Lasso Estimation of an Interval-Valued Multiple Regression Model

A multiple interval-valued linear regression model considering all the cross-relationships between the mids and spreads of the intervals has been introduced recently. A least-squares estimation of the regression parameters has been carried out by transforming a quadratic optimization problem with inequality constraints into a linear complementary problem and using Lemke's algorithm to solve it. Due to the irrelevance of certain cross-relationships, an alternative estimation process, the LASSO (Least Absolut Shrinkage and Selection Operator), is developed. A comparative study showing the differences between the proposed estimators is provided

Efeito do confinamento em secções parcialmente embebidas com betão

As secções parcialmente embebidas com betão silo uma solução de construção mista que utiliza um perfil metálico parcialmente revestido com betão reforçado. Esta característica construtiva aumenta a resistência do perfil metálico à temperatura ambiente e em particular, quando submetido a condições de incêndio. Neste artigo é efectuado um estudo paramétrico sobre a influência do confinamento do betão na resistência última de elementos parcialmente embebidos, quando submetidos à flexão. É apresentado um estudo numérico não linear, geométrico e material, em relação ao valor do grau de confinamento e em relação ao factor efectivo de confinamento

Aportaciones desde la biomecánica de la natación de competición

A natação é uma modalidade individual, cíclica e fechada, pelo que, no respectivo quadro de factores determinantes do sucesso competitivo, a optimização do gesto técnico desempenha um papel determinante.info:eu-repo/semantics/publishedVersio

Relationships between energy cost, swimming velocity and speed fluctuation in elite butterfliers

In swimming science, economy of movement is an interesting field of research. Several investigations have been conducted to understand the role of bioenergetical profile to performance. Most of those studies focused exclusively on the contribution of The individual correlations between E-tot and v ranged from R=0.95 aerobic system to produce energy for movement, even though all competitive swimming events also require significant (p=0.05) to R=0.90 (p<0.01). For pooled data the relationship was contribution from anaerobic energetic system to cover total energy expenditure. R=0.70 (p<0.01). The individual correlations between EC and d

On certain homological invariant and its relation with Poincaré duality pairs

Let G be a group, S = {Sᵢ, i ∊ I} a non empty family of (not necessarily distinct) subgroups of infinite index in G and M a Z₂G-module. In [4] the authors defined a homological invariant E*(G, S,M), which is “dual” to the cohomological invariant E(G, S,M), defined in [1]. In this paper we present a more general treatment of the invariant E*(G, S,M) obtaining results and properties, under a homological point of view, which are dual to those obtained by Andrade and Fanti with the invariant E(G, S,M). We analyze, through the invariant E*(G, S,M), properties about groups that satisfy certain finiteness conditions such as Poincaré duality for groups and pairs

MAPEAMENTO GEOMORFOLÓGICO COMO SUBSÍDIO AO PLANEJAMENTO AMBIENTAL NO MUNICÍPIO DE QUIXADÁ/CE.

O presente trabalho teve como objetivo elaborar o mapeamento geomorfológico do município de Quixadá, localizado no sertão central do Estado do Ceará, utilizando – o como subsídio ao planejamento ambiental em regiões semiáridas. O mapeamento foi realizado seguindo a metodologia de Ross (1992) tendo como critério a taxonomia do relevo, em escala de 1:40.000. A área foi classificada até o 4° nível taxonômico, onde são evidenciados seus padrões dominantes (ambientes de degradação e agradação)

Energy cost and intracyclic variation of the velocity of the centre of mass in butterfly stroke

The purpose of this study was to examine the relationship between the intra-cycle variation of the horizontal velocity of displacement (dV) and the energy cost (EC) in butterfly stroke. Five Portuguese national level swimmers performed one maximal and two submaximal 200-m butterfly swims. The oxygen consumption was measured breath-by-breath by portable metabolic cart. A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyse blood lactate concentration. Total energy expenditure (Etot) and EC were calculated for each swim. The swims were videotaped in the sagittal plane with a set of two cameras providing dual projection from both underwater and above the water surface. The APAS system was used to analyse dV for the centre of mass. The Etot increased linearly with the increasing V, presenting a significant correlation coefficient between these parameters (r=0.827, P<0.001). The increase in EC was significantly associated with the increase in the dV (r=0.807, P<0.001). All data were presented as the mean value and the standard deviation. It is concluded that high intra-cycle variation of the velocity of the centre of mass was related to less efficient swimming and vice versa for the butterfly stroke

