130,582 research outputs found
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
Simple decision rule for risk stratification of elderly with acute type B aortic dissection
No full textScholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
Modeling of a trickling filter reactor for the hydrolysis of corncob leaf
No full textgraficas, ilustraciones, tablasEl desarrollo de nuevos procesos es un tema de gran interés para la ingeniería de reactores, ya que se hace necesario mejorar e implementar nuevas prácticas en la industria que garanticen un futuro sostenible mediante la transformación de diferentes materiales. En general, la aplicabilidad de estos procesos a escala comercial está limitada por la complejidad de las reacciones en serie que se dan y las tecnologías de baja eficiencia, lo que conduce a que sean económicamente inviables. Por lo tanto, es necesario un profundo conocimiento del proceso y su operatividad para proponer tecnologías innovadoras que contribuyan a superar las restricciones mencionadas, mejorando así la incorporación de nuevos procesos para la transformación de materiales lignocelulósicos. En esta disertación, se desarrolló un nuevo concepto de reactor percolador para la producción y extracción de azúcares como: xilosa, glucosa, manosa, arabinosa y galactosa o subproductos como el furfural. Este proceso se desarrolló utilizando desechos biodegradables como la hoja de mazorca debido a que un material económico y de alta disponibilidad en Colombia.
El análisis del reactor se realizó en tres etapas: el modelamiento del reactor percolador mediante el software de Matlab® y la integración de este modelamiento con sección experimental para obtener los parámetros cinéticos que modelan la hidrólisis de la hemicelulosa y finalmente optimización de las concentraciones de los azúcares.
En la etapa del modelamiento del reactor percolador, se obtuvieron las ecuaciones del balance de masa que predecían las concentraciones de los productos y subproductos de la descomposición de la hemicelulosa de la hoja de mazorca. Para la obtención del modelamiento se realizó una caracterización del material lignocelulósico, obteniendo así los porcentajes de hemicelulosa, celulosa y lignina presentes en la materia para ser adaptados al modelo. El modelamiento del reactor percolador se desarrolló mediante el software Matlab®, utilizando una subrutina de optimización global y el comando fmincon para minimizar la función objetivo que consistía en minimizar la sumatoria de los residuales al cuadrado.
Una vez obtenido el modelamiento, éste se ajustó con los resultados de los datos experimentales de la hidrólisis de la hoja de mazorca. El ajuste del modelo del reactor percolador se realizó mediante un diseño secuencial obteniéndose la estimación de parámetros cinéticos, para esto primero se seleccionó las condiciones iniciales experimentales, luego se ajustaron los parámetros, seguidamente se utilizó el modelo secuencial para la predicción de nuevas condiciones de operación. Se hizo necesario la verificación de la calidad de la predicción del modelo (varianza de los parámetros del modelo), donde la varianza se ajustó a un valor máximo del 6%, para termina el proceso de ajuste.
Finalmente, con los parámetros cinéticos ajustados, se optimizaron las ecuaciones de los balances que mostraban el comportamiento de la producción de azúcares para obtener concentraciones máximas de xilosa y furfural, por medio de nuevas rutinas de software Matlab®, con el comando fmincon. La productividad del sistema fue más alta que la obtenida en otros reactores para hidrólisis de este tipo de materiales. El desempeño obtenido con estos reactores muestra el potencial de la tecnología desarrollada y es la fuerza impulsora para continuar investigando la optimización de los procesos. (Texto tomado de la fuente)The development of new processes is a topic of great interest for reactor engineering, since it is necessary to improve and implement new practices in the industry that guarantee a sustainable future through the transformation of different materials. The applicability of these processes on a commercial scale is limited by the complexity of the series reactions involved and the low efficiency technologies, which leads to their economic unfeasibility. Therefore, a deep knowledge of the process and its operability is necessary to propose innovative technologies that contribute to overcome the mentioned restrictions, thus improving the incorporation of new processes for the transformation of lignocellulosic materials. In this dissertation, a new concept of percolator reactor was developed for the production and extraction of sugars such as xylose, glucose, mannose, arabinose and galactose or by-products such as furfural. This process was developed using biodegradable wastes such as corncob leaves because it is an inexpensive and highly available material in Colombia.
The reactor analysis was carried out in three stages: modeling of the percolator reactor using Matlab® software and integration of this modeling with experiments to get the kinetic parameters that model the hydrolysis of hemicellulose and finally optimization of the product concentrations.
In the modeling stage of the percolator reactor, mass balance equations were derived to predict the concentrations of the products and by-products from the decomposition of the hemicellulose of the corncob leaf. For the simulation model, a characterization of the lignocellulosic material was performed to measure the percentages of hemicellulose, cellulose, and lignin present in the material to be included in the model. The modeling of the percolator reactor was developed using Matlab® software, using a global optimization subroutine and the fmincon command to minimize the objective function that consisted of minimizing the sum of the squared residuals.
The simulation model was adjusted with the results of the experimental data of the hydrolysis of the cob leaf. The parameters were fitted by a sequential design of experiments, first the initial experimental conditions were selected, then the parameters were adjusted, then the sequential model was used for the prediction of new operating conditions for the next experimental. It was necessary to verify the quality of the model prediction (variance in the model parameters). The variance was adjusted to a value of 5%.
Finally, with the model of the percolator reactor, the operating conditions were optimized to attain maximum concentrations of xylose and furfural. The productivity of the percolator reactor is higher than the one reached by other reactors for hydrolysis of this type of materials. The performance of a percolator reactor is superior to the conventional batch and plug flow reactors.MaestríaMagíster en Ingeniería - Ingeniería QuímicaQuímica Y Procesos.Sede Manizale
The R&D Tax Incentives
No full textThis article sets out some background information and reflections of the author on the R&D tax incentive schemes included in the Common Corporate Tax Base (CCTB) Proposal. In particular the author analyzes the stimulus to private R&D through ad hoc tax incentives included in the CCTB Proposal and dives into the actual provisions included in the Proposal highlighting the most relevant issues connected with their design and interpretation. Moreover, the author explores the interaction between the CCTB Proposal and the granting by Member States of domestic R&D tax incentives
Acute Aortic Dissection in the elderly: Clinical characteristics, management, and outcomes in the current era
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