2,648 research outputs found
The Nlrc4 Inflammasome Contributes to Restriction of Pulmonary Infection by Flagellated Legionella spp. that Trigger Pyroptosis
The Nlrc4 inflammasome is triggered in response to contamination of the host cell cytoplasm with bacterial flagellin, which induces pyroptosis, a form of cell death that accounts for restriction of bacterial infections. Although induction of pyroptosis has been extensively investigated in response to Salmonella typhimurium and Legionella pneumophila, little is known regarding the role of the inflammasome for restriction of non-pneumophila Legionella species. Here, we used five species of the Legionella genus to investigate the importance of the inflammasome for restriction of bacterial infection in vivo. By infecting mice deficient for inflammasome components, we demonstrated that caspase-1 and Nlrc4, but not Asc, contribute to restriction of pulmonary infection with L. micdadei, L. bozemanii, L. gratiana, and L. rubrilucens. L. longbeachae, a non-flagellated bacterium that fails to trigger pyroptosis, was not restricted by the inflammasome and induced death in the infected mice. In contrast to L. longbeachae, flagellin mutants of L. pneumophila did not induce mice death; therefore, besides bypassing the Nlrc4 inflammasome, L. longbeachae may employ additional virulence strategies to replicate in mammalian hosts. Collectively, our data indicate that the Nlrc4 inflammasome plays an important role in host protection against opportunistic pathogenic bacteria that express flagellin
Compression and bending behavior of steel fiber reinforced self-compacting concrete
A method to design cost competitive steel fiber reinforced self-compacting concrete (SFRSCC) for precasting industrial applications is described in this paper. Since demolding the elements as soon as possible is an important requirement in this industry, the influence of the age on the resistance and toughness of the designed SFRSCC was assessed carrying out an experimental program. Based on the force-deflection relationship obtained in the three point bending notched beam tests performed according to the RILEM TC 162-TDF recommendations, the stress-crack opening relationship of the SFRSCC was determined. The influence of the SFRSCC age on the fracture parameters of this material was analyzed.Inserido no programa de pesquisa suportado pelo FEDER e o Ministério da Ciência e Tecnologia (MCT) e promovido pelo Agencia de Inovação (ADI)
Supermassive Black Holes: Connecting the Growth to the Cosmic Star Formation Rate
In this Letter, we present a model connecting the cosmic star formation rate
(CSFR) to the growth of supermassive black holes. Considering that the
evolution of the massive black hole is dominated by accretion (Soltan's
argument) and that the accretion process can be described by a probabilistic
function directly regulated by the CSFR, we obtain the evolution of the black
hole mass density. Then using the quasar luminosity function, we determine both
the functional form of the radiative efficiency and the evolution of the quasar
duty-cycle as functions of the redshift. We analyze four different CSFRs
showing that the quasar duty-cycle, , peaks at and so
within the window associated with the reionization of the Universe. In
particular, depending on the CSFR. The mean
radiative efficiency, , peaks at with
depending on the specific CSFR used. Our
results also show that is not necessary a supercritical Eddington accretComment: accepted for publication in MNRAS Letters (5 pages, 6 figures), Some
typos fixed; MNRAS Letters 17 Aug 201
On the strength of acids and bases: some considerations
This article intends to answer the question: what is the best way to evaluate the strength of acids and bases? The meaning of the word strength, the main acid-base theories (ionotropic and electron pair), the neutralization reactions and the thermodynamical formalism are considered. Some cases are presented and discussed. In conclusion, evaluating acid-base strength is dependent on the theory (formalism) as well as on the system and measuring techniques.1591159
Sobre a força de ácidos e bases: algumas considerações
This article intends to answer the question: "what is the best way to evaluate the strength of acids and bases?" The meaning of the word strength, the main acid-base theories (ionotropic and electron pair), the neutralization reactions and the thermodynamical formalism are considered. Some cases are presented and discussed. In conclusion, evaluating acid-base strength is dependent on the theory (formalism) as well as on the system and measuring techniques
Graft incompatibility in Prunus
A incompatibilidade de enxertia é um problema
que, além de prejuÃzo econômico aos produtores, causa atraso
no lançamento de novas cultivares-copa e portaenxertos,
devido ao longo perÃodo de tempo necessário para os testes de
compatibilidade. O objetivo desta revisão é fazer um apanhado
das principais e mais relevantes pesquisas realizadas envolvendo
o tema incompatibilidade de enxertia em espécies frutÃferas,
especialmente as do gênero Prunus. Incompatibilidade é um
fenômeno extremamente complexo, que envolve interações
anatômicas, fi siológicas, bioquÃmicas e moleculares entre a
cultivar-copa e o portaenxerto. Sendo, por essa razão, um problema
de difÃcil estudo. Porém, acredita-se que através de uma análise
conjunta dos diversos mecanismos de incompatibilidade, se pode
avançar mais rapidamente no entendimento deste fenômeno.The graft incompatibility is a problem that causes
economic loss to producers and delay in the launch of new cultivars
and rootstock because of the long time required for compatibility
testing. The aim of this review is to show of the most important
and relevant research conducted over the years involving the graft
incompatibility in fruit species, specially the genus Prunus. The
graft incompatibility is an extremely complex phenomenon that
involves anatomical, physiological, biochemical and molecular
interactions between scion and rootstock. Being for this reason a
diffi cult problem to analyze. However, it is believed that through
a joint analysis of graft incompatibility the understanding of the
mechanisms may advance more quickly and so allow the solution
for the phenomenon.Publishe
Stellar-to-halo mass relation of cluster galaxies
In the hierarchical formation model, galaxy clusters grow by accretion of
smaller groups or isolated galaxies. During the infall into the centre of a
cluster, the properties of accreted galaxies change. In particular, both
observations and numerical simulations suggest that its dark matter halo is
stripped by the tidal forces of the host.
