1,338 research outputs found
A Novel Method for Epileptic Seizure Detection Using Coupled Hidden Markov Models
We propose a novel Coupled Hidden Markov Model to detect epileptic seizures
in multichannel electroencephalography (EEG) data. Our model defines a network
of seizure propagation paths to capture both the temporal and spatial evolution
of epileptic activity. To address the intractability introduced by the coupled
interactions, we derive a variational inference procedure to efficiently infer
the seizure evolution from spectral patterns in the EEG data. We validate our
model on EEG aquired under clinical conditions in the Epilepsy Monitoring Unit
of the Johns Hopkins Hospital. Using 5-fold cross validation, we demonstrate
that our model outperforms three baseline approaches which rely on a classical
detection framework. Our model also demonstrates the potential to localize
seizure onset zones in focal epilepsy.Comment: To appear in MICCAI 2018 Proceeding
Transmission resonance spectroscopy in the third minimum of 232Pa
The fission probability of 232Pa was measured as a function of the excitation
energy in order to search for hyperdeformed (HD) transmission resonances using
the (d,pf) transfer reaction on a radioactive 231Pa target. The experiment was
performed at the Tandem accelerator of the Maier-Leibnitz Laboratory (MLL) at
Garching using the 231Pa(d,pf) reaction at a bombarding energy of E=12 MeV and
with an energy resolution of dE=5.5 keV. Two groups of transmission resonances
have been observed at excitation energies of E=5.7 and 5.9 MeV. The fine
structure of the resonance group at E=5.7 MeV could be interpreted as
overlapping rotational bands with a rotational parameter characteristic to a HD
nuclear shape. The fission barrier parameters of 232Pa have been determined by
fitting TALYS 1.2 nuclear reaction code calculations to the overall structure
of the fission probability. From the average level spacing of the J=4 states,
the excitation energy of the ground state of the 3rd minimum has been deduced
to be E(III)=5.05 MeV.Comment: 6 pages, 8 figure
Observation of Anomalous Internal Pair Creation in Be: A Possible Signature of a Light, Neutral Boson
Electron-positron angular correlations were measured for the isovector
magnetic dipole 17.6 MeV state (, ) ground state
(, ) and the isoscalar magnetic dipole 18.15 MeV (,
) state ground state transitions in Be. Significant
deviation from the internal pair creation was observed at large angles in the
angular correlation for the isoscalar transition with a confidence level of . This observation might indicate that, in an intermediate step, a
neutral isoscalar particle with a mass of 16.70 (stat)
(sys) MeV and was created.Comment: 5 pages, 5 figure
Synthesis, physico-chemical characterization and bacteriostatic study of Pt complexes with substituted amine ligands
Three complexes of general formula PtCl2R2 were synthesized, where R is the amine ligand with aromatic substituents. Coordination compounds [Pt(an)2Cl2] (1), [Pt(pa)2Cl2] (2) and [Pt(aph)2Cl2] (3), where an = 2-aminonaphthalene, pa = 2-aminopyrimidine, aph = 4-anilinophenol, were characterized by on-line coupled TG/DTA-MS, powder XRD and spectroscopic techniques (FTIR, ESI–MS and NMR), and tested against selected Gram(+) and Gram(–) bacteria. The thermal data show that all three compounds contain lattice or absorbed water, and the stability of the anhydrous compounds in nitrogen decreases in the order 2 > 1 > 3. Above 200 °C, the complexes loose characteristic fragments of their ligands. The spectroscopic data are in accordance with the thermal properties of the samples and prove their composition. The compounds are more effective inhibitors of Gram(+) than Gram(−) bacteria. © 2016 Akadémiai Kiadó, Budapest, Hungar
Proton decay from the isoscalar giant dipole resonance in Ni
Proton decay from the 3 isoscalar giant dipole resonance (ISGDR)
in Ni has been measured using the () reaction at a
bombarding energy of 386 MeV to investigate its decay properties. We have
extracted the ISGDR strength under the coincidence condition between
inelastically scattered particles at forward angles and decay protons
emitted at backward angles. Branching ratios for proton decay to low-lying
states of Co have been determined, and the results compared to
predictions of recent continuum-RPA calculations. The final-state spectra of
protons decaying to the low-lying states in Co were analyzed for a more
detailed understanding of the structure of the ISGDR. It is found that there
are differences in the structure of the ISGDR as a function of excitation
energy.Comment: Minor changes after review. Accepted for publication in Phys. Rev. C.
