Institution
University of Jyväskylä
Education•Jyvaskyla, Finland•
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.
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Papers
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TL;DR: This work builds a model where the carrying capacity for an organism in a given environment results from the evolution of territorial defense effort and the consequent space use, and predicts fixed territory sizes and regulation by floaters.
Abstract: The carrying capacity of an environment is determined partly by how individuals compete over the available resources. To territorial animals, space is an important resource, leading to conflict over its use. We build a model where the carrying capacity for an organism in a given environment results from the evolution of territorial defense effort and the consequent space use. The same evolutionary process can yield two completely different modes of population regulation. Density dependence arises through expanding and shrinking territories if fecundity is low, breeding success increases gradually with territory size, and/or defense is cheap. By contrast, when fecundity is high, breeding success sharply saturates with territory size, and/or defense is costly, we predict fixed territory sizes and regulation by floaters. These “surplus” individuals form a buffer against population fluctuations. Yet floaters can also harm breeder performance, and by comparing population growth of a territorial popul...
152 citations
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TL;DR: This article examined the longitudinal predictors of nonword decoding, reading fluency, and spelling in three languages that vary in orthographic depth: Finnish, Greek, and English, and found that the model for non-word decoding in Greek was similar to that of Finnish (both have consistent grapheme-to-phoneme mappings).
Abstract: We examined the longitudinal predictors of nonword decoding, reading fluency, and spelling in three languages that vary in orthographic depth: Finnish, Greek, and English. Eighty-two English-speaking, 70 Greek, and 88 Finnish children were followed from the age of 5.5 years old until Grade 2. Prior to any reading instruction, they were administered measures of phonological awareness, letter knowledge, and rapid naming speed. In Grade 2, they were administered measures of nonword decoding, text-reading fluency, and spelling. The results showed that the model for nonword decoding in Greek was similar to that of Finnish (both have consistent grapheme-to-phoneme mappings) while the model for spelling in Greek was similar to that of English (both have some inconsistent phoneme-to-grapheme mappings). In addition, the models for nonword decoding and spelling in Finnish were similar, because Finnish is consistent in both directions. Letter knowledge dominated the prediction in each language. The predictable role of orthographic consistency on literacy acquisition is discussed.
152 citations
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TL;DR: The authors investigated the extent to which the appraisal of work-related goals in terms of their importance, level of achievement, and positive emotions would predict young adults' subsequent success in finding a job after graduation from vocational school and how their success in dealing with this transition would predict how they reappraise their goals later on.
152 citations
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TL;DR: Exhausting stretch-shortening cycle exercise induced local muscle impairment, which resulted in modulation of the reflex and stiffness interaction in the drop jump as well as compensation by central motor command.
Abstract: The purpose of the present study was to investigate the effect of strenuous stretch-shortening cycle exercise on the relationship between reflex and stiffness regulation during the drop jump. Ten healthy male subjects performed submaximal stretch-shortening cycle exercise on a special sledge apparatus. Exhaustion occurred on average within 3 min. A drop jump test from a 50-cm height was performed immediately before and after the sledge exercise, as well as 2 h, 2 days and 4 days later. The fatigue exercise showed relatively high blood lactate concentrations 12.5 (SD 2.6) mmol·l−1 and a 2-day delayed increase of serum cretaine kinase concentration. In drop jumps, the short latency M1 component of the vastus lateralis muscle electromyogram (EMG) response showed a continuous decline throughout the entire follow-up period after fatigue (NS), whereas the medium latency EMG component increased 2 days after the postfatigue sessions (P < 0.05). Immediately after the fatigue exercise a positive correlation (P < 0.05) was found between the changes in the short latency EMG response and in the amount of knee joint stiffness during the early post-landing phase of the drop jump. This suggests that the M1 response was closely related to the stiffness changes during the initial braking phase of the drop jump. Increase of creatine kinase concentration on the 2nd day correlated negatively with the changes in the drop jump performance (P < 0.05). Since the short latency EMG component has almost recovered on the 2nd day, impairment of the mechanical function of the muscle might have taken place. In conclusion, exhausting stretch-shortening cycle exercise induced local muscle impairment, which resulted in modulation of the reflex and stiffness interaction in the drop jump as well as compensation by central motor command.
152 citations
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TL;DR: Vitamin D deficiency is very common in Finnish young men in the winter, and it may have detrimental effects on the acquisition of maximal peak bone mass, as well as prophylaxis for osteoporosis.
Abstract: Severe vitamin D deficiency causes rickets, but scarce data are available about the extent to which vitamin D status determines the development of the peak bone mass in young adults. Our aim was to evaluate the prevalence of vitamin D deficiency [serum 25-hydroxyvitamin D (25-OHD) less than the lower limit of the reference range of 20-105 nmol/liter] and the relationship between vitamin D status and peak bone mass among young Finnish men. A cross-sectional study of determinants of peak bone mass with data on lifestyle factors collected retrospectively was performed in 220 young men, aged 18.3-20.6 yr. One hundred and seventy men were recruits of the Finnish Army, and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content, bone mineral density, and scan area were measured in lumbar spine and upper femur by dual energy x-ray absorptiometry. Serum 25-OHD concentrations were followed prospectively for 1 yr. In July 2000, only 0.9% of the men had vitamin D deficiency, but 6 months later, in the winter, the respective percentage was 38.9%. After adjusting for age, height, weight, exercise, smoking, calcium, and alcohol intake, there existed a positive correlation between serum 25-OHD and bone mineral content at lumbar spine (P = 0.057), femoral neck (P = 0.041), trochanter (P = 0.010), and total hip (P = 0.025). The correlation coefficients for the bone mineral densities at the four measurement sites were 0.035, 0.061, 0.056, and 0.068, respectively. No correlation was found to scan area. We conclude that vitamin D deficiency is very common in Finnish young men in the winter, and it may have detrimental effects on the acquisition of maximal peak bone mass. As in Finland vitamin D supplementation to infants is now stopped at the age of 3 yr, it can be asked whether at our latitude it should be continued from that age onward, not for the prevention of rickets, but as prophylaxis for osteoporosis.
152 citations
Authors
Showing all 8239 results
Name | H-index | Papers | Citations |
---|---|---|---|
Brenda W.J.H. Penninx | 170 | 1139 | 119082 |
Mika Kivimäki | 166 | 1515 | 141468 |
Jaakko Kaprio | 163 | 1532 | 126320 |
Marvin Johnson | 149 | 1827 | 119520 |
Stanislas Dehaene | 149 | 456 | 86539 |
Roger Jones | 138 | 998 | 114061 |
Zubayer Ahammed | 129 | 912 | 59811 |
James Alexander | 129 | 886 | 75096 |
Matti J Kortelainen | 128 | 1186 | 80603 |
Madan M. Aggarwal | 124 | 883 | 56065 |
Joakim Nystrand | 117 | 658 | 50146 |
Robert U. Newton | 109 | 753 | 42527 |
Dieter Røhrich | 102 | 637 | 35942 |
Keijo Häkkinen | 99 | 421 | 31355 |
Dong Jo Kim | 98 | 497 | 36272 |