Educação, conflito e convivência democrática

Após uma caracterização sucinta da actual condição pós-moderna, serão desenvolvidas algumas questões que, pela sua relevância actual no campo da educação, merecem ser revisitadas de modo crítico, nomeadamente, e num primeiro momento, a escola, o conflito e a convivência. Num segundo momento, apontar-se-ão algumas características da escola que fazem dela uma organização com alguma perversidade, hipocrisia e irracionalidade. O último aspecto a ser tratado irá compreender a escola como organização comunicacional ou organização convivencial, onde os conceitos de disciplina, violência, conflito e convivência assumem um sentido mais profundamente democrático.After a succinct characterization of the current postmodern condition, some questions might be developed, because of its current relevance in the education field, they must to be reviewed in a critical way, namely, and firstly, the school, the conflict and the conviviality. Secondly, this article underlines some school’s characteristics that turns it into an organization with a little perversity, hypocrisy and irrationality. The last aspect to be treated is the understanding of the school as a communicative or convivial organization, in which the concepts of discipline, violence, conflict and conviviality assume a more democratic orientation.Enseguida a una caracterización sucinta de la actual condición pos-moderna, serán desarrolladas algunas cuestiones que, por su relevancia actual en el campo de la educación, merecen ser visitadas de modo crítico, nombradamente, y en primero momento, la escuela, el conflicto y la convivencia. En segundo momento, se apuntarán algunas características de la escuela que la hacen una organización con alguna perversidad, hipocresía e irracionalidad. El último aspecto a ser tratado irá comprender la escuela como organización de comunicación u organización de convivencia, donde los conceptos de disciplina, violencia, conflicto e convivencia asumen un sentido más profundamente democrático.(undefined

Cloning, characterisation and tissue distribution of an aquaporin-3 cDNA from fish (Sparus aurata)

The major intrinsic protein (MIP) family consists of several transmembrane channel proteins specific for water and neutral solutes. All proteins belonging to the MIP family evolved from two divergent bacterial paralogues, one giving rise to the CHIP group, functionally characterised as water channels and the other to the GLP group, specialised in glycerol transport. Three forms of MIP proteins belonging to the GLP group have been identified in mammals: aquaporin-3 (AQP-3), aquaporin-7 (AQP-7) and aquaporin-9 (AQP-9). We have recently cloned and characterised a GLP cDNA from the marine teleost sea bream (Sparus aurata) and studied its tissue distribution. Phylogenetic analysis revealed it was most like AQP-3 and further studies are now underway to determine its role in hydromineral balance.C.R.A.S. - FCT grant; PRAXIS XXI/BPD/22040/99; J.C.R.C. - FCT grant PRAXIS XXI/BD/19925/99; J.F. - EU grant; FAIR-CT96-1742. This work was funded by PRAXIS XXI/2/2.1/211.info:eu-repo/semantics/publishedVersio

A fish scale in vitro bioassay to screen for endocrine disrupting compounds

A wide range of natural and anthropogenic compounds are accumulating in the aquatic environment, many of which can interact with and disrupt the endocrine system. Estrogenic endocrine disruptors (EDCs) are a particular problem with impact on humans, ecosystems and wildlife and are particularly relevant in aquatic organisms like fish that may experience life-long exposures. The effects of EDCs in fish have mainly been assessed using reproductive endpoints and in vivo animal experiments. We propose that using other potential endpoints, such as the effect of estrogens on mineralized tissue, would allow development of a simple non invasive assay using scales. Fish scales are mineralized tissues that express both membrane and nuclear estrogen receptors, and are targets for natural estrogens and EDCs. The in vitro bioassay optimized in this work includes sampling of fish scales, incubation in culture media containing the tested compounds and measurement of enzymatic activities related to calcium turnover (TRAP, tartrate-resistant acid phosphatase and ALP, alkaline phosphatase). Several variables were optimized including culture media, compounds concentrations and incubation conditions (e.g. temperature, time), using both sea bass (Dicentrarchus labrax) and tilapia (Oreochromis mossambicus) scales. Significant effects of E2 and EDCs were detected, including both rapid (30 minutes) or slow (1day) changes in scale TRAP or ALP activities, but the responses were of low magnitude and varied with the individual, age, time of year, species and culture conditions. The in vitro fish scale assay is a promising non-invasive screening tool for E2 and EDCs effects, complying with the 3Rs of animal welfare. However, current technical limitations are its limited sensitivity for some parameters eg. TRAP/ALP activity and alternative, sensitive, robust and easy to measure endpoints are under investigation.info:eu-repo/semantics/publishedVersio

