Polymer dynamics in time-dependent periodic potentials

Dynamics of a discrete polymer in time-dependent external potentials is studied with the master equation approach. We consider both stochastic and deterministic switching mechanisms for the potential states and give the essential equations for computing the stationary state properties of molecules with internal structure in time-dependent periodic potentials on a lattice. As an example, we consider standard and modified Rubinstein-Duke polymers and calculate their mean drift and effective diffusion coefficient in the two-state non-symmetric flashing potential and symmetric traveling potential. Rich non-linear behavior of these observables is found. By varying the polymer length, we find current inversions caused by the rebound effect that is only present for molecules with internal structure. These results depend strongly on the polymer type. We also notice increased transport coherence for longer polymers.Comment: 22 pages, 7 figure

On-line assessment for e-learning: options and opportunities

The desire to produce educational multi-media packages of ever greater sophistication is such that other, more problematic, elements of e- or on- line learning receive less attention by academics and courseware developers alike. One such problematic area is that of assessment, which is surprising, as e-learning assessment procedures are more critical in defining the learning that takes place. However, because e-learning can create a much richer, more varied active learning experience than would normally occur via the passive didactic teaching mode currently utilised in most universities and centred on the use of the lecture, it also has the potential to provide new and innovative assessments modes and systems. The extent to which the potential of innovatory assessment is realised via e-learning depends on two factors. First, the level of computer component and interactivity utilised in elearning. Second, the attitude of academic staff towards their teaching role, and, more specifically, how they operate within an elearning environment. The speed of the development in online technologies and techniques is such that the information given here will not provide all the answers, it should, nevertheless, enable some of the correct questions to be pose

Finite-size effects in dynamics of zero-range processes

The finite-size effects prominent in zero-range processes exhibiting a condensation transition are studied by using continuous-time Monte Carlo simulations. We observe that, well above the thermodynamic critical point, both static and dynamic properties display fluid-like behavior up to a density {\rho}c (L), which is the finite-size counterpart of the critical density {\rho}c = {\rho}c (L \rightarrow \infty). We determine this density from the cross-over behavior of the average size of the largest cluster. We then show that several dynamical characteristics undergo a qualitative change at this density. In particular, the size distribution of the largest cluster at the moment of relocation, the persistence properties of the largest cluster and correlations in its motion are studied.Comment: http://pre.aps.org/abstract/PRE/v82/i3/e03111

Luonnonmukainen tuotanto tilastojen valossa

Maa- ja metsätalousministeriön asettama luomustrategiatyöryhmä linjasi vuonna 2000 tavoitteeksi, että luonnonmukaisesti viljelty peltoala olisi vähintään 10 % kokonaisviljelyalasta vuonna 2006. Jotta tämä tavoite saavutettaisiin, tulisi peltoalan kasvun jatkua noin 12 000 hehtaarin suuruisena tulevina vuosina.Vo

Development of Climate Choice Lunch concept for restaurants based on carbon footprinting

201

Variation in height and survival among northern populations of pedunculate oak (Quercus robur L.): results of a 13-year field study

201

Carbon footprint reduction potential with plant proteins at protein, product and diet level

201