Linking plant composition and arthropod abundance to establish little bustard breeding requirements in pastureland dominated landscapes

Most research on steppe bird habitat selection has been focused on the effects of management regimes or vegetation structure. However, much less is known on how plant composition is related with steppe bird occurrence. We investigated microhabitat of little bustard territorial males and females during the nesting and chick-rearing season in areas with dominance of pastureland focusing on plant composition. We searched for relationships between preferred vegetation and arthropod abundance in order to identify the contribution of different vegetation typologies in providing essential trophic resources for the species. Surveys of little bustards were made using car and foot transects. Plant composition was obtained within a 50 × 50 cm square at four sampling replicates and arthropod availability was sampled using a sweep net. Statistical procedures were conducted in three steps: (1) analysis of variance was used to identify at univariate level the plant composition and arthropod variables that were significantly related with both male and female occurrence sites; (2) principal components analysis was performed using the variables with significant results at univariate level; (3) model averaging on generalized linear and mixed models was applied to evaluate the selection probability of each principal component. The species occurs in sites with high floristic richness and high abundance of Fabaceae species, although plant composition differs from male to female sites. These variables were found to be crucial to provide higher abundances of arthropods, notably of Acrididea, Formicidae and some groups of Coleoptera which are decisive for the selection of displaying or female breeding sites

The importance of grazing regime in the provision of breeding habitat for grassland birds: The case of the endangered little bustard (Tetrax tetrax)

In Mediterranean dry grasslands, grazing by domestic animals is an important agricultural activity on dry grasslands. Several bird species occur in these grazed habitats and are now experiencing a near continuous decline. We investigated the impact of livestock grazing on the threatened little bustard (Tetrax tetrax L.). The study was conducted at the NATURA 2000 Site/Important Bird Area of Cabrela, Portugal. Our main goals were to investigate responses of little bustard territorial males and breeding females to different livestock management practices, namely pasture types, stocking rates and sward structure. Bird distribution was surveyed using car and foot surveys. Data on grazing was supplied by land managers every 10 days from February to June through field interviews. Generalised additive models and model averaging were used to compute predictive models. Results indicate that higher probabilities of occurrence were found in long-term pastures and under light-moderate grazing conditions (stocking rates around 0.4 LU/ha). Conversely, lower probabilities of occurrence were found in ungrazed or heavy grazed fields. Males occurred mostly in large fields, but this variable seemed to be less important for females. On the other hand, green plant cover and the vegetation height were good predictors for the occurrence of females but not for males. Females used mostly pastures with vegetation height around 20–25 cm. Our results suggest that grazing management plans that aim to conserve little bustard populations should consider (1) the maintenance of the larger long-term pastures and (2) the use of light-moderate stocking rates (0.2–0.6 LU/ha)

Guarda Nacional Republicana e Autoridade Tributária e Aduaneira: Colaboração e cooperação na Região Autónoma da Madeira

