Hamiltonian elliptic systems: a guide to variational frameworks

Consider a Hamiltonian system of type $$-\Delta u=H_{v}(u,v),\ -\Delta v=H_{u}(u,v) \ \ \text{ in } \Omega, \qquad u,v=0 \text{ on } \partial \Omega$$ where $H$ is a power-type nonlinearity, for instance $H(u,v)= |u|^p/p+|v|^q/q$, having subcritical growth, and $\Omega$ is a bounded domain of $\mathbb{R}^N$, $N\geq 1$. The aim of this paper is to give an overview of the several variational frameworks that can be used to treat such a system. Within each approach, we address existence of solutions, and in particular of ground state solutions. Some of the available frameworks are more adequate to derive certain qualitative properties; we illustrate this in the second half of this survey, where we also review some of the most recent literature dealing mainly with symmetry, concentration, and multiplicity results. This paper contains some original results as well as new proofs and approaches to known facts.Comment: 78 pages, 7 figures. This corresponds to the second version of this paper. With respect to the original version, this one contains additional references, and some misprints were correcte

Estirpes de Escherichia coli patogénicas e resistentes a antibióticos em efluentes de águas residuais tratadas com radiação UV

Antibiotic resistance jeopardizes the treatment of bacterial infections worldwide, with clinical and environmental compartments being recognized in its pandemic dissemination. Wastewater Treatment Plants (WWTPs) are notorious sources of antibiotic resistance into the aquatic systems and are thus considered a key node for containing the antibiotic resistance dissemination across the humanenvironmental microbiota axis. In this extent, disinfection of effluents before their discharge (e.g. by UV-C irradiation) is a promising strategy. However, some clinically relevant bacteria have been shown to survive such disinfection steps, though a knowledge gap exists in what regards their phenotypic and genotypic features. In this study we characterized a collection of clinically relevant extended-spectrum beta-lactamase-producing Escherichia coli isolated from an WWTP’s UV-C-irradiated effluent, aiming to identify putative human health risks associated with such effluents. Twenty-five strains of antibiotic-resistant, CTX-M-producing E. coli were genotyped (rep-PCR, Pulsed-Field Gel Electrophoresis, Multilocus Sequence Typing and Clermont phylogrouping), antibiotic-resistant genes (ARGs) and virulence genes (VGs) were PCR-detected, plasmids were analysed by enzymatic restriction and conjugal transfer was evaluated by mating assays. Biofilm, siderophore and haemolysin production, cytotoxicity and invasion into Vero cells and infection of Galleria mellonella larvae were phenotypically assessed. Illumina whole-genome sequencing and evaluation of persistence in freshwater microcosms was performed for 6 selected strains. Analysis of rep-PCR profiles separated strains into 2 major groups, including strains affiliated either with phylogroup B2-sgI (n=7 isolates) or with phylogroups A (n=16) and C (n=2); and further separated into 8 known STs, namely B2:ST131 (n=7), A:ST58 (n=1), A:ST155 (n=4), C:ST410 (n=2), A:ST453 (n=2), A:ST617 (n=2), A:ST744 (n=1) and A:ST1284 (n=3). Of 18 PCR-screened ARGs, 9 were detected (i.e. sul1, sul2, sul3, tet(A), tet(B), blaOXA-1-like, aacA4, aacA4-cr and qnrS1). No VGs were identified by PCR. Plasmid restriction indicated high diversity of plasmid profiles among strains and mating assays yielded cefotaxime-resistant transconjugants for 8 strains, two of which displaying a multi-drug resistant (MDR) phenotype. All strains were classified as cytotoxic (9 significantly more cytotoxic than the positive control), 10 of 21 strains were invasive (particularly B2:ST131 strains) and 10 selected isolates were pathogenic to larvae. Twenty-four and 7 of the 25 strains produced siderophores and haemolysins, respectively. Approximately 65% of the tested strains formed biofilms, 11 in two distinct experimental conditions. Genome analysis identified additional ARGs (e.g. catB3, strA, strB) and several VGs encoding toxins, siderophores, and colonizing, adhesion and invasion factors. Four of 6 strains were still detected by cultivation and/or qPCR after 28 days of incubation in freshwater microcosms, and resistance phenotypes remained unaltered. In this study, we confirmed WWTP’s UV-C-treated outflow as an input