Self-organized patterns of coexistence out of a predator-prey cellular automaton

We present a stochastic approach to modeling the dynamics of coexistence of prey and predator populations. It is assumed that the space of coexistence is explicitly subdivided in a grid of cells. Each cell can be occupied by only one individual of each species or can be empty. The system evolves in time according to a probabilistic cellular automaton composed by a set of local rules which describe interactions between species individuals and mimic the process of birth, death and predation. By performing computational simulations, we found that, depending on the values of the parameters of the model, the following states can be reached: a prey absorbing state and active states of two types. In one of them both species coexist in a stationary regime with population densities constant in time. The other kind of active state is characterized by local coupled time oscillations of prey and predator populations. We focus on the self-organized structures arising from spatio-temporal dynamics of the coexistence. We identify distinct spatial patterns of prey and predators and verify that they are intimally connected to the time coexistence behavior of the species. The occurrence of a prey percolating cluster on the spatial patterns of the active states is also examined.Comment: 19 pages, 11 figure

Simulación de procesos de forja axisimétrica mediante el método de los elementos finitos: un modelo sencillo de rozamiento

Se presenta en este artículo un método sencillo de modelización del r.ozamiento en la simulación de procesos de forja axisimétrica mediante el Método de los Elementos Finitos (MEF). Tras una breve descripción de la formulación básica de flujo, se revisan las alternativas inás comunes para la consideración del fenómeno del rozamiento y se describe el método SMM (Stiffness Matrix Method), utilizado para tener en cuenta la fricción. Se presenta finalmente un ejemplo industrial que muestra el buen comportamiento de dicho método aplicado a la formulación de flujo.Peer Reviewe

Simulación de procesos de forja axisimétrica mediante el método de los elementos finitos: un modelo sencillo de rozamiento

Se presenta en este artículo un método sencillo de modelización del r.ozamiento en la simulación de procesos de forja axisimétrica mediante el Método de los Elementos Finitos (MEF). Tras una breve descripción de la formulación básica de flujo, se revisan las alternativas inás comunes para la consideración del fenómeno del rozamiento y se describe el método SMM (Stiffness Matrix Method), utilizado para tener en cuenta la fricción. Se presenta finalmente un ejemplo industrial que muestra el buen comportamiento de dicho método aplicado a la formulación de flujo.Peer Reviewe

Neonatal Diagnosis of Prader-Willi Syndrome

A síndrome de Prader-Willi tem uma prevalência aproximada de 1:25000 nascimentos. No período neonatal há hipotonia severa, atraso de crescimento e dificuldade alimentar que persistem durante o primeiro ano de vida. O quadro clínico inicial contrasta com a bulimia que se evidencia mais tarde e que, não controlada, pode conduzir à obesidade mórbida. Descrevem-se as características clínicas, o diagnóstico genético e os cuidados específicos a ter na promoção da saúde a propósito de cinco crianças com síndrome de Prader Willi, cujo diagnóstico foi feito no período neonatal

Boundary layers in pressure-driven flow in smectic A liquid crystals

This article examines the steady flow of a smectic A liquid crystal sample that is initially aligned in a classical "bookshelf" geometry confined between parallel plates and is then subjected to a lateral pressure gradient which is perpendicular to the initial local smectic layer arrangement. The nonlinear dynamic equations are derived. These equations can be linearized and solved exactly to reveal two characteristic length scales that can be identified in terms of the material parameters and reflect the boundary layer behavior of the velocity and the director and smectic layer normal orientations. The asymptotic properties of the nonlinear equations are then investigated to find that these length scales apparently manifest themselves in various aspects of the solutions to the nonlinear steady state equations, especially in the separation between the orientations of the director and smectic layer normal. Non-Newtonian plug-like flow occurs and the solutions for the director profile and smectic layer normal share features identified elsewhere in static liquid crystal configurations. Comparisons with numerical solutions of the nonlinear equations are also made

The effectiveness and impact on performance of pharmacy-related competency development frameworks: A systematic review and meta-analysis

BACKGROUND: Competency frameworks for education, training and development are widely used in the health professions, including pharmacy. Published studies suggest that competency frameworks have an impact on professional performance. Professional performance that is consistent with up-to-date knowledge and skills influences health care quality and patient safety. This review assessed the effectiveness of competency frameworks in facilitating improvement in pharmacists' performance. METHOD: PubMed/Medline, CINAHL, Embase, ERIC, PsycINFO and Scopus electronic databases were searched to identify relevant literature. The findings of the included studies were synthesised qualitatively, and via a meta-analysis. The meta-analysis evaluated the odds of improved competency behaviour as a proxy measure of impact on pharmacists' performance. Study quality was assessed using 12 criteria adapted from the EPPI-Centre guidelines v0.9.7. The protocol for this review is registered on PROSPERO with reference number CRD42018096580. RESULTS: In total, nine interventional studies were identified for review. The review findings showed observable and significant improvement in pharmacists' performance when competency frameworks are used to appraise performance, identify knowledge gaps, and tailor learning activities. A meta-analysis that involved a total of 348 pharmacists undergoing repeat peer assessment showed pooled odds for improved competency behaviour of 4.41 (95% CI: 1.89-10.29, I2 = 83%). Subgroup analyses showed pooled odds with corresponding 95% CI of 6.50 (1.77-23.97, I2 = 77%) vs 2.95 (0.59-14.72, I2 = 93%) for the studies that were conducted in countries within or outside Europe, respectively; 10.51 (3.73-29.62, I2 = 24%) vs 2.39 (0.96-5.95, I2 = 87%) for studies with reassessment conducted at ≤6 months from baseline, or more, respectively; 6.68 (1.63-27.45, I2 = 88%) vs 2.80 (0.86-9.07, I2 = 74%) for studies involving hospital or community pharmacists, respectively; and 2.80 (1.22-6.45, I2 = 77%) for studies with low risk of bias. CONCLUSION: These findings suggest competency frameworks facilitate improvement in pharmacists' performance; however, further evaluative studies are needed

Sialic Acid Utilisation and Synthesis in the Neonatal Rat Revisited

Background: Milk is the sole source of nutrients for neonatal mammals and is generally considered to have co-evolved with the developmental needs of the suckling newborn. One evolutionary conserved constituent of milk and present on many glycoconjugates is sialic acid. The brain and colon are major sites of sialic acid display and together with the liver also of synthesis. Methodology/Principal Findings: In this study we examined in rats the relationship between the sialic acid content of milk and the uptake, utilization and synthesis of sialic acid in suckling pups. In rat milk sialic acid was found primarily as 39sialyllactose and at highest levels between 3 and 10 days postpartum and that decreased towards weaning. In the liver of suckling pups sialic acid synthesis paralleled the increase in milk sialic acid reaching and keeping maximum activity from postnatal day 5 onwards. In the colon, gene expression profiles suggested that a switch from sialic acid uptake and catabolism towards sialic acid synthesis and utilization occurred that mirrored the change of sialic acid in milk from high to low expression. In brain sialic acid related gene expression profiles did not change to any great extent during the suckling period. Conclusions/Significance: Our results support the views that (i) when milk sialic acid levels are high, in the colon this sialic acid is catabolized to GlcNAc that in turn may be used as such or used as substrate for sialic acid synthesis and (ii) when milk sialic acid levels are low the endogenous sialic acid synthetic machinery in colon is activated