Analysis of the non-native flora of Ensenada, a fast growing city in northwestern Baja California

Urbanized areas show a high proportion of non-native plants and can work as dispersal points to the surrounding areas. Ensenada is a fast growing city located in the northwestern peninsula of Baja California (Mexico). It is the southern extreme of a bi-national, coastal urban corridor that extends from Los Angeles, California south to Ensenada. This corridor is part of the biodiversity hotspot of the California Floristic Province. The aim of this study was to analyze the composition and distribution of the spontaneous flora in the city of Ensenada. We systematically sampled two differentiated urban environments, vacant lots and arroyos, in 2006 and 2007. We found a total of 158 plant species, 61% of them were non-native species. Arroyo areas showed higher non-native species richness than vacant lots (21.9 vs. 13.6 species/transect) and could be potential dispersal vectors for non-native species to natural areas outside of the city, or in the reverse direction also.     

Accuracy of approximate progressively censored reliability sampling plans for exponential models

Reliability sampling plans provide an efficient method to determine the acceptability of a product based upon the lifelengths of some test units. Usually, they depend on the producer and consumer’s quality requirements and do not admit closed form solutions. Acceptance sampling plans for one- and two-parameter exponential lifetime models, derived by approximating the operating characteristic curve, are presented in this paper. The accuracy of these approximate plans, which are explicitly expressible and valid for failure and progressive censoring, is assessed. The approximation proposed in the one-parameter case is found to be practically exact. Explicit lower and upper bounds on the smallest sample size are given in the two-parameter case. Some additional advantages are also pointed out.     

Skew-normal alpha-power model

In this paper, authors study properties and inference for the newly introduced skew-normal alpha-power model, generalizing both, the power-normal and skew-normal models. Inference is approached via maximum likelihood. Fisher information matrix is derived and shown to be nonsingular at the whole parametric space. Special emphasis is placed on the special case of the power–skew-normal model. Studies with real data illustrate the fact that the model can be very useful in applications, being able to overfit less general models entertained in the literature.     

Volunteering and the strategic value of ignorance

Private provision of public goods often takes place as a war of attrition: individuals wait until someone else volunteers and provides the good. After a certain time period, however, one individual may be randomly selected. If the individuals are uncertain about their cost of provision, but can find out about this cost ahead of the volunteering game, a strategic value is attached to the information, and individuals may prefer not to learn their cost of provision. If the time horizon is sufficiently short, in equilibrium only one individual may acquire information about his cost. For a long time horizon, acquiring information is strictly dominant. The time limit is an important instrument in influencing the efficiency of the volunteering game.     

Working mothers’ decisions on childcare: the case of Spain

This paper aims to analyze household decisions regarding the childcare of young children. We present two specifications. The first one assumes a sequential decision process. Firstly, parents choose between paid or unpaid care and, secondly, those who opt for paid childcare must decide whether to take their children to a nursery or pre-school or employ somebody to care for them. The second specification is a multinomial Logit in which it is assumed that parents choose from three alternatives: unpaid care, paid care by a nanny, and center-based care. We apply our models to a sample of working mothers with children under three. The database used is the 2008–2010 Spanish Survey of Quality of Working Life (Encuesta de Calidad de Vida en el Trabajo). The results are in line with previous work: Parental education, family composition, income and the characteristics of the mother’s job are important factors in determining the type of childcare chosen for under-three-year-olds.     

Rational-experiential thinking style and rational intergroup cooperation: the moderating role of intergroup conflict / Estilos de pensamiento racional-experiencial y la cooperación intergrupal racional: el rol modulador del conflicto intergrupal

