Bi-Lipschitz geometry of weighted homogeneous surface singularities

We show that a weighted homogeneous complex surface singularity is metrically conical (i.e., bi-Lipschitz equivalent to a metric cone) only if its two lowest weights are equal. We also give an example of a pair of weighted homogeneous complex surface singularities that are topologically equivalent but not bi-Lipschitz equivalent.Comment: 5 pages. Added result that nonhomogeneous cyclic quotients are not conica

Economia de nado e tempo limite à velocidade mínima de vo2max: novas descobertas

A economia de nado é uma área de investigação que teve como pioneiros, em Portugal, Vilas- Boas (1993) e Alves (1995). Passada uma década, novos momentos experimentais foram realizados e resultados up to date foram obtidos. As mais recentes metodologias foram empregues e, inclusivamente, uma nova área de treino parece ter emergido - o tempo até à exaustão à intensidade de nado correspondente à Potencia Aeróbia, isto é, ao consumo máximo de oxigénio (VO2max)

Determinant kinantropometric factors in swimming

O objetivo deste trabalho é apresentar uma revisão bibliográfica das principais características cineantropométricas do nadador e a forma como estas influenciam a sua prestação na modalidade. As principais conclusões obtidas foram as seguintes: (i) os nadadores são mais altos e pesados do que a população em geral; (ii) os nadadores apresentam um elevado índice envergadura/altura, explicitando valores elevados do diâmetro biacromial e do comprimento dos MS; (iii) verifica-se uma elevada razão entre os diâmetros biacromial e bicristal, traduzindo um fator decisivo na modalidade: a promoção de um coeficiente de arrasto inferior; (iv) foram observados elevados valores de comprimento e superfície dos membros dos nadadores (afetando positivamente a sua capacidade propulsiva); (v) os nadadores de elite apresentam um somatótipo médio ecto-mesomorfo e as nadadoras são centrais ou mesomorfas equilibradas; (vi) como grupo, os nadadores apresentam um maior percentual de massa gorda do que outros desportistas, fator este que poderá beneficiários relativamente à sua flutuabilidade.The aim of this work is to present a bibliographic review, based on the specialized literature, of the kineantropometric characteristics of swimmers and their importance for swimming performance. The main conclusions were: (i) swimmers are taller and heavier than the general population; (ii) swimmers present an high index of arm span/height (explained by a large biacromial diameter and long the upper arm); (iii) high values for the biacromial/bicristal diameter ratio were found, offering a lower drag coefficient; (iv) high length and surface area arm and leg values were observed (which positively influence their propulsion capacity); (v) elite male swimmers presents a ectomorph-endomorph somatotype and elite female swimmers are central or balanced mesomorphs (vi) swimmers exhibit a higher percentage of body mass than other athletes, which may benefit positively their floatation

Relationships between some well known indicators of aerobic resistance of swimmers

The concept of the anaerobic threshold (AT) at swimming velocity corresponding to 4 mmol.l-1 blood lactate concentrations (v4), introduced by Mader et al. (1976) and further developed by following authors, was used by a large number of scientists and swimming coaches for training and diagnostic purposes. Although it's considered a good indicator of aerobic capacity of swimmers, some authors disagree of that fixed value, arguing that the individual AT varies a lot, namely between 2 and 5 mmol.l-1 (Madsen e Lohberg, 1987). The purpose of this study is to verify the adequacy of the v4 in swimming, comparing it with two other valid indicators of the AT: critical velocity (cv) and the mean velocity of the 30 min test (vT30). Subjects were 30 juvenile swimmers of the Porto regional swimming team (with ages between 12 and 15 years). V4 was determined according to the 2 x 400m protocol, being the first repetition performed at 85% of the personal best and the second one at maximum speed (a rest period higher than 30 min was respected between repetitions). Samples of 25 μl of capillary blood were collected at 3, 5 and 7 min of recovery and analysed for blood lactate concentration with an Accusport analyser (Boheringer Manheim). CV was assessed based in the results of maximal tests of 100 e 400m and was considered as the slope of the regression line calculated between the test distances and the respective times. The ratio between the distance achieved and the duration of the test, i.e., 30 min of continuous swimming assessed the vT30. The mean values of the different variables are presented in Table 1. These results showed that the mean values of v3, v4 and v5, cv and vT30 are very similar; only v8 is statistically different of some other parameters (v3, v4, cv and vT30). We can also see strong positive correlation (r³0.91) between all the parameters (with exception of v8) regardless the stronger values between V5 and the other two tests.info:eu-repo/semantics/publishedVersio

