Essai de Phytoclimatologie dynamique dans le nord du Portugal, et réflexion sur les climats mediterranéens portugais

A STUDY IN DYNAMIC PHYTOCLIMATOLOGY IN THE NORTH OF PORTUGAL AND THE QUESTION OF MEDITERRANEAN CLIMATES IN PORTUGAL - The climate-vegetation relation in the north of Portugal is studied in a new way. The dynamic continuity of the climate is revealed by the existence of botanical "continuums". The vegetation sampling was made along a continous NW-SE line transect, 185 km long, parallel to the strongest pluviometric gradient. Multivariate analysis and some of the applications of the information theory were used in the floristic study. In the climate study the spatial patterns of daily values of precipitation were analysed for a period of three years. This description was also done by means of multivariate analysis, including CCA for the aerological explanation. A "threshold of hydric satisfaction", around 1400mm of mean annual rainfall seems to determine the existence of an Atlantic vegetation, between the Alvão and Falperra mountains and the Ocean. This vegetation is homogeneous because it does not respond to the udometric variations above this level. To the east, the Atlantic vegetation rapidly dissapears. The comparison between daily precipitation regimes in the different stations and the dynamic interpretation of the differences bring some light to the discussion about the climate in the NW of the Iberian Peninsula: is it an Atlantic or a Mediterranean climate? In the maritime coast of Portugal these two influences mingle, as opposed to the sheltered interior provinces

Light with tunable non-Markovian phase imprint

We introduce a simple and flexible method to generate spatially non-Markovian light with tunable coherence properties in one and two dimensions. The unusual behavior of this light is demonstrated experimentally by probing the far field and recording its diffraction pattern after a double slit: In both cases we observe instead of a central intensity maximum a line or cross shaped dark region, whose width and profile depend on the non-Markovian coherence properties. Since these properties can be controlled and easily reproduced in experiment, the presented approach lends itself to serve as a testbed to gain a deeper understanding of non-Markovian processes

An Interactive Multimedia Instructional Program on Statistics: An Instance of Design-Based Research

Students’ fail or demonstrate slow progress in research methods and basic statistics courses if they have difficulty on identifying different types of variables. A web-based interactive multimedia instructional program for bringing them up to speed on this topic was designed and evaluated for effectiveness with 90 undergraduate college students. A significant effect of this program on students’ knowledge gain was determined. Careful consideration of the elements that made the teaching principles effective was taken by: (1) grounding the instructional design approach in cognitive psychology; and (2) collecting empirical data to validate the program features and instructional design methods used

Identification of differentially expressed genes in the heart precursor cells of the chick embryo

Genetic evidence has implicated several genes as being critical for heart development. However, the inducers of these genes as well as their targets and pathways they are involved with, remain largely unknown. Previous studies in the avian embryo showed that at HH4 Cerberus (cCer) transcripts are detected in the anterior endomesoderm including the heart precursor cells and later in the left lateral plate mesoderm. We have identified a promoter element of chick cCer able to drive EGFP expression in a population of cells that consistently exit from the anterior primitive streak region, from as early as stage HH3+, and that later will populate the heart. Using this promoter element as a tool allowed us to identify novel genes previously not known to potentially play a role in heart development. In order to identify and study genes expressed and involved in the correct development and differentiation of the vertebrate heart precursor cell (HPC) lineages, a differential screening using Affymetrix GeneChip system technologies was performed. Remarkably, this screening led to the identification of more than 700 transcripts differentially expressed in the heart forming regions (HFR). Bioinformatic tools allowed us to filter the large amount of data generated from this approach and to select a few transcripts for in vivo validation. Whole-mount in situ hybridization and sectioning of selected genes showed heart and vascular expression patterns for these transcripts during early chick development. We have developed an effective strategy to specifically identify genes that are differentially expressed in the HPC lineages. Within this set we have identified several genes that are expressed in the heart, blood and vascular lineages, which are likely to play a role in their development. These genes are potential candidates for future functional studies on early embryonic patterning.Fundação para a Ciência e a Tecnologia Ph.D., PD and BI fellowships; FCT research grants; IGC/FCG; IBB/CBME

