7,327 research outputs found
The Penna model for biological ageing on a lattice: spatial consequences of child-care
We introduce a square lattice into the Penna bit-string model for biological
ageing and study the evolution of the spatial distribution of the population
considering different strategies of child-care. Two of the strategies are
related to the movements of a whole family on the lattice: in one case the
mother cannot move if she has any child younger than a given age, and in the
other case if she moves, she brings these young children with her. A stronger
condition has also been added to the second case, considering that young
children die with a higher probability if their mothers die, this probability
decreasing with age. We show that a highly non uniform occupation can be
obtained when child-care is considered, even for an uniform initial occupation
per site. We also compare the standard survival rate of the model with that
obtained when the spacial lattice is considered (without any kind of
child-care).Comment: 8 pages, 6 Postscript figure
Space-time Torsion and Neutrino Oscillations in Vacuum
The objective of this study is to verify the consistency of the prescription
of alternative minimum coupling (connection) proposed by the Teleparallel
Equivalent to General Relativity (TEGR) for the Dirac equation. With this aim,
we studied the problem of neutrino oscillations in Weitzenbock space-time in
the Schwarzschild metric. In particular, we calculate the phase dynamics of
neutrinos. The relation of spin of the neutrino with the space-time torsion is
clarified through the determination of the phase differences between spin
eigenstates of the neutrinos.Comment: 07 pages, no figure
Applications and Sexual Version of a Simple Model for Biological Ageing
We use a simple model for biological ageing to study the mortality of the
population, obtaining a good agreement with the Gompertz law. We also simulate
the same model on a square lattice, considering different strategies of
parental care. The results are in agreement with those obtained earlier with
the more complicated Penna model for biological ageing. Finally, we present the
sexual version of this simple model.Comment: For Int.J.Mod.Phys.C Dec. 2001; 11 pages including 6 fig
The importance of target audiences in the design of training actions
This paper describes the process of definition, conceptualization and implementation of a business course addressed for logistic and industrial managers. This course was designed using a blended methodology, with training in classroom, visits to enterprises and self- study, supported by an eLearning platform. The aim of this work is to create an opportunity to reflect about the decisions and strategies implemented and point future developments
Experimental characterization of the structural response of adobe arches
Earth was one of the first construction materials used by mankind and has been used as a building material since ancient times until the present days. Its qualities related to thermal comfort, low cost or simple construction techniques have contributed to such a long tradition throughout the world with several different architectural expressions, integrating the culture and history of each region.
With the wide propagation of steel and concrete structures, there has been a general loss of the traditional knowledge in earth construction. This type of construction presents important structural fragilities and requires a special maintenance to preserve its qualities. In order to understand the structural behaviour of this type of structures, the associated construction methods and processes have to be considered.
Aveiro University has been developing studies on adobe constructions, with research on the material mechanical characterization, experimental study of the structural behaviour of adobe masonry walls and, more recently, in the development of a detailed survey methodology for the characterization of buildings in Aveiro district.
Integrated in these studies, arches with different geometries were built using adobe blocks and traditional construction methods. These arches were tested under different types of vertical loading (distributed symmetrical, distributed non-symmetrical and point load) until collapse. The experimental tests performed reproduce the typical loading conditions of these structures during construction and use. The tests conducted, the results obtained and the main conclusions attained are described in this paper
Sympatric speciation in an age-structured population living on a lattice
A square lattice is introduced into the Penna model for biological aging in
order to study the evolution of diploid sexual populations under certain
conditions when one single locus in the individual's genome is considered as
identifier of species. The simulation results show, after several generations,
the flourishing and coexistence of two separate species in the same
environment, i.e., one original species splits up into two on the same
territory (sympatric speciation). As well, the mortalities obtained are in a
good agreement with the Gompertz law of exponential increase of mortality with
age.Comment: 5 pages including 3 encapsulated postscript (*.eps) figures; To
appear in European Physical Journal
Shear viscosity and nonlinear behaviour of whole blood under large amplitude oscillatory shear
We investigated experimentally the rheological behavior of whole human blood subjected to large amplitude oscillatory shear under strain control to assess its nonlinear viscoelastic response. In these rheological tests, the shear stress response presented higher harmonic contributions, revealing the nonlinear behavior of human blood that is associated with changes in its internal microstructure. For the rheological conditions investigated, intra-cycle strain-stiffening and intra-cycle shear-thinning behavior of the human blood samples were observed and quantified based on the Lissajous–Bowditch plots. The results demonstrated that the dissipative nature of whole blood is more intense than its elastic component. We also assessed the effect of adding EDTA anticoagulant on the shear viscosity of whole blood subjected to steady shear flow. We found that the use of anticoagulant in appropriate concentrations did not influence the shear viscosity and that blood samples without anticoagulant preserved their rheological characteristics approximately for up to 8 minutes before coagulation became significant
Tratamento de Infeções Protésicas com Desbridamento e Preservação do Implante - Resultados da Aplicação Prospetiva de um Protocolo Pré-estabelecido
Objetivo: O tratamento de infeções protésicas é complexo e os resultados do desbridamento com preservação da prótese são frequentemente imprevisíveis. A nossa hipótese é que é possível oferecer uma boa probabilidade de sucesso desde que sejam cumpridas algumas regras simples para correta seleção e tratamento dos doentes. O objetivo deste estudo é apresentar os resultados obtidos com a aplicação prospetiva desses pressupostos ao longo dos últimos anos na nossa instituição.
Material e Métodos: Trata-se de um estudo clínico prospetivo que inclui todos os doentes com infeção protésica tratados desde Janeiro/2012 e com um seguimento mínimo de 12 meses após o fim do tratamento. Apenas foram candidatos ao desbridamento com preservação do implante doentes com prótese estável, sem sinais de descolamento, boa condição de partes moles e curta duração dos sintomas. O desbridamento cirúrgico foi realizado pelo mesmo cirurgião e incluiu sempre troca de partes móveis. Sempre que possível a antibioterapia incluiu fármacos com eficácia para bactérias no biofilme.
Resultados: Foram estudados 24 doentes (15 joelhos e 9 ancas) com uma idade média de 65 anos. Um doente foi excluído da analise dos resultados por morte não relacionada. Registaram-se três casos de falência do tratamento o que resulta numa taxa de sucesso de 87% (20/23) com um seguimento médio de 30 meses após o término da antibioterapia.
Conclusão: A aplicação de um protocolo pré-estabelecido de tratamento permite a obtenção de bons resultados no tratamento de infeções protésicas mesmo quando se opte pela preservação do implanteinfo:eu-repo/semantics/publishedVersio
Some properties of two Nambu--Jona-Lasinio -type models with inputs from lattice QCD
We investigate the phase diagram of the so-called
Polyakov--Nambu--Jona-Lasinio (PNJL) model at finite temperature and nonzero
chemical potential. The calculations are performed in the light and strange
quark sectors (, , ), which includes the 't Hooft instanton induced
interaction term that breaks the axial symmetry, and the quarks are coupled to
the (spatially constant) temporal background gauge field. On one hand, a
special attention is payed to the critical end point (CEP). The strength of the
flavor-mixing interaction alters the CEP location, since when it becomes weaker
the CEP moves to low temperatures and can even disappear. On the other hand, we
also explore the connection between QCD, a nonlocal Nambu--Jona-Lasinio type
model and the Landau gauge gluon propagator. Possible links between the
quenched gluon propagator and low energy hadronic phenomenology are
investigated.Comment: Contribution to the International Meeting "Excited QCD", Peniche,
Portugal, 06 - 12 May 201
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