oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 359 )

2018 ( 555 )

2017 ( 533 )

2016 ( 723 )

Custom range...

Search Results: 1 - 10 of 362477 matches for " Javier E. Ortiz Cárdenas "
All listed articles are free for downloading (OA Articles)
Page 1 /362477
Display every page Item
Gestión universitaria, racionalidad y trayectorias escolares
Javier E. Ortiz Cárdenas
Reencuentro , 2003,
Abstract: En este artículo se presentan diversas formas de entender las trayectorias escolares en relación con el juego de fuerzas que se establece en el campo universitario, para lo cual es pertinente discutir la relación entre dispositivo de gestión, racionalidad y trayectorias. El estudio reconstruye, de forma sintética, la concepción de trayectorias como núcleo de ideas y acciones, en tanto saberes y prácticas escolares que forman una trama que va desde la manera en que la Universidad define finalidades, objetivos, programas y los operacionaliza a través de estrategias de gestión académicoadministrativas, hasta la manera en que los estudiantes actúan en relación con tales determinaciones e incitaciones, i.e., a través de juegos y estrategias de poder.
Acercamiento a la actualidad de Max Weber
Javier E. Ortiz Cárdenas
Reencuentro , 2012,
Abstract: El acercamiento a Weber, como científico social, nos permite encontrar aportaciones teóricas, de método, enfoques y estudios comparativos para entender el funcionamiento de instituciones actuales, tal es el cometido del presente artículo.
Gestión de la información, modelos organizativos universitarios y la brecha digital
Javier E. Ortiz Cárdenas,Rogelio Martínez Flores
Reencuentro , 2008,
Abstract: Si es verdad que la información y el conocimiento son los principales factores generadores de valor, en este artículo intentamos precisar el sentido de la gestión de la información, su articulación con las formas organizativas universitarias y la vocación de estas mismas, en cuanto creadoras y transmisoras de conocimiento, además de comprender el importante papel que desempe a en la superación de la brecha digital existente en la sociedad y en la universidad misma.
Effect of Cholesterol Enriched or Fatty-Acid Diets on Cholesterol and Lipid Levels in Young Wistar Rats  [PDF]
Maribel Cortés-Ortiz, Perla Leal-Galicia, Benjamín E. Chávez-álvarez, María del Carmen Cárdenas-Aguayo, Marco Antonio Meraz-Ríos
Advances in Bioscience and Biotechnology (ABB) , 2014, DOI: 10.4236/abb.2014.510099
Abstract: Nutritional intake is a fundamental determinant of health. It is well known that cholesterol rich diets can induce several pathological conditions but detailed mechanism underlying these remains unknown. Wistar rats, an animal strain widely used in the research have been employed to study the effects of dietary interventions due to their metabolic characteristics, which are closer to the human compared to mice. The effect of some components of the western diet, combined with cholesterol in the lipid profile have been studied, but the impact of only cholesterol or fatty-acid diets in such a profile has not been yet characterized. Here we measured the effect of 6 or 16 weeks of dietary intervention with cholesterol enriched diet (CED) or fatty-acid diet (FAD) on cholesterol, triglyceride levels, high density lipoproteins (HDL) and low density lipoproteins (LDL). We observed significant differences in body weight only in animals treated with CED or FAD from Week 9 onwards as compared to animals fed the control diet. There were no differences between animals fed with CED or FAD in cholesterol levels at any time point nevertheless, triglyceride levels were significantly increased as compared to control diet in animals under both diets at early time points. Finally, both CED and FAD induced a decrease in HDL as compared to control levels in treatments of more than 6 weeks, whereas LDL transiently increased in animals treated with FAD from 10 to 12 weeks, but after this period LDL levels returned to baseline, suggesting that young rats have a compensatory effect at least for the period of time analyzed here. Here we provide a temporal course on lipid profile of cholesterol, triglycerides, HDL and LDH in Wistar rats treated with CED and FAD diet that can be useful as reference for future studies.
Balance de nitrógeno y fósforo de vacas lecheras en pastoreo con diferentes ofertas de kikuyo (Pennisetum clandestinum) suplementadas con ensilaje de avena (Avena sativa) Saldo de nitrogênio e fósforo a partir de vacas leiteiras em pastagem com diferentes ofertas de capim Kikuyu (Pennisetum clandestinum) silagem suplementada com aveia (Avena sativa) Nitrogen and phosphorus balance of cows offered different amounts of Kikuyu (Pennisetum clandestinum) and supplemented with oats (Avena sativa) silage
Javier M León,José E Mojica,Edwin Castro,Edgar A Cárdenas
Revista Colombiana de Ciencias Pecuarias , 2008,
