179 research outputs found

    The prospective kindergarten and elementary school teachers’ understanding of the ratio concept

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    Este artigo centra-se na compreensão que futuros educadores e professores dos primeiros anos de escolaridade evidenciam do conceito de razão. No estudo participaram 81 estudantes do 2º ano da Licenciatura em Educação Básica, de uma universidade portuguesa, aos quais foi aplicado um questionário, incidindo em quatro dimensões: significado de razão; usos do conceito de razão; representação simbólica de razão; e representações para explicação do conceito de razão. Em termos de resultados, as maiores frequências foram obtidas para a: ideia de razão como comparação/relação entre grandezas; crença em que o conceito de razão pode ser usado em contextos diversificados; crença em que pode ser representado através de operações envolvendo letras, números ou apenas os sinais das operações, quando é pedida a sua representação simbólica, e através de diagramas e representações gráficas, quando é solicitada a descrição da sua explicação. Estes resultados revelam fragilidades no conhecimento matemático dos estudantes, sobretudo no que se refere à definição do conceito de razão e às suas representações.This paper focuses on the prospective kindergarten and elementary school teachers’ understanding of the ratio concept. Eighty-one undergraduates preparing to become kindergarten and primary school teachers, in a Portuguese university, participated in the study. They answered to a questionnaire aiming at evaluating their understanding of the ratio concept based on four dimensions: meaning of ratio; use of the ratio concept; symbolic representations of ratio; and representations for explaining the ratio concept. As far as results are concerned, the highest frequencies were obtained for: the idea of ratio as a comparison/relationship between two magnitudes; the belief that this concept is used in several contexts; the belief that it can be represented through operations with letters, figures or operation signals, as in symbolic representations; and through diagrams and graphical representations, as in representations for explaining the ratio concept. The results show weaknesses in prospective teachers’ mathematical knowledge of ratio, namely with regard to its definition and representations.Este trabalho contou com o apoio de Fundos Nacionais através da FCT – Fundação para a Ciência e a Tecnologia no âmbito do projecto PEst-OE/CED/UI1661/2014 do CIEd-UM.info:eu-repo/semantics/publishedVersio

    The impact of curriculum hierarchies on the development of professional self in teaching: student-teachers of drama negotiating issues of subject status at the interface between drama and English

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    At the level of policy the relative ‘value’ of subjects is determined by their official curriculum designation, creating a hierarchy of learning within which particular subjects are categorised as optional to the educational experience of young people. This situation is well-illustrated by the marginalised position of drama in the National Curriculum for England and Wales in which drama appears as an adjunct to the ‘core’ subject English. Yet at school level drama has survived as a discrete and reasonably embedded subject. Drawing on questionnaire and interview data, I investigate the effects of this mismatch on the emergence of pedagogical content knowledge, linked to notions of professional self, in drama student-teachers at one university in the UK. Findings indicate that the student-teachers, whilst not entirely eschewing a less-regulated relationship between the two subjects, view the curriculum for English and its accompanying assessment regime as an inadequate host for drama. In addition, they regard teacher autonomy over curriculum content and pedagogy as indicative of a high degree of professional expertise. This suggests that a case can be made for re-evaluating the nature of the relationship between drama and English and its representation in policy-constructed curricula

    Accommodating to English-medium instruction in teacher education in Finland

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    This study analyses teacher educators’ and student teachers’ perceptions of teaching and learning situations in an international English as a lingua franca (ELF) context in an English-medium instruction (EMI) teacher education programme in Finland. The analysis of semi-structured interviews revealed that the participants perceived a partial reversal of traditional teacher and student roles; students assisted voluntarily and teaching became reciprocal. Some teachers reflected on having used typical strategies in ELF context such as code-switching to further communication and engage students. However, teachers’ lack of fluency was sometimes considered causing frustration among students and affected negatively their feeling of being professional teacher educators. Nevertheless, by increasing more learner-led activities, ELF can positively affect teacher education pedagogy.Peer reviewe

