Connectivity measures for internet topologies on the level of autonomous systems

Classical measures of network connectivity are the number of disjoint paths between a pair of nodes and the size of a minimum cut. For standard graphs, these measures can be computed efficiently using network flow techniques. However, in the Internet on the level of autonomous systems (ASs), referred to as AS-level Internet, routing policies impose restrictions on the paths that traffic can take in the network. These restrictions can be captured by the valley-free path model, which assumes a special directed graph model in which edge types represent relationships between ASs. We consider the adaptation of the classical connectivity measures to the valley-free path model, where it is -hard to compute them. Our first main contribution consists of presenting algorithms for the computation of disjoint paths, and minimum cuts, in the valley-free path model. These algorithms are useful for ASs that want to evaluate different options for selecting upstream providers to improve the robustness of their connection to the Internet. Our second main contribution is an experimental evaluation of our algorithms on four types of directed graph models of the AS-level Internet produced by different inference algorithms. Most importantly, the evaluation shows that our algorithms are able to compute optimal solutions to instances of realistic size of the connectivity problems in the valley-free path model in reasonable time. Furthermore, our experimental results provide information about the characteristics of the directed graph models of the AS-level Internet produced by different inference algorithms. It turns out that (i) we can quantify the difference between the undirected AS-level topology and the directed graph models with respect to fundamental connectivity measures, and (ii) the different inference algorithms yield topologies that are similar with respect to connectivity and are different with respect to the types of paths that exist between pairs of ASs.

Scalable model-based configuration management of security services in complex enterprise networks

Security administrators face the challenge of designing, deploying and maintaining a variety of configuration files related to security systems, especially in large-scale networks. These files have heterogeneous syntaxes and follow differing semantic concepts. Nevertheless, they are interdependent due to security services having to cooperate and their configuration to be consistent with each other, so that global security policies are completely and correctly enforced. To tackle this problem, our approach supports a comfortable definition of an abstract high-level security policy and provides an automated derivation of the desired configuration files. It is an extension of policy-based management and policy hierarchies, combining model-based management (MBM) with system modularization. MBM employs an object-oriented model of the managed system to obtain the details needed for automated policy refinement. The modularization into abstract subsystems (ASs) segment the system-and the model-into units which more closely encapsulate related system components and provide focused abstract views. As a result, scalability is achieved and even comprehensive IT systems can be modelled in a unified manner. The associated tool MoBaSeC (Model-Based-Service-Configuration) supports interactive graphical modelling, automated model analysis and policy refinement with the derivation of configuration files. We describe the MBM and AS approaches, outline the tool functions and exemplify their applications and results obtained. Copyright (C) 2010 John Wiley & Sons, Ltd.

The lipid composition of a cell membrane modulates the interaction of an antiparasitic peptide at the air-water interface

The antiparasitic property of peptides is believed to be associated with their interactions with the protozoan membrane, which calls for research on the identification of membrane sites capable of peptide binding. In this study we investigated the interaction of a lipophilicglutathioine peptide known to be effective against the African Sleeping Sickness (ASS - African Trypanosomiasis) and cell membrane models represented by Langmuir monolayers. It is shown that even small amounts of the peptide affect the monolayers of some phospholipids and other lipids, which points to a significant interaction. The latter did not depend on the electrical charge of the monolayer-forming molecules but the peptide action was particularly distinctive for cholesterol + sphingomyelin monolayers that roughly resemble rafts on a cell membrane. Using in situ polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS), we found that the orientation of the peptide is affected by the phospholipids and dioctadecyldimethylammonium bromide (DODAB), but not in monolayers comprising cholesterol + sphingomyelin. In this mixed monolayer resembling rafts, the peptide still interacts and has some induced order, probably because the peptide molecules are fitted together into a compact monolayer. Therefore, the lipid composition of the monolayer modulates the interaction with the lipophilic glutathioine peptide, and this may have important implications in understanding how the peptide acts on specific sites of the protozoan membrane. (C) 2011 Elsevier B.V. All rights reserved.

