Leadership in collective action

We extend the model of collective action in which groups compete for a budged by endogenizing the group platform, namely the specific mixture of public/private good and the distribution of the private good to group members which can be uniform or performance-based. While the group-optimal platform contains a degree of publicness that increases in group size and divides the private benefits uniformly, a success-maximizing leader uses incentives and distorts the platform towards more private benefits - a distortion that increases with group size. In both settings we obtain the anti-Olson type result that win probability increases with group size.

Measuring intergenerational earnings mobility in Spain: a selection-bias-free approach

This paper analyses intergenerational earnings mobility in Spain correcting for different selection biases. We address the co-residence selection problem by combining information from two samples and using the two-sample two-stage least square estimator. We find a small decrease in elasticity when we move to younger cohorts. Furthermore, we find a higher correlation in the case of daughters than in the case of sons; however, when we consider the employment selection in the case of daughters, by adopting a Heckman-type correction method, the diference between sons and daughters disappears. By decomposing the sources of earnings elasticity across generations, we find that the correlation between child's and father's occupation is the most important component. Finally, quantile regressions estimates show that the influence of the father's earnings is greater when we move to the lower tail of the offspring's earnings distribution, especially in the case of daughters' earnings.

Selection bias and unobservable heterogeneity applied at the wage equation of European married women

This paper utilizes a panel data sample selection model to correct the selection in the analysis of longitudinal labor market data for married women in European countries. We estimate the female wage equation in a framework of unbalanced panel data models with sample selection. The wage equations of females have several potential sources of.

Destruction of invariant curves in the restricted circular planar three body problem using comparison of action

"Vegeu el resum a l'inici del document del fitxer adjunt."

Are parties domocratizing themselves? the evolution of leardership selection in Spain (1977-2008)

The aim of this paper is to verify, for the Spanish case, whether between 1977 and 2008 has increased the internal democracy of the major political parties (PSOE, AP / PP, PCE / IU, PNV and CDC). To do this, we will focus on their leadership selection processes, one of the key elements associated with intra-party democracy. The paper is going to introduce data on four different dimensions of leadership selection: the certification process, the voting procedure, the inclusiveness of the selectorate and, finally, the degree of competitiveness. The results will show that have been few changes in the leadership selection processes of the Spanish political parties since 1977. However, the results of the Spanish case will also be used to suggest some preliminary links between the four dimensions.

Knowledge of Catalan, public/private sector choice and earnings: Evidence from a double sample selection model

This paper explores the earnings return to Catalan knowledge for public and private workers in Catalonia. In doing so, we allow for a double simultaneous selection process. We consider, on the one hand, the non-random allocation of workers into one sector or another, and on the other, the potential self-selection into Catalan proficiency. In addition, when correcting the earnings equations, we take into account the correlation between the two selectivity rules. Our findings suggest that the apparent higher language return for public sector workers is entirely accounted for by selection effects, whereas knowledge of Catalan has a significant positive return in the private sector, which is somewhat higher when the selection processes are taken into account.

Trade, firm selection, and innovation: the competition channel

The availability of rich firm-level data sets has recently led researchers to uncover new evidence on the effects of trade liberalization. First, trade openness forces the least productive firms to exit the market. Secondly, it induces surviving firms to increase their innovation efforts and thirdly, it increases the degree of product market competition. In this paper we propose a model aimed at providing a coherent interpretation of these findings. We introducing firm heterogeneity into an innovation-driven growth model, where incumbent firms operating in oligopolistic industries perform cost-reducing innovations. In this framework, trade liberalization leads to higher product market competition, lower markups and higher quantity produced. These changes in markups and quantities, in turn, promote innovation and productivity growth through a direct competition effect, based on the increase in the size of the market, and a selection effect, produced by the reallocation of resources towards more productive firms. Calibrated to match US aggregate and firm-level statistics, the model predicts that a 10 percent reduction in variable trade costs reduces markups by 1:15 percent, firm surviving probabilities by 1 percent, and induces an increase in productivity growth of about 13 percent. More than 90 percent of the trade-induced growth increase can be attributed to the selection effect.

