The role and effects of teaching assistants in English primary schools (Years 4 to 6) 2000-2003. Results from the Class Size and Pupil-Adult Ratios (CSPAR) KS2 Project

It is widely assumed that increasing the number of Teaching Assistants (TAs) in the classroom will be beneficial to children, and this is one important aim of the recently implemented Workforce Agreement. But there are still significant gaps in knowledge about many aspects of their deployment and impact. The Class Size and Pupil-Adult Ratio (CSPAR) KS2 study built on earlier findings when the pupils were in reception and KS1 and investigated: 1. the deployment of TAs in classrooms and how key parties involved perceived this; 2. the effect of TAs on interactions involving pupils and teachers in the same classrooms, and on pupil attainments. The study had a longitudinal, mixed method and multi-informant design. There were 202 schools, 332 classes and 8728 pupils in Y4. Methods of data collection included: for the whole sample) questionnaires completed by TAs, teachers and head teachers, assessments of pupil attainments in mathematics, English and science, data on pupil background, and (for a sub-sample) case studies and a systematic observation study. This study found that the TA’s role in KS2 is predominantly a direct one, in the sense of face-to-face interactions supporting certain pupils. There was no evidence that the presence of TAs, or any characteristic of TAs, had a measurable effect on pupil attainment. However, results were clear in showing that TAs had an indirect effect on teaching, e.g., pupils had a more active form of interaction with the teacher and there was more individualised teacher attention. This supported teachers’ views that TAs are effective in supporting them in this way. We conclude that more attention needs to be paid to what we call the pedagogical role of TAs so that they can be used effectively to help teachers and pupils, particularly in the context of the enhanced roles for TAs being introduced as part of the Government’s remodeling agenda

Reentrant Adhesion Behavior in Nanocluster Deposition

We simulate the collision of atomic clusters with a weakly attractive surface using molecular dynamics in a regime between soft-landing and fragmentation, where the cluster undergoes large deformation but remains intact. As a function of incident kinetic energy, we find a transition from adhesion to reflection at low kinetic energies. We also identify a second adhesive regime at intermediate kinetic energies, where strong deformation of the cluster leads to an increase in contact area and adhesive energy.Comment: 7 pages, 6 figure

Intellectual property rights and product effectiveness

Recent economic literature concludes that an invention-importing country, where domestic invention is scarce or nonexistent, may reduce its welfare and, in some cases, world welfare, by protecting intellectual property developed elsewhere. The analysis presented in this article uses economic theory to show that such a conclusion may not be fully warranted for a wide range of products, such as antibiotics, fungicides, herbicides, and pesticides, whose effectiveness diminishes with cumulative use. Both developed and developing countries may find that protecting intellectual property rights for these products will enhance welfare - even when their invention is provided for free.Intellectual property ; Imports

Dye laser remote sensing of marine plankton

Dye laser, emitting four wavelengths sequentially in time, has been incorporated into helicopter-borne lidar flight package, for performing studies of laser-induced fluorescence of chlorophyll A in algae. Data obtained by multicolor lidar technique can provide water-resource management with rapid-access wide-area coverage of the impact of various environmental factors for any body of water

Molecular dynamics simulations of reflection and adhesion behavior in Lennard-Jones cluster deposition

We conduct molecular dynamics simulations of the collision of atomic clusters with a weakly-attractive surface. We focus on an intermediate regime, between soft-landing and fragmentation, where the cluster undergoes deformation on impact but remains largely intact, and will either adhere to the surface (and possibly slide), or be reflected. We find that the outcome of the collision is determined by the Weber number, We i.e. the ratio of the kinetic energy to the adhesion energy, with a transition between adhesion and reflection occurring as We passes through unity. We also identify two distinct collision regimes: in one regime the collision is largely elastic and deformation of the cluster is relatively small but in the second regime the deformation is large and the adhesion energy starts to depend on the kinetic energy. If the transition between these two regimes occurs at a similar kinetic energy to that of the transition between reflection and adhesion, then we find that the probability of adhesion for a cluster can be bimodal. In addition we investigate the effects of the angle of incidence on adhesion and reflection. Finally we compare our findings both with recent experimental results and with macroscopic theories of particle collisions.Comment: 18 pages, 13 figure

Smart Materials as Intelligent Insulation

In order to provide a robust infrastructure for the transmission and distribution of electrical power, understanding and monitoring equipment ageing and failure is of paramount importance. Commonly, failure is associated with degradation of the dielectric material; therefore the introduction of a smart moiety into the material is a potentially attractive means of continual condition monitoring. It is important that any introduction of smart groups into the dielectric does not have any detrimental effect on the desirable electrical and mechanical properties of the bulk material. Initial work focussed on the introduction of fluorophores into a model dielectric system. Fluorescence is known to be a visible effect even at very low concentrations of active fluorophores and therefore was thought well suited to such an application. It was necessary both to optimise the active fluorophore itself and to determine the most appropriate manner in which to introduce the fluorophores into the insulating system. This presentation will describe the effect of introducing fluorophores into polymeric systems on the dielectric properties of the material and the findings thus far [1]. Alternative smart material systems will also be discussed along with the benefits and limitations of smart materials as electric field sensors

Regularized energy-dependent solar flare hard x-ray spectral index

The deduction from solar flare X-ray photon spectroscopic data of the energy dependent model-independent spectral index is considered as an inverse problem. Using the well developed regularization approach we analyze the energy dependency of spectral index for a high resolution energy spectrum provided by Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The regularization technique produces much smoother derivatives while avoiding additional errors typical of finite differences. It is shown that observations imply a spectral index varying significantly with energy, in a way that also varies with time as the flare progresses. The implications of these findings are discussed in the solar flare context.Comment: 13 pages; 5 figures, Solar Physics in pres

The spectral evolution of impulsive solar X-ray flares. II.Comparison of observations with models

We study the evolution of the spectral index and the normalization (flux) of the non-thermal component of the electron spectra observed by RHESSI during 24 solar hard X-ray flares. The quantitative evolution is confronted with the predictions of simple electron acceleration models featuring the soft-hard-soft behaviour. The comparison is general in scope and can be applied to different acceleration models, provided that they make predictions for the behavior of the spectral index as a function of the normalization. A simple stochastic acceleration model yields plausible best-fit model parameters for about 77% of the 141 events consisting of rise and decay phases of individual hard X-ray peaks. However, it implies unphysically high electron acceleration rates and total energies for the others. Other simple acceleration models such as constant rate of accelerated electrons or constant input power have a similar failure rate. The peaks inconsistent with the simple acceleration models have smaller variations in the spectral index. The cases compatible with a simple stochastic model require typically a few times 10^36 electrons accelerated per second at a threshold energy of 18 keV in the rise phases and 24 keV in the decay phases of the flare peaks.Comment: 9 pages, 4 figures, accepted for publication by A&