Práticas de literacia familiar em benguela (angola): Um estudo exploratório.

As investigações mostram que a aprendizagem da linguagem escrita começa muito antes do ensino formal e que as práticas e o ambiente de literacia familiar influenciam a literacia emergente e o desenvolvimento da linguagem escrita. Mas, se estes estudos são desenvolvidos no Ocidente, em África pouco se tem feito e em Angola não se conhece nenhum estudo. Com base nos estudos existentes, em diversos contextos culturais, verifica-se que a literacia familiar existe, podendo as práticas variar no tipo e frequência uma vez que o que se passa num contexto, pode não ser igual ao que se passa noutra realidade cultural diferente. Neste sentido este trabalho, procura caraterizar as práticas e o ambiente familiar de literacia em 11 famílias de Benguela com um filho a frequentar o início da escolaridade. Os dados foram recolhidos através de uma entrevista informal aos pais. Os resultados mostram que as práticas de literacia familiar são essencialmente práticas formais, muito ligadas à escola e às tarefas escolares. No mesmo sentido verificámos que a responsabilidade pela aprendizagem da linguagem escrita é atribuída à escola, e a explicadores. Apesar de surgirem algumas referências do uso da literacia associado a práticas religiosas, poucas referências foram feitas a práticas informais ou lúdicas. Foi clara a quase inexistência de materiais de leitura (jornais, livros, revistas) para além dos escolares. A falta de tempo, a escassez de bibliotecas públicas e livrarias, a falta dos recursos financeiras para aquisição do material de literacia e a iliteracia foram apontados como obstáculos para o desenvolvimento de outro tipo de práticasinfo:eu-repo/semantics/publishedVersio

Hierarchical Core–Shell Al₂O₃@Pd-CoAlO Microspheres for Low-Temperature Toluene Combustion

The high-efficiency catalyst is the key factor of volatile organic compounds (VOCs) catalytic combustion. Herein, hierarchical core–shell Al₂O₃@Pd-CoAlO (Pd-CoAlO-Al) microspheres have been successfully prepared and used for toluene combustion. The experimental results reveal that the core–shell Pd-CoAlO-Al exhibits outstanding catalytic efficiency due to the homogeneous distribution of Pd-CoAlO nanosheets on Al₂O₃ supports and the strong interaction between the catalytically active Pd-CoAlO nanosheets and the Al₂O₃ supports. In particular, the catalytically active PdO contributes to the excellent catalytic efficiency. In addition, the <i>in situ</i> DRIFTS results indicate that the benzoate species are the main intermediate species in toluene combustion

Heterogeneous Reactions between Toluene and NO₂ on Mineral Particles under Simulated Atmospheric Conditions

Heterogeneous reactions between organic and inorganic gases with aerosols are important for the study of smog occurrence and development. In this study, heterogeneous reactions between toluene and NO₂ with three atmospheric mineral particles in the presence or absence of UV light were investigated. The three mineral particles were SiO₂, α-Fe₂O₃, and BS (butlerite and szmolnokite). In a dark environment, benzaldehyde was produced on α-Fe₂O₃. For BS, nitrotoluene and benzaldehyde were obtained. No aromatic products were produced in the absence of NO₂ in the system. In the presence of UV irradiation, benzaldehyde was detected on the SiO₂ surface. Identical products were produced in the presence and absence of UV light over α-Fe₂O₃ and BS. UV light promoted nitrite to nitrate on mineral particles surface. On the basisi of the X-ray photoelectron spectroscopy (XPS) results, a portion of BS was reduced from Fe³⁺ to Fe²⁺ with the adsorption of toluene or the reaction with toluene and NO₂. Sulfate may play a key role in the generation of nitrotoluene on BS particles. From this research, the heterogeneous reactions between organic and inorganic gases with aerosols that occur during smog events will be better understood

Extraordinary Deactivation Offset Effect of Arsenic and Calcium on CeO₂–WO₃ SCR Catalysts

An extraordinary deactivation offset effect of calcium and arsenic on CeO₂–WO₃ catalyst had been found for selective catalytic reduction of NO with NH₃ (NH₃–SCR). It was discovered that the maximum NO_<i>x</i> conversion of As–Ca poisoned catalyst reached up to 89% at 350 °C with the gaseous hourly space velocity of 120 000 mL·(g·h)⁻¹. The offset effect mechanisms were explored with respect to the changes of catalyst structure, surface acidity, redox property and reaction route by XRD, XPS, H₂-TPR, O₂-TPD, NH₃-TPD and in situ Raman, in situ TG, and DRIFTS. The results manifested that Lewis acid sites and reducibility originating from CeO₂ were obviously recovered, because the strong interaction between cerium and arsenic was weakened when Ca and As coexisted. Meanwhile, the CaWO₄ phase generated on Ca poisoned catalyst almost disappeared after As doping together, which made for Brønsted acid sites reformation on catalyst surface. Furthermore, surface Ce⁴⁺ proportion and oxygen defect sites amount were also restored for two-component poisoned catalyst, which favored NH₃ activation and further reaction. Finally, the reasons for the gap of catalytic performance between fresh and As–Ca poisoned catalyst were also proposed as follows: (1) surface area decrease; (2) crystalline WO₃ particles generation; and (3) oxygen defect sites irreversible loss

Comparison of the Structures and Mechanism of Arsenic Deactivation of CeO₂–MoO₃ and CeO₂–WO₃ SCR Catalysts

