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•It is revealed that more than 42 different statistical method are proposed to localize brain activity sources using EEG signals.•Sparse Bayesian learning algorithm provides more ...accurate localization results using an estimate of the sensor noise covariance and brain atlases.•Reducing the location error of the electrodes and enough sampling of the potential surface field can improve the localization approaches.•It is also clear that different psychiatric disorders are more likely to be diagnosed and cured through brain source localization methods.
In recent years, multiple noninvasive imaging modalities have been used to develop a better understanding of the human brain functionality, including positron emission tomography, single-photon emission computed tomography, and functional magnetic resonance imaging, all of which provide brain images with millimeter spatial resolutions. Despite good spatial resolution, time resolution of these methods are poor and values are about seconds. Scalp electroencephalography recordings can be used to perform the inverse problem in order to specify the location of the dominant sources of the brain activity. In this paper, EEG source localization method, diagnosis of brain abnormalities using common EEG source localization methods, investigating the effect of the head model on EEG source imaging results have been studied. In this review we present enough evidence that provides motivation for consideration in the future research using EEG source localization methods.
A new (Gd,Lu,Y)3Al2Ga3O12:Ce, Mg scintillation material was produced in transparent ceramic form for the first time. 1.5-mm-thick samples for the evaluation performance test were produced from ...coprecipitated powders by sintering in an oxygen atmosphere at 1720 °C for 2 h. The scintillator ensures a coincidence time resolution of less than 100 ps when utilizing the silicon photo-multiplier (SiPM) readout. This finding suggest that the material is quite promising for positron emission tomographs (PET) utilizing time-off-flight (TOF) techniques for the registration of annihilation 511 keV gamma-quanta. A significantly lower production temperature, absence in the production cycle of precious metals like Ir and Pt, and high rate of crystalline mass production in the absence of high-pressure sintering in the manufacturing chain make the developed ceramic a competitor to a widely used (Lu,Y)2SiO5 single crystalline scintillator, in particular, for full-body PET scanners.
•A new (Gd,Lu,Y)3Al2Ga3O12:Ce, Mg scintillation transparent ceramic was produced by a pressure free sintering.•The scintillator provides the coincidence time resolution for 511 keV as less as 100 ps.•The material is quite promising for positron emission tomographs (PET) utilizing time-off-flight (TOF) techniques.
As the widespread application of online instruments penetrates the environmental fields, it is interesting to investigate the sources of fine particulate matter (PM2.5) based on the data monitored by ...online instruments. In this study, online analyzers with 1-h time resolution were employed to observe PM2.5 composition data, including carbon components, inorganic ions, heavy metals and gas pollutants, during a summer in Beijing. Chemical characteristics, temporal patterns and sources of PM2.5 are discussed. On the basis of hourly data, the mean concentration value of PM2.5 was 62.16±39.37μgm−3 (ranging from 6.69 to 183.67μgm−3). The average concentrations of NO3−, SO42−, NH4+, OC and EC, the major chemical species, were 15.18±13.12, 14.80±14.53, 8.90±9.51, 9.32±4.16 and 3.08±1.43μgm−3, respectively. The concentration of PM2.5 varied during the online-sampling period, initially increasing and then subsequently decreasing. Three factor analysis models, including principal component analysis (PCA), positive matrix factorization (PMF) and Multilinear Engine 2 (ME2), were applied to apportion the PM2.5 sources. Source apportionment results obtained by the three different models were in agreement. Four sources were identified in Beijing during the sampling campaign, including secondary sources (38–39%), crustal dust (17–22%), vehicle exhaust (25–28%) and coal combustion (15–16%). Similar source profiles and contributions of PM2.5 were derived from ME2 and PMF, indicating the results of the two models are reasonable. The finding provides information that could be exploited for regular air control strategies.
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•PM2.5 was measured by online instruments with 1-h time resolution in Beijing.•Chemical characteristic and temporal patterns of PM2.5 and components were discussed.•PCA, PMF and ME2, were applied to apportion the sources based on the online dataset.
•Sensitivity of streamflow simulation to hydrologic modeling resolution is assessed.•Two radar-based precipitation input of different resolution are used for comparison.•Streamflow prediction ...improved with higher resolution up to about 500m and 15min.•There are trade-offs among resolution and timeliness and accuracy of prediction.