Argininosuccinate Synthetase Is a Functional Target for a Snake Venom Anti-hypertensive Peptide ROLE IN ARGININE AND NITRIC OXIDE PRODUCTION

Bj-BPP-10c is a bioactive proline-rich decapeptide, part of the C-type natriuretic peptide precursor, expressed in the brain and in the venom gland of Bothrops jararaca. We recently showed that Bj-BPP-10c displays a strong, sustained anti-hypertensive effect in spontaneous hypertensive rats (SHR), without causing any effect in normotensive rats, by a pharmacological effect independent of angiotensin-converting enzyme inhibition. Therefore, we hypothesized that another mechanism should be involved in the peptide activity. Here we used affinity chromatography to search for kidney cytosolic proteins with affinity for Bj-BPP-10c and demonstrate that argininosuccinate synthetase (AsS) is the major protein binding to the peptide. More importantly, this interaction activates the catalytic activity of AsS in a dose-dependent manner. AsS is recognized as an important player of the citrulline-NO cycle that represents a potential limiting step in NO synthesis. Accordingly, the functional interaction of Bj-BPP-10c and AsS was evidenced by the following effects promoted by the peptide: (i) increase of NO metabolite production in human umbilical vein endothelial cell culture and of arginine in human embryonic kidney cells and (ii) increase of arginine plasma concentration in SHR. Moreover, alpha-methyl-DL-aspartic acid, a specific AsS inhibitor, significantly reduced the anti-hypertensive activity of Bj-BPP-10c in SHR. Taken together, these results suggest that AsS plays a role in the anti-hypertensive action of Bj-BPP-10c. Therefore, we propose the activation of AsS as a new mechanism for the anti-hypertensive effect of Bj-BPP-10c in SHR and AsS as a novel target for the therapy of hypertension-related diseases.

Gerentes de projeto : um estudo sobre a relação entre perfis psicodemográficos, desempenho e progressão profissional

Dada a crescente estruturação das organizações permanentes em organizações temporárias, aqui representadas como projetos, há uma demanda proporcional por profissionais qualificados que atuem como os maestros dessas empreitadas – os gerentes de projetos (GP’s). Esta pesquisa de dissertação de mestrado tem por objetivo estudar como diferentes traços psicodemográficos, à saber: gênero, etnia, orientação sexual e aparência física, impactam na vida e na progressão profissional do GP que os detenha, pela perspectiva deste profissional. Na busca por possíveis respostas para essa questão, percorremos a teoria procurando os subsídios necessários ao GP para exercer satisfatoriamente sua atividade e ascender na carreira. Vimos que as hard skills desses profissionais são desenhadas e enriquecidas por meio das metodologias e boas práticas trazidas pelas diversas associações internacionais de gestão de projetos. Todavia, as ações prescritivas dessas metodologias apenas delineiam os contornos mais amplos das soft skills. Este conjunto de habilidades se mostrou fundamental para o GP em seu trabalho, sendo empiricamente apreendido e enriquecido pela experiência prática. Ademais, a progressão na carreira de GP é percebida frente à crescente complexidade dos projetos à ele subordinados, como também é percebida ao enveredar por caminhos mais estratégicos e menos operacionais. Calçamos a pesquisa sobre a cultura brasileira, usada como arcabouço para entender como tais profissionais exercem suas relações de liderança, comunicação, respeito e colaboração para com seus stakeholders, ou seja, suas soft skills, e orquestram as atividades necessárias para a conclusão satisfatória de um projeto. Sobre tal base, buscamos entender possíveis preconceitos e barreiras impostas às diferentes psicodemografias para, em sequência, observar quais impactos são percebidos pelos GP’s no exercício de suas atividades, bem como na progressão de suas carreiras. Trouxemos do campo entrevistas com vários GP’s de diferentes psicodemografias. A análise do discurso nos emprestou o ferramental para estudar os dados de campo, e abarcar conclusões sustentadas pela base teórica. Como resultado, percebemos que a cultura brasileira ainda apresenta mecanismos de dominação encarnados por um grupo androcêntrico, etnicamente branco e heterossexual, com prescrições e normas sobre a aparência física. Vimos também que as soft skills são influenciadas pela cultura local, principalmente quando são exercidas por minorias rejeitadas pelo grupo dominante. Percebemos a existência de portas e tetos de vidro na vida profissional de um GP que encarne determinados traços psicodemográficos, bem como uma introjeção de tal lógica androcêntrica. Tais profissionais exercem suas funções com um custo maior do que aquele realizado por homens, brancos, heterossexuais e de boa aparência, bem como precisam se mostrar resilientes à tal dominação. As barreiras para o gênero feminino também se erguem quando a GP mulher, mesmo em um contexto de liderança de uma organização temporária, exerce a maternidade.

