Particle Ratios as a Probe of the QCD Critical Temperature

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, $T_H$, which is assumed to be equal to $T_c$, and leads to an overall improvement of thermal fits. We find that for Au+Au collisions at RHIC at $\sqrt{s_{NN}}=200$ GeV the best square fit measure, $\chi^2$, occurs at $T_c \sim 176$ 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

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

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

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

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

The near zone energy-momentum tensor of a supersonic heavy quark jet moving through a strongly-coupled $\mathcal{N}=4$ 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, $v=0.99$, the non-hydrodynamical region is located at a narrow band surrounding the quark with a width of approximately $3/\pi T$ in the direction parallel to the quark's motion and with a length of roughly $10/\pi T$ 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

Universal Flow-Driven Conical Emission in Ultrarelativistic Heavy-Ion Collisions

The double-peak structure observed in soft-hard hadron correlations is commonly interpreted as a signature for a Mach cone generated by a supersonic jet interacting with the hot and dense medium created in ultrarelativistic heavy-ion collisions. We show that it can also arise due to averaging over many jet events in a transversally expanding background. We find that the jet-induced away-side yield does not depend on the details of the energy-momentum deposition in the plasma, the jet velocity, or the system size. Our claim can be experimentally tested by comparing soft-hard correlations induced by heavy-flavor jets with those generated by light-flavor jets.Comment: 4 pages, 3 figure

Agrobiodiversidade como base para sistemas agrícolas sustentáveis para a agricultura familiar.

bitstream/item/78746/1/Documento-354.pd