Isolated Horizons: Hamiltonian Evolution and the First Law

A framework was recently introduced to generalize black hole mechanics by replacing stationary event horizons with isolated horizons. That framework is significantly extended. The extension is non-trivial in that not only do the boundary conditions now allow the horizon to be distorted and rotating, but also the subsequent analysis is based on several new ingredients. Specifically, although the overall strategy is closely related to that in the previous work, the dynamical variables, the action principle and the Hamiltonian framework are all quite different. More importantly, in the non-rotating case, the first law is shown to arise as a necessary and sufficient condition for the existence of a consistent Hamiltonian evolution. Somewhat surprisingly, this consistency condition in turn leads to new predictions even for static black holes. To complement the previous work, the entire discussion is presented in terms of tetrads and associated (real) Lorentz connections.Comment: 56 pages, 1 figure, Revtex; Final Version, to appear in PR

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Understanding the Interactions of Happiness, Self-Rated Health, Mental Feelings, Habit of Eating Healthy and Sport/Activities: A Path Model for Abu Dhabi

Understanding the interactions between happiness, self-perception of health, healthy eating behaviors, physical activities, and psychological feelings or symptoms of mental health provides necessary inputs for social policymaking. Using data from the second cycle of the Abu Dhabi Quality of Life survey, this study examined a path analysis of Abu Dhabi residents’ nature of assimilations between these variables. The results point to the significant association between happiness and self-rated health. In addition, the results portray significant direct paths to happiness from three mental feeling variables—“feeling calm and peaceful”, “having lots of energy”, and “feeling downhearted and depressed”. The variable of “often feeling rushed or pressed for time” shows a direct path to self-rated health only. Eating healthy food is significantly associated with both happiness and self-perception of health. In addition, “often doing physical activities” positively influences happiness. The present study enhances and refines policymakers’ understanding of the considered factors on happiness and self-rated health with further elaborations of the mediating roles of specific well-being determinants. Limitations and future research directions are also discussed

Operations Strategy, Environmental Uncertainty and Performance: A Path Analytic Model of Industries in Developing Countries

We extend the research of Ward et al. [Ward P, Duray R, Leong G, Sum C. Business environment, operations strategy and performance: an empirical study of Singapore manufacturers. Journal of Operations Management 1995;25 99-115] to the business environment of developing industries by adding two neglected environment variables. \u27government laws and regulations\u27 and \u27political consideration\u27. We use a path analytic framework to study the effects of environment on the choice of operations strategy (low cost, quality, flexibility and delivery) and performance (self-reported change in profits) for a sample of United Arab Emirates manufacturers. We test the model suggested by Ward et ar. and then test the extended model suggested for developing industries. For industries that are described as \u27small business\u27 and \u27developing\u27 rather than \u27mature\u27, we identify strong relationships between environmental factors such as labor availability, competitive hostility, government laws and regulations, political concerns and market dynamism and the operations strategy choices encompassed by competitive priorities. The data also indicates, that successful organizations (high performers), adopt competitive priorities that best fits the conditions of the environment, notably stability and dynamism. Results show that most firms accept their environment as given and install the mechanism to react to its forces. High performers match the complexity of their external environment by utilizing environmental variables as sources for effective controls within their organizations. (C) 2000 Elsevier Science Ltd. All rights reserved