196 research outputs found

    A FREE BOUNDARY ISOPERIMETRIC PROBLEM IN HYPERBOLIC 3-SPACE BETWEEN PARALLEL HOROSPHERES

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    We investigate the isoperimetric problem of finding the regions of prescribed volume with minimal boundary area between two parallel horospheres in hyperbolic 3-space (the part of the boundary contained in the horospheres is not included). We reduce the problem to the study of rotationally invariant regions and obtain the possible isoperimetric solutions by studying the behavior of the profile curves of the rotational surfaces with constant mean curvature in hyperbolic 3-space. We also classify all the connected compact rotational surfaces M of constant mean curvature that are contained in the region between two horospheres, have boundary partial derivative M either empty or lying on the horospheres, and meet the horospheres perpendicularly along their boundary.244112

    Design of a collaborative virtual environment for training security agents in big events

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    This paper describes a design of a collaborative virtual environment (CVE) for training security agents in big events. The CVE was modelled with Autodesk 3ds Max, while Unity 3D was used to create the terrain and implement the features that make up a virtual environment. The Brazilian soccer stadium known as Maracana˜ and its surroundings were chosen as the real counterparts of the CVE. The usability of the CVE was evaluated through simulations involving security agents dealing with threats related to suspects carrying radioactive material in big events. In order to perform these simulations, we use the same procedures used during 2014 FIFA World Cup and planned to be used in Rio 2016 Olympic Games. The main objective of this work is to verify the feasibility of designing a CVE and its usability for training security agents involved in big events issues. Results indicated that the proposed CVE has been successful concerning both, design and usability, besides of helping to improve the ability of each member of the security team on performing his duty

    Theoretical and experimental study on electron interactions with chlorobenzene: Shape resonances and differential cross sections

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    In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7 degrees to 110 degrees. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene. Published by AIP Publishing

    ENSINO E PESQUISA NA LICENCIATURA EM PEDAGOGIA A DISTÂNCIA: POSSIBILIDADES DE COMPREENDER AS INFÂNCIAS NO DIÁLOGO POLO PRESENCIAL E ESCOLA BÁSICA

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    Neste trabalho será abordado o resultado parcial da pesquisa de um grupo de estudo formado por professores (as) e alunos (as) que buscam compreender as crianças pequenas em suas vivências, suas culturas, seus processos de socialização, suas subjetividades, como produzem saberes e conhecimentos, e a qualidade de suas experiências cotidianas.Nossos estudos têm como referência principal as obras de Vigotski, no contexto investigativo e desafiador do cotidiano das crianças (creche e pré-escola), passando pelo conhecimento científico na dimensão sócio histórica, e promovendo o aprendizado, que é a base para o desenvolvimento da criança.Os resultados demonstram a possibilidade de se fazer pesquisa na graduação a distância, integrando o curso de pedagogia ao cotidiano da educação básica, crucial para a construção de conhecimento sobre infância e práticas pedagógicas

    Firing temperature determination and thermoluminescence dating of a brick with cuneiform characters found in the ruins of Ancient Babylon

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    Este artigo tem por objetivo estudar um tijolo com inscrições em caracteres cuneiformes cujas sentenças estão praticamente completas. Estudos tipológicos correspondentes aos relatos históricos sugerem que o tijolo foi manufaturado no século VI a.C., durante a dinastia de Nabucodonosor II, grande monarca da Babilônia. A amostra foi estudada através da difração de raios X (DRX), ressonância paramagnética de elétron (RPE), termoluminescência (TL) e técnicas de análise por ativação instrumental com nêutrons (AAIN). Os resultados demonstraram que o tijolo tem 2350 anos de idade (± 40) e queima menor que 400o C.This paper aims to study a brick with inscriptions in cuneiform characters in  which the sentences are almost complete. Typological studies in agreement with historical records suggest that the tablet was manufactured in the 6th century  BCE during the dynasty of Nebuchadnezzar II, Great King of Babylon. The  sample was studied by X-ray diffraction analysis (XRD), electron paramagnetic resonance (EPR), thermoluminescence (TL), and instrumental neutron activation analysis (INAA) techniques. The results showed that the brick is 2350 years old (± 40) and its firing temperature was lower than 400 °C

    RG108 increases NANOG and OCT4 in bone marrow-derived mesenchymal cells through global changes in DNA modifications and epigenetic activation. RG108 increases NANOG and OCT4 through epigenetic activation.

