15 research outputs found

    PATRIMÔNIO GEOMORFOLÓGICO EM UNIDADES DE CONSERVAÇÃO: ANÁLISE PRELIMINAR DO “MORRO DO CHAPÉU”, PRUDENTÓPOLIS-PR

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    O Patrimônio Geomorfológico refere-se às formas de relevo que possuem determinado valor científico, didático, cultural, ecológico ou econômico, podendo ser considerado como um dos componentes da geodiversidade, que se refere à diversidade natural abiótica da superfície terrestre. O presente trabalho pretende fazer uma análise do geomorfossítio Morro do Chapéu, localizado em Prudentópolis (PR) propondo sua inserção na categoria Monumento Natural do Sistema Nacional de Unidades de Conservação

    Properties of Graphene: A Theoretical Perspective

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    In this review, we provide an in-depth description of the physics of monolayer and bilayer graphene from a theorist's perspective. We discuss the physical properties of graphene in an external magnetic field, reflecting the chiral nature of the quasiparticles near the Dirac point with a Landau level at zero energy. We address the unique integer quantum Hall effects, the role of electron correlations, and the recent observation of the fractional quantum Hall effect in the monolayer graphene. The quantum Hall effect in bilayer graphene is fundamentally different from that of a monolayer, reflecting the unique band structure of this system. The theory of transport in the absence of an external magnetic field is discussed in detail, along with the role of disorder studied in various theoretical models. We highlight the differences and similarities between monolayer and bilayer graphene, and focus on thermodynamic properties such as the compressibility, the plasmon spectra, the weak localization correction, quantum Hall effect, and optical properties. Confinement of electrons in graphene is nontrivial due to Klein tunneling. We review various theoretical and experimental studies of quantum confined structures made from graphene. The band structure of graphene nanoribbons and the role of the sublattice symmetry, edge geometry and the size of the nanoribbon on the electronic and magnetic properties are very active areas of research, and a detailed review of these topics is presented. Also, the effects of substrate interactions, adsorbed atoms, lattice defects and doping on the band structure of finite-sized graphene systems are discussed. We also include a brief description of graphane -- gapped material obtained from graphene by attaching hydrogen atoms to each carbon atom in the lattice.Comment: 189 pages. submitted in Advances in Physic

    Sensitivity of the Cherenkov Telescope Array to a dark matter signal from the Galactic centre

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    We provide an updated assessment of the power of the Cherenkov Telescope Array (CTA) to search for thermally produced dark matter at the TeV scale, via the associated gamma-ray signal from pair-annihilating dark matter particles in the region around the Galactic centre. We find that CTA will open a new window of discovery potential, significantly extending the range of robustly testable models given a standard cuspy profile of the dark matter density distribution. Importantly, even for a cored profile, the projected sensitivity of CTA will be sufficient to probe various well-motivated models of thermally produced dark matter at the TeV scale. This is due to CTA's unprecedented sensitivity, angular and energy resolutions, and the planned observational strategy. The survey of the inner Galaxy will cover a much larger region than corresponding previous observational campaigns with imaging atmospheric Cherenkov telescopes. CTA will map with unprecedented precision the large-scale diffuse emission in high-energy gamma rays, constituting a background for dark matter searches for which we adopt state-of-the-art models based on current data. Throughout our analysis, we use up-to-date event reconstruction Monte Carlo tools developed by the CTA consortium, and pay special attention to quantifying the level of instrumental systematic uncertainties, as well as background template systematic errors, required to probe thermally produced dark matter at these energies

    Mapeamento das formacoes superficiais da Regiao de Sao Pedro- Piracicaba (SP, Brasil).

