227 research outputs found
A convergent reformulation of perturbative QCD
We present and explore a new formulation of perturbative QCD based not on the renormalised coupling but on the dimensional transmutation parameter of the theory and the property of asymptotic scaling. The approach yields a continued function, the iterated function being that involved in the solution of the two-loop β-function equation. In the so-called large-b limit the continued function reduces to a continued fraction and the successive approximants are diagonal Padé approximants. We investigate numerically the convergence of successive approximants using the leading-b approximation, motivated by renormalons, to model the all-orders result. We consider the Adler D-function of vacuum polarisation, the Polarised Bjorken and Gross-Llewellyn Smith sum rules, the (unpolarised) Bjorken sum rule, and the Minkowskian quantities R(_r) and the R-ratio of e(^+)e(^-) annihilation. In contrast to diagonal Fade approximants the truncated continued function method gives remarkably stable large-order approximants in cases where infra-red renormalon effects are important. We also use the new approach to determine the QCD fundamental parameters from the R(_r) and the R-ratio measurements, where we find Ā(^(3))(_MS)=516±48 MeV (which yields a(_s)(µ=m(_r))=0.360(^+0.021)(_=0.020)), and Ā(^(5))(_MS)=299(^+6)(_-7) MeV (which yields a(_s)(µ=m(_zo)=0.1218±0.0004), respectively. The evolution of the former value to the m(_zo) energy results in a(_s)(µ= m(_zo)) = 0.123 ± 0.002. These values are in line with other determinations available in the literature. We implement the Complete Renormalisation Group Improvement (CORGI) scheme throughout all the calculations. We report on how the mathematical concept of Stieltjes series can be used to assess the convergence of Padé approximants of perturbative series. We find that the combinations of UV renormalons which occur in perturbative QCD may or may not be Stieltjes series depending on the renormalisation scheme used
A Method to Identify and Analyze Biological Programs through Automated Reasoning.
Predictive biology is elusive because rigorous, data-constrained, mechanistic models of complex biological systems are difficult to derive and validate. Current approaches tend to construct and examine static interaction network models, which are descriptively rich but often lack explanatory and predictive power, or dynamic models that can be simulated to reproduce known behavior. However, in such approaches implicit assumptions are introduced as typically only one mechanism is considered, and exhaustively investigating all scenarios is impractical using simulation. To address these limitations, we present a methodology based on automated formal reasoning, which permits the synthesis and analysis of the complete set of logical models consistent with experimental observations. We test hypotheses against all candidate models, and remove the need for simulation by characterizing and simultaneously analyzing all mechanistic explanations of observed behavior. Our methodology transforms knowledge of complex biological processes from sets of possible interactions and experimental observations to precise, predictive biological programs governing cell function
Análisis de escenarios de Engorde a corral para vacas y novillitos en el sur de Mendoza
El presente trabajo es fruto de la adscripción del estudiante Rodrigo Novak a la Cátedra Economía Agraria de nuestra casa de estudios durante el año 2022, y consiste en el análisis económico de 3 modelos de producción para el mes de noviembre del año 2022, bajo los parámetros de un sistema ya existente en la finca “La Escandinava”, ubicada en el distrito de Bowen, departamento General Alvear, Mendoza. El análisis económico realizado es correspondiente a la metodología de las Normas de Gestión de AACREA, modificadas por la Cátedra de Economía Agraria, Facultad de Ciencias Veterinarias, UNLPam, y el análisis Marginal corresponde a un modelo solicitado por productores a la misma Cátedra en diversos encuentros presenciales. Se simplificó el análisis en 3 categorías: compra de novillitos de 220 kg y venta de novillitos livianos de 350 kg, destino mercado concentrador de Cañuelas; compra de novillitos de 290 kg y venta de novillos de 420 kg, destino mercado de Mendoza y compra de vacas conserva y venta de vacas manufactura, destino mercado concentrador de Cañuelas. Los modelos analizados arrojaron Márgenes Brutos por cabeza por ciclo de 29.646,70 y $ -30.647,95 respectivamente, resultados influenciados probablemente por el atraso en el precio del animal en pie con respecto al grano, y agravada esta situación por la distancia a los núcleos de producción maicera desde General Alvear. Se concluye que, en el contexto abordado, no es económicamente factible realizar ninguno de los negocios analizados
Effect of Constant Temperature on Development and Reproduction of the Cotton Aphid (Aphis gossypii) (Glover) (Hemiptera: Aphididae) on Gossypium hirsutum in Laboratory Conditions
