Collective librations of water molecules in the crystal lattice of rubidium bromide: experiment and simulation

Terahertz spectroscopy of RbBr reveals four prominent absorption lines at room temperature and a further 15 lines at 10 K. Via density-functional-theory (DFT) numerical modelling using the PBE0 hybrid GGA functional, all the absorptions are identified as correlated librations of water molecules in the RbBr lattice. Each libration mode is a combination of rocking, wagging and twisting motions of the water molecules. The number of libration lines and numerical modelling show that the C2v symmetry of water in RbBr is broken. Our modelling shows that the distribution of libration amplitudes and phases for different water molecules in the RbBr unit cell varies greatly between the different modes. All librational lines red-shift with increasing temperature. The rate of change for most lines is in the range 60–90 MHz K−1 (or (2–3) × 10−3 cm−1 K−1). Two lines shift more rapidly with temperature, at rates of 240 and 300 MHz K−1 (or (8 and 10) × 10−3 cm−1 K−1), respectively. Furthermore, the temperature dependence of the linewidth distinguishes two groups of lines. For one group, with weak linear temperature dependence of linewidth, cubic anharmonic terms in the RbBr crystal field are significant. This group is mainly associated with fully symmetric correlated librations. For the second group, with strong non-linear temperature dependence of the linewidth, quartic anharmonic terms in the RbBr crystal field are significant. However, the distribution of libration amplitudes, as well as the type of libration modes, influence the temperature dependence of the red shift, the linewidth, and the intensity, as well. Our combined experimental and theoretical investigation confirms the necessity of obtaining low-temperature data to observe all the calculated modes; moreover, the richness of detail in the temperature dependence of the data invites further modelling spanning a range of temperatures

Alcohol Intake and Blood Pressure: A Systematic Review Implementing a Mendelian Randomization Approach

Using a mendelian randomization approach Sarah Lewis and colleagues find strong support for the hypothesis that alcohol intake has a marked effect on blood pressure and the risk of hypertension

A study on wear evaluation of railway wheels based on multibody dynamics and wear computation

The wear evolution of railway wheels is a very important issue in railway engineering. In the past, the reprofiling intervals of railway vehicle steel wheels have been scheduled according to designers' experience. Today, more reliable and accurate tools in predicting wheel wear evolution and wheelset lifetime can be used in order to achieve economical and safety benefits. In this work, a computational tool that is able to predict the evolution of the wheel profiles for a given railway system, as a function of the distance run, is presented. The strategy adopted consists of using a commercial multibody software to study the railway dynamic problem and a purpose-built code for managing its pre- and post-processing data in order to compute the wear. The tool is applied here to realistic operation scenarios in order to assess the effect of some service conditions on the wheel wear progression

The Marine Nature of Nuwuk Lake and Small Ponds of the Peninsula of Point Barrow Alaska

Discusses a score or more ponds, some transient, some persistent, on this narrow gravel spit, their location, nature, salinity and temperature; their biotas, marine and fresh-water, are outlined. Nuwuk Lake, the largest water body of the locality, approx. 600 ft long, max. depth 18.5 ft, is treated in some detail: its bottom, its formation by converging currents of the Bering and Chukchi Seas, ice conditions, temperature, salinity and O2-content. The biotas: euryhaline, reduced shallow-sea fauna are dealt with and the organisms collected during 1952-1960 are tabulated. Comparison is made with the few halocline lakes known in northern Russia and Scandinavia, notably Mogil'noye on Kil'din Island

Towards a Standard Approach for Wear Testing of Wheel and Rail Materials

Examination of the literature for wear testing methodologies for wheel and rail material reveals that while only a few different techniques have been used there is a wide variety in exactly how the tests have been conducted and the resulting data reported. This makes comparison of the data very difficult. This work, carried out as part of the International Collaborative Research Initiative (ICRI) which is aiming to bring together wheel/rail interface researchers from across the world to collate data and knowledge to try to solve some of the common problems that are faced, has examined the different approaches used and attempted to pull together all the good practice used into a test specification for future twin disc testing for wheel and rail materials. Adoption of the method will allow data to be compared reliably and eventually enable data to be compiled into wear maps to use as input, for example, to multi-body dynamics simulation wear prediction tools

