How Complex, Probable, and Predictable is Genetically Driven Red Queen Chaos?

Coevolution between two antagonistic species has been widely studied theoretically for both ecologically- and genetically-driven Red Queen dynamics. A typical outcome of these systems is an oscillatory behavior causing an endless series of one species adaptation and others counter-adaptation. More recently, a mathematical model combining a three-species food chain system with an adaptive dynamics approach revealed genetically driven chaotic Red Queen coevolution. In the present article, we analyze this mathematical model mainly focusing on the impact of species rates of evolution (mutation rates) in the dynamics. Firstly, we analytically proof the boundedness of the trajectories of the chaotic attractor. The complexity of the coupling between the dynamical variables is quantified using observability indices. By using symbolic dynamics theory, we quantify the complexity of genetically driven Red Queen chaos computing the topological entropy of existing one-dimensional iterated maps using Markov partitions. Co-dimensional two bifurcation diagrams are also built from the period ordering of the orbits of the maps. Then, we study the predictability of the Red Queen chaos, found in narrow regions of mutation rates. To extend the previous analyses, we also computed the likeliness of finding chaos in a given region of the parameter space varying other model parameters simultaneously. Such analyses allowed us to compute a mean predictability measure for the system in the explored region of the parameter space. We found that genetically driven Red Queen chaos, although being restricted to small regions of the analyzed parameter space, might be highly unpredictable.

Analysis of the clonal relationship among clinical isolates of Salmonella enterica serovar Infantis by different typing methods

Salmonella Infantis has been the second most common serovar in Argentina in the last two years, being isolated mostly from paediatric hospitalised patients. In order to determine the clonal relationship among Salmonella Infantis strains, we examined 15 isolates from paediatric patient faeces in Argentina (12 geographically related and 3 geographically non-related) by using antimicrobial susceptibility, plasmid profiling, repetitive extragenic palindromic (REP) PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR, and low-frequency restriction analysis of chromosomal DNA by pulsed field gel electrophoresis (PFGE). Four Spanish strains were included as controls of clonal diversity in molecular techniques. Antibiotype and plasmid profile was not useful as epidemiological tools. PFGE and REP-PCR were able to discriminate between Argentinean and Spanish isolates of Salmonella Infantis allowing to detect genetically related strains in three different cities. This finding indicates that a possible spread of a clone of this serovar in the North-eastern Region of Argentina has taken place in 1998.

À la búsqueda de la ciência política tomasiana. En torno al libro IV del "de regimine principum"

pp. 73-85

Unusual morphologies of Cryptococcus spp. in tissue specimens: report of 10 cases

Ten cases of cryptococcosis due to unusual microscopic forms of Cryptococcus sp. observed over a twenty-eight year period (1981-2009) are presented. The most important clinicopathological and laboratory data are tabulated. The uncommon forms of cryptococcal cells given are: structures resembling germ tube (one case), chains of budding yeasts (one case), pseudohyphae (two cases) and nonencapsulated yeast-like organisms (eight cases). The diagnosis was based on the histopathological findings. The causative organism was isolated and identified in seven cases; five were due to C. neoformans, and two to C. gattii. In addition, the importance of using staining histochemical techniques - Grocott's silver stain (GMS), Mayer's mucicarmine stain (MM) and Fontana-Masson stain (FM) - in the diagnosis of cryptococcosis is argued.

Population and railways in Portugal, 1801-1930

Portuguese historiography has mostly adopted a pessimistic view regarding the contribution of the railways to the development of country. Yet, railway access helped to increase population concentration and economic development, favoring migration into towns, the growth of pre-existing urban centers, and the emergence of new centers. But railways tended to be more beneficial to regions that were already prosperous and to aggravate the conditions unfavorable to development in areas with greater structural weaknesses.

