1,208 research outputs found
Predicting university performance in psychology: the role of previous performance and discipline-specific knowledge
Recent initiatives to enhance retention and widen participation ensure it is crucial to understand the factors that predict students' performance during their undergraduate degree. The present research used Structural Equation Modeling (SEM) to test three separate models that examined the extent to which British Psychology students' A-level entry qualifications predicted: (1) their performance in years 1-3 of their Psychology degree, and (2) their overall degree performance. Students' overall A-level entry qualifications positively predicted performance during their first year and overall degree performance, but negatively predicted their performance during their third year. Additionally, and more specifically, students' A-level entry qualifications in Psychology positively predicted performance in the first year only. Such findings have implications for admissions tutors, as well as for students who have not studied Psychology before but who are considering applying to do so at university
Fabrication of high quality plan-view TEM specimens using the focused ion beam
We describe a technique using a focused ion beam instrument to fabricate high quality plan-view specimens for transmission electron microscopy studies. The technique is simple, site-specific and is capable of fabricating multiple large, >100 μm2 electron transparent windows within epitaxially-grown thin films. A film of La0.67Sr0.33MnO3 is used to demonstrate the technique and its structural and functional properties are surveyed by high resolution imaging, electron spectroscopy, atomic force microscopy and Lorentz electron microscopy. The window is demonstrated to have good thickness uniformity and a low defect density that does not impair the film’s Curie temperature. The technique will enable the study of in–plane structural and functional properties of a variety of epitaxial thin film systems
Energy Dependence of the NN t-matrix in the Optical Potential for Elastic Nucleon-Nucleus Scattering
The influence of the energy dependence of the free NN t-matrix on the optical
potential of nucleon-nucleus elastic scattering is investigated within the
context of a full-folding model based on the impulse approximation. The
treatment of the pole structure of the NN t-matrix, which has to be taken into
account when integrating to negative energies is described in detail. We
calculate proton-nucleus elastic scattering observables for O,
Ca, and Pb between 65 and 200 MeV laboratory energy and study
the effect of the energy dependence of the NN t-matrix. We compare this result
with experiment and with calculations where the center-of-mass energy of the NN
t-matrix is fixed at half the projectile energy. It is found that around 200
MeV the fixed energy approximation is a very good representation of the full
calculation, however deviations occur when going to lower energies (65 MeV).Comment: 11 pages (revtex), 6 postscript figure
Kinetics of vinyl acetate emulsion polymerization in a pulsed tubular reactor: comparison between experimental and simulation results
Anomalous Dynamics of Forced Translocation
We consider the passage of long polymers of length N through a hole in a
membrane. If the process is slow, it is in principle possible to focus on the
dynamics of the number of monomers s on one side of the membrane, assuming that
the two segments are in equilibrium. The dynamics of s(t) in such a limit would
be diffusive, with a mean translocation time scaling as N^2 in the absence of a
force, and proportional to N when a force is applied. We demonstrate that the
assumption of equilibrium must break down for sufficiently long polymers (more
easily when forced), and provide lower bounds for the translocation time by
comparison to unimpeded motion of the polymer. These lower bounds exceed the
time scales calculated on the basis of equilibrium, and point to anomalous
(sub-diffusive) character of translocation dynamics. This is explicitly
verified by numerical simulations of the unforced translocation of a
self-avoiding polymer. Forced translocation times are shown to strongly depend
on the method by which the force is applied. In particular, pulling the polymer
by the end leads to much longer times than when a chemical potential difference
is applied across the membrane. The bounds in these cases grow as N^2 and
N^{1+\nu}, respectively, where \nu is the exponent that relates the scaling of
the radius of gyration to N. Our simulations demonstrate that the actual
translocation times scale in the same manner as the bounds, although influenced
by strong finite size effects which persist even for the longest polymers that
we considered (N=512).Comment: 13 pages, RevTeX4, 16 eps figure
