Browsing by Issue Date, starting with "2010-02"
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- Environmental modulation of androgen levels and secondary sex characters in two populations of the peacock blenny Salaria pavoPublication . Saraiva, João L.; Gonçalves, David M.; Oliveira, Rui F.Morphology and endocrinology were studied in two populations of the peacock blenny Salaria pavo, with different regimes of sexual selection imposed by differences in nest site availability. The peacock blenny is a small, sexually dimorphic benthic fish that presents exclusive paternal care of the clutch and inhabits rocky shores of the Mediterranean and adjacent Atlantic areas. In a population from the Gulf of Trieste (Northern Adriatic sea) inhabiting rocky shores where nest sites are abundant, male-male competition for nests is low, males court females and a low frequency of alternative reproductive tactics (small, parasitic female-mimicking sneaker males that change tactic into nest holders in subsequent breeding seasons) occurs. Conversely at Ria Formosa, a coastal lagoon in Southern Portugal, where nest sites are scarce and highly aggregated, male-male competition for nests is very high, there is sex-role reversal with female courtship and a high frequency of alternative reproductive tactics is observed. Concomitantly, at Ria Formosa nest holder males are larger and present more developed secondary sex characters and higher levels of 11 KT than at the Gulf of Trieste. However, the gonads of nest holders and parasitic males were larger in the Gulf of Trieste population. Competition for nests at Ria Formosa seems to promote more developed secondary sex characters in nest site scarcity conditions, while competition for females at the Gulf of Trieste seems to be spurring sperm competition among males in populations where nest sites are more abundant. 11 KT was thus associated with the development and expression of secondary sex characters in contrasting environments. These results exemplify how the modulation of behavioral plasticity and secondary sex characters by the social environment can be mediated by androgens. (c) 2009 Elsevier Inc. All rights reserved.
- Quality of life in asthma patientsPublication . Ferreira, Lara; Brito, Ulisses; Ferreira, Pedro LopesIn this paper we present a study whose main aim is the measurement of the Health Related Quality of Life (HRQoL) of patients with asthma and the presentation of a first draft of normative values as measured by the SF-6D for asthma patients. In addition, we investigate how far non-disease-specific HRQoL measures can distinguish groups in terms of socio-demographic characteristics. The Portuguese versions of the EQ-5D, SF-6D, AQLQ(S) and ACQ were administered using personal interviews to a representative sample of the Portuguese population with asthma. Most of the individuals did not report significant problems in the dimensions used, with the exception of the physical functioning, where individuals reported moderate limitations. The mean utility value was 0.86. Male gender, young, single, individuals with high educational attainment level, employed, individuals with high income and those residing in urban areas reported higher utility levels. As expected, those who were in a severe stadium of the disease reported lower mean utility levels than those who were in a less severe stadium of the disease. Normative values for the SF-6D were computed for patients with asthma by gender, age, marital status, educational attainment level, employment status, area of residence and average monthly net income. The preference-based measures used in this study distinguish patient groups with asthma in terms of socio-demographic groups. The normative values can be used in economic evaluation and clinical studies as they incorporate patients' preferences and translate the value attributed to patients' health state.
- Omega-3 fatty acid desaturase genes isolated from Purslane (Portulaca oleracea L.): expression in different tissues and response to cold and wound stressPublication . Teixeira, Monica; Carvalho, Isabel Saraiva de; Brodelius, MariaTwo full-length cDNA clones PoleFAD7 and PoleFAD8, encoding plastidial omega-3 fatty acid desaturases were isolated from purslane (Portulaca oleracea). The encoded enzymes convert linoleic to alpha-linolenic acid (C18:3n-3). Three histidine clusters characteristic of fatty acid desaturases, a putative chloroplast transit peptide in the N-terminal, and three putative transmembrane domains were identified in the sequence. Both genes were expressed in all analyzed tissues showing different levels of expression. PoleFAD7 was up-regulated by wounding but not by low temperature. PoleFAD8 was up-regulated by cold stress but not by wounding. Total fatty acid and linolenic acid content were higher both, in wounded and intact leaves of plants exposed to low temperature.
