9,611 research outputs found

    The 24-Cell and Calabi-Yau Threefolds with Hodge Numbers (1,1)

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    Calabi-Yau threefolds with h^11(X)=h^21(X)=1 are constructed as free quotients of a hypersurface in the ambient toric variety defined by the 24-cell. Their fundamental groups are SL(2,3), a semidirect product of Z_3 and Z_8, and Z_3 x Q_8.Comment: 22 pages, 3 figures, 3 table

    Detection of neutral hydrogen in early-type dwarf galaxies of the Sculptor Group

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    We present our results of deep 21 cm line (HI) observations of five early and mixed-type dwarf galaxies in the nearby Sculptor group using the ATNF 64m Parkes Radio Telescope. Four of these objects, ESO294-G010, ESO410-G005, ESO540-G030, and ESO540-G032, were detected in HI with neutral hydrogen masses in the range of 2-9x10^5 M_{\odot} (MHI/LBM_{HI}/L_{B} = 0.08, 0.13, 0.16, and 0.18, respectively). These HI masses are consistent with the gas mass expected from stellar outflows over a large period of time. Higher resolution radio data from the Australia Telescope Compact Array were further analysed to measure more accurate positions and the distribution of the HI gas. In the cases of dwarfs ESO294-G010 and ESO540-G030, we find significant offsets of 290 pc and 460 pc, respectively, between the position of the HI peak flux and the center of the stellar component. These offsets are likely to have internal cause such as the winds from star-forming regions. The fifth object, the spatially isolated dwarf elliptical Scl-dE1, remains undetected at our 3\sigma limit of 22.5 mJy km/s and thus must contain less than 10^5 M_{\odot} of neutral hydrogen. This leaves Scl-dE1 as the only Sculptor group galaxy known where no interstellar medium has been found to date. The object joins a list of similar systems including the Local Group dwarfs Tucana and Cetus that do not fit into the global picture of the morphology-density relation where gas-rich dwarf irregulars are in relative isolation and gas-deficient dwarf ellipticals are satellites of more luminous galaxies.Comment: 21 pages, 4 figures, to be published in AJ (accepted

    EXTENSÃO UNIVERSITÁRIA: AVALIAÇÃO DOS PROJETOS DE EXTENSÃO DO USJ SOB A PERSPECTIVA DA INCLUSÃO SOCIAL

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    Este estudo objetiva analisar os projetos de extensão desenvolvidos, no ultimo biênio 2013/2014, no centro universitário de São José (SC). O trabalho foi construído sob a perspectiva de que os projetos de extensão constituem um canal de inclusão social, atribuindo, exploratório e descritivo, pois contextualiza as características da instituição e analisa a política dos trabalhos de extensão da entidade. Os resultados encontrados à universidade de ensino público, a tarefa de colaborar na administração social, estabelecendo a oxigenação da academia que se alimenta das experiências do meio onde está inserida. O estudo é classificado como qualitativo exploratório e descritivo. Os resultados da pesquisa apontam, que embora os projetos de extensão alcancem a proposta de canal com a sociedade, identificam-se desconexões entre os objetivos da maior parte dos projetos analisados, o edital de seleção dos projetos e o artigo 44 da Lei nº 9.394/96

    Structure Learning in a Sensorimotor Association Task

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    Learning is often understood as an organism's gradual acquisition of the association between a given sensory stimulus and the correct motor response. Mathematically, this corresponds to regressing a mapping between the set of observations and the set of actions. Recently, however, it has been shown both in cognitive and motor neuroscience that humans are not only able to learn particular stimulus-response mappings, but are also able to extract abstract structural invariants that facilitate generalization to novel tasks. Here we show how such structure learning can enhance facilitation in a sensorimotor association task performed by human subjects. Using regression and reinforcement learning models we show that the observed facilitation cannot be explained by these basic models of learning stimulus-response associations. We show, however, that the observed data can be explained by a hierarchical Bayesian model that performs structure learning. In line with previous results from cognitive tasks, this suggests that hierarchical Bayesian inference might provide a common framework to explain both the learning of specific stimulus-response associations and the learning of abstract structures that are shared by different task environments

    Estudo comparativo de carcaças de suínos dos diferentes gupos genéticos produzidos na regiao Centro-Sul do Paraná

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    Resumo: Com objetivo de avaliar o rendimento de carne magra dos diferentes grupos genéticos de suínos produzidos na região Centro-Sul do Estado do Paraná, foram medidas 5.490 carcaças, com pistola com sonda de refletância de luz HENNESSY GP4, na linha de abate da Cooperativa Central de Laticínios do Paraná Ltda, sendo estas pertencentes a oito genótipos diferentes, oriundos de sete granjas comerciais. Os animais abatidos foram alimentados ad libitum desde a fase inicial à terminação, com ração de mesmo padrão nutricional. As demais condições ambientais foram semelhantes. Os resultados foram submetidos à análise de variância pelo Método dos Quadrados Mínimos e as médias dos tratamentos comparadas pelo teste de Newman Keuls a 1 e 5 %. Os rendimentos de carne magra por grupo genético foram: 57,50 ± 3,28 %, 56,95 ± 3,09 %, 55,51 ± 2,83 %, 55,49 ± 3,32 %, 55,16 ± 3,69 %, 54,63 ± 3,70 %, 54,27 ± 3,56 % e 54,17 ± 3,69 % para AGPIC AGxDAL, DALLAND, FxJSR, JSR, FxSAD, FxDAL e F1000 respectivamente; sendo encontradas diferenças estatísticas altamente significativas entre genótipos (P<0,01). Quanto ao sexo, os rendimentos foram de 56,75 ± 3,34 % e 54,76 ± 3,56 % para fêmeas e machos respectivamente, sendo esta diferença altamente significativa (P<0,01). Os rendimentos por granja foram: 57,37 ± 3,18 %, 56,28 ± 3,24 %, 55,51 ± 2,83 %, 55,14 ± 3,42 %, 54,64 ± 3,64 %, 54,36 ± 3,69 % e 54,06 ± 3,61 % para GR1, GR3, GR7, GR2, GR5, GR4, GR6 respectivamente, sendo encontradas diferenças estatísticas altamente significativas entre granjas (P<0,01). Portanto, a produção de carcaças de maior rendimento, entre outros fatores, dependeu do genótipo utilizado. Palavras-chave: Suínos; Rendimento de Carne; Carcaça Suína; Grupo Genético