We use galaxy-galaxy weak lensing to measure the average mass of dark matter
haloes of satellite galaxies as a function of projected distance to the centre
of the host, for different stellar mass bins. Assuming that the stellar
component of the galaxy is less disrupted by tidal stripping, stellar mass can
be used as a proxy of the infall mass. We study the stellar to halo mass
relation of satellites as a function of the cluster-centric distance to measure
tidal stripping.
We use the shear catalogues of the DES science verification archive, the
CFHTLenS and the CFHT Stripe 82 (CS82) surveys, and we select satellites from
the redMaPPer catalogue of clusters. For galaxies located in the outskirts of
clusters, we find a stellar to halo mass relation in good agreement with the
theoretical expectations from \citet{moster2013} for central galaxies. In the
centre of the cluster, we find that this relation is shifted to smaller halo
mass for a given stellar mass. We interpret this finding as further evidence
for tidal stripping of dark matter haloes in high density environments.Comment: 15 pages, 14 figure
Evaluation of Road Signs conformity for improving road safety in urban Areas: a Case Study in Guimarães, Portugal
A segurança rodoviária depende da existência de uma rede de sinalética apropriada e de uma correta manutenção dos sinais ao longo do tempo. Os sinais verticais de trânsito, para serem efetivamente funcionais, devem permanecer adequadamente visÃveis e percetÃveis. Neste artigo apresenta-se uma metodologia para avaliar o nÃvel de conformidade dos sinais, procurando identificar eventuais deficiências funcionais. A metodologia baseia-se numa análise multicritério, onde são considerados dois critérios e oito subcritérios relacionados com as caracterÃsticas fÃsicas e operacionais dos sinais. A visibilidade dos sinais foi avaliada através de uma análise em SIG, considerando as distâncias de travagem e de paragem. O nÃvel de intervenção obtido é constituÃdo por quatro nÃveis, em função da necessidade e da urgência em recuperar a função dos sinais. A metodologia foi aplicada na cidade de Guimarães, Portugal. Os resultados comprovam a funcionalidade da metodologia e revelam que mais de metade dos sinais analisados não estão totalmente em conformidade com as normas, muito por culpa da estrutura urbana compacta e da presença de vegetação nas ruas. Uma vez que, para vários sinais, as distâncias de travagem e de paragem não são adequadas, pode-se concluir que os utilizadores destas ruas estão expostos a riscos que ameaçam a sua segurança.Road safety depends on the existence of an adequate network of signs and an effective management for proper conservation. Vertical traffic signs will only be effectively functional if they still provide adequate visibility
and legibility. This paper presents a methodology to evaluate the level of conformity of traffic signs, in order
to identify where to improve their functionality. The methodology is based on a multicriteria analysis, using
two criteria and eight subcriteria that are related with signs physical and operational attributes. Their visibility
was evaluated through a spatial analysis in a geographical information system, taking into account the
braking and stopping distances. The intervention level is defined by four levels related with the necessity and
urgency in restoring signs functionality. This methodology was applied in the city of Guimarães, Portugal. The
results showed the usefulness of the methodology and revealed that more than half of the analyzed signs not
fully complied with the norms, mainly due to the compactness of the urban structure e the presence of vegetation
in streets. Since the braking and stopping distances of many signs are not adequate, it can be concluded
that road users are exposed to risks and their safety can be threated.info:eu-repo/semantics/publishedVersio
Avaliação da visibilidade de sinais de trânsito com base numa análise multicritério implementada num SIG. Uma aplicação no centro de Guimarães, Portugal
Publicado em "Anais do 7º Congresso Luso-Brasileiro para o Planejamento Urbano, Regional, Integrado e Sustentável"A visibilidade dos sinais de trânsito é fundamental para regular o tráfego rodoviário, auxiliar os condutores e garantir a segurança dos utilizadores das vias. Neste artigo apresenta-se uma metodologia para avaliar a visibilidade dos sinais verticais de trânsito. Com base numa análise multicritério, atribuiram-se pesos a três parâmetros que condicionam a visibilidade dos sinais: a dimensão do sinal, a dimensão do poste e a visibilidade do sinal. A análise da visibilidade foi realizada através do geoprocessamento num SIG a partir da rasterização do terreno. Com a aplicação da análise multicritério obteve-se uma escala de prioridades de intervenção associada à visibilidade dos sinais. Esta metodologia foi aplicada a um conjunto de sinais na cidade de Guimarães, Portugal. Os resultados comprovam a funcionalidade da metodologia e revelam que os sinais na cidade de Guimarães têm problemas de visibilidade resultantes da estrutura urbana compacta e da presença de vegetação nas ruas
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