A study of the correlations between jet quenching observables at RHIC

Focusing on four types of correlation plots, $R_{\rm AA}$ vs. $v_2$, $R_{\rm AA}$ vs. $I_{\rm AA}$, $I_{\rm AA}$ vs. $v_2^{I_{\rm AA}}$ and $v_2$ vs.\ $v_2^{I_{\rm AA}}$, we demonstrate how the centrality dependence of \emph{correlations} between multiple jet quenching observables provide valuable insight into the energy loss mechanism in a quark-gluon plasma. In particular we find that a qualitative energy loss model gives a good description of $R_{\rm AA}$ vs.\ $v_2$ only when we take $\Delta E\sim l^3$ and a medium geometry generated by a model of the Color Glass Condensate. This same $\Delta E\sim l^3$ model also qualitatively describes the trigger $p_T$ dependence of $R_{\rm AA}$ vs.\ $I_{\rm AA}$ data and makes novel predictions for the centrality dependence for this $R_{\rm AA}$ vs.\ $I_{\rm AA}$ correlation. Current data suggests, albeit with extremely large uncertainty, that $v_2^{I_{\rm AA}}\gg v_2$, a correlation that is difficult to reproduce in current energy loss models.Comment: 6 pages, 6 figure

On the influence of Stark broadening on Si I lines in stellar atmospheres

We study the influence of Stark broadening and stratification effects on Si\i lines in the rapidly oscillating (roAp) star 10 Aql, where the Si\i 6142.48 \AA and 6155.13 \AA lines are asymmetrical and shifted. First we have calculated Stark broadening parameters using the semiclassical perturbation method for three Si\i lines: 5950.2 \AA, 6142.48 \AA and 6155.13 \AA. We revised the synthetic sp$ calculation code taking into account both Stark width and shift for these lines. From the comparison of our calculations with the observations we found that Stark broadening + the stratification effect can explain asymmetry of the Si\i 6142.48 \AA and 6155.13 \AA lines in the atmospere of roAp star 10 Aql.Comment: Accepted to A&

How African American Adolescents Manage Depression: Being With Others

BACKGROUND: African American (AA) adolescents with depression face serious negative outcomes. Despite racial/ethnic disparities in treatment utilization, few studies have explored how AA adolescents manage their depression. OBJECTIVE: To describe common ways AA adolescents manage depressive symptoms through relationships with people in their lives. DESIGN: Qualitative descriptive methods were used to analyze the narratives of 22 AA young adults who had been depressed as adolescents and 5 AA adolescents in treatment for depression. RESULTS: A typology describing the varied ways AA adolescents manage their depressive symptoms through interactions with other people was constructed and labeled Being With Others. The five categories in the typology are keeping others at bay, striking out at others, seeking help from others, joining in with others, and having others reach out CONCLUSIONS: Clinicians might use the Being With Others typology to guide discussions related to detecting, assessing, and treating AA adolescents with depression

Combined experimental and computational investigations of rhodium-catalysed C-H functionalisation of pyrazoles with alkenes

Detailed experimental and computational studies have been carried out on the oxidative coupling of the alkenes C(2)H(3)Y (Y=CO(2)Me (a), Ph (b), C(O)Me (c)) with 3-aryl-5-R-pyrazoles (R=Me (1 a), Ph (1 b), CF(3) (1 c)) using a [Rh(MeCN)(3)Cp*][PF(6)](2)/Cu(OAc)(2)⋅H(2)O catalyst system. In the reaction of methyl acrylate with 1 a, up to five products (2 aa–6 aa) were formed, including the trans monovinyl product, either complexed within a novel Cu(I) dimer (2 aa) or as the free species (3 aa), and a divinyl species (6 aa); both 3 aa and 6 aa underwent cyclisation by an aza-Michael reaction to give fused heterocycles 4 aa and 5 aa, respectively. With styrene, only trans mono- and divinylation products were observed, whereas with methyl vinyl ketone, a stronger Michael acceptor, only cyclised oxidative coupling products were formed. Density functional theory calculations were performed to characterise the different migratory insertion and β-H transfer steps implicated in the reactions of 1 a with methyl acrylate and styrene. The calculations showed a clear kinetic preference for 2,1-insertion and the formation of trans vinyl products, consistent with the experimental results

Law School Libraries

Ascorbic acid (AA), in popular speech vitamin C, is a commonly known nutrient. It is involved in several biological processes and deficiency can lead to scurvy. Recent publications have shown the impact of AA on epigenetic regulation in mice. Addition of AA, via enzymatic activity, enhances the generation of 5-hydroxymethylcytosine (5hmC), which is an intermediate in active demethylation of DNA. The role of AA on epigenetic changes in humans has to our knowledge never been studied. In this study, naïve CD4+ T cells from blood donors were used as a model system to investigate AAs possible role in methylation changes in the immune system. By using dot-blot assay, hydroxymethylated DNA immunoprecipitation (hmeDIP) and qPCR, changes in methylation executed by AA could be detected. A confirmation of AAs impact on epigenetic changes in mice was observed. AA enhanced the levels of 5hmC compared to untreated cells. The Jurkat cell line, a human T lymphocyte cell line, showed an opposite result. Treatment with AA decreased the levels of 5hmC compared to untreated cells. When comparing this result with the results obtained in human naïve T cells, the same observation was made. The difference between mouse and human in the ability of producing and metabolize AA could be a reason for this opposite result. Since AA had the ability to modify epigenetic changes in primary human CD4+ T cells, the results suggest that AA may have a function in the human immune system