The markedly different mode of mesoderm formation in anuran and urodelan amphibians (which is related to the early double-layered nature of the anuran blastula wall in contrast to its single-layered nature in the urodeles), but particularly the fundamentally different place and mode of origin of the primordial germ cells in the two groups of amphibians, strongly pleads in favour of a very ancie...

The markedly different mode of mesoderm formation in anuran and urodelan amphibians (which is related to the early double-layered nature of the anuran blastula wall in contrast to its single-layered nature in the urodeles), but particularly the fundamentally different place and mode of origin of the primordial germ cells in the two groups of amphibians, strongly pleads in favour of a very ancie...

introduction:artifical sourace of radiation have increased worldwide average annual exposure of mankind and could especially affect rapidly dividing cells in gonads. since, radiation sensitivities of different components of primordial follicles, and the time required for their deplation have not been morphologically eatablished we decided to estimate the time required for depletion of primordia...

Background: Nandrolone decanoate (ND) is an anabolic androgenic steroid (AAS) which influences the ovarian structure and function. We assessed the effects of ND on the ovarian volume, number of primordial follicles, and level of hormones and also evaluated the modulatory effects of gonadotropins on the histopathological changes imposed by the administration of ND. Methods: Six groups of Sprague...

The computation of PBH (primordial black hole) production from primordial perturbations has recently been improved by considering a more accurate relation between the primordial power spectrum and the PBH mass variance. We present here exact expressions which are valid for primordial spectra of arbitrary shape and which allow accurate numerical calculations. We then consider the possibility to ...

In 1992 neurophysiologists [20] found a new type of cells in areas V1 and V2 of the monkey primary visual cortex, which they called grating cells. These cells respond vigorously to a grating pattern of appropriate orientation and periodicity. Three years later a computational model inspired by these findings was published [9]. The study of this paper is to create a grating cell operator that ha...

Received: March 18, 2015; Accepted: March 20, 2015; Published: March 22, 2015 If you read these pages, you certainly know the seminal book by Benoit B. Mandelbrot, The Fractal Geometry of Nature (1982). In his Masterpiece, Benoit provides both a mathematical model and a description for many of the seemingly complex forms and patterns in nature, showing that fractal patterns are extremely famili...