نتایج جستجو برای: annual reproductive cycle
تعداد نتایج: 466005 فیلتر نتایج به سال:
The catfish, H. fossilis were exposed to endosulfan for 30 days at sub-lethal concentration (0.002 ppm) during different phases of its annual reproductive cycle. Its impact on total (TP) and different phospholipids- phosphatidylcholine (PC), phosphatidylserine (PS), phosphatdylinositol (Pl) and phosphatidylethanolamine (PE) were measured in liver plasma and ovary. On pesticide exposure, during ...
We investigated the changes in plasma sex steroid hormones, testosterone (T), estradiol-17β (E2), 17,20β -dihydroxy-4-pregnen-3-one (17α20βP), 11-ketotestosterone (11KT) and cortisol levels from ribbed gunnel, Dictyosoma burgeri in associated with annual reproductive cycle. The gonadosomatic index (GSI) of females increased from November, peaked in February and decreased rapidly from March. The...
The rainbow trout endocrine system is sensitive to changes in annual day length, which is likely the principal environmental cue controlling its reproductive cycle. This study focuses on the endocrine regulation of vitellogenin (Vg) protein synthesis, which is the major egg yolk precursor in this fish species. We present a model of Vg production in female rainbow trout which incorporates a biol...
This article is the first ultrastructural study on the annual oviducal cycle in a snake. The ultrastructure of the oviduct was studied in 21 females of the viviparous natricine snake Seminatrix pygaea. Specimens were collected and sacrificed in March, May, June, July, and October from one locale in South Carolina during 1998-1999. The sample included individuals: 1) in an inactive reproductive ...
The Cape porcupine Hystrix africaeaustralis is a large (12-18 kg) nocturnal hystricomorph rodent occurring throughout southern Africa where it is sometimes used as a source of food and often regarded as a nuisance by crop-producing fanners. They live in family groups, these generally comprising an adult male, adult female and varying numbers of offspring of successive litters. Reproduction is c...
The variety of reproductive processes and modes among coral species reflects their extraordinary regeneration ability. Scleractinians are an established example of clonal animals that can exhibit a mixed strategy of sexual and asexual reproduction to maintain their populations. This study provides the first description of the annual reproductive cycle and embryogenesis of the temperate species ...
Identifying the factors that control population dynamics in migratory animals has been constrained by our inability to track individuals throughout the annual cycle. Using stable carbon isotopes, we show that the reproductive success of a long-distance migratory bird is influenced by the quality of habitat located thousands of kilometres away on tropical wintering grounds. For male American red...
Identifying the factors that control population dynamics in migratory animals has been constrained by our inability to track individuals throughout the annual cycle. Using stable carbon isotopes, we show that the reproductive success of a long-distance migratory bird is influenced by the quality of habitat located thousands of kilometres away on tropical wintering grounds. For male American red...
breast cancer is the most common malignancy in women in many parts of the world. the risk factors for breast cancer cover a broad range of conditions, from age to complex genetic alterations. present data is showing an increase in the annual incidence rates of disease and it is ranked as the first recorded malignancies among iranian women after 1999. to study the association of reproductive and...
Understanding sources of reproductive variation can inform management and conservation decisions, population ecology and life-history theory. Annual reproductive variation can drive population growth rate and can be influenced by factors from across the annual cycle (known as carry-over effects). The majority of studies, however, focus solely on the role of current environmental events. Past ev...
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