Abstract: Nitrógeno (N) y fósforo (P) son elementos implicados en la contaminación ambiental. Con el objetivo de evaluar el balance de N y P se utilizaron 18 vacas bajo pastoreo en pasto kikuyo (Pennisetum clandestinum) en el Centro Agropecuario Marengo en Mosquera (Cundinamarca, Colombia). Los tratamientos consistieron en tres niveles (0, 0.7 y 1.4% del peso vivo) de oferta de ensilaje (MS) de avena (Avena sativa). Esta oferta diaria fue complementada con pasto kikuyo en pastoreo hasta alcanzar una oferta total del 4%. La relación kikuyo:ensilaje fue de 4:0, 3.3:0.7 y 2.6:1.4 para los tratamientos 1, 2 y 3, respectivamente. El ensilaje se suministró diariamente (AM y PM) en el potrero. Las vacas recibieron un alimento balanceado comercial a razón de 1kg por cada 4.2 kg de leche producida, y se mantuvo constante durante el periodo experimental que duró 14 días, con siete días de adaptación y siete de mediciones. La producción de leche (AM, PM) fue medida de manera individual; mientras que la producción de orina y heces fue medida los días 0, 7, y 14, para cuantificar N y P. El volumen de orina se estimó usando creatinina y el consumo usando cromo (cantidad de heces) y fibra en detergente acido indigerible (digestibilidad). El consumo de N (667.8 g/día) y la excreción en orina (240.6 g/d) fueron significativamente mayores (p<0.05) para el tratamiento 1 que para los tratamientos 2 (560.7 y 199.7 g/d) y 3 (594.8 y 200.8 g/d); sin embargo, no se encontraron diferencias estadísticas significativas (p>0.05) en la eficiencia de utilización de N (15.6; 16.6 y 15.1%, respectivamente). El consumo de P (98.2, 85.9, y 93.4 g/d), la excreción en orina (0.43, 0.39, y 0.48, g/d) y en heces (91.9, 100.7, y 108.6 g/d) no fueron estadísticamente diferentes entre tratamientos (p>0.05); sin embargo, el balance de P fue significativamente mayor (p<0.05) para el tratamiento 1 (5.9 g/d) que para los tratamientos 2 (-15.1g/d) y 3 (-15.6 g/d). Azoto (N) e fósforo (F) s o elementos envolvidos na polui o ambiental. Com o objetivo de avaliar o balan o de N e P foram usadas 18 vacas em pastagem de capim kikuyu grass (Pennisetum clandestinum) no Centro Agropecuario Marengo em Mosquera (Cundinamarca, Colombia). Os tratamentos consistiram de três níveis (0, 0.7 e 1.4% do peso corporal) lance silagem (MS) de aveia (Avena sativa). Essa oferta por dia foi complementado com pastagem Kikuyu em um lance de chegar a 4% do total da ra o. A rela o Kikuyu erva:silagem foi de 4:0, 3.3:0.7 e 2.6:1.4 para os tratamentos 1, 2 e 3, respectivamente. A silagem foi fornecida diariamente (AM e PM), no paddock.
Balance de nitrógeno y fósforo de vacas lecheras en pastoreo con diferentes ofertas de kikuyo (Pennisetum clandestinum) suplementadas con ensilaje de avena (Avena sativa)
León,Javier M; Mojica,José E; Castro,Edwin; Cárdenas,Edgar A; Pabón,Martha L; Carulla,Juan E;
Revista Colombiana de Ciencias Pecuarias , 2008,
Abstract: nitrogen (n) and phosphorus (p) have been implicated in environmental pollution. to evaluate n a p balance, eighteen lactating multiparous holstein cows grazing kikuyu in the livestock center marengo in mosquera (cundinamarca, colombia). the treatments consisting three allowances of oat silage 0, 0.7 and 1.4 kg/100 kg of body weight. this daily allowance was completed with kikuyu on grazing to obtain a total dry matter allowance of 4kg/100 kg of body weight. the kikuyu and silage ratio was 4:0; 3.3:0.7 and 2.6:1.4 for treatments 1, 2 and 3, respectively. cows received a commercial balanced feed 1kg for each 4.2kg of milk, and it was maintained during all the experimental period. this period lasted 14 days and consisted of 7 adaptation days and 7 experimental days. individual milk production was measured (am pm) and samples of urine and feces were taken on days 0, 7 and 14 to determine n and p. urine volume was estimated using creatinine and dry matter intake using chromium (feces volume) and indigestible acid detergent fiber (digestibility). n intake (667.8 g/d) and urine n excretion (240.6 g/d) was greater for cows on treatment 1 than for treatment 2 (560.7 and 199.7 g/d respectively) and for treatment 3 (594.8 and 200.8 g/d) respectively. however no differences were found on the efficiency of n utilization that was 15.6; 16.6 and 15.1 % for treatments 1, 2, and 3, respectively. daily p intakes (98.2; 85.9 and 93.4 g/d), p excretion in urine (0.43; 0.42; and 0.35 g/d) and p excretion in feces (91.8; 100.7 and 108.6) were not different between treatments, however phosphorus balance was positive and greater for cows on treatment 1 (5.9 g/d) than cows in treatments 2 and 3 (-15.5, and -15.6 g/d, respectively).
Infarto agudo del miocardio como primera manifestación del síndrome antifosfolípido primario en un paciente de veinticuatro a?os
Uribe,Carlos E; Cárdenas,Juan M; Cabrales,Jaime; Bohórquez,Ricardo; Roa,Nubia L; Beltrán,Javier; Urina,Manuel;
