Aplicação da interferometria holografia subaquática para análise de estruturas

Pretende-se com este trabalho estudar a aplicação das técnicas de interferometria holográfica à análise estrutural em ambiente subaquático. Estas técnicas estão hoje bem divulgadas e com aplicações em diversas áreas. No entanto, a sua aplicação em ambientes subaquáticos, apresenta alguns desafios. Neste trabalho estuda-se a aplicação de duas técnicas, ESPI e holografia digital, comparando-as e apresentando vantagens e desvantagens de cada uma delas. Faz-se um breve estudo sobre a influência das instabilidades resultantes da turbulência das águas e da presença de partículas em suspensão bem como possíveis soluções para minimizar estes problemas

Vascular and apoptotic changes in the placode of myelomeningocele mice during the final stages of in utero development

JOAQUIM L. REIS, M.D., PH.D.,1,2 JORGE CORREIA-PINTO, M.D., PH.D.,3,4 MARIANA P. MONTEIRO, M.D., PH.D.,1 MADALENA COSTA, B.SC.,1 AND GROVER M. HUTCHINS, M.D.5 1Department of Anatomy, Abel Salazar Institute for the Biomedical Sciences and Unit for Multidisciplinary Biomedical Research, University of Porto; 2Department of Neurosurgery, Santo António General Hospital; 4Department of Pediatric Surgery, São João Hospital, Porto; 3Life and Health Sciences Research Institute, School of Health Sciences, University of Minho, Braga, Portugal; and 5Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland Object. Myelomeningocele (MMC) is a primary neurulation defect that is associated with devastating neurological disabilities in affected newborns. To better characterize the in utero neurodegenerative process of MMC, the authors investigated the changes in vascular organization, apoptosis, and the presence of inflammatory cells during gestation by using a mutant mouse model of MMC. Methods. The curly tail/loop tail (ct/lp) mutant mouse model of MMC was chosen to obtain fetuses at different stages of gestation. Mouse fetuses harboring MMC were harvested by caesarean section at embryonic Days 14.5, 16.5, and 18.5 (complete mouse gestation at 19 days, 6 mice/group); littermate fetuses with the same gestational age but without an MMC were used as controls. Samples of the MMC placode or normal spinal cord were stained for immunocytochemical labeling with caveolin antibody (endothelium marker) and activated caspase-3 antibody (apoptosis marker). Samples were morphometrically analyzed with a computer-assisted image analyzer. Results. The MMC mice presented with an increase in vascular density from embryonic Days 16.5–18.5 and an enhanced number of apoptotic cells at embryonic Day 18.5, compared with controls. There were scarce signals of an inflammatory reaction in the MMC placode, as a few infiltrating neutrophils were seen only at embryonic Day 18.5. Conclusions. Fetal placodes in MMC mice showed evidence of increased vascular density since embryonic Day 16.5 and increased apoptosis at embryonic Day 18.5. These new data support the view that in utero changes of the MMC placode, occurring during the last stages of gestation, contribute to the neuropathological manifestations in fullterm newborns with MMC. (DOI: 10.3171/PED/2008/2/8/150

Cytotoxicity and antitumoral activity of dichloromethane extract and its fractions from Pothomorphe umbellata

The cytotoxicity of the dichloromethane crude extract (DCE), obtained from the aerial parts of Pothomorphe umbellata (L.) Miq (Piperaceae), was evaluated against nine human cancer cell lines (MCF-7, NCI-ADR/RES, OVCAR-3, PC-3, HT-29, NCI-H460, 786-O, UACC-62, K-562). The DCE presented antiproliferative activity with good potency against all cell lines at low concentrations (between 4.0 and 9.5 µg/mL) and with selectivity (1.55 µg/mL) for the leukemia cell line (K-652). DCE (100, 200, 300 and 400 mg/kg, ip) was also evaluated in the Ehrlich ascites tumor model. Both the survival number and the life span of the animals that died increased by at least 45 and 50%, respectively (8 animals per group), demonstrating P. umbellata extract potential anticancer activity. The results of the in vivo antitumor activity prompted the fractionation of the crude extract. The crude extract was submitted to dry column chromatography with dichloromethane-methanol (99:1). The column effluent fractions were extracted with methanol, dried under vacuum yielding fractions FR1 (less polar), FR2 (medium polarity), and FR3 (polar), which were analyzed for their growth inhibition or cytotoxic properties by a 48-h sulforhodamine B cell viability assay by measuring the total protein content. FR1 demonstrated high potency and cytotoxicity, a result compatible with the high toxicity of oxalic acid; FR2, containing 4-nerolidylcathecol, presented the lowest cytotoxic activity compared to the other two fractions but with selectivity for prostate cancer cell line; FR3, containing a mixture of steroids described in the literature as possessing various biological activities, also presented potent anticancer in vitro activity. These results suggest that P. umbellata DCE in vivo antitumor activity may be a consequence of the activity of different active principles.41141

Can a restocking event with European (glass) eels cause early changes in local biological communities and its ecological status?

