Hot electroweak matter near to the endpoint of the phase transition

The electroweak phase transition is investigated near to its endpoint in the framework of an effective three-dimensional model. We measure the very weak interface tension with the tunneling correlation length method. First results for the mass spectrum and the corresponding wave functions in the symmetric phase are presented.Comment: 3 pages, 5 figures, uses espcrc2.sty, contribution to LATTICE9

Sabotage in Contests: A Survey

A contest is a situation in which individuals expend irretrievable resources to win valuable prize(s). ‘Sabotage’ is a deliberate and costly act of damaging a rival’s' likelihood of winning the contest. Sabotage can be observed in, e.g., sports, war, promotion tournaments, political or marketing campaigns. In this article, we provide a model and various perspectives on such sabotage activities and review the economics literature analyzing the act of sabotage in contests. We discuss the theories and evidence highlighting the means of sabotage, why sabotage occurs, and the effects of sabotage on individual players and on overall welfare, along with possible mechanisms to reduce sabotage. We note that most sabotage activities are aimed at the ablest player, the possibility of sabotage reduces productive effort exerted by the players, and sabotage may lessen the effectiveness of public policies, such as affirmative action, or information revelation in contests. We discuss various policies that a designer may employ to counteract sabotage activities. We conclude by pointing out some areas of future research

Where the electroweak phase transition ends

We give a more precise characterisation of the end of the electroweak phase transition in the framework of the effective 3d SU(2)--Higgs lattice model than has been given before. The model has now been simulated at gauge couplings beta_G=12 and 16 for Higgs masses M_H^*=70, 74, 76 and 80 GeV up to lattices 96^3 and the data have been used for reweighting. The breakdown of finite volume scaling of the Lee-Yang zeroes indicates the change from a first order transition to a crossover at lambda_3/g_3^2=0.102(2) in rough agreement with results of Karsch et al (hep-lat/9608087) at \beta_G=9 and smaller lattices. The infinite volume extrapolation of the discontinuity Delta /g_3^2 turns out to be zero at lambda_3/g_3^2=0.107(2) being an upper limit. We comment on the limitations of the second method.Comment: RevTeX, 19 pages, 11 figures, 2 tables; additional MC-data near the endpoint considere

Reinfestation Sources for Chagas Disease Vector, Triatoma infestans, Argentina

Reinfestation by Triatoma infestans after insecticide spraying has caused elimination efforts in the dry Chaco region to fail repeatedly. The sources and spatial extent that need to be considered to understand the reinfestation pattern and to plan a comprehensive control program were studied in 2 adjacent rural communities in northwestern Argentina from 1993 to 1997. The effects of external, residual, and primary sources on the reinfestation pattern were evaluated by using geographic information systems, satellite imagery, spatial statistics, and 5-year retrospective data for 1,881 sites. The reinfestation process depended on primary internal sources and on surrounding infested communities. In the dry Chaco, successfully reducing the risk for reinfestation in a community depends on treating all communities and isolated sites within 1,500 m of the target community. In addition, during the surveillance phase, spraying all sites within 500 m of new foci will delay reinfestation

Planilha eletrônica para o cálculo da reflectância em imagens TM e ETM+ LANDSAT.

A reflectância de culturas agrícolas e de outros alvos da superfície terrestre é um parâmetro intrínseco dos objetos sensoriados e, assim, em muitas situações, deve ser utilizada em lugar dos valores de níveis de cinza normalmente encontrados nas imagens de satélite. Para obter a reflectância de alvos de imagens de satélite é necessário eliminar a interferência atmosférica e realizar uma série de cálculos que envolvem parâmetros do sensor e informações da própria imagem. Automatizar esse procedimento tem como vantagens a agilização do processo e a redução dos riscos de erros durante os cálculos. O objetivo do presente artigo é apresentar uma planilha eletrônica que simplifica e automatiza a transformação dos números digitais das imagens TM e ETM+ dos satélites Landsat 5 e 7 em valores de reflectância, isto é, um parâmetro intrínseco dos objetos sensoriados e, portanto, com significado físico. O método de correção atmosférica empregado é o da subtração de objeto escuro ou DOS. A planilha eletrônica aqui descrita pode ser encontrada no endereço eletrônico http://www.dsr.inpe.br/Calculo_Reflectancia.xls e pode ser utilizada para calcular valores de reflectância em imagens dos sensores Landsat TM e ETM+

Endpoint of the hot electroweak phase transition

We give the nonperturbative phase diagram of the four-dimensional hot electroweak phase transition. The Monte-Carlo analysis is done on lattices with different lattice spacings ($a$). A systematic extrapolation $a \to 0$ is done. Our results show that the finite temperature SU(2)-Higgs phase transition is of first order for Higgs-boson masses $m_H<66.5 \pm 1.4$ GeV. At this endpoint the phase transition is of second order, whereas above it only a rapid cross-over can be seen. The full four-dimensional result agrees completely with that of the dimensional reduction approximation. This fact is of particular importance, because it indicates that the fermionic sector of the Standard Model can be included perturbatively. We obtain that the Higgs-boson endpoint mass in the Standard Model is $72.4 \pm 1.7$ GeV. Taking into account the LEP Higgs-boson mass lower bound excludes any electroweak phase transition in the Standard Model.Comment: Latex, 7 pages, 4 figure

Spatial Re-Establishment Dynamics of Local Populations of Vectors of Chagas Disease

Chagas disease is transmitted by blood-sucking bugs (vectors) and presents a severe public health threat in the Americas. Worldwide there are approximately 10 million people infected with Chagas disease, a disease for which there is currently no effective cure. Vector suppression is the main strategy to control the spread of this disease. Unfortunately, the vectors have been resurgent in some areas. It is important to understand the dynamics of reinfestation where it occurs. Here we show how different models fitted to patch-level bug infestation data can elucidate different aspects of re-establishment dynamics. Our results demonstrated a 6-month time lag between detection of a new infestation and dispersal events, seasonality in dispersal rates and effects of previous vector infestation on subsequent vector establishment rates. In addition we provide estimates of dispersal distances and the effect of insecticide spraying on rates of vector re-establishment. While some of our results confirm previous findings, the effects of season and previous infestation on bug establishment challenge our current understanding of T. infestans ecology and highlight important gaps in our knowledge of T. infestans dispersal