Nonlinear evolution of r-modes: the role of differential rotation

Recent work has shown that differential rotation, producing large scale drifts of fluid elements along stellar latitudes, is an unavoidable feature of r-modes in the nonlinear theory. We investigate the role of this differential rotation in the evolution of the l=2 r-mode instability of a newly born, hot, rapidly rotating neutron star. It is shown that the amplitude of the r-mode saturates a few hundred seconds after the mode instability sets in. The saturation amplitude depends on the amount of differential rotation at the time the instability becomes active and can take values much smaller than unity. It is also shown that, independently of the saturation amplitude of the mode, the star spins down to rotation rates that are comparable to the inferred initial rotation rates of the fastest pulsars associated with supernova remnants. Finally, it is shown that, when the drift of fluid elements at the time the instability sets in is significant, most of the initial angular momentum of the star is transferred to the r-mode and, consequently, almost none is carried away by gravitational radiation.Comment: 10 pages, 5 figure

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

Crossing steam and media literacy at preschool and primary school levels: Teacher training, workshop planning, its implementation, monitoring and assessment

Seventeen workshops on STEAM and Media Literacy, involving 500 children aged 3-10, their families and other community members, in a pandemic context, was the end result of the third phase of the ‘Digital Citizenship Academy’. This community-based action research project began in early 2015, in a Lisbon neighbourhood of Portugal. The workshops were planned, implemented, monitored and assessed by 29 teachers during an online training initially planned to be developed on site. Despite the Covid-19 outbreak, teachers implemented strategies to overcome the lack of resources and autonomy of many students, especially younger ones, and the training focus remained on the production of scientific, artistic, technological, but also media content. The workshops allowed the creation of media and STEAM products primarily focused on the arts, but in which science, technology, engineering and mathematics were present. Results point to the fact that STEAM projects gain in relevance when associated with Media Literacy activities, and vice versa. Although there is a general feeling that the situation resulting from the pandemic prevented the achievement of more significant results, the training course was suitable to pedagogical practices, provided an opportunity for sharing of experiences, practices and ideas, fostered cooperation and interdisciplinary, and resulted in useful resources.info:eu-repo/semantics/publishedVersio

A segurança e a defesa no ciberespaço

ResPublica : Revista Lusófona de Ciência Política, Segurança e Relações InternacionaisO aumento constante do número e do tipo das ameaças e das suas manifestações através de infiltrações deliberadas contra o aparelho dos Estados tem obrigado a dispor de ferramentas tecnológicas especializadas que possam detetar e bloquear o crescente número de ciberataques e o identificar da sua natureza disruptiva e transnacional. Pretende-se com este artigo contribuir para a restauração da inicial utilização livre da internet, cuja atividade normal e segurança não poderão continuar comprometidas em nenhum dispositivo ou componente da sua rede global Perante o emergir de novos riscos e da insegurança crescente, e porque se encontra em causa a defesa da inerente soberania nacional, os Estados têm de continuar a envidar esforços e recursos no sentido de conjugarem as suas abordagens à problemática da prevenção de ciberataques de ordem disruptiva, que colocam em causa e em permanência o normal funcionamento das infraestruturas críticas, as capacidades de Intelligence, as redes de Aviso e os sistemas de Segurança e Defesa Nacionais.The steady increase in the number and type of threats and its manifestations through deliberate infiltration against the States structures, have required to create specialized technological tools with the capacity to detect and block the increasing number of cyber attacks and able to identify its disruptive and transnational nature. This article is intended to contribute to the restoration of the Internet initial free use, whose normal activity and security must be assured any time in any device of its global network. Face to the emergence of new risks and growing insecurity, and because this matter afects the national sovereignty defence, all States must continue to make efforts and resources in order to combine their approach to the problem of the prevention of cyberattacks, much of them disruptive; type of atacks that all times may put in danger the normal functioning of critical infrastructure, the Intelligence capabilities and the National Security and Defense system

Sacrococcygeal teratoma with malignant transformation in an adult female: CT and MRI findings

This report describes a case of sacrococcygeal teratoma with adenocarcinomatous transformation in a 45-year-old woman. This is an infrequent location for teratoma in adults and malignant transformation has rarely been described. Prognosis depends on complete excision. Clinical manifestations, imaging aspects and histological findings of this case are presented. CT and MRI adequately document the mixed cystic and solid nature of the tumour, its extension and relations with adjacent structures, allowing accurate pre-operative planning

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

COPD and cardiovascular disease

COPD is one of the major public health problems in people aged 40 years or above. It is currently the 4th leading cause of death in the world and projected to be the 3rd leading cause of death by 2020. COPD and cardiac comorbidities are frequently associated. They share common risk factors, pathophysiological processes, signs and symptoms, and act synergistically as negative prognostic factors. Cardiac disease includes a broad spectrum of entities with distinct pathophysiology, treatment and prognosis. From an epidemiological point of view, patients with COPD are particularly vulnerable to cardiac disease. Indeed, mortality due to cardiac disease in patients with moderate COPD is higher than mortality related to respiratory failure. Guidelines reinforce that the control of comorbidities in COPD has a clear benefit over the potential risk associated with the majority of the drugs utilized. On the other hand, the true survival benefits of aggressive treatment of cardiac disease and COPD in patients with both conditions have still not been clarified. Given their relevance in terms of prevalence and prognosis, we will focus in this paper on the management of COPD patients with ischemic coronary disease, heart failure and dysrhythmia.Novartis Portugal Novartisinfo:eu-repo/semantics/publishedVersio

Rubinstein Taybi Syndrome. A Case Report

Os autores descrevem um caso de Síndrome de Rubinstein-Taybi em que as características faciais e os polegares alargados permitiram o diagnóstico na primeira semana de vida. Salientam na evolução as infecções respiratórias de repetição, o atraso psicomotor e estaturo ponderal. Discutem as prováveis formas de transmissão deste síndrome

População de afídeos de cereais de inverno em Coxilha/RS, dados de 2013-2014.

Orientador: Douglas Lau