Caminhos de ferro, população e desigualdades territoriais em Portugal, 1801-1930

A historiografia sobre os caminhos de ferro em Portugal tem analisado o seu impacto no país como um todo, dando pouca atenção à sua influência na dinâmica populacional. Este artigo defende que os caminhos de ferro estimularam o crescimento da população nas áreas servidas por esta infraestrutura, contribuíram para o desenvolvimento urbano e incentivaram as migrações internas. Porém, os seus efeitos foram desiguais, pois a ferrovia beneficiou as zonas já prósperas (Norte Atlântico), tendo uma influência negativa em regiões com maiores debilidades estruturais (Norte Interior). Além disso, não foi capaz de atrair uma significativa população migrante.

Abordagem integrada na análise química de amostras ambientais

Dissertação para obtenção do Grau de Doutor em Química

Estudo preliminar da variação dos níveis de cortisol em doentes da espécie Canis familiaris sujeitos a mastectomia por doença oncológica da mama

Dissertação de Mestrado Integrado em Medicina Veterinária

Obstrucao Coronaria apos Implante por Cateter de Protese Valvar Aortica

Fundamentos: O implante por cateter de bioprótese valvar aórtica (TAVI) consolidou-se como alternativa para o tratamento de pacientes com estenose aórtica importante de alto risco cirúrgico. Contudo, há poucos dados na literatura com respeito à obstrução coronária que, apesar de rara, trata-se de grave complicação do TAVI. Objetivo: Avaliar, no contexto brasileiro, a presença dessa importante complicação. Métodos: Foram avaliados todos os casos de obstrução coronária incluídos no Registro Brasileiro de TAVI. Foram coletados dados clínicos, do procedimento, do manejo e de evolução intra-hospitalar. Resultados: Entre 418 pacientes consecutivos do registro, ocorreram três casos de obstrução coronária (incidência de 0,72%). Em sua totalidade, os pacientes eram do sexo feminino, sem cirurgia de revascularização miocárdica (CRM) prévia, com idade média de 85 ± 3 anos, EuroSCORE logístico de 15 ± 6% e STS de 9 ± 4%. Todos os casos foram realizados com a válvula balão-expansível Sapien XT. Em um dos pacientes, com dados de tomografia computadorizada pré-procedimento, verificaram-se origem das artérias coronárias baixa e seio de Valsalva estreito. Todos os pacientes apresentaram-se clinicamente com hipotensão importante e mantida, imediatamente após o implante da válvula, e, apesar de angioplastia com implante de stent, todos os pacientes foram a óbito, sendo dois periprocedimento e um durante hospitalização. Conclusão: A obstrução coronária como complicação do TAVI, apesar de rara, é potencialmente fatal, podendo ocorrer mais frequentemente em mulheres e com as próteses expansíveis por balão. Fatores anatômicos podem estar relacionados com sua ocorrência, ressaltando-se a importância de boa avaliação pré-procedimento no sentido de evitar essa grave complicação.

The Phenomenon of international new ventures, global start-ups, and born-globals: what do we know after a decade (1993-2002) of exhaustive scientific inquiry?

In this paper, 27 studies from the last decade which deal more or less explicitly with the International New Venture, global start-up or born-global phenomenon are first identified, and then fully examined and critically assessed as a basis for obtaining an adequate view of the state-of-the-art of this increasingly important research avenue in the field of International Entrepreneurship (IE). The methodology used for this synthetic review allow us to analyze a number of recent, purposefully-chosen studies that are systematically compared along the following criteria: 1) main objective and type of research; 2) theoretical framework/s of reference, 3) methodological issues, and 4) main findings and/or conclusions. As a result of this literature review, a critical assessment follows in which the most relevant benefits and contributions as well as potential drawbacks, limitations or major discrepancies in the research activities conducted so far are discussed. Finally, some suggestions and implications are provided in the form of future research directions.

