Haemodynamic changes after prolonged water immersion

Abstract

Thermoneutral water immersion increases cardiac preload and changes the neuroendocrine settings of blood volume regulation. The resulting marked diuresis may lead to significant haemodynamic changes after the end of a prolonged water immersion. Ten volunteers underwent 6 h of complete thermoneutral water immersion. Changes in cardiovascular status were assessed 1 h and 16 h after water immersion. Haemodynamic changes were assessed by Doppler echocardiography. Arterial wall distensibility was estimated by pulse wave velocity analysis. One hour after water immersion, mean weight loss was 1.78 kg and urine volume amounted to 1.5 litres. Echocardiographic measurements evidenced a significant decrease in dimensions of the left cardiac chambers and inferior vena cava. The decreased cardiac preload was paralleled by a lower stroke volume and cardiac output. A peripheral vasoconstriction associated with a relative decrease in the lower limb blood flow was evidenced by an increase in carotid-pedal pulse wave velocity and by a decrease in ankle brachial index. Sixteen hours after water immersion, cardiac preload and cardiac output remained below baseline values and peripheral vascular tone was still higher than at baseline. Marked haemodynamic changes had not returned to baseline 16 h after water immersion. There is a need to design fluid-replacement protocols to improve this recovery.     

When teaching style matches students’ epistemic (in)dependence: The moderating effect of perceived epistemic gap

In a 2×2×2 factorial design, 3rd year Romanian psychology students (N=94) were assigned into 2 groups according to the extent to which they acknowledged an epistemic dependence (lowvs. high) toward their professor. They then compared the competence of 3rd year students to that of 1st year or 5th year students. Finally, they were exposed to a persuasive counter-attitudinal message from an epistemic authority, framed in an authoritarian vs. democratic style. The main dependent variable was the influence of the counter-attitudinal message. Results show an interaction between the three variables. No effects were found among students in the upward social comparison condition in which they felt particularly incompetent. The expected interaction between style and dependence was significant in the down ward comparison condition where participants felt more competent than 1st year students. Students high in perceived epistemic dependence were more influenced by the authoritarian style than those low in epistemic dependence. The reverse tended to be true for participants exposed to the democratic style.     

The adverse effects of parents’ school selection errors on academic achievement: Evidence from the Beijing open enrollment program

One major concern with public school open enrollment programs is the potential for parents’ school selection errors to adversely affect their children's academic achievement. In this study of the Beijing middle school open enrollment program, we estimate the degree to which children's school outcomes were negatively affected by the poor choices their parents made during the school selection process. We do this by examining parents’ responses to a survey on school choices combined with actual school applications, school admission records, and High School Entrance Examination test scores for 4717 students entering middle schools in Beijing via randomized lotteries. We find that the children of parents who made judgment errors in school selection were admitted to lower quality schools and achieved lower test scores on the High School Entrance Examination. Parents who had less education, whose children performed at lower levels in primary school, and who were less attentive to teachers’ opinions about schools were more prone to make these errors. Providing assistance to parents, especially those less prepared to make informed choices about school selection, is consequently important for supporting more efficient and equitable open enrollment programs.     

Innovation as a vehicle for improving socially vulnerable groups’ access to basic provisions: A research note on the development of a questionnaire module

Reducing inequality and social exclusion is a challenging task that will require a joint effort by all societal stakeholders, including not-for-profit and for-profit organizations. In order to develop and evaluate policy actions in this area, monitoring the contribution of these for-profit and not-for-profit organizations to a more inclusive society becomes crucial. This research note describes the development, cognitive pretesting, and large-scale empirical testing of a module that can be included in (inter)national innovation surveys. The module measures whether not-for-profits’ and for-profits’ innovation activities improve vulnerable groups’ access to basic provisions. It also provides insights in the main drivers for improving beneficiaries’ access to basic provisions through innovation and in the types and numbers of beneficiaries reached. The module was tested in the context of the Community Innovation Survey in Flanders, Belgium.     

Approche des statistiques en classe de sixième: Analyse de résultats sportifs

Sans résumé     

Gene-environment processes linking aggression, peer victimization, and the teacher-child relationship

Aggressive behavior in middle childhood is at least partly explained by genetic factors. Nevertheless, estimations of simple effects ignore possible gene-environment interactions (G × E) or gene-environment correlations (rGE) in the etiology of aggression. The present study aimed to simultaneously test for G × E and rGE processes between aggression, on the one hand, and peer victimization and the teacher-child relationship in school, on the other hand. The sample comprised 124 MZ pairs and 93 DZ pairs assessed in Grade 1 (mean age = 84.7 months). Consistent with rGE, children with a presumed genetic disposition for aggression were at an increased risk of peer victimization, whereas in line with G × E, a positive relationship with the teacher mitigated the genetically mediated expression of aggression.     

Integration of cardiac responses to serial stimuli after Pavlovian conditioning in rats

The expression of cardiac responses to sequences of two sounds was studied in restrained rats following discriminative trace or delay conditioning. Stimuli paired with a tail shock 10 sec later (CS1) elicited conditioned bradycardia. Unpaired or neutral stimuli (CS0) elicited mostly tachycardia. Rats did not learn to suppress responding to nonreinforced sequences with an interval of 6 sec between sounds. Responses to the second stimulus were significantly augmented following a CS1 stimulus, but not following a CS0 stimulus. Real-time summation of simple responses provided a more complete and quantitative prediction of dual responses than did resetting or facilitation. These results extend the time range over which summation may be observed from less than 2 sec to at least 16 sec. They appear to be inconsistent with models involving competition between unitary representations of stimuli in short-term memory and suggest the existence of multiple stimulus traces with independent time courses.     

Phonological Awareness and Rapid Automatized Naming as Longitudinal Predictors of Reading in Five Alphabetic Orthographies with Varying Degrees of Consistency

ABSTRACT

Although phonological awareness (PA) and rapid automatized naming (RAN) are confirmed as early predictors of reading in a large number of orthographies, it is as yet unclear whether the predictive patterns are universal or language specific. This was examined in a longitudinal study across Grades 1 and 2 with 1,120 children acquiring one of five alphabetic orthographies with different degrees of orthographic complexity (English, French, German, Dutch, and Greek). Path analyses revealed that a universal model could not be confirmed. When we specified the best-fitting model separately for each language, RAN was a consistent predictor of reading fluency in all orthographies, whereas the association between PA and reading was complex and mostly interactive. We conclude that RAN taps into a language-universal cognitive mechanism that is involved in reading alphabetic orthographies (independent of complexity), whereas the PA–reading relationship depends on many factors like task characteristics, developmental status, and orthographic complexity.     

Video games vs. reading and school/cognitive performances: a study on 27000 middle school teenagers

Video games are a very common leisure activity among teenagers and the aim of this study is to analyse their relations with cognitive and school performances. This study is part of a broad survey, conducted on 27,000 French teenagers (14.5?years old) in middle school (9th grade). The survey contained both a questionnaire on leisure activities practised by teenagers and school/cognitive tests: Comprehension tests, Math, School Knowledge, and Reasoning. The activity frequency (‘never’ to ‘every day or almost’) is studied on five kinds of video games (i.e. action/fighting) vs. seven reading activities (i.e. crime/thriller/fantasy). Results show that there are no correlations or very slight ones between Video Games and cognitive/school tests. Reading activities have potentially important associations with cognition and especially school tests. To conclude, video games are primarily recreational activities and the cognitive stimulation they produce is very different from the one involved in specialised academic subjects