Nous avons mis en tvidence les interactions qui s’ttablissent B longue distance, par des chants en duo, entre douze groupes familiaux de Gibbons (Hylobates lar), en Thai’lande. Les analyses statistiques montrent que les familles rtpondent plus volontiers par un duo B un chant en duo venant d’une famille voisine qu’k un chant en duo venant d’une famille non voisine. Les farnilles voisines se dis...

an r-module m is called epi-retractable if every submodule of mr is a homomorphic image of m. it is shown that if r is a right perfect ring, then every projective slightly compressible module mr is epi-retractable. if r is a noetherian ring, then every epi-retractable right r-module has direct sum of uniform submodules. if endomorphism ring of a module mr is von-neumann regular, then m is semi-...

Motivated by comparative genomics, Chen et al. [9] introduced the Maximum Duo-preservation String Mapping (MDSM) problem in which we are given two strings s1 and s2 from the same alphabet and the goal is to find a mapping π between them so as to maximize the number of duos preserved. A duo is any two consecutive characters in a string and it is preserved in the mapping if its two consecutive ch...

An astonishing one-third of the world’s population is infected with the bacterium that causes tuberculosis (TB), Mycobacterium tuberculosis. In most people it remains inactive or latent but in about 10% of people an active case of TB disease will develop within their lifetime. Simple antibiotics can prevent and treat most of these cases, yet 8-10 million people develop an active TB infection an...

‎‎we exhibit an explicit construction for the second cohomology group‎ ‎$h^2(l‎, ‎a)$ for a lie ring $l$ and a trivial $l$-module $a$‎. ‎we show how the elements of $h^2(l‎, ‎a)$ correspond one-to-one to the‎ ‎equivalence classes of central extensions of $l$ by $a$‎, ‎where $a$‎ ‎now is considered as an abelian lie ring‎. ‎for a finite lie‎ ‎ring $l$ we also show that $h^2(l‎, ‎c^*) cong m(l)$‎...

The Test-Duo framework is proposed for automating the task of generating functional test cases for execution on an automatic testing platform. With Test-Duo, the tester focuses on the tasks of refining and annotating use cases and preparing test data sets with tool support, leaving the tasks of generating the actual test cases and marshaling their execution to Test-Duo. The generated test cases...

we introduce the notion ofstrongly $alpha$-reversible rings which is a strong version of$alpha$-reversible rings, and investigate its properties. we firstgive an example to show that strongly reversible rings need not bestrongly $alpha$-reversible. we next argue about the strong$alpha$-reversibility of some kinds of extensions. a number ofproperties of this version are established. it is shown ...

in this paper, we introduce a class of rings which is a generalization of reversible rings. let r be a ring with identity. a ring r is called central reversible if for any a,b ∈ r, ab=0 implies ba belongs to the center of r. since every reversible ring is central reversible, we study sufficient conditions for central reversible rings to be reversible. we prove that some results of reversible ri...

in this paper we focus on a special class of commutative local‎ ‎rings called spap-rings and study the relationship between this‎ ‎class and other classes of rings‎. ‎we characterize the structure of‎ ‎modules and especially‎, ‎the prime submodules of free modules over‎ ‎an spap-ring and derive some basic properties‎. ‎then we answer the‎ ‎question of lam and reyes about strongly oka ideals fam...

STATEMENT OF PROBLEM Contemporary pressable and computer-aided design/manufacturing (CAD/CAM) ceramics exhibit good mechanical and esthetic properties. Their wear resistance compared with human enamel and traditional gold based alloys needs to be better investigated. PURPOSE The purpose of this in vitro study was to compare the 2-body wear resistance of human enamel, gold alloy, and 5 differe...