396 research outputs found
Public interactive displays in schools : involving teachers in the design and assessment of innovative technologies.
The introduction of an innovative technology in schools has the potential to change the education system, bringing major changes in the way teachers work, students learn challenging the way schools are managed. Informed by literature that sustains integration of technological innovations in educational contexts is influenced by instrumental factors such as school leadership and organizational structure (Dix, 2007) and using a development research approach, three hands-on workshops were conducted with a criterion sample of teachers of a secondary school from the north of Portugal in order to elicit expectations towards the use of digital displays to viewing videos, explore possible features for the system design as well as the management of the technological device in the school system. Development research methodology showed to produce usable findings that were born out of the collaborative partnership between researchers and stakeholders focused around inquiry that is of interest to educational leaders and teachers with the intention to inform and transform pedagogical practices. In sum, the development research approach allowed, for one hand, the conception of a new tool pedagogically adjusted to students learning needs as well as to the school organizational rules and structures. On the other hand, our methodological approach aimed to foster the acceptance of the tool as a useful pedagogical instrument for other teachers and for the whole school ecology.Comissão Europeia (FP7)CIEC - Centro de Investigação em Estudos da Criança, UM (UI 317 da FCT
Nitric oxide and nitrous oxide emissions from cattle-slurry and mineral fertiliser treated with nitrification inhibitor to an agricultural soil: a laboratory approach
Research ArticleThe application of organic and mineral fertilisers to soil can result in increased gaseous emissions to the atmosphere such as
nitric oxide (NO) and nitrous oxide (N2O) gases. The aim of this study was to evaluate under laboratory conditions the effects on
mineral N dynamics and NO and N2O emissions of application to soil of cattle slurry derived liquid fraction (LF) obtained by screw
press and mineral fertiliser (MF), both treated with or without the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP).
An aerobic laboratory incubation was performed over 93 days with a Dystric Cambisol amended with mechanically separated LF
or mineral fertiliser ammonium sulphate only or combined with DMPP. Two additional treatments were included: soil only and soil
amended with DMPP. Nitrogen immobilisation was the dominant process with MF amendment, whereas N mineralisation has been
observed with LF. The application of LF reduced significantly NO emissions by 80% relative to mineral but no differences were
observed with N2O emissions. The addition of DMPP to MF induced a decrease of 18 and 29% in NO and N2O emissions whereas
DMPP combined with LF reduced (numerically but not statistically) these emissions in 20 and 10%, respectively. Results obtained
in our study suggest that N (NO + N2O) losses can be mitigated by adding DMPP to mineral fertilisers or replacing mineral fertiliser
by LFinfo:eu-repo/semantics/publishedVersio
Tools for educational content preparation and delivery
Supplemental information by the authors of the article "Problems and prospects of hybrid learning in Higher Education"N/
Organic Lettuce Growth And Nutrient Uptake Response To Lime, Compost And Rock Phosphate
Fertilizer recommendations are needed to increase organic vegetable yields. Thus, organic lettuce growth and nutrient uptake was investigated in a randomized block pot experiment with twelve treatments from the factorial structure of three factors: (i) Gafsa phosphate [0 and 200 kg phosphorus pentoxide (P 2 O 5 ) ha -1 ], (ii) compost from source separated municipal organic waste (0, 15, and 30 t ha -1 ) and (iii) limestone [0 and 8 t ha -1 calcium carbonate (CaCO 3 ) equivalent]. Lettuce yield increased with compost application and a first order interaction between lime and phosphate was clear because lime partially replaced the need for phosphate. This was explained by the effect of liming on P availability in acid soils. Nitrogen (N), phosphorus (P), and potassium (K) accumulation increased in lettuces produced with compost or phosphate but only the accumulation of N was increased with lime. This compost is recommended to increase nutrient availability for organic lettuce whereas the need for phosphate fertilization may decrease with liming.info:eu-repo/semantics/publishedVersio
Carbon and nitrogen mineralisation from green manures as alternative nitrogen sources in Mediterranean farming
The soil incorporation of green manures is a practice that can be used in sustainable agriculture and in organic farming, where nitrogen (N) sources are limited. The aim of this study was to evaluate balansa clover (Trifolium michelianum Savi), yellow lupine (Lupinus luteus L.) and ryegrass (Lolium multiflorum Lam.) as potential alternative N sources. A total of nine treatments were considered in this study: control, aerial of balansa clover, roots of balansa clover, aerial of yellow lupine, roots of yellow lupine, aerial of ryegrass, roots of ryegrass, mixture aerial + roots of yellow lupine and mixture aerial + roots of ryegrass. A laboratory incubation experiment was conducted under controlled conditions during 196 days and carbon and N mineralisation were followed. Results showed that green manures are appropriate N sources for Mediterranean farming. No significant differences in terms of N mineralisation were observed between aerial or roots biomass of the green manures. Besides, 37–55% of total N applied was mineralised in treatments amended with balansa clover or yellow lupine, whereas 13–21% of total N applied was mineralised in ryegrass. It can be concluded that the most efficient green manure for supplying mineral N to the succeeding crop was yellow lupine.info:eu-repo/semantics/publishedVersio
Práticas educativas com a edição de vídeo: Motivar com criatividade
Os alunos que estudam temas nas áreas CTEM (Ciências, Tecnologia, Engenharia e Matemática) encontram muitas vezes barreiras à compreensão de alguns conceitos complexos considerados essenciais que têm pouca motivação para superar (Adams, et al., 2013).
