1,957 research outputs found

    Cluster Heat Bath Algorithm in Monte Carlo Simulations of Ising Models

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    We have proposed a cluster heat bath method in Monte Carlo simulations of Ising models in which one of the possible spin configurations of a cluster is selected in accordance with its Boltzmann weight. We have argued that the method improves slow relaxation in complex systems and demonstrated it in an axial next-nearest-neighbor Ising(ANNNI) model in two-dimensions.Comment: 10 pages, REVTeX, 2 figures, to appear in Phys.Rev.Let

    Development of deep-sea drone by spherical ultrasonic motor

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    The world ocean occupies 70 % on the earth and the average sea depth is about 4,000 m. More than 80 percent of it has not been investigated precisely and the bottom shape of the sea has not been mapped. When doing resource-searching in the future, the precise maps must be required. So, the authors have developed a drone movable around 4,000 m deep sea to measure the bottom of the ocean. It is based on spheres, which includes cameras, batteries, some sensors and controllers. It can rotate a spherical rotor sensing widely to obtain the information about the bottom of the sea. At the first step of the research, the authors have made basic experiments of the motor’s performance in water. The authors have obtained the excellent results in maneuverability, temperature durability, and shock resistance of the motor

    ORDEM DE HABEAS CORPUS em favor das chimpanzés “LILI” e “MEGH”

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    ORDEM DE HABEAS CORPU

    Confined Phase In The Real Time Formalism And The Fate Of The World Behind The Horizon

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    In the real time formulation of finite temperature field theories, one introduces an additional set of fields (type-2 fields) associated to each field in the original theory (type-1 field). In hep-th/0106112, in the context of the AdS-CFT correspondence, Maldacena interpreted type-2 fields as living on a boundary behind the black hole horizon. However, below the Hawking-Page transition temperature, the thermodynamically preferred configuration is the thermal AdS without a black hole, and hence there are no horizon and boundary behind it. This means that when the dual gauge theory is in confined phase, the type-2 fields cannot be associated with the degrees of freedom behind the black hole horizon. I argue that in this case the role of the type-2 fields is to make up bulk type-2 fields of classical closed string field theory on AdS at finite temperature in the real time formalism.Comment: v2: cases divided into sections with more detailed explanations. considerably enlarged with examples and a lot of figures. sec 4.1.2 for general closed cut-out circuits and appendix A for a sample calculation newly added. many minor corrections and clarifying comments. refs added. v3: refs and related discussion added. 1+46 pages, 26 figures. published versio

    The defect variance of random spherical harmonics

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    The defect of a function f:MRf:M\rightarrow \mathbb{R} is defined as the difference between the measure of the positive and negative regions. In this paper, we begin the analysis of the distribution of defect of random Gaussian spherical harmonics. By an easy argument, the defect is non-trivial only for even degree and the expected value always vanishes. Our principal result is obtaining the asymptotic shape of the defect variance, in the high frequency limit. As other geometric functionals of random eigenfunctions, the defect may be used as a tool to probe the statistical properties of spherical random fields, a topic of great interest for modern Cosmological data analysis.Comment: 19 page

    Measuring our universe from galaxy redshift surveys

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    Galaxy redshift surveys have achieved significant progress over the last couple of decades. Those surveys tell us in the most straightforward way what our local universe looks like. While the galaxy distribution traces the bright side of the universe, detailed quantitative analyses of the data have even revealed the dark side of the universe dominated by non-baryonic dark matter as well as more mysterious dark energy (or Einstein's cosmological constant). We describe several methodologies of using galaxy redshift surveys as cosmological probes, and then summarize the recent results from the existing surveys. Finally we present our views on the future of redshift surveys in the era of Precision Cosmology.Comment: 82 pages, 31 figures, invited review article published in Living Reviews in Relativity, http://www.livingreviews.org/lrr-2004-

    Elucidating the photosynthetic responses in chlorophyll-deficient soybean (Glycine max, L.) leaf

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    Chlorophyll (Chl)-deficient plants can potentially increase global surface albedo of mono-cropping systems, and simultaneously maintain a similar photosynthetic efficiency by increasing light canopy penetration and thus lowering investment in pigments. However, some previous studies have shown that pale mutants might reduce productivity in field conditions. Such lower yields were suspected to be due to loss of photosynthetic efficiency at leaf level during light fluctuations as a consequence of reduced capacity and slower relaxation of non-photochemical quenching (NPQ) of Chl fluorescence. In this paper, we tested this hypothesis by comparing, CO2 assimilation (A), photosystem II (PSII) efficiency (ΦPSII), photochemical quenching and NPQ, electron transport rate (ETR) and fluorescence yield (Fyield) in a green soybean (Glycine max L.) cultivar (Eiko) and in a Chl-deficient (MinnGold) mutant under dynamically fluctuating light conditions. MinnGold had significantly slower induction of ETR and lower A and ETR than Eiko, but there was little difference in ΦPSII between the two genotypes, suggesting that the lower photosynthesis of MinnGold was mainly due to lower light energy absorption by a Chl-deficient leaf. The NPQ capacity was also smaller in MinnGold than in Eiko. As for the kinetics of the rapidly inducible component of NPQ, MinnGold showed slower induction, not relaxation, than Eiko. The combination of the effect of Chl-deficiency on lower photosynthesis, NPQ capacity and slower NPQ induction may explain the lower biomass accumulation of MinnGold in the field. Our physiological observations, combined with fluorescence kinetics, can serve as a basis to parameterize Chl content in modelling radiative transfer and photosynthesis for upscaling measures of plant and ecosystem productivity by a big leaf model

    Cosmological Redshift Distortion of Correlation Functions as a Probe of the Density Parameter and the Cosmological Constant

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    We propose cosmological redshift-space distortion of correlation functions of galaxies and quasars as a probe of both the density parameter Ω0\Omega_0 and the cosmological constant λ0\lambda_0. In particular, we show that redshift-space distortion of quasar correlation functions at z2z\sim2 can in principle set a constraint on the value of λ0\lambda_0. This is in contrast to the popular analysis of galaxy correlation functions in redshift space which basically determines Ω00.6/b\Omega_0^{0.6}/b, where bb is the bias parameter, but is insensitive to λ0\lambda_0. For specific applications, we present redshift-space distortion of correlation functions both in cold dark matter models and in power-law correlation function models, and discuss the extent to which one can discriminate between the different λ0\lambda_0 models.Comment: 9 pages, 3 figures included. Accepted for Publication in ApJ Letter
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