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Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University | Cruz-Suarez D.,Juarez Autonomous University of Tabasco
Journal of Mathematical Analysis and Applications | Year: 2017

This work concerns with Markov chains on a finite state space, which is endowed with a cost function. The evolution of the chain is observed by an agent with constant risk-sensitivity and, assuming that the state space is a communicating class, the relation between the risk-sensitive discounted and average performance criteria is studied. It is proved that, as the discount factor increases to 1, an appropriate normalization of the discounted value function converges to the average cost. Also, it is shown that if the classical normalization used in the risk-neutral case is applied in the risk-sensitive context, then the normalized discounted value function converges to an arithmetic mean of the average cost. © 2017 Elsevier Inc.

Mellado M.,Antonio Narro Agrarian Autonomous University
Rangeland Journal | Year: 2016

Field studies characterising the forage resources of mixed-breed goats on Chihuahuan Desert rangelands were reviewed and the principal sources of variation in their diet choices discussed. Goats eat a varied diet comprising at least 126 plant species in this landscape. Goats are highly selective feeders, changing their diet from predominantly forbs (8-64%) to browse (35-88%). Graminoids make up only ∼5% of the diet, but grasses could be important dietary components on rangelands in good condition. Feed intakes range between 0.8% and 3.4% of bodyweight, depending on the season. DM digestibility of forage selected by goats ranges between 44% and 65%. Annual crude protein (CP) in forages selected by goats varies from 80 to 160 g CP kg-1 DM. Overall, pregnant and lactating goats manage to ingest food that contains higher amounts of CP and lower amounts of cell wall than non-pregnant, non-lactating goats. Goats not adapted to severe shortage of forage select a diet that does not match their nutritional requirements and fetal losses occur. Goat kids select higher quality diets than do mature goats (94.5 vs 88.5 g CP kg-1 DM). Granadina goats eat ∼20% more shrubs, including 3-fold more Larrea tridentata (DC) Cav., than Nubian goats. Goats with severely eroded incisors avoid grasses, focusing on tender-leaved shrubs. During the rainy season, bucks select mainly shrubs (78% of the diet) and avoid grasses (1.7% of the diet), whereas does rely heavily on forbs (about one-third of their diet). Alternating use of grazing grounds increases shrub ingestion by 25%. No evidence exists indicating that food choice by goats in this arid environment is biased towards forages with lower secondary compounds. It is concluded that the flexible, broad-scale and opportunistic feeding behaviour of goats make them an effective animal to sustainably exploit the forage resources of the Chihuahuan Desert. © 2016 Australian Rangeland Society.

Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University
Kybernetika | Year: 2010

This work is concerned with the eigenvalue problem for a monotone and homogenous self-mapping / of a finite dimensional positive cone. Paralleling the classical analysis of the (linear) Perron-Frobenius theorem, a verifiable communication condition is formulated in terms of the successive compositions of /, and under such a condition it is shown that the upper eigenspaces of / are bounded in the projective sense, a property that yields the existence of a nonlinear eigenvalue as well as the projective boundedness of the corresponding eigenspace. The relation of the communication property studied in this note with the idea of indecomposability is briefly discussed.

Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University | Hernandez-Hernandez D.,Research Center en Matematicas
Mathematics of Operations Research | Year: 2011

This work concerns Markov decision processes with finite state space and compact action set. The performance of a control policy is measured by a risk-sensitive average costcriterion and, under standard continuity-compactness conditions, it is shown that the discounted approximations converge to the optimal value function, and that the superior and inferior limit average criteria have the same optimal value function. These conclusions are obtained for every nonnull risk-sensitivity coefficient, and regardless of the communication structure induced by the transition law. © 2011 INFORMS.

Reyes-Valdes M.H.,Antonio Narro Agrarian Autonomous University
Methods in Molecular Biology | Year: 2013

Simple sequence repeats (SSR) are extensively used as genetic markers for studies of diversity, genetic mapping, and cultivar discrimination. The informativeness of a given SSR locus or a loci group depends on the number of alleles, their frequency distribution, as well as the kind of application. Here I describe several methods for calculating marker informativeness, all of them suitable for SSR polymorphisms, proposed by several authors and synthesized in an Information Theory framework. Additionally, free access software resources are described as well as their application through worked examples. © Springer Science+Business Media, LLC 2013.