Revista Colombiana de Cardiología , 2005,
Abstract: primary antiphospholipid syndrome is usually manifested with deep venous thrombosis, pulmonary thromboembolism and arterial thrombosis, including cerebrovascular accidents. we report the case of a previously healthy young patient who suffered an acute myocardial infarction as the first manifestation of a primary antiphospholipid syndrome.
DIGITAL MAPPING OF FARMLAND CLASSES IN THREE LANDSCAPE IN MEXICO
G Cruz-Cárdenas,C.A Ortiz-Solorio,E Ojeda-Trejo,J.F Martinez-Montoya
Journal of Soil Science and Plant Nutrition , 2010,
Abstract: The cartography of farmland classes allows generating land maps, using a methodology based on local knowledge, rapidly and at low cost, and with a greater number of cartographic units than conventional soil surveys maps. However, the results found when producing these maps with automated cartography techniques are contrasting. Precision and accuracy were evaluated in 324 computer generated farmland class (FLC) maps by applying the Inverse Distance Weighted (IDW) interpolation model. These maps were obtained by varying the sample size for the training, its spatial design, and the Power value of the interpolator. Moreover, the effort needed to obtain maps with acceptable reliability was quantified. The procedure was applied to FLC maps obtained from surveys with producers from three contrasting environmental zones in Mexico. The results show that the best sampling scheme in the three areas is the systematic sampling, and Power 8, giving the maps with the highest reliability. Through the criterion of map reliability and effort needed for sampling, the recommended sample size is 10% to 25% of the total plots.
Antiprotozoal Activity of a Thymus vulgaris Methanol Extract and Its Fractions  [PDF]
Jesús Norberto Garza-González, Javier Vargas-Villarreal, Ma Julia Verde-Star, Catalina Rivas-Morales, Azucena Oranday-Cárdenas, Magda E. Hernandez-García, Laura De La Garza-Salinas, Francisco González-Salazar
Health (Health) , 2017, DOI: 10.4236/health.2017.97079
Abstract:
Introduction: Thymus vulgaris is used in traditional medicine to treat gastrointestinal diseases because of its antifungal, antibacterial, and antispasmodic activity. Objective: To verify whether Thymus vulgaris also has antiprotozoal activity against Trichomonas vaginalis, Giardia lamblia and Entamoeba histolytica trophozoites. Materials and methods: Conventional cultures of parasites were measured on the third day during the logarithmic growth phase. The antiprotozoal activity of the methanol extract and its fractions were evaluated comparing growth in cultures with and without extracts. Next, the extract was fractionated by polarity-based partitioning. Then, the purity of each fraction was determined by thin layer chromatography (TLC). The percentage of growth inhibition was calculated with respect to untreated controls. The 50% inhibitory concentration (IC50) of each extract was calculated by PROBIT analysis. Results: We found that a methanol extract of the aerial parts of Thymus vulgaris, at 300 μg/mL, inhibited the in vitro growth of G. lamblia and T. vaginalis, while E. histolytica growth was poorly inhibited. The methanol extract was further separated into mixtures of ursolic, oleanolic, and betulinic acids. The IC50 values of ursolic acid against G. lamblia and T. vaginalis were 8.12 μg/mL and 5.51 μg/mL, respectively. Conclusions: The methanol extract fraction containing ursolic acid obtained from Thymus vulgaris has antiprotozoal activity against G. lamblia and T. vaginalis trophozoites.
Scale of Teaching Strategies for Collaborative Learning: Design, Validation and Evaluation of Its Psychometric Properties in High School Education  [PDF]
Magaly Cárdenas Rodríguez, Luz Marina Méndez Hinojosa, César Alejandro Ortiz Páez
Psychology (PSYCH) , 2019, DOI: 10.4236/psych.2019.102019
Abstract: Most of the educational programs worldwide have focused on the diverse competences of the students, but in all of them, collaborative learning plays an important role. It is likely that many institutions are unaware of the teaching strategies that can produce collaborative learning in the classroom. Therefore, the present study aimed to design and evaluate the psychometric properties of a scale that examined the frequency of use of teaching strategies that led to collaborative learning in students. Nine subscales were designed, each one measuring a different strategy, these were evaluated by expert judgment and subsequently, they were applied to a sample of 200 high school teachers. Based on the data obtained, it is possible to provide evidence, through exploratory factor analysis and Cronbach’s alpha, of the instrument’s validity and reliability.
Page 1 /362477
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.