764 research outputs found
Factors affecting the pre- and post-elective abortion contraception choices in Iowa
To characterize the contraceptive uses and identify contraceptive concerns and preferences among Iowa women seeking abortion
In-orbit performance of the EPIC-MOS detectors on XMM-Newton
XMM-Newton was launched into space on a highly eccentric 48 hour orbit on
December 10th 1999. XMM-Newton is now in its fifth year of operation and has
been an outstanding success, observing the Cosmos with imaging, spectroscopy
and timing capabilities in the X-ray and optical wavebands. The EPIC-MOS CCD
X-ray detectors comprise two out of three of the focal plane instruments on
XMM-Newton. In this paper we discuss key aspects of the current status and
performance history of the charge transfer ineffiency (CTI), energy resolution
and spectral redistribution function (rmf) of EPIC-MOS in its fifth year of
operation.Comment: 8 pages, 10 figures, SPIE Glasgow 21-25 June 2004, Session 548
Rank-(n – 1) convexity and quasiconvexity for divergence free fields
The CAST experiment at CERN (European Organization of Nuclear Research)
searches for axions from the sun. The axion is a pseudoscalar particle that was
motivated by theory thirty years ago, with the intention to solve the strong CP
problem. Together with the neutralino, the axion is one of the most promising
dark matter candidates. The CAST experiment has been taking data during the
last two years, setting an upper limit on the coupling of axions to photons
more restrictive than from any other solar axion search in the mass range below
0.1 eV. In 2005 CAST will enter a new experimental phase extending the
sensitivity of the experiment to higher axion masses. The CAST experiment
strongly profits from technology developed for high energy physics and for
X-ray astronomy: A superconducting prototype LHC magnet is used to convert
potential axions to detectable X-rays in the 1-10 keV range via the inverse
Primakoff effect. The most sensitive detector system of CAST is a spin-off from
space technology, a Wolter I type X-ray optics in combination with a prototype
pn-CCD developed for ESA's XMM-Newton mission. As in other rare event searches,
background suppression and a thorough shielding concept is essential to improve
the sensitivity of the experiment to the best possible. In this context CAST
offers the opportunity to study the background of pn-CCDs and its long term
behavior in a terrestrial environment with possible implications for future
space applications. We will present a systematic study of the detector
background of the pn-CCD of CAST based on the data acquired since 2002
including preliminary results of our background simulations.Comment: 11 pages, 8 figures, to appear in Proc. SPIE 5898, UV, X-Ray, and
Gamma-Ray Space Instrumentation for Astronomy XI
Moving from a Product-Based Economy to a Service-Based Economy for a More Sustainable Future
Traditionally, economic growth and prosperity have been linked with the availability, production and distribution of tangible goods as well as the ability of consumers to acquire such goods. Early evidence regarding this connection dates back to Adam Smith's Wealth of Nations (1776), in which any activity not resulting in the production of a tangible good is characterized as unproductive of any value." Since then, this coupling of economic value and material production has been prevalent in both developed and developing economies throughout the world. One unintended consequence of this coupling has been the exponential increase in the amount of solid waste being generated. The reason is that any production and consumption of material goods eventually generates the equivalent amount of (or even more) waste. Exacerbating this problem is the fact that, with today's manufacturing and supply chain management technologies, it has become cheaper to dispose and replace most products rather than to repair and reuse them. This has given rise to what some call a disposable society." To put things in perspective: In 2012 households in the U.K. generated approximately 22 thousand tons of waste, which amounted to 411 kg of waste generated per person (Department for Environment, Food & Rural Affairs, 2015). During the same time period, households in the U.S. generated 251 million tons of waste, which is equivalent to a person generating approximately 2 kg of waste every day (U.S. Environmental Protection Agency, 2012). Out of these 251 million tons of total waste generated, approximately 20% of the discarded items were categorized as durable goods. The disposal of durable goods is particularly worrisome because they are typically produced using material from non- renewable resources such as iron, minerals, and petroleum-based raw materials
Infant Vaccination Education Preferences among Low-Income Pregnant Women
