911 resultados para Existence and multiplicity of solutions
Resumo:
This report concerns the provisions and practices on betting-related match fixing in sports
within the 28 Member States. Carried out in late 2013/early 2014, respondents in each Member
State reported on that state’s gambling-related provisions in respect of football and tennis and
(in each country) a third sport determined on the basis of either its popularity (in terms of
participation or television viewing) or the existence of betting-related “scandals” in that sport
within that particular jurisdiction. Those reports helped the authors to compare the Member
States’ regulatory and self-regulatory frameworks relating to risk assessment and conflict of
interest management, with a view to indicating areas of best practice, identifying particularly
good legislative frameworks and highlighting areas where change was either desirable or
necessary. While some individual Member States have legislation which might provide
templates that others could adapt for their own use, the authors were not convinced that “more
law”, whether at the national or European level, was desirable. Rather, more effective
cooperation among the stakeholders was identified as being more likely to provide tangible
benefits than would new legal frameworks.
Resumo:
This paper reports on a research project designed to discover what schools are teaching in Religious Education in Northern Ireland and what procedures are in place to maintain standards in the delivery of the subject. A search through literature shows that little research has been carried out to determine what is being taught in Religious Education in Northern Ireland. It also indicates that there are very weak systems of control to measure the effectiveness or quality of what is delivered. A survey of the websites of all Post-Primary schools in the region was used to provide some answers to the basic question of what is being taught in RE. Using content and discourse analysis of these alongside supporting documentary sources (textbooks and exam specifications), it is possible to get a clearer picture of how the Northern Ireland Core Syllabus for Religious Education and any additional curricular elements are delivered in schools. The findings show that a significant minority of schools do not publicly articulate what pupils do in religious education. In situations where the content of religious education is made clear, some definite trends are evident. Despite the existence of a statutory core syllabus, there is significant variation in what is taught in schools. The content is most divergent from the syllabus in relation to the teaching of World Religions at Key Stage 3 and at Key Stage 4 whole elements of the syllabus are neglected due to limited conformity between the syllabus and exam specifications. These results raise important questions about the systems of regulation and control of the subject in the region. In law the subject is exempt from formal inspection by the local inspection authority; instead, a form of inspection is allowed for by the Christian churches who design the syllabus, but it is a process that is either entirely neglected or entirely unreported in situations where it does occur. It is argued that these findings raise questions of more general concern for this and other regions in Europe where the teaching of religious education is largely unregulated. For example, to what extent should states take an interest in what is taught in religious education, how it is delivered, what values it promotes and how standards of teaching and learning in the subject are upheld?
Resumo:
The scale of the Software-Defined Network (SDN) Controller design problem has become apparent with the expansion of SDN deployments. Initial SDN deployments were small-scale, single controller environments for research and usecase testing. Today, enterprise deployments requiring multiple controllers are gathering momentum e.g. Google’s backbone network, Microsoft’s public cloud, and NTT’s edge gateway. Third-party applications are also becoming available e.g. HP SDN App Store. The increase in components and interfaces for the evolved SDN implementation increases the security challenges of the SDN controller design. In this work, the requirements of a secure, robust, and resilient SDN controller are identified, stateof-the-art open-source SDN controllers are analyzed with respect to the security of their design, and recommendations for security improvements are provided. This contribution highlights the gap between the potential security solutions for SDN controllers and the actual security level of current controller designs.
Control of ionization and dissociation of H2+ by elliptically polarized ultra-short VUV laser pulses
Resumo:
Resonance-enhanced multiphoton ionization of H2 + exposed to elliptically polarized VUV laser pulses is investigated. Differential cross sections for nuclei and electron are obtained using numerical solutions of the time-dependent Schrödinger equation. In this work in progress, we explore the dependence of the dissociative ionization observables with the polarization of the light.
Resumo:
The objective of this research was to design granulated iron oxide for the adsorption of heavy metals from wastewater. Polyvinyl acetate (PVAc) was chosen as a suitable binder; as it is water insoluble. Initial experiments on selection of suitable solvent of the polymer were carried out using three solvents namely; methanol, acetone and toluene. Based on the initial tests on product yield and mechanical strength, acetone was selected as the solvent for the polyvinyl acetate binder. Design of experiment was then used to investigate the influence of granulation process variables; impeller speed, binder concentration and liquid to solid ratio on the properties of the granular materials. The response variables in the study were granules mean size, stability in water and granule strength. The results showed that the combination of high impeller speed and high binder concentration favour the formation of strong and stable granules. Results also showed that leaching of the binder into the simulated was water was negligible. Trial adsorption experiments carried out using the strongest and most stable iron oxide granules produced in this work showed removal efficiency of around 70% of synthetic arsenic solutions with initial concentration of 1000 ppb.
