Ensino remoto em tempos de pandemia: considerações sobre o ensino não presencial emergencial na Universidade Federal de São Carlos (UFSCAR): Remote education in pandemic times: considerations about the emergency Off-site teaching at the Universidade Federal de São Carlos (UFSCAR)

Por conta da pandemia da Covid-19, o ambiente universitário precisou adaptar suas atividades e o processo de ensino e aprendizagem. Na Universidade Federal de São Carlos (UFSCar), a experiência contraditória do ENPE trouxe diversas complicações e agravantes. Por meio da realização de entrevistas, questionários e do levantamento documental, bem como da participação observante em espaços de decisão institucionais e da experiência em oferecer, monitorar e participar de aulas realizadas de forma remota, buscamos apontar as características do ensino remoto, em geral, e das particularidades do ensino não-presencial emergencial, em específico, além de apontar algumas alternativas e possibilidades.&nbsp

Atrial fibrosis and decreased connexin 43 in rat hearts after exposure to high-intensity infrasound

Background: Noise is an important environmental risk factor. Industrial environments are rich in high-intensity infrasound (hi-IFS), which we have found to induce myocardial and coronary perivascular fibrosis in rats. The effects of exposure to IFS on the ventricles have been studied, but not on the atria. We hypothesized that rats exposed to hi-IFS develop atrial remodeling involving fibrosis and connexin 43, which we sought to evaluate. Material and methods: Seventy-two Wistar rats, half exposed to hi-IFS (120 dB, < 20 Hz) during a maximum period of 12 weeks and half age-matched controls, were studied. Atrial fibrosis was analyzed by Chromotropeaniline blue staining. The immunohistochemical evaluation of Cx43 was performed using the polyclonal antibody connexin-43 m diluted 1:1000 at 4 degrees C overnight. Digitized images were obtained with an optical microscope using 400 x magnifications. The measurements were performed using image J software. A two-way ANOVA model was used to compare the groups. Results: The mean values of the ratio "atrial fibrosis / cardiomyocytes" increased to a maximum of 0.1095 +/- 0,04 and 0.5408 +/- 0,01, and of the ratio "CX43 / cardiomyocytes" decreased to 0.0834 +/- 0,03 and 0.0966 +/- 0,03, respectively in IFS-exposed rats and controls. IFS-exposed rats exhibited a significantly higher ratio of fibrosis (p < .001) and lower ratio of Cx43 (p = .009). Conclusion: High-intensity infrasound exposure leads to an increase in atrial interstitial fibrosis and a decrease in connexin 43 in rat hearts. This finding reinforces the need for further experimental and clinical studies concerning the effects of exposure to infrasound

Effect of X-ray tube configuration on measurement of key soil fertility attributes with XRF

The successful use of energy-dispersive X-ray fluorescence (ED-XRF) sensors for soil analysis requires the selection of an optimal procedure of data acquisition and a simple modelling approach. This work aimed at assessing the performance of a portable XRF (XRF) sensor set up with two different X-ray tube configurations (combinations of voltage and current) to predict nine key soil fertility attributes: (clay, organic matter (OM), cation exchange capacity (CEC), pH, base saturation (V), and extractable nutrients (P, K, Ca, and Mg). An XRF, operated at a voltage of 15 kV (and current of 23 mu A) and 35 kV (and current of 7 mu A), was used for analyzing 102 soil samples collected from two agricultural fields in Brazil. Two different XRF data analysis scenarios were used to build the predictive models: (i) 10 emission lines of 15 keV spectra (EL-15), and (ii) 12 emission lines of 35 keV spectra (EL-35). Multiple linear regressions (MLR) were used for model calibration, and the models' prediction performance was evaluated using different figures of merit. The results show that although X-ray tube configuration affected the intensity of the emission lines of the different elements detected, it did not influence the prediction accuracy of the studied key fertility attributes, suggesting that both X-ray tube configurations tested can be used for future analyses. Satisfactory predictions with residual prediction deviation (RPD) >= 1.54 and coefficient of determination (R-2) >= 0.61 were obtained for eight out of the ten studied soil fertility attributes (clay, OM, CEC, V, and extractable K, Ca, and Mg). In addition, simple MLR models with a limited number of emission lines was effective for practical soil analysis of the key soil fertility attributes (except pH and extractable P) using XRF. The simple and transparent methodology suggested also enables future researches that seek to optimize the XRF scanning time in order to speed up the XRF analysis in soil samples

A simple and cheaper solution to calibrate microcomputer time base with NIST totalizer method / Uma solução simples e mais barata para calibrar a base de tempo do microcomputador com o método totalizador NIST

Normally, laboratories that need traceability of time quantity in measurements, find high cost and complex infrastructure to collect traceable time measurements and automation software. This paper shows the calibration of microcomputers in LNMRI laboratory, using a simple method proposed by Special Publication NIST 960-12, with a unique reference counter with an external time base by the CSAC cesium frequency standard and a virtual stopwatch that can be download on the internet. The totalizer method is a simple way to calibrate time offset dt/t, and the results show that the microcomputers can be used how a time base reference in measurements that required dimensionless fractional time uncertainty until microseconds for a second

