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Search Results: 1 - 10 of 657212 matches for " J. A. Valdez-Gonzalez "
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Detection of Helicobacter pylori in dental plaque of mexican children by real-time PCR  [PDF]
J. A. Valdez-Gonzalez, P. C. Mares-Moreno, M. J. Kowolik, J. Vargas-Villlarreal, F. Gonzalez-Salazar, M. A. De la Garza-Ramos
Health (Health) , 2014, DOI: 10.4236/health.2014.64034
Abstract:

Dental plaque in adult patients is well identified as a reservoir for Helicobacter pylori. This question still remains unclear in children. The aim of this study is to identify the presence of this bacterium in dental plaque of Mexican pediatric patients, using Real Time Polymerase Chain Reaction (qPCR). Forty patients from 2 to 11 years without dyspeptic symptoms were enrolled. Samples were collected from the subgingival space of the lingual side of the lower molars and cultured in selective medium. Therefore, qPCR analysis was conducted. According to the results obtained in this study, it was found that 35% of the pediatric population who participated tested qPCR positive for the presence of H. pylori in dental plaque samples. No significant associations were detected among isolation rate by gender or age. We found that dental plaque may be a reservoir for H. pylori. However, more research is needed to establish the way of the infection of pediatric population.

South American perspective of the International Charter "Space and Major Disasters"
A. Kotsarenko, V. Grimalsky, R. Pérez Enríquez, V. Yutsis, S. Koshevaya, J. A. López Cruz-Abeyro, C. Valdez-Gonzalez,R. A. Villegas Cerón
Advances in Geosciences (ADGEO) , 2008,
Abstract: Results of the ULF geomagnetic monitoring of the volcano Popocatepetl (Mexico) and their analysis are summarized and presented for the period 2003–2006. Our analysis reveals some anomalies which are considered to be of local volcanic origin: the EM background in the vicinity of the volcano was found to be significantly noisier than at other reference stations; sporadic strong noise-like geomagnetic activity was observed in the H-component; some geomagnetic pulsations were observed only at the Tlamacas station (located at 4 km near the volcano). The results are discussed in terms of a physical mechanism involving the presence of a second magmatic chamber within the volcano and, finally, further perspective directions to study volcanic geodynamical processes besides the traditional ones are given.
Equinococosis canina en un sector del Departamento de Río Cuarto,Provincia de Córdoba, Argentina Canine echinococcosis in an area of Río Cuarto Department(Córdoba, Argentina)
J. GONZALEZ PERALTA,G. GONZALEZ,A. SBAFFO,A. BESSONE
Archivos de medicina veterinaria , 1998,
Abstract: La hidatidosis es una zoonosis parasitaria de distribución universal,producida por un céstode del género Equinococus granulosus,que tiene como huésped definitivo de mayor importancia epidemiológicaal canino. El hombre y los animales de producción son huéspedesintermediarios. En Argentina las zonas que muestran altas tasas de transmisiónde hidatidosis al hombre son: La Patagonia, la Pampa Húmeda y elLitoral. En el resto del país los casos de hidatidosis humana senotifican sólo esporádicamente, como sucede en la provinciade Córdoba, que no posee un programa destinado al estudio epidemiológicoy de control, aunque su zona serrana es considerada endémica porla casuística encontrada. El presente trabajo de investigación se efectuó en ElChacay y Las Albahacas, dos localidades ubicadas en el sector sur de lasSierras de Comechingones, departamento Río Cuarto, provincia deCórdoba, con los siguientes objetivos: a) determinar la proporciónde caninos con Equinococus granulosus, b) valorar el nivelde conocimiento de los habitantes en relación a la enfermedad hidatídica.Se obtuvieron muestras de materia fecal de 120 caninos, por el suministrode Bromhidrato de Arecolina al 1.5%, realizándose el diagnósticopor visualización directa. Se efectuaron encuestas a travésde entrevistas personales a los propietarios de los caninos y a los pobladoresen general. La proporción de equinococosis en caninos fue del 5% en El Chacayy de 17.5% en Las Albahacas. Todos los caninos positivos proveníande establecimientos donde se halló la mayor cantidad de factoresde riesgo. Las 169 entrevistas realizadas determinaron