On dispersion and characteristic motions of temperature rate dependent materials

Three dimensional theory of thermomechanical material developed using techniques of continuum mechanics and law of thermodynamic

Magnetic field induced singlet - triplet phase transition in quasi one-dimensional organic superconductors

We propose a theoretical model of quasi-one-dimensional superconductors, with attractive electron-electron interactions dominant in the singlet d-wave channel and sub-dominant in the p-wave channel. We discuss, in the mean field approximation, the effect of a magnetic field applied perpendicularly to the direction of the lowest conductivity. The lowest free energy phase corresponds to a singlet d-wave symmetry in low fields, but to a triplet symmetry in high fields. A first order singlet-triplet phase transition is expected at moderate applied fields of a few teslas. We propose to ascribe the recent critical field and NMR experimental data, observed in superconducting (TMTSF)2ClO4 to such an effect.Comment: 6 pages, 2 figures, accepted in EP

Applicability of Modified Effective-Range Theory to positron-atom and positron-molecule scattering

We analyze low-energy scattering of positrons on Ar atoms and N2 molecules using Modified Effective-Range Theory (MERT) developped by O'Malley, Spruch and Rosenberg [Journal of Math. Phys. 2, 491 (1961)]. We use formulation of MERT based on exact solutions of Schroedinger equation with polarization potential rather than low-energy expansions of phase shifts into momentum series. We show that MERT describes well experimental data, provided that effective-range expansion is performed both for s- and p-wave scattering, which dominate in the considered regime of positron energies (0.4 - 2 eV). We estimate the values of the s-wave scattering lenght and the effective range for e+ - Ar and e+ - N2 collisions.Comment: RevTeX, 4 pages, 2 figure

Fine sediment deposits in gravel bed rivers: sensitivity analysis to particle properties using a 2D hydrodynamic and sediment model

Hydrodynamic

Efeito do enxofre, aplicado na forma de gesso, sobre a produção e qualidade do capim colonião (Panicum maximum Jacq.)

Foram conduzidos em vasos com terra em casa de vegetação, ensaios com doses crescentes de enxofre na forma de gesso e nitrogênio em esquema fatorial com repetições em capim Colonião visando verificar o comportamento da gramínea em relação a produção e qualidade.Resumo

Tricritical behaviour in deterministic aperiodic Ising systems

We use a mixed-spin model, with aperiodic ferromagnetic exchange interactions and crystalline fields, to investigate the effects of deterministic geometric fluctuations on first-order transitions and tricritical phenomena. The interactions and the crystal field parameters are distributed according to some two-letter substitution rules. From a Migdal-Kadanoff real-space renormalization-group calculation, which turns out to be exact on a suitable hierarchical lattice, we show that the effects of aperiodicity are qualitatively similar for tricritical and simple critical behaviour. In particular, the fixed point associated with tricritical behaviour becomes fully unstable beyond a certain threshold dimension (which depends on the aperiodicity), and is replaced by a two-cycle that controls a weakened and temperature-depressed tricritical singularity.Comment: Formatting improved. 7 pages, 2 figures (included). Journal reference adde

Injection of photoelectrons into dense argon gas

The injection of photoelectrons in a gaseous or liquid sample is a widespread technique to produce a cold plasma in a weakly--ionized system in order to study the transport properties of electrons in a dense gas or liquid. We report here the experimental results of photoelectron injection into dense argon gas at the temperatureT=142.6 K as a function of the externally applied electric field and gas density. We show that the experimental data can be interpreted in terms of the so called Young-Bradbury model only if multiple scattering effects due to the dense environment are taken into account when computing the scattering properties and the energetics of the electrons.Comment: 18 pages, 10 figures, figure nr. 10 has been redrawn, to be submitted to Plasma Sources Science and Technolog

Induction Chemotherapy Followed by Concurrent Chemoradiation Therapy Versus Concurrent Chemoradiation Therapy Upfront in Locally Advanced Oral Cavity Cancer: Systematic Review and Meta-Analysis of Individual Data

Univ Sao Paulo, Hosp Siriolibanes, Dept Radiat Oncol, Sao Paulo, BrazilUniv Sao Paulo, Fac Med, Inst Canc Estado Sao Paulo, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med UNIFESP EPM, Brazilian Cochrane Ctr, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med UNIFESP EPM, Discipline Emergency Med & Evidence Based Med, Sao Paulo, BrazilHarvard Univ, Sch Med, Dana Farber Canc Inst, Dept Med Oncol, 44 Binney St, Boston, MA 02115 USABrigham & Womens Hosp, Dept Med, 75 Francis St, Boston, MA 02115 USAUniv Calif San Diego, La Jolla, CA 92093 USAHarvard Univ, Sch Med, Dana Farber Canc Inst, Head & Neck Oncol Program, 44 Binney St, Boston, MA 02115 USAAC Camargo Canc Ctr, Dept Head & Neck Surg & Otorhinolaryngol, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med UNIFESP EPM, Brazilian Cochrane Ctr, Sao Paulo, BrazilUniv Fed Sao Paulo, Escola Paulista Med UNIFESP EPM, Discipline Emergency Med & Evidence Based Med, Sao Paulo, BrazilWeb of Scienc

Measure of the film from the declination circle with a lineal array of photosensors (Reticon)

The semi-automatic measure of the photographic film from the declination circle, is based in the use of a lineal array of 512 photosensors, RETICON RL 512G. The corresponding hardware includes analog-digital conversor, a memory of 2 kb RAM, the electronic sinchronization and the necessary interface to control the system with a micro-computer Apple IIe. Lately, the information obtained, is sent to a PC Multitech, which process the data and gives the final results. Four reading, lasting 20 ms in total, are made for each picture: the error of a measure is ±0.02". The system does not need refrigeration.Asociación Argentina de Astronomí