Dyscalculia in further and higher education

Dyscalculia is one of the newer challenges that face practitioners and researchers, particularly in the post 16 sectors. The focus of this paper is therefore be Further and Higher Education. Dyscalculia is a specific learning difference, which affects the ability to acquire arithmetical skills and an intuitive grasp of numbers. Consideration is given to this and other current definitions, together with a theoretical perspective. The paper also considers the prevalence of dyscalculia, as well as the difficulties dyscalculic students’ experience, both in academic life and more generally. The paper highlights DysCalculiUM, a new first-line screening tool for dyscalculia focusing on the understanding of mathematics. The system provides an on-line delivery of the screening tool to identify students at risk with minimal staff input. A Profiler identifies students requiring further investigation. This may take the form of an in-depth interview and referral for further testing. The final section of the paper considers subsequent one-to-one support for students. A case study of a dyscalculic student in Higher Education working with tables of information, percentages and graphs, serves to illustrate some of the ways in which dyscalculic students can be supported on a one-to-one basis

Reachable Sets Approach to Multiobjective Problems and its Possible Applications to Water Resources Management in the Skane Region

Decision making in a lot of resources supply and resources allocation problems is related to sophisticated multiobjective analysis. The concept of a man-computer simulation system was suggested as a tool for decision making in problems of this kind, especially in the case of water resources (Moiseev et al. 1980). Within the framework of such a system the analyst and the expert employ a full range of operational research methods (simulation, optimization, multiobjective, informal and game-theoretical ones) to address multiobjective problems by means of the hierarchical system of mathematical models of the system under study. Various forms of mathematical models can be studied by means of simulation experiments. To establish control variables (to formulate scenarios) in a simulation study the expert may use optimization techniques applied to models simpler than the simulation ones. It is reasonable to study the problem of criteria formulation in optimization problems (the objectives convolution problem) by means of multiobjective techniques and simple (screening) models. The multiobjective study is the most important part of investigation based on the simulation system, because it is the multiobjective investigation that gives a general understanding of the system under study. This paper treats a new approach to multiobjective problems investigation. This approach is called the Generalized Reachable Sets (GRS) approach and belongs to generating multiobjective methods (Cohon 1978). It employs an explicit representation of a set of all reachable objective values. In contrast to different generating multiobjective methods, the mathematical background of the GRS approach is the linear inequalities techniques. This approach is used now at the Computing Center of the USSR Academy of Sciences in various tasks. The structure of the paper is as follows: first the mathematical background of the approach is outlined, and then possible applications of the approach to the Skane water resources management are discussed

Testing the role of screening with vocational skills: the case of post-secondary initial vocational training institutes in Greece

The paper examines whether post secondary initial vocational training acts as a filter in the private sector segment of the Greek labour market, using a sample consisting of post secondary initial vocational training graduates and secondary education graduates (control group). The results suggest that no screening is evident in the case of male employees, whereas the hypothesis of «weak» screening cannot be rejected in the case of female employees. (DIPF/Orig.

Screening of Hydrodynamic Interactions in Semidilute Polymer Solutions: A Computer Simulation Study

We study single-chain motion in semidilute solutions of polymers of length N = 1000 with excluded-volume and hydrodynamic interactions by a novel algorithm. The crossover length of the transition from Zimm (short lengths and times) to Rouse dynamics (larger scales) is proportional to the static screening length. The crossover time is the corresponding Zimm time. Our data indicate Zimm behavior at large lengths but short times. There is no hydrodynamic screening until the chains feel constraints, after which they resist the flow: "Incomplete screening" occurs in the time domain.Comment: 3 figure

Polymer-Mode-Coupling Theory of Finite-Size-Fluctuation Effects in Entangled Solutions, Melts and Gels. II. Comparison with Experiment

The predictions of the polymer mode coupling theory for the finite size corrections to the transport coefficients of entangled polymeric systems are tested in comparisons with various experimental data. It is found that quantitative descriptions of the viscosities, eta, dielectric relaxation time, tau_e, and diffusion coefficients, D, of polymer melts can be achieved with two microscopic structural fit parameters whose values are in the range expected from independent theoretical or experimental information. An explanation for the (apparent) power law behaviors of eta, taue, and D in (chemically distinct) melts for intermediate molecular weights as arising from finite size corrections, mainly the self-consistent constraint release mechanism, is given. The variation of tracer dielectric relaxation times from Rouse to reptation-like behavior upon changes of the matrix molecular weight is analyzed. Self and tracer diffusion constants of entangled polymer solutions can be explained by the theory as well, if one further parameter of the theory is adjusted. The anomalous scaling of the tracer diffusion coefficients in semidilute and concentrated polystyrene solutions, D\sim N^{-2.5}, is predicted to arise due to the spatial correlations of the entanglement constraints, termed ``constraint porosity''. Extensions of the theory to polymer tracer diffusion through polyvinylmethylether and polyacrylamide gels provide an explanation of the observation of anomalously high molecular weight scaling exponents in a range where the size of the tracer, R_g, already considerably exceeds the gel pore size, xi_g.Comment: Latex, figures and styles files included; Macromolecules, in press (1997

Sedimentation of binary mixtures of like- and oppositely charged colloids: the primitive model or effective pair potentials?

We study sedimentation equilibrium of low-salt suspensions of binary mixtures of charged colloids, both by Monte Carlo simulations of an effective colloids-only system and by Poisson-Boltzmann theory of a colloid-ion mixture. We show that the theoretically predicted lifting and layering effect, which involves the entropy of the screening ions and a spontaneous macroscopic electric field [J. Zwanikken and R. van Roij, Europhys. Lett. {\bf 71}, 480 (2005)], can also be understood on the basis of an effective colloid-only system with pairwise screened-Coulomb interactions. We consider, by theory and by simulation, both repelling like-charged colloids and attracting oppositely charged colloids, and we find a re-entrant lifting and layering phenomenon when the charge ratio of the colloids varies from large positive through zero to large negative values