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Search Results: 1 - 10 of 465883 matches for " Rogelio A. Alonso "
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Effective Population Size, Genetic Variation, and Their Relevance for Conservation: The Bighorn Sheep in Tiburon Island and Comparisons with Managed Artiodactyls
Jaime Gasca-Pineda, Ivonne Cassaigne, Rogelio A. Alonso, Luis E. Eguiarte
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078120
Abstract: The amount of genetic diversity in a finite biological population mostly depends on the interactions among evolutionary forces and the effective population size (Ne) as well as the time since population establishment. Because the Ne estimation helps to explore population demographic history, and allows one to predict the behavior of genetic diversity through time, Ne is a key parameter for the genetic management of small and isolated populations. Here, we explored an Ne-based approach using a bighorn sheep population on Tiburon Island, Mexico (TI) as a model. We estimated the current (Ncrnt) and ancestral stable (Nstbl) inbreeding effective population sizes as well as summary statistics to assess genetic diversity and the demographic scenarios that could explain such diversity. Then, we evaluated the feasibility of using TI as a source population for reintroduction programs. We also included data from other bighorn sheep and artiodactyl populations in the analysis to compare their inbreeding effective size estimates. The TI population showed high levels of genetic diversity with respect to other managed populations. However, our analysis suggested that TI has been under a genetic bottleneck, indicating that using individuals from this population as the only source for reintroduction could lead to a severe genetic diversity reduction. Analyses of the published data did not show a strict correlation between HE and Ncrnt estimates. Moreover, we detected that ancient anthropogenic and climatic pressures affected all studied populations. We conclude that the estimation of Ncrnt and Nstbl are informative genetic diversity estimators and should be used in addition to summary statistics for conservation and population management planning.
Detección de Salmonella spp y Listeria monocytogenes en quesos frescos y semimadurados que se expenden en vía pública en la ciudad de México
Claudia D. Alcázar Monta?ez,María Salud Rubio Lozano,Fernando Nú?ez Espinosa,Rogelio A. Alonso Morales
Veterinaria México , 2006,
Abstract: Con el objetivo de determinar la inocuidad bacteriológica de los quesos frescos y semimadurados que se venden en algunos mercados sobre ruedas en la ciudad de México, se realizó la detección simultánea de Salmonella spp y de Listeria monocytogenes, mediante la técnica de reacción en cadena de la polimerasa (PCR), así como con los métodos bacteriológicos convencionales, según la normatividad correspondiente para cada microorganismo; es decir, la NOM-114-SSA1-1994 mexicana, que constituye un método para la determinación de Salmonella en alimentos; de igual manera la NOM-143-SSA1-1995 mexicana, que representa un método de prueba microbiológica para alimentos y determinación de L. monocytogenes. Se analizaron 120 muestras seleccionadas al azar, provenientes de cuatro mercados sobre ruedas de una zona del sur de la ciudad de México. La metodología propuesta para la PCR múltiple se basó en la amplifi cación simultánea de los genes InvA e Iap procedentes de los genomas de Salmonella spp y de L. monocytogenes, respectivamente; de igual forma, la metodología para la extracción de ADN bacteriano a partir de las muestras se desarrolló con el fi n de eliminar o disminuir la posible interferencia de inhibidores propios del alimento mediante centrifugación previa de las muestras y se comprobó que la amplifi cación de ambos resultó positiva, aun cuando los patógenos se encuentren presentes en las muestras a una concentración de por lo menos 30 UFC/g. Del total de muestras analizadas con la técnica de PCR, sólo tres resultaron positivas a la presencia de Salmonella spp, en ninguna estuvo presente L. monocytogenes, en contraste con los resultados de los métodos bacteriológicos, por medio de los cuales no se obtuvo ningún resultado positivo.
Polymorphism of locus DRB3.2 in populations of Creole Cattle from Northern Mexico
Fernández, Ilda G.;Ramírez, José Gonzalo Ríos;Vázquez, Amanda Gayosso;Arvizu, Raúl Ulloa;Morales, Rogelio A. Alonso;
Genetics and Molecular Biology , 2008, DOI: 10.1590/S1415-47572008005000020
Abstract: keywords : bola-drb3.2; polymorphism; creole cattle; pcr-rflp.