Resumo:
This thesis presents the results of perturbed angular correlation (PAC) experiments , an experimental technique which measures the hyperfine interaction at probes (radioactive ions implanted in the materials to study), from which one infers local information on an atomic scale. Furthermore, abinitio calculations using density functional theory electronic obtain results that directly complement the experiments, and are also used for theoretical research. These methods were applied in two families of materials. The manganites, with the possible existence of magnetic, charge, orbital and ferroelectric orders, are of fundamental and technological interest. The experimental results are obtained in the alkaline-earth manganites (Ca, Ba, Sr), with special interest due to the structural variety of possible polymorphs. With probes of Cd and In the stability of the probe and its location in a wide temperature range is established and a comparison with calculations allows the physical interpretation of the results. Calculations of hyperfine properties in rare-earth manganites are also presented. The second type of materials in which hyperfine properties were studied are the Manganese pnictides: MnAs, MnSb, and MnBi, compounds in which magnetism is fundamental. The experimental results obtained mainly consider the MnAs compound, whose magneto-structural transition is of great interest. The transition is analyzed in detail with the local resolution characteristic of the technique, obtaining information of the character of the transition also with complementary, more conventional techniques. The last work in this thesis uses only the first principles calculations, continuing the theme of the hyperfine interactions, but this time with respect to ferroelectrics. Several transition metal oxides with perovskite or distorted structures are considered. The electric field gradient which exists due to the quadrupole interaction in nuclei is related to the spontaneous electric polarization, the main quantity measured in ferroelectrics. This study provides a fundamental theoretical basis for previous empirical studies, suggesting new directions for research in ferroelectrics and multiferroics using techniques which measure the electric field gradient.
Resumo:
In recent years, a new paradigm for communication called cooperative communications has been proposed for which initial information theoretic studies have shown the potential for improvements in capacity over traditional multi-hop wireless networks. Extensive research has been done to mitigate the impact of fading in wireless networks, being mostly focused on Multiple-Input Multiple-Output (MIMO) systems. Recently, cooperative relaying techniques have been investigated to increase the performance of wireless systems by using diversity created by different single antenna devices, aiming to reach the same level of performance of MIMO systems with low cost devices. Cooperative communication is a promising method to achieve high spectrum efficiency and improve transmission capacity for wireless networks. Cooperative communications is the general idea of pooling the resources of distributed nodes to improve the overall performance of a wireless network. In cooperative networks the nodes cooperate to help each other. A cooperative node offering help is acting like a middle man or proxy and can convey messages from source to destination. Cooperative communication involves exploiting the broadcast nature of the wireless medium to form virtual antenna arrays out of independent singleantenna network nodes for transmission. This research aims at contributing to the field of cooperative wireless networks. The focus of this research is on the relay-based Medium Access Control (MAC) protocol. Specifically, I provide a framework for cooperative relaying called RelaySpot which comprises on opportunistic relay selection, cooperative relay scheduling and relay switching. RelaySpot-based solutions are expected to minimize signaling exchange, remove estimation of channel conditions, and improve the utilization of spatial diversity, minimizing outage and increasing reliability.
Resumo:
Esta tese descreve uma framework de trabalho assente no paradigma multi-camada para analisar, modelar, projectar e optimizar sistemas de comunicação. Nela se explora uma nova perspectiva acerca da camada física que nasce das relações entre a teoria de informação, estimação, métodos probabilísticos, teoria da comunicação e codificação. Esta framework conduz a métodos de projecto para a próxima geração de sistemas de comunicação de alto débito. Além disso, a tese explora várias técnicas de camada de acesso com base na relação entre atraso e débito para o projeto de redes sem fio tolerantes a atrasos. Alguns resultados fundamentais sobre a interação entre a teoria da informação e teoria da estimação conduzem a propostas de um paradigma alternativo para a análise, projecto e optimização de sistemas de comunicação. Com base em estudos sobre a relação entre a informação recíproca e MMSE, a abordagem descrita na tese permite ultrapassar, de forma inovadora, as dificuldades inerentes à optimização das taxas de transmissão de informação confiáveis em sistemas de comunicação, e permite a exploração da atribuição óptima de potência e estruturas óptimas de pre-codificação para diferentes modelos de canal: com fios, sem fios e ópticos. A tese aborda também o problema do atraso, numa tentativa de responder a questões levantadas pela enorme procura de débitos elevados em sistemas de comunicação. Isso é feito através da proposta de novos modelos para sistemas com codificação de rede (network coding) em camadas acima da sua camada física. Em particular, aborda-se a utilização de sistemas de codificação em rede para canais que variam no tempo e são sensíveis a atrasos. Isso foi demonstrado através da proposta de um novo modelo e esquema adaptativo, cujos algoritmos foram aplicados a sistemas sem fios com desvanecimento (fading) complexo, de que são exemplos os sistemas de comunicação via satélite. A tese aborda ainda o uso de sistemas de codificação de rede em cenários de transferência (handover) exigentes. Isso é feito através da proposta de novos modelos de transmissão WiFi IEEE 801.11 MAC, que são comparados com codificação de rede, e que se demonstram possibilitar transferência sem descontinuidades. Pode assim dizer-se que esta tese, através de trabalho de análise e de propostas suportadas por simulações, defende que na concepção de sistemas de comunicação se devem considerar estratégias de transmissão e codificação que sejam não só próximas da capacidade dos canais, mas também tolerantes a atrasos, e que tais estratégias têm de ser concebidas tendo em vista características do canal e a camada física.
