Human melanoblasts in culture: Expression of BRN2 and synergistic regulation by fibroblast growth factor-2, stem cell factor, and endothelin-3

The BRN2 transcription factor (POU3F2, N-Oct-3) has been implicated in development of the melanocytic lineage and in melanoma. Using a low calcium medium supplemented with stem cell factor, fibroblast growth factor-2, endothelin-3 and cholera toxin, we have established and partially characterised human melanocyte precursor cells, which are unpigmented, contain immature melanosomes and lack L-dihydroxyphenylalanine reactivity. Melanoblast cultures expressed high levels of BRN2 compared to melanocytes, which decreased to a level similar to that of melanocytes when cultured in medium that contained phorbol ester but lacked endothelin-3, stem cell factor and fibroblast growth factor-2. This decrease in BRN2 accompanied a positive L-dihydroxyphenylalanine reaction and induction of melanosome maturation consistent with melanoblast differentiation seen during development. Culture of primary melanocytes in low calcium medium supplemented with stem cell factor, fibroblast growth factor-2 and endothelin-3 caused an increase in BRN2 protein levels with a concomitant change to a melanoblast-like morphology. Synergism between any two of these growth factors was required for BRN2 protein induction, whereas all three factors were required to alter melanocyte morphology and for maximal BRN2 protein expression. These finding implicate BRN2 as an early marker of melanoblasts that may contribute to the hierarchy of melanocytic gene control.

Nitrification of high strength ammonia wastewtaer treatment - process selection is the major factor.

Biological nitrogen removal via the nitrite pathway in wastewater treatment is very important in Saving the cost of aeration and as an electron donor for denitrification. Wastewater nitrification and nitrite accumulation were carried out in a biofilm airlift reactor with autotrophic nitrifying biofilm. The biofilm reactor showed almost complete nitrification and most of the oxidized ammonium was present as nitrite at the ammonium load of 1.5 to 3.5 kg N/m3.d. Nitrite accumulation was stably achieved by the selective inhibition of nitrite oxidizers with free ammonia and dissolved oxygen limitation. Stable 100% conversion to nitrite could also be achieved even under the absence of free ammonia inhibition on nitrite oxidizers. Batch ammonium oxidation and nitrite oxidation with nitrite accumulating nitrifying biofilm showed that nitrite Oxidation was completely inhibited when free ammonia is higher than 0.2 mg N/L. However, nitrite oxidation activity was recovered as soon as the free ammonia concentration was below the threshold level when dissolved oxygen concentration was not the limiting factor. Fluorescence in situ hybridization analysis of cryosectioned nitrite accumulating nitrifying biofilm showed that the β-subclass of Proteobacteria, where ammonia oxidizers belong, was distributed outside the biofilm whereas the α-subclass of Proteobacteria, where nitrite oxidizers belong, was found mainly in the inner part of the biofilm. It is likely that dissolved oxygen deficiency or limitation in the inner part of the nitrifying biofilm, where nitrite oxidizers exist, is responsible for the complete shut down of the nitrite oxidizers activity under the absence of free ammonia inhibition.

A protective effect of early pregnancy factor on experimental autoimmune encephalomyelitis induced in Lewis rats by inoculation with myelin basic protein

Experimental antoimmune encephalomyelitis (EAE) is an organ-specific autoimmune disease characterised by inflammation and demyelination of the central nervous system and is the best available animal model of multiple sclerosis (MS). Since previous studies have shown that EAE is less severe or is delayed in onset during pregnancy and that administration of the pregnancy hormone early pregnancy factor (EPF) down-regulates EAE, experiments in the present study were designed to explore further the role of EPF in EAE. By using the rosette inhibition test, the standard bioassay for EPF and, by semi-quantitative RT-PCR techniques, we have now shown that inflammatory cells from the spinal cord of rats with EAE can produce and secrete EPF, with production being greatest during recovery from disease. Administration of EPF to rats with EAE resulted in a significant increase in the expression of IL-4 and IL-10 mRNA and a significant decrease in IFN-gamma mRNA expression in spinal cord inflammatory cells. Encephalitogenic MBP-specific T cell lines were prepared from popliteal lymph nodes of rats with EAE. Proliferation assays using these cells demonstrated the ability of exogenous EPF to down-regulate the responses of T lymphocytes to MBP. (C) 2003 Elsevier B.V. All rights reserved.

An SPSS R-Menu for Ordinal Factor Analysis

Exploratory factor analysis is a widely used statistical technique in the social sciences. It attempts to identify underlying factors that explain the pattern of correlations within a set of observed variables. A statistical software package is needed to perform the calcula- tions. However, there are some limitations with popular statistical software packages, like SPSS. The R programming language is a free software package for statistical and graphical computing. It o ers many packages written by contributors from all over the world and programming resources that allow it to overcome the dialog limitations of SPSS. This paper o ers an SPSS dialog written in the R programming language with the help of some packages, so that researchers with little or no knowledge in programming, or those who are accustomed to making their calculations based on statistical dialogs, have more options when applying factor analysis to their data and hence can adopt a better approach when dealing with ordinal, Likert-type data.

