375 research outputs found
Developing A Modular Web based System for Special Education: Advantages and Challenges
AbstractThe increasing complexity of regulations governing and tracking the special education process made it ever more difficult for all parties which may be special education centers (SECs), individuals, educators, parents, government and healthcare centers. Since there are many difficulties in the management of special education, SECs cannot easily process their essence aim. In this manner, information technologies help these parties to participate equally for managing special education. Modular web based systems are one of the information technology solutions to overcome these problems. In this paper, the goal is to show the fundamental advantages and also discuss the challenges in developing such a modular web based system for special education. If the advantages of the system can be understood and the challenges of the system can be properly addressed, the development of a modular web based system for special education, in our opinion, can be promoted significantly.Selection and peer review under responsibility of Prof. Dr. Hafize Keser
Composite Polarons in Ferromagnetic Narrow-band Metallic Manganese Oxides
A new mechanism is proposed to explain the colossal magnetoresistance and
related phenomena. Moving electrons accompanied by Jahn-Teller phonon and
spin-wave clouds may form composite polarons in ferromagnetic narrow-band
manganites. The ground-state and finite-temperature properties of such
composite polarons are studied in the present paper. By using a variational
method, it is shown that the energy of the system at zero temperature decreases
with the formation of composite polaron; the energy spectrum and effective mass
of the composite polaron at finite temperature is found to be strongly
renormalized by the temperature and the magnetic field. It is suggested that
the composite polaron contribute significantly to the transport and the
thermodynamic properties in ferromagnetic narrow-band metallic manganese
oxides.Comment: Latex, no figur
Oral health and related factors in a group of children with cystic fibrosis in Istanbul, Turkey
Background: Cystic fibrosis (CF) patients can be considered as high caries risk patients because they frequently consume sugar.rich food between meals and they have a high intake of sugar containing syrups, aerosols, and salivary flow reducing medication. Variable caries prevalences were reported in CF patients in previous studies. There are no studies related to CF and salivary thromboplastic activity, which can be presented as a marker of wound healing and bleeding tendency of oral cavity.Objective: The aim of this study was to compare oral health status and salivary pH, flow rate, and thromboplastic activity in children with CF and healthy controls.Materials and Methods: Asample of 35 children with CF (23 girls and 12 boys), and 12 healthy control subjects (6 girls and 6 boys) were selected. Caries experience, oral hygiene, and dental erosion were assessed. Salivary flow rate, pH, thromboplastic activity, and total protein content were determined. Differences between the groups were evaluated using Chi.square test with a significance level set at 0.05.Results: The differences between children with CF and healthy controls in tooth brushing frequency, use of fluoride tablets, caries experience, dental erosion index, oral hygiene index, salivary flow rate and total protein levels were not statistically significant (P > 0.05). Salivary thromboplastic activity of the CF group was significantly lower than the healthy controls (P < 0.01).Conclusion: Large population studies may be necessary to establish the role of salivary thromboplastic activity in children with CF considering our findings related to the decreased salivary thromboplastic activity, which may indicate delayed oral wound healing process.Key words: Caries, children, cystic fibrosis, saliva, salivary thromboplastic activit
A single hollow beam optical trap for cold atoms
We present an optical trap for atoms that we have developed for precision
spectroscopy measurements. Cold atoms are captured in a dark region of space
inside a blue-detuned hollow laser beam formed by an axicon. We analyze the
light potential in a ray optics picture and experimentally demonstrate trapping
of laser-cooled metastable xenon atoms.Comment: 12 pages, 8 figure
Quadrupole and Hexadecapole Correlations in Rotating Nuclei Studied within the Single-j Shell Model
The influence of quadrupole and hexadecapole residual interactions on
rotational bands is investigated in a single-j shell model. An exact
shell-model diagonalization of quadrupole-plus-hexadecapole interaction can