O presente estudo pretende dar a conhecer a forma como a Guarda Nacional Republicana e a Autoridade Tributária e Aduaneira se relacionam no cumprimento de uma das suas missões: o combate à fraude e evasão fiscais na Região Autónoma da Madeira. Esta investigação tem como objetivo geral compreender como é que o Comando Territorial da Madeira e a Autoridade Tributária e Aduaneira cooperam e colaboram entre si. Assim, para aprofundar esta investigação, formulou-se a seguinte questão de partida: “Quais os mecanismos de colaboração e de cooperação existentes entre a GNR e a Autoridade Tributária e Aduaneira na Região Autónoma da Madeira?”. Deste modo, para complementar e responder melhor a esta questão, surgiram questões derivadas, que, por sua vez, deram origem a hipóteses através de um método hipotético-dedutivo. Consequentemente erigiu-se um enquadramento normativo que permite dar suporte à recolha de dados, e um trabalho de campo que proporcionou conhecimentos oriundos dos responsáveis institucionais. Por fim, estas duas partes em harmonia permitiram a verificação das hipóteses. Na articulação da parte teórica e da parte prática realizada, conclui-se que o Comando Territorial da Madeira colabora e coopera com a Autoridade Tributária e Aduaneira na realização de operações conjuntas no âmbito operacional e na partilha constante de informações e que a Autoridade Tributária e Aduaneira, representada na Região Autónoma da Madeira pela Alfândega do Funchal, atua em operações conjuntas com esta Unidade no combate às infrações aduaneiras. Por fim, o Comando Territorial da Madeira tem procurado realizar operações conjuntas no âmbito fiscal não sendo, no entanto, acompanhada neste objetivo pela Direção Regional dos Assuntos Fiscais.The present study intends to show how Guarda Nacional Republicana and the Tax Authority and Customs relate in the fight against fraud and tax evasions in the Autonomous Region of Madeira. This research aims to understand how the Territorial Command of Madeira and the Tax Authority and Customs cooperate and collaborate among themselves. Thus, to better exploit the research, we formulated the following central question: "What are the existing collaboration and cooperation mechanisms between the GNR and the Tax Authority and Customs of the Autonomous Region of Madeira?". In order to complement and respond to this question, derived questions emerged, which in turn, originated hypothesis, supported by the hypothetical-deductive method. The methodology used for the elaboration of the work was divided into two parts: the theoretical part that allowed us to start the collection of data, and the practical, part the fieldwork, that provided us information on the part of institutional leaders. Finally, these two parts together allowed us to verify the hypothesis. At the articulation of the theoretical part and the practical part, it could be concluded that the Territorial Command of Madeira exercises collaboration and cooperation with the Tax Authority and Customs in joint operations in an operational framework and in constant sharing of information. It could also be concluded that the Tax Authority and Customs is represented in the Autonomous Region of Madeira by Funchal's Customhouse, acts in joint operations with the Territorial Command of Madeira in the customs field. The Territorial Command of Madeira has been looking to undertake joint operations in the tax field, however, the Regional Directorate of Tax Affairs hasn't been putting up an effort for that to happen

High performance data processing

Dissertação de mestrado em Informatics EngeneeringÀ medida que as aplicações atingem uma maior quantidade de utilizadores, precisam de processar uma crescente quantidade de pedidos. Para além disso, precisam de muitas vezes satisfazer pedidos de utilizadores de diferentes partes do globo, onde as latências de rede têm um impacto significativo no desempenho em instalações monolíticas. Portanto, distribuição é uma solução muito procurada para melhorar a performance das camadas aplicacional e de dados. Contudo, distribuir dados não é uma tarefa simples se pretendemos assegurar uma forte consistência. Isto leva a que muitos sistemas de base de dados dependam de protocolos de sincronização pesados, como two-phase commit, consenso distribuído, bloqueamento distribuído, entre outros, enquanto que outros sistemas dependem em consistência fraca, não viável para alguns casos de uso. Esta tese apresenta o design, implementação e avaliação de duas soluções que têm como objetivo reduzir o impacto de assegurar garantias de forte consistência em sistemas de base de dados, especialmente aqueles distribuídos pelo globo. A primeira é o Primary Semi-Primary, uma arquitetura de base de dados distribuída com total replicação que permite que as réplicas evoluam independentemente, para evitar que os clientes precisem de esperar que escritas precedentes que não geram conflitos sejam propagadas. Apesar das réplicas poderem processar tanto leituras como escritas, melhorando a escalabilidade, o sistema continua a oferecer garantias de consistência forte, através do envio da certificação de transações para um nó central. O seu design é independente de modelos de dados, mas a sua implementação pode tirar partido do controlo de concorrência nativo oferecido por algumas base de dados, como é mostrado na implementação usando PostgreSQL e o seu Snapshot Isolation. Os resultados apresentam várias vantagens tanto em ambientes locais como globais. A segunda solução são os Multi-Record Values, uma técnica que particiona dinâmicamente valores numéricos em múltiplos registros, permitindo que escritas concorrentes possam executar com uma baixa probabilidade de colisão, reduzindo a taxa de abortos e/ou contenção na adquirição de locks. Garantias de limites inferiores, exigido por objetos como saldos bancários ou inventários, são assegurados por esta estratégia, ao contrário de muitas outras alternativas. O seu design é também indiferente do modelo de dados, sendo que as suas vantagens podem ser encontradas em sistemas SQL e NoSQL, bem como distribuídos ou centralizados, tal como apresentado na secção de avaliação.As applications reach an wider audience that ever before, they must process larger and larger amounts of requests. In addition, they often must be able to serve users all over the globe, where network latencies have a significant negative impact on monolithic deployments. Therefore, distribution is a well sought-after solution to improve performance of both applicational and database layers. However, distributing data is not an easy task if we want to ensure strong consistency guarantees. This leads many databases systems to rely on expensive synchronization controls protocols such as two-phase commit, distributed consensus, distributed locking, among others, while other systems rely on weak consistency, unfeasible for some use cases. This thesis presents the design, implementation and evaluation of two solutions aimed at reducing the impact of ensuring strong consistency guarantees on database systems, especially geo-distributed ones. The first is the Primary Semi-Primary, a full replication distributed database architecture that allows different replicas to evolve independently, to avoid that clients wait for preceding non-conflicting updates. Al though replicas can process both reads and writes, improving scalability, the system still ensures strong consistency guarantees, by relaying transactions’ certifications to a central node. Its design is independent of the underlying data model, but its implementation can take advantage of the native concurrency control offered by some systems, as is exemplified by an implementation using PostgreSQL and its Snapshot Isolation. The results present several advantages in both throughput and response time, when comparing to other alternative architectures, in both local and geo-distributed environments. The second solution is the Multi-Record Values, a technique that dynami cally partitions numeric values into multiple records, allowing concurrent writes to execute with low conflict probability, reducing abort rate and/or locking contention. Lower limit guarantees, required by objects such as balances or stocks, are ensure by this strategy, unlike many other similar alternatives. Its design is also data model agnostic, given its advantages can be found in both SQL and NoSQL systems, as well as both centralized and distributed database, as presented in the evaluation section

