844 research outputs found

    Studies of hot B subdwarfs. Part 2: Energy distributions of three bright sdB/sdOB stars in the 950-5500 angstrom range

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    Voyager ultraviolet spectrometer observations of the subdwarf B or OB stars HD 205805, UV 1758+36 and Feige 66 are presented. All three objects display the H I Layman series in absorption. These observations are combined with low dispersion IUE spectrophotometry and with Stroemgren photometry to construct virtually complete energy distributions, which extend over the range 950-5500 angstroms. Effective temperatures based on model atmosphere calculations for high gravity, hydrogen rich stars are determined. Our analyses yield T Sub e 28,200 + or - 1300 K for HD 205805, T sub e 31, 800 + or - 1100 K for UV 1758+36, and T sub e 35,700 + or - 1500 K for Feige 66. The importance of far ultraviolet observations below L sub alpha in reducing the uncertainties associated with the interstellar extinction and the degradation of the IUE sensitivity is emphasized

    Exposure databases and exposure surveillance : promise and practice

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    Based on recent developments in occupational health and a review of industry practices, it is argued that integrated exposure database and surveillance systems hold considerable promise for improving workplace health and safety. A foundation from which to build practical and effective exposure surveillance systems is proposed based on the integration of recent developments in electronic exposure databases, the codification of exposure assessment practice, and the theory and practice of public health surveillance. The merging of parallel, but until now largely separate, efforts in these areas into exposure surveillance systems combines unique strengths from each subdiscipline. The promise of exposure database and surveillance systems, however, is yet to be realized. Exposure surveillance practices in general industry are reviewed based on the published literature as well as an Internet survey of three prominent industrial hygiene e-mail lists. Although the benefits of exposure surveillance are many, relatively few organizations use electronic exposure databases, and even fewer have active exposure surveillance systems. Implementation of exposure databases and surveillance systems can likely be improved by the development of systems that are more responsive to workplace or organizational-level needs. An overview of exposure database software packages provides guidance to readers considering the implementation of commercially available systems. Strategies for improving the implementation of exposure database and surveillance systems are outlined. A companion report in this issue on the development and pilot testing of a workplace-level exposure surveillance system concretely illustrates the application of the conceptual framework proposed

    SKELETAL KINEMATICS OF THE ANTERIOR CRUCIATE LIGAMENT DEFICIENT KNEE WITH AND WITHOUT FUNCTIONAL BRACES

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    Steinmann traction pins were implanted into the femur and tibia of six subjects having a partial or complete anterior cruciate ligament (ACL) rupture. Patients jumped for maximal horizontal distance and landed onto their deficient limb with the knee braced and unbraced. Tibiofemoral rotations and translations showed a general trend across subjects, i.e. skeletally based curves were similar in shape and amplitude. The tibia displaced anteriorly from footstrike to about peak vertical force onset (Fy). Thereafter the tibia moved posteriorly during flexion. Intra-subject kinematics was very repeatable but differences in anterior tibial translations were small between the brace conditions. This may be due to the invasiveness of this protocol, that landings were onto a deficient limb, or subjects jumped within their own comfort limits which did not maximally stress the ACL. Inter-subject differences were typically much larger

    Canada’s Earthquakes: ‘The Good, the Bad, and the Ugly’

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    Much of Canada is ‘earthquake country’. Tiny earthquakes (that can only be recorded by seismographs) happen every day. On average, earthquakes large enough to be felt occur every week in Canada, damaging earthquakes are years to decades apart, and some of the world’s largest earthquakes are typically separated by intervals of centuries. In this article, we provide details on the most significant earthquakes that have been recorded in, or near, Canada, including where and when they occurred, how they were felt, and the effects of those earthquakes. We also provide a brief review of how earthquakes are monitored across Canada and some recent earthquake hazard research. It is the results of this monitoring and research, which provide knowledge on earthquake hazard, that are incorporated into the National Building Code of Canada. This, in turn, will contribute to reduced property losses from future earthquakes across Canada. SOMMAIRE Un bonne partie du Canada est un ‘pays de sĂ©ismes’. De petits sĂ©ismes (que seuls les sĂ©ismographes peuvent enregistrer) s’y produisent quotidiennement. En moyenne, un sĂ©isme assez fort pour qu’on le ressente s’y produit Ă  intervalle d’une semaine; assez fort pour causer des dommages s’y produit Ă  intervalle de quelques annĂ©es Ă  quelques dĂ©cennies; alors que l’intervalle de rĂ©currence des plus grands sĂ©ismes est de l’ordre des siĂšcles. Dans le prĂ©sent article on trouvera des dĂ©tails sur les plus importants sĂ©ismes s’étant produits sur ou Ă  proximitĂ© du territoire canadien, incluant le lieu et le moment, leurs manifestations et leurs rĂ©percussions. On y dĂ©crit sommairement les moyens de dĂ©tection dĂ©ployĂ©s sur le territoire canadien ainsi que quelques-unes des recherches rĂ©centes sur les risques sismiques. Ce sont les rĂ©sultats des efforts de surveillance et des recherches sur les tremblements de terre qui ont Ă©tĂ© intĂ©grĂ©s dans le Code national du bĂątiment du Canada. Et cela aidera Ă  amoindrir les rĂ©percussions des sĂ©ismes Ă  venir sur la propriĂ©tĂ©