Ampliando o acesso livre a informação: a digitalização do acervo do Núcleo Temático da Seca

FREIRE, Isa Maria, et al. Ampliando o acesso livre a informaçao: a digitalizaçao do acervo do Nucleo Tematico da Seca. Pesquisa Brasileira em Ciência da Informação e Biblioteconomia, v.3, n.2, p. 137-142, 2008.Disponivel em: . Acesso em: 04 nov. 2010.

Instituições, agricultura familiar e crédito rural: avaliação de resultados do Pronaf B nos territórios rurais do Rio Grande do Norte

Broadly anchored on Institutionalist literature this dissertation seeks to answer: Why rural credit granted to farming families in Rio Grande do Norte, Pronaf group B, has shown positive results in some territories while in others the same results are insatisfactory? Considering formal rules are the same, then why such results are so distinguished? This research supports the fact that these results are a direct consequence of the quality of institutions defined as longstanding social rules established and built in social interactions. For institutions one understands; organizational structures, formal and non-formal rules, social trust, thinking behaviors and its evolution as well as routines. Using Pronaf Rural Credit as a background this study measures and compares results obtained in the rural areas of Seridó, Sertão do Apodi, Mato Grande, Assú-Mossoró, Trairi, Potengi and Alto Oeste. The dimensions of measurement considered were: economics, social and guarantee of transparency. The study considers a sample of 402 Group B farming families. It also elaborates a socio-economic profile of these families in the considered areas and underlines the main causes for defaulted loans, difficulties to improve family income and results of access to Pronaf B credit line, as well as it proposes solutions to surpass obstacles to improve the efficiency of this credit line

Saberes da pesca: uma arqueologia da ciência da tradição

This essay presents and discusses knowledge obtained through tradition taken as knowledge built along generations, transmitted from mouth to mouth and everyday experiences result of a non-scientific knowledge based on observation and hints given by more experient generations. The referred icon used to develop such a discussion in this essay is fishing. We point out the knoledge which enables the fishermen, among other dominions, to: find out the fish and other animals feeding habits; find their way through by astral influence during night navigation and learn the tide flowing based on the moon cycle. On what comes to fishing knowledge, the research was organized based on a bibliographic study about several ways of fishing in the Northern, Northeastern, Southern and Southestern regions of Brazil. In the Northern and Northeastern regions, the field research was also focused. Having interviews, photographs and films as reference, this part of the research was divided into two parts: the first one situated in the Amazonian Region in na area called Baixo-Tocantins, in the State of Pará where we worked with fishermen in the small towns of Abaetetuba and Igarapé-Miri; and the second one was held in the Northeastern region of Brazil, in the State of Rio Grande do Norte, where we worked with fishermen on the Piató Lake, in the small city of Assú. We tarted discussing based on a descriptive study of the fishing techniques used, aiming to identify them as an ordered activity, differed and classified by knoledge obtained through the years, based on the relationship between man and Nature. Creativity, stimulated by human curiosity, is also discussed and shown as a result of various fishing journeys. The myths, as a component of the fishing world, especially those which describe the relationship between men and waters, also have an outstanding place. At last, two fishing techniques belonging to the research field reference, are also described and analysed under the focus of construction and systematization of the knowledge related to fishing. The theory approach is based on reflection upon the tradition knowledge discussed by Almeida (2001), Balandier (1997), Câmara Cascudo (1957, 2000, 2002) and Claude Lévi-Strauss (1976, 1987 and 1991). The essay is an exercise of knowledge production which defends the "relink" of knowledge, as Edgar Morin suggests when dealing with the sciences of complexity