Cooperative relationships between groups are difficult because of the high human capability to differentiate between in-group vs. out-group members. This obstacle exists even when the groups can obtain benefits for themselves from cooperation with other groups (rational cooperation). Based on an interactionist approach, the authors propose that personal (individual differences) and situational (conflicts) factors contribute to rational intergroup cooperation. The authors conducted a preliminary correlational study (Study 1) and an experimental investigation (Study 2). In Study 1, the authors examined, with 105 participants, the psychometric properties of the Spanish version of the Rational–Experiential Inventory (REI), measuring individual differences in information processing. In Study 2, the authors conducted an experimental investigation with 141 participants, testing the role of individual differences and conflict in intergroup rational cooperation. Findings of Study 1 showed that the scale has adequate psychometric properties. Results of Study 2 confirmed that the existence of both manipulated and perceived intergroup conflict reduces the magnitudes of the relationships between rational ability and rational cooperation. In addition, perceived intergroup conflict increased the magnitude of the links from experiential ability and experimental engagement to rational cooperation. Both individual differences and previous conflict have a role in predicting rational intergroup cooperation. According to the interactionist approach, personal and situational factors should be considered in the understanding of intergroup relationships.     

Social Accountability as an Innovative Frame in Civic Action: The Case of Rede Nossa São Paulo

In the past three decades, Brazil’s state and civil society have undergone a transformation. Non-profit organizations have proliferated, revealing new opportunities for participation, while sustainability and corporate social responsibility have produced new agendas for corporations. Against this background, accountability has emerged within the debate, particularly with regard to governmental transparency and efficiency. This paper examines the Rede Nossa São Paulo movement, which pledges social justice and sustainability and promotes social accountability as its main strategy to achieve its mission. Thus, the main objective of this study is to understand social accountability; more broadly, the goal is to examine governmental accountability in the mobilization process developed by Rede Nossa São Paulo by referring to the framing perspective as a core aspect in the understanding of social movements. Social accountability is presented as a frame that is composed of the union between movements that are historically bonded by the motto of social justice and other groups that are related to urban development and social and environmental responsibility.     

Who performs a stronger response to whom? Detecting individual competitive actions and reactions

This study analyzes the degree of competition through individual actions and reactions. Empirical support for this analysis has derived mainly from structural econometric models describing the nature of competition. This analysis extends the existing literature by empirically considering a direct measurement of competition through the analysis of the competitive actions and responses, and describing how firms compete within and between strategic groups. We estimate the firms’ conduct in the Spanish deposits market with 146 firms and 18,888 observations. This is a specially compelling context for the banking industry, in which a deregulation process gives rise to the adoption of aggressive strategies seeking to increase the market shares of deposit accounts; thus, producing a turbulent situation of increasing rivalry. Our results offer a deeper understanding of the firms’ competitive behavior, since we identify different patterns of actions and reactions depending upon the strategic group the firm belongs to.     

Modified minimax estimation of regression coefficients

Working with the linear regression model (1.1) and having the extraneous information (1.2) about regression coefficients the problem exists how to build estimators (1.3) with the risk (1.4) which enable to utilize the known information in order to reduce their risk as compared with the risk (1.6) of the LSE (1.5). Solution of this problem is known for the positive definite matrix T, namely in form for estimators (1.8) and (1.10).First, it is shown that the proposed estimators (2.6),(2.9) and (2.16) based on psedoinversions of the matrix L represent the solution of the problem of the positive semidefinite matrix T=L'L.Further, the problem of interpretability of estimators in the sense of the inequality (3.1) exists; it is shown that all mentioned estimators are at least partially interpretable in the sense of requirements (3.2) or (3.10).     

Firm Ownership and Rent Sharing

In this paper we analyse—theoretically and empirically—how the degree of private versus public ownership of firms affects the degree of rent sharing between firms and their workers. Using a particularly rich linked employer-employee dataset from Portugal, covering a large number of corporate ownership changes across a wide spectrum of economic sectors over more than 20 years, we find that rent sharing is significantly higher in firms with a larger share of private ownership. Estimates from our most preferred empirical specification suggest that an increase in the private ownership share of 10 percentage points increases (on average) the rent-sharing elasticity by 0.0002. Based on a theoretical analysis that incorporates union-firm wage bargaining and efficiency wage effects within the same modelling framework, this result cannot be explained by private firms being more profit oriented than public ones. However, the result is consistent with a scenario whereby privatisation leads to less job security for workers, implying stronger efficiency wage effects.