217 research outputs found

    Observation of magnetism in Au thin films

    Full text link
    Direct magnetization measurements of thin gold films are presented. These measurements integrate the signal from the thin film under study and the magnetic contribution of the film's interface with the substrate. The diamagnetic contribution to the signal from the bulk substrate is of the same order as the noise level. we find that thin gold films can exhibit positive magnetization. The character of their magnetic behavior is strongly substrate dependent.Comment: 9 pages, 4 figure

    The District Effect: Systemic Responses to High Stakes Accountability Policies in Six Southern States

    Get PDF
    High stakes accountability (HSA) reforms were enacted in state after state and federally through the No Child Left Behind law, based on the belief that incentives that have consequences attached are effective ways to motivate educators to improve student performance. Our focus for this article is on school district level responses to HSA reforms that could produce positive changes in teaching and learning. We set out to determine whether a district effect was present in the implementation of HSA systems in six southern states and whether that effect was accompanied by the types of activities previously identified in the research literature as being associated with changes in teaching and learning and student achievement. We tested a theory of action that assumed that HSA would cause school districts to develop coherent instructional strategies that would be evidenced by the provision of coherent, high-quality professional development and the alignment of district policy and resources in support of school improvement. These activities on the part of districts would then improve student achievement as measured by state tests

    NMR Time Reversal Experiments in Highly Polarised Liquid 3He-4He Mixtures

    Full text link
    Long-range magnetic interactions in highly magnetised liquids (laser-polarised 3He-4He dilute mixtures at 1 K in our experiment) introduce a significant non-linear and non-local contribution to the evolution of nuclear magnetisation that leads to instabilities during free precession. We recently demonstrated that a multi-echo NMR sequence, based on the magic sandwich pulse scheme developed for solid-state NMR, can be used to stabilise the magnetisation against the effect of distant dipolar fields. Here, we report investigations of echo attenuation in an applied field gradient that show the potential of this NMR sequence for spin diffusion measurements at high magnetisation densities.Comment: Accepted for publication in the Journal of Low Temperature Physic

    Linear Spatial–Numeric Associations Aid Memory for Single Numbers

    Get PDF
    Memory for numbers improves with age. One source of this improvement may be learning linear spatial–numeric associations, but previous evidence for this hypothesis likely confounded memory span with quality of numerical magnitude representations and failed to distinguish spatial–numeric mappings from other numeric abilities, such as counting or number word-cardinality mapping. To obviate the influence of memory span on numerical memory, we examined 39 3- to 5-year-olds’ ability to recall one spontaneously produced number (1–20) after a delay, and the relation between numeric recall (controlling for non-numeric recall) and quality of mapping between symbolic and non-symbolic quantities using number-line estimation, give-a-number estimation, and counting tasks. Consistent with previous reports, mapping of numerals to space, to discrete quantities, and to numbers in memory displayed a logarithmic-to-linear shift. Also, linearity of spatial–numeric mapping correlated strongly with multiple measures of numeric recall (percent correct and percent absolute error), even when controlling for age and non-numeric memory. Results suggest that linear spatial–numeric mappings may aid memory for number over and above children’s other numeric skills

    Empirical evidence of the impact of lesson study on: students’ achievement, teachers’ professional learning and on institutional and system evolution

    Get PDF
    In this article we review the evidence of the impact of lesson study on student learning, teacher development, teaching materials, curriculum, professional learning and system enhancement. We argue for lesson study to be treated holistically as a vehicle for development and improvement at classroom, school and system levels rather than as a curricular or pedagogical intervention. We illustrate the need for this approach to evaluating lesson study through a complex case exemplar which used Research Lesson Study (a form of lesson study popular in the UK and Europe) to develop learning, teaching, curriculum and local improvement capacity across schools initially involved in a two-year mathematics curriculum development project that later evolved into three self-sustaining, voluntary lesson study school hubs in London. We discuss resulting changes in culture, practice, belief, expectation and student learning. We argue as a result for greater policy level understanding of this expanded conception of lesson study as a vehicle in classroom, school and system transformation.Both projects described received funding from the Greater London Authorit

    You made him be alive: Children’s perceptions of animacy in a humanoid robot

    Get PDF
    Social robots are becoming more sophisticated; in many cases they offer complex, autonomous interactions, responsive behaviors, and biomimetic appearances. These features may have significant impact on how people perceive and engage with robots; young children may be particularly influenced due to their developing ideas of agency. Young children are considered to hold naive beliefs of animacy and a tendency to mis-categorise moving objects as being alive but, with development, children can demonstrate a biological understanding of animacy. We experimentally explore the impact of children’s age and a humanoid’s movement on children’s perceptions of its animacy. Our humanoid’s behavior varied in apparent autonomy, from motionless, to manually operated, to covertly operated. Across conditions, younger children rated the robot as being significantly more person-like than older children did. We further found an interaction effect: younger children classified the robot as significantly more machine-like if they observed direct operation in contrast observing the motionless or apparently autonomous robot. Our findings replicate field results, supporting the modal model of the developmental trajectory for children’s understanding of animacy. We outline a program of research to both deepen the theoretical understanding of children’s animacy beliefs and develop robotic characters appropriate across key stages of child development

    Cross-Dimensional Mapping of Number, Length and Brightness by Preschool Children

    Get PDF
    Human adults in diverse cultures, children, infants, and non-human primates relate number to space, but it is not clear whether this ability reflects a specific and privileged number-space mapping. To investigate this possibility, we tested preschool children in matching tasks where the dimensions of number and length were mapped both to one another and to a third dimension, brightness. Children detected variation on all three dimensions, and they reliably performed mappings between number and length, and partially between brightness and length, but not between number and brightness. Moreover, children showed reliably better mapping of number onto the dimension of length than onto the dimension of brightness. These findings suggest that number establishes a privileged mapping with the dimension of length, and that other dimensions, including brightness, can be mapped onto length, although less efficiently. Children's adeptness at number-length mappings suggests that these two dimensions are intuitively related by the end of the preschool years

    Implementing a new mathematics curriculum in England: district Research Lesson Study as a driver for student learning, teacher learning and professional dialogue.

    Get PDF
    Against a backdrop of a transformation in teacher professional development and learning and state school organisation in England this century, this chapter describes a project which harnessed six cycles of Research Lesson Study at school and district level over two years to tailor the implementation of a new statutory curriculum in England to address the professional development needs of teachers and classroom learning needs of London students. It also reports the findings of research carried out during the project into how these teachers learned and developed this new curricular expertise and practice- knowledge through lesson study dialogues that supported student learning. It concludes by proposing future directions for teacher professional learning research and practice

    Impact of High Mathematics Education on the Number Sense

    Get PDF
    In adult number processing two mechanisms are commonly used: approximate estimation of quantity and exact calculation. While the former relies on the approximate number sense (ANS) which we share with animals and preverbal infants, the latter has been proposed to rely on an exact number system (ENS) which develops later in life following the acquisition of symbolic number knowledge. The current study investigated the influence of high level math education on the ANS and the ENS. Our results showed that the precision of non-symbolic quantity representation was not significantly altered by high level math education. However, performance in a symbolic number comparison task as well as the ability to map accurately between symbolic and non-symbolic quantities was significantly better the higher mathematics achievement. Our findings suggest that high level math education in adults shows little influence on their ANS, but it seems to be associated with a better anchored ENS and better mapping abilities between ENS and ANS
    • …
    corecore