Urban growth,policy and planning of public space

Under the pressure of the urbanizing tsunami, town planning and urban policies in Spain have given a residual treatment to public spaces in recent urban development. This work proposes a brief but comprehensive sociological analysis about social and morphological traits of public spaces – like paradigmatic social space – in order to show the city's irreplaceable role in citizen socialization processes. The network of streets and places, the city in this sense, make up the scenes of man's sociability. In this perspective, planning ought to be geared towards and for the city and redeem a civic impetus that pursues developing the whole instead of subjecting it.     

How and when a salesperson's perception of organizational politics relates to proactive performance

Politics in the workplace is a reality of organizational life. Several studies have investigated the negative implications of perceived organizational politics on various work attitudes and performance measures but not on proactive performance. However, proactive performance is important in a sales context because salespeople operate in an uncertain environment, and some task aspects cannot be formalized. Moreover, there is still a need for research to analyse the psychological mechanisms that lead perceived organizational politics to cause negative reactions from employees as well as to provide new insights on the boundary conditions of this process. Therefore, we examine the effect of perceived organizational politics on proactive performance through a salesperson's trust in the sales manager, as well as the moderating role of the salesperson's experience.This study uses dyadic data from 192 salespeople and their sales managers from a range of industries. The model entails a moderated mediation process. Results support the proposed model. The findings contribute to the salesforce management literature by suggesting the need to consider the importance of perceived organizational politics and by aiding in the understanding of how and when it hinders proactive performance.     

Risk and Protective Factors for Early Substance Use Initiation: A Longitudinal Study of Mexican‐Origin Youth

Substance use initiation in adolescence is a critical issue, given its association with substance dependency and associated problems in adulthood. However, due to the dearth of fine‐grained longitudinal studies, the factors associated with early initiation are poorly understood, especially in minority youth. The present study examined substance use initiation in a sample of Mexican‐origin youth (n = 674) assessed annually from age 10 to 16. Using discrete‐time survival analyses, we found that initiation escalated rapidly from late childhood to adolescence, and we identified a wide range of factors, from the individual to the cultural level of analysis, that significantly increased or decreased risk for early initiation. These findings have important implications for programs aimed at preventing early substance use by Mexican‐origin youth.     

Asymmetric matrix-valued covariances for multivariate random fields on spheres

ABSTRACT

Matrix-valued covariance functions are crucial to geostatistical modelling of multivariate spatial data. The classical assumption of symmetry of a multivariate covariance function is overly restrictive and has been considered as unrealistic for most of the real data applications. Despite of that, the literature on asymmetric covariance functions has been very sparse. In particular, there is some work related to asymmetric covariances on Euclidean spaces, depending on the Euclidean distance. However, for data collected over large portions of planet Earth, the most natural spatial domain is a sphere, with the corresponding geodesic distance being the natural metric. In this work, we propose a strategy based on spatial rotations to generate asymmetric covariances for multivariate random fields on the d-dimensional unit sphere. We illustrate through simulations as well as real data analysis that our proposal allows to achieve improvements in the predictive performance in comparison to the symmetric counterpart.     

Estimation of slowly time-varying trend function in long memory regression models

ABSTRACT

We study the asymptotic properties of the least-squares estimator for the trend function of a particular class of locally stationary models, which are defined by considering a smooth variation of the trend function. Additionally, errors are assumed to be realizations from a long-range dependent stationary Gaussian process. Our findings are then illustrated through Monte Carlo simulations.     

The Leverage of Demographic Dynamics on Carbon Dioxide Emissions: Does Age Structure Matter?

This article provides a methodological contribution to the study of the effect of changes in population age structure on carbon dioxide (CO₂) emissions. First, I propose a generalization of the IPAT equation to a multisector economy with an age-structured population and discuss the insights that can be obtained in the context of stable population theory. Second, I suggest a statistical model of household consumption as a function of household size and age structure to quantitatively evaluate the extent of economies of scale in consumption of energy-intensive goods, and to estimate age-specific profiles of consumption of energy-intensive goods and of CO₂ emissions. Third, I offer an illustration of the methodologies using data for the United States. The analysis shows that per-capita CO₂ emissions increase with age until the individual is in his or her 60s, and then emissions tend to decrease. Holding everything else constant, the expected change in U.S. population age distribution during the next four decades is likely to have a small, but noticeable, positive impact on CO₂ emissions.     

