989 resultados para viés interpretativo


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Tese (doutorado)—Universidade de Brasília, Universidade Federal da Paraíba, Universidade Federal do Rio Grande do Norte, Programa Multi-Institucional e Inter-Regional de Pós-Graduação em Ciências Contábeis, 2016.

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El presente estudio, de carácter etnográfico, tiene lugar en el contexto de un aula de Educación Infantil con el objeto de registrar en detalle y analizar reflexivamente las características de las prácticas de enseñanza que propician el desarrollo del pensamiento matemático de los niños y las niñas, y su consecuente expresión en situaciones cotidianas. En este sentido, interesa interpretar y comprender la diversidad infantil -tanto a nivel de pensamiento como de formas para expresarlo- en relación con las argumentaciones que eligen para justificar sus decisiones; la formulación de sus descubrimientos o resoluciones originales; la confrontación de ideas con adultos y entre iguales; etc. ante situaciones que les plantean problemas u obstáculos a resolver que, por el “significado pragmático” en que se encuadran, invitan a los niños y niñas a aceptar el desafío de interpretar lo que está sucediendo y buscar soluciones. El trabajo de campo se asienta en la convicción de que la población infantil reelabora, en interacción cooperativa con otros, conocimientos matemáticos relacionados con los obstáculos cognitivos que están inmersos en las distintas situaciones a la que se enfrenta (reales, realistas y/o imaginarias). Al tiempo, se retroalimenta en la incertidumbre respecto a cómo, cuándo y en qué circunstancias se afianzan estos procesos. Por tanto, con una mirada etnográfica, el estudio busca respuestas recogiendo, analizando e interpretando información a lo largo de los 3 años de escolaridad que atraviesa un grupo de Educación Infantil escolarizado en el Centro de Educación Infantil y Primaria Las Cigüeñas, en la localidad madrileña de Rivas Vaciamadrid. La investigadora asume, a su vez, el papel docente de este grupo infantil, situación que aporta condiciones óptimas para mantener una estancia prolongada e intensiva en el campo de estudio con el objeto de registrar los sucesos matemáticos, planificados ad hoc o surgidos de forma espontánea, que acontecen durante el proceso de observación participante. La interpretación de los datos registrados permitió comprender -admitiendo que, la localidad de los mismos no permite extrapolarlos a toda la población infantil- la potencialidad de las prácticas de enseñanza para fomentar, o no, el interés de niños y niñas por utilizar, en situaciones contextualizadas, sus respectivos conocimientos matemáticos (propios del campo aritmético, geométrico y/o algebraico) marcados, obviamente, por la diversidad (en los estilos cognitivos, las formas de expresión, los intereses y motivaciones, etc.).

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Assim como o aprimoramento metodológico das ciências naturais (Newton, Humboldt, Darwin, etc.) permitiu-nos compreender o conjunto de leis que regem os processos físicos e orgânicos, o pensamento marxista, herdeiro das mais avançadas idéias até então elaboradas, viabilizou o estudo das distintas formas de sociedade ao desvendar seus mecanismos de funcionamento explicitando o caráter universal de determinadas leis econômicas e trajetórias de desenvolvimento. A utilização do potencial explicativo do materialismo histórico e dialético, bem como sua constante renovação, passa pela compreensão das categorias de formação social e modo de produção, as principais articuladoras de todas as noções teóricas caras ao marxismo. O trabalho em questão apresenta reflexões sobre o paradigma interpretativo de formação social, formulado por K. Marx, utilizado e aperfeiçoado por importantes intelectuais filiados ao pensamento marxista como V.I. Lenin (O desenvolvimento do capitalismo na Rússia) e A. Gramsci (A questão meridional), no caso latino-americano J.C. Mariátegui (7 ensaios de interpretação da realidade peruana) e I. Rangel (História da dualidade brasileira), e vinculado à Geografia por destacados pesquisadores brasileiros como Armen Mamigonian e Milton Santos.

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Assim como o aprimoramento metodológico das ciências naturais (Newton, Humboldt, Darwin, etc.) permitiu-nos compreender o conjunto de leis que regem os processos físicos e orgânicos, o pensamento marxista, herdeiro das mais avançadas idéias até então elaboradas, viabilizou o estudo das distintas formas de sociedade ao desvendar seus mecanismos de funcionamento explicitando o caráter universal de determinadas leis econômicas e trajetórias de desenvolvimento. A utilização do potencial explicativo do materialismo histórico e dialético, bem como sua constante renovação, passa pela compreensão das categorias de formação social e modo de produção, as principais articuladoras de todas as noções teóricas caras ao marxismo. O trabalho em questão apresenta reflexões sobre o paradigma interpretativo de formação social, formulado por K. Marx, utilizado e aperfeiçoado por importantes intelectuais filiados ao pensamento marxista como V.I. Lenin (O desenvolvimento do capitalismo na Rússia) e A. Gramsci (A questão meridional), no caso latino-americano J.C. Mariátegui (7 ensaios de interpretação da realidade peruana) e I. Rangel (História da dualidade brasileira), e vinculado à Geografia por destacados pesquisadores brasileiros como Armen Mamigonian e Milton Santos. A� io�_@ ?desenvolve esta pesquisa que, aqui, expressa parte de seus resultados.  

