2,663 research outputs found
Exploring barriers to 'Respondent driven sampling' in sex worker and drug-injecting sex worker populations in Eastern Europe
Respondent driven sampling (RDS) has been used in several counties to sample injecting drug users, sex workers (SWs) and men who have sex with men and as a means of collecting behavioural and biological health data. We report on the use of RDS in three separate studies conducted among SWs between 2004 and 2005 in the Russian Federation, Serbia, and Montenegro. Findings suggest that there are limitations associated with the use of RDS in SW populations in these regions. Findings highlight three main factors that merit further investigation as a means of assessing the feasibility and appropriateness of RDS in this high risk population: the network characteristics of SWs; the appropriate level of participant incentives; and lack of service contact. The highly controlled and hidden nature of SW organizations and weak SW social networks in the region can combine to undermine assumptions underpinning the feasibility of RDS approaches and potentially severely limit recruitment. We discuss the implications of these findings for recruitment and the use of monetary and non-monetary incentives in future RDS studies of SW populations in Eastern Europe
3D-4D Interlinkage Of qqq Wave Functions Under 3D Support For Pairwise Bethe-Salpeter Kernels
Using the method of Green's functions within a Bethe-Salpeter framework
characterized by a pairwise qq interaction with a Lorentz-covariant 3D support
to its kernel, the 4D BS wave function for a system of 3 identical relativistic
spinless quarks is reconstructed from the corresponding 3D form which satisfies
a fully connected 3D BSE. This result is a 3-body generalization of a similar
2-body result found earlier under identical conditions of a 3D support to the
corresponding qq-bar BS kernel under Covariant Instaneity (CIA for short). (The
generalization from spinless to fermion quarks is straightforward).
To set the CIA with 3D BS kernel support ansatz in the context of
contemporary approaches to the qqq baryon problem, a model scalar 4D qqq BSE
with pairwise contact interactions to simulate the NJL-Faddeev equations is
worked out fully, and a comparison of both vertex functions shows that the CIA
vertex reduces exactly to the NJL form in the limit of zero spatial range. This
consistency check on the CIA vertex function is part of a fuller accounting for
its mathematical structure whose physical motivation is traceable to the role
of `spectroscopy' as an integral part of the dynamics.Comment: 20 pages, Latex, submitted via the account of K.-C. Yan
Investigation of top mass measurements with the ATLAS detector at LHC
Several methods for the determination of the mass of the top quark with the
ATLAS detector at the LHC are presented. All dominant decay channels of the top
quark can be explored. The measurements are in most cases dominated by
systematic uncertainties. New methods have been developed to control those
related to the detector. The results indicate that a total error on the top
mass at the level of 1 GeV should be achievable.Comment: 47 pages, 40 figure
Differential Transverse Flow in Central C-Ne and C-Cu Collisions at 3.7 GeV/nucleon
Differential transverse flow of protons and pions in central C-Ne and C-Cu
collisions at a beam energy of 3.7 GeV/nucleon was measured as a function of
transverse momentum at the SKM-200-GIBS setup of JINR. In agreement with
predictions of a transversely moving thermal model, the strength of proton
differential transverse flow is found to first increase gradually and then
saturate with the increasing transverse momentum in both systems. While pions
are preferentially emitted in the same direction of the proton transverse flow
in the reaction of C-Ne, they exhibit an anti-flow to the opposote direction of
the proton transverse flow in the reaction of C-Cu due to stronger shadowing
effects of the heavier target in thr whole range of transverse momentum.Comment: 15 pages, 5 figure
Cascades with Adjoint Matter: Adjoint Transitions
A large class of duality cascades based on quivers arising from non-isolated
singularities enjoy adjoint transitions - a phenomenon which occurs when the
gauge coupling of a node possessing adjoint matter is driven to strong coupling
in a manner resulting in a reduction of rank in the non-Abelian part of the
gauge group and a subsequent flow to weaker coupling. We describe adjoint
transitions in a simple family of cascades based on a Z2-orbifold of the
conifold using field theory. We show that they are dual to Higgsing and produce
varying numbers of U(1) factors, moduli, and monopoles in a manner which we
calculate. This realizes a large family of cascades which proceed through
Seiberg duality and Higgsing. We briefly describe the supergravity limit of our
analysis, as well as a prescription for treating more general theories. A
special role is played by N=2 SQCD. Our results suggest that additional light
fields are typically generated when UV completing certain constructions of
spontaneous supersymmetry breaking into cascades, potentially leading to
instabilities.Comment: 29 pages, a few typos fixed, improved discussion, added figure; now
there is 1 figur
1000 Norms Project: Protocol of a cross-sectional study cataloging human variation
Background Clinical decision-making regarding diagnosis and management largely depends on comparison with healthy or ‘normal’ values. Physiotherapists and researchers therefore need access to robust patient-centred outcome measures and appropriate reference values. However there is a lack of high-quality reference data for many clinical measures. The aim of the 1000 Norms Project is to generate a freely accessible database of musculoskeletal and neurological reference values representative of the healthy population across the lifespan. Methods/design In 2012 the 1000 Norms Project Consortium defined the concept of ‘normal’, established a sampling strategy and selected measures based on clinical significance, psychometric properties and the need for reference data. Musculoskeletal and neurological items tapping the constructs of dexterity, balance, ambulation, joint range of motion, strength and power, endurance and motor planning will be collected in this cross-sectional study. Standardised questionnaires will evaluate quality of life, physical activity, and musculoskeletal health. Saliva DNA will be analysed for the ACTN3 genotype (‘gene for speed’). A volunteer cohort of 1000 participants aged 3 to 100 years will be recruited according to a set of self-reported health criteria. Descriptive statistics will be generated, creating tables of mean values and standard deviations stratified for age and gender. Quantile regression equations will be used to generate age charts and age-specific centile values. Discussion This project will be a powerful resource to assist physiotherapists and clinicians across all areas of healthcare to diagnose pathology, track disease progression and evaluate treatment response. This reference dataset will also contribute to the development of robust patient-centred clinical trial outcome measures
The Northern ROSAT All-Sky (NORAS) Galaxy Cluster Survey I: X-ray Properties of Clusters Detected as Extended X-ray Sources
In the construction of an X-ray selected sample of galaxy clusters for
cosmological studies, we have assembled a sample of 495 X-ray sources found to
show extended X-ray emission in the first processing of the ROSAT All-Sky
Survey. The sample covers the celestial region with declination and galactic latitude and comprises sources with
a count rate counts s and a source extent likelihood of 7. In
an optical follow-up identification program we find 378 (76%) of these sources
to be clusters of galaxies. ...Comment: 61 pages; ApJS in press; fixed bug in table file; also available at
(better image quality) http://www.xray.mpe.mpg.de/theorie/NORAS
Monopoles and Knots in Skyrme Theory
We show that the Skyrme theory actually is a theory of monopoles which allows
a new type of solitons, the topological knots made of monopole-anti-monopole
pair,which is different from the well-known skyrmions. Furthermore, we derive a
generalized Skyrme action from the Yang-Mills action of QCD, which we propose
to be an effective action of QCD in the infra-red limit. We discuss the
physical implications of our results.Comment: 4 pages. Phys. Rev. Lett. in pres
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