How High is Hispanic/Mexican Fertility in the United States? Immigration and Tempo Considerations

In this article, I demonstrate that the apparently much higher fertility of Hispanic/Mexican women in the United States is almost exclusively the product of period estimates obtained for immigrant women and that period measures of immigrant fertility suffer from three serious sources of bias that together significantly overstate fertility levels: difficulties in estimating the size of immigrant groups; the tendency for migration to occur at a particular stage in life; and, most importantly, the tendency for women to have a birth soon after migration. When these sources of bias are taken into consideration, the fertility of native Hispanic/Mexican women is very close to replacement level. In addition, the completed fertility of immigrant women in the United States is dramatically lower than the level obtained from period calculations. Findings are consistent with classical theories of immigrant assimilation but are a striking departure from the patterns found in previous studies and published statistics. The main implication is that without a significant change in immigration levels, current projections based on the premise of high Hispanic fertility are likely to considerably exaggerate Hispanic population growth, its impact on the ethno-racial profile of the country, and its potential to counteract population aging.     

Sociality enhances birds’ capacity to deal with anthropogenic ecosystems

Urban species often adjust their behavior to survive in urban environments, characterized by the proximity of humans, habitat fragmentation and heterogeneous, fluctuating ecological resources. Several hypotheses have been put forth to explain how species manage living in heterogeneous and complex anthropogenic habitats. The ability of individuals or species to beneficially modify their behaviors in response to changes in the environment has indeed been alternatively explained based on phylogenetic, adaptive, and ontogenic arguments. In this study we investigated the role of sociality as a driver of behavioural flexibility in urban birds. Sociality can be defined as the tendency to associate with conspecifics or form a group and may influence a species’ ability to survive in an urban ecosystem to the extent that it represents advantages to species or individuals in terms of resource exploitation, fitness, and predation risk-avoidance. Given the potential benefits of sociality we hypothesized that sociality is a further characteristic that may explain how species have successfully expanded their range into urbanized areas. Based on this hypothesis, we predicted that pigeons (Columba livia) will show higher behavioural flexibility when in larger groups, whatever their genetic background and living-circumstances. Using pigeons as a model system, we compared 27 groups in France and Italy composed of four different genetic strains and varying living-conditions: free-living feral pigeons in urban areas, free-living domestic pigeons at the property of a local breeder captive, feral pigeons in a French ecological field station, captive domestic pigeons in an Italian ecological station. We tested two standardized behavioral measures of behavioural flexibility: thresholds for fear or neophobia and rates of problem solving. We found that group number affects neophobia and to a lesser extent problem-solving, suggesting that sociality is a factor enhancing birds’ faculties to establish in and cope with heterogeneous urban environments. We consider this hypothesis here as compatible and complementary to existing hypotheses on species’ adaptation to urban ecosystems.     

Satisfaction with the country and well-being: future expectations / Satisfacción con el país y bienestar: expectativas acerca del futuro

The role of expected personal well-being in the perception of the improvement (or deterioration) in living conditions and country satisfaction is analysed, as well as the relationship between the latter and life satisfaction and personal happiness. A national sample of N = 10,654 participants was used, collected through probabilistic, stratified, two-stage and cluster sampling. They responded to the Mexican Encuesta Nacional de Gastos de los Hogares (National Household Spending Survey, ENGASTO), which measures the spending on goods and services, aspects related to satisfaction with life and the country, and expectations of future personal well-being. Correlational analyses show positive associations between perceptions of the country and its expected development on the one hand and participants’ well-being on the other. Expectations of future personal well-being show indirect effects for both the relationship between the perception of improvement (or deterioration) of living conditions and country satisfaction, and the relation between the latter, happiness and life satisfaction.