Um modelo de caracterização e avaliação ecológica para o planeamento e gestão

Decorrem actualmente na Universidade de Évora diversos projectos de investigação visando o desenvolvimento de metodologias de caracterização e avaliação ecológica com vista ao planeamento e gestão do território. Tais projectos, desenvolvidos a escalas complementares (1:10 000; 1:25 000 e 1:100 000), pretendem via a constituir um quadro metodológico inovador integrando num único plano de caracterização e avaliação, o plano dos sistemas de uso e o plano dos sistemas ecológicos espaciais. A necessidade de um tal sistema integrado justifica-se pela carência de um referencial de caracterização e avaliação do território com vista à articulação od sprocesos de gestão e à promoção dos objectivos de Conservação da Natureza. Com efeito, a necessidade de assegurar a preservação da biodiversidade da globalidade do território impõe uma abordagem à gestaõ do uso deste que assegure que o nível de fragmentação, de conectividade residual, e de complementaridade funcional asseguram as condições para a sustentação viável de meta-populações das espécie-objectivo. Para atingir tal objectivo importa conhecer e conseguir articular nos processos de simulação e gestão, as necessidades, processos e funções dos diferentes usos antrópicos de uma dada região e as necessidades processos, funções e condicionantes espaciais dos diferentes sistemas ecológicos susceptiveis de ocorrerem nessa região ou locais. Interessa igualmente identificat a forma como essa articulação se processa e a sua hierarquização escalar e funcional

Development Of A MATLAB-based Structural Analysis Toolbox For Sensor Placement In A Multi-domain Physical System

This paper discusses a Bond Graph (BG) Structural Analysis Toolbox developed in MATLAB® (MATSAT) that performs causal analysis on the BG and assists the user in the sensor selection process for a multi-domain physical system. MATSAT contains modules for performing the Sequential Causality Assignment Procedure (SCAP) and Causal Path Search (CaPS). The modules can be combined to check for structural properties such as structural observability (SO) for any sensor set. The working of MATSAT is shown for standard systems. Verification of SCAP, CaPS, and necessary and sufficient SO conditions is shown

Predicting the intra-cyclic variation of the velocity of the centre of mass from segmental velocities in butterfly stroke: a pilot study

The purpose of this study was to analyze the relationship between the intra-cycle variation of the horizontal velocity of displacement of the center of mass (dV), the hand’s and feet’s velocity, as well as, to identify the variables that most predict the dV’s, in butterfly stroke. The study was divided in two parts. The aim of Part I was to investigate the behavior of variables in study at slow swimming velocities and the purpose of Part II was the same but at high swimming velocities. 3 male Portuguese swimmers and 1 female swimmer, of international level were studied in Part I. The swimmers were submitted to an incremental set of 200 m butterfly swims. In the Part II, 7 Portuguese male swimmers of national and international level were studied. Each swimmer performed two maximal 25 m butterfly swims. Both protocols were recorded from four different plans, allowing a 3D analysis. It was calculated the dV, the 3D components (Vx, Vy, Vz) of the hand’s velocity and the 2D components (Vx, Vy) of the feet’s velocity. Several variables presented significant correlation coefficients with dV at all selected velocities (high velocity ranged from r = 0.58 for Vx-out to r = 0.82 for Vy-1dwn; slow velocity ranged from r = -0.45 for Vx-1dwn to r=0.73 for Vx-ups; overall velocity ranged from r= 0.34 for Vz-ent to r = 0.82 for Vx-ins). It was also computed a regression model to predict dV. For high velocity (up to 1.75 ± 0.09 m.s-1), the variables that best predict dV were Vy during the first downbeat, Vx and Vy during the arm’s insweep (r2 = 0.93). At slow velocity (up to 1.48 m.s-1), the variables included in the forward step-bystep regression model were Vx during upsweep, Vy and Vx during insweep (r2 = 0.69). For overall velocity, the variables that most fit the regression model were Vx during upsweep, Vy during second downbeat and Vz during entry (r2= 0.94). In order to reduce dV, butterfliers should increase hand’s velocity in all orthogonal components at the end of the underwater path, should increase the vertical velocity durin

