Produtos de contraste iodados

A aplicação na medicina dos produtos de contraste iodados é uma realidade com a qual a generalidade dos médicos deve estar familiarizada. Através de uma abordagem sucinta, o presente artigo pretende simplificar a compreensão dos diversos tipos de contraste, suas propriedades, utilidade clínica e reacções adversas

Bridge-specific fragility analysis: when is it really necessary?

In seismic assessment of bridges the research focus has recently shifted on the derivation of bridge-specific fragility curves that account for the effect of different geometry, structural system, component and soil properties, on the seismic behaviour. In this context, a new, component-based methodology for the derivation of bridge-specific fragility curves has been recently proposed by the authors, with a view to overcoming the inherent difficulties in assessing all bridges of a road network and the drawbacks of existing methodologies, which use the same group of fragility curves for bridges within the same typological class. The main objective of this paper is to critically assess the necessity of bridge-specific fragility analysis, starting from the effect of structure-specific parameters on component capacity (limit state thresholds), seismic demand, and fragility curves. The aforementioned methodology is used to derive fragility curves for all bridges within an actual road network, with a view to investigating the consistency of adopting generic fragility curves for bridges that fall within the same class and quantifying the degree of over- or under-estimation of the probability of damage when generic bridge classes are considered. Moreover, fragility curves for all representative bridges of the analysed concrete bridge classes are presented to illustrate the differentiation in bridge fragility for varying structural systems, bridge geometry, total bridge length and maximum pier height. Based on the above, the relevance of bridge-specific fragility analysis is assessed, and pertinent conclusions are drawn

Analysis of ground reaction force and electromyographic activity of the gastrocnemius muscle during double support

O documento em anexo encontra-se na versão post-print (versão corrigida pelo editor).Purpose: Mechanisms associated with energy expenditure during gait have been extensively researched and studied. According to the double-inverted pendulum model energy expenditure is higher during double support, as lower limbs need to work to redirect the centre of mass velocity. This study looks into how the ground reaction force (GRF) of one limb affects the muscle activity required by the medial gastrocnemius (MG) of the contralateral limb during step-to-step transition. Methods: Thirty-five subjects were monitored as to the MG electromyographic activity (EMGa) of one limb and the GRF of the contralateral limb during double support. Results: After determination of the Pearson correlation coefficient (r), a moderate correlation was observed between the MG EMGa of the dominant leg and the vertical (Fz) and anteroposterior (Fy) components of GRF of the non-dominant leg (r=0.797, p<0.0001; r=-0.807, p<0.0001) and a weak and moderate correlation was observed between the MG EMGa of the non-dominant leg and the Fz and Fy of the dominant leg, respectively (r=0.442, p=0.018; r=-0.684 p<0.0001). Conclusions: The results obtained suggest that during double support, GRF is associated with the EMGa of the contralateral MG and that there is an increased dependence between the GRF of the non-dominant leg and the EMGa of the dominant MG

Are ant assemblages of Brazilian veredas characterised by location or habitat type?

Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species.Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat

Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector

The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV

Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector

This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}$and correspond to an integrated luminosity of$4.6\;{\rm f}{{{\rm b}}^{-1}}$. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum${{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}$and pseudorapidity$|\eta |\lt 1.9$, is measured to be${{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured

Enhancing Egress Drills: Preparation and Assessment of Evacuee Performance

This article explores how egress drills-specifically those related to fire incidents-are currently used, their impact on safety levels, and the insights gained from them. It is suggested that neither the merits of egress drills are well understood, nor the impact on egress performance well characterized. In addition, the manner in which they are conducted varies both between and within regulatory jurisdictions. By investigating their strengths and limitations, this article suggests opportunities for their enhancement possibly through the use of other egress models to support and expand upon the benefits provided. It is by no means suggested that drills are not important to evacuation safety-only that their inconsistent use and the interpretation of the results produced may mean we (as researchers, practitioners, regulators, and stakeholders) are not getting the maximum benefit out of this important tool