Measuring fund performance using multi-factor models: evidence for the Portuguese market

This paper examines the performance of Portuguese equity funds investing in the domestic and in the European Union market, using several unconditional and conditional multi-factor models. In terms of overall performance, we find that National funds are neutral performers, while European Union funds under-perform the market significantly. These results do not seem to be a consequence of management fees. Overall, our findings are supportive of the robustness of conditional multi-factor models. In fact, Portuguese equity funds seem to be relatively more exposed to smallcaps and more value-oriented. Also, they present strong evidence of time-varying betas and, in the case of the European Union funds, of time-varying alphas too. Finally, in terms of market timing, our tests suggest that mutual fund managers in our sample do not exhibit any market timing abilities. Nevertheless, we find some evidence of timevarying conditional market timing abilities but only at the individual fund level.

Integration of Individualized Management Systems (MSs) as an Aggregating Factor of Sustainable Value for Organizations: An Overview Through a Review of the Literature

Nowadays, there exist various standards for individual management systems (MSs), at least, one for each stakeholder. New ones will be published. An integrated management system (IMS) aims to integrate some or all components of the business into one coherent and efficient MS. Maximizing integration is more and more a strategic priority in that it constitutes an opportunity to eliminate and/or reduce potential factors of destruction of value for the organizations and also to be more competitive and consequently promote its sustainable success. A preliminary investigation was conducted on a Portuguese industrial company which, over the years, has been adopting gradually, in whole or in part, individualized management system standards (MSSs). A research, through a questionnaire, was performed with the objective to develop, in a real business environment, an adequate and efficient IMS-QES (quality, environment, and safety) model and to potentiate for the future a generic IMS model to integrate other MSSs. The strategy and research methods have taken into consideration the case study. It was obtained a set of relevant conclusions resulting from the statistical analyses of the responses to the survey. Globally, the investigation results, by themselves, justified and prioritized the conception of a model of development of the IMS-QES and consequent definition and validation of a structure of an IMS-QES model, to be implemented at the small- and medium-sized enterprise (SME) where the investigation was conducted.

A Globalização como factor de Exclusão

Revista Lusófona de Ciências Sociais

A Conservação do Património Arquitectónico como factor de defesa do Ambiente

Revista Lusófona de Arquitectura e Educação

Confirmatory Factor Analysis of the Behavioural Regulation in Exercise Questionnaire – Portuguese Version

Exercise constitutes one of the pillars of a healthy lifestyle (USDHHS, 1996). Paradoxically, more than 40% of Europeans are sedentary (Eurobarometer 213, 2004), although some interventions, at both community and individual levels, have been established to improve this situation. Some of these interventions are based on Self-Determination Theory (SDT: Deci & Ryan, 1985), which state that more internalized types of behaviour regulation lead to feelings of selfdetermination in one’s chosen activities and, consequently, to greater likelihood of behavioural adherence. Today, SDT is one of the most popular approaches to the study of exercise, thus the cross-cultural validation of instruments that can measure its constructs is a necessary step to further advance in the study of exercise motivation.

Pressão, memorização e eficácia publicitária. Para além da repetição: a criatividade como factor potencial de eficácia da comunicação publicitária

Este artigo analisa a questão da eficácia publicitária num contexto de saturação. O reconhecimento da marca ou a recordação da publicidade associada à marca serão sempre, pelo menos, objectivos secundários de uma qualquer campanha publicitária. A eficácia surge assim associada inegavelmente à capacidade de memorização por parte do público-alvo das campanhas. Assim, parece consensual que as bases da eficácia publicitária são a memorização e a frequência publicitária no seu conjunto. Os modelos quantitativos existentes baseados em extensas bases de dados utilizados para estimar os resultados de eficácia utilizam sobretudo a relação cobertura/repetição, mas não chegam para saber qual a real eficácia do anúncio face aos objectivos junto de um determinado target. É possível aumentar a eficácia, através da criatividade, sem aumentar a pressão publicitária. Num contexto de saturação publicitária, o aumento da pressão publicitária não resultará certamente em maior eficácia. A resposta passará pelo poder da criatividade, desde logo nas estratégias do marketing e da comunicação, mas também das próprias mensagens publicitárias e na criatividade ao nível da utilização dos meios, sejam eles mais ou menos tradicionais.

The role of an illiquidity factor in the Portuguese stock market

This study examines the role of illiquidity (proxied by the proportion of zero returns) as an additional risk factor in asset pricing. We use Portuguese monthly data, covering the period between January 1988 and December 2008. We compute an illiquidity factor using the Fama and French [Fama, E. F., and K. R. French (1993), "Common risk factors in the returns on stocks and bonds", Journal of Financial Economics, Vol. 33, Nº. 1, pp. 3-56] procedure and analyze the performance of CAPM, Fama-French three-factor model and illiquidity-augmented versions of these models in explaining both the time-series and the cross-section of returns. Our results reveal that the effect of characteristic liquidity is subsumed by the models considered, but the risk of illiquidity is not priced in the Portuguese stock market.