904 resultados para construction of imaginaries
Resumo:
Ireland’s remote position on the tip of Europe ensures that the country is vulnerable to uncertainty of supply. The reliance on conventional sources of electricity has ensured that escalated prices and high carbon emissions have been witnessed whilst opportunities that inherent resources provide, such as the wind, have not been capitalised upon. The intermittent nature of the wind make it difficult to maximise its potential as in many cases the highest wind speeds are highest when demand is low. The West of Ireland’s combination of wind speeds and unique topography makes it suitable for and innovative wind powered pumped storage system, which can essentially regulate the wind generated electricity and integrate further penetration of renewable energy. In addition, its location along the Atlantic Ocean provides further scope for innovation as seawater can be integrated into the system design. The construction of such an unprecedented project in combination with increased interconnectors has the potential to make Ireland a rechargeable battery for Europe. However, such ambitious plans are at the very early stages and are in direct contrast to current events in the Irish energy market. This study focuses on the feasibility of West of Ireland pumped storage systems. Entailed within this is an extensive desk study, a detailed site selection process and a feasibility study of grid connection. To increase opportunities to identify the best possible site, the feasibility study was focused on the Galway and Mayo areas solely.
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In this paper the construction of Reed-Solomon RS(255,239) codeword is described and the process of coding and decoding a message is simulated and verified. RS(255,239), or its shortened version RS(224,208) is used as a coding technique in Low-Power Single Carrier (LPSC) physical layer, as described in IEEE 802.11ad standard. The encoder takes 239 8-bit information symbols, adds 16 parity symbols and constructs 255-byte codeword to be transmitted through wireless communication channel. RS(255,239) codeword is defined over Galois Field GF and is used for correcting upto 8 symbol errors. RS(255,239) code construction is fully implemented and Simulink test project is constructed for testing and analyzing purposes.
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The construction of reservoirs is considered an important source of impacts on the fish fauna, severely altering the structure of the assemblage. This paper aimed to describe the structure of the fish assemblage of the Goioerê River, determining its longitudinal distribution and patterns of species dominance. The evaluation of its longitudinal variation in the diversity and abundance of the fish assemblage was conducted in July and October 2004 and January and May 2005. The collections were carried out near the headwaters (Gurucaia), middle stretch (Olaria), just above the falls (Paiquerê) and downstream (Foz). Forty-four species were captured. The Gurucaia fish assemblages differed significantly from Olaria, Paiquerê and Foz. The Olaria assemblages differed significantly from the Foz. Gurucaia showed the lowest diversity and abundance of species. Astyanax aff paranae Eigenmann,1914 (78% of the total) was found to be dominant at this site. Almost the same species richness was found at Olaria and Paiquerê, although Olaria had the greatest abundance of individuals. Astyanax aff paranae, Cyphocharax modestus (Fernández-Yépez, 1948) and Astyanax altiparanae Garutti & Britski, 2000 were the top three dominants and comprised over 71% of the total number of fish caught. At Paiquerê, Astyanax altiparanae, Hypostomus aff ancistroides (Ihering, 1911) and Loricariichthys platymetopon Isbrücker & Nijssen, 1979 composed 58% of the catches. Thirty-one species were recorded at Foz, which presented the greatest richness. The most abundant species were Apareiodon affinis (Steindachner, 1879), Galeocharax knerii (Steindachner, 1879) and A.altiparanae, which contributed to 50% of the total catches in this environment.These results record the fish biodiversity and how the community is longitudinally structured in the Goioerê River, and also demonstrate how this type of evaluation is important to understanding the fish community patterns and finding solutions to problems related to the conservation and management of the basin.
