Open ended tasks and barriers to learning : teachers\u27 perspectives

Examines barriers to learning mathematics when using an open-ended task teaching strategy. Features of an open-ended task; Benefits of an open-ended task; Problems concerning multiplicity of responses and contexts in an open-ended task.<br /

A Calibrated Measurement of the Near-IR Continuum Sky Brightness Using Magellan/FIRE

We characterize the near-IR sky background from 308 observations with the FIRE spectrograph at Magellan. A subset of 105 observations selected to minimize lunar and thermal effects gives a continuous, median spectrum from 0.83 to 2.5 microns which we present in electronic form. The data are used to characterize the broadband continuum emission between atmospheric OH features and correlate its properties with observing conditions such as lunar angle and time of night. We find that the moon contributes significantly to the inter-line continuum in the Y and J bands whereas the observed H band continuum is dominated by the blended Lorentzian wings of multiple OH line profiles even at R=6000. Lunar effects may be mitigated in Y and J through careful scheduling of observations, but the most ambitious near-IR programs will benefit from allocation during dark observing time if those observations are not limited by read noise. In Y and J our measured continuum exceeds space-based average estimates of the Zodiacal light, but it is not readily identified with known terrestrial foregrounds. If further measurements confirm such a fundamental background, it would impact requirements for OH-suppressed instruments operating in this regime.Comment: 25 pages, 11 figures, accepted to PAS

Planning and teaching mathematics lessons as a dynamic, interactive process

We are researching actions that teachers can take to improve mathematics learning for all students, with particular attention to specific groups of students who might experience difficulty. After identifying possible barriers to learning, we offered teachers mathematics lessons structured in a particular way. Teachers&rsquo; use of the model outlined in this paper seemed productive and their resulting planning and teaching proved to be dynamic and interactive. This paper uses excerpts from a conversation between two teachers to illustrate specific aspects of the model.<br /

The Water Poverty Index: an International Comparison

This paper reports on the construction of an International Water Poverty Index, part of the first phase of a research project into building a locally based version of the index. The purpose of the Water Poverty Index is to express an interdisciplinary measure which links household welfare with water availability and indicates the degree to which water scarcity impacts on human populations. Such an index makes it possible to rank countries and communities within countries taking into account both physical and socio-economic factors associated with water scarcity. This enables national and international organisations concerned with water provision and management to monitor both the resources available and the socio-economic factors which impact on access and use of those resources. This paper presents details of the methodology used and the results obtained for 140 countries covering measures of resources, access, capacity, use and environment.Indicators, water, environment, water poverty, income poverty

Session 5: Development, Neuroscience and Evolutionary Psychology

Proceedings of the Pittsburgh Workshop in History and Philosophy of Biology, Center for Philosophy of Science, University of Pittsburgh, March 23-24 2001 Session 5: Development, Neuroscience and Evolutionary Psycholog

Near-Infrared InGaAs Detectors for Background-limited Imaging and Photometry

Originally designed for night-vision equipment, InGaAs detectors are beginning to achieve background-limited performance in broadband imaging from the ground. The lower cost of these detectors can enable multi-band instruments, arrays of small telescopes, and large focal planes that would be uneconomical with high-performance HgCdTe detectors. We developed a camera to operate the FLIR AP1121 sensor using deep thermoelectric cooling and up-the-ramp sampling to minimize noise. We measured a dark current of 163$~e$- s$^{-1}$ pix$^{-1}$, a read noise of 87$~e$- up-the-ramp, and a well depth of 80k$~e$-. Laboratory photometric testing achieved a stability of 230 ppm hr$^{-1/2}$, which would be required for detecting exoplanet transits. InGaAs detectors are also applicable to other branches of near-infrared time-domain astronomy, ranging from brown dwarf weather to gravitational wave follow-up.Comment: Submitted to Proc. SPIE, Astronomical Telescopes + Instrumentation (2014