source of MDR and/or virulent E. coli strains, some probably capable of persisting in freshwater, and carrying conjugative antibiotic resistance plasmids. Hence, UVdisinfected wastewater may still represent a risk for human health and antibiotic stewardship, which implies a lack of efficiency of this treatment to remove pathogens from wastewater, compromising water reuse. More detailed evaluation of strains isolated from other wastewater effluents is urgent, in order to design new treatments or establish synergistic combinations that can mitigate the release of such bacteria into the environment.A resistência a antibióticos compromete o tratamento de infecções bacterianas a nível mundial, sendo reconhecido o papel dos reservatórios clínicos e ambientais na sua disseminação. As Estações de Tratamentos de Águas Residuais (ETAR) são fontes de contaminação dos sistemas aquáticos com bactérias resistentes a antibióticos e genes de resistência. Por esta razão são consideradas nodos importantes onde pode ser contida a transferência de resistência no eixo microbiota humano-ambiental. A desinfecção dos efluentes tratados (e.g. por irradiação com UV-C) é uma estratégia promissora. No entanto, algumas bactérias de relevância clínica sobrevivem à desinfeção, desconhecendo-se as suas características fenotípicas e genotípicas. Neste estudo, caracterizámos estirpes de Escherichia coli produtoras de betalactamases de espectro alargado isoladas de um efluente tratado com radiação UV-C, com o objetivo de identificar potenciais riscos para a saúde humana associados a estes efluentes. Vinte e cinco estirpes de E. coli resistentes a antibióticos e produtoras de CTXM foram submetidas a genotipagem por rep-PCR, eletroforese em campo pulsado, sequenciação de múltiplos loci e determinação de filogrupos. Genes de resistência a antibióticos (GRAs) e genes de virulência (GV) foram detectados por PCR. Os plasmídeos foram analizados por restrição enzimática e a sua transferência avaliada por ensaios de conjugação. A produção de biofilmes, sideróforos e hemolisinas foi determinada fenotipicamente. Foi também avaliada a citoxicidade e invasão celular, usando células Vero, e a infecção de larvas de Galleria mellonella. Os genomas de 6 estirpes foram sequenciados e a sua persistência em água doce foi avaliada em microcosmos. A análise dos perfis de rep-PCR separou as estirpes em 2 grupos: 1) estirpes do filogrupo B2-sgI (n=7 isolados) e 2) estirpes dos filogrupos A (n=16) e C (n=2). As estirpes foram afiliadas a 8 clones conhecidos: B2:ST131 (n=7), A:ST58 (n=1), A:ST155 (n=4), C:ST410 (n=2), A:ST453 (n=2), A:ST617 (n=2), A:ST744 (n=1) e A:ST1284 (n=3). Dos 18 GRAs investigados por PCR, 9 foram detectados (i.e. sul1, sul2, sul3, tet(A), tet(B), blaOXA-1-like, aacA4, aacA4-cr and qnrS1). Nenhum GV foi identificado por PCR. Uma elevada diversidade de plasmídeos foi observada e foram obtidos transconjugantes resistentes à cefotaxima para 8 estirpes, em dois dos casos manifestando um fenótipo de multirresistência. Todas as estirpes foram classificadas como citotóxicas (9 significativamente mais citotóxicas que o controlo positivo), 10 em 21 estirpes eram invasivas (particularmente estirpes do grupo B2:ST131) e 10 estirpes seleccionadas eram patogénicas para larvas. Vinte e quatro e 7 das 25 estirpes produziram sideróforos e hemolisinas, respectivamente. Aproximadamente 65% das estirpes testadas formavam biofilmes, 11 das quais em duas condições experimentais. A análise dos genomas identificou GRAs adicionais (e.g. catB3, strA, strB) e vários GV codificantes de toxinas, sideróforos e factores de colonização, adesão e invasão. Quatro das 6 estirpes foram detectadas por cultivo e/ou qPCR após 28 dias de incubação em microcosmos, sendo que os seus fenótipos de resistência permaneceram inalterados. Neste estudo verificou-se que o efluente tratado com radiação UV-C é uma fonte de estirpes de E. coli multirresistentes e/ou virulentas, algumas das quais poderão persistir no sistema aquático recetor. Como tal, a água residual desinfetada com radiação UV pode ainda constituir um perigo para a saúde pública e para a eficácia geral dos antibióticos, comprometendo a sua reutilização. Uma avaliação mais detalhada de estirpes isoladas de outros efluentes de ETARs é urgente para que possamos desenvolver novos tratamentos, ou combinações sinérgicas destes, capazes de reduzir a libertação destas bactérias para o ambiente.Mestrado em Microbiologi

