12,398 research outputs found
Spin Observables for Polarizing Antiprotons
The PAX project at GSI Darmstadt plans to polarize an antiproton beam by
repeated interaction with a hydrogen target in a storage ring. Many of the beam
particles are required to remain within the ring after interaction with the
target, so small scattering angles are important. Hence we concentrate on low
momentum transfer (small t), a region where electromagnetic effects dominate
the hadronic effects. A colliding beam of polarized electrons with energy
sufficient to provide scattering of antiprotons beyond ring acceptance may
polarize an antiproton beam by spin filtering. Expressions for spin observables
are provided and are used to estimate the rate of buildup of polarization of an
antiproton beam.Comment: 4 pages, 2 figures, to be published in the Proceedings of the 17th
International Spin Physics Symposium (SPIN 2006), Kyoto, Japan; October 2-7,
200
Dynamics of polarization buildup by spin filtering
There has been much recent research into polarizing an antiproton beam,
instigated by the recent proposal from the PAX (Polarized Antiproton
eXperiment) project at GSI Darmstadt. It plans to polarize an antiproton beam
by repeated interaction with a polarized internal target in a storage ring. The
method of polarization by spin filtering requires many of the beam particles to
remain within the ring after scattering off the polarized internal target via
electromagnetic and hadronic interactions. We present and solve sets of
differential equations which describe the buildup of polarization by spin
filtering in many different scenarios of interest to projects planning to
produce high intensity polarized beams. These scenarios are: 1) spin filtering
of a fully stored beam, 2) spin filtering while the beam is being accumulated,
i.e. unpolarized particles are continuously being fed into the beam, 3) the
particle input rate is equal to the rate at which particles are being lost due
to scattering beyond ring acceptance angle, the beam intensity remaining
constant, 4) increasing the initial polarization of a stored beam by spin
filtering, 5) the input of particles into the beam is stopped after a certain
amount of time, but spin filtering continues. The rate of depolarization of a
stored polarized beam on passing through an electron cooler is also shown to be
negligible.Comment: 15 pages, references added, introduction elaborated on, some
variables defined in more detail. Submitted to Eur. Phys. J.
A Buffer Stocks Model for Stabilizing Price of Staple Food with Considering the Expectation of Non Speculative Wholesaler
This paper is a study of price stabilization in the
staple food distribution system. All stakeholders experience
market risks due to some possibility causes of price volatility.
Many models of price stabilization had been developed by
employing several approaches such as floor-ceiling prices,
buffer funds, export or import taxes, and subsidies. In the
previous researches, the models were expanded to increase the
purchasing price for producer and decrease the selling price
for consumer. Therefore, the policy can influence the losses for
non-speculative wholesaler that is reflected by the descending
of selling quantity and ascending of the stocks. The objective of
this model is not only to keep the expectation of both producer
and consumer, but also to protect non-speculative wholesaler
from the undesirable result of the stabilization policy. A
nonlinear programming model was addressed to determine the
instruments of intervention program. Moreover, the result
shows that the wholesaler behavior affects the intervention
costs.
Index Terms Buffer stocks, Price stabilization, Nonlinear
programming, Wholesaler behavior
The ATLAS-SPT Radio Survey of Cluster Galaxies
Using a high-performance computing cluster to mosaic 4,787 pointings, we have
imaged the 100 sq. deg. South Pole Telescope (SPT) deep-field at 2.1 GHz using
the Australian Telescope Compact Array to an rms of 80 Jy and a resolution
of 8". Our goal is to generate an independent sample of radio-selected galaxy
clusters to study how the radio properties compare with cluster properties at
other wavelengths, over a wide range of redshifts in order to construct a
timeline of their evolution out to . A preliminary analysis of the
source catalogue suggests there is no spatial correlation between the clusters
identified in the SPT-SZ catalogue and our wide-angle tail galaxies.Comment: 9 pages, 4 figures. Submitted to Proceedings of Science for "The many
facets of extragalactic radio surveys: towards new scientific challenges",
Bologna, Italy 20-23 October 2015 (EXTRA-RADSUR2015
The Spatial Correlation of Bent-Tail Galaxies and Galaxy Clusters
We have completed a deep radio continuum survey covering 86 square degrees of
the Spitzer-South Pole Telescope deep field to test whether bent-tail galaxies
are associated with galaxy clusters. We present a new catalogue of 22 bent-tail
galaxies and a further 24 candidate bent-tail galaxies. Surprisingly, of the 8
bent-tail galaxies with photometric redshifts, only two are associated with
known clusters. While the absence of bent-tail sources in known clusters may be
explained by effects such as sensitivity, the absence of known clusters
associated with most bent-tail galaxies casts doubt upon current models of
bent-tail galaxies.Comment: Accepted by MNRA
A non-Abelian Higgs model with instantons and Sphaleron
We present a SU(2) X SU(2) X U(1) model in (3+1) dimensions, which has instanton solutions in R_4, and a sphaleron on R_3 in the static limit
âI wish Iâd told themâ: a qualitative study examining the unmet psychosexual needs of prostate cancer patients during follow-up after treatment
<b>Objective</b> To gain insight into patients' experiences of follow-up care after treatment for prostate cancer and identify unmet psychosexual needs.<p></p>
