2,605 research outputs found

    “Children For Death”

    Get PDF
    This article focuses on the changing cultural values of the matrilineage as kinsmen are integrated within the emerging conditions of economic transition in the early decades of British colonial domination and capitalist expansion in the Asante zone of the Gold Coast. Conditions of the modernities of colonialism, especially the rise of capitalist enterprises with its cash economies and consumption of European goods, bring about increasing tensions within the lineage as the allotment of wealth became unevenly distributed among kinsmen. Money symbolized new kinds of power, a power which was both occult and materialist in nature and which was associated with the nefarious deeds of witches. Witches, in turn, were consistently destructive within the realms of kinship and within other social relations, and were capable of committing the worst atrocities within Asante cosmology. Witchcraft maintained a physical presence in its abilities to bring about sickness, a material capacity to generate sudden levels of income, and a social tendency to ruin relations among kin. The destructive powers of witchcraft were subject to domination by the medicinal remedies and ritual performances of witch-catching shrines and the healer priests who owned and operated them. The numbers of such shrines greatly proliferated within Asante between 1906 and 1940. The article is based on fieldwork undertaken in 1994, 1995, 1997 in Kumase and within the National Archvies of Ghana in Accra, Cape Coast and Kumase.L’article étudie le changement des valeurs culturelles du matrilignage lié à l’insertion des membres de la parentèle dans les nouvelles conditions économiques qui marquent les premières décennies de la domination coloniale britannique et de l’expansion capitaliste dans le pays asante de Gold Coast. Les nouvelles caractéristiques introduites par le colonialisme, notamment l’essor des entreprises capitalistes et de l’économie marchande ainsi que la consommation de produits européens, provoquèrent des tensions accrues en raison de la redistribution inégale de la richesse au sein du lignage. La monnaie en vint à symboliser une nouvelle sorte de pouvoir, pouvoir à la fois matériel et occulte et associé à l’action maléfique des sorciers. Ces sorciers, à leur tour, exerçaient leur talent destructeur au sein de la parenté et des relations sociales en général et étaient, de surcroît, capables de commettre les pires atrocités dans le cadre de la cosmologie asante. Les pouvoirs destructeurs de la sorcellerie pouvaient être contrecarrés par les plantes médicinales et les rituels anti-sorciers accomplis dans les sanctuaires par les guérisseurs. Le nombre de ces sanctuaires s’est grandement accru en pays asante entre 1906 et 1940

    GaAs solar cells for laser power beaming

    Get PDF
    Efforts to develop GaAs solar cells for coupling to laser beams in the wavelength range of 800 to 840 nm are described. This work was motivated primarily by interests in space-tp-space power beaming applications. In particular, the Battelle Pacific Northwest Laboratories is conducting studies of the utilization of power beaming for several future space missions. Modeling calculations of GaAs cell performance were carried out using PC-1D to determine an appropriate design for a p/n cell structure. Epitaxial wafers were grown by MOCVD and cells fabricated at WSU Tri-Cities. Under simulated conditions, an efficiency of 53 percent was achieved for a cell coupled to 806 nm light at 400 mW/sq cm

    Epidemiology of bloodstream infections in a multicenter retrospective cohort of liver transplant recipients