Modelling geomechanics of residual soils with DMT tests

Tese de doutoramento. Engenharia Civil. Faculdade de Engenharia. Universidade do Porto, Universidade de Aveiro, Instituto Politécnico da Guarda. 200

Mechanical properties of phenine nanotubes

Phenine Nanotubes (PhNT) are cylinder-shaped molecules synthetized from 1,3,5-trisubstituted benzene ring building blocks that can form tubular segments of different sizes. Small nanotube segments have been recently synthetized, and efforts are being made to increase the nanotubes’ length by adding more “phenine” units. To the authors’ best knowledge, a complete characterization of the mechanical properties of these nanotubes has not yet been accomplished. In this work, Reax and AIREBO forcefields were used to model armchair and zigzag PhNTs and Molecular Dynamics simulations were employed to determine their mechanical properties for tensile, compressive, bending and twisting loadings. It was found that PhNTs have a much lower Young’s modulus (about 30%) and tensile strengths (about 45%) than carbon nanotubes (CNTs), but can endure longer tensile strains without breaking apart. Although possessing a lower bending and twisting stiffness than CNTs, PhNT have highly flexible sidewalls due to their superior porosity, and therefore can withstand higher angles of twist and angles of bend without breaking bonds. This extra flexibility; extended porosity; possibility for heteroatom doping and reasonable strength, make PhNTs very promising candidates for a wide range of applications, such as sensing, ionic transistors or molecular sieving. Finally, a brief study on the application of elastic continuum shell formulas to predict the critical stress (compression), critical moment (bending) and critical torque (twisting) is also presented

Instrumentação axial e radial em ensaios triaxiais no domínio das pequenas deformações

A maior parte das deformações dos solos ocorre para níveis de deformação entre 0.01 % a 0.5 %, tornando-se fundamental uma correcta caracterização do comportamento dos solos e geomateriais para este domínio de pequenas deformação. Para a determinação do comportamento geotécnico nestes domínios, é indispensável nos ensaios triaxiais a utilização de instrumentação local para a eliminação de erros derivados do efeito de confinamento do provete, de fenómenos de flexão e deformação do sistema de ensaio. Uma técnica de instrumentação eficaz e de baixo custo consiste na utilização de Local Deformation Transducer (LDT). Neste artigo apresenta-se a sua eficiência na monitorização de ensaios triaxiais monotónicos a trajectória controlada, e cíclicos, ilustrando-se métodos para o registo da deformação radia. São ainda ilustrados casos de estudo com o intuito de validar a sua eficiência, nomeadamente ensaios em trajectória de tensões controladas e ensaios cíclicos