1,221 research outputs found
Vibration analysis and modal identification of a circular cable-stayed footbridge
Vibration measurements and modal identification were performed on a footbridge as part of the
commissioning tests. The deck presents a circular configuration, in plant, and is suspended from
eight cables connecting it to the extremity of a steel mast anchored to a concrete bulk situated on
the riverside. The dynamic measurements were aimed to control the force installed in the cables
during the tension operation and to characterize the dynamic parameters through output-only modal
identification techniques in order to calibrate a Finite Element model. At last, groups of pedestrians
crossed the bridge at various speeds allowing conclusions about the vibration amplitudes that can
be expected during real use of the bridge
Atrioventricular block related to liposomal amphotericin B
Atrioventricular block can occur in normal children, young adults or athletes. It is also associated with underlying heart disease or occurs as a drug adverse effect. Amphotericin B is used in the treatment of invasive fungal infections. Cardiac toxicity is a rare adverse reaction. We report the case of a 9-month girl, admitted in the paediatric intensive care unit with cytomegalovirus pneumonitis. During hospitalisation the patient developed a systemic fungic infection and was medicated with liposomal amphotericin B. On the third day of treatment she began repeated episodes of bradycardia with spontaneous reversion. The investigation revealed a second-degree atrioventricular block. We excluded the misplacement of the central catheter, myocarditis or structural cardiomyopathy and suspended amphotericin. After 8 days, the bradycardia episodes ceased what was consistent with the drug's half-life. Amphotericin cardiotoxic mechanism is still unclear. It may be related with alteration of myocardial membrane depolarisation.info:eu-repo/semantics/publishedVersio
Comportamento dinâmico de pontes pedonais de madeira
Na Parte 2 do Eurocódigo 5 é proposto, para tipologias correntes, um processo simplificado de verificação do estado-limite de vibração para pontes de madeira sujeitas à acção de grupos de peões, o qual utiliza estimativas do valor máximo da aceleração no tabuleiro.
Neste trabalho procede-se à comparação entre os valores determinados por esse método e os obtidos por análise dinâmica de modelos numéricos de Elementos Finitos, sob a acção de grupos de peões de dimensão e frequência de passada variáveis.
Descrevem-se ainda os modelos probabilÃsticos utilizados na geração do carregamento dinâmico correspondente a estes grupos
Selective pressure acting on influenza virus neuraminidase protein and relation with development of resistance to antiviral drugs
Neuraminidase (NA) protein of influenza viruses has the particularity of being under antibody and antiviral drug selective pressure, as it is one of the main surface antigens and the target of neuraminidase inhibitors(NAIs).
The aim of this study is to investigate the selective pressure(SP) acting on the NA of seasonal and pandemic influenza viruses. It comprises two objectives: (a)to evaluate the contribution of positive SP for the emergence of NAIs resistant viruses; and (b)to determine the impact of NAIs introduction into clinic and its wide use during pandemic on the SP acting on NA.
For the 1st objective it will be analysed the SP acting on the sites associated with NAIs resistance or reduction in susceptibility. The 2nd objective implies a differential evolutionary pressure analysis according to time, with 3 sub-datasets of NA sequences being considered: (1)before worldwide introduction of NAIs into clinic(1999); (2)before wide use of oseltamivir during A(H1N1)2009 pandemic(2009); and (3)from 2009 to date.
A large dataset of full-length NA coding sequences will be used for each (sub)type/variant, comprising sequences obtained at national level(since 2000/2001) and sequences available at GISAID and NCBI. A(H1N1)seasonal dataset was already created, including a total of 1523 sequences, from which 94 belong to 1st sub-dataset, 1094 to 2nd and 335 to 3rd. All SP analysis will be performed using the expertise acquired with this workshop.