sometimes produce a staggering of energy levels in the yrast bands.Comment: 15 pages, 9 Postscript figures, REVTEX, to be published in PR
Transition energy and lifetime for the ground state hyperfine splitting of high Z lithiumlike ions
The ground state hyperfine splitting values and the transition probabilities
between the hyperfine structure components of high Z lithiumlike ions are
calculated in the range . The relativistic, nuclear, QED and
interelectronic interaction corrections are taken into account. It is found
that the Bohr-Weisskopf effect can be eliminated in a combination of the
hyperfine splitting values of the hydrogenlike and lithiumlike ions of an
isotope. This gives a possibility for testing the QED effects in a combination
of the strong electric and magnetic fields of the heavy nucleus. Using the
experimental result for the hyperfine splitting in ^{209}Bi^{82+}, the 2s
hyperfine splitting in ^{209}Bi^{80+} is calculated to be \Delta E=0.7969(2)
eV.Comment: The nuclear charge distribution correction \delta is corrected, 14
pages, Late
A robust Logistics-Electric framework for optimal power management of electrified ports under uncertain vessel arrival time
\ua9 2024Maritime transport is responsible for producing a considerable amount of environmental pollution due to the reliance of ports and ships on the carbon-based energy sources. With the increasing trend towards port electrification to reduce carbon emissions, the operation of ports will be increasingly relying on the electricity network. This interconnection creates multiple challenges due to the complexity of power flow in the port network, uncertainty of vessel arrival time and fluctuation of power generation of renewable energy sources. These uncertainties can lead to an overload in electricity networks and delays in cargo-handling activities, resulting in increased vessel handling times and environmental emissions. This paper presents a joint logistics-electric framework for optimal operation and power management of electrified ports, considering multiple uncertainties in the arrival time of vessels, network demand, and renewable power generation. An optimal power flow method is developed for a real-life port, with consideration for multiple port logistic assets such as cargo handling equipment, reefers, and renewable energy sources. The proposed model ensures feasible port operation for all uncertainty realisations defined by robust optimisation, while minimising operational costs. Simulation results demonstrate that the probability of a network constraint violation can be as high as 70% for an electrified major UK port if the uncertainty in the port operation is neglected, presenting an unacceptable risk of disruption to port activities. Furthermore, such uncertainty can cause 150% increase in emissions if the ships use their auxiliary engine instead of using shore power. The numerical study shows that such challenges can be handled by a 0.3% increase in the robustness in face of uncertainty, while the cost increase in the worst case does not exceed 4.7%. This shows the effectiveness of the proposed method enhancing robustness against uncertainty at the minimum cost
Atomic Transport in Dense, Multi-Component Metallic Liquids
Pd43Ni10Cu27P0 has been investigated in its equilibrium liquid state with
incoherent, inelastic neutron scattering. As compared to simple liquids, liquid
PdNiCuP is characterized by a dense packing with a packing fraction above 0.5.
The intermediate scattering function exhibits a fast relaxation process that
precedes structural relaxation. Structural relaxation obeys a time-temperature
superposition that extends over a temperature range of 540K. The mode-coupling
theory of the liquid to glass transition (MCT) gives a consistent description
of the dynamics which governs the mass transport in liquid PdNiCuP alloys. MCT
scaling laws extrapolate to a critical temperature Tc at about 20% below the
liquidus temperature. Diffusivities derived from the mean relaxation times
compare well with Co diffusivities from recent tracer diffusion measurements
and diffsuivities calculated from viscosity via the Stokes-Einstein relation.
In contrast to simple metallic liquids, the atomic transport in dense, liquid
PdNiCuP is characterized by a drastical slowing down of dynamics on cooling, a
q^{-2} dependence of the mean relaxation times at intermediate q and a
vanishing isotope effect as a result of a highly collective transport
mechanism. At temperatures as high as 2Tc diffusion in liquid PdNiCuP is as
fast as in simple liquids at the melting point. However, the difference in the
underlying atomic transport mechanism indicates that the diffusion mechanism in
liquids is not controlled by the value of the diffusivity but rather by that of
the packing fraction
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