Quantum walk on distinguishable non-interacting many-particles and indistinguishable two-particle
We present an investigation of many-particle quantum walks in systems of
non-interacting distinguishable particles. Along with a redistribution of the
many-particle density profile we show that the collective evolution of the
many-particle system resembles the single-particle quantum walk evolution when
the number of steps is greater than the number of particles in the system. For
non-uniform initial states we show that the quantum walks can be effectively
used to separate the basis states of the particle in position space and
grouping like state together. We also discuss a two-particle quantum walk on a
two- dimensional lattice and demonstrate an evolution leading to the
localization of both particles at the center of the lattice. Finally we discuss
the outcome of a quantum walk of two indistinguishable particles interacting at
some point during the evolution.Comment: 8 pages, 7 figures, To appear in special issue: "quantum walks" to be
published in Quantum Information Processin
Parity proofs of the Kochen-Specker theorem based on the 24 rays of Peres
A diagrammatic representation is given of the 24 rays of Peres that makes it
easy to pick out all the 512 parity proofs of the Kochen-Specker theorem
contained in them. The origin of this representation in the four-dimensional
geometry of the rays is pointed out.Comment: 14 pages, 6 figures and 3 tables. Three references have been added.
Minor typos have been correcte
Disordered Josephson Junctions of d-Wave Superconductors
We study the Josephson effect between weakly coupled d-wave superconductors
within the quasiclassical theory, in particular, the influence of interface
roughness on the current-phase relation and the critical current of mirror
junctions and asymmetric junctions. For mirror junctions the
temperature dependence of the critical current is non-monotonic in the limit of
low roughness, but monotonic for very rough interfaces. For
asymmetric junctions with a linear dimension much larger than the
superconducting coherence length we find a -like current-phase
relation, whereas for contacts on the scale of the coherence length or smaller
the usual -like behavior is observed. Our results compare well with
recent experimental observations.Comment: 10 pages, 12 figures; accepted for publication in Phys. Rev.
Fluctuation-dissipation relations in the non-equilibrium critical dynamics of Ising models
We investigate the relation between two-time, multi-spin, correlation and
response functions in the non-equilibrium critical dynamics of Ising models in
d=1 and d=2 spatial dimensions. In these non-equilibrium situations, the
fluctuation-dissipation theorem (FDT) is not satisfied. We find FDT
`violations' qualitatively similar to those reported in various glassy
materials, but quantitatively dependent on the chosen observable, in contrast
to the results obtained in infinite-range glass models. Nevertheless, all FDT
violations can be understood by considering separately the contributions from
large wavevectors, which are at quasi-equilibrium and obey FDT, and from small
wavevectors where a generalized FDT holds with a non-trivial limit
fluctuation-dissipation ratio X. In d=1, we get X = 1/2 for spin observables,
which measure the orientation of domains, while X = 0 for observables that are
sensitive to the domain-wall motion. Numerical simulations in d=2 reveal a
unique X = 0.34 for all observables. Measurement protocols for X are discussed
in detail. Our results suggest that the definition of an effective temperature
Teff = T / X for large length scales is generically possible in non-equilibrium
critical dynamics.Comment: 26 pages, 10 figure
Sustainable change: long-term efforts toward developing a learning organization
Globalization and intensified competition require organizations to change and adapt to dynamic environments in order to stay competitive. This article describes a longitudinal action research study supporting the strategic change of a trading company. The strategic change was accompanied by planned changes in organizational structures and processes, management systems, emerging changes in leadership, and organization members’ attitudes and behaviors, and it was supported by management development activities. Longitudinal data over a 4-year period including participant observation and interviews reveal that a systemic approach, a learning and becoming perspective toward change, trust, an appropriate role perception, and the specific use of management instruments contribute to sustained change that resulted in performance improvements and a move toward a learning organization. We conclude with implications for strategic change and suggestions for further research in this area
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