1,112 research outputs found
Tuning a Resonance in the Fock Space: Optimization of Phonon Emission in a Resonant Tunneling Device
Phonon-assisted tunneling in a double barrier resonant tunneling device can
be seen as a resonance in the electron-phonon Fock space which is tuned by the
applied voltage. We show that the geometrical parameters can induce a symmetry
condition in this space that can strongly enhance the emission of longitudinal
optical phonons. For devices with thin emitter barriers this is achieved by a
wider collector's barrier.Comment: 4 pages, 3 figures. Figure 1 changed, typos correcte
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Detection of PittâHopkins syndrome based on morphological facial features
This work describes a non-invasive, automated software framework to discriminate between individuals with a genetic disorder, PittâHopkins syndrome (PTHS), and healthy individuals through the identification of morphological facial features. The input data consist of frontal facial photographs in which faces are located using histograms of oriented gradients feature descriptors. Pre-processing steps include color normalization and enhancement, scaling down, rotation, and cropping of pictures to produce a series of images of faces with consistent dimensions. Sixty-eight facial landmarks are automatically located on each face through a cascade of regression functions learnt via gradient boosting to estimate the shape from an initial approximation. The intensities of a sparse set of pixels indexed relative to this initial estimate are used to determine the landmarks. A set of carefully selected geometric features, for example, the relative width of the mouth or angle of the nose, is extracted from the landmarks. The features are used to investigate the statistical differences between the two populations of PTHS and healthy controls. The methodology was tested on 71 individuals with PTHS and 55 healthy controls. The software was able to classify individuals with an accuracy rate of 91%, while pediatricians achieved a recognition rate of 74%. Two geometric features related to the nose and mouth showed significant statistical difference between the two populations
Sospensione del fumo alla prima diagnosi di carcinoma non muscolo invasivo della vescica (NMIBC) e rischio di recidiva
Accuracy of a method based on atomic absorption spectrometry to determine inorganic arsenic in food : Outcome of the collaborative trial IMEP-41
Peer reviewedPublisher PD
Retrospective-Cost Adaptive Control of Uncertain Hammerstein-Wiener Systems with Memoryless and Hysteretic Nonlinearities
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97108/1/AIAA2012-4449.pd
Comparison of mid-latitude single- And mixed-phase cloud optical depth from co-located infrared spectrometer and backscatter lidar measurements
The long-wave downwelling spectral radiance measurements performed by means of the Far-Infrared Radiation Mobile Observation System (FIRMOS) spectrometer at the summit of the Zugspitze (German Alps) in the winter 2018/19 allowed the retrieval of the optical and micro-physical properties of ice and mixed clouds, showing a good agreement of the statistical relationship between the ice water path and the ice optical depth with the ones from previous works. In this paper the optical depths retrieved from FIRMOS are initially compared with selected cases calculated from backscattering light detection and ranging (lidar) data by using a transmittance method. Then, in order to compare the whole FIRMOS dataset, the power-law relationship between backscattering and extinction is used to apply the Klett method and automatize the routine. Minimizing the root mean square differences, the exponent k of the power-law relationship is assessed to be 0.85 with a variability in the range of 0.60â1.10 for ice clouds and 0.50 with a variability within 0.30â0.70 for mixed clouds
The far-infrared/radio correlation for a sample of strongly lensed dusty star-forming galaxies detected by Herschel
We investigate the radio/far-infrared (FIR) correlation for a sample of 28 bright high-redshift (1 z 4) star-forming galaxies selected in the FIR from the Herschel -ATLAS fields as candidates to be strongly gravitationally lensed. The radio information comes either from high sensitivity dedicated Australia Telescope Compact Array observations at 2.1 GHz or from cross-matches with the FIRST surv e y at 1.4 GHz. By taking advantage of source brightness possibly enhanced by lensing magnification, we identify a weak evolution with redshift out to z 4 of the FIR-to-radio luminosity ratio q FIR . We also find that the q FIR parameter as a function of the radio power L 1 . 4 GHz displays a clear decreasing trend, similarly to what is observed for optically/radio- selected lensed quasars found in literature, yet co v ering a complementary region in the q FIR âL 1 . 4 GHz diagram. We interpret such a behaviour in the framework of an in situ galaxy formation scenario, as a result of the transition from an early dust-obscured star-forming phase (mainly pinpointed by our FIR selection) to a late radio-loud quasar phase (preferentially sampled by the optical/radio selection)
Time evolution of stimulated Raman scattering and two-plasmon decay at laser intensities relevant for shock ignition in a hot plasma
Laserâplasma interaction (LPI) at intensities 1015â1016 W cm2 is dominated by parametric instabilities which can be
responsible for a significant amount of non-collisional absorption and generate large fluxes of high-energy nonthermal
electrons. Such a regime is of paramount importance for inertial confinement fusion (ICF) and in particular for the
shock ignition scheme. In this paper we report on an experiment carried out at the Prague Asterix Laser System (PALS)
facility to investigate the extent and time history of stimulated Raman scattering (SRS) and two-plasmon decay (TPD)
instabilities, driven by the interaction of an infrared laser pulse at an intensity 1:2 1016 W cm2 with a 100 mm
scalelength plasma produced from irradiation of a flat plastic target. The laser pulse duration (300 ps) and the high
value of plasma temperature (4 keV) expected from hydrodynamic simulations make these results interesting for a
deeper understanding of LPI in shock ignition conditions. Experimental results show that absolute TPD/SRS, driven at
a quarter of the critical density, and convective SRS, driven at lower plasma densities, are well separated in time, with
absolute instabilities driven at early times of interaction and convective backward SRS emerging at the laser peak and
persisting all over the tail of the pulse. Side-scattering SRS, driven at low plasma densities, is also clearly observed.
Experimental results are compared to fully kinetic large-scale, two-dimensional simulations. Particle-in-cell results,
beyond reproducing the framework delineated by the experimental measurements, reveal the importance of filamentation
instability in ruling the onset of SRS and stimulated Brillouin scattering instabilities and confirm the crucial role of
collisionless absorption in the LPI energy balance
Quantum transport and momentum conserving dephasing
We study numerically the influence of momentum-conserving dephasing on the
transport in a disordered chain of scatterers. Loss of phase memory is caused
by coupling the transport channels to dephasing reservoirs. In contrast to
previously used models, the dephasing reservoirs are linked to the transport
channels between the scatterers, and momentum conserving dephasing can be
investigated. Our setup provides a model for nanosystems exhibiting conductance
quantization at higher temperatures in spite of the presence of phononic
interaction. We are able to confirm numerically some theoretical predictions.Comment: 7 pages, 4 figure
Which phase is measured in the mesoscopic Aharonov-Bohm interferometer?
Mesoscopic solid state Aharonov-Bohm interferometers have been used to
measure the "intrinsic" phase, , of the resonant quantum
transmission amplitude through a quantum dot (QD). For a two-terminal "closed"
interferometer, which conserves the electron current, Onsager's relations
require that the measured phase shift only "jumps" between 0 and .
Additional terminals open the interferometer but then depends on the
details of the opening. Using a theoretical model, we present quantitative
criteria (which can be tested experimentally) for to be equal to the
desired : the "lossy" channels near the QD should have both a
small transmission and a small reflection
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