Student learning and cognition in cooperative small groups : towards a fourth metaphor of human learning

Research into the benefits of cooperative learning has focussed most attention onto a social psychological perspective with the result that the putative cognitive benefits of these strategies have not been thoroughly researched and clearly delineated. One consequence of this research focus has been that cooperative learning strategies are not always adopted by teachers and included permanently into their regular classroom practice, thereby possibly denying some students the potential for cognitive gain. This study was conceived originally as an investigation into the claimed cognitive benefits of small-group cooperative learning from a cognitive perspective but the investigation of the cooperative learning literature also led to an investigation of the general learning literature base. Recent research suggested that human learning might not have been described adequately by the earlier perspectives. Some authors contended that a fourth metaphor of human learning may be emerging from the socio-cultural perspectives. Investigating how students learn in cooperative situations was seen as a potential vehicle for the wider investigation of a fourth metaphor. It was against this background that the present study was undertaken. Learning was not seen in terms of a dichotomy between the main cognitivist and socially based perspectives so a pluralist approach was adopted in this study in an attempt to reconcile some of the differences between the main perspectives. Process-product research has been criticised for providing a narrow view of the classroom lives of students. Additionally, critics of laboratory-based research have argued for research to regain its connection with real classroom settings. Given the contentions of several authors, this study was conceived as non-positivist, naturalistic and pluralist within the post-modernist era. Five groups of students at two schools were recruited for this qualitative case study. The students\u27 learning from five purpose-designed lessons was tracked through their transcribed discussions and their recall in learning journals . Journal data were collected as much as twelve months after the last lesson was completed, enabling the longitudinal tracking of student learning. A major finding of the research was the strong mediational effects on student learning of the classroom context and the group within the classroom. The nature of student talk also impacted strongly upon student learning. Evidence was found of both individual and social construction of knowledge. Knowledge sometimes seemed to appear initially as a group construct but was later modified significantly by the students\u27 individual minds. Although all knowledge originated in socio-cultural contexts, usually through the ultimate human social semiotic of language, the final form of the knowledge appeared highly individual and idiosyncratic. The idiosyncratic nature of the students\u27 learning led the researcher to posit that knowledge resided in the individual neural structures of the brain. This mind-as-brain proposition was advanced as a contribution towards a fourth metaphor of human learning. The findings suggested several implications for teachers about the recommended procedures for small-group cooperative learning. Implications for research included further neuroscience investigations into human learning because of the potential for this kind of research to inform practice

Teacher planning in a era of accountability for student outcomes

The focus of the study of teaching has shifted gradually away from the process-product research paradigm to one which emphasizes the role of teacher and student thought processes. Researchers have identified teacher planning as an area of study likely provide insights into the role of teacher thought processes. Since the nineteen seventies a number of important studies into teacher planning have been completed. An examination of the teacher planning literature revealed that certain types and functions of planning recur in the research. The literature also shows that the rational-linear planning models which are prevalent in teacher pre-service education do not adequately describe teacher planning in practice. Several studies have attempted to describe teacher planning in terms of models. Although these studies more closely described actual teacher planning, modelling of teacher planning is incomplete. Some research has also attempted to establish relationships between teacher planning and teacher actions and the subsequent outcomes for students. Western Australian schools are presently subject to a climate of change driven principally by economic considerations. A fundamental shift in emphasis has occurred in teacher accountability policy and as a result teachers are now accountable for the outcomes of students instead of the traditional accountability for planning programmes of work. Case study techniques were used to examine the extent to which these policy changes and the associated de-regulation have affected the planning practices of six teachers, The thought processes involved in planning were described and a naturalistic model of planning was developed. The study found that the teachers did not plan as they should in two respects. First, they only applied rational models. Then using planning formats which assisted them with the writing of objectives. In this respect the teachers did not apply the rational models from their pre-service education, Second, the teachers did not apply an outcomes approach to planning, as required by the Education Department accountability policy. The study also examined the six teachers\u27 perceptions of accountability and the accountability techniques applied in two schools. The teachers perceived accountability as a professional obligation. Teachers were not being held accountable for planning within the school management information system. Although the focus for accountability discussions had shifted to accountability for student outcomes, the teachers continued to apply an activities-first approach to planning

Gamma-Ray Burst Polarization: Limits from RHESSI Measurements

Using the RHESSI satellite as a Compton polarimeter, a recent study claimed that the prompt emission of GRB021206 was almost fully linearly polarized. This was challenged by a subsequent reanalysis. We present an novel approach, applying our method to the same data. We identify Compton scattering candidates by carefully filtering events in energy, time, and scattering geometry. Our polarization search is based on time dependent scattering rates in perpendicular directions, thus optimally excluding systematic errors. We perform simulations to obtain the instrument's polarimetric sensitivity, and these simulations include photon polarization. For GRB021206, we formally find a linear polarization degree of 41% (+57% -44%), concluding that the data quality is insufficient to constrain the polarization degree in this case. We further applied our analysis to GRB030519B and found again a null result.Comment: 39 pages, 11 figures, accepted for publication by the Astrophysical Journa

