49 research outputs found

    Hadron Spectrum in a Two-Colour Baryon-Rich Medium

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    The hadron spectrum of SU(2) lattice gauge theory with two flavours of Wilson quark is studied on an 8^3x16 lattice using all-to-all propagators, with particular emphasis on the dependence on quark chemical potential mu. As mu is increased from zero the diquark states with non-zero baryon number B respond as expected, while states with B=0 remain unaffected until the onset of non-zero baryon density at mu=m_pi/2. Post onset the pi-meson mass increases in accordance with chiral perturbation theory while the rho becomes lighter. In the diquark sector a Goldstone state associated with a superfluid ground state can be identified. A further consequence of superfluidity is an approximate degeneracy between mesons and baryons with the same spacetime and isospin quantum numbers. Finally we find tentative evidence for the binding of states with kaon quantum numbers within the baryonic medium.Comment: 14 pages, 5 figure

    The Abelianization of QCD Plasma Instabilities

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    QCD plasma instabilities appear to play an important role in the equilibration of quark-gluon plasmas in heavy-ion collisions in the theoretical limit of weak coupling (i.e. asymptotically high energy). It is important to understand what non-linear physics eventually stops the exponential growth of unstable modes. It is already known that the initial growth of plasma instabilities in QCD closely parallels that in QED. However, once the unstable modes of the gauge-fields grow large enough for non-Abelian interactions between them to become important, one might guess that the dynamics of QCD plasma instabilities and QED plasma instabilities become very different. In this paper, we give suggestive arguments that non-Abelian self-interactions between the unstable modes are ineffective at stopping instability growth, and that the growing non-Abelian gauge fields become approximately Abelian after a certain stage in their growth. This in turn suggests that understanding the development of QCD plasma instabilities in the non-linear regime may have close parallels to similar processes in traditional plasma physics. We conjecture that the physics of collisionless plasma instabilities in SU(2) and SU(3) gauge theory becomes equivalent, respectively, to (i) traditional plasma physics, which is U(1) gauge theory, and (ii) plasma physics of U(1)x U(1) gauge theory.Comment: 36 pages; 15 figures [minor changes made to text, and new figure added, to reflect published version

    The Chiral Fermion Meson Model at Finite Temperature

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    We study the chiral fermion meson model which is the well known linear sigma model of Gell-Mann-and-Levy at finite temperature.A modified self-consistent resummation (MSCR) which resums higher order terms in the perturbative expansion is proposed. It is shown that with the MSCR the problem of tachyonic masses is solved, the renormalization of the gap equations is carried out and the Goldstone's theorem is verified. We also apply the method to investigate another known case at high temperature and compare with results found in the literature.Comment: 31 pages, 9 EPS figures. Final version with extended Concluding Remarks section, accepted for publication in Phys. Rev.

    Bedside rationing by general practitioners: A postal survey in the Danish public healthcare system

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    <p>Abstract</p> <p>Background</p> <p>It is ethically controversial whether medical doctors are morally permitted to ration the care of their patients at the bedside. To explore whether general practitioners in fact do ration in this manner we conducted a study within primary care in the Danish public healthcare system. The purpose of the study was to measure the extent to which general practitioners (GPs) would be willing to factor in cost-quality trade-offs when prescribing medicine, and to discover whether, and if so to what extent, they believe that patients should be informed about this.</p> <p>Methods</p> <p>Postal survey of 600 randomly selected Danish GPs, of which 330 responded to the questionnaire. The Statistical Package for the Social Sciences (SPSS, version 14.0) was used to produce general descriptive statistics. Significance was calculated with the McNemar and the chi-square test. The main outcome measures of the study were twofold: an assessment of the proportion of GPs who, in a mainly hypothetical setting, would consider cost-quality trade-offs relevant to their clinical decision-making given their economic impact on the healthcare system; and a measure of the extent to which they would disclose this information to patients.</p> <p>Results</p> <p>In the hypothetical setting 95% of GPs considered cost-quality trade-offs relevant to their clinical decision-making given the economic impact of such trade-offs on the healthcare system. In all 90% stated that this consideration had been relevant in clinical decision-making within the last month. In the hypothetical setting 55% would inform their patients that they considered a cost-quality trade-off relevant to their clinical decisions given the economic impact of such trade-offs on the healthcare system. The most common reason (68%) given for not wanting to inform patients about this matter was the belief that the information would not prove useful to patients. In the hypothetical setting cost-quality trade-offs were considered relevant significantly more often in connection with concerns about costs to the patient (86%) than they were in connection with concerns about costs to the healthcare system (55%; p < 0.001).</p> <p>Conclusion</p> <p>Although readiness to consider cost-quality trade-offs relevant to clinical decisions is prevalent among GPs in Denmark, only half of GPs would disclose to patients that they consider this relevant to their clinical decision-making. The results of this study raise two important ethical problems. First, under Danish law physicians are required to inform patients about all equal treatments. The fact that only a few GPs would inform their patients about all of the relevant treatments therefore seems to contravene Danish law. Second, it is ethically controversial that physicians act as economic gatekeepers.</p