<b>Methods</b> Semi-structured interviews were conducted with a purposive sample of 35 patients aged 59-82 from three UK regions. Partners were included in 18 interviews. Data were analyzed using constant comparison. <p></p>
<b>Results</b> (1) Psychosexual problems gained importance over time, (2) men felt they were rarely invited to discuss psychosexual side effects within follow-up appointments and lack of rapport with health care professionals made it difficult to raise problems themselves, (3) problems were sometimes concealed or accepted and professionals' attempts to explore potential difficulties were resisted by some, and (4) older patients were too embarrassed to raise psychosexual concerns as they felt they would be considered 'too old' to be worried about the loss of sexual function.<p></p>
<b>Conclusion</b> Men with prostate cancer, even the very elderly, have psychosexual issues for variable times after diagnosis. These are not currently always addressed at the appropriate time for the patient.Practice implications Assessments of psychosexual problems should take place throughout the follow-up period, and not only at the time of initial treatment. Further research examining greater willingness or reluctance to engage with psychosexual interventions may be particularly helpful in designing future intervention
Impact of an integrated nutrition intervention on nutrient intakes, morbidity and growth of rural Burkinabe preschool children
Iron deficiency and undernutrition often co-exist among children and the prevalence in sub-Saharan African is high. In Burkina Faso, 92% of children under the age of five years were anaemic and 39% were stunted in 2003 according to Demographics and health survey. Risk factors include inadequate dietary intakes and infections that often occur concomitantly. Orphans and vulnerable children who are already atincreased risk for poor psycho-emotional development due to their social status are particularly susceptible to malnutrition. Therefore, there is a challenge to develop effective interventions that address the multiple risk factors of nutritional deficiencies in these children. An integrated nutrition intervention including dietary modification and changes in hygiene practices was implemented targeting a group of preschoolorphans and vulnerable children living in group foster homes. The amount of iron-rich foods particularly goat meat and condiments as well as citrus fruits were increased in the diet. The hygiene component of the intervention focused on handwashing, eating in individual plates, food storage and stool disposal. All members of the foster homesat large benefitted from the activities of the intervention; however, measurements and impact evaluation focused on preschool children (12 - 72 months). Energy and nutrient intakes, anthropometric indices and morbidity including diarrhoea, fever, vomiting and respiratory infections were assessed at baseline and after 18 weeks. Mean bioavailable iron intake was increased from 0.4 to 0.9 mg/d. The intervention resulted in a decrease in the prevalence of inadequate intakes for energy, proteins and most micronutrients. The intervention increased the meat-fish-poultry contribution to energy and iron intakes from 1.6 to 3.5% and from 5.2 to 7.9%, respectively. There was also a decrease in the incidence of infection (from 73 to 9%, p<0.01) and overall orbidity (from 39 to 15%, p<0.05) most likely due to deworming and improvementsin hygiene behaviours. Contrary to baseline, helminths such as Hymelolepis nana,Strongyloïżœdes stercoralis and Necator americanus that often cause blood loss were rarely found at the end of the intervention. The overall changes resulted in improvements in height-for-age z-score (-1.63 to -1.27, p<0.01) and weight-for-age zscore (-1.22 to -1.06, p<0.05). In conclusion, an intervention that targets bioavailableiron and hygiene behaviours improved child growth, iron status and overall morbidity in areas of high incidence of infection
Abnormal infant islet morphology precedes insulin resistance in PCOS-like monkeys.
Polycystic ovary syndrome (PCOS) is prevalent in reproductive-aged women and confounded by metabolic morbidities, including insulin resistance and type 2 diabetes. Although the etiology of PCOS is undefined, contribution of prenatal androgen (PA) exposure has been proposed in a rhesus monkey model as premenopausal PA female adults have PCOS-like phenotypes in addition to insulin resistance and decreased glucose tolerance. PA female infants exhibit relative hyperinsulinemia, suggesting prenatal sequelae of androgen excess on glucose metabolism and an antecedent to future metabolic disease. We assessed consequences of PA exposure on pancreatic islet morphology to identify evidence of programming on islet development. Islet counts and size were quantified and correlated with data from intravenous glucose tolerance tests (ivGTT) obtained from dams and their offspring. Average islet size was decreased in PA female infants along with corresponding increases in islet number, while islet fractional area was preserved. Infants also demonstrated an increase in both the proliferation marker Ki67 within islets and the beta to alpha cell ratio suggestive of enhanced beta cell expansion. PA adult females have reduced proportion of small islets without changes in proliferative or apoptotic markers, or in beta to alpha cell ratios. Together, these data suggest in utero androgen excess combined with mild maternal glucose intolerance alter infant and adult islet morphology, implicating deviant islet development. Marked infant, but subtle adult, morphological differences provide evidence of islet post-natal plasticity in adapting to changing physiologic demands: from insulin sensitivity and relative hypersecretion to insulin resistance and diminished insulin response to glucose in the mature PCOS-like phenotype
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