1,272 research outputs found
Colloid-oil-water-interface interactions in the presence of multiple salts: charge regulation and dynamics
We theoretically and experimentally investigate colloid-oil-water-interface
interactions of charged, sterically stabilized, poly(methyl-methacrylate)
colloidal particles dispersed in a low-polar oil (dielectric constant
) that is in contact with an adjacent water phase. In this model
system, the colloidal particles cannot penetrate the oil-water interface due to
repulsive van der Waals forces with the interface whereas the multiple salts
that are dissolved in the oil are free to partition into the water phase. The
sign and magnitude of the Donnan potential and/or the particle charge is
affected by these salt concentrations such that the effective interaction
potential can be highly tuned. Both the equilibrium effective colloid-interface
interactions and the ion dynamics are explored within a Poisson-Nernst-Planck
theory, and compared to experimental observations.Comment: 13+2 pages, 5+3 figures; V2: small clarifications in the tex
Effectiveness of Large Scale Water and Sanitation Interventions: the One Million Initiative in Mozambique
The One Million Initiative aims for 70% of the population using safe drinking water and 50% using improved sanitation in 18 districts in three provinces of central Mozambique. This paper evaluates health effects of the initiative using a panel survey, analyzing the contributions of latrine ownership, hand washing, and use of improved water sources to health. It is unique in providing rigorous evaluation of such a large scale WASH program. The authors find a large impact of CLTS on adults and older children, and a similar impact in improved water sources on health of young children
Geo-additive models of Childhood Undernutrition in three Sub-Saharan African Countries
We investigate the geographical and socioeconomic determinants of childhood undernutrition in Malawi, Tanzania and Zambia, three neighboring countries in Southern Africa using the 1992 Demographic and Health Surveys. We estimate models of undernutrition jointly for the three countries to explore regional patterns of undernutrition that transcend boundaries, while allowing for country-specific interactions. We use semiparametric models to flexibly model the effects of selected so-cioeconomic covariates and spatial effects. Our spatial analysis is based on a flexible geo-additive model using the district as the geographic unit of anal-ysis, which allows to separate smooth structured spatial effects from random effect. Inference is fully Bayesian and uses recent Markov chain Monte Carlo techniques. While the socioeconomic determinants generally confirm what is known in the literature, we find distinct residual spatial patterns that are not explained by the socioeconomic determinants. In particular, there appears to be a belt run-ning from Southern Tanzania to Northeastern Zambia which exhibits much worse undernutrition, even after controlling for socioeconomic effects. These effects do transcend borders between the countries, but to a varying degree. These findings have important implications for targeting policy as well as the search for left-out variables that might account for these residual spatial patterns
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Athermal colorless C-band optical transmitter system for passive optical networks
This paper reports an uncooled transmitter system using a digital super-mode (DS) distributed Bragg reflector (DBR) tunable laser, which is able to act as an athermal, wavelength agnostic transmitter suitable for wavelength division multiplexed (WDM) passive optical network (PON) applications. An open-loop laser current control algorithm is designed to compensate autonomously for wavelength drift, thus allowing constant operating wavelength to be achieved regardless of ambient temperature. An improved wavelength accuracy of ±3 GHz is achieved when using low bandwidth feedback from the central office using information from a centralized shared wavelength locker. The entire laser start-up, channel selection and subsequent wavelength control is autonomous and has been implemented on micro-controllers and field programmable gate arrays. We demonstrate a three channel WDM-PON system comprising an uncooled packaged DS-DBR laser in the presence of two neighboring interfering channels. Error free transmission over 40 km single mode fiber of 10 Gb/s externally modulated NRZ data, is achieved for each of 48 C-band channels on the 100 GHz ITU grid. Successful athermal operation is demonstrated by sweeping the ambient temperature of the laser from 15 to 70 °C with a maximum wavelength deviation for any channel of no more than 0.1 nm.This work has been supported by the Technology Strategy Board, UK and by the German ministry for education and research, through the EU ERA-NET+ projects PIANO+ IMPACT (BMBF grant: 13N11434) and TUCAN (BMBF grant: 13N11573). We also acknowledge the support of the UK Engineering and Physical Sciences Research Council via the INTERNET project.This is the final version of the article. It first appeared from IEEE via http://dx.doi.org/10.1109/JLT.2014.235405
Syndromic surveillance of abortions in beef cattle based on the prospective analysis of spatio-temporal variations of calvings
О финансово-экономическом кризисе
У статті для визначення позиції молодих учених, стосовно фінансово-економічної кризи 2008–2010 р. використаний метод нечіткої кластеризації даних, що працює в режимі паралельної їхньої обробки. Наведено заходи щодо зниження наслідків кризи для України.В статье для определения позиции молодых ученых, применительно к финансово-экономическому кризису 2008—2010 гг. использован метод нечеткой кластеризации данных, который работает в режиме параллельной их обработки. Приведены мероприятия по снижению последствий кризиса для Украины.In an article for determining the position of young scientists, in relation to financial and economic crisis, 2008— 2010. used the method of fuzzy clustering, which operates in parallel processing. Shows the measures to reduce the impact of the crisis in Ukraine
