Fast Scalable Construction of (Minimal Perfect Hash) Functions

Recent advances in random linear systems on finite fields have paved the way for the construction of constant-time data structures representing static functions and minimal perfect hash functions using less space with respect to existing techniques. The main obstruction for any practical application of these results is the cubic-time Gaussian elimination required to solve these linear systems: despite they can be made very small, the computation is still too slow to be feasible. In this paper we describe in detail a number of heuristics and programming techniques to speed up the resolution of these systems by several orders of magnitude, making the overall construction competitive with the standard and widely used MWHC technique, which is based on hypergraph peeling. In particular, we introduce broadword programming techniques for fast equation manipulation and a lazy Gaussian elimination algorithm. We also describe a number of technical improvements to the data structure which further reduce space usage and improve lookup speed. Our implementation of these techniques yields a minimal perfect hash function data structure occupying 2.24 bits per element, compared to 2.68 for MWHC-based ones, and a static function data structure which reduces the multiplicative overhead from 1.23 to 1.03

GHZ-type and W-type entangled coherent states: generation and Bell-type inequality tests without photon counting

We study GHZ-type and W-type three-mode entangled coherent states. Both the types of entangled coherent states violate Mermin's version of the Bell inequality with threshold photon detection (i.e., without photon counting). Such an experiment can be performed using linear optics elements and threshold detectors with significant Bell violations for GHZ-type entangled coherent states. However, to demonstrate Bell-type inequality violations for W-type entangled coherent states, additional nonlinear interactions are needed. We also propose an optical scheme to generate W-type entangled coherent states in free-traveling optical fields. The required resources for the generation are a single-photon source, a coherent state source, beam splitters, phase shifters, photodetectors, and Kerr nonlinearities. Our scheme does not necessarily require strong Kerr nonlinear interactions, i.e., weak nonlinearities can be used for the generation of the W-type entangled coherent states. Furthermore, it is also robust against inefficiencies of the single-photon source and the photon detectors.Comment: 8 pages, 5 figures, to be published in Phys. Rev.

Black Hole Entropy and the Dimensional Continuation of the Gauss-Bonnet Theorem

The Euclidean black hole has topology $\Re^2 \times {\cal S}^{d-2}$. It is shown that -in Einstein's theory- the deficit angle of a cusp at any point in $\Re^2$ and the area of the ${\cal S}^{d-2}$ are canonical conjugates. The black hole entropy emerges as the Euler class of a small disk centered at the horizon multiplied by the area of the ${\cal S}^{d-2}$ there.These results are obtained through dimensional continuation of the Gauss-Bonnet theorem. The extension to the most general action yielding second order field equations for the metric in any spacetime dimension is given.Comment: 7 pages, RevTe

Cholera: A comparison of the 2008-9 and 2010 Outbreaks in Kadoma City, Zimbabwe

Introduction: Kadoma City experienced cholera outbreaks in 2008-9, and 2010, affecting 6,393 and 123 people, respectively. A study wasconducted to compare epidemiology of the cholera outbreaks. Methods: a descriptive cross sectional study was conducted, analyzing line list data for the 2 outbreaks. Proportions, means were generated and compared using the Chi Square test at 5% level of significance.Results: cholera cases were similar by gender and age, with the 20-30 years group being most affected. Rimuka township contributed 80% and 100% of city cases in 2008-9 and 2010, respectively, p value=0.000. In 2008-9, 91% of cholera cases presented within 2 days compared to 98% in 2010. Delay seeking treatment increased from 58% to 73% (p  value=0.001), with gender, and place equally affected. The 2010 outbreak evolved faster, resulting in higher proportion being managed in CTU. CFR was 2% in 2008-9, and 3.3% in 2010 (p value =0.31). Conclusion: the 2008-9 and 2010 cholera outbreaks were similar by age and gender.  Rimuka Township was most affected by the outbreaks. There was  worsening of delay seeking treatment. The 2010 outbreak was more rapid, leading to early opening of CTC. CFR was consistently above 1%

Discrimination against Mixed-Status Families and its Health Impact on Latino Children

Background and Objective: Restrictive immigration policies and discrimination are associated with negative health outcomes for immigrant and Latino families. Mixed-status families represent a unique subpopulation of Latinos affected by restrictive immigration policies. This qualitative study explored discrimination against mixed-status families and its potential health impact on Latino children from the perspective of Latina mothers. Methods: In 2017, twenty in-depth interviews with Latina mothers of mixed-status families living in northwestern North Carolina were conducted, transcribed, and analyzed. Constant comparison, an approach to grounded theory development, was used. Results: Nine themes emerged that reflected experiences with discrimination and its negative impact on children. Themes included more frequent and severe discrimination during and after the 2016 US presidential election, determination to stay together and remain in the US, experiences of discrimination in multiple settings, the impact of discrimination on child health and well-being, the impact of fear and stress on meeting the needs of children, the burden on children serving as liaisons between families and services, the inability of citizenship to protect against the effects of discrimination, positive and hopeful responses to discrimination, and the potential role of education in building a foundation for reducing discrimination (and thus promoting the health and well-being of Latino children) in the future. Conclusions: Discrimination against mixed-status Latino families constitutes a critical threat to the health and well-being of Latino children. Further research should inform immigration policies that support (rather than threaten) the health, well-being, and health care practices that mitigate the stresses experienced by Latino children

Aspects of Black Hole Quantum Mechanics and Thermodynamics in 2+1 Dimensions

We discuss the quantum mechanics and thermodynamics of the (2+1)-dimensional black hole, using both minisuperspace methods and exact results from Chern-Simons theory. In particular, we evaluate the first quantum correction to the black hole entropy. We show that the dynamical variables of the black hole arise from the possibility of a deficit angle at the (Euclidean) horizon, and briefly speculate as to how they may provide a basis for a statistical picture of black hole thermodynamics.Comment: 20 pages and 2 figures, LaTeX, IASSNS-HEP-94/34 and UCD-94-1

Determinants of physicians’ intention to collect data exhaustively in registries: an exploratory study in Bamako’s community health centres

Background: The incomplete collection of health datais a prevalent problem in healthcare systems around theworld, especially in developing countries. Missing datahinders progress in population health and perpetuatesinefficiencies in healthcare systems.Objective: This study aims to identify the factors that predict the intention of physicians practicing in community health centres of Bamako, Mali, to collect data exhaustively in medical registries.Design: A cross sectional studyMethod: In January and February 2011, we conducted a study with a random sample of thirty two physicians practicing in community health centres of Bamako, using a questionnaire. Data was analyzed by using descriptive statistics, correlations and linear regression.Main outcomes measures: Trained investigators administered a questionnaire measuring physicians’ sociodemographic and professional characteristics as well as constructs from the Theory of Planned Behaviour.Results: Our results showed that physicians’ intention to collect data exhaustively is influenced by subjective norms and by the physician’s number of years in practice.Conclusions: the results of this study could be used as a guide for health workers and decision makers to improve the quality of health information collected in community health centers.Keywords: Physicians’ intention, exhaustive data collection, Bamako, Community Health Centre, Missing dat

Global Charges in Chern-Simons theory and the 2+1 black hole

We use the Regge-Teitelboim method to treat surface integrals in gauge theories to find global charges in Chern-Simons theory. We derive the affine and Virasoro generators as global charges associated with symmetries of the boundary. The role of boundary conditions is clarified. We prove that for diffeomorphisms that do not preserve the boundary there is a classical contribution to the central charge in the Virasoro algebra. The example of anti-de Sitter 2+1 gravity is considered in detail.Comment: Revtex, no figures, 26 pages. Important changes introduced. One section added