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ABSTRACT One of the most important effects derived from the intensive land use is the increase of nutrient concentration in the aquatic systems due to superficial drainage. Besides, the increment of precipitations in South America connected to the global climate change could intensify these anthropic impacts due to the changes in the runoff pattern and a greater discharge of water in the streams and rivers. The pampean streams are singular environments with high natural nutrient concentrations which could be increased even more if the predictions of global climate change for the area are met. In this context, the effect of experimental nutrient addition on macroinvertebrates in a lowland stream is studied. Samplings were carried out from March 2007 to February 2009 in two reaches (fertilized and unfertilized), upstream and downstream from the input of nutrients. The addition of nutrients caused an increase in the phosphorus concentration in the fertilized reach which was not observed for nitrogen concentration. From all macroinvertebrates studied only two taxa had significant differences in their abundance after fertilization: Corbicula fluminea and Ostracoda. Our results reveal that the disturbance caused by the increase of nutrients on the benthic community depends on basal nutrients concentration. The weak response of macroinvertebrates to fertilization in the pampean streams could be due to their tolerance to high concentrations of nutrients in relation to their evolutionary history in streams naturally enriched with nutrients. Further research concerning the thresholds of nutrients affecting macroinvertebrates and about the adaptive advantages of taxa in naturally eutrophic environments is still needed. This information will allow for a better understanding of the processes of nutrient cycling and for the construction of restoration measures in natural eutrophic ecosystems.
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We provide some guidelines for deriving new projective hash families of cryptographic interest. Our main building blocks are so called group action systems; we explore what properties of this mathematical primitives may lead to the construction of cryptographically useful projective hash families. We point out different directions towards new constructions, deviating from known proposals arising from Cramer and Shoup's seminal work.
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We first recall the construction of the Chow motive modelling intersection cohomology of a proper surface X and study its fundamental properties. Using Voevodsky's category of effective geometrical motives, we then study the motive of the exceptional divisor D in a non-singular blow-up of X. If all geometric irreducible components of D are of genus zero, then Voevodsky's formalism allows us to construct certain one-extensions of Chow motives, as canonical subquotients of the motive with compact support of the smooth part of X. Specializing to Hilbert-Blumenthal surfaces, we recover a motivic interpretation of a recent construction of A. Caspar.
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The long term goal of this research is to develop a program able to produce an automatic segmentation and categorization of textual sequences into discourse types. In this preliminary contribution, we present the construction of an algorithm which takes a segmented text as input and attempts to produce a categorization of sequences, such as narrative, argumentative, descriptive and so on. Also, this work aims at investigating a possible convergence between the typological approach developed in particular in the field of text and discourse analysis in French by Adam (2008) and Bronckart (1997) and unsupervised statistical learning.
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The main purpose of this work is to give a survey of main monotonicity properties of queueing processes based on the coupling method. The literature on this topic is quite extensive, and we do not consider all aspects of this topic. Our more concrete goal is to select the most interesting basic monotonicity results and give simple and elegant proofs. Also we give a few new (or revised) proofs of a few important monotonicity properties for the queue-size and workload processes both in single-server and multi- server systems. The paper is organized as follows. In Section 1, the basic notions and results on coupling method are given. Section 2 contains known coupling results for renewal processes with focus on construction of synchronized renewal instants for a superposition of independent renewal processes. In Section 3, we present basic monotonicity results for the queue-size and workload processes. We consider both discrete-and continuous-time queueing systems with single and multi servers. Less known results on monotonicity of queueing processes with dependent service times and interarrival times are also presented. Section 4 is devoted to monotonicity of general Jackson-type queueing networks with Markovian routing. This section is based on the notable paper [17]. Finally, Section 5 contains elements of stability analysis of regenerative queues and networks, where coupling and monotonicity results play a crucial role to establish minimal suficient stability conditions. Besides, we present some new monotonicity results for tandem networks.
