3,658 research outputs found

    A sociometria na administração de recursos humanos.

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    Este estudo explora o teste sociométrico aplicado a um grupo de 49 indivíduos recém admitidos na Empresa Brasileira de Pesquisa Agropecuária - EMBRAPA, com o objetivo de subsidiar o processo de integração desses novos empregados a organização. A analise focaliza três estruturas grupais, nas quais se pode observar como ocorrem as primeiras relações interpessoais num grupo novo, como poderão se reestruturar e os prováveis lideres para situações de trabalho

    Combinatorial simplex algorithms can solve mean payoff games

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    A combinatorial simplex algorithm is an instance of the simplex method in which the pivoting depends on combinatorial data only. We show that any algorithm of this kind admits a tropical analogue which can be used to solve mean payoff games. Moreover, any combinatorial simplex algorithm with a strongly polynomial complexity (the existence of such an algorithm is open) would provide in this way a strongly polynomial algorithm solving mean payoff games. Mean payoff games are known to be in NP and co-NP; whether they can be solved in polynomial time is an open problem. Our algorithm relies on a tropical implementation of the simplex method over a real closed field of Hahn series. One of the key ingredients is a new scheme for symbolic perturbation which allows us to lift an arbitrary mean payoff game instance into a non-degenerate linear program over Hahn series.Comment: v1: 15 pages, 3 figures; v2: improved presentation, introduction expanded, 18 pages, 3 figure

    Upwelling regime off the Cabo Frio region in Brazil and impact on acoustic propagation

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    This work introduces a description of the complex upwelling regime off the Cabo Frio region in Brazil and shows that ocean modeling, based on the feature-oriented regional modeling system (FORMS) technique, can produce reliable predictions of sound speed fields for the corresponding shallow water environment. This work also shows, through the development of simulations, that the upwelling regime can be responsible for the creation of shadow coastal zones, in which the detection probability is too low for an acoustic source to be detected. The development of the FORMS technique and its validation with real data, for the particular region of coastal upwelling off Cabo Frio, reveals the possibility of a sustainable and reliable forecast system for the corresponding (variable in space and time) underwater acoustic environment. (C) 2018 Acoustical Society of AmericaBrazilian Navy; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)/Ciencias Sem Fronteiras [400671/2014-0]; European Union [OAEX-230855]; Fundacao de Amparo a Pesquisa (FAPERJ) [E-26/110.327/2012

    Comportamento biométrico de cultivares de banana sob irrigaçao localizada no Recôncavo Baiano.

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    O Brasil em 2012 produziu aproximadamente 6,9 milhões de toneladas de bananas, sendo o quinto maior produtor mundial, após Índia, Filipinas, China e Equador (FAO, 2012). Segundo o IBGE (2012), a região Nordeste é a principal produtora, responsável por 37,9% da produção, e o estado da Bahia o segundo maior produtor. No entanto, a produtividade nacional tem se mostrado muito aquém de seu potencial em função de problemas nutricionais e de suprimento hídrico, apesar de existir condições favoráveis para seu cultivo em quase todo o país. O baixo rendimento constatado nas regiões produtoras de banana evidencia a necessidade de ajustes tecnológicos e de manejo da cultura nas diversas áreas do conhecimento

    Natural DNA-recombinations of Spodoptera littoralis NPV among field populations in Egypt

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    Six natural isolates belonging to #Spodotera littoralis$ NPV were identified. Using the restriction endonucleases Eco RI and Bam HI, the DNA profiles of each isolate from Giza, Menya, Kaliubeia-Kaha, Kafr El-Sheikh, Gharbeia and Kaliubeia-Tokh were differentiated from that of the reference Egypt-84. DNA electrophoretic profiles on different isolates collected 5 years later were compared to the difference type. The DNA sequence was not changed trough three serial passages of viral isolates in vivo, while several viral clones were obtained after the 4th passage. (Résumé d'auteur

    Transitions from small to large Fermi momenta in a one-dimensional Kondo lattice model

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    We study a one-dimensional system that consists of an electron gas coupled to a spin-1/2 chain by Kondo interaction away from half-filling. We show that zero-temperature transitions between phases with "small" and "large" Fermi momenta can be continuous. Such a continuous but Fermi-momentum-changing transition arises in the presence of spin anisotropy, from a Luttinger liquid with a small Fermi momentum to a Kondo-dimer phase with a large Fermi momentum. We have also added a frustrating next-nearest-neighbor interaction in the spin chain to show the possibility of a similar Fermi-momentum-changing transition, between the Kondo phase and a spin-Peierls phase, in the spin isotropic case. This transition, however, appears to involve a region in which the two phases coexist.Comment: The updated version clarifies the definitions of small and large Fermi momenta, the role of anisotropy, and how Kondo interaction affects Luttinger liquid phase. 12 pages, 5 figure

    Element behaviour during combustion in coal-fired Orhaneli power plant, Bursa-Turkey

