It's just a word : CALL, French verbs and mixed-ability pupils

This thesis follows the trail of a perennial problem in the written work of pupils studying GCSE French, and suggests a CALL solution. The motivation for the research lies in the decline of grammatical accuracy, particularly in verb use, in the French produced by mixed-ability pupils and university students alike.Theories of language acquisition are assessed and a limited amount of guidance emerges. French GCSE Examiners' Reports then provide a firm foundation for research with their suggestion that the rise in oral work has affected written standards. A review of the literature reveals a wide range of barriers to verb learning. These can be classified as linguistic, psycholinguistic and pedagogic.One of the most impenetrable barriers is the redundancy of many verb endings. Empirical evidence from written and interview data is presented to show the startling kinds of misconceptions held by many pupils about verbs,and the complex of systems learners devise to solve problems.The thesis then proposes an explicit grammar-teaching approach based on principles of pedagogical grammar. Current Computer Assisted Language Learning (CALL) approaches to verb teaching offer admirable formal practice for able pupils but do not cater for the difficulties experienced by less able learners, who may therefore be disenfranchised. Detailed proposals are given for the creation of 'mixed-ability CALL' for verb learning, followed by a description of the design and production processes of three new programs aimed at less able pupils. Further empirical work is undertaken with GCSE pupils in order to assess the effects of tutorial, game and 'cognitive' CALL approaches. The quantitative data show that written performance can improve after using these programs. However, the most striking result of CALL intervention is the transformation of weak pupils' spoken metalanguage from restricted grammatical expression to accurate verb articulation within a short space of time

Gelfand–Tsetlin polytopes and random contractions away from the limiting shape.

In this paper, we consider a sequence of selfadjoint matrices An having a limiting spectral distribution as n → ∞, and we consider a sequence of full flags ｛0 ≤ p₁(n) ≤ ... ≤ pi(n) ≤ ... ≤ 1n｝ chosen at random according to the uniform measure on full flag manifolds. We are interested in the behaviour of the extremal eigenvalues of pi(n)Anpi(n). This problem is known to be equivalent to the study of uniform probability measures on Gelfand–Tsetlin polytopes. Our main results consist in explicit uniform estimates for extremal eigenvalues, and the fact that an outlier behavior has an exponentially small probability. This problem is of intrinsic interest in random matrix theory, but it was motivated from a problem in Quantum Information Theory, which we discuss. The proofs rely on a reinterpretation of the problem with the help of determinantal point processes and the techniques are based on steepest descent analysis.Dans cet article, nous nous intéressons à une suite de matrices autoadjointes An possédant une distribution spectrale lorsque n → ∞, et nous étudions une suite de drapeaux complets ｛0 ≤ p₁(n) ≤ ... ≤ pi(n) ≤ ... ≤ 1n｝ choisis au hasard selon la loi uniforme sur les varietes drapeaux complètes. Nous nous intéressons au comportement des valeurs propres extrêmes de pi(n)Anpi(n). Il est connu que ce problème est équivalent à l'étude de la mesure de probabilité uniforme sur des polytopes de Gelfand–Tsetlin. Notre résultat principal consiste en des estimées uniformes pour des valeurs propres extrémales, et le fait que les outliers sont de probabilité exponentiellement petite. Ce problème revêt un interêt intrinsèque en matrices aléatoires ; par ailleurs, il trouve une motivation dans des questions d'information quantique que nous évoquons aussi. Les preuves se fonde sur une interpretation du problème a l'aide de processus de points déterminantaux, et les techniques reposent sur de l'analyse de type « steepest descent »

How to estimate a cumulative process’s rate-function

Consider two sequences of bounded random variables, a value and a timing process, that satisfy the large deviation principle (LDP) with rate-function J(·,·) and whose cumulative process satisfies the LDP with rate-function I(·). Under mixing conditions, an LDP for estimates of I constructed by transforming an estimate of J is proved. For the case of cumulative renewal processes it is demonstrated that this approach is favorable to a more direct method as it ensures the laws of the estimates converge weakly to a Dirac measure at I

How to estimate a cumulative process’s rate-function

Consider two sequences of bounded random variables, a value and a timing process, that satisfy the large deviation principle (LDP) with rate-function J(·,·) and whose cumulative process satisfies the LDP with rate-function I(·). Under mixing conditions, an LDP for estimates of I constructed by transforming an estimate of J is proved. For the case of cumulative renewal processes it is demonstrated that this approach is favorable to a more direct method as it ensures the laws of the estimates converge weakly to a Dirac measure at I

The implications of lung-regulated buoyancy control for dive depth and duration

Among air-breathing divers, control of buoyancy through lung volume regulation may be most highly developed in marine turtles. In short, the turtle lung may serve a dual role as both an oxygen store and in buoyancy control. A simple model is developed to show that, for turtles diving up to the maximum depth at which they can still use their lungs to attain neutral buoyancy, the total oxygen store will increase greatly with dive depth, and hence a corresponding increase in dive duration is predicted. Time–depth recorders attached to free-living green turtles (Chelonia mydas) at Ascension Island confirmed a marked increase in dive duration with depth, with the gradient of this relationship being >10 times that seen in diving birds and mammals. Consistent with the prediction that the lungs serve a dual role, we found that, when lead weights were added to some turtles to increase their specific gravity, the mean depth of dives decreased, but for dives to the same depth, weighted animals dived for longer. The depth distribution of green turtles seems to be generally constrained by the maximum depth at which they can still attain close to neutral buoyancy

Spatial and temporal changes in Bax subcellular localization during anoikis

Bax, a member of the Bcl-2 family, translocates to mitochondria during apoptosis, where it forms oligomers which are thought to release apoptogenic factors such as cytochrome c. Using anoikis as a model system, we have examined spatial and temporal changes in Bax distribution. Bax translocates to mitochondria within 15 min of detaching cells from extracellular matrix, but mitochondrial permeabilization does not occur for a number of hours. The formation of Bax oligomers and perimitochondrial clusters occurs concomitant with caspase activation and loss of mitochondrial membrane potential, before nuclear condensation. Cells can be rescued from apoptosis if they are replated onto extracellular matrix within an hour, whereas cells detached for longer could not. The loss of ability to rescue cells from anoikis occurs after Bax translocation, but before the formation of clusters and cytochrome c release. Our data suggest that Bax regulation occurs at several levels, with formation of clusters a late event, and with critical changes determining cell fate occurring earlier