2,344 research outputs found
Self-mentoring: a new deep learning pipeline to train a self-supervised U-net for few-shot learning of bio-artificial capsule segmentation
Background: Accurate segmentation of microscopic structures such as
bio-artificial capsules in microscopy imaging is a prerequisite to the
computer-aided understanding of important biomechanical phenomenons.
State-of-the-art segmentation performances are achieved by deep neural networks
and related data-driven approaches. Training these networks from only a few
annotated examples is challenging while producing manually annotated images
that provide supervision is tedious.
Method: Recently, self-supervision, i.e. designing a neural pipeline
providing synthetic or indirect supervision, has proved to significantly
increase generalization performances of models trained on few shots. The
objective of this paper is to introduce one such neural pipeline in the context
of micro-capsule image segmentation. Our method leverages the rather simple
content of these images so that a trainee network can be mentored by a referee
network which has been previously trained on synthetically generated pairs of
corrupted/correct region masks.
Results: Challenging experimental setups are investigated. They involve from
only 3 to 10 annotated images along with moderately large amounts of
unannotated images. In a bio-artificial capsule dataset, our approach
consistently and drastically improves accuracy. We also show that the learnt
referee network is transferable to another Glioblastoma cell dataset and that
it can be efficiently coupled with data augmentation strategies.
Conclusions: Experimental results show that very significant accuracy
increments are obtained by the proposed pipeline, leading to the conclusion
that the self-supervision mechanism introduced in this paper has the potential
to replace human annotations
Ecoute microsismique appliquée aux versants instables, exemple des ruines de Séchilienne (Isère, 38)
International audienceField observations and movements measured since 1985 by the Lyon CETE (Public works regional engineering office) monitoring system at the Ruines de Séchilienne show that the slope deformation and fault mechanisms are complex. To provide a deeper understanding of these mechanisms, INERIS has been investigating the site through the instrumentation of deep drillholes since 2009. An experimental multi-parameter monitoring system was installed on the western edge of the large active zone. It uses an integrated technology platform which combines microseismic, geotechnical, hydrogeological, meteorological and 3D displacements. The article outlines the objectives and the methodology applied by INERIS to meet the requirements of early warning multi-parameter systems applied to unstable rock slopes. The studied site and the main characteristics of the system are presented. Items dealing with the system calibration and characterization data are described and preliminary data are givenLes observations et les mouvements mesurés, depuis 1985, par le système de surveillance du CETE de Lyon sur le mouvement des Ruines de Séchilienne, montrent que les mécanismes de déformation et rupture du versant sont complexes. Pour progresser dans la compréhension de ces mécanismes, l'INERIS contribue depuis 2009 aux investigations menées sur le site par forages profonds. Un système d'observation multi-paramètres a ainsi été installé en bordure Ouest de la zone active. Il fait appel à une plateforme technologique intégrée qui combine des mesures microsismiques, géotechniques, hydrologiques, météorologiques et des mesures de déplacement tridimensionnel. L'article décrit les objectifs de la démarche et la méthodologie mise en oeuvre par l'INERIS pour répondre aux exigences des systèmes d'alerte précoce multi-paramètres, appliqués aux mouvements de versants instables. Le site d'étude et les principales caractéristiques du dispositif sont présentés. Des considérations sur le calibrage du système et la qualification des données sont décrites et les premières données sont présentées
Les inclusions intranucléaires de la dystrophie musculaire oculopharyngée (DMOP) : relation entre composition, localisation et expression
Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal
EFSA Guidance Document for evaluating laboratory and field dissipation studies to obtain DegT50 values of active substances of plant protection products and transformation products of these active substances in soil
EFSA was asked by the European Commission to prepare a Guidance of EFSA for evaluating laboratory and field dissipation studies to obtain degradation rate parameters (DegT50matrix values) of active substances of plant protection products and transformation products of these active substances in soil. This EFSA Guidance Document provides guidance for users on how to obtain DegT50matrix values when performing risk assessments according to Regulation EC No 1107/2009 of the European Parliament and the Council. In addition, this document provides guidance on adsorption parameter (Koc) selection and new Crop Interception values
A zone of preferential ion heating extends tens of solar radii from Sun
The extreme temperatures and non-thermal nature of the solar corona and solar
wind arise from an unidentified physical mechanism that preferentially heats
certain ion species relative to others. Spectroscopic indicators of unequal
temperatures commence within a fraction of a solar radius above the surface of
the Sun, but the outer reach of this mechanism has yet to be determined. Here
we present an empirical procedure for combining interplanetary solar wind
measurements and a modeled energy equation including Coulomb relaxation to
solve for the typical outer boundary of this zone of preferential heating.
