1,200 research outputs found
A model for trustworthy orchestration in the internet of things
Embedded systems such as Cyber-Physical Systems (CPS) are typically designed as a network of multiple interacting elements with physical input (or sensors) and output (or actuators). One aspect of interest of open systems is fidelity, or the compliance between physical figures of interest and their internal representation. High fidelity is defined as a stable mapping between actions in the physical domain and intended or expected values in the system domain and deviations from fidelity are quantifiable over time by some appropriate informative variable. In this paper, we provide a model for designing such systems based on a framework for trustworthiness monitoring and we provide a Jason implementation to evaluate the feasibility of our approach. In particular, we build a bridge between a standard publish/subscribe framework for CPS called MQTT and Jason to enable automatic reasoning about trustworthines
Quasiclassical approach to the spin-Hall effect in the two-dimensional electron gas
We study the spin-charge coupled transport in a two-dimensional electron
system using the method of quasiclassical (-integrated) Green's functions.
In particular we derive the Eilenberger equation in the presence of a generic
spin-orbit field. The method allows us to study spin and charge transport from
ballistic to diffusive regimes and continuity equations for spin and charge are
automatically incorporated. In the clean limit we establish the connection
between the spin-Hall conductivity and the Berry phase in momentum space. For
finite systems we solve the Eilenberger equation numerically for the special
case of the Rashba spin-orbit coupling and a two-terminal geometry. In
particular, we calculate explicitly the spin-Hall induced spin polarization in
the corners, predicted by Mishchenko et al. [13]. Furthermore we find universal
spin currents in the short-time dynamics after switching on the voltage across
the sample, and calculate the corresponding spin-Hall polarization at the
edges. Where available, we find perfect agreement with analytical results.Comment: 9 pages, 6 figure
Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities
The current-induced spin polarization and momentum-dependent spin-orbit field
were measured in InGaAs epilayers with varying indium
concentrations and silicon doping densities. Samples with higher indium
concentrations and carrier concentrations and lower mobilities were found to
have larger electrical spin generation efficiencies. Furthermore,
current-induced spin polarization was detected in GaAs epilayers despite the
absence of measurable spin-orbit fields, indicating that the extrinsic
contributions to the spin polarization mechanism must be considered.
Theoretical calculations based on a model that includes extrinsic contributions
to the spin dephasing and the spin Hall effect, in addition to the intrinsic
Rashba and Dresselhaus spin-orbit coupling, are found to qualitatively agree
with the experimental results.Comment: 16 pages, 8 figure
Non-Abelian gauge fields in the gradient expansion: generalized Boltzmann and Eilenberger equations
We present a microscopic derivation of the generalized Boltzmann and
Eilenberger equations in the presence of non-Abelian gauges, for the case of a
non-relativistic disordered Fermi gas. A unified and symmetric treatment of the
charge and spin degrees of freedom is achieved. Within this
framework, just as the Lorentz force generates the Hall effect, so does
its counterpart give rise to the spin Hall effect. Considering elastic
and spin-independent disorder we obtain diffusion equations for charge and spin
densities and show how the interplay between an in-plane magnetic field and a
time dependent Rashba term generates in-plane charge currents.Comment: 11 pages, 1 figure; some corrections and updated/extended reference
Multiparametric advanced research tool for meteo satellites data interfacing with space observation of ultra high energy cosmic rays
To approach the study of the cosmic rays in the energy range
E > 1020 eV, the upper end of the spectrum observed to date, with a large statistical significance (103 events/year), and hence address the solution of several
astrophysical and cosmological problems related to their existence and behaviour, a new generation of experiments will probably have to be conceived and realised. They will be based on the observation and measurements of cosmic rays from space. The extremely low rate of these events (∼ 1 event/(century × km2 × sr)) imposes a very large effective area to be monitored, of the order of 105 km2, as an observational requirement to meet the target statistics. The Extreme Universe Space Observatory (EUSO)mission has been proposed as the precursor of this new generation of experiments. Its approach consists in fact in looking downwards to the Earth atmosphere by means of a large
field-of-view telescope accommodated aboard an orbiting satellite. The fluorescence strike produced by a cosmic ray through the atmosphere will be recorded by the detector, which will reconstruct the kinematical and dynamical features of the primary cosmic ray. The atmosphere acts therefore as an active target for the detectable event. A strategic tool for the success of EUSO as well as for all the experiments of its category will be a correct and detailed atmospheric sounding system, in order to monitor the atmospheric parameters within the field-of-view of the telescope. Beside an on-board measurement by means of dedicated devices such an infrared camera (IR)and possibly a LIDAR (LIght Detection And Ranging)coupled to the main instrument, the Atmosphere Sounding will take advantage from the continuous observation of the atmospheric parameters given by the orbiting meteorological satellites. Their databases have thus to be interfaced to the experimental data and used picking-up the relevant data according to the space and time coordinates corresponding
to each triggered event. The present work outlines a software module (MARVIN-Multiparametric Advanced Research tool for Visualisation In the Network) able to build-up such an interface, and shows a preliminary implementation
of it, using a sample of existing satellites and ISCCP meteorological data collection. It has been developed during the phase A study of the EUSO mission but is general
enough to be adapted to different missions observing the Earth atmosphere from space
Weak anisotropy and disorder dependence of the in-plane magnetoresistance in high mobility (100) Si-inversion layers
We report studies of the magnetoresistance (MR) in a two-dimensional electron
system in (100) Si-inversion layers, for perpendicular and parallel
orientations of the current with respect to the magnetic field in the 2D-plane.
