The pattern of responding after extensive extinction

Extensive extinction greatly reduces response rate and increases the relative frequency of short interresponse times, but does not affect temporal learning or operant response rate. In each of two experiments, 24 rats were trained in a multiple cued interval procedure with three stimuli (noise, light, and clicker) at three intervals (30, 60, and 120 sec). In Experiment 1, after 50 sessions of extinction, response rate decreased from about 25 to 0.5 responses/min, but temporal discriminations were maintained and the initial response gradients in reacquisition had a pattern that corresponded with the original (rather than current) training conditions. In Experiment 2, these results were replicated and extended by examination of the effect of stimulus duration on response patterns during extinction, but its lack of effect on reacquisition. The similarity of the initial performance in reacquisition to the asymptotic performance in acquisition was presumably due to the similarity of context. The individual subject data may be downloaded from www.psychonomic.org/archive.     

Biomechanical analyses of synchronised swimming standard and contra-standard sculling

Synchronised swimming involves a variety of sculling movements essential for body support and propulsion but its study is scarce. We aimed to biomechanically compare standard and contra-standard sculling techniques, and to observe the relationship between measures. Six synchronised swimmers performed two, 30 s maximal intensity, fully tethered standard and contra-standard sculling motions. Kinetic and kinematic data were obtained using a load-cell and underwater cameras, respectively. Force decreased along both techniques’ bouts, but no differences in-between techniques were noted for any kinetic variables. Standard sculling presented a higher cycle rate and a lower elbow mean angle than the contra-standard sculling (2.4 ± 0.3 vs. 2.0 ± 0.2 cycles/s and 134.1 ± 5.8 and 141.5 ± 4.7°, p < 0.05). In the standard sculling, by removing and maintaining the variation between participants (r _w and r, respectively), the absolute mean force was directly related with cycle rate (r _w  = 0.60) and wrist angular velocity during flexion (r = 0.82), while in the contra-standard condition the force was inversely associated with wrist mean angle (r = ?0.95) and directly with hand speed (r _w  = 0.76), and elbow angular velocity (r _w  ≈ 0.60). Therefore, technique learning and training require different attention by coaches and swimmers.     

Carnation Atoms? A History of Nuclear Energy in Portugal

Drawing upon the concepts of civic epistemologies and sociotechnical imaginaries, this article delves into the history of nuclear energy in Portugal, analyzing the ways in which the nuclear endeavor was differently enacted by various sociopolitical collectives – the Fascist State, post-revolutionary governments and the public. Following the 1974 revolution - known as the Carnation Revolution - this paper analyzes how the nuclear project was fiercely contested by a vibrant anti-nuclear movement assembled against the construction of the Ferrel Nuclear Plant, the first sociotechnical controversy in Portugal, paving the way for the emergence of a combative civic epistemology. Supported by semi-structured interviews with scientists, activists and local residents of Ferrel and the analysis of historical material, this article presents the failed Portuguese nuclear endeavor as an emblematic case study to explore the co-production of science and society, in particular the role of revolutionary processes in the unfolding of sociotechnical controversies.     

Investigating the Development of Science-Literate Identities Through a Multicultural Perspective

The complexity of learning science rests in the fact that it not only possesses a unique lexicon and discourse but also that it ultimately entails a way of knowing. This article involves a case study that examines the academic engagement and perceptions of a group (N = 30) of high school students regarding their science literacy practices. These students were participating in an Engaging Latino Communities in Education (ENLACE) program whose purpose is to increase Latina/o high school graduation rates and assist them with college entrance requirements. The students were enrolled in different science classes to fulfill the science requirements for graduation. The primary research question—What kind of science classroom learning environment supports science-literate identities for ENLACE students?—was juxtaposed with a corollary question: What does multicultural education mean for the science classroom? We incorporate Banks's (2016) five dimensions of multicultural education as interpretative lenses. Overall findings suggest that when Latina/o students are engaged in meaningful laboratory investigations and inquiry activities and when the teaching resembles that of culturally responsive instruction, they are more likely to develop a science-literate identity.     

Effect of hand paddles and parachute on backstroke coordination and stroke parameters

Hand paddles and parachutes have been used in order to overload swimmers, and consequently increase the propulsive force generation in swimming. However, their use may affect not only kinematical parameters (average speed, stroke length and stroke rate), but also time gaps between propulsive phases, assessed through the index of coordination (IdC). The objective of this study was to assess the effects of hand paddles and parachute use, isolated or combined, on kinematical parameters and coordination. Eleven swimmers (backstroke 50-m time: 29.16 ± 1.43 s) performed four 15-m trials in a randomised order at maximal intensity: (1) without implements (FREE), (2) with hand paddles (HPD), (3) with parachute (PCH) and (4) with hand paddles plus parachute (HPD+PCH). All trials were video-recorded (60 Hz) in order to assess average speed, stroke rate, stroke length, five stroke phases and index of coordination. When average swimming speed was compared to FREE, it was lower in PCH and HPD+PCH, and higher in HPD. Stroke rate decreased in all overloaded trials compared to FREE. The use of hand paddles and parachute increased and decreased stroke length, respectively. In addition, propulsive phase duration was increased when hand paddles were used, and time gaps shifted towards zero (no time gap), especially when hand paddles were combined with parachute. It is conceivable that the combined use of hand paddles and parachute, once allowing overloading both propulsive and resistive forces, provides a specific stimulus to improve muscle strength and propulsive continuity.     

