Emergence and resilience of cooperation in the spatial Prisoner's Dilemma via a reward mechanism

We study the problem of the emergence of cooperation in the spatial Prisoner's Dilemma. The pioneering work by Nowak and May showed that large initial populations of cooperators can survive and sustain cooperation in a square lattice with imitate-the-best evolutionary dynamics. We revisit this problem in a cost-benefit formulation suitable for a number of biological applications. We show that if a fixed-amount reward is established for cooperators to share, a single cooperator can invade a population of defectors and form structures that are resilient to re-invasion even if the reward mechanism is turned off. We discuss analytically the case of the invasion by a single cooperator and present agent-based simulations for small initial fractions of cooperators. Large cooperation levels, in the sustainability range, are found. In the conclusions we discuss possible applications of this model as well as its connections with other mechanisms proposed to promote the emergence of cooperation

Lignes couplées à ondes lentes intégrées sur silicium en bande millimétrique - Application aux coupleurs, filtres et baluns

This work focuses on high-performances CS-CPW (Coupled Slow-wave CoPlanar Waveguide) transmission lines in classical CMOS integrated technologies for the millimiter-wave frequency band. First, the theory as well as the electrical models of the CS-CPW are presented. Thanks to the models and electromagnetic simulations, directional couplers with different coupling levels (3 dB, 10 dB, 18 dB) were designed in BiCMOS 55 nm technology. They have a good directivity, always better than 15 dB. A first prototype of a coupler was measured at 150 GHz presenting good agreement with the simulations. Next, coupled-line base filters were developed at 80 GHz using the CS-CPWs. Simulation present competitive results with the state-of-art: 11% of fractional bandwidth and a unload quality factor of 25. Finally, three projects started based on the CS-CPWs. The projects are currently used in two theses and one internship: a RTPS at 47 GHz, an isolator at 75 GHz and a balun at 80 GHz.L’objectif de ce travail de thèse est le développement en technologie intégrée standard d’une structure de ligne de transmission optimisée en termes de pertes, d’encombrement, de facteur de qualité et surtout du choix du niveau de couplage aux fréquences millimétriques. Cette structure a été nommée CS-CPW (Coupled Slow-wave CoPlanar Waveguide). Dans un premier temps, la théorie ainsi que les modèles électriques des CS-CPW sont présentés. Grâce aux modèles et aux simulations électromagnétiques, des coupleurs directionnels avec plusieurs valeurs de couplage (3 dB, 10 dB, 18 dB) ont été conçus en technologie BiCMOS 55 nm. Ils présentent tous une très bonne directivité, elle est toujours supérieure à 15 dB. Un premier prototype de coupleur a été mesuré à 150 GHz. Dans un deuxième temps, des filtres à la base des lignes couplées ont été développés à 80 GHz en utilisant des lignes CS-CPW. Les résultats des simulations présentent des résultats concurrentiels avec l’état de l’art : 11% de bande passante relative et un facteur non-chargé autour de 25. Finalement, trois projets ont démarré à la base de ces lignes. Ces projets sont actuellement utilisés dans deux travaux de thèse et un stage : un RTPS à 47 GHz, un isolateur à 75 GHz et un balun à 80 GHz

Application of self-healing materials in architecture and construction industry: an exploratory review

ARTÍCULO ESPECIALIZADO EN REVISTA INTERNACIONAL INDEXADAThis work’s aim was to perform a review of the scientific literature from the standpoint of both the architect and builder. In the first place, on which self-healing materials are currently available for construction industry; secondly, to acknowledge the main applications and the self-healing methods of each material. The review was largely carried out using the scientific database tool sciencedirect® and other similar tools on the main applications of self-healing materials in construction industry. The results reveal that the main applications refer to the production of self-healing concretes and mortars by means of self-healing techniques, for example: insertion of microcapsules with various self-healing agents, followed by self-healing bacteria. It is concluded that with the use of these materials not only does the service life of structures of buildings improves, but also that of the entire building, increasing durability and noticeably decreasing maintenance and reparation costs

