5,786 research outputs found
Chloride penetration into carbonated concrete
To ensure the durability of concrete structures it is necessary to understand its behaviour in the presence of aggressive agents. Carbonation and chloride action are the two leading causes of degradation in reinforced concrete structures. Â Despite the combined action of these two mechanisms being a reality, there is little research on the effect of CO2 presence on the chloride behaviour in concrete.
This work studies the total chlorides ingress into carbonated concrete. For this, samples with CEM I 42.5R were cast with 0.6 of water/binder ratio. After 90 days of the curing period, half of the samples were subjected to accelerated carbonation (20ºC, 55%Relative Humidity and 4%CO2) for 1 month. The other half was protected with a plastic film during the same period. Chloride immersion test, based on LNEC E390 (Portuguese specification), were performed with samples subjected to both experimental conditions. Afterwards, the depth of chlorides and CO2 penetration was evaluated.
The results show that, for these conditions, the CO2 presence has a direct influence on chloride behaviour. The non-carbonated samples showed a profile with a higher amount of chloride than carbonated ones.Authors thank the foundation for science and technology (FCT) for supporting this research
A novel multivariate STeady-state index during general ANesthesia (STAN)
The assessment of the adequacy of general anesthesia for surgery, namely the nociception/anti-nociception balance, has received wide attention from the scientific community. Monitoring systems based on the frontal EEG/EMG, or autonomic state reactions (e.g. heart rate and blood pressure) have been developed aiming to objectively assess this balance. In this study a new multivariate indicator of patients' steady-state during anesthesia (STAN) is proposed, based on wavelet analysis of signals linked to noxious activation. A clinical protocol was designed to analyze precise noxious stimuli (laryngoscopy/intubation, tetanic, and incision), under three different analgesic doses; patients were randomized to receive either remifentanil 2.0, 3.0 or 4.0 ng/ml. ECG, PPG, BP, BIS, EMG and [Formula: see text] were continuously recorded. ECG, PPG and BP were processed to extract beat-to-beat information, and [Formula: see text] curve used to estimate the respiration rate. A combined steady-state index based on wavelet analysis of these variables, was applied and compared between the three study groups and stimuli (Wilcoxon signed ranks, Kruskal-Wallis and Mann-Whitney tests). Following institutional approval and signing the informed consent thirty four patients were enrolled in this study (3 excluded due to signal loss during data collection). The BIS index of the EEG, frontal EMG, heart rate, BP, and PPG wave amplitude changed in response to different noxious stimuli. Laryngoscopy/intubation was the stimulus with the more pronounced response [Formula: see text]. These variables were used in the construction of the combined index STAN; STAN responded adequately to noxious stimuli, with a more pronounced response to laryngoscopy/intubation (18.5-43.1 %, [Formula: see text]), and the attenuation provided by the analgesic, detecting steady-state periods in the different physiological signals analyzed (approximately 50 % of the total study time). A new multivariate approach for the assessment of the patient steady-state during general anesthesia was developed. The proposed wavelet based multivariate index responds adequately to different noxious stimuli, and attenuation provided by the analgesic in a dose-dependent manner for each stimulus analyzed in this study.The first author was supported by a scholarship from the Portuguese Foundation for Science and Technology (FCT SFRH/BD/35879/2007). The authors would also like to acknowledge the support of UISPA—System Integration and Process Automation Unit—Part of the LAETA (Associated Laboratory of Energy,
Transports and Aeronautics) a I&D Unit of the Foundation for Science and Technology (FCT), Portugal. FCT support under project PEst-OE/EME/LA0022/2013.info:eu-repo/semantics/publishedVersio
The Brazilian health system at crossroads: progress, crisis and resilience
The Unified Health System (Sistema Único de Saúde (SUS)) has enabled substantial progress towards Universal Health Coverage (UHC) in Brazil. However, structural weakness, economic and political crises and austerity policies that have capped public expenditure growth are threatening its sustainability and outcomes. This paper analyses the Brazilian health system progress since 2000 and the current and potential effects of the coalescing economic and political crises and the subsequent austerity policies. We use literature review, policy analysis and secondary data from governmental sources in 2000–2017 to examine changes in political and economic context, health financing, health resources and healthcare service coverage in SUS. We find that, despite a favourable context, which enabled expansion of UHC from 2003 to 2014, structural problems persist in SUS, including gaps in organisation and governance, low public funding and suboptimal resource allocation. Consequently, large regional disparities exist in access to healthcare services and health outcomes, with poorer regions and lower socioeconomic population groups disadvantaged the most. These structural problems and disparities will likely worsen with the austerity measures introduced by the current government, and risk reversing the achievements of SUS in improving population health outcomes. The speed at which adverse effects of the current and political crises are manifested in the Brazilian health system underscores the importance of enhancing health system resilience to counteract external shocks (such as economic and political crises) and internal shocks (such as sector-specific austerity policies and rapid ageing leading to rise in disease burden) to protect hard-achieved progress towards UHC
Fluxo de gases (CH4, N2O e CO2) em área de cana-de-açúcar sem queima irrigada com efluente de esgoto tratado.
O reuso agrícola de efluentes de esgoto tratado (EET) é uma prática de interesse ambiental e econômico, contudo, seu impacto em solos brasileiros ainda é pouco conhecido. Dentre as culturas com características favoráveis para o reuso agrícola, a cana-de-açúcar se destaca, por possuir elevado potencial para o cultivo irrigado e pela crescente expansão, incentivada pela produção de biocombustíveis. Com o objetivo de avaliar o efeito da irrigação da cana-de açúcar (Saccharum officinarum) com efluente de esgoto tratado sobre a emissão de gases (CH4, N2O e CO2) relacionados com o efeito estufa, foi conduzido um experimento em Piracicaba, SP, em área próxima a uma à estação de tratamento de esgoto (ETE). A avaliação das emissões foi conduzida 4 meses após a rebrota, referente à segunda soca da cana-de-açúcar. Não foram observados efeitos do manejo da irrigação com EET nos fluxos de CH4 e N2O a partir do solo. A irrigação com EET promoveu um aumento linear nas emissões de CO2 nas lâminas com 100% da Evapotranspiração da cultura (Etc) e de 200% da Etc, elevaram as emissões de CO2 em 33 e 146% pelo solo cultivado com cana de açúcar
Semiclassical theory of potential scattering for massless Dirac fermions
In this paper we study scattering of two-dimensional massless Dirac fermions
by a potential that depends on a single Cartesian variable. Depending on the
energy of the incoming particle and its angle of incidence, there are three
different regimes of scattering. To find the reflection and transmission
coefficients in these regimes, we apply the Wentzel-Kramers-Brillouin (WKB),
also called semiclassical, approximation. We use the method of comparison
equations to extend our prediction to nearly normal incidence, where the
conventional WKB method should be modified due to the degeneracy of turning
points. We compare our results to numerical calculations and find good
agreement.Comment: Minor revision; several references have been adde
STRATHERN, Marilyn. O efeito etnográfico e outros ensaios. Coordenação editorial: Florencia Ferrari. Tradução: Iracema Dullei, Jamille Pinheiro e Luísa Valentini. São Paulo: Cosac Naify, 2014. 576 p.
Identification of secreted virulence factors of Chromobacterium violaceum.
Made available in DSpace on 2018-06-26T01:01:37Z (GMT). No. of bitstreams: 1
art10.1007s1227501432025.pdf: 175682 bytes, checksum: 1d1e24a76ce448f7b393774e818ea4f8 (MD5)
Previous issue date: 2015-01-16bitstream/item/115792/1/art-10.1007-s12275-014-3202-5.pd
- …