1,402 research outputs found
One-year efficacy and safety of single or one to three weekly injections of hylan G-F 20 for knee osteoarthritis: a systematic literature review and meta-analysis
Development and Evaluation of a Positive Youth Development Course for University Students in Hong Kong
With higher education, university graduates are important elements of the labor force in knowledge-based economies. With reference to the mental health and developmental problems in university students, there is a need to review university's role in nurturing holistic development of students. Based on the positive youth development approach, it is argued that promoting intrapersonal competencies is an important strategy to facilitate holistic development of young people in Hong Kong. In The Hong Kong Polytechnic University, a course entitled Tomorrow's Leader focusing on positive youth development constructs to promote student well-being will be offered on a compulsory basis starting from 2012/13 academic year under the new undergraduate curriculum structure. The proposed course was piloted in 2010/11 school year. Different evaluation strategies, including objective outcome evaluation, subjective outcome evaluation, process evaluation, and qualitative evaluation, are being carried out to evaluate the developed course. Preliminary evaluation findings based on the piloting experience in 2010/11 academic year are presented in this paper
Kinetically driven glassy transition in an exactly solvable toy model with reversible mode coupling mechanism and trivial statics
We propose a toy model with reversible mode coupling mechanism and with
trivial Hamiltonian (and hence trivial statics). The model can be analyzed
exactly without relying upon uncontrolled approximation such as the
factorization approximation employed in the current MCT. We show that the model
exhibits a kinetically driven transition from an ergodic phase to nonergodic
phase. The nonergodic state is the nonequilibrium stationary solution of the
Fokker-Planck equation for the distribution function of the modelComment: 10 pages, 1 figure, contribution to the Proceedings of the Barcelona
Workshop 'Glassy Behavior of Kinetically Constrained Models'. To appear in J.
Phys. Condens. Matte
Intelligent Financial Fraud Detection Practices: An Investigation
Financial fraud is an issue with far reaching consequences in the finance
industry, government, corporate sectors, and for ordinary consumers. Increasing
dependence on new technologies such as cloud and mobile computing in recent
years has compounded the problem. Traditional methods of detection involve
extensive use of auditing, where a trained individual manually observes reports
or transactions in an attempt to discover fraudulent behaviour. This method is
not only time consuming, expensive and inaccurate, but in the age of big data
it is also impractical. Not surprisingly, financial institutions have turned to
automated processes using statistical and computational methods. This paper
presents a comprehensive investigation on financial fraud detection practices
using such data mining methods, with a particular focus on computational
intelligence-based techniques. Classification of the practices based on key
aspects such as detection algorithm used, fraud type investigated, and success
rate have been covered. Issues and challenges associated with the current
practices and potential future direction of research have also been identified.Comment: Proceedings of the 10th International Conference on Security and
Privacy in Communication Networks (SecureComm 2014
Non exponential relaxation in fully frustrated models
We study the dynamical properties of the fully frustrated Ising model. Due to
the absence of disorder the model, contrary to spin glass, does not exhibit any
Griffiths phase, which has been associated to non-exponential relaxation
dynamics. Nevertheless we find numerically that the model exhibits a stretched
exponential behavior below a temperature T_p corresponding to the percolation
transition of the Kasteleyn-Fortuin clusters. We have also found that the
critical behavior of this clusters for a fully frustrated q-state spin model at
the percolation threshold is strongly affected by frustration. In fact while in
absence of frustration the q=1 limit gives random percolation, in presence of
frustration the critical behavior is in the same universality class of the
ferromagnetic q=1/2-state Potts model.Comment: 7 pages, RevTeX, 11 figs, to appear on Physical Review
Broadband Dielectric Spectroscopy on Glass-Forming Propylene Carbonate
Dielectric spectroscopy covering more than 18 decades of frequency has been
performed on propylene carbonate in its liquid and supercooled-liquid state.
Using quasi-optic submillimeter and far-infrared spectroscopy the dielectric
response was investigated up to frequencies well into the microscopic regime.
