Shrinkage capacity (caráter retrátil in Portuguese) is a new diagnostic characteristic recently introduced in the Brazilian System of Soil Classification (SiBCS) to indicate shrink and swell properties observed in subtropical soils from highland plateaus in southern Brazil, specifically in Oxisols with brown colors. In soils located in road cuts exposed to drying for some weeks, strong shrinkage of soil volume is observed in these soils, resulting in the formation of pronounced vertical cracks and large and very large prismatic structures, which crumble in blocks when handled. We hypothesize that such properties are related to their clay mineralogy, although there are no conclusive studies about this, the motive for the present study. Samples of the A and B horizons from six Oxisols with expansive capacity from the states of Santa Catarina and Rio Grande do Sul were analyzed. One Rhodic Hapludox, from the state of Paraná, without expansive capacity, was used for comparison. All the soils are very clayey, originated from basalt, and have similar iron oxide content. For identification of clay mineralogy, X-ray diffraction techniques were employed, together with the use of NEWMOD ® software to investigate and describe the interstratified minerals. The resultsshowed that most expansive soils have a similar mineralogical composition, with kaolinite, interstratified kaolinite-smectite (K-S), and hydroxy-Al interlayered smectites (HIS), unlike the non-expansive Rhodic Hapludox, which exhibited kaolinite with significant amounts of gibbsite and low amount of interstratified K-S. According to the mineralogical assemblage identified in the expansive soils, we can affirm that the mechanism of smectite expansion and contraction is related to the shrinkage capacity of the soil, considering that the level of hydroxy-Al intercalation is low. In addition, these mechanisms also are related to the presence of quasicrystals and domains that control the water dynamic in the smectites, contributing to shrinkage capacity.
Autism spectrum disorder (ASD) is a neuropsychiatric disorder characterized by the impairment in the social reciprocity, interaction/language, and behavior, with stereotypes and signs of sensory function deficits. Electroencephalography (EEG) is a well-established and noninvasive tool for neurophysiological characterization and monitoring of the brain electrical activity, able to identify abnormalities related to frequency range, connectivity, and lateralization of brain functions. This research aims to evidence quantitative differences in the frequency spectrum pattern between EEG signals of children with and without ASD during visualization of human faces in three different expressions: neutral, happy, and angry. Quantitative clinical evaluations, neuropsychological evaluation, and EEG of children with and without ASD were analyzed paired by age and gender. The results showed stronger activation in higher frequencies (above 30 Hz) in frontal, central, parietal, and occipital regions in the ASD group. This pattern of activation may correlate with developmental characteristics in the children with ASD.
Brown Nitossolos (Nitisols) and Latossolos (Ferralsols), according to the Brazilian System of Soil Classification (SiBCS), have a "caráter retrátil" as their distinctive property. Because this is a new topic, it is necessary to propose methods for evaluation. The objectives of this study were to evaluate methodologies for quantifying the shrinkage of soil using the Syringe Method and the Metallic Mercury Method, and to propose a new one, the "Ring with Sand Method". Soil samples from eight pedons were used, with six Nitossolos and Latossolos with shrinkage, a Latossolo without shrinkage, and a Vertissolo (Vertissol) with admittedly high shrinkage and expansion. The methods were effective in identifying the greater degree of shrinkage of the Vertissolo. However, the Ring with Sand Method was the only one to indicate significant differences between the Vertissolo and the Latossolo without shrinkage, and this method differentiated the shrinkable soils as to the intensity of the characteristic. The proposed method was effective and can serve as a standard to quantify shrinkage.
O processo de urbanização rápido e desordenado trouxe consequências na dinâmica dos elementos naturais responsáveis pelas condições de qualidade ambiental, tais como solo, temperatura, flora e fauna. Neste sentido, a arborização viária adquire importância como um dos fatores ligados a qualidade de vida da população. O objetivo desse trabalho foi avaliar a condição da arborização viária do bairro Santa Terezinha em Pato Branco (PR). Foram analisadas todas as árvores presentes nas ruas do bairro, com diâmetro a altura do peito igual ou maior de 0,10 metros. As espécies foram identificadas e avaliadas quanto ao tipo de poda, presença de injúrias, área livre de pavimentação no entorno das árvores e altura da primeira bifurcação. Foram verificados 586 espécimes arbóreos no bairro analisado, compreendendo 31 espécies diferentes, contudo houve a predominância da espécie Ligustro lucidum com 43,51% de frequência, seguida de Lagerstroemia indica com 15,18%. Dos exemplares arbóreos identificados, 83,18% eram de espécies exóticas, e destas 48,45% tinham o agravante de serem invasoras da região fitogeográfica local. Foi verificado que 62% das árvores não haviam recebido poda e que entre as podas executadas a poda drástica foi a mais verificada com 22% das observações. A maioria das injúrias observadas estava localizada no caule das plantas e na maioria dos casos eram provenientes da execução das podas, 46,75% dos espécimes apresentavam-se sob
Estudos recentes apontaram que o principal fator de origem do caráter retrátil, observado em Latossolos e Nitossolos, não é a mineralogia. Com isso formulou-se a hipótese de que a retração do solo em Latossolos e Nitossolos tem origem em fatores estruturais do solo, portanto podem ser investigados indiretamente através das propriedades físicas da estrutura do solo. Sendo assim o objetivo deste trabalho foi relacionar a retração com propriedades físicas e a matéria orgânica do solo, investigando de maneira indireta o processo de retração do solo. Foram selecionados seis perfis coletados nos Estados de Santa Catarina e no Rio Grande do Sul que apresentam caráter retrátil e um Vertissolo Ebânico no Rio Grande do Sul. Foram avaliados: granulometria, limites de consistência, densidade do solo e de partículas, porosidade total, microporos e macroporos, área superficial específica, índice de retração, matéria orgânica do solo e retenção de água no solo. A relação entre as propriedades foi realizada através de análise de componentes principais (ACP). Adicionalmente, para analisar o efeito da estrutura e da matéria orgânica no índice de retração, e amostras foram coletadas nos horizontes A, AB, BA, Bt1, Bt2, Bt3 do Nitossolo Bruno de Painel, o qual possui um gradiente natural de decréscimo de matéria orgânica no perfil. Neste, as determinações da curva de retenção e índice de retração foram realizadas com amostras de estrutura preservada e alterada. A ACP indicou o índice plasticidade com maior relação com a retração do solo, indicando que a redução do teor de água cria meniscos entre as partículas assim a tensão superficial aumenta, causando uma curvatura do menisco, na interface entre água e ar aproximando as partículas, causando assim a retração do solo. A matéria orgânica tem efeito direto no processo de retração, no entanto, a intensidade da retração é dependente da estruturação do solo.
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