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Search Results: 1 - 10 of 32912 matches for " Daniel Leobardo; Valadez-Moctezuma "
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Detección de geminivirus asociados a la alstroemeria (alstroemeria l.) En villa guerrero, estado de México
Cervantes-Díaz,Lourdes; Zavaleta-Mejía,Emma; Rojas-Martínez,Reina Isabel; Alanís-Martínez,Iobana; Ochoa-Martínez,Daniel Leobardo; Valadez-Moctezuma,Ernestina; Grimaldo-Juárez,Onécimo;
Interciencia , 2009,
Abstract: in alstroemeria (alstroemeria l.) plantations located in villa guerrero, mexico state, plants with symptoms similar to those induced by geminivirus in other horticultural crops have been detected. in addition, the presence of whiteflies, which are considered the most efficient vectors of these viruses, has been observed in these plantations. the goal of this work was to detect the presence of this geminivirus species in alstroemeria plants. by means of pcr analysis using primers motcp2118/motcp2123, a fragment of ~600pb similar to the amplicon obtained from phyvv-infected positive control was amplified only from symptomatic plants. nicotiana glutinosa, n. benthamiana, n. rustica, n. tabacum var. xanthi and datura stramonium plants were inoculated by bombardment with total dna obtained from symptomatic alstroemerias and positive to phyvv by means of pcr. inoculated plants showed mild mosaics and deformation of leaves, whereas in the leaves of capsicum annum plants, mosaics, vein necrosis and blisters were observed. using dna from these plants as template in pcr, amplicons corresponded to phyvv were also obtained; however, in bombarded monocotyledons, including alstroemeria, this fragment was not detected. the sequence of oligonucleotides from the pcr products showed 98% homology to phyvv geminivirus. even though symptoms presented by alstroemeria plants in the field were not reproduced, the presence of a geminivirus similar to phyvv in tissue of symptomatic plants was evidenced through pcr.
Caracterización de ADN de clones de papa e identificación de fitoplasmas asociados al síndrome de la punta morada
Alarcón-Rodríguez, Norma M.;Lozoya-Salda?a, Héctor;Valadez-Moctezuma, Ernestina;
Agrociencia , 2009,
Abstract: in many potato growing areas in méxico, there is presence of purple top syndrome, which reduces the yield and quality of this tuber. a main factor of this syndrome is the presence of phytoplasms and inadequate management of its insect vector. one option for controlling this disease is to generate resistant potato genotypes and early diagnosis to prevent its disemination. therefore, the objectives of the present study were to detect phytoplasms associated with purple top present in asymptomatic potato clones, but which were exposed to the disease for four seasons, and to identify the host-pathogen relationship. at the end of the 2005 growing season, leaves of 18 asymptomatic potato clones, in toluca, state of méxico, were collected, originating from two breeding programs of the united states department of agriculture (usda/ars). also included were the alpha cultivar with symptoms of the disease as positive control and plants free of phytoplasm. the detection of the pathogen was made with direct pcr, nested pcr and rflp markers, using the enzymes alu 1, hinf 1, kpn 1, eco r1, tru 9, taq 1, and identifying the presence of three groups of phytoplasm in all of the clones. the clones were clustered in three groups related to the positive control, using five primers of rapds markers. a limited specific host-pathogen relationship was detected as a function of the dna fingerprints of both host and pathogen.
Variación de la región ribosómica nuclear en Crataegus L. del centro y sur de México
Nú?ez-Colín,Carlos Alberto; Valadez-Moctezuma,Ernestina; Barrientos-Priego,Alejandro Facundo; González-Andrés,Fernando; Nieto-ángel,Raúl;
Agronomía Mesoamericana , 2011,
Abstract: variation of the nuclear ribosomal region in crataegus l. from central and southern mexico. this study was conducted at the universidad autónoma de chapingo and concluded in october 2008, to determine the genetic relationships among species of crataegus from central and southern mexico. the variation in the sequences of the nuclear ribosomal region was low in all accessions of germplasm of mexican crataegus, and the phylogram only showed separation of the species used as positive controls, but did not show a clear separation of groups of species. however, all accessions had the same pattern of nucleotide substitution and very low values of the distance of nucleotide composition; thus, mexican crataegus species have high genetic relationship among them, but there is a lack of evidence to conclude that they are variants of the same taxonomic species. c. nelsoni and c. stipulosa could be a source of genes for c. mexicana because both species, from chiapas, have the closest relationship with this species, which has the best agronomic characteristics.
