Do school entry laws affect educational attainment and labor market outcomes?

Age based school entry laws force parents and educators to consider an important tradeoff: though students who are the youngest in their school cohort typically have poorer academic performance, on average, they have slightly higher educational attainment. In this paper we document that for a large cohort of California and Texas natives the school entry laws increased educational attainment of students who enter school early, but also lowered their academic performance while in school. However, we find no evidence that the age at which children enter school effects job market outcomes, such as wages or the probability of employment. This suggests that the net effect on adult labor market outcomes of the increased educational attainment and poorer academic performance is close to zero.     

Multi-Agent Architecture for Intelligent Tutoring Systems

This paper shows a multi-agent architecture based on reactive agents for an intelligent tutoring system (ITS). The global system behavior is modeled taking into account the mental models and the cognitive task analysis. We present the basic characteristics of the reactive system in terms of reactive robotics, where they started. Next we introduce some definitions and schemes in order to characterize the multi-agent architecture. Finally, we present an ITS example called Makatsiná Makatsiná means tutor in TOTONACA, a Mexican pre-Spanish language. which teaches the skills necessary to solve a truss analysis problem by the joint method. This domain is an integration skill.     

The Engagement of Transnationals in Mexican University Classrooms: Points of Entry Toward Recognition Among Future English Teachers

For better or worse, English continues to expand as the commonly shared lingua franca throughout the world. With an increasing movement of transnational students—armed with English and flowing across borders—three university professors discuss their pedagogies and ways of knowing as they engage transnational students inside Mexican university classrooms for future teachers of English. Situated at an interior Mexican public university, each of them explores their unique positioning and the ways they taught transnational students. One is a transnational Mexican-American instructor; another is a researcher of transnationalism historically based in the U.S., and the other co-author is a Mexican national who learned English as a second language and has witnessed the rapidly changing population of students in the interior of Mexico. Toward the aim of improving the way transnationals access and experience formal education, they provide recommendations for improving pedagogy and expanding research.     

Regression Analysis and the Sociological Imagination

Regression analysis is an important aspect of most introductory statistics courses in sociology but is often presented in contexts divorced from the central concerns that bring students into the discipline. Consequently, we present five lesson ideas that emerge from a regression analysis of income inequality and mortality in the USA and Canada.     

Effect of different inter-repetition rest intervals across four load intensities on velocity loss and blood lactate concentration during full squat exercise

ABSTRACT

This study aimed to analyze the acute effect of inter-repetition rest (IRR) intervals on mechanical and metabolic response during four resistance exercise protocols (REPs). Thirty resistance-trained men were randomly assigned to: continuous repetitions (CR), 10 s (IRR10) or 20 s (IRR20) inter-repetition rest. The REPs consisted of 3 sets of 6, 5, 4 and 3 repetitions against 60, 70, 75 and 80% 1RM, respectively, in the full squat exercise. Muscle fatigue was assessed using: percentage of velocity loss over three sets, percentage of velocity loss against the ~1 m·s^?1 load (V1 m·s^?1), and loss of countermovement jump (CMJ) height pre-post exercise. Blood lactate was measured before and after exercise. The percentage of velocity loss over three sets and lactate concentration were significantly lower (P < 0.05) for IRR groups compared to CR in all REPs. The CR group showed a significantly higher (P < 0.05) velocity loss against V1 m·s^?1 load and loss of CMJ height pre-post exercise than IRR groups in REP against 60% 1RM. In conclusion, both IRR groups produced a significant lower degree of fatigue compared to CR group. However, no significant differences were found in any measured variables between IRR configurations.     

Jump height loss as an indicator of fatigue during sprint training

This study analysed the acute mechanical and metabolic responses to a sprint training session focused on maintaining maximal speed until a given speed loss was reached. Nine male high-level sprinters performed 60 m running sprints up to a 3% in speed loss with 6 min rests between sets. Mechanical responses (countermovement jump (CMJ) height and speed loss) and metabolic responses (blood lactate and ammonia concentrations) were measured pre-exercise and after each set was performed. Jump height loss showed almost perfect relationships with both lactate (r = 0.91) and ammonia (r = 0.91) concentrations. In addition, nearly perfect relationships were observed for each athlete between CMJ height loss and lactate (r = 0.93–0.99) and ammonia (r = 0.94–0.99). Very large correlations were found between speed loss and lactate (r = 0.83), and ammonia (r = 0.86) concentrations. Furthermore, close relationships were observed for each athlete between speed loss and lactate (r = 0.86–0.99), and ammonia (r = 0.88–0.98). These results suggest that the CMJ test may allow more accurate setting of training loads in sprint training sessions, by using an individualised sprint dose based on mechanical and physiological responses rather than a standard fixed number of sprints for all athletes.     

