KINEMATIC ANALYSIS OF BASKETBALL SHOOTING. PRELIMINARY RESULTS

INTRODUCTION-Basketball shooting is the most important skill of the game Its teaching methodology is based on permanent adjustment of theoretical sentences of performance and individual characteristics. Development of basketball players needs talent but also technical qualities which is the reason why youngsters must know the basic principles of technique However, ball size, basket height and court dimensions are three variables which can affect the learning process of basketball shooting (Skleryk , 1985). The purpose of the present study is to analyse the effect of ball size on some mechanical parameters of free throw shooting, as performed by eight fourteen-year-old basketball players Two ball sizes were used regular size ball (613 gr weight, 74 cm perimeter) and adapted size ball (608 gr weight, 76.5 cm perimeter). Two video cameras were utilized to recover the videographic material on frontal and lateral views of shooters Three free throws of each player were digitalized and analysed with BIOSIST Based on Satern (1989), six mechanical parameters related to shooter segment were analysed on ball release (shoulder angle, elbow angle, wrist angle, hand height, linear hand velocity and hand angle) The determination of maximum elbow flexion occurring during shooting was another goal. Also, displacement of the centre of gravity and its relationship with support surface was investigated RESULTS-Mean and standard deviation of each parameter per trial digitalized were selected. Higher values of height and angle release were obtained with adapted size ball. It appears that the regular ball needs an increase of linear hand velocity in shooting Differences between intersegmental angles reveal a general tendency for the shooter to employ more force in regular-ball than in adapted-size-ball. Results show a higher flexion of elbow and a higher release elbow angle when the player shoots with a larger ball. Release angle wrist appears less with regular ball which indicates that more work is produced by the shooting hand with adapted-size-ball. Displacement of centre of gravity on the vertical plan was the most significant difference. The difference between initial instant of shooting and the ball release instant is 0.16 (+/-0 12) m with smaller ball and only 0.07 (+/-0.03) m with a larger ball. CONCLUSIONS-Despite the small differences in the quantitative results, this probably indicates that young players transfer lesser energy on regular-ball than on adapted-size-ball. This leads up to the hypothesis that the adaptation of ball size to particular characteristics of each age scale will create better conditions for young players to learn the correct principles of shooting technique REFERENCES Satern,M.;et al. (1989); The Effect of Ball Size and Basket Height on the Mechanics of Free Throw; J. Mov. SI.; 16; 123-137

KINEMATICS IN BASKETBALL SHOOTING - THE INFLUENCES OF BASKET HEIGHT AND BALL SIZE

INTRODUCTION The majority of coaches identify shooting as the most important skill of basketball. This does not preclude the importance of other skills - dribbling, passing or footwork - but only assume that all offensive actions have shooting as their final objective. Coaches have many preocupations about the direction of team's development. Some of them revolve around the effort of teaching and developing the basic skills of offence. At the same time young players must, from an early age, practice their skills in a regular context, in similar conditions to the adult basketball game. In these more demanding conditions the successful execution of basic skills of offence actions, have the tendency to become more difficult for young players. The purpose of the present study was to analyse the effects of basket height and ball size on some mechanical parameters of shooting technique. METHODS Ten thirteen years old right-handed basketball players were the subjects in this study. A total of 11 3 shoots were digitised and analysed in a bidimensional software program named BIOSIST. Two kind of kinematics parameters were considered: instant kinematics parameters, determinate on the instant of ball release, and behaviour kinematics parameters, which are relative to shooting time. Two heights of basket and two sizes of ball were used. RESULTS Results point to significant differences in linear velocity of shooting hand and height of same segment on ball release, when regular and adapted conditions of basket height were compared. Ball size seemed to have more influence on displacement of centre of mass, particularly on its horizontal path during shooting time. Despite the small differences obtained on intersegmental angles, for both conditions of basket and ball, the adapted form of these variables promotes a better quality of execution for the players. CONCLUSION More significant than ball size, the tendency of results reveals that the adaptation of basket height could create an execution in which its characteristics are similar to theoretical models used by coaches. REFERENCES Ferreira, A.P.; Fernandes, 0.; Abrantes, J. (1996); Kinematic Analysis of Basketball Shooting. Prellimhar Results; in, 14th International Symposium on Biomechanics in Sports. Ed. by Joiio M.C.S. Abrantes; Edi~dies F.M.H., Universidade Tdcnica de Lisboa; pp. 47 1-474

The 12 prophets dataset

The "Ajeijadinho 3D" project is an initiative supported by the University of S\~ao Paulo (Museum of Science and Dean of Culture and Extension), which involves the 3D digitization of art works of Brazilian sculptor Antonio Francisco Lisboa, better known as Aleijadinho. The project made use of advanced acquisition and processing of 3D meshes for preservation and dissemination of the cultural heritage. The dissemination occurs through a Web portal, so that the population has the opportunity to meet the art works in detail using 3D visualization and interaction. The portal address is http://www.aleijadinho3d.icmc.usp.br. The 3D acquisitions were conducted over a week at the end of July 2013 in the cities of Ouro Preto, MG, Brazil and Congonhas do Campo, MG, Brazil. The scanning was done with a special equipment supplied by company Leica Geosystems, which allowed the work to take place at distances between 10 and 30 meters, defining a non-invasive procedure, simplified logistics, and without the need for preparation or isolation of the sites. In Ouro Preto, we digitized the churches of Francisco of Assis, Our Lady of Carmo, and Our Lady of Mercy; in Congonhas do Campo we scanned the entire Sanctuary of Bom Jesus de Matosinhos and his 12 prophets. Once scanned, the art works went through a long process of preparation, which required careful handling of meshes done by experts from the University of S\~ao Paulo in partnership with company Imprimate.Comment: Full dataset online at http://aleijadinho3d.icmc.usp.br/data.htm