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Este trabajo trata sobre el proceso de regionalizacion en la zona del Pacifico Norte de Costa Rica.

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Ultrafast pump-probe spectroscopy is a conceptually simple and versatile tool for resolving photoinduced dynamics in molecular systems. Due to the fast development of new experimental setups, such as synchrotron light sources and X-ray free electron lasers (XFEL), new spectral windows are becoming accessible. On the one hand, these sources have enabled scientist to access faster and faster time scales and to reach unprecedent insights into dynamical properties of matter. On the other hand, the complementarity of well-developed and novel techniques allows to study the same physical process from different points of views, integrating the advantages and overcoming the limitations of each approach. In this context, it is highly desirable to reach a clear understanding of which type of spectroscopy is more suited to capture a certain facade of a given photo-induced process, that is, to establish a correlation between the process to be unraveled and the technique to be used. In this thesis, I will show how computational spectroscopy can be a tool to establish such a correlation. I will study a specific process, which is the ultrafast energy transfer in the nicotinamide adenine dinucleotide dimer (NADH). This process will be observed in different spectral windows (from UV-VIS to X-rays), accessing the ability of different spectroscopic techniques to unravel the system evolution by means of state-of-the-art theoretical models and methodologies. The comparison of different spectroscopic simulations will demonstrate their complementarity, eventually allowing to identify the type of spectroscopy that is best suited to resolve the ultrafast energy transfer.

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Obiettivo: valutare l’effetto del tilt pelvico rispetto all’antiversione del collo femorale, all’antiversione dell’acetabolo e all’adattamento dell’anca nei tre piani dello spazio secondo il concetto dell’interdipendenza regionale. Metodi: si sono scelti gli studi conformi con il P.E.O di ricerca: Popolazione = tutti, Esposizione = modificazioni del tilt pelvico, Outcome = aumento/diminuzione dell’antiversione dell’acetabolo, del collo femorale e del rom dell’anca nei tre piani dello spazio. Risultati: otto studi sono stati suddivisi in tre gruppi: Il primo gruppo permette di osservare l’effetto del tilt pelvico rispetto all’antiversione dell’acetabolo e alla mobilità dell’anca, facendo emergere che la retroversione del bacino aumenta l’antiversione acetabolare e l’estensione dell’anca. Nel secondo gruppo è stato evidenziato che l’aumento dell’antiversione femorale porta ad una rotazione interna dell’anca più pronunciata durante il cammino, ad una diminuzione dei bracci di leva abduttivi e ad un aumento delle forze di contatto. Il terzo gruppo di studio non ha riportato nessuna relazione tra antiversione femorale e acetabolare nei soggetti affetti da coxartrosi. D’altro canto, è possibile che la correlazione ricercata non sia stata trovata proprio perché il campione esaminato in questo studio presentava coxartrosi, elemento che potrebbe essere espressione di un non corretto adattamento tra anca e bacino. Conclusioni: la retroversione del bacino aumenta l’antiversione acetabolare e l’estensione dell’anca; l'aumento dell'antiversione del collo femorale è comunemente associato ad una maggiore rotazione interna dell'anca sia in stazione eretta che durante l'andatura, agendo come strategia compensativa per la diminuzione dei bracci di leva dei muscoli abduttori dell'anca. Non ci sono elementi per trarre conclusioni sulla relazione tra il grado di versione del bacino, l’antiversione del collo femorale e la mobilità dell’anca nel piano orizzontale e frontale.

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Esta videoaula (aula 2) apresenta o risco de viés nos estudos de tratamento.

