5,205 research outputs found
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Solo Voice Detection Via Optimal Cancellation
Automatically identifying sections of solo voices or instruments within a large corpus of music recordings would be useful, for example, to construct a library of isolated instruments to train signal models. We consider several ways to identify these sections, including a baseline classifier trained on conventional speech features. Our best results, achieving frame level precision and recall of around 70%, come from an approach that attempts to track the local periodicity of an assumed solo musical voice, then classifies the segment as a genuine solo or not on the basis of what proportion of the energy can be canceled by a comb filter constructed to remove just that periodicity
Validation of online psychometric instruments for common mental health disorders: a systematic review
Time scales in nuclear giant resonances
We propose a general approach to characterise fluctuations of measured cross
sections of nuclear giant resonances. Simulated cross sections are obtained
from a particular, yet representative self-energy which contains all
information about fragmentations. Using a wavelet analysis, we demonstrate the
extraction of time scales of cascading decays into configurations of different
complexity of the resonance. We argue that the spreading widths of collective
excitations in nuclei are determined by the number of fragmentations as seen in
the power spectrum. An analytic treatment of the wavelet analysis using a
Fourier expansion of the cross section confirms this principle. A simple rule
for the relative life times of states associated with hierarchies of different
complexity is given.Comment: 5 pages, 4 figure
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Calibration and assessment of process-based numerical models for beach profile evolution in southern California
Lattice QCD with Ginsparg-Wilson fermions
Lattice QCD using fermions whose Dirac operator obeys the Ginsparg-Wilson
relation, is perhaps the best known formulation of QCD with a finite cutoff. It
reproduces all the low energy QCD phenomenology associated with chiral symmetry
at finite lattice spacings. In particular it explains the origin of massless
pions due to spontaneous chiral symmetry breaking and leads to new ways to
approach the U(1) problem on the lattice. Here we show these results in the
path integral formulation and derive for the first time in lattice QCD a known
formal continuum relation between the chiral condensate and the topological
susceptibility. This relation leads to predictions for the critical behavior of
the topological susceptibility near the phase transition and can now be checked
in Monte-Carlo simulations even at finite lattice spacings.Comment: 6 pages, REVTEX. Added a new section on the critical behavior of the
zero modes near T_c with various flavors. This version will appear in Phys.
Rev.
A Spectroscopic Redshift Measurement for a Luminous Lyman Break Galaxy at z=7.730 using Keck/MOSFIRE
We present a spectroscopic redshift measurement of a very bright Lyman break
galaxy at z=7.7302+-0.0006 using Keck/MOSFIRE. The source was pre-selected
photometrically in the EGS field as a robust z~8 candidate with H=25.0 mag
based on optical non-detections and a very red Spitzer/IRAC [3.6]-[4.5]
broad-band color driven by high equivalent width [OIII]+Hbeta line emission.
The Lyalpha line is reliably detected at 6.1 sigma and shows an asymmetric
profile as expected for a galaxy embedded in a relatively neutral
inter-galactic medium near the Planck peak of cosmic reionization. The line has
a rest-frame equivalent width of EW0=21+-4 A and is extended with
V_FWHM=360+90-70 km/s. The source is perhaps the brightest and most massive z~8
Lyman break galaxy in the full CANDELS and BoRG/HIPPIES surveys, having
assembled already 10^(9.9+-0.2) M_sol of stars at only 650 Myr after the Big
Bang. The spectroscopic redshift measurement sets a new redshift record for
galaxies. This enables reliable constraints on the stellar mass, star-formation
rate, formation epoch, as well as combined [OIII]+Hbeta line equivalent widths.
