7,891 research outputs found
Coarse-graining polymers as soft colloids
We show how to coarse grain polymers in a good solvent as single particles,
interacting with density-independent or density-dependent interactions. These
interactions can be between the centres of mass, the mid-points or end-points
of the polymers. We also show how to extend these methods to polymers in poor
solvents and mixtures of polymers. Treating polymers as soft colloids can
greatly speed up the simulation of complex many-polymer systems, including
polymer-colloid mixtures.Comment: to appear in Physica A, special STATPHYS 2001 edition. Content of
invited talk by AA
Deceleration of neutral molecules in macroscopic traveling traps
A new type of decelerator is presented where polar neutral molecules are
guided and decelerated using the principle of traveling electric potential
wells, such that molecules are confined in stable three-dimensional traps
throughout. This new decelerator is superior to the best currently operational
decelerator (Scharfenberg et al., Phys.Rev.A 79, 023410(2009)), providing a
substantially larger acceptance even at higher accelerations. The mode of
operation is described and experimentally demonstrated by guiding and
decelerating CO molecules.Comment: 10 pages, 3 figure
How global is international CSR research? Insights and recommendations from a systematic review
A trial studying approach to predict college achievement
We argue that using trial studying is a reliable and valid way to select students for higher education. This method is based on a work sample approach often used in personnel selection contexts. We discuss that this method has predictive validity for study success, has high acceptance by stakeholders, and measures self-regulation in a high-stakes testing context that cannot be measured through self-report questionnaires. We suggest further research to implement this method to select students
A traveling wave decelerator for neutral polar molecules
Recently, a decelerator for neutral polar molecules has been presented that
operates on the basis of macroscopic, three-dimensional, traveling
electrostatic traps (Osterwalder et al., Phys. Rev. A 81, 051401 (2010)). In
the present paper, a complete description of this decelerator is given, with
emphasis on the electronics and the mechanical design. Experimental results
showing the transverse velocity distributions of guided molecules are shown and
compared to trajectory simulations. An assessment of non-adiabatic losses is
made by comparing the deceleration signals from 13-CO with those from 12-CO and
with simulated signals.Comment: 10 pages, 7 figure
Stability of Colloidal Quasicrystals
Freezing of charge-stabilized colloidal suspensions and relative stabilities
of crystals and quasicrystals are studied using thermodynamic perturbation
theory. Macroion interactions are modelled by effective pair potentials
combining electrostatic repulsion with polymer-depletion or van der Waals
attraction. Comparing free energies -- counterion terms included -- for
elementary crystals and rational approximants to icosahedral quasicrystals,
parameters are identified for which one-component quasicrystals are stabilized
by a compromise between packing entropy and cohesive energy.Comment: 6 pages, 4 figure
Can Polymer Coils be modeled as "Soft Colloids"?
We map dilute or semi-dilute solutions of non-intersecting polymer chains
onto a fluid of ``soft'' particles interacting via a concentration dependent
effective pair potential, by inverting the pair distribution function of the
centers of mass of the initial polymer chains. A similar inversion is used to
derive an effective wall-polymer potential; these potentials are combined to
successfully reproduce the calculated exact depletion interaction induced by
non-intersecting polymers between two walls. The mapping opens up the
possibility of large-scale simulations of polymer solutions in complex
geometries.Comment: 4 pages, 3 figures ReVTeX[epsfig,multicol,amssymb] references update
Asymptotics and zeros of Sobolev orthogonal polynomials on unbounded supports
In this paper we present a survey about analytic properties of polynomials
orthogonal with respect to a weighted Sobolev inner product such that the
vector of measures has an unbounded support. In particular, we are focused in
the study of the asymptotic behaviour of such polynomials as well as in the
distribution of their zeros. Some open problems as well as some new directions
for a future research are formulated.Comment: Changed content; 34 pages, 41 reference
Implementing evidence-based assessment and selection in organizations:A review and an agenda for future research
In personnel- and educational selection, a substantial gap exists between research and practice, since evidence-based assessment instruments and decision-making procedures are underutilized. We provide an overview of studies that investigated interventions to encourage the use of evidence-based assessment methods, or factors related to their use. The most promising studies were grounded in self-determination theory. Training and autonomy in the design of evidence-based assessment methods were positively related to their use, while negative stakeholder perceptions decreased practitioners’ intentions to use evidence-based assessment methods. Use of evidence-based decision-making procedures was positively related to access to such procedures, information to use it, and autonomy over the procedure, but negatively related to receiving outcome feedback. A review of the professional selection literature showed that the implementation of evidence-based assessment was hardly discussed. We conclude with an agenda for future research on encouraging evidence-based assessment practice
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