Lipofection improves gene targeting efficiency in E14 TG2a mouse embryonic stem cells
Sandra M. López-Heydeck,Marcos Cajero-Juárez,Rogelio A. Alonso-Morales,José S. Martínez-Casta?eda
Veterinaria México , 2009,
Abstract: Durante los últimos 15 a os se ha demostrado que la electroporación representa el método ideal para la transfección de células troncoembrionarias de ratón; sin embargo, demanda grandes cantidades de ADN y células, así como equipo caro y delicado, ello hace que este proceso sea costoso y laborioso. La lipofección es un método de transfección que requiere menos de células y ADN que la electroporación; asimismo, ha probado ser efi ciente en gran número de líneas celulares. Se ha demostrado que después de lipofectar células troncoembrionarias de ratón, éstas mantienen su pluripotencia y son capaces de formar quimeras de línea germinal y se transfectan con mayor efi ciencia que con electroporación, pero no se ha notifi cado la mutagénesis dirigida mediante la lipofección de células troncoembrionarias de ratón. El objetivo del presente trabajo fue saber si la lipofección puede ser utilizada con la misma o mayor efi ciencia que la electroporación para los protocolos regulares de mutagénesis dirigida; en este contexto, se compara la efi ciencia en mutagénesis dirigida entre estas técnicas en células troncoembrionarias de ratón E14TG2a, utilizando un vector de reemplazo. Entre las células transfectadas no se hallan diferencias en la efi ciencia en mutagénesis dirigida entre grupos; sin embargo, los resultados que aquí se ofrecen muestran que la lipofección es tres veces más efi ciente en la transfección, lo cual indica que la lipofección es un método alternativo menos costoso para obtener mutagénesis dirigida en células troncoembrionarias de ratón.
La lipofección incrementa la eficiencia de mutagénesis dirigida en células troncoembrionarias de ratón E14 TG2a
López-Heydeck, Sandra M.;Cajero-Juárez, Marcos;Alonso-Morales, Rogelio A.;Martínez-Casta?eda, José S.;Robles-González, José F.;Barbabosa-Pliego, Alberto;Vázquez-Chagoyán, Juan C.;
Veterinaria México , 2009,
Abstract: electroporation has been the method of election for transfection of murine embryonic stem cells for over 15 years; however, it is a time consuming protocol because it requires large amounts of dna and cells, as well as expensive and delicate equipment. lipofection is a transfection method that requires lower amounts of cells and dna than electroporation, and has proven to be efficient in a large number of cell lines. it has been shown that after lipofection, mouse embryonic stem cells remain pluripotent, capable of forming germ line chimeras and can be transfected with greater efficiency than with electroporation; however, gene targeting of mouse embryonic stem cells by lipofection has not been reported. the objective of this work was to find out if lipofection can be used as efficiently as electroporation for regular gene targeting protocols. this context compares gene targeting efficiency between these techniques in mouse embryonic stem cells e14tg2a, using a gene replacement type vector. no differences were found in gene targeting efficiency between groups; however, lipofection was three times more efficient than electroporation in transfection efficiency, which makes lipofection a less expensive alternative method to produce gene targeting in mouse embryonic stem cells.
Respuesta inflamatoria sistémica inespecífica infecciosa y no infecciosa en los pacientes críticos
Padrón Sánchez,Armando; Ayala Pérez,Jorge Luis; Puga Torres,Mario Santiago; Alonso Díaz,Tammy; Salazar González,Tania; Qui?ones Zamora,Andrés; Pérez Reyes,Rogelio; Pico Pe?a,Jorge Luis;
Revista Cubana de Medicina Militar , 2004,
Abstract: the localized inflamation is a protection response closely controlled by the organism in the place of the lesion. the loss of this local control or the appearance of a hyperactive response conditions a systemic response that is known as systemic inflammatory reponse syndrome (sirs). the sample was composed of 90 patients that were divided into 2 groups: group a, patients with criteria of sirs of non infectious cause, and group b, patients with criteria of sirs of infectious cause. the severity level within the first 48 hours was determined by the apache ii system. the score for the multiple organ dysfunction syndrome (mods) was also used. the chi square test was used for the association of the categoric variables, whereas the comparison of means was made by the t student test or the unidirectional variance analysis. the sirs of infectious cause showed the highest mortality and the poorest prognosis (p< 0.05).
