1,720,999 research outputs found
Expresión génica diferencial de catalasa y superóxido dismutasa en tejidos de la inflorescencia femenina y masculina y durante el crecimiento del tallo en maíz (Zea mays L.)
Get PDFFil: Acevedo, Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Expresión génica diferencial de catalasa y superóxido dismutasa en tejidos de la inflorescencia femenina y masculina y durante el crecimiento del tallo en maíz (Zea mays L.)
No full textFil: Acevedo, Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
A dichotomous key for the discrimination of the already known S-RNase alleles in potato species
No full textThe potato species exhibit gametophytic self-incompatibility system controlled by a single S-locus withmultiple S-haplotypes. Each S-haplotype carries two genetically linked genes, S-RNase and SLF, controllingthe female and male specificities, respectively. In the style, the S-RNase gene codes for an allele-specificribonuclease that is involved in the rejection of pollen that carries the same S-haplotype. This gene hasfive conserved regions (C1–C5) and two hypervariable domains located between C2 and C3 that play arole in S-RNase allele specificity. Presently, eight nucleotide sequences of S-RNase alleles from Solanumtuberosum and S. chacoense have been reported in potato species. In an effort to discriminate these S-RNase alleles and eventually detect new allelic variants, these sequences were analyzed by in silico PCR,using primers designed on the basis of four conserved regions, and were further examined by restrictionenzyme patterns. The development of the in silico approach led to the creation of a novel dichotomous keywhich was able to unequivocally identify the eight potato S-RNase alleles already known and eventuallydetect putative alleles when the size and/or the restriction pattern of the amplicons were different fromthose predicted. Experimental data validates the utility and efficiency of the dichotomous keyInstituto de SuelosFil: Marcellán, Olga. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Acevedo, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Residuos de cosecha con fines bioenergéticos : el rastrojo de maíz
Get PDFEl progresivo agotamiento de los combustibles fósiles convencionales sumado al aumento del consumo de energía y de las emisiones de gases de efecto invernadero ha demandado la búsqueda de fuentes de energía alternativas, renovables,
sustentables, eficientes, rentables y con menores emisiones. (Nigam y Singh, 2011). Durante la transición dos términos han adquirido significativa notoriedad: biomasa y biocombustibles. Se entiende por biomasa la fracción biodegradable de productos de
desecho y residuos procedentes de la agricultura, silvicultura y de las industrias relacionadas, así como de la fracción biodegradable de residuos industriales y municipales (Directiva 2003/30/CE). Desde un punto de vista de aprovechamiento energético, la biomasa se caracteriza por poseer bajo contenido en carbono y elevado contenido en oxígeno y en compuestos volátiles, estos últimos son los que concentran una gran parte del poder calorífico de la biomasa. Si bien el poder calorífico depende mucho del tipo de biomasa considerada y de su humedad, esta característica y el bajo contenido en azufre la convierten en un producto singularmente atractivo para ser aprovechado energéticamente. En tanto, se designan biocombustibles a los combustibles renovables que se producen a partir de materias primas de origen agropecuario, agro foresto industrial o desechos orgánicos, motivo por el cual constituyen una de las tantas formas de energías renovables. Su nivel de contaminación es menor que otros combustibles tradicionales, dado que su combustión no produce compuestos de azufre y sus emisiones de dióxido de carbono netas son prácticamente nulas. Por su estado, los biocombustibles se pueden clasificar en líquidos (bioetanol y biodiésel), gaseosos (biogás) y sólidos (pellets de madera, leña, briquetas de caña, etc.); en tanto que de acuerdo a la materia prima empleada para su elaboración los biocombustibles pueden ser de primera, segunda o tercera generación (Acevedo, 2013).Fil: Acevedo, Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; ArgentinaFil: Cruzate, Gustavo Adolfo. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; Argentin
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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