In an attempt to assist the recovery of the panmictic population of the European eel, declining since the late 1980s, the restocking of areas with low or no natural recruitment has been one of the measures adopted to reverse this trend. However, the main focus in several monitoring programmes for these actions, has been in the best interest of its viability and cost/benefit relationships and, for that, the condition of the released stocks has been the main concern. Yet, so far, no studies have assessed the potential ecological impacts that restocking might have on other biological communities. This pioneer pilot study aimed to evaluate the early ecological impact of a restocking event on other biological communities, considering inter-specific competition (other fish species) and feeding impact (macroinvertebrates).The reference condition of the biological communities of an inland tributary of the Mondego river, the River Ceira, was determined in three sites inaccessible to the natural recruitment of eels, followed by a post-stocking assessment. The results showed no significant changes in the fish assemblages in restocked areas, contrary to the macroinvertebrate community. However, the ecological status for the macroinvertebrate community showed no deleterious effects, with the results suggesting exactly the opposite. This may be related to the low density of the restocked eels and factors influencing the local trophic web. This study confirms the suitability of the habitat for restocking with glass eels, during its early stages, without disrupting the local ecological status, using densities close to those of natural recruitment

Antarctic ice sheet fertilises the Southern Ocean

Open access journalSouthern Ocean (SO) marine primary productivity (PP) is strongly influenced by the availability of iron in surface waters, which is thought to exert a significant control upon atmospheric CO2 concentrations on glacial/interglacial timescales. The zone bordering the Antarctic Ice Sheet exhibits high PP and seasonal plankton blooms in response to light and variations in iron availability. The sources of iron stimulating elevated SO PP are in debate. Established contributors include dust, coastal sediments/upwelling, icebergs and sea ice. Subglacial meltwater exported at the ice margin is a more recent suggestion, arising from intense iron cycling beneath the ice sheet. Icebergs and subglacial meltwater may supply a large amount of bioavailable iron to the SO, estimated in this study at 0.07-0.2 Tg yr-1. Here we apply the MIT global ocean model (Follows et al., 2007) to determine the potential impact of this level of iron export from the ice sheet upon SO PP. The export of iron from the ice sheet raises modelled SO PP by up to 40%, and provides one plausible explanation for seasonally very high in situ measurements of PP in the near-coastal zone. The impact on SO PP is greatest in coastal regions, which are also areas of high measured marine PP. These results suggest that the export of Antarctic runoff and icebergs may have an important impact on SO PP and should be included in future biogeochemical modelling.Philip Leverhulme PrizeLeverhulme Research FellowshipLeverhulme TrustRoyal Society Fellowship7th European Community Framework Programme - Marie Curie Intra European FellowshipNatural Environment Research Council (NERC