    Get PDF
    Although some studies have examined the epidemiology of bloodstream infections after liver transplantation, they were based in single centers and did not identify bloodstream infections treated in other hospitals. METHODS: We retrospectively examined a cohort of 7912 adult liver transplant recipients from 24 transplant centers using 2004 to 2012 International Classification of Diseases, Ninth Revision, Clinical Modification billing data from 3 State Inpatient Databases, and identified bloodstream infections, inpatient death, and cumulative 1-year hospital costs. Multilevel Cox regression analyses were used to determine factors associated with bloodstream infections and death. RESULTS: Bloodstream infections were identified in 29% (n = 2326) of liver transplant recipients, with a range of 19% to 40% across transplant centers. Only 63% of bloodstream infections occurring more than 100 days posttransplant were identified at the original transplant center. Bloodstream infections were associated with posttransplant laparotomy (adjusted hazard ratio [aHR], 1.52), prior liver transplant (aHR, 1.42), increasing age (aHR, 1.07/decade), and some comorbidities. Death was associated with bloodstream infections with and without septic shock (aHR, 10.96 and 3.71, respectively), transplant failure or rejection (aHR, 1.41), posttransplant laparotomy (aHR, 1.40), prior solid-organ transplant (aHR, 1.48), increasing age (aHR, 1.15/decade), and hepatitis C cirrhosis (aHR, 1.20). The risk of bloodstream infections and death varied across transplant centers. Median 1-year cumulative hospital costs were higher for patients who developed bloodstream infections within 1 year of transplant compared with patients who were bloodstream infection-free (US 229806vsUS229 806 vs US 111 313; P < 0.001). CONCLUSIONS: Bloodstream infections are common and costly complications after liver transplantation that are associated with a markedly increased risk of death. The incidence and risk of developing bloodstream infections may vary across transplant centers

    Investigation of ZnSe-coated silicon substrates for GaAs solar cells

    Get PDF
    Studies are being carried out to determine the feasibility of using ZnSe as a buffer layer for GaAs solar cells grown on silicon. This study was motivated by reports in the literature indicating ZnSe films had been grown by metallorganic chemical vapor deposition (MOCVD) onto silicon with EPD values of 2 x 10(exp 5) cm(sup -2), even though the lattice mismatch between silicon and ZnSe is 4.16 percent. These results combined with the fact that ZnSe and GaAs are lattice matched to within 0.24 percent suggest that the prospects for growing high efficiency GaAs solar cells onto ZnSe-coated silicon are very good. Work to date has emphasized development of procedures for MOCVD growth of (100) ZnSe onto (100) silicon wafers, and subsequent growth of GaAs films on ZnSe/Si substrates. In order to grow high quality single crystal GaAs with a (100) orientation, which is desirable for solar cells, one must grow single crystal (100) ZnSe onto silicon substrates. A process for growth of (100) ZnSe was developed involving a two-step growth procedure at 450 C. Single crystal, (100) GaAs films were grown onto the (100) ZnSe/Si substrates at 610 C that are adherent and specular. Minority carrier diffusion lengths for the GaAs films grown on ZnSe/Si substrates were determined from photoresponse properties of Al/GaAs Schottky barriers. Diffusion lengths for n-type GaAs films are currently on the order of 0.3 microns compared to 2.0 microns for films grown simultaneously by homoepitaxy

    A Push-Button Molecular Switch

    Get PDF
    The preparation, characterization, and switching mechanism of a unique single-station mechanically switchable hetero[2]catenane are reported. The facile synthesis utilizing a “threading-followed-by-clipping” protocol features Cu^(2+)-catalyzed Eglinton coupling as a mild and efficient route to the tetrathiafulvalene-based catenane in high yield. The resulting mechanically interlocked molecule operates as a perfect molecular switch, most readily described as a “push-button” switch, whereby two discrete and fully occupied translational states are toggled electrochemically at incredibly high rates. This mechanical switching was probed using a wide variety of experimental techniques as well as quantum-mechanical investigations. The fundamental distinctions between this single-station [2]catenane and other more traditional bi- and multistation molecular switches are significant

    The Lag Model Applied to High Speed Flows

    Get PDF
    The Lag model has shown great promise in prediction of low speed and transonic separations. The predictions of the model, along with other models (Spalart-Allmaras and Menter SST) are assessed for various high speed flowfields. In addition to skin friction and separation predictions, the prediction of heat transfer are compared among these models, and some fundamental building block flowfields, are investigated

    Morally Respectful Listening and its Epistemic Consequences

    Get PDF
    What does it mean to listen to someone respectfully, that is, insofar as they are due recognition respect? This paper addresses that question and gives the following answer: it is to listen in such a way that you are open to being surprised. A specific interpretation of this openness to surprise is then defended

    Lessons on Marine Protected Area Management in Northern Boreal Regions from the United States and Norway