The asymmetry of pectoralis muscles is greater in male prepubertal than in professional tennis players

It is generally accepted that preadolescents have a limited capacity to develop muscle hypertrophy in response to exercise compared with older populations; however, studies are scarce and conflicting. The main aim of the present study was to assess if playing tennis is associated with the hypertrophy of dominant pectoralis muscles (PM) in professional (PRO) and in prepubescent tennis players (PRE). A secondary aim was to assess if the degree of asymmetry of PM is greater in PRO than PRE. The volume of PM of both sides was determined using magnetic resonance imaging in 8 male PRO (21.9 years), 6 male PRE (11 years, Tanner 1–2) and 12 male non-active controls (6 adults: 23.5 years; and 6 prepubescents: 10.7 years, Tanner 1–2). PRO and PRE had 15 and 30% greater volume, respectively, in the dominant than in the contralateral PM (P?P?=?.34 in adults and 5%, P?=?.17 in children). The degree of side-to-side asymmetry in PM volume was greater in PRE than in PRO (P?相似文献   

Physiological Correlations With Short,Medium, and Long Cycling Time-Trial Performance

Purpose: Several studies have demonstrated that physiological variables predict cycling endurance performance. However, it is still unclear whether the predictors will change over different performance durations. The aim of this study was to assess the correlations between physiological variables and cycling time trials with different durations. Methods: Twenty trained male cyclists (maximal oxygen uptake [VO₂max] = 60.5 ± 5.6 mL/kg/min) performed 4 separate experimental trials during a 2-week period. Cyclists initially completed an incremental exercise test until volitional exhaustion followed by 3 maximal cycling time trials on separate days. Each time trial consisted of 3 different durations: 5 min, 20 min, and 60 min performed in a randomized order. Results: The main results showed that the physiological measures strongly correlated with long cycling performances rather than short and medium time trials. The time-trial mean power output was moderately high to highly correlated with peak power output and VO_2max (r = .61–.87, r = .72–.89, respectively), and was moderately to highly correlated with the lactate threshold Dmax method and second ventilatory threshold (r = .52–.75, r = .55–.82, respectively). Conclusions: Therefore, trained cyclists should develop maximal aerobic power irrespective of the duration of time trial, as well as enhancements in metabolic thresholds for long-duration time trials.     

Effects of volleyball match-induced fatigue on knee joint position sense

Abstract

It has been suggested that a greater number of injuries during the last third of practice sessions or matches could be related to alteration of lower limb neuromuscular control due to neuromuscular fatigue. This fatigue-related effect can be mediated by changes in joint proprioception. In athletes, the use of functional fatigue protocols could have the advantage of mimicking the demands of sporting activity, thus reflecting more specifically the changes in neuromuscular control and proprioception observed in sport settings. The purpose of the present study was to assess the effect of fatigue induced by a volleyball match on knee joint position sense in elite volleyball players. Seventeen female volleyball players aged 18.9±4.2 years from the Portuguese national team volunteered for the study. Knee joint position sense was evaluated by an open kinetic chain technique and active knee positioning, and was reported using absolute, relative, and variable angular errors. Joint position sense measures were obtained before and immediately after a simulated volleyball match of five sets. To ensure that the match was sufficiently intense to induce fatigue, the perceived exertion or exercise intensity was assessed at the end of the match using Borg’ s rating of perceived exertion (RPE) scale. All participants completed the volleyball match (90min duration), reaching or exceeding 15 on the RPE scale (15.59±0.71; range 15–17), equivalent to “hard/heavy work”. After the volleyball match, a significant increase in absolute (2.11°) and relative (1.71°) angular errors was detected. Match-induced fatigue significantly exacerbated the overestimation of the test position. Moreover, the reliability and accuracy in estimating knee angles decreased from rest to the fatigued state, as shown by the increase (264%) in variable error. Our results show that fatigue induced by a volleyball match has a marked effect on knee joint position sense in elite female volleyball players. Knee joint position sense was less accurate and less consistent after the volleyball match. Fatigue induced by a simulated competitive volleyball match resulted in proprioceptive deficits, decreasing sensorimotor system acuity in female volleyball players.     

Análisis de la interacción ambiental en el aula. Una investigación en el parvulario

Resumen

En la perspectiva metodológica de la Psicologia Ecológica y en su consideración de la clase como unidad ambiental, el presente artículo hace referenda a una investigación sobre los diferentes modos de ocupación/interacción de dos grupos de parvulario con características diferenáadas (procedencia social y cultural, ubicación del edificio, actitud pedagógica…) con los equipamientos que conforman en entorno-clase.

La ocupación viene definida por (a) el número de desplazamientos que realiza cada alumno, (b) los objetos a los que se dirige y (c) la significación que va unida a cada desplazamiento.

Las conclusiones derivadas de los resultados obtenidos evidencian diferencias entre los dos grupos en relación (1) con el modo de organización de la clase en función de la actitud pedagógica del profesor (2) con el papel que adquiere la maestra por la referencia del 45% de las interacciones que se originan en cada grupo.