oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 103 )

2018 ( 639 )

2017 ( 647 )

2016 ( 877 )

Custom range...

Search Results: 1 - 10 of 377969 matches for " IVETTE HERNáNDEZ-LADRóN DE GUEVARA "
All listed articles are free for downloading (OA Articles)
Page 1 /377969
Display every page Item
Dispersión de semillas por aves en un paisaje de bosque mesófilo en el centro de Veracruz, México: Su papel en la restauración pasiva
HERNáNDEZ-LADRóN DE GUEVARA,IVETTE; ROJAS-SOTO,OCTAVIO R; LóPEZ-BARRERA,FABIOLA; PUEBLA-OLIVARES,FERNANDO; DíAZ-CASTELAZO,CECILIA;
Revista chilena de historia natural , 2012, DOI: 10.4067/S0716-078X2012000100007
Abstract: seed dispersal by birds may play a major role in the successful natural forest restoration process as birds can deposit pioneer and primary seeds species, thereby defining the recovery of plant community composition over time. in this study, seed ingestion and dispersion by frugivorous birds were analyzed as processes facilitating the restoration of tropical cloud montane forests in central veracruz, mexico. birds were classified according to their affinity to the forest and their preference to a particular forest stratum, in order to determine whether these factors were related to the richness, abundance and diversity of ingested and dispersed seeds. we analyzed 93 fecal samples from 23 bird species. a total of 2699 seeds from 17 plant species were found in the fecal samples, the most abundant seed was from the shrub conostegia xalapensis. we analyzed the correlation between seed size and beak size for the six most frequently captured bird species. we also evaluated the effect of bird ingestion on seed germination by performing two experiments, the first one using the total number of seeds found in fecal samples, and the second one using c. xalapensis seeds that were administered artificially to the birds and their germination compared with control seeds. we found significant differences among the ingested seed diversity indexes for the most commonly captured birds, which supports a differential seed consumption and dispersion. however, there were no significant differences of the seed abundance and richness between birds with different forest affinity or forest stratum preference. also, there was no significant association between seed size and the height and the width of the beak, but there was a difference found in the length measured from the base and from the nostrils. from the total seed species, 59 % germinated from fecal samples belonging to 78 % of the bird species. as has been suggested for lowland tropical forests, this study also showed that in tropical
Dispersión de semillas por aves en un paisaje de bosque mesófilo en el centro de Veracruz, México: Su papel en la restauración pasiva Seed dispersal by birds in a cloud forest landscape in central Veracruz, Mexico: Its role in passive restoration
IVETTE HERNáNDEZ-LADRóN DE GUEVARA,OCTAVIO R ROJAS-SOTO,FABIOLA LóPEZ-BARRERA,FERNANDO PUEBLA-OLIVARES
Revista chilena de historia natural , 2012,
Abstract: La dispersión de semillas por aves puede jugar un papel determinante en el éxito de la restauración pasiva de los bosques ya que las aves pueden depositar semillas de especies pioneras y primarias, definiendo con ello la recuperación de la composición de la comunidad vegetal en el tiempo. En este trabajo se analizó la ingesta y dispersión de semillas por aves frugívoras como coadyuvantes en la restauración del bosque mesófilo de monta a en el centro de Veracruz, México. Las aves fueron clasificadas de acuerdo a su afinidad por el bosque y al estrato arbóreo en que concentran su actividad, con el fin de determinar si estas características se relacionan con la abundancia, riqueza y diversidad de las semillas que ingieren y dispersan. Se analizaron 93 excretas de 23 especies de aves; en ellas se encontraron 2699 semillas de 17 especies vegetales, siendo las más abundantes las del arbusto Conostegia xalapensis. Analizamos la correlación entre tama o de las semillas y tama o del pico para las seis especies de aves más capturadas. Complementariamente, evaluamos el efecto de la ingesta de semillas por aves sobre la germinación, realizando dos experimentos, uno con el total de las semillas obtenidas en las excretas, y otro con semillas de C. xalapensis que fueron administradas a las aves artificialmente y su germinación comparada con semillas control. Se encontraron diferencias significativas entre los índices de diversidad de semillas ingeridas para las seis especies de aves con mayor número de registros, lo que sugiere un consumo diferencial. Sin embargo, no se encontraron diferencias significativas en la riqueza y abundancia de semillas consumidas entre aves con diferente afinidad al bosque y preferencia de estrato arbóreo. Tampoco se observó una asociación significativa entre el tama o de semillas con el ancho y lo alto del pico, pero sí con la longitud tomada desde la base y desde los nostrilos del mismo. Del total de las especies de semillas encontradas, el 59 % germinó en las excretas del 78 % de las especies de aves. Este trabajo muestra que en los bosques mesófilos de monta a las aves son agentes dispersores importantes de especies de plantas pertenecientes a bosques secundarios y también dispersores de algunas plantas del bosque primario, por ello son agentes que facilitan el proceso de sucesión forestal. Seed dispersal by birds may play a major role in the successful natural forest restoration process as birds can deposit pioneer and primary seeds species, thereby defining the recovery of plant community composition over time. In this study, seed inge
