779 research outputs found

    Water Quality Assessment of the Southwestern and Coastal River Systems of Ghana

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    Investigation into physico-chemical water quality and dissolved heavy metal contents of major rivers from the Southwestern and Coastal River Systems of Ghana from 19 stations was undertaken from 2007 to 2010. The waters are used in their raw states for domestic purposes including drinking in most communities in the study area. The concentrations of the various parameters were assessed in relation to the Ghana Raw Water Quality Criteria and Guidelines for raw water, and in few instances, are compared with the WHO guidelines where the waters are known to be sources of drinking water. Turbidity, Total Suspended Solids (TSS) and Total Hardness were the physical parameters selected for the quality assessment of the waters in relation to domestic use. An Adapted Water Quality Index (WQI) was used to characterize the overall water quality status of the waters.  Turbidity and TSS were found to be above their respective Target Water Quality Range (TWQR) values for raw water, while Total Hardness concentration were within guideline values. The levels of the trace metals investigated in the waters, Fe, Mn, Zn, Pb, Cr, Ni, Cu, As, Cd, and Hg, were found to be  generally low, and do not yet pose health risks in the dissolved form. However, Fe and Mn levels were moderately high, exceeding their respective TWQR values stipulated for Ghanaian freshwaters.  An assessment of non-cancerous health risk from exposure to Fe, Mn, and Zn was performed with the Risk Integrated Software for cleanup (RISC 4.02) developed by the USEPA. Results of the risk assessment, however, revealed a hazard quotient greater than 1 in some locations, indicating that the risk of adverse health effects associated with exposure to zinc, manganese and iron is high in those locations. Efforts should therefore be made to prevent metal pollutants, mainly from mining activities, from entering our water bodies to keep them suitable for their intended uses. Keywords: Risk assessment, Southwestern Rivers Systems, Coastal Rivers Systems, Water Quality, Water Quality Index

    Underlying indicators for measuring smartness of buildings in the construction industry

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    Purpose: This study investigates the underlying indicators for measuring the smartness of buildings in the construction industry; where the Smart Building Technology (SBT) concept (which incorporates elements of the Zero Energy Building (NZEB) concept) could ensure efficient energy consumption and high performance of buildings. Design/methodology/approach: An overarching post-positivist and empirical epistemological design was adopted to analyze primary quantitative data collected via a structured questionnaire survey with 227 respondents. The mean ranking analysis and one-sample t-test were employed to analyse data. Findings: Research findings revealed that the level of knowledge of smart building indicators is averagely high in the Ghanaian construction industry. Future research is required to evaluate the awareness level of Smart Building Technologies (SBTs) by construction professionals and identify barriers to its adoption. Originality/value: A blueprint guidance model (consisting of significant indicators for measuring building smartness) was developed to help improve building performance and inform policymakers

    Mycobacterial species causing pulmonary tuberculosis At the korle bu teaching hospital, Accra,

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    Objective: Characterize mycobacterial species causing pulmonary tuberculosis (PTB) at the Korle-Bu Teaching Hospital in Ghana.Design: Sputum smear positive samples, two (2) from 70 patients diagnosed as having tuberculosis, after they had consented, were collected from the Korle-Bu Teaching Hospital Chest Clinic betweenJanuary and July 2003. Setting: Korle-Bu Teaching Hospital Chest Clinic, Accra. Results: Sixty-four mycobacterial isolates wereobtained and confirmed as members of Mycobacterium tuberculosis complex by colonial morphology and conventional biochemical assays. Fortyseven (73%) were M. tuberculosis, the human strain, 2 (3%) M. bovis, the bovine strain, 13 (20%) M. africanum I (West Africa type), and 2 (3%) M. africanum II (East Africa type). Conclusion: The results indicate that, there are various strains causing PTB at the Korle-BuTeaching Hospital and of great concern is M. bovis, which mostly causes extra-PTB in humans but found to cause PTB in this study. This calls for the need to conduct a nationwide survey using bothconventional and molecular techniques to characterize various mycobacterial species causing TB in Ghana. This will result in better understanding of the various strains circulating in the country andinform individual TB treatment regimen especially the inclusion or exclusion of pyrazinamide

    Thermodynamic and diamagnetic properties of weakly doped antiferromagnets

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    Finite-temperature properties of weakly doped antiferromagnets as modeled by the two-dimensional t-J model and relevant to underdoped cuprates are investigated by numerical studies of small model systems at low doping. Two numerical methods are used: the worldline quantum Monte Carlo method with a loop cluster algorithm and the finite-temperature Lanczos method, yielding consistent results. Thermodynamic quantities: specific heat, entropy and spin susceptibility reveal a sizeable perturbation induced by holes introduced into a magnetic insulator, as well as a pronounced temperature dependence. The diamagnetic susceptibility introduced by coupling of the magnetic field to the orbital current reveals an anomalous temperature dependence, changing character from diamagnetic to paramagnetic at intermediate temperatures.Comment: LaTeX, 10 pages, 10 figures, submitted to Phys. Rev.

    Wind Energy Assessment Study for Nevada -- Tall Tower Deployment (Stone Cabin)

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    The objective of this work effort was to characterize wind shear and turbulence for representative wind-developable areas in Nevada

    DRI-wind energy assessment and forecasting

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    The second annual Nevada Renewable Energy Consortium meeting took place at UNLV on August 20. The meeting focused on the current three NVREC program areas: Solar, Biomass and Geothermal. Presentations were made by participating entities and a poster session followed

    LSST: from Science Drivers to Reference Design and Anticipated Data Products

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    (Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg2^2 field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5σ\sigma point-source depth in a single visit in rr will be ∌24.5\sim 24.5 (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg2^2 with ÎŽ<+34.5∘\delta<+34.5^\circ, and will be imaged multiple times in six bands, ugrizyugrizy, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg2^2 region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to r∌27.5r\sim27.5. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

    Multi-Locus Variable-Number Tandem Repeat Profiling of Salmonella enterica Serovar Typhi Isolates from Blood Cultures and Gallbladder Specimens from Makassar, South-Sulawesi, Indonesia

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    Multi-locus variable-number tandem repeat analysis differentiated 297 Salmonella enterica serovar Typhi blood culture isolates from Makassar in 76 genotypes and a single unique S. Typhi genotype was isolated from the cholecystectomy specimens of four patients with cholelithiasis. The high diversity in S. Typhi genotypes circulating in Makassar indicates that the number of carriers could be very large, which may complicate disease prevention and control

    Functional Myogenic Engraftment from Mouse iPS Cells

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    Direct reprogramming of adult fibroblasts to a pluripotent state has opened new possibilities for the generation of patient- and disease-specific stem cells. However the ability of induced pluripotent stem (iPS) cells to generate tissue that mediates functional repair has been demonstrated in very few animal models of disease to date. Here we present the proof of principle that iPS cells may be used effectively for the treatment of muscle disorders. We combine the generation of iPS cells with conditional expression of Pax7, a robust approach to derive myogenic progenitors. Transplantation of Pax7-induced iPS-derived myogenic progenitors into dystrophic mice results in extensive engraftment, which is accompanied by improved contractility of treated muscles. These findings demonstrate the myogenic regenerative potential of iPS cells and provide rationale for their future therapeutic application for muscular dystrophies
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