3,459 research outputs found
Personalisation of intelligent homecare services adapted to children with motor impairments
Ambient Intelligence could support innovative application domains like motor impairments' detection at the home environment. This research aims to prevent neurodevelopmental disorders through the natural interaction of the children with embedded intelligence daily life objects, like home furniture and toys. Designed system uses an interoperable platform to provide two intelligent interrelated home healthcare services: monitoring of children¿s abilities and completion of early stimulation activities. A set of sensors, which are embedded within the rooms, toys and furniture, allows private data gathering about the child's interaction with the environment. This information feeds a reasoning subsystem, which encloses an ontology of neurodevelopment items, and adapts the service to the age and acquisition of expected abilities. Next, the platform proposes customized stimulation services by taking advantage of the existing facilities at the child's environment. The result integrates Embedded Sensor Systems for Health at Mälardalen University with UPM Smart Home, for adapted services delivery
Electroactive Polyhydroquinone Coatings for Marine Fouling Prevention—A Rejected Dynamic pH Hypothesis and a Deceiving Artifact in Electrochemical Antifouling Testing
Nanometer-thin coatings of polyhydroquinone (PHQ), which release and absorb protons upon oxidation and reduction, respectively, were tested for electrochemically induced anti-biofouling activity under the hypothesis that a dynamic pH environment would discourage fouling. Antifouling tests in artificial seawater using the marine, biofilm-forming bacterium Vibrio alginolyticus proved the coatings to be ineffective in fouling prevention but revealed a deceiving artifact from the reactive species generated at the counter electrode (CE), even for electrochemical bias potentials as low as |400| mV versus Ag|AgCl. These findings provide valuable information on the preparation of nanothin PHQ coatings and their electrochemical behavior in artificial seawater. The results further demonstrate that it is critical to isolate the CE in electrochemical anti-biofouling testing
Computing the local field potential (LFP) from integrate-and-fire network models
Leaky integrate-and-fire (LIF) network models are commonly used to study how the spiking dynamics of neural networks changes with stimuli, tasks or dynamic network states. However, neurophysiological studies in vivo often rather measure the mass activity of neuronal microcircuits with the local field potential (LFP). Given that LFPs are generated by spatially separated currents across the neuronal membrane, they cannot be computed directly from quantities defined in models of point-like LIF neurons. Here, we explore the best approximation for predicting the LFP based on standard output from point-neuron LIF networks. To search for this best "LFP proxy", we compared LFP predictions from candidate proxies based on LIF network output (e.g, firing rates, membrane potentials, synaptic currents) with "ground-truth" LFP obtained when the LIF network synaptic input currents were injected into an analogous three-dimensional (3D) network model of multi-compartmental neurons with realistic morphology, spatial distributions of somata and synapses. We found that a specific fixed linear combination of the LIF synaptic currents provided an accurate LFP proxy, accounting for most of the variance of the LFP time course observed in the 3D network for all recording locations. This proxy performed well over a broad set of conditions, including substantial variations of the neuronal morphologies. Our results provide a simple formula for estimating the time course of the LFP from LIF network simulations in cases where a single pyramidal population dominates the LFP generation, and thereby facilitate quantitative comparison between computational models and experimental LFP recordings in vivo
Structural and magnetic properties of MSr2Y1.5Ce0.5Cu2Oz (M-1222) compounds with M = Fe and Co
MSr2Y1.5Ce0.5Cu2Oz (M-1222) compounds, with M = Fe and Co, have been
synthesized through a solid-state reaction route. Both compounds crystallize in
a tetragonal structure (space group I4/mmm). A Rietveld structural refinement
of room-temperature neutron diffraction data for Fe-1222 reveals that nearly
half the Fe remains at the M site, while the other half goes to the Cu site in
the CuO2 planes. Existence of Fe at two different lattice sites, is also
confirmed by 57Fe Mossbauer spectroscopy from which it is inferred that nearly
50% of the total Fe occupies the Cu site in the CuO2 planes as Fe3+, whereas
the other 50 % is located at the M site with nearly 40 % as Fe4+ and around 10%
as Fe3+. For the M = Co compound, nearly 84 % of Co remains at its designated M
site, while the rest occupies the Cu site in the CuO2 planes. The oxygen
content, z, based on oxygen occupancies refined from the neutron diffraction
data, comes close to 9.0 for both the samples The ZFC and FC magnetization
curves as a function of temperature show a complex behavior for both Fe-1222
and Co-1222 compounds.Comment: MMM Inter mag Proceedings, accepted in J. Appl. Phy
Microscopic Origin of Quantum Chaos in Rotational Damping
