Introduction to the Treatment of Non-Linear Effects Using a Gravitational Pendulum     

Klaus Weltner  Antonio Sergio C. Esperidião  Paulo Miranda 《Science & Education》2004,13(7-8):611-629

We show that the treatment of pendulum movement, other than the linear approximation,may be an instructive experimentally based introduction to the physics of non-lineareffects. Firstly the natural frequency of a gravitational pendulum is measured as functionof its amplitude. Secondly forced oscillations of a gravitational pendulum are investigatedexperimentally without limiting amplitudes. By this arrangement new phenomena, thebistability and the jump-effect, can be observed. In the case of bistability the drivengravitational pendulum can oscillate in two different stable modes. Either it oscillateswith a small amplitude and approximately in phase with the exciting torque or it oscillateswith a larger amplitude and approximately anti-phase. The jump effect is the spontaneoustransition from one mode of oscillation to the other. Both effects can be demonstrated andexplained.  相似文献   

On the skewness of journal self‐citations and publisher self‐citations: Cues for discussion from a case study     

Sergio Copiello 《Learned Publishing》2019,32(3):249-258

This paper takes the cue from the case of a retracted paper, cited both by the retraction notice and by an article published later in the same journal. This led to analysis and discussion on the skewness of citations in the journal Sustainability and within Multidisciplinary Digital Publishing Institute (MDPI) journals, particularly investigating self‐citations at journal and publisher levels. I analysed articles published by Sustainability in 2015 and found that self‐citations are higher than expected under a uniform probability distribution. Self‐citations in this journal make a 36% difference to the journal's impact factor. This research raises the question of what citation patterns can be expected as normal, and where the boundary between normal and anomaly lies. I suggest the issue deserves further investigation because self‐citations have several implications, ranging from impact factors to visibility and influence of scientific journals.  相似文献   

Medical publishing and the drug industry: is medical science for sale?     

Sergio SISMONDO 《Learned Publishing》2012,25(1):7-15

The pharmaceutical industry produces an abundance of special‐purpose knowledge, flooding the markets it is most interested in. To gain the largest scientific impact and market value from research, drug company articles placed in medical journals are often written under the names of independent medical researchers. Pharmaceutical company statisticians, reviewers from a diverse array of company departments, medical writers, and publication planners are only rarely acknowledged in journal publications, and key company scientists only sometimes acknowledged. The public knowledge that results from this ghost‐managed research and publication is a marketing tool, providing bases for continuing medical education, buttressing sales pitches, and contributing to medical common sense and further research. In the pharmaceutical industry, knowledge is a resource to be accumulated, shaped, and deployed to best effect. In this paper, I describe this process and discuss ways in which it might be addressed.  相似文献   

Strands of Science Teaching     

Portugal  Khalil Oliveira  Arruda  Sergio de Mello  Passos  Marinez Meneghello 《Science & Education》2022,31(1):149-171

Science & Education - The paper introduces a tool for analyzing the teaching venue (where and how the teaching happens) of science teachers, called Strands of Science Teaching (SST)....  相似文献   

The impact of individual consultation on student ratings of teaching     

Sergio Piccinin  Carolina Cristi  Marcia McCoy 《International Journal for Academic Development》2013,18(2):75-88

Abstract

The present study addressed the impact of individual consultation on teaching improvement as measured by changes in student ratings. Subjects included 91 professors who presented naturally for individual consultation services over a seven‐year period at the teaching centre of a Canadian university. Interventions by the consultant fell into three categories: 1) Feedback‐Consultation, 2) Feedback‐Consultation‐Class Observation, and 3) Feedback‐Consultation‐Class Observation and Student Consultation. End of term student ratings for the course that was the subject of the consultation were compared with student ratings for the same course taught between one and three years prior to the consultation service, and for the same course taught between one to three years following consultation. The results showed that, overall, consultation was effective in improving the quality of the consultees’ teaching, as evidenced by an increase in mean student ratings of instruction. This effect persisted post consultation. Not all intervention groups, however, showed the same pattern of results. Change was evident immediately after the intervention except in the case of brief consultation, although follow‐up data showed improved teaching for the latter group. Control data provided evidence that the change in student ratings post consultation could reasonably be attributed to consultation effects.  相似文献   

Generic Interests and School Subject Choice     

Gerald R. Elsworth  Adrian Harvey-Beavis  John Ainley  Sergio Fabris 《Educational Research and Evaluation》2013,19(3):290-318

While empirical research on school subject preferences and choices has a long history, ‘interest’ has infrequently been invoked as an explanatory construct. Three levels on which interest is conceptualised in educational research are identified. The most general derives from vocational psychology and may be characterised by the themes of Holland’s RIASEC typology. The results of five recent Australian studies in which interests were related to school subject preferences and choices are reviewed, and a series of multi-level models of data from the most recent are presented. The models offer a coherent summary of interest – school subject choice relations and enable accurate estimates to be made of their relative importance across the curriculum fields typically available in the senior secondary years. The consistency in the results of the five studies provides strong support for the hypotheses that school subject preferences and choices are systematically related to interests, and that Holland’s RIASEC themes provide a coherent account of preferences and choices across a broad range of objects, activities and contexts encountered in school and work.  相似文献   

