3,951 research outputs found
Extended transition rates and lifetimes in Al I and Al II from systematic multiconfiguration calculations
Multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration
interaction (RCI) calculations were performed for 28 and 78 states in neutral
and singly ionized aluminium, respectively. In Al I, the configurations of
interest are for with to , as well as and
for . In Al II, the studied configurations are, besides the
ground configuration , with to and to , ,
, and . Valence and core-valence electron correlation
effects are systematically accounted for through large configuration state
function (CSF) expansions. Calculated excitation energies are found to be in
excellent agreement with experimental data from the NIST database. Lifetimes
and transition data for radiative electric dipole (E1) transitions are given
and compared with results from previous calculations and available
measurements, for both Al I and Al II. The computed lifetimes of Al I are in
very good agreement with the measured lifetimes in high-precision laser
spectroscopy experiments. The present calculations provide a substantial amount
of updated atomic data, including transition data in the infrared region. This
is particularly important since the new generation of telescopes are designed
for this region. There is a significant improvement in accuracy, in particular
for the more complex system of neutral Al I. The complete tables of transition
data are available
The modifier effect and property mutability
The modifier effect is the reduction in perceived likelihood of a generic property sentence, when the head noun is modified. We investigated the prediction that the modifier effect would be stronger for mutable than for central properties, without finding evidence for this predicted interaction over the course of five experiments. However Experiment 6, which provided a brief context for the modified concepts to lend them greater credibility, did reveal the predicted interaction. It is argued that the modifier effect arises primarily from a general lack of confidence in generic statements about the typical properties of unfamiliar concepts. Neither prototype nor classical models of concept combination receive support from the phenomenon
Dynamical breakdown of the Ising spin-glass order under a magnetic field
The dynamical magnetic properties of an Ising spin glass
FeMnTiO are studied under various magnetic fields. Having
determined the temperature and static field dependent relaxation time
from ac magnetization measurements under a dc bias field by a
general method, we first demonstrate that these data provide evidence for a
spin-glass (SG) phase transition only in zero field. We next argue that the
data of finite can be well interpreted by the droplet theory
which predicts the absence of a SG phase transition in finite fields.Comment: 4 pages, 5 figure
Light Interception and Dry Matter Yield in Grass/Legume Mixtures
The influence of grass variety on light interception and dry matter yield in a grass/clover mixture was studied. Two varieties of timothy (Phleum pratense L.) and five varieties of ryegrass (Lolium spp) as components in a mixture were compared during the spring period up to the first cut of the third harvest year. By replacing the timothy variety in the mixture both light interception and dry matter yield were significantly affected. The leaf orientation was thought to be a contributing factor with erect leaves intercepting less light. There were no significant differences neither in light interception nor in yield between the mixtures with different ryegrass varieties, not even between the earliest and the latest varieties being the two contrasts in light interception
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On prototypes as defaults (Comment on Connolly, Fodor, Gleitman and Gleitman, 2007)
Interaction effects and transport properties of Pt capped Co nanoparticles
We studied the magnetic and transport properties of Co nanoparticles (NPs)
being capped with varying amounts of Pt. Beside field and temperature dependent
magnetization measurements we performed delta-M measurements to study the
magnetic interactions between the Co NPs. We observe a transition from
demagnetizing towards magnetizing interactions between the particles for an
increasing amount of Pt capping. Resistivity measurements show a crossover from
giant magnetoresistance towards anisotropic magnetoresistance
Spin glass behavior in an interacting gamma-Fe2O3 nanoparticle system
In this paper we investigate the superspin glass behavior of a concentrated
assembly of interacting maghemite nanoparticles and compare it to that of
canonical atomic spin glass systems. ac versus temperature and frequency
measurements show evidence of a superspin glass transition taking place at low
temperature. In order to fully characterize the superspin glass phase, the
aging behavior of both the thermo-remanent magnetization (TRM) and ac
