Low energy availability in exercising men is associated with reduced leptin and insulin but not with changes in other metabolic hormones

Low energy availability, defined as low caloric intake relative to exercise energy expenditure, has been linked to endocrine alterations frequently observed in chronically energy-deficient exercising women. Our goal was to determine the endocrine effects of low energy availability in exercising men. Six exercising men (VO_2peak: 49.3 ± 2.4 ml · kg^?1 · min^?1) underwent two conditions of low energy availability (15 kcal · kg^?1 fat-free mass [FFM] · day^?1) and two energy-balanced conditions (40 kcal · kg^?1 FFM · day^?1) in randomised order. During one low energy availability and one balanced condition, participants exercised to expend 15 kcal · kg^?1 FFM · day^?1; no exercise was conducted during the other two conditions. Metabolic hormones were assessed before and after each 4-day period. Following both low energy availability conditions, leptin (?53% to ?56%) and insulin (?34% to ?38%) were reduced (P < 0.05). Reductions in leptin and insulin were independent of whether low energy availability was attained with or without exercise (P > 0.80). Low energy availability did not significantly impact ghrelin, triiodothyronine, testosterone and IGF-1 (all P > 0.05). The observed reductions in leptin and insulin were in the same magnitude as changes previously reported in sedentary women. Further research is needed to understand why other metabolic hormones are more robust against low energy availability in exercising men than those in sedentary and exercising women.     

Policy on ethnic segregation in a system of choice: the case of The Netherlands

This paper examines the implications of the uneven distribution of minority pupils and the Dutch system of choice for policies on ethnic segregation at both the local and school level. The analysis is based on a sample of 27 municipalities serving 23% of all Dutch primary school pupils. Segregation to a large extent can be found in The Netherlands as elsewhere, and the constitutional freedom of education is precisely the factor that places important restrictions on solving this problem adequately. At the local level more than one‐third of all municipalities, for various reasons, do not take any action. Of the others that do take action the majority saddles the schools with the responsibility since the problems are mainly seen as of an educational nature. According to the school principals a percentage of minority pupils exceeding 50‐60% causes ‘white’ parents to leave and they are given every opportunity to do so by the Dutch system of free parental choice. Therefore a radical reorientation is required in the Dutch system of choice in order to address the challenges of ethnic segregation.     

The Dutch policy of integration put to the test: differences in academic and psychosocial development of pupils in special and mainstream education

After several failed attempts to rein in the growth of special education, the Dutch government made a start in 1991 with a policy to accommodate pupils with problems in regular education and to put a stop to the growth of special education. This paper examines a large-scale study conducted by our research group at the University of Amsterdam which attempted to answer the question whether pupils with problems are better off in special education where there are more resources and they can get more attention than in mainstream schools. It was expected that the pupils in special education would do better due to the specialist care and individual attention. However, with a few exceptions, few differences were found when comparable at-risk pupils in regular schools were compared with their counterparts in both types of special schools. There was a conspicuously large measure of variability in both regular and special education. All school types had both at-risk pupils who were doing well from an academic and/or psychosocial perspective and pupils whose progress left much to be desired. There is little evidence to support the idea that at-risk pupils make less progress, in either their academic or psychosocial development, in regular schools compared with pupils in special schools. The general assumption that at-risk pupils will do better in special education does not seem to account for its attractiveness. Contrary to the policy theory, the dual system, as it exists in The Netherlands, does not appear to be an obstacle to the provision of adequate care for pupils with special educational needs. However, the policy to equip regular schools to accommodate this category of pupils appears not to be realized as simply as that. It has not proved possible to demonstrate the effects of the varying levels of specialist help provided by regular schools on the development of at-risk pupils.     