aproximadamenteun 70% de desconocimiento de los pobladores acerca de la enfermedad hidatídica. Los resultados obtenidos justificarían, por su impacto en lasalud pública, la implementación de un programa de estudiosepidemiológicos completos que sirvan de soporte a un futuro programade prevención y control de la hidatidosis a nivel provincial Hydatidosis is a parasitic zoonosis of universal distribution whichis produced by a cestode, the Echinococcus granulosus. This parasiteuses dogs as the epidemiological relevant definitive host, being humansand production animals the intermediate hosts. In Argentina, the regions that present very high rates of hydatidosistransmission to man are: Patagonia, the Pampas and the Littoral. In therest of the country, hydatidosis in humans is reported only sporadically,such as in Córdoba province whose hill area is considered an endemicone, and where there is no program to obtain an epidemiological and controlstudies of this zoonosis. Two localities
Intrinsic chaos and external noise in population dynamics
J. A. Gonzalez,L. Trujillo,A. Escalante
Quantitative Biology , 2002, DOI: 10.1016/S0378-4371(03)00075-X
Abstract: We address the problem of the relative importance of the intrinsic chaos and the external noise in determining the complexity of population dynamics. We use a recently proposed method for studying the complexity of nonlinear random dynamical systems. The new measure of complexity is defined in terms of the average number of bits per time-unit necessary to specify the sequence generated by the system. This measure coincides with the rate of divergence of nearby trajectories under two different realizations of the noise. In particular, we show that the complexity of a nonlinear time-series model constructed from sheep populations comes completely from the environmental variations. However, in other situations, intrinsic chaos can be the crucial factor. This method can be applied to many other systems in biology and physics.
Correlation between Hardness, Structure and Electrochemical Performance of an AlZnMnMg Alloy  [PDF]
S. Valdez, B. Campillo, J. J. Islas
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.49075
Abstract: In this work the structural changes induced by aged treatment have shown a connection with differences of hardness and electrochemical performance. Al-base alloys have been investigated by means of Vickers hardness, X-ray diffraction, scanning electron and short-term electrochemical test. X-ray diffraction result reveals the formation of (MgZn)49Al32 phase for two conditions, the first one is when the magnesium content is upper to 5.49% in as-cast condition and the second one after the thermal treatment carried out at 450?C for 5 h. In addition, the hardness and electrochemical performance has been influenced by the presence and quantity of the (MgZn)49Al32 phase. The addition of magnesium alloying modifies the microstructure, increases the content of (MgZn)49Al32 phase and provides a localized corrosion which conduced to the breakdown of the oxide film (?-Al2O3) formed on the Al alloy surface.
Morfología y protrusión-retracción de la cámara genital femenina de Phyllophaga obsoleta (Coleoptera: Melolonthidae)
ROMERO-LóPEZ, A.A.;ARZUFFI, R.;VALDEZ, J.;MORóN, M. A.;
Acta zoológica mexicana , 2009,
Abstract: the females of phyllophaga obsoleta (blanchard) (coleoptera: melolonthidae) have a great agricultural importance in mexico. they display a "sexual calling" behavior, that expose a bag-like structure on the abdominal tip, wich causes them to attract the males. the content of this structure has been extracted and confirmed his biological activity by wind tunnel and electroantenography bioessays. nevertheless, their morphologic characteristics have not been studied yet. for that reason in the present study, the p. obsoleta abdominal terminalia were characterized morphologically and protrusion-retraction mechanism of bag-like structure was studied. longitudinal dissections of the abdominal terminalia were analyzed with stereoscopic microscopy. the bag-like structure is the protractile genital chamber (pgc) of melolonthidae females and its protrusion and retraction is related to the activity of lateral sterno-sacular muscles with ventral sterno-sacular muscles, as well as for intersegmental membranes viii and ix. they should be involucrated in protrusion and retraction pgc mechanisms.
