3,710 research outputs found

    Current quark mass dependence of nucleon magnetic moments and radii

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    A calculation of the current-quark-mass-dependence of nucleon static electromagnetic properties is necessary in order to use observational data as a means to place constraints on the variation of Nature's fundamental parameters. A Poincare' covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is used to calculate this dependence The results indicate that, like observables dependent on the nucleons' magnetic moments, quantities sensitive to their magnetic and charge radii, such as the energy levels and transition frequencies in Hydrogen and Deuterium, might also provide a tool with which to place limits on the allowed variation in Nature's constants.Comment: 23 pages, 2 figures, 4 tables, 4 appendice

    High-throughput amplicon sequencing reveals distinct communities within a corroding concrete sewer system

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    This study investigated the variation in microbially induced concrete corrosion communities at different circumferential locations of a real sewer pipe and the effects of a wastewater flooding event on the community. Three distinct microbial community groups were found in different corrosion samples. The physico-chemical properties of the corrosion layers and the microbial communities were distinct for the cross-sectional positions within the pipe, ie ceiling, wall and tidal zones. The microbial communities detected from the same positions in the pipe were consistent over the length of the pipe, as well as being consistent between the replicate pipes. The dominating ceiling communities were members of the bacterial orders Rhodospirillales, Acidithiobacillales, Actinomycetales, Xanthomonadales and Acidobacteriales. The wall communities were composed of members of the Xanthomonadales, Hydrogenophilales, Chromatiales and Sphingobacteriales. The tidal zones were dominated by eight bacterial and one archaeal order, with the common physiological trait of anaerobic metabolism. Sewage flooding within the sewer system did not change the tidal and wall communities, although the corrosion communities in ceiling samples were notably different, becoming more similar to the wall and tidal samples. This suggests that sewage flooding has a significant impact on the corrosion community in sewers

    Predictors of Chronic Opioid Use: A Population-Level Analysis of North Carolina Cancer Survivors Using Multi-Payer Claims

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    Background: No population-based studies have examined chronic opioid use among cancer survivors who are diverse with respect to diagnosis, age group, and insurance status. Methods: We conducted a retrospective cohort study using North Carolina cancer registry data linked with claims from public and private insurance (2006-2016). We included adults with nonmetastatic cancer who had no prior chronic opioid use (n = 38 366). We used modified Poisson regression to assess the adjusted relative risk of chronic opioid use in survivorship (>90-day continuous supply of opioids in the 13-24 months following diagnosis) associated with patient characteristics. Results: Only 3.0% of cancer survivors in our cohort used opioids chronically in survivorship. Predictors included younger age (adjusted risk ratio [aRR] 50-59 vs 60-69 = 1.23, 95% confidence interval [CI] = 1.05 to 1.43), baseline depression (aRR = 1.22, 95% CI = 1.06 to 1.41) or substance use (aRR = 1.43, 95% CI = 1.15 to 1.78) and Medicaid (aRR vs private = 1.93, 95% CI = 1.56 to 2.40). Survivors who used opioids intermittently (vs not at all) before diagnosis were twice as likely to use opioids chronically in survivorship (aRR = 2.62, 95% CI = 2.28 to 3.02). Those who used opioids chronically (vs intermittently or not at all) during active treatment had a nearly 17-fold increased likelihood of chronic use in survivorship (aRR = 16.65, 95% CI = 14.30 to 19.40). Conclusions: Younger and low-income survivors, those with baseline depression or substance use, and those who require chronic opioid therapy during treatment are at increased risk for chronic opioid use in survivorship. Our findings point to opportunities to improve assessment of psychosocial histories and to engage patients in shared decision-making around long-term pain management, when chronic opioid therapy is required during treatment

    Two- and three-point functions in two-dimensional Landau-gauge Yang-Mills theory: Continuum results

