1,331 research outputs found

    Ground Water in the Kentucky River Basin

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    Most private wells in the Kentucky River Basin are in unconfined or semi-confined bedrock aquifers. Within these aquifers, high-yield zones are irregularly distributed. The most productive wells are drilled into fractured bedrock and alluvium along the Kentucky River floodplain. The data indicate that ground water acts as a buffer to peak and low flows in Kentucky River Basin streams. At current withdrawal rates, ground-water usage does not seem to have an adverse impact on the Kentucky River. Privately owned ground-water sources supply approximately 135,000 people living in the basin-approximately 19 percent of the total population and 36 percent of the rural population. More than 50 percent of residential water supplies in eastern Kentucky rely on ground water. If aquifers are protected from pollution by wellhead protection programs and old wells are retrofitted to prevent direct contamination, then ground water will continue to provide a reliable water supply in many rural areas of the basin. However, for most of the basin, few wells will have yields adequate to supply a large demand. Ground water from present wells will not provide an adequate supply for communities with a population of over a few thousand. Limited discharge data available for springs and large wells in the basin strongly suggest that the potential for ground water to supplement current supplies should not be ignored. Discharge from well fields and springs could be used to augment surface supplies during drought. A better understanding of the distribution and quality of ground-water resources is crucial for the citizens of the basin to fully benefit from ground water

    Ground-Water Quality in Kentucky: Fluoride

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    Fluoride (F-) is an ion of the element fluorine, and is a natural component in most water resources. According to Hem (1989), fluoride concentrations in fresh water are generally less than 1 mg/L (milligrams per liter), and the concentration of fluoride in the world\u27s oceans is about 1.3 mg/L. The source of most fluoride in natural fresh-water resources is various rocks and minerals in bedrock and sediments

    Temporal changes in prevalence of molecular markers mediating antimalarial drug resistance in a high malaria transmission setting in Uganda.

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    Standard therapy for malaria in Uganda changed from chloroquine to chloroquine + sulfadoxine-pyrimethamine in 2000, and artemether-lumefantrine in 2004, although implementation of each change was slow. Plasmodium falciparum genetic polymorphisms are associated with alterations in drug sensitivity. We followed the prevalence of drug resistance-mediating P. falciparum polymorphisms in 982 samples from Tororo, a region of high transmission intensity, collected from three successive treatment trials conducted during 2003-2012, excluding samples with known recent prior treatment. Considering transporter mutations, prevalence of the mutant pfcrt 76T, pfmdr1 86Y, and pfmdr1 1246Y alleles decreased over time. Considering antifolate mutations, the prevalence of pfdhfr 51I, 59R, and 108N, and pfdhps 437G and 540E were consistently high; pfdhfr 164L and pfdhps 581G were uncommon, but most prevalent during 2008-2010. Our data suggest sequential selective pressures as different treatments were implemented, and they highlight the importance of genetic surveillance as treatment policies change over time

    The Reliability of Global and Hemispheric Surface Temperature Records

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    The purpose of this review article is to discuss the development and associated estimation of uncertainties in the global and hemispheric surface temperature records. The review begins by detailing the groups that produce surface temperature datasets. After discussing the reasons for similarities and differences between the various products, the main issues that must be addressed when deriving accurate estimates, particularly for hemispheric and global averages, are then considered. These issues are discussed in the order of their importance for temperature records at these spatial scales: biases in SST data, particularly before the 1940s; the exposure of land-based thermometers before the development of louvred screens in the late 19th century; and urbanization effects in some regions in recent decades. The homogeneity of land-based records is also discussed; however, at these large scales it is relatively unimportant. The article concludes by illustrating hemispheric and global temperature records from the four groups that produce series in near-real time

    Drug susceptibility of Plasmodium falciparum in eastern Uganda: a longitudinal phenotypic and genotypic study

