12,395 research outputs found

    What does social semiotics have to offer mathematics education research?

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    Affordances of spreadsheets in mathematical investigation: Potentialities for learning

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    This article, is concerned with the ways learning is shaped when mathematics problems are investigated in spreadsheet environments. It considers how the opportunities and constraints the digital media affords influenced the decisions the students made, and the direction of their enquiry pathway. How might the leraning trajectory unfold, and the learning process and mathematical understanding emerge? Will the spreadsheet, as the pedagogical medium, evoke learning in a distinctive manner? The article reports on an aspect of an ongoing study involving students as they engage mathematical investigative tasks through digital media, the spreadsheet in particular. In considers the affordances of this learning environment for primary-aged students

    Calibration of a general optical equation for remote sensing of suspended sediments in a moderately turbid estuary

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    Abstract A general algorithm for determining suspended sediment concentrations in the surface waters of estuaries has been developed for use with satellite data. The algorithm uses a three-parameter general optical equation to relate suspended sediment concentrations to water reflectances that have been corrected for sun angle effects, atmospheric path radiance, and tidal excursion. Using data collected by the advanced very high resolution radiometer on five different dates, reflectances were determined using two different methods, one providing maximum correction for haze and the other providing minimum sensitivity to pigments. For both methods, in situ and remotely sensed samples from Delaware Bay acquired within 3.5 hours of each other agreed to within 60% at the 95% confidence level. Pixel and subpixel scale spatial variations and variability associated with in situ measurements produced about 50% of the differences. Chlorophyll concentrations of \u3e50 ÎŒg/L produced a discrepancy in the reflectance method that provided the best haze correction. The parameter values may be adjusted to allow for variations in sediment size and pigment variations, allowing application of the calibration to estuaries having optically different suspended sediments
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