ependymomas are glial tumors originate from ependymal cells lining the ventricles and the central canal of the spinal cord. two thirds of ependymomas arise in the infratentorial or intraventriclesandone-third aredetected in supratentorial area. however supratentorial “cortical” ependymomas are veryuncommon. ependymomas are usually infratentorial, intraventricular tumor, including 2–9% of all ce...

We define and study the 2-category of torsors over a Picard groupoid, a central extension of a group by a Picard groupoid, and commutator maps in this central extension. Using this in the context of two-dimensional local fields and two-dimensional adèle theory we obtain the two-dimensional tame symbol and a new proof of Parshin reciprocity laws on an algebraic surface.

Given a finite metacyclic group G, a central extension F having the projective lifting property over all fields is constructed. This extension and its group rings are used to investigate the faithful irreducible projective representations of G and the fields over which they can be realized. A full description of the finite metacyclic groups having central simple twisted group rings over fields ...

considering the importance of extension agent as the mediator between farmers and experts, and their effective role in the transfer of knowledge and technology to farmers with the aim of achieving a sustainable agriculture system, the main purpose of this research was to analysis of the affecting factors on improvement of performance of extension agent from the farmers’ viewpoint in zahak towns...

An extension L/K of skew fields is called a leftpolynomialextension with polynomial generator 0 if it has a left basis of the form 1, i3, ti’, , Bnm’ for some n. This notion of left polynomial extension is a generalisation of the notion of pseudo-linear extension, known from literature. In this paper we show that any polynomial which is the minimal polynomial over K of some element in an extens...

The aim of this research was to investigate this research was to investigate the relationship between Agricultural Information System (AIS) members' viewpoint towards organic products and their environmental in central District of Boyer- Ahmad County. The research population included researchers, extension agents and contact farmers of the study area and based on this population numbers, the sa...

BACKGROUND The indications for elective bilateral central node dissection for patients with unilateral papillary thyroid carcinoma (PTC) who are clinically node negative are still not verified. We investigated the predictive factors of lymph node metastasis and formulated guidelines for surgical extent. METHODS From 2004 to 2009, 325 patients diagnosed with unilateral PTC who had undergone to...

diversity, accessibility and reliability are the three main factors governing the adoption of information sources by farmers in rural areas. based on the research hypothesis, the existing knowledge and information delivery system in the agricultural sector, functions far below the ever changing nature and tangible needs of existing farming systems. the main objective in this study is to determi...