The mechanism of arsenic poisoning of CeO₂–WO₃ (CW) and CeO₂–MoO₃ (CM) catalysts during the selective catalytic reduction (SCR) of NO_<i>x</i> with NH₃ was investigated. It was found that the ratio of activity loss of the CW catalyst decreases as the temperature increases, while the opposite tendency was observed for the CM catalyst. The fresh and poisoned catalysts were characterized using X-ray diffraction (XRD) temperature-programmed reduction with H₂ (H₂-TPR), X-ray photoelectron spectra (XPS), NH₃-temperature-programmed desorption (NH₃-TPD), in situ DRIFTS, and in situ Raman spectroscopy. The results indicate that arsenic oxide primarily destroys the structure of the surface CeOx species in the CM catalyst but prefers to interact with WO₃ in the CW catalyst. Additionally, the BET surface area, the number and stability of Lewis acid sites, and the NO_<i>x</i> adsorption for these two types of catalysts clearly decrease after deactivation. According to the DRIFTS and Raman investigations, at low temperatures, the greater number of sites with adsorbed NH₃ in the poisoned CM catalyst leads to less loss of activity than the poisoned CW catalyst. However, at high temperatures, the greater number of Lewis acid sites remaining in the poisoned CW catalyst may play an important role in maintaining the activity of this catalyst

Pt Nanoparticles Embedded in Colloidal Crystal Template Derived 3D Ordered Macroporous Ce_0.6Zr_0.3Y_0.1O₂: Highly Efficient Catalysts for Methane Combustion

Three-dimensionally ordered macro/mesoporous Ce_0.6Zr_0.3Y_0.1O₂ (3DOM CZY) supported high-dispersion Pt nanoparticles (<i>x</i> wt % Pt/3DOM CZY, <i>x</i> = 0.6, 1.1, and 1.7) were successfully synthesized via the cetyltrimethylammonium bromide/triblock copolymer P123 assisted gas bubbling reduction route. The 3DOM CZY and <i>x</i> wt % Pt/3DOM CZY samples exhibited a high surface area of 84–94 m²/g. Pt nanoparticles (NPs) with a size of 2.6–4.2 nm were uniformly dispersed on the surface of 3DOM CZY. The 1.1 wt % Pt/3DOM CZY sample showed excellent catalytic performance, giving a <i>T</i>_90% value at 598 °C at gas hourly space velocity (GHSV) of 30000 mL/(g h) and the highest turnover frequency (TOF_Pt) of 6.98 × 10^–3 mol/(mol_Pt s) at 400 °C for methane combustion. The apparent activation energy (64 kJ/mol) over 1.1 wt % Pt/3DOM CZY was much lower than that (95 kJ/mol) over Bulk CZY. The effects of water vapor and SO₂ on the catalytic activity of 1.1 wt % Pt/3DOM CZY were also examined. It is concluded that the excellent catalytic activity of 1.1 wt % Pt/3DOM CZY was associated with its high oxygen adspecies concentration, good low-temperature reducibility, and strong interaction between Pt NPs and CZY as well as large surface area and unique nanovoid-walled 3DOM structure

Additional file 1: of Association of Interleukin-1 gene clusters polymorphisms with primary open-angle glaucoma: a meta-analysis

The full details of databases searching terms. (DOCX 36 kb)s (DOCX 36 kb

Novel Mn–Ce–Ti Mixed-Oxide Catalyst for the Selective Catalytic Reduction of NO_<i>x</i> with NH₃

Mn–Ce–Ti mixed-oxide catalyst prepared by the hydrothermal method was investigated for the selective catalytic reduction (SCR) of NO_<i>x</i> with NH₃ in the presence of oxygen. It was found that the environmentally benign Mn–Ce–Ti catalyst exhibited excellent NH₃-SCR activity and strong resistance against H₂O and SO₂ with a broad operation temperature window, which is very competitive for the practical application in controlling the NO_<i>x</i> emission from diesel engines. On the basis of the catalyst characterization, the dual redox cycles (Mn⁴⁺ + Ce³⁺ ↔ Mn³⁺ + Ce⁴⁺, Mn⁴⁺ + Ti³⁺ ↔ Mn³⁺ + Ti⁴⁺) and the amorphous structure play key roles for the high catalytic deNO_<i>x</i> performance. Diffuse reflectance infrared Fourier transform spectroscopy studies showed that the synergetic effect between Mn and Ce contributes to the formation of reactive intermediate species, thus promoting the NH₃-SCR to proceed

Design Strategies for Development of SCR Catalyst: Improvement of Alkali Poisoning Resistance and Novel Regeneration Method

Based on the ideas of the additives modification and regeneration method update, two different strategies were designed to deal with the traditional SCR catalyst poisoned by alkali metals. First, ceria doping on the V₂O₅–WO₃/TiO₂ catalyst could promote the SCR performance even reducing the V loading, which resulted in the enhancement of the catalyst’s alkali poisoning resistance. Then, a novel method, electrophoresis treatment, was employed to regenerate the alkali poisoned V₂O₅–WO₃/TiO₂ catalyst. This novel technique could dramatically enhance the SCR activities of the alkali poisoned catalysts by removing approximately 95% K or Na ions from the catalyst and showed less hazardous to the environment. Finally, the deactivation mechanisms by the alkali metals were extensively studied by employing both the experimental and DFT theoretical approaches. Alkali atom mainly influences the active site V species rather than W oxides. The decrease of catalyst surface acidity might directly reduce the catalytic activity, while the reducibility of catalysts could be another important factor

Additional file 4: Table S2. of Association of Interleukin-1 gene clusters polymorphisms with primary open-angle glaucoma: a meta-analysis

Quality of included studies. (DOC 68 kb) (DOC 68 kb