Resumo:
The present thesis is a contribution to the debate on the applicability of mathematics; it examines the interplay between mathematics and the world, using historical case studies. The first part of the thesis consists of four small case studies. In chapter 1, I criticize "ante rem structuralism", proposed by Stewart Shapiro, by showing that his so-called "finite cardinal structures" are in conflict with mathematical practice. In chapter 2, I discuss Leonhard Euler's solution to the Königsberg bridges problem. I propose interpreting Euler's solution both as an explanation within mathematics and as a scientific explanation. I put the insights from the historical case to work against recent philosophical accounts of the Königsberg case. In chapter 3, I analyze the predator-prey model, proposed by Lotka and Volterra. I extract some interesting philosophical lessons from Volterra's original account of the model, such as: Volterra's remarks on mathematical methodology; the relation between mathematics and idealization in the construction of the model; some relevant details in the derivation of the Third Law, and; notions of intervention that are motivated by one of Volterra's main mathematical tools, phase spaces. In chapter 4, I discuss scientific and mathematical attempts to explain the structure of the bee's honeycomb. In the first part, I discuss a candidate explanation, based on the mathematical Honeycomb Conjecture, presented in Lyon and Colyvan (2008). I argue that this explanation is not scientifically adequate. In the second part, I discuss other mathematical, physical and biological studies that could contribute to an explanation of the bee's honeycomb. The upshot is that most of the relevant mathematics is not yet sufficiently understood, and there is also an ongoing debate as to the biological details of the construction of the bee's honeycomb. The second part of the thesis is a bigger case study from physics: the genesis of GR. Chapter 5 is a short introduction to the history, physics and mathematics that is relevant to the genesis of general relativity (GR). Chapter 6 discusses the historical question as to what Marcel Grossmann contributed to the genesis of GR. I will examine the so-called "Entwurf" paper, an important joint publication by Einstein and Grossmann, containing the first tensorial formulation of GR. By comparing Grossmann's part with the mathematical theories he used, we can gain a better understanding of what is involved in the first steps of assimilating a mathematical theory to a physical question. In chapter 7, I introduce, and discuss, a recent account of the applicability of mathematics to the world, the Inferential Conception (IC), proposed by Bueno and Colyvan (2011). I give a short exposition of the IC, offer some critical remarks on the account, discuss potential philosophical objections, and I propose some extensions of the IC. In chapter 8, I put the Inferential Conception (IC) to work in the historical case study: the genesis of GR. I analyze three historical episodes, using the conceptual apparatus provided by the IC. In episode one, I investigate how the starting point of the application process, the "assumed structure", is chosen. Then I analyze two small application cycles that led to revisions of the initial assumed structure. In episode two, I examine how the application of "new" mathematics - the application of the Absolute Differential Calculus (ADC) to gravitational theory - meshes with the IC. In episode three, I take a closer look at two of Einstein's failed attempts to find a suitable differential operator for the field equations, and apply the conceptual tools provided by the IC so as to better understand why he erroneously rejected both the Ricci tensor and the November tensor in the Zurich Notebook.
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Prof. Dr. Hugo de Souza Lopes is one of the authors of the phylogenetic classification of Sarcophagidae, especially Sarcophaginae. In this paper I present the taxonomic key of the tribes of Sarcophaginae according to his opinion; a list of the 48 genera and subgenera and the 356 species described by Prof. Lopes; and a review of subtribal construction of tribe Sarcophagini with a key of the subtribes. One new subtribe Boettcheriiscina Verves, subtr. nov. and two new monotypic genera (Mufindia Verves, gen. nov., and Sabiella Verves, gen. nov.) are described. The role of Prof. Lopes in the knowledge of taxonomy and ecology of American, Oriental, Australian and Oceanic Sarcophagidae is illumined.
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The spread of agrarian credit cooperativism in Spain (1890-1934) was done under a variety of ideological and economic orientations. This article focuses on the construction of a few tools and indicators to explain the characteristics of agricultural credit cooperatives. An analysis of financial operations of rural savings banks is related with socio-political aspects that influenced their development; This analysis helps us to explain the relative success of German credit cooperative models adopted in the context of Spanish agriculture, as happened on European periphery.
