Evolution of ethyl carbamate during Madeira wine ageing by GC-MS: a new methodology

Recently, ethyl carbamate (EC) was reclassified by the International Agency for Research on Cancer (IARC) as "probably carcinogenic to humans" and occurs mainly in fermented beverages. Nowadays many countries have set limit values for EC in alcoholic beverages. In this sense and taking into account the low concentrations found in alcoholic beverages, the scientific community has shown interest for the development of new analytical methods, whereby its simplification plays an important role in the EC control and prevention. Firstly, a simple, rapid and sensitive methodology was developed for the EC quantification in fortified wines by microextraction by packed sorbent (MEPS) with gas chromatography coupled with a mass spectrometer detector (GC-MS). This method showed good linearity (R2 = 0.999) and sensitivity (LOD = 1.5 μg/L). The accuracy of the method was assessed by means of repeatability and reproducibility (RSD < 7%). Moreover, a good recovery has been demonstrated (97 – 106%) as well as its applicability (16 fortified wines). Thus, the developed methodology has proven to be an excellent approach for routine quantification of EC in fortified wines. The EC evolution was also evaluated during a year and half of Madeira wine ageing submitted to two traditional ageing methods, estufagem and canteiro, in order to evaluate the formation kinetic. The results revealed that estufagem process increased the formation kinetic and promoted a linear increase of the EC concentration (R2 ≥ 0.977), proportionally to the ageing time (4 months). However, when the wines are firstly submitted to estufagem and then undergo canteiro ageing, the EC values remain almost constant during the following 14 months. The results suggest that estufagem does not seem to be the critical factor in the EC formation, but instead the amount of precursors in the medium.

Evolution of the landscape of Madeira Island: long-term vegetation dynamics

The aim of this thesis was to evaluate historical change of the landscape of Madeira Island and to assess spatial and temporal vegetation dynamics. In current research diverse “retrospective techniques”, such as landscape repeat photography, dendrochronology, and research of historical records were used. These, combined with vegetation relevés, aimed to gather information about landscape change, disturbance history, and vegetation successional patterns. It was found that landscape change, throughout 125 years, was higher in the last five decades manly driven by farming abandonment, building growth and exotic vegetation coverage increase. Pristine vegetation was greatly destroyed since early settlement and by the end of the nineteenth century native vegetation was highly devastated due to recurrent antropogenic disturbances. These actions also helped to block plant succession and to modify floristical assemblages, affecting as well as species richness. In places with less hemeroby, although significant growth of vegetation of lower seral stages was detected, the vegetation of most mature stages headed towards unbalance between recovery and loss, being also very vulnerable to exotic species encroachment. Recovery by native vegetation also occurred in areas formerly occupied by exotic plants and agriculture but it was almost negligible. Vegetation recovery followed the successional model currently proposed, attesting the model itself. Yet, succession was slower than espected, due to lack of favourable conditions and to recurrent disturbances. Probable tempus of each seral stage was obtained by growth rates of woody taxa estimated through dendrochronology. The exotic trees which were the dominant trees in the past (Castanea sativa and Pinus pinaster) almost vanished. Eucalyptus globulus, the current main tree of the exotic forest is being replaced by other cover types as Acacia mearnsii. The latter, along with Arundo donax, Cytisus scoparius and Pittosporum undulatum are currently the exotic species with higher invasive behaviour. However, many other exotic species have also proved to be highly pervasive and came together with the ones referred above to prevent native vegetation regeneration, to diminish biological diversity, and to block early successional phases delaying native forest recovery.

ESR dating of pleistocene mammal teeth and its implications for the biostratigraphy and geological evolution of the coastal plain, Rio Grande do Sul, southern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Annual evolution of global, direct and diffuse radiation and fractions in tilted surfaces

Avaliou-se a evolução anual das componentes global, direta e difusa da radiação solar incidente em superfícies inclinadas a 12,85; 22,85 e 32,85º, com face voltada ao Norte, em Botucatu-SP. Foram obtidas frações radiométricas para cada componente da radiação nas superfícies supracitadas, através de razões com a radiação global e a do topo da atmosfera. A sazonalidade foi avaliada através das médias mensais dos valores diários. As medidas ocorreram entre 04/1998 e 07/2001, em 22,85º; 08/2001 e 02/2003, em 12,85º; e de 03/2003 a 12/2007, em 32,85º, com medidas concomitantes no plano horizontal (referência). Os níveis das radiações global e direta nos planos inclinados foram inferiores no período de verão e superiores entre os equinócios, quando comparadas ao plano horizontal. A radiação difusa nas superfícies inclinadas foi inferior na maioria dos meses, com perdas de até 65%. Ocorreu uma tendência de aumento das diferenças entre as superfícies horizontal e inclinada com o incremento do ângulo em todas as componentes e frações da radiação incidente. A evolução anual das precipitações pluviométricas e da razão de nebulosidade afetou diretamente a transmissividade atmosférica das componentes direta e difusa na região.