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The present paper describes a novel, simple and reliable differential pulse voltammetric method for determining amitriptyline (AMT) in pharmaceutical formulations. It has been described for many authors that this antidepressant is electrochemically inactive at carbon electrodes. However, the procedure proposed herein consisted in electrochemically oxidizing AMT at an unmodified carbon nanotube paste electrode in the presence of 0.1 mol L(-1) sulfuric acid used as electrolyte. At such concentration, the acid facilitated the AMT electroxidation through one-electron transfer at 1.33 V vs. Ag/AgCl, as observed by the augmentation of peak current. Concerning optimized conditions (modulation time 5 ms, scan rate 90 mV s(-1), and pulse amplitude 120 mV) a linear calibration curve was constructed in the range of 0.0-30.0 μmol L(-1), with a correlation coefficient of 0.9991 and a limit of detection of 1.61 μmol L(-1). The procedure was successfully validated for intra- and inter-day precision and accuracy. Moreover, its feasibility was assessed through analysis of commercial pharmaceutical formulations and it has been compared to the UV-vis spectrophotometric method used as standard analytical technique recommended by the Brazilian Pharmacopoeia.

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Yellowing is an undesirable phenomenon that is common in people with white and grey hair. Because white hair has no melanin, the pigment responsible for hair colour, the effects of photodegradation are more visible in this type of hair. The origin of yellowing and its relation to photodegradation processes are not properly established, and many questions remain open in this field. In this work, the photodegradation of grey hair was investigated as a function of the wavelength of incident radiation, and its ultrastructure was determined, always comparing the results obtained for the white and black fibres present in grey hair with the results of white wool. The results presented herein indicate that the photobehaviour of grey hair irradiated with a mercury lamp or with solar radiation is dependent on the wavelength range of the incident radiation and on the initial shade of yellow in the sample. Two types of grey hair were used: (1) blended grey hair (more yellow) and (2) grey hair from a single-donor (less yellow). After exposure to a full-spectrum mercury lamp for 200 h, the blended white hair turned less yellow (the yellow-blue difference, Db(*) becomes negative, Db(*)=-6), whereas the white hair from the single-donor turned slightly yellower (Db(*)=2). In contrast, VIS+IR irradiation resulted in bleaching in both types of hair, whereas a thermal treatment (at 81 °C) caused yellowing of both types of hair, resulting in a Db(*)=3 for blended white hair and Db(*)=9 for single-donor hair. The identity of the yellow chromophores was investigated by UV-Vis spectroscopy. The results obtained with this technique were contradictory, however, and it was not possible to obtain a simple correlation between the sample shade of yellow and the absorption spectra. In addition, the results are discussed in terms of the morphology differences between the pigmented and non-pigmented parts of grey hair, the yellowing and bleaching effects of grey hair, and the occurrence of dark-follow reactions.

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Lawsonia inermis mediated synthesis of silver nanoparticles (Ag-NPs) and its efficacy against Candida albicans, Microsporum canis, Propioniabacterium acne and Trichophyton mentagrophytes is reported. A two-step mechanism has been proposed for bioreduction and formation of an intermediate complex leading to the synthesis of capped nanoparticles was developed. In addition, antimicrobial gel for M. canis and T. mentagrophytes was also formulated. Ag-NPs were synthesized by challenging the leaft extract of L. inermis with 1 mM AgNO₃. The Ag-NPs were characterized by Ultraviolet-Visible (UV-Vis) spectrophotometer and Fourier transform infrared spectroscopy (FTIR). Transmission electron microscopy (TEM), nanoparticle tracking and analysis sytem (NTA) and zeta potential was measured to detect the size of Ag-NPs. The antimicrobial activity of Ag-NPs was evaluated by disc diffusion method against the test organisms. Thus these Ag-NPs may prove as a better candidate drug due to their biogenic nature. Moreover, Ag-NPs may be an answer to the drug-resistant microorganisms.

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Retinal pigment epithelium cells, along with tight junction (TJ) proteins, constitute the outer blood retinal barrier (BRB). Contradictory findings suggest a role for the outer BRB in the pathogenesis of diabetic retinopathy (DR). The aim of this study was to investigate whether the mechanisms involved in these alterations are sensitive to nitrosative stress, and if cocoa or epicatechin (EC) protects from this damage under diabetic (DM) milieu conditions. Cells of a human RPE line (ARPE-19) were exposed to high-glucose (HG) conditions for 24 hours in the presence or absence of cocoa powder containing 0.5% or 60.5% polyphenol (low-polyphenol cocoa [LPC] and high-polyphenol cocoa [HPC], respectively). Exposure to HG decreased claudin-1 and occludin TJ expressions and increased extracellular matrix accumulation (ECM), whereas levels of TNF-α and inducible nitric oxide synthase (iNOS) were upregulated, accompanied by increased nitric oxide levels. This nitrosative stress resulted in S-nitrosylation of caveolin-1 (CAV-1), which in turn increased CAV-1 traffic and its interactions with claudin-1 and occludin. This cascade was inhibited by treatment with HPC or EC through δ-opioid receptor (DOR) binding and stimulation, thereby decreasing TNF-α-induced iNOS upregulation and CAV-1 endocytosis. The TJ functions were restored, leading to prevention of paracellular permeability, restoration of resistance of the ARPE-19 monolayer, and decreased ECM accumulation. The detrimental effects on TJs in ARPE-19 cells exposed to DM milieu occur through a CAV-1 S-nitrosylation-dependent endocytosis mechanism. High-polyphenol cocoa or EC exerts protective effects through DOR stimulation.