- Vector sensor arrays in underwater acoustic applicationsPublication . Santos, P.; Felisberto, P.; Jesus, S. M.Traditionally, ocean acoustic signals have been acquired using hydrophones, which measure the pressure field and are typically omnidirectional. A vector sensor measures both the acoustic pressure and the three components of particle velocity. Assembled into an array, a vector sensor array (VSA) improves spatial filtering capabilities when compared with arrays of same length and same number of hydrophones. The objective of this work is to show the advantage of the use of vector sensors in underwater acoustic applications such as direction of arrival (DOA) estimation and geoacoustic inversion. Beyond the improvements in DOA estimation, it will be shown the advantages of using the VSA in bottom parameters estimation. Additionally, is tested the possibility of using high frequency signals (say 8-14 kHz band), acquired during the MakaiEx 2005, to allow a small aperture array, reducing the cost of actual sub-bottom profilers and providing a compact and easy-to-deploy system.
- An environmental equalizer for underwater acoustic communications Tested at Hydralab IIIPublication . Silva, A.; Zabel, F.; Mertins, C.; Ijaz, S.; Jesus, S. M.It is known that small changes in source and receiver locations can cause significant changes in underwater acoustic channel impulse responses. At HYDRALAB III an underwater acoustic experiment was conducted to show that a source depth-shift causes a frequency-shift in the channel impulse response and that such behavior can be used to implement an environmental-based equalizer for underwater communications that compensates for the performance loss due to the source depth-shift.
- Genetic structure in the Mediterranean seagrass Posidonia oceanica: disentangling past vicariance events from contemporary patterns of gene flowPublication . Serra, I. A.; Innocenti, A. M.; Di Maida, G.; Calvo, S.; Migliaccio, M.; Zambianchi, E.; Pizzigalli, C.; ARNAUD-HAOND, Sophie; Duarte, C. M.; Serrão, Ester; Procaccini, G.The Mediterranean Sea is a two-basin system, with the boundary zone restricted to the Strait of Sicily and the narrow Strait of Messina. Two main population groups are recognized in the Mediterranean endemic seagrass Posidonia oceanica, corresponding to the Western and the Eastern basins. To address the nature of the East–West cleavage in P. oceanica, the main aims of this study were: (i) to define the genetic structure within the potential contact zone (i.e. the Strait of Sicily) and clarify the extent of gene flow between the two population groups, and (ii) to investigate the role of present water circulation patterns vs. past evolutionary events on the observed genetic pattern. To achieve these goals, we utilized SSR markers and we simulated, with respect to current regime, the possible present-day dispersal pattern of Posidonia floating fruits using 28-day numerical Lagrangian trajectories. The results obtained confirm the presence of the two main population groups, without any indices of reproductive isolation, with the break zone located at the level of the Southern tip of Calabria. The populations in the Strait of Sicily showed higher affinity with Western than with Eastern populations. This pattern of genetic structure probably reflects historical avenues of recolonization from relict glacial areas and past vicariance events, but seems to persist as a result of the low connectivity among populations via marine currents, as suggested by our dispersal simulation analysis.
- Influence of temperature variations on the entropy and correlation of the Grey-Level Co-occurrence Matrix from B-Mode imagesPublication . Alvarenga, A. V.; Teixeira, C. A.; Ruano, M. Graça; Pereira, W. C. A.In this work, the feasibility of texture parameters extracted from B-Mode images were explored in quantifying medium temperature variation. The goal is to understand how parameters obtained from the gray-level content can be used to improve the actual state-of-the-art methods for non-invasive temperature estimation (NITE). B-Mode images were collected from a tissue mimic phantom heated in a water bath. The phantom is a mixture of water, glycerin, agar-agar and graphite powder. This mixture aims to have similar acoustical properties to in vivo muscle. Images from the phantom were collected using an ultrasound system that has a mechanical sector transducer working at 3.5 MHz. Three temperature curves were collected, and variations between 27 and 44 degrees C during 60 min were allowed. Two parameters (correlation and entropy) were determined from Grey-Level Co-occurrence Matrix (GLCM) extracted from image, and then assessed for non-invasive temperature estimation. Entropy values were capable of identifying variations of 2.0 degrees C. Besides, it was possible to quantify variations from normal human body temperature (37 degrees C) to critical values, as 41 degrees C. In contrast, despite correlation parameter values (obtained from GLCM) presented a correlation coefficient of 0.84 with temperature variation, the high dispersion of values limited the temperature assessment. (C) 2009 Elsevier B.V. All rights reserved.