Lagoa do Piató: a educação como uma obra de arte

A partir de una concepción de la educación como una obra de arte, la disertación revela los estudios realizados en una escuela de la comunidad de Areia Branca Piató, en la Laguna de Piató en Assú, Estado de Rio Grande do Norte. Como una forma de hacer dialogar conocimientos científicos y saberes tradicionales, la investigación establece el intercambio de saberes y afectos sobre todo por intermedio del intelectual de la tradición Francisco Lucas da Silva. Para construir un conocimiento pertinente (Edgar Morin), el que forma parte de un contexto, buscamos aquí la comprensión de una pedagogía viva e imaginativa. La disertación encontró en la Laguna un laboratorio vivo para pensar en una enseñanza educativa y para ejercer el pensamiento complejo. A partir de estudios e investigaciones anteriores, pude organizar lo que considero que se constituye como constelaciones de saberes que permiten dar continuidad a ese eje de investigación que empezó desde 1986 en el Grupo de Estudios de la Complejidad GRECOM. En la construcción de este trabajo, pude aprender valores que creo que son importantes para una educación compleja: la humildad delante de la vida; la abertura para diferentes lenguajes del mundo; el diálogo con la naturaleza; la apuesta en nuestras creencias; el sueño de resignificar a la realidad a partir del lazo entre la profundidad de nuestro ser y el mundo; el uso pleno de nuestras potencialidades imaginativas y creativas; y, finalmente, la vivencia intensa de los sentidos. Partiendo de ese aprendizaje, la investigación teórico‐práctica tuvo como elemento central el desarrollo de talleres sobre el tema del agua con alumnos de la enseñanza básicas de diversas series, y con la participación activa de dos profesoras de la comunidad de Areia Branca Piató. Fueron llevadas adelante experiencias que contemplaron una visión sistémica de la naturaleza, las fotografías, los atelieres, las clases de campo, el arte de educar, la narración de historias y sobre todo las enseñanzas del intelectual de la tradición Francisco Lucas da Silva

Os currículos praticados no cotidiano da EJA: regulações e emancipações na Escola Centro Educacional Dr. Pedro Amorim

This research has as its object of study practiced in the daily curriculum of Youth and Adults in their midst and considered discussion of the concepts of knowledge as regulation and emancipation. The camp of our research relates to the knowing / doing the teachers of this modality of education, in the Escola Centro Educacional Dr. Amorim-CEPA, the city of Assú/RN and is articulated to the emerging desire to understand how cooperating teachers have thought, organized and practiced the curriculum in order to consider the many complex situations that are present in everyday school life. Our tour was guided by the need to study the relationship between the regulated curriculum and practiced in everyday adult education, as well as to understand, from the knowing / doing of the teachers, the conceptions that guide their teaching practices and, therefore, reflect on this Reality curriculum in order to better signify then. In this sense, we turn to the fundamentals of qualitative research, adopting the procedures of documentary research, participant observation and semi-structured interview, which allowed us to enter a universe of complex dimensions, senses, and that add significant difference, because the forms of use of various practitioners are and unique, in that enroll in school life and define their brand identities. The predominance of a traditional teaching practice nature by a process of training and teaching experience, the lines of flight, volatilities and inventiveness promoted by the circumstances of everyday life are some of the conclusions we draw from the data collected. This reality, we infer that the practice of teachers varies between regulation and emancipation, being this time, many challenges to be faced, namely the process of continuing education, the conceptual understanding of the subject curriculum and the existence of relational different knowing / doing produced, used and created in/from the school routine of Youth and Adults