    A 10-hour period revealed in optical spectra of the highly variable WN8 Wolf-Rayet star WR 123

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    Aims. What is the origin of the large-amplitude variability in Wolf-Rayet WN8 stars in general and WR123 in particular? A dedicated spectroscopic campaign targets the ten-hour period previously found in the high-precision photometric data obtained by the MOST satellite. Methods. In June-August 2003 we obtained a series of high signal-to-noise, mid-resolution spectra from several sites in the {\lambda}{\lambda} 4000 - 6940 A^{\circ} domain. We also followed the star with occasional broadband (Johnson V) photometry. The acquired spectroscopy allowed a detailed study of spectral variability on timescales from \sim 5 minutes to months. Results. We find that all observed spectral lines of a given chemical element tend to show similar variations and that there is a good correlation between the lines of different elements, without any significant time delays, save the strong absorption components of the Hei lines, which tend to vary differently from the emission parts. We find a single sustained periodicity, P \sim 9.8 h, which is likely related to the relatively stable pulsations found in MOST photometry obtained one year later. In addition, seemingly stochastic, large-amplitude variations are also seen in all spectral lines on timescales of several hours to several days.Comment: 6 pages, 4 figures, 2 tables, data available on-line, accepted in A&A Research Note

    Target blood pressure for septic and vasodilatory shock: what is optimal?

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    Management of type 2 diabetes mellitus in people with severe mental illness: an online cross-sectional survey of healthcare professionals

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    Objectives To establish healthcare professionals’ (HCPs) views about clinical roles, and the barriers and enablers to delivery of diabetes care for people with severe mental illness (SMI). Design Cross-sectional, postal and online survey. Setting Trusts within the National Health Service (NHS), mental health and diabetes charities and professional bodies. Participants HCPs who care for people with type 2 diabetes mellitus (T2DM) and/or SMI in the UK. Primary and secondary outcome measures The barriers, enablers and experiences of delivering T2DM care for people with SMI, informed by the Theoretical Domains Framework (TDF). Results Responders were 273 HCPs, primarily mental health nurses (33.7%) and psychiatrists (32.2%). Only 25% of respondents had received training in managing T2DM in people with SMI. Mental health professionals felt responsible for significantly fewer recommended diabetes care standards than physical health professionals (p<0.001). For those seeing diabetes care as part of their role, the significant barriers to its delivery in the regression analyses were a lack of knowledge (p=0.003); a need for training in communication and negotiation skills (p=0.04); a lack of optimism about the health of their clients (p=0.04) and their ability to manage T2DM in people with SMI (p=0.003); the threat of being disciplined (p=0.02); fear of working with people with a mental health condition (p=0.01); a lack of service user engagement(p=0.006) and a need for incentives (p=0.04). The significant enablers were an understanding of the need to tailor treatments (p=0.04) and goals (p=0.02) for people with SMI. Conclusions This survey indicates that despite current guidelines, diabetes care in mental health settings remains peripheral. Even when diabetes care is perceived as part of a HCP’s role, various individual and organisational barriers to delivering recommended T2DM care standards to people with SMI are experienced

    Graph Theory and simple Hueckel Theory applied to benzene

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    We compare the results of application of graph theory and of simple Hueckel theory in its traditional form to benzene, as an instance of a conjugated molecular system. The identity of the results of solution of eigenvalues of the vertex adjacency matrix and characteristic values of the Hueckel determinant prove the isomorphism of these two formalisms. Because of the gross deficiencies of the Hueckel theory, we advocate its elimination from the teaching of chemistry in favour of graph theory that has many applications to molecular topology.Se compararon los resultados de la aplicación de la teoría de gråficos y de la teoría de Hueckel tradicional a benceno, como ejemplo de un sistema molecular conjugado. Los resultados idénticos entre los eigenvalores de la matriz de adyacencia de los vértices y los valores característicos del determinante de Hueckel verifican el isomorfismo de los dos formalismos. Se recomienda la eliminación de la teoría de Hueckel por sus deficiencias y en su lugar utilizar la teoría de gråficos que tiene muchas aplicaciones en topología molecular
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