199 research outputs found
Introduction to the special theme Assistive technologies for a more accessible and inclusive society
Introduction to the special theme: Assistive Technologies for a More Accessible and Inclusive Societ
Simple smart homes web interfaces for blind people
Last-decade great advances in technology have contributed to make home smarter and more comfortable, especially for people with disabilities. A lot of low cost solutions are available on the market, which can be controlled remotely by a Home Automation System (HAS). Unfortunately, the user interfaces are usually designed to be visually oriented which can exclude some user categories, like those who are blind. This paper focuses on the design of usable Web user interfaces for Home Automation Systems, with a special attention to the functions as well as the interface arrangement in order to enhance the interaction via screen reader. The proposed indications could inspire other designers to make the user experience more satisfying and effective for people who interact via screen reader
Non-gaussian effects in the cage dynamics of polymers
The correlation between the fast cage dynamics and structural relaxation is
investigated in a model polymer system. It is shown that the cage vibration
amplitude, as expressed by the Debye-Waller factor, and the relaxation time
collapse on a single universal curve with a simple analytic form
when the temperature, the density, the chain length and the monomer-monomer
interaction potential are changed. For the physical states with the same
coincidence of the mean-square displacement, the intermediate
scattering function and the non-Gaussian parameter is observed in a wide time
window spanning from the ballistic regime to the onset of the Rouse dynamics
driven by the chain connectivity. The role of the non-Gaussian effects is
discussed.Comment: 8 pages, 5 figure
A study of the deep structure of the energy landscape of glassy polystyrene: the exponential distribution of the energy-barriers revealed by high-field Electron Spin Resonance spectroscopy
The reorientation of one small paramagnetic molecule (spin probe) in glassy
polystyrene (PS) is studied by high-field Electron Spin Resonance spectroscopy
at two different Larmor frequencies (190 and 285 GHz). The exponential
distribution of the energy-barriers for the rotational motion of the spin probe
is unambigously evidenced at both 240K and 270K. The same shape for the
distribution of the energy-barriers of PS was evidenced by the master curves
provided by previous mechanical and light scattering studies. The breadth of
the energy-barriers distribution of the spin probe is in the range of the
estimates of the breadth of the PS energy-barriers distribution. The evidence
that the deep structure of the energy landscape of PS exhibits the exponential
shape of the energy-barriers distribution agrees with results from
extreme-value statistics and the trap model by Bouchaud and coworkers.Comment: Final version in press as Letter to the Editor on J.Phys.:Condensed
Matter. Changes in bol
Glassforming Liquids, Amorphous and Semicrystalline Polymers: Exploring their Energy Landscape and Dynamical Heterogeneity by Multi-frequency High-Field EPR
We review past and recent work carried out on viscous liquids, amorphous and semicrystalline polymers by multifrequency high-field electron paramagnetic resonance (HF-EPR) facility in Pisa. The emphasis is on the enhanced ability to provide fine details of the reorientation process of the paramagnetic guest, the spin probe, revealing features driving the dynamics of the host system, including the energy-barrier distribution of glassy polymers, the dynamical heterogeneity of semicrystalline polymers, and the dynamical changes occurring at the critical temperature predicted by the ideal mode-coupling theory
Fredkin Gates for Finite-valued Reversible and Conservative Logics
The basic principles and results of Conservative Logic introduced by Fredkin
and Toffoli on the basis of a seminal paper of Landauer are extended to
d-valued logics, with a special attention to three-valued logics. Different
approaches to d-valued logics are examined in order to determine some possible
universal sets of logic primitives. In particular, we consider the typical
connectives of Lukasiewicz and Godel logics, as well as Chang's MV-algebras. As
a result, some possible three-valued and d-valued universal gates are described
which realize a functionally complete set of fundamental connectives.Comment: 57 pages, 10 figures, 16 tables, 2 diagram
Anti-TNF-alpha agents and endothelial function in rheumatoid arthritis: A systematic review and meta-analysis
Rheumatoid arthritis (RA) has been associated with endothelial dysfunction, a pathophysiological feature of atherosclerosis. Our aim was to determine whether TNF-\u3b1 blockade has a beneficial effect on endothelial function in RA. We performed a systematic review with meta-analysis to evaluate the effect of anti-TNF-\u3b1 agents on endothelial function in RA patients. MedLine, Cochrane CENTRAL and SCOPUS were searched up to March 2016. Inclusion criteria were: 1) randomised controlled trial (RCT), quasi-RCT, before-after cohort study; 2) including RA patients; 3) treatment with anti-TNF-\u3b1 medications; 4) evaluating the change from baseline in endothelial function. The search strategy retrieved 180 records, of which 20 studies were included in the systematic review. Pooled analysis using a random-effects model demonstrated a significant improvement in endothelial function following anti-TNF-\u3b1 treatment (SDM 0.987, 95%CI [0.64-1.33], p < 0.0001). Generalisation of the results of the meta-analysis may be limited due to the presence of heterogeneity (I2 = 82.65%, p < 0.001) and evidence of possible publication bias. Meta-regression showed that endothelial function measurement technique was a significant contributor to heterogeneity. In conclusion, although limited by the methodological quality of the included studies, our meta-analysis suggests that anti-TNF-\u3b1 treatment may improve endothelial function in RA patients
Universal divergenceless scaling between structural relaxation and caged dynamics in glass-forming systems
On approaching the glass transition, the microscopic kinetic unit spends
increasing time rattling in the cage of the first neighbours whereas its
average escape time, the structural relaxation time , increases
from a few picoseconds up to thousands of seconds. A thorough study of the
correlation between and the rattling amplitude, expressed by the
Debye-Waller factor (DW), was carried out. Molecular-dynamics (MD) simulations
of both a model polymer system and a binary mixture were performed by varying
the temperature, the density , the potential and the polymer length to
consider the structural relaxation as well as both the rotational and the
translation diffusion. The simulations evidence the scaling between the
and the Debye-Waller factor. An analytic model of the master
curve is developed in terms of two characteristic length scales pertaining to
the distance to be covered by the kinetic unit to reach a transition state. The
model does not imply divergences. The comparison with the
experiments supports the numerical evidence over a range of relaxation times as
wide as about eighteen orders of magnitude. A comparison with other scaling and
correlation procedures is presented. The study suggests that the equilibrium
and the moderately supercooled states of the glassformers possess key
information on the huge slowing-down of their relaxation close to the glass
transition. The latter, according to the present simulations, exhibits features
consistent with the Lindemann melting criterion and the free-volume model.Comment: 8 pages, 11 figure
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