2,053 research outputs found

    Particle Ratios as a Probe of the QCD Critical Temperature

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    We show how the measured particle ratios can be used to provide non-trivial information about the critical temperature of the QCD phase transition. This is obtained by including the effects of highly massive Hagedorn resonances on statistical models, which are used to describe hadronic yields. The inclusion of Hagedorn states creates a dependence of the thermal fits on the Hagedorn temperature, THT_H, which is assumed to be equal to TcT_c, and leads to an overall improvement of thermal fits. We find that for Au+Au collisions at RHIC at sNN=200\sqrt{s_{NN}}=200 GeV the best square fit measure, χ2\chi^2, occurs at Tc176T_c \sim 176 MeV and produces a chemical freeze-out temperature of 172.6 MeV and a baryon chemical potential of 39.7 MeV.Comment: 6 pages, 4 figure

    On the dimensional dependence of duality groups for massive p-forms

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    We study the soldering formalism in the context of abelian p-form theories. We develop further the fusion process of massless antisymmetric tensors of different ranks into a massive p-form and establish its duality properties. To illustrate the formalism we consider two situations. First the soldering mass generation mechanism is compared with the Higgs and Julia-Toulouse mechanisms for mass generation due to condensation of electric and magnetic topological defects. We show that the soldering mechanism interpolates between them for even dimensional spacetimes, in this way confirming the Higgs/Julia-Toulouse duality proposed by Quevedo and Trugenberger \cite{QT} a few years ago. Next, soldering is applied to the study of duality group classification of the massive forms. We show a dichotomy controlled by the parity of the operator defining the symplectic structure of the theory and find their explicit actions.Comment: Reference [8] has been properly place

    On duality of the noncommutative extension of the Maxwell-Chern-Simons model

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    We study issues of duality in 3D field theory models over a canonical noncommutative spacetime and obtain the noncommutative extension of the Self-Dual model induced by the Seiberg-Witten map. We apply the dual projection technique to uncover some properties of the noncommutative Maxwell-Chern-Simons theory up to first-order in the noncommutative parameter. A duality between this theory and a model similar to the ordinary self-dual model is estabilished. The correspondence of the basic fields is obtained and the equivalence of algebras and equations of motion are directly verified. We also comment on previous results in this subject.Comment: Revtex, 9 pages, accepted for publication PL

    Evaluating a Transdiagnostic, Mindfulness-Based Cognitive Therapy (MBCT) Group for Service Users Transitioning out of Secondary Mental Health Care Services

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    Background: Traditional Cognitive Behaviour Therapy (CBT) has developed within a disorder-focused paradigm and focuses on altering the specific content of thoughts. However, emerging evidence suggests that there may be a number of cognitive and behavioural processes that are shared across different psychological disorders, and are therefore “transdiagnostic”. It has been further suggested that these processes may themselves share commonalities. Mindfulness-Based Cognitive Therapy (MBCT), is thought to target a core process of "inflexible awareness" and may also target processes of “experiential avoidance” and “control”, which are thought to underlie these transdiagnostic processes. Aims: The current study aimed to evaluate the usefulness of group MBCT within a transdiagnostic population of service users, transitioning out of secondary care services. The study further aimed to investigate the impact of group MBCT on a wide range of cognitive and behavioural processes to understand the transdiagnostic potential of the intervention. A final aim was to explore participants’ experiences of change as a result of the group and to determine which aspects of the group were helpful or unhelpful. Methods: A mixed-methodological, small-N design was employed. Six participants from an inner-city Primary Care Mental Health Service were recruited to take part in the study. Participants attended an 8-week MBCT group facilitated by an experienced mindfulness teacher. Symptom-based, process based and goal-based outcome measures were collected on weekly basis and at one-month follow-up. Five participants subsequently took part in a semistructured qualitative interview to discuss their experiences of the group. Results: Participants reported finding the group useful in moving towards valued outcomes and changes were observed on process-based measures. Participants tended to engage less in cognitive and behavioural trandiagnostic processes and demonstrated increases in flexible awareness and reorganisation of conflict over the course of the group. However, limited changes were observed on symptom-based measures. Participants described therapeutic change as “becoming unbound from distress” and “taking back control”. Participants offered useful insights into valued aspects of the group content, delivery and structure as well as the experience of being with others, and life events outside of the group, which impacted on the group experience. Discussion: There was preliminary evidence that group MBCT was a useful intervention within the present population, and may provide a wider-reaching and more cost-effective alternative to disorder-focused group interventions. The findings also support arguments for a change in theoretical conceptualisations of psychological distress. Furthermore, the lack of observed change on symptom-based measures has wider implications for the types of outcomes used to measure meaningful change within mental health services

