Microbial community composition and mercury cycling in sediments of tagus estuary

Tese de doutoramento, Farmácia (Toxicologia), Universidade de Lisboa, Faculdade de Farmácia, 2016

The influence of salinity and sea star wasting syndrome on sea star species composition and distribution in Nootka Sound, British Columbia

Senior thesis written for Oceanography 445

Analysis of zooplankton species composition and depth-based habitat preference in Nootka Sound, B.C., Canada

Senior thesis written for Oceanography 445

Nutritional Evaluation and Optimisation in Neonates: a randomized, double-blind controlled trial of amino acid regimen and intravenous lipid composition in preterm parenteral nutrition

Background: Parenteral nutrition is central to the care of very immature infants. Current international recommendations favor higher amino acid intakes and fish oil–containing lipid emulsions. Objective: The aim of this trial was to compare 1) the effects of high [immediate recommended daily intake (Imm-RDI)] and low [incremental introduction of amino acids (Inc-AAs)] parenteral amino acid delivery within 24 h of birth on body composition and 2) the effect of a multicomponent lipid emulsion containing 30% soybean oil, 30% medium-chain triglycerides, 25% olive oil, and 15% fish oil (SMOF) with that of soybean oil (SO)-based lipid emulsion on intrahepatocellular lipid (IHCL) content. Design: We conducted a 2-by-2 factorial, double-blind, multicenter randomized controlled trial. Results: We randomly assigned 168 infants born at ,31 wk of gestation. We evaluated outcomes at term in 133 infants. There were no significant differences between Imm-RDI and Inc-AA groups for nonadipose mass [adjusted mean difference: 1.0 g (95% CI: 2108, 111 g; P = 0.98)] or between SMOF and SO groups for IHCL [adjusted mean SMOF:SO ratio: 1.1 (95% CI: 0.8, 1.6; P = 0.58]. SMOF does not affect IHCL content. There was a significant interaction (P = 0.05) between the 2 interventions for nonadipose mass. There were no significant interactions between group differences for either primary outcome measure after adjusting for additional confounders. Imm-RDI infants were more likely than Inc-AA infants to have blood urea nitrogen concentrations .7 mmol/L or .10 mmol/L, respectively (75% compared with 49%, P , 0.01; 49% compared with 18%, P , 0.01). Head circumference at term was smaller in the Imm-RDI group [mean difference: 20.8 cm (95% CI: 21.5, 20.1 cm; P = 0.02)]. There were no significant differences in any prespecified secondary outcomes, including adiposity, liver function tests, incidence of conjugated hyperbilirubinemia, weight, length, mortality, and brain volumes. Conclusion: Imm-RDI of parenteral amino acids does not benefit body composition or growth to term and may be harmful. This trial was registered at www.isrctn.com as ISRCTN29665319 and at eudract.ema.europa.eu as EudraCT 2009-016731-34.

Higher-order moments in the theory of diversifying and portfolio composition

This paper examines the role of higher-order moments in portfolio choice within an expected-utility framework. We consider two-, three-, four- and five-parameter density functions for portfolio returns and derive exact conditions under which investors would all be optimally plungers rather than diversifiers. Through comparative statics we show the importance of higher-order risk preference properties, such as riskiness, prudence and temperance, in determining plunging behaviour. Empirical estimates for the S&P500 provide evidence for the optimality of diversification.

Composition and antioxidant activity of thymus vulgaris volatiles: comparison between supercritical fluid extraction and hydrodistillation

Supercritical fluid extraction (SEE) of the volatile oil from Thymus vulgaris L. aerial flowering parts was performed under different conditions of pressure, temperature, mean particle size and CO2 flow rate and the correspondent yield and composition were compared with those of the essential oil isolated by hydrodistillation (HD). Both the oils were analyzed by GC and GC-MS and 52 components were identified. The main volatile components obtained were p-cymene (10.0-42.6% for SFE and 28.9-34.8% for HD), gamma-terpinene (0.8-6.9% for SFE and 5.1-7.0% for HD), linalool (2.3-5.3% for SFE and 2.8-3.1% for HD), thymol (19.5-40.8% for SFE and 35.4-41.6% for HD), and carvacrol (1.4-3.1% for SFE and 2.6-3.1% for HD). The main difference was found to be the relative percentage of thymoquinone (not found in the essential oil) and carvacryl methyl ether (1.0-1.2% for HD versus t-0.4 for SFE) which can explain the higher antioxidant activity, assessed by Rancimat test, of the SFE volatiles when compared with HD. Thymoquinone is considered a strong antioxidant compound.

Angolan cymbopogon citratus used for therapeutic benefits: nutritional composition and influence of solvents in phytochemicals content and antioxidant activity of leaf extracts

Folk medicine is a relevant and effective part of indigenous healthcare systems which are, in practice, totally dependent on traditional healers. An outstanding coincidence between indigenous medicinal plant uses and scientifically proved pharmacological properties of several phytochemicals has been observed along the years. This work focused on the leaves of a medicinal plant traditionally used for therapeutic benefits (Angolan Cymbopogon citratus), in order to evaluate their nutritional value. The bioactive phytochemical composition and antioxidant activity of leaf extracts prepared with different solvents (water, methanol and ethanol) were also evaluated. The plant leaves contained ~60% of carbohydrates, protein (~20%), fat (~5%), ash (~4%) and moisture (~9%). The phytochemicals screening revealed the presence of tannins, flavonoids, and terpenoids in all extracts. Methanolic extracts also contained alkaloids and steroids. Several methods were used to evaluate total antioxidant capacity of the different extracts (DPPH; NO; and H2O2 scavenging assays, reducing power, and FRAP). Ethanolic extracts presented a significantly higher antioxidant activity (p < 0.05) except for FRAP, in which the best results were achieved by the aqueous extracts. Methanolic extracts showed the lowest radical scavenging activities for both DPPH; and NO; radicals.