Resumo:
Tese de Doutoramento em Biologia, Especialidade em Biologia Molecular, Universidade do Algarve, 2008
Resumo:
Aggregation and fibrillation of proteins have a great importance in medicine and industry. Misfolding and aggregation are the basis of many neurodegenerative diseases like Alzheimer and Parkinson. Osmolytes are molecules that can accumulate within cells and act as protective agents and they can inclusively act as protein stabilizers when cells are exposed to stress conditions. Osmolytes can also act as protein stabilizers in vitro. In this work, two different proteins were studied, the ribosomal protein from Thermus thermophilus and the mouse prion protein. The existence of an unstructured N-terminal on the prion protein does not affect its stability. The effect of the osmolyte sucrose on the fibrillation and stabilization of these two proteins was studied through kinectic and equilibrium measurements. It was shown that sucrose is able to compact the native structure of S6 protein in fibrillization conditions. Sucrose affects also folding and unfolding kinetic of S6 protein, delaying unfolding and increasing folding rate constants. The mechanism of stabilization by sucrose is non-specific because it is distributed for all protein structure, as it was demonstrated by a protein engineering approach. Sucrose delays the process of formation and elongation of S6 and prion protein from mouse. This delay is the result of the compaction of the native structure refered above. However, cellular toxicity studies have shown that fibrils formed in the presence of sucrose are more toxic to neuronal cells.
Resumo:
First described more that 150 years ago, the systematics of the genera Geomalacus and Letourneuxia (Arionidae, Gastropoda, Pulmonata) is still challenging. The taxonomic classification of arionid species is based on extremely labile characters such as body size or color that depends both on diet and environment, as well as age. Moreover, there is little information on the genetic diversity and population structure of the Iberian slugs that could provide extra clues to disentangle their problematic classification. The present work uses different analytical tools such as habitat suitability (Ecological Niche Modeling - ENM), cytogenetic analysis and phylogeography to establish the geographical distribution and evolutionary history of these pulmonate slugs. The potential distribution of the four Geomalacus species was modeled using ENM, which allowed the identification of new locations for G. malagensis, including a first report in Portugal. Also, it was predicted a much wider distribution for G. malagensis and G. oliveirae than previously known. Classical cytogenetic analyses were assayed with reproductive and a novel use of somatic tissues (mouth and tentacles) returning the number of chromosomes for the four Geomalacus species and L. numidica (n = 31, 2n = 62) and the respective karyotypes. G. malagensis and L. numidica present similar chromosome morphologies and karyotypic formulae, being more similar to each other than the Geomalacus among themselves. We further reconstructed the phylogeny of the genera Geomalacus and Letourneuxia using partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) and the nuclear ribosomal small subunit (18S rRNA), and applied an independent evolutionary rate method, the indicator vectors correlation, to evaluate the existence of cryptic diversity within species. The five nominal species of Geomalacus and Letourneuxia comprise 14 well-supported cryptic lineages. Letourneuxia numidica was retrieved as a sister group of G. malagensis. G. oliveirae is paraphyletic with respect to G. anguiformis. According to our dating estimates, the most recent common ancestor of Geomalacus dates back to the Middle Miocene (end of the Serravallian stage). The major lineage splitting events within Geomalacus occurred during the dry periods of the Zanclean stage (5.3-3.6 million years) and some lineages were confined to more humid mountain areas of the Iberian Peninsula, which lead to a highly geographically structured mitochondrial genetic diversity. The major findings of this are the following: (1) provides updated species distribution maps for the Iberian Geomalacus expanding the known geographic distribution of the concerned species, (2) unravels the cryptic diversity within the genera Geomalacus and Letourneuxia, (3) Geomalacus oliveirae is paraphyletic with G. anguiformis and (4) Letourneuxia numidica is sister group of G. malagensis.