Assessing soil key fertility attributes using a portable X-ray fluorescence : a simple method to overcome matrix effect

The matrix effect is one of the challenges to be overcome for a successful analysis of soil samples using X-ray fluorescence (XRF) sensors. This work aimed at evaluation of a simple modeling approach consisted of Compton normalization (CN) and multivariate regressions (e.g., multiple linear regressions (MLR) and partial least squares regression (PLSR)) to overcome the soil matrix effect, and subsequently improve the prediction accuracy of key soil fertility attributes. A portable XRF was used for analyzing 102 soil samples collected from two agricultural fields with contrasting soil matrices. Using the intensity of emission lines as input, preprocessing methods included with and without the CN. Univariate regression models for the prediction of clay, cation exchange capacity (CEC), and exchangeable (ex-) K and Ca were compared with the corresponding MLR models to assess matrix effect mitigation. The MLR and PLSR models improved the prediction results of the univariate models for both preprocessing methods, proving to be promising strategies for mitigating the matrix effect. In turn, the CN also mitigated part of the matrix effect for ex-K, ex-Ca, and CEC predictions, by improving the predictive performance of these elements when used in univariate and multivariate models. The CN has not improved the prediction accuracy of clay. The prediction performances obtained using MLR and PLSR were comparable for all evaluated attributes. The combined use of CN with multivariate regressions (MLR or PLSR) achieved excellent prediction results for CEC (R-2= 0.87), ex-K (R-2 >= 0.94), and ex-Ca (R-2 >= 0.96), whereas clay predictions were comparable with and without CN (0.89 <= R-2 <= 0.92). We suggest using multivariate regressions (MLR or PLSR) combined with the CN to remove the soil matrix effects and consequently result in optimal prediction results of the studied key soil fertility attributes. The prediction performance observed for this solution showed comparable results to the approach based on the preprogrammed measurement package tested (Geo Exploration package, Bruker AXS, Madison, WI, USA)

MANEJO COM INSETICIDAS VISANDO O CONTROLE DE PERCEVEJO MARROM NA SOJA INTACTA

Ao longo dos anos, verificaram-se grandes mudanças no sistema de produção de soja no Brasil. O percevejo marrom (Euschistus heros) é uma praga‑chave da cultura de soja. É a espécie mais abundante do complexo de percevejos apresentando-se em predominância no estado do Tocantins e em grande parte das regiões dos cerrados produtoras de soja. Objetivou-se com esse trabalho avaliar a eficiência de diferentes inseticidas utilizados no manejo de Euschistus heros na cultura da soja intacta. O experimento foi conduzido no ano agrícola 2014/2015 em condições de campo na Fazenda Pedrinha, situada no município de Porto Nacional – TO. O delineamento experimental foi de blocos casualizados, constituído de seis tratamentos com quatro repetições. Realizou-se amostragens com 0, 3, 7, 10 dias após aplicação, avaliando-se a eficiência de controle, porcentagem de dano causado por percevejo, massa de 1.000 grãos e produtividade de grãos. O inseticida Imidacloprido + Bifentrina foi superior na eficiência de controle e no efeito residual em relação aos demais. Todos os inseticidas aplicados promoveram um incremento em produtividade quando comparados à testemunha, observando uma menor porcentagem de dano causado por percevejo marrom

Avaliação multiambiental de híbridos de sorgo durante a entressafra no Brasil

The objective of this work was to simultaneously select pre-commercial grain sorghum hybrids with high adaptability and yield stability, through mixed modeling, in 20 environments, during six years. The evaluated plant material consisted of 57 commercial grain sorghum hybrids. In all experiments, hybrids were arranged in a triple lattice design; some experiments used a 6x6 lattice, and others, a 5x5 lattice. Adaptability and stability parameters were obtained based on the prediction by harmonic mean of the relative performance of genotypic values (HMRPGV). The mixed models proved to be adequate to analyze the genotype x environment (GxE) interaction and the genotypic adaptability and stability studies on grain sorghum. The hybrids that stand out, considering all environments are 1G282, A9904, 50A50, A9902, and XB6022. The A9904 hybrid stands out in favorable environments, with a grain yield above average. Only 1G282 is among the five best hybrids for each group of environments, and it is the best grain sorghum hybrid for yield performance, adaptability, and stability. The predicted genotypic values based on genotypic means can be used in the environments with the same GxE interaction pattern because they are free of the GxE interaction.O objetivo deste trabalho foi selecionar, simultaneamente, híbridos pré-comerciais de sorgo granífero com alta adaptabilidade e estabilidade da produção de grãos, por meio de modelagem mista, em 20 ambientes, por seis anos. O material vegetal avaliado consistia de 57 híbridos comerciais de sorgo granífero. Em todos os experimentos, os híbridos foram arranjados em delineamento fatorial triplo; alguns experimentos utilizaram um fatorial 6x6, e outros, um fatorial 5x5. Os parâmetros de adaptabilidade e estabilidade foram obtidos com base na predição por média harmônica da performance relativa dos valores genéticos (MHPRVG). Os modelos mistos mostraram-se adequados para analisar a interação genótipo x ambiente (GxE) e os estudos de adaptabilidade e estabilidade genotípica do sorgo granífero. Os híbridos que se destacam, considerando-se todos os ambientes, são 1G282, A9904, 50A50, A9902 e XB6022. O híbrido A9904 destaca-se em ambientes favoráveis, com rendimento de grãos acima da média. Apenas 1G282 está entre os cinco melhores híbridos para cada grupo de ambientes e é o melhor híbrido de sorgo granífero quanto ao rendimento, à adaptabilidade e à estabilidade. Os valores genotípicos preditos com base em médias genotípicas podem ser usados em relação aos ambientes com o mesmo padrão de interação GxE por estarem livres da interação GxE