Gas and solid behaviours during defluidisation of Geldart-A particles

Bed collapsing experiments were carried out in a cold-air transparent column 192 mm in diameter and 2 m high. Typical Fluid Catalytic Cracking (FCC) catalyst with a mean particle size of 76 μm and a density of 1400 kg/m3 was used. Both single and double-drainage protocols were tested. The local pressure drop and bed surface collapse height were acquired throughout the bed settling.Typical results were found regarding dense phase voidage of a fluidised bed and the bed surface collapse velocity. In addition, bubble fraction was calculated based on the collapse curve.Experimental results showed that windbox effect is significantly reduced compared to previous works since the volume of air within the windbox was reduced. The comparison of single/double-drainage protocols revealed a new period in the defluidisation of Geldart-A particles concerning gas compressibility. Through the temporal analysis of local pressure drop, the progress of the solid sedimentation front from bottom to top was determined, analysed and modelled

Analysis of syntaxin-1 chaperones during synaptic activity

Tese de mestrado em Bioquímica, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2011Neuronal communication is based on synaptic vesicle exocytosis, which is strongly regulated. The release of neurotransmitters from presynaptic nerve terminals requires cycles of protein-protein interactions. SNARE and SM proteins are universally involved in all intracellular membrane fusion reactions, and reside either on the target membrane (syntaxin-1 and synaptosome-associated protein of 25kDa (SNAP-25) or on the synaptic vesicle (synaptobrevin-2). Recent studies have identified chaperones for two SNARE proteins: synaptobrevin-2 and SNAP-25 . Since these SNARE chaperones seem essential for the long-term functioning of synapses, the question arises which molecule(s) may chaperone syntaxin-1. Previous studies have suggested that Munc-18 and SNAP-25 may chaperone syntaxin-1. Furthermore, it has been shown that chemical modification of syntaxin-1 or mutation on cysteine residue 145 increases its stability. To investigate a possible chaperone function of Munc-18 and SNAP-25 for syntaxin-1, I aimed to clarify whether this chemical modification inhibits syntaxin-1 degradation, whether the C145S mutation reproduces this modification, and whether this cysteine is normally involved in ubiquitination and degradation of syntaxin-1. To approach these aims, HEK-293T cells and neuronal cultures from wild-type mice were used in combination with overexpression of syntaxin-1 full-length, several truncations and its mutant C145S. Chemical agents were used to monitor syntaxin-1 levels. These experiments were analyzed by immunoprecipitation, immunoblotting or immunocytochemistry. Results suggest that munc-18 chaperones syntaxin-1, based on the following observations: 1) it increases syntaxin-1 levels and inhibits syntaxin-1 degradation in cotransfected HEK cells; 2) C145S mutation significantly stabilizes syntaxin-1 levels and results in less degradation products. C145S also dramatically reduces ubiquitination of syntaxin-1; 3) syntaxin-1 may be degraded via the lysosome. Lysosomal inhibitors revealed a trend towards stabilization of syntaxin-1 whereas proteasomal inhibitors showed no change. Yet, further experiments are needed to understand the precise role of C145S in the degradation mechanism of syntaxin-1