In vitro screening for estrogenic endocrine disrupting compounds using Mozambique tilapia and sea bass scales

A wide range of estrogenic endocrine disruptors (EDCs) are accumulating in the environment and may disrupt the physiology of aquatic organisms. The effects of EDCs on fish have mainly been assessed using reproductive endpoints and in vivo animal experiments. We used a simple non-invasive assay to evaluate the impact of estrogens and EDCs on sea bass (Dicentrarchus labrax) and tilapia (Oreochromis mossambicus) scales. These were exposed to estradiol (E2), two phytoestrogens and six anthropogenic estrogenic/anti-estrogenic EDCs and activities of enzymes related to mineralized tissue turnover (TRAP, tartrate-resistant acid phosphatase and ALP, alkaline phosphatase) were measured. Semi-quantitative RT-PCR detected the expression of both membrane and nuclear estrogen receptors in the scales of both species, confirming scales as a target for E2 and EDCs through different mechanisms. Changes in TRAP or ALP activities after 30 minute and 24 h exposure were detected in sea bass and tilapia scales treated with E2 and three EDCs, although compound-, time- and dose-specific responses were observed for the two species. These results support again that the mineralized tissue turnover of fish is regulated by estrogens and reveals that the scales are a mineralized estrogen-responsive tissue that may be affected by some EDCs. The significance of these effects for whole animal physiology needs to be further explored. The in vitro fish scale bioassay is a promising non-invasive screening tool for E2 and EDCs effects, although the low sensitivity of TRAP/ALP quantification limits their utility and indicates that alternative endpoints are required

The effects of di-n-butyl phthalate and 4-tert-octylphenol in osteoclastic and osteoblastic activities in teleost fish scales

Di-n-butyl phtalate (DBP) and 4-tert-octylphenol (OP) are environmental pollutants with estrogenic activity that have been shown to have endocrine disruptive actions in reproduction of several fish species. However, their impact in bone and scale metabolism, which are estrogen-responsive tissues, remains unknown. In this study, we evaluated the impact of these compounds on mineral metabolism in fish scales that, like bone, are a dynamic tissue maintained by continuous cycles of formation and resorption mediated, respectively, by osteoblasts (OSB) and osteoclasts (OSC). Using an in vitro bioassay, Atlantic sea bass (a marine species) and Mozambique tilapia (a freshwater species) scales were incubated with a range of concentrations of OP and DBP in culture media for a short (30 minutes) or long (24 hours) incubation time. Effects on the activity of tartrate resistant acid phosphatase (TRAP) and alkaline phosphatase (ALP), markers for OSC and OSB activities, respectively, were assessed using a colorimetric enzymatic assay. DBP (10-6 M) affected TRAP activity in both species. While in sea bass, TRAP activity increased with DBP after 30 min incubation but was unaffected after 24 h, in tilapia no alterations were observed at the short term but a significant decrease was observed after 24 h incubation with this compound. None of the tested concentrations (10-10 to 10-6 M) affected ALP activity in both species. On the contrary, OP effects were only observed on the activity of ALP, which was significantly decreased after a 24 h incubation with 10-8 M of OP in the scales of both species. These results suggest that the exposure to these compounds may have disruptive effects on the metabolism of mineralized tissues in both marine and freshwater species. Future studies will investigate the mechanisms involved in these responses and the consequences for fish health.Foundation for Science and Technology of Portugal (FCT), through projects PTDC/AAG-GLO/4003/2012 and PEst-C/MAR/LA0015/2011 and fellowship to PP (SFRH/BPD/84033/2012).info:eu-repo/semantics/publishedVersio

Modelização do sistema de manutenção do motor F100-PW-220E da Força Aérea Portuguesa

