Modelling of an IR scintillation counter

A systematic study of the excitation and de-excitation mechanisms in ternary gas mixtures Ar+CO2+N2 is presented regarding the possibility of developing a proportional scintillation counter based on the detection of the infrared molecular emissions associated with the lowest vibrational states of molecules. The use of visible or near-infrared photons ([lambda]<1 [mu]m) for applications like imaging and quality control of microstructure detectors has been reported. In view of these applications we analyse the processes leading to near-infrared emissions in pure argon and give an estimation of the number of photons emitted per electron, at several pressures, as a function of the charge gain.http://www.sciencedirect.com/science/article/B6TJM-3YXB101-2M/1/b5bfeb3739389bb6dbe4d84c8746dbf

Dissipation and memory effects in pure glue deconfinement

We investigate the effects of dissipation in the deconfining transition for a pure SU(2) gauge theory. Using an effective model for the order parameter, we study its Langevin evolution numerically, and compare results from local additive noise dynamics to those obtained considering an exponential non-local kernel for early times.Comment: 4 pages, 2 figures, to appear in the proceedings of Strong and Electroweak Matter (SEWM06), BNL, May 200

NMR evidence for very slow carrier density fluctuations in the organic metal (TMTSF)2_2ClO4_4

We have investigated the origin of the large increase in spin-echo decay rates for the $^{77}$Se nuclear spins at temperatures near to $T=30K$ in the organic superconductor (TMTSF)$_2$ClO$_4$. The measured angular dependence of $T_2^{-1}$ demonstrates that the source of the spin-echo decays lies with carrier density fluctuations rather than fluctuations in TMTSF molecular orientation. The very long time scales are directly associated with the dynamics of the anion ordering occurring at $T=25K$, and the inhomogeneously broadened spectra at lower temperatures result from finite domain sizes. Our results are similar to observations of line-broadening effects associated with charge-ordering transitions in quasi-two dimensional organic conductors.Comment: 5 pages, 4 figure

Pressure of massless hot scalar theory in the boundary effective theory framework

We use the boundary effective theory (BET) approach to thermal field theory in order to calculate the pressure of a system of massless scalar fields with quartic interaction. The method naturally separates the infrared physics, and is essentially non-perturbative. To lowest order, the main ingredient is the solution of the free Euler-Lagrange equation with non-trivial (time) boundary conditions. We derive a resummed pressure, which is in good agreement with recent calculations found in the literature, following a very direct and compact procedure.Comment: 10 pages, 4 figure

A control framework for a remotely operated vehicle

A control framework enabling the automated maneuvering of a Remotely Operate Vehicle (ROV) is presented. The control architecture is structured according to the principle of composition of vehicle motions from a minimal set of elemental maneuvers that are designed and verified independently. The principled approach is based on distributed hybrid systems techniques, and spans integrated design, simulation and implementation as the same model is used throughout. Hybrid systems control techniques are used to synthesize the elemental maneuvers and to design protocols, which coordinate the execution of elemental maneuvers within a complex maneuver. This work is part of the Inspection of Underwater Structures (IES) project whose main objective is the implementation of a ROV-based system for the inspection of underwater structures

Effective potential in the BET formalism

We calculate the one-loop effective potential at finite temperature for a system of massless scalar fields with quartic interaction $\lambda\phi^4$ in the framework of the boundary effective theory (BET) formalism. The calculation relies on the solution of the classical equation of motion for the field, and Gaussian fluctuations around it. Our result is non-perturbative and differs from the standard one-loop effective potential for field values larger than $T/\sqrt{\lambda}$.Comment: 10 pages, 3 figure

Dilute Nuclear Matter in Chiral Perturbation Theory

We use chiral perturbation theory to compute the effective nucleon propagator in an expansion about low density in the chiral limit. We neglect four-nucleon interactions and focus on pion exchange. Evaluating the nucleon self-energy on its mass shell to leading order, we show that the effective nucleon mass increases by a small amount. We discuss the relevance of our results to the structure of compact stars.Comment: Manuscript rewritten, especially conclusions about mass shifts; contact terms cannot be neglected. Computation unchange

What about vaginal extraction of the kidney? results of an online survey

PURPOSE: We aimed to characterize surgeons opinion about the vaginal extraction of the kidney after transperitoneal laparoscopic nephrectomy. Matherial and Methods: A 9-item questionnaire was published online (Survey Monkey TM) and publicized via email to a multidisciplinary pool of surgeons in Portugal. Data was collected and statistical analysis was performed using IBM SPSS Statistics, Version 21.0. RESULTS: Three hundred and fifty nine inquiries were sent, 154 surgeons completed the questionnaires (response rate of 43.0%). Fifty five point eight percent of the participants would choose the transvaginal approach for themselves or for a close relative. The most stated arguments were a better cosmesis (29.0%) expectancy of lower post operative pain (26.0%) and lower rate of incisional hernias (23.0%). Defenders of the transabdominal procedure justified with an expectancy of lower complication rate (39%), namely impairment of sexual function and fertility (22%). The female gender and the familiarity with transvaginal surgery were the stronger predictors of the option for this approach (70.6% vs 48.5%; p=0,016 and 85.3% vs 46.6%; p <0.001 respectively). CONCLUSIONS: Contrasting with similar surveys published on transvaginal NOTES, the vaginal specimen extraction after conventional laparoscopic nephrectomy was fairly accepted by the inquired surgeons.info:eu-repo/semantics/publishedVersio

From QCD lattice calculations to the equation of state of quark matter

We describe two-flavor QCD lattice data for the pressure at finite temperature and zero chemical potential within a quasiparticle model. Relying only on thermodynamic selfconsistency, the model is extended to nonzero chemical potential. The results agree with lattice calculations in the region of small chemical potential.Comment: 5 eps figure