4,262 research outputs found

    Systematic study of the jet fragmentation function for inclusive jet-production in p+p collisions at sqrt{s}=200 GeV in STAR

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    Jet fragmentation functions measured in e^+e^- and p+\bar{p} experiments are well-described on an inclusive hadron level by QCD-based calculations. Fragmentation is expected to be modified by the presence of a strongly interacting medium, but full theoretical description of this modification must still be developed. It has recently been suggested that particle-identified fragmentation functions may provide additional insight into the processes underlying jet quenching. To assess the applicability of QCD-based fragmentation calculations to RHIC data, and to provide a baseline with which to compare fragmentation function measurements in heavy ion collisions, we present the first measurements of charged hadron and particle-identified fragmentation functions of jets reconstructed via a midpoint-cone algorithm from p+p collisions at 200 GeV in STAR. We study the dependence on jet cone-size and jet-energy, and compare the results to PYTHIA simulations based on the Modified Leading Log Approximation (MLLA).Comment: 6 pages, 5 figures, proceedings of Hard Probes 2008 conferenc

    Examining Manual and Visual Response Inhibition Among ADHD Subtypes

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    This study compared inhibitory functioning among ADHD subtype groups on manual and visual versions of the stop task. Seventy-six children, identified as ADHD/I (n = 16), ADHD/C (n =42), and comparison (n = 18) completed both tasks. Results indicated that both ADHD groups were slower to inhibit responses than the comparison group on both tasks. Comparison children were faster to inhibit than activate responses on both versions of the task. Children in the ADHD groups also demonstrated this robust pattern on the manual task. However, on the visual task, children in the ADHD groups evidenced slowed inhibition comparable to the time required to activate responding. This implies that the visual task is more sensitive to inhibitory impairment in ADHD than the manual task. The ADHD/I group did not differ from children with ADHD/C on most measures, suggesting that the stop task is not effective in differentiating the subtypes. These findings extend work highlighting the role of disinhibition in ADHD, and contrast recent work suggesting divergence between ADHD subtypes

    Gross Domestic Product (GDP) and productivity of schizophrenia trials: an ecological study

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    The 5000 randomised controlled trials (RCTs) in the Cochrane Schizophrenia Group's database affords an opportunity to research for variables related to the differences between nations of their output of schizophrenia trials. Ecological study – investigating the relationship between four economic/demographic variables and number of schizophrenia RCTs per country. The variable with closest correlation was used to predict the expected number of studies. GDP closely correlated with schizophrenia trial output, with 76% of the total variation about the Y explained by the regression line (r = 0.87, 95% CI 0.79 to 0.92, r2 = 0.76). Many countries have a strong tradition of schizophrenia trials, exceeding their predicted output. All nations with no identified trial output had GDPs that predicted zero trial activity. Several nations with relatively small GDPs are, nevertheless, highly productive of trials. Some wealthy countries seem either not to have produced the expected number of randomised trials or not to have disseminated them to the English-speaking world. This hypothesis-generating study could not investigate causal relationships, but suggests, that for those seeking all relevant studies, expending effort searching the scientific literature of Germany, Italy, France, Brazil and Japan may be a good investment

    Smectic-C tilt under shear in Smectic-A elastomers

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    Stenull and Lubensky [Phys. Rev. E {\bf 76}, 011706 (2007)] have argued that shear strain and tilt of the director relative to the layer normal are coupled in smectic elastomers and that the imposition of one necessarily leads to the development of the other. This means, in particular, that a Smectic-A elastomer subjected to a simple shear will develop Smectic-C-like tilt of the director. Recently, Kramer and Finkelmann [arXiv:0708.2024, Phys. Rev. E {\bf 78}, 021704 (2008)] performed shear experiments on Smectic-A elastomers using two different shear geometries. One of the experiments, which implements simple shear, produces clear evidence for the development of Smectic-C-like tilt. Here, we generalize a model for smectic elastomers introduced by Adams and Warner [Phys. Rev. E {\bf 71}, 021708 (2005)] and use it to study the magnitude of Smectic-C-like tilt under shear for the two geometries investigated by Kramer and Finkelmann. Using reasonable estimates of model parameters, we estimate the tilt angle for both geometries, and we compare our estimates to the experimental results. The other shear geometry is problematic since it introduces additional in-plane compressions in a sheet-like sample, thus inducing instabilities that we discuss.Comment: 8 pages, 5 figure

    Inheritance of single copy nuclear genes (SCNGs) in artificial hybrids of Hesperocyparis arizonica x H. macrocarpa: Potential for utilization in the detection of hybridization in natural populations

