نتایج جستجو برای: reproductive growth

تعداد نتایج: 904739  

2012
R. M. Garcia-Garcia

There is a strong association between nutrition and reproduction. Chronic dietary energy deficits as well as energy surpluses can impair reproductive capacity. Metabolic status impacts reproductive function at systemic level, modulating the hypothalamic GnRH neuronal network and/or the pituitary gonadotropin secretion through several hormones and neuropeptides, and at the ovarian level, acting ...

F. Kaymaram, M. Darvishi M. S. Sadeghi S. A. Hossainy S. A. Talebzadeh

  Reproduction and spawning patterns of the king fish (Scomberomorus commerson) were studied in the Persian Gulf (Hormozgan Province) and Oman Sea from Oct 2006 to Sep 2007. A total of 1120 fish was collected from different landing sites along the Iranian waters. Yearly analysis of the reproductive stages and gonadosomatic index showed a single reproductive cycle beginning in March and continue...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شهرکرد - دانشکده کشاورزی 1391

از آنجا که کیفیت جنین حاصل از بلوغ آزمایشگاهی تخمک (in vitro maturation) در مقایسه با جنین حاصل از تخمک بالغ شده در شرایط طبیعی بدن (in vivo maturation)، پایین تر از حد انتظار است، بهبود مطالعات مربوط به عوامل تنظیمی پتانسیل تکوین تخمک ضروری است. از طرف دیگر پیشگویی و بهبود شایستگی تکوین (developmental competency) تخمک دو مسئله اساسی در تکنیک های تولیدمثلی (assisted reproductive techniques) هست...

2002
Yasunori YOSHIMURA

Integrins are heterodimeric transmembrane glycoproteins involved in cell-cell and cellextracellular matrix adhesion. They also participate in cytoskeletal rearrangement, co-regulation of growth factor activities and activation of signal transduction. This review describes the available information regarding the role of integrins in human reproductive physiology and discusses their clinical impl...

2009
Sébastien Nusslé Christophe N Bornand Claus Wedekind

Size-selective fishing, environmental changes and reproductive strategies are expected to affect life-history traits such as the individual growth rate. The relative contribution of these factors is not clear, particularly whether size-selective fishing can have a substantial impact on the genetics and hence on the evolution of individual growth rates in wild populations. We analysed a 25-year ...

Journal: :African journal of reproductive health 2013
Kimberly Rovin Karen Hardee Aklilu Kidanu

Global climate change is felt disproportionately in the world's most economically disadvantaged countries. As adaption to an evolving climate becomes increasingly salient on national and global scales, it is important to assess how people at the local-level are already coping with changes. Understanding local responses to climate change is essential for helping countries to construct strategies...

Journal: :Proceedings. Biological sciences 2004
N P Lester B J Shuter P A Abrams

We develop a model for somatic growth in fishes that explicitly allows for the energy demand imposed by reproduction. We show that the von Bertalanffy (VB) equation provides a good description of somatic growth after maturity, but not before. We show that the parameters of the VB equation are simple functions of age at maturity and reproductive investment. We use this model to show how the ener...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2008
Andrew H Lee Sarah Werning

Recent histological studies suggest relatively rapid growth in dinosaurs. However, the timing of reproductive maturity (RM) in dinosaurs is poorly known because unambiguous indicators of RM are rare. One exception is medullary bone (MB), which is an ephemeral bony tissue that forms before ovulation in the marrow cavities of birds as a calcium source for eggshelling. Recently, MB also was descri...

Journal: :Theoretical population biology 2014
Devin W Goodsman Barry Cooke David W Coltman Mark A Lewis

As researchers collect spatiotemporal population and genetic data in tandem, models that connect demography and dispersal to genetics are increasingly relevant. The dominant spatiotemporal model of invasion genetics is the stepping-stone model which represents a gradual range expansion in which individuals jump to uncolonized locations one step at a time. However, many range expansions occur qu...

Journal: :Theoretical population biology 2010
Stefano Ghirlanda Magnus Enquist Matjaz Perc

We consider models of the interactions between human population dynamics and cultural evolution, asking whether they predict sustainable or unsustainable patterns of growth. Phenomenological models predict either unsustainable population growth or stabilization in the near future. The latter prediction, however, is based on extrapolation of current demographic trends and does not take into acco...

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