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Search Results: 1 - 10 of 1058 matches for " Trejo-Valdivia "
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Encuesta Nacional de Cobertura de Vacunación (influenza, neumococo y tétanos) en adultos mayores de 60 a?os en México
Trejo-Valdivia,Belem; Mendoza-Alvarado,Laura R; Palma-Coca,Oswaldo; Hernández-ávila,Mauricio; Téllez-Rojo Solís,Martha María;
Salud Pública de México , 2012, DOI: 10.1590/S0036-36342012000100006
Abstract: objective: determine vaccination coverage (vc) among adults 60 years of age and older (ep), for influenza, pneumococcal and tetanus vaccines, association with socio-demographic characteristics and heterogeneity at state level. material and methods: cross-sectional analysis based on information from 18 015 households visited in a national survey. general and vaccine information (self-report) for a randomly selected elder in each household is available. results: the national vc level was found to be 56.5% (±0.97) for influenza, 44.3% (±0.98) for pneumococcus and 61.8% (±0.96) for tetanus. the vc was significantly lower for ep without health social services and higher for women. almost 20.0% of ep recognized not having vaccines at all, due mainly that they didn't know it was a duty. conclusions: important improvements are shown in vaccination coverage among elderly in mexico. differentials suggest the need to intensify information campaigns and actions that could improve the accessibility to vaccines for this population.
Association between the plasma/whole blood lead ratio and history of spontaneous abortion: a nested cross-sectional study
Héctor Lamadrid-Figueroa, Martha M Téllez-Rojo, Mauricio Hernández-Avila, Belem Trejo-Valdivia, Maritsa Solano-González, Adriana Mercado-Garcia, Donald Smith, Howard Hu, Robert O Wright
BMC Pregnancy and Childbirth , 2007, DOI: 10.1186/1471-2393-7-22
Abstract: We studied 207 pregnant Mexico City residents during the 1st trimester of pregnancy, originally recruited for two cohorts between 1997 and 2004. Criteria for inclusion in this study were having had at least one previous pregnancy, and having valid plasma and blood Pb measurements. Pb was measured in whole blood and plasma by inductively coupled plasma mass spectrometry using ultra-clean techniques. History of miscarriage in previous pregnancies was obtained by interview. The incidence rate of spontaneous abortion was defined as the proportion of previous pregnancies that resulted in miscarriage. Data were analyzed by means of Poisson regression models featuring the incidence rate of spontaneous abortion as the outcome and continuous or categorized plasma/blood Pb ratios as predictor variables. All models were adjusted for age and schooling. Additionally, logistic regression models featuring inclusion in the study sample as the outcome were fitted to assess potential selection bias.The mean number of miscarriages was 0.42 (range 0 to 4); mean Pb concentrations were 62.4 and 0.14 μg/L in whole blood and plasma respectively. Mean plasma/blood Pb ratio was 0.22%. We estimated that a 0.1% increment in the plasma/blood Pb ratio lead was associated to a 12% greater incidence of spontaneous abortion (p = 0.02). Women in the upper tertile of the plasma/blood Pb ratio had twice the incidence rate of those in the lower tertile (p = 0.02). Conditional on recruitment cohort, inclusion in the study sample was unrelated to observable characteristics such as number of abortions, number of pregnancies, blood Pb levels, age schooling, weight and height.Women with a large plasma/whole blood Pb ratio may be at higher risk of miscarriage, which could be due to a greater availability of placental barrier-crossing Pb.Several studies have reported a positive association between maternal blood lead concentration and the risk of spontaneous abortion [1-3]. This is of concern since one of the
Aplicación del análisis estadístico de datos censurados para el manejo de respuestas incompletas en la escala CES-D
Ietza Rocío Bojorquez-Chapela,Belem Trejo Valdivia,V. Nelly Salgado de Snyder
Salud mental , 2012,