Mestrado em Gestão e Estratégia Industrialinfo:eu-repo/semantics/publishedVersio

Tissue responsiveness to estradiol and genistein in the sea bass liver and scale

As in mammals, estrogens in fish are essential for reproduction but also important regulators of mineral homeostasis. Fish scales are a non-conventional target tissue responsive to estradiol and constitute a good model to study mineralized tissues effects and mechanisms of action of estrogenic compounds, including phytoestrogens. The responsiveness to estradiol and the phytoestrogen genistein, was compared between the scales and the liver, a classical estrogenic target, in sea bass (Dicentrarchus labrax). Injection with estradiol and genistein significantly increased circulating vitellogenin (for both compounds) and mineral levels (estradiol only) and genistein also significantly increased scale enzymatic activities suggesting it increased mineral turnover. The repertoire, abundance and estrogenic regulation of nuclear estrogen receptors (ESR1, 2a and 2b) and membrane G-protein receptors (GPER and GPER-like) were different between liver and scales, which presumably explains the tissue-specific changes detected in estrogen-responsive gene expression. In scales changes in gene expression mainly consisted of small rapid increases, while in liver strong, sustained increases/decreases in gene expression occurred. Similar but not overlapping gene expression changes were observed in response to both estradiol and genistein. This study demonstrates for the first time the expression of membrane estrogen receptors in scales and that estrogens and phytoestrogens, to which fish may be exposed in the wild or in aquaculture, both affect liver and mineralized tissues in a tissue-specific manner. (C) 2015 Elsevier Ltd. All rights reserved

Efeitos do treino de força sobre a performance de lançamento em jogadores infantis de pólo aquático

Objectivos: O objectivo deste estudo foi determinar os efeitos de dois programas de treino de força com a mesma carga de trabalho (i.e., o mesmo impulso mecânico) sobre a performance de lançamento em jogadores infantis de pólo aquático. Hipóteses: Ambos os grupos melhorariam a velocidade de lançamento com a bola de pólo aquático e com as bolas medicinais, utilizando a mesma carga de trabalho para ambas as formas de treino. Uma diferença substancial entre os grupos indicaria a influência da especificidade dos conteúdos de treino. Métodos: Participaram neste estudo jogadores infantis de pólo aquático (n = 16, idade 14,3 ± 0,8 anos, peso 64,2 ± 9,8 kg, altura 169,9 ± 6,7 cm e envergadura 174,3 ± 6,1 cm) divididos em dois grupos homogeneamente indexados a um tipo de treino específico. O programa de treino foi composto por 2 sessões semanais durante 8 semanas consecutivas com a mesma carga de trabalho (i.e., o mesmo impulso mecânico). Um grupo (G1) realizou 3 séries de 6 repetições com a bola medicinal de 3kg, enquanto que um segundo (G2) completou 1 série de 9 repetições com a bola de 3kg e mais 3 séries de 14 repetições com a bola oficial de PA. O protocolo de treinos respeitou ainda as seguintes regras: (1) os sujeitos realizavam 1 lançamento de 15 em 15 segundos; (2) em todas as repetições os jogadores de PA tiveram de aplicar a máxima velocidade respeitando uma pausa de aproximadamente 2 minutos entre cada série para evitar o aparecimento de fadiga. Resultados: Relativamente à velocidade de lançamento, verificou-se um aumento significativo na velocidade de lançamento entre o pré-treino (primeiro momento de avaliação) e o pós-treino (segundo momento de avaliação), em ambos os grupos (p˂0.05), excepto para o G1 com a bola de 1 kg. Contudo, no segundo momento de avaliação (pós-treino), não se verificou diferenças significativas na velocidade de lançamento das diferentes bolas entre os dois grupos de treino (p>0.05). Conclusão: Concluiu-se que os dois programas de treino aplicados foram eficazes no aumento da velocidade de lançamento, embora não se tenha podido observar diferenças significativas entre os dois programas de treino. Este estudo demonstrou ainda que um trabalho simples com bolas medicinais pode ser altamente eficaz e de fácil exequibilidade ao nível do escalão de infantis de pólo aquático.Purpose: The purpose of this study was to determine the effects of two different strength programs with the same effort workload (eg. the same mechanical push) Hypothesis: Both groups would improve the throwing velocity with the water polo ball and the medicine balls, if using the same work strength in both training methods. A significant difference between the groups would indicate the influence of the specificity of the training contents. Methods: The water polo children players who took part in this study (n=16, age 14,3 ± 10,8 yr, weight 64,2 ± 9,8 kg, height 169,9 ± 6,7cm and arm span 174,3 ± 6,1cm) were divided in two groups equally following a specific training which was composed by two weekly sessions during eight weeks of equal workload. A group (G1) has performed three series of six reps with a three kg medicinal ball, while another group (G2) has completed one series of nine reps with the same 3kg ball, plus three more series of fourteen reps with the official PA ball. The training protocol has also respected the following rules: (1) the participants had to perform a throwing within fifteen seconds; (2) on all the reps, the PA players had to apply the maximum speed respecting an approximately two minutes pause between each series in order to avoid tiredness. Results: Regarding the throwing velocity/speed, there was a significant increase between the before-training (first evaluation moment) and the after-training (second evaluation moment) in both groups, except for the G1 group with the one kg ball. However, on the second evaluation moment (after-training), there were no significant differences between the two training groups on the throwing performance of the different balls (p>0.05). Conclusion: We reached the conclusion that both training programs applied were effective on the increase of the throwing velocity/speed, even though there was no possibility to observe significant differences between both training programs. This study has shown that a simple work with medicinal balls can be highly effective and of easy workability on the level of water polo children players