Speed fluctuation as a determinant factor of energy cost in Butterfly stroke

The purpose of this study was to examine the relationships between the speed fluctuation of the centre of mass and the EC, in butterfly stroke. Five national level Portuguese swimmers performed one maximal and two sub-maximal (85% and 75%) 200-m butterfly swims in a 25-m swimming pool. Cardio-pulmonary and gas exchange parameters were measured breath by breath for each swim to analyze VO2 and other energetic parameters by portable metabolic cart (K4b2, Cosmed, Rome, Italy). A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyze blood lactate concentration (YSI 1500L, Yellow Springs, US). Total energy expenditure (È-tot) and EC were calculated for each swim. The swims were videotaped (50 Hz) in sagital plane with a set of two cameras providing dual-media images from both underwater and above the water surface. The cameras were real time synchronised and the images were edited on a mixing table to create one single image of dual-media. APAS system (Ariel Dynamics Inc, USA) was used to analyse speed fluctuation for the centre of mass. Coefficients of variation for the horizontal velocity of the centre of mass along the stroke cycle (dV) were calculated. Linear regressions between the bioenergetic and biomechanical variables were computed, as well as, its 0.05). Coefficients of determination and correlation (p). There was a significant and linear relationship between È-tot and velocity (r=0.827, p=0.0005). Statistically significant correlation coefficient between the EC and the dV (r=0.807, p=0.0009) was found, the coefficient of determination being r2=0.651. This means that the increase in the EC being strongly associated with the increase in the speed fluctuation. The individual coefficients of correlation and determination between the EC and the dV were very high (mean r2 0.018, ranging from 0.973 to 1.000). The mean of individual correlation È= 0.986 0.009 coefficients was higher than the overall correlation coefficient (r=0.993 vs r=0.807) of the pooled data. It is concluded that the speed fluctuation of the centre of mass was related to less efficient swimming and vice versa in butterfly. We suggest that the swimmers should strive to improve their technique performances by avoiding large variations in the speed fluctuation.info:eu-repo/semantics/publishedVersio

Direct and Inverse Magnetocaloric effects in A-site ordered PrBaMn2O6 manganite in low magnetic fields

The magnetocaloric effect (MCE) of A-site ordered PrBaMn2O6 manganite has been studied by direct methods and by the specific heat measurements. Direct measurements of the MCE in low magnetic fields were performed using recently proposed modulation technique and by classic direct method in high fields. Direct and inverse MCE are observed at Curie and Neel points correspondingly. A value of the inverse MCE in the heating run is less than in the cooling regime. This effect can be attributing to competition between ferromagnetic and antiferromagnetic interactions. Indirectly estimated and direct MCE values considerably differ in around first order AF transition.Comment: 8 pages, 5 figure

Configured distribution of the celiac artery in blue-fronted amazon (Amazona aestiva)

Foram descritas a origem e a distribuição da artéria celíaca em 20 papagaios-verdadeiros (Amazona aestiva), por meio do preenchimento do sistema arterial com solução de látex corado, fixado em solução de formol, para posterior dissecação de seus ramos colaterais. Como primeiro ramo, a artéria célica emitiu a artéria proventricular dorsal, que seguiu para o ventrículo como artéria gástrica dorsal e, em seguida, enviou a artéria proventricular ventral, que em 85% dos exemplares se originou diretamente da artéria celíaca, ou do seu ramo esquerdo em 15%. Em 25% dos casos, a artéria esplênica foi emitida antes da bifurcação em ramo esquerdo e direito. O ramo esquerdo foi responsável pela origem de ramos proventriculares, ramos pilóricos, artéria esplênica e artéria proventricular ventral, a qual emitiu ramos ao proventrículo e ao esôfago. A artéria celíaca também originou as artérias gástrica ventral e gástrica esquerda, que foram responsáveis pela emissão da artéria hepática esquerda. O ramo direito emitiu artérias esplênicas − que variaram de uma a sete −, duodenal − destinada ao segmento mais caudal da alça ascendente do duodeno, hepática direita − para o lobo direito do fígado. Em seu segmento terminal, o ramo direito dividiu-se em artérias gástrica direita − para o ventrículo −, pancreaticoduodenal − para o pâncreas, alças ascendente e descendente do duodeno e segmentos cranial do íleo e caudal do jejuno. A irrigação determinada pela artéria celíaca nos papagaios segue o que é proposto para aves de outros gêneros, apresentando divergências como ausência das artérias vesicular e ileocecal, bem como da vesícula biliar e ceco. _________________________________________________________________________________ ABSTRACTThis research was performed aiming to describe the origin and the distribution of the celiac artery in 20 blue fronted amazon (Amazona aestiva), through the completion of their circulatory system with an aqueous solution of colored latex, followed by fixation in formol for later dissection of the collateral branches. The first branch emitted the proventricular dorsal artery that headed to the ventricle as gastric dorsal artery and next emitted the proventricular ventral artery which originated on the celiac artery in 85% of the cases and in 15% had its origin on the left branch of the celiac artery. In 25% of the cases the splenic artery was emitted before the bifurcation on left and right branches. The left branch was responsible for the origin of the proventricular branches, piloric branches, splenic artery and proventricular artery, which emitted branches to the proventricle and esophagus. The celiac artery also emitted the gastric ventral artery and left gastric. The right branch emitted splenic arteries (that varied from a number of seven); duodenal bound for the more caudal segment of the ascendant segment of the duodenum and the right hepatica to the right liver lobe. On its terminal segment the right branch was divided into right gastric arteries to the ventricle and pancreaticduodenal to the pancreas, ascendant and descendant braces of the duodenum and to the cranial segments of the ileum and caudal of the jejune. The irrigation provided by the celiac artery in parrots remains the same as described for other bird genders showing as divergences: the lack of vesicular arteries and ileocecal as well the gall bladder and the cecos