La presa de consciència de les actituds a l'educació física en la formació inicial de mestres de primària

Aquest treball és el resultat d’un procés de reflexió al voltant de les actituds dins la Formació Inicial de mestres de primària d’Educació física. Es tracta, d’una primera aproximació d’anàlisi i interpretació sobre la presa de consciència d’actituds que fan els estudiants en la pràctica de l’Educació física. Les preguntes que em plantejo en aquesta recerca són el resultat de les dues parts que configura aquest treball. La primera pregunta, es centra en el marc teòric de l’estudi, donant resposta a les relacions que s’estableixen entre l’educació física i l’educació en valors en el currículum de primària d’Educació física i en la Formació Inicial de mestres. La segona pregunta, pretén donar resposta a la proposta pràctica i així, esbrinar el paper del joc motor en el treball educatiu de les actituds en la Formació Inicial de mestres de primària. Els aspectes teòrics que estudio analitzen la relació que s’estableix entre l’Educació física i les actituds dins el marc educatiu de la Formació Inicial de mestres de primària. I serà, a partir de la proposta pràctica quan el joc motor esdevindrà element d’aproximació en la presa de consciència d’actituds En el context de la Facultat d’Educació de la Universitat de Vic, i en l’assignatura d’Educació física i la seva Didàctica de 2n curs, els estudiants de mestres de primària d’Educació física són protagonistes del seu propi procés d’aprenentatge. Tenen la possibilitat d’experimentar el paper de mestres, a partir de la posada en pràctica d’un joc motor. A partir d’aquesta pràctica, he volgut conèixer quins són els components de la pràctica que possibiliten la presa de consciència de les actituds presents a les sessions de classe per promoure l’educació en valors. Els instruments utilitzats, en la realització d’aquest treball, són un qüestionari elaborat a partir d’una selecció i justificació de continguts actitudinals, i l’observació d’una fitxa sessió després de la pràctica. El treball de recerca se situa en un paradigma interpretatiu i pràctic. Es planteja comprendre la importància que té, en les sessions de classe d’educació física, el desenvolupament de processos d’acció i de reflexió en la formació inicial dels mestres de primària i així examinar i perfeccionar futures intervencions pràctiques, tant del professorat com dels estudiants de mestre.

Growth, selection and appropriate contracts

We study a dynamic model where growth requires both long-term investment and the selection of talented managers. When ability is not ex-ante observable and contracts are incomplete, managerial selection imposes a cost, as managers facing the risk of being replaced tend to choose a sub-optimally low level of long-term investment. This generates a trade-off between selection and investment that has implications for the choice of contractual relationships. Our analysis shows that rigid long-term contracts sacrificing managerial selection may be optimal at early stages of economic development and when access to information is limited. As the economy grows, however, knowledge accumulation increases the return to talent and makes it optimal to adopt flexible contractual relationships, where managerial selection is implemented even at the cost of lower investment. Better institutions, in the form of a richer contracting environment and less severe informational frictions, speed up the transition to short-term relationships.

Probiotic microorganisms: 100 years of innovation and efficacy. Modes of action

AbstractArticle StructureFigures and TablesReferences Benefits from probiotic micro-organisms have been recognised for over 100 years, and as being useful in poultry for 50 years. Fuller (1989) redefined probiotics as ‘a live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance’. Benefits derived from this improved intestinal microbial balance could be reflected in performance or prevention of pathogen colonisation. Probiotic micro-organisms use in poultry production has been widely accepted and new opportunities arose from the 2006 EU ban on antimicrobial growth promoters. The majority of microbial products for compound feeds are made up from a relatively small number of micro-organisms that are normally present in the GI tract. They include non-sporulated bacteria, sporulated bacteria, fungi or yeasts; and presented from single to multi-strain products. A review on the proposed modes of action is presented including recent approaches to quorum sensing interference

