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Bogotá, Colombia

Munoz C. K.S.,University of Granada | Ramos Sandoval O.L.,UAN
International Review of Mechanical Engineering | Year: 2016

Ligaments, also known as “collagenous tissues of parallel fibers”, are structures witha passive behavior, i.e. they do not produce motiondirectly. Ligaments connect bones together to form joints, creating functional units, and ensuring properties such as tensile strength. Moreover, the main functions of ligaments are: increasing the mechanical stability of joints, guiding and limiting the joint movements. In this paper the ligament of a pig was subjected to unidirectional tensile stress, and its behavior was studied. The purpose of this research is to present and discuss the results of the tensile test, for doing it a three-dimensional virtual model of the ligament was used; such model was generated by scanning a normalized sample of the pig’s ligament and consequently analyzed using a finite element method (FEM). As a result it was determined that the upper limit of elongation varies between 10% and 15%, and that the maximum stress is near to 35 MPa, when the crosssection area of the sample has been reduced. © 2016 Praise Worthy Prize S.r.l. - All rights reserved.

Meister C.,Museum dHistoire Naturelle de Geneva | Buta A.,UAN | David B.,University of Burgundy | Tavares T.,UAN
Revue de Paleobiologie | Year: 2011

An original fauna of large sized ammonite is described for the Angolan Cretaceous (Upper Albian - Lower Cenomanian) in the Sumbe area. The stage boundary is precisely stated by the presence of Mortoniceras (Subschloenbachia) aff. perinflatum (Spath), Arestoceras goliath (Haas), Mariella (Mariella) gr. bergeri (Brongniart) for the topmost Albian and of Mariella ( Mariella) gr. oehlerti ( Pervinquière), Mariella ( Mariella) aff. gallienii (Boule, Lemoine & Thévenin) with Sharpeiceras group [S. florencae Spath et de Sharpeiceras aff. schlueteri Hyatt] for the basal Cenomanian. A. goliath (Haas) species, seen in the literature as a nomen dubium, is here rehabilitated and considered as an endemic ammonite from Angola, very common in the Sumbe area. The biostratigraphical framework is correlated with the standard zonation of West Europe and with those of North America and North Africa.

Cruz J.F.,UAN | Rodriguez D.D.,Asociacion Colombiana de Criadores de Ganado Normando | Benavides A.C.,UAN | Clavijo J.A.,UAN
Archivos de Zootecnia | Year: 2013

To characterize the Normando breed in Colombia, the multivariate analysis on 1186 data allowed the identification of four groups within the breed. The minority group was the number 1 (8.2 % of the sampled population), while the larger is group 3 (53.0 % of the population). Adjusted lactation of cows in group 2 averaged 5608.4 kg and reproductive parameters as calving interval (433.4 days) and age at first service (28 months); 80.6 % of animals in this group are under intensive supplemented production systems. In group 3, adjusted lactation was 3317.9 kg, and it had the best reproductive parameters, such as 399.2 days calving interval, and 25.7 months of average age at first service; 48.3 % of the cows belonging to this cluster are under improved extensive production systems, and 49.9 % under intensive systems with supplements. The prevailing (71.9 % of the population) milking system in this group is manual and twice per day.

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