3,346 research outputs found
Long-Range Order in Electronic Transport through Disordered Metal Films
Ultracold atom magnetic field microscopy enables the probing of current flow
patterns in planar structures with unprecedented sensitivity. In
polycrystalline metal (gold) films we observe long-range correlations forming
organized patterns oriented at +/- 45 deg relative to the mean current flow,
even at room temperature and at length scales orders of magnitude larger than
the diffusion length or the grain size. The preference to form patterns at
these angles is a direct consequence of universal scattering properties at
defects. The observed amplitude of the current direction fluctuations scales
inversely to that expected from the relative thickness variations, the grain
size and the defect concentration, all determined independently by standard
methods. This indicates that ultracold atom magnetometry enables new insight
into the interplay between disorder and transport
An original application of image recognition based location in complex indoor environments
This paper describes the first results of an image recognition based location (IRBL) for a mobile application focusing on the procedure to generate a database of range images (RGB-D). In an indoor environment, to estimate the camera position and orientation, a prior spatial knowledge of the surroundings is needed. To achieve this objective, a complete 3D survey of two different environments (Bangbae metro station of Seoul and the Electronic and Telecommunications Research Institute (ETRI) building in Daejeon, Republic of Korea) was performed using a LiDAR (Light Detection and Ranging) instrument, and the obtained scans were processed to obtain a spatial model of the environments. From this, two databases of reference images were generated using specific software realised by the Geomatics group of Politecnico di Torino (ScanToRGBDImage). This tool allows us to generate synthetically different RGB-D images centred in each scan position in the environment. Later, the external parameters (X, Y, Z, ω, ϕ, and κ) and the range information extracted from the retrieved database images are used as reference information for pose estimation of a set of acquired mobile pictures in the IRBL procedure. In this paper, the survey operations, the approach for generating the RGB-D images, and the IRB strategy are reported. Finally, the analysis of the results and the validation test are described
Arabidopsis SABRE and CLASP interact to stabilize cell division plane orientation and planar polarity
The orientation of cell division and the coordination of cell polarity within the plane of the tissue layer (planar polarity) contribute to shape diverse multicellular organisms. The root of Arabidopsis thaliana displays regularly oriented cell divisions, cell elongation and planar polarity providing a plant model system to study these processes. Here we report that the SABRE protein, which shares similarity with proteins of unknown function throughout eukaryotes, has important roles in orienting cell division and planar polarity. SABRE localizes at the plasma membrane, endomembranes, mitotic spindle and cell plate. SABRE stabilizes the orientation of CLASP-labelled preprophase band microtubules predicting the cell division plane, and of cortical microtubules driving cell elongation. During planar polarity establishment, sabre is epistatic to clasp at directing polar membrane domains of Rho-of-plant GTPases. Our findings mechanistically link SABRE to CLASP-dependent microtubule organization, shedding new light on the function of SABRE-related proteins in eukaryotes
Manifestly Gauge Covariant Treatment of Lattice Chiral Fermions. II
We propose a new formulation of chiral fermions on a lattice, on the basis of
a lattice extension of the covariant regularization scheme in continuum field
theory. The species doublers do not emerge. The real part of the effective
action is just one half of that of Dirac-Wilson fermion and is always gauge
invariant even with a finite lattice spacing. The gauge invariance of the
imaginary part, on the other hand, sets a severe constraint which is a lattice
analogue of the gauge anomaly free condition. For real gauge representations,
the imaginary part identically vanishes and the gauge invariance becomes exact.Comment: 15 pages, PHYZZX. The title is changed. The final version to appear
in Phys. Rev.
The use of nanocrystal quantum dot as fluorophore reporters in molecular beacon-based assays
textversion:publishe
System Test of the ATLAS Muon Spectrometer in the H8 Beam at the CERN SPS
An extensive system test of the ATLAS muon spectrometer has been performed in
the H8 beam line at the CERN SPS during the last four years. This spectrometer
will use pressurized Monitored Drift Tube (MDT) chambers and Cathode Strip
Chambers (CSC) for precision tracking, Resistive Plate Chambers (RPCs) for
triggering in the barrel and Thin Gap Chambers (TGCs) for triggering in the
end-cap region. The test set-up emulates one projective tower of the barrel
(six MDT chambers and six RPCs) and one end-cap octant (six MDT chambers, A CSC
and three TGCs). The barrel and end-cap stands have also been equipped with
optical alignment systems, aiming at a relative positioning of the precision
chambers in each tower to 30-40 micrometers. In addition to the performance of
the detectors and the alignment scheme, many other systems aspects of the ATLAS
muon spectrometer have been tested and validated with this setup, such as the
mechanical detector integration and installation, the detector control system,
the data acquisition, high level trigger software and off-line event
reconstruction. Measurements with muon energies ranging from 20 to 300 GeV have
allowed measuring the trigger and tracking performance of this set-up, in a
configuration very similar to the final spectrometer. A special bunched muon
beam with 25 ns bunch spacing, emulating the LHC bunch structure, has been used
to study the timing resolution and bunch identification performance of the
trigger chambers. The ATLAS first-level trigger chain has been operated with
muon trigger signals for the first time
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
- …