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    We investigate the Dyson-Schwinger equations for the gluon and ghost propagators and the ghost-gluon vertex of Landau-gauge gluodynamics in two dimensions. While this simplifies some aspects of the calculations as compared to three and four dimensions, new complications arise due to a mixing of different momentum regimes. As a result, the solutions for the propagators are more sensitive to changes in the three-point functions and the ansaetze used for them at the leading order in a vertex a expansion. Here, we therefore go beyond this common truncation by including the ghost-gluon vertex self-consistently for the first time, while using a model for the three-gluon vertex which reproduces the known infrared asymptotics and the zeros at intermediate momenta as observed on the lattice. A separate computation of the three-gluon vertex from the results is used to confirm the stability of this behavior a posteriori. We also present further arguments for the absence of the decoupling solution in two dimensions. Finally, we show how in general the infrared exponent kappa of the scaling solutions in two, three and four dimensions can be changed by allowing an angle dependence and thus an essential singularity of the ghost-gluon vertex in the infrared.Comment: 24 pages; added references, improved choices of parameters for vertex models; identical to version published in JHE

    Personal health promotion at US medical schools: a quantitative study and qualitative description of deans' and students' perceptions

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    BACKGROUND: Prior literature has shown that physicians with healthy personal habits are more likely to encourage patients to adopt similar habits. However, despite the possibility that promoting medical student health might therefore efficiently improve patient outcomes, no one has studied whether such promotion happens in medical school. We therefore wished to describe both typical and outstanding personal health promotion environments experienced by students in U.S. medical schools. METHODS: We collected information through four different modalities: a literature review, written surveys of medical school deans and students, student and dean focus groups, and site visits at and interviews with medical schools with reportedly outstanding student health promotion programs. RESULTS: We found strong correlations between deans' and students' perceptions of their schools' health promotion environments, including consistent support of the idea of schools' encouraging healthy student behaviors, with less consistent follow-through by schools on this concept. Though students seemed to have thought little about the relationships between their own personal and clinical health promotion practices, deans felt strongly that faculty members should model healthy behaviors. CONCLUSIONS: Deans' support of the relationship between physicians' personal and clinical health practices, and concern about their institutions' acting on this relationship augurs well for the role of student health promotion in the future of medical education. Deans seem to understand their students' health environment, and believe it could and should be improved; if this is acted on, it could create important positive changes in medical education and in disease prevention

    Timed inhibition of CDC7 increases CRISPR-Cas9 mediated templated repair.

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    Repair of double strand DNA breaks (DSBs) can result in gene disruption or gene modification via homology directed repair (HDR) from donor DNA. Altering cellular responses to DSBs may rebalance editing outcomes towards HDR and away from other repair outcomes. Here, we utilize a pooled CRISPR screen to define host cell involvement in HDR between a Cas9 DSB and a plasmid double stranded donor DNA (dsDonor). We find that the Fanconi Anemia (FA) pathway is required for dsDonor HDR and that other genes act to repress HDR. Small molecule inhibition of one of these repressors, CDC7, by XL413 and other inhibitors increases the efficiency of HDR by up to 3.5 fold in many contexts, including primary T cells. XL413 stimulates HDR during a reversible slowing of S-phase that is unexplored for Cas9-induced HDR. We anticipate that XL413 and other such rationally developed inhibitors will be useful tools for gene modification

    Deglacial changes in flow and frontal structure through the Drake Passage

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    © 2017 Elsevier B.V. The oceanic gateways of the Drake Passage and the Agulhas Current are critical locations for the inflow of intermediate-depth water masses to the Atlantic, which contribute to the shallow return flow that balances the export of deep water from the North Atlantic. The thermohaline properties of northward flowing intermediate water are ultimately determined by the inflow of water through oceanic gateways. Here, we focus on the less well-studied “Cold Water Route” through the Drake Passage. We present millennially-resolved bottom current flow speed and sea surface temperature records downstream of the Drake Passage spanning the last 25,000 yr. We find that prior to 15 ka, bottom current flow speeds at sites in the Drake Passage region were dissimilar and there was a marked anti-phasing between sea surface temperatures at sites upstream and downstream of the Drake Passage. After 14 ka, we observe a remarkable convergence of flow speeds coupled with a sea surface temperature phase change at sites upstream and downstream of Drake Passage. We interpret this convergence as evidence for a significant southward shift of the sub-Antarctic Front from a position north of Drake Passage. This southward shift increased the through-flow of water from the Pacific, likely reducing the density of Atlantic Intermediate Water. The timing of the southward shift in the sub-Antarctic Front is synchronous with a major re-invigoration of Atlantic Meridional Overturning Circulation, with which, we argue, it may be linked
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