Price Discrimination in Many-to-Many Matching Markets

We study second-degree price discrimination in markets where the product traded by the monopolist is access to other agents. We derive necessary and sufficient conditions for the welfareand the profit-maximizing mechanisms to employ a single network or a menu of non-exclusive networks. We characterize the optimal matching schedules under a wide range of preferences, derive implications for prices, and deliver testable predictions relating the structure of the optimal pricing strategies to conditions on the distribution of match qualities. Our analysis sheds light on the distortions associated with the private provision of broadcasting, health insurance and job matching services. JEL Classification Numbers:D82matching, two-sided markets, networks, adverse selection, incentives, mechanism design

Quantitative and Qualitative Assessment of Adolescents’ Future Time Perspective

O desenvolvimento de perspectivas temporais de futuro (PTF) na adolescência tem sido associado a comportamentos adaptativos em contexto escolar. Contudo, persiste a necessidade de compreensão de como essas PTF são construídas. Neste trabalho, apresentamos dois estudos sobre a PTF, destacando a sua ligação com a experiência presente. Os participantes foram adolescentes com idades entre 14 e 18 anos. No primeiro estudo (N = 551), analisamos a estrutura fatorial de um questionário construído para avaliar a PTF em contexto escolar. Identificamos uma associação significativa entre desempenho académico e PTF. No segundo estudo (N = 11), através de uma análise, fundada na Grounded Theory, de dados qualitativos decorrentes de entrevistas, verificamos que os adolescentes se preocupam com o seu futuro, referindo-se predominantemente a dimensões relacionadas com a carreira. Tais resultados apontam ainda para a influência que diferentes agentes educativos e a participação em múltiplas atividades têm no seu pensamento prospetivo.El desarrollo de perspectivas de futuro (PTF) en la adolescencia se asocia con varias conductas adaptativas en contexto escolar. Sin embargo, sigue existiendo la necesidad de comprender cómo se construyen estas PTF. En este trabajo se presentan dos estudios sobre la PTF, destacando su conexión con la experiencia presente. Los participantes fueron adolescentes de 14 hasta 18 años. En el primer estudio, se analiza la estructura factorial de los resultados de un cuestionario diseñado para evaluar la PTF en contexto escolar. Fue encontrada además una asociación significativa entre PTF y el rendimiento académico. En el segundo estudio, a través de un análisis basado en la Grounded Theory a datos cualitativos obtenidos de entrevistas, se encontró que los adolescentes se preocupan por su futuro, refiriéndose predominantemente a dimensiones relacionadas con la carrera. Estos resultados también apuntan hacia la influencia de los diferentes agentes educativos y de participación en múltiples actividades en su visión de futuro.Developing perspectives concerning the future in adolescence has been associated with several adaptive behaviors in school context. However, a need to understand how these prospects are build remains. In this paper, two studies on adolescents’ future time perspective (FTP) are presented, highlighting its connection to the present experience. Participants were adolescents, aged 14 to 18. In the first study (N = 551), it is analyzed the factorial structure of a questionnaire designed to assess FTP in school context. A significant association of academic performance with FTP was found. In the second study (N = 11), through an analysis, based on Grounded Theory, to qualitative data derived from interviews, it was found that adolescents think considerably about their future, despite showing to be predominantly focused on career related dimensions. The influence on prospective thinking of both educational agents of the participation in multiple activities was also identified

Catching up lives in the trash: the case of a recycling cooperative in Santa Maria-DF, Brazil