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    Analyses were performed on 18 artificial hybrids from a cross of Hesperocyparis arizonica (male parent) x H. macrocarpa (female parent) using 9 single copy nuclear genes (SCNGs). Three SCNG were found to be informative: myb, 4CL and CnAIB2. Gene myb contained 5 variable sites, of which site 89 was homozygous (CC, TT) as was site 261 (GG, AA) and useful for the detection of hybridization. All 18 hybrids were heterozygous (CT and GA) at these 2 sites as predicted in hybrids. 4CL contained 8 variable sites, of which 1 site (591) was homozygous (TT, CC) and all 18 hybrids were heterozygous (TC) at this site as expected. CnAIP2 had two variable sites: 301 (AA, AC) and 554 (AG, AA). For site 301, 8 hybrids were AA, and 10 were AC as expected. For site 554, 10 hybrids were AA and 8 were AG, so neither would be useful for unequivocally identifying hybrids. The inheritance of variable sites for the three SCNGs followed simple co-occurrence. Examination of myb in the 18 hybrids revealed 2 cases of cross-over in the pollen gametes

    Oral vitamin C and endothelial function in smokers: short-term improvement, but no sustained beneficial effect

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    AbstractOBJECTIVESTo test the hypothesis that antioxidant therapy would improve endothelial function in smokers.BACKGROUNDSeveral studies have documented a beneficial effect of short-term oral or parenteral vitamin C on endothelial physiology in subjects with early arterial dysfunction. Possible long-term effects of vitamin C on endothelial function, however, are not known.METHODSWe studied the effects of short- and long-term oral vitamin C therapy on endothelial function in 20 healthy young adult smokers (age 36 ± 6 years, 8 male subjects, 21 ± 10 pack-years). Each subject was studied at baseline, 2 h after a single dose of 2 g vitamin C and 8 weeks after taking 1 g vitamin C daily, and after placebo, in a randomized double-blind crossover study. Blood samples were analyzed for plasma ascorbate levels and endothelial function was measured as flow-mediated dilation of the brachial artery, using high resolution ultrasound. Nitroglycerin-mediated dilation (endothelium-independent) was also measured at each visit.RESULTSAt baseline, plasma ascorbate level was low in the smokers (42 ± 21 μmol/liter; normal range, 50 to 150 μmol/liter), increased with vitamin C therapy after 2 h to 120 ± 54 μmol/liter (p < 0.001) and remained elevated after eight weeks of supplementation at 92 ± 32 μmol/liter (p < 0.001, compared with placebo). Flow-mediated dilation, however, increased at 2 h (from 2.8 ± 2.0% to 6.3 ± 2.8%, p < 0.001), but there was no sustained beneficial effect after eight weeks (3.9 ± 3.2%, p = 0.26). Nitroglycerin-mediated dilation was unchanged throughout.CONCLUSIONOral vitamin C therapy improves endothelial dysfunction in the short term in healthy young smokers, but it has no beneficial long-term effect, despite sustained elevation of plasma ascorbate levels

    Masters Athletes: No Evidence of Increased Incidence of Injury in Football Code Athletes

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    The World Masters Games, held quadrennially, is the largest international sporting competition in terms of participant numbers. Yet this cohort remains proportionately under investigated. An online survey using an open-source specialized survey application software program was utilized to investigate the 2009 Sydney World Masters Games (SWMG) football code athletes (association football, touch football, rugby union). A total of 931 masters athletes (28.2% response rate, aged 29 - 72 yrs, mean = 47.6, SD ± 7.1, 52.5% male) completed the survey, with touch football reporting the highest incidence of injury (29.2%) followed by rugby (27.0%) and soccer (21.2%). Analyzing injury data (t-tests, chi square) identified patterns in injury location (legs (11.2%, p \u3c 0.01) followed by knees, feet and ankles) and significant (p \u3c 0.01) classification patterns (muscle/tendon strain/tear (13.0%, p \u3c 0.05), inflammation (6.1%), joint pain (6.0%) and ligament sprain/tear (5.8%)). There were also significant differences (p \u3c 0.01) compared to general and elite sporting population data. For masters football athletes at the SWMG, the injury incidence during preparation for the tournament has similarities to, but is in fact significantly less than for these other sporting populations. Some gender and sport based differences in injury location and classification type were identified. There were also no significant age related changes in injury nature (classification type, location, incidence, time off work or training). Therefore these findings do not support the premise of masters football code athletes having a higher incidence of injury as compared to younger athletes
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