Morfología y protrusión-retracción de la cámara genital femenina de Phyllophaga obsoleta (Coleoptera: Melolonthidae)
A.A. ROMERO-LóPEZ,R. ARZUFFI,J. VALDEZ,M. A. MORóN
Acta zoológica mexicana , 2009,
Abstract: Las hembras de Phyllophaga obsoleta (Blanchard) (Coleoptera: Melolonthidae), una de las especies de mayor importancia agrícola en México, presentan un "llamado sexual" en el cual exponen una estructura en forma de bolsa del ápice abdominal y provocan la atracción de los machos. El contenido de esta estructura se ha extraído en estudios previos con diferentes disolventes y se ha confirmado su actividad biológica mediante bioensayos con túnel de viento y electroantenografía. Sin embargo, las características morfológicas de esta "bolsa" no han sido estudiadas. Por ello, en el presente trabajo se caracterizó morfológicamente los terminalia del abdomen femenino de P. obsoleta y se estudió el mecanismo de protrusión-retracción de la estructura en forma de bolsa. Se realizaron disecciones longitudinales de los terminalia del abdomen de hembras para su análisis con microscopía estereoscópica. Se encontró que la "bolsa" es la cámara genital protráctil (CGP), propia de las hembras de Melolonthidae y que se encuentra flanqueada por músculos esterno-saculares laterales y esterno-saculares ventrales, así como de membranas intersegmentales VIII y IX. Músculos y membranas podrían estar involucrados en los procesos de protrusión y retracción de la CGP.
Susceptibilidad comparativa de trucha arco iris y salmón coho a ectoparásitos de importancia económica
GONZALEZ,L.; CARVAJAL,J.; MEDINA,A.;
Archivos de medicina veterinaria , 1997, DOI: 10.4067/S0301-732X1997000100015
Abstract: the comparative susceptibility of rainbow trout oncorhynchus mykiss and coho salmon oncorhynchus kisutch to the parasites caligus flexispina (copepoda) and ceratothoa gaudichaudii (isopoda) was studied. the land-based salmon culture was carried out in 8 m3 tanks with independent and continuous sea water supply with two different densities and two replications at bahía metri (41°43'00" lat. s., 72°36'30" long. w). the copepod was found in 3 out of 4 tanks with rainbow trout with a prevalence from l4% to 83%, whereas a prevalence of 25% was found only in one tank with coho salmon. the isopod was present only in 2 of the 4 tanks with reared coho salmon with 28% and 29% of prevalence respectively. this indicates that c. gaudichaudii is an important parasite to the coho salmon and is unimportant to the trout. on the contrary, the coho salmon is more resistant to the copepod parasite. this is the first record of c. flexispina in cultured salmonids from chile.
An alpha-Mellin transform and some of its applications
O. Gonzalez-Gaxiola,J. A. Santiago
International Journal of Contemporary Mathematical Sciences , 2012,
Abstract:
Susceptibilidad comparativa de trucha arco iris y salmón coho a ectoparásitos de importancia económica
L. GONZALEZ,J. CARVAJAL,A. MEDINA
Archivos de medicina veterinaria , 1997,
Abstract: Se evaluó la susceptibilidad comparativa de la trucha Oncorhynchus mykiss y el salmón coho Oncorhynchus kisutch a los ectoparásitos Caligus flexispina (Copepoda) y Ceratothoa gaudichaudii (Isopoda) engordados en estanques. Los salmónidos fueron cultivados en piscinas de 8 m3 con un suministro independiente y continuo de agua de mar a 2 densidades con 2 réplicas, en la localidad de Bahía Metri a 30 km de Puerto Montt. El copépodo se registró en 3 de los 4 estanques de truchas con prevalencias (P) de 14-83%, y en uno de los 4 estanques con salmón coho (P= 25%). El isópodo sólo se encontró en 2 de los estanques de salmón coho (P= 28-29%). Los resultados sugieren que la trucha puede ser un huésped poco susceptible al isópodo pero relevante para el copépodo. El salmón coho, en tanto, podría ser más resistente al copépodo que al isópodo parásito. Este es el primer registro de C. flexispina en cultivos de O. mykiss y O. kisutch en Chile. The comparative susceptibility of rainbow trout Oncorhynchus mykiss and coho salmon Oncorhynchus kisutch to the parasites Caligus flexispina (Copepoda) and Ceratothoa gaudichaudii (Isopoda) was studied. The land-based salmon culture was carried out in 8 m3 tanks with independent and continuous sea water supply with two different densities and two replications at Bahía Metri (41°43'00" Lat. S., 72°36'30" Long. W). The copepod was found in 3 out of 4 tanks with rainbow trout with a prevalence from l4% to 83%, whereas a prevalence of 25% was found only in one tank with coho salmon. The isopod was present only in 2 of the 4 tanks with reared coho salmon with 28% and 29% of prevalence respectively. This indicates that C. gaudichaudii is an important parasite to the coho salmon and is unimportant to the trout. On the contrary, the coho salmon is more resistant to the copepod parasite. This is the first record of C. flexispina in cultured salmonids from Chile.
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