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Search Results: 1 - 10 of 14126 matches for " Martha Elena; "
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La subjetividad en la formación de maestros
Baracaldo Quintero,Martha Elena;
Nómadas , 2011,
Abstract: this article tackles the inclusion of some care of the self mechanisms in the teachers' education to generate pedagogical practices suitable to educate subjectivity. it tends to examine the relationships among desk, copybook, and board as well as show the way in which such relations configure school subjects. under this assumption some effects are described and a series of questions are stated about the chances of tackling subjectivity taking into account the variations in the use of these devices.
ANáLISIS COMPARATIVO DE LA LLUVIA DE SEMILLAS DE Gaiadendron punctatum (LORANTHACEAE) Y Ternstroemia meridionalis (THEACEAE) EN EL PARQUE NATURAL MUNICIPAL RANCHERíA (BOYACá), COLOMBIA
Parada Quintero Martha Elena
Acta Biológica Colombiana , 2012,
Abstract: Gaiadendron punctatum y Ternstroemia meridionalis son especies ornitócoras del bosque altoandino, la primera abundante en Ranchería, y la segunda casi extinta localmente. Se evaluó la lluvia de semillas, establecimiento de plántulas y fenología de la fructificación de G. punctatum y T. meridionalis. El muestreo se realizó entre marzo a diciembre de 2010 que incluye la época seca y lluviosa; se instalaron 8 trampas, con una superficie de recolección de 1 m2, y 4 parcelas de 3x3 m. La fructificación de las dos especies fue continua, con alto porcentaje de frutos inmaduros, la mayor fructificación se presentó en época lluviosa. Las dos especies presentaron lluvia de semillas durante todo el estudio, G. punctatum presentó más alta lluvia de semillas con un promedio de 169/m2, mientras T. meridionalis 50 semillas/m2. La mayor abundancia de semillas de G. punctatum se presentó en la época seca, para T. meridionalis fue en la época lluviosa. A pesar de la baja lluvia de semillas, T. meridionalis mostró alto porcentaje de semillas viables. G. punctatum presentó mayor número de plántulas que T. meridionalis con 22 y 9 plántulas en 9 m2, respectivamente. G. punctatum presentó mayor presión de propágulos, lo que explicaría el alto número de individuos en el área. Aunque el número de semillas y plántulas de T. meridionalis no es muy alto, representa un potencial para la prevalencia de esta especie y la necesidad de buscar los factores que impiden la persistencia de estos propágulos.
La Psicología Política: El Eslabón Perdido en Tiempos de Crisis
Pérez Gaviria,Martha Elena;
Psychologia. Avances de la Disciplina , 2012,
Abstract: this paper presents a reflection on the development and application fields of political psychology and how, in the face of modern times, this knowledge could contribute to the understanding of vital issues affecting the lives of people. presents some considerations about their background, conceptualization and issues, then analyze the agendas worked and the proposed agendas for both the strengthening of political psychology, and the study of issues that demand response, we conclude that this is an area that requires a new agenda for strengthening the discipline and to tackle the different problems from new rationales to explain the complexity of these phenomena. we conclude that this area of psychology has gone through fundamental questions that respond to complex phenomena of political behavior, as is necessary to create a new agenda that confronts phenomena such importance, such as those relating to the psychology of war , the indifference of citizens, globalization and its impact on individual behavior.
Migración internacional y cafeticultura en Veracruz, México
Martha Elena NAVA-TABLADA
Migraciones internacionales , 2012,
Abstract: El sector cafetalero veracruzano actualmente enfrenta una crisis por la caída de los precios en el mercado mundial, que ha originado el aumento de la migración internacional. En este contexto, se analizaron los cambios que esta migración ha propiciado en las unidades de producción de café de la región de Coatepec, Veracruz. Para ello se aplicaron 56 cuestionarios a fami lias cafeticultoras con experiencia migratoria. Los principales cambios en las unidades de producción de café relacionados con la migración fueron: intensificación de las la bores para los que permanecen en la comunidad, aumento en la contratación de peones, abandono del cafetal, menor manejo tecnológico y sustitución del cafetal por monocultivos. En conclusión, la migración propicia el estancamiento, disminución o abandono de la cafeticultura.