Precision of a Low-Cost InGaAs Detector for Near Infrared Photometry

We have designed, constructed, and tested an InGaAs near-infrared camera to explore whether low-cost detectors can make small (<1 m) telescopes capable of precise (<1 mmag) infrared photometry of relatively bright targets. The camera is constructed around the 640x512 pixel APS640C sensor built by FLIR Electro-Optical Components. We designed custom analog-to-digital electronics for maximum stability and minimum noise. The InGaAs dark current halves with every 7 deg C of cooling, and we reduce it to 840 e-/s/pixel (with a pixel-to-pixel variation of +/-200 e-/s/pixel) by cooling the array to -20 deg C. Beyond this point, glow from the readout dominates. The single-sample read noise of 149 e- is reduced to 54 e- through up-the-ramp sampling. Laboratory testing with a star field generated by a lenslet array shows that 2-star differential photometry is possible to a precision of 631 +/-205 ppm (0.68 mmag) hr^-0.5 at a flux of 2.4E4 e-/s. Employing three comparison stars and de-correlating reference signals further improves the precision to 483 +/-161 ppm (0.52 mmag) hr^-0.5. Photometric observations of HD80606 and HD80607 (J=7.7 and 7.8) in the Y band shows that differential photometry to a precision of 415 ppm (0.45 mmag) hr^-0.5 is achieved with an effective telescope aperture of 0.25 m. Next-generation InGaAs detectors should indeed enable Poisson-limited photometry of brighter dwarfs with particular advantage for late-M and L types. In addition, one might acquire near-infrared photometry simultaneously with optical photometry or radial velocity measurements to maximize the return of exoplanet searches with small telescopes.Comment: Accepted to PAS

Exploring the relationship between task, teacher actions, and student learning

We are examining actions that teachers take to convert tasks into learning opportunities. In this paper, we contrast ways that three teachers convert the same task into lessons, and the way that their lessons reflect their intent. We found that the teachers did what they intended to do, that this was connected to their appreciation of the mathematics involved, and directly influenced the learning opportunities of the students. To the extent that the potential of the task was reduced, this seemed due to the lack of mathematical confidence in the case of two of the teachers

A global climatology of wind–wave interaction

Generally, ocean waves are thought to act as a drag on the surface wind so that momentum is transferred downwards, from the atmosphere into the waves. Recent observations have suggested that when long wavelength waves, characteristic of remotely generated swell, propagate faster than the surface wind momentum can also be transferred upwards. This upward momentum transfer acts to accelerate the near-surface wind, resulting in a low-level wave-driven wind jet. Previous studies have suggested that the sign reversal of the momentum flux is well predicted by the inverse wave age, the ratio of the surface wind speed to the speed of the waves at the peak of the spectrum. ECMWF ERA-40 data has been used here to calculate the global distribution of the inverse wave age to determine whether there are regions of the ocean that are usually in the wind-driven wave regime and others that are generally in the wave-driven wind regime. The wind-driven wave regime is found to occur most often in the mid-latitude storm tracks where wind speeds are generally high. The wave-driven wind regime is found to be prevalent in the tropics where wind speeds are generally light and swell can propagate from storms at higher latitudes. The inverse wave age is also a useful indicator of the degree of coupling between the local wind and wave fields. The climatologies presented emphasise the non-equilibrium that exists between the local wind and wave fields and highlight the importance of swell in the global oceans

Teaching Mathematics: Using research-informed strategies

AER 59 reviews research into aspects of mathematics teaching, focusing on issues relevant to Australian mathematics teachers, to those who support them, and also to those who make policy decisions about mathematics teaching. It was motivated by and draws on the proceedings of the well-attended and highly successful ACER Research Conference Teaching mathematics? Make it count: What research tells us about effective mathematics teaching and learning, held in Melbourne in August 2010. Section 2 describes the goals of teaching mathematics and argues that a practical orientation should be the focus of mathematics teaching in the compulsory years, and outlines the contribution numeracy-based perspectives can make to schooling. Section 3 uses assessment data to evaluate how well those goals are being met in Australia and introduces the challenge of seeking equity of opportunity in mathematics teaching and learning. Section 4 expands on the importance, to individuals and society, of achieving the mathematics goals; and Section 5 discusses six research-based principles of mathematics teaching. Section 6 argues for the importance of well-chosen mathematical tasks in supporting student learning, and models tasks and particular teaching strategies. Sections 7 and 8 analyse research which provides insights into a key issue facing Australian mathematics teachers, that of finding ways to address the needs of heterogeneous groups of students. Section 9 describes and recommends particular emphases and strategies for education programs for both prospective and practising teachers.https://research.acer.edu.au/aer/1022/thumbnail.jp