The Impact of Participation in Sports on Educational Attainment: New Evidence from Germany

We analyze the impact of exercising sports during childhood and adolescence on educational attainment. The theoretical framework is based on models of allocation of time and educational productivity. Using the rich information from the German Socio-Economic Panel (GSOEP), we apply generalized ordered probit models to estimate the effect of participation in sport activities on secondary school degrees and professional degrees. Even after controlling for important variables and selection into sport, we find strong evidence that the effect of sport on educational attainment is statistically significant and positive.allocation of time, education, human capital, sport

Computing Preferred Answer Sets by Meta-Interpretation in Answer Set Programming

Most recently, Answer Set Programming (ASP) is attracting interest as a new paradigm for problem solving. An important aspect which needs to be supported is the handling of preferences between rules, for which several approaches have been presented. In this paper, we consider the problem of implementing preference handling approaches by means of meta-interpreters in Answer Set Programming. In particular, we consider the preferred answer set approaches by Brewka and Eiter, by Delgrande, Schaub and Tompits, and by Wang, Zhou and Lin. We present suitable meta-interpreters for these semantics using DLV, which is an efficient engine for ASP. Moreover, we also present a meta-interpreter for the weakly preferred answer set approach by Brewka and Eiter, which uses the weak constraint feature of DLV as a tool for expressing and solving an underlying optimization problem. We also consider advanced meta-interpreters, which make use of graph-based characterizations and often allow for more efficient computations. Our approach shows the suitability of ASP in general and of DLV in particular for fast prototyping. This can be fruitfully exploited for experimenting with new languages and knowledge-representation formalisms.Comment: 34 pages, appeared as a Technical Report at KBS of the Vienna University of Technology, see http://www.kr.tuwien.ac.at/research/reports

Повышение эффективности сжигания композиционного жидкого топлива на тепловых электрических станциях по условиям его зажигания

Высокие показатели загрязнения окружающей среды котельными и тепловыми электрическими станциями, сжигающими угли разных марок, являются основной причиной активных исследований в мире, направленных на разработку альтернативных топлив. Приемлемое по экологическим, энергетическим и технико-экономическим критериям решение сформулированной проблемы – создание композиционных жидких топлив с применением измельченного угля или отходов углеобогащения, воды и отработанных нефтепродуктов. Для адекватного изучения процессов зажигания разработана модельная камера сгорания. С ее использованием определены типичные режимы зажигания суспензионных топлив. Показаны принципиальные отличия условий зажигания витающих одиночных капель, группы капель, а также полидисперсного потока композиционных жидких топлив.High rates of environmental pollution by domestic heaters and boiler (as well as thermal power plants) that burn different types of a coal are the main reason of an active research aimed to development of the alternative fuels. The desired solution should satisfy the environmental, energetic, technical and economic criteria defining the overall usability of the fuel. The proposed way is preparation of the liquid fuel composition using the crushed coal or coal enrichment waste, water and waste oil products. The model combustion chamber was developed to study the ignition processes. The typical ignition modes of suspension fuels were determined using this chamber. The principal differences of the regimes of ignition of single droplets, group of droplets, as well as a whole polydisperse drop

Sub-Cycle Strong-Field Interferometry

A nonlinear interferometry scheme is described theoretically to induce and resolve electron wave- function beating on time scales shorter than the optical cycle of the time-delayed pump and probe pulses. By employing two moderately intense few-cycle laser fields with a stable carrier-envelope phase, a large range of the entire electronic level structure of a quantum system can be retrieved. In contrast to single-photon excitation schemes, the retrieved electronic states include levels that are both dipole- and non-dipole-accessible from the ground electronic state. The results show that strong-field interferometry can reveal both high-resolution and broad-band spectral information at the same time with important consequences for quantum-beat spectroscopy on attosecond or even shorter time scales.Comment: first submitted on April 19, 201

Broadband high-resolution x-ray frequency combs

Optical frequency combs have had a remarkable impact on precision spectroscopy. Enabling this technology in the x-ray domain is expected to result in wide-ranging applications, such as stringent tests of astrophysical models and quantum electrodynamics, a more sensitive search for the variability of fundamental constants, and precision studies of nuclear structure. Ultraprecise x-ray atomic clocks may also be envisaged. In this work, an x-ray pulse-shaping method is put forward to generate a comb in the absorption spectrum of an ultrashort high-frequency pulse. The method employs an optical-frequency-comb laser, manipulating the system's dipole response to imprint a comb on an excited transition with a high photon energy. The described scheme provides higher comb frequencies and requires lower optical-comb peak intensities than currently explored methods, preserves the overall width of the optical comb, and may be implemented by presently available x-ray technology