Low temperature specific heat of vanadium carbide

Low temperature specific heat measurements on vanadium carbide crystal

Direct epitaxial growth of submicron-patterned SiC structures on Si(001)

We report on the direct epitaxial growth of submicron-patterned SiC structures on Si(001) substrates using supersonic molecular jet epitaxy and resistless e-beam lithography. Prior to SiC film growth, an electron beam was scanned on hydrogen-passivated Si substrates in order to produce silicon oxide lines with widths greater than or equal to 60 nm. The SiC nucleation and growth rates were significantly reduced on the oxidized regions during the subsequent supersonic jet epitaxial growth of SiC, which yielded epitaxial, submicron-patterned SiC films. The, effects of the growth temperature and e-beam dose on the SiC growth and pattern linewidth are discussed. (C) 1999 American Vacuum Society. [S0734-211X(99)00906-3].open113sciescopu

Reconciling Gaussian plume and Computational Fluid Dynamics models of particulate dispersion

Computational Fluid Dynamics (CFD) is increasingly used to model particulate dispersion in situations where Gaussian Dispersion models are inappropriate or inaccurate. However, there is evidence which indicates that many CFD models under-predict lateral plume spread. This paper aims to address this by imple- menting a strategy which incorporates wind direction variability into CFD models using a formulation which is also used in the UK-ADMS plume spread module. In the present work, a series of CFD simulations are run at various wind angles. The outputs from these simulations are weighted using a Gaussian probability density function and combined to produce a plume. The standard k−ε model has been employed to solve the RANS equations of the flow field for stable, neutral and unstable atmospheric stabilities, coupled with the Lagrangian Particle tracking model to model dispersion. By comparing the CFD accretion profiles to UK-ADMS dry deposition results, it is observed that the proposed modelling methodology produces lateral spreading of the plume which is comparable to that obtained using UK-ADMS. However, the Lagrangian integral time scale constant, c L , which governs the influence turbulence has on the dispersion, must also be modified to bring absolute values of accretion rates in line with those observed in UK-ADMS

Can remote STI/HIV testing and eClinical Care be compatible with robust public health surveillance?

In this paper we outline the current data capture systems for human immunodeficiency virus (HIV) and sexually transmitted infection (STI) surveillance used by Public Health England (PHE), and how these will be affected by the introduction of novel testing platforms and changing patient pathways. We outline the Chlamydia Online Clinical Care Pathway (COCCP), developed as part of the Electronic Self-Testing for Sexually Transmitted Infections (eSTI(2)) Consortium, which ensures that surveillance data continue to be routinely collected and transmitted to PHE. We conclude that both novel diagnostic testing platforms and established data capture systems must be adaptable to ensure continued robust public health surveillance

Effective Vortex Pinning in MgB2 thin films

We discuss pinning properties of MgB2 thin films grown by pulsed-laser deposition (PLD) and by electron-beam (EB) evaporation. Two mechanisms are identified that contribute most effectively to the pinning of vortices in randomly oriented films. The EB process produces low defected crystallites with small grain size providing enhanced pinning at grain boundaries without degradation of Tc. The PLD process produces films with structural disorder on a scale less that the coherence length that further improves pinning, but also depresses Tc

Prospects for local co-governance

British local authorities and their partners are increasingly developing new ways of working together with local communities. The nature of this co-working, however, is complex, multi-faceted and little understood. This article argues for greater clarity of thinking on the topic, by analysing this co-working as a form of political co-governance, and drawing attention in particular to issues of scale and democracy. Using evidence from a study of 43 local authority areas, 16 authorities are identified where co-governance is practised, following three main types of approach: service-influencing, service-delivering and parish council developing. It is concluded that strengthening political co-governance is essential for a healthy democracy

Interpreting planners' talk about change: An exploratory study.

Talk by planners about major changes (‘reform’) in a particular planning regime is the focus of this article. Change in planning in the United Kingdom has been a recurrent theme in planning practice and research. However, there is little looking at practitioners both in the public and the private sectors in relation to change. Also, theory development has been limited and the interpretive link between institutional change, organisational change and planners’ situated agency could be strengthened. This article aims to add new dimensions to the current debate by looking at planners in both the public and the private sectors in Wales; by adopting a more open-ended approach requiring planners to generate ideas and display a perspective on planning; and by linking theories of institutional and organisational change with the model of actors’ agency developed by Bevir and Rhodes to form an interpretive frame. With reflections stemming from an exploratory case in Wales, the article seeks also to contribute to debates on planning in the United Kingdom and beyond, reaching to new-institutionalist theory and interpretive ontologie

Influence of Glutathione S-Transferase Polymorphisms on Cognitive Functioning Effects Induced by p,p′-DDT among Preschoolers