DERSU UZALA Hibridação Homem-Natureza

Esta disertación explora de qué forma las hibridaciones entre ser humano y ambientes naturales no urbanos contribuyen a configurar las estrategias de atención, de construcción de conocimiento y de interacción con el mundo del sujeto y cómo, recursivamente, las actitudes perceptivo-cognitivas y las maneras de acercarse a lo real, de imputar sentido a los fenómenos y de interactuar con el ambiente practicadas por el sujeto condicionan y contribuyen a definir las hibridaciones entre humanos y no humanos. Lo que guía esa exploración es el concepto de híbrido que, inspirándome en Bruno Latour (2008), concibo como una asociación entre elementos sin características inherentes, compenetrados, que se redefinen, recrean e reconfiguran recíprocamente. Utilizo como operadores cognitivos una narrativa literaria y una cinematográfica: el libro autobiográfico Dersu Uzala del escritor y explorador ruso Vladimir Klavdievich Arseniev (1872-1930), publicado por primera vez en 1923, y la película homónima del director japonés Akira Kurosawa (1910-1998), lanzada en 1975. Estas obras reconstruyen tres expediciones realizadas por Arseniev a principios del siglo XX en la región siberiana del Ussuri que tuvieron como guía al cazador nómada de etnia gold Dersu Uzala, con quien el escritor construyó una profunda amistad. La elección de hacer dialogar en el mismo plan a dos modos complementares de conocimiento, arte y ciencia, se fundamenta en la concepción de Edgar Morin (2003b) de la literatura y el cine como escuelas de vida y de complejidad humana y en la visión de Claude Lévi- Strauss (2007) del arte como modelo reducido que favorece una mirada más abarcadora sobre los fenómenos. Inicialmente, pongo en relación mi investigación con los trabajos de Silmara Lídia Marton (2008) y Samir Cristino de Souza (2009), que analizaron las estrategias de construcción de conocimiento y de interacción con el mundo de un habitante de la Laguna de Piató (Municipio de Assú, Estado de Rio Grande do Norte, Brasil), Francisco Lucas da Silva, y muestro algunas analogías entre estas y las de Dersu Uzala, ambas productos de determinadas hibridaciones con el ambiente. A continuación, exploro las implicaciones cognitivas de la amistad de Arseniev con el cazador gold, metáfora/encarnación del diálogo posible entre saberes de matrices diferentes. En un tercer momento, dialogando con pensadores que se interrogaron sobre el trinomio hombre-naturaleza-representaciones y con las narrativas de Arseniev (1997) y Kurosawa (1975), reflexiono sobre las ideas de híbrido, de humano y no humano, de vivo y no vivo, de proximidad y distancia del sujeto con respecto a otros sistemas de lectura del mundo, de relación directa y mediada con lo real, de ambientes naturales urbanos y no urbanos. A seguir, incursiono en el libro de Arseniev y en el largometraje de Kurosawa intentando identificar qué factores más contribuyeron para configurar las estrategias de conocimiento y de interacción con el ambiente manifestadas por el explorador y por el cazador gold y, recursivamente, de qué forma esas estrategias contribuyeron a definir sus hibridaciones con el ambiente siberiano. Por último, a partir de las reflexiones tejidas a lo largo del trabajo, me interrogo sobre lo que ellas pueden decirnos sobre nuestra forma de interactuar con la naturaleza no humana y sobre el diálogo entre distintas formas de percibir, conocer y relacionarse con el mundo

A prática de correção textual por professoras de língua portuguesa do ensino médio

