48,707 research outputs found
Uniqueness on the Class of Odd-Dimensional Starlike Obstacles with Cross Section Data
We determine the uniqueness on starlike obstacles by using the cross section
data. We see cross section data as spectral measure in polar coordinate at far
field. Cross section scattering data suffice to give the local behavior of the
wave trace. These local trace formulas contain the geometric information on the
obstacle. Local wave trace behavior is connected to the cross section
scattering data by Lax-Phillips' formula. Once the scattering data are
identical from two different obstacles, the short time behavior of the
localized wave trace is expected to give identical heat/wave invariants
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Urban air pollution and health inequities: a workshop report.
Over the past three decades, an array of legislation with attendant regulations has been implemented to enhance the quality of the environment and thereby improve the public's health. Despite the many beneficial changes that have followed, there remains a disproportionately higher prevalence of harmful environmental exposures, particularly air pollution, for certain populations. These populations most often reside in urban settings, have low socioeconomic status, and include a large proportion of ethnic minorities. The disparities between racial/ethnic minority and/or low-income populations in cities and the general population in terms of environmental exposures and related health risks have prompted the "environmental justice" or "environmental equity" movement, which strives to create cleaner environments for the most polluted communities. Achieving cleaner environments will require interventions based on scientific data specific to the populations at risk; however, research in this area has been relatively limited. To assess the current scientific information on urban air pollution and its health impacts and to help set the agenda for immediate intervention and future research, the American Lung Association organized an invited workshop on Urban Air Pollution and Health Inequities held 22-24 October 1999 in Washington, DC. This report builds on literature reviews and summarizes the discussions of working groups charged with addressing key areas relevant to air pollution and health effects in urban environments. An overview was provided of the state of the science for health impacts of air pollution and technologies available for air quality monitoring and exposure assessment. The working groups then prioritized research needs to address the knowledge gaps and developed recommendations for community interventions and public policy to begin to remedy the exposure and health inequities
Supersymmetric Grand Unified Models without Adjoint Higgs Fields
We discuss two classes of supersymmetric grand unified theories based on
extended gauge groups and . Effective adjoint fields of each gauge group SO(10) are argued to be
formed from combining two Higgs fields in fundamental representation of the
extended gauge groups, one obtaining its VEV along the diagonal
direction and the other acquiring its VEV along the diagonal or its subgroup direction. Thus experimentally acceptable fermion mass
matrices, such as Georgi-Jarlskog ansatz, with successful GUT mass relations
can be constructed in these theories.Comment: 23 pages, 1 figure and 3 table
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