Estimating the employer size-wage premium in a panel data model with comparative advantage and non-random selection

This paper considers the estimation of the employer-size wage e?ect using a panel of employer-employee matched data. We test for the possibility of different returns to observable human capital variables as well as examine the role played by unmeasured skills in driving the allocation of workers across firms of di?erent sizes. Our results show that some of the observed skills; namely, education, age, and tenure have high returns in large firms, while the opposite is true for high skilled occupations and for the gender gap. On the other hand, the price of non-observed skills is reduced as firm size increases. This finding is consistent with explanations based on the premise that large employers have more difficulty monitoring workers, which therefore leads them to monitor less closely.firm size, wages, non-random selection.

Private Information: Similarity as Compatibility

We investigate the continuity of equilibrium in differential information economies with a finite number of agents. In this setting, agents can make contingent contracts based on events that are commonly observed. With private information modelled as finite partitions of a compact and metrizable space of states of nature, we introduce a topology on information that takes into account the compatibility of information fields in assessing similarity between private information fields. This topology allows us to establish upper semicontinuity of the private core correspondence.Differential Information Economy, Asymmetric Information, Radner Equilibrium, Private Core, Topologies on Information.

General equilibrium with private state verification

We study general equilibrium with private and incomplete state verification. Trade is agreed ex ante, that is, before private information is received. It is useful to define a list of bundles as a derivative good that gives an agent the right to receive one of the bundles in the list. Enforceable trade agreements can be described by Pi-measurable plans of lists of bundles, instead of Pi-measurable plans of bundles as in Radner (1968). In equilibrium, the price of a list coincides with the price of the cheapest bundle in the list, and it is always the cheapest bundle of the list that is delivered. This property leads to a system of linear inequalities which are deliverability constraints on the choice set. We investigate existence of equilibrium in the case in which preferences are Pi-measurable. If there is a perfectly informed trader in the economy, existence of equilibrium is guaranteed.General equilibrium, Differential information, Verifiability, Uncertain delivery, Lists of bundles, Rational expectations

Existence and generic efficiency of equilibrium in two-period economies with private state-verification

Private state-verification is introduced in a two-period economy with spot markets in both periods and complete futures markets for contingent delivery in the second period. Existence of equilibrium is established, under standard assumptions. The equilibrium allocation is shown to be generically efficient if the number of states is not greater than the number of goods.General equilibrium, Differential information, Private state-verification, Two-period economies, Existence of equilibrium, Generic efficiency

Contracts for uncertain delivery

We propose the notion of objects of choice as uncertain consumption bundles, extending the formulation of Arrow (1953). Agents sign “contracts for uncertain delivery”, which specify a list of alternative bundles, instead of a single one. This allows us to incorporate uncertainty and asymmetric information in the model of Arrow-Debreu. Relatively to the model of Radner (1968), efficiency of trade is increased and some “no trade” situations are avoided, while the classical results still hold: existence of core and competitive equilibrium, core convergence, welfare theorems, etc.Uncertainty, Asymmetric information, Private information, Contingent delivery, Radner equilibrium.

Modeling the influence of formalin fixation time on the elemental constitution of human tissues

Cancer is a leading cause of death worldwide, accounting for nearly 9.6 million deaths. Therefore, an early and accurate diagnosis is essential. Trace elements are essential and are linked with toxicity when they exist in abnormal quantities. Thus, understanding the mechanisms of assimilation/accumulation of trace elements may be indicative of the genesis or progression of certain diseases, such as carcinogenesis. X-rays have been employed in the medical system since its discovery, particularly for diagnostics and treatments. Micro Energy Dispersive X-ray Fluorescence (μEDXRF) is used as a multielement analysis technique of trace elements, once it measures non- destructively actual tissue levels of elements in very small portion of tissue, and it was the chosen one for this Master Thesis. Previous studies show that the formalin fixation time influences the elemental composition present on the tissue, focusing on the drastic decrease of K and Cl after 48 hours. In order to have an accurate quantification of this elements, we need to study the influence of formalin fixation time on tissues. In this work, 6 sets of muscle tissues, from Instituto Português de Oncologia (IPO), submitted to different fixation times in formalin were analyzed with the goal to param- eterize the influence of formalin fixation time on the elemental constitution of human tissues, focusing on 9 trace elements - K, Zn, Cl, P, S, Cu, Fe, Mn and Ca. The quantitative analysis was done using Certified Reference Materials (CRMs) to build elemental cali- bration curves. All the data was treated in different ways, namely with ROOT software - removing background and identifying each elemental peaks - and with the Compton-to- Rayleigh Ratio correction, in order to minimize errors and improve accuracy. Statistical tests, Shapiro-Wilk was performed to test the normality of the distributions of each ele- ment and Kruskal-Wallis ANOVA to compare the tissues with different fixation times. The results obtained, confirmed what it was expected, showing that the K and Cl concentrations dramatically decrease in the first 3 hours of formalin fixation time.O cancro é uma das principais causas de morte em todo o mundo, sendo responsável por quase 9,6 milhões de mortes. Portanto, um diagnóstico precoce e preciso é essencial. Os elementos traço são essenciais e estão ligados à toxicidade quando existem em quanti- dades anormais. Assim, a compreensão dos mecanismos de assimilação/acumulação de elementos traço pode ser um indicativo do aparecimento ou progressão de certas doenças, como a carcinogénese. Os raios-X têm sido usados no sistema médico desde sua descoberta, principalmente para diagnósticos e tratamentos. A μEDXRF é utilizada como técnica de análise multiele- mentar de elementos traço, uma vez que mede, de uma forma não destrutiva elementos numa porção muito pequena de tecido, e foi a técnica escolhida para esta Dissertação de Mestrado. Estudos anteriores mostram que o tempo de fixação em formol influencia a composição elementar presente no tecido, focando na diminuição drástica de K e Cl após 48 horas. Para uma quantificação precisa desses elementos, precisamos estudar a influência do tempo de fixação em formol nos tecidos. Neste trabalho, 6 conjuntos de tecidos musculares, do IPO, submetidos a diferentes tempos de fixação em formol foram analisados com o objetivo de parametrizar a influên- cia do tempo de fixação em formol na constituição elementar dos tecidos humanos, com foco em 9 elementos traço - K, Zn, Cl, P, S, Cu, Fe, Mn e Ca. A análise quantitativa foi feita utilizando CRMs para construir curvas de calibração elementares. Todos os dados foram tratados de diferentes formas, nomeadamente com software ROOT - removendo o fundo e identificando cada pico elementar - e com a correção Compton-to-Rayleigh Ratio, de forma a minimizar erros e melhorar a precisão. Foram usados testes estatísti- cos, nomeadamente o Shapiro-Wilk para testar a normalidade das distribuições de cada elemento e o Kruskal-Wallis ANOVA para comparar os tecidos com diferentes tempos de fixação. Os resultados confirmaram o esperado, mostrando que as concentrações de K e Cl dramaticamente nas primeiras 3 horas de fixação em formol