From synchronization to multistability in two coupled quadratic maps

The phenomenology of a system of two coupled quadratic maps is studied both analytically and numerically. Conditions for synchronization are given and the bifurcations of periodic orbits from this regime are identified. In addition, we show that an arbitrarily large number of distinct stable periodic orbits may be obtained when the maps parameter is at the Feigenbaum period-doubling accumulation point. An estimate is given for the coupling strength needed to obtain any given number of stable orbits.Comment: 13 pages Latex, 9 figure

Stability Analysis of a Hybrid Cellular Automaton Model of Cell Colony Growth

Cell colonies of bacteria, tumour cells and fungi, under nutrient limited growth conditions, exhibit complex branched growth patterns. In order to investigate this phenomenon we present a simple hybrid cellular automaton model of cell colony growth. In the model the growth of the colony is limited by a nutrient that is consumed by the cells and which inhibits cell division if it falls below a certain threshold. Using this model we have investigated how the nutrient consumption rate of the cells affects the growth dynamics of the colony. We found that for low consumption rates the colony takes on a Eden-like morphology, while for higher consumption rates the morphology of the colony is branched with a fractal geometry. These findings are in agreement with previous results, but the simplicity of the model presented here allows for a linear stability analysis of the system. By observing that the local growth of the colony is proportional to the flux of the nutrient we derive an approximate dispersion relation for the growth of the colony interface. This dispersion relation shows that the stability of the growth depends on how far the nutrient penetrates into the colony. For low nutrient consumption rates the penetration distance is large, which stabilises the growth, while for high consumption rates the penetration distance is small, which leads to unstable branched growth. When the penetration distance vanishes the dispersion relation is reduced to the one describing Laplacian growth without ultra-violet regularisation. The dispersion relation was verified by measuring how the average branch width depends on the consumption rate of the cells and shows good agreement between theory and simulations.Comment: 8 pages, 6 figure

PROTOCOLO DE AVALIAÇÃO E CONTROLO DA DOR AGUDA NO DOENTE PEDIÁTRICO

INTRODUÇÃO: a prevenção, avaliação e controlo da dor em pediatria, pelas caraterísticas próprias dos seus utentes, constitui um desafio para os profissionais de saúde, pelo que constituímos uma equipa com a missão de elaborar um Protocolo de Orientação Clínica (POC) para a avaliação e controlo da dor aguda no doente pediátrico. OBJETIVOS: apresentar o percurso para elaboração e implementação do POC na instituição;divulgar alguns conteúdos do POC; apresentar resultados da última monitorização. MATERIAIS E MÉTODOS: constituiu-se uma equipa com médicos e enfermeiros, com representação de pediatria, anestesiologia, cirurgia e cuidados intensivos; foi elaborado e implementado o POC da dor aguda no doente pediátrico e efetuada monitorização dos registos. RESULTADOS: o POC apresenta as escalas de avaliação da dor, define critérios de seleção, metodologia de avaliação, registo de intensidade, intervenções farmacológicas e não farmacológicas e define estratégias de atuação em procedimentos dolorosos. Efetuada formação às diversas equipas médicas e de enfermagem e várias monitorizações pontuais. O início do registo informático aconteceu no dia 01/06/2013. O POC foi revisto em 2015. Efetuamos um levantamento retrospetivo dos registos da dor dos dias 4, 12, 20 e 28/01/2016 no Serviço de Cuidados Intensivos Pediátricos (SCIP) a um total de 29 crianças e no Serviço de Cuidados Intensivos Neonatais (SCIN) a um total de 79 recém-nascidos. Definimos 3 indicadores: (i) intervenção avaliar dor - no SCIP 93.3% das crianças tinham a intervenção programada e no SCIN 96.2%; (ii) avaliação da dor em 3 turnos nas 24h - no SCIP foi avaliada a dor a 66.8% das crianças e no SCIN a 90%; (iii) intensidade da dor - no SCIP 29.6% das crianças tiveram dor ligeira, 22.2% moderada e 11.1% intensa, no SCIN 78.9% tiveram dor ligeira e 12.7% moderada. Relativamente às escalas utilizadas verificamos que no SCIP a FLACC-R foi aplicada a 38.4% das crianças, a EDIN a 30.8%, a FLACC a 15.4% e Escalas de Autoavaliação a 15.4%. No SCIN, a 95.9% das crianças foi aplicada a escala de EDIN e a 4.1% a N-PASS. CONCLUSÃO: A avaliação e controlo da dor aguda é uma mais valia para a instituição e para as crianças/família a quem disponibiliza cuidados de saúde. Embora não tenhamos crianças com dor muito intensa, os resultados encontram-se aquém das expectativas, contudo, resultam do percurso efetuado e revelam potencial para desenvolver este projeto de melhoria da qualidadeinfo:eu-repo/semantics/draf