Growth evolution of ZnO thin films deposited by RF magnetron sputtering

We study the surface morphology evolution of ZnO thin films grown on glass substrates as a function of thickness by RF magnetron sputtering technique. The surface topography of the samples is measured by atomic force microscopy (AFM). All AFM images of the films are analyzed using scaling concepts. The results show that the surface morphology is initially formed by a small grains structure. The grains increase in size and height with growth time resulting in the formation of a mounds-like structure. The growth exponent, beta, and the exponent defining the evolution of the characteristic wavelength of the surface, p, amounted to beta = 0.76 +/- 0.08 and p = 0.3 +/- 0.05. From these exponents, the surface morphology is determined by the nonlocal shadowing effects, that is the dominant mechanism, due to the incident deposition particles during film growth.

Fluctuating solutions for the evolution of domain walls

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Dynamical evolution of Saturn's F ring dust particles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Orbital evolution of the mu and nu dust ring particles of Uranus

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Microstructural Evolution of Ti-6Al-7Nb Alloy During High Pressure Torsion

Ti-6Al-7Nb alloys are being evaluated for biomedical applications, in substitution of the more conventional Ti-6Al-7V. Both types of alloys present a microstructure containing the alpha and the beta phases, which result in good compromise for mechanical applications. In the present work Ti-6Al-7Nb alloys were processed by High Pressure Torsion (HPT), varying the number of revolutions and thus the total imposed strain. X-Ray Diffraction (XRD) results revealed the formation of different crystallographic textures in samples subjected to HPT. Microhardness distribution, across the diameters of the disks, is rather homogeneous for all samples, with higher values for those subjected to 03 and 05 turns. Transmission electron microscopy (TEM) micrographs have showed that an ultra-fine grained microstructure was obtained in all the samples.

Morphological evolution of tin oxide nanobelts after phase transition

This article reports a study of the thermal stability and morphological changes in tin oxide nanobelts grown in the orthorhombic SnO phase. The nanobelts were heat-treated in a differential scanning calorimetry (DSC) furnace at 800 degrees C for I It in argon, oxygen, or synthetic air atmospheres. The samples were then characterized by DSC, X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and high resolution field emission scanning electron microscopy (FE-SEM). The results confirmed that the orthorhombic SnO phase is thermodynamically unstable, causing the belts to transform into the SnO2 phase when heat-treated. During the phase transition, if oxygen is available in the furnace atmosphere, nanofibers grow at the edge of nanobelts at about 50 degrees of the belts' growth direction, while particles grow on the belt surface in the absence of oxygen. Although the decomposition process reduces the nanobelt cell volume by 22%, most belts remain monocrystalline after the heat treatment. The results confirm that phase transition is a decomposition process, which explains the morphological changes in the belts based on metallic tin generated in the process.

Evolution of representation of the hands in plastic arts

A interação entre arte e ciência foi intensa durante o Renascimento, sofrendo declínio nos anos posteriores com retomada significativa no século XX, principalmente com o uso de técnicas de identificação, datação de obras de arte e o desenvolvimento de novos materiais. O relacionamento entre artes plásticas e Cirurgia da Mão mantêm-se intenso , sendo freqüente o uso de reproduções artísticas da mão nas ilustrações de textos científicos. Objetivando compreender o papel da mão nas artes plásticas, reproduções de obras de artes (esculturas e pinturas) representativas de vários estilos ou períodos da história da arte foram analisadas com enfoque no estudo das mãos. Detalhes anatômicos, relacionamento com outras estruturas do corpo humano, papel na composição e aspectos simbólicos das mãos foram estudados no contexto histórico e artístico de obras de arte do período paleolítico (pré-história) até o século XX. A representação da mão nas artes plásticas está diretamente relacionada ao estilo ou período da obra e à capacidade individual de interpretação e execução do artista.