30,369 research outputs found

    A Random Multifractal Tilling

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    We develop a multifractal random tilling that fills the square. The multifractal is formed by an arrangement of rectangular blocks of different sizes, areas and number of neighbors. The overall feature of the tilling is an heterogeneous and anisotropic random self-affine object. The multifractal is constructed by an algorithm that makes successive sections of the square. At each nn-step there is a random choice of a parameter ρi\rho_i related to the section ratio. For the case of random choice between ρ1\rho_1 and ρ2\rho_2 we find analytically the full spectrum of fractal dimensions

    Non-Collinear Ferromagnetic Luttinger Liquids

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    The presence of electron-electron interactions in one dimension profoundly changes the properties of a system. The separation of charge and spin degrees of freedom is just one example. We consider what happens when a system consisting of a ferromagnetic region of non-collinearity, i.e. a domain wall, is coupled to interacting electrons in one-dimension (more specifically a Luttinger liquid). The ferromagnetism breaks spin charge separation and the presence of the domain wall introduces a spin dependent scatterer into the problem. The absence of spin charge separation and the effects of the electron correlations results in very different behaviour for the excitations in the system and for spin-transfer-torque effects in this model.Comment: 6 pages, submitted to Journal of Physics: Conference Series for JEMS 201

    Preliminary analysis of the competitiveness determinants in wine industry in the São Francisco Valley, Brazil.

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    In the current contemporary world scene, the science, technology and innovation are key elements for economic and social growth and democratization of opportunities of a nation. The Brazilian wine sector, especially the Sao Francisco Valley, has been increasing its role as agent in regional development and national agribusiness which, despite the challenges of typicality and uniqueness of the tropical viticulture practiced in the region, combined with increasing competition in their markets, also plays an important role by reducing social and economic inequality between the regions of Brazil

    All-sky Relative Opacity Mapping Using Night Time Panoramic Images

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    An all-sky cloud monitoring system that generates relative opacity maps over many of the world's premier astronomical observatories is described. Photometric measurements of numerous background stars are combined with simultaneous sky brightness measurements to differentiate thin clouds from sky glow sources such as air glow and zodiacal light. The system takes a continuous pipeline of all-sky images, and compares them to canonical images taken on other nights at the same sidereal time. Data interpolation then yields transmission maps covering almost the entire sky. An implementation of this system is currently operating through the Night Sky Live network of CONCAM3s located at Cerro Pachon (Chile), Mauna Kea (Hawaii), Haleakala (Hawaii), SALT (South Africa) and the Canary Islands (Northwestern Africa).Comment: Accepted for publication in PAS

    A concept for the viticulture of 'tropical wines'.

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    At worldwide level, the classical viticulture produces wines is almost all places in different climate types, where it is possible to obtain only one harvest per year. In these conditions, bud burst in vines occurs as a result of temperature raising at the end of the winter?beginning of spring. With the development of the vegetative cycle, grapes arrive to maturity/harvest period at the end of the summer?beginning of the fall season. After the fall of the leaves, vines undergo a dormant period with a vegetative repose (condition found also in some intertropical producer regions). A lot of grapes are produced for a long-time in the intertropical zone, but only a little part is used to winemaking. Considered a challenge in the past, to produce quality wines in the tropics became reality. The present industry of fine wines began about 30 years ago. Today, there are many commercial wineries in several countries in Occident and Orient in the tropical zone of the globe, like in Brazil, India, Thailand and Venezuela, producing some million liters of fine wines per year - called ?tropical wines?. This article analysis these climates, in relation to the particular viticulture adapted and developed, where it is possible to have more than one cycle per year, with one or more harvests per year. Based on the particularities of this viticulture, a characterization is proposed for the viticulture of ?tropical wines?. Some examples showing different tropical climates are presented

    The development of the viticulture for a high quality tropical wine production in the world.

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    A lot of grapes are produced in the tropics, but only a little part is used to winemaking, what represents some million liters of tropical wines produced per year. The present industry of tropical wine production began 30 years ago. Today, there are many commercial wineries in several countries in the tropical zone of the globe, like in Brazil, India, Thailand and Venezuela. Considered a challenge in the past, producing quality wines in the tropics became reality. This article analyses the tropical viticulture for wine production, where grapevines are constantly growing. The concept of tropical viticultural climate, main characteristics and production systems in tropical zones are presented. Considering that almost everything is new in terms of viticulture science and technology, the main lacks of know-how are analyzed. The concept of "just-in-tirne quality" for some tropical wines is also presented. Our analysis indicates that it is possible to predict, for the near future, the achievement of a high quality production of tropical wines with expressive amount, despite marketing challenges and competi tive opportunities in the global market

    A Herschel Study of 24 micron-Selected AGNs and Their Host Galaxies

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    We present a sample of 290 24-micron-selected active galactic nuclei (AGNs) mostly at z ~ 0.3 -- 2.5, within 5.2 square degrees distributed as 25' X 25' fields around each of 30 galaxy clusters in the Local Cluster Substructure Survey (LoCuSS). The sample is nearly complete to 1 mJy at 24 microns, and has a rich multi-wavelength set of ancillary data; 162 are detected by Herschel. We use spectral templates for AGNs, stellar populations, and infrared emission by star forming galaxies to decompose the spectral energy distributions (SEDs) of these AGNs and their host galaxies, and estimate their star formation rates (SFRs), AGN luminosities, and host galaxy stellar masses. The set of templates is relatively simple: a standard Type-1 quasar template; another for the photospheric output of the stellar population; and a far infrared star-forming template. For the Type-2 AGN SEDs, we substitute templates including internal obscuration, and some Type-1 objects require a warm component (T > 50 K). The individually Herschel- detected Type-1 AGNs and a subset of 17 Type-2 ones typically have luminosities > 10^{45} ergs/s, and supermassive black holes of ~ 3 X 10^8 Msun emitting at ~ 10% of the Eddington rate. We find them in about twice the numbers of AGN identified in SDSS data in the same fields, i.e., they represent typical high luminosity AGN, not an infrared-selected minority. These AGNs and their host galaxies are studied further in an accompanying paper
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