Computational aspects of the through-focus characteristics of the human eye

Calculating through-focus characteristics of the human eye from a single objective measurement of wavefront aberration can be accomplished through a range of methods that are inherently computationally cumbersome. A simple yet accurate and computationally effcient method is developed, which combines the philosophy of the extended Nijboer-Zernike approach with the radial basis function based approximation of the complex pupil function. The main advantage of the proposed technique is that the increase of the computational cost for a vector valued defocus parameter is practically negligible in comparison to the corresponding scalar valued defocus parameter

The D-pi-property on products of pi-decomposable groups

[EN] The aim of this paper is to prove the following result: Let pi be a set of odd primes. If the group G = AB is the product of two p-decomposable subgroups A = A(pi) x A(pi') and B = B-pi x B-pi', then G has a unique conjugacy class of Hall pi-subgroups, and any p-subgroup is contained in a Hall pi-subgroup (i.e. G satisfies property D-pi)Research supported by Proyectos PROMETEO/2017/057 from the Generalitat Valenciana (Valencian Community, Spain), and PGC2018-096872-B-I00 from the Ministerio de Ciencia, Innovacion y Universidades, Spain, and FEDER, European Union; and second author also by Project VIP-008 of Yaroslavl P. Demidov State University.Kazarin, L.; Martínez-Pastor, A.; Pérez-Ramos, MD. (2020). The D-pi-property on products of pi-decomposable groups. Revista de la Real Academia de Ciencias Exactas Físicas y Naturales Serie A Matemáticas. 115(1):1-18. https://doi.org/10.1007/s13398-020-00950-z118115

On the product of two π-decomposable soluble groups

Let the group G = AB be a product of two π-decomposable sub-groups A = Oπ(A) × Oπ' (A) and B = Oπ(B) × Oπ' (B) where π is a set of primes. The authors conjecture that Oπ(A)Oπ(B) = Oπ(B)Oπ(A) if π is a set of odd primes. In this paper it is proved that the conjecture is true if A and B are soluble. A similar result with certain additional restrictions holds in the case 2 ∈ π. Moreover, it is shown that the conjecture holds if Oπ '(A) and Oπ'(B) have coprime orders

Finite trifactorized groups and pi-decomposability

The first author would like to thank the Universitat de Valencia for its warm hospitality and financial support during the preparation of this paper.Kazarin, LS.; Martínez-Pastor, A.; Perez Ramos, MD. (2018). Finite trifactorized groups and pi-decomposability. Bulletin of the Australian Mathematical Society. 97(2):218-228. https://doi.org/10.1017/S0004972717001034S21822897

Model selection for spectro-polarimetric inversions

Inferring magnetic and thermodynamic information from spectropolarimetric observations relies on the assumption of a parameterized model atmosphere whose parameters are tuned by comparison with observations. Often, the choice of the underlying atmospheric model is based on subjective reasons. In other cases, complex models are chosen based on objective reasons (for instance, the necessity to explain asymmetries in the Stokes profiles) but it is not clear what degree of complexity is needed. The lack of an objective way of comparing models has, sometimes, led to opposing views of the solar magnetism because the inferred physical scenarios are essentially different. We present the first quantitative model comparison based on the computation of the Bayesian evidence ratios for spectropolarimetric observations. Our results show that there is not a single model appropriate for all profiles simultaneously. Data with moderate signal-to-noise ratios favor models without gradients along the line-of-sight. If the observations shows clear circular and linear polarization signals above the noise level, models with gradients along the line are preferred. As a general rule, observations with large signal-to-noise ratios favor more complex models. We demonstrate that the evidence ratios correlate well with simple proxies. Therefore, we propose to calculate these proxies when carrying out standard least-squares inversions to allow for model comparison in the future.Comment: 16 pages, 2 figures, 8 tables, accepted for publication in Ap

Intermittent hypoxic training and cycling performance in triathletes

Los deportistas incorporan como complemento a su entrenamiento convencional, programas de entrenamiento en altitud para incrementar el rendimiento. El objetivo del estudio fue analizar los efectos sobre el umbral anaeróbico (Uan) producidos por un programa de entrenamiento en hipoxia intermitente (IHT) en triatletas. Participaron 18 triatletas divididos en un grupo de entrenamiento en hipoxia (GIHT: n=9; Edad: 26 ± 6.73 años; Talla 173.33 ± 5.94 cm; Peso: 66.38 ± 5.91 kg) y un grupo control (GC: n=9; Edad: 29.27 ± 6.84 años; Talla 174.89 ± 4.59 cm; Peso: 71.59 ± 6.81 Kg). Se aplicó un programa de IHT, complementario al entrenamiento habitual de 7 semanas al 15-14.5% de FiO2, 2 sesiones semanales de 60 minutos en cicloergómetro a la intensidad del Uan. Se llevó a cabo un test de umbrales lácticos previo y otro posterior al programa. El tratamiento propuesto produce un incremento en la potencia y el esfuerzo percibido en el Uan y disminuye la frecuencia cardiaca en el umbral aeróbico (Uae) y el UanAthletes include altitude training as a complement to their conventional training to improve performance. The aim of the study was to analyze the effects on anaerobic threshold (AT) produced by an IHT program in triathletes. 18 male trained triathletes were divided into intermittent hypoxic training group (GIHT: n=9; age: 26±6.73 years, height 173.33±5.94 cm, weight: 66.38±5.91 kg) and control group (GC: n=9; age: 29.27±6.84 years, height 174.89±4.59 cm, weight: 71.59±6.81 kg). The IHT program consisted of two 60-min sessions per week at intensities over the AT and atmospheric conditions between 14.5 and 15% FiO2. Before and after the program, cycling performance in a lactate thresholds test was determined. The treatment caused an improvement in the power output and perceived exertion in AT and enhanced cardiac performance in the aerobic threshold and AT