2,698 research outputs found

    Small-sample corrections for score tests in Birnbaum-Saunders regressions

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    In this paper we deal with the issue of performing accurate small-sample inference in the Birnbaum-Saunders regression model, which can be useful for modeling lifetime or reliability data. We derive a Bartlett-type correction for the score test and numerically compare the corrected test with the usual score test, the likelihood ratio test and its Bartlett-corrected version. Our simulation results suggest that the corrected test we propose is more reliable than the other tests.Comment: To appear in the Communications in Statistics - Theory and Methods, http://www.informaworld.com/smpp/title~content=t71359723

    Situação da Sigatoka-Negra da bananeira no Brasil.

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    A bananicultura é uma das atividades de grande importância no agronegócio brasileiro, embora o País não seja um grande exportador de banana. A produção é da ordem de sete milhões de toneladas anuais, com vendas externas em torno de 2% da produção, ou seja, o mercado interno é o mais importante para a comercialização da fruta, que, em grande parte vem da agricultura familiar

    BioCode gold-nanobeacon for the detection of fusion transcripts causing chronic myeloid leukemia

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    This work was supported by Fundacao para a Ciencia e Tecnologia, Ministry of Science and Education (FCT/MEC) [PTDC/QUI-QUI/112597/2009; PTDC/BBB-NAN/1812/2012; CIGMH (PEST-OE/SAU/UI0009/2011); SFRH/BD/87836/2012 to M.C. and SFRH/BPD/88322/2012 to L.G.]; and by Unidade de Ciencias Biomoleculares Aplicadas-UCIBIO [(UID/Multi/04378/2013) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER-007728)].BACKGROUND: Gold-nanobeacons (Au-nanobeacons) have proven to be versatile systems for molecular diagnostics and therapeutic actuators. Here, we present the development and characterization of two gold nanobeacons combined with Förster resonance energy transfer (FRET) based spectral codification for dual mode sequence discrimination. This is the combination of two powerful technologies onto a single nanosystem. RESULTS: We proved this concept to detect the most common fusion sequences associated with the development of chronic myeloid leukemia, e13a2 and e14a2. The detection is based on spectral shift of the donor signal to the acceptor, which allows for corroboration of the hybridization event. The Au-nanobeacon acts as scaffold for detection of the target in a homogenous format whose output capability (i.e. additional layer of information) is potentiated via the spectral codification strategy. CONCLUSIONS: The spectral coded Au-nanobeacons permit the detection of each of the pathogenic fusion sequences, with high specificity towards partial complementary sequences. The proposed BioCode Au-nanobeacon concept provides for a nanoplatform for molecular recognition suitable for cancer diagnostics.publishersversionpublishe

    Braquiária na agropecuária brasileira: uma história de sucesso.

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    The Weibull-Geometric distribution

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    In this paper we introduce, for the first time, the Weibull-Geometric distribution which generalizes the exponential-geometric distribution proposed by Adamidis and Loukas (1998). The hazard function of the last distribution is monotone decreasing but the hazard function of the new distribution can take more general forms. Unlike the Weibull distribution, the proposed distribution is useful for modeling unimodal failure rates. We derive the cumulative distribution and hazard functions, the density of the order statistics and calculate expressions for its moments and for the moments of the order statistics. We give expressions for the R\'enyi and Shannon entropies. The maximum likelihood estimation procedure is discussed and an algorithm EM (Dempster et al., 1977; McLachlan and Krishnan, 1997) is provided for estimating the parameters. We obtain the information matrix and discuss inference. Applications to real data sets are given to show the flexibility and potentiality of the proposed distribution