Swimming bioenergetics: integrating biomechanical and physiological data into a coherent biophysical model for performance and training

The purpose of the present paper is to synthesise a number of scientific contributions of our research group, into a coherent corpus of knowledge related to swimming biophysics, specially centred on the availability and use of energy in swimming. After an introductory part that intends to underline the relevance of this approach base on the conceptualization of the swimmer, and swimming action itself, as a thermodynamic system and its mechanical output, we will survey a number of studies and respective contributions for a more advanced understanding of swimming performance, that can be transferred into training and enhancement of swimmers’ working capacity. Most of the studies referred were conducted over samples of swimmers of both genders and of different types, from university/participative swimmers to Portuguese elite swimmers, crossing the large population of trained national level swimmers. Those swimmers were studied in the four different competitive swimming strokes, accomplishing progressive protocols based over distances of 200 m. Physiologic parameters like VO2 (and associated ventilatory and respiratory parameters), post exercise capillary blood [La-] peaks, and heart rate, were directly measured. Kinematical parameters were also measured in the different studies, ranging from simple semi-quantitative parameters, like stroke length (SL), and stroke frequency (SF), to more elaborated biomechanical data, like intracyclic speed fluctuations and propulsive segments kinematics. The focus of interest ranged from swimming economy of different strokes and genders (and of different technical alternatives of the same stroke), to the effects over energy cost of intracyclic speed fluctuations. Energetic input determinant factors, like swimming VO2 kinetics, including VO2 slow component, and VO2 time limit, and its determinants, will also be analysed

Surgical Treatment of Intravenous Leiomyomatosis: The Role of the IVC Filter

IntroductionIntravenous leiomyomatosis is a rare, life-threatening intravenous tumor associated with uterine leiomyomata.ReportThis report describes the case of a 45-year-old woman with a history of weakness and exertional dyspnea, and an extensive intracaval mass extending to the right side of the heart. The tumor was successfully removed in a two-stage surgical procedure with an inferior vena cava (IVC) filter deployed before the second stage. An extensive DVT was observed postoperatively.DiscussionSurgical removal is the only effective treatment for intravenous leiomyomatosis, and the rate of recurrence remains unclear. An IVC filter should be placed routinely to prevent postoperative or late (in case of recurrence) pulmonary embolism

Effect of rapid thermal processing conditions on the properties of Cu2ZnSnS4 thin films and solar cell performance

In the present work, we have studied the effect of several sulphurization conditions on the properties of Cu2ZnSnS4 thin films obtained through rapid thermal processing (RTP) of multi-period precursors with 8 periods of Zn/SnS2/CuS. In this study we varied the heating rate, the maximum sulphurization temperature, the time at maximum temperature and the amount of evaporated sulphur. The samples were characterized through scanning electron microscopy, energy dispersive spectroscopy, Raman scattering spectroscopy, X-ray diffraction, photoluminescence and I–V measurements. We have observed that at heating rates above 0.5 1C/s the samples delaminated severely. As a result further tests were carried out at 0.2 1C/s heating rate. The morphological studies revealed that the samples sulphurized at higher temperatures, shorter times and higher amount of evaporated sulphur exhibited larger grain sizes. The structural analysis based on Raman scattering and XRD did not lead to a clear distinction between the samples. Photoluminescence spectroscopy studies showed an asymmetric broad band characteristic of CZTS, which occurs in the range of 1.0–1.4 eV and a second band, on the high energy side of the previous one, peaking at around 1.41 eV. The intensity of this latter band varies from sample to sample revealing substantial differences in their optical properties. This band appears to originate either from the surface of the absorber or from the CdS layer and has a clear correlation with cell efficiency. The higher the intensity of this band the lower the cell efficiency, presumably due to the increase in recombination resulting from CZTS surface decomposition and eventually from the CdS with modified optoelectronic properties. The cell results hint toward a detrimental effect of long sulphuriza-tion times and a positive effect of higher sulphur vapour pressure and higher sulphurization temperature. Solar cell efficiencies improved with increased grain size in the absorber layer. The highest cell efficiency obtained in this study was 3.1%.info:eu-repo/semantics/publishedVersio