Chetumal, Mexico

University of Quintana Roo
Chetumal, Mexico

The University of Quintana Roo is a Mexican public university with several campuses across the state of Quintana Roo, in the Yucatán peninsula. It was created on 24 May 1991.Its library system holds over 36,634 volumes. Wikipedia.

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Nunez-Jaramillo L.,University of Quintana Roo | Rangel-Hernandez J.A.,National Autonomous University of Mexico | Burgueno-Zuniga B.,National Autonomous University of Mexico | Miranda M.I.,National Autonomous University of Mexico
Frontiers in Behavioral Neuroscience | Year: 2012

Taste memory depends on motivational and post-ingestional consequences; thus, it can be aversive (e.g., conditioned taste aversion, CTA) if a novel, palatable taste is paired with visceral malaise, or it can be appetitive if no intoxication appears after novel taste consumption, and a taste preference is developed. The nucleus accumbens (NAc) plays a role in hedonic reactivity to taste stimuli, and recent findings suggest that reward and aversion are differentially encoded by the activity of NAc neurons. The present study examined whether the requirement for NMDA receptors in the NAc core during rewarding appetitive taste learning differs from that during aversive taste conditioning, as well as during retrieval of appetitive versus aversive taste memory, using the taste preference or CTA model, respectively. Bilateral infusions of NMDA (1 μg/μl, 0.5 μl) into the NAc core were performed before acquisition or before retrieval of taste preference or CTA. Activation of NMDA receptors before taste preference training or CTA acquisition did not alter memory formation. Furthermore, NMDA injections before aversive taste retrieval had no effect on taste memory; however, 24 h later, CTA extinction was significantly delayed. Also, NMDA injections, made before familiar appetitive memory retrieval, interrupted the development of taste preference and produced a preference delay 24 h later. These results suggest that memory formation for a novel taste produces neurochemical changes in the NAc core that have differential requirements for NMDA receptors during retrieval of appetitive or aversive memory. © 2012 Nuñez-jaramillo, Rangel-hernández, Burgueño and Miranda.

Schubert N.,University of Quintana Roo | Schubert N.,Federal University of Santa Catarina | Demes K.,University of British Columbia
Marine Ecology Progress Series | Year: 2017

Light availability is a central determinant of seagrass physiology and therefore distributional patterns. While climax species usually inhabit areas with favorable light conditions, poor competitors like Halophila decipiens Ostenf. are often marginalized into areas of low and high light levels. Thus, their ecological success relies on the ability to withstand and quickly acclimate to contrasting light conditions. Here we determined the acclimation of H. decipiens to different light availabilities and its capacity to rapidly adjust to changing light environments. Morphological and physiological traits differed among depths, with deeper plants having longer, wider leaves and higher photosynthetic performance. This agreed with the reported shade-adapted nature of this species and suggests that the wide tolerance to different light environments of H. decipiens is accompanied by costs resulting in an optimal phenotype for high-light environments, but occasioning a decrease in fitness, most likely related to higher investments in photoprotection and photodamage repair. This species exhibits efficient photoprotective mechanisms, related to energy dissipation, but we also detected chloroplast movement in response to light intensity, which most likely protects the photosynthetic apparatus under high-light stress through minimizing light absorption. H. decipiens also showed high plasticity through quick morphological and physiological adjustments upon transplantation, within days exhibiting characteristics consistent with plants that had originated from the transplant site. This rapidly responding plasticity, in addition to the high sexual reproduction of this species and the formation of extensive seed banks, is likely one of the key features to understanding this species' broad distribution and persistence when outcompeted to the distributional limits of dominant climax species. © Inter-Research 2017.

