Verificação da resistência do concreto “in loco”: métodos de ensaios mais usuais

A resistência à compressão do concreto é o principal parâmetro característico físico deste, torna-se uma necessidade importante para qualquer estrutura de concreto. No Brasil, os ensaios devidamente regulamentados pela ABNT para este fim são o Ensaio de compressão de corpos de prova, Extração de testemunho, Esclerometria e o Ensaio de Ultrassom. Nesse sentido o presente artigo além de abordar esses ensaios, também aponta a importância de fazer a rastreabilidade no concreto, a fim de manter um controle tecnológico que atenda às necessidades de qualquer tipo de construção, sendo ela, de pequena, médio ou grande porte. Mediante ao auxílio de uma pesquisa de campo descritiva, coletou-se informações sobre várias empresas na cidade de Mossoró-RN, com a finalidade de identificar quais os métodos praticados por essas empresas. Pós-coleta de dados procurou-se realizar um comparativo entre as empresas e consequentemente a elaboração de gráficos para facilitar o entendimento e mostrar o aspecto geral de algumas empresas atuantes na região. Após a análise dos resultados, encontrou-se uma diferença nessa realidade, indicando que nem todas as empresas entrevistadas realizam ensaios complementares em suas estruturas depois de executada

Unemployment Convergence in Central and Eastern European Countries: Driving Forces and Cluster Behavior

Employing a nonlinear logistic smooth transition autoregression system and comovement analysis, we find that the German business cycle has acted as a common driver affecting the cyclical behavior of unemployment rates in Central and Eastern European countries. In addition, we identify two convergence clubs in unemployment dynamics. The first comprises the Baltic States, Hungary, and Poland, and the second group of countries is composed of the Czech Republic and Slovakia. Interestingly, this classification matches the labor market policies and institutional divergences observed among these countries

Atmospheric turbulent structures and fire sweeps during shrub fires and implications for flaming zone behaviour

Background. Wildfires propagate through vegetation exhibiting complex spread patterns modulated by ambient atmospheric wind turbulence. Wind gusts at the fire-front extend and intensify flames causing direct convective heating towards unburnt fuels resulting in rapid acceleration of spread. Aims. To characterise ambient and fire turbulence over gorse shrub and explore how this contributes to fire behaviour. Methods. Six experimental burns were carried out in Rakaia, New Zealand under varying meteorological conditions. The ignition process ensured a fire-line propagating through dense gorse bush (1 m high). Two 30-m sonic anemometer towers measured turbulent wind velocity at six different levels above the ground. Visible imagery was captured by cameras mounted on uncrewed aerial vehicles at 200 m AGL. Key results. Using wavelet decomposition, we identified different turbulent time scales that varied between 1 and 128 s relative to height above vegetation. Quadrant analysis identified statistical distributions of atmospheric sweeps (downbursts of turbulence towards vegetation) with sustained events emanating from above the vegetation canopy and impinging at the surface with time scales up to 10 s. Conclusions. Image velocimetry enabled tracking of ‘fire sweeps’ and characterised for the first time their lifetime and dynamics in comparison with overlying atmospheric turbulent structures. Implications. This methodology can provide a comprehensive toolkit when investigating coupled atmosphere–fire interactions

TAREFA DICÓTICA EM IDOSOS: UM ESTUDO DE COMPARAÇÕES

Objetivo: comparar o desempenho entre idosos com acuidade periférica normal e com perda auditiva sensorioneural de grau leve nos testes de Identificação de Sentenças Dicóticas (DSI) e no Teste Dicótico de Dígitos (TDD). Métodos: participaram deste estudo 52 idosos, com idades entre 60 e 76 anos, apresentando limiares auditivos dentro dos padrões de normalidade (Grupo 1) e perda auditiva sensorioneural de grau leve (Grupo 2), curva timpanométrica do tipo A, reflexos acústicos contralaterais presentes e queixa de dificuldade de compreensão de fala. Os indivíduos foram submetidos a uma avaliação audiológica básica para caracterizar a audição periférica e, posteriormente, aos testes DSI (nas etapas de escuta direcionada e integração binaural) e TDD (na etapa de integração binaural). Resultados: no TDD houve diferença entre os grupos, com melhores resultados para o grupo de idosos normo-ouvintes. Para o teste DSI, não houve diferença no desempenho dos idosos entre os grupos. Conclusão: os idosos com acuidade periférica normal apresentaram melhor desempenho no TDD quando comparados aos idosos com perda auditiva sensorioneural de grau leve, já no teste DSI não houve diferença significativa entre os grupos

Variable frequency of LRRK2 variants in the Latin American research consortium on the genetics of Parkinson's disease (LARGE-PD), a case of ancestry

