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Search Results: 1 - 10 of 267533 matches for " Carlos Valencia C "
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Optimum matchings in weighted bipartite graphs
Carlos E. Valencia,Marcos C. Vargas
Computer Science , 2014,
Abstract: Given an integer weighted bipartite graph $\{G=(U\sqcup V, E), w:E\rightarrow \mathbb{Z}\}$ we consider the problems of finding all the edges that occur in some minimum weight matching of maximum cardinality and enumerating all the minimum weight perfect matchings. Moreover, we construct a subgraph $G_{cs}$ of $G$ which depends on an $\epsilon$-optimal solution of the dual linear program associated to the assignment problem on $\{G,w\}$ that allows us to reduced this problems to their unweighed variants on $G_{cs}$. For instance, when $G$ has a perfect matching and we have an $\epsilon$-optimal solution of the dual linear program associated to the assignment problem on $\{G,w\}$, we solve the problem of finding all the edges that occur in some minimum weight perfect matching in linear time on the number of edges. Therefore, starting from scratch we get an algorithm that solves this problem in time $O(\sqrt{n}m\log(nW))$, where $n=|U|\geq |V|$, $m=|E|$, and $W={\rm max}\{|w(e)|\, :\, e\in E\}$.
Forma y Función , 2011,
Abstract: as a social practice, discourse allows for the concrete expression of the opinions and beliefs that a person or group may have regarding a fact, a situation, or another social group. this makes discourse an effective mechanism for socialization, which can be used to reproduce and endorse ideologies, understood as concepts that include a social and a subjective dimension. therefore, while values or ideals are systems of beliefs expressed in tradition, they are also cognitive structures that build individual thought and action patterns. it is precisely this subjective dimension that grants discourse greater power and symbolic efficacy, since the meaning of human experiences is determined by social interactions, which are ultimately communicative acts that take place in the symbolic world of language. thus, discourse and ideology are intimately linked.
Una nueva especie de Hyphessobrycon (Characiformes: Characidae) de la cuenca del río Telembí, vertiente sur del Pacífico, Colombia A new species of Hyphessobrycon (Characiformes: Characidae) from the Telembí River drain- age, Southern Pacific slope of Colombia
Carlos A. García-Alzate,César Román-Valencia,Donald C. Taphorn
Revista de Biología Tropical , 2013,
Abstract: El género Hyphessobrycon, se incluye dentro de la subfamilia Tetragonopterinae. Las especies generalmente son peque as, no sobrepasan los 70mm de longitud estándar, son importantes económicamente como peces ornamentales, con 128 especies validas que se distribuyen desde el sur de México hasta Río de La Plata en Argentina. Se describe una nueva especie de Hyphessobrycon (Characiformes: Characidae) de la cuenca del río Barbacoas, vertiente sur del Pacífico, Colombia, Hyphessobrycon chocoensis de la cuenca del río Telembí, vertiente del Pacífico Colombiano. Las recolectas de los peces fueron realizadas con redes de arrastres y se hicieron en un solo biotopo, zona litoral de remanso y a favor de la corriente. Las medidas de los ejemplares se tomaron punto a punto con un calibrador digital Las observaciones de estructuras óseas y cartílagos se hicieron sobre ejemplares clareados y te idos (C&T). Las relaciones morfométricas entre especies fueron exploradas empleando 21 variables mediante un análisis de componentes principales (ACP). La nueva especie de Hyphessobrycon, H. chocoensis se distingue de sus congéneres no miembros del grupo flammeus por tener una mancha humeral difusa, no tener una mancha oscura en la aleta dorsal o en el pedúnculo caudal. Se distingue de las demás especies del grupo por el número de radios de la aleta dorsal (ii, 8, i), por el número de radios ramificados en la aleta anal (25-26) y por presentar la mancha humeral difusa, se diferencia de H. tortuguerae por el número de dientes en el maxilar (1-2), por el número de escamas pre- dorsales (10-12) y un alto número de escamas entre la línea lateral y la aleta anal (6-7). Hyphessobrycon chocoensis se puede separar de todos los otros Hyphessobrycon conocidos de las cuencas del Pacifico Colombiano por presentar: un alto número de escamas con poros en la línea lateral, por la longitud hocico-aleta dorsal, por la profundidad del pedúnculo caudal y por el diámetro del ojo. Además, se distingue de H. columbianus por la longitud aleta dorsal- aleta anal, por la longitud de la mandíbula superior, por la longitud del hocico. Del mismo modo se diferencia de H. condotensis por tener un alto número de escamas entre la línea lateral y la aleta dorsal, por una mayor cantidad de radios simples en la aleta anal. H. chocoensis se aparta de H. sebastiani por el número de escamas en la parte: lateral del cuerpo y entre la línea lateral y la aleta dorsal. Se incluye una clave taxonómica práctica de las especies presentes en la vertiente del Pacifico de Colombia. The genus Hyphessobrycon is included within t
A simulation-optimization heuristic for configuring a selective pallet rack system
Vélez Gallego,Mario C; Valencia Ramírez,Diego A; Castro Zuluaga,Carlos A;
Ingeniare. Revista chilena de ingeniería , 2012, DOI: 10.4067/S0718-33052012000100003
Abstract: a discrete event simulation-optimization heuristic is presented for configuring a selective pallet rack system. to the rack system under study pallets arrive dynamically over time to be stored for a given period of time. the storage duration, arrival time and pallet height are assumed to be continuous random variables with known density functions. in such a system, if there is no available slot in the rack to store an arriving pallet, it is placed on the floor. the proposed heuristic aims at minimizing the number of racking banks needed so that the long term proportion of pallets that are placed in a rack slot reaches a minimum pre-specified value. the computational experiments conducted suggest that the proposed heuristic effectively solves the problem under study.
