tbW vertex in the Littlest Higgs Model with T-parity

A study of the effective tbW vertex is done in the littlest Higgs model with T parity that includes the one loop induced weak dipole coefficient f_{2R}. The top's width, the W-boson helicity in the t-> bW^+ decay as well as the t-channel and the s-channel modes of single top quark production at the LHC are then obtained for the tbW coupling. Our calculation is done in the Feynman-'t Hooft gauge, and we provide details of the analysis, like exact formulas (to all orders of the expansion variable v/f) of masses and mixing angles of all the particles involved. Also, a complete and exact diagonalization (and normalization) of the scalar sector of the model is made.Comment: Version published in Phys. Rev. D79, 015013 (2009

Synthesis of Spherical 4R Mechanism for Path Generation using Differential Evolution

The problem of path generation for the spherical 4R mechanism is solved using the Differential Evolution algorithm (DE). Formulas for the spherical geodesics are employed in order to obtain the parametric equation for the generated trajectory. Direct optimization of the objective function gives the solution to the path generation task without prescribed timing. Therefore, there is no need to separate this task into two stages to make the optimization. Moreover, the order defect problem can be solved without difficulty by means of manipulations of the individuals in the DE algorithm. Two examples of optimum synthesis showing the simplicity and effectiveness of this approach are included.Comment: Submitted to Mechanism and Machine Theor

Top-pions and single top production at HERA and THERA

We study single top quark production at the HERA and THERA colliders as coming from the FCNC vertices tcgamma and tcZ that appear at one loop level in Topcolor-assisted technicolor models (TC2). In contrast with previous expectations, we find that the production cross section is of order 10^-6 pb for HERA and 10^-4 pb for THERA (even lower that the SM prediction). Therefore, none of the two colliders are capable to probe the pseudoscalar top-pion or the scalar top-higgs predicted in TC2 models via single top production.Comment: 5 pages, 2 figures. Paragraph and 1 reference adde

Fractal dimension measured over areas and perimeters using “Box Counting” technique applied over a Mandelbrot figure.

Measuring fractal dimension in general is made over edges of a figure, however this kind of calculations could be made over a 1D, 2D or even a 3D images. With the FracLac plugin of ImageJ application, it has been possible to measure both dimensions, over the area and over the edge of a Mandelbrot fractal, using the Box Counting technique

Closed-Form Solutions to Differential Equations via Differential Evolution

We focus on solving ordinary differential equations using the evolutionary algorithm known as differential evolution (DE). The main purpose is to obtain a closed-form solution to differential equations. To solve the problem at hand, three steps are proposed. First, the problem is stated as an optimization problem where the independent variables are elementary functions. Second, as the domain of DE is real numbers, we propose a grammar that assigns numbers to functions. Third, to avoid truncation and subtractive cancellation errors, to increase the efficiency of the calculation of derivatives, the dual numbers are used to obtain derivatives of functions. Some examples validating the effectiveness and efficiency of our method are presented

A comparison between “rod counting” and “box counting” methods in linear fractal dimensions measurements

In this work, the “rod counting” method is reviewed in comparison with the “box counting” method applied to linear measurements on irregular figures. Both methods are applied in measurements of fractal dimension of some knowing fractals. Results shows that the “rod counting” method is more accurate in linear measurements. Later the method is applied in a Mandelbrot fractal figure to measure its perimeter fractal dimension

Causes of revisional surgery, reoperations, and readmissions after bariatric surgery

Introduction and objectives: Bariatric surgery is the most effective treatment for weight loss, with comorbidity control. With low complication rates, the reasons for reoperation are major complications or weight loss failure/weight regain. Nonsurgical problems can also present, such as anemia, dehydration, chronic pain, and malnutrition, among others. Our aim was to analyze the main causes of revisional surgery, reoperation, and hospital readmission, at a specialized bariatric center. Methods: A retrospective study was conducted on patients that underwent bariatric surgery within the time frame of 2012 and 2019. The baseline analysis included demographic, anthropometric, and perioperative data, as well as a sub-analysis of the main readmission causes and complications. Results: A total of 776 primary surgeries were performed (649 RYGBP, 127 SG, and 10 revisional surgeries), and 99 patients were identified for the study: 10 revisional surgeries, 44 reoperations, and 45 readmissions. The incidence of revisional surgery was 1.2%, reoperation was 5.6%, and readmission 5.8%. Fifty percent of the revisional surgeries were performed due to insufficient weight loss or weight regain; the most frequent causes of reoperation were cholecystitis (38.6%) and internal hernias (9.1%); and the most common causes of readmission were nonspecific abdominal pain (35.5%) and dehydration (24.4%). Conclusion: The most frequent causes of postoperative readmission were nonsurgical events, followed by non-bariatric reoperations, and finally revisional surgeries. There was a low incidence of early reoperations. Knowledge of the abovementioned data is important for identifying higher-risk patients, to prevent major complications. Resumen: Introducción y objetivos: La cirugía bariátrica es el tratamiento más efectivo para la pérdida de peso, con control de comorbilidades. Con bajas tasas de complicaciones, las razones para una reintervención pueden ser complicaciones mayores o falla/reganancia de peso. También se presentan problemas no quirúrgicos como anemia, deshidratación, dolor crónico y desnutrición, entre otros. El objetivo fue analizar las principales causas de cirugía revisional, reoperación y readmisión en un centro bariátrico de referencia. Métodos: Estudio retrospectivo de pacientes sometidos a cirugía bariátrica entre 2012 y 2019. Se realizó un análisis basal incluyendo datos demográficos, antropométricos y perioperatorios y un subanálisis con las principales indicaciones de readmisión y complicaciones. Resultados: Se realizaron 776 cirugías primarias (649 BPGYR, 127 MG y 10 cirugías de revisión), incluyendo 99 pacientes para el estudio: 10 de cirugía revisional, 44 reoperaciones y 45 readmisiones. La incidencia de cirugía revisional fue 1,2%, reoperación y readmisión 5,6% y 5,8% respectivamente. El 50% de las cirugías revisionales fue por pérdida insuficiente o reganancia de peso. Las causas más frecuentes de reoperación fueron: colecistitis (38.6%) y hernias internas (9.1%); las causas de readmisión más comunes fueron dolor abdominal inespecífico (35.5%) y deshidratación (24.4%). Conclusión: Las causas más frecuentes de readmisión poscirugía fueron enfermedades no quirúrgicas, seguido de reoperaciones no bariátricas y, finalmente, cirugías de revisión. Las reoperaciones tempranas por complicaciones tienen una incidencia baja. Es importante conocer lo previo para identificar a los pacientes con mayor riesgo y así prevenir complicaciones mayores

