Renormalization of Scalar and Yukawa Field Theories with Lorentz Violation

We consider a theory of scalar and spinor fields, interacting through Yukawa and phi^4 interactions, with Lorentz-violating operators included in the Lagrangian. We compute the leading quantum corrections in this theory. The renormalizability of the theory is explicitly shown up to one-loop order. In the pure scalar sector, the calculations can be generalized to higher orders and to include finite terms, because the theory can be solved in terms of its Lorentz-invariant version.Comment: 30 page

Non-steady relaxation and critical exponents at the depinning transition

We study the non-steady relaxation of a driven one-dimensional elastic interface at the depinning transition by extensive numerical simulations concurrently implemented on graphics processing units (GPUs). We compute the time-dependent velocity and roughness as the interface relaxes from a flat initial configuration at the thermodynamic random-manifold critical force. Above a first, non-universal microscopic time-regime, we find a non-trivial long crossover towards the non-steady macroscopic critical regime. This "mesoscopic" time-regime is robust under changes of the microscopic disorder including its random-bond or random-field character, and can be fairly described as power-law corrections to the asymptotic scaling forms yielding the true critical exponents. In order to avoid fitting effective exponents with a systematic bias we implement a practical criterion of consistency and perform large-scale (L~2^{25}) simulations for the non-steady dynamics of the continuum displacement quenched Edwards Wilkinson equation, getting accurate and consistent depinning exponents for this class: \beta = 0.245 \pm 0.006, z = 1.433 \pm 0.007, \zeta=1.250 \pm 0.005 and \nu=1.333 \pm 0.007. Our study may explain numerical discrepancies (as large as 30% for the velocity exponent \beta) found in the literature. It might also be relevant for the analysis of experimental protocols with driven interfaces keeping a long-term memory of the initial condition.Comment: Published version (including erratum). Codes and Supplemental Material available at https://bitbucket.org/ezeferrero/qe

Radiatively Induced Lorentz and Gauge Symmetry Violation in Electrodynamics with Varying alpha

A time-varying fine structure constant alpha(t) could give rise to Lorentz- and CPT-violating changes to the vacuum polarization, which would affect photon propagation. Such changes to the effective action can violate gauge invariance, but they are otherwise permitted. However, in the minimal theory of varying alpha, no such terms are generated at lowest order. At second order, vacuum polarization can generate an instability--a Lorentz-violating analogue of a negative photon mass squared -m^2 proportional to alpha [(d alpha/dt) / alpha]^2 log (Lambda^2), where Lambda is the cutoff for the low-energy effective theory.Comment: 14 page

Systematic review and meta-analysis of the pharmacokinetics of benznidazole in the treatment of Chagas disease

Chagas disease is a neglected parasitic illness affecting approximately 8 million people, predominantly in Latin America. Benznidazole is the drug of choice for treatment, although its availability has been limited. A paucity of knowledge of the pharmacokinetic properties of this drug has contributed to its limited availability in several jurisdictions. The objective of this study was to conduct a systematic literature review and a Bayesian meta-analysis of pharmacokinetic studies to improve estimates of the basic pharmacokinetic properties of benznidazole. A systematic search of the Embase, Medline, LILACS, and SciELO (Scientific Electronic Library Online) databases was conducted. Eligible studies reported patient-level data from single-100-mg-dose pharmacokinetic evaluations of benznidazole in adults or otherwise provided data relevant to the estimation of pharmacokinetic parameters which could be derived from such studies. A Bayesian hierarchical model was used for analysis. Secondary data (i.e., data from studies that did not include patient-level, single-100-mg-dose data) were used for the generation of empirical priors for the Bayesian analysis. The systematic search identified nine studies for inclusion. Nine pharmacokinetic parameters were estimated, including the area under the concentration-time curve (AUC), the maximum concentration of drug in plasma (Cmax), the time to Cmax, the elimination rate constant (kel), the absorption rate constant (Ka), the absorption and elimination half-lives, the apparent oral clearance, and the apparent oral volume of distribution. The results showed consistency across studies. AUC and Cmax were 51.31 mg · h/liter (95% credible interval [CrI], 45.01, 60.28 mg · h/liter) and 2.19 mg/liter (95% CrI, 2.06, 2.33 mg/liter), respectively. Ka and kel were 1.16 h-1 (95% CrI, 0.59, 1.76 h-1) and 0.052 h-1 (95% CrI, 0.045, 0.059 h-1), respectively, with the corresponding absorption and elimination half-lives being 0.60 h (95% CrI, 0.38, 1.11 h) and 13.27 h (95% CrI, 11.79, 15.42 h), respectively. The oral clearance and volume of distribution were 2.04 liters/h (95% CrI, 1.77, 2.32 liters/h) and 39.19 liters (95% CrI, 36.58, 42.17 liters), respectively. A Bayesian meta-analysis was used to improve the estimates of the standard pharmacokinetic parameters of benznidazole. These data can inform clinicians and policy makers as access to this drug increases.Fil: Wiens, Matthew O.. University of British Columbia; CanadáFil: Kanters, Steve. Precision Global Health;Fil: Mills, Edward. Mc Master University; CanadáFil: Peregrina Lucano, Alejandro A.. Universidad de Guadalajara; MéxicoFil: Gold, Silvia. Fundación Mundo Sano; ArgentinaFil: Ayers, Dieter. Precision Global Health;Fil: Ferrero, Luis. Fundación Mundo Sano; ArgentinaFil: Krolewiecki, Alejandro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; Argentin