Childhood vaccination is an important public health intervention, yet many children remain under-vaccinated. The objective of this study was to examine infant vaccination education preferences in a population of low-income pregnant women by ethnicity, nativity, and language. Pregnant women 14–44 y old (n = 335) attending a participating low-income reproductive health clinic in southeast Texas from May 26-July 21, 2017, and who completed a paper survey offered in English and Spanish were included. Participants were asked to complete questions about their demographic characteristics and preferences about infant vaccination education. To examine differences in vaccine education preferences by participant demographic characteristics, chi-squared tests, or Fisher’s exact tests and one-way analysis of variance (ANOVA) were conducted using Stata SE Version 15.1 with α = 0.05. Nearly half (47.5%) of participants considered pregnancy the best time to get information about infant vaccination and were most likely (40.6%) to indicate the nurse who gives vaccines during pregnancy as the health-care worker with whom they would like to discuss infant vaccination. There were no demographic differences in preferred timing of vaccine education delivery or provider who delivers vaccine education. Prenatal, nurse-delivered vaccine educational programs would be well accepted in this low-income population
The effect of interfacial phenomena on gas solubility measurements in molten salts
The behavior of fission gases in molten fuel salt reactors governs activity transport from the reactor and can also affect the performance of the reactor itself. The gas solubility can be described thermodynamically by Henry’s law. However, the coupling of the condensed and gas phases depends on the interfacial area, which is difficult to measure or even to estimate. Surfaces of materials in the reactor will include disperse phases in the salt and porosity within the structural materials, covering a range of compositions and sizes. These attributes can affect measurements of fundamental properties such as gas solubility. Methods to obtain gas solubility, surface tension, interfacial energies, and bubble gas transport are reviewed. Recent data from manometric experiments are interpreted based on xenon sorption onto salt-wetted quartz
Cellular adaptations to hypoxia and acidosis during somatic evolution of breast cancer
Conceptual models of carcinogenesis typically consist of an evolutionary sequence of heritable changes in genes controlling proliferation, apoptosis, and senescence. We propose that these steps are necessary but not sufficient to produce invasive breast cancer because intraductal tumour growth is also constrained by hypoxia and acidosis that develop as cells proliferate into the lumen and away from the underlying vessels. This requires evolution of glycolytic and acid-resistant phenotypes that, we hypothesise, is critical for emergence of invasive cancer. Mathematical models demonstrate severe hypoxia and acidosis in regions of intraductal tumours more than 100 m from the basement membrane. Subsequent evolution of glycolytic and acid-resistant phenotypes leads to invasive proliferation. Multicellular spheroids recapitulating ductal carcinoma in situ (DCIS) microenvironmental conditions demonstrate upregulated glucose transporter 1 (GLUT1) as adaptation to hypoxia followed by growth into normoxic regions in qualitative agreement with model predictions. Clinical specimens of DCIS exhibit periluminal distribution of GLUT-1 and Na+/H+ exchanger (NHE) indicating transcriptional activation by hypoxia and clusters of the same phenotype in the peripheral, presumably normoxic regions similar to the pattern predicted by the models and observed in spheroids. Upregulated GLUT-1 and NHE-1 were observed in microinvasive foci and adjacent intraductal cells. Adaptation to hypoxia and acidosis may represent key events in transition from in situ to invasive cancer
Magnetic field-induced weak-to-strong-link transformation in patterned superconducting films
Ubiquitous in most superconducting materials and a common result of
nanofabrication processes, weak-links are known for their limiting effects on
the transport of electric currents. Still, they are at the root of key features
of superconducting technology. By performing quantitative magneto-optical
imaging experiments and thermomagnetic model simulations, we correlate the
existence of local maxima in the magnetization loops of FIB-patterned Nb films
to a magnetic field-induced weak-to-strong-link transformation increasing their
critical current. This phenomenon arises from the nanoscale interaction between
quantized magnetic flux lines and FIB-induced modifications of the device
microstructure. Under an ac drive field, this leads to a rectified vortex
motion along the weak-link. The reported tunable effect can be exploited in the
development of new superconducting electronic devices, such as flux pumps and
valves, to attenuate or amplify the supercurrent through a circuit element, and
as a strategy to enhance the critical current in weak-link-bearing devices.Comment: 12 pages and 5 figure
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