113 research outputs found
Curva de dose resposta para atividade residual do herbicida diclosulam em girassol.
O bioensaio é um método de menor custo e de maior simplicidade para estimativa de resíduo de herbicida no solo. O herbicida diclosulam é um produto muito utilizado na agricultura pela sua eficiência no manejo de plantas daninhas, porém, o mesmo apresenta grande capacidade residual. O girassol (Helianthus annuus) é uma espécie bastante sensível ao diclosulam, podendo ser utilizado como planta bioindicadora
Avaliação do carvão ativado de endocarpo de macaúba como potencial biorremediador em solos contaminados com o diclosulam.
A contaminação dos solos por herbicidas representa um grande problema ambiental e tem impactos significativos na economia e na saúde pública. Nesse contexto, a biorremediação surge como uma técnica promissora para a recuperação de solos contaminados
Comunicación con los padres, malestar psicológico y actitud hacia la autoridad en adolescentes mexicanos: su influencia en la victimización escolar
Las consecuencias de la victimización escolar en los adolescentes demandan una mayor comprensión de las relaciones entre los factores involucrados. Se seleccionó una muestra representativa y aleatoria por conglomerados, que incluía 1.698 estudiantes mexicanos de Secundaria (46% niños y 54% niñas), de 12 a 17 años (M = 13.65. DE = 1.14). Los datos de auto-reporte sobre comunicación con los padres, malestar psicológico y actitud positiva hacia la autoridad institucional se analizaron con la técnica del análisis estructural. El modelo estructural resultante confirmó una relación indirecta de la comunicación padres-adolescentes con la victimización escolar, a través del malestar psicológico y la actitud positiva hacia la autoridad institucional, demostrando la influencia de la calidad de la comunicación con sus padres sobre la victimización escolar de los adolescentes.Consequences of adolescent's school victimization compel a better understanding of the relations between infl uential factors. A randomized representative sample, was selected by conglomerates, including 1.698 Mexican adolescents (46% boys and 54% girls), with ages between 12-17 years (M = 13.65. SD = 1.14) attending secondary school. Self-report data about parents- adolescent communication, psychological distress and positive attitude toward institutional authority were analyzed using structural analysis. The resulting path structural model confi rmed an indirect relation between parents-adolescent communication and school victimization trough psychological distress and a positive attitude toward institutional authority, underscoring the influence of parents-adolescent communication over adolescent`s school victimization
Update of the list of QPS-recommended biological agents intentionally added to food or feed as notified to EFSA 15: suitability of taxonomic units notified to EFSA until September 2021
The qualified presumption of safety (QPS) approach was developed to provide a generic pre-evaluation of the safety of biological agents. The QPS approach is based on an assessment of published data for each agent, with respect to its taxonomic identity, the body of relevant knowledge and safety concerns. Safety concerns are, where possible, confirmed at the species/strain or product level and reflected by ‘qualifications’. The QPS list was updated in relation to the revised taxonomy of the genus Bacillus, to synonyms of yeast species and for the qualifications ‘absence of resistance to antimycotics’ and ‘only for production purposes’. Lactobacillus cellobiosus has been reclassified as Limosilactobacillus fermentum. In the period covered by this statement, no new information was found that would change the status of previously recommended QPS taxonomic units (TU)s. Of the 70 microorganisms notified to EFSA, 64 were not evaluated: 11 filamentous fungi, one oomycete, one Clostridium butyricum, one Enterococcus faecium, five Escherichia coli, one Streptomyces sp., one Bacillus nakamurai and 43 TUs that already had a QPS status. Six notifications, corresponding to six TUs were evaluated: Paenibacillus lentus was reassessed because an update was requested for the current mandate. Enterococcus lactis synonym Enterococcus xinjiangensis, Aurantiochytrium mangrovei synonym Schizochytrium mangrovei, Schizochytrium aggregatum, Chlamydomonas reinhardtii synonym Chlamydomonas smithii and Haematococcus lacustris synonym Haematococcus pluvialis were assessed for the first time. The following TUs were not recommended for QPS status: P. lentus due to a limited body of knowledge, E. lactis synonym E. xinjiangensis due to potential safety concerns, A. mangrovei synonym S. mangrovei, S. aggregatum and C. reinhardtii synonym C. smithii, due to lack of a body of knowledge on its occurrence in the food and feed chain. H. lacustris synonym H. pluvialis is recommended for QPS status with the qualification ‘for production purposes only’
Comparative analysis of three different development phases of Meloidogyne incognita by two-dimensional electrophoresis.
Influence of the Water Content on the Diffusion Coefficients of Li⁺ and Water across Naphthalenic Based Copolyimide Cation-Exchange Membranes
The transport of lithium ions in cation-exchange membranes based on sulfonated copolyimide membranes is reported. Diffusion coefficients of lithium are estimated as a function of the water content in membranes by using pulsed field gradient (PFG) NMR and electrical conductivity techniques. It is found that the lithium transport slightly decreases with the diminution of water for membranes with water content lying in the range 14 < λ < 26.5, where λ is the number of molecules of water per fixed sulfonate group. For λ < 14, the value of the diffusion coefficient of lithium experiences a sharp decay with the reduction of water in the membranes. The dependence of the diffusion of lithium on the humidity of the membranes calculated from conductivity data using Nernst–Planck type equations follows a trend similar to that observed by NMR. The possible explanation of the fact that the Haven ratio is higher than the unit is discussed. The diffusion of water estimated by 1H PFG-NMR in membranes neutralized with lithium decreases as λ decreases, but the drop is sharper in the region where the decrease of the diffusion of protons of water also undergoes considerable reduction. The diffusion of lithium ions computed by full molecular dynamics is similar to that estimated by NMR. However, for membranes with medium and low concentration of water, steady state conditions are not reached in the computations and the diffusion coefficients obtained by MD simulation techniques are overestimated. The curves depicting the variation of the diffusion coefficient of water estimated by NMR and full dynamics follow parallel trends, though the values of the diffusion coefficient in the latter case are somewhat higher. The WAXS diffractograms of fully hydrated membranes exhibit the ionomer peak at q = 2.8 nm⁻1, the peak being shifted to higher q as the water content of the membranes decreases. The diffractograms present additional peaks at higher q, common to wet and dry membranes, but the peaks are better resolved in the wet membranes. The ionomer peak is not detected in the diffractograms of dry membranes.The authors acknowledge financial support provided by the DGICYT (Dirección General de Investigación Cientifíca y Tecnológica) through Grant MAT2011-29174-C02-02
Land use change impacts on floods at the catchment scale: Challenges and opportunities for future research
Research gaps in understanding flood changes at the catchment scale caused by changes in forest management, agricultural practices, artificial drainage and terracing are identified. Potential strategies in addressing these gaps are proposed, such as complex systems approaches to link processes across time scales, long-term experiments on physical-chemical-biological process interactions, and a focus on connectivity and patterns across spatial scales. It is suggested that these strategies will stimulate new research that coherently addresses the issues across hydrology, soil and agricultural sciences, forest engineering, forest ecology and geomorphology
Relações da anatomia radicular na absorção, no acúmulo e na tolerância ao chumbo em Echinodorus grandiflorus
Adição de ácido cítrico potencializa a ação de ácidos húmicos e altera o perfil protéico da membrana plasmática em raízes de milho
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