Biosphere 2 test module experimentation program

The Biosphere 2 Test Module is a facility which has the capability to do either short or long term closures: five month closures with plants were conducted. Also conducted were investigations of specific problems, such as trace gas purification by bioregenerative systems by in-putting a fixed concentration of a gas and observing its uptake over time. In other Test Module experiments, the concentration of one gas was changed to observe what effects this has on other gases present or on the system. The science of biospherics which encompasses the study of closed biological systems provides an opening into the future in space as well as in the Earth's biosphere

Localization Properties of Quantized Magnetostatic Modes in Nanocubes

We investigate the dynamical properties of a system of interacting magnetic dipoles disposed in sites of an sc lattice and forming a cubic-shaped sample of size determined by the cube edge length (N-1)a (a being the lattice constant, N representing the number of dipolar planes). The dipolar field resulting from the dipole-dipole interactions is calculated numerically in points of the axis connecting opposite cube face centers (central axis) by collecting individual contributions to this field coming from each of the N atomic planes perpendicular to the central axis. The applied magnetic field is assumed to be oriented along the central axis, magnetizing uniformly the whole sample, all the dipoles being aligned parallelly in the direction of the applied field. The frequency spectrum of magnetostatic waves propagating in the direction of the applied field is found numerically by solving the Landau-Lifshitz equation of motion including the local (nonhomogeneous) dipolar field component; the mode amplitude spatial distributions (mode profiles) are depicted as well. It is found that only the two energetically highest modes have bulk-extended character. All the remaining modes are of localized nature; more precisely, the modes forming the lower part of the spectrum are localized in the subsurface region, while the upper-spectrum modes are localized around the sample center. We show that the mode localization regions narrow down as the cube size, N, increases (we investigated the range of N=21 to N=101), and in sufficiently large cubes one obtains practically only center-localized and surface-localized magnetostatic modes.Comment: 20 pages, 9 figures in postscript, useing Revtex4.cl

Time Shared Optical Network (TSON): a novel metro architecture for flexible multi-granular services

This paper presents the Time Shared Optical Network (TSON) as metro mesh network architecture for guaranteed, statistically-multiplexed services. TSON proposes a flexible and tunable time-wavelength assignment along with one-way tree-based reservation and node architecture. It delivers guaranteed sub-wavelength and multi-granular network services without wavelength conversion, time-slice interchange and optical buffering. Simulation results demonstrate high network utilization, fast service delivery, and low end-to-end delay on a contention-free sub-wavelength optical transport network. In addition, implementation complexity in terms of Layer 2 aggregation, grooming and optical switching has been evaluated

Strong magnetic fields in nonlocal chiral quark models

We study the behavior of strongly interacting matter under a uniform intense external magnetic field in the context of nonlocal extensions of the Polyakov-Nambu-Jona-Lasinio model. A detailed description of the formalism is presented, considering the cases of zero and finite temperature. In particular, we analyze the effect of the magnetic field on the chiral restoration and deconfinement transitions, which are found to occur at approximately the same critical temperatures. Our results show that these models offer a natural framework to account for the phenomenon of inverse magnetic catalysis found in lattice QCD calculations.Fil: Gomez Dumm, Daniel Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Izzo Villafañe, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Noguera, S.. Universidad de Valencia; EspañaFil: Pagura, Valeria Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Valencia; EspañaFil: Scoccola, Norberto Nerio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad Favaloro; Argentin

Using a TV Set to Show Electron Diffraction

We show the feasibility of constructing a simple set-up to demonstrate the diffraction of electrons starting from a standard TV set. Two concentric rings around a central maxima appears on the screen of the modified TV set corresponding to atomic planes (1, 0, 0) and (1, 1, 0) of a hexagonal structure of graphite sample. A reasonable Planck’s constant value is determined through the slope of a plot of λd2 vs 1/V where we used the average Bragg wavelength for both diffraction rings for each value of accelerating voltage. Since wave particle behavior of matter is shown, we believe this simple set-up is useful for introductory physics courses at high school and undergraduate levels.We show the feasibility of constructing a simple set-up to demonstrate the diffraction of electrons starting from a standard TV set. Two concentric rings around a central maxima appears on the screen of the modified TV set corresponding to atomic planes (1, 0, 0) and (1, 1, 0) of a hexagonal structure of graphite sample. A reasonable Planck’s constant value is determined through the slope of a plot of λd2 vs 1/V where we used the average Bragg wavelength for both diffraction rings for each value of accelerating voltage. Since wave particle behavior of matter is shown, we believe this simple set-up is useful for introductory physics courses at high school and undergraduate levels