Defeitos congénitos da glicosilação

Congenital disorders of glycosylation are a highly variable, rapidly expanding family of genetic diseases that result from defects in the synthesis of glycans. The vast majority of these monogenic diseases are inherited in an autosomal recessive way, but some types follow an autosomal dominant or X-linked inheritance. The present work aimed to review the state of the art of congenital disorders of glycosylation, including available therapeutic options, and present a simplified diagnostic approach to this group of diseases. Congenital disorders of glycosylation can be classified into four categories: N-linked glycosylation defects, O-linked glycosylation defects, combined glycosylation defects, and glycosphingolipid and glycosylphosphatidylinositol anchor synthesis defects. The phenotype may range from mild to severe, depending on disease severity. Clinical features include dysmorphic features, neurologic, dermatologic, cardiac, endocrine, immunologic, hematologic, gastrointestinal and liver involvement, and skeletal muscle abnormalities. As there is no universal or pathognomonic sign or symptom and no sensitive diagnostic test, it is of foremost importance to keep a high index of suspicion of these diseases. When a congenital disorder of glycosylation is suspected, the first step in screening is to perform serum transferrin isoelectric focusing. Molecular genetic testing is the most specific diagnostic test. Treatment is usually symptomatic, with specific treatment only available for some of these disorders. Since congenital defects of glycosylation may affect any organ at any age and have variable clinical presentation, they should be considered in the differential diagnosis of any patient with multiorgan involvement.info:eu-repo/semantics/publishedVersio

Sea bass (Dicentrarchus labrax) : a model organism for assessing multi-level responses to estrogenic chemicals in marine surface waters

Resumo apresentado sob poster ao 5th International Symposium of Fish Endocrinology, CAstellon, Spain, Setember 5-9, 2004.There is growing concern that aquatic wildlife in surface waters of the European Union is exposed to natural and man-made chemicals that have the ability to mimic estrogens and lead to reproductive dysfunction. Estrogenic responses in fish are the net result of complex chains of events involving the uptake, distribution and metabolism of test agents until they interact with their target sites. Typically these aspects cannot be modelled in short-term cell-based assays, only studies with vertebrates offer the opportunity to assess potential interactions of test compounds at higher organisational levels. The most widely studied biological response in fish to environmental estrogens is the production of vitellogenin (Vtg). However, few studies have attempted to link this endpoint with effects on xenobiotic biotransformation enzymes and genotoxic responses. This work is part of a study focusing on the combination effects of mixtures of estrogenic chemicals in marine and freshwater organisms. As test organism the sea bass (Dicentrarchus labrax) was selected, a common species in European marine systems. Juveniles were exposed under a flow-through system for 14 days to the natural estrogen 17ß-estradiol and ethynylestradiol. Actual chemical concentrations in the water-column were determined by gas chromatography with ion trap detection. Effects at subcellular level were analysed using Vtg as a reference endpoint [1]. Its relevance is evaluated by further investigations on liver 7-ethoxyresorufin-O-deethylase (EROD) activity and erythrocytic nuclear abnormalities [2]. These measurements were integrated with organism level endpoints (i.e. condition factor, hepatossomatic index) to provide evidence for cause-effect of estrogenic contamination. The general suitability of the sea bass as a model organism for the screening of estrogenic chemicals in the marine environment is discussed.Comissão Europeia (CE) - ACE, EVK1-CT-2001-100

Monitoring biotechnological processes through quantitative image analysis: application to 2-phenylethanol production by Yarrowia lipolytica

Available online 20 March 2023Quantitative image analysis (QIA) is a simple and automated tool for process monitoring that, when combined with chemometric techniques, enables the association of changes in microbiota morphology to various operational parameters. To that effect, principal component analysis, multilinear regression, and ordinary least squares methods were applied to the obtained dataset of the biotransformation conditions for Y. lipolytica through the monitor of yeast morphology, substrates (glycerol, L-phenylalanine - L-Phe) consumption and metabolites (2-phenylethanol 2-PE) production was developed. Glycerol and L-Phe were successfully monitored by the proposed approach, though with a lower monitoring ability for 2-PE, and mostly related to yeast and cluster size and proportion, yeasts contents and cluster morphology. The chemometric approach also allowed to identify significant morphological modifications related with the change in the stirring speed in the experiments at 600rpm, 600/400rpm (600rpm for 24h, and 400rpm until the end of the experiment) and in pH from 5.5 to 7.5. This work demonstrated, for the first time, that QIA combined with chemometric analysis can be considered a valuable tool to monitor biotechnological processes, namely the 2-PE production by Y. lipolytica, by analyzing yeast and cluster morphology.info:eu-repo/semantics/publishedVersio

