7,932 research outputs found

    Defect chemistry and characterization Hg(1-x)Cd(x)Te

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    Iodine doped single crystal samples of mercury cadmium telluride were annealed at temperatures varying from 450 C to 600 C in Hg vapor and quenched to room temperature. Hall effect measurements at 77 K on the crystals cooled to room temperature indicate the samples to be n-type after anneals at high Hg pressures whereas they turn p-type after anneals at low Hg pressures; the electron concentration increases with increase in Hg pressure. The results are explained on the basis that the crystals are saturated with (Hg,Cd)I2, with a fraction of the iodine being present as donor occupying tellurium lattice sites and a fraction being present as acceptors resulting from the iodine on tellurium lattice sites pairing with the doubly ionized native acceptor defects. The solubility of the donor species increases with increase in Hg pressure, whereas that of the acceptor species increases with decrease in Hg pressure. Equilibrium constants for the incorporation of the iodine species as well as the pairing reaction were established

    Seasonal and socio-economic variations in clinical and self-reported malaria in Accra, Ghana: Evidence from facility data and a community survey

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    Objectives: This study characterizes the variations in malaria morbidity for Accra.Methods: Both routine reporting of presumptive, clinically diagnosed malaria in out-patient clinics and results from a longitudinal household survey are used in the analysis. In the household survey, cases of suspected malaria were self-reported by patients, based on diagnoses from health centers, hospitals, pharmacies, chemical sellers or traditional healers.Results: Although the malaria ascertainment is not based on parasitology, we see systematic and plausible patterns by season and by district associated with variations in rainfall by month and year. There are significant differences in malaria incidence by socioeconomic group, possibly linked with place, work or residence.Conclusions: Understanding these seasonal and geographic patterns have implications for both prevention and treatment of malaria-like morbidity in both children and adults in urban settings

    A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)

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    We present the results of a Nobeyama 45-m water maser and ammonia survey of all 94 northern GLIMPSE Extended Green Objects (EGOs), a sample of massive young stellar objects (MYSOs) identified based on their extended 4.5 micron emission. We observed the ammonia (1,1), (2,2), and (3,3) inversion lines, and detect emission towards 97%, 63%, and 46% of our sample, respectively (median rms ~50 mK). The water maser detection rate is 68% (median rms ~0.11 Jy). The derived water maser and clump-scale gas properties are consistent with the identification of EGOs as young MYSOs. To explore the degree of variation among EGOs, we analyze subsamples defined based on MIR properties or maser associations. Water masers and warm dense gas, as indicated by emission in the higher-excitation ammonia transitions, are most frequently detected towards EGOs also associated with both Class I and II methanol masers. 95% (81%) of such EGOs are detected in water (ammonia(3,3)), compared to only 33% (7%) of EGOs without either methanol maser type. As populations, EGOs associated with Class I and/or II methanol masers have significantly higher ammonia linewidths, column densities, and kinetic temperatures than EGOs undetected in methanol maser surveys. However, we find no evidence for statistically significant differences in water maser properties (such as maser luminosity) among any EGO subsamples. Combining our data with the 1.1 mm continuum Bolocam Galactic Plane Survey, we find no correlation between isotropic water maser luminosity and clump number density. Water maser luminosity is weakly correlated with clump (gas) temperature and clump mass.Comment: Astrophysical Journal, accepted. Emulateapj, 24 pages including 24 figures, plus 9 tables (including full content of online-only tables

    Living with hate relationships: familiar encounters, enduring racisms and geographies of entrapment

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    This paper utilises the concept of ‘hate relationships’ in conversation with the literature on geographies of encounter to explore experiences of racism for those entrapped by racist encounters with those who are familiar. In so doing we attend to the uneven and harmful risks involved in some forms of everyday urban encounter. We draw upon case notes collated by a hate advocacy service in North East England, UK, to illustrate the cumulative damaging force of enduring hate relationships. By drawing parallels with work on domestic violence, we suggest hate relationships evident in our data exhibit distinct temporalities of routinisation, whereby harmful ‘low level’ violence, often under the radar of the criminal justice system, gains force through repeated neighbourhood-based encounters. In so doing we also highlight both the situated and relational spatialities at work; localised encounters marked by familiarity, racialised territoriality and experiences of fear and immobility, but also relations of entrenched disadvantage and institutional failures that sustain harm. Concerted acts of resistance look to confront and/or escape these relationships, but as forms of resolution, where additional burdens are placed on victim/survivors, these are constrained by the same violent conditions through which such relationships are allowed to take shape

    Improving Dynamic Decision Making Through Training and Self-Reflection

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    The modern business environment requires managers to make effective decisions in a dynamic and uncertain world. How can such dynamic decision making (DDM) improve? The current study investigated the effects of brief training aimed at improving DDM skills in a virtual DDM task. The training addressed the DDM process, stressed the importance of self-reflection in DDM, and provided 3 self-reflective questions to guide participants during the task. Additionally, we explored whether participants low or high in self-reflection would perform better in the task and whether participants low or high in self-reflection would benefit more from the training. The study also explored possible strategic differences between participants related to training and self-reflection. Participants were 68 graduate business students. They individually managed a computer-simulated chocolate production company called CHOCO FINE and answered surveys to assess self-reflection and demographics. Training in DDM led to better performance, including the ability to solve initial problems more successfully and to make appropriate adjustments to market changes. Participants’ self-reflection scores also predicted performance in this virtual business company. High self-reflection was also related to more consistency in planning and decision making. Participants low in self-reflection benefited the most from training. Organizations could use DDM training to establish and promote a culture that values self-reflective decision making
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