susceptibility has been investigated. It is shown that the scaling laws obeyed
by superspin glasses and atomic spin glasses are essentially the same, after
subtraction of a superparamagnetic contribution from the superspin glass
response functions. Finally, we discuss a possible origin of this
superparamagnetic contribution in terms of dilute spin glass models
Constraining dark matter halo properties using lensed SNLS supernovae
This paper exploits the gravitational magnification of SNe Ia to measure
properties of dark matter haloes. The magnification of individual SNe Ia can be
computed using observed properties of foreground galaxies and dark matter halo
models. We model the dark matter haloes of the galaxies as truncated singular
isothermal spheres with velocity dispersion and truncation radius obeying
luminosity dependent scaling laws. A homogeneously selected sample of 175 SNe
Ia from the first 3-years of the Supernova Legacy Survey (SNLS) in the redshift
range 0.2 < z < 1 is used to constrain models of the dark matter haloes
associated with foreground galaxies. The best-fitting velocity dispersion
scaling law agrees well with galaxy-galaxy lensing measurements. We further
find that the normalisation of the velocity dispersion of passive and star
forming galaxies are consistent with empirical Faber-Jackson and Tully-Fisher
relations, respectively. If we make no assumption on the normalisation of these
relations, we find that the data prefer gravitational lensing at the 92 per
cent confidence level. Using recent models of dust extinction we deduce that
the impact of this effect on our results is very small. We also investigate the
brightness scatter of SNe Ia due to gravitational lensing. The gravitational
lensing scatter is approximately proportional to the SN Ia redshift. We find
the constant of proportionality to be B = 0.055 +0.039 -0.041 mag (B < 0.12 mag
at the 95 per cent confidence level). If this model is correct, the
contribution from lensing to the intrinsic brightness scatter of SNe Ia is
small for the SNLS sample.Comment: 11 pages, 7 figures, accepted for publication in MNRA
Shifting foundations: the mechanical cell wall and development.
The cell wall has long been acknowledged as an important physical mediator of growth in plants. Recent experimental and modelling work has brought the importance of cell wall mechanics into the forefront again. These data have challenged existing dogmas that relate cell wall structure to cell/organ growth, that uncouple elasticity from extensibility, and those which treat the cell wall as a passive and non-stressed material. Within this review we describe experiments and models which have changed the ways in which we view the mechanical cell wall, leading to new hypotheses and research avenues. It has become increasingly apparent that while we often wish to simplify our systems, we now require more complex multi-scale experiments and models in order to gain further insight into growth mechanics. We are currently experiencing an exciting and challenging shift in the foundations of our understanding of cell wall mechanics in growth and development.Work in the authors’ groups is funded by The Gatsby Charitable Foundation (GAT3396/PR4, SB; GAT3395/PR4, HJ), the Swedish Research Council (VR2013‐4632, HJ), the Knut and Alice Wallenberg Foundation via ShapeSystems (HJ), and the BBSRC (BB.L002884.1, SB).This is the final version of the article. It first appeared from Elsevier via https://doi.org/10.1016/j.pbi.2015.12.00
Immersive Composition for Sensory Rehabilitation: 3D Visualisation, Surround Sound, and Synthesised Music to Provoke Catharsis and Healing
There is a wide range of sensory therapies using sound, music and visual stimuli. Some focus on soothing or distracting stimuli such as natural sounds or classical music as analgesic, while other approaches emphasize the
active performance of producing music as therapy. This paper proposes an immersive
multi-sensory Exposure Therapy for people suffering from anxiety disorders, based on a rich, detailed surround-soundscape. This soundscape is composed to include the users’ own idiosyncratic anxiety triggers as a form of
habituation, and to provoke psychological catharsis, as a non-verbal, visceral and enveloping exposure. To accurately pinpoint the most effective sounds and to optimally compose the soundscape we will monitor the participants’ physiological responses such as electroencephalography, respiration, electromyography, and heart rate during exposure. We hypothesize that such physiologically optimized sensory landscapes will aid the development of future immersive therapies for various psychological conditions, Sound is a major trigger of anxiety, and auditory hypersensitivity is an extremely problematic symptom. Exposure to stress-inducing sounds can free anxiety sufferers from entrenched avoidance behaviors, teaching physiological coping strategies and encouraging resolution of the psychological issues agitated by the sound
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