Melanina: implicaciones en la patogénesis de algunas enfermedades y su capacidad de evadir la respuesta inmune del hospedero
Urán,Martha Eugenia; Cano,Luz Elena;
Infectio , 2008,
Abstract: melanin is one of the common pigments in nature; it is responsible for pigmentation in plants and animals. it is found in skin, eyes, feathers, egg shell, hair, insect cuticle, cuttlefish ink and wall and/or cytoplasm from many microorganisms. melanin in humans is also present in substantia nigra and hepatocytes. some microorganisms that have been reported producing melanin are: vibrio cholerae, mycobacterium leprae, bacillus thurigiensis, pseudomonas aeruginosa, schistosoma mansoni, fasciola gigantita, trichuris suis, alternaria alternata, aspergillus niger, blastomyces dermatitidis, candida albicans, cladosporium carionii, coccidioides immitis, cryptococcus neoformans, exophiala (wangiella) dermatitidis, fonsecaea pedrosoi, histoplasma capsulatum, paracoccidioides brasiliensis, penicillium marneffei, pneumocystis carinii (jirovecii), scedosporium prolificans, scytalidium dimidiatum, sporothrix schenckii, and most of the dematiaceous fungi. this review is focused on recent international publications concerning melanin analysing its capacity to survive in nature and during infection inside the host and its evasion of the immune response. melanin acts as an inmunomodulador particle and it is known that its presence in many of microorganisms could protect them from microbicidal agents presently used.
Melanina: implicaciones en la patogénesis de algunas enfermedades y su capacidad de evadir la respuesta inmune del hospedero Melanin: implications in some disease pathogenesis and its capacity to evade the host immune response
Martha Eugenia Urán,Luz Elena Cano
Infectio , 2008,
Abstract: La melanina es uno de los pigmentos más comunes y de mayor distribución en la naturaleza. Es responsable de la coloración de plantas y animales; se encuentra en los ojos, el cabello, la piel, el plumaje, la cáscara de los huevos, la cutícula de los insectos, la tinta de los cefalópodos y en la pared y el citoplasma de muchos microorganismos. En los humanos este pigmento se ha encontrado también fuera de la piel, en las neuronas de la sustancia nigra y en los hepatocitos. Entre los microorganismos que se han reportado como productores de melanina tenemos Vibrio cholerae, Mycobacterium leprae, Bacillus thurigiensis, Pseudomonas aeruginosa, Schistosoma mansoni, Fasciola gigantita Trichuris suis, Alternaria alternata, Aspergillus niger, Blastomyces dermatitidis, Candida albicans, Cladosporium carionii, Coccidioides immitis, Cryptococcus neoformans, Exophiala (Wangiella) dermatitidis, Fonsecaea pedrosoi, Histoplasma capsulatum, Paracoccidioides brasiliensis, Penicillium marneffei, Pneumocystis carinii (jirovecii), Scedosporium prolificans, Scytalidium dimidiatum y Sporothrix schenckii; esto sin tener en cuenta los hongos dematiáceos, entre muchos otros. Esta revisión pretende hacer un compendio de las más recientes publicaciones sobre melanina relacionadas principalmente con su función, su importante contribución a la supervivencia en el ambiente y durante la infección, como factor de virulencia en diversos microorganismos, principalmente en hongos patógenos, y su papel como agente inmunomodulador, así como la reducida susceptibilidad que confiere contra muchos de los antimicóticos usados en la actualidad. Melanin is one of the common pigments in nature; it is responsible for pigmentation in plants and animals. It is found in skin, eyes, feathers, egg shell, hair, insect cuticle, cuttlefish ink and wall and/or cytoplasm from many microorganisms. Melanin in humans is also present in substantia nigra and hepatocytes. Some microorganisms that have been reported producing melanin are: Vibrio cholerae, Mycobacterium leprae, Bacillus thurigiensis, Pseudomonas aeruginosa, Schistosoma mansoni, Fasciola gigantita, Trichuris suis, Alternaria alternata, Aspergillus niger, Blastomyces dermatitidis, Candida albicans, Cladosporium carionii, Coccidioides immitis, Cryptococcus neoformans, Exophiala (Wangiella) dermatitidis, Fonsecaea pedrosoi, Histoplasma capsulatum, Paracoccidioides brasiliensis, Penicillium marneffei, Pneumocystis carinii (jirovecii), Scedosporium prolificans, Scytalidium dimidiatum, Sporothrix schenckii, and most of the dematiaceous fungi. This review is
Retention of Memory through Metamorphosis: Can a Moth Remember What It Learned As a Caterpillar?
