427 research outputs found
Machine learning techniques for MRI feature-based detection of frontotemporal lobar degeneration
Making a diagnosis of neurodegenerative diseases at an early stage is one of the most significant challenges of modern neuroscience. Although this family of diseases remains without a cure, the effectiveness of their medical treatment largely relies on the timing of their detection. For certain groups of diseases, such as Fronto-Temporal Dementia (FTD), trained professionals can effectively reach a correct diagnosis through the visual analysis of Magnetic Resonance Imaging, in its functional (fMRI) or raw (MRI) version. However, this operation is time-consuming and may be subject to personal interpretation. In this paper, we explore the performance of a group of machine learning algorithms to formulate a correct FTD diagnosis, in order to provide medical professionals with a supporting tool. The dataset consists of MRI data acquired on 30 subjects, and the experiments are carried out by investigating different fMRI techniques based on a Multi-Voxel Pattern Analysis (MVPA) approach. The results obtained show high accuracy in identifying FTD in elderly patients when Support Vector Machine and Random Forest techniques are used, with outcomes varying based on the fMRI methods
Nonlinear Two-Dimensional Green's Function in Smectics
The problem of the strain of smectics subjected to a force distributed over a
line in the basal plane has been solved
Organization and management of clusters in Russia in the context of import substitution
The article covers the trends of the agribusiness development in Russia. It is shown that it is desirable to develop organizational-economic forms of entrepreneurship based on the cluster approach in the modern realities.
The most famous agribusiness clusters in the world are explored. Regions of Russia that have achieved the most significant results in agribusiness clustering are mentioned. It is found that the establishment of agribusiness in Russia is defined by the political decision of regional authorities rather than based on research and development.
An algorithm for establishing the agribusiness cluster is proposed, which includes four stages: methodological, analytical, organizational-economic and control.
The key areas of state support for the development of agribusiness clusters in Russia are defined.peer-reviewe
Review of scientific topics for Millimetron space observatory
This paper describes outstanding issues in astrophysics and cosmology that
can be solved by astronomical observations in a broad spectral range from far
infrared to millimeter wavelengths. The discussed problems related to the
formation of stars and planets, galaxies and the interstellar medium, studies
of black holes and the development of the cosmological model can be addressed
by the planned space observatory Millimetron (the "Spectr-M" project) equipped
with a cooled 10-m mirror. Millimetron can operate both as a single-dish
telescope and as a part of a space-ground interferometer with very long
baseline.Comment: The translation of the original article in Physics Uspekhi
http://ufn.ru/ru/articles/2014/12/c
A Quench Detection and Monitoring System for Superconducting Magnets at Fermilab
A quench detection system was developed for protecting and monitoring the
superconducting solenoids for the Muon-to-Electron Conversion Experiment (Mu2e)
at Fermilab. The quench system was designed for a high level of dependability
and long-term continuous operation. It is based on three tiers: Tier-I,
FPGA-based Digital Quench Detection (DQD); Tier-II, Analog Quench Detection
(AQD); and Tier-3, the quench controls and data management system. The Tier-I
and Tier-II are completely independent and fully redundant systems. The Tier-3
system is based on National Instruments (NI) C-RIO and provides the user
interface for quench controls and data management. It is independent from Tiers
I & II. The DQD provides both quench detection and quench characterization
(monitoring) capability. Both DQD and AQD have built-in high voltage isolation
and user programmable gains and attenuations. The DQD and AQD also includes
user configured current dependent thresholding and validation times.
A 1st article of the three-tier system was fully implemented on the new
Fermilab magnet test stand for the HL-LHC Accelerator Up-grade Project (AUP).
It successfully provided quench protection and monitoring (QPM) for a cold
superconducting bus test in November 2020. The Mu2e quench detection design has
since been implemented for production testing of the AUP magnets. A detailed
description of the system along with results from the AUP superconducting bus
test will be presented
Associating ground magnetometer observations with current or voltage generators
A circuit analogy for magnetosphere‐ionosphere current systems has two extremes for drivers of ionospheric currents: ionospheric electric fields/voltages constant while current/conductivity vary—the “voltage generator”—and current constant while electric field/conductivity vary—the “current generator.” Statistical studies of ground magnetometer observations associated with dayside Transient High Latitude Current Systems (THLCS) driven by similar mechanisms find contradictory results using this paradigm: some studies associate THLCS with voltage generators, others with current generators. We argue that most of this contradiction arises from two assumptions used to interpret ground magnetometer observations: (1) measurements made at fixed position relative to the THLCS field‐aligned current and (2) negligible auroral precipitation contributions to ionospheric conductivity. We use observations and simulations to illustrate how these two assumptions substantially alter expectations for magnetic perturbations associated with either a current or a voltage generator. Our results demonstrate that before interpreting ground magnetometer observations of THLCS in the context of current/voltage generators, the location of a ground magnetometer station relative to the THLCS field‐aligned current and the location of any auroral zone conductivity enhancements need to be taken into account.Key PointsConductivity and location assumptions used to interpret ground magnetic perturbations yield conflicting resultsHigh‐latitude currents associated with voltage generators may instead be associated with current generators, and vice versaWithout better constraints on conductivity/station location relative to currents, conflicts will not be resolvedPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138366/1/jgra53632.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138366/2/jgra53632_am.pd
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