eliminates the broadening of the interface caused by capillary waves and reveals the underlying features of the system. However, a precise definition of which molecules actually belong to the interfacial layer is difficult to achieve in practice. Furthermore, it is not known if the different intrinsic analysis methods are consistent with each other and yield similar results for the interfacial properties. In this paper, we carry out a systematic and detailed comparison of the available methods for intrinsic analysis of fluid interfaces, based on a molecular dynamics simulation of the interface between liquid water and carbon tetrachloride. We critically assess the advantages and shortcomings of each method, based on reliability, robustness, and speed of computation, and establish consistent criteria for determining which molecules belong to the surface layer. We believe this will significantly contribute to make intrinsic analysis methods widely and routinely applicable to interfacial systems
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