6,003 research outputs found
Perceptual aberrations impair mental own-body transformations
Dysfunctional self and bodily processing have been reported from the schizophrenia spectrum. Here, the authors tested 72 students (40 women) to determine whether performance in a mental own-body transformation task relates to self-rated frequency of spontaneously experienced schizotypal body schema alterations (perceptual aberration). Participants provided speeded left-right decisions concerning the body of a visually depicted human figure (front view vs. back view). For men, reaction times to disembodied perspectives increased with increasing scores on a validated perceptual aberration scale. This finding constitutes behavioral evidence for the clinically postulated association between aberrant bodily experiences during everyday life and aberrant processing in a mental own-body transformation task arguably reflecting mild dysfunction at the temporo-parietal junction
Three-dimensional Magnetic Resonance Imaging of fossils across taxa
The frequency of life forms in the fossil record is largely determined by the extent to which they were mineralised at the time of their death. In addition to mineral structures, many fossils nonetheless contain detectable amounts of residual water or organic molecules, the analysis of which has become an integral part of current palaeontological research. The methods available for this sort of investigations, though, typically require dissolution or ionisation of the fossil sample or parts thereof, which is an issue with rare taxa and outstanding materials like pathological or type specimens. In such cases, non-destructive techniques could provide a valuable methodological alternative. While Computed Tomography has long been used to study palaeontological specimens, a number of complementary approaches have recently gained ground. These include Magnetic Resonance Imaging (MRI) which had previously been employed to obtain three-dimensional images of pathological belemnites non-invasively on the basis of intrinsic contrast. The present study was undertaken to investigate whether <sup>1</sup>H MRI can likewise provide anatomical information about non-pathological belemnites and specimens of other fossil taxa. To this end, three-dimensional MR image series were acquired from intact non-pathological invertebrate, vertebrate and plant fossils. At routine voxel resolutions in the range of several dozens to some hundreds of micrometers, these images reveal a host of anatomical details and thus highlight the potential of MR techniques to effectively complement existing methodological approaches for palaeontological investigations in a wide range of taxa. As for the origin of the MR signal, relaxation and diffusion measurements as well as <sup>1</sup>H and <sup>13</sup>C MR spectra acquired from a belemnite suggest intracrystalline water or hydroxyl groups, rather than organic residues
Relativistic transition wavelenghts and probabilities for spectral lines of Ne II
Transition wavelengths and probabilities for several 2p4 3p - 2p4 3s and 2p4
3d - 2p4 3p lines in fuorine-like neon ion (NeII) have been calculated within
the multiconfiguration Dirac-Fock (MCDF) method with quantum electrodynamics
(QED) corrections. The results are compared with all existing experimental and
theoretical data
Relativistic and Radiative Energy Shifts for Rydberg States
We investigate relativistic and quantum electrodynamic effects for
highly-excited bound states in hydrogenlike systems (Rydberg states). In
particular, hydrogenic one-loop Bethe logarithms are calculated for all
circular states (l = n-1) in the range 20 <= n <= 60 and successfully compared
to an existing asymptotic expansion for large principal quantum number n. We
provide accurate expansions of the Bethe logarithm for large values of n, for
S, P and circular Rydberg states. These three expansions are expected to give
any Bethe logarithms for principal quantum number n > 20 to an accuracy of five
to seven decimal digits, within the specified manifolds of atomic states.
Within the numerical accuracy, the results constitute unified, general formulas
for quantum electrodynamic corrections whose validity is not restricted to a
single atomic state. The results are relevant for accurate predictions of
radiative shifts of Rydberg states and for the description of the recently
investigated laser-dressed Lamb shift, which is observable in a strong
coherent-wave light field.Comment: 8 pages; RevTeX
Insights into the O : C-dependent mechanisms controlling the evaporation of α-pinene secondary organic aerosol particles
The volatility of oxidation products of volatile organic
compounds (VOCs) in the atmosphere is a key factor to determine if they
partition into the particle phase contributing to secondary organic aerosol
(SOA) mass. Thus, linking volatility and measured particle composition will
provide insights into SOA formation and its fate in the atmosphere. We
produced α-pinene SOA with three different oxidation levels
(characterized by average oxygen-to-carbon ratio; O:C‾=0.53, 0.69, and 0.96) in an oxidation flow reactor. We investigated the
particle volatility by isothermal evaporation in clean air as a function of
relative humidity (RH <2 %, 40 %, and 80 %) and used a
filter-based thermal desorption method to gain volatility and chemical
composition information.