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    As criteria in photointerpretation slope features, tonality, texture, structure, vegetation density and gullies were utilized. The origin of the surficial formations is related to the weathering, erosion and deposition processes and little diagenesis.-after English summar

    O processo erosivo na Bacia do Alto Paraguai

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    O Pantanal Matogrossense pode ser subdividido nas províncias fisiográficas de Planaltos, Pantanais e Morrarias, com feições geológicas, geomorfológicas, hidrológicas e pedológicas distintas. Nos Planaltos, grandes extensões de florestas e cerrado sofreram desflorestamento e foram substituídas por atividades agropecuárias, a partir dos anos 70. Como conseqüência, o processo erosivo sofreu uma grande aceleração, levando à perda de grandes porções de terras produtivas e assoreamentos na bacia do Pantanal. O objetivo deste trabalho é avaliar as modificações do uso e ocupação do solo nos últimos trinta anos e suas conseqüências no processo erosivo da região. A análise foi feita em três diferentes momentos: 1966, 1985 e 1996, fazendo-se uso de imagens de satélite TM 5 e de cartas topográficas do IBGE em escala 1: 250.000. Quatro áreas-piloto foram selecionadas para estudos mais detalhados: bacia do rio Taquarizinho, na parte leste da área; região de Pedro Gomes, nas proximidades da divisa dos estados de Mato Grosso e Mato Grosso do Sul; bacias do rios Arica-Açu e Arica-Mirim, na parte norte da bacia e a Chapada do rio Correntes/ Itiquira. Nas três primeiras áreas, foi feito o cálculo de perdas de solos por erosão laminar através do emprego da Equação Universal de Perdas de Solo, em ambiente SIG. Os resultados obtidos colocam em evidência a dinâmica ambiental ocorrida na região, nos últimos trinta anos. THE EROSION PROCESS ON ALTO PARAGUAI WATERSHED Abstract The Pantanal Matogrossense can be subdivided into three physiographic provinces, Planaltos, Pantanais and Morrarias, characterized by peculiar geologic, geomorphologic, hydrologic and pedologic features. On the Planaltos province, large extensions of florestas and cerrados, have been submitted to deforestation and were replaced by farming and cattle raising activities from the 70´s years. In the process of transformation, the deforestation is normally done by burnt or extracted trees with the use of weight agricultural machines. As a consequence of that activity, the erosive process suffered a great acceleration, taking to loss portions of productive lands and flooding of low areas in the Pantanal basin (figure 1). The aim of the present paper is to evaluate the changes on the use and occupation of the soil in the last thirty years and theirs consequences on the erosive process of the region. It has been analyzed in three different moments : 1966, 1985 and 1996 (figures 2 and 5). Statistical analysis of multitemporal data base were carried out to compare the land cover changes in these provinces. The 66´s data was available from the DSG/IBGE (Geographic Division of Brazilian Army and Brazilian Institute for Geography and Statistics); the 1985 and 1996 data have been obtained from Landsat TM images interpretation. Four pilot areas were chosen for detailed study: the Taquarizinho basin, located southern from Coxim (figure 6 and tables 1, 2 and 3), the Arica-Açu and Arica-Mirim basins (figures 7 and 8), on the northern part of Alto Paraguai Basin, the Pedro Gomes region (figures 9 and 10 and table 4) and the rio Correntes / Itiquira Chapada (figures 11, 12 and 13). The laminar erosion on the first three areas was calculated with the application of the Universal Soil Loss Equation, aided by Geographic Information System and Remote Sensing techniques. The results obtained put in evidence the environmental dynamic occurred on the Pantanal region in the last thirty years

    Intensity interferometry with the MAGIC telescopes

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    Due to their large mirror size, fast response to single photons, sensitivity and telescope baselines in the order of 100 m, Imaging Atmospheric Cherenkov Telescopes are ideally suited to perform intensity interferometry observations. In 2019 a test readout setup was installed in the two 17-m diameter MAGIC telescopes to allow performing interferometry measurements with them. The first on-sky measurements were able to detect correlated intensity fluctuations consistent with the stellar diameters of three different stars: Adhara (∊ CMa), Benetnasch (η UMa) and Mirzam (β CMa). After the upgrade of the setup in 2021, MAGIC is now equipped with a high-duty-cycle intensity interferometer, already in operation. A technical description of the interferometer and first performance results obtained by measuring several known stellar diameter are presented
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