1,720,961 research outputs found
INFLUENCIA DE LA DIETA EN EL ANIMAL DONADOR PARA ESTUDIOS DE DIGESTIBILIDAD IN VITRO, PARA DETERMINACION DE EFECTOS PROBIOTICOS DE CULTIVOS FUNGICOS
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ESTUDIO Y MODELAMIENTO MATEMATICO DE LA BIODEGRADACION DE HIDROCARBUROS EN BIORREACTORES HETEROGENEOS
Get PDFSe desarrollaron dos modelos para la predicción en la biodegradación de hidrocarburos en biorreactores heterogéneos. El primer modelo se baso en las biorreacciones de consumo de sustrato y formación de productos que suceden en la fase líquida acuosa, y el transporte por convección de hidrocarburos y oxígeno en interfases líquido-líquido y líquido-gas respectivamente. Este primer modelo fue capaz de describir la biodegradación de una mezcla de crudo maya parafinas en un biorreactor de dos fases no miscibles líquido-líquido (BLL). El modelo también permitió proyectar el comportamiento del BLL bajo diferentes condiciones de operación bióticas y abióticas. Por otra parte, la operación secuencial durante 20 ciclos y en condiciones de limitación de oxígeno del BLL, permitió mejorar la capacidad de un consorcio microbiano para biodegradar una mezcla de crudo maya y parafinas, produciendo un patrón de biodegradación estable a partir del cuarto ciclo de operación del birreactor. Además, el consorcio microbiano proveniente del BLL fue capaz de biodegradar y mineralizar sin inhibición, a una mezcla hidrocarburos totales del petróleo libre de asfaltenos. Se llevaron a cabo estudios de consumo de potencia y suspensión de sólidos para el biorreactor de lodos (BLD) utilizado en la biodegradación de hidrocarburos totales del petróleo de un suelo con un alto nivel de intemperización. Los estudios mostraron que un impulsor de flujo descendente con paletas planas y 45° de inclinación, fue el que presento el mejor desempeño en lo referente al consumo de potencia y suspensión efectiva de sólidos. Simultáneamente, se llevaron a cabo estudios en el transporte por convección de oxígeno en el BLD, determinándose que para cargas de sólidos hasta de un 10% p/v, los intervalos en los valores de la velocidad del impulsor (N min-1) y gasto de aire (Q L min-1), en los que se alcanzaron los valores más altos del coeficiente volumétrico de
e transferencia de oxígeno (kLa h-1) fueron 425≤N≤445 y 5.25≤Q≤6.25. El segundo modelo desarrollado fue de difusión-sorción-biodegradación (DSB). El modelo fue capaz de predecir y describir la biodegradación de hidrocarburos totales del petróleo en el BLD para el suelo intemperizado en estudio. El modelo consideró un fenómeno de histéresis en los poros al interior de las partículas de suelo, en donde la trayectoria del equilibrio inicial de des-adsorción y solubilización de los HTPs (isoterma lineal), fue diferente a la trayectoria de un segundo equilibrio de re-adsorción (isoterma de Langmuir). El considerar para el segundo equilibrio una isoterma de tipo Langmuir, permitió explicar de manera clara el fenómeno de difusión retardada. Los modelos desarrollados pueden usarse como plataformas para la creación de criterios de diseño, así como para la determinación de las mejores condiciones de operación para la biodegradación de hidrocarburos mediante biorreactores heterogéneos.
Two models to predict the hydrocarbon biodegradation in heterogeneous bioreactors were developed. The first model was supported in liquid aqueous phase bioreactions such as substrate uptake and product formation, and hydrocarbons and oxygen convection transport in the liquid-liquid and liquid-gas interphases respectively. This first model was capable to describe the biodegradation of Maya crude oil-paraffin mixture in a two no miscible phase bioreactor (BLL). Furthermore, the model allowed projecting under different biotic and abiotic conditions the BLL behavior. On the another hand, the BLL sequential operation during 20 cycles under oxygen limited conditions, improved the capability of the microbial consortium to biodegrade a Maya crude oil-paraffin mixture, leading to stable pattern of biodegradation from the fourth operation cycle of the bioreactor. The microbial consortium coming from the BLL, also was capable of biodegrade and mineralize without inhibition a total petroleum hydrocarbons mixture free of asphaltens. Power consumption and solid suspension studies in a sludge bioreactor (BLD) were carried out. The BLD was used to biodegrade the total petroleum hydrocarbons present in a weathered oilcontaminated soil. The studies showed that the flow descendent impeller with flat palettes and 45 degrees of inclination presented the better performance with respect to power consumption and effective solid suspension. Simultaneously studies of the oxygen convective transport in the BLD were carried out for soil loads until ten percent (w/v), being determined that the ranges in the impeller velocity (N, min-1) and air flow (Q, L min-1) that leading to the major values of the volumetric coefficient of oxygen transport (kLa h-1) were 425≤N≤445 and 5.25≤Q≤6.25
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
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
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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