Integrado num projeto de investigação que tem como objetivo promover a curiosidade dos alunos nas áreas CTEM através da edição criativa de vídeo, este artigo apresenta um estudo piloto que contribui para a compreensão de como a edição de vídeo por parte dos alunos pode ser integrada no currículo para motivar com criatividade e desenvolver práticas que melhorem a aprendizagem.
Assim, foi organizado uma atividade de sala de aula com alunos do 12o ano de escolaridade de um curso de Artes, que envolveu a escolha de conceitos complexos pelos alunos para serem explicados através de vídeos. 18 alunos, organizados em pares, desenvolveram o storyboard colaborativamente. Os conceitos foram validados por professores das áreas disciplinares dos temas abordados. Posteriormente, e de forma autónoma, os alunos filmaram e editaram os vídeos, que foram partilhados no ecrã público da escola para gerar curiosidade e cenários de aprendizagem.
Os resultados sugerem que os (i) alunos são criativos, (ii) trabalham bem colaborativamente e (iii) estão recetivos ao desafio de criarem vídeos explicativos para gerar cenários de aprendizagem sobre assuntos escolares. Concluímos ainda que os (iv) alunos são determinados e automotivados para atividades escolares que envolvam meios tecnológicos.
As informações recolhidas neste estudo piloto serviram para refinar a metodologia de pesquisa para um estudo e desenvolver em grande escala.Comissão Europeia (FP7)CIEC - Centro de Investigação em Estudos da Criança, UM (UI 317 da FCT
A 3-year field study to assess winter cover crops as nitrogen sources for an organic maize crop in Mediterranean Portugal
Current environmental concerns, the rising economic and environmental costs of mineral fertilizers and the need
to respond to the limitations of N fertilization in organic farming motivate the search for alternative sources of N
in maize cropping. Forage legumes used as winter cover crops may improve soil N fertility and offer benefits to
the environment. The aim of this study was to examine the effects, in a factorial field experiment, of two sowing
dates (SD) and nine different cover crop treatments (balansa clover, crimson clover, gland clover, arrowleaf
clover, French serradella, yellow lupin, Italian ryegrass, a cover mixture and a weedy fallow) as a potential
alternative N source in an organically managed maize crop. The experiment was conducted at Viseu (Portugal)
for three years (2007/2008, 2008/2009 and 2011/12), in the same field. Results showed that maize grain yield
was not influenced by cover crop species but was affected by SD and the higher dry matter (DM) aboveground
biomass production was observed in early SD (6.1 t ha 1). The cover crops revealed their importance in maize N
uptake: yellow lupin of earlier SD had the highest N uptake (83.6 kg N ha 1), but this was not significantly
different from balansa clover (83.2 kg N ha 1). Ryegrass was the most efficient in depleting soil mineral N but
values were just significantly lower than yellow lupin.
Lupin was the least efficient, leaving more mineral N in the soil than the others cover crops, immediately
before the period when the risk of leaching is high. It was concluded that, under the edaphoclimatic conditions
tested, most of the tested cover crops were efficient in supplying N to maize, and balansa clover had the best
performance.info:eu-repo/semantics/publishedVersio
Assessment of Mineralized Nitrogen During Maize Growth Succeeding Different Winter Cover Crops in the Mediterranean Environment
Background:
Understanding soil nitrogen (N) dynamics is essential to find alternative N sources and improve N use efficiency in agriculture.
Objective:
The aim of this study was to assess N mineralization rates from residues of winter cover crops, during maize crop season, under Mediterranean conditions.
Methods:
A field experiment was carried out from May to September in central Portugal, with four replications, two sowing dates of cover crops (15/10/2011 and 29/11/2011) and three cover crops residues (balansa clover, ryegrass and yellow lupine) that were incorporated in the soil. Plots were cropped with local maize and net N mineralization was measured during the crop cycle, using soil cylinders placed inside micro-perforated polyethylene bags.
Results and Discussion:
Early sowing of the cover crops residues increased the NH4+ and NO3- contents in the soil. Yellow lupine residue had the highest rate of daily N mineralization (0.71 mg N kg-1 day-1). For all treatments, the highest mineralization rate was found in the last incubation period, ranging between 0.78 mg N kg-1 day-1 and 1.84 mg N kg-1 day-1, both for balansa clover, from the second and the first sowing date, respectively.
Conclusion:
The present study suggests that, under Mediterranean field conditions, cover crops residue of Italian ryegrass, balansa clover and yellow lupin can be used as a nitrogen source namely for sustainable maize crops.info:eu-repo/semantics/publishedVersio
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