University of Jyväskylä

About: University of Jyväskylä is a education organization based out in Jyvaskyla, Finland. It is known for research contribution in the topics: Population & Neutron. The organization has 8066 authors who have published 25168 publications receiving 725033 citations. The organization is also known as: Jyväskylän yliopisto & Kasvatusopillinen korkeakoulu.

Energetic costs of size and sexual signalling in a wolf spider

Abstract: A prerequisite for honest handicaps is that there are significant condition–dependent costs in the expression of sexual traits. In the wolf spider Hygrolycosa rubrofasciata (Ohlert), sexual signalling (drumming) is costly in terms of increased mortality. Here we investigated whether this mortality may be caused by increased energy expenditure. During sexual signalling, metabolic rate was 22 times higher than at rest and four times higher than when males were actively moving. Metabolic rate per unit mass was positively related to absolute body mass during sexual signalling but not during other activities. This positive relationship is novel to any studies of metabolic rates. Indeed, it seems that the largest males can drum only 12 times per minute before reaching the maximum sustainable metabolic rate, whereas the smallest males may drum up to 39 times per minute. However, there is no relationship between body mass and drumming rate, indicating that larger males are able to compensate for the higher cost of drumming. There was a quadratic relationship between relative abdomen mass and overall body mass, which may provide a partial explanation for the increased energy expenditure of largest males while drumming. Altogether, our results indicate that sexual signalling is highly energetically demanding, which may be the main reason for the honesty of signalling in this species. In addition, the energetic costs are surprisingly strongly size dependent, which may compensate any disadvantage of small male size.

Force and EMG power spectrum during eccentric and concentric actions.

Abstract: KOMI, P. V., V. LINNAMO, P. SILVENTOINEN, and M. SILLANPAA. Force and EMG power spectrum during eccentric and concentric actions. Med. Sci. Sports Exerc., Vol. 32, No. 10, pp. 1757–1762, 2000.IntroductionThis study was designed to examine the force and activation levels of elbow flexor muscles durin

Subjective health, symptom load and quality of life of children and adolescents in Europe.

Abstract: Objectives: To examine cross-cultural differences in the prevalence of school children's subjective health types and the pattern of socio-demographic and socio-economic differences.

Maternal transfer of antibodies: raising immuno-ecology issues.

Abstract: The transfer of antibodies from mother to offspring has broad potential implications in evolutionary ecology, from the adaptive value of maternal effects to the role of transgenerational plasticity in host-parasite interactions. Recent contributions have addressed key issues such as environmental and genetic factors affecting the amount of antibodies transferred and whether maternal antibodies affect offspring immunity, but little is still known about the implications of the maternal transfer of antibodies in natural populations. By its position at the crossroads between population ecology, animal science, medicine and epidemiology, current studies of the role of the maternal transfer of antibodies highlight how research in ecological immunology needs to combine functional and evolutionary approaches while also keeping in mind ecological settings.

EMG, muscle fibre and force production characteristics during a 1 year training period in elite weight-lifters

Abstract: The effects of a 1 year training period on 13 elite weight-lifters were investigated by periodical tests of electromyographic, muscle fibre and force production characteristics. A statistically non-significant increase of 3.5% in maximal isometric strength of the leg extensors, from 4841±1104 to 5010±1012 N, occured over the year. Individual changes in the high force portions of the force-velocity curve correlated (p<0.05–0.01) with changes in weight-lifting performance. Training months 5–8 were characterized by the lowest average training intensity (77.1+2.0%), and this resulted in a significant (p<0.05) decrease in maximal neural activation (IEMG) of the muscles, while the last four month period, with only a slightly higher average training intensity (79.1±3.0%), led to a significant (p<0.01) increase in maximum IEMG. Individual increases in training intensity between these two training periods correlated with individual increases both in muscular strength (p<0.05) and in the weight lifted in the clean & jerk (p<0.05). A non-significant increase of 3.9% in total mean muscle fibre area occurred over the year. The present findings demonstrate the limited potential for strength development in elite strength athletes, and suggest that the magnitudes and time courses of neural and hypertrophic adaptations in the neuromuscular system during their training may differ from those reported for previously untrained subjects. The findings additionally indicate the importance of training intensity for modifying training responses in elite strength athletes.