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    Background: Treatment and control of malaria depends on artemisinin-based combination therapies (ACTs) and is challenged by drug resistance, but thus far resistance to artemisinins and partner drugs has primarily occurred in southeast Asia. The aim of this study was to characterise antimalarial drug susceptibility of Plasmodium falciparum isolates from Tororo and Busia districts in Uganda. Methods: In this prospective longitudinal study, P falciparum isolates were collected from patients aged 6 months or older presenting at the Tororo District Hospital (Tororo district, a site with relatively low malaria incidence) or Masafu General Hospital (Busia district, a high-incidence site) in eastern Uganda with clinical symptoms of malaria, a positive Giemsa-stained blood film for P falciparum, and no signs of severe disease. Ex-vivo susceptibilities to ten antimalarial drugs were measured using a 72-h microplate growth inhibition assay with SYBR Green detection. Relevant P falciparum genetic polymorphisms were characterised by molecular methods. We compared results with those from earlier studies in this region and searched for associations between drug susceptibility and parasite genotypes. Findings: From June 10, 2016, to July 29, 2019, 361 P falciparum isolates were collected in the Busia district and 79 in the Tororo district from 440 participants. Of 440 total isolates, 392 (89%) successfully grew in culture and showed excellent drug susceptibility for chloroquine (median half-maximal inhibitory concentration [IC50] 20·0 nM [IQR 12·0-26·0]), monodesethylamodiaquine (7·1 nM [4·3-8·9]), pyronaridine (1·1 nM [0·7-2·3]), piperaquine (5·6 nM [3·3-8·6]), ferroquine (1·8 nM [1·5-3·3]), AQ-13 (24·0 nM [17·0-32·0]), lumefantrine (5·1 nM [3·2-7·7]), mefloquine (9·5 nM [6·6-13·0]), dihydroartemisinin (1·5 nM [1·0-2·0]), and atovaquone (0·3 nM [0·2-0·4]). Compared with results from our study in 2010-13, significant improvements in susceptibility were seen for chloroquine (median IC50 288·0 nM [IQR 122·0-607·0]; p\u3c0·0001), monodesethylamodiaquine (76·0 nM [44·0-137]; p\u3c0·0001), and piperaquine (21·0 nM [7·6-43·0]; p\u3c0·0001), a small but significant decrease in susceptibility was seen for lumefantrine (3·0 nM [1·1-7·6]; p\u3c0·0001), and no change in susceptibility was seen with dihydroartemisinin (1·3 nM [0·8-2·5]; p=0·64). Chloroquine resistance (IC50\u3e100 nM) was more common in isolates from the Tororo district (11 [15%] of 71), compared with those from the Busia district (12 [4%] of 320; p=0·0017). We showed significant increases between 2010-12 and 2016-19 in the prevalences of wild-type P falciparum multidrug resistance protein 1 (PfMDR1) Asn86Tyr from 60% (391 of 653) to 99% (418 of 422; p\u3c0·0001), PfMDR1 Asp1246Tyr from 60% (390 of 650) to 90% (371 of 419; p\u3c0·0001), and P falciparum chloroquine resistance transporter (PfCRT) Lys76Thr from 7% (44 of 675) to 87% (364 of 417; p\u3c0·0001). Interpretation: Our results show marked changes in P falciparum drug susceptibility phenotypes and genotypes in Uganda during the past decade. These results suggest that additional changes will be seen over time and continued surveillance of susceptibility to key ACT components is warranted. Funding: National Institutes of Health and Medicines for Malaria Venture

    Analysis of the modes of energy consumption of the complex of an incoherent scattering of the institute of ionosphere of national academy of sciences and the ministry of education and science of Ukraine

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    У даній статті представлені результати аналізу режимів енергоспоживання комплексу некогерентного розсіяння Інституту іоносфери НАН і МОН України з метою вирішення проблеми підвищення енергоефективності науково-дослідного комплексу та створення енергоефективної системи електропостачання, яка забезпечить стійку роботу наукового обладнання для виконання дослідницьких програм НАН України. Описана система електроживлення комплексу та режими енергоспоживання комплексу. Описано пристрої радарної системи, а також найбільш потужні споживачі електроенергії, які споживають електроенергію на експериментальні і господарські потреби. Проаналізовано енергоспоживання комплексу некогерентного розсіяння за 2013 р. Отримано і представлено графіки середньої споживаної потужності (середньодобовий показник) і середньої споживаної потужності в режимі вимірювань. Описана доцільність проведення робіт з оптимізації енергопостачання науково-дослідного комплексу Інституту іоносфери. Запропоновано можливі заходи для зниження економічної вартості проведення експериментів з дослідження іоносфери науково-дослідного комплексу некогерентного розсіяння. Проведено аналіз робіт сучасних авторів з метою показати, що підвищення ефективності функціонування систем електропостачання є актуальною проблемою сучасних досліджень.This article presents the results of the analysis of the energy consumption modes of the incoherent scattering complex of the Institute of Ionosphere of the National Academy of Sciences and the Ministry of Education and Science of Ukraine to solve the problem of increasing the energy efficiency of a research complex and creating an energy efficient power supply system that will ensure the sustainability of scientific equipment for research programs of the National Academy of Sciences of Ukraine. The system of power supply of the complex and modes of power consumption of the complex are described. The devices of the radar system are described, as well as the most powerful consumers of electricity, which consume electricity for experimental and economic needs. The energy consumption of the incoherent scattering complex in 2013 is analyzed. Graphs of the average power consumption (daily average) and average power consumption in measurement modes were obtained and presented. The feasibility of work to optimize the energy supply of the research complex of the institute of the ionosphere is described. Possible measures are proposed to reduce the economic cost of conducting experiments on the study of the ionosphere of an incoherent scattering research complex. The analysis of the works of modern authors i s carried out in order to show that increasing the efficiency of the power supply systems is an actual problem of modern research

    Similarity in Recombination Rate Estimates Highly Correlates with Genetic Differentiation in Humans

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    Recombination varies greatly among species, as illustrated by the poor conservation of the recombination landscape between humans and chimpanzees. Thus, shorter evolutionary time frames are needed to understand the evolution of recombination. Here, we analyze its recent evolution in humans. We calculated the recombination rates between adjacent pairs of 636,933 common single-nucleotide polymorphism loci in 28 worldwide human populations and analyzed them in relation to genetic distances between populations. We found a strong and highly significant correlation between similarity in the recombination rates corrected for effective population size and genetic differentiation between populations. This correlation is observed at the genome-wide level, but also for each chromosome and when genetic distances and recombination similarities are calculated independently from different parts of the genome. Moreover, and more relevant, this relationship is robustly maintained when considering presence/absence of recombination hotspots. Simulations show that this correlation cannot be explained by biases in the inference of recombination rates caused by haplotype sharing among similar populations. This result indicates a rapid pace of evolution of recombination, within the time span of differentiation of modern humans
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