The magnetoresistance is almost isotropic; this result does not support the
suggestion of the orbital origin of the MR in Si-inversion layer. In the
hopping regime, however, the MR contains a weak anisotropic component that is
non-monotonic in magnetic field. We found that the field, at which the MR
saturates, for different samples varies by a factor of two, being lower or
higher than the field of complete spin polarization of free carriers.
Therefore, the saturation of the MR can not be identified with the spin
polarization of free carriers.Comment: 4 pages, 4 figures; New data adde
A Novel Protein Hydrolysate-Based Biostimulant Improves Tomato Performances under Drought Stress
Abiotic stresses adversely affect crop production causing yield reductions in important crops, including tomato (Solanum lycopersicum L.). Among the different abiotic stresses, drought is considered to be the most critical one, since limited water availability negatively impacts plant growth and development, especially in arid and semi-arid areas. The aim of this study was to understand how biostimulants may interact with critical physiological response mechanisms in tomato under limited water availability and to define strategies to improve tomato performances under drought stress. We investigated the physiological responses of the tomato genotype ‘E42’ grown in open fields under optimal conditions (100% irrigation) and limited water availability (50% irrigation) treated or not with a novel protein hydrolysate-based biostimulant (CycoFlow, Agriges, BN, Italy). Plants treated with the protein hydrolysate showed a better water status and pollen viability, which also resulted in higher yield under drought stress compared to untreated plants. The treatment with the biostimulant had also an effect on antioxidant contents and activity in leaves and fruits depending on the level of irrigation provided. Altogether, these results indicate that the application of protein hydrolysates on tomato improved plant performances under limited water availability and in different experimental fields
Recurrence of the oxazole motif in tubulin colchicine site inhibitors with anti-tumor activity
Because of its wide spectrum of targets and biological activities, the oxazole ring is a valuable heterocyclic scaffold in the design of new therapeutic agents with anticancer, antiviral, antibacterial, anti-inflammatory, neuroprotective, antidiabetic and antidepressant properties. The presence of two heteroatoms, oxygen and nitrogen, offers possible interactions (hydrogen, hydrophobic, van der Waals or dipoles bonds) with a broad range of receptors and enzymes. Furthermore, the oxazole core conjugates low cytotoxicity with improved compound solubility and is well suited to structural modifications such as substitution with different groups and condensation to aromatic, heteroaromatic or non-aromatic rings, offering diversity when introduced into scaffolds. These features make it a very attractive nucleus in medicinal chemistry. Herein we present a diverse array of oxazole derivatives with potential therapeutic use in multiple tumor models. The emphasis has been addressed to compounds with anti-tubulin activity reported in literature in the last decade, describing their structural features, efficiency and future perspectives
GPCR Inhibition in Treating Lymphoma
G protein-coupled receptors (GPCRs) are important classes of cell surface receptors involved in multiple physiological functions. Aberrant expression, upregulation, and mutation of GPCR signaling pathways are frequent in many types of cancers, promoting hyperproliferation, angiogenesis, and metastasis. Recent studies showed that alterations of GPCRs are involved in different lymphoma types. Herein, we review the synthetic strategies to obtain GPCR inhibitors, focusing on CXCR4 inhibitors which represent most of the GPCR inhibitors available in the market or under preclinical investigations for these diseases
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