This study may contribute for understanding the role of antiviral drug selective pressure in NAIs resistance, patterns of emergency of resistant viruses and NA evoluti
Evaluation and Characterization of Influenza Antiviral Drug Resistance in Portugal: Major Results and Achievements of a 5-Year Study
In 2007 started to be carried out for the first time in Portugal a study focused on influenza antiviral drug resistance. Three main objectives were established:(1)to determine the antiviral profile of influenza viruses to oseltamivir, zanamivir and amantadine;(2)to determine and monitor the baseline level of susceptibility along winter seasons and for each influenza sub(type);(3)to analyse and characterize the whole genome of viruses that showed phenotypic levels of inhibition to neuraminidase inhibitors(NAIs).
NAIs profile was determined phenotypically, using a fluorescence MUNUNA assay, and genotypically by NA and HA sequencing. A total of 340 seasonal viruses(117 A(H3N2),93 A(H1N1),130 B) were tested for oseltamivir and of 297(112 A(H3N2),68 A(H1N1),117 B) for zanamivir. Additionally, 142 A(H1N1)pdm09 viruses were evaluated for both NAIs. Whole genome sequencing was performed in 27 of the A(H1N1)pdm09 viruses. Amantadine profile was determined through M2 pyrosequencing or conventional sequencing in a total of 205 seasonal A viruses(138 A(H3N2),84 A(H1N1)) and of 117 A(H1N1)pdm09 viruses.
Main results are:
-Resistance to oseltamivir in 27 A(H1N1) seasonal viruses(29%,N=93) from 2007/2008 and 2008/2009 and in one A(H1N1)pdm09 virus(0.7%,N=142) from 2010/2011. These viruses exhibited a highly reduced level of inhibition to oseltamivir by phenotypic analysis (170-650 IC50 fold-change) and NA H275Y mutation;
-One suspected case of clinical resistance to oseltamivir with a mixed population of H275Y viruses(73,8%H275,26.2%Y275);
-No resistance to zanamivir;
-Dual reduced susceptibility to oseltamivir and zanamivir in one B virus(0,85%,N=117) and in two A(H1N1)pdm09 viruses(1,41%,N=142). These viruses exhibited a 2-4 IC50 fold-change level of inhibition to both NAIs. A mixed population of D197N viruses was found in the B virus(56%D197,44%N197) and the two A(H1N1)pdm09 viruses shared NA I223V and PB2 V480I mutations;
-Resistance to amantadine in 49 A(H3N2) viruses(35,5%,N=138) from 2005/2006 to 2008/2009(46 S31N,3 S31N+V27A), and in all A(H1N1)pdm09 viruses(S31N).
This 5-year study allowed to establish a technical platform for influenza antiviral drug resistance evaluation, to timely detect the emergence of resistant viruses, to acquire know-how on the natural variation of virus susceptibility, and to contribute for the management of cases suspected of clinical resistance. Additionally, it allowed the gathering of a large amount of data that will be used in more advanced studies, focused on evolutionary analysis and on detailed characterization of specific mutations
Thalamic deep brain stimulation may relieve breathlessness in COPD
The cerebral mechanisms of dyspnoea (breathlessness) are not well understood. Neuroimaging studies of experimentally induced dyspnoea in healthy individuals have identified several cortical areas that might form a neural network for perception of dyspnoea [1], much like those identified for pain perception [2]. However, functional imaging studies alone do not reveal neurophysiological pathways and may miss putative targets for dyspnoea relief. The objective of this study was to assess the effects of Deep Brain Stimulation (DBS) of four different brain nuclei on the sensation of dyspnoea in an individual with Chronic Obstructive Pulmonary Disease (COPD) using an established multidimensional dyspnoea tool [3]
Socio-emotional competences in Portuguese youngsters: Developing of assessment tools for parents
Social Competence (SC): ability to manage behavior, cognition and affection in order to achieve their social objectives (Waters & Sroufe, 1983). Is multifold and involve positive relationships with others; social cognition appropriate to age; deprivation of maladaptive behaviors and effective social skills (Candeias, 2001).