Exploring pig trade patterns to inform the design of risk-based disease surveillance and control strategies
An understanding of the patterns of animal contact networks provides essential information for the design of risk-based animal disease surveillance and control strategies. This study characterises pig movements throughout England and Wales between 2009 and 2013 with a view to characterising spatial and temporal patterns, network topology and trade communities. Data were extracted from the Animal and Plant Health Agency (APHA)’s RADAR (Rapid Analysis and Detection of Animal-related Risks) database, and analysed using descriptive and network approaches. A total of 61,937,855 pigs were moved through 872,493 movements of batches in England and Wales during the 5-year study period. Results show that the network exhibited scale-free and small-world topologies, indicating the potential for diseases to quickly spread within the pig industry. The findings also provide suggestions for how risk-based surveillance strategies could be optimised in the country by taking account of highly connected holdings, geographical regions and time periods with the greatest number of movements and pigs moved, as these are likely to be at higher risk for disease introduction. This study is also the first attempt to identify trade communities in the country, information which could be used to facilitate the pig trade and maintain disease-free status across the country in the event of an outbreak
Mapping genetic determinants of host susceptibility to Pseudomonas aeruginosa lung infection in mice.
Background: P. aeruginosa is one of the top three causes of opportunistic human bacterial infections. The remarkable
variability in the clinical outcomes of this infection is thought to be associated with genetic predisposition. However,
the genes underlying host susceptibility to P. aeruginosa infection are still largely unknown.
Results: As a step towards mapping these genes, we applied a genome wide linkage analysis approach to a mouse
model. A large F2 intercross population, obtained by mating P. aeruginosa-resistant C3H/HeOuJ, and susceptible A/J
mice, was used for quantitative trait locus (QTL) mapping. The F2 progenies were challenged with a P. aeruginosa
clinical strain and monitored for the survival time up to 7 days post-infection, as a disease phenotype associated trait.
Selected phenotypic extremes of the F2 distribution were genotyped with high-density single nucleotide polymorphic
(SNP) markers, and subsequently QTL analysis was performed. A significant locus was mapped on chromosome 6 and
was named P. aeruginosa infection resistance locus 1 (Pairl1). The most promising candidate genes, including Dok1,
Tacr1, Cd207, Clec4f, Gp9, Gata2, Foxp1, are related to pathogen sensing, neutrophils and macrophages recruitment and
inflammatory processes.
Conclusions: We propose a set of genes involved in the pathogenesis of P. aeruginosa infection that may be explored
to complement human studie
Focus on focus: Lack of coherence between systemic and microvascular indices of oedema formation
Background: Fluid therapy remains a cornerstone of therapy in shock states. However, fluid overloading ultimately results in oedema formation which is related to excess morbidity and mortality. Handheld microscopes are now frequently used to study the sublingual microcirculation. As a corollary, these devices measure focal distance, or surface to capillary distance. Physiologically, this could represent a microvascular index of oedema formation and could have the potential to guide fluid therapy. This potential tool should be investigated, especially given the frequently reported lack of coherence between systemic and microvascular parameters in the critically ill. Therefore, we set out to assess the correlation between microvascular focal distance and systemic indices of oedema formation, specifically fluid balance and weight gain. Methods: Following ex vivo testing of focal distance measurement reliability, we conducted a prospective observational cohort study in patients admitted to the intensive care unit of our university teaching hospital. We determined surface to capillary distance using sidestream dark field (SDF) and incident dark field (IDF) imaging by assessing the focal distance point or object distance range at which a sharp recording could be made. Measurements were performed in post-cardiac surgery patients and in patients following emergency admission at two time points separated by at least several hours. Data on fluid balance, weight and weight gain were collected simultaneously. Results: Sixty patients were included. The focal setting, focus point for SDF and the object distance range for IDF did not differ significantly between time points. Focus was not correlated with difference in fluid balance or weight gain. Conclusions: There is a lack of coherence between surface to capillary distance as determined by SDF or IDF imaging and fluid balance or weight gain. Thus, focal distance as a microvascular index of oedema formation cannot currently be used as a proxy for systemic indices of oedema formation. However, given the lack of coherence, further research should determine whether focal distance may provide better guidance for fluid therapy than traditional markers of overzealous fluid administration
Trans-eQTLs Reveal That Independent Genetic Variants Associated with a Complex Phenotype Converge on Intermediate Genes, with a Major Role for the HLA
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