The Role of PET/CT Imaging in Lung Cancer  [PDF]
David Ladrón de Guevara Hernández
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.68076
Abstract: Lung cancer presents a high prevalence around the world and constitutes the leading cause of death due to cancer in men and women. Proper staging is essential in order to provide the correct treatment and estimate survival. PET/CT imaging is the method of choice for the staging of lung cancer patients with a better performance than the traditional imaging methods. It allows defining the primary tumor more clearly, separating it from the atelectasis and neighboring fibrotic changes, thus achieving an improved T evaluation while optimizing the target definition for radiotherapy. It presents greater sensibility and specificity than Computed Tomography (CT) when assessing the extra-thoracic and thoracic lymph nodes, modifying the N stage with regard to the traditional study in up to 25% of patients. PET/CT imaging is the method with the best performance for detecting extra-encephalic metastasis and for detecting unexpected lesions in up to 30% of patients. In order to achieve proper encephalic staging, a Magnetic Resonance Imaging scan must be performed or, a CT scan of the brain concomitant to the PET/CT. One to eight percent of lung cancer patients who are subjected to PET/CT imaging present a synchronous secondary extra pulmonary or pulmonary cancer when being diagnosed, with significant prognostic and therapeutic implications. PET/CT imaging has proven to be a valuable tool for survival prognosis with regard to the initial uptake of the tumor and the early response (interim) or final response to chemotherapy, although it is not routinely used for evaluating therapy. The PET/MRI is an emerging hybrid technique with certain advantages, such as less exposure to radiation in comparison to PET/CT and greater contrast resolution of the MRI images. However, its usefulness has not been validated yet for lung cancer patients.
Los pueblos indios en los libros de texto gratuitos
Pacheco Ladrón de Guevara, Lourdes C.;Navarro Hernández, María del Refugio;Cayeros López, Laura I.;
Revista mexicana de investigación educativa , 2011,
Abstract: this project presents an analysis of the way free textbooks address indian peoples and the implications for the formation of identity among students in basic education. evidence is given of the texts' unique view of indian peoples, since the construction of a homogeneous nation. a study was made of narrations that allude to the characteristics of today's indigenous population. the books used were the first- and second-grade books, and historia (2002) for the fourth and sixth grades, prior to the integral reform of basic education; as well as formación cívica y ética from the first and sixth grades, and the sixth-grade historia (2009), after the reform.
ACUTE TOXICITY OF AMMONIA ON Macrobrachium tenellum (SMITH) LARVAE
Gerardo FIGUEROA-LUCERO,María Cecilia HERNáNDEZ-RUBIO,Miguel de Jesús GUTIéRREZ-LADRóN DE GUEVARA
Revista internacional de contaminación ambiental , 2012,
Abstract: El langostino Macrobrachium tenellum es una especie potencial para cultivo, en México. El efecto del amonio en larvas se evaluó para proveer información básica de los niveles seguros para el cultivo en esta etapa de desarrollo. Un ensayo estático de 72 h se realizó con larvas de M. tenellum de cinco días de edad. Las concentraciones nominales probadas fueron desde 2.89 a 185 mg NH4-N/L, que equivalen a 0.103 hasta 6.585 mg NH3-N/L a 20 g/L de salinidad, 28 oC y pH 7.79. Las LC50 a 12, 24, 48 y 72 h fueron 2.939 ± 0.505, 0.749 ± 0.301, 0.477 ± 0.163 y 0.409 ± 0.068 mg NH3-N/L, respectivamente. Estos resultados sugieren que M. tenellum presenta una tolerancia ligeramente más alta al amonio en el estado de zoea que otras especies de langostinos y camarones.
Oncocitoma renal gigante
álvarez Ardura,M.; Hernández Ca?as,V.; Morena Gallego,J.M. de la; Rengifo Abbad,D.; González-Chamorro Ladrón de Guevara,F.; Llorente Abarca,C.;
Actas Urológicas Espa?olas , 2005, DOI: 10.4321/S0210-48062005000800013
Abstract: renal oncocytoma is a benign neoplasms arising from cells of the distal renal tubule. they acount for 3-7% of all renal tumors. most are incidental findings. differential diagnosis with renal cells carcinoma is often difficult. here we report a case of big renal oncocytoma as an incidental finding while performing an abdominal ultrasound in a patient with low abdominal pain. we also review the diagnostic an therapeutic approach in this kind of malignancies.