Caracterización de las empresas que colaboran con centros tecnológicos

En este trabajo procedemos a caracterizar las empresas que colaboran con centros tecnológicos. Las investigaciones empíricas de Cassiman & Veugelers (1998b) y Bayona (2000), junto a los enfoques teóricos del cambio tecnológico y de las motivaciones para colaborar tecnológicamente, serán los principales referentes para la formulación de hipótesis acerca del perfil de las empresas que colaboran con centros tecnológicos. Los datos procedentes de la Encuesta sobre Estrategias Empresariales de 1998 serán utilizados para elaborar el perfil de empresa – usuario y aportar así algunas intuiciones sobre las motivaciones específicas en la selección de un centro tecnológico en lugar de un cliente o un proveedor para una colaboración tecnológica. La búsqueda de recursos públicos y servicios tecnológicos concretos, así como una mayor confianza, parecen motivar la elección de dicha institución para colaborar en una alianza tecnológica.

Collaboration strategies and technological innovation: a contractual perspective of the relationship between firms and techonological centers

In this paper, a theoretical framework for analyzing the selection of governance structures for implementing collaboration agreements between firms and Technological Centers is presented and empirically discussed. This framework includes Transaction Costs and Property Rights’ theoretical assumptions, though complemented with several proposals coming from the Transactional Value Theory. This last theory is used for adding some dynamism in the governance structure selection. As empirical evidence of this theoretical explanation, we analyse four real experiences of collaboration between firms and one Technological Center. These experiences are aimed to represent the typology of relationships which Technological Centers usually face. Among others, a key interesting result is obtained: R&D collaboration activities do not need to always be organized through hierarchical solutions. In those cases where future expected benefits and/or reputation issues could play an important role, the traditional more static theories could not fully explain the selected governance structure for managing the R&D relationship. As a consequence, these results justify further research about the adequacy of the theoretical framework presented in this paper in other contexts, for example, R&D collaborations between firms and/or between Universities or Public Research Centers and firms.

The Cost of ownership in the governance of interfirm collaborations

This paper investigates the selection of governance forms in interfirm collaborations taking into account the predictions from transaction costs and property rights theories. Transaction costs arguments are often used to justify the introduction of hierarchical controls in collaborations, but the ownership dimension of going from “contracts” to “hierarchies” has been ignored in the past and with it the so called “costs of ownership”. The theoretical results, tested with a sample of collaborations in which participate Spanish firms, indicate that the cost of ownership may offset the benefits of hierarchical controls and therefore limit their diffusion. Evidence is also reported of possible complementarities between reputation effects and forms of ownership that go together with hierarchical controls (i.e. joint ventures), in contrast with the generally assumed substitutability between the two.

Alimentación, beneficencia y condiciones de vida en la industrialización: Olot, siglos XIX-XX

El renovado interés por el estudio de los niveles de vida en las investigaciones de Economía e Historia Económica, ha devuelto la atención de estas disciplinas al que debería ser su último referente. El desarrollo de aquel campo de estudio, además, ha reforzado las conexiones de aquellos ámbitos del conocimiento con otras ciencias, y esta circunstancia ha fomentado la formulación de nuevas preguntas y perspectivas analíticas. Esto es consecuencia del interés que tradicionalmente ha tenido entre muchos historiadores el estudio de los niveles de vida de la población, y de las diversas aportaciones que se han realizado sobre distintos aspectos de la misma variable, especialmente desde finales del siglo XIX, desde las ciencias sociales, experimentales o de la salud. El presente estudio se enmarca en esta problemática y responde, concretamente, a dos de los principales objetivos que guían el grupo de investigación. De un lado, aproximarnos al estudio de los niveles de vida a partir de casos singulares bien definidos, que ayuden a determinar mejor las diferentes variables que condicionaron su evolución y los cambios experimentados en sus mutuas relaciones. Del otro, elaborar un marco analítico más general, mediante la comparación de aquellos casos, que permita explicar más claramente cómo se alteraron algunos parámetros básicos de los niveles de vida con la expansión de la sociedad de mercado.