Family-based affirmative action? Subversion and resilience strategies of gay father families

The present doctoral dissertation is aimed at analyzing how and with what consequences gay father families and their children’s schools negotiate possible differences in the construction of family and gender at home and in the families’ social milieus. This objective fits in with the broader goal of researching how family-school interactons are influenced by the social context such as hegemonic masculinity (Connell, 2002). The thesis is based on qualitative fieldwork carried out with 18 nonheterosexual parent families in Spain, comprising 30 interviews with 44 people. The principal participant group were 14 de novo (adoptive and surrogacy) gay father families with resident preadolescent children. The findings revealed that all the de novo families assumed open communication strategies at school with inclusive consequences: apart from incidental questions and reactions of surprise, the children did not suffer homophobic bullying. The analisis showed that the necessary condition for inclusion was not the open communication but rather illocutionary orientation (Habermas, 1984; Soler & Flecha, 2010), understood as the parents’ sensitivity to the attitudes of their children and schools. The schools received the families in an inclusive manner, which, however, was only receptive and not proactive, therefore some of the families (reconstituted ones), coerced by the social context, got excluded. Gender relations at home were predominantly androgynous, and outside home predominantly traditional, yet the children negotiated this difference with inclusive consequences. They participated in hegemonic collective practices, thus confirming the thesis on the similarity between homo- and heterosexual-parent families (Golombok, 2006). Consistently, also the families’ identity politics was “assimilationist” and non-queer. Admittedly, the analisis showed that such a politics was increased by social expectations. Still, the findings suggest that educational and other family policies should draw on broad agendas of gender and family diversity rather than on the politics of difference and the unique status of LGB families.

Aproximació al canvi conceptual dels docents respecte a l'ensenyament estratègic de la lectura, a partir d'un curs de formació : una experiència al Cicle mitjà d'Educació Primària

Aquest projecte s'emmarca dins de l'àmbit de l'assessorament psicopedagògic, concretament, en la formació del professorat per a l'ensenyament d'estratègies d'aprenentatge. El tema d'estratègies d'ensenyament/aprenentatge és massa ampli per a poder tractar-lo en un projecte com aquest, amb una limitació temporal que exigeix concretar l'actuació en els punts següents: fer una selecció prèvia d'un determinat conjunt de procediments d'aprenentatge vinculats amb la lectura, situar-lo dins d'un context escolar concret de manera que la formació vagi dirigida als docents del cicle mitjà d'educació primària d'un CEIP del Masnou i centrar l'experiència en dos d'aquests docents.

Action Research : the first steps to start up a pilot experiment in heritage education

Peer-reviewed

Enhanced Model Selection for motion segmentation

In this paper a novel rank estimation technique for trajectories motion segmentation within the Local Subspace Affinity (LSA) framework is presented. This technique, called Enhanced Model Selection (EMS), is based on the relationship between the estimated rank of the trajectory matrix and the affinity matrix built by LSA. The results on synthetic and real data show that without any a priori knowledge, EMS automatically provides an accurate and robust rank estimation, improving the accuracy of the final motion segmentation

Electoral competition through issue selection

Politics must tackle multiple issues at once. In a first-best world, political competition constrains parties to prioritize issues according to the voters' true concerns. In the real world, the opposite also happens: parties manipulate voter priorities by emphasizing issues selectively during the political campaign. This phenomenon, known as priming, should allow parties to pay less attention to the issues that they intend to mute. We develop a model of endogenous issue ownership in which two vote-seeking parties (i) invest to attract voters with "better" policy proposals and (ii) choose a communication campaign to focus voter attention on specific issues. We identify novel feedbacks between communication and investment. In particular, we find that stronger priming effects can backfire by constraining parties to invest more resources in all issues, including the ones they would otherwise intend to mute. We also identify under which conditions parties prefer to focus on their "historical issues" or to engage in issue stealing. Typically, the latter happens when priming effects are strong, and historical reputations differentiates parties less.