23,055 research outputs found
Understanding the truth about subjectivity
Results of two experiments show children’s understanding of diversity in personal preference is incomplete. Despite acknowledging diversity, in Experiment 1(N=108), 6-
and 8-year-old children were less likely than adults to see preference as a legitimate basis for personal tastes and more likely to say a single truth could be found about a matter of taste. In Experiment 2 (N=96), 7- and 9-year-olds were less likely than 11- and 13-yearolds to say a dispute about a matter of preference might not be resolved. These data suggest that acceptance of the possibility of diversity does not indicate an adult-like understanding of subjectivity. An understanding of the relative emphasis placed on objective and subjective factors in different contexts continues to develop into adolescence
Spin Structure of the Nucleon - Status and Recent Results
After the initial discovery of the so-called "spin crisis in the parton
model" in the 1980's, a large set of polarization data in deep inelastic
lepton-nucleon scattering was collected at labs like SLAC, DESY and CERN. More
recently, new high precision data at large x and in the resonance region have
come from experiments at Jefferson Lab. These data, in combination with the
earlier ones, allow us to study in detail the polarized parton densities, the
Q^2 dependence of various moments of spin structure functions, the duality
between deep inelastic and resonance data, and the nucleon structure in the
valence quark region. Together with complementary data from HERMES, RHIC and
COMPASS, we can put new limits on the flavor decomposition and the gluon
contribution to the nucleon spin. In this report, we provide an overview of our
present knowledge of the nucleon spin structure and give an outlook on future
experiments. We focus in particular on the spin structure functions g_1 and g_2
of the nucleon and their moments.Comment: 69 pages, 46 figures. Report to be published in "Progress in Particle
and Nuclear Physics". v2 with added references and minor edit
Unifying metastasis--Integrating intravasation, circulation and end organ colonization
Recent technological advances that have enabled the measurement of circulating tumour cells (CTCs) in patients have spurred interest in the circulatory phase of metastasis. Techniques that do not solely rely on a blood sample allow substantial biological interrogation beyond simply counting CTCs
Kinetic Monte Carlo simulations of oscillatory shape evolution for electromigration-driven islands
The shape evolution of two-dimensional islands under electromigration-driven
periphery diffusion is studied by kinetic Monte Carlo (KMC) simulations and
continuum theory. The energetics of the KMC model is adapted to the Cu(100)
surface, and the continuum model is matched to the KMC model by a suitably
parametrized choice of the orientation-dependent step stiffness and step atom
mobility. At 700 K shape oscillations predicted by continuum theory are
quantitatively verified by the KMC simulations, while at 500 K qualitative
differences between the two modeling approaches are found.Comment: 7 pages, 6 figure
Diffusion and Interdiffusion in Binary Metallic Melts
We discuss the dependence of self- and interdiffusion coefficients on
temperature and composition for two prototypical binary metallic melts, Al-Ni
and Zr-Ni, in molecular-dynamics (MD) computer simulations and the
mode-coupling theory of the glass transition (MCT). Dynamical processes that
are mainly entropic in origin slow down mass transport (as expressed through
self diffusion) in the mixture as compared to the ideal-mixing contribution.
Interdiffusion of chemical species is a competition of slow kinetic modes with
a strong thermodynamic driving force that is caused by non-entropic
interactions. The combination of both dynamic and thermodynamic effects causes
qualitative differences in the concentration dependence of self-diffusion and
interdiffusion coefficients. At high temperatures, the thermodynamic
enhancement of interdiffusion prevails, while at low temperatures, kinetic
effects dominate the concentration dependence, rationalized within MCT as the
approach to its ideal-glass transition temperature . The Darken equation
relating self- and interdiffusion qualitatively reproduces the
concentration-dependence in both Zr-Ni and Al-Ni, but quantitatively, the
kinetic contributions to interdiffusion can be slower than the lower bound
suggested by the Darken equation. As temperature is decreased, the agreement
with Darken's equation improves, due to a strong coupling of all kinetic modes
that is a generic feature predicted by MCT.Comment: 16 pages, 12 figure
Determination of the Telluric Water Vapor Absorption Correction for Astronomical Data Obtained from the Kuiper Airborne Observatory
The amount of telluric water vapor along the line of sight of the Kuiper Airborne Observatory telescope as obtained concommitantly on 23 flights is compared with the NASA-Ames Michelson interferometer and with the NOAA-Boulder radiometer. A strong correlation between the two determinations exists, and a method for computing the atmospheric transmission for a given radiometer reading is established
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