Temperature-dependent development, survivorship and reproduction of the cotton aphid, Aphis gossypii on Gossypium hirsutum were evaluated at six constant temperatures (100, 150, 200, 250, 300 and 350C). The clean statistical breaks between developmental durations of all immature stages of aphids held at 100 and 150C indicate that at lower temperatures, all immature aphid stages (1st to 4th instars) are affected similarly by temperature changes. In viewing the survivorship curves (lx) for aphids held at the six constant temperatures, a general trend is evident. As temperature increased, survivorship progressively fell more precipitously, indicating increasing aphid mortality at a younger age. At 100, 150, 200, 250, 300 and 350C, aphid survivorship dropped below 80% at 39, 29, 33, 21, 20, and 14 days of life, respectively. Gross reproductive rate (GRR) an indicator of lifetime fecundity, ranged from 9.8 for aphids held at 100C to 58.9 for aphids held at 300C. A general rise in GRR was observed with rising temperature to 300C. The optimum temperature is closer to 250C. The results of this study agree with previous studies that the optimum aphid development temperature (held constant) in a laboratory study is 250 to 300C
Medios sociales y televisión: revisión bibliográfica a partir de la Web of Science
Una de las principales tendencias en la investigación actual sobre televisión se centra en el creciente papel de los medios sociales en el consumo televisivo. Este artículo revisa la bibliografía encontrada sobre medios sociales y televisión en la base de datos bibliográfica Web of Science desde 2005 a 2013. El objetivo es resaltar las cuestiones de investigación que están liderando el estudio tales como el debate sobre la definición de televisión social, el papel central de Twitter como principal herramienta social para la realización de actividades de “segunda pantalla”, los formatos de tele-realidad como los más comentados en las redes sociales, junto con otras formas de expresión del fenómeno fan. Las conclusiones de este artículo
reflexionan sobre posibles limitaciones de estos análysis y subraya nuevas líneas de investigación.One of the most important trends in current television research has to do with the increasing impact of social media on viewing and consumption. This article reviews the literature on social media and television included in the Web of Science database from 2005 to 2013 in order to find the main research questions guiding academic research within media studies.The topics investigated included the theoretical approach and definition of social television, the central role of Twitter as
the main social tool for second-screen activities, the prominence of “reality TV” as the most social genre on television, and new mainstream forms of television fandom. The conclusion of this article reflects on possible limitations of these studies and new paths of researc
The Effectiveness of Cognitive-Behavioral Stress Management and Grammatical Mental Imagery with Cognitive Processing on Negative Mood, Cognitive Regulation of Emotion and Quality of Life in Patients with Irritable Bowel Syndrome
Background: Irritable Bowel Syndrome (IBS) is a common gastrointestinal dysfunction with some psychological disorders. This study aimed to compare the effectiveness of cognitive-behavioral stress management (CBSM) and grammatical mental imagery with cognitive processing on reducing negative mood (depression and anxiety), cognitive regulation of emotion, and quality of life (QoL) in patients with IBS.
Methods: The study was a quasi-experimental one with pre-test and post-test and a control group. The statistical population included all male and female patients with IBS referred to Besat Gastroenterology Clinic in Tehran. The sample size of the present study was estimated to be 75 people who were randomly assigned to the CBSM group (n=25), the grammatical imaging experiment with cognitive processing (n=25), and the control group (n=25) by lottery method without replacement. The Cognitive Emotion Regulation Questionnaire (CERQ), Life Quality Questionnaire (SF-36), Beck's Depression Inventory, and The Spielberger State-Trait Anxiety Inventory (STAI) was used to collect data.
Results: The results of covariance analysis showed that CBSM therapy and grammatical mental imagery with cognitive processing were effective in reducing negative mood (depression and anxiety), cognitive regulation of emotion, and QoL (Pvalue=0.001). The results of covariance analysis also showed a significant difference between CBSM and grammatical mental imagery with cognitive processing only in terms of QoL. There was no significant difference between CBSM and grammatical mental imagery with cognitive processing in reducing negative mood (depression and anxiety), and cognitive emotion regulation.
Conclusions: According to the results, CBSM therapy and grammatical mental imagery with cognitive processing increase the QoL and reduce negative emotions in patients with IBS.
Keywords: Grammatical mental imagery, Cognitive-behavioral, Stress management, Quality of life, Irritable bowel syndrom
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