    Direct observation of clinical encounters (DOCE) of medical students pre-rounding in the hospital: development of a pilot program and observation checklist

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    Background: Medical educators have opined that clinical, communication, and professionalism skills of medical students are best taught and assessed by faculty directly observing clinical encounters between students and patients. Nonetheless, the medical literature suggests that these direct observations of clinical encounters (DOCE) occur during less than one-quarter of internal medicine clerkships. Lack of faculty time is often cited as a barrier to completing DOCE. Most previously reported DOCE in internal medicine clerkships have involved interviewing, examining and presenting new patients, and averaged 45 minutes to complete and provide feedback to the student. \xa0Purpose: To learn if DOCE conducted during medical student pre-rounding on their hospital patients would be a useful learning exercise for medical students and to assess faculty time involved. Description. From April through October, 2010, third-year medical students were offered the opportunity of a DOCE during their internal medicine clerkship. This exercise was discussed with students during their clerkship orientation, and students were asked to contact directly the supervising faculty member to arrange a date and time. One of two academic hospitalists observed the student making pre-rounds on a patient that they had previously admitted and were following on-service. Faculty used a checklist comprised of 17 different items in three categories: communication (8 items), physical examination (5 items), and professionalism (4 items). After the observation, faculty provided to the student a formative evaluation that did not contribute to the students clerkship grade. Faculty made written comments on the checklist and gave a copy to the student. 31/34 (91%) students completed the DOCE, and records were available for 30 of these encounters. Time of observation averaged 15.3 minutes (range 7 - 25 minutes) and feedback averaged 13.9 minutes (range 8 - 22 minutes). Faculty provided feedback to students in the following areas (proportion of students): communication (30/30, 100%); physical examination (27/30, 90%); professionalism (30/30, 100%). 25/31 (81%) of students completed an anonymous satisfaction survey. 23/25 (92%) of these students found the exercise to be useful or very useful (average 5 point Likert score = 4.56) and 23/25 (92%) found it easy or very easy to schedule (average 5 point Likert score = 4.48).\u2

    Near Zone Navier-Stokes Analysis of Heavy Quark Jet Quenching in an N\mathcal{N} =4 SYM Plasma

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    The near zone energy-momentum tensor of a supersonic heavy quark jet moving through a strongly-coupled N=4\mathcal{N}=4 SYM plasma is analyzed in terms of first-order Navier-Stokes hydrodynamics. It is shown that the hydrodynamical description of the near quark region worsens with increasing quark velocities. For realistic quark velocities, v=0.99v=0.99, the non-hydrodynamical region is located at a narrow band surrounding the quark with a width of approximately 3/πT3/\pi T in the direction parallel to the quark's motion and with a length of roughly 10/πT10/\pi T in the perpendicular direction. Our results can be interpreted as an indication of the presence of coherent Yang-Mills fields where deviation from hydrodynamics is at its maximum. In the region where hydrodynamics does provide a good description of the system's dynamics, the flow velocity is so small that all the nonlinear terms can be dropped. Our results, which are compatible with the thermalization timescales extracted from elliptic flow measurements, suggest that if AdS/CFT provides a good description of the RHIC system, the bulk of the quenched jet energy has more than enough time to locally thermalize and become encoded in the collective flow. The resulting flow pattern close to the quark, however, is shown to be considerably different than the superposition of Mach cones and diffusion wakes observed at large distances.Comment: new revised version, 11 figures, as published in PR
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