A Comparative Study of the Economic Feasibility of Employing CHP Systems in Different Industrial Manufacturing Applications  [PDF]
Chad A. Wheeley, Pedro J. Mago, Rogelio Luck
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.35079
Abstract: Extensive research work including multiple methodologies and numerous simulations have been completed in order to determine the economic effectiveness of employing CHP at commercial and residential sites. In contrast to the above, very few attempts have been made to develop methodologies to study the feasibility of CHP systems at industrial manufacturing facilities. As a result, practical opportunities for CHP at industrial sites are often not realized or even investigated. It follows that there is a need in the CHP related literature for an analysis that is explicit and yet general enough to determine the economic viability and potential for success of CHP systems at industrial manufacturing facilities. Therefore, the purpose of this paper is to clearly outline a methodology to determine the economic effectiveness of installation and operation of a CHP system at industrial facilities that have a need for space or process heating in the form of steam. The effect on the CHP system economic performance of several parameters, such as the project payback, internal rate of return, net present value, etc., are considered in the proposed methodology. The applicability and generality of the methodology is illustrated by examples including four different manufacturing facilities. The effects of the variability of factors such as annual facility operational hours during which both process heat and electricity are needed, facility average hourly thermal load, cost of utility supplied electricity, and CHP fuel type and associated fuel cost, on the outcome of the economic analysis are also examined.
Caracterización molecular de aislamientos mexicanos del virus de la anemia infecciosa del pollo, a través del polimorfismo...
Néstor Ledesma Martínez,Tamas Fehervari,Rogelio Alonso
Veterinaria México , 2007,
Abstract: La anemia infecciosa del pollo es una de las enfermedades inmunodepresoras más frecuentes de las aves domésticas. El agente causal es un Gyrovirus. Se identifi caron 30 muestras de virus de anemia infecciosa mediante la amplifi cación por PCR de un fragmento de 675 bp, correspondiente al extremo aminoterminal del gen de la proteína VPI. Los fragmentos amplifi cados fueron caracterizados mediante el polimorfi smo en la longitud de los fragmentos de restricción, utilizando las endonucleasas HaeIII, HinfI y HpaII. De las 30 muestras, 12 se clasifi caron en cuatro grupos virales previamente descritos, mientras que las 18 restantes formaron seis grupos más, algunos de ellos nuevos. Estos resultados indican que la variabilidad genética de los virus de anemia infecciosa es amplia e incluye tipos virales similares a otras regiones del mundo y variantes locales nuevas.
Role of Dehydrodiferulates in Maize Resistance to Pests and Diseases
Rogelio Santiago,Rosa A. Malvar
International Journal of Molecular Sciences , 2010, DOI: 10.3390/ijms11020691
Abstract: Phenolic esters have attracted considerable interest due to the potential they offer for peroxidase catalysed cross-linking of cell wall polysaccharides. Particularly, feruloyl residues undergo radical coupling reactions that result in cross-linking (intra-/intermolecular) between polysaccharides, between polysaccharides and lignin and, between polysaccharides and proteins. This review addresses for the first time different studies in which it is established that cross-linking by dehydrodiferulates contributes to maize’s defences to pests and diseases. Dehydrodiferulate cross-links are involved in maize defence mechanisms against insects such as the European, Mediterranean, and tropical corn borers and, storage pest as the maize weevil. In addition, cross-links are also discussed to be involved in genetic resistance of maize to fungus diseases as Gibberella ear and stalk rot. Resistance against insects and fungus attending dehydrodiferulates could go hand in hand. Quantitative trait loci mapping for these cell wall components could be a useful tool for enhancing resistance to pest and diseases in future breeding programs.
Effects of the Contiguity Between the Extinction and the Reinforcement Components in Observing-response Procedures
Escobar, Rogelio;Bruner, Carlos A.;
Revista mexicana de análisis de la conducta , 2008,
Abstract: the role of the stimulus correlated with extinction (s-) in observing-response procedures has been ambiguous. although the s- is associated with extinction, some studies demonstrated that it effectively sustained observing behavior. to explore the conditions responsible for the s- to function as a conditioned reinforcer, the present experiment showed whether observing responses during an extinction component are controlled by the temporal contiguity between s- presentation and the reinforcement component. presses on one lever were reinforced on a mixed schedule of reinforcement random-interval extinction. pressing a second lever resulted in 5-s stimuli correlated with the components of the mixed schedule. for one group of three rats after observing responses were established, a no-consequence interval (nci) was added between the end of the extinction component and the beginning of the reinforcement component. for other three rats the nci was added between the end of the reinforcement component and the beginning of the extinction component. observing responses during the extinction component decreased only when the nci was added at the end of the extinction component. it was concluded that although the s- is nominally correlated with extinction it may function as a conditioned reinforcer because it is intermittently paired with the reinforcement component.
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