    Role for a Web-Based Intervention to Alleviate Distress in People With Newly Diagnosed Testicular Cancer: Mixed Methods Study

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    BackgroundDistress is common immediately after diagnosis of testicular cancer. It has historically been difficult to engage people in care models to alleviate distress because of complex factors, including differential coping strategies and influences of social gender norms. Existing support specifically focuses on long-term survivors of testicular cancer, leaving an unmet need for age-appropriate and sex-sensitized support for individuals with distress shortly after diagnosis. ObjectiveWe evaluated a web-based intervention, Nuts & Bolts, designed to provide support and alleviate distress after diagnosis of testicular cancer. MethodsUsing a mixed methods design to evaluate the acceptability, feasibility, and impact of Nuts & Bolts on distress, we randomly assigned participants with recently diagnosed testicular cancer (1:1) access to Nuts & Bolts at the time of consent (early) or alternatively, 1 week later (day 8; delayed). Participants completed serial questionnaires across a 4- to 5-week period to evaluate levels of distress (measured by the National Comprehensive Cancer Network Distress Thermometer [DT]; scored 0-10), anxiety, and depression (Hospital Anxiety and Depression Score [HADS]–Anxiety and HADS-Depression; each scored 0-21). The primary end point was change in distress between consent and day 8. Secondary end points of distress, anxiety, and depression were assessed at defined intervals during follow-up. Optional, semistructured interviews occurring after completion of quantitative assessments were thematically analyzed. ResultsOverall, 39 participants were enrolled in this study. The median time from orchidectomy to study consent was 14.8 (range 3-62) days. Moderate or high levels of distress evaluated using DT were reported in 58% (23/39) of participants at consent and reduced to 13% (5/38) after 1 week of observation. Early intervention with Nuts & Bolts did not significantly decrease the mean DT score by day 8 compared with delayed intervention (early: 4.56-2.74 vs delayed: 4.47-2.74; P=.85), who did not yet have access to the website. A higher baseline DT score was significantly predictive of reduction in DT score during this period (P<.001). Median DT, HADS-Anxiety, and HADS-Depression scores reduced between orchidectomy and 3 weeks postoperatively and then remained stable throughout the observation period. Thematic analysis of 16 semistructured interviews revealed 4 key themes, “Nuts & Bolts is a helpful tool,” “Maximizing benefits of the website,” “Whirlwind of diagnosis and readiness for treatment,” and “Primary stressors and worries,” as well as multiple subthemes. ConclusionsDistress is common following the diagnosis of testicular cancer; however, it decreases over time. Nuts & Bolts was considered useful, acceptable, and relevant by individuals diagnosed with testicular cancer, with strong support for the intervention rendered by thematic analyses of semistructured interviews. The best time to introduce support, such as Nuts & Bolts, is yet to be determined; however, it may be most beneficial as soon as testicular cancer is strongly suspected or diagnosed

    Indazole-6-phenyl­cyclopropyl­carboxylic Acids as Selective GPR120 Agonists with in Vivo Efficacy

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    GPR120 agonists have therapeutic potential for the treatment of diabetes, but few selective agonists have been reported. We identified an indazole-6-phenyl­cyclopropyl­carboxylic acid series of GPR120 agonists and conducted SAR studies to optimize GPR120 potency. Furthermore, we identified a (<i>S</i>,<i>S</i>)-cyclopropyl­carboxylic acid structural motif which gave selectivity against GPR40. Good oral exposure was obtained with some compounds displaying unexpected high CNS penetration. Increased MDCK efflux was utilized to identify compounds such as <b>33</b> with lower CNS penetration, and activity in oral glucose tolerance studies was demonstrated. Differential activity was observed in GPR120 null and wild-type mice indicating that this effect operates through a mechanism involving GPR120 agonism
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