182 research outputs found

    A INFLUÊNCIA DA TECNOLOGIA NO DESENVOLVIMENTO ORGANIZACIONAL

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    A Teoria do Desenvolvimento Organizacional tomou força a partir da década de 1970. Os gestores perceberam que tomar conhecimento dessas competências tornou-se um diferencial frente à concorrência. A partir de uma pesquisa bibliográfica, o presente estudo buscou analisar a evolução da Teoria do Desenvolvimento Organizacional e as implicações das novas tecnologias no contexto das organizações. Buscou-se verificar as concepções que devem ser aplicadas nas empresas e como os colaboradores buscam melhorar o seu desempenho

    Influence of adhesive on optical fiber-based strain measurements on printed circuit boards

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    The use of optical fiber sensing for strain measurements on printed circuit boards is a recent approach, and there is a lack of f reliable methods to obtain valid strain measurements. This work investigates the influence of different adhesives and their application for strain measurements using optical fiber sensors on PCB, considering room and high temperature tests. Strain developed in PCB during production and quality testing are measured by a single distributed optical fiber sensor, interrogated by Optical Frequency Domain Reflectometry. Different adhesives are evaluated for room and high temperatures strain measurements. Different thicknesses of the adhesive layer are studied under tensile and bending loadings. The mechanical properties of the adhesives and their effectiveness in optical fiber measurements were evaluated. A suitable adhesive selection is required for reliable strain measurements under different testing requirements: cyanoacrylate based for room temperature testing; epoxy or polyimide-based for high temperature measurements. The adhesive thickness should be the lowest and uniformly applied. A linear relationship between adhesive thickness and strain error was found, being necessary the application of a correction factor for valid strain measurements. Optical distributed sensing is highlighted as an alternative approach to conventional strain gauges for PCB strain measurements, reducing the installation complexity, significantly enlarging the number of measured points, without reducing the quality of the strain measurements. Selection of the best adhesive is crucial, as well as its thickness for reliable strain measurements.Open access funding provided by FCT|FCCN (b-on). This work was supported by the European Structural and Investment Funds in the FEDER component, through the Operational Competitiveness and Internationalization Programme (COMPETE 2020) [Project n 839479; Funding Reference: POCI-01-0247-FEDER-39479]''. It was also funded by FEDER funds through the COMPETE 2020 program and National Funds through Fundacao para a Ciencia e a Tecnologia (FCT) to IPC under projects UIDB/05256/2020(IPC), UIDP/05256/2020 (IPC), UIDB/04436/2020(CMEMS) and UIDP/04436/2020 (CMEMS)

    Unpredictability in seasonal infectious diseases spread

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    In this work, we study the unpredictability of seasonal infectious diseases considering a SEIRS model with seasonal forcing. To investigate the dynamical behaviour, we compute bifurcation diagrams type hysteresis and their respective Lyapunov exponents. Our results from bifurcations and the largest Lyapunov exponent show bistable dynamics for all the parameters of the model. Choosing the inverse of latent period as control parameter, over 70% of the interval comprises the coexistence of periodic and chaotic attractors, bistable dynamics. Despite the competition between these attractors, the chaotic ones are preferred. The bistability occurs in two wide regions. One of these regions is limited by periodic attractors, while periodic and chaotic attractors bound the other. As the boundary of the second bistable region is composed of periodic and chaotic attractors, it is possible to interpret these critical points as tipping points. In other words, depending on the latent period, a periodic attractor (predictability) can evolve to a chaotic attractor (unpredictability). Therefore, we show that unpredictability is associated with bistable dynamics preferably chaotic, and, furthermore, there is a tipping point associated with unpredictable dynamics

    Combined analysis of weak lensing and X-ray blind surveys

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    We present a joint weak lensing and X-ray analysis of 4 deg2^2 from the CFHTLS and XMM-LSS surveys. Our weak lensing analysis is the first analysis of a real survey using shapelets, a new generation weak lensing analysis method. We create projected mass maps of the images, and extract 6 weak-lensing-detected clusters of galaxies. We show that their counts can be used to constrain the power spectrum normalisation σ8=0.920.30+0.26\sigma_8 =0.92_{-0.30}^{+0.26} for Ωm=0.24\Omega_m=0.24. We show that despite the large scatter generally observed in the M-T relation derived from lensing masses, tight constraints on both its slope and normalisation MM_* can be obtained with a moderate number of sources provided that the covered mass range is large enough. Adding clusters from Bardeau et al. (2007) to our sample, we measure M=2.710.61+0.791014h1MM_* = 2.71_{-0.61}^{+0.79} 10^{14} h^{-1} M_\odot. Although they are dominated by shot noise and sample variance, our measurements are consistent with currently favoured values, and set the stage for future surveys. We thus investigate the dependence of those estimates on survey size, depth, and integration time, for joint weak lensing and X-ray surveys. We show that deep surveys should be dedicated to the study of the physics of clusters and groups of galaxies. For a given exposure time, wide surveys provide a larger number of detected clusters and are therefore preferred for the measurement of cosmological parameters such as σ8\sigma_8 and MM_*. We show that a wide survey of a few hundred square degrees is needed to improve upon current measurements of these parameters. More ambitious surveys covering 7000 deg2^2 will provide the 1% accuracy in the estimation of the power spectrum and the M-T relation normalisations.Comment: MNRAS in press Matches accepted version. References update

    Cross preferences and genetic diversity of Psidium interspecific hybrids through morphoagronomic traits and resistance to Meloidogyne enterolobii

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    Abstract The introgression of M. enterolobii resistance-related genes in guava breeding programs can be compromised by incompatibility among Psidium species. This study aimed to evaluate the female parent preference and genetic diversity of Psidium interspecific hybrids using morphoagronomic traits and resistance to M. enterolobii. There were evaluated cross successes and germination from crosses between accesses of P. cattleyanum, P. guineense and P. guajava and the genetic diversity by Ward-MLM method of hybrids according to descriptors developed for the genus. Crosses were more successful when P. cattleyanum was the female parent. Germination was more successful in crosses involving P. cattleyanum and P. guajava. Four groups were formed. The group IV clustered the most resistant genotypes, composed by genotypes of P. cattleyanum x P. guineense, while the group II was the most susceptible. The groups I and III grouped some genotypes of P. cattleyanum x P. guajava with low levels of susceptibility. There are preferences of female parent species among crosses. Some individuals of groups I and III can be used as source of resistance genes for the breeding program, due the presence of favorable alleles inherited from guava parent. The high susceptibility leads to reduction in root development
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