Tomando como objeto de estudo o caso de uma cooperativa de trabalho de reciclagem em Santa Maria-DF, foram trabalhadas algumas dimensões profissionais e pessoais da vida de catadores e catadoras, tendo como objetivo conhecer as suas perspetivas sobre as condições profissionais, pessoais e sociais enquanto profissionais da catação de resíduos sólidos organizados em cooperativa de trabalho de reciclagem, identificando quais as suas principais dificuldades, constrangimentos e necessidades e procurando conhecer de que forma o movimento cooperativista de trabalho de reciclagem contribui para o possível desenvolvimento dos seus processos de inclusão social. Do ponto de vista metodológico e técnico optou-se por uma abordagem qualitativa, com a realização de entrevistas e o desenvolvimento de observação. Foi possível perceber que os catadores/as não estão socialmente inseridos, carecem de educação, saúde, renda, laboram em precárias condições de trabalho, correspondem a um grupo altamente vulnerável, em que pese o cooperativismo de trabalho, via cooperativa de reciclagem proporcionar o emprego na catação tal pode considerar-se como a face perversa da inclusão.cooperative of work of recycling in Santa Maria-DF. Based on the analysis of some professional and personal dimensions of the life of waste pickers, it aims to know their perspectives on the professional, personal and social conditions as solid waste disposal workers organized in a recycling work cooperative, identifying their main difficulties, constraints and needs and seeking to know how the cooperative movement of recycling work contributes to the possible development of social inclusion processes. From the methodological and technical point of view, a qualitative approach was chosen, with the accomplishment of interviews and the development of observation. It was observed that the collectors are not socially inserted; they lack education, health, income; working conditions are precarious. They are a highly vulnerable group. Although included in cooperative work, this can be considered as the perverse face of inclusion.info:eu-repo/semantics/publishedVersio

Many-to-many matching and price discrimination

We study centralized many-to-many matching in markets where agents have private information about (vertical) characteristics that determine match values. Our analysis reveals how matching patterns reflect cross-subsidization between sides. Agents are endogenously partitioned into consumers and inputs. At the optimum, the costs of procuring agents-inputs are compensated by the gains from agents-consumers. We show how such cross-subsidization can be achieved through matching rules that have a simple threshold structure, and deliver testable predictions relating the optimal price schedules to the distribution of the agents’ characteristics. The analysis sheds light on the practice of large matching intermediaries, such as media and business-to-business platforms, advertising exchanges, and commercial lobbying firms

Flow of Taylor bubbles rising in stagnant non-Newtonian fluids

Tese de mestrado. Faculdade de Engenharia. Universidade do Porto. 199

Genetic and functional analyses of the developing asymmetric zebrafish habenula

The vertebrate brain develops anatomical and functional left-right asymmetries in localised regions, without affecting the laterality of the surrounding structures. To understand how brain laterality develops, we studied the development of robust habenular asymmetries in larval zebrafish. The left and right dorsal habenulae (dHb) have different sizes, asymmetric patterns of gene expression and establish distinct afferent and efferent connections. Although we are beginning to understand the molecular pathways that establish these asymmetries, the pathways underlying formation of the habenular progenitors remains largely elusive. Also, despite several habenular gene expression patterns being broadly asymmetric, there are no habenular markers for smaller habenular neuronal subpopulations in 4 dpf zebrafish. Lastly, we still need to investigate the importance of habenular asymmetry for its correct function and normal behaviour. This thesis aims to tackle these three gaps in habenular asymmetry research. To do so, we first characterised the A66u757 mutant, which develops a smaller and symmetric habenula. The causative mutation is in the rerea gene, which encodes a co-regulator of nuclear receptors that modulates the expression of fgf8. In line with this, the pattern of fgf8 expression is expanded in the diencephalon of mutants, and the parapineal is malformed, as observed in other FGF signalling mutants. Lastly, we show that the habenular phenotype of these mutants is concomitant with a delay in the formation of habenular progenitors. Second, to understand which neuronal subpopulations compose the zebrafish habenula at 4 dpf, we developed a protocol to obtain habenular single cells for RNA sequencing. Cells collected from the left and right nuclei still express habenular genes in an asymmetric fashion. However, to increase the number of collected cells, we harvested GFP-positive cells from a transgenic line that expresses GFP in the dHb and in the olfactory organ. Consequently, we sequenced 586 cells, which were separated into dHb, ventral habenula and olfactory organ clusters. However, due to the relatively small number of sequenced cells, we did not manage to discriminate subpopulations of the dHb. We propose optimisation steps that will allow us to finish this work. Lastly, to study the role of habenular asymmetry in behaviour, we tested two habenular mutants in an operant learning paradigm, through the ROAST assay. We show that wild-type and left-isomerised dHb mutant larvae learn to terminate an aversive stimulus by changing the direction of a stereotypical aversive-heat-response. Despite not finding differences between these mutants and wild-types, we did not exclude the role of the habenula in this assay and propose future research to further test this function

