1,721,108 research outputs found
Biología de sistemas y su aplicación en biología celular y molecular
Full text linkFil: Mayorga, Luis.
Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Laboratorio de Biología Celular y Molecular IHEM-CONICET CCT
Cell bioenergetics: Simple logics, complex solution
Full text linkCells are open systems that exchange energy and molecules with their environment. As any material system, they perform all the complex activities required for homeostasis and reproduction, obeying the thermodynamic laws. This viewpoint will argue that the basic logic governing the energy flux required to preserve cell organization and function is simple: to decrease the activation energy (Ea) of specific processes. Almost none of the possible chemical reactions and energy transformations inside a cell occur at a measurable speed at room or body temperature. Enzymes or other macromolecular structures speed up particular transformations by decreasing the corresponding energetic barriers. However, to maintain the systems in a homeostatic state, capable of sophisticated functions based on this simple strategy requires an inconceivably complex solution. The conclusion will point to the challenging and intricate problems that cells have solved to carve the highly regulated channel through which the energy flows, fueling the work of these nanoscale machines.Fil: Mayorga, Luis Segundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Instituto de Histología y Embriología de Mendoza Dr. Mario H. Burgos; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Evaluation of corrosion resistance due to carbonation in concrete with portland cements blended with limestone and calcined clay
No full textilustraciones, fotografías (principalmente a color)El cemento pórtland adicionado con caliza y arcilla calcinada (LC3) es un material capaz
de desarrollar propiedades mecánicas comparables al cemento pórtland ordinario (OPC),
de permitir la obtención de una microestructura densa y rica en aluminatos que mejora la
resistencia del concreto al ataque por cloruros y la reacción álcali sílice (RAS), y trae
beneficios ambientales, técnicos y económicos a la sociedad. En este trabajo se evaluó la
resistencia a la corrosión debida a la carbonatación en concretos fabricados con cementos
LC3 encontrando que esta fue directamente proporcional al factor clínker del cemento,
particularmente en condición acelerada. Los cementos LC3 fueron formulados ajustando
su contenido de SO3 mediante la evaluación del proceso de hidratación en la pasta de
cemento. Las pruebas de carbonatación fueron ejecutadas mediante métodos acelerados
en la pasta, mortero y concreto, y también se desarrollaron pruebas en condición natural.
También, se estudió el efecto de la carbonatación sobre la resistencia a la compresión del
mortero, encontrando un buen desempeño para cementos con mayores factores clínker.
El estado del acero de refuerzo en concretos expuestos a carbonatación natural y
acelerada fue evaluado mediante las técnicas electroquímicas de resistencia a la
polarización lineal (LPR) y espectroscopia de impedancia electroquímica (EIS),
evidenciando que los efectos de la carbonatación acelerada en la reducción de la
resistencia eléctrica de los concretos LC3 y la presencia de corrosión del acero inician
antes de que el frente de carbonatación alcance la superficie de la barra de acero.
Adicionalmente, la evaluación de la corrosión mostró que los concretos con cementos
adicionados en grandes proporciones son más vulnerables a la corrosión debida a la
carbonatación, existiendo un mayor riesgo en aquellos con menores factores clínker. (Texto tomado de la fuente)Portland cement blended with limestone and calcined clay (LC3) is a material capable of developing mechanical properties comparable to ordinary Portland cement (OPC), allowing a dense microstructure rich in aluminates to be obtained that improves the resistance of concrete to attack by chlorides and the alkali silica reaction, and brings environmental, technical and economic benefits to society. In this work, the resistance to corrosion due to carbonation in concrete made with LC3 cements was evaluated finding that it was directly proportional to the clinker factor of the cement, particularly in the accelerated condition. LC3 cements were formulated by adjusting their SO3 content by evaluating the hydration process in the cement paste. Carbonation tests were carried out using accelerated methods on paste, mortar and concrete, although tests were also carried out in natural conditions. Also, the effect of carbonation on the compressive strength of the mortar was studied, finding a good performance for cements with higher clinker factors. The state of reinforcing steel in concrete exposed to natural and accelerated carbonation was evaluated by electrochemical techniques of linear polarization resistance (LPR) and electrochemical impedance spectroscopy (EIS), showing that the effects of accelerated carbonation on the reduction of the electrical resistance of the LC3 concrete and the presence of steel corrosion begin before the carbonation front reaches the surface of the steel bar. Additionally, the corrosion evaluation showed that concretes with cements blended in large proportions are more vulnerable to corrosion due to carbonation, with a higher risk in those with lower clinker factors.MaestríaMagister en Ingeniería - EstructurasMateriales para construcció
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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