Competency-based Evaluation in Mechanical Physics

El Departamento de Física de la Universidad de los Andes está creando una propuesta pedagógica para facilitar la enseñanza y el aprendizaje de los cursos Física 1 y Física 2. Esta herramienta introducirá estrategias adicionales a los ya conocidos e implementados bancos de problemas, como: a) empleo de videos que mostrarán la solución de ejercicios clave por parte de algunos docentes de planta del mencionado Departamento; b) clasificación de ejercicios por objetivos, competencias y grados de dificultad, para que tanto estudiantes como docentes puedan enfocarse en áreas específicas que quieran profundizar, y c) visualización de experimentos demostrativos. La herramienta será de gran ayuda en el proceso evaluativo, ya que se pretende recopilar información estadística sobre la cantidad de ejercicios intentados, los que fueron respondidos de manera correcta o incorrecta, y los que fueron usados en períodos anteriores como parte de exámenes virtuales. Su implementación no solo obedece a la necesidad de crear espacios de aprendizaje autónomos para los estudiantes, aprovechar el uso de las TIC para innovar en los procesos de enseñanza y aprendizaje, y optimizar el uso de recursos y del tiempo, sino también para encontrar soluciones a los retos que conllevan situaciones de cuarentena que obligan a implementar métodos virtuales de enseñanza.Abstract: The Department of Physics at Universidad de Los Andes is currently creating a pedagogical tool in order to ease the teaching and learning processes in the courses of Physics 1 and Physics 2. This tool will introduce new strategies, in addition to the well-known and already implemented repositories of exercises, such as: a) the use of videos, in which some of the faculty members at the above mentioned institution will solve some key exercises, b) the classification of exercises by competences, objectives, and difficulty level, so allowing both professors and students to focus in the areas they want to delve into, and c) the visualization of demonstrative experiments. Additionally, this tool will be very helpful in the evaluation processes, as it will collect statistical information about the amount of exercises analyzed by the students, the accuracy in the responses that users provide, and real time information that indicates when the exercises were used in previous virtual exams. Not only does the implementation of this kind of strategies obey to the necessity of creating autonomous learning spaces for students, taking advantage of technology to innovate in the teaching and learning processes, optimizing time and resources, but also finding solutions to the challenges that arise from quarantine conditions that demand the use of virtual teaching methods

Magnetic domain wall creep and depinning: A scalar field model approach

Magnetic domain wall motion is at the heart of new magnetoelectronic technologies and hence the need for a deeper understanding of domain wall dynamics in magnetic systems. In this context, numerical simulations using simple models can capture the main ingredients responsible for the complex observed domain wall behavior. We present a scalar field model for the magnetization dynamics of quasi-two-dimensional systems with a perpendicular easy axis of magnetization which allows a direct comparison with typical experimental protocols, used in polar magneto-optical Kerr effect microscopy experiments. We show that the thermally activated creep and depinning regimes of domain wall motion can be reached and the effect of different quenched disorder implementations can be assessed with the model. In particular, we show that the depinning field increases with the mean grain size of a Voronoi tessellation model for the disorder.Fil: Caballero, Nirvana Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Ferrero, Ezequiel E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Kolton, Alejandro Benedykt. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Curiale, Carlos Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Jeudy, Vincent. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia. Université Paris–Saclay; FranciaFil: Bustingorry, Sebastián. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentin