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Zamora-Cardenas A.,Instituto Tecnologico Superior Of Irapuato | Zamora-Cardenas A.,Universidad Michoacana de San Nicolas de Hidalgo | Fuerte-Esquivel C.R.,Universidad Michoacana de San Nicolas de Hidalgo
Electric Power Systems Research | Year: 2011

This paper proposes a practical approach to incorporate Flexible AC Transmission Systems (FACTS) devices into a Weighted Least Squares (WLS) state estimation algorithm. The FACTS devices included in the estimator are the Thyristor Controlled Series Compensator (TCSC), the Static Var Compensator (SVC), and the Unified Power Flow Controller (UPFC). The proposed approach simultaneously upgrades the estimated values of the state variables of these devices and the state variables of the rest of the electric network, for a unified solution in a single-frame of reference. Results are presented to demonstrate the effectiveness of the proposed approach to assess the estimation of the system state and to set the parameters of FACTS controllers for given control specifications. © 2010 Elsevier B.V.

Ramirez-Bautista A.,Autonomous University of the State of Hidalgo | Stephenson B.P.,Mercer University | Lozano A.,Autonomous University of the State of Hidalgo | Uribe-Rodriguez H.,Autonomous University of the State of Hidalgo | Manrique A.L.,Instituto Tecnologico Superior Of Irapuato
Ecology and Evolution | Year: 2012

The spiny lizard Sceloporus grammicus (Squamata: Phrynosomatidae) is a small reptile from central México and the southern United States, occurring in a wide geographic area characterized by extensive variation in topographic and climatic regimes. Genetic variation among lineages from central México is substantial, though the extent to which this variation corresponds with life-history traits remains obscure. To address part of this puzzle, we studied a population of S. grammicus from Tepeapulco, Hidalgo, México. Male-biased sexual dimorphism was extensive in this population;males were larger than females overall, and expressed proportionately larger heads and longer limbs. Minimum size at sexual maturity was similar in the sexes (males: 43 mm; females: 42 mm). In contrast to other populations from the Central Plateau, reproductive activity of males and females was synchronous. Testicular recrudescence of adult males was initiated in October-November, and maximum testis size maintained from December to July. Female reproductive activity showed no clear seasonal pattern: females had vitellogenic follicles from October to July, and pregnant females were found throughout the year. Female body size was not related to litter size. Neither male nor female gonadal mass was correlated with any abiotic environmental variable examined. Differences in reproductive characteristics among populations of S. grammicus might be indicative of plasticity in response to local environmental conditions, local adaptation, or complex gene × environment interactions. We consider these results in the context of previously studied populations of S. grammicus from the Central Plateau and elsewhere, and propose directions for future research. © 2012 The Authors.

Guzman-Altamirano M.,San Luis Potosi Institute of Scientific Research and Technology | Guzman-Altamirano M.,Instituto Tecnologico Superior Of Irapuato | Gutierrez-Medina B.,San Luis Potosi Institute of Scientific Research and Technology
Optics Express | Year: 2015

We present an efficient alternative to remove lateral chromatic aberration (LCA) in bright field light microscopy images. Our procedure is based on error calibration using time-sequential acquisition at different wavelengths, and error correction through digital image warping. Measurement of the displacements of fiducial marks in the red and green images relative to blue provide calibration factors that are subsequently used in test images to realign color channels digitally. We demonstrate quantitative improvement in the position and boundaries of objects in target slides and in the color content and morphology of specimens in stained biological samples. Our results show a reduction of LCA content below the 0.1% level. © 2015 Optical Society of America.

Ramirez-Bautista A.,Autonomous University of the State of Hidalgo | Smith G.R.,Denison University | Leyte-Manrique A.,Instituto Tecnologico Superior Of Irapuato | Hernandez-Salinas U.,Autonomous University of the State of Hidalgo
Southwestern Naturalist | Year: 2013

Sexual dimorphism in the genus Sceloporus has historically been relatively well studied; however, there is little understanding of how patterns of sexual size dimorphism might vary within species and how that might affect our ability to generalize about the evolution of sexual size-dimorphism in Sceloporus and other organisms. We examined sexual size-dimorphism in a population of Sceloporus spinosus from Guadalcázar, San Luis Potosí, Mexico. Males (n = 85) and females (n = 63) showed no significant sexual dimorphism in size of the body, head, or legs. In combination with the results of other studies on sexual dimorphism in S. spinosus and closely related species of Sceloporus, our results suggest that there can be variation in sexual size-dimorphism within and among species that can limit the ability to make broad generalizations about the phylogenetic patterns of sexual dimorphism in Sceloporus.

Nunez-Colin C.A.,Instituto Nacional de Investigaciones Nucleares | Hernandez-Martinez M.A.,Instituto Nacional de Investigaciones Nucleares | Escobedo-Lopez D.,Instituto Nacional de Investigaciones Nucleares | Ortega-Rodriguez C.,Instituto Tecnologico Superior Of Irapuato
Plant Genetic Resources: Characterisation and Utilisation | Year: 2012

The genus Malacomeles (Decne.) G. N. Jones (Rosaceae subtribe Pyrinae) represents several fruit shrubs, which is mainly distributed in North and Central America, from southern USA to Honduras and Guatemala, although the main distribution of this genus is in Mexico. Five species of the genus Malacomeles have been reported to exist in Mexico. Malacomeles is widely distributed in several mountainous ranges in Mexico, although it is unknown where most of the diversity of the Malacomeles genus is located in the country. The aim of this biogeographic study was to determine the areas of highest diversity of the genus Malacomeles in Mexico based on species richness and diversity indices in order to identify the best regions of Mexico to collect germplasm. The results indicated that most of the diversity of the genus Malacomeles is concentrated in northeast Mexico, mainly in the biogeographic province of Sierra Madre Oriental. In this province, the highest values on three biodiversity indices were found. Thus, this area can be considered as the priority area to collect the germplasm of Malacomeles. M. denticulata is the predominant and the most interesting species in Mexico from the viewpoint of collecting plant genetic resources; this species is mainly distributed in the provinces of Trans-Mexican Volcanic Axis, Mexican Plateau and Sierra Madre del Sur, where secondary priority areas to collect germplasm are located. © Copyright 2012 © NIAB.

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