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

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

Atributos químicos no perfil de solos cultivados com bananeira sob irrigação, no Projeto Formoso, Bom Jesus da Lapa, Bahia.

A utilização de solos de baixa fertilidade e a não manutenção de níveis adequados de nutrientes durante o ciclo da bananeira são fatores responsáveis pela baixa produtividade da cultura. Estudos sobre extração de nutrientes pela bananeira indicam que o potássio e o nitrogênio são os mais absorvidos pela planta, seguidos por cálcio, magnésio, enxofre e fósforo. Embora a bananeira necessite de grande quantidade de nutrientes, 66% da sua massa vegetativa é devolvida ao solo, na forma de pseudocaules, folhas e rizoma, portanto, uma recuperação significativa da quantidade de nutrientes, em razão da ciclagem dos mesmos. A bananeira é cultivada e se desenvolve em diversos tipos de solos, sendo que alguns apresentam limitações como baixa capacidade de troca catiônica (CTC) e saturação por bases (V%), alta acidez, baixo armazenamento de água e nutrientes, alto teor de argila 2:1, desbalanço entre cátions e outras. Contudo, essas áreas têm sido utilizadas com aplicação de diversas práticas de manejo visando reduzir essas limitações. Amostras em quatro perfis de diferentes solos cultivados com bananeira, sob irrigação, no Projeto Formoso, em Bom Jesus da Lapa-BA, classificados como Neossolo Quartzarênico (NQ), Latossolo Vermelho-Amarelo distrófico (LVAd), Argissolo Vermelho-Amarelo distrófico (PVAd) e Argissolo Vermelho-Amarelo eutrófico (PVAe) foram coletadas. As profundidades de amostragem foram definidas com base nas observações morfológicas (cor, textura e estrutura) dos perfis a campo e/ou na separação dos horizontes dos referidos solos. Na parte central de cada horizonte foram coletadas amostras de solo para determinação do pH em água, P, K, Ca, Mg, H+Al, soma de bases (SB), capacidade de troca catiônica (CTC), saturação por bases (V), matéria orgânica e microelementos (B, Zn, Cr, Ni, Cd, Pb e Hg).bitstream/item/87522/1/Id25348ALBorges.pdfDisponível em: Acesso em: 08 jan. 2009

Relação entre o equilíbrio e o medo de cair em idosos

O equilíbrio corporal constitui uma das funções mais importantes do organismo, estando por isso diretamente associado à qualidade de vida do indivíduo. Algumas das alterações decorrentes do processo de envelhecimento, nomeadamente a nível músculo-esquelético, neuromuscular e sensorial, influenciam a mobilidade funcional e a capacidade para manter a estabilidade em indivíduos idosos1. As manifestações de desequilíbrio levam a uma maior predisposição para quedas e suas consequências diretas como fraturas, imobilidade e medo de cair, levando a uma redução da autonomia pessoal e social e a uma limitação das atividades da vida diária (AVD’s), interferindo na qualidade de vida e podendo, nalguns casos, conduzir à morte

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

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

[Carotid atherosclerosis and white matter hypodensities: a controversial relationship]

INTRODUCTION: White matter hypodensities of presumed vascular origin, are recognized as an important cause of morbidity with established clinical and cognitive consequences. Nonetheless, many doubts remain on its physiopathology. Our goal is to clarify the potential role of carotid atherosclerosis and other vascular risk factors in the development of white matter hypodensities of presumed vascular origin. MATERIAL AND METHODS: We included patients that underwent CT brain scan and neurosonologic evaluation within a one-month period. Full assessment of vascular risks factors was performed. We seek to find independent associations between white matter hypodensities of presumed vascular origin, carotid intima-media thickness and vascular risk factors. RESULTS: 472 patients were included, mean age was 67.32 (SD: 14.75), 274 (58.1%) were male. The independent predictors of white matter hypodensities of presumed vascular origin were age (OR: 1.067, 95% IC: 1.049 - 1.086, p < 0.001) and hypertension (OR: 1.726, 95% IC: 1.097 - 2.715, p = 0.018). No association was found between IMT (OR: 2.613, 95% IC: 0.886 - 7.708, p = 0.082) or carotid artery stenosis (OR: 1.021, 95% IC: 0.785 - 1.328, p = 0.877) and white matter hypodensities of presumed vascular origin. DISCUSSION: Only age and hypertension proved to have an independent association with white matter hypodensities of presumed vascular origin. Carotid atherosclerosis, evaluated by IMT and the degree of carotid artery stenosis, showed no association with white matter hypodensities of presumed vascular origin. Since atherosclerosis is a systemic pathology, these results suggest that alternative mechanisms are responsible for the development of white matter hypodensities of presumed vascular origin. CONCLUSION: Age and hypertension seem to be the main factors in the development of white matter hypodensities of presumed vascular origin. No association was found between carotid atherosclerosis and white matter hypodensities of presumed vascular origin

Vortex and gap generation in gauge models of graphene

Effective quantum field theoretical continuum models for graphene are investigated. The models include a complex scalar field and a vector gauge field. Different gauge theories are considered and their gap patterns for the scalar, vector, and fermion excitations are investigated. Different gauge groups lead to different relations between the gaps, which can be used to experimentally distinguish the gauge theories. In this class of models the fermionic gap is a dynamic quantity. The finite-energy vortex solutions of the gauge models have the flux of the "magnetic field" quantized, making the Bohm-Aharonov effect active even when external electromagnetic fields are absent. The flux comes proportional to the scalar field angular momentum quantum number. The zero modes of the Dirac equation show that the gauge models considered here are compatible with fractionalization

Braquiária na agropecuária brasileira: uma história de sucesso.

bitstream/item/99413/1/cap1.pd

Análise comparativa de rentabilidade: Brs Platina e Prata Anã.

A banana é a segunda fruta ais produzida e consumida no Brasil, com área colhida de 503 mil hectares e produção de 7,3 milhões de toneladas em 2011 (1). A maior parte do cultivo é realizada em pequenas propriedades. A variedade de maior produção e comercialização no Brasil é a ?Prata Anã?. No entanto, a suscetibilidade à Sigatoka-amarela e ao mal-do-Panamá estimulou a busca por variedades resistentes a tais doenças, resultando na variedade ?BRS Platina?

Tailored virtual reality for smart physiotherapy

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

Comportamento da Bananeira Prata Anã frente ao aumento da concentração de CO2.

As previsões são de aumento na concentração de CO2 atmosférico, passando dos atuais 380 ppm, para 550 ppm na metade desse século (2). Conhecer como a cultura da banana se comportará frente a esse crescente aumento do CO2 será importante para os profissionais da cadeia agrícola dessa cultura