    Photodissociation and the Morphology of HI in Galaxies

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    Young massive stars produce Far-UV photons which dissociate the molecular gas on the surfaces of their parent molecular clouds. Of the many dissociation products which result from this ``back-reaction'', atomic hydrogen \HI is one of the easiest to observe through its radio 21-cm hyperfine line emission. In this paper I first review the physics of this process and describe a simplified model which has been developed to permit an approximate computation of the column density of photodissociated \HI which appears on the surfaces of molecular clouds. I then review several features of the \HI morphology of galaxies on a variety of length scales and describe how photodissociation might account for some of these observations. Finally, I discuss several consequences which follow if this view of the origin of HI in galaxies continues to be successful.Comment: 18 pages, 7 figures in 8 files, invited review paper for the conference "Penetrating Bars Through Masks of Cosmic Dust: The Hubble Tuning Fork Strikes a New Note", South Africa, June 2004. Proceedings to be published by Kluwer, eds. D.L. Block, K.C. Freeman, I. Puerari, R. Groess, & E.K. Bloc

    Robot@factory lite competition: a digital twin approach for the AGV

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    Robotics competitions are environments that foster teamwork, AI, and technology development by encouraging students, researchers, and academics to test their solutions against each other. These competitions often challenge the competitors’ prototypes with tasks specifically designed to benchmark them with the current optimal solutions. During the prototype stages of a robot, the development costs and time spent are often higher than other stages, as changes in the prototype are frequent. Simulation is often used to reduce these variables as it allows flexibility in all development stages before transitioning to the real scenario. However, a digital twin can be used to increase even further flexibility and effectiveness. Digital twins are virtual representations of real assets, providing replication and prediction of real scenario events, and real-time monitoring of the real object. Thus, this paper presents the development of a digital twin of an automatic guided vehicle (AGV) to the Robot@Factory Lite competition and the tests performed to validate the approach.The project that gave rise to these results received the support of a fellowship from ”la Caixa” Foundation (ID 100010434). The fellowship code is LCF/BQ/DI20/11780028. This work is financed by National Funds through the Portuguese funding agency, FCT - Fundação para a Ciência e a Tecnologia within project UIDB/50014/2020.info:eu-repo/semantics/publishedVersio

    Three-dimensional scanning system based on a low-cost infrared sensor

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    Nowadays, with the availability of 3D printers, the scanners for objects are becoming increasingly present since they allow to replicate objects by 3D printing, especially for small scale sizes. However, the majority of these technologies are expensive, due to the complexity of this task. Therefore, this work presents a prototype of a low-cost 3D scanning system for small objects using a point cloud to stereolithography approach where it was already validated in simulation in previous work. This concept has a restriction that the objects must have a uniform shape, i.e, without discontinuities. The architecture is composed of two stepper motors, due to their precision, a rotating plate to allow 360 degrees scans and another rotating structure that allows the infrared distance sensor to scan the object from bottom to top (90 degrees). The prThis work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/05757/2020. The project that gave rise to these results received the support of a fellowship from ”la Caixa” Foundation (ID 100010434). The fellowship code is LCF/BQ/DI20/11780028.info:eu-repo/semantics/publishedVersio

    High-Definition Optical Coherence Tomography for the in vivo Detection of Demodex Mites

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    Background: Demodex mites are involved in different skin diseases and are commonly detected by skin scrape tests or superficial biopsies. A new high-definition optical coherence tomography (HD-OCT) with high lateral and axial resolution in a horizontal (en-face) and vertical (slice) imaging mode might offer the possibility of noninvasive and fast in vivo examination of demodex mites. Methods: Twenty patients with demodex-related skin diseases and 20 age- and gender-matched healthy controls were examined by HD-OCT. Mites per follicle and follicles per field of view were counted and compared to skin scrape tests. Results: HD-OCT images depicted mites in the en-face mode as bright round dots in groups of 3-5 mites per hair follicle. In the patients with demodex-related disease, a mean number of 3.4 mites per follicle were detected with a mean number of 2.9 infested follicles per area of view compared to a mean of 0.6 mites in 0.4 infested follicles in the controls. The skin scrape tests were negative in 21% of the patients. Conclusion: The innovative HD-OCT enables fast and noninvasive in vivo recognition of demodex mites and might become a useful tool in the diagnosis and treatment monitoring of demodex-related skin diseases. Copyright (C) 2012 S. Karger AG, Base
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