2,667 research outputs found
Listen, Learn, Like! Dorsolateral Prefrontal Cortex Involved in the Mere Exposure Effect in Music
We used functional magnetic resonance imaging to investigate the neural basis of the mere exposure effect in music listening, which links previous exposure to liking. Prior to scanning, participants underwent a learning phase, where exposure to melodies was systematically varied. During scanning, participants rated liking for each melody and, later, their recognition of them. Participants showed learning effects, better recognising melodies heard more often. Melodies heard most often were most liked, consistent with the mere exposure effect. We found neural activations as a function of previous exposure in bilateral dorsolateral prefrontal and inferior parietal cortex, probably reflecting retrieval and working memory-related processes. This was despite the fact that the task during scanning was to judge liking, not recognition, thus suggesting that appreciation of music relies strongly on memory processes. Subjective liking per se caused differential activation in the left hemisphere, of the anterior insula, the caudate nucleus, and the putamen
Computational depth complexity of measurement-based quantum computation
We prove that one-way quantum computations have the same computational power
as quantum circuits with unbounded fan-out. It demonstrates that the one-way
model is not only one of the most promising models of physical realisation, but
also a very powerful model of quantum computation. It confirms and completes
previous results which have pointed out, for some specific problems, a depth
separation between the one-way model and the quantum circuit model. Since
one-way model has the same computational power as unbounded quantum fan-out
circuits, the quantum Fourier transform can be approximated in constant depth
in the one-way model, and thus the factorisation can be done by a polytime
probabilistic classical algorithm which has access to a constant-depth one-way
quantum computer. The extra power of the one-way model, comparing with the
quantum circuit model, comes from its classical-quantum hybrid nature. We show
that this extra power is reduced to the capability to perform unbounded
classical parity gates in constant depth.Comment: 12 page
Highly ionized Fe K emission lines from the LINER galaxy M 81
We present spectral and timing results from a long (130 ks) XMM-NEWTON EPIC
observation of the nucleus of the Seyfert/LINER galaxy M 81. During the
observation the X-ray flux varied by 20%, but there was no significant change
in spectral shape. The 2-10 keV spectrum is well described by a power law
continuum and three narrow Fe K emission lines at 6.4, 6.7 and 6.96 keV. The
three emission lines have equivalent widths of 39, 47, and 37 eV respectively.
The ratios of the three lines are thus more similar to those observed from the
Galactic Centre region than to those typically observed from Seyfert galaxies.
The high ionization lines most likely originate either from photoionized gas
within 0.1 pc of the nucleus of M 81, or from a non-thermal distribution of
cosmic-ray electrons interacting with the 0.2-0.6 keV thermal plasma which is
found in the bulge of M 81.Comment: Accepted for publication in A&
On the absorption of X-ray bright broad absorption line quasars
Most X-ray studies of BALQSOs found significant (N_H~10^{22-24} cm^{-2})
intrinsic column densities of gas absorbing an underlying typical power-law
continuum emission, in agreement with expectations from radiatively driven
accretion disk wind models. However, direct spectral analysis was performed
only on a limited number of bright sources. We investigate the X-ray emission
of a large BALQSO sample at medium to high redshift (0.8<z<3.7), drawn from the
cross-correlation of SDSS DR5 and 2XMM catalogs. We perform on it
moderate-quality X-ray spectral and hardness ratio analysis, and X-ray/optical
photometry. No or little intrinsic X-ray neutral absorption is found for one
third of the spectroscopically analyzed BALQSO sample (N_H < 4 x 10^{21}
cm^{-2} at 90% confidence level), and lower than typical X-ray absorption is
found in the remaining sources ( ~ 5 x 10^{22} cm^{-2}) even including the
faintest sources analyzed through hardness ratio analysis. The mean photon
index is Gamma~1.9, with no significant evolution with redshift. The alpha_ox
are typical of radio-quiet broad line AGN, in contrast with the known (from
previous X-ray studies) ``soft X-ray weakness'' of BALQSOs and in agreement
with the lack of X-ray absorption. We found the low-Absorption Index (AI)
subsample to host the lowest X-ray absorbing column densities of the entire
sample. X-ray selected BALQSOs show lower X-ray absorption than purely
optically selected ones, and soft X-ray weakness does not hold for any of them.
Their outflows may be launched by different mechanisms than classical soft
X-ray weak BALQSOs or they may be the tail of the already known population seen
along a different line of sight, in both cases expanding the observational
parameter space for their search and investigation.Comment: Accepted by A&A. 20 pages, 10 figures, 5 tables. Appendices available
in online edition. Typos corrected, two references added, improved figure
Genome-wide analyses for personality traits identify six genomic loci and show correlations with psychiatric disorders
Personality is influenced by genetic and environmental factors1
and associated with mental health. However, the underlying
genetic determinants are largely unknown. We identified six
genetic loci, including five novel loci2,3, significantly associated
with personality traits in a meta-analysis of genome-wide
association studies (N = 123,132–260,861). Of these genomewide
significant loci, extraversion was associated with variants
in WSCD2 and near PCDH15, and neuroticism with variants
on chromosome 8p23.1 and in L3MBTL2. We performed a
principal component analysis to extract major dimensions
underlying genetic variations among five personality traits
and six psychiatric disorders (N = 5,422–18,759). The first
genetic dimension separated personality traits and psychiatric
disorders, except that neuroticism and openness to experience
were clustered with the disorders. High genetic correlations
were found between extraversion and attention-deficit–
hyperactivity disorder (ADHD) and between openness and
schizophrenia and bipolar disorder. The second genetic
dimension was closely aligned with extraversion–introversion
and grouped neuroticism with internalizing psychopathology
(e.g., depression or anxiety)
The landscape of Neandertal ancestry in present-day humans
Analyses of Neandertal genomes have revealed that Neandertals have contributed genetic variants to modern humans1–2. The antiquity of Neandertal gene flow into modern humans means that regions that derive from Neandertals in any one human today are usually less than a hundred kilobases in size. However, Neandertal haplotypes are also distinctive enough that several studies have been able to detect Neandertal ancestry at specific loci1,3–8. Here, we have systematically inferred Neandertal haplotypes in the genomes of 1,004 present-day humans12. Regions that harbor a high frequency of Neandertal alleles in modern humans are enriched for genes affecting keratin filaments suggesting that Neandertal alleles may have helped modern humans adapt to non-African environments. Neandertal alleles also continue to shape human biology, as we identify multiple Neandertal-derived alleles that confer risk for disease. We also identify regions of millions of base pairs that are nearly devoid of Neandertal ancestry and enriched in genes, implying selection to remove genetic material derived from Neandertals. Neandertal ancestry is significantly reduced in genes specifically expressed in testis, and there is an approximately 5-fold reduction of Neandertal ancestry on chromosome X, which is known to harbor a disproportionate fraction of male hybrid sterility genes20–22. These results suggest that part of the reduction in Neandertal ancestry near genes is due to Neandertal alleles that reduced fertility in males when moved to a modern human genetic background
Grain Surface Models and Data for Astrochemistry
AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of ∼25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions
Standalone vertex finding in the ATLAS muon spectrometer
A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
- …