233 research outputs found

    Flex-PCB Pitch-Adapters for Silicon Micro-Strip Detectors

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    An Evaluation of Sustainability and Subsidy Dependence of Microfinance Institutions in Ghana

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    The research aims to explore the understanding of the relationship between sustainability of microfinance institutions (MFIs), subsidy dependence index (SDI) and operational self-sufficiency (OSS).The research study is based on initial exploratory study by analyzing data on 14 executive directors in qualitative interviews and 116 relationship executives in research questionnaires. The microfinance institutions identified were the Financial Non-Governmental Organizations (FNGOs), the Savings and Loans Companies (S&L), the Credit Unions (CUs), the Rural Banks (RBs) and the SUSU Companies. Multiple Regressions which allows for the testing of theories or models established a significant relationship between the Operational Self Sufficiency (OSS) and the predictors, especially the drop-out rate of clients and average loans. The Subsidy Dependence Index (SDI) was calculated for the various types of MFIs and the result was a high dependency ratio especially among the FNGOs. Though the dependency is on the decline, it is very slow indicating that most MFIs will depend on subsidies for a very long time to come. Key words: Subsidy dependence; Sustainability; Operational self-sufficiency; Viability; Microfinanc

    Success of Microfinance Institutions: The Ghanaian Experience

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    Success in microfinance refers to measures which when adopted will significantly improve the life and operations of the institutions though many authors have different views on what constitute success. The following imperatives have been used to scan success of microfinance institutions (MFIs): acquiring more clients, effective and efficient loan processing, effective record keeping, increased savings, external and internal audits, level of staff remuneration and staff turnover rate. The research was based on both qualitative and quantitative approaches. First, interviews were held with selected CEOs from all the categories of MFIs in Ghana. This was followed by self-administered survey involving 130 microfinance institutions. The results indicated that all the perceived factors were significant in determining the success of MFIs. Key words: Success; Microfinance; Sustainability; Remuneratio

    Effector and Central Memory Poly-Functional CD4+ and CD8+ T Cells are Boosted upon ZOSTAVAX® Vaccination

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    ZOSTAVAX® is a live attenuated varicella-zoster virus (VZV) vaccine that is licensed for the protection of individuals ≥ 50 years against shingles, and its most common complication, post-herpetic neuralgia. While IFN responses increase upon vaccination, the quality of the T cell response has not been elucidated. By using polychromatic flow cytometry, we characterized the breadth, magnitude, and quality of ex vivo CD4+ and CD8+ T cell responses induced 3 – 4 weeks after ZOSTAVAX vaccination of healthy adults. We show, for the first time that the highest frequencies of VZV-specific CD4+ T cells were poly-functional CD154+IFNγ+IL-2+TNFα+ cells, which were boosted upon vaccination. The CD4+ T cells were broadly reactive to several VZV proteins, with IE63 ranking the highest amongst them in the fold-rise of poly-functional cells, followed by IE62, gB, ORF9, and gE. We identified a novel poly-functional ORF9-specific CD8+ T cell population in 62% of the subjects, and these were boosted upon vaccination. Poly-functional CD4+ and CD8+ T cells produced significantly higher levels of IFNγ, IL-2, and TNFα compared to mono-functional cells. After vaccination, a boost in the expression of IFN by poly-functional IE63-and ORF9-specific CD4+ T cells, and IFNγ, IL-2, and TNFα by ORF9-specific poly-functional CD8+ T cells was observed. Responding poly-functional T cells exhibited both effector (CCR7−CD45RA−CD45RO+), and central (CCR7+CD45RA−CD45RO+) memory phenotypes, which expressed comparable levels of cytokines. Altogether, our studies demonstrate that a boost in memory poly-functional CD4+ T cells, and ORF9-specific CD8+ T cells may contribute towards ZOSTAVAX efficacy

    The reverse gyrase helicase-like domain is a nucleotide-dependent switch that is attenuated by the topoisomerase domain