The redshift confirms that the IRAC [4.5] photometry is very likely dominated
by line emission with EW0(OIII+Hbeta)= 720-150+180 A. This detection thus adds
to the evidence that extreme rest-frame optical emission lines are a ubiquitous
feature of early galaxies promising very efficient spectroscopic follow-up in
the future with infrared spectroscopy using JWST and, later, ELTs.Comment: 6 pages, 4 figures, small updates to match ApJL accepted versio
Effect of helium pre- or postconditioning on signal transduction kinases in patients undergoing coronary artery bypass graft surgery
Background: The noble gas helium induces pre- and postconditioning in animals and humans. Volatile anesthetics induce cardioprotection in humans undergoing coronary artery bypass graft (CABG) surgery. We hypothesized that helium induces pre-and postconditioning in CABG-patients, affecting signaling molecules protein kinase C-epsilon (PKC-epsilon), p38 mitogen activated protein kinase (p38 MAPK), extracellular signal-regulated kinase 1/2 (ERK-1/2) and heat shock protein 27 (HSP-27) within cardiac tissue, and reducing postoperative troponin levels.
Methods: After ethical approval and informed consent, 125 elective patients undergoing CABG surgery were randomised into this prospective, placebo controlled, investigator blinded, parallel arm single-centre study. Helium preconditioning (3 x 5 min of 70 % helium and 30 % oxygen) was applied before aortic cross clamping; postconditioning (15 min of helium) was applied before release of the aortic cross clamp. Signaling molecules were measured in right atrial appendix specimens. Troponin-T was measured at 4, 12, 24 and 48 h postoperatively.
Results: Baseline characteristics of all groups were similar. Helium preconditioning did not significantly alter the primary outcome (molecular levels of kinases PKC-e and HSP-27, ratio of activated p38 MAPK or ERK 1/2). Postoperative troponin T was 11 arbitrary units [5, 31; area-under-the-curve (interquartile range)] for controls, and no statistically significant changes were observed after helium preconditioning [He-pre: 11 (6, 18)], helium postconditioning [He-post: 11 (8, 15)], helium pre-and postconditioning [He-PP: 14 (6, 20)] and after sevoflurane preconditioning [APC: 12 (8, 24), p = 0.13]. No adverse effects related to study treatment were observed in this study.
Conclusions: No effect was observed of helium preconditioning, postconditioning or the combination thereof on activation of p38 MAPK, ERK 1/2 or levels of HSP27 and PKC-e in the human heart. Helium pre-and postconditioning did not affect postoperative troponin release in patients undergoing CABG surgery
Anomalous Hall Effect and Skyrmion Number in Real- and Momentum-space
We study the anomalous Hall effect (AHE) for the double exchange model with
the exchange coupling being smaller than the bandwidth for the
purpose of clarifying the following unresolved and confusing issues: (i) the
effect of the underlying lattice structure, (ii) the relation between AHE and
the skyrmion number, (iii) the duality between real and momentum spaces, and
(iv) the role of the disorder scatterings; which is more essential,
(Hall conductivity) or (Hall resistivity)? Starting from a generic
expression for , we resolve all these issues and classify the regimes
in the parameter space of (: elastic-scattering time), and
(length scale of spin texture). There are two distinct mechanisms
of AHE; one is characterized by the real-space skyrmion-number, and the other
by momentum-space skyrmion-density at the Fermi level, which work in different
regimes of the parameter space.Comment: 4 pages, 1 figure, REVTe
Electrical transport properties of bulk NiFe alloys and related spin-valve systems
Within the Kubo-Greenwood formalism we use the fully relativistic,
spin-polarized, screened Korringa-Kohn-Rostoker method together with the
coherent-potential approximation for layered systems to calculate the
resistivity for the permalloy series NiFe. We are able to
reproduce the variation of the resistivity across the entire series; notably
the discontinuous behavior in the vicinity of the structural phase transition
from bcc to fcc. The absolute values for the resistivity are within a factor of
two of the experimental data. Also the giant magnetoresistance of a series of
permalloy-based spin-valve structures is estimated; we are able to reproduce
the trends and values observed on prototypical spin-valve structures.Comment: 6 pages, ReVTeX + 4 figures (Encapsulated Postscript), submitted to
PR
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