An evaluation of dexterity and cutaneous sensibility tests for use with medical gloves

© 2015 Institution of Mechanical Engineers.The ability of selected dexterity and cutaneous sensibility tests to measure the effect of medical glove properties (material, fit, and number of layers) on manual performance was analyzed. Manual performance testing of gloves to-date has focused on thicker gloves where the effects are more obvious. However, clinicians have reported dissatisfaction with some medical gloves and a perceived detriment to performance of new materials compared to latex. Three tests (Purdue Pegboard Test, Crawford Small Parts Dexterity Test, and Semmes-Weinstein Monofilaments) were performed by 18 subjects in five hand conditions (ungloved; best-fitting, loose-fitting and a double layer of latex examination gloves; best-fitting vinyl gloves). Tests were performed in the ungloved condition first, and the order of the gloved tests was randomized. Learning behavior was also measured. The Purdue test showed a significant effect of hand condition, but no differences between latex and vinyl. No significant effect of hand condition was found in the Crawford "Pins and Collars" test, but the "Screws" test showed promising discrimination between glove types. The Monofilaments test showed a significant effect of hand condition on cutaneous sensibility, particularly a reduction when "double-gloving," but no significant differences between glove types. Existing tests show some ability to measure the effect of gloves and their properties on manual performance but are not comprehensive and require further validation. In order to fully describe the effects of medical gloves on manual performance, further tests should be designed with greater resolution and that better replicate clinical manual tasks

Tribute to David Heaney

Peer reviewedPublisher PD

Le Travail de Proximité auprès des Usagers de Drogues en Europe : Concepts, pratiques et terminologie

Traduction française, déposée à l'OCDE, de : Outreach Worg Among Drug Users in Europe. Concepts, Practice and Terminology, EMCDDA, June 1999, Insights Series, 2Il s'agit d'un état des lieux du développement du travail de proximité dans chaque pays de l'Union Européenne. Ce travail s'appuie sur l'analyse de la littérature et sur une enquête faite en 1998 pour l'Observatoire Européen des Drogues et de la Toxicomanie. Sont abordés l'histoire du travail de proximité, sa définition, les questions de terminologie, les différentes formes de travail et les modèles d'intervention rencontrés, et enfin les objectifs et les méthodes du travail de proximité. Les points communs entre les pays et les divergences dans les choix et les pratiques ressortent de l'ensemble de ce tableau qui est une première approche de ce suje

Is there an association between PEPFAR funding and improvement in national health indicators in Africa? A retrospective study

BACKGROUND: The US President's Emergency Plan for AIDS Relief (PEPFAR) was reauthorized in June 2008 with a three-fold increase in funds, and a broader, more explicit mandate to improve health in the low- and middle-income countries that it funded. However, the ability of a disease-specific, or vertical, programme to have a spill-over effect and improve health outcomes has been questioned. In this study, we sought to examine associations between being designated as a PEPFAR focus country (and receiving increased PEPFAR funding) and non-HIV-specific health outcomes in the World Health Organization (WHO) Africa Region, the area most affected by the HIV/AIDS epidemic. METHODS: A retrospective analysis of publicly available health outcomes data published by the World Health Organization was performed for all countries in the WHO Africa Region. Fractional changes in health indicators between 2000 and 2006 were calculated, and PEPFAR focus and non-focus countries were then compared. RESULTS: Overall, countries in the WHO Africa Region showed a small worsening in health outcomes status when all indicators were analyzed together and weighted equally. However, more health indicators improved than worsened over this six-year period. A comparison of PEPFAR focus and non-focus countries found no significant difference in the fractional change among 13 of 14 health indicators during the study period. CONCLUSIONS: This study suggests that vertical programmes, even one that is the scale of PEPFAR, may have little or no impact on health outcomes not explicitly targeted