Sanchez-Pea S.R.,Antonio Narro Agrarian Autonomous University
Florida Entomologist | Year: 2010

The fungus-growing ants (Hymenoptera: Formicidae: Attini) of northeastern Mexico are poorly known. Herein new distributional records in NE Mexico and habitat observations are provided for the fungus-growing ants Apterostigma mexicanum Lattke, Atta texana (Buckley), Cyphomyrmex rimosus (Spinola), Mycocepurus smithii Forel, Mycetosoritis hartmanni Wheeler, Sericomyrmex aztecus Wheeler, Trachymyrmex smithi Buren, and Trachymyrmex turrifex Wheeler.

Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University | Hernandez-Hernandez D.,Research Center en Matematicas
Mathematics of Operations Research | Year: 2016

This work is concerned with finite-state irreducible Markov decision chains satisfying continuity-compactness requirements. It is supposed that the system is driven by a decision maker with utility function U, which, aside mild conditions, is arbitrary, and the performance of a control policy is measured by the long-run average cost criterion induced by U. The main conclusions about this performance index are as follows: (i) the optimal U-average value function coincides with the optimal V -average index for a certain exponential utility V , and (ii) the average criteria associated with U and V have the same class of optimal stationary policies. © 2016 INFORMS.

Delgadillo J.A.,Antonio Narro Agrarian Autonomous University | Velez L.I.,Antonio Narro Agrarian Autonomous University
Animal | Year: 2010

Two experiments were conducted in a subtropical latitude to determine the response of Alpine male goats to a treatment with artificially long days (experiment 1), and the response of anovulatory lactating Alpine does exposed to males treated only with artificially long days (experiment 2). In experiment 1, one group of males was kept under natural photoperiod (n = 4) while another was exposed to 2.5 months of artificially long days (16 h of light/day) from 1 December (n = 4). Plasma testosterone concentrations were determined weekly. Intensity of odor of males was determined every 2 weeks. Sexual behavior of bucks was observed during 3 days about 90 days after the end of the long day treatment. A treatment-by-time interaction was detected for testosterone secretion (P < 0.001). In control males, low plasma concentrations of testosterone were observed from March to June. In contrast, in long-day treated males, high levels of testosterone were observed from March to June (P < 0.05). A treatment-by-time interaction was detected for the intensity of male odor (P < 0.01). The male odor was stronger in long-day treated bucks than in untreated ones from March to June (P < 0.05). The number of ano-genital sniffing, nudging and flehmen was greater in long-day treated males than in untreated ones when exposed to anestrous does (P < 0.05). In experiment 2, one group of males was left under natural photoperiod variations (n = 5) and the other (n = 5) was submitted to the same photoperiodic treatment described in experiment 1. On 3 May, three untreated and three long-day treated males were put in contact with anestrous Alpine does left under natural photoperiod. Fertility was higher in does exposed to light-treated males (36/45, 80%) than those in contact with untreated ones (3/45, 7%; P < 0.05). Prolificacy was similar (P > 0.05) in does exposed to treated (1.8 0.1) and untreated males (1.7 0.3). These results indicate that the sexual activity of Alpine male goats raised in subtropical latitudes can be induced using only artificially long days and that such males are effective in stimulating reproductive activity in anovulatory females in late spring. Copyright © 2010 The Animal Consortium.

Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University
Mathematical Methods of Operations Research | Year: 2010

This note concerns controlled Markov chains on a denumerable sate space. The performance of a control policy is measured by the risk-sensitive average criterion, and it is assumed that (a) the simultaneous Doeblin condition holds, and (b) the system is communicating under the action of each stationary policy. If the cost function is bounded below, it is established that the optimal average cost is characterized by an optimality inequality, and it is to shown that, even for bounded costs, such an inequality may be strict at every state. Also, for a nonnegative cost function with compact support, the existence an uniqueness of bounded solutions of the optimality equation is proved, and an example is provided to show that such a conclusion generally fails when the cost is negative at some state. © 2009 Springer-Verlag.

Cavazos-Cadena R.,Antonio Narro Agrarian Autonomous University
Discrete Event Dynamic Systems: Theory and Applications | Year: 2016

This work concerns semi-Markov chains evolving on a finite state space. The system development generates a cost when a transition is announced, as well as a holding cost which is incurred continuously during each sojourn time. It is assumed that these costs are paid by an observer with positive and constant risk-sensitivity, and the overall performance of the system is measured by the corresponding (long-run) risk-sensitive average cost criterion. In this framework, conditions are provided under which the average index does not depend on the initial state and is characterized in terms of a single Poisson equation. © 2015 Springer Science+Business Media New York

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