2,079 research outputs found

    Sida supported programme within the African Energy Policy Research Network (AFREPREN)

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    Do you eat Achu here? Nurturing as a way of life in a Cameroon diaspora

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    Earlier studies on migration were largely dominated by the study of the determinants of migration, with economic theories being at the fore in explaining this phenomenon. Our focus instead will be on the life-cultivating practices that migrants associate with ‘home societies’ and wish to maintain in host societies. Rather than pursue the darker side of ‘biopolitics’, we focus instead on the domestication of nurtured life and the privatization of everyday practices ensuring well-being within the diasporic setting of Grassfield Cameroonians in Cape Town

    SPLENIC HOMOTRANSPLANTATION.

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    During the past 12 months, five clinical whole-organ splenic homotransplantations have been carried out with the objective of providing active immunologic tissue for the recipient patients. In one case with hypogammaglobulinemia, it was hoped that the transplanted tissue would alleviate a state of immunologic deficiency. In the other four, all of whom had terminal malignancies, the purpose was to superimpose a state of altered immunologic reactivity upon the host in the hope of thereby suppressing the inexorable growth of the neoplasms. As will be described, these procedures can now be judged in each instance to have been without benefit. Nevertheless, full documentation of the cases seems justified not only because of the many implications of transplantation of immunologically competent tissue, but also because of the potentially important observations made during the care of these patients. In addition, a full account will be presented of the supporting canine studies of splenic homotransplantation, inasmuch as many of the principles of clinical therapy and investigation derived from prior observations in the dog. The fact that it is possible to obtain viable splenic homografts in the dog for as long as two-thirds of a year without the production of runt disease or other harmful effects may have application in future research on bone marrow, other lymphoid, or hepatic homografts

    A Self-Consistent Marginally Stable State for Parallel Ion Cyclotron Waves

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    We derive an equation whose solutions describe self-consistent states of marginal stability for a proton-electron plasma interacting with parallel-propagating ion cyclotron waves. Ion cyclotron waves propagating through this marginally stable plasma will neither grow nor damp. The dispersion relation of these waves, {\omega} (k), smoothly rises from the usual MHD behavior at small |k| to reach {\omega} = {\Omega}p as k \rightarrow \pm\infty. The proton distribution function has constant phase-space density along the characteristic resonant surfaces defined by this dispersion relation. Our equation contains a free function describing the variation of the proton phase-space density across these surfaces. Taking this free function to be a simple "box function", we obtain specific solutions of the marginally stable state for a range of proton parallel betas. The phase speeds of these waves are larger than those given by the cold plasma dispersion relation, and the characteristic surfaces are more sharply peaked in the v\bot direction. The threshold anisotropy for generation of ion cyclotron waves is also larger than that given by estimates which assume bi-Maxwellian proton distributions.Comment: in press in Physics of Plasma

    Improved Si:As BIBIB (Back-Illuminated Blocked-Impurity-Band) hybrid arrays

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    Results of a program to increase the short wavelength (less than 10 microns) detective quantum efficiency, eta/beta, of Si:As Impurity Band Conduction arrays are presented. The arrays are epitaxially grown Back-Illuminated Blocked (BIB) Impurity-Band (BIBIB) 10x50 detectors bonded to switched-FET multiplexers. It is shown that the 4.7 microns detective quantum efficiency increases proportionately with the thickness of the infrared active layer. A BIB array with a thick active layer, designed for low dark current, exhibits eta/beta = 7 to 9 percent at 4.7 microns for applied bias voltages between 3 and 5 V. The product of quantum efficiency and photoelectric gain, etaG, increases from 0.3 to 2.5 as the voltage increases from 3 to 5 V. Over this voltage range, the dark current increases from 8 to 120 e(-)s(-1) at a device temperature of 4.2 K and is under 70 e(-)s(-1) for all voltages at 2 K. Because of device gain, the effective dark current (equivalent photon rate) is less than 3 e(-)s(-1) under all operating conditions. The effective read noise (equivalent photon noise) is found to be less than 12 electrons under all operating conditions and for integration times between 0.05 and 100 seconds

    Macroscopic control parameter for avalanche models for bursty transport

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    Similarity analysis is used to identify the control parameter RA for the subset of avalanching systems that can exhibit self-organized criticality (SOC). This parameter expresses the ratio of driving to dissipation. The transition to SOC, when the number of excited degrees of freedom is maximal, is found to occur when RA-->0. This is in the opposite sense to (Kolmogorov) turbulence, thus identifying a deep distinction between turbulence and SOC and suggesting an observable property that could distinguish them. A corollary of this similarity analysis is that SOC phenomenology, that is, power law scaling of avalanches, can persist for finite RA with the same RA-->0 exponent if the system supports a sufficiently large range of lengthscales, necessary for SOC to be a candidate for physical (RA finite) systems

    On the effect of Ti on Oxidation Behaviour of a Polycrystalline Nickel-based Superalloy

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    Titanium is commonly added to nickel superalloys but has a well-documented detrimental effect on oxidation resistance. The present work constitutes the first atomistic-scale quantitative measurements of grain boundary and bulk compositions in the oxide scale of a current generation polycrystalline nickel superalloy performed through atom probe tomography. Titanium was found to be particularly detrimental to oxide scale growth through grain boundary diffusion

    Visualizing social acceptance research: A bibliometric review of the social acceptance literature for energy technology and fuels

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    The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.erss.2017.12.006. © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper conducts content and bibliometric analysis of 857 articles representing the knowledge domain for the social acceptance of energy technology and fuels. The objective is to identify basic trends and characteristics in the literature, identify current research fronts and pivotal papers therein, and map these fronts to their respective intellectual bases. We accomplish this by analyzing metadata, keyword use and citation networks within our dataset. We conclude with an evaluation of influence, structure, and collaboration and interdisciplinary dialogue in the field.Research made possible by the financial support of the Natural Sciences and Engineering Research Council of Canada (NSERC) as part of the NSERC Energy Storage Technology (NEST) Network
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