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    Human bone marrow-derived mesenchymal stem cells (hBMSCs) are important for tissue regeneration but their epigenetic regulation is not well understood. Here we investigate the ability of a non-nucleoside DNA methylation inhibitor, RG108 to induce epigenetic changes at both global and gene-specific levels in order to enhance mesenchymal cell markers, in hBMSCs. hBMSCs were treated with complete culture medium, 50 μM RG108 and DMSO for three days and subjected to viability and apoptosis assays, global and gene-specific methylation/hydroxymethylation, transcript levels' analysis of epigenetic machinery enzymes and multipotency markers, protein activities of DNMTs and TETs, immunofluorescence staining and western blot analysis for NANOG and OCT4 and flow cytometry for CD105. The RG108, when used at 50 μM, did not affect the viability, apoptosis and proliferation rates of hBMSCs or hydroxymethylation global levels while leading to 75% decrease in DNMTs activity and 42% loss of global DNA methylation levels. In addition, DNMT1 was significantly downregulated while TET1 was upregulated, potentially contributing to the substantial loss of methylation observed. Most importantly, the mesenchymal cell markers CD105, NANOG and OCT4 were upregulated being NANOG and OCT4 epigenetically modulated by RG108, at their gene promoters. We propose that RG108 could be used for epigenetic modulation, promoting epigenetic activation of NANOG and OCT4, without affecting the viability of hBMSCs. DMSO can be considered a modulator of epigenetic machinery enzymes, although with milder effect compared to RG108

    THE USE OF VIRTUAL REALITY FOR TRAINING PROFESSIONALS OF NUCLEAR MEDICINE

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    The use of virtual reality has becoming an important tool for training purposes, with emphasis to those procedures that involve risk to professionals, as those associated with occupational exposure to ionizing radiation in nuclear medicine services. According to the basic safety standards (BSS), published by International Atomic Energy Agency (IAEA), the qualification and training of all personnel of a nuclear medicine service should be performed periodically in order to ensure its understanding and better performance of their respective duties. In face of that, this work consists in research, analysis and unification of requirements and specifications for the radiological protection of nuclear medicine workers, specifically those of radiopharmacy. To this end, a detailed study of the radiological safety and workflow related to radiopharmacy procedures is under development considering the radiological recommendations and safety standards of nuclear medicine services. As a result, it is expected a set of information that will enable the development of a virtual training environment in radiological protection for such professionals aiming the development of skills and the improvement of competencies by means of the simulation with lower cost, unlimited number of repetitions of training, without interference in the laboratory routine and the primary purpose of this work: in safe conditions

    Amphibians of Santa Teresa, Brazil: The Hotspot Further Evaluated

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    A checklist of the amphibians of Santa Teresa municipality, in southeastern Brazil is presented based on fieldwork, examination of specimens in collections, and a literature review. This new amphibian list of Santa Teresa includes 108 species, of which 106 (~98%) belong to Anura and two (~2%) to Gymnophiona. Hylidae was the most represented family with 47 species (43%). Compared to the previous amphibian lists for Santa Teresa, 14 species were added, 17 previously reported species were removed, and 13 species were re-identified based on recent taxonomic rearrangements. Of the 14 species added, 11 (79%) were first recorded during our fieldwork and specimen examination. It is also the first list of caecilians for Santa Teresa. This list suggests that Santa Teresa has 0.16 species per km2 (i.e., 108 species/683 km2), one of the highest densities of amphibian species in the world at a regional scale. This richness represents 78% of the 136 anurans from Espírito Santo state and 10% of the 1,080 amphibians from Brazil. We highlight the need for long-term monitoring to understand population trends and develop effective conservation plans to safeguard this remarkable amphibian richness

    Nonuniversality in the pair contact process with diffusion

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    We study the static and dynamic behavior of the one dimensional pair contact process with diffusion. Several critical exponents are found to vary with the diffusion rate, while the order-parameter moment ratio m=\bar{rho^2} /\bar{rho}^2 grows logarithmically with the system size. The anomalous behavior of m is traced to a violation of scaling in the order parameter probability density, which in turn reflects the presence of two distinct sectors, one purely diffusive, the other reactive, within the active phase. Studies restricted to the reactive sector yield precise estimates for exponents beta and nu_perp, and confirm finite size scaling of the order parameter. In the course of our study we determine, for the first time, the universal value m_c = 1.334 associated with the parity-conserving universality class in one dimension.Comment: 9 pages, 5 figure
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