ABSTARCT: Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2), primarily located in codons G2019 and R1441, represent the most common genetic cause of Parkinson's disease in European-derived populations. However, little is known about the frequency of these mutations in Latin American populations. In addition, a prior study suggested that a LRRK2 polymorphism (p.Q1111H) specific to Latino and Amerindian populations might be a risk factor for Parkinson's disease, but this finding requires replication. We screened 1734 Parkinson's disease patients and 1097 controls enrolled in the Latin American Research Consortium on the Genetics of Parkinson's disease (LARGE-PD), which includes sites in Argentina, Brazil, Colombia, Ecuador, Peru, and Uruguay. Genotypes were determined by TaqMan assay (p.G2019S and p.Q1111H) or by sequencing of exon 31 (p.R1441C/G/H/S). Admixture proportion was determined using a panel of 29 ancestry informative markers. We identified a total of 29 Parkinson's disease patients (1.7%) who carried p.G2019S and the frequency ranged from 0.2% in Peru to 4.2% in Uruguay. Only two Parkinson's disease patients carried p.R1441G and one patient carried p.R1441C. There was no significant difference in the frequency of p.Q1111H in patients (3.8%) compared to controls (3.1%; OR 1.02, p = 0.873). The frequency of LRRK2-p.G2019S varied greatly between different Latin American countries and was directly correlated with the amount of European ancestry observed. p.R1441G is rare in Latin America despite the large genetic contribution made by settlers from Spain, where the mutation is relatively common

Detecting the effects of hydrocarbon pollution in the Amazon forest using hyperspectral satellite images

The global demand for fossil energy is triggering oil exploration and production projects in remote areas of the world. During the last few decades hydrocarbon production has caused pollution in the Amazon forest inflicting considerable environmental impact. Until now it is not clear how hydrocarbon pollution affects the health of the tropical forest flora. During a field campaign in polluted and pristine forest, more than 1100 leaf samples were collected and analysed for biophysical and biochemical parameters. The results revealed that tropical forests exposed to hydrocarbon pollution show reduced levels of chlorophyll content, higher levels of foliar water content and leaf structural changes. In order to map this impact over wider geographical areas, vegetation indices were applied to hyperspectral Hyperion satellite imagery. Three vegetation indices (SR, NDVI and NDVI705) were found to be the most appropriate indices to detect the effects of petroleum pollution in the Amazon forest

Huntingtin facilitates polycomb repressive complex 2

Huntington's disease (HD) is caused by expansion of the polymorphic polyglutamine segment in the huntingtin protein. Full-length huntingtin is thought to be a predominant HEAT repeat α-solenoid, implying a role as a facilitator of macromolecular complexes. Here we have investigated huntingtin's domain structure and potential intersection with epigenetic silencer polycomb repressive complex 2 (PRC2), suggested by shared embryonic deficiency phenotypes. Analysis of a set of full-length recombinant huntingtins, with different polyglutamine regions, demonstrated dramatic conformational flexibility, with an accessible hinge separating two large α-helical domains. Moreover, embryos lacking huntingtin exhibited impaired PRC2 regulation of Hox gene expression, trophoblast giant cell differentiation, paternal X chromosome inactivation and histone H3K27 tri-methylation, while full-length endogenous nuclear huntingtin in wild-type embryoid bodies (EBs) was associated with PRC2 subunits and was detected with trimethylated histone H3K27 at Hoxb9. Supporting a direct stimulatory role, full-length recombinant huntingtin significantly increased the histone H3K27 tri-methylase activity of reconstituted PRC2 in vitro, and structure–function analysis demonstrated that the polyglutamine region augmented full-length huntingtin PRC2 stimulation, both in HdhQ111 EBs and in vitro, with reconstituted PRC2. Knowledge of full-length huntingtin's α-helical organization and role as a facilitator of the multi-subunit PRC2 complex provides a novel starting point for studying PRC2 regulation, implicates this chromatin repressive complex in a neurodegenerative disorder and sets the stage for further study of huntingtin's molecular function and the impact of its modulatory polyglutamine region

The Polycomb Repressive Complex 2 Is a Potential Target of SUMO Modifications

The Polycomb Repressive Complex 2 (PRC2) functions as a transcriptional repressor through a mechanism that involves methylation of Histone H3 at lysine 27. The PRC2 complex activity is essential for cellular proliferation, development, and cell fate decisions. PRC2 target genes include important regulators of development and proliferation as well as tumor suppressor genes. Consistent with this, the activity of several Polycomb group (PcG) proteins is deregulated in human cancer suggesting an important role for PcGs in tumor development. Whereas the downstream functions of PcGs are well characterized, the mechanisms of their recruitment to target genes and the regulation of their activity are not fully understood.Here we show that the two PRC2 components SUZ12 and EZH2 are sumoylated in vitro and in vivo. Among several putative sumoylation sites we have mapped the major site of SUZ12 sumoylation. Furthermore, we show that SUZ12 interacts with the E2-conjugating enzyme UBC9 both in vitro and in vivo and that mutation of the SUZ12 sumoylation site does not abolish this binding. Finally, we provide evidence that the E3-ligase PIASXbeta interacts and enhances the sumoylation of SUZ12 in vivo suggesting that PIASXbeta could function as an E3-ligase for SUZ12.Taken together, our data identify sumoylation as a novel post-translational modification of components of the PRC2 complex, which could suggest a potential new mechanism to modulate PRC2 repressive activity. Further work aimed to identify the physiological conditions for these modifications will be required to understand the role of SUZ12 and EZH2 sumoylation in PcG-mediated epigenetic regulation of transcription