Douglas J. Blackiston, Elena Silva Casey, Martha R. Weiss
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0001736
Abstract: Insects that undergo complete metamorphosis experience enormous changes in both morphology and lifestyle. The current study examines whether larval experience can persist through pupation into adulthood in Lepidoptera, and assesses two possible mechanisms that could underlie such behavior: exposure of emerging adults to chemicals from the larval environment, or associative learning transferred to adulthood via maintenance of intact synaptic connections. Fifth instar Manduca sexta caterpillars received an electrical shock associatively paired with a specific odor in order to create a conditioned odor aversion, and were assayed for learning in a Y choice apparatus as larvae and again as adult moths. We show that larvae learned to avoid the training odor, and that this aversion was still present in the adults. The adult aversion did not result from carryover of chemicals from the larval environment, as neither applying odorants to na?ve pupae nor washing the pupae of trained caterpillars resulted in a change in behavior. In addition, we report that larvae trained at third instar still showed odor aversion after two molts, as fifth instars, but did not avoid the odor as adults, consistent with the idea that post-metamorphic recall involves regions of the brain that are not produced until later in larval development. The present study, the first to demonstrate conclusively that associative memory survives metamorphosis in Lepidoptera, provokes intriguing new questions about the organization and persistence of the central nervous system during metamorphosis. Our results have both ecological and evolutionary implications, as retention of memory through metamorphosis could influence host choice by polyphagous insects, shape habitat selection, and lead to eventual sympatric speciation.
Descripción del cráneo de Bramocharax caballeroi Contreras & Rivera 1985 (Pisces, Characidae), pez endémico del Lago de Catemaco, Veracruz, México
Valdez-Moreno, Martha Elena;Contreras-Balderas, Salvador;
Hidrobiológica , 2009,
Abstract: the bramocharax genus is distributed from central america to mexico. until now the species known are bramocharax bransfordi collected in nicaragua and costa rica, b. dorioni and b. baileyi from guatemala and b. caballeroi from catemaco lake, veracruz, mexico. the aim of this work is to realize a detailed description of the skull for bramocharax caballeroi from the analysis of 37 different topotypes. the skull of this species has 58 osteological elements, 49 of them coupled. shape is oval in lateral view, because the bones of the snout (ethmoid, vomer, lateral ethmoid, dentary, maxillae, premaxillae, ecto and mesopterygoids) and the frontal and circunorbitals are elongated. the dorsal margin is slightly concave and the anterior part is elongated. in specimens less than 80 mm, all the bones are smoother, with more regular edges. with the age increase, they become more robust with more irregular edges. a comparison of s the skull between b. caballeroi and astyanax mexicanus resulted in 25 bones with differences, while with astyanax fasciatus, main contrasts were the supraoccipital length, the shape of the opercles and the infraorbital 3. in addition there are important differences in the dentition, gill rackers, as well as suspensory pharingeals and pharyngeal plates with respect to astyanax.
MéTODO AUTOMáTICO DE REGISTRO PARA LA EVALUACIóN DE LA MINERALIZACIóN óSEA POSQUIRúRGICA
MA?ANA,GABRIEL; ROMERO,EDUARDO; FORERO,MARTHA ELENA;
Revista Med , 2007,
Abstract: digital subtraction is a common technique used in radiological studies of periapical lesions and other dental disorders, where treatment has to be evaluated over time. this paper shows a fast and reliable registration method for subtracting two digitized radiographs showing an unpredicted mismatch. an optimal affine transformation is found using an adaptive genetic algorithm (ga) as the optimizing strategy and a correlation ratio as the similarity measure. when processing pairs of standard intra-oral radiographs, the parallel ga implemented takes advantage of the cpu idle cycles of a computational grid, resulting in an application that exploits an existent infrastructure with a computational time of twenty seconds. by using an existing hardware infrastructure and software of free distribution, the proposed approach can be used in public hospitals and other institutions carrying low budget. the validation process shows that there are not significant differences between the automatic system and the manual registration. the results show that in endodontic surgery the technique of digital radiographic subtraction is a determining tool in the evaluation of post-surgical bone mineralization. furthermore, it will be useful in clinical environments where there is not viable to follow a standardization protocol.
SIMBIOSIS MICORRIZICA ARBUSCULAR Y ACUMULACIóN DE ALUMINIO EN Brachiaria decumbens Y Manihot esculenta
GUERRA S.,BEATRIZ ELENA; CHACóN V.,MARTHA ROCIO;
Biotecnología en el Sector Agropecuario y Agroindustrial , 2012,
Abstract: oil palm (elaeis guineensis jacq) soils from-santander puerto wilches-colombia, have low fertility, high aluminum saturation and low density of mycorrhizal fungal spores. behavior mycorrhizal symbiosis was evaluated using native soils with mycorrhizae (ma +) and sterile soils without mycorrhizae (ma -) using brachiaria decumbens and manihot esculenta, both plants have high mycotrophy and ion binding capacity of aluminum. variables were spore density, percentage of mycorrhizal colonization, biomass and root length, concentration of aluminum at leaf and root. was performed (anova) with a two-way general linear model. there were mycorrhizal colonization rates exceeding 70% in b. decumbens in soils with concentrations of 0,6 and 1,4 meq/100 g of aluminum. m. esculenta established mycorrhization at 50% in all four soils. spores were increased up to 200% in the two hosts plants. aluminum concentrations were higher in mycorrhizal roots, while leaf-level values were lower.
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