Effects of inspiratory muscle training in professional women football players: a randomized sham-controlled trial

This study was conducted to determine the effects of inspiratory muscle training (IMT) on respiratory and peripheral muscles oxygenation during a maximal exercise tolerance test and on repeated-sprint ability (RSA) performance in professional women football players. Eighteen athletes were randomly assigned to one of the following groups: SHAM (n = 8) or IMT (n = 10). After a maximal incremental exercise test, all participants performed (on a different day) a time-to-exhaustion (Tlim) test. Peripheral and respiratory muscles oxygenation by near-infrared spectroscopy, breath-by-breath ventilatory and metabolic variables, and blood lactate concentration were measured. The RSA test was performed on a grass field. After a 6 week intervention, all athletes were reevaluated. Both groups showed increases in inspiratory muscles strength, exercise tolerance and RSA performance, however only the IMT group presented lower deoxyhemoglobin and total hemoglobin blood concentrations on intercostal muscles concomitantly to an increased oxyhemoglobin and total hemoglobin blood concentrations on vastus lateralis muscle during Tlim. In conclusion, these results may indicate the potential role of IMT to attenuate inspiratory muscles metaboreflex and consequently improve oxygen and blood supply to limb muscles during high-intensity exercise, with a potential impact on inspiratory muscle strength, exercise tolerance and sprints performance in professional women football players.     

Barriers to electronic mail systems in developing countries

Abstract

Proponents of electronic mail systems (EMS) claim that they increase the productivity and efficiency of operations. Their use has mushroomed in the last five years in industrialized nations. The use of such systems in less developed countries is, however, practically nonexistent. This paper examines the barriers to their use in those countries. These barriers are divided into four categories: technical, economic, political, and social. Some strategies for dealing with those barriers are also presented.     

Multilingual language use and television exposure and preferences: The case of Belize 1

This paper discusses the relationship between the language use patterns of multilinguals and their media preferences and exposure. Specifically, it examines the language behavior of multilinguals in Belize where television is available in both English and Spanish. A survey of Belizean high school students conducted in both languages, asked about their sociolinguistic patterns and media preferences and exposure. The results indicate that the frequency of a particular language's use correlates with preferences for and exposure to television in that language. This relationship is more pronounced when specific cultural programming is considered.     

Exposure to Violence Across the Social Ecosystem and the Development of Aggression: A Test of Ecological Theory in the Israeli–Palestinian Conflict

Bronfenbrenner’s (1979) ecological model proposes that events in higher order social ecosystems should influence human development through their impact on events in lower order social ecosystems. This proposition was tested with respect to ecological violence and the development of children’s aggression via analyses of 3 waves of data (1 wave yearly for 3 years) from 3 age cohorts (starting ages: 8, 11, and 14) representing three populations in the Middle East: Palestinians (N = 600), Israeli Jews (N = 451), and Israeli Arabs (N = 450). Results supported a hypothesized model in which ethnopolitical violence increases community, family, and school violence and children’s aggression. Findings are discussed with respect to ecological and observational learning perspectives on the development of aggressive behavior.     

Near-infrared spectroscopy-derived total haemoglobin as an indicator of changes in muscle blood flow during exercise-induced hyperaemia

ABSTRACT

Blood flow changes in response to exercise have been attributed, among other factors, to the effect of vasodilators factors on the microvasculature, suggesting a close relationship between small blood vessels and conducting arteries. The main purpose of this study was to determine the relationship between the changes in near infrared spectroscopy (NIRS)-derived total haemoglobin ([tHb]) and muscle oxygen saturation (SmO₂) signals and femoral artery blood flow in response to resistance exercise at fast- and slow-velocity muscle contraction. The study randomised crossover design included twelve participants. NIRS and blood flow measurements were continuously monitored before, during, and 5 min after the exercise protocol. There was a significant correlation between [tHb] reperfusion slope ([tHb]_slope) and peak blood flow (BF_peak) after slow- and fast-velocity muscle contraction (r = 0.83, p = 0.0008 and r = 0.72, p = 0.0080, respectively). No significant correlation existed between the SmO₂ reperfusion slope (SmO_{2_slope}) and BF_peak after both slow- and fast-velocity muscle contraction exercise (r = ?0.46, p = 0.1253 and r = 0.33, p = 0.2841, respectively). This study demonstrated a strong relationship between the NIRS-derived [tHb] and Doppler ultrasound BF during the recovery period of dynamic resistance exercise at both slow- and fast-velocity contraction.     

The Use of Representations and Argumentative and Explanatory Situations

This paper discusses the use of non-verbal representations in a modelling-based science teaching context, in which argumentative and explanatory situations occur. More specifically, we analyse how the students and teacher use representations in their discourse in modelling activities, and we discuss the relationships between the functions of these representations and the demands of the explanatory and argumentative situations that exist in that classroom. The data were collected by video recording all the classes in which a teaching sequence about intermolecular interactions was used—a topic which the students had not previously studied. In the activities, the students had to create, express, test, and discuss models in order to understand the difference between intermolecular and interatomic interactions, as well as their influences on the properties of substances. Initially, we selected excerpts of the recorded classes in which a non-verbal representation was used. Then, we used criteria to identify the argumentative and explanatory situations (previously defined), and we created categories for the functions of the representations that were used in order to analyse all the identified situations. The analysis supports conclusions indicating the relevance of the use of non-verbal representations in the construction, use, and defence of explanations. As the defence of explanations was the main context in which argumentative situations occurred in this study, our conclusions also indicate the contribution that representations make towards changing the status of the students' explanations.     

The Educational Challenge of Unraveling the Fantasies of Ontological Security

In this article we address the current context of intensified racialized state securitization by tracing its roots to the naturalized colonial architectures of everyday modern life—which we present through the metaphor of “the house modernity built.” While contemporary crises are often perceived to derive from external threats to the house, we argue that in fact these crises are a product of the violent and unsustainable practices that are required in order to build and sustain the house itself. As the structural integrity of the house increasingly comes under strain, there are different possible responses, three of which we review here. We conclude by asking what kind of education might enable us to imagine and practice alternative formations of existence in a context where the house appears to be crumbling, and, indeed, has always been a fantasy.