1,333 research outputs found

    Fixing All Moduli in a Simple F-Theory Compactification

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    We discuss a simple example of an F-theory compactification on a Calabi-Yau fourfold where background fluxes, together with nonperturbative effects from Euclidean D3 instantons and gauge dynamics on D7 branes, allow us to fix all closed and open string moduli. We explicitly check that the known higher order corrections to the potential, which we neglect in our leading approximation, only shift the results by a small amount. In our exploration of the model, we encounter interesting new phenomena, including examples of transitions where D7 branes absorb O3 planes, while changing topology to preserve the net D3 charge.Comment: 68 pages, 19 figures; v2: references adde

    An Automated Design-flow for FPGA-based Sequential Simulation

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    In this paper we describe the automated design flow that will transform and map a given homogeneous or heterogeneous hardware design into an FPGA that performs a cycle accurate simulation. The flow replaces the required manually performed transformation and can be embedded in existing standard synthesis flows. Compared to the earlier manually translated designs, this automated flow resulted in a reduced number of FPGA hardware resources and higher simulation frequencies. The implementation of the complete design flow is work in progress.\u

    A report on visits of fake clients, pretending to be in need of emergency contraception, to health facilities in Bulawayo, Zimbabwe

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    To identify bottlenecks in the delivery of comprehensive reproductive health care in Bulawayo, Zimbabwe's second city, a study was performed utilising volunteers pretending to be in need of emergency contraception. A total of 55 private, Zimbabwe National Family Planning Council, municipal and government health facilities were visited. These consultations resulted in 9 (16%) correct, 1 possiblycorrect and 15 wrong prescriptions for the morning-after pill (MAP); no treatment was prescribed in 30 instances. Public sector health personnel were very judgemental in their attitude toward sexually active teenagers. Although the Essential Drug List of Zimbabwe is quite clear about the MAP, many health providers are not aware of this, and others do not even have/use this book

    Effective Crack-Propagation Resistance Under Monotonic And Cyclic Loading

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    Crack propagation under monotonic and cyclic loading was investigated in alumina-epoxy composite specimens, produced via a multi-step infiltration technique. Under monotonic loading, an increase in effective fracture toughness was observed, which was attributed to the development of a bridging zone behind the crack-tip. A similar increase in crack propagation resistance was observed under cyclic loading, though this was more difficult to quantify. This was achieved approximately using an adjustment based on the Paris-law relation. This adjustment approach is described in this paper, and is also applied to fatigue results for graded composite specimens, in which the increase in crack-growth resistance with crack-extension is accompanied by a spatial variation in intrinsic and extrinsic crack-growth resistance
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