Internal categories as models of homotopy types

A homotopy n-type is a topological space which has trivial homotopy groups above degree n. Every space can be constructed from a sequence of such homotopy types, in a sense made precise by the theory of Postnikov towers, yielding improving `approximations' to the space by encoding information about the first n homotopy groups for increasing n. Thus the study of homotopy types, and the search for models of such spaces that can be fruitfully investigated, has been a central problem in homotopy theory. Of course, a homotopy 0-type is, up to weak homotopy equivalence (isomorphism of homotopy groups), a discrete set. It is well-known that a connected 1-type can be represented, again up to weak homotopy equivalence, as the classifying space of its fundamental group: this is the geometric realization of the simplicial set that is the nerve of the group regarded as a category with one object. Another way to phrase this is that the homotopy category of 1-types obtained by localizing at maps which are weak homotopy equivalences | formally adding inverses for these | is equivalent to the skeleton of the category of groups. In [Mac Lane and Whitehead] it was proved that connected homotopy 2-types can be modeled, in the sense described above, by crossed modules of groups. A crossed module is equivalently what in [Loday] is called a 1-cat-group, but now often referred to as a cat

Estimation of life expectancy in Sistan and Baluchestan province, Iran

Background: Life expectancy deals with the overall level of population health thoroughly considering the effect of mortality. Life expectancy is defined as the expected number of years of life remaining at a given age of people who living in a specific country. This study aimed to estimate life expectancy for the Sistan and Baluchestan province and all its cities based on gender.Methods: This study is a descriptive analytical study. For the analysis of the objectives the required data are mortality information and population data based on age groups and gender. One of the most applicable and most reputed methods in the life table construction is Chaing's methods and was applied this method to estimate life expectancies.Results: Based on the analysis of mortality data, life expectancy at birth for females and males were estimated of 71.5 (This ratio is the percentage of 12 months. 71.5, i.e. 71 years and 6 months) and 68.2 years respectively, and for both sex combined, 69.7 years. These expected years as life expectancy has various values in the rank for the province's cities. In the descending order  the values of life expectancies are belong to Khash, Chabahar, Zahedan, Sarbaz, Zabol, Saravan, Nikshahr and Iranshahr  cities in the given order. Conclusion:This health indicator has smallest value in Sistan and Baluchestan province in compared to other provinces and whole country as well. To increase life expectancy due to health conditions, economic efficiency and extensive planning by the authorities, planners and policy makers are required.

Die Holzstele der Nehemesbastet aus KV 64

The discovery of a new undecorated tomb in the Valley of the Kings (KV 64) revealed an undisturbed burial of the 22nd dynasty. The sarcophagus of a singer of Amun called Nehemes-Bastet and a painted wooden stela were placed upon a layer of limestone debris that filled the tomb chamber to almost half its height. This article focuses on the stela, which is one of the finest examples of its kind. For the first time the original position of this type of object within the burial assemblage can be documented. The stela shows the lady in a white linen dress in front of a seated falcon-headed god addressing a prayer to several deities. The article presents the iconography, investigates the technique and style of the painting and places this new example within a number of close parallels

EXTRACT OF BARBERRY AS ENTIRELY GREEN CATALYST FOR THE SYNTHESIS OF STRUCTURALLY DIVERSE 3,4,5-SUBSTITUTED FURAN-2(5H)-ONES

An eco-friendly and environmentally benign synthesis of 3,4,5-substituted furan-2(5H)-ones employing Iranian seedless barberry, known as Zereshk, (Berberis integerrima “Bidaneh”, Berberidaceae) as a biocatalyst, was developed. For the fi rst time, we found that the barberry juice could be effectively used for three-component condensation reaction of aldehydes, amines, and dialkyl acetylenedicarboxylates. The merits of this method include the environmentally friendly reaction conditions, simple operation, broad substrate, satisfying yields, and the generation of less waste rather than the conventional chemical reagents