5 pages, 4 tables.-- PMID: 19057715 [PubMed].-- PMCID: PMC2592282.-- Printed version published Nov 2008.Background Early-life exposure to p,p′-DDT [2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane] is associated with a decrease in cognitive skills among preschoolers at 4 years of age. We hypothesized that genetic variability in glutathione S-transferase (GST) genes (GSTP1, GSTM1, and GSTT1) could influence the effects of prenatal exposure to p,p′-DDT.Methods We used data from 326 children assessed in a prospective population-based birth cohort at the age of 4 years. In that study, the McCarthy Scales of Children’s Abilities were administrated by psychologists, organochlorine compounds were measured in cord serum, and genotyping was conducted for the coding variant Ile105Val from GSTP1 and for null alleles from GSTM1 and GSTT1. We used linear regression models to measure the association between organochlorines and neurodevelopmental scores by GST polymorphisms.Results p,p′-DDT cord serum concentration was inversely associated with general cognitive, memory, quantitative, and verbal skills, as well as executive function and working memory, in children who had any GSTP1 Val-105 allele. GSTP1 polymorphisms and prenatal p,p′-DDT exposure showed a statistically significant interaction for general cognitive skills (p = 0.05), quantitative skills (p = 0.02), executive function (p = 0.01), and working memory (p = 0.02). There were no significant associations between p,p′-DDT and cognitive functioning at 4 years of age according to GSTM1 and GSTT1 polymorphisms.Conclusions Results indicate that children with GSTP1 Val-105 allele were at higher risk of the adverse cognitive functioning effects of prenatal p,p′-DDT exposure.This study was funded by grants from the Spanish Ministry of Health (FIS-PI041436, FIS-PI041705, FIS-PI051187), Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041), and Ciber en Epidemiología y Salud Pública, the Generalitat de Catalunya-CIRIT (Consejo Interdepartmental de Investigación e Innovación de Cataluña) (1999SGR 00241), and Genome Spain.Peer reviewe

Strongly Enhanced Current Densities in Superconducting Coated Conductors of YBa2Cu3O7-x + BaZrO3

There are numerous potential applications for superconducting tapes, based on YBa2Cu3O7-x (YBCO) films coated onto metallic substrates. A long established goal of more than 15 years has been to understand the magnetic flux pinning mechanisms which allow films to maintain high current densities out to high magnetic fields. In fact, films carry 1-2 orders of magnitude higher current densities than any other form of the material. For this reason, the idea of further improving pinning has received little attention. Now that commercialisation of conductors is much closer, for both better performance and lower fabrication costs, an important goal is to achieve enhanced pinning in a practical way. In this work, we demonstrate a simple and industrially scaleable route which yields a 1.5 to 5-fold improvement in the in-field current densities of already-high-quality conductors

Heterogeneity of the HIV epidemic in the general population of Karnataka state, south India

<p>Abstract</p> <p>Background</p> <p>In the context of <it>AVAHAN</it>, the India AIDS Initiative of the Bill & Melinda Gates Foundation, general population surveys (GPS) were carried out between 2006 and 2008 in Belgaum (northern), Bellary (mid-state) and Mysore (southern) districts of Karnataka state, south India. Data from these three surveys were analysed to understand heterogeneity in HIV risk.</p> <p>Methods</p> <p>Outcome variables were the prevalence of HIV and sexually transmitted infections (STIs). Independent variables included age, district, place of residence, along with socio-demographic, medical and behavioural characteristics. Multivariate logistic regression was undertaken to identify characteristics associated with HIV and differences between districts, incorporating survey statistics to consider weights and cluster effects.</p> <p>Results</p> <p>The participation rate was 79.0% for the interview and 72.5% for providing a blood or urine sample that was tested for HIV. Belgaum had the highest overall HIV (1.43%) and <it>Herpes simplex</it> type-2 (HSV-2) (16.93%) prevalence, and the lowest prevalence of curable STIs. In Belgaum, the HIV epidemic is predominantly rural, and among women. In Bellary, the epidemic is predominantly in urban areas and among men, and HIV prevalence was 1.18%. Mysore had the lowest prevalence of HIV (0.80%) and HSV-2 (10.89%) and the highest prevalence of curable STIs. Higher HIV prevalence among men was associated with increasing age (p<0.001), and with history of STIs (AOR=2.44,95%CI:1.15-5.17). Male circumcision was associated with lower HIV prevalence (AOR=0.33,95%CI:0.13-0.81). Higher HIV prevalence among women was associated with age (AOR_25-29years=11.22,95%CI:1.42-88.74, AOR_30-34years=13.13,95%CI:1.67-103.19 and AOR_35-39years=11.33,95%CI:1.32-96.83), having more than one lifetime sexual partner (AOR=4.61,95%CI:1.26-16.91) and having ever used a condom (AOR=3.32,95%CI:1.38-7.99). Having a dissolved marriage (being widowed/divorced/separated) was the strongest predictor (AOR=10.98,95%CI: 5.35-22.57) of HIV among women. Being a muslim woman was associated with lower HIV prevalence (AOR=0.27,95%CI:0.08-0.87).</p> <p>Conclusion</p> <p>The HIV epidemic in Karnataka shows considerable heterogeneity, and there appears to be an increasing gradient in HIV prevalence from south to north. The sex work structure in the northern districts may explain the higher prevalence of HIV in northern Karnataka. The higher prevalence of HIV and HSV-2 and lower prevalence of curable STIs in Belgaum suggests a later epidemic phase. Similarly, higher prevalence of curable STIs and lower HIV and HSV-2 prevalence in Mysore suggests an early phase epidemic.</p