    Olives and olive oil are sources of electrophilic fatty acid nitroalkenes

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    Extra virgin olive oil (EVOO) and olives, key sources of unsaturated fatty acids in the Mediterranean diet, provide health benefits to humans. Nitric oxide (•NO) and nitrite (NO2-)-dependent reactions of unsaturated fatty acids yield electrophilic nitroalkene derivatives (NO 2-FA) that manifest salutary pleiotropic cell signaling responses in mammals. Herein, the endogenous presence of NO2-FA in both EVOO and fresh olives was demonstrated by mass spectrometry. The electrophilic nature of these species was affirmed by the detection of significant levels of protein cysteine adducts of nitro-oleic acid (NO2-OA-cysteine) in fresh olives, especially in the peel. Further nitration of EVOO by NO2- under acidic gastric digestive conditions revealed that human consumption of olive lipids will produce additional nitro-conjugated linoleic acid (NO2-cLA) and nitro-oleic acid (NO2-OA). The presence of free and protein-adducted NO2-FA in both mammalian and plant lipids further affirm a role for these species as signaling mediators. Since NO2-FA instigate adaptive anti-inflammatory gene expression and metabolic responses, these redox-derived metabolites may contribute to the cardiovascular benefits associated with the Mediterranean diet. © 2014 Fazzari et al

    RNAi screen for NRF2 inducers identifies targets that rescue primary lung epithelial cells from cigarette smoke induced radical stress

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    Chronic Obstructive Pulmonary Disease (COPD) is a highly prevalent condition characterized by inflammation and progressive obstruction of the airways. At present, there is no treatment that suppresses the chronic inflammation of the disease, and COPD patients often succumb to the condition. Excessive oxidative stress caused by smoke inhalation is a major driving force of the disease. The transcription factor NRF2 is a critical player in the battle against oxidative stress and its function is impaired in COPD. Increasing NRF2 activity may therefore be a viable therapeutic option for COPD treatment. We show that down regulation of KEAP1, a NRF2 inhibitor, protects primary human lung epithelial cells from cigarette-smoke-extract (CSE) induced cell death in an established in vitro model of radical stress. To identify new potential drug targets with a similar effect, we performed a siRNA screen of the 'druggable' genome using a NRF2 transcriptional reporter cell line. This screen identified multiple genes that when down regulated increased NRF2 transcriptional activity and provided a survival benefit in the in vitro model. Our results suggest that inhibiting components of the ubiquitin-proteasome system will have the strongest effects on NRF2 transcriptional activity by increasing NRF2 levels. We also find that down regulation of the small GTPase Rab28 or the Estrogen Receptor ESRRA provide a survival benefit. Rab28 knockdown increased NRF2 protein levels, indicating that Rab28 may regulate NRF2 proteolysis. Conversely ESRRA down regulation increased NRF2 transcriptional activity without affecting NRF2 levels, suggesting a proteasome-independent mechanism

    The importance of sedimenting organic matter, relative to oxygen and temperature, in structuring lake profundal macroinvertebrate assemblages

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    We quantified the role of a main food resource, sedimenting organic matter (SOM), relative to oxygen (DO) and temperature (TEMP) in structuring profundal macroinvertebrate assemblages in boreal lakes. SOM from 26 basins of 11 Finnish lakes was analysed for quantity (sedimentation rates), quality (C:N:P stoichiometry) and origin (carbon stable isotopes, d13C). Hypolimnetic oxygen and temperature were measured from each site during summer stratification. Partial canonical correspondence analysis (CCA) and partial regression analyses were used to quantify contributions of SOM, DO and TEMP to community composition and three macroinvertebrate metrics. The results suggested a major contribution of SOM in regulating the community composition and total biomass. Oxygen best explained the Shannon diversity, whereas TEMP had largest contribution to the variation of Benthic Quality Index. Community composition was most strongly related to d13C of SOM. Based on additional d13C and stoichiometric analyses of chironomid taxa, marked differences were apparent in their utilization of SOM and body stoichiometry; taxa characteristic of oligotrophic conditions exhibited higher C:N ratios and lower C:P and N:P ratios compared to the species typical of eutrophic lakes. The results highlight the role of SOM in regulating benthic communities and the distributions of individual species, particularly in oligotrophic systems
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