Contributo para o estudo das plantas vasculares endémicas da Ilha das Flores (Açores).

IV Expedição Científica do Departamento de Biologia – Flores 1989.Conforme mostra MALATO-BELIZ (1988), o número de taxa vasculares endémicos nas ilhas dos Açores varia entre um máximo de 62 taxa (ilha de S. Miguel) e um mínimo de 11 taxa endémicos na ilha Graciosa. A pequena ilha das Flores com 51 taxa endémicos ultrapassa claramente neste particular as ilhas Graciosa (11), S. Maria (35) e Corvo (37) e quase iguala em número de espécies endémicas ilhas bastante maiores como a Terceira (55) e o Faial (55). Não admira pois que em termos da relação "nº taxa endémicos/unidade de superfície (Km2)" a ilha das Flores com 0,357 end./Km2, apenas seja ultrapassada por S. Maria (0,360 end./ Km2) e pelo Corvo (2,126 end./Km2), 0 valor médio para o arquipélago situa-se apenas nos 0,184 end./Km2. A explicação para esta relativa riqueza em espécies endémicas da ilha das Flores fica sem dúvida a dever-se à grande diversidade de biótopos que ela possui e à existência de algumas manchas vegetais menos alteradas pelo homem

Pathway Weathering in Granitoid Rocks from Central Region of Angola: Geochemical and Mineralogical Data

The Central Region of Angola is characterized by the abundance of granitoid rocks, whose weathering “in situ” originated the so-called residual soils. The textural, geochemical and mineralogical properties of these soils depend not only on the chemical composition of parent rock, but mainly on the local climatic and geomorphological characteristics. In the study area, sampling sites were selected, which extend from the region of Kwanza- Norte (Kassenda, Dondo) through Kwanza-Sul (Cangulo, Quibala and Waco Kungo) until the plateau of Huambo, where samples of fresh rock, weathered rock and its residual soil were collected along each weathering profile. Chemical analytical data were determined using X-ray fluorescence (XRF) analysis of the major and minor elements, whereas mineralogical data were determined using X-ray diffraction (XRD), on the samples of rock and on the respective residual soil. The results obtained and their comparative analysis between the sampling sites, as well as along each weathering profile is presented. This paper allows contributing to the knowledge of the geochemical weathering in tropical areas, as is the case of Angola

Caracterização mineralógica e geotécnica dos solos para a construção em terra crua no sudoeste de Angola

RESUMO A construção feita em terra crua é um património cultural em Angola amplamente utilizado por famílias de baixa renda. No sudoeste de Angola existem inúmeras habitações de terra crua construídas com métodos e técnicas ancestrais que respeitam o meio ambiente. Entre as técnicas de construção em terra, destacam-se: o adobe, o pau-a-pique e mais recentemente em BTC (Bloco de Terra Comprimida). A sustentabilidade deste tipo de construção é um dos fatores que impulsionou o seu recente desenvolvimento em todo o mundo. É caracterizada por baixo consumo de energia e baixas emissões de carbono porque está associada a níveis de poluição perto de zero, por possuir níveis benéficos de humidade interna em termos de saúde humana, bom isolamento térmico e baixos custos económicos. Este trabalho faz parte de um projeto que visa melhorar e otimizar essas soluções construtivas, respondendo às demandas atuais de sustentabilidade social, económica e ambiental. Neste trabalho foram caracterizadas as propriedades mineralógicas de oito amostras de solos utilizados na construção em terra crua na região do sudoeste de Angola (província da Huíla), mediante a aplicação da técnica de análise mineralógica por Difração de raios-X (DRX) e as características geotécnicas (dimensões das partículas do solo, consistência, expansibilidade, densidade, compactação). Além disso, para avaliar a durabilidade dos adobes foram realizados os testes Geelong. Os resultados obtidos põem em evidência que as propriedades mineralógicas controlam as propriedades geotécnicas dos solos e o comportamento dos mesmos quando utilizados na construção em terra. ABSTRACT The construction made off raw earth is a cultural heritage in Angola widely used by low income households. In Southwest of Angola there are numerous dwellings of raw earth built with methods and ancestral techniques that respect the environment. Among the construction techniques in earth, stand out: the adobe, wattle-and-daub and more recently on CEB (Compressed Earth Block). The sustainability of this type of construction is one of the factors that has driven its recent development around the world. It is characterized by low energy consumption and low carbon emissions because it is associated with levels of pollution near zero, it provides beneficial indoor humidity levels in terms of human health, good thermal insulation and low economic costs. This work is part of a project, which aims to improve and optimize these constructive solutions, responding to the current demands of social, economic and environmental sustainability. In this work the mineralogical and mechanical properties of the soils used in the construction on raw earth in this region were characterized, in order to identify its potentialities and limitations as geomaterial in this type of eco-construction. In this work, the mineralogical properties of eight soil samples used in the construction in the ground in the southwestern region of Angola (Huíla province) were characterized by the application of mineralogical analysis by X-ray diffraction technique and the geotechnical characteristics (particle size, consistency, expansibility, density, Proctor compaction). In addition, the Geelong tests were performed to prove the durability of the adobes. The results show that the mineralogical properties control the geotechnical properties of the soils and their behavior for the construction on raw earth

