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.     

Evaluating Three Dimensions of Environmental Knowledge and Their Impact on Behaviour

Research in Science Education - This research evaluates the development of three environmental knowledge dimensions of secondary school students after participation in a singular 1-day outdoor...     

Improvement of PCR reaction conditions for site-directed mutagenesis of big plasmids

QuickChange mutagenesis is the method of choice for site-directed mutagenesis (SDM) of target sequences in a plasmid. It can be applied successfully to small plasmids (up to 10 kb). However, this method cannot efficiently mutate bigger plasmids. Using KOD Hot Start polymerase in combination with high performance liquid chromatography (HPLC) purified primers, we were able to achieve SDM in big plasmids (up to 16 kb) involving not only a single base change but also multiple base changes. Moreover, only six polymerase chain reaction (PCR) cycles and 0.5 μl of polymerase (instead of 18 PCR cycles and 1.0 μl of enzyme in the standard protocol) were sufficient for the reaction.     

R Tricks for Kids

Real‐world phenomena simulation models, which can be used to engage middle‐school students with probability, are described. Links to R instructional material and easy‐to‐use code are provided to facilitate implementation in the classroom.     

Teaching and Learning Science in Hungary, 1867–1945: Schools,Personalities, Influences

The article provides an overview of the development of teaching science in Hungary during both the time of the dual monarchy and the newly established independent Hungary after 1920. The integration of Hungary into the Austro-Hungarian Monarchy (1867–1918) strengthened the effect of German speaking European science, the results of which were quickly channelled into the Hungarian school system at all levels. The Hungarian Academy as well as the University of Budapest (today Eötvös Loránd University) played a leading role in the ?nationalization” of European science in the educational system. Scientific developments in Hungary strengthened the position of rational and secular thinking in a highly religious society and contributed to the erosion of the mental power of the church tradition, particularly that of the Roman Catholic Church. Toward World War I, influenced by the Protestant Churches, the Jewish tradition, and agnosticism, the public picture of science became more international, occasionally ready to consider challenges of the accepted world view, and sometimes less dogmatic. Leading Hungarian figures with an international reputation who played a decisive role in making science part of Hungarian thinking included the physicists Baron Loránd Eötvös and Sándor Mikola, the mathematicians László Rácz and George Pólya as well as a host of others in related fields. Emigration, mostly Jewish, after World War I, contributed to the curtailment of efforts to teach science effectively as some of the best people left Hungary for, mostly, Germany, Britain, and the United States. However, the interwar school system, the Hungarian version of the German Gymnasium, continued to disseminate scientific thought in Hungarian education. Much of the information was foreign and appeared simply in translation—but an impressive array of indigeneous scientific results paved the way to a larger educated middle class then in the making.