Harkness learning: principles of a radical American pedagogy

This paper investigates and argues for Harkness learning: an approach to education that inculcates a culture of enquiry, driven by students in dialogue around a table. Tracing the history of the Harkness reforms in education at Phillips Exeter Academy, their pedagogical and philosophical roots are considered. Although partly inspired by the Oxford tutorial system and the Socratic concept of dialogue, Harkness departs from there to a radical classroom dynamic. The teacher is required to be more open-minded and less controlling over outcomes, to take the risk of listening more and saying less. This shift in emphasis fits with a distinctly American philosophical respect for the sanctity of the free thought and originality of the individual, which here is traced to Transcendentalist ideals that have permeated American culture. It can also be compared with Problem-Based Learning and there are certain significant overlaps between these pedagogies. However, Harkness is sometimes narrowly misunderstood as a technique for teaching, which takes the approach out of context. It needs to be understood in the broad frame of cultural reform of an institution – it is a useful symbol for a community committed to student discourse and problem solving. In this respect, Harkness owes a further debt to pragmatism – another great American philosophical-educational tradition

Disc pack cleaning table saves computer time

Disc pack holding table is support frame upon which computer disc pack is loaded and protective cover released. This combination permits manual off-line cleaning of disc pack storage units at any time without shutting down the computer, and eliminates on-line disc drive unit to hold pack during cleaning

Climate change: carbon losses in the Alps

The response of the terrestrial carbon cycle to global change is one of the main uncertainties in current climate change predictions1. Most terrestrial carbon is held in soils as organic matter derived from the decay of plant material (Fig. 1). Soil organic matter accounts for roughly three times more carbon than living vegetation, and for more carbon than vegetation and the atmosphere combined. Because elevated atmospheric CO2 concentrations have a fertilizing effect on plant growth, anthropogenic CO2 emissions have triggered increases in the land carbon sink2. However, models predict that other factors — such as water and nutrients — will eventually become limiting to plant growth, and hence to the land carbon sink. In contrast, the turnover of soil organic matter producing CO2 is expected to increase as the Earth warms. As a result, simulations using coupled carbon–climate models predict that the land surface will become a net source of CO2 before the end of the century, leading to a feedback loop between climate and soil carbon losses: increased emissions of CO2 from soil organic matter will lead to enhanced warming, which may then feedback to cause further soil organic matter losses. Prietzel and colleagues3, writing in Nature Geoscience, now provide evidence that warming has already caused a decline in soil organic matter in the German Alps

The Supernova Legacy Survey 3-year sample: Type Ia supernovae photometric distances and cosmological constraints

Aims. We present photometric properties and distance measurements of 252 high redshift Type Ia supernovae (0.15 < z < 1.1) discovered during the first three years of the Supernova Legacy Survey (SNLS). These events were detected and their multi-colour light curves measured using the MegaPrime/MegaCam instrument at the Canada-France-Hawaii Telescope (CFHT), by repeatedly imaging four one-square degree fields in four bands. Follow-up spectroscopy was performed at the VLT, Gemini and Keck telescopes to confirm the nature of the supernovae and to measure their redshifts. Methods. Systematic uncertainties arising from light curve modeling are studied, making use of two techniques to derive the peak magnitude, shape and colour of the supernovae, and taking advantage of a precise calibration of the SNLS fields. Results. A flat ΛCDM cosmological fit to 231 SNLS high redshift type Ia supernovae alone gives Ω_M = 0.211 ± 0.034(stat) ± 0.069(sys). The dominant systematic uncertainty comes from uncertainties in the photometric calibration. Systematic uncertainties from light curve fitters come next with a total contribution of ± 0.026 on Ω_M. No clear evidence is found for a possible evolution of the slope (β) of the colour-luminosity relation with redshift

The effects of cervical muscle fatigue on balance - A study with elite amateur rugby league players

Neck muscle fatigue has been shown to alter an individual’s balance in a similar way to that reported in subjects suffering from neck pain or subjects that have suffered a neck injury. The main purpose of the present study was to quantify the effects of neck fatigue on neck muscle electromyography (EMG) activity, balance, perceived fatigue and perceived stability. Forty four elite amateur rugby league players resisted with their neck muscles approximately 35% maximum voluntary isometric contraction (MVIC) force for 15 minutes in eight different directions. Sway velocity and surface electromyography were measured. Questionnaires were used to record perceived effort and stability. Repeated measures ANOVA showed that after 15 minutes isometric contraction, significant changes were seen in sway velocity, perceived sway and EMG median frequency. There were no differences in perceived efforts. The changes in sway velocity and median frequency were more pronounced after extension and right and left posterior oblique contractions but there was no significant difference in sway velocity after contraction in the right lateral flexion, right anterior oblique and left anterior oblique direction of contraction. All the subjects showed oriented whole-body leaning in the plane of the contraction. The experiment produced significantly altered and perceived altered balance in this group of physically fit individuals. The results may contribute to our understanding of normal functional capacities of athletes and will provide a basis for further investigation in healthy non-athletes and participants that have suffered neck injuries. This may ultimately help develop accurate and valid rehabilitation outcome measures

Langlands parameters for epipelagic representations of GLn\text{\rm GL}_n

Let $F$ be a non-Archimedean local field. An irreducible cuspidal representation of $\text{\rm GL}_n(F)$ is epipelagic if its Swan conductor equals 1. We give a full and explicit description of the Langlands parameters of such representations.Comment: 25 page

Tame multiplicity and conductor for local Galois representations

Let $F$ be a non-Archimedean locally compact field of residual characteristic $p$. Let $\sigma$ be an irreducible smooth representation of the absolute Weil group \Cal W_F of $F$ and \sw(\sigma) the Swan exponent of $\sigma$. Assume \sw(\sigma) \ge1. Let \Cal I_F be the inertia subgroup of \Cal W_F and \Cal P_F the wild inertia subgroup. There is an essentially unique, finite, cyclic group $\varSigma$, of order prime to $p$, so that \sigma(\Cal I_F) = \sigma(\Cal P_F)\varSigma. In response to a query of Mark Reeder, we show that the multiplicity in $\sigma$ of any character of $\varSigma$ is bounded by \sw(\sigma).Comment: Revised version with further detai