A construção sustentável na perspetiva dos geomateriais utilizados na Província da Huíla, Angola

A construção sustentável centra-se na busca da necessidade de maior eficiência energética, menor preço e maior durabilidade, com o objetivo de obter uma edificação que não agrida o meio ambiente, mas também com melhor conforto térmico, com reduzida necessidade de consumo de energia e com melhoria da qualidade de vida dos seus moradores. Na província da Huíla, Angola, existem inúmeras habitações de terra crua que constituem uma verdadeira herança cultural e que têm sido construídas com base em métodos e técnicas ancestrais que respeitam o ambiente. Os materiais utilizados e as características construtivas diferem, sobretudo, em função do rendimento das próprias famílias e dos materiais disponíveis, sendo o adobe, o método construtivo em terra que assume uma maior presença nesta região, não obstante a existência de edificações de pau-a-pique e, mais recentemente, em blocos de terra comprimida. O principal objetivo deste estudo é avaliar e relacionar a composição mineralógica e textural dos solos com as respetivas características físicas e mecânicas, de forma a identificar as suas potencialidades e limitações como material de construção em terra crua nesta região. Para o efeito, foram colhidas 8 amostras de solos e adobes fabricados nos respetivos locais, de modo a realizarem-se ensaios específicos cujos resultados possibilitaram a identificação e caracterização destes geomateriais. Neste trabalho, realizaram-se os ensaios in-situ e laboratoriais para determinar as propriedades mineralógicas (DRX), as físicas (granulometria, consistência, expansibilidade, densidade), as mecânicas, os ensaios Geelong e o ensaio de avaliação do ciclo húmido/seco, de acordo com as normas Neozelandesas, NZS 4298 (1998) e 4297 (1998). Esta investigação contribui para a caracterização dos geomateriais utilizados na construção em terra crua nesta região de Angola, contribuindo assim, para o desenvolvimento de soluções construtivas sustentáveis e com características melhoradas, de conforto, segurança e de durabilidade

Influencia de la anisotropic en la durabilidad de las dolomías Cretácicas de la Comunidad de Madrid frente a la cristalización de sales

The behaviour of dolostone exposed to the effects of salt crystallization processes was studied on materials from Redueña and Torrelaguna in the province of Madrid, Spain. Much of the region's architectural and monumental heritage was built with the materials from these two sites. Stone specimens were selected for testing on the basis of ultrasonic wave propagation velocity (Vp) measurements taken in around one hundred cubic samples of each variety. The anisotropy indices were calculated and the samples were clustered on the basis of the results. Two representative samples of each class were taken and characterized for their petrographic and petrophysical properties before and after exposure to salt crystallization cycles. Ageing was evaluated in terms of weight loss and the visual deterioration observed. The pattern of decay found varied substantially in the two materials: the Redueña material exhibited more intense deterioration, with scaling and spalling, while the Torrelaguna dolostone tended to generate fragmentation and rounding at corners and edges.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEComunidad de MadridMinisterio de EducaciónUnión Europeapu

Soil mineralogical composition effects on the durability of adobe blocks from the Huambo region, Angola

After many years of war, great efforts have been made for the socio-economic development of Angola, particularly in the construction industry. Among the construction techniques, adobe is one of the most used in the province of Huambo, especially by low-income families, which constitute the majority. This technique was established as an intangible heritage in the culture of that population. Huambo province is located in the central region of Angola (Central Plateau). Adobe blocks are building elements with potential degradation by the action of water. Due to the subtropical climate, hot and humid, and geomorphology of the province, located at about 1000–2000 m of altitude and with an extensive river system, these buildings can be vulnerable and may present premature degradation, exacerbated by the lack of knowledge concerning the properties of the geomaterials used and techniques/solutions that allow their stabilization and conservation. This paper aims to present the main results of the study to investigate the influence on adobe performance in regard to the mineralogy and geochemistry of soils used in the production of adobes used in the construction of dwellings. The knowledge gained with this research can support the development of solutions for the common anomalies and problems in this construction, as well as to improve the strength and durability of the adobe units. For this purpose, soil samples were collected and mineralogical, geochemical, and physical tests were performed. Durability and erodibility tests were also performed on selected adobes, following the Geelong method. The results obtained with this research may contribute to the development of the knowledge concerning this sustainable building solution, which has a strong presence in the province of Huambo and neighbouring regions.FCT - UID/GEO/04035/201