19 pages; 7 figure
Characterization and Performance of PADME's Cherenkov-Based Small-Angle Calorimeter
The PADME experiment, at the Laboratori Nazionali di Frascati (LNF), in
Italy, will search for invisible decays of the hypothetical dark photon via the
process , where the escapes detection. The
dark photon mass range sensitivity in a first phase will be 1 to 24 MeV. We
report here on measurement and simulation studies of the performance of the
Small-Angle Calorimeter, a component of PADME's detector dedicated to rejecting
2- and 3-gamma backgrounds. The crucial requirement is a timing resolution of
less than 200 ps, which is satisfied by the choice of PbF crystals and the
newly released Hamamatsu R13478UV photomultiplier tubes (PMTs). We find a
timing resolution of 81 ps (with double-peak separation resolution of 1.8 ns)
and a single-crystal energy resolution of 5.7%/ with light yield of
2.07 photo-electrons per MeV, using 100 to 400 MeV electrons at the Beam Test
Facility of LNF. We also propose the investigation of a two-PMT solution
coupled to a single PbF crystal for higher-energy applications, which has
potentially attractive features.Comment: 12 pages, 19 figures. v2: added section on radiation damage studie
Systematic investigation of the elastic proton-deuteron differential cross section at intermediate energies
To investigate the importance of three-nucleon forces (3NF) systematically
over a broad range of intermediate energies, the differential cross sections of
elastic proton-deuteron scattering have been measured at proton bombarding
energies of 108, 120, 135, 150, 170 and 190 MeV at center-of-mass angles
between and . Comparisons with Faddeev calculations show
unambiguously the shortcomings of calculations employing only two-body forces
and the necessity of including 3NF. They also show the limitations of the
latest few-nucleon calculations at backward angles, especially at higher beam
energies. Some of these discrepancies could be partially due to relativistic
effects. Data at lowest energy are also compared with a recent calculation
based on \chipt
Attention and speech-processing related functional brain networks activated in a multi-speaker environment
Human listeners can focus on one speech stream out of several concurrent ones. The present study aimed to assess the whole-brain functional networks underlying a) the process of focusing attention on a single speech stream vs. dividing attention between two streams and 2) speech processing on different time-scales and depth. Two spoken narratives were presented simultaneously while listeners were instructed to a) track and memorize the contents of a speech stream and b) detect the presence of numerals or syntactic violations in the same (“focused attended condition”) or in the parallel stream (“divided attended condition”). Speech content tracking was found to be associated with stronger connectivity in lower frequency bands (delta band- 0,5–4 Hz), whereas the detection tasks were linked with networks operating in the faster alpha (8–10 Hz) and beta (13–30 Hz) bands. These results suggest that the oscillation frequencies of the dominant brain networks during speech processing may be related to the duration of the time window within which information is integrated. We also found that focusing attention on a single speaker compared to dividing attention between two concurrent speakers was predominantly associated with connections involving the frontal cortices in the delta (0.5–4 Hz), alpha (8–10 Hz), and beta bands (13–30 Hz), whereas dividing attention between two parallel speech streams was linked with stronger connectivity involving the parietal cortices in the delta and beta frequency bands. Overall, connections strengthened by focused attention may reflect control over information selection, whereas connections strengthened by divided attention may reflect the need for maintaining two streams in parallel and the related control processes necessary for performing the tasks.</div
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