We discuss the alpha-process whose characteristic timescale is observed over 14
decades of frequency and the excess wing showing up at frequencies some three
decades above the peak frequency. Special attention is given to the
high-frequency response of the dielectric loss in the crossover regime between
alpha-peak and boson-peak. Similar to our previous results in other glass
forming materials we find evidence for additional processes in the crossover
regime. However, significant differences concerning the spectral form at high
frequencies are found. We compare our results to the susceptibilities obtained
from light scattering and to the predictions of various models of the glass
transition.Comment: 13 pages, 9 figures, submitted to Phys. Rev.
Evidence of coexistence of change of caged dynamics at Tg and the dynamic transition at Td in solvated proteins
Mossbauer spectroscopy and neutron scattering measurements on proteins
embedded in solvents including water and aqueous mixtures have emphasized the
observation of the distinctive temperature dependence of the atomic mean square
displacements, , commonly referred to as the dynamic transition at some
temperature Td. At low temperatures, increases slowly, but it assume
stronger temperature dependence after crossing Td, which depends on the
time/frequency resolution of the spectrometer. Various authors have made
connection of the dynamics of solvated proteins including the dynamic
transition to that of glass-forming substances. Notwithstanding, no connection
is made to the similar change of temperature dependence of obtained by
quasielastic neutron scattering when crossing the glass transition temperature
Tg, generally observed in inorganic, organic and polymeric glass-formers.
Evidences are presented to show that such change of the temperature dependence
of from neutron scattering at Tg is present in hydrated or solvated
proteins, as well as in the solvents used unsurprisingly since the latter is
just another organic glass-formers. The obtained by neutron scattering at
not so low temperatures has contributions from the dissipation of molecules
while caged by the anharmonic intermolecular potential at times before
dissolution of cages by the onset of the Johari-Goldstein beta-relaxation. The
universal change of at Tg of glass-formers had been rationalized by
sensitivity to change in volume and entropy of the beta-relaxation, which is
passed onto the dissipation of the caged molecules and its contribution to
. The same rationalization applies to hydrated and solvated proteins for
the observed change of at Tg.Comment: 28 pages, 10 figures, 1 Tabl
Dynamic Mean-Field Glass Model with Reversible Mode Coupling and Trivial Hamiltonian
Often the current mode coupling theory (MCT) of glass transitions is compared
with mean field theories. We explore this possible correspondence. After
showing a simple-minded derivation of MCT with some difficulties we give a
concise account of our toy model developed to gain more insight into MCT. We
then reduce this toy model by adiabatically eliminating rapidly varying
velocity-like variables to obtain a Fokker-Planck equation for the slowly
varying density-like variables where diffusion matrix can be singular. This
gives a room for nonergodic stationary solutions of the above equation.Comment: 9 pages, contribution to the Proceedings of the Merida Satellite
Meeting to STATPHYS21 (Merida, Mexico, July 9-14, 2001). To appear in J.
Phys. Condens. Matte
The relationship between fragility, configurational entropy and the potential energy landscape of glass forming liquids
Glass is a microscopically disordered, solid form of matter that results when
a fluid is cooled or compressed in such a fashion that it does not crystallise.
Almost all types of materials are capable of glass formation -- polymers, metal
alloys, and molten salts, to name a few. Given such diversity, organising
principles which systematise data concerning glass formation are invaluable.
One such principle is the classification of glass formers according to their
fragility\cite{fragility}. Fragility measures the rapidity with which a
liquid's properties such as viscosity change as the glassy state is approached.
Although the relationship between features of the energy landscape of a glass
former, its configurational entropy and fragility have been analysed previously
(e. g.,\cite{speedyfr}), an understanding of the origins of fragility in these
features is far from being well established. Results for a model liquid, whose
fragility depends on its bulk density, are presented in this letter. Analysis
of the relationship between fragility and quantitative measures of the energy
landscape (the complicated dependence of energy on configuration) reveal that
the fragility depends on changes in the vibrational properties of individual
energy basins, in addition to the total number of such basins present, and
their spread in energy. A thermodynamic expression for fragility is derived,
which is in quantitative agreement with {\it kinetic} fragilities obtained from
the liquid's diffusivity.Comment: 8 pages, 3 figure
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