- Parâmetros de qualidade para a aguardente de medronhoPublication . Galego, LudovinaA Aguardente de Medronho, apesar de merecer interesse por parte da Comunidade Europeia desde 1989 (Regulamento (CEE) 1576/89 do conselho de 29 de Maio de 1989, substituído pelo Regulamento (CE) Nº 110/2008 do Parlamento Europeu e do conselho de 15 de Janeiro de 2008), não teve legislação específica até o ano 2000, o que levava a que facilmente se pudessem vender diversas bebidas espirituosas com a designação de Aguardente de Medronho. A legislação só por si não impede falsificações mas limita o campo das falsificações. Também não conduz a que se produzam aguardentes de boa qualidade, até porque os limites fixados para muitos dos compostos são muito altos para produtos de qualidade. Neste campo de optimizar a qualidade dos destilados há ainda muito por fazer mas sem dúvida a actual lei foi o primeiro passo para moralizar o comércio deste destilado, há que lutar por legislação mais apertada para aguardentes de qualidade.
- Application of bismuth modified disposable screen printed carbon electrode for metal- plant thiols complexation studiesPublication . Feyssa, Belachew Tolla; Diaz-Cruz, Jose ManuelThe application of Bismuth modified cheap and disposable screen printed carbon electrode (BiSPCE) for voltammetric studies of metal–thiol rich peptides complexation was evaluated considering systems consisting of cadmium as a metal and GSH and PC2 as thiol peptides. Comparison of the performance of BiSPCE with the commonly used glassy carbon electrode (BiFE) was made. The information obtained about the complexation sequence using the former electrode was quite consistent with previous studies made on GSH and Cd systems using the conventional mercury electrodes due to the absence of signal splitting, the good sensitivity and the wider linearity range. In contrast with the conventional mercury electrodes, the anodic signals associated with bismuth electrode material were observed to be weakened and all the available signals were well resolved which shows the suitability of Bismuth based electrode for metal- thiol complexation studies. MCR-ALS could not be applied due to the continuous shift of the peak potentials, loss of linearity of the species and anomalous shape of the complex signal formed between Cd and GSH. Therefore, the complexation sequence between GSH and Cd2+ was evaluated qualitatively. However, a relatively well defined shape and intense voltammograms were observed for Cd-PC2 system and consequently, MCR-ALS was applied after correction of the continuous peak potential shift for the complex signals. The peak intensity associated with complex signal was dominated by the intense signal of the free metal reduction in acidic and fairly basic medium. However a relatively intense signal of the complexes was obtained at pH 7.5 in borate buffer solution. In addition extensive Bi complexation was observed from ESI-MS experiment which proves the suitability of ex situ mode of Bi film preparation for thiol- metal complexation studies by voltammetric titration technique.
- Optimization of an SPE clean-up approach for the analysis of sulfonamides in animal feedPublication . Kumar, Praveen Kumar; Companyó, Ramon; Cavaco, Isabel Maria Palma Antunes ,In this work, clean up strategy is optimized for an analytical method based on liquid chromatography with UV detection for determination of eight sulfonamides (sulfachloropyridazine, sulfadiazine, sulfadimidine, sulfadoxine, sulfamethoxypyridazine, sulfaquinoxaline, sulfamethoxazole and sulfadimethoxine) in pig feed. Solid Phase Extraction is used for clean up and the performance of different sorbents - C 18, Oasis HLB, Plexa and Plexa PCX is assessed by their clean up efficiency and recovery of analytes. Oasis HLB and Plexa PCX sorbents provide better clean up and recovery values than C18 and Plexa. A spiked feed of 2 mg/kg is used to assess mean recoveries and precision in terms of repeatability, r and within-lab reproducibility, R for the whole method with Oasis HLB and Plexa PCX. Recoveries using Oasis HLB ranges from 51 to 78%, with RSDr from 5 to 15% and RSDR from 5 to 18%. Recoveries using Plexa PCX ranges from 64 to 85% with RSDr from 4 to 11% and RSDR from 7 to 17%..
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