Protocolo de avaliação da qualidade física e química de cebola.

Neste protocolo, são relatadas as informações necessárias para a avaliação da qualidade química e física em cebola, baseadas em adaptações e modificações realizadas no laboratório de pós-colheita da Embrapa Hortaliaças.bitstream/item/72191/1/cot-831.pd

Casimir Effect Nearby and Through a Cosmological Wormhole

In this letter, we investigate the changes in the quantum vacuum energy density of a massless scalar field inside a Casimir cavity that orbits a wormhole, by considering the cosmological model with an isotropic form of the Morris-Thorne wormhole, embedded in the FLRW universe. In this sense, we examine the effects of its global curvature and scale factor in an instant of the cosmic history, besides the influences of the local geometry as well as of inertial forces, on the Casimirenergy density. We also study the behavior of this quantity when each plate is fixed without rotation at the opposite sides of the wormhole throat, at zero and finite temperatures, taking into account the effective distance between the plates through the wormhole throat.Comment: 11 pages, 2 figure

Muon Detection of TeV Gamma Rays from Gamma Ray Bursts

Because of the limited size of the satellite-borne instruments, it has not been possible to observe the flux of gamma ray bursts (GRB) beyond GeV energy. We here show that it is possible to detect the GRB radiation of TeV energy and above, by detecting the muon secondaries produced when the gamma rays shower in the Earth's atmosphere. Observation is made possible by the recent commissioning of underground detectors (AMANDA, the Lake Baikal detector and MILAGRO) which combine a low muon threshold of a few hundred GeV or less, with a large effective area of 10^3 m^2 or more. Observations will not only provide new insights in the origin and characteristics of GRB, they also provide quantitative information on the diffuse infrared background.Comment: Revtex, 12 pages, 3 postscript figures, uses epsfig.st

Casimir-Yang-Mills wormholes in D=2+1D=2+1

This study presents new three-dimensional traversable wormhole solutions sourced by the Casimir density and pressure related to the quantum vacuum fluctuations in Yang-Mills theory. First, we analyze the noninteracting Casimir effect with an arbitrary state parameter $\omega$ and determine a simple constant wormhole shape function. We introduce a new methodology for deforming the state parameter and find well-behaved redshift functions. The wormhole can be interpreted as a legitimate Casimir wormhole with an expected average state parameter of $\omega=2$. Then, we investigate the curvature properties, energy conditions, and stability of the wormholes, finding that they are stable only if the radius exceeds a specific value near the throat. Furthermore, we discover a new family of traversable wormhole solutions sourced by the quantum vacuum fluctuations of interacting (confined) Yang-Mills fields with a more complex shape function. Deforming the effective state parameter similarly, we obtain well-behaved redshift functions and wormhole solutions that depend on relevant parameters of the system. Notably, higher string tension results in a larger throat radius, potentially driven by an attempt to deconfine gluons and stretch the wormhole.Comment: 20 pages, 8 figure

Clocked Atom Delivery to a Photonic Crystal Waveguide

Experiments and numerical simulations are described that develop quantitative understanding of atomic motion near the surfaces of nanoscopic photonic crystal waveguides (PCWs). Ultracold atoms are delivered from a moving optical lattice into the PCW. Synchronous with the moving lattice, transmission spectra for a guided-mode probe field are recorded as functions of lattice transport time and frequency detuning of the probe beam. By way of measurements such as these, we have been able to validate quantitatively our numerical simulations, which are based upon detailed understanding of atomic trajectories that pass around and through nanoscopic regions of the PCW under the influence of optical and surface forces. The resolution for mapping atomic motion is roughly 50 nm in space and 100 ns in time. By introducing auxiliary guided mode (GM) fields that provide spatially varying AC-Stark shifts, we have, to some degree, begun to control atomic trajectories, such as to enhance the flux into to the central vacuum gap of the PCW at predetermined times and with known AC-Stark shifts. Applications of these capabilities include enabling high fractional filling of optical trap sites within PCWs, calibration of optical fields within PCWs, and utilization of the time-dependent, optically dense atomic medium for novel nonlinear optical experiments

Caracterização fisica e química de abóbora Cucurbita ficifolia Bouché cultivada em Brasília-DF: uma potencial hortaliça para tratamento da diabetes mellitus tipo 2.

Objetivou-se caracterizar química e fisicamente, a espécie domesticada de abóbora C. ficifolia Bouché cultivada em Brasília-DF, uma vez que há relatos na literatura quanto seu potencial efeito hipoglicemiante na diabetes mellitus tipo 2

Superradiance for atoms trapped along a photonic crystal waveguide

We report observations of superradiance for atoms trapped in the near field of a photonic crystal waveguide (PCW). By fabricating the PCW with a band edge near the D$_1$ transition of atomic cesium, strong interaction is achieved between trapped atoms and guided-mode photons. Following short-pulse excitation, we record the decay of guided-mode emission and find a superradiant emission rate scaling as $\bar{\Gamma}_{\rm SR}\propto\bar{N}\cdot\Gamma_{\rm 1D}$ for average atom number $0.19 \lesssim \bar{N} \lesssim 2.6$ atoms, where $\Gamma_{\rm 1D}/\Gamma_0 =1.1\pm0.1$ is the peak single-atom radiative decay rate into the PCW guided mode and $\Gamma_{0}$ is the Einstein-$A$ coefficient for free space. These advances provide new tools for investigations of photon-mediated atom-atom interactions in the many-body regime.Comment: 11 pages, 10 figure

Protocolo de análise para determinação da atividade antioxidante total em hortaliças no sistema beta-caroteno / ácido linoléico.

bitstream/CNPH-2010/36126/1/cot-68.pd