Spacelike surfaces with free boundary in the Lorentz-Minkowski space

We investigate a variational problem in the Lorentz-Minkowski space \l^3 whose critical points are spacelike surfaces with constant mean curvature and making constant contact angle with a given support surface along its common boundary. We show that if the support surface is a pseudosphere, then the surface is a planar disc or a hyperbolic cap. We also study the problem of spacelike hypersurfaces with free boundary in the higher dimensional Lorentz-Minkowski space \l^{n+1}.Comment: 16 pages. Accepted in Classical and Quantum Gravit

The kinetics of hot-pressing for undoped and donor-doped BaTiO 3 ceramics

The kinetics of hot-pressing for undoped and donor-doped BaTiO 3 of high purity have been studied at 1050‡ C and at 2.3 to 27.6 MPa in an oxidizing atmosphere. The stress exponent and grain size exponent of the densification rate are indicative of control of densification by a grain boundary diffusion mechanism. The activation enthalpy (∼400 kJ mol −1 ) for the densification process has been measured over the range of 1050 to 1 200‡ C. No significant influence of the donor is observed on the densification of BaTiO 3 until the late stages of sintering.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44696/1/10853_2004_Article_BF00585460.pd

Blood spots as an alternative to whole blood collection and the effect of a small monetary incentive to increase participation in genetic association studies

<p>Abstract</p> <p>Background</p> <p>Collection of buccal cells from saliva for DNA extraction offers a less invasive and convenient alternative to venipuncture blood collection that may increase participation in genetic epidemiologic studies. However, dried blood spot collection, which is also a convenient method, offers a means of collecting peripheral blood samples from which analytes in addition to DNA can be obtained.</p> <p>Methods</p> <p>To determine if offering blood spot collection would increase participation in genetic epidemiologic studies, we conducted a study of collecting dried blood spot cards by mail from a sample of female cancer cases (n = 134) and controls (n = 256) who were previously selected for a breast cancer genetics study and declined to provide a venipuncture blood sample. Participants were also randomized to receive either a $2.00 bill or no incentive with the blood spot collection kits.</p> <p>Results</p> <p>The average time between the venipuncture sample refusal and recruitment for the blood spot collection was 4.4 years. Thirty-seven percent of cases and 28$2.00 incentive vs. 26% for no incentive, p = 0.6), it was significantly associated with participation among the breast cancer cases (48% vs. 27%, respectively, p = 0.01). There did not appear to be any bias in response since no differences between cases and controls and incentive groups were observed when examining several demographic, work history and radiation exposure variables.</p> <p>Conclusion</p> <p>This study demonstrates that collection of dried blood spot cards in addition to venipuncture blood samples may be a feasible method to increase participation in genetic case-control studies.</p

Association between knowledge, risk behaviours, and testing for sexually transmitted infections among men who have sex with men: findings from a large online survey in the United Kingdom.

OBJECTIVES: In the UK, men who have sex with men (MSM) bear a disproportionate sexually transmitted infection (STI) burden. We investigated MSM's STI knowledge; whether their STI testing behaviour met national guidelines (annually if sexually active; 3-monthly if engaging in STI risk behaviours); and the relationship between STI testing in the last 3 months, STI knowledge and STI risk behaviours by HIV status. METHODS: Sexually active (in the last year) men aged > 15 years who were UK residents and were recruited from gay-orientated online dating platforms completed an anonymous online survey about STI knowledge, STI risk behaviours, and STI testing (March-May 2017). This included 11 true statements about STIs. Respondents scored 1 for each statement they 'knew', with those scoring < 6 overall treated as having 'poor' STI knowledge. Descriptive and multivariable analyses were conducted, separately by HIV status, to test our hypothesis and calculate adjusted odds ratios (AORs) with 95% confidence intervals (CIs). RESULTS: Compared to HIV-positive men (n = 489), the proportion of HIV-negative/unknown-status men (n = 3157) with 'poor' STI knowledge was significantly higher (46.4% versus 22.9% for HIV-positive men) and the proportion with STI testing in the last 12 months was lower (71.6% versus 87.2%, respectively). In the last 3 months, 56.9% of HIV-negative/unknown-status and 74.1% of HIV-positive men reported STI risk behaviours, of whom 45.8% and 55.1%, respectively, had been tested for STIs during this time. Among HIV-negative/unknown-status men, those reporting STI risk behaviours were more likely (AOR 1.52; 95% CI 1.26-1.84) and those with poor STI knowledge less likely (AOR 0.73; 95% CI 0.61-0.89) to have been tested during the last 3 months. However, neither factor was independently associated with 3-monthly testing among HIV-positive men. CONCLUSIONS: Improving STI knowledge, especially among HIV-negative/unknown-status men, and promoting frequent STI testing among men engaging in STI risk behaviours are vital to address the poor sexual health of MSM

