2,380 research outputs found

    Gerrymandering and Compactness: Implementation Flexibility and Abuse

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    The shape of an electoral district may suggest whether it was drawn with political motivations, or gerrymandered. For this reason, quantifying the shape of districts, in particular their compactness, is a key task in politics and civil rights. A growing body of literature suggests and analyzes compactness measures mathematically, but little consideration has been given to how these scores should be calculated in practice. Here, we consider the effects of a number of decisions that must be made in interpreting and implementing a set of popular compactness scores. We show that the choices made in quantifying compactness may themselves become political tools, with seemingly innocuous decisions leading to disparate scores. We show that when the full range of implementation flexibility is used, it can be abused to make clearly gerrymandered districts appear quantitatively reasonable. This complicates using compactness as a legislative or judicial standard to counteract unfair redistricting practices. This paper accompanies the release of packages in C++, Python, and R which correctly, efficiently, and reproducibly calculate a variety of compactness scores.Comment: 10 pages, 17 figures, 1 tabl

    Competing in the global economy: the competitiveness of the South African automotive components industry

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    Optimized up-down asymmetry to drive fast intrinsic rotation in tokamaks

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    Breaking the up-down symmetry of the tokamak poloidal cross-section can significantly increase the spontaneous rotation due to turbulent momentum transport. In this work, we optimize the shape of flux surfaces with both tilted elongation and tilted triangularity in order to maximize this drive of intrinsic rotation. Nonlinear gyrokinetic simulations demonstrate that adding optimally-tilted triangularity can double the momentum transport of a tilted elliptical shape. This work indicates that tilting the elongation and triangularity in an ITER-like device can reduce the energy transport and drive intrinsic rotation with an Alfv\'{e}n Mach number on the order of 1%1\%. This rotation is four times larger than the rotation expected in ITER and is sufficient to stabilize MHD instabilities. It is shown that this optimal shape can be created using the shaping coils of several experiments.Comment: 16 pages, 5 figure

    A Combined Limit on the Neutrino Mass from Neutrinoless Double-Beta Decay and Constraints on Sterile Majorana Neutrinos

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    We present a framework to combine data from the latest neutrinoless double-beta decay experiments for multiple isotopes and derive a limit on the effective neutrino mass using the experimental energy distributions. The combined limits on the effective mass range between 130-310 meV, where the spread is due to different model calculations of nuclear matrix elements (NMEs). The statistical consistency (p values) between this result and the signal observation claimed by the Heidelberg-Moscow experiment is derived. The limits on the effective mass are also evaluated in a (3+1) sterile neutrino model, assuming all neutrinos are Majorana particles.Comment: 8 pages, 8 figures. Version accepted by Phys Rev D, including latest CUORE-0 result

    The Durban auto cluster: Global competititon, collective efficiency and local development

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    Differences in the Presentation of Anorexia Nervosa between Males and Females

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    Anorexia nervosa (AN) is a serious psychiatric illness with an estimated lifetime prevalence of 0.3% in males and 0.9% in females. AN has the highest mortality rate of any psychiatric disorder—10-12 times greater than the general population, and approximately 20% of those with AN commit suicide. Unfortunately, most studies related to AN and other eating disorders (ED’s) have focused on females, leaving a relative scarcity of literature related to the presentation of AN among males. A complete understanding of AN’s signs and symptoms in both males and females is required for reliable detection in all individuals, as diagnostic bias favoring typical presentations of AN among females may contribute to under-detection, late detection, or improper treatment for males with AN. This review summarizes the state of the literature on differences in the presentation of AN between males and females in order to improve detection of AN in all individuals as well as guide future research investigating the efficacy and appropriateness of treatment methods in both females and males.Master of Public Healt
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