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    Reverse gyrase is a topoisomerase that introduces positive supercoils into DNA in an ATP-dependent manner. It is unique to hyperthermophilic archaea and eubacteria, and has been proposed to protect their DNA from damage at high temperatures. Cooperation between its N-terminal helicase-like and the C-terminal topoisomerase domain is required for positive supercoiling, but the precise role of the helicase-like domain is currently unknown. Here, the characterization of the isolated helicase-like domain from Thermotoga maritima reverse gyrase is presented. We show that the helicase-like domain contains all determinants for nucleotide binding and ATP hydrolysis. Its intrinsic ATP hydrolysis is significantly stimulated by ssDNA, dsDNA and plasmid DNA. During the nucleotide cycle, the helicase-like domain switches between high- and low-affinity states for dsDNA, while its affinity for ssDNA in the ATP and ADP states is similar. In the context of reverse gyrase, the differences in DNA affinities of the nucleotide states are smaller, and the DNA-stimulated ATPase activity is strongly reduced. This inhibitory effect of the topoisomerase domain decelerates the progression of reverse gyrase through the nucleotide cycle, possibly providing optimal coordination of ATP hydrolysis with the complex reaction of DNA supercoiling

    Pre-breakup magmatism on the Vøring margin: Insight from new sub-basalt imaging and results from Ocean Drilling program hole 642E

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    Highlights • Sub-basalt imaging improvement on the Vøring Margin • Definition of a new seismic facies unit: the Lower Series Flows • Significant organic carbon content within the melting crustal segment • Apectodinium augustum marker for the PETM is reworked into the Lower Series Flows • The Lower Series Flows, early Eocene in age, predate the Vøring Margin breakup Abstract Improvements in sub-basalt imaging combined with petrological and geochemical observations from the Ocean Drilling Program (ODP) Hole 642E core provide new constraints on the initial breakup processes at the Vøring Margin. New and reprocessed high quality seismic data allow us to identify a new seismic facies unit which we define as the Lower Series Flows. This facies unit is seismically characterized by wavy to continuous subparallel reflections with an internal disrupted and hummocky shape. Drilled lithologies, which we correlate to this facies unit, have been interpreted as subaqueous flows extruding and intruding into wet sediments. Locally, the top boundary of this facies unit is defined as a negative in polarity reflection, and referred as the K-Reflection. This reflection can be correlated with the spatial extent of pyroclastic deposits, emplaced during transitional shallow marine to subaerial volcanic activities during the rift to drift transition. The drilled Lower Series Flows consist of peraluminous, cordierite bearing peperitic basaltic andesitic to dacitic flows interbedded with thick volcano-sedimentary deposits and intruded sills. The peraluminous geochemistry combined with available C (from calcite which fills vesicles and fractures), Sr, Nd, and Pb isotopes data point towards upper crustal rock-mantle magma interactions with a significant contribution of organic carbon rich pelagic sedimentary material during crustal anatexis. From biostratigraphic analyses, Apectodinium augustum was found in the The Lower Series Flows. This species is a marker for the Paleocene – Eocene Thermal Maximum (PETM). However, the absence of very low carbon isotope values (from bulk organic matter), that characterize the PETM, imply that A.augustum was reworked into the early Eocene sediments of this facies unit which predate the breakup time of the Vøring Margin. Finally, a plausible conceptual emplacement model for the Lower Series Flows facies unit is proposed. This model comprises several stages: (1) the emplacement of subaqueous peperitic basaltic andesitic flows intruding and/or extruding wet sediments; (2) a subaerial to shallow marine volcanism and extrusion of dacitic flows; (3) a proto-breakup phase with intense shallow marine to subaerial explosive volcanism responsible for pyroclastic flow deposits which can be correlated with the seismic K-Reflection and (4) the main breakup stage with intense transitional tholeiitic MORB-type volcanism and large subsidence concomitant with the buildup of the Seaward Dipping Reflector wedge

    Stochastic Dispersal Rather Than Deterministic Selection Explains the Spatio-Temporal Distribution of Soil Bacteria in a Temperate Grassland