Almost reducibility for finitely differentiable SL(2,R)-valued quasi-periodic cocycles

Quasi-periodic cocycles with a diophantine frequency and with values in SL(2,R) are shown to be almost reducible as long as they are close enough to a constant, in the topology of k times differentiable functions, with k great enough. Almost reducibility is obtained by analytic approximation after a loss of differentiability which only depends on the frequency and on the constant part. As in the analytic case, if their fibered rotation number is diophantine or rational with respect to the frequency, such cocycles are in fact reducible. This extends Eliasson's theorem on Schr\"odinger cocycles to the differentiable case

RHESSI as Gamma Ray Burst Polarimeter

The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) was designed to measure hard X-rays and γ-rays from solar flares. With its big detection area and thin side shielding it also proved to be well suited for studying Gamma Ray Bursts (GRB). Polarization analysis is feasible as well, due to a big modulation factor (MF), though serious constraints on the minimum detectable polarization (MDP) come from detection efficiency of double scattered photons. More constraints are given by background of accidental and real coincidences

Radiation environment along the INTEGRAL orbit measured with the IREM monitor

The INTEGRAL Radiation Environment Monitor (IREM) is a payload supporting instrument on board the INTEGRAL satellite. The monitor continually measures electron and proton fluxes along the orbit and provides this information to the spacecraft on board data handler. The mission alert system broadcasts it to the payload instruments enabling them to react accordingly to the current radiation level. Additionally, the IREM conducts its autonomous research mapping the Earth radiation environment for the space weather program. Its scientific data are available for further analysis almost without delay.Comment: 5 pages, 7 figures, accepted for publication in A+A letter

Spectral Analysis of GRBs Measured by RHESSI

The Ge spectrometer of the RHESSI satellite is sensitive to Gamma Ray Bursts (GRBs) from about 40 keV up to 17 MeV, thus ideally complementing the Swift/BAT instrument whose sensitivity decreases above 150 keV. We present preliminary results of spectral fits of RHESSI GRB data. After describing our method, the RHESSI results are discussed and compared with Swift and Konus.Comment: 4 pages, 4 figures, conference proceedings, 'Swift and GRBs: Unveiling the Relativistic Universe', San Servolo, Venice, 5-9 June 2006, to appear in Il Nouvo Ciment

Leader corruption depends on power and testosterone

We used incentivized experimental games to manipulate leader power-the number of followers and the discretion leaders had to enforce their will. Leaders had complete autonomy in deciding payouts to themselves and their followers. Although leaders could make prosocial decisions to benefit the public good they could also abuse their power by invoking antisocial decisions, which reduced the total payouts to the group but increased leader's earnings. In Study 1 (N = 478), we found that both amount of followers and discretionary choices independently predicted leader corruption. In Study 2 (N = 240), we examined how power and individual differences (e.g., personality, hormones) affected leader corruption over time; power interacted with testosterone in predicting corruption, which was highest when leader power and baseline testosterone were both high. Honesty predicted initial level of leader antisocial decisions; however, honesty did not shield leaders from the corruptive effect of power

Polarization from GRB021206: No constraints from reanalysis of RHESSI data

The determination of a polarization signal in Gamma Ray Bursts (GRBs) would give new information about their nature and mechanism. Using the RHESSI satellite as a Compton polarimeter, Coburn W. and Boggs S. E. (Nature, 423 (2003) 415) reported that GRB021206 was highly linearly polarized. This was contradicted by Rutledge R. E. and Fox D. B. (Mon. Not. R. Astron. Soc., 350 (2004) 1288) who found about 10 times less scattering events suitable for measuring polarization. Applying our own method to thesamedata weconfirm them uch lower number of suitable scattering events. But we obtain three times smaller errors by using better selection criteria. Comparison with our Monte Carlo simulations shows that from the RHESSI data of GRB021206 we cannot distinguish between no and full polarization within less than 2 standard deviations. We also applied our method to other GRBs observed by RHESSI. This shows that the probability to observe a GRB suitable for polarization search with such an instrument is small

Virtual water highway: water use efficiency in global food trade

International audienceAmid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the regional, national and global water budget has received much attention in recent years. Built upon the knowledge of virtual water accounting in the literature, this study examines the efficiency of the resource use embodied in the global virtual water trade from the perspectives of exporting and importing countries. Different characteristics between "green" and "blue" virtual water corresponding to rainfed and irrigated agriculture are elaborated. The investigation reveals that the virtual water flows primarily from countries of high water productivity to countries of low water productivity, generating a global saving of water resources. Meanwhile, the domination of green virtual water in the total virtual water trade constitutes low opportunity costs and environmental impacts as opposed to blue virtual water. The results suggest efficiency gains in the global food trade in terms of water resource utilization. The study raises awareness of negative impacts of increasing reliance on irrigation for food production in many countries, including food exporting countries. The findings of the study call for a greater emphasis on rainfed agriculture to improve global food security and environmental sustainability