Influência do óxido nítrico na germinação de sementes de Plathymenia reticulata Benth com baixo vigor

The objective of this study was to investigate the nitric oxide (NO) action on the promotion of seeds germination with low vigor of Plathymenia reticulata. Accelerated aging on seeds were made per 24, 48 and 72 hours at 40°C as well as pre soaking in potassium nitrate (KNO3) and sodium nitroprussiate (SNP) solutions. The concentrations from zero (control), 0,01, 0,10, 1,0 and 10,0mMol.l-1 per six, 12, 18, and 24 hours were used. The accelerated aging period were followed by pre soaking in KNO3 and SNP. The electric conductivity and the activities of the enzymes superoxide dismutase (SOD) and catalase (CAT) were quantified. The best results of germination occurred with the pre soaked seeds in KNO3 and SNP during 24 hours and in 0,10mMol.l-1. The KNO3 and the SNP increased the germination of the aged seeds of P. reticulate. The accelerated aging increased the membrane permeability, which was reduced with the KNO3 and SNP treatments. The activity of SOD was greater in seeds treated with KNO 3 and SNP. The CAT activity did not show significant differences among the treatments, even when the seeds were soaked in KNO3 and SNP. It can be concluded that the nitric oxide increased the quality of the aged seeds by maintaining the membrane integrity and stimulus of the superoxide dismutase activity

Estudo enzimático da deterioração de sementes de melanoxylon brauna submetidas ao envelhecimento natural e acelerado

There is no specific knowledge of forest tree seeds regarding the metabolic processes involved during storage which makes the establishment of techniques for their suitable conservation difficult. The object of the present research was to study the role of oxidative stress enzymes and fat metabolism during storage and artificial ageing. Seeds of Melanoxylon brauna - Leguminosae- Caesalpinodeae (brauna) were naturally aged during storage for 0, 3, 6, 9 and 12 months in a cold chamber, and artificially aged (accelerated ageing) during 0, 24, 48, 72 and 96 hours, in order to evaluate the changes in the activity of the enzymes superoxide dismutase and catalase and also the oil content. Germination tests were made and the enzymatic activity and quantification of fat content were measured in the embryonary axis and cotyledons. The natural and accelerated ageing affected the behavior of the seeds in a similar manner causing a reduction in vigour. Although the artificial and natural ageing of the seeds affected the germination in a similar way, the accelerated ageing at 45 °C for 72 hours adequately simulated the enzymatic behavior as demonstrated by the seeds stored for 12 months in the cold chamber. There was a similar gradual reduction in the fat reserves in both ageing systems but without any correlation between natural storage and accelerated ageing

Modelagem da proteção do solo por plantas de cobertura no sul de Minas Gerais.

A cobertura do solo é o fator de maior importância relativa no controle da erosão hídrica. Assim, objetivou-se no presente estudo elaborar a modelagem da cobertura vegetal de vinte e quatro plantas de cobertura, em diversos sistemas de plantio e históricos de uso, com potencial para cultivo no Sul de Minas Gerais. Para avaliação da cobertura vegetal foram realizadas avaliações no campo utilizando uma régua de classificação da cobertura vegetal, sendo o delineamento experimental inteiramente casualizado, com três repetições, utilizado neste experimento. As plantas cultivadas sobre a palhada de feijão irrigado apresentaram alto índice de cobertura do solo, o que pode estar relacionado à maior disponibilidade de nutrientes deixado por esta cultura na palhada e a maior reserva de água no solo, promovido pela irrigação do feijão. O milheto cultivado em nível e sobre a palhada de milheto e feijão-de-porco apresentou o menor índice de cobertura entre as plantas testadas. Na região sul de Minas Gerais os padrões de chuvas ocorrem em maior quantidade nos períodos de outubro a março, com elevação em dezembro e janeiro. Neste período o solo deve estar protegido do impacto da gota de chuva, pois o risco de erosão hídrica é maior. Assim, a utilização das plantas de cobertura é de grande importância, pois estas protegem o solo do impacto direto das gotas de chuvas e diminuem os picos de temperatura do solo, sendo que estas devem ser cultivadas, preferencialmente, sobre a palhada de feijão