Pion distribution amplitude and the pion-photon transition form factor in a nonlocal chiral quark model

We study the pion distribution amplitude (πDA) in the context of a nonlocal chiral quark model. The corresponding Lagrangian reproduces the phenomenological values of the pion mass and decay constant, as well as the momentum dependence of the quark propagator obtained in lattice calculations. It is found that the obtained πDA has two symmetric maxima, which arise from the new contributions generated by the nonlocal character of the interactions. This πDA is applied to leading order and next-to-leading order calculations of the pion-photon transition form factor. Implications of the results are discussed.Instituto de Física La Plat

η-γ and η′-γ transition form factors in a nonlocal NJL model

We study the η and η′ distribution amplitudes (DAs) in the context of a nonlocal SU(3)L - SU(3)R chiral quark model. The corresponding Lagrangian allows us to reproduce the phenomenological values of pseudoscalar meson masses and decay constants, as well as the momentum dependence of the quark propagator arising from lattice calculations. It is found that the obtained DAs have two symmetric maxima, which arise from new contributions generated by the nonlocal character of the interactions. These DAs are then applied to the calculation of the η-γ and η′-γ transition form factors. Implications of our results regarding higher twist corrections and/or contributions to the transition form factors originated by gluon-gluon components in the η and η′ mesons are discussed.Instituto de Física La PlataConsejo Nacional de Investigaciones Científicas y Técnica

Light pseudoscalar meson masses under strong magnetic fields within the SU(3) Nambu-Jona-Lasinio model

We calculate the pole masses of pseudoscalar mesons in a strongly magnetized medium within the framework of the SU(3) Nambu-Jona-Lasinio model, using a magnetic field-independent regularization scheme. We employ both a constant and a magnetic field-dependent coupling G(B), the latter being fitted to reproduce lattice QCD results for the pseudocritical chiral transition temperature. Numerical results for the pole masses are obtained for definite parametrizations of the model. For neutral mesons, the use of G(B) provides closer agreement with lattice QCD results, which reveal a decrease of the mass with the external field. On the contrary, charged mesons masses are enhanced by B, showing no sign of the nonmonotonous behavior found in recent lattice QCD simulations.Fil: Avancini, Sidney S.. Universidade Federal Da Santa Catarina. Cent.de Cs Físicas E Matemáticas; BrasilFil: Sodre, Joanna. Universidade Federal Da Santa Catarina. Cent.de Cs Físicas E Matemáticas; BrasilFil: Coppola, Máximo. Comisión Nacional de Energía Atómica. Gerencia de Área de Investigaciones y Aplicaciones No Nucleares. Gerencia de Física (CAB); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scoccola, Norberto Nerio. Comisión Nacional de Energía Atómica. Gerencia de Área de Investigaciones y Aplicaciones No Nucleares. Gerencia de Física (CAB); Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

O mesmo e o outro: Sartre e a má-fé

A partir da noção de má-fé, o artigo busca traçar as bases para um diagnóstico da contemporaneidade, tendo como índice, por um lado, a falta de determinação humana e, por outro, a efetividade do mundo.

NJL-type models in the presence of intense magnetic fields: The role of the regularization prescription

We study the regularization dependence of the Nambu-Jona-Lasinio model (NJL) predictions for some properties of magnetized quark matter at zero temperature (and baryonic density) in the mean field approximation. The model parameter dependence for each regularization procedure is also analyzed in detail. We calculate the average and difference of the quark condensates using different regularization methods and compare with recent lattice results. In this context, the reliability of the different regularization procedures is discussed.Fil: Avancini, Sidney S.. Universidade Federal Da Santa Catarina. Cent.de Cs Físicas E Matemáticas; BrasilFil: Farias, Ricardo L. S.. Universidade Federal de Santa Maria; BrasilFil: Scoccola, Norberto Nerio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica; Argentina. Universidad Favaloro. Facultad de Ingeniería y Ciencias Exactas y Naturales; ArgentinaFil: Tavares, William R.. Universidade Federal Da Santa Catarina. Cent.de Cs Físicas E Matemáticas; Brasi