297 resultados para Chemistry - History


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Skeletal muscle displays enormous plasticity to respond to contractile activity with muscle from strength- (ST) and endurance-trained (ET) athletes representing diverse states of the adaptation continuum. Training adaptation can be viewed as the accumulation of specific proteins. Hence, the altered gene expression that allows for changes in protein concentration is of major importance for any training adaptation. Accordingly, the aim of the present study was to quantify acute subcellular responses in muscle to habitual and unfamiliar exercise. After 24-h diet/exercise control, 13 male subjects (7 ST and 6 ET) performed a random order of either resistance (8 × 5 maximal leg extensions) or endurance exercise (1 h of cycling at 70% peak O2 uptake). Muscle biopsies were taken from vastus lateralis at rest and 3 h after exercise. Gene expression was analyzed using real-time PCR with changes normalized relative to preexercise values. After cycling exercise, peroxisome proliferator-activated receptor-γ coactivator-1α (ET ∼8.5-fold, ST ∼10-fold, P < 0.001), pyruvate dehydrogenase kinase-4 (PDK-4; ET ∼26-fold, ST ∼39-fold), vascular endothelial growth factor (VEGF; ET ∼4.5-fold, ST ∼4-fold), and muscle atrophy F-box protein (MAFbx) (ET ∼2-fold, ST ∼0.4-fold) mRNA increased in both groups, whereas MyoD (∼3-fold), myogenin (∼0.9-fold), and myostatin (∼2-fold) mRNA increased in ET but not in ST (P < 0.05). After resistance exercise PDK-4 (∼7-fold, P < 0.01) and MyoD (∼0.7-fold) increased, whereas MAFbx (∼0.7-fold) and myostatin (∼0.6-fold) decreased in ET but not in ST. We conclude that prior training history can modify the acute gene responses in skeletal muscle to subsequent exercise.

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This paper examines the most recent version of the Australian Curriculum: History F-10. It does so in two ways. First, it explores some of the strengths and weaknesses of this curriculum with reference to the decision to frame aspects of Australian history within the context of a world history approach. Whilst the positioning of Indigenous Histories is applauded, the curriculum’s lack of attention to the significance of the recent history of Australia’s Asian neighbours, and Australia’s relationship with them, is critiqued. This part of the paper also emphasises the need for comparative approaches and calls for greater emphasis on providing students with opportunities to critique and contest the construction of narratives about the past. Second, the paper introduces four invited articles that examine different aspects of the Australian Curriculum: History. Collectively these papers reiterate the significance of the richness of integrated and child-centred approaches and the importance of developing historical thinking, empathy and the historical imagination in the classroom.

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This paper explores an early modern application of the Stoic principle of similitudo temporum to the study of history. In so doing, it highlights the tension between historiography and antiquarianism, suggesting that the collection of remains – whether material or immaterial – was understood in at least some early modern circles as an integral part of the historiographic process. It also emphasises the evolving meaning of “history” during this time, drawing attention to the perceived novelty of such antiquarian approaches to the study of the past, and briefly exploring subtle differences between the example at hand and the work and activities of better-known figures such as Nicolas-Claude Fabri de Peiresc and Justus Lipsius. As such, this paper makes a contribution to our evolving understanding of early modern scholarship, and draws attention to the variegated approaches of its practitioners to contemporary issues.

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Poly(styrene)-block-poly(ethylene oxide) copolymers synthesized via the combination of reversible addition fragmentation chain transfer (RAFT) polymerization and hetero Diels–Alder (HDA) cycloaddition can be cleaved in the solid state by a retro-HDA reaction occurring at 90 °C. Nanoporous films can be prepared from these polymers using a simple heating and washing procedure.

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This study explores the development of a coding system for analysing test questions in two context-based chemistry exams. We describe our unique analytical procedures before contrasting the data from both tests. Our findings indicate that when a new curriculum is developed such as a context-based curriculum, teachers are required to combine the previously separate domains of context and concept to develop contextualised assessment. We argue that constructing contextualised assessment items requires teachers to view concepts and context as interconnected rather than as separate entities that may polarise scientific endeavour. Implications for practice, curriculum and assessment-development in context-based courses are proposed.

