Predicting volleyball serve-reception at group level

In a group-serve-reception task, how does serve-reception become effective? We addressed “who” receives/passes the ball, what task-related variables predict action mode selection and whether the action mode selected was associated with reception efficacy. In 182 serve-receptions we tracked the ball and the receivers’ heads with two video-cameras to generate 3D world-coordinates reconstructions. We defined receivers’ reception-areas based on Voronoi diagrams (VD). Our analyses of the data showed that this approach was accurate in describing “who” receives the serve in 95.05% of the times. To predict action mode selection, we used variables related to: serve kinematics, receiver’s movement and on-court positioning, the relation between receiver and his closest partner, and interactions between receiver-ball and receiver-target. Serve’s higher initial velocities together with higher maximum height, as well as smaller longitudinal distances between receiver and target increased the chances for the use of the overhand pass. Conversely, decreasing alignment of the receiver with the ball and the target increased the chances of using the underhand-lateral pass. Finally, the use of the underhand-lateral pass was associated with lower quality receptions. Behavioural variability’s relevance for serve-reception training is discussed.     

Understanding productivity dynamics: A task taxonomy approach

As job markets have been polarizing, firms have been changing their labor inputs. By using matched employer–employee data for Portugal, we examine whether labor market polarization has occurred within or across firms and how labor input upgrades have contributed to overall productivity growth. We develop a firm taxonomy based on worker's occupational data. Firms can be focused on one task – Abstract, Manual or Routine – on a combination of tasks, or none. Results show that Abstract firms are the most productive and their share has increased over time. Manual firms, the least productive, have had a stable share throughout the period. Routine firms have seen their share decline over time. The dynamic decomposition of the estimated productivity reveals that productivity growth is propelled by increased market shares of the most productive incumbents and exiting of the least productive, especially for Abstract firms. Notwithstanding these productivity growth drivers, they fail to avert the productivity stagnation observed in Portugal between 2004 and 2009 due to the overall decline in productivity of incumbent firms, especially Routine. We discuss the policy implications of our results which are relevant to other European economies also lagging behind in terms of knowledge and innovation capabilities.     

Curative role of pantothenic acid in brain damage of gamma irradiated rats

Radiation induced brain damage is associated with impairment of mitochondrial functions, variations in the level of neurotransmitters, and oxidative stress. Mitochondrial function is closely linked to the level of neurotransmitters since the precursors are supplied by the Kreb’s cycle intermediates. The objective of this study was to evaluate the influence of pantothenic acid, an essential component in the synthesis of Coenzyme A (CoA), on the activity of the Krebs cycle enzymes, isocitrate dehydrogenase (IDH), α-ketoglutarate dehydrogenase (α-KGDH), and succinate dehydrogenase (SDH); the level of aspartic, glutamic and GABA; the activity of transaminases, and oxidative stress, in the cerebrum of γ-irradiated rats. Pantothenic acid (26 mg/Kg) was orally administered to the rats, 2 h after irradiation and during the following 5 days. Animals were sacrificed the 7th day post-irradiation. The exposure of male albino rats to γ-rays (5 Gy) has triggered oxidative stress notified by a significant elevation in the level of malondialdehyde (MDA), an end product of lipid peroxidation, associated to a significant decrease in the content of phospholipids, and the antioxidant compound glutathione (GSH). The activity of IDH, α-KGDH, and SDH, has significantly decreased, while the level of aspartic, glutamic and GABA has significantly increased. In parallel to these changes, the activity of alanine and aspartate transaminase has significantly increased, compared to their values in the control rats. Pantothenic acid treatment, has significantly attenuated oxidative stress; enhanced the activity of IDH, α-KGDH, and SDH; minimized the increase in the level of amino acids and the activity of transaminases, compared to their values in the cerebrum of irradiated rats. In conclusion, pantothenic acid could improve the level of neurotransmitters amino acids, which depends on the enzymatic activities of Krebs cycle and linked to oxidative stress.     

Sexualities,teenage pregnancy and educational life histories in Portugal: experiencing sexual citizenship?

This article focuses on Portuguese working-class teenage girls’ voices and experiences concerning sexuality and pregnancy. Within a sociological, feminist and educational framework, it explores the girls’ perspective on sexual and intimate citizenship as evidence of fairer forms of regulation of teenage sexualities. Through building life histories of three pregnant and teenage mothers, this article aims to understand how girls rehearse and live out their sexualities and pregnancies as well as listen to their voices and recognise their demand for inclusion and respect. Gender power relations emerge as central in configuring girls’ pathways and shed light on youth pregnancy.     

Using learning analytics in the Amazonas: understanding students’ behaviour in introductory programming

Tools for automatic grading programming assignments, also known as Online Judges, have been widely used to support computer science (CS) courses. Nevertheless, few studies have used these tools to acquire and analyse interaction data to better understand the students’ performance and behaviours, often due to data availability or inadequate granularity. To address this problem, we propose an Online Judge called CodeBench, which allows for fine-grained data collection of student interactions, at the level of, eg, keystrokes, number of submissions, and grades. We deployed CodeBench for 3 years (2016–18) and collected data from 2058 students from 16 introductory computer science (CS1) courses, on which we have carried out fine-grained learning analytics, towards early detection of effective/ineffective behaviours regarding learning CS concepts. Results extract clear behavioural classes of CS1 students, significantly differentiated both semantically and statistically, enabling us to better explain how student behaviours during programming have influenced learning outcomes. Finally, we also identify behaviours that can guide novice students to improve their learning performance, which can be used for interventions. We believe this work is a step forward towards enhancing Online Judges and helping teachers and students improve their CS1 teaching/learning practices.     

Disclosing biology teachers’ beliefs about biotechnology and biotechnology education

Teachers have been shown to frequently avoid addressing biotechnology topics. Aiming to understand the extent to which teachers’ scarce engagement in biotechnology teaching is influenced by their beliefs and/or by extrinsic constraints, such as practical limitations, this study evaluates biology teachers’ beliefs about biotechnology and biotechnology teaching. The findings of a survey administered to 93 secondary school teachers reveal that, in spite of holding positive beliefs about biotechnology, teachers overestimate the obstacles presented at biotechnology teaching, particularly concerning material and resource limitations. Implications of these findings for teacher training program design are discussed.