Proteome dataset of sea bass (Dicentrarchus labrax) skin-scales exposed to fluoxetine and estradiol

Contamination of aquatic ecosystems with anthropogenic pollutants, including pharmaceutical drugs, is a major concern worldwide. Aquatic organisms such as fish are particularly at risk of exposure to pollutants. The surface of fish is the first point of contact with pollutants, but few studies have considered the impact of pollutants on the skin-scale barrier. The present proteome data are the basis of the findings discussed in the associated research article "Proteomics of sea bass skin-scales exposed to the emerging pollutant fluoxetine compared to estradiol" [1]. Juvenile sea bass were exposed by intraperitoneal injections to: a) the antidepressant fluoxetine (FLX), a widely prescribed psychotropic drug and an emerging pollutant; b) the natural estrogen 17 beta-estradiol (E2) and c) the vehicle, coconut oil (control). The scale proteome of fish exposed to these compounds for 5 days was analysed using quantitative label-free proteomics technology SWATH-MS (sequential windowed data-independent a cquisition of the total high-resolution-mass spectra). The proteome data generated was submitted to the ProteomeXchange Consortium via the PRIDE partner repository with the dataset identifier PXD020983. LC-MS data from pooled protein extracts from the scales of all experimental groups was acquired using information-dependent acquisition (IDA) and 1,254 proteins were identified by searching against the sea bass genome database. 715 proteins were quantified by SWATH acquisition, and 213 proteins had modified levels (p < 0.05) between the E2- or FLX-exposed fish compared to the control. The main biological processes and KEGG pathways affected by E2 or FLX treatments were identified using Cytoscape/ClueGO enrichment analyses. (c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)info:eu-repo/semantics/publishedVersio

Efeitos de fitoestrogénios no metabolismo mineral em escamas de robalo e de tilápia moçambicana

O rápido desenvolvimento da aquacultura nas últimas décadas fez aumentar a procura por fontes proteicas adequadas para incluir nas rações dos peixes. A soja tem sido muito utilizada com fonte proteica de origem vegetal mas é particularmente rica em fitoestrogénios, incluindo a genisteína (GEN) e a daidzeína (DAI), que são as principais isoflavonas presentes na soja. Os peixes podem estar expostos aos fitoestrogénios no ambiente ou através das dietas que os contêm, como é o caso da soja. Estes compostos podem ter atividades estrogénicas e efeitos disruptivos na reprodução mas o seu impacto nos tecidos mineralizados continua a ser desconhecido. As escamas de peixe são um tecido mineralizado que, tal como o osso de mamíferos, é mantido por ciclos de formação e reabsorção, mediado por osteoblastos (OSB) e osteoclastos (OSC), respetivamente. As escamas são um tecido responsivo aos estrogénios e expressam os recetores de estrogénio nucleares (ERs). As atividades das enzimas fosfatase alcalina (ALP) e fosfatase ácida resistente ao tartrato (TRAP) são usadas como marcadores das atividades dos OSB e OSC, respetivamente, e são modificadas pelo estradiol (E2) nas escamas de várias espécies de peixe. Usando um ensaio in vitro, investigámos o possível impacto da exposição a GEN e a DAI no metabolismo mineral em escamas. O efeito destes compostos foi avaliado através da determinação das atividades de TRAP e ALP em escamas de robalo (Dicentrarchus labrax), uma espécie marinha, e de tilápia moçambicana (Oreochromis mossambicus), mantida em água salgada (AS) e em água doce (AD).info:eu-repo/semantics/publishedVersio