Abscesos amebianos de hígado: Tres a?os de experiencia
Nari,G. A.; Ceballos Espinosa,R.; Carrera Ladrón de Guevara,S.; Preciado Vargas,J.; Cruz Valenciano,J. L.; Briones Rivas,J. L.; Moreno Hernández,F.; Góngora Ortega,J.;
Revista Espa?ola de Enfermedades Digestivas , 2008, DOI: 10.4321/S1130-01082008000500004
Abstract: background: amebic liver abscess is frequently seen in endemic regions, and has a poor prognosis when diagnosis and treatment are inappropriate. aim: to evaluate and compare our own results; to propose a new classification and therapeutic algorithm. design: an observational and retrospective study. method: medical records were reviewed for sex, age, signs and symptoms, images, laboratory tests, size, location, treatment, hospital stay, and morbidity-mortality. results: sixteen patients with amebic liver abscess had been treated -9 were males, mean age was 30.56 years, all abscesses were solitary, 14 were in the right hepatic lobe, average size was 63.25, and 10 were of the collected type according to n’gbesso’s classification. seven patients had a good response to medical treatment, 6 needed percutaneous drainage, and 3 required surgery. morbidity was 12.5% and mortality 0%. average hospital stay was 7.68 days. conclusion: our results are similar to those in other published series. the addition of two new groups to n’gbesso’s classification provides better therapeutic orientation. we believe that early percutaneous drainage for collected abscesses bigger than 5 cm may improve symptoms and shorten hospital stay.
La comunicación en la seguridad del paciente The communication in patient's safety
Yoanna Cu?at Ladrón de Guevara,Eniomis Massó Betancourt,Gustavo Sánchez Fernández
Revista Cubana de Enfermer?-a , 2011,
Abstract:
Método de Balanceo de Rotores Rígidos con Datos de Vibración Pulsante
Alfonso C. García Reynoso,Miguel A. Cervantes Moya,José Camargo Méndez,Enrique Ladrón de Guevara Durán
Ingeniería mecánica, tecnología y desarrollo , 2008,
Abstract: Se aplica un método de balanceo dinámico de rotores rígidos para el caso de datos de vibración filtrada que varían en forma de pulsación debido a la presencia de armónicas de frecuencias muy cercanas entre sí. Para registrar estas variaciones se capturan los datos mediante un analizador virtual que recibe la se al de vibración y de la referencia temporal para calcular la amplitud y la fase en tiempo real. A partir del archivo de datos se aplica un método de balanceo que utiliza el promedio de la vibración en un ciclo completo de la pulsación. Este procedimiento se verifica en un banco de pruebas que consiste en dos ventiladores centrífugos de velocidades de operación casi iguales en los que se provoca la vibración pulsante. Los resultados de las pruebas de balanceo son satisfactorios.
Identidad y discurso contranormativos en El vampiro de la colonia Roma de Luis Zapata
Bertha LadróndeGuevara
Amerika : Mémoires, Identités, Territoires , 2011, DOI: 10.4000/amerika.1911
Abstract: El presente artículo analiza la identidad de Adonis García, protagonista de la novela en estudio, y el discurso de la misma como dos hechos primordiales bajo los que se fundamenta una crítica severa al sistema de género institucionalizado en México. La identidad de Adonis García muestra una triple presencia subversiva por tratarse de un homosexual/prostituto que, además, goza de su trabajo. Por otra parte, esta ruptura con el sistema de género hegemónico no puede realizarse con una argumentación filtrada a través del lenguaje usado por el dispositivo sexual institucionalizado; sino mediante una de-construcción del mismo y de la puesta en práctica de un discurso contra-hegemónico. Estos dos elementos –identidad y discurso– promueven un cuestionamiento a la forma de concebir el sujeto marginado por parte de los mecanismos del poder y, además, son subvertidos por Adonis García para construir, con base en su estatuto “ denigrado ”, una estrategia vital placentera y libertaria. This article analyzes the discourse and identity of Adonis García, the main character in the seminal work of Luis Zapata, El vampiro de la colonia Roma (1979), as two main venues used by its author to express a strong criticism against the institutionalized practice of gender relations in Mexico at the time of the publication of this foundational novel. The identity of Adonis García has a three dimensional subversion in the sense that he is not only openly homosexual, but also a male whore that frankly accepts he enjoys this kind of work. In order to represent this subversion in the hegemonic gender system, Zapata breaks with the official discourse and deconstructs its language, setting in its place a contra hegemonic discourse. Thus, identity and discourse in this novel are interwoven questioning the marginality of a gay man as represented in the official language and subverting its mechanisms of power. In the end, Adonis García builds trough this denigrated status a libertarian and festive strategy of life.
Page 1 /377969
Display every page Item


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