Modulation of gene expression in ex vitro grapevine (Vitis vinifera L.) by hormonal, oxidant and anti-oxidant stimuli

When in vitro plantlets developed under low light conditions are exposed to high light upon transfer to ex vitro, it is common to observe symptoms of oxidative stress. In order to unravel more of what takes place in this phase of transition, paramount for plant survival, the present study focused on the expression of genes coding for proteins related with the metabolic pathways most affected upon transfer to ex vitro and monitored their expression in response to hormones and chemicals inducing alternative sinks for photosynthetic electron transport (PET) and reactive oxygen species (ROS) production. The expression of eight genes was significantly downregulated after all the treatments: catalase, beta-glucosidase, cytochrome P450, vegetative storage protein 2, wak1, a calcium binding protein, a meprin and TRAF homology domain-containing protein and a serine/threonine kinase. It was possible to verify that abscisic acid (ABA) was able to revert light induced gene expression and that the PET inhibitors DCMU and DPI had the same effect as ABA. ABA and jasmonic acid showed parallel effects, as both induced the expression of the same set of genes. Finally, exogenous cytokinin, instead of enhancing the plant´s response to high light led to the downregulation of light-responsive genes

Soft singularity and the fundamental length

It is shown that some regular solutions in 5D Kaluza-Klein gravity may have interesting properties if one from the parameters is in the Planck region. In this case the Kretschman metric invariant runs up to a maximal reachable value in nature, i.e. practically the metric becomes singular. This observation allows us to suppose that in this situation the problems with such soft singularity will be much easier resolved in the future quantum gravity then by the situation with the ordinary hard singularity (Reissner-Nordstr\"om singularity, for example). It is supposed that the analogous consideration can be applied for the avoiding the hard singularities connected with the gauge charges.Comment: 5 page

Stratification of the orbit space in gauge theories. The role of nongeneric strata

Gauge theory is a theory with constraints and, for that reason, the space of physical states is not a manifold but a stratified space (orbifold) with singularities. The classification of strata for smooth (and generalized) connections is reviewed as well as the formulation of the physical space as the zero set of a momentum map. Several important features of nongeneric strata are discussed and new results are presented suggesting an important role for these strata as concentrators of the measure in ground state functionals and as a source of multiple structures in low-lying excitations.Comment: 22 pages Latex, 1 figur

Análise cariológica e molecular de Proechimys Allen, 1899 (Rodentia, Echimyidae) da região Amazônica

Karyologic and molecular analyses were carried out in Proechimys quadruplicatus and two other Proechimys species from the northern bank of the Rio Negro, Brazil. Analyses of cytb DNA sequence data and karyologic attributes partially sustained the goeldii species group. Molecular analyses grouped the two Proechimys sp. A haplotypes here sequenced with other specimens from the Amazonian region of Brazil and Venezuela, suggesting that they belonged to a single taxon. The three specimens of Proechimys sp. B also formed a monophyletic group. Proechimys sp. A,Proechimys sp. B, and P. guyannensis were grouped by karyologic and/or molecular data indicating that they are very similar one another and belong to the same species group, the guyannensis group. Phylogeographic analyses showed a high geographic structuration in the Proechimys sp. A population and the presence of a median vector between haplotypes of different rivers suggested that the large Amazonian rivers are barrier to these population.Análises cariológicas e moleculares foram realizadas em Proechimys quadruplicatus e duas outras espécies de Proechimys da margem norte do rio Negro, Brasil. Análises da seqüência de ADN do citocromo b e dos atributos cariológicos sustentam parcialmente o grupo de espécies goeldii. As análises moleculares agruparam os dois haplótipos de Proechimys sp. A aqui seqüenciados com outros espécimes da região Amazônica do Brasil e Venezuela sugerindo que eles pertençam ao mesmo táxon. Os três espécimes de Proechimys sp. B formam um grupo monofilético. Proechimys sp. A, Proechimys sp. B e P. guyannensis se agrupam pelos dados moleculares e/ou cariológicos indicando que eles são bastantes similares e pertencem ao mesmo grupo de espécies, o grupoguyannenis. A análise filogeográfica mostrou um padrão de estruturação geográfica forte nas populações de Proechimys sp. A, e a presença de vetores médios entre os haplótipos de diferentes rios, na análise de “median - joining”, sugere que estes rios sejam barreiras para estas populações