433 research outputs found
Validity and Reliability of the Lesbian, Gay, Bisexual Working Alliance Self-Efficacy Scales
In this paper, the authors report on the development and initial psychometric evaluation of the Lesbian, Gay, and Bisexual Working Alliance Self-Efficacy Scales (LGB-WASES) with data collected from two studies and 534 counseling trainees. Exploratory factor analysis results yielded a 32-item scale with a three-factor model (a) Emotional Bond, (b) Establishing Tasks, and (c) Setting Goals. LGB-WASES scores were internally consistent and remained stable over a 3-week period. Construct validity evidence suggests the LGB-WASES scores were (a) positively related to general perceptions of counseling self-efficacy and multicultural counseling competency, (b) negatively related to attitudes toward lesbians and gay men, and (d) unrelated to social desirability. Recommendations for future research are also discussed
Critical scaling of the a.c. conductivity for a superconductor above Tc
We consider the effects of critical superconducting fluctuations on the
scaling of the linear a.c. conductivity, \sigma(\omega), of a bulk
superconductor slightly above Tc in zero applied magnetic field. The dynamic
renormalization- group method is applied to the relaxational time-dependent
Ginzburg-Landau model of superconductivity, with \sigma(\omega) calculated via
the Kubo formula to O(\epsilon^{2}) in the \epsilon = 4 - d expansion. The
critical dynamics are governed by the relaxational XY-model
renormalization-group fixed point. The scaling hypothesis \sigma(\omega) \sim
\xi^{2-d+z} S(\omega \xi^{z}) proposed by Fisher, Fisher and Huse is explicitly
verified, with the dynamic exponent z \approx 2.015, the value expected for the
d=3 relaxational XY-model. The universal scaling function S(y) is computed and
shown to deviate only slightly from its Gaussian form, calculated earlier. The
present theory is compared with experimental measurements of the a.c.
conductivity of YBCO near Tc, and the implications of this theory for such
experiments is discussed.Comment: 16 pages, submitted to Phys. Rev.
Impact of baryon physics on dark matter structures: a detailed simulation study of halo density profiles
The back-reaction of baryons on the dark matter halo density profile is of
great interest, not least because it is an important systematic uncertainty
when attempting to detect the dark matter. Here, we draw on a large suite of
high resolution cosmological hydrodynamical simulations, to systematically
investigate this process and its dependence on the baryonic physics associated
with galaxy formation. The inclusion of baryons results in significantly more
concentrated density profiles if radiative cooling is efficient and feedback is
weak. The dark matter halo concentration can in that case increase by as much
as 30 (10) per cent on galaxy (cluster) scales. The most significant effects
occur in galaxies at high redshift, where there is a strong anti-correlation
between the baryon fraction in the halo centre and the inner slope of both the
total and the dark matter density profiles. If feedback is weak, isothermal
inner profiles form, in agreement with observations of massive, early-type
galaxies. However, we find that AGN feedback, or extremely efficient feedback
from massive stars, is necessary to match observed stellar fractions in groups
and clusters, as well as to keep the maximum circular velocity similar to the
virial velocity as observed for disk galaxies. These strong feedback models
reduce the baryon fraction in galaxies by a factor of 3 relative to the case
with no feedback. The AGN is even capable of reducing the baryon fraction by a
factor of 2 in the inner region of group and cluster haloes. This in turn
results in inner density profiles which are typically shallower than isothermal
and the halo concentrations tend to be lower than in the absence of baryons.Comment: 20 pages, 14 figures, 1 table. MNRAS in press. Version 2: added a few
references
Sensitivity and Specificity of Multiple Kato-Katz Thick Smears and a Circulating Cathodic Antigen Test for Schistosoma mansoni Diagnosis Pre- and Post-repeated-Praziquantel Treatment
Two Kato-Katz thick smears (Kato-Katzs) from a single stool are currently recommended for diagnosing Schistosoma mansoni infections to map areas for intervention. This ‘gold standard’ has low sensitivity at low infection intensities. The urine point-of-care circulating cathodic antigen test (POC-CCA) is potentially more sensitive but how accurately they detect S. mansoni after repeated praziquantel treatments, their suitability for measuring drug efficacy and their correlation with egg counts remain to be fully understood. We compared the accuracies of one to six Kato-Katzs and one POC-CCA for the diagnosis of S. mansoni in primary-school children who have received zero to ten praziquantel treatments. We determined the impact each diagnostic approach may have on monitoring and evaluation (M&E) and drug-efficacy findings