Emotional Intelligence (EI): is a cross-section of interrelated emotional and social competencies, skills and facilitators that determine how effectively we understand and express ourselves, understand others and relate with them, and cope with daily demands. (Bar-On, 2006)
Analysis of a model with a common source of CP violation
We work in a model where all CP violating phenomena have a common source. CP
is spontaneously broken at a large scale through the phase of a complex
singlet scalar. An additional singlet vector-like down-type quark
relates this high scale CP violation to low energy. We quantitatively analyze
this model in the quark sector. We obtain the numerical values of the
parameters of the Lagrangian in the quark sector for a specific ansatz of the
down-type quark mass matrix where the weak phase is generated
minimally. vertex will modify in presence of the extra vector-like
down-type quark. From the experimental lower bound of the partial decay width
we find out the lower bound of the additional down-type quark
mass. Tree level flavor changing neutral current appears in this model due to
the presence of the extra vector-like down-type quark. We give the range of
values of the mass splitting in system
using SM box, mediating tree level and mediating one loop diagrams
together for both . We find out the analytical expression for
in this model from standard box, and Higgs mediated penguin
diagrams for system, . From this we numerically
evaluate the decay width difference . We
also find out the numerical values of the CP asymmetry parameters and
for the decays and
respectively. We get the lower bound of the scale through the upper bound
of the strong CP phase.Comment: 20 pages, no figures New materials and references have been added.
Text has been modified. To be appear in J.Phys.
Radiocarbon and blue optically stimulated luminescence chronologies of the Oitavos consolidated dune (Western Portugal)
The dune of Oitavos, the underlying paleosol, and Helix sp. gastropod shells found within the paleosol were dated using a combination of radiocarbon and blue optically stimulated luminescence (OSL). The organic component of the paleosol produced a significantly older age (~20,000 cal BP) than the OSL age measurement (~15,000 yr), while 14C age measurements on the inorganic component and the gastropods produced ages of ~35,000 yr and ~34,000 yr, respectively. Rare-earth
element analyses provide evidence that the gastropods incorporate geological carbonate, making them an unreliable indicator of the age of the paleosol. We propose that the 14C age of the small organic component of the paleosol is also likely to be unreliable due to incorporation of residual material. The OSL age measurement of the upper paleosol (~15,000 yr) is consistent with the age for the base of the dune (~14,500 yr). The younger OSL age for the top of the dune (~12,000 yr) suggests that it was built up by at least 2 sand pulses or that there was a remobilization of material at the top during its evolution, prior to consolidation
First Trimester Aneuploidy Screening Program for Preeclampsia Prediction in a Portuguese Obstetric Population
Objective. To evaluate the performance of a first trimester aneuploidy screening program for preeclampsia (PE) prediction in a Portuguese obstetric population, when performed under routine clinical conditions. Materials and Methods. Retrospective cohort study of 5672 pregnant women who underwent routine first trimester aneuploidy screening in a Portuguese university hospital from January 2009 to June 2013. Logistic regression-based predictive models were developed for prediction of PE based on maternal characteristics, crown-rump length (CRL), nuchal translucency thickness (NT), and maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) and free beta-subunit of human chorionic gonadotropin (free β-hCG). Results. At a false-positive rate of 5/10%, the detection rate for early-onset (EO-PE) and late-onset (LO-PE) PE was 31.4/45.7% and 29.5/35.2%, respectively. Although both forms of PE were associated with decreased PAPP-A, logistic regression analysis revealed significant contributions from maternal factors, free β-hCG, CRL, and NT, but not PAPP-A, for prediction of PE. Conclusion. Our findings support that both clinical forms of EO-PE and LO-PE can be predicted using a combination of maternal history and biomarkers assessed at first trimester aneuploidy screening. However, detection rates were modest, suggesting that models need to be improved with additional markers not included in the current aneuploidy screening programs
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