Urban flash flooding is a serious problem in large, highly populated areas such as the Dallas–Fort Worth Metroplex (DFW). Being able to monitor and predict flash flooding at a high spatiotemporal resolution is critical to providing location-specific early warnings and cost-effective emergency management in such areas. Under the idealized conditions of perfect models and precipitation input, one may expect that spatiotemporal specificity and accuracy of the model output improve as the resolution of the models and precipitation input increases. In reality, however, due to the errors in the precipitation input, and in the structures, parameters and states of the models, there are practical limits to the model resolution. In this work, we assess the sensitivity of streamflow simulation in urban catchments to the spatiotemporal resolution of precipitation input and hydrologic modeling to identify the resolution at which the simulation errors may be at minimum given the quality of the precipitation input and hydrologic models used, and the response time of the catchment. The hydrologic modeling system used in this work is the National Weather Service (NWS) Hydrology Laboratory’s Research Distributed Hydrologic Model (HLRDHM) applied at spatiotemporal resolutions ranging from 250m to 2km and from 1min to 1h applied over the Cities of Fort Worth, Arlington and Grand Prairie in DFW. The high-resolution precipitation input is from the DFW Demonstration Network of the Collaborative Adaptive Sensing of the Atmosphere (CASA) radars. For comparison, the NWS Multisensor Precipitation Estimator (MPE) product, which is available at a 4-km 1-h resolution, was also used. The streamflow simulation results are evaluated for 5 urban catchments ranging in size from 3.4 to 54.6km2 and from about 45min to 3h in time-to-peak in the Cities of Fort Worth, Arlington and Grand Prairie. The streamflow observations used in evaluation were obtained from water level measurements via rating curves derived from 1-D steady-state non-uniform hydraulic modeling. The results indicate that a spatiotemporal resolution of 500m and 15min or higher is a good choice for streamflow prediction using HLRDHM and CASA QPE in the study area, but that, due to the nonlinear accretion of random errors in QPE and imperfect model dynamics, there are trade-offs to consider among resolution, timeliness of prediction and prediction accuracy.
ABSTRACT We perform a time-resolved spectral analysis of GRB 130606B within the framework of a fast-cooling synchrotron radiation model with magnetic field strength in the emission region decaying ...with time, as proposed by Uhm & Zhang. The data from all time intervals can be successfully fit by the model. The same data can be equally well fit by the empirical Band function with typical parameter values. Our results, which involve only minimal physical assumptions, offer one natural solution to the origin of the observed GRB spectra and imply that, at least some, if not all, Band-like GRB spectra with typical Band parameter values can indeed be explained by synchrotron radiation.
We present here the first release of the open-source python package ExoTETHyS (stable: https://zenodo.org/badge/latestdoi/169268509, development version: ...https://github.com/ucl-exoplanets/ExoTETHyS/), which aims to provide a stand-alone set of tools for modeling spectrophotometric observations of transiting exoplanets. In particular, we describe: (1) a new calculator of stellar limb-darkening coefficients that outperforms the existing software by one order of magnitude in terms of light-curve model accuracy, i.e., down to <10 parts per million, and (2) an exact transit light-curve generator based on the entire stellar intensity profile rather than limb-darkening coefficients. New tools will be added in later releases to model various effects in exoplanetary transits and eclipsing binaries. ExoTETHyS is a reference package for high-precision exoplanet atmospheric spectroscopy with the upcoming James Webb Space Telescope and Atmospheric Remote-sensing Infrared Exoplanet Large-survey missions.
This paper reports on the results of time resolution measurements of Multigap Resistive Plate Chamber (MRPC). Three 20 gas gaps MRPCs were built with thin float glass sheets and different gap sizes: ...160μm, 140μm and 120μm. These chambers have been tested using a different gas flow configurations. The measurements indicate that to reach a better time resolution for small gap size (140μm and 120μm), a smaller gas volume of the chamber is preferable. The efficiency of the chambers in both gas flow configurations has been tested. A time resolution of 25 ps comprehensive of the front-end electronics jitter, with an efficiency of 98% has been achieved for the MRPC with 140μm gas gaps; this is the best time resolution. Moreover, all the chambers have been tested for different particle flux. At the highest particle flux tested, a time resolution better than 60 ps together with an efficiency higher than 80% has been achieved for all the detectors at an instantaneous particle flux of 30 kHz∕cm2. From the efficiency and time resolution study, the rate capability for these three MRPC is similar.
We report here on a UV-camera based field experiment performed on Stromboli volcano during 7 days in 2010 and 2011, aimed at obtaining the very first simultaneous assessment of all the different ...forms (passive and active) of SO2 release from an open-vent volcano. Using the unprecedented spatial and temporal resolution of the UV camera, we obtained a 0.8Hz record of the total SO2 flux from Stromboli over a timeframe of ∼14h, which ranged between 0.4 and 1.9kgs−1 around a mean value of 0.7kgs−1 and we concurrently derived SO2 masses for more than 130 Strombolian explosions and 50 gas puffs. From this, we show erupted SO2 masses have a variability of up to one order of magnitude, and range between 2 and 55kg (average ∼20kg), corresponding to a time integrated flux of 0.05±0.01kgs−1. Our experimental constraints on individual gas puff mass (0.03–0.42kg of SO2, averaging 0.19kg) are the first of their kind, equating to an emission rate ranging from 0.02 to 0.27kgs−1. On this basis, we conclude that puffing is two times more efficient than Strombolian explosions in the magmatic degassing process, and that active degassing (explosions+puffing) accounts for ∼23% (ranging from 10% to 45%) of the volcano's total SO2 flux, e.g., passive degassing between the explosions contributes the majority (∼77%) of the released gas. We furthermore integrate our UV camera gas data for the explosions and puffs, with independent geophysical data (infrared radiometer data and very long period seismicity), to offer key and novel insights into the degassing dynamics within the shallow conduit systems of this open-vent volcano.
► High spatial and temporal resolution UV-camera measurement performed on Stromboli. ► First assessment of all the different forms of SO2 release from a volcano. ► Explosive Strombolian activity contributes to 7±1.5% of the total SO2 flux. ► Puffing release twice more SO2 than Strombolian explosions. ► Explosion and puffing play a key role in modulating a cyclic SO2 degassing behaviour.
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