VARIACIóN DE LA REGIóN RIBOSóMICA NUCLEAR EN CRATAEGUS L. DEL CENTRO Y SUR DE MéXICO
Carlos Alberto Nú?ez-Colín,Ernestina Valadez-Moctezuma,Alejandro Facundo Barrientos-Priego,Fernando González-Andrés
Agronomía Mesoamericana , 2011,
Abstract: Este estudio fue realizado en la Universidad Autónoma Chapingo y concluido en octubre de 2008 y tuvo como objetivo determinar las relaciones genéticas entre especie s de Crataegus del centro y sur de México. La variación en las secuencias de la región ribosómica nuclear fue baja en todas las accesiones de germoplasma de Crataegus mexicanos, y el filograma sólo mostró separación de las especie s usadas como controles positivos, pero no mostró una clara separación de grupos de especie s. Si n embargo, todas las accesiones tuvie ron un mismo patrón de sustitución de nucleótidos y muy bajos valores en la distancia de composición de nucleótidos; por lo que las especie s mexicanas de Crataegus mostraron alta relación genética, pero falta evidencia para concluir que son variantes de una misma especie taxonómica. C nelsoni y C. stipulosa pueden ser una fuente de genes para C. mexicana porque ambas especie s, originarias de Chiapas, tie nen la más estrecha relación con esta especie , que es la que presenta las mejores características agronómicas.
Técnicas moleculares para la caracterización de genomas vegetales (garbanzo) y algunas aplicaciones potenciales
Ernestina Valadez Moctezuma,Gu00FCnter Kahl,Juliane Ramser,Bruno Hu00FCttel
Revista fitotecnia mexicana , 2001,
Abstract:
Variabilidad morfológica y molecular de cultivares criollos y mejorados de frijol común en Tabasco, México
Abel Vidal-Barahona,Luz del Carmen Lagunes-Espinoza,Ernestina Valadez Moctezuma,Carlos Fredy Ortiz-Garcu00EDa
Revista fitotecnia mexicana , 2006,
Abstract: La variabilidad genética entre siete cultivares criollos de frijol común (Phaseolus vulgaris L.) colectados en la región de la Chontalpa, Tabasco, México, y 14 cultivares mejorados fue evaluada con marcadores morfológicos y moleculares tipo RAPD e ISSR. Un alto nivel de cercanía entre los dos tipos de cultivares para las 19 características morfológicas evaluadas fue establecido por el análisis de componentes principales. Los genotipos criollos se asociaron con los mejorados. Entre los cultivares criollos, Frijol Pondoy , Frijol Negro, criollos 16 y 17 y Dos meses mostraron una estrecha cercanía a nivel espacial, relacionada con las variables peso de biomasa aérea, tasa de crecimiento de la semilla y proporción de pericarpio, principalmente. El análisis de agrupamiento basado en los datos de similitud genética de marcadores RAPD-ISSR estimada con el coeficiente de Dice, mostró una baja variabilidad entre genotipos. Así, a nivel intraespecie de P. vulgaris el grado de parentesco entre genotipos de frijol negro evaluados es alto; la diferencia entre ellos es de 6 %, lo que indica que los cultivares criollos de la región tienen ancestros en común con las variedades mejoradas o líneas utilizadas en los programas de mejoramiento genético del frijol negro en el país y que han adquirido una adaptación especial a las condiciones húmedas de Tabasco, producto de la selección ejercida por los agricultores de la región.