Applied to two decades of observations by the Wind spacecraft, our results are
consistent with preferential heating being active in a zone extending from the
transition region in the lower corona to an outer boundary 20-40 solar radii
from the Sun, producing a steady state super-mass-proportional
-to-proton temperature ratio of . Preferential ion heating
continues far beyond the transition region and is important for the evolution
of both the outer corona and the solar wind. The outer boundary of this zone is
well below the orbits of spacecraft at 1 AU and even closer missions such as
Helios and MESSENGER, meaning it is likely that no existing mission has
directly observed intense preferential heating, just residual signatures. We
predict that {Parker Solar Probe} will be the first spacecraft with a perihelia
sufficiently close to the Sun to pass through the outer boundary, enter the
zone of preferential heating, and directly observe the physical mechanism in
action.Comment: 11 pages, 7 figures, accepted for publication in the Astrophysical
Journal on 1 August 201
Approximations for radiative cooling and heating in the solar chromosphere
Context. The radiative energy balance in the solar chromosphere is dominated
by strong spectral lines that are formed out of LTE. It is computationally
prohibitive to solve the full equations of radiative transfer and statistical
equilibrium in 3D time dependent MHD simulations.
Aims. To find simple recipes to compute the radiative energy balance in the
dominant lines under solar chromospheric conditions.
Methods. We use detailed calculations in time-dependent and 2D MHD snapshots
to derive empirical formulae for the radiative cooling and heating.
Results. The radiative cooling in neutral hydrogen lines and the Lyman
continuum, the H and K and intrared triplet lines of singly ionized calcium and
the h and k lines of singly ionized magnesium can be written as a product of an
optically thin emission (dependent on temperature), an escape probability
(dependent on column mass) and an ionization fraction (dependent on
temperature). In the cool pockets of the chromosphere the same transitions
contribute to the heating of the gas and similar formulae can be derived for
these processes. We finally derive a simple recipe for the radiative heating of
the chromosphere from incoming coronal radiation. We compare our recipes with
the detailed results and comment on the accuracy and applicability of the
recipes.Comment: accepted for publication in Astronomy & Astrophysic
Exploring Accretion and Disk-Jet Connections in the LLAGN M81*
We report on a year-long effort to monitor the central supermassive black
hole in M81 in the X-ray and radio bands. Using Chandra and the VLA, we
obtained quasi-simultaneous observations of M81* on seven occasions during
2006. The X-ray and radio luminosity of M81* are not strongly correlated on the
approximately 20-day sampling timescale of our observations, which is
commensurate with viscous timescales in the inner flow and orbital timecales in
a radially-truncated disk. This suggests that short-term variations in black
hole activity may not be rigidly governed by the "fundamental plane", but
rather adhere to the plane in a time-averaged sense. Fits to the X-ray spectra
of M81* with bremsstrahlung models give temperatures that are inconsistent with
the outer regions of very simple advection-dominated inflows. However, our
results are consistent with the X-ray emission originating in a transition
region where a truncated disk and advective flow may overlap. We discuss our
results in the context of models for black holes accreting at small fractions
of their Eddington limit, and the fundamental plane of black hole accretion.Comment: Accepted for publication in Ap
A gate-variable spin current demultiplexer based on graphene
Spintronics, which utilizes spin as information carrier, is a promising
solution for nonvolatile memory and low-power computing in the post-Moore era.
An important challenge is to realize long distance spin transport, together
with efficient manipulation of spin current for novel logic-processing
applications. Here, we describe a gate-variable spin current demultiplexer
(GSDM) based on graphene, serving as a fundamental building block of
reconfigurable spin current logic circuits. The concept relies on electrical
gating of carrier density dependent conductivity and spin diffusion length in
graphene. As a demo, GSDM is realized for both single-layer and bilayer
graphene. The distribution and propagation of spin current in the two branches
of GSDM depend on spin relaxation characteristics of graphene. Compared with
Elliot-Yafet spin relaxation mechanism, D'yakonov-Perel mechanism results in
more appreciable gate-tuning performance. These unique features of GSDM would
give rise to abundant spin logic applications, such as on-chip spin current
modulators and reconfigurable spin logic circuits.Comment: 18 pages,3 figures,1 tabl
Inflammatory Profile of Awake Function-Controlled Craniotomy and Craniotomy under General Anesthesia
Background. Surgical stress triggers an inflammatory response and releases mediators into human plasma such as interleukins (ILs). Awake craniotomy and craniotomy performed under general anesthesia may be associated with different levels of stress. Our aim was to investigate whether those procedures cause different inflammatory responses.
Methods. Twenty patients undergoing craniotomy under general anesthesia and 20 patients undergoing awake function-controlled craniotomy were included in this prospective, observational, two-armed study. Circulating levels of IL-6, IL-8, and IL-10 were determined pre-, peri-, and postoperatively in both patient groups. VAS scores for pain, anxiety, and stress were taken at four moments pre- and postoperatively to evaluate physical pain and mental duress.
Results. Plasma IL-6 level significantly increased with time similarly in both groups. No significant plasma IL-8 and IL-10 change was observed in both experimental groups. The VAS pain score was significantly lower in the awake group compared to the anesthesia group at 12 hours postoperative. Postoperative anxiety and stress declined similarly in both groups.
Conclusion. This study suggests that awake function-controlled craniotomy does not cause a significantly different inflammatory response than craniotomy performed under general anesthesia. It is also likely that function-controlled craniotomy does not cause a greater emotional challenge than tumor resection under general anesthesia
- …