Stability properties of divergence-free vector fields

A divergence-free vector field satisfies the star property if any divergence-free vector field in some C1-neighborhood has all singularities and all periodic orbits hyperbolic. In this paper we prove that any divergence-free vector field defined on a Riemannian manifold and satisfying the star property is Anosov. It is also shown that a C1-structurally stable divergencefree vector field can be approximated by an Anosov divergence-free vector field. Moreover, we prove that any divergence-free vector field can be C1-approximated by an Anosov divergence-free vector field, or else by a divergence-free vector field exhibiting a heterodimensional cycle.Comment: 24 page

Sobre a fotografia de Fernando Lemos

Sublinha-se muitas vezes a dimensão representativa na fotografia, sobretudo pelo seu valor instrumental, mas a fotografia nunca se libertou da tensão existente entre representação, por um lado, e expressão na imagem, por outro, de um tempo fixado (em sentido histórico e material) e de um tempo a ser criado. Essa tensão é inerente à técnica fotográfica e aos objectos por ela produzidos e é sobre ela que se traça a divisão entre diferentes práticas fotográficas, por exemplo, a distinção entre usos artísticos e outros. As fotos de Fernando Lemos (produzidas no conjunto a que nos referimos entre 1949-1952) serão aqui analisadas como objectos para pensar esta tensão

Antoni Muntadas : on translation : the audience : the publication + the picture collection

O texto analisa a intervenção de Muntadas, The Picture Collection. Partindo da operacionalização de imagens de arquivo, o artista interpela o espectador na sua relação com os modos de produção/distribuição dos mass media e da arte

Confidence regions for variance components using inducing pivot variables

The goal of this paper is to present what we think to be an interesting development of the concept of pivot variable. The inducing pivot variables induce probability measures which may be used to carry out inference. As illustration of this approach we will show how to obtain confidence intervals for the variance components of mixed linear models.info:eu-repo/semantics/publishedVersio

Linear and quadratic sufficiency and commutativity

Given a mixed model let T be the orthogonal projection matrix on the range space spanned by the mean vector. [...]info:eu-repo/semantics/publishedVersio

Comparison of environmental impacts of municipal waste before and after the introduction of PAYT systems using life cycle assessment: the cases of Aveiro, Larnaka and Lisbon

PAYT-Tool to Reduce Waste in South Europe LIFE15 ENV/PT/000609N/

Development of indicators to monitor environmental impacts of the transition to PAYT tariffs

Project LIFE PAYT – Tool to reduce waste in South Europe (LIFE 15 ENV/PT/000609). Co-funded by the LIFE programme of the European Commissioninfo:eu-repo/semantics/publishedVersio

Co-working spaces in Porto, Portugal: collaborative economy within capitalism reforms or anti-capitalist experiences?

Co-working spaces are collaborative economic practices that have been gaining increasing visibility in the last decade in European cities. In Porto, these practices are currently quite popular. In this research, the authors map and characterize co-working spaces in Porto, aiming to analize their spatial distribution and perceptions, motivations and opinions of their owners / managers. Based on content analysis of web sites and three semi-structured interviews with managers and owners of co-working spaces, we propose in this article a new approach to the subject, in order to understand which dimensions of capitalism profit orientation; organizational structure; professional autonomy and responsibility; organizational responsibility are transformed or abolished in these economic activities

A criança hiperativa e seu corpo: estudo clínico sobre a gênese da hiperatividade em crianças

A group of 22 hyperactive children from 7 to 12 years of age was selected among 38 out-patients registered at Hospital do Servidor Público de São Paulo (Civil Servant Hospital of the State of São Paulo). Their psychiatric evaluation was negative, the neurological examination showed psychomotor syndrome, and psychological evaluation revealed disorders related with Ego maturation in all cases. Although all children were referred to psychotherapy, only thirteen underwent individual sessions once a week for an uninterrupted period of up to one year. Neither diets nor medicines were prescribed. After six months and one year of treatment, the children were reevaluated. They showed improved school performance, reduced hyperactivity, and better internal psychic organization. These results are considered as undeniable evidence of the psychodynamic origin of hyperactivity syndrome in children, when no definite neurologic or psychiatric diseases are demonstrated.Vinte e duas crianças hiperativas, de 7 a 12 anos de idade foram selecionadas dentre 38 matriculadas no Ambulatório de Psiquiatria do Hospital do Servidor Público do Estado de São Paulo. A avaliação psiquiátrica foi negativa, o exame neurológico revelou síndrome psicomotora, a avaliação psicológica evidenciou transtornos relacionados com maturação do Ego em todos os casos. Encaminhadas à psicoterapia, apenas 13 crianças puderam atender a sessões individuais e semanais, por um período ininterrupto de seis meses a um ano. Nem dietas nem medicamentos foram prescritos. Reavaliação feita após seis meses e um ano, revelou redução da hiperatividade, aumento do rendimento escolar e melhor organização psíquica interna. Estes resultados são considerados forte evidência da origem psicodinâmica da síndrome hiperativa em crianças neurologicamente normais.Federal University of São Paulo Head of the Neuropsychology Unit Institute of PsychologySão Paulo Catholic University Psychologist in the São Paulo Public Servant Hospital Infant Clinical PsychologyUNIFESP, Head of the Neuropsychology Unit Institute of PsychologySciEL