Abstract: Objetivo Ejemplificar el uso del análisis de datos censurados en el manejo de datos incompletos de la CES-D utilizando una base de datos de un estudio con mujeres rurales de México. Material y Método Los datos analizados se recogieron en un estudio transversal con 416 mujeres de la Mixteca Baja, al sur de México. Con un enfoque de Análisis de Supervivencia (AS), se presenta una descripción general del comportamiento de las puntuaciones de la CES-D junto con la estimación de patrones de asociación entre esos puntajes y variables independientes a partir del modelo de riesgos proporcionales de Cox, y se hace una comparación entre estos resultados y los obtenidos de un modelo de regresión lineal. Resultados Utilizando sólo la información de las observaciones con datos completos, la puntuación promedio de la CES-D fue de 11.0 y la prevalencia de síntomas por arriba del punto de corte (16) fue de 23.2%. El 25.2% de las mujeres no contestó al menos un reactivo. Al hacer el AS, el promedio estimado de la puntuación fue de 14.8. La supervivencia por encima del punto de corte corresponde a una prevalencia estimada del 21%. Conclusiones El AS es útil en el manejo de bases que presentan datos faltantes por ejemplo en escalas como CES-D. En nuestro ejemplo, el elevado porcentaje de observaciones con respuestas faltantes ocasionó una pérdida de precisión en los estimadores. Las diferencias de puntuaciones promedio por reactivo entre observaciones con datos perdidos y completos sugieren un patrón de no-respuesta que no es aleatorio, y que de no tomarse en cuenta podría sesgar la estimación, tanto del promedio de la escala como de su asociación con otras variables. El AS utilizó la información de casi la totalidad de las participantes en el estudio incluyendo aquellas que no respondieron todos los reactivos de la escala.
El potencial de agua del sustrato en la germinación de maíces con tolerancia y sensibilidad a la sequía
Tsougkrianis, Nikolaos;Pe?a-Valdivia, Cecilia Beatriz;Trejo López, Carlos;Molina Galán, José Domingo;
Agricultura técnica en México , 2009,
Abstract: the objective of this study was to characterize seed germination of drought sensitive and tolerant maize in laboratory conditions. cafime o, qpm (quality protein maize) h519, tuxpe?o sequia c0 and zacatecas 58 o, drought sensitive, and cafime sm16 sequia, tuxpe?o sequia c8 and zacatecas 58 sm19 sequia, drought tolerant cultivars, were evaluated. the seeds were germinated in vermiculite with ψw of-0.03 mpa (well watered), -1.28, -1.41, -1.58 y -2.05 mpa (with 6% of humidity), were weighted every 12 h and the percentage of water absorbed and germination was calculated. the maximum imbibition (up to germination) in the ψw of -0.03 mpa of all cultivars was significantly major compared with the other ψw evaluated and it reached between 40% and 70%, in variable times between the cultivars, from 48 h (cv. caf. seq.) untill 170 h (cv tux. seq. c8). the cafime sm16 and zac. 58 sm19 cultivars reached maximum germination four times higher with the ψw of -2.05 mpa compared with their respective drought sensitive cultivars. the drought tolerance of some drought tolerant cultivars, like cafime sm16, is expressed since the germination stage; even though this respond contrasts between cultivars. some drought tolerant cultivars react negatively at the high substrate ψw and reach germination percentages significantly higher when the substrate ψw is significantly lower, between -1.28 and -1.58 mpa.
Técnica de riego para incrementar la eficiencia del uso de agua en jitomate Irrigation technique to increase the eficiency of water use in tomato
Anselmo López Ordaz,Carlos Trejo López,Carlos Ramírez Ayala,Cecilia Beatriz Pe?a Valdivia
Revista mexicana de ciencias agrícolas , 2011,
Abstract: El objetivo de esta investigación fue estudiar en condiciones de hidroponía e invernadero, el efecto de dos niveles de humedad aprovechable del sustrato en plantas de jitomate (Solanum lycopersicum L), mediante la técnica de riego secado parcial de la raíz (SPR). Para ello se evaluaron variables fisiológicas (materia seca de hoja, tallo, raíz y fruto, relaciones hídricas, intercambio de gases, rendimiento), calidad de fruto (firmeza, sólidos solubles totales, pH y conductividad eléctrica), y la eficiencia del uso de agua. El experimento se estableció en Lomas de San Esteban, Texcoco, Estado de México, en 2006. Las plantas crecieron en contenedores de volumen homogéneo, con tezontle, la raíz se dividió en dos partes, y se aplicaron dos tratamientos de humedad aprovechable (HA) residual en el sustrato, testigo: 80%≤HA≤ 100% y 80%≤HA≤ 100% y SPR: 80%≤HA≤ 100% y 30%≤HA≤ 100%. Estos tratamientos se iniciaron 28 días después del transplante y se mantuvieron hasta el final del experimento. Los resultados obtenidos indicaron que el tratamiento SPR mostró diferencias estadísticas significativas (p≤ 0.05), respecto al testigo, en relación con la tasa de fijación de CO2 (SPR, 17.67 y testigo 9.23 μmol m2 s1) a 86 días de haber iniciado los tratamientos (DDIT), volumen evapotranspirado por planta durante