Resumo:
Bycatch and discards are a cause of great concern in commercial world fisheries, with important ecological, economic and conservation implications. With the recent inclusion of a discards ban (‘landing obligation’), in the reform of the EU CFP, these issues have gained a tremendous attention from the economic, scientific, political and social point of view. Demersal trawl fisheries off the southern coast of Portugal capture an extraordinary diversity of species and generate considerable amounts of bycatch and discards. Bycatch includes commercially valuable target-species and bycatch species with low or no commercial value, but the great majority consists of unmarketable species, that are discarded. Bony fishes are dominant in bycatch and discards and the most discarded are of low or no commercial value. The reasons for discarding are fundamentally economic in nature (lack of commercial value) for bycatch species, and legal and administrative (legal minimum landing size) for commercially important species. The study of the reproductive biology of Galeus melastomus, discarded by crustacean trawls, suggests that a minimum landing size should be established for this species, and explains the importance of such a study in the assessment and management of fisheries. The discovery of a new species of the ray Neoraja iberica n. sp. contributes to the knowledge of the local marine biodiversity in Portuguese waters and of the global marine biodiversity. The three cases of abnormal hermaphroditism recorded in Etmopterus spinax, are the first cases known to date of hermaphroditism in this species. There is a need to find solutions to the problem of bycatch and discards of trawl fisheries in the Algarve coast. A combination of technical, regulatory and economic measures to minimize bycatch and reduce discards, before implementing a ‘landing obligation’, is thought to be the best approach to apply in the southern Portuguese multispecies trawl fisheries.
Resumo:
Ce projet de travail est divisé en deux études principales: (a) l’influence des certains additifs organiques sur la consommation d’énergie et la pureté du métal de zinc déposé dans le processus d’extraction électrolytique, et (b) l’électrodéposition des alliages binaires et ternaires de Fe-Mo et Fe-Mo-P sur des substrats d’acier doux afin d’agir comme cathodes pour la production de chlorate. (a) Parmi les sept différents additifs organiques examinés, les sels des liquides ioniques ont réussi à augmenter le rendement du courant jusqu’à 95,1% comparé à 88,7% qui a obtenu à partir de l’électrolyte standard en présence des ions de Sb3+. La réduction maximale de la consommation d’énergie de ~173 kWh tonne-1 a été obtenue en ajoutant de 3 mg dm-3 du chlorure de 1-butyl-3-méthylimidazolium dans le même électrolyte. La teneur en plomb dans le dépôt de zinc est réduite de 26,5 ppm à 5,1-5,6 ppm en utilisant les sels des liquides ioniques. (b) Des différents binaires Fe-Mo et ternaires Fe-Mo-P alliages ont été électrodéposés sur des substrats d’acier doux. Les alliages préparés ont une tenure en Mo entre 21-47 at.% et une tenure en P de 0 à 16 at.%. L’activité électrocatalytique de ces alliages vers la réaction de dégagement d’hydrogène (RDH) a été étudiée dans des solutions de chlorure de sodium. La réduction maximale de la surtension de RDH de ~313 mV a été obtenue par l’alliage ternaire préparé Fe54Mo30P16 par rapport à celle obtenue pour l’acier doux. La rugosité de surface et l’activité intrinsèque des revêtements de Fe-Mo-P peuvent être l’origine du comportement prometteur de ces électrocatalyseurs vers la RDH.
Resumo:
This article focuses on the role played by principals in enhancing parental involvement in primary schools. The schools involved in this research were characterised by a high presence of ethnic minority children and were located in a neighbourhood of low social and economic status in the Midlands region of the United Kingdom. Qualitative methods were employed in order to explore the influence of strong leadership on engagement of the parents. The study spanned a period of four years, giving an opportunity to examine sustainability of the activities introduced by the principals and staff. The findings reported are based on data collected from an Infant and Junior School involved in a number of extra-curricular and curriculum-enhancing projects. It argues that strong leadership fosters engagement of parents in school activities and thus academic achievement of pupils improved over time. The findings bring evidence that the role of the school principal is crucial in the introduction, implementation and sustainability of solutions focused on parental involvement, as well as bringing benefits to the social cohesion of the local community. Full Text:
Resumo:
Global navigation satellite system (GNSS) receivers require solutions that are compact, cheap and low-power, in order to enable their widespread proliferation into consumer products. Furthermore, interoperability of GNSS with non-navigation systems, especially communication systems will gain importance in providing the value added services in a variety of sectors, providing seamless quality of service for users. An important step into the market for Galileo is the timely availability of these hybrid multi-mode terminals for consumer applications. However, receiver architectures that are amenable to high-levels of integration will inevitably suffer from RF impairments hindering their easy widespread use in commercial products. This paper studies and presents analytical evaluations of the performance degradation due to the RF impairments and develops algorithms that can compensate for them in the DSP domain at the base band with complexity-reduced hardware overheads, hence, paving the way for low-power, highly integrated multi-mode GNSS receivers.