Distinct Actin and Lipid Binding Sites in Ysc84 Are Required during Early Stages of Yeast Endocytosis
During endocytosis in S. cerevisiae, actin polymerization is proposed to provide the driving force for invagination against the effects of turgor pressure. In previous studies, Ysc84 was demonstrated to bind actin through a conserved N-terminal domain. However, full length Ysc84 could only bind actin when its C-terminal SH3 domain also bound to the yeast WASP homologue Las17. Live cell-imaging has revealed that Ysc84 localizes to endocytic sites after Las17/WASP but before other known actin binding proteins, suggesting it is likely to function at an early stage of membrane invagination. While there are homologues of Ysc84 in other organisms, including its human homologue SH3yl-1, little is known of its mode of interaction with actin or how this interaction affects actin filament dynamics. Here we identify key residues involved both in Ysc84 actin and lipid binding, and demonstrate that its actin binding activity is negatively regulated by PI(4,5)P2. Ysc84 mutants defective in their lipid or actin-binding interaction were characterized in vivo. The abilities of Ysc84 to bind Las17 through its C-terminal SH3 domain, or to actin and lipid through the N-terminal domain were all shown to be essential in order to rescue temperature sensitive growth in a strain requiring YSC84 expression. Live cell imaging in strains with fluorescently tagged endocytic reporter proteins revealed distinct phenotypes for the mutants indicating the importance of these interactions for regulating key stages of endocytosis
Multi-Grid Monte Carlo via Embedding. II. Two-Dimensional Principal Chiral Model
We carry out a high-precision simulation of the two-dimensional
principal chiral model at correlation lengths up to ,
using a multi-grid Monte Carlo (MGMC) algorithm and approximately one year of
Cray C-90 CPU time. We extrapolate the finite-volume Monte Carlo data to
infinite volume using finite-size-scaling theory, and we discuss carefully the
systematic and statistical errors in this extrapolation. We then compare the
extrapolated data to the renormalization-group predictions. The deviation from
asymptotic scaling, which is at , decreases to
at . We also analyze the dynamic critical
behavior of the MGMC algorithm using lattices up to , finding
the dynamic critical exponent
(subjective 68% confidence interval). Thus, for this asymptotically free model,
critical slowing-down is greatly reduced compared to local algorithms, but not
completely eliminated.Comment: self-unpacking archive including .tex, .sty and .ps files; 126 pages
including all figure
TLR9 Agonist Protects Mice from Radiation-Induced Gastrointestinal Syndrome
Radiation-induced gastrointestinal syndrome (RIGS) is due to the clonogenic loss of crypt cells and villi depopulation, resulting in disruption of mucosal barrier, bacterial invasion, inflammation and sepsis. Intestinal macrophages could recognize invading bacterial DNA via TLR9 receptors and transmit regenerative signals to the neighboring crypt. We therefore investigated whether systemic administration of designer TLR9 agonist could ameliorate RIGS by activating TLR9.Male C57Bl6 mice were distributed in four experimental cohorts, whole body irradiation (WBI) (8.4-10.4 Gy), TLR9 agonist (1 mg/kg s.c.), 1 h pre- or post-WBI and TLR9 agonist+WBI+iMyd88 (pretreatment with inhibitory peptide against Myd88). Animals were observed for survival and intestine was harvested for histological analysis. BALB/c mice with CT26 colon tumors in abdominal wall were irradiated with 14 Gy single dose of whole abdominal irradiation (AIR) for tumor growth study.Mice receiving pre-WBI TLR9 agonist demonstrated improvement of survival after 10.4 Gy (p<0.03), 9.4 Gy (p<0.008) and 8.4 Gy (p<0.002) of WBI, compared to untreated or iMyd88-treated controls. Post-WBI TLR9 agonist mitigates up to 8.4 Gy WBI (p<0.01). Histological analysis and xylose absorption test demonstrated significant structural and functional restitution of the intestine in WBI+TLR9 agonist cohorts. Although, AIR reduced tumor growth, all animals died within 12 days from RIGS. TLR9 agonist improved the survival of mice beyond 28 days post-AIR (p<0.008) with significant reduction of tumor growth (p<0.0001).TLR9 agonist treatment could serve both as a prophylactic or mitigating agent against acute radiation syndrome and also as an adjuvant therapy to increase the therapeutic ratio of abdominal Radiation Therapy for Gastro Intestinal malignancies
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