    Get PDF
    In comparison to tropical reef systems, relatively few marine protected areas (MPA’s) exist in temperate or subarctic systems (e.g., North Pacific and North Atlantic) where species diversity is lower, abundance of individual species is often higher, and many fish species exhibit large amounts of movement during one or more of their life stages, especially as adults. A review of MPA’s in three northern areas—the Northwest Atlantic, Northeast Atlantic, and the Northeast Pacific—indicates that MPA’s can be useful management tools towards fisheries management and habitat conservation. However, achieving fishery goals, such as sustainable use of the fisheries resources, will depend on population abundance (relative to unfished conditions) and fish behavior and movement. For example, depleted populations of stationary species such as Atlantic sea scallops, Placopecten magellanicus, in the Northeast Atlantic and European lobster, Homarus grammarus, in the North Sea have responded positively to small MPA’s, whereas migratory offshore Atlantic cod, Gadus morhua, and Pacific cod, Gadus macrocephalus, apparently do not appear to benefit from closed areas because of movement into fished areas. Efficient habitat conservation requires detailed habitat mapping on relevant spatial scales. In northern boreal systems with large remote areas, this information is difficult and expensive to access. An alternative strategy of closing and protecting unexploited areas has worked well for the Aleutian Island coral closure area in Alaska. MPA’s can be effective fisheries management tools when the species to be protected have been depleted and show a small to moderate level of movement, and reproductive success is ensured. MPA’s can be effective at preserving habitat when the design is based on scientific information and takes into account the impact on the user groups.publishedVersio

    Characterization of edge damage induced on REBCO superconducting tape by mechanical slitting

    Get PDF
    Rare-earth barium-copper-oxide (REBCO) superconductors are high-field superconductors fabricated in a tape geometry that can be utilized in magnet applications well in excess of 20 T. Due to the multilayer architecture of the tape, delamination is one cause of mechanical failure in REBCO tapes. During a mechanical slitting step in the manufacturing process, edge cracks can be introduced into the tape. These cracks are thought to be potential initiation sites for crack propagation in the tapes when subjected to stresses in the fabrication and operation of magnet systems. We sought to understand which layers were the mechanically weakest by locating the crack initiation layer and identifying the geometrical conditions of the slitter that promoted or suppressed crack formation. The described cracking was investigated by selectively etching and characterizing each layer with scanning electron microscopy, laser confocal microscopy, and digital image analysis. Our analysis showed that the average crack lengths in the REBCO, LaMnO3 (LMO) and Al2O3 layers were 34 μm, 28 μm, and 15 μm, respectively. The total number of cracks measured in 30mmof wire length was between 3000 and 5700 depending on the layer and their crack densities were 102 cracks mm-1 for REBCO, 108 cracks mm-1 for LMO, and 183 cracks mm-1 for Al2O3. These results indicated that there are separate crack initiation mechanisms for the REBCO and the LMO layers, as detailed in the paper. With a better understanding of the crack growth behavior exhibited by REBCO tapes, the fabrication process can be improved to provide a more mechanically stable and cost-effective superconductor

    A pilot randomized controlled trial to promote healthful fish consumption during pregnancy: The Food for Thought Study

    Get PDF
    Background: Nutritionists advise pregnant women to eat fish to obtain adequate docosahexaenoic acid (DHA), an essential nutrient important for optimal brain development. However, concern exists that this advice will lead to excess intake of methylmercury, a developmental neurotoxicant. Objective: Conduct a pilot intervention to increase consumption of high-DHA, low-mercury fish in pregnancy. Methods: In April-October 2010 we recruited 61 women in the greater Boston, MA area at 12–22 weeks gestation who consumed = 200mg/d of DHA from fish, compared with 33% in the Advice arm (p=0.005) and 53% in the Advice+GC arm (p=0.0002). We did not detect any differences in mercury intake or in biomarker levels of mercury and DHA between groups. Conclusions: An educational intervention increased consumption of fish and DHA but not mercury. Future studies are needed to determine intervention effects on pregnancy and childhood health outcomes. Trial registration Registered on clinicaltrials.gov as NCT0112676
    corecore