Monte Carlo Simulations of Sexual Reproduction

Modifying the Redfield model of sexual reproduction and the Penna model of biological aging, we compare reproduction with and without recombination in age-structured populations. In contrast to Redfield and in agreement with Bernardes we find sexual reproduction to be preferred to asexual one. In particular, the presence of old but still reproducing males helps the survival of younger females beyond their reproductive age.Comment: 8 pages, plain tex, 7 EPS figures, to appear in PHYSICA

Development of a build and deployment system

Tese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 200

Emergence of Hierarchy on a Network of Complementary Agents

Complementarity is one of the main features underlying the interactions in biological and biochemical systems. Inspired by those systems we propose a model for the dynamical evolution of a system composed by agents that interact due to their complementary attributes rather than their similarities. Each agent is represented by a bit-string and has an activity associated to it; the coupling among complementary peers depends on their activity. The connectivity of the system changes in time respecting the constraint of complementarity. We observe the formation of a network of active agents whose stability depends on the rate at which activity diffuses in the system. The model exhibits a non-equilibrium phase transition between the ordered phase, where a stable network is generated, and a disordered phase characterized by the absence of correlation among the agents. The ordered phase exhibits multi-modal distributions of connectivity and activity, indicating a hierarchy of interaction among different populations characterized by different degrees of activity. This model may be used to study the hierarchy observed in social organizations as well as in business and other networks.Comment: 13 pages, 4 figures, submitte

Communication of the nursing team and its relationship with management in health institutions

A comunicação deve acontecer constantemente a fim de reger as atividades gerenciais proporcionando informação, motivação e satisfação nos cargos. Tal estudo objetiva analisar as contribuições das pesquisas produzidas acerca da comunicação na gerência de enfermagem, tomando por base as publicações em periódicos nacionais. Trata-se de revisão integrativa da literatura, sendo incluídas dissertações, teses e artigos indexados na Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Medical Literature Analysis and Retrieval Systems Online (MEDLINE) e Banco de Dados Bibliográficos da Universidade de São Paulo (DEDALUS), no período de 1998 até 2008. O fortalecimento do processo comunicativo e a garantia de que ele ocorra de forma clara e eficiente é essencial para a gerência de enfermagem. É por meio desta comunicação eficiente que o enfermeiro garante identificação de problemas individuais e coletivos, podendo relacioná-los com a análise da situação encontrada e direcioná-los para um planejamento de cuidado apropriado e efetivo.La comunicación debe ocurrir constantemente, a fin de regir las actividades gerenciales, proporcionando información, motivación y satisfacción en las personas encargadas. Ese estudio tiene como objetivo analizar las contribuciones de las investigaciones producidas acerca de la comunicación en la gerencia de enfermería, basada en las publicaciones en periódicos brasileños. Esta es una Revisión Integradora de la Literatura que incluyó disertaciones, tesis y artículos indexados en los bancos de datos del Literatura de América Latina y del Caribe en las Ciencias de la Salud (LILACS), Medical Literature Analysis and Retrieval System Online (MEDLINE) y Base de datos bibliográfica de la Universidad de São Paulo (DEDALUS), entre 1998 y 2008. El fortalecimiento del proceso comunicativo y la garantía de que él ocurra de forma clara y eficiente es esencial para la gerencia de enfermería. Es por medio de esa comunicación eficiente que el enfermero garantiza la identificación de problemas individuales y colectivos, pudiendo relacionarles con el análisis de la situación encontrada y direccionarles hacia una planificación de cuidado apropiado y efectivo.Communication should occur constantly, in order to guide managerial activities, providing necessary information, motivation and satisfaction for people in charge. This study aims to analyze the contribution of researches produced on communication in nursing management, based on publications in Brazilian journals. Integrative Literature Review was used which included dissertations, theses and articles, indexed in Latin American and Caribbean Health Sciences (LILACS), Medical Literature Analysis and Retrieval System Online (MEDLINE) and Bibliographic Database of the University of São Paulo (DEDALUS), between 1998 and 2008. Strengthening the communication process and guaranteeing that it occurs in a clear and efficient way is essential for nursing management. Through this efficient communication nurses ensure the identification of individual and collective problems, thus being able to related them to the analysis of the found situation and direct them towards a planning of appropriate and effective care

Probing quantum fluctuation theorems in engineered reservoirs

Fluctuation Theorems are central in stochastic thermodynamics, as they allow for quantifying the irreversibility of single trajectories. Although they have been experimentally checked in the classical regime, a practical demonstration in the framework of quantum open systems is still to come. Here we propose a realistic platform to probe fluctuation theorems in the quantum regime. It is based on an effective two-level system coupled to an engineered reservoir, that enables the detection of the photons emitted and absorbed by the system. When the system is coherently driven, a measurable quantum component in the entropy production is evidenced. We quantify the error due to photon detection inefficiency, and show that the missing information can be efficiently corrected, based solely on the detected events. Our findings provide new insights into how the quantum character of a physical system impacts its thermodynamic evolution.Comment: 9 pages, 4 figure

Immunization and Aging: a Learning Process in the Immune Network

The immune system can be thought as a complex network of different interacting elements. A cellular automaton, defined in shape-space, was recently shown to exhibit self-regulation and complex behavior and is, therefore, a good candidate to model the immune system. Using this model to simulate a real immune system we find good agreement with recent experiments on mice. The model exhibits the experimentally observed refractory behavior of the immune system under multiple antigen presentations as well as loss of its plasticity caused by aging.Comment: 4 latex pages, 3 postscript figures attached. To be published in Physical Review Letters (Tentatively scheduled for 5th Oct. issue