todo el experimento (SPR 186.7 L y testigo 229 L), la calidad de fruto incrementó: firmeza 25%, los sólidos solubles totales 13% y la conductividad eléctrica 13%, respecto al testigo; y la eficiencia en el uso del agua (EUA) con base en la materia seca incrementó 29% y EUA instantánea fue de 57, 61 y casi 100%, respecto al testigo, a los 65, 80 y 86 DDIT respectivamente, sin afectar el rendimiento (SPR 363.2 g y testigo 345.8 g) y el potencial total del agua (SPR -0.54 y testigo -0.57; SPR -0.46 y testigo -0.55 MPa), a los 79 y 118 DDIT respectivamente. The aim of this research was to study in hydroponics and greenhouse conditions the effect of two levels of usable moisture from the substrate in tomato plants (Solanum lycopersicum L.), by the irrigation technique of partial root drying (PRD). For that, physiological variables were evaluated (dry matter of leaf, stem, root and fruit, water relations, gas exchange, yield), fruit quality (firmness, total soluble solids, pH and electrical conductivity) and the efficiency of water use. The experiment was done in Lomas de San Esteban, Texcoco, Mexico State in 2006. Plants grew in homogeneous volume containers with tezontle, the root was divided in two parts and two available moisture (AM) treatments were applied residual
Efectos del potencial de agua en el crecimiento radical de plántulas de Agave salmiana Otto Ex Salm-Dyck
Sánchez-Urdaneta,Adriana B; Pe?a-Valdivia,Cecilia B.; Aguirre R,J. Rogelio; Trejo,Carlos; Cárdenas,Elizabeth;
Interciencia , 2004,
Abstract: the aim of this study was to characterise the effects of substrate water potential (yw) of the physiological and biophysical characteristics of root seedlings of agave salmiana otto ex salm-dyck under laboratory conditions. seedlings of 3-4cm root length were maintained in vermiculite at yw of -0.03, -0.65, -1.48 and -2.35mpa for 24h. at the end of this period a group of seedlings was re-hydrated and from another group roots were harvested and the elongation, dry and fresh weight, and proline content were quantified. electrical conductivity, ph and the concentrations of cu, fe, k, mn, na and zn were determined in the root re-suspension media. the effect of re-hydration on root growth after 24h was evaluated. the low yw of the substrate did not affect significantly root length, but fresh weight diminished (23.5 to 49.2%), and the damage index increased 36.0%. the ions leached to the re-suspension media were not significantly affected and the proline root content increased from 1.6 to 2.1μmol·mg-1 of dry matter. roots continued growing after re-hydration.
Permeabilidad de las membranas radicales de plántulas de frijol (phaseolus vulgaris l.) silvestre y domesticado bajo déficit de humedad
Sánchez-Urdaneta,Adriana B; Pe?a-Valdivia,Cecilia B; Trejo,Carlos; Aguirre R,J. Rogelio; Cárdenas,Elizabeth; Galicia Jiménez,Ana B;
Interciencia , 2003,
Abstract: wild and domesticated common bean root membrane permeability was evaluated in its response to water deficit. wild common bean from chihuahua (sch) and durango (sd) and the cv. bayomex were used; 72h old seedlings of 3-4cm root length were maintained for 24h in vermiculite with water potentials (ψw) of -0.03, -0.65, -1.48 and -2.35mpa. roots collected were maintained in deionized water for 3h and then relative water content (cra), and k+ and na+ concentrations in the media were quantified; electrical conductivity and ph of the medium were measured every 30min. cra sharply decreased (46%) in the cultivar and sd with water deficit, but diminished slightly in sch (15%). electrolyte leakage showed two phases in all treatments, in the initial 30min it went from 0.8 to 3.2s·cm-1·g-1 of dry tissue in the cultivar, from 1.4 to 3.1 in sch and from 2.2 to 6.4 in sd; but, after the next 2.5h the increments were not significant. the significant interaction showed that although sch was not damaged (0.84%) with any ψw tested, sd and the cultivar were drastically damaged (>50%) with -2.35mpa. in contrast with electrical conductivity, media ph continued increasing during the first 3h. the lower ψw promoted a significant ph increase for the domesticated common bean root (from 4.59 to 4.91) and sd (from 4.86 to 5.16). high yw produced significantly similar (p£0.75) k+ leakage (5.9mg·g-1 in average) in all three variants, but the water deficit caused increase of k+ leakage (up to 2.5 times), while na+ leakage was not detected. based on cra, electrical conductivity, damage index and stress recovery data, it seems that low ψw affected root membranes of sch less than those of sd and the domesticated common bean..
