2,821 research outputs found
Transient cavities and the excess chemical potentials of hard-spheroid solutes in dipolar hard sphere solvents
Monte Carlo computer simulations are used to study transient cavities and the
solvation of hard-spheroid solutes in dipolar hard sphere solvents. The
probability distribution of spheroidal cavities in the solvent is shown to be
well described by a Gaussian function, and the variations of fit parameters
with cavity elongation and solvent properties are analyzed. The excess chemical
potentials of hard-spheroid solutes with aspect ratios in the range , and with volumes between one and twenty times that of a solvent
molecule, are presented. It is shown that for a given molecular volume and
solvent dipole moment (or temperature) a spherical solute has the lowest excess
chemical potential and hence the highest solubility, while a prolate solute
with aspect ratio should be more soluble than an oblate solute with aspect
ratio . For a given solute molecule, the excess chemical potential
increases with increasing temperature; this same trend is observed in the case
of hydrophobic solvation. To help interpret the simulation results, comparison
is made with a scaled-particle theory that requires prior knowledge of a
solute-solvent interfacial tension and the pure-solvent equation of state,
which parameters are obtained from simulation results for spherical solutes.
The theory shows excellent agreement with simulation results over the whole
range of solute elongations considered.Comment: 10 pages, 10 figure
Suitability of Flood Hazard Assessment Methods for Tanzania: A Case of Little Ruaha and Upper Ngerengere Catchment
Understanding the applicability of flood quantile estimation methods in flood hazard assessment is fundamental for planning, prevention, and management of flood risks. Therefore, this study evaluates and compares three hydrological methods, namely Hydrologiska ByrĂĽns Vattenbalansavdelning (HBV), Soil Conservation Service-Curve Number (SCS-CN), and regional regression equation (RRE), to estimate flood quantiles embedded in the existing flood damage assessment framework by applying them to two different river catchments, Little Ruaha (LR) and Upper Ngerengere (UN), Tanzania. The evaluation of method performance was carried out using three standard statistical measures for data from 1954 to 2010 and the 1971â1988 period in LR and UN catchments (LRC and UNC). The findings indicated that no single approach could fit all catchments and return periods for these case studies. Overall performance indicated that the RRE method provides more accurate and consistent quantile estimates than other approaches. These findings indicate that spatial scale, model structure, parameters, and hydro-climatic data condition are the most important elements influencing the suitability of the supplied methods for flood risk assessments, which serve as the foundation for developing an improved flood damage assessment framework.
Keywords: Flood Quantiles; Estimate Methods; Flood Risk Management; Little Ruaha; Ngerenger
Use of rapid diagnostic tests in malaria school surveys in Kenya: does their under-performance matter for planning malaria control?
Malaria rapid diagnostic tests (RDTs) are known to yield false-positive results, and their use in epidemiologic surveys will overestimate infection prevalence and potentially hinder efficient targeting of interventions. To examine the consequences of using RDTs in school surveys, we compared three RDT brands used during a nationwide school survey in Kenya with expert microscopy and investigated the cost implications of using alternative diagnostic approaches in identifying localities with differing levels of infection. Overall, RDT sensitivity was 96.1% and specificity was 70.8%. In terms of classifying districts and schools according to prevalence categories, RDTs were most reliable for the 40% categories and least reliable in the 1-4.9% category. In low-prevalence settings, microscopy was the most expensive approach, and RDT results corrected by either microscopy or polymerase chain reaction were the cheapest. Use of polymerase chain reaction-corrected RDT results is recommended in school malaria surveys, especially in settings with low-to-moderate malaria transmission
Successful IVF-ICSI with live baby in an azoospermic patient with cryopreserved sperms: Case report
Male factor is one of the most frequent cause of infertility and presents a variety of endocrine, genetic and immunological etiologies, as well as sexual malfunction, varicocele and genital infections. A case of a couple with primary infertilityfor two years is presented. Both partners were evaluated thoroughly, with a finding of male infertility. The man was found to be azoospermic after two semenalysis were performed. The Follicle Stimulating hormone (FSH) was raised with low testosterone levels indicating testicular failure. The recommended treatment was testicular biopsy with cryopreservation of the sperm and subsequent Intra cytoplasmic Sperm Injection (ICSI). This treatment option was undertaken with successful implantation and live baby delivery. The case study presents the diagnostic modalities and management of male infertility with azoospermia
Internal Energy of the Potts model on the Triangular Lattice with Two- and Three-body Interactions
We calculate the internal energy of the Potts model on the triangular lattice
with two- and three-body interactions at the transition point satisfying
certain conditions for coupling constants. The method is a duality
transformation. Therefore we have to make assumptions on uniqueness of the
transition point and that the transition is of second order. These assumptions
have been verified to hold by numerical simulations for q=2, 3 and 4, and our
results for the internal energy are expected to be exact in these cases.Comment: 9 pages, 4 figure
Premature ovarian failure in twins: case report
Premature ovarian failure (POF)is a serious life-changing condition that affects young women, remains an enigma and the researchersâ challenge. POF, premature ovarian insufficiency (POI), premature menopause, premature dysfunction (POD), or hypergonadotropic hypogonadism is one of the most perplexing disorders with aheterogeneous origin. Infertility, social and psychological stress are common consequences of this entity. This paper presents a rare condition where both twins had presented with POF
Community Knowledge and Perceptions on National School-Based De-Worming Programme
Objectives: To determine the community level of knowledge, attitude and perception of soil transmitted helminthes and the national school-based de-worming programme in selected villages of Busia County in Kenya. Design: A cross-sectional survey. Setting: Busia and Bunyala districts in Busia County. Subjects: A total of 384 participants were studied. Main outcome measures: Socio-demographic characteristics, then knowledge, causes and effects of Soil Transmitted Infections on health and education, prevention strategies, knowledge of national school-based de-worming programming, implementing strategies of the programme, benefits of the programme, community satisfaction and health seeking behaviour. Results: Eating the uncooked food as a cause for soil transmitted infections constituted 27.16% (63) followed by 16.38% (38) not using latrines, 15.95% (37) eating left over foods, 12.93% (30) eating cold food, 10.78% (25) eating not well cooked pork, 9.48% (22) eating contaminated soil, and 7.33% (17) changing of diet. One head teacher interviewed stated that âOne can be able to notice if his/her child has worm infection if the child eats without getting satisfied, eating all the time and yet his belly is big.âCommunity Health Extension Worker in the FGD stated that: âDuring floods seasons most of the areas in Budalangi become flooded and all latrines are filled with water and the excreta start overflowing. Most of the residents donât have shoes especially the children and therefore they are prone to the worm infection.â99.57% of the parents were aware of the national school based de-worming programme of which (92%) learnt about the programme after their children were de-wormed in their various schools. Seventy five percent (174) were satisfied about the programme; 65.1% (151) and 10.3% indicated that the programme improves the childrenâs health and studentâs school performance respectively. Conclusion: Most of the parents do not have adequate knowledge on worms, their causes and signs and symptoms of the intestinal worms. Low educational levels and poverty levels also contribute to the lack of awareness on intestinal worms and putting the prevention measures across the board. The study also found out that the community perception towards the de-worming programme was good because the de-worming programme improved the childrenâs health and performance in education
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