The quantum Arnold transformation

By a quantum version of the Arnold transformation of classical mechanics, all quantum dynamical systems whose classical equations of motion are non-homogeneous linear second-order ordinary differential equations, including systems with friction linear in velocity, can be related to the quantum free-particle dynamical system. This transformation provides a basic (Heisenberg-Weyl) algebra of quantum operators, along with well-defined Hermitian operators which can be chosen as evolution-like observables and complete the entire Schr\"odinger algebra. It also proves to be very helpful in performing certain computations quickly, to obtain, for example, wave functions and closed analytic expressions for time-evolution operators.Comment: 19 pages, minor changes, references update

Effects of supplementation of L-carnitine on the body composition of trained and sedentary rats

El objetivo del presente estudio es determinar el efecto de la suplementación de L-carnitina sobre la composición corporal de ratas entrenadas y sedentarias. Fueron seleccionadas de forma aleatoria 30 ratas machos Wistar, de 12 semanas de vida, cuyo peso osciló entre 350 a 380 gramos, constituyéndose cuatro grupos de animales: sedentario no suplementado (SNS), sedentario suplementado (SS), entrenado no suplementado (ENS) y entrenado suplementado (ES). El entrenamiento fue realizado con sesiones de carrera en la estera rodante, con duración de una hora y con suplementación oral crónica de L-Carnitina. Ambos protocolos con una duración de 4 semanas. La composición corporal fue evaluada a través de ecuaciones de predicción para determinar la masa libre de grasa (MLG) y masa de grasa (MG). Los resultados muestran que el entrenamiento físico disminuye los valores de la MLG y MG en el grupo ENS, y que la administración de la L-carnitina en forma conjunta con el entrenamiento físico revierte parcialmente la reducción de la MLG en el grupo ES. Finalmente se concluye que el ejercicio físico debe ser realizado juntamente con la suplementación de L-carnitina, permitiendo una disminución de la MG y mantener los niveles de MLG en ratas en proceso de crecimiento.The aim of this study is to determine the effect of L-carnitine supplementation on body composition of trained and sedentary rats. Were randomly selected 30 male Wistar rats of 12 weeks of age, whose weight ranged between 350 to 380 grams, four groups of animals: sedentary non-supplemented (SNS), sedentary supplemented (SS), trained not supplemented (ENS) trained and supplemented (ES). The training was done with sessions running on a treadmill, lasting an hour and chronic oral supplementation of L-carnitine. Both protocols with a duration of 4 weeks. Body composition was assessed by prediction equations to determine fat-free (FFM) and fat mass (FM). The results show that physical training decreases the values of FFM and FM in the ENS group, and that the administration of L-carnitine together with physical training partially reverses the reduction of MLG in ES. Finally concluded that physical exercise should be conducted jointly with the supplementation of L-carnitine, allowing a reduction in the MG and maintain levels in rats MLG growth process.Peer Reviewe

A simple and efficient statistical potential for scoring ensembles of protein structures

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Perioperative management in thoracic surgery.

Thoracic surgery has undergone significant advances in recent years related to anesthetic and surgical techniques and the prevention and management of complications related to the procedure. This has allowed improvements in patient clinical outcomes in surgeries of this kind. Despite the above, thoracic surgery, especially related to pulmonary resection, is not without risk, and is associated to considerable morbidity and mortality. Fast track or enhanced recovery after anesthesia protocols, minimally invasive surgery, and intraoperative anesthetic management improve the prognosis and safety of thoracic surgery. Patients in the postoperative period of major thoracic surgery require intensive surveillance, especially the first 24–72h after surgery. Admission to the ICU is especially recommended in those patients with comorbidities, a reduced cardiopulmonary reserve, extensive lung resections, and those requiring support due to life-threatening organ failure. During the postoperative period, intensive cardiorespiratory monitoring, proper management of thoracic drainage, aggressive pain control (multimodal analgesia and regional anesthetic techniques), nausea and multimodal rehabilitation are key elements for avoiding adverse events. Medical complications include respiratory failure, arrhythmias, respiratory infections, atelectasis and thromboembolic lung disease. The most frequent surgical complications are hemothorax, chylothorax, bronchopleural fistula and prolonged air leakage. The multidisciplinary management of these patients throughout the perioperative period is essential in order to ensure the best surgical outcomes.post-print512 K

Gobernabilidad en Santa Cruz de la Sierra: Pautas para mayor transparencia y democracia local

A partir de los años ochenta se inició una nueva etapa democrática en Bolivia, después de quince años de alternar entre gobiernos dictatoriales y constitucionales. La profundización de la democracia fue prolongada (1978-1982), costosa, lenta y complicada. El desarrollo de las democracias locales, como parte del proceso general, constituyó un paso importante en esta consolidación y estuvo marcada por la aprobación de leyes que promueven la descentralización y la participación popular, tendientes a fortalecer la institucionalidad pública y a mejorar la calidad de vida de los ciudadanos, con una distribución más equitativa de los recursos financieros administrados bajo el régimen de vigilancia y control social. El proceso estuvo matizado por problemas de legitimidad y gobernabilidad. Una vez superados los unos se presentaron otros, generando un debate permanente y cambiante sobre el tema