724 research outputs found

    Studies of the superconducting properties of Sn1-xInxTe (x=0.38 to 0.45) using muon-spin spectroscopy

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    The superconducting properties of Sn1-xInxTe (x = 0.38 to 0.45) have been studied using magnetization and muon-spin rotation or relaxation (muSR) measurements. These measurements show that the superconducting critical temperature Tc of Sn1-xInxTe increases with increasing x, reaching a maximum at around 4.8 K for x = 0.45. Zero-field muSR results indicate that time-reversal symmetry is preserved in this material. Transverse-field muon-spin rotation has been used to study the temperature dependence of the magnetic penetration depth lambda(T) in the mixed state. For all the compositions studied, lambda(T) can be well described using a single-gap s-wave BCS model. The magnetic penetration depth at zero temperature lambda(0) ranges from 500 to 580 nm. Both the superconducting gap Delta(0) at 0 K and the gap ratio Delta(0)/kBTc indicate that Sn1-xInxTe (x = 0.38 to 0.45) should be considered as a superconductor with intermediate to strong coupling.Comment: 7 pages, 6 figures, 3 table

    Observation of surface states on heavily indium doped SnTe(111), a superconducting topological crystalline insulator

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    The topological crystalline insulator tin telluride is known to host superconductivity when doped with indium (Sn1−x_{1-x}Inx_{x}Te), and for low indium contents (x=0.04x=0.04) it is known that the topological surface states are preserved. Here we present the growth, characterization and angle resolved photoemission spectroscopy analysis of samples with much heavier In doping (up to x≈0.4x\approx0.4), a regime where the superconducting temperature is increased nearly fourfold. We demonstrate that despite strong p-type doping, Dirac-like surface states persist

    Nanomaterials of the topological crystalline insulators, Pb1–xSnxTe and Pb1–xSnxSe

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    Topological insulators (TIs) and topological crystal insulators (TCIs) exhibit exotic surface properties. We present optimised growth procedures to obtain high quality bulk crystals of the TCIs Pb1-xSnxTe and Pb1-xSnxSe, and nanowires from the bulk crystals using the vapour-liquid-solid (VLS) technique. Nanowires of Pb1-xSnxTe have been produced with a Sn composition of x = 0.25, at which a transition from trivial to non-trivial insulator is reported. The results obtained on the growth of nanomaterials of Pb1-xSnxSe are also described. Detailed characterisation of the bulk crystals and the nanomaterials through x-ray diffraction, microscopy techniques and EDX analysis are presente

    Integrating improved goat breeds with new varieties of sweet potatoes and cassava in the agro-pastoral systems of Tanzania: A gendered analysis

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    This paper focuses on analysing gender issues in livestock and root crop production. Qualitative data for the study was collected through gender disaggregated group discussions (GDs) in two districts, Mvomero and Kongwa in Tanzania. Data were collected from 4 communities representing the four villages—Wami Luhindo and Kunke in Mvomero, and Masinyeti and Ihanda in Kongwa respectively. A total of 12 GDs were conducted involving 224 men and women who participated in the GDs. The qualitative data were analysed descriptively and by using measures such as percentages, tables, pie, bar charts and Venn diagrams. The study found that men owned all the goats and made all goat related decisions unilaterally. Women were by far less likely than men to own not only goats, but also livestock in general. On management of goats, an important set of differences in activities is associated with gender as well as with age. Changing livelihood opportunities such as rural–urban migration were identified as a factor that influenced gender and goat management and this increases workload for women. On decision-making over goats, women have limited control over decisions on sale and use of incomes generated from sale of goats. Ownership of crops between men and women is quite distinct, and depends on the market prices of crops and yield of the crop they grow for cash. Men own cash crops or crops for cash whereas women own subsistence or food crops for home consumption. Wealth status had a direct relation with individual decision-making on crops, rich men and women decided on what crops to cultivate, whereas non-rich farmers worked on wealthy farmers’ farms as casual labourers. Perceptions of women and men on the potential benefits of integrating root crops and goat varied. Men perceived value addition resulting from owning dairy goats and the attendant increase in income for them whereas women perceived change in status quo and increase workload resulting from stall goat management activities. Some participants explained that the anticipated increase in men’s real income could come about either through men accessing women’s income, or more commonly, women using their earnings to substitute men’s expenditure on household needs and children’s education. The study concluded that there are gender differences on perceived potential of integrating root crops and dairy goat production, as prevailing tradition may limit women’s participation. The beneficiaries expressed the timeliness of CGP project and exhibited willingness to partake in the project and ensure equitable benefits for participants if participatory gender training and awareness is ensured at both the household and community level. The study recommended that investing in rigorous gender trainings for both women and men, to initially sensitize them on the importance of including both women and men in development projects and sustain their continued understanding of the importance of gender inclusive activities

    Immunosuppressant Responsive Neuropsychiatric Systemic Lupus Erythematosus Manifestations Initially Diagnosed As Schizophrenia and Bipolar Disorder

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    Systemic lupus erythematosus (SLE) is a well-documented multi-system autoimmune disease with increased frequency noted in younger females and among minority populations. Disease-defining signs and symptoms can vary widely and involve multiple organ systems including the nervous system. Involvement of the nervous system, known as neuropsychiatric SLE (NPSLE) can present as manifestations consistent with central nervous system or peripheral nervous system pathologies, with the former including presentations of psychiatric illnesses. This case report reviews a 21-year-old Black female\u27s presentation that was most notable for psychosis with other findings on examination and laboratory investigation resulting in a diagnosis of NPSLE. Our patient had a positive initial response to high-dose steroids with improvement of her psychosis and was planned for further treatment with the well-known chemotherapy and immunomodulatory agent, cyclophosphamide

    Three dimensional simulation to observe the effects of the static magnetic field on the growth of Si0.25Ge0.75 in a vertical Bridgman setting

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    Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.A numerical modeling and simulation of single bulk crystals of Si0.25Ge0.75 growth with Si rich is conducted to investigate the effect of static magnetic field on the heat and mass transfer in the solvent region in a vertical Bridgman furnace. The curvature and shape of the silicon concentration in the process of crystallization near the growth interface are also examined. Different magnetic field intensities were applied. The meridianal flow as well as the azimuthal flow in the solvent region under the applied polynomial temperature along the vertical dimension of the model were investigated and it was found that the axial magnetic field does not have effective influence on the buoyancy induced convection in the solvent region.dc201
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