نتایج جستجو برای: sexual maturation
تعداد نتایج: 170206 فیلتر نتایج به سال:
The probability that a fish matures at a certain age and length (the so-called probabilistic maturation reaction norm, PMRN) was analysed for a European whitefish Coregonus lavaretus species complex population living in the Austrian pre-alpine Lake Irrsee. Fish length was found to be the only relevant determinant of maturation probability, and females matured at slightly smaller sizes than males.
The evolution of intrinsic growth rate has received less attention than other life history traits, and has been studied differently in plants, homoiotherms, and poikilotherms. The benefits of rapid growth are obvious, so the problems is to explain the costs and tradeoffs that cause organisms to grow below their physiological maximum. Four prevailing themes emerge from the literature: (1) slow g...
This paper considers the length–weight relationship of six out of eight most commonly found fish species inhabiting the Vardar River biotope, the largest riverine system in the central part of the Balkan Peninsula: Alburnoides bipunctatus (Bloch, 1782); Alburnus alburnus (Linnaeus, 1758), Barbus macedonicus Karaman, 1928; Barbus peloponnesius Valenciennes, 1842; Chondrostoma vardarense Karaman,...
In species where parental care occurs primarily via the provisioning of eggs, older females tend to produce larger offspring that have better fitness prospects. Remarkably however, a relationship between age of mother and fitness of offspring has also been reported independently of effects on offspring size suggesting that there may be other factors at play. Here, using experimental matings bet...
BACKGROUND Studies addressing the influence of early sexual maturation on the excess of body weight and height of children and adolescents are scarce. The aim of the study was to analyze the association of sexual maturation with excess body weight and height in children and adolescents. METHODS This was a cross-sectional study performed in Florianópolis city, Brazil, in 2007, with 2339 school...
Two decades ago, the diagnosis of premature sexual development was considered to be simple; the conditions that were recognised were either central precocious puberty, isolated premature thelarche or an adrenal aetiology. The use of pelvic ultrasound and gonadotrophin-releasing hormone (GnRH) analogue treatment was to completely alter our understanding of these disorders. Pelvic ultrasound led ...
Rat somatosensory cortex contains a large sexually monomorphic genital representation. Genital cortex undergoes an unusual 2-fold expansion during puberty. Here, we investigate genital cortex development and female rat sexual maturation. Ovariectomies and estradiol injections suggested sex hormones cause the pubertal genital cortex expansion but not its maintenance at adult size. Genital cortex...
Photoperiod is one of the very important environmental factors that extremely affect growth performance, feeding and reproduction of various fish species. Thus In this research effects of different photoperiod regimes on Caspian Salmon during the premature stage (18 months old at the beginning of experiment) were investigated. One thousand liter tank with 20 premature fishs were allocated for e...
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