Football goal distributions and extremal statistics

We analyse the distributions of the number of goals scored by home teams, away teams, and the total scored in the match, in domestic football games from 169 countries between 1999 and 2001. The probability density functions (PDFs) of goals scored are too heavy-tailed to be fitted over their entire ranges by Poisson or negative binomial distributions which would be expected for uncorrelated processes. Log-normal distributions cannot include zero scores and here we find that the PDFs are consistent with those arising from extremal statistics. In addition, we show that it is sufficient to model English top division and FA Cup matches in the seasons of 1970/71–2000/01 on Poisson or negative binomial distributions, as reported in analyses of earlier seasons, and that these are not consistent with extremal statistics

Approaching a fully-polarized state of nuclear spins in a solid

Magnetic noise of atomic nuclear spins is a major source of decoherence in solid-state spin qubits. In theory, near-unity nuclear spin polarization can eliminate decoherence of the electron spin qubit, while turning the nuclei into a useful quantum information resource. However, achieving sufficiently high nuclear polarizations has remained an evasive goal. Here we implement a nuclear spin polarization protocol which combines strong optical pumping and fast electron tunneling. Nuclear polarizations well above 95% are generated in GaAs semiconductor quantum dots on a timescale of 1 minute. The technique is compatible with standard quantum dot device designs, where highly-polarized nuclear spins can simplify implementations of qubits and quantum memories, as well as offer a testbed for studies of many-body quantum dynamics and magnetism

Dynamics of tournaments: the soccer case

A random walk-like model is considered to discuss statistical aspects of tournaments. The model is applied to soccer leagues with emphasis on the scores. This competitive system was computationally simulated and the results are compared with empirical data from the English, the German and the Spanish leagues and showed a good agreement with them. The present approach enabled us to characterize a diffusion where the scores are not normally distributed, having a short and asymmetric tail extending towards more positive values. We argue that this non-Gaussian behavior is related with the difference between the teams and with the asymmetry of the scores system. In addition, we compared two tournament systems: the all-play-all and the elimination tournaments.Comment: To appear in EPJ

Generalised joint regression for count data: a penalty extension for competitive settings

We propose a versatile joint regression framework for count responses. The method is implemented in the R add-on package GJRM and allows for modelling linear and non-linear dependence through the use of several copulae. Moreover, the parameters of the marginal distributions of the count responses and of the copula can be specified as flexible functions of covariates. Motivated by competitive settings, we also discuss an extension which forces the regression coefficients of the marginal (linear) predictors to be equal via a suitable penalisation. Model fitting is based on a trust region algorithm which estimates simultaneously all the parameters of the joint models. We investigate the proposal’s empirical performance in two simulation studies, the first one designed for arbitrary count data, the other one reflecting competitive settings. Finally, the method is applied to football data, showing its benefits compared to the standard approach with regard to predictive performance

The Type Locality Of Sciapus pressipes Parent (Diptera, Dolichopodidae)

Volume: 92Start Page: 584End Page: 58

Facebook disclosure and well-being

"The social networking site Facebook has become a popular worldwide communication application on the Internet and has quickly become one of the most widely used websites in the world. Due to the fact this website is now regularly used by 700 million people throughout the world, it is imperative that we understand the implications of its use. Much research has been conducted to investigate the Internet and how it relates to well-being. However, literature distinctly designed to investigate Facebook is lacking. The current research addresses this gap in the literature by investigating Facebook and its correlation to well-being. In particular it examines intensity and disclosure on Facebook and how it relates to psychological well-being (PWB) and perceived social support from one‟s Facebook friends (FBPSS). Researchers have found evidence that supports the benefits of disclosure on one‟s psychological well-being. Disclosing face to face to others has been established to strengthen relationships and promote emotional healing (Collins & Miller, 1994; Faber, 2006). The aim of this study is to investigate whether or not disclosing on the social networking site Facebook to one‟s Facebook friends has similar benefits. The relationship between disclosing and using Facebook and perceived social support was also examined. An online survey was conducted by 75 Facebook users and found evidence to support that Facebook use does not improve one‟s psychological and well-being, however disclosing and using Facebook intensely does improve one‟s perceived social support."--Abstract