The rotational spectrum of Yb is calculated diagonalizing different
effective interactions within the basis of unperturbed rotational bands
provided by the cranked shell model. A transition between order and chaos
taking place in the energy region between 1 and 2 MeV above the yrast line is
observed, associated with the onset of rotational damping. It can be related to
the higher multipole components of the force acting among the unperturbed
rotational bands.Comment: 7 pages, plain TEX, YITP/K-99
Curie temperature enhancement of electron doped SrFeMoO perovskites studied by photoemission spectroscopy
We report here on the electronic structure of electron-doped half-metallic
ferromagnetic perovskites such SrLaFeMoO (=0-0.6) as
obtained from high-resolved valence-band photoemission spectroscopy (PES). By
comparing the PES spectra with band structure calculations, a distinctive peak
at the Fermi level (E) with predominantly (Fe+Mo) t
character has been evidenced for all samples, irrespectively of the values
investigated. Moreover, we show that the electron doping due to the La
substitution provides selectively delocalized carriers to the
t metallic spin channel. Consequently, a gradual rising of
the density of states at the E has been observed as a function of the La
doping. By changing the incoming photon energy we have shown that electron
doping mainly rises the density of states of Mo parentage. These findings
provide fundamental clues for understanding the origin of ferromagnetism in
these oxides and shall be of relevance for tailoring oxides having still higher
T
Bonn Potential and Shell-Model Calculations for 206,205,204Pb
The structure of the nuclei 206,205,204Pb is studied interms of shell model
employing a realistic effective interaction derived from the Bonn A
nucleon-nucleon potential. The energy spectra, binding energies and
electromagnetic properties are calculated and compared with experiment. A very
good overall agreement is obtained. This evidences the reliability of our
realistic effective interaction and encourages use of modern realistic
potentials in shell-model calculations for heavy-mass nuclei.Comment: 4 pages, 4 figures, submitted to Physical Review
Antimatter and Matter Production in Heavy Ion Collisions at CERN (The NEWMASS Experiment NA52)
Besides the dedicated search for strangelets NA52 measures light
(anti)particle and (anti)nuclei production over a wide range of rapidity.
Compared to previous runs the statistics has been increased in the 1998 run by
more than one order of magnitude for negatively charged objects at different
spectrometer rigidities. Together with previous data taking at a rigidity of
-20 GeV/c we obtained 10^6 antiprotons 10^3 antideuterons and two antihelium3
without centrality requirements. We measured nuclei and antinuclei
(p,d,antiprotons, antideuterons) near midrapidity covering an impact parameter
range of b=2-12 fm. Our results strongly indicate that nuclei and antinuclei
are mainly produced via the coalescence mechanism. However the centrality
dependence of the antibaryon to baryon ratios show that antibaryons are
diminished due to annihilation and breakup reactions in the hadron dense
environment. The volume of the particle source extracted from coalescence
models agrees with results from pion interferometry for an expanding source.
The chemical and thermal freeze-out of nuclei and antinuclei appear to coincide
with each other and with the thermal freeze-out of hadrons.Comment: 12 pages, 8 figures, to appear in the proceedings of the conference
on 'Fundamental Issues in Elementary Matter' Bad Honnef, Germany, Sept.
25-29, 200
Electronic and Magnetic Structures of Sr2FeMoO6
We have investigated the electronic and magnetic structures of Sr2FeMoO6
employing site-specific direct probes, namely x-ray absorption spectroscopy
with linearly and circularly polarized photons. In contrast to some previous
suggestions, the results clearly establish that Fe is in the formal trivalent
state in this compound. With the help of circularly polarized light, it is
unambiguously shown that the moment at the Mo sites is below the limit of
detection (< 0.25mu_B), resolving a previous controversy. We also show that the
decrease of the observed moment in magnetization measurements from the
theoretically expected value is driven by the presence of mis-site disorder
between Fe and Mo sites.Comment: To appear in Physical Review Letter
Structural and Magnetic Properties of MrSr₂Y₁.₅Ce₀.₅Cu₂Oz (M-1222) Compounds with M = Fe and Co
The MSr2Y1.5Ce0.5Cu2Oz (M-1222) compounds, with M = Fe and Co, have been synthesized through a solid-state reaction route. Both compounds crystallize in a tetragonal structure (space group 14/mmm). A Rietveld structural refinement of the room-temperature neutron diffraction data for Fe-1222 reveals that nearly half the Fe remains at the M site, while the other half goes to the Cu site in the CuO2 planes. Existence of Fe at two different lattice sites is also confirmed by 57Fe Mössbauer spectroscopy from which it is inferred that ~50% of the total Fe occupies the Cu site in the CuO2 planes as Fe3+, whereas the other ~50% is located at the M site with ~40% as Fe4+ and ~10% as Fe3+. For the M[Double Bond]Co compound, nearly 84% of Co remains at its designated M site, while the rest occupies the Cu site in the CuO2 planes
- …