Experimental Investigation of Propped Fracture Conductivity in Tight Gas Reservoirs Using The Dynamic Conductivity Test

Hydraulic Fracturing stimulation technology is used to increase the amount of oil and gas produced from low permeability reservoirs. The primary objective of the process is to increase the conductivity of the reservoir by the creation of fractures deep into the formation, changing the flow pattern from radial to linear flow. The dynamic conductivity test was used for this research to evaluate the effect of closure stress, temperature, proppant concentration, and flow back rates on fracture conductivity. The objective of performing a dynamic conductivity test is to be able to mimic actual field conditions by pumping fracturing fluid/proppant slurry fluid into a conductivity cell, and applying closure stress afterwards. In addition, a factorial design was implemented in order to determine the main effect of each of the investigated factors and to minimize the number of experimental runs. Due to the stochastic nature of the dynamic conductivity test, each experiment was repeated several times to evaluate the consistency of the results. Experimental results indicate that the increase in closure stress has a detrimental effect on fracture conductivity. This effect can be attributed to the reduction in fracture width as closure stress was increased. Moreover, the formation of channels at low proppant concentration plays a significant role in determining the final conductivity of a fracture. The presence of these channels created an additional flow path for nitrogen, resulting in a significant increase in the conductivity of the fracture. In addition, experiments performed at high temperatures and stresses exhibited a reduction in fracture conductivity. The formation of a polymer cake due to unbroken gel dried up at high temperatures further impeded the propped conductivity. The effect of nitrogen rate was observed to be inversely proportional to fracture conductivity. The significant reduction in fracture conductivity could possibly be due to the effect of polymer dehydration at higher flow rates and temperatures. However, there is no certainty from experimental results that this conductivity reduction is an effect that occurs in real fractures or whether it is an effect that is only significant in laboratory conditions

DIPLOMADO DE PROFUNDIZACION CISCO PRUEBA DE HABILIDADES PRÁCTICAS CCNP

Se realiza la topología indicada por las guías, con la utilización en la simulación de la aplicación GNS3 y sus componentes descargados como imágenes Switch y Router. Estas funciones se realizaron siguiendo las instrucciones según las guías, compuesto de dos momentos, siendo el primero un avance y este último el documento final. Además, cuenta con seis (6) puntos a desarrollar, de esta forma adquirir principalmente conocimientos de conmutación, enrutamiento de red, seguridad, administración entre otros. Palabras Clave: CISCO, CCNP, Conmutación, Enrutamiento, Redes, Electrónica.The topology indicated by the guides is carried out, with the use in the simulation of the GNS3 application and its downloaded components such as Switch and Router images. These functions were carried out following the instructions according to the guidelines, composed of two moments, the first being a preview and the latter the final document. In addition, it has six (6) points to develop, in this way to acquire mainly knowledge of switching, network routing, security, administration, among others. Keywords: CISCO, CCNP, Routing, Switching, Networking, Electronics