Recording from two neurons: second order stimulus reconstruction from spike trains and population coding

We study the reconstruction of visual stimuli from spike trains, recording simultaneously from the two H1 neurons located in the lobula plate of the fly Chrysomya megacephala. The fly views two types of stimuli, corresponding to rotational and translational displacements. If the reconstructed stimulus is to be represented by a Volterra series and correlations between spikes are to be taken into account, first order expansions are insufficient and we have to go to second order, at least. In this case higher order correlation functions have to be manipulated, whose size may become prohibitively large. We therefore develop a Gaussian-like representation for fourth order correlation functions, which works exceedingly well in the case of the fly. The reconstructions using this Gaussian-like representation are very similar to the reconstructions using the experimental correlation functions. The overall contribution to rotational stimulus reconstruction of the second order kernels - measured by a chi-squared averaged over the whole experiment - is only about 8% of the first order contribution. Yet if we introduce an instant-dependent chi-square to measure the contribution of second order kernels at special events, we observe an up to 100% improvement. As may be expected, for translational stimuli the reconstructions are rather poor. The Gaussian-like representation could be a valuable aid in population coding with large number of neurons

Frequency independent patterns from double shell lenses fed by leaky wave feeders

This work aims at designing a wideband leaky lens antenna capable of providing frequency independent patterns over a wide frequency band of operation, about one octave, using connected array of leaky slots as lens feeder in presence of a double shell lens. In addition to on-axis feeding, offset feeding is also studied in order to increase the scanning performance of the antenna system within the proposed frequency band of operation. Improvement in terms of pattern stability and scan loss have been demonstrated in the paper.info:eu-repo/semantics/publishedVersio

A review of entrepreneurship and circular economy research: state of the art and future directions

The circular economy (CE) emerged as an alternative model to the linear system to foster sustainable development. Entrepreneurship represents a key factor in capturing new circular business opportunities. Research on circular entrepreneurship remains at an early phase and is correspondingly somewhat dispersed. Thus, the research objective here is to bring entrepreneurship into the focus of discussions on CE through a systematic literature review. In the absence of any systematic review on this theme, this work aims to map the relevant research and identify the themes discussed in the literature straddling entrepreneurship and the CE currently dispersed across the existing literature. Based on a sample of 102 articles collected from the Scopus and Web of Science databases, this approach identified four thematic groups: growing circular SMEs, born circular firms and start-ups, social entrepreneurship in CE, and support ecosystem for circular entrepreneurship. A greater emphasis on the study of growing circular SMEs to the detriment of other groups is observed. Also, research in the field is mainly focused on European countries. We then propose a future research agenda and a conceptual model for the entrepreneurial process in CE as a point of departure for further developing and deepening the literature on circular entrepreneurship.This work is supported by national funds through Fundação para a Ciência e a Tecnologia, I. P. (Grants UIDB/04630/2020 and UI/BD/151029/2021).info:eu-repo/semantics/publishedVersio

Parameter estimation of a pulp digester model with derivative-free optimization strategies

The work concerns the parameter estimation in the context of the mechanistic modelling of a pulp digester. The problem is cast as a box bounded nonlinear global optimization problem in order to minimize the mismatch between the model outputs with the experimental data observed at a real pulp and paper plant. MCSFilter and Simulated Annealing global optimization methods were used to solve the optimization problem. While the former took longer to converge to the global minimum, the latter terminated faster at a significantly higher value of the objective function and, thus, failed to find the global solution.info:eu-repo/semantics/publishedVersio

Using computational modelling to study extensional rheometry tests for inelastic fluids

The present work focuses on the extensional rheometry test, performed with the Sentmanat extensional rheometer (SER) device, and its main objectives are: (i) to establish the modelling requirements, such as the geometry of the computational domain, initial and boundary conditions, appropriate case setup, and (ii) to investigate the effect of self-induced errors, namely on the sample dimensions and test temperature, on the extensional viscosity obtained through the extensional rheometry tests. The definition of the modelling setup also comprised the selection of the appropriate mesh refinement level to model the process and the conclusion that gravity can be neglected without affecting the numerical predictions. The subsequent study allowed us to conclude that the errors on the sample dimensions have similar effects, originating differences on the extensional viscosity proportional to the induced variations. On the other hand, errors of a similar order of magnitude on the test temperature promote a significant difference in the predicted extensional viscosity.This work was funded by FEDER funds through the COMPETE 2020 Program and National Funds through FCT-Portuguese Foundation for Science and Technology under the projects UIDB/05256/2020/, UIDP/05256/2020, CPCA/A2/6202/2020, CPCA_A2_6231_2020, NORTE-08-5369- FSE-000034, under program IMPULSE-Polímeros e Compósitos: Drivers da Inovação Tecnológica e da Competitividade Industrial

Hemangiopericytoma

A propósito de um caso clínico de hemangiopericitoma com localização no membro inferior esquerdo, os autores fazem uma breve revisão desta entidade patológica. Destacam-se as suas principais características clínicas e salienta-se o contributo da arteriografia, no diagnóstico, e tratamento coadjuvante da cirurgia