A spectral analysis of team dynamics and tactics in Brazilian football     

Felipe Arruda Moura  Luiz Eduardo Barreto Martins  Ricardo O. Anido  Paulo Régis C. Ruffino  Ricardo M. L. Barros  Sergio Augusto Cunha 《Journal of sports sciences》2013,31(14):1568-1577

Abstract

The purposes of this study were to characterise the total space covered and the distances between players within teams over ten Brazilian First Division Championship matches. Filmed recordings, combined with a tracking system, were used to obtain the trajectories of the players (n = 277), before and after half-time. The team surface area (the area of the convex hull formed by the positions of the players) and spread (the Frobenius norm of the distance-between-player matrix) were calculated as functions of time. A Fast Fourier Transform (FFT) was applied to each time series. The median frequency was then calculated. The results of the surface area time series median frequencies for the first half (0.63 ± 0.10 cycles · min^?1) were significantly greater (P < 0.01) than the second-half values (0.47 ± 0.14 cycles · min^?1). Similarly, the spread variable median frequencies for the first half (0.60 ± 0.14 cycles · min^?1) were significantly greater (P < 0.01) than the second-half values (0.46 ± 0.16 cycles · min^?1). The median frequencies allowed the characterisation of the time series oscillations that represent the speed at which players distribute and then compact their team formation during a match. This analysis can provide insights that allow coaches to better control the team organisation on the pitch.  相似文献   

Creatine Kinase Activity Weakly Correlates to Volume Completed Following Upper Body Resistance Exercise     

Marco Machado  Jeffrey M. Willardson  Dailson P. Silva  Italo C. Frigulha  Alexander J. Koch  Sergio C. Souza 《Research quarterly for exercise and sport》2013,84(2):276-281

In the current study, we examined the relationship between serum creatine kinase (CK) activity following upper body resistance exercise with a 1- or 3-min rest between sets. Twenty men performed two sessions, each consisting of four sets with a 10-repetition maximum load. The results demonstrated significantly greater volume for the 3-min condition (M = 4,156 kg, SD = 867, for 3 min; vs. M = 3,503 kg, SD = 759, for 1 min; p < .001), with no significant differences in delta CK activity between conditions (p = .574). Nevertheless, there was a weak correlation between the delta CK activity and total volume of exercise completed (r = .55 with a 1-min rest, and r =.45 with a 3-min rest). Therefore, the volume following upper body resistance exercise correlates weakly with serum CK levels, irrespective of rest interval length between sets.  相似文献   

R&D subsidies & external collaborative breadth: Differential gains and the role of collaboration experience     

Gary Chapman  Abel Lucena  Sergio Afcha 《Research Policy》2018,47(3):623-636

External collaboration breadth is important for firms to acquire the knowledge needed to innovate. In this paper, we combine cross-sectional and longitudinal data from the Spanish Panel of Technological Innovation Survey (PITEC) to examine the indirect impact of R&D subsidies on firm external collaboration breadth. We contribute to understanding of the indirect impacts of R&D subsidies by first providing strong evidence of an economically significant average positive impact of R&D subsidies on firm external collaboration breadth. Second, our results advance understanding of the differential impacts of R&D subsidies by revealing the vast heterogeneity of the impact at the firm level, where approximately only half of treated firms experience a positive collaboration impact from R&D subsidies, while the remainder experience no impact or a negative effect. Finally, we advance understanding of the characteristics explaining the differential impact of R&D subsidies on external collaboration breadth by utilising the organisational learning literature to demonstrate the important role of firm collaboration experience.  相似文献   

Aerobic exercise training performed by parents reduces mice offspring adiposity     

Paulo Vitor da Silva Romero  Débora Alves Guariglia  Francielli Ferreira Da Rocha  Caroline de Carvalho Picoli  Gustavo Renan Gilio  Gabriel Sergio Fabricio 《Journal of sports sciences》2018,36(14):1578-1585

The present study aimed to determine the effects of physical training performed by parents on mice offspring adiposity. Male and female parents underwent an aerobic training protocol for 7 weeks. The trained and sedentary parents were allowed to mate and the resultant offspring divided in: S (Offspring from Sedentary Parents), T (Offspring from Trained Parents), ST (Offspring from Sedentary Father and Trained Mother) and TS (Offspring from Trained Father and Sedentary Mother). After weaning, offspring was euthanized, blood collected and samples of mesenteric and inguinal fat pads used to isolate adipocytes for morphologic and histological analyses. Lee index, mesenteric fat pad, sum of visceral fat and total fat weight of female T was reduced in comparison to the other groups (p < 0.05). Periepididymal and sum of visceral fat in male T group was also reduced when compared to the other groups (p < 0.05). The diameter of mesenteric and inguinal adipocytes of T group was smaller compared to all groups comparisons for both sexes (p < 0.05). In summary, exercise training performed by parents reduced visceral offspring adiposity, the diameter of subcutaneous adipocytes and improved metabolic parameters associated to metabolic syndrome.  相似文献