3,713 research outputs found
Single Nucleotide Polymorphism in hsa-mir-196a-2 and Breast Cancer Risk: A Case Control Study
microRNAs are small, non-coding RNAs that influence gene expression on a post-transcriptional level. They participate in diverse biological pathways and may act as either tumor suppressor genes or oncogenes. As they may have an effect on thousands of target mRNAs, single-nucleotide polymorphisms in microRNA genes might have major functional consequences, because the microRNA's properties and/or maturation may change. miR-196a has been reported to be aberrantly expressed in breast cancer tissue. Additionally, the SNP rs11614913 in hsa-mir-196a-2 has been found to be associated with breast cancer risk in some studies although not in others. This study evaluated the association between rs11614913 and breast cancer risk in a Caucasian case-control cohort in Queensland, Australia. Results do not support an association of the tested hsa-mir-196a-2 polymorphism with breast cancer susceptibility in this cohort. As there is a discrepancy between our results and previous findings, it is important to assess the role of rs11614913 in breast cancer by further larger studies investigating different ethnic group
On the topology of stationary black holes
We prove that the domain of outer communication of a stationary, globally
hyperbolic spacetime satisfying the null energy condition must be simply
connected. Under suitable additional hypotheses, this implies, in particular,
that each connected component of a cross-section of the event horizon of a
stationary black hole must have spherical topology.Comment: 7 pages, Late
Measurement of Optical Response of a Detuned Resonant Sideband Extraction Interferometer
We report on the optical response of a suspended-mass detuned resonant
sideband extraction (RSE) interferometer with power recycling. The purpose of
the detuned RSE configuration is to manipulate and optimize the optical
response of the interferometer to differential displacements (induced by
gravitational waves) as a function of frequency, independently of other
parameters of the interferometer. The design of our interferometer results in
an optical gain with two peaks: an RSE optical resonance at around 4 kHz and a
radiation pressure induced optical spring at around 41 Hz. We have developed a
reliable procedure for acquiring lock and establishing the desired optical
configuration. In this configuration, we have measured the optical response to
differential displacement and found good agreement with predictions at both
resonances and all other relevant frequencies. These results build confidence
in both the theory and practical implementation of the more complex optical
configuration being planned for Advanced LIGO.Comment: 6 pages, 4 figures, for submission to Phys Rev Letter
The status of water and sanitation among Pacific Rim nations
Analysis of relationships among national wealth, access to improved water supply and sanitation facilities, and population health indices suggests that the adequacy of water resources at the national level is a poor predictor of economic development - namely, that low water stress is neither necessary nor sufficient for economic development at the present state of water stress among Pacific Rim nations. Although nations differ dramatically in terms of priority provided to improved water and sanitation, there is some level of wealth (per capita GNP) at which all nations promote the development of essential environmental services. Among the Pacific Rim countries for which there are data, no nation with a per capita GNP < US18,000/person-year, however, there are decided differences in the provision of sanitary services (improved water supply and sanitation) among nations with similar economic success. There is a fairly strong relationship between child mortality/life expectancy and access to improved sanitation, as expected from the experiences of developed nations. Here no attempt is made to produce causal relationships among these data. Failure to meet Millennium Development Goals for the extension of improved sanitation is frequently evident in nations with large rural populations. Under those circumstances, capital intensive water and sanitation facilities are infeasible, and process selection for water/wastewater treatment requires an adaptation to local conditions, the use of appropriate materials, etc., constraints that are mostly absent in the developed world. Exceptions to these general ideas exist in water-stressed parts of developed countries, where water supplies are frequently augmented by water harvesting, water reclamation/reuse, and the desalination of brackish water resources. Each of these processes involves public acceptance of water resources that are at least initially of inferior quality. Despite predictions of looming increases in water stress throughout the world, adaptation and resourcefulness generally allow us to meet water demand while pursuing rational economic development, even in the most water-stressed areas of the Pacific Rim
Heisenberg Evolution WKB and Symplectic Area Phases
The Schrodinger and Heisenberg evolution operators are represented in quantum
phase space by their Weyl symbols. Their semiclassical approximations are
constructed in the short and long time regimes. For both evolution problems,
the WKB representation is purely geometrical: the amplitudes are functions of a
Poisson bracket and the phase is the symplectic area of a region in phase space
bounded by trajectories and chords. A unified approach to the Schrodinger and
Heisenberg semiclassical evolutions is developed by introducing an extended
phase space. In this setting Maslov's pseudodifferential operator version of
WKB analysis applies and represents these two problems via a common higher
dimensional Schrodinger evolution, but with different extended Hamiltonians.
The evolution of a Lagrangian manifold in the extended phase space, defined by
initial data, controls the phase, amplitude and caustic behavior. The
symplectic area phases arise as a solution of a boundary condition problem.
Various applications and examples are considered.Comment: 32 pages, 7 figure
Efficient Photometric Selection of Quasars from the Sloan Digital Sky Survey: 100,000 z<3 Quasars from Data Release One
We present a catalog of 100,563 unresolved, UV-excess (UVX) quasar candidates
to g=21 from 2099 deg^2 of the Sloan Digital Sky Survey (SDSS) Data Release One
(DR1) imaging data. Existing spectra of 22,737 sources reveals that 22,191
(97.6%) are quasars; accounting for the magnitude dependence of this
efficiency, we estimate that 95,502 (95.0%) of the objects in the catalog are
quasars. Such a high efficiency is unprecedented in broad-band surveys of
quasars. This ``proof-of-concept'' sample is designed to be maximally
efficient, but still has 94.7% completeness to unresolved, g<~19.5, UVX quasars
from the DR1 quasar catalog. This efficient and complete selection is the
result of our application of a probability density type analysis to training
sets that describe the 4-D color distribution of stars and spectroscopically
confirmed quasars in the SDSS. Specifically, we use a non-parametric Bayesian
classification, based on kernel density estimation, to parameterize the color
distribution of astronomical sources -- allowing for fast and robust
classification. We further supplement the catalog by providing photometric
redshifts and matches to FIRST/VLA, ROSAT, and USNO-B sources. Future work
needed to extend the this selection algorithm to larger redshifts, fainter
magnitudes, and resolved sources is discussed. Finally, we examine some science
applications of the catalog, particularly a tentative quasar number counts
distribution covering the largest range in magnitude (14.2<g<21.0) ever made
within the framework of a single quasar survey.Comment: 35 pages, 11 figures (3 color), 2 tables, accepted by ApJS; higher
resolution paper and ASCII version of catalog available at
http://sdss.ncsa.uiuc.edu/qso/nbckde
Estimating the Cost of Health Care-Associated Infections: Mind Your p's and q's
Monetary valuations of the economic cost of health care-associated infections (HAIs) are important for decision making and should be estimated accurately. Erroneously high estimates of costs, designed to jolt decision makers into action, may do more harm than good in the struggle to attract funding for infection control. Expectations among policy makers might be raised, and then they are disappointed when the reduction in the number of HAIs does not yield the anticipated cost saving. For this article, we critically review the field and discuss 3 questions. Why measure the cost of an HAI? What outcome should be used to measure the cost of an HAI? What is the best method for making this measurement? The aim is to encourage researchers to collect and then disseminate information that accurately guides decisions about the economic value of expanding or changing current infection control activitie
Centerscope
Centerscope, formerly Scope, was published by the Boston University Medical Center "to communicate the concern of the Medical Center for the development and maintenance of improved health care in contemporary society.
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