477 research outputs found
O USO INDEVIDO DA ALTERAÇÃO DA SINTAXE NAS ANÁLISES POST-HOC DE GEE E ANOVA NO SPSS
The online support of IBM SPSS proposes that users alter the syntax when performing post-hoc analyses for interaction effects of ANOVA tests. Other authors also suggest altering the syntax when performing GEE analyses. This being done, the number of possible comparisons (k value) is also altered, therefore influencing the results from statistical tests that k is a component of the formula, such as repeated measures-ANOVA and Bonferroni post-hoc of ANOVA and GEE. This alteration also exacerbates type I error, producing erroneous results and conferring potential misinterpretations of data. Reasoning from this, the purpose of this paper is to report the misuse and improper handling of syntax for ANOVAs and GEE post-hoc analyses in SPSS and to illustrate its consequences on statistical results and data interpretation.O suporte on-line do IBM SPSS propõe que os usuários alterem a sintaxe ao executar análises post-hoc para efeitos de interação de testes ANOVA. Outros autores também sugerem alterar a sintaxe ao realizar análises GEE. Assim sendo, o número de possíveis comparações (valor de k) também é alterado, influenciando, portanto, os resultados dos testes estatísticos de que k é um componente da fórmula, como na ANOVA de medidas repetidas e nos post-hoc de ANOVA e GEE. Essa alteração também agrava o erro do tipo I, produzindo resultados errôneos e conferindo possíveis interpretações errôneas dos dados. Com base nisso, o objetivo deste artigo é relatar o uso indevido e o manuseio inadequado da sintaxe nas análises post-hoc de ANOVAs e GEE no SPSS e ilustrar suas consequências nos resultados estatísticos e na interpretação dos dados
Human motion analysis and simulation tools: a survey
Computational systems to identify objects represented in image sequences and tracking their motion in a fully automatic manner, enabling a detailed analysis of the involved motion and its simulation are extremely relevant in several fields of our society. In particular, the analysis and simulation of the human motion has a wide spectrum of relevant applications with a manifest social and economic impact. In fact, usage of human motion data is fundamental in a broad number of domains (e.g.: sports, rehabilitation, robotics, surveillance, gesture-based user interfaces, etc.). Consequently, many relevant engineering software applications have been developed with the purpose of analyzing and/or simulating the human motion. This chapter presents a detailed, broad and up to date survey on motion simulation and/or analysis software packages that have been developed either by the scientific community or commercial entities. Moreover, a main contribution of this chapter is an effective framework to classify and compare motion simulation and analysis tools
Processing of continuous fibre reinforced thermoplastics
ECCM15 - 15TH EUROPEAN CONFERENCE ON COMPOSITE MATERIALS, Venice, Italy, 24-28 June 2012Towpregs
based on different fibres and thermoplastic matrices were processed for highly
demanding and more commercial applications by different composite processing
technologies. In the technologies used, compression moulding and pultrusion, the final
composite pr
ocessing parameters were studied in order to obtain composites with adequate
properties at industrial compatible production rates. The produced towpregs were tested to
verify its polymer content and degree of impregnation. The obtained results have shown t
hat
the coating line enabled to produce, with efficiency and industrial scale speed rates,
thermoplastic matrix towpregs
that may be used to manufacture
composites for
advanced and
larger volume commercial markets
Notes on the feeding habits of Gaidropsarus guttatus (Collett, 1890) from Faial Island, Azores, NE Atlantic, PT
Copyright © 2014 Société Française d’Ichtyologie.Gaidropsarus guttatus est un prédateur nocturne des fonds rocheux des îles de Macaronésie. Il n’existe pas d’étude sur l’écologie alimentaire de cette espèce et cet article apporte les toutes premières informations, sur la base d’un échantillon de 82 individus capturés à l’île de Faial, aux Açores (Portugal). Les prélèvements ont été réalisés entre août 1997 et avril 1999 dans des mares intertidales et en zone subtidale jusqu’à une profondeur de 10 m. Sur les 82 spécimens collectés, 95% d’entre eux présentaient des aliments dans l’estomac, totalisant 303 proies de 11 taxons différents. Les proies les plus fréquentes étaient des décapodes (45%), notamment le crabe Pachygrapsus marmoratus (24%). Les poissons téléostéens représentaient 17% de toutes les proies identifiées. La présence significative de proies benthiques et d’algues dans les contenus stomacaux de G. guttatus suggèrent que cette espèce est un prédateur opportuniste qui utilise la succion pour capturer ses proies.ABSTRACT: Gaidropsarus guttatus is a nocturnal predator that dwells in rocky bottoms of Macaronesian coastal areas. There are no studies as yet on the feeding ecology of this species. This paper describes the feeding habits of this quite unknown species, based on a sample from Faial Island, Azores, Portugal. This sample is composed of 82 specimens collected between August 1997 and April 1999, both in intertidal pools and sub-tidal shallow waters (max. depth 10 m). 95% of sampled stomachs contained food items totaling 303 preys from 11 different taxa. Most important items were decapoda (45%), from which Pachygrapsus marmoratus (24%) showed to be clearly a dominant prey. Teleost fish represented 17% of all prey items. The significant presence of benthonic species and algae in their stomach contents do suggest that G. guttatus is an opportunistic suction feeder predator
Processing of carbon reinforced thermoplastic pre-impregnated materials
The aim of this work is to produce and optimize the processing of carbon fibres thermoplastic matrix pre-impregnated materials (towpregs and PCT´s). Pultrusion and heated compression moulding were the selected manufacturing methods for processing all carbon fibres thermoplastic matrix pre-impregnated materials into composite parts.