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    Spatial and temporal processes shaping microbial communities are inseparably linked but rarely studied together. By Illumina 16S rRNA sequencing, we monitored soil bacteria in 360 stations on a 100 square meter plot distributed across six intra-annual samplings in a rarely managed, temperate grassland. Using a multi-tiered approach, we tested the extent to which stochastic or deterministic processes influenced the composition of local communities. A combination of phylogenetic turnover analysis and null modeling demonstrated that either homogenization by unlimited stochastic dispersal or scenarios, in which neither stochastic processes nor deterministic forces dominated, explained local assembly processes. Thus, the majority of all sampled communities (82%) was rather homogeneous with no significant changes in abundance-weighted composition. However, we detected strong and uniform taxonomic shifts within just nine samples in early summer. Thus, community snapshots sampled from single points in time or space do not necessarily reflect a representative community state. The potential for change despite the overall homogeneity was further demonstrated when the focus shifted to the rare biosphere. Rare OTU turnover, rather than nestedness, characterized abundance-independent β-diversity. Accordingly, boosted generalized additive models encompassing spatial, temporal and environmental variables revealed strong and highly diverse effects of space on OTU abundance, even within the same genus. This pure spatial effect increased with decreasing OTU abundance and frequency, whereas soil moisture – the most important environmental variable – had an opposite effect by impacting abundant OTUs more than the rare ones. These results indicate that – despite considerable oscillation in space and time – the abundant and resident OTUs provide a community backbone that supports much higher β-diversity of a dynamic rare biosphere. Our findings reveal complex interactions among space, time, and environmental filters within bacterial communities in a long-established temperate grassland

    Comportamento de dois genótipos de milho cultivados em sistema de aléias preestabelecido com diferentes leguminosas arbóreas.

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    O cultivo em aléias tem sido recomendado como alternativa para a substituição da agricultura de corte e queima, no trópico úmido, devido à grande capacidade de produção de matéria orgânica e de reciclagem de nutrientes, mas algumas dúvidas quanto à sustentabilidade e à competição interespecífica são persistentes. O objetivo no trabalho foi avaliar a viabilidade da cultura do milho em um sistema de cultivo em aléias de leguminosas arbóreas. O delineamento experimental utilizado foi em blocos casualisados, com quatro repetições dos tratamentos: aléias de sombreiro (Clitoria fairchildiana), ingá (Inga edulis), guandu (Cajanus cajan) e leucena (Leucaena leucocephala) e uma testemunha sem aléias. Foram avaliadas a remobilização de carbono e nitrogênio, massa de grãos, massa de mil grãos e competição interespecífica entre as cultivares de milho e as leguminosas. A produção de grãos foi maior nas parcelas com C. fairchildiana e L. leucocephala. A produtividade do híbrido de milho foi superior à da variedade em todos os tratamentos. A produtividade e a massa de mil grãos de milho não são negativamente afetadas pela distância da linha da leguminosa arbórea. Esse estudo conclui que o sistema de aléias com leguminosas arbóreas é uma alternativa importante ao manejo sustentável dos agroecossistemas no tropico úmido. Além disso, nessa região a produtividade em grãos na cultura do milho é favorecida no sistema de aléias preeestabelecidas com as leguminosas arbóreas sombreiro, ingá e leucena e pela utilização de genótipos eficientes no aproveitamento do nitrogênio, cujo sincronismo entre a liberação e a absorção do N aplicado por meio das leguminosas deve ser aprimorado

    Deviations from mean-field behavior in disordered nanoscale superconductor-normal-metal-superconductor arrays

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    We have fabricated quasi-two-dimensional arrays of nano-scale Pb grains coupled by an overlayer of Ag grains. Their temperature dependent resistive transitions follow predictions for an array of mesoscopic superconductor-normal-superconductor junctions. The decrease of their transition temperatures with Ag overlayer thickness systematically deviates from the Cooper limit theory of the proximity effect as the Pb grain size decreases. The deviations occur when the estimated number of Cooper pairs per grain is less than or equal to 1 and suggest the approach to a superconductor to metal transition.Comment: 11 pages, Pdf only, Revisions include text and figure
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