A framework for accessible m-government implementation

The great popularity and rapid diffusion of mobile technologies at worldwide level has also been recognised by the public sector, leading to the creation of m-government. A major challenge for m-government is accessibility – the provision of an equal service to all citizens irrespective of their psychical, mental or technical capabilities. This paper sketches the profiles of six citizen groups: Visually Impaired, Hearing Impaired, Motor Impaired, Speech Impaired, Cognitive Impaired and Elderly. M-government examples that target the aforementioned groups are discussed and a framework for accessible m-government implementation with reference to the W3C Mobile Web Best Practices is proposed

Triple photoionization of Lithium near threshold

Solving the full classical four-body Coulomb problem numerically using a Wigner initial distribution we formulate a classical-quantum hybrid approach to study triple ionization by single photon absorption from the Li ground state in the threshold region. We confirm the Wannier threshold law $\sigma \propto E^{\alpha}$ and we show that the $\alpha$ determined in the interval between 2-5 eV deviates from the analytical threshold value of 2.16 which we find in the interval between $0.1-2$ eV.Comment: 6 pages, 3 figure

Controlling electron-electron correlation in frustrated double ionization of molecules with orthogonally polarized two-color laser fields

We demonstrate the control of electron-electron correlation in frustrated double ionization (FDI) of the two-electron triatomic molecule D$_{3}^{+}$ when driven by two orthogonally polarized two-color laser fields. We employ a three-dimensional semi-classical model that fully accounts for the electron and nuclear motion in strong fields. We analyze the FDI probability and the distribution of the momentum of the escaping electron along the polarization direction of the longer wavelength and more intense laser field. These observables when considered in conjunction bear clear signatures of the prevalence or absence of electron-electron correlation in FDI, depending on the time-delay between the two laser pulses. We find that D$_{3}^{+}$ is a better candidate compared to H$_{2}$ for demonstrating also experimentally that electron-electron correlation indeed underlies FDI.Comment: 5 pages, 4 figure

Initial state dependence in multi-electron threshold ionization of atoms

It is shown that the geometry of multi-electron threshold ionization in atoms depends on the initial configuration of bound electrons. The reason for this behavior is found in the stability properties of the classical fixed point of the equations of motion for multiple threshold fragmentation. Specifically for three-electron break-up, apart from the symmetric triangular configuration also a break-up of lower symmetry in the form of a T-shape can occur, as we demonstrate by calculating triple photoionization for the lithium ground and first excited states. We predict the electron break-up geometry for threshold fragmentation experiments

Slingshot non-sequential double ionization as a gate to anti-correlated two electron escape

At intensities below-the-recollision threshold, we show that re-collision-induced excitation with one electron escaping fast after re-collision and the other electron escaping with a time delay via a Coulomb slingshot motion is one of the most important mechanisms of non-sequential double ionization, for strongly-driven He at 400 nm. Slingshot-NSDI is a general mechanism present for a wide range of low intensities and pulse durations. Anti-correlated two-electron escape is its striking hallmark. This mechanism offers an alternative explanation of anti-correlated two-electron escape obtained in previous studies.Comment: 6 pages, 3 figure

The Coulomb four-body problem in a classical framework: Triple photoionization of lithium

Formulating a quasiclassical approach we determine the cross section for the complete four-body break-up of the lithium ground state following single photon absorption from threshold up to 220 eV excess energy. In addition, we develop a new classification scheme for three-electron ionizing trajectories in terms of electron-electron collisions, thereby identifying two main ionization paths which the three electrons in the ground state of lithium follow to escape to the continuum. The dominant escape paths manifest themselves in a characteristic ``T-shape'' break-up pattern of the three electrons which implies observable structures in the electronic angular correlation probability. This break-up pattern prevails for excess energies so low that the Wannier threshold law $\sigma\propto E^{\alpha}$ describes already the triple ionization cross section, whose predicted value $\alpha=2.16$ we can confirm quantitatively

HAMSTRINGS COACTIVATION IN TRAINED LONG JUMPERS AND UNTRAINED INDIVIDUALS DURING DROP JUMPING

The purpose of this study was to examine the EMG activity patterns of the hamstrings during drop jumping from different heights in trained longer jumpers and controls. A group of trained long jumpers and a group of untrained subjects performed maximal drop jumps from 20cm, 40cm and 60 cm on a force platform. The surface EMG activity of the hamstrings was recorded using bipolar electrodes. The ground reaction forces (GRF) and 3-D kinematic data were also recorded. Two-way analysis of variance tests indicated non-significant differences in hamstring EMG amplitude between trained and untrained athletes. However, the long jumpers had significantly higher vertical GRF values and some kinematic differences compared to untrained individuals. The absence of higher hamstrings activity in the long jumpers may have been a contributing factor in their higher performance compared to controls. However, the same result indicates that this increased performance may be accompanied by a possible increased risk of knee joint instability

Non-sequential double ionization with near-single cycle laser pulses

A three-dimensional semiclassical model is used to study double ionization of Ar when driven by a near-infrared and near-single-cycle laser pulse for intensities ranging from 0.85 x 10(14) W/cm(2) to 5 x 10(14) W/cm(2). Asymmetry parameters, distributions of the sum of the two electron momentum components along the direction of the polarization of the laser field and correlated electron momenta are computed as a function of the intensity and of the carrier envelope phase. A very good agreement is found with recently obtained results in kinematically complete experiments employing near-single-cycle laser pulses. Moreover, the contribution of the direct and delayed pathways of double ionization is investigated for the above observables. Finally, an experimentally obtained anti-correlation momentum pattern at higher intensities is reproduced with the three-dimensional semiclassical model and shown to be due to a transition from strong to soft recollisions with increasing intensity