2,263 research outputs found
Rifts in Spreading Wax Layers
We report experimental results on the rift formation between two freezing wax
plates. The plates were pulled apart with constant velocity, while floating on
the melt, in a way akin to the tectonic plates of the earth's crust. At slow
spreading rates, a rift, initially perpendicular to the spreading direction,
was found to be stable, while above a critical spreading rate a "spiky" rift
with fracture zones almost parallel to the spreading direction developed. At
yet higher spreading rates a second transition from the spiky rift to a zig-zag
pattern occurred. In this regime the rift can be characterized by a single
angle which was found to be dependent on the spreading rate. We show that the
oblique spreading angles agree with a simple geometrical model. The coarsening
of the zig-zag pattern over time and the three-dimensional structure of the
solidified crust are also discussed.Comment: 4 pages, Postscript fil
An Experimental Overview of Results Presented at SQM 2006
I have been asked to give an critical overview on the experimental results
shown in the conference with a emphasis of what has been learned and the
challenges that are ahead in trying to understand the physics of the strongly
interacting quark-gluon plasma. I will not try to summarize all of the results
presented, rather I will concentrate primarily on RHIC data from this
conference. Throughout this summary, I will periodically review some of the
previous results for those not familiar with the present state of the field.Comment: 15 pages, 12 Figure
Antiretroviral therapy to prevent HIV acquisition in serodiscordant couples in a hyperendemic community in rural South Africa
Background. Antiretroviral therapy (ART) was highly efficacious in preventing human immunodeficiency virus (HIV) transmission in stable serodiscordant couples in the HPTN-052 study, a resource-intensive randomized controlled trial with near-perfect ART adherence and mutual HIV status disclosure among all participating couples. However, minimal evidence exists of the effectiveness of ART in preventing HIV acquisition in stable serodiscordant couples in "real-life" population-based settings in hyperendemic communities of sub-Saharan Africa, where health systems are typically resource-poor and overburdened, adherence to ART is often low, and partners commonly do not disclose their HIV status to each other.
Methods. Data arose from a population-based open cohort in KwaZulu-Natal, South Africa. A total of 17 016 HIV-uninfected individuals present between January 2005 and December 2013 were included. Interval-censored time-updated proportional hazards regression was used to assess how the ART status affected HIV transmission risk in stable serodiscordant relationships.
Results. We observed 1619 HIV seroconversions in 17 016 individuals, over 60 349 person-years follow-up time. During the follow-up period, 1846 individuals had an HIV-uninfected and 196 had an HIV-infected stable partner HIV incidence was 3.8/100 person-years (PY) among individuals with an HIV-infected partner (95% confidence interval [CI], 2.3-5.6), 1.4/100 PY (.4-3.5) among those with HIV-infected partners receiving ART, and 5.6/100 PY (3.5-8.4) among those with HIV-infected partners not receiving ART. Use of ART was associated with a 77% decrease in HIV acquisition risk among serodiscordant couples (adjusted hazard ratio, 0.23; 95% CI,. 07-.80).
Conclusions. ART initiation was associated with a very large reduction in HIV acquisition in serodiscordant couples in rural KwaZulu-Natal. However, this "real-life" effect was substantially lower than the effect observed in the HPTN-052 trial. To eliminate HIV transmission in serodiscordant couples, additional prevention interventions are probably needed
Halo and association effects:Cognitive biases in teacher attunement to peer-nominated bullies, victims, and prosocial students
This study examined whether teachers’ perceptions of students’ behavior (referring to halo effects) and the behavior of teacher-perceived friends (referring to association effects) influenced teachers’ ability to recognize students identified as bullies, victims, and prosocial by their peers. Data came from 1,458 children (Mage = 10.5, 47.5% girls) and 56 teachers (Mage = 40.8, 66.1% females). Perceived likeability was associated with decreased odds and teachers’ perceptions of popularity and externalizing behavior were associated with increased odds for teacher attunement to bullying. Perceived likeability and affiliation were associated with decreased odds for teacher attunement to victimized students. Teachers’ perceptions of externalizing behavior were associated with decreased odds, whereas teachers’ perceptions of affiliation and academic competence were associated with increased odds for attunement to prosociality. Finally, a positive association was found between teacher attunement and the average behavior of teacher-perceived friends for bullying, victimization, and prosociality
Directed and Elliptic Flow at RHIC
We present the directed flow measurement () from Au+Au collisions at
\sqrtsNN = 62 GeV. Over the pseudorapidity range we have studied, which
covers from -1.2 to 1.2 and , the magnitude of
for charged particles is found to increase monotonously with pseudorapidity for
all centralities. No `` wiggle'', as predicted by various theoretical
models, is observed at midrapidity. Elliptic flow () from moderate high
particles () at \sqrtsNN = 200 GeV is presented as a
function of impact parameter. It is found that models that are based on {\it
jet quenching} alone appear to underpredict at moderate high , while
the model that incorporates both, recombination and fragmentation, describes
the data better.Comment: 6 pages, 4 figures. Proceeding for Hot Quark 04 conference Changes in
the revision are mostly English fixes. v1 versus eta plot is flipped over to
follow the conventio
- …