Natural Experiments
Mostrando 1-12 de 1065 artigos, teses e dissertações.
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1. INTERDISCIPLINARY EDUCATION THROUGH THE DEVELOPMENT OF A COST-EFFECTIVE PHOTOMETRIC PH METER SENSOR USING NATURAL PIGMENTS
There is a trend of development of analytical methodologies and technologies that allow in situ analysis, producing accurate information in real time, at low cost, using homemade experiments and devices to increase interest in scientific knowledge with a constructive approach in an interdisciplinary perspective in Chemistry Education. In this context, a phot
Química Nova. Publicado em: 2022
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2. Natural and Semisynthetic Triterpenes from Combretum leprosum Mart. with Antiplasmodial Activity
Malaria is responsible for thousands of deaths each year. Currently, artemisinin combination therapy (ACT) is used as first-choice medication against the disease. However, the emergence of resistant strains prompts the search for alternative compounds. The present study aimed to investigate the antiplasmodial activities of natural triterpenes (compounds 1 an
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. LEARNING ABOUT EDGE EFFECTS AND ULTRAMICROELECTRODES IN ELECTROCHEMISTRY: SYNERGY BETWEEN EXPERIMENTS AND SIMULATIONS
A short experimental activity aimed at upper level undergraduate students or beginner researchers is presented to introduce the concepts of edge effects and hemispherical diffusion at ultramicroelectrodes. Students will perform simple cyclic voltammetry experiments varying the scan rate and using disk electrodes with different radii. They are then asked to i
Quím. Nova. Publicado em: 2020-09
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4. 3-Aminofurostane Alkaloids from Solanum paniculatum (“Jurubeba Verdadeira”) Roots
The roots of Solanum paniculatum (Solanaceae) have extensively been used in folk medicine to treat liver infections and as a diuretic. Ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) were used for the profiling and structural characterization of alkaloids from the roots of S. paniculatum. Six
J. Braz. Chem. Soc.. Publicado em: 2020-05
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5. Dendrometric Analysis of Early Development of Eucalyptus urophylla x Eucalyptus grandis with Gypsum use Under Subtropical Conditions
ABSTRACT Gypsum can be used as a source for calcium (Ca) and sulphurum (S) for plants, as well as an acid, that is, a natural soil conditioner. Aiming to determine the influence of gypsum on the development of Eucalyptus urograndis in Brazil, an experiment was conducted at two locations in Paraná State. Experiments were conducted with rates of 0, 0.3, 0.6,
Floresta Ambient.. Publicado em: 20/01/2020
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6. Effects of Reduced and Conventional Tillage on Weed Communities: Results of a Long-Term Experiment in Southwestern Spain
RESUMO: Uma desvantagem importante na adoção de técnicas de cultivo mínimo (MT) e plantio direto (NT) é o deslocamento de plantas daninhas frequentemente observado, promovendo espécies adaptadas e, com isso, um controle de plantas daninhas mais precário. Essas mudanças só podem ser detectadas com experimentos de longo prazo, e os resultados podem di
Planta daninha. Publicado em: 02/12/2019
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7. Aplicação de solução semianalítica para modelagem de ensaios de sorção e difusão pura com lixiviado
RESUMO A implementação da Política Nacional de Resíduos Sólidos (Lei nº 12.305, de 2 de agosto de 2010) foi um marco para a disposição final e o tratamento de resíduos sólidos no país. A contaminação decorrente da negligência na disposição dos resíduos sólidos urbanos atinge sistemas naturais vitais para a existência humana. Torna-se, port
Eng. Sanit. Ambient.. Publicado em: 25/11/2019
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8. Bioaccumulation, Growth and Photosynthetic Response of a New Found in Bulgaria Invasive Species Lemna minuta and L. valdiviana to Heavy Metal Pollution
RESUMO: Metais pesados podem ser encontrados no meio ambiente como ingredientes naturais ou de práticas agrícolas, industriais e químicas. Este estudo foi conduzido com o objetivo de traçar o potencial das plantas aquáticas L. minuta e L. valdiviana para a bioacumulação de Cu, Cd e Pb a partir de água contaminada com baixos níveis desses elementos.
Planta daninha. Publicado em: 04/11/2019
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9. Pure line selection in a heterogeneous soybean cultivar
Abstract Although cultivars of autogamous plants are homogeneous genotypes, they may show natural variability due to mechanical mixing, natural hybridization, and mutation. The aim of the present study was to estimate genetic and phenotypic parameters and to identify and select superior genotypes that associate good performance in traits of interest from a h
Crop Breed. Appl. Biotechnol.. Publicado em: 31/10/2019
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10. Large deflection and initial instability analysis of anisotropic plates by the generalized finite element method
Abstract This paper presents investigations laminated plates under moderately large transverse displacements and initial instability, through the Generalized Finite Element Methods - GFEM. The von Kármán plate hypothesis are used along with Kirchhoff and Reissner-Mindlin kinematic plate bending models to approximate transverse displacements and critical bu
Lat. Am. j. solids struct.. Publicado em: 28/10/2019
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11. REVISITING THE NUCLEOPHILICITY CONCEPT IN A COMPREHENSIVE BIOMASS VALORIZATION EXPERIMENT: FROM PAPAYA SEEDS TO THIOUREA MOTIFS
The recovery of waste materials with potential for synthetic transformations is a major field in science. However, just few experiments have been devoted to undergraduate students by exploring some consistent subjects in light of simple, natural resources. Nucleophilicity is a central subject in chemistry and there are significant synthetic models to exploit
Quím. Nova. Publicado em: 21/10/2019
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12. Kinetic Analysis of Lead Removal by Natural Hydroxyapatite from Aqueous Solution in High Concentration
The aim of this work was to study of the kinetic of Pb(II) sorption, in high lead concentration aqueous solution, by the natural hydroxyapatite (HA) and to verify whether there is a different behavior between natural and synthetic HA under different lead concentrations. Batch experiments were carried out using solutions with high lead concentration, with the
Mat. Res.. Publicado em: 30/09/2019