The Dynamic Landscape of Novel Psychoactive Substance (NPS) Use in Ireland: Results from an Expert Consultation

In Ireland, legislators encountered a new phenomenon in 2005 onwards with the advent of ‘legal highs’ sold in headshops. Use of ‘legal highs’ containing herbal and synthetic new psychoactive substances (NPS) was not confined to problematic drug users, and included social recreational users. Legislative controls were enacted in 2010, 2011 and 2015. The study aimed to investigate expert perspectives on the NPS situation with regard to changing and emergent trends in use, health and social consequences and service implications. This brief report presents descriptive findings from a national consultation using a structured guide with experts in 2016. Four themes emerged and centred on; ‘Definitions of NPS used within Professional Roles’; ‘Professional Experiences of NPS‘; ‘Types of NPS Users, Sourcing and Consequences of Use’; and ‘Service Response.’ Findings underscored the mental health and addiction related consequences of NPS use, with prevention, clinical and treatment services ill- equipped to deal with the particular characteristics of this form of drug abuse. Enhanced strategies, services and clinical responses are warranted to address the challenges encountered. © 2016 Springer Science+Business Media New Yor

HIV-1 co-receptor usage:influence on mother-to-child transmission and pediatric infection

Viral CCR5 usage is not a predictive marker of mother to child transmission (MTCT) of HIV-1. CXCR4-using viral variants are little represented in pregnant women, have an increased although not significant risk of transmission and can be eventually also detected in the neonates. Genetic polymorphisms are more frequently of relevance in the child than in the mother. However, specific tissues as the placenta or the intestine, which are involved in the prevalent routes of infection in MTCT, may play an important role of selective barriers

Mupirocin-resistant Staphylococcus aureus in Africa: a systematic review and meta-analysis

Background Mupirocin is widely used for nasal decolonization of Staphylococcus aureus to prevent subsequent staphylococcal infection in patients and healthcare personnel. However, the prolonged and unrestricted use has led to the emergence of mupirocin-resistant (mupR) S. aureus. The aim of this systematic review was to investigate the prevalence, phenotypic and molecular characteristics, and geographic spread of mupR S. aureus in Africa. Methods We examined five electronic databases (EBSCOhost, Google Scholar, ISI Web of Science, MEDLINE, and Scopus) for relevant English articles on screening for mupR S. aureus from various samples in Africa. In addition, we performed random effects meta-analysis of proportions to determine the pooled prevalence of mupR S. aureus in Africa. The search was conducted until 3 August 2016. Results We identified 43 eligible studies of which 11 (26%) were obtained only through Google Scholar. Most of the eligible studies (28/43; 65%) were conducted in Nigeria (10/43; 23%), Egypt (7/43; 16%), South Africa (6/43; 14%) and Tunisia (5/43; 12%). Overall, screening for mupR S. aureus was described in only 12 of 54 (22%) African countries. The disk diffusion method was the widely used technique (67%; 29/43) for the detection of mupR S. aureus in Africa. The mupA-positive S. aureus isolates were identified in five studies conducted in Egypt (n = 2), South Africa (n = 2), and Nigeria (n = 1). Low-level resistance (LmupR) and high-level resistance (HmupR) were both reported in six human studies from South Africa (n = 3), Egypt (n = 2) and Libya (n = 1). Data on mupR-MRSA was available in 11 studies from five countries, including Egypt, Ghana, Libya, Nigeria and South Africa. The pooled prevalence (based on 11 human studies) of mupR S. aureus in Africa was 14% (95% CI =6.8 to 23.2%). The proportion of mupA-positive S. aureus in Africa ranged between 0.5 and 8%. Furthermore, the frequency of S. aureus isolates that exhibited LmupR, HmupR and mupR-MRSA in Africa were 4 and 47%, 0.5 and 38%, 5 and 50%, respectively. Conclusions The prevalence of mupR S. aureus in Africa (14%) is worrisome and there is a need for data on administration and use of mupirocin. The disk diffusion method which is widely utilized in Africa could be an important method for the screening and identification of mupR S. aureus. Moreover, we advocate for surveillance studies with appropriate guidelines for screening mupR S. aureus in Africa

Improvement in cumulative response rates following implementation of a financial incentive

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