Causas de cirugía revisional, reoperaciones y readmisión posterior a cirugía bariátrica

Resumen: Introducción y objetivos: La cirugía bariátrica es el tratamiento más efectivo para la pérdida de peso, con control de comorbilidades. Con bajas tasas de complicaciones, las razones para una reintervención pueden ser complicaciones mayores o falla/reganancia de peso. También se presentan problemas no quirúrgicos como anemia, deshidratación, dolor crónico y desnutrición, entre otros. El objetivo fue analizar las principales causas de cirugía revisional, reoperación y readmisión en un centro bariátrico de referencia. Métodos: Estudio retrospectivo de pacientes sometidos a cirugía bariátrica entre 2012 y 2019. Se realizó un análisis basal incluyendo datos demográficos, antropométricos y perioperatorios y un subanálisis con las principales indicaciones de readmisión y complicaciones. Resultados: Se realizaron 776 cirugías primarias (649 BPGYR, 127 MG y 10 cirugías de revisión), incluyendo 99 pacientes para el estudio: 10 de cirugía revisional, 44 reoperaciones y 45 readmisiones. La incidencia de cirugía revisional fue 1,2%, reoperación y readmisión 5,6% y 5,8% respectivamente. El 50% de las cirugías revisionales fue por pérdida insuficiente o reganancia de peso. Las causas más frecuentes de reoperación fueron: colecistitis (38.6%) y hernias internas (9.1%); las causas de readmisión más comunes fueron dolor abdominal inespecífico (35.5%) y deshidratación (24.4%). Conclusión: Las causas más frecuentes de readmisión poscirugía fueron enfermedades no quirúrgicas, seguido de reoperaciones no bariátricas y, finalmente, cirugías de revisión. Las reoperaciones tempranas por complicaciones tienen una incidencia baja. Es importante conocer lo previo para identificar a los pacientes con mayor riesgo y así prevenir complicaciones mayores. Abstract: Introduction and objectives: Bariatric surgery is the most effective treatment for weight loss, with comorbidity control. With low complication rates, the reasons for reoperation are major complications or weight loss failure/weight regain. Nonsurgical problems can also present, such as anemia, dehydration, chronic pain, and malnutrition, among others. Our aim was to analyze the main causes of revisional surgery, reoperation, and hospital readmission, at a specialized bariatric center. Methods: A retrospective study was conducted on patients that underwent bariatric surgery within the time frame of 2012 and 2019. The baseline analysis included demographic, anthropometric, and perioperative data, as well as a sub-analysis of the main readmission causes and complications. Results: A total of 776 primary surgeries were performed (649 RYGBP, 127 SG, and 10 revisional surgeries), and 99 patients were identified for the study: 10 revisional surgeries, 44 reoperations, and 45 readmissions. The incidence of revisional surgery was 1.2%, reoperation was 5.6%, and readmission 5.8%. Fifty percent of the revisional surgeries were performed due to insufficient weight loss or weight regain; the most frequent causes of reoperation were cholecystitis (38.6%) and internal hernias (9.1%); and the most common causes of readmission were nonspecific abdominal pain (35.5%) and dehydration (24.4%). Conclusion: The most frequent causes of postoperative readmission were nonsurgical events, followed by non-bariatric reoperations, and finally revisional surgeries. There was a low incidence of early reoperations. Knowledge of the abovementioned data is important for identifying higher-risk patients, to prevent major complications

Annual distribution of the Sun’s angular positions, study at 21 degrees of latitude

It is well know that the Sun position, measured over the heart surface is a function of the latitude and the hour of a particular day. Usually, the Sun follows a different path from one day to the next, and this is determined by the azimuth and zenith angles. The analytical calculations for determining the angular position at any time (solar hour) are an overwhelming task. We use the Mathematica® software to write a home code for determining at any time (in intervals of one minute) and latitude, the azimuth and zenith angles of the Sun for every day of the year. In order to show general results of interest, in this work we present the annual distribution of the angular positions and the length of the day (hours of light) for the 21 degrees of latitude. This information could be used for optimizing the orientation of solar panels and collectors and for the design of cheap houses where the walls can be exposed to the minimal solar incidence