Design e validação de um modelo de reabilitação com implantes curtos

Objectives: This research intended to develop and validate a digital model that could be used to study the stresses and strains created in the different components involved in oral fixed rehabilitations with short implants. The validated model was then used to simulate a clinical- like situation. Methods: A digital model was created considering the posterior areas of the mandible. Its materialization obtained ten specimens of the experimental prototype. Seven of them were static compressive tested until failure and, for the other three, the tests were progressively interrupted, to allow the establishment of a damage sequence. On the numerical model a finite element analysis was performed with Abaqus software, under similar conditions to the experimental situation. Results: The stress pattern on the FEA and the failure location on the static test were similar. The sequence in which each part reached the yield strength was the same as that observed on the interrupted static test (resin, prosthetic framework, implants and implant screws, in this order). Due to these results, the model was considered valid. A clinical-like simulation with the validated model showed that buccal cortical bone, around the implants platform, is the weakest part of such a rehabilitation. Conclusions: This research allowed the development and validation of a computer-aided design model that can be used to study an oral fixed rehabilitation supported by short implants. For clinical purposes, it is important to refer that the highest stress and strain values were found on the cortical bone around the buccal aspect of the implants.Objetivos: O objetivo desta investigação foi o desenvolvimento e validação experimental de um modelo digital, que permita o estudo das tensões e deformações geradas nos diferentes componentes de uma reabilitação oral fixa sobre implantes curtos. O modelo obtido foi então usado para simular uma situação clinica. Métodos: Um modelo numérico foi criado considerando a região posterior da mandibula. A sua materialização permitiu obter dez amostras do protótipo experimental. Sete delas foram sujeitas a ensaios estáticos de compressão até à falência. Nas restantes três, os ensaios foram interrompidos com forças gradualmente crescentes, estabelecendo a sequência pela qual os componentes se deformaram. O modelo numérico foi também sujeito a uma simulação com elementos finitos, usando o software Abaqus, em condições semelhantes à simulação experimental. Resultados: O padrão de tensões obtido no modelo numérico foi similar à localização das fraturas no modelo experimental. A sequência segundo a qual a tensão de cedência foi alcançada em cada parte do modelo numérico foi a mesma encontrada quando o ensaio estático se interrompeu (por esta ordem: resina, prótese, implantes e parafusos). Estes resultados permitiram considerar o modelo válido. A simulação de uma situação clínica, com o modelo validado, revelou que o osso cortical, em vestibular da plataforma dos implantes, é a região mais débil da reabilitação. Conclusões: Esta investigação permitiu o desenvolvimento e a validação de um modelo que permite o estudo de reabilitações fixas sobre implantes curtos. Clinicamente é importante realçar que o osso cortical é a zona que apresenta tensões e deformações mais elevadas. (Rev Port Estomatol Med Dent Cir Maxilofac. 2017;58(2):79-90)info:eu-repo/semantics/publishedVersio

Sea bass (Dicentrarchus labrax) : a model organism for the screening of estrogenic chemicals in marine surface waters?

Society of Environmental Toxicology and Chemistry - SETAC Europe 14th Annual Meeting, Prague, Czech Republic, April 2004.There is growing concern that aquatic wildlife in surface waters of the European Union is exposed to natural and man-made chemicals that have the ability to mimic estrogens and lead to reproductive dysfunction. Estrogenic responses in fish are the net result of complex chains of events involving the uptake, distribution and metabolism of test agents until they interact with their target sites. Typically these aspects cannot be modelled in short-term cell-based assays, only studies with vertebrates offer the opportunity to assess potential interactions of test compounds at higher organisational levels. However, studies with endocrine disrupting chemicals have been performed mainly with freshwater organisms. The sensitivity of a marine fish species to different estrogenic chemicals was investigated under chronic exposure conditions. This work is part of a study focusing on the combination effects of mixtures of estrogenic chemicals in marine and freshwater organisms (ACE, EVK1-CT-2001-100). As test organism the sea bass (Dicentrarchus labrax) was selected, a common species in European marine systems. Juveniles were exposed under a flow-through system for 14 days for a set of reference chemicals (17Ã -estradiol, ethynylestradiol, nonylphenol, octylphenol, bisphenol A). Effects at subcellular level were analysed using vitellogenesis as endpoint. Its relevance is evaluated by further investigations about the individual fitness (condition factor, hepatossomatic index), as well as the liver cytochrome P450 activity. The general suitability of the sea bass as a model organism for the screening of estrogenic chemicals in the marine environment is discussed.Comissãoo Europeia (CE) - ACE, EVK1-CT-2001-100