The geometric curvature of the spine during the sirshasana,the yoga’s headstand

This study analysed the behaviour of the geometric curvature of the spine during sirshasana. The position of dorsal retroreflective markers was computed via stereophotogrammetric analysis in six males and five females (29.4 ± 8.8 years, 63.0 ± 11.4 kg, 1.66 ± 0.08 m [average ± standard deviation]). The spinal points were projected onto the sagittal and frontal planes of the trunk, a polynomial was fitted to the data and the two-dimensional geometric curvature was quantified. The inferior lumbar lordosis decreased compared to the orthostatic position and gait, which may favour the posterior protrusion of the lumbar spinal nucleus pulposus in people with posterior herniation. The lateral deviation at the middle of the thoracic spine increases during sirshasana, which may reflect increased difficulties for postural control and spinal loads. It could be useful for promoting positive spinal structural and functional chronic adaptations for healthy participants, if the yoga programme is carefully planned and the spinal alignment is carefully monitored during a headstand. However, it may aggravate some spinal diseases, especially scoliosis.     

Mechanical Player Load™ using trunk-mounted accelerometry in football: Is it a reliable,task- and player-specific observation?

The aim of the present study was to examine reliability and construct convergent validity of Player Load? (PL) from trunk-mounted accelerometry, expressed as a cumulative measure and an intensity measure (PL · min^–1). Fifteen male participants twice performed an overground football match simulation that included four different multidirectional football actions (jog, side cut, stride and sprint) whilst wearing a trunk-mounted accelerometer inbuilt in a global positioning system unit. Results showed a moderate-to-high reliability as indicated by the intra-class correlation coefficient (0.806–0.949) and limits of agreement. Convergent validity analysis showed considerable between-participant variation (coefficient of variation range 14.5–24.5%), which was not explained from participant demographics despite a negative association with body height for the stride task. Between-task variations generally showed a moderate correlation between ranking of participants for PL (0.593–0.764) and PL · min^–1 (0.282–0.736). It was concluded that monitoring PL^® in football multidirectional actions presents moderate-to-high reliability, that between-participant variability most likely relies on the individual’s locomotive skills and not their anthropometrics, and that the intensity of a task expressed by PL · min^–1 is largely related to the running velocity of the task.     

Interoperability and Information Integration in an Early Online Academic Digital Library of Theses and Dissertations: The Case of BTD

Cooperative organization has been proposed as a means to improve the usefulness of virtual libraries. Information interchange among library and other academic applications is often hindered by the lack of application interoperability. This hindrance may be overcome through the development of standards that allow for digital libraries to exchange and share information with other applications. The Graduate Program in Production Engineering (PPGEP) of the Federal University of Santa Catarina (UFSC) launched its Theses and Dissertations Bank (BTD) in 1995. BTD is possibly the first online academic digital library of theses. From a digital document repository, BTD evolved into a system that combines bibliometry and informetry features. BTD is used by students and faculty in their research activities, but also by decision makers from industry and academia. They use it, respectively, to search for specialists and to measure interest and knowledge interchange among PPGEP research areas. This article presents the history, features, and development prospects for the BTD project. The integration of BTD with other academic applications, especially those of the Brazilian national science and technology platform, is emphasized.     

Development and construct validation of an inventory for assessing the home environment for motor development

A contemporary view of early childhood motor development considers environmental influences as critical factors in optimal growth and behavior, with the home being the primary agent. However, there has been minimal research examining the relationship between motor development and the home. The present study addresses this gap with the goal of creating an innovative parental self-report instrument to assess the quality and quantity of factors (affordances and events) in the home that are conducive to enhancing motor development in children ages 18-42 months. Following initial face validity determination, expert opinion feedback and selective pilot testing, construct validity was examined using 321 Portuguese families. Factor analysis techniques were used to: (a) compare competingf actorial models according to previous theoretical assumptions, and (b) analyze the fit of the preferred model. Of the five plausible models tested, the five-factor solution provided the best fit to the data. Reliability was established through the scale reliability coefficient with a value of .85. The findings of this study suggest that the Affordances in the Home Environment for Motor Development Self-Report is a valid and reliable instrument to assess how well home environments afford movement and potentially promote motor development.