De Leon-Aldaco S.E.,National Center for Research and Development of Technology | Calleja H.,National Center for Research and Development of Technology | Chan F.,University of Quintana Roo | Jimenez-Grajales H.R.,Electric Research Institute of Mexico
IEEE Transactions on Power Electronics | Year: 2013

This paper presents the reliability analysis of a push-pull converter intended for connection to a 125-W photovoltaic (PV) panel. Four prototypes of the converter were built and tested, using transistors with different ratings. Failure rates were calculated using theMIL HDBK 217 and the IEC TR 62380 procedures. In the latter case, the predictionwas performed taking into account an annual mission profile obtained from the intended installation site, in an area with desert climate temperatures. Failure rate results obtained withMIL HDBK 217 show small differences among the converters, the best performance obtained from the prototype with the lowest on-resistance. Results obtained with IEC TR 62380 indicate that thermal cycles have a significant effect in reliability performance, and should be considered carefully, because PV systems often see large temperature variations.With both procedures, the failure rate contributions from magnetic devices were higher than expected. © 2013 IEEE.

Chan F.,University of Quintana Roo | Calleja H.,CENIDET
IEEE Transactions on Industrial Electronics | Year: 2011

This paper presents the reliability estimation of the power stages in three grid-connected photovoltaic systems. The circuits analyzed are an integrated topology, a two-stage configuration, and a three-stage one, all commutating in the hard-switching mode. The reliability-related parameters, such as the failure rate, are calculated following the procedure outlined in MIL-HDBK 217. A comparison between the topologies is performed, and both the components and the stress factor with the highest contribution to the failure rate are identified. The methods to calculate junction temperature variations are included. © 2006 IEEE.

Gutierrez-Aguirre M.A.,University of Quintana Roo | Cervantes-Martinez A.,University of Quintana Roo
Journal of Natural History | Year: 2013

In Mexico the knowledge of the freshwater copepod fauna is largely incomplete; after a field expedition to survey the Calanoida and Cyclopoida richness in Chiapas (southeastern Mexico), three species increase the full inventory in the country (of around 86 species). In this manuscript the first record of the genus Metacyclops in Mexico and a new record of Acanthocyclops einslei are reported. In addition, a full description of specimens of a new species assignable to the genus Mastigodiaptomus (M. suarezmoralesi sp. nov.) is presented. This research provides a full morphological description of adult males and females of the new species as well as comments on the morphology of Aglaodiaptomus clavipes. The new records were compared with previous taxonomic reports. Detailed analysis and illustration of the copepod morphology have been performed with the aid of camera lucida, light microscopy and scanning electron microscopy. Most of the species recorded show Neotropical affinity. © 2013 Copyright Taylor and Francis Group, LLC.

Available type material of Prionospio heterobranchia Moore, 1907, P. (Prionospio) texana Hartman, 1951, P. spongicola Wesenberg-Lund, 1958 and P. (P.) newportensis Reish, 1959, as well as newly collected material from the Southern Gulf of Mexico and Chetumal Bay in the Caribbean Sea, was examined. Several important differences were found between P. heterobranchia, P. (Prionospio) texana, P. spongicola and P. (P.) newportensis, and as a result, these three species are removed from synonymy with P. heterobranchia Moore, 1907, and redescribed and reinstated as valid species. In addition, three new species were identified and described: P. caribensis sp. nov., P. rosariae sp. nov. and P. jamaicensis sp. nov. A key to all species of Prionospio with five pairs of branchiae is provided. © 2013 Springer-Verlag Berlin Heidelberg and AWI.

Delgado-Blas V.H.,University of Quintana Roo | Salazar-Silva P.,Colegio de Mexico
Zootaxa | Year: 2011

The aim of this study was to provide a revised taxonomic catalogue of Spionidae species recorded from the Grand Caribbean. The names included were compiled from the checklists of Salazar-Vallejo (1996) and Perkins and Savage (1975). Names were revised and updated based on recent revisions. For each species, the original name is included together with current and previous names under which it has been recorded; all with associated citations. The type locality of each species, museum or institution where the type materials are deposited, and comments on systematics and geographic distributions are also included. The catalogue lists 66 species in 24 genera and at the end a list of species with questionable distribution in the Grand Caribbean is included. © 2011 . Magnolia Press.