Dinâmica de produção de peixe ornamental do alto e médio rio Negro

This study aimed to analyze the changes in the production of ornamental fish in the area of Barcelos, primary fish trade place of the high and middle Rio Negro. For this, a survey of ornamental fish´s shipments in the local port was madden, through a review of the permanent production and local exportation records of the Piaba Project over the past decade. The predominant species at local ornamental fisheries was the Cardinal Tetra (Paracheirodon axelrodi), it contributed with 86% during the studied time. The rest of species locally called as “variedade” contributed with 14%, and it´s production remained relatively stable along the years. The most abundant species of the “variedade” group were: Hemigrammus bleheri (23.7%), Paracheirodon simulans (22%), Hyphessobrycon sp. "rosaceu" (8.9%l), Carnegiella spp. (7.4%), Carnegiella marthae (4.4%), Apistogramma spp. (4.1), Petitella georgiae (4%), Nannostomus eques (3.9%), Dicrossus filamentosus (2.5%), Hyphessobrycon socolofi (1.7%), Nannostomus marginatus (1.4%), Ancistrus cf. dolichopterus (1.4%), Nannostomus trifasciatus (1.4%), Hyphessobrycon copelandi (1.3%), Osteoglossum ferreirai (1.2%) and Hyphessobrycon erythrostigma (1%). Evidence was found about the hydrological cycle influenced the Monthly Total Production values and its composition, modifying the abundance of families. The influence was not decisive for all the years production, it suggests that in some years other unmeasured factors like trading factors could influenced the production in a bigger way.Este trabalho objetivou analisar as mudanças na produção de peixes ornamentais na área de Barcelos, principal local de comercialização dos peixes do alto e meio Rio Negro. Para isso foi realizado um levantamento dos embarques de peixes ornamentais no porto dessa cidade, por meio de uma revisão dos registros do acompanhamento permanente da produção e exportação local do Projeto Piaba na última década. A espécie predominante na produção pesqueira ornamental da região foi o cardinal (Paracheirodon axelrodi), contribuindo com 86% no período estudado. O resto de espécies conhecidas como variedade, contribuiu com 14%, mantendo uma produção relativamente estável ao longo dos anos. As espécies mais abundantes da variedade foram: Hemigrammus bleheri (23,7%), Paracheirodon simulans (22%), Hyphessobrycon sp. "rosacéu" (8,9%), Carnegiella spp. (7,4%), Carnegiella marthae (4,4%), Apistogramma spp. (4,1%), Petitella georgiae (4%), Nannostomus eques (3,9%), Dicrossus filamentosus (2,5%), Hyphessobrycon socolofi (1,7%), Nannostomus marginatus (1,4%), Ancistrus cf. dolichopterus (1,4%), Nannostomus trifasciatus (1,4%), Hyphessobrycon copelandi (1,3%), Osteoglossum ferreirai (1,2%) e Hyphessobrycon erythrostigma (1%). Encontrou-se evidência de que o ciclo hidrológico influenciou os valores de Produção Total Mensais e a sua composição, modificando a abundância das famílias. A influência na produção não foi determinante em todos os anos, isto sugere que em alguns anos outros fatores não medidos, como os comerciais, podem ter influenciado a produção em maior medida

Organizaciones que aprenden: Una perspectiva desde la interacción empresa-contexto

This article addresses the importance that organizations that learn to learn have in the current context, in a globalized world with constant changes that requires the process of knowledge acquisition, managerial transformation, to be at the forefront, achieve success and be a highly competitive organization, in the business reality of the 21st century. A theoretical analysis was carried out under a bibliographic design that allowed defining, describing and explaining, through deductive inference, organizations that learn to learn, the prevailing thinking of subjects and teams that learn in systemic organizations, change, complex contexts and the management of uncertainty as resources that potentiate learning, the construction of organizational knowledge and finally the approximate ways to learn and build knowledge. The final reflections as a conclusion reflect that the continuous creation of organizational knowledge is the key to ensure the evolution of the organization and ensures that the organization changes, transcends and evolves.El presente artículo aborda la importancia que tienen en el contexto actual las organizaciones que aprenden a aprender, en un mundo globalizado y de constantes cambios que exige el proceso adquisición de conocimiento, trasformación gerencial, para estar a la vanguardia, alcanzar el éxito y ser una organización altamente competitiva, en la  realidad empresarial del siglo XXI. Se llevó a cabo un análisis teórico bajo un diseño bibliográfico que permitió definir, describir y explicar, vía inferencia deductiva  las organizaciones que aprenden a aprender, el pensamiento prevaleciente de los sujetos y equipos que aprenden en las organizaciones sistémicas,  el cambio, los contextos complejos y la gestión de la incertidumbre como recursos que potencializan el aprendizaje, la construcción de conocimiento organizacional y finalmente las vías aproximativas para aprender y construir conocimiento. Las reflexiones finales a modo de conclusión reflejan que la creación continua  de conocimiento organizativo, es la clave para asegurar la evolución de la organización y  garantiza que la organización cambie, trascienda y  evolucione