The effect of metal transfer modes and shielding gas composition on the emission of ultraafine particles in MAG steel welding

The present study aims to characterize ultrafine particles emitted during gas metal arc welding of mild steel and stainless steel, using different shielding gas mixtures, and to evaluate the effect of metal transfer modes, controlled by both processing parameters and shielding gas composition, on the quantity and morphology of the ultrafine particles. It was found that the amount of emitted ultrafine particles (measured by particle number and alveolar deposited surface area) are clearly dependent from the main welding parameters, namely the current intensity and the heat input of the Welding process. The emission of airborne ultrafine particles increases with the current intensity as fume formation rate does. When comparing the shielding gas mixtures, higher emissions were observed for more oxidizing mixtures, that is, with higher CO2 content, which means that these mixtures originate higher concentrations of ultrafine particles (as measured by number of particles. by cubic centimeter of air) and higher values of alveolar deposited surface area of particles, thus resulting in a more hazardous condition regarding welders exposure.

Molecular mobility, composition and structure analysis in glycerol plasticised chitosan films

This study was developed with the purpose to investigate the effect of polysaccharide/plasticiser concentration on the microstructure and molecular dynamics of polymeric film systems, using transmission electron microscope imaging (TEM) and nuclear magnetic resonance (NMR) techniques. Experiments were carried out in chitosan/glycerol films prepared with solutions of different composition. The films obtained after drying and equilibration were characterised in terms of composition, thickness and water activity. Results show that glycerol quantities used in film forming solutions were responsible for films composition; while polymer/total plasticiser ratio in the solution determined the thickness (and thus structure) of the films. These results were confirmed by TEM. NMR allowed understanding the films molecular rearrangement. Two different behaviours for the two components analysed, water and glycerol were observed: the first is predominantly moving free in the matrix, while glycerol is mainly bounded to the chitosan chain. (C) 2013 Elsevier Ltd. All rights reserved.

How to Measure the Deterrence Effects of Merger Policy: Frequency or Composition?

We show that the number of merger proposals (frequency-based deterrence) is a more appropriate indicator of underlying changes in merger policy than the relative anti-competitiveness of merger proposals (composition-based deterrence). This has strong implications for the empirical analysis of the deterrence effects of merger policy enforcement, and potential implications regarding how to reduce anti-competitive merger proposals.

Pozzolanic components in lime mortars: correlating behaviour, composition and microstructure.

Int. J. for Restoration of Buildings and Monuments, vol.11, nº 2 (2005), p.111-118

Determination of microalgae cellular composition after phycoremediation of swine wastewaters.

Phycoremediation of swine wastewaters has been widely reported as an attractive tertiary treatment system, that effectively removes the excessive nutrient loadswhilst offering a valuable source of feedstock biomass. Digestate from an upflow anaerobic sludge blanket (UASB, 6%v/v) and a nitrification reactor (NR; 50% v/v) were used as culturing media to microalgae. Experiments were carried out in lab scale photobioreactors (PBRs) using a consortia of Chlorella and Scenedesmus. Ammonia (44 to 90%) and phosphorus (77%) were efficiently removed from both effluents tested after 4 days. Microalgae biomass harvested from the UASB effluent showed 57, 34 and 1% of proteins, carbohydrates and lipids, respectively. Comparatively, the cellular composition of microalgae grown on NR effluent had lower protein (43%) but higher carbohydrate (42%) contents. Negligible difference in lipid fraction was observed independently of the effluents tested. The results suggest that the biomass harvested from phycoremediation of swine wastewaters can offer a valuable protein and carbohydrate feedstock for nutritional and biotechnological applications.

Valorisation of vegetable oil deodorizer distillate by enzymatic reaction and membrane processing

Dissertação para obtenção do Grau de Doutora em Engenharia Química e Bioquímica

Trading the changes of stock market index composition: Evidence from European markets

This paper studies the changes in European stock market indexes composition from 1995 to 2015. It was found that there are mixed price effects producing abnormal returns around the effective replacement of added and deleted stocks. The price pressure hypothesis seems to hold for added stocks in some indexes but not for deleted stocks as there is not a clear inversion of behaviour after the replacement. Finally, the building and back testing of a trading strategy aiming to capture some of those abnormal returns shows it yields a Sharpe Ratio of 1.4 and generates an annualised alpha of 11%.

The impact of the Board of Director's composition on companies performance

The impact of the Board of Directors’ composition on companies’ performance This paper studies the impact that the board of directors’ composition has on companies’ performance in the Italian market. The research has been carried out by using a sample of 10 Italian companies, across different market sectors, over a period of 10 years (2005-2014). The characteristics of the BoD taken into consideration are the following: board size, board diversity (% of female directors), board independence and CEO duality. Results from the sample data collected concluded that these factors have a statistically significant impact on the performance of the companies that have been analysed.