A lapa do Bugio

A jazida pré-histórica do Bugio constitui uma das mais importantes grutas sepulcrais da faixa estremenha. Encontrava-se intacta à data das primeiras escavações, realizadas em 1957 e 1958. Vicissitudes várias que motivaram a dissolução da primeira equipa e favoreceram diversas depredações, entretanto realizadas, impediram que, antes do recomeço dos trabalhos, em 1966, mesmo dos materiais recuperados, se pudessem extrair todas as informações neles potencialmente contidas. Foi possível, a partir do estudo exaustivo do espólio conservado no Museu de Sesimbra e no recolhido nas escavações de 1966, estabelecer a seguinte sucessão cronológica-cultural: Primeira ocupação - corresponde talvez à ocupação mais importante, integrável no Neolítico recente-final estremenho. Estreitas analogias com o "horizonte dolménico" identificado na vizinha Lapa do Fumo e datado pelo rádio-carbono de 3090 ± 160 a. C. (SERRÃO,1978). A datação realizada no Bugio deu 2800 ± 45 a.C. Segunda ocupação- corresponde muito provavelmente a momento inicial (ou pleno) do Calcolítico, definido pela presença de raros produtos, como o recipiente de osso recolhido na sep. 7 e "ídolos" de calcário, de osso e marfim. Terceira ocupação - Calcolítico final, campaniforme - representada pelos Grupos de Palmela e Inciso. Trata-se da ocupação menos importante, excessivamente valorizada em trabalhos anteriores, talvez pela grande dispersão de fragmentos cerâmicos que não ultrapassam, contudo, nove recipientes (alguns deles representados por apenas um fragmento): taças em calote - (I), de bordo espessado - (I), de tipo Palmela - (I), caçoilas acampanadas - (2), e vasos campaniformes - (2), além de dois recipientes de tipologia mal definida.Le gisement préhistorique de Bugio est l 'une des plus importantes grottes sépulcrales du littoral de l'Estrémadure. Elle a été trouvée intacte lors des premières fouilles, réalisées en 1957 et 1958. Diverses vicissitudes, qui devaient aboutir à la dissolution de la première équipe de fouilleurs et favoriser le pillage du site, empêchèrent la difusion de toute information avant la reprise des travaux en 1966, même sur le matériel récupéré. A partir de l' étude exhaustive du mobilier conservé au Musée de Sesimbra et de celui qui a été découvert en 1966, on a pu établir les niveaux chronologiques suivants: Première occupation, peut-être la plus importante, s'intégrant dans le Néolithique récent et final de l'Estrémadure, présentant d' étroites analogies avec "l'horizon dolménique" identifié sur le site voisin de Lapa do Fumo, daté de 3090 ± 160 a.C. par radio-carbone (SERRÃO, 1978). La datation obtenue à Bugio est de 2800 ± 45 a.C.. Seconde occupation, correspondant très probablement à la phase initiale ou médiane du Chalcolithique, définie par de rares productions, comme le récipient en os recueilli dans la sépulture 7 et les "idoles" en calcaire, en os et en ivoire. Troisième occupation (Chalcolithique final, Campaniforme) représentée par les Groupes de Palmela et incisé. Il s'agit d'une occupation moins importante, surévaluée dans les travaux antérieurs, peut-être en raison de la grande dispersion des fragments de céramiques qui ne correspondaient, cependant, qu'à neuf récipients: coupes en calotte (1 ), coupes au bord épais (1), coupes de type de Palmela (1), casseroles en forme de cloche (2), vases campaniformes (2) et deux récipients à la typologie mal définie

Control algorithms based on the active and non-active currents for a UPQC without series transformers

This study presents control algorithms for a new unified power quality conditioner (UPQC) without the series transformers that are frequently used to make the insertion of the series converter of the UPQC between the power supply and the load. The behaviour of the proposed UPQC is evaluated in presence of voltage imbalances, as well as under non-sinusoidal voltage-and current conditions. The presented algorithms derive from the concepts involving the active and non-active currents, together with a phase-locked-loop circuit. Based on these real-time algorithms, and considering the proposed hardware topology, the UPQC is able to compensate the harmonic components of the voltages and currents, correct the power factor, and keep the load voltages regulated, all of this in a dynamic way, responding instantaneously to changes in the loads or in the electrical power system. The control algorithms were distributed in a two-DSP digital control architecture, without any communication between them. Consequently, can be increased the sampling frequency of the acquired voltages and currents and improve the UPQC performance. Furthermore, some constraints of the proposed UPQC are evidenced, particularly when the main voltages are imbalanced. Simulation and experimental results are presented to verify the UPQC performance under transient and steady state conditions.info:eu-repo/semantics/publishedVersio

Fast building – increasing the geometrical freedom of textile reinforced concrete systems

Apresentação efetuada na 9th International Conference Mechanics and Materials in Design - Theory, Experiments and Applications in Engineering (M2D2021), no Funchal, Portugal, 2022[Excerpt] Introduction Textile technology is highly innovative, and several techniques are already being used to act as building parts for fast building, interior design, architectural details and offshore structures. However, such potential still fails when complex geometrical structures or multifunctionality are required.Fundação para a Ciência e a Tecnologia - grant SFRH/BD/144201/2019European Regional Development Fund (FEDER), Operational Program for Competitiveness Factors (COMPETE) POCI-01-0247-312 FEDER-03973

Research of the optical communications groups at University of Aveiro and Institute of Telecommunications - Aveiro Pole

This paper summarizes the research activities of the optical communications group at University of Aveiro and Institute of Telecommunications – Aveiro pole. Several activities like clock recovery systems, both electrical and all optical, electrical equalizers for very high bit rate DST systems, post-detection filters for multigigabit optical receivers, soliton systems, simulation work on WDM, DST, EDFA and short pulse generation for high bit rate systems are presented