Violence in literature : the romance of violence in Latin America

The purpose of this essay is to analyse what could be seen as a transformation of a genre of fiction, the novel of violence. In sociological tradition, various authors have chosen the detective novel as a research object to explain modernity. This sociological tradition in studies of detective fiction allows us to suggest the emergence of another form of romance, the novel of violence, in the last thirty years. In México, the latest works of Carlos Fuentes (México, 1928-2012) belong to this genre of novels. Also, Elmer Mendoza (México, 1949-) who write about the detective and the organised crime. In the novels of violence, crime and solution are secondary, because violence is seen as a structuring element of social reality. New forms of murders arise: violent crimes, international drug trafficking, sexual abuse and violence, rape, corruption, and torture. These forms appear as an aesthetic of “brutalism” and “cruelty”. The world of the novel of violence is a world without law, defined by the ineffectiveness or simply the absence of the police or the judiciary. There is a lack of a legitimate authority, formal or informal, signifying the crisis of the judicial system. But, also, this literature appears to have worldwide lectors in late modernity

Poseidon Linux 3.x - The scientific GNU/Linux option

This software review is about the newest version of Poseidon Linux (3.x). The current Poseidon Linux is a remastering from Ubuntu LTS family (Long Term Support), with extra specific software applicable to many areas of scientific research and education. It contains specialist software for GIS/Mapping, bathymetry, numerical modeling, 2D/3D/4D visualization, bioinformatics, chemistry, statistics, as well as tools for creating simple and complex graphics and programming languages. It also includes basic packages as would be expected on a normal desktop, such as a complete office suite, internet browser, e-mail client, instant messaging, chat, multimedia and many other tools. Poseidon Linux can run in two modes, as a live-DVD or installed on the hard disk. There are versions for 32 and 64 bit computers, and support for Brazilian Portuguese, English, Spanish, French, Greek, Italian and German languages. Resumo. Poseidon Linux 3.x – A opção científica GNU/Linux. Esta resenha trata da nova versão do software Poseidon Linux (3.x). A versão atual é uma remasterização a partir do sistema operacional Ubuntu, família LTS (Suporte de Longo Prazo), com pacotes extras para várias áreas da ciência e educação. Contém programas específicos para SIG/mapeamento, batimetria, modelagem numérica, visualização 2D/3D/4D, bioinformática, química, estatística, bem como ferramentas para elaboração de gráficos simples e complexos e linguagem de programação. Inclui também os programas necessários encontrados num sistema operacional desktop, tais como suporte completo para escritório, navegador de internet, programas para envio e recebimento de mensagens instantâneas, multimídia e várias outras ferramentas. O Poseidon Linux pode ser utilizado de duas formas: diretamente do DVD, sem instalá-lo, ou instalando-o no disco rígido do computador. É apresentado nas versões 32 e 64 bits e pode ser totalmente configurado em Português do Brasil, Inglês, Espanhol, Francês, Grego, Italiano e Alemão

Descobrimentos e navegações no Archivo Historico Portuguez

Tese de mestrado, Geografia, Universidade de Lisboa, Faculdade de Letras, 2012A presente dissertação propõe-se evidenciar os “Descobrimentos e Navegações no Archivo Historico Portuguez”, situando este periódico na produção historiográfica do tempo e destacando Anselmo Braamcamp Freire, enquanto fundador desta revista de história, procurando entrever o homem e o historiador. Compreensão que passa pela análise dos seus colaboradores e pelas tendências historiográficas da época; os eruditos e as revistas, ainda não especializadas mas generalistas em que publicavam os seus estudos históricos; e, ainda, a historiografia dos Descobrimentos tendo em conta os homens e as embarcações que os materializaramABSTRACT: This dissertation analyses the “Discoveries and Navigations in the Archivo Historico Portuguez” by placing this periodic in the time’s historiographical production and Anselmo Braamcamp Freire, as a founder of this history magazine, studying the man and the historian. In order to understand the periodical collaborators and the historiographical tendencies of that time; as well as the scholars and the magazines not yet specialized but generalist in which they publicized their historical studies; and, furthermore, the history of the Discoveries focus on the men and the vessels