The optimization of those processes was made by studying the influence of the most relevant processing parameters in the final properties of the produced carbon fibres thermoplastic matrix pre-impregnated materials and composites. The method of Taguchi / DOE (Design of Experiments) was used to achieve this aim as it allowed making more rational choices of processing windows.
The composite relevant mechanical properties were determined and studied. The final composites were also submitted to SEM microscopy analysis.info:eu-repo/semantics/publishedVersio
Compression molding of pultruded carbon reinforced thermoplastic composites
Historically, thermoset resins have dominated the composite industry but they start to be replaced
by thermoplastics. In this study two different thermoplastic matrix carbon reinforced pre-impregnated
materials were used, one produced in our laboratories (towpreg) and another obtained from coextrusion
process (PCT). Carbon fibre and two different thermoplastic matrices (polypropylene and
PRIMOSPIRE®) were selected for the production of the pre-impregnated materials.
Heated compression moulding and pultrusion were the two manufacturing technologies used to
obtain composite plates and profiles for study. The optimization of those processes was made by
studying the influence of the most relevant processing parameters in the final properties of the
produced carbon fibres thermoplastic matrix pre-impregnated materials and composites.
The composite relevant mechanical properties were determined and the final composites were
submitted to Dynamic Mechanical Analysis (DMA), Scanning Electron Microscope (SEM), optical
microscopy and calcination tests.
The determination of the fiber volume fraction of all studied composite was obtained comparing
the results of thermogravimetric analysis (TGA), SEM and calcination tests.info:eu-repo/semantics/publishedVersio
Stratégie alimentaire et ontogénie trophique de Scorpaena maderensis (Scorpaeniformes: Scorpaenidae) des Açores, Atlantique NE
Copyright © 2014 Société Française d'Ichtyologie.Feeding habits of Scorpaena maderensis Valenciennes, 1833 from the Azores archipelago were investigated. The stomach contents of 245 specimens, collected between August 1997 and July 1999, were analysed. Decapod crustaceans and teleost fishes constitute the main food items, revealing a high level of specialization by S. maderensis. Ontogenic shifts and seasonal changes in the diet composition were observed, unveiling the adaptability and opportunistic predatory behaviour of this scorpaenid.RÉSUMÉ: Les habitudes alimentaires de Scorpaena maderensis Valenciennes, 1833 de l'archipel des Açores ont été étudiées. Les contenus stomacaux de 245 spécimens, récoltés entre août 1997 et juillet 1999, ont été analysés. Les crustacés décapodes et les téléostéens sont les principales proies de S. maderensis, indiquant un fort degré de spécialisation chez cette espèce. Des changements ontogénétiques et saisonniers de la composition du régime alimentaire révèlent l’adaptabilité et le comportement prédateur opportuniste de ce scorpaenidé
Impact of SM parameters and of the vacua of the Higgs potential in gravitational waves detection
In this work we discuss two different phases of a complex singlet extension
of the Standard Model (SM) together with an extension that also includes new
fermion fields, in particular, a Majoron model equipped with an inverse seesaw
mechanism. All considered scenarios contain a global symmetry
and allow for first-order phase transitions while only two of them are strong
enough to favour the detection of primordial gravitational waves (GWs) in
planned experiments such as LISA. In particular, this is shown to be possible
in the singlet extension with a non vanishing real VEV at zero temperature and
also in the model with extra fermions. In the singlet extension with no
additional fermions, the detection of GWs strongly depends on the
symmetry breaking pattern of the scalar potential at zero
temperature. We study for the first time the impact of the precision in the
determination of the SM parameters on the strength of the GWs spectrum. It
turns out that the variation of the SM parameters such as the Higgs boson mass
and top quark Yukawa coupling in their allowed experimental ranges has a
notable impact on GWs detectability prospects.Comment: 28 pages, 13 figure
How vulnerable are cetaceans to climate change? Developing and testing a new index
info:eu-repo/semantics/publishedVersio
Effects of anobiid damage on shear strength parallel to the grain in single step joints
ABSTRACT: Traditional carpentry joints can be found worldwide in many timber truss structures connecting rafter and tie beam. One failure mode of this connection result from shear in the tie beam beyond the notch either due to bad design or deterioration. In this article, the reduction in shear strength of Single Step Joints (SSJ) resulting from biological attack by anobiids was analysed. For this purpose, tests were carried out in non-degraded scots pine (Pinus sylvestris L.) specimens (reference) and compared to artificially degraded specimens with three different levels of degradation. The reduction of shear resistance was analysed in relation to the density of holes drilled during the degradation simulation, the loss of mass, and the reduction of the shear-resistant area. At lower degradation levels, no significant reduction in shear strength was observed. On the other hand, the linear regression shows a trend of resistance reduction with increasing degradation. Despite the relatively low coefficient of determination (r2 = 0.25), the parameter that best correlated with the residual strength was the reduction in the shear-resistant area.info:eu-repo/semantics/publishedVersio
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