Técnica de riego para incrementar la eficiencia del uso de agua en jitomate
López Ordaz, Anselmo;Trejo López, Carlos;Ramírez Ayala, Carlos;Pe?a Valdivia, Cecilia Beatriz;Tijerina Chávez, Leonardo;Carrillo Salazar, José Alfredo;
Revista mexicana de ciencias agrícolas , 2011,
Abstract: the aim of this research was to study in hydroponics and greenhouse conditions the effect of two levels of usable moisture from the substrate in tomato plants (solanum lycopersicum l.), by the irrigation technique of partial root drying (prd). for that, physiological variables were evaluated (dry matter of leaf, stem, root and fruit, water relations, gas exchange, yield), fruit quality (firmness, total soluble solids, ph and electrical conductivity) and the efficiency of water use. the experiment was done in lomas de san esteban, texcoco, mexico state in 2006. plants grew in homogeneous volume containers with tezontle, the root was divided in two parts and two available moisture (am) treatments were applied residual in substrate, control: 80%≤am≤ 100% and 80%≤am≤ 100% and prd: 80%≤ am≤ 100% and 30%≤ am≤ 100%. the treatments started 28 days after transplantation and continued until the end of the experiment. results indicated that prd treatment, showed statistically significant differences (p≤ 0.05) than the control, in relation to co2 fixation rate (prd, 17.67 and control 9.23 μmol m2 s1) at 86 days of initiating the treatment (dait), evapotranspirated volume per plant throughout the experiment (prd 186.7 l and control 229 l), fruit quality increased: firmness 25%, total soluble solids 13% and electrical conductivity 13%, compared with control; efficiency in water use (ewu) based on dry matter increased by 29% and instantly ewu was 57, 61 and almost 100% respect to the control at 65, 80 and 86 dait respectively, without affecting yield (prd 363.2 g and control 345.8 g) and total water potential (prd -0.54 and control -0.57; prd -0.46 and control -0.55 mpa), at 79 and 118 dait respectively.
CONSUMO DE RESERVAS DE LA SEMILLA DE FRIJOL PARA LA EMERGENCIA Y DESARROLLO INICIAL EN DIFERENTES PROFUNDIDADES DE SIEMBRA
Raquel Celis-Velázquez,Cecilia Beatriz Pe?a-Valdivia,Carlos Trejo-López,Juan Rogelio Aguirre-Rivera
Agronomía Mesoamericana , 2008,
Abstract:
Identificación de especies y áreas prioritarias para el estudio de la reproducción de aves rapaces de Argentina
Trejo,Ana;
El hornero , 2007,
Abstract: ninety seven publications on raptor breeding biology in argentina (until 2006) were analyzed and classified according to species, year of publication, province, habitat associations, and subject. the amount of publications has increased, especially since 1970. almost all provinces are represented. there is no quantitative information for 33 species, 19 diurnal and 14 nocturnal. to determine priority areas for the study of reproduction, species richness, number of endemic or exclusive species, conservation status and degree of information on the species were considered for each life zone. on this basis, selva paranaense, yungas, chaco, and the andean-patagonian forests were established as the most important areas. analyzing the preferred habitat of the 33 species with no information, 85% are typical forest species. an evident disparity exists between the achieved knowledge and the necessity of conserving a vulnerable fauna (for its low habitat utilization flexibility and higher conservation risk). this is due to two fundamental factors: scarcity of researchers, and structural complexity of the habitat.
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