Cette recherche analyse les pratiques de correction de textes de l'enseignement du 1, 2 et 3 ème niveau. Nous avons parti de discutions avec les professeurs de Langue Portugaise des troisièmes annèes d‟une école appartenant au enseignement publique, située à la ville d‟Assu RN. L'étude a les postulats théoriques de Cruz (2007), Dellagnelo (1998), Oliveira (2005), Pécora (1999), Ruiz (2001), Serafini (1989), et d‟autres. La méthodologie est de nature qualitative et d‟interpretation, dont le matériel a été constitué à partir des rapports des enseignants professionnels, ainsi que les 92 textes recueillies entre juillet et août 2008. Les dés montrent que la correction se configure comme un travail pratique, qui vise à aider les étudiants à améliorer leur écriture. Les professeurs font la correction d‟une forme mélangée, c'est-à-dire dans le texte apparaissent les corrections orthographiques, lexicales, etc., mais la prédominance de la correction est par rapport aux idées, pour le contenu du texte. Dans ce sens, les professeurs se rendent compte du valeur et de la hiérarchisation des idées discutées par les élèves, les reconnaître comme l'organisation de la sémantique et la séquence du texte. Tous les autres aspects (structurelles, grammaticaux) sont importants, cependant, en général, dans la pratique de correction des études, l‟exposition les idées occupent une place importante. Les marques de correction apparaissent sous la forme de petits billets, qui apprécie également toutes les étapes de l'écriture de texte

Representações discursivas de Ficar e Namorar em textos de vestibulandos e pré-vestibulandos

This doctoral thesis investigate the way vestibulandos and pré-vestibulandos construct their discursive representations of Ficar and Namorar in their textual production. At the same time, aims to discuss its implications for the ATD and for the teaching and learning of textual production in the context of Portuguese Language classes. Its theoretical framework is inspired mainly by three sources: textual linguistics, the textual analysis of discourses (ADAM, 2008), as well as by frames semantics (FILLMORE, 2006; FELTES, 2007). The methodology is based on a combination of qualitative and quantitative approaches (VIANNA et al., 2008). The data is composed of 168 empirical texts written by the vestibulandos of PSV/2005 da UFRN, Natal, RN, and by secondary school students who attended Escola Estadual Juscelino Kubitschek (EEJK), Assú, in the 2008 school year. The results indicate different categories of discursive representations of Ficar and Namorar , such as designation of referents, prediction, aspectualization, spatial-temporal circunstances , and metaphor, which reveal the influence of factors such as: the encyclopedic knowledge, the culture, as well as the cognitive components related to textual production. These results point out to the necessity of a teaching practice which enables the interaction among students, the discussion of current themes, as well as the student involvement with different textual genres, mainly the work with textual production in the classroom, so that it enables the students do acquire the textual production strategies. Thus, the overall goal is the (re)construction of their discursive representations, so that they can cope with new contexts of communicative interaction.

Molecular characterization of hemoglobin alpha-D chains from Geochelone carbonaria and Geochelone denticulata land turtles

In order to help elucidate the evolution of alpha-globins, the complete cDNA and amino acid sequences of Geochelone carbonaria and Geochelone denticulata land turtles alpha-D chains have been described. In G. carbonaria, the cDNA is 539 bp with ATG start codon located at position 46, TGA stop codon at position 469 and AATAAA polyadenylation signal at position 520. In G. denticulata, the cDNA is 536 bp with ATG start codon located at position 46, TGA stop codon at position 469 and AATAAA polyadenylation signal at position 517. Both cDNAs codify 141 amino acid residues, differing from each other in only four amino acid residues. When comparing with human Hb alpha-chain, alterations in important regions can be noted: alpha110 Ala-Gly, alpha114 Pro-Gly, alpha117 Phe-Tyr and alpha122 His-Gln. There is a high homology between the amino acids of these turtles when compared with chicken alpha-D chains, progressively decreasing when compared with human, crocodile, snake, frog and fish alpha-chains. Phylogenetic analysis of alpha-D chains shows that those of turtles are closer to those of birds than to snakes and lizards. (C) 2002 Elsevier B.V. All rights reserved.

The lipid composition of a cell membrane modulates the interaction of an antiparasitic peptide at the air-water interface

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