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    This study focuses on element behaviour during combustion in the Orhaneli thermal power plant (a 210 MW unit, Bursa-Turkey). A total of 51 samples, feed coals (FCs), fly ashes (FAs) and bottom ashes (BAs), which were systematically collected over an eight-week period, have been analysed for major, minor and trace elements (Al, Ca, Fe, K, Mg, Na, S, As, B, Ba, Be, Bi, Cd, Co, Cr, Cs, Cu, Ga, Ge, Hf, Hg, Li, Mn, Mo, Nb, Ni, P, Pb, Rb, Sb, Sc, Se, Sn, Sr, Ta, Th, Ti, Tl, U, V, W, Y, Zn, Zr and REEs). This study shows that FCs on an airdried basis have high moisture (av. 9%), high volatile matter (av. 33%), very high ash yield (av. 53%), relatively high sulfur content (av. 2.14%) and low gross calorific value (av. 1775 kcal/kg). Proximate analyses of combustion residues imply that BAs have higher contents of unburned carbonaceous matter than FAs. Mean values of trace element concentrations in FCs fall within the ranges of most world coals, except for Cr, Cs, Ni and U which occur in concentrations slightly higher than those determined for most of world coals. Some elements such as S, Hg, As, B, Bi, Cd, Cs, Ge, K, Pb, Rb, Sb, Se, Sn, Tl, and Zn are indicating enrichments in FAs. The remaining elements investigated in this study have no clear segregation between FAs and BAs. The mass balance calculations point to Ca content of feed coal controlling the partitioning of elements in this power plant, producing a high removal efficiency for highly volatile elements such as Hg, B and Se, and a high retention of As, Bi, Cd, Cs, Ge, Pb, Rb, Sb, Sn, Tl and Zn in FAs. However, the high enrichment in trace elements of FAs can increase the hazardous potential of this coal by-product

    Photometric type Ia supernova surveys in narrow band filters

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    We study the characteristics of a narrow band type Ia supernova survey through simulations based on the upcoming Javalambre Physics of the accelerating universe Astrophysical Survey (J-PAS). This unique survey has the capabilities of obtaining distances, redshifts, and the SN type from a single experiment thereby circumventing the challenges faced by the resource-intensive spectroscopic follow-up observations. We analyse the flux measurements signal-to-noise ratio and bias, the supernova typing performance, the ability to recover light curve parameters given by the SALT2 model, the photometric redshift precision from type Ia supernova light curves and the effects of systematic errors on the data. We show that such a survey is not only feasible but may yield large type Ia supernova samples (up to 250 supernovae at z<0.5z<0.5 per month of search) with low core collapse contamination (1.5\sim 1.5 per cent), good precision on the SALT2 parameters (average σmB=0.063\sigma_{m_B}=0.063, σx1=0.47\sigma_{x_1}=0.47 and σc=0.040\sigma_c=0.040) and on the distance modulus (average σμ=0.16\sigma_{\mu}=0.16, assuming an intrinsic scatter σint=0.14\sigma_{\mathrm{int}}=0.14), with identified systematic uncertainties σsys0.10σstat\sigma_{\mathrm{sys}}\lesssim 0.10 \sigma_{\mathrm{stat}}. Moreover, the filters are narrow enough to detect most spectral features and obtain excellent photometric redshift precision of σz=0.005\sigma_z=0.005, apart from \sim 2 per cent of outliers. We also present a few strategies for optimising the survey's outcome. Together with the detailed host galaxy information, narrow band surveys can be very valuable for the study of supernova rates, spectral feature relations, intrinsic colour variations and correlations between supernova and host galaxy properties, all of which are important information for supernova cosmological applications.Comment: 20 pages, 12 tables and 26 figures. Version accepted by MNRAS, with results slightly different from previous on

    Silicone Adhesives in Medical Applications

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    This chapter will review silicone based adhesive technologies, applications and characterization, emphasizing those self-adhesive materials often used in skin contact applications including transdermal drug delivery and wound care device attachment. The silicone pressure sensitive adhesives used in transdermal applications today are thermoplastic and based on silicone polymer and silicate resin chemistries. Previous research has suggested that some drugs readily diffuse through silicone adhesives, prompting their use in transdermal patches. A recently developed silicone acrylate hybrid adhesive technology combines polyacrylate and silicone molecular structures to form a stable, semi-interpenetrated network. This technology provides ease in formulating transdermal drug delivery systems through improved physical stability over simple blends of acrylate and silicone adhesives. The ability of some silicone adhesives to affix bandages without disrupting the wound bed upon removal has led to the wide acceptance of a third type of silicone adhesive technology that unlike the aforementioned thermoplastic materials is thermoset. This adhesive form is based on a platinum catalyzed, cross-linking reaction between vinyl functional and silicon-hydride functional silicone polymers. The various silicone adhesive types have been characterized via classical measurements of physical performances. Rheological techniques elucidated herein provide further understanding of the structure-property relationships previously unavailable using classical characterization approaches
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