Aguilar J.O.,Research Center Cientifica Of Yucatan | Aguilar J.O.,University of Quintana Roo | Bautista-Quijano J.R.,Research Center Cientifica Of Yucatan | Aviles F.,Research Center Cientifica Of Yucatan
Express Polymer Letters | Year: 2010

Electrical conductivity of 150-200 μm thick polysulfone films loaded with 0.05-0.75% w/w multiwall carbon nanotubes was systematically investigated for two types of dispersion states, uniformly dispersed and agglomerated at the micro-scale. The percolation threshold was found at 0.11% and 0.068% w/w for the uniformly dispersed and agglomerated films, respectively. Overall, the conductivity of the films with agglomerated nanotubes was higher than that of the uniformly dispersed ones, with marked differences of 2 to 4 orders of magnitude for carbon nanotubes loadings in the upper vicinity of the percolation threshold (0.1-0.3% w/w). The increased conductivity of the agglomerated state is explained by the increased nanotube-to-nanotube contact after the percolating network has formed, which facilitates electron transfer. © BME-PT.

Atoche A.C.,Autonomous University of Yucatán | Castillo J.V.,University of Quintana Roo
Sensors | Year: 2012

A high-speed dual super-systolic core for reconstructive signal processing (SP) operations consists of a double parallel systolic array (SA) machine in which each processing element of the array is also conceptualized as another SA in a bit-level fashion. In this study, we addressed the design of a high-speed dual super-systolic array (SSA) core for the enhancement/reconstruction of remote sensing (RS) imaging of radar/synthetic aperture radar (SAR) sensor systems. The selected reconstructive SP algorithms are efficiently transformed in their parallel representation and then, they are mapped into an efficient high performance embedded computing (HPEC) architecture in reconfigurable Xilinx field programmable gate array (FPGA) platforms. As an implementation test case, the proposed approach was aggregated in a HW/SW co-design scheme in order to solve the nonlinear ill-posed inverse problem of nonparametric estimation of the power spatial spectrum pattern (SSP) from a remotely sensed scene. We show how such dual SSA core, drastically reduces the computational load of complex RS regularization techniques achieving the required real-time operational mode. © 2012 by the authors.

Six species of Prionospio are described from the Southern Gulf of Mexico and the Caribbean Sea. Five of these species, P austella sp. nov., P. crassumbranchiata sp. nov., P. jonatani sp. nov., P oligopinnulata sp. nov., and P. rotunda sp. nov. are new to science whereas Prionospio cristata Foster, 1971 has been previously described from the Grand Caribbean region. P. austella sp. nov. has a prostomium with a small medial peak on the anterior margin, low dorsal folds on chaetigers 6-11, rounded and subtriangular neuropodial lamellae on chaetigers 1 and 3, respectively, and all hooks lack a secondary hood. P. crassumbranchiata sp. nov. has a laterally separate peristomium partially fused dorsally with chaetiger 1, digiti-form pinnules on the lateral and posterior faces of the first pair of branchiae and rectangular neuropodial lamellae on chaetigers 2-5. Prionospio jonatani sp. nov. has a narrow prostomium, subtriangular notopodial lamellae on chaetigers 6-21, notopodial prechaetal lamellae slightly basally fused with the notopodial postchaetal lamellae and square neuropodial lamellae on chaetiger 3. P. oligopinnulata sp. nov. has a square-shaped prostomium, high dorsal crests on chaetigers 7-8, low dorsal folds on chaetigers 9-14, subtriangular neuropodial lamellae on chaetigers 2-3, and branchial pairs 2 and 3 are triangular. P rotunda sp. nov. has an anteriorly rounded prostomium, trapezoid neuropodial lamellae on chaetiger 3, high dorsal crests on chaetiger 7, and branchial pairs 2 and 3 are cirriform. A key is provided for all the species known from the Grand Caribbean region in the "steentrupi-group" with four branchial pairs. Copyright © 2015 Magnolia Press.

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