Students’ Characteristics and Teachers’ Estimates about Their Academic Achievement

The relation between teachers’ expectations and students’ academic achievement has received considerable interest in the education and psychology domains. In this study, we analyze the extent to which the information about students influences the formulation of teachers’ estimates about their achievement. The sample consisted of 491 Portuguese teachers, aged between 26 and 82 years old (M age = 43 years). To assess the teachers’ estimates, we created excerpts containing information about hypothetical students, in relation to whom an estimate of academic success was required. Each excerpt had two versions (A and B), according to the more or less favorable information regarding students’ intellectual, family, self-regulation, and previous performance variables. The results show moderate differences between the estimates of the participants that received version A and those that received version B. The results are discussed considering the importance of a set of student characteristics for the way teachers develop estimates about student performance.La relación entre las expectativas de los profesores y el rendimiento académico de los estudiantes ha sido investigada con gran interés. En este estudio se analiza la influencia de la información sobre los estudiantes, en la formulación de estimaciones docentes acerca de sus rendimientos académicos. La muestra estuvo compuesta por 491 profesores, comprendidos entre los 26 y 82 años de edad (M edad = 43). Para evaluar las estimaciones, fueron creados diferentes extractos con información sobre estudiantes hipotéticos, acerca de los cuales era solicitada una estimación de éxito académico. Cada extracto poseía dos versiones (A y B), sobre la información del estudiante, más o menos favorable sobre variables intelectuales, sociodemográficas, familiares, autorregulación y rendimiento académico anterior. Los resultados muestran diferencias moderadas entre las estimaciones de los participantes que recibieron la versión A y las efectuadas por los que recibieron la versión B. Lo anterior, permite arribar a la conclusión de que aquellas características son relevantes para los profesores para realizar sus estimaciones, relativas al desempeño académico de los estudiantes.A relação entre as expectativas dos professores e o desempenho acadêmico dos estudantes tem recebido muito interesse da investigação. Neste estudo, analisamos a extensão em que a informação sobre os estudantes influencia as estimativas docentes acerca do seu potencial desempenho acadêmico. A amostra consistiu em 491 professores, com idades entre 26 e 82 anos (M idade = 43). Para avaliar as estimativas, foram criados diferentes excertos contendo informação sobre estudantes hipotéticos, acerca dos quais era solicitada estimativa de sucesso escolar. Cada excerto tinha duas versões (A e B), conforme a informação sobre o estudante fosse mais ou menos favorável, relativamente a variáveis intelectuais, sociodemográficas, autorregulação e desempenho anterior. Os resultados mostram diferenças moderadas entre as estimativas dos participantes que receberam a versão A, comparativamente aos que receberam a versão B, permitindo concluir que aquelas características são relevantes na forma como os docentes desenvolvem estimativas acerca do desempenho acadêmico dos estudantes

Differential Taxation and Occupational Choice

We develop a framework to study optimal sector-specific taxation, where each agent chooses an occupation by comparing her skill differential with the tax burden differential across sectors. Because skills are not perfectly transferable, the Diamond-Mirrlees theorem (according to which the second-best entails production efficiency) fails: social welfare can be increased by inducing some agents to join the sector in which their productivity is not the highest. At the optimum, income taxes balance the marginal losses from inter-sector migration with the marginal gains from tailoring tax schedules to the distribution of productivities in each sector (“tagging”). A calibrated model indicates that sector-specific taxation generates substantive welfare gains when skill transferability decreases with income, as it enables the government to increase average taxes on high earners with large wage premia

Differential Taxation and Occupational Choice

We develop a framework to study optimal sector-specific taxation, where each agent chooses an occupation by comparing her skill differential with the tax burden differential across sectors. Because skills are not perfectly transferable, the Diamond-Mirrlees theorem (according to which the second-best entails production efficiency) fails: social welfare can be increased by inducing some agents to join the sector in which their productivity is not the highest. At the optimum, income taxes balance the marginal losses from inter-sector migration with the marginal gains from tailoring tax schedules to the distribution of productivities in each sector (“tagging”). A calibrated model indicates that sector-specific taxation generates substantive welfare gains when skill transferability decreases with income, as it enables the government to increase average taxes on high earners with large wage premia