Charged quark stars in metric f(R)f(R) gravity

We provide the modified TOV equations for the hydrostatic equilibrium of charged compact stars within the metric $f(R)$ gravitational background. We adopt the MIT bag model EoS for the dense matter and assume a charge distribution where the electric charge density $\rho_{\rm ch}$ is proportional to the standard energy density $\rho$. Using the Starobinsky model, we explore the role of the $\alpha R^2$ term, where $\alpha$ is a free constant and $R$ the Ricci scalar, on the global properties of charged stars such as radius, mass and total charge. We present the dependence of the structure of the star for several values of $\alpha$ and for different values of the constant parameter $\beta\equiv \rho_{\rm ch}/\rho$. Remarkably, we find that the radius decreases with respect to its GR value for low central densities, while the opposite occurs in the high-central-density region. The mass measured at the surface always decreases and the maximum-total charge undergoes a substantial increase as the parameter $\alpha$ increases. We also illustrate the variations of the asymptotic mass as a consequence of the electric charge and the extra quadratic term.Comment: 11 pages, 7 figures. To appear in JCA

Alteração de Rochas Granitóides em Angola.

A Região Central de Angola caracteriza-se pela abundância de rochas granitóides, cuja alteração “in-situ” originou os denominados solos residuais. As propriedades texturais, geoquímicas e mineralógicas destes solos dependem não só da composição química da rocha mãe, mas principalmente das características geomorfológicas e climatéricas locais. Na região em estudo, seleccionaram-se locais de amostragem, que se estendem desde a província do Kwanza-Norte (Kassenda, no Alto Dondo), passando pela província do Kwanza-Sul (Cangulo, Quibala e Waco Kungo), até ao Planalto do Huambo, onde se colheram amostras de rocha sã, rocha alterada e respectivo solo residual, ao longo de cada perfil de alteração. Realizaram-se análises de caracterização geoquímica por Fluorescência de Raios-X dos elementos maiores e menores, e de caracterização mineralógica por Difracção de Raios–X, tanto nas amostras de rocha sã, como no respectivo solo residual. Apresentam-se os resultados obtidos e a sua análise comparativa entre os diferentes locais de amostragem, assim como ao longo de cada perfil de alteração. Os resultados obtidos permitem contribuir para o conhecimento dos fenómenos de alteração geoquímica em zonas tropicais, como é o caso de Angola

Effects of grass silage and soybean meal supplementation on milk production and milk fatty acid profiles of grazing dairy cows

Copyright © American Dairy Science Association, 2008.The effects of supplementation with grass silage and replacement of some corn in the concentrate with soybean meal (SBM) on milk production, and milk fatty acid (FA) profiles were evaluated in a replicated 4 × 4 Latin square study using 16 dairy cows grazing pasture composed of ryegrass, Kentucky bluegrass, and white clover. Each experimental period lasted for 3 wk. The 4 dietary treatments were PC, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn-based concentrate mixture (96% corn; C); PCSB, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn- and SBM-based concentrate mixture (78% corn and 18% SBM; CSB); SC, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of C concentrate; and SCSB, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of CSB concentrate. The concentrate mixtures were offered twice each day in the milking parlor and were consumed completely. Grass silage supplementation reduced dietary crude protein and concentration of total sugars, and dietary SBM inclusion increased dietary crude protein concentration and decreased dietary starch concentration. Milk yield and energy-corrected milk were increased by SBM supplementation of cows with access to grass silage. Milk protein concentration was lower in cows offered grass silage, regardless of whether SBM was fed. Dietary SBM inclusion tended to increase milk fat concentration. Plasma urea N was reduced by silage feeding and increased by SBM supplementation. Supplementation with grass silage overnight could represent a useful strategy for periods of lower pasture availability. Dietary inclusion of SBM in solely grazing cows had no effects on milk production and composition, exacerbated the inefficient capture of dietary N, and increased diet cost. Grass silage supplementation affected milk FA profiles, increasing both the FA derived from de novo synthesis and those derived from rumen microbial biomass, and decreasing the sum of C18 FA (mostly derived from diet or from mobilization of adipose tissue reserves). Milk fat concentrations of conjugated linoleic acid cis-9, trans-11, vaccenic acid (18:1 trans-11), and linolenic acid (18:3n-3) were unaffected by grass silage supplementation, suggesting that partial replacement of pasture by unwilted grass silage does not compromise the dietary quality of milk fat for humans