El sistema orexinérgico/hipocretinérgico y su rol en los trastornos del sue?o
Valencia A,Mauricio H; Cassiani M,Carlos A; Cardona O,Juan C; Villalobos Talero,Julio;
Revista Salud Uninorte , 2010,
Abstract: orexins or hypocretins are recently described (1998) neuropeptides found in greater density in hypothalamic neurons, wich have been shown to be important for modulating feeding and sleep-wakefulness cycle. orexinergic system has broad projections throughout the length and breadth of the cns specially to monoaminergic centers such as the locus coeruleus, tuberoamilar neclei, raphe nuclei, and ventral tegmental area. initially it was thought a key role of orexin in feedin behavior regulation, however, recent studies give a leading role to these neuropeptides in regulating the sleep-wakefulness cycle, this discovery opens a door to help better understand the operation of an area so important for the homeostasis of the human body, such as the hypothalamus, and gives some basis for a better understanding of the pathogenesis and pathophysiology in relation to eating disorders and sleep. the aim of this paper is to provide an updated review of the morphological and functional aspects that are known so far in relation to these molecules and their relationship with sleep disorders, especially their involvement in narcolepsy.
Muntané S,Amadeo; Valencia C,Carlos; Moro E,María Luisa; Calderón V,Ana;
Revista chilena de radiología , 2006, DOI: 10.4067/S0717-93082006000300006
Abstract: we present the case of a man with history of epistaxis and facial pain. ct showed a destructive mass located in the paranasal sinuses that extends into the rachis channel, aspect that has not been described before. the surgery and pathology study revealed a neuroendocrine carcinoma
Impacto de un Modelo de Movilización Social sobre la Promoción de la Actividad Física en Afiliados al Sistema de Seguridad Social en Salud
Granada-Echeverri,Patricia; Zapata-Valencia,Carlos D.; Giraldo-Trujillo,José C.;
Revista de Salud Pública , 2008, DOI: 10.1590/S0124-00642008000300001
Abstract: objective developing a model of social mobilisation for promoting physical activity as a fundamental health strategy. methods three social health security system groups were considered: people affiliated to the contributive regime, health professionals involved with an eps and public functionaries. people's levels of physical activity, knowledge, beliefs and attitudes and cultural and environmental barriers were determined; health professionals' recommendations and public policy were also taken into account. an intervention model was then constructed on the foregoing information. results the database revealed that most affiliates considered themselves to be active but not in a suitable way; they recognised the benefits of engaging in regular physical activity but they barely considered the possibility of practising it. the main barriers were a lack of self-discipline, lack of time and the need for resting during their free time. a high percentage of health professionals did not recommend it to their patients; most public functionaries stated that physical activity was included in their cities' development strategies. the model's impact was evaluated; it was seen that greater recognition of physical activity was produced in the three groups after applying the model. the concept of recommended time and frequency for physical activity became modified and a greater change in attitudes was produced. however, cultural barriers remained. health professionals presented changes related to their perception of their state of health and they tended to increase their recommendation for physical activity during medical visits. discussion the social mobilisation model proved the efficiency of promoting physical activity for preventing non-transmissible chronic diseases.
Aneurisma aórtico bacteriano por Salmonella spp.
Jiménez,César; Valencia,álex; Jaramilo,Carlos; Correa,Juan Rafael;
Revista Colombiana de Cirugía , 2011,
Abstract: in spite of the great advances in medical science, especially regarding the antimicrobial agents, infection remains an important cause of morbidity and mortality. typhoid fever, which exterminated a major part of the european population in the eighteenth century, continues to be an entity that demands all of our attention so as to avoid its serious complications. the salmonell sp. have the capacity to infect different organs and parts of the body, including the great vessels, where thy affect the intima layer and produce a condition that is called infectious aneurysm that is associated with a mortality rate around 50%. we report the case of an ulcerated bacterial aneurysm in a 62 year old male with previous symptomatology of salmonella spp. infection and positive blood cultures for this microorganism. the patient underwent surgical treatment with resection of the aneurisma and a dacron silver coated prosthesis replacement and a patch of greater omentum. clinical course was satisfactoiry.
Morfogeometría de los peces del género Hyphessobrycon (Characiformes: Characidae), grupo heterorhabdus, en Venezuela
García-Alzate,Carlos A; Román-Valencia,César; González,Melissa I;
Revista de Biología Tropical , 2010,
Abstract: morphogeometry of fishes in the genus hyphessobrycon (characiformes: characidae), heterorhabdus group, from venezuela. hyphessobrycon is the most numerous and morphologically complex genus of characidae, that includes 122 valid species, 17 of which are present in venezuela. different methods have been proposed for species identification within this genus. we present a morphometric analysis for the species hyphessobrycon, heterorhabdus group. a total number of 310 individuals were photographed and analyzed by means of box truss method. the combination of 16 homologous landmarks and the design of box truss yielded 28 measurements. the principal components analysis (pca) indicated that the differences between the species are related to the distance between snout and the supraoccipital (81.7%), and between the supraoccipital and the base of the pectoral fin (11.87%). all species showed allometric growth except for hyphessobrycon tuyensis, which resulted isometric in the box truss i. the partial deformations describe the form differences related to the cephalic region and the body depth. the great body form similarity is related to the phylogeny and biogeography of these species. rev. biol. trop. 58 (3): 801-811. epub 2010 september 01.
Amadeo Muntané S,August Vidal B,Carlos Valencia C,Rosa Cambra M
Revista Chilena de Radiología , 2009,
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