DIVERSIDAD GENéTICA EN MéXICO DE VARIEDADES NATIVAS DE CHILE 'POBLANO' MEDIANTE MICROSATéLITES
Aremi R. Contreras Toledo,Higinio Lu00F3pez Su00E1nchez,Amalio Santacruz Varela,Ernestina Valadez Moctezuma
Revista fitotecnia mexicana , 2011,
Abstract: La domesticaci n del chile (Capsicum annuum L.) se efectu en M xico, gracias a lo cual se encuentra una gran riqueza de variedades en el pa s. En el centro del pa s se encuentra distribuido el chile 'Poblano', que no es consumido por su contenido de capsaicina, como la mayor a de las especies del g nero, sino como ingrediente principal de platillos tradicionales. Este estudio se hizo para describir los diferentes grupos gen ticos que forman las variedades, determinar sus posibles patrones de distribuci n de diversidad, analizar la estructura gen tica de las poblaciones de chile 'Poblano' y su relaci n con otros tipos de chile. Se evaluaron 55 poblaciones de chile 'Poblano', 2 de 'Loco', 2 de 'Miahuateco' y 3 de 'Ancho', colectadas en el Valle de Puebla, Tehuac n, Puebla y Rancho Grande, Zacatecas, m s un h brido comercial como testigo. Se utilizaron 19 loci de microsat lites (SSR) y se calcularon los par metros de diversidad gen tica, proporci n de loci polim r cos, ndice de heterocigosidad y estad sticos de F de Wright; adem s, se hicieron an lisis de componentes principales y de conglomerados. Se detectaron 105 alelos en total, con un promedio de 5.53 alelos por locus y 80 % de loci polim r cos. Las variedades locales destacaron por ser las de mayor polimor smo y heterocigosidad. El estad stico FST de diferenciaci n gen tica fue de 0.108, que indica que 89.2 % de la variaci n se encuentra dentro de las poblaciones. Hubo mayor diferenciaci n en los tipos 'Poblano', 'Ancho' y 'Loco'. Las diferentes poblaciones formaron grupos de nidos con cierta dispersi n dentro del tipo 'Poblano'. Se detect alta diferenciaci n entre las variedades provenientes del Valle de Puebla, Tehuac n y Zacatecas, aparte del h brido comercial. La complejidad gen tica fue mayor en las variedades locales, que no presentaron un patr n de distribuci n.
Partial boundary regularity for co-dimension one area-minimizing currents at immersed $C^{1,α}$ tangential boundary points
Leobardo Rosales
Mathematics , 2015,
Abstract: We give partial boundary regularity for co-dimension one absolutely area-minimizing currents at points where the boundary consists of a sum of $C^{1,\alpha}$ submanifolds, possibly with multiplicity, meeting tangentially, given that the current has a tangent cone supported in a hyperplane with constant orientation vector; this partial regularity is such that we can conclude the tangent cone is unique. The proof follows closely the boundary regularity result given by Hardt and Simon in [9].
El movimiento urbano popular mexicano
Pedro Moctezuma
Nueva antropología , 1984,
Abstract:
Relationship between the Environment and Economic Growth in China via Exports: A Perspective of Ecological Impact (2000-2014)  [PDF]
Guillermo Velázquez Valadez, Jiaqi Hu
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.711136
Abstract:
China’s swift and substantial economic growth over the past 20 years has made the country one of the top industrial powers in the world, second only the United States. From the perspective of ecology and the impact on the environment produced by economic and industrial growth, the exports that have driven rapid growth have also resulted in an alarming level of environmental pollution in major Chinese cities. Research has shown that the Chinese government’s investment in bringing down pollution levels has been insufficient and ineffective. The monetary amount allocated for pollution reduction has barely reached 0.15% of the country’s GDP and has failed to meaningfully reverse the effects of industrialization, including increased exports and economic growth rates affecting China’s ecology. The present study investigated China’s ecological situation in terms of the industrial production that has generated its level of exports, with special focus on problems related to water, air, and solid waste. An econometric analysis was conducted to determine the relationship between the main variables. The exports and GDP (dependent variable), air pollution, water pollution, and industrial solid waste (independent variables) were provided by the Institute of Statistics and the Environment Institute of China for this study. The data was managed in Econometric Eviews 7.0 software and yielded an adjusted R2 of 96.09% (high correlation) with an interesting correlation between the exports and three independent variables; after subsequent variable analysis, we found that investments in water and industrial solid waste were not significant (i.e., that said investments have failed to solve the pollution problem). It is necessary to review the Chinese investment policy with special attention to these variables to appropriately respond to China’s ecological crisis.
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