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Cette thèse explore les implications politiques de la montée en puissance des normes internationales sur nos sociétés contemporaines et pose la problématique des dynamiques participatives des représentants des consommateurs au sein des formes de pouvoir non étatique à l'aide du cas de l'Organisation internationale de normalisation (ISO). Le renforcement du pouvoir des normes internationales et autres spécifications techniques soulève d'importants enjeux démocratiques qui portent aussi bien sur la représentativité des acteurs qui les élaborent, sur l'articulation des prérogatives publiques et privées dans la gouvernance de la mondialisation, que sur le rôle de l'expertise dans la reconnaissance de ces nouvelles formes de pouvoir. La participation du monde associatif intervient sur ces différents enjeux de manière complexe. Cette recherche s'inscrit à la suite des études en relations internationales/économie politique internationale sur les formes d'autorité non étatique et s'inspire du concept de traduction issu de la sociologie des sciences et techniques pour mettre en lumière le rôle des spécifications techniques dans la construction d'une société de consommation centrée sur la liberté de choix et la façon dont les associations de consommateurs se saisissent des arènes de normalisation pour y faire valoir des préoccupations collectives, leur expertise et leur identité. Cette thèse défend l'idée que les consommateurs participent à la construction de l'autorité des normes internationales par leur rôle dans la traduction qui permet de relier les spécifications techniques au fonctionnement des marchés, au cadre réglementaire de la loi et aux préoccupations sociétales. L'analyse repose sur une observation ethnographique des délibérations d'un comité technique de l'ISO, une recherche-‐action, la réalisation d'entretiens et la consultation de documents d'archives de l'ISO. -- This thesis explores the political significance of the rise of international standards on contemporary societies and questions the participatory dynamics of consumers' representatives within nonstate forms of power, using the case of the International organization for standardization (ISO). The power granted to international standards and other technical specifications raises important democratic issues regarding the representativity of standard-‐ writers, the public-‐private relationships involved in this form of governance or the expertise sustaining the recognition of such new forms of power. The participation of civil society associations affect such issues in complex ways. This research relies on international relations/international political economy approaches of nonstate authority and takes inspiration from the concept of translation developed by science and technology studies to highlight the crucial role played by technical specifications in building a consumer society based on the freedom of choice as well as how consumers' associations take stock of standardization arenas to promote collective issues and claim their expertise and identity. This thesis argues that consumers contribute to the construction of the authority of international standards through their role in the translation that links international standards to the market society, the regulatory state as well as to societal preoccupation. The analysis is based on an ethnographic observation of deliberations within an ISO technical committee, a research-‐action, interviews as well as on the consultation of ISO archives.
Resumo:
The main goal of this article is to give an explicit rigid analytic uniformization of the maximal toric quotient of the Jacobian of a Shimura curve over Q at a prime dividing exactly the level. This result can be viewed as complementary to the classical theorem of Cerednik and Drinfeld which provides rigid analytic uniformizations at primes dividing the discriminant. As a corollary, we offer a proof of a conjecture formulated by M. Greenberg in hispaper on Stark-Heegner points and quaternionic Shimura curves, thus making Greenberg's construction of local points on elliptic curves over Q unconditional.
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Analysis of the genomes of schistosomes and one of their intermediate hosts, Biomphalaria glabrata, using Random Amplified Polymorphic DNA (RAPD) demonstrated that intraspecific genetic polymorphism in the parasite is limited but in the snail is highly pronounced. This suggests an important role for the snail in the determination of the epidemiology of the disease. In addition to their intraspecific stability, schistosome derived RAPDs exhibit a high level of interspecific polymorphism and are thus ideal for the construction of phylogenetic trees. For the detection of intraspecific polymorphisms extensive variation in the mitochondrial DNA is being exploited for the development of a PCR based test for Schistosoma mansoni. Gene level polymorphisms are being analyzed by Low Stringency Single Specific Primer PCR.
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This article addresses the normative dilemma located within the application of `securitization,’ as a method of understanding the social construction of threats and security policies. Securitization as a theoretical and practical undertaking is being increasingly used by scholars and practitioners. This scholarly endeavour wishes to provide those wishing to engage with securitization with an alternative application of this theory; one which is sensitive to and self-reflective of the possible normative consequences of its employment. This article argues that discussing and analyzing securitization processes have normative implications, which is understood here to be the negative securitization of a referent. The negative securitization of a referent is asserted to be carried out through the unchallenged analysis of securitization processes which have emerged through relations of exclusion and power. It then offers a critical understanding and application of securitization studies as a way of overcoming the identified normative dilemma. First, it examines how the Copenhagen School’s formation of securitization theory gives rise to a normative dilemma, which is situated in the performative and symbolic power of security as a political invocation and theoretical concept. Second, it evaluates previous attempts to overcome the normative dilemma of securitization studies, outlining the obstacles that each individual proposal faces. Third, this article argues that the normative dilemma of applying securitization can be avoided by firstly, deconstructing the institutional power of security actors and dominant security subjectivities and secondly, by addressing countering or alternative approaches to security and incorporating different security subjectivities. Examples of the securitization of international terrorism and immigration are prominent throughout.