    Ocorrência de eflorescências sulfatadas na mina de São Domingos

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    The intense exploration of sulphide ore deposit in São Domingos mine, produced considerable amount of sulphide material that when are exposed to weathering generates acid mine drainage (AMD). The main goal of this paper is to study a specific occurrence regarding composition and morphology of the salts that arise at the end of the dry season. Soluble salts appear at the banks of the drainage channels and over the waste materials, exhibiting different colours and aspects. The obtained results showed by X-Ray diffraction and scanning electronic microscopy, that the mineralogy of salt efflorescences is dominated by sulphates, displaying different occurrence modes. Melanterite and copiapite are the main iron sulphates while minerals from the series of pickeringite-halotrichite dominate the aluminium sulphates. In addition, dehydration and dissolution laboratory experiments were carried out in order to simulate the transformations suffered by soluble salts and evaluate the environmental effect in aquatic system.Patrícia Gomes wishes to acknowledge FCT (Science and Technology Foundation, Portugal) by the research fellowship under the POCH (Programa Operacional Capital Humano) supported by the European Social Fund and National Funds of MCTES with reference SFRH/BD/108887/2015. This work was co-funded by the European Union through the European Regional Development Fund, based on COMPETE 2020 (Programa Operacional da Competitividade e Internacionalização), project ICT (UID/GEO/04683/2013) with reference POCI-01-0145-FEDER-007690 and national funds provided by FCT (Science and Technology Foundation, Portugal)

    Molecular genotyping of sugarcane clones with microsatellite DNA markers

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    Molecular genotypes of 27 sugarcane clones (Saccharum hybrids) were produced with nine sugarcane microsatellites. A total of 52 alleles were identified using a capillary electrophoresis system with 41 alleles displaying varying degrees of polymorphism and the remaining 11 being monomorphic. There were eight alleles for sugarcane microsatellite SMC286CS, five for SMC334BS, eight for SMC336BS, four for SMC713BS, five for mSSCIR5, five for mSSCIR33, five for MCSA042E08, four for MCSA053C10, and eight for MCSA068G08. Presence or absence of these 52 alleles from a clone allowed the assignment of its arbitrary microsatellite genotype. The genetic relatedness among these clones was assessed using the CLUSTAL W algorithm with DNAMAN(R) software based on their arbitrary genotypes. With the exception of four clones, CP 70-321, HoCP 91-555, L 97-137 and Q124, six groups of clones were identified that shared at least 76% homology between their microsatellite genotypes. The software program also produced a bootstrapped phylogenetic tree with branch patterns that in general coincided with the putative pedigrees of these clones. The derivation of molecular genotypes such as these has enable sugarcane geneticists and breeders to verify the genetic pedigrees and purity of their sugarcane populations. These microsatellite genotypes can also aid in progeny selection and facilitate studies on allele transmission in this aneu-polyploidy crop

    Características morfoagronômicas da BRS Platina sob níveis de sombreamento.

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    A bananeira é uma fruteira muito utilizada na composição de sistemas agroflorestais (SAFs) no Brasil e na América Latina. Sua escolha para integrar os SAFs vai além da produção de alimento rico em carboidratos, vitaminas e minerais

    FINITE SIZE SCALING FOR FIRST ORDER TRANSITIONS: POTTS MODEL

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    The finite-size scaling algorithm based on bulk and surface renormalization of de Oliveira (1992) is tested on q-state Potts models in dimensions D = 2 and 3. Our Monte Carlo data clearly distinguish between first- and second-order phase transitions. Continuous-q analytic calculations performed for small lattices show a clear tendency of the magnetic exponent Y = D - beta/nu to reach a plateau for increasing values of q, which is consistent with the first-order transition value Y = D. Monte Carlo data confirm this trend.Comment: 5 pages, plain tex, 5 EPS figures, in file POTTS.UU (uufiles

    Tailored virtual reality for smart physiotherapy

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    Remote sensing and Virtual Reality (VR) are technologies that create new development opportunities in the field of serious games with application in physiotherapy. Thus, during a physiotherapy training session expressed by a game around the remote sensing of user body motion provides measurements that can be used for objective evaluation of physical therapy outcomes. In this work is presented a serious game for physiotherapy characterized by Kinect natural user interface and a set of VR games developed in the Unity3D. To provide patient electronic health record, game remote configuration as well as for data presentation for physiotherapist a mobile application was developed. Additionally, several training results expressed by upper limb, neck and spine angles are included in the paper.info:eu-repo/semantics/acceptedVersio
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