We observed reduced particle evaporation for particles with increasing
O:C‾ ratio, indicating that particles become more resilient to evaporation with
oxidative aging. Particle evaporation was increased in the presence of water
vapour and presumably particulate water; at the same time the resistance of
the residual particles to thermal desorption was increased as well. For SOA
with O:C‾=0.96, the unexpectedly large increase in mean thermal desorption
temperature and changes in the thermogram shapes under wet conditions
(80 % RH) were an indication of aqueous phase chemistry. For the lower
O:C‾ cases, some water-induced composition changes were observed. However, the
enhanced evaporation under wet conditions could be explained by the
reduction in particle viscosity from the semi-solid to liquid-like range, and
the observed higher desorption temperature of the residual particles is a
direct consequence of the increased removal of high-volatility and the
continued presence of low-volatility compounds.</p
Relativistic Calculation of two-Electron one-Photon and Hypersatellite Transition Energies for Elements
Energies of two-electron one-photon transitions from initial double K-hole
states were computed using the Dirac-Fock model. The transition energies of
competing processes, the K hypersatellites, were also computed. The
results are compared to experiment and to other theoretical calculations.Comment: accepted versio
The RMS Charge Radius of the Proton and Zemach Moments
On the basis of recent precise measurements of the electric form factor of
the proton, the Zemach moments, needed as input parameters for the
determination of the proton rms radius from the measurement of the Lamb shift
in muonic hydrogen, are calculated. It turns out that the new moments give an
uncertainty as large as the presently stated error of the recent Lamb shift
measurement of Pohl et al.. De Rujula's idea of a large Zemach moment in order
to reconcile the five standard deviation discrepancy between the muonic Lamb
shift determination and the result of electronic experiments is shown to be in
clear contradiction with experiment. Alternative explanations are touched upon.Comment: 6 pages, 4 figures, final version includes discussion of systematic
and numerical error
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Optimization of Calcine Blending During Retrieval From Binsets
This report documents a study performed during advanced feasibility studies for the INTEC Technology Development Facility (ITDF). The study was commissioned to provide information about functional requirements for the ITDF related to development of equipment and procedures for retrieving radioactive calcine from binset storage at the Idaho Nuclear Technology and Engineering Center (INTEC) at the Idaho National Engineering and Environmental Laboratory (INEEL). Calcine will be retrieved prior to treating it for permanent disposal in a national repository for high level waste. The objective this study was to estimate the degree of homogenization of the calcine that might be achieved through optimized retrieval and subsequent blending. Such homogenization has the potential of reducing the costs for treatment of the calcine and for qualifying of the final waste forms for acceptance at the repository. Results from the study indicate that optimized retrieval and blending can reduce the peak c oncentration variations of key components (Al, Zr, F) in blended batches of retrieved calcine. During un-optimized retrieval these variations are likely to be 81-138% while optimized retrieval can reduce them to the 5-10% range
Interpreting physical performance in professional soccer match-play: Should we be more pragmatic in our approach?
Academic and practitioner interest in the physical performance of male professional soccer players in the competition setting determined via time-motion analyses has grown substantially over the last four decades leading to a substantial body of published research and aiding development of a more systematic evidence-based framework for physical conditioning. Findings have forcibly shaped contemporary opinions in the sport with researchers and practitioners frequently emphasising the important role that physical performance plays in match outcomes. Time-motion analyses have also influenced practice as player conditioning programmes can be tailored according to the different physical demands identified across individual playing positions. Yet despite a more systematic approach to physical conditioning, data indicate that even at the very highest standards of competition, the contemporary player is still susceptible to transient and end-game fatigue. Over the course of this article, the author suggests that a more pragmatic approach to interpreting the current body of time-motion analysis data and its application in the practical setting is nevertheless required. Examples of this are addressed using findings in the literature to examine: a) the association between competitive physical performance and ‘success’ in professional soccer, b) current approaches to interpreting differences in time-motion analysis data across playing positions and, c) whether data can realistically be used to demonstrate the occurrence of fatigue in match-play. Gaps in the current literature and directions for future research are also identified
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