Predicting probabilities for the 2010 FIFA World Cup games using a Poisson-Gamma model

In this paper, we provide probabilistic predictions for soccer games of the 2010 FIFA World Cup modelling the number of goals scored in a game by each team. We use a Poisson distribution for the number of goals for each team in a game, where the scoring rate is considered unknown. We use a Gamma distribution for the scoring rate and the Gamma parameters are chosen using historical data and difference among teams defined by a strength factor for each team. The strength factor is a measure of discrimination among the national teams obtained from their memberships to fuzzy clusters. The clusters are obtained with the use of the Fuzzy C-means algorithm applied to a vector of variables, most of them available on the official FIFA website. Static and dynamic models were used to predict the World Cup outcomes and the performance of our predictions was evaluated using two comparison methods.     

Greenspace sites conserve taxonomic and functional diversity of dung beetles in an urbanized landscape in the Brazilian Cerrado

Urban Ecosystems - Urbanization transforms natural ecosystems, creating an environmental mosaic, characterized by native vegetation sites mixed with constructed sites. In this study, we compared...     

Intrinsic and extrinsic drivers of yard vegetation in urban residential areas: implications for conservation planning

Residential green areas often represent a significant portion of a city’s green infrastructure which has generated great interest in studying the factors that contribute to the formation of plant associations in residential yards. This project evaluated the external factors to the household social-ecological system that influence the availability of plants for residential landscapes and how they may influence the presence of native plants in residential yards on households within the Río Piedras watershed in the metropolitan area of San Juan, Puerto Rico. The methods used included a residential survey with open and closed questions that addressed the sources of plants used in landscaping and an evaluation of ornamental plant species inventories from local nurseries. A total of 432 yards were surveyed. Yard plants in this watershed have multiple sources. Aside from obtaining plants at local nurseries, natural dispersion, exchanges among family and friends and historical plantings can be just as important sources of yard plants. Our results also suggest that the majority of residents do not know where to get native plants which could represent a challenge for the development and implementation of initiatives for natives gardening. At the same time, most commercial nurseries have a deficit of native plants in their inventories. This information is critical to species conservation strategies that seek the inclusion of urban residential areas and may help improve initiatives about the involvement of individual citizens in sustainable gardening practices at the residential scale.     

Digital skills and social media use: how Internet skills are related to different types of Facebook use among ‘digital natives’

Based on the idea that Internet use can be conceptualized in terms of depth (frequency) and width (differentiated) uses of the Web, this study explored how socio-demographic factors and digital skills are related to frequency and types of Facebook use among young adults. It used a face-to-face representative survey conducted in the three main urban areas of Chile among a sample of 18-to 29-year olds. The results found that men and more educated young people had higher levels of skills, confirming that the so-called ‘digital natives’ are not a monolithic group. They also revealed that digital skills did not predict frequency of Facebook use. Furthermore, lower educated young people tended to use Facebook more frequently. Although these results go against the long-established digital divide research, traditional digital gaps emerged when types of use were analyzed. While more educated and skillful individuals tended to use Facebook for informational and mobilizing purposes, socio-demographic factors and skills did not make a difference in Facebook use for social purposes.     

Non-parametric Quantile Regression with Censored Data

Abstract.  Censored regression models have received a great deal of attention in both the theoretical and applied statistics literature. Here, we consider a model in which the response variable is censored but not the covariates. We propose a new estimator of the conditional quantiles based on the local linear method, and give an algorithm for its numerical implementation. We study its asymptotic properties and evaluate its performance on simulated data sets.     

Space‐time cluster identification in point processes

The authors propose a new type of scan statistic to test for the presence of space‐time clusters in point processes data, when the goal is to identify and evaluate the statistical significance of localized clusters. Their method is based only on point patterns for cases; it does not require any specific knowledge of the underlying population. The authors propose to scan the three‐dimensional space with a score test statistic under the null hypothesis that the underlying point process is an inhomogeneous Poisson point process with space and time separable intensity. The alternative is that there are one or more localized space‐time clusters. Their method has been implemented in a computationally efficient way so that it can be applied routinely. They illustrate their method with space‐time crime data from Belo Horizonte, a Brazilian city, in addition to presenting a Monte Carlo study to analyze the power of their new test.     

Estimating the Effects of Residential Mobility: A Methodological Note

This article reviews the methodological challenges of estimating a causal association between mobility and children's cognitive, social, emotional, and physical development. Utilizing a comprehensive set of empirical articles published in the past 25 years that employ quantitative methods, it describes the limitations of previous studies and the innovative ways that researchers have attempted to deal with them. The concept of mobility is inconsistently operationalized along four dimensions: school versus residential, distance, timing, and frequency. Imprecise operationalization conflates different forms of mobility, which have differential effects on development. Attempts to estimate a causal association between mobility and development suffer from three sources of bias: selection, contextual shifts, and contemporaneous instigating events. (a) Methods that account for unobserved differences between mobile and nonmobile children have consistently shown smaller or even positive effects of mobility. (b) Moving can have a positive or negative effect on children's ecological contexts in ways that are systematically correlated with child development. (c) Moves are frequently catalyzed by changes in family structure and employment. The article concludes with recommendations for future research. Researchers should continue to engage fixed- and random-effect, matching, and instrumental variable techniques, each of which makes the question of causality explicit.     

Effects of strength and power training on neuromuscular variables in older adults

The purpose of this study was to compare the neuromuscular adaptations produced by strength-training (ST) and power-training (PT) regimens in older individuals. Participants were balanced by quadriceps cross-sectional area (CSA) and leg-press 1-repetition maximum and randomly assigned to an ST group (n = 14; 63.6 ± 4.0 yr, 79.7 ± 17.2 kg, and 163.9 ± 9.8 cm), a PT group (n = 16; 64.9 ± 3.9 yr, 63.9 ± 11.9 kg, and 157.4 ± 7.7 cm), or a control group (n = 13; 63.0 ± 4.0 yr, 67.2 ± 10.8 kg, and 159.8 ± 6.8 cm). ST and PT were equally effective in increasing (a) maximum dynamic and isometric strength (p < .05), (b) increasing quadriceps muscle CSA (p < .05), and (c) decreasing electrical mechanical delay of the vastus lateralis muscle (p < .05). There were no significant changes in neuromuscular activation after training. The novel finding of the current study is that PT seems to be an attractive alternative to regular ST to maintain and improve muscle mass.