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This study investigated whether conceptual development is greater if students learning senior chemistry hear teacher explanations and other traditional teaching approaches first then see computer based visualizations or vice versa. Five Canadian chemistry classes, taught by three different teachers, studied the topics of Le Chatelier’s Principle and dynamic chemical equilibria using scientific visualizations with the explanation and visualizations in different orders. Conceptual development was measured using a 12 item test based on the Chemistry Concepts Inventory. Data was obtained about the students’ abilities, learning styles (auditory, visual or kinesthetic) and sex, and the relationships between these factors and conceptual development due to the teaching sequences were investigated. It was found that teaching sequence is not important in terms of students’ conceptual learning gains, across the whole cohort or for any of the three subgroups.

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In this reflection on research processes a humanities researcher begins to ask questions about the cultural materialist dimensions of research activities. At the center of this exploration are questions relating to the ways in which personal histories and experiences inform particular research processes and the ways in which a researcher's habits of collecting and working with data are regulated by cultural and social practice. The reflection on personal research processes is located in terms of the ethics work of Michel Foucault that provides reminders about the role of modern bureaucracy in governing what appear to be personal processes.

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Scientific visualisations such as computer-based animations and simulations are increasingly a feature of high school science instruction. Visualisations are adopted enthusiastically by teachers and embraced by students, and there is good evidence that they are popular and well received. There is limited evidence, however, of how effective they are in enabling students to learn key scientific concepts. This paper reports the results of a quantitative study conducted in Australian physics and chemistry classrooms. In general there was no statistically significant difference between teaching with and without visualisations, however there were intriguing differences around student sex and academic ability.

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Visual modes of representation have always been very important in science and science education. Interactive computer-based animations and simulations offer new visual resources for chemistry education. Many studies have shown that students enjoy learning with visualisations but few have explored how learning outcomes compare when teaching with or without visualisations. This study employs a quasi-experimental crossover research design and quantitative methods to measure the educational effectiveness - defined as level of conceptual development on the part of students - of using computer-based scientific visualisations versus teaching without visualisations in teaching chemistry. In addition to finding that teaching with visualisations offered outcomes that were not significantly different from teaching without visualisations, the study also explored differences in outcomes for male and female students, students with different learning styles (visual, aural, kinesthetic) and students of differing levels of academic ability.

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Enormous amounts of money and energy are being devoted to the development, use and organisation of computer-based scientific visualisations (e.g. animations and simulations) in science education. It seems plausible that visualisations that enable students to gain visual access to scientific phenomena that are too large, too small or occur too quickly or too slowly to be seen by the naked eye, or to scientific concepts and models, would yield enhanced conceptual learning. When the literature is searched, however, it quickly becomes apparent that there is a dearth of quantitative evidence for the effectiveness of scientific visualisations in enhancing students’ learning of science concepts. This paper outlines an Australian project that is using innovative research methodology to gather evidence on this question in physics and chemistry classrooms.

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The Australian Curriculum marks national reforms in social science education, first with the return to the disciplines of history and geography and second, through a new approach to interdisciplinary learning. This paper raises the question of whether the promise of interdisciplinary learning can be realised in the middle years of schooling if teachers have to teach history as a discipline rather than within an over-arching integrated curriculum framework. The paper explores the national blueprints and considers the national history curriculum in light of theories of teachers’ knowledge and middle school education. Evidence from teacher interviews indicates that historical understanding can be achieved through integrated frameworks to meet the goals of middle schooling.

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- briefly describe the importance of public health history to contemporary public health - briefly describe the ancient history of public health - outline the key periods and activities in the modern history of Western public health - describe and understand the important roles of political, social, environmental and economic factors as they impact on health - consider the major factors that have influenced an understanding of contemporary public health in the past 40 years.