Making the connection: The role of social and academic school experiences in students' emotional engagement with school in post-secondary vocational education

This study examines the emotional engagement with school of a diverse sample of 909 students in post-secondary vocational education in the Netherlands. Using multilevel regression analysis, we assess the role of students' background characteristics and school experiences, and their interaction, in students' emotional engagement with school. At-risk students do not report lower levels of emotional engagement, except for students using (soft)drugs. While Dutch dropout prevention focuses on fostering a sense of belonging through enhancing teacher–student relationships, we do not find a significant role of perceived support from school staff in students' sense of belonging. A good relationship with classmates is more important to engage students in post-secondary vocational education. Perceiving an academic fit is most prominently related to the emotional engagement of vocational students, indicating that a sense of belonging should not only be defined in social, but also in academic terms.     

Decomposing Cross-Country Differences in Skills: Evidence from Four Nordic Countries

This paper performs multivariate analysis of skill differences in four Nordic countries as assessed by the Organisation for Economic Co-operation and Development’s Programme for the International Assessment of Adult Competencies survey of adults aged 16–65. The differences in average skills between Finland and each of the three Scandinavian countries are decomposed into a component that is due to different skill levels in subgroups of the population and a component that is due to differences in the composition of subgroups. The decompositions show that the high Finnish average skill level compared to the three Scandinavian countries can be attributed to the low share of immigrants in Finland and to high scores among Finns with high school and less than high school education. The Finnish average score is pulled substantially downwards as a consequence of the low numeracy skill level among older Finns, which is consistent with an increase in the quantity or quality of Finnish education over time, relative to the other three Nordic countries.     

Acute exercise-induced irisin release in healthy adults: Associations with training status and exercise mode

There is a growing interest in exploring irisin response to acute exercise; however, the associations of acute exercise-induced irisin release with training status and exercise mode are not fully understood. This study was primarily designed to evaluate these associations. Sixteen healthy adults (8 trained versus 8 untrained) underwent a bout of cycling at 80% of maximal oxygen uptake (VO_2max) for 50?min, with blood drawn pre-, 10-, and 180-min post-exercise. Another 17 healthy adults performed 2 bouts of graded exercise (cycling and running) until exhaustion on separate days using a randomized cross-over design, with blood taken pre-, 0-, 10-, and 60-min post-exercise. Circulating irisin, creatine kinase (CK), aspartate aminotransferase (AST), and myoglobin (Mb) were measured, and their respective areas under the curves (AUCs) were calculated. Irisin increased 10-min after 50?min of cycling at 80% of VO_2max, while its changes from baseline to post-exercise and the amount of exercise-induced irisin release (presented as AUC) were comparable between trained and untrained adults (all P?>?.05). Irisin remained elevated 10-min post-exhausting running but decreased towards baseline 10-min post-exhausting cycling. Exhausting running induced an increase in irisin release for the whole course of exercise and recovery periods, but cycling did not. Acute exercise-induced irisin changes seemed not related to changes of CK, aspartate AST, and Mb in general. In conclusion, acute exercise-induced irisin release is not associated with training status but might be affected by training mode. Future studies are required to investigate which exercise mode might be most efficient in altering irisin.     

Inquiring scaffolds in laboratory tasks: an instance of a “worked laboratory guide effect”?

The study explores if established support devices for paper–pencil problem solving, namely worked examples and incremental scaffolds, are applicable to laboratory tasks. N?=?173 grade eight students solved in dyads a physics laboratory task in one of three conditions. In condition A (unguided problem solving), students were asked to determine the mass of an unknown object by applying Hooke’s law. In condition B (laboratory guide), students received a guide which instructed and explained each solution step. In condition C (incremental scaffolds), the solution steps were presented incrementally on learner demand and were preceded by strategic prompts. Dependent variables were learning outcomes (solution, retention, knowledge) and motivational learning experiences (basic needs, situational interest, deeper level processing). The laboratory guide (B) led to better learning outcomes (d?=?0.42) but lower motivation (d?>?0.38) compared to unguided problem solving (A). Incremental scaffolds (C) led to higher motivation (d?>?0.44) but similar learning outcomes compared to a laboratory guide.