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TiO2 and TiO2/WO3 electrodes, irradiated by a solar simulator in configurations for heterogeneous photocatalysis (HP) and electrochemically-assisted HP (EHP), were used to remediate aqueous solutions containing 10 mg L(-1) (34 μmol L(-1)) of 17-α-ethinylestradiol (EE2), active component of most oral contraceptives. The photocatalysts consisted of 4.5 μm thick porous films of TiO2 and TiO2/WO3 (molar ratio W/Ti of 12%) deposited on transparent electrodes from aqueous suspensions of TiO2 particles and WO3 precursors, followed by thermal treatment at 450 (°)C. First, an energy diagram was organized with photoelectrochemical and UV-Vis absorption spectroscopy data and revealed that EE2 could be directly oxidized by the photogenerated holes at the semiconductor surfaces, considering the relative HOMO level for EE2 and the semiconductor valence band edges. Also, for the irradiated hybrid photocatalyst, electrons in TiO2 should be transferred to WO3 conduction band, while holes move toward TiO2 valence band, improving charge separation. The remediated EE2 solutions were analyzed by fluorescence, HPLC and total organic carbon measurements. As expected from the energy diagram, both photocatalysts promoted the EE2 oxidation in HP configuration; after 4 h, the EE2 concentration decayed to 6.2 mg L(-1) (35% of EE2 removal) with irradiated TiO2 while TiO2/WO3 electrode resulted in 45% EE2 removal. A higher performance was achieved in EHP systems, when a Pt wire was introduced as a counter-electrode and the photoelectrodes were biased at +0.7 V; then, the EE2 removal corresponded to 48 and 54% for the TiO2 and TiO2/WO3, respectively. The hybrid TiO2/WO3, when compared to TiO2 electrode, exhibited enhanced sunlight harvesting and improved separation of photogenerated charge carriers, resulting in higher performance for removing this contaminant of emerging concern from aqueous solution.

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New N-p-chloro-, N-p-bromo-, and N-p-nitrophenylazobenzylchitosan derivatives, as well as the corresponding azophenyl and azophenyl-p-sulfonic acids, were synthesized by coupling N-benzylvchitosan with aryl diazonium salts. The synthesized molecules were analyzed by UV-Vis, FT-IR, 1H-NMR and 15N-NMR spectroscopy. The capacity of copper chelation by these materials was studied by AAS. Chitosan and the derivatives were subjected to hydrolysis and the products were analyzed by ESI(+)-MS and GC-MS, confirming the formation of N-benzyl chitosan. Furthermore, the MS results indicate that a nucleophilic aromatic substitution (SnAr) reaction occurs under hydrolysis conditions, yielding chloroaniline from N-p-bromo-, and N-p-nitrophenylazo-benzylchitosan as well as bromoaniline from N-p-chloro-, and N-p-nitrophenylazobenzyl-chitosan.

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Silver nanoparticles have attracted considerable attention due to their beneficial properties. But toxicity issues associated with them are also rising. The reports in the past suggested health hazards of silver nanoparticles at the cellular, molecular, or whole organismal level in eukaryotes. Whereas, there is also need to examine the exposure effects of silver nanoparticle to the microbes, which are beneficial to humans as well as environment. The available literature suggests the harmful effects of physically and chemically synthesised silver nanoparticles. The toxicity of biogenically synthesized nanoparticles has been less studied than physically and chemically synthesised nanoparticles. Hence, there is a greater need to study the toxic effects of biologically synthesised silver nanoparticles in general and mycosynthesized nanoparticles in particular. In the present study, attempts have been made to assess the risk associated with the exposure of mycosynthesized silver nanoparticles on a beneficial soil microbe Pseudomonas putida. KT2440. The study demonstrates mycosynthesis of silver nanoparticles and their characterisation by UV-vis spectrophotometry, FTIR, X-ray diffraction, nanosight LM20 - a particle size distribution analyzer and TEM. Silver nanoparticles obtained herein were found to exert the hazardous effect at the concentration of 0.4μg/ml, which warrants further detailed investigations concerning toxicity.