1,216 research outputs found
In search of oculomotor capture during film viewing: implications for the balance of top-down and bottom-up control in the saccadic system
In the laboratory, the abrupt onset of a visual distractor can generate an involuntary orienting
response: this robust oculomotor capture effect has been reported in a large number of studies
(e.g. Theeuwes, Kramer, Hahn, & Irwin, 1998; Ludwig & Gilchrist, 2002) suggesting it may
be a ubiquitous part of more natural visual behaviour. However the visual stimuli used in
these experiments have tended to be static and had none of the complexity, and dynamism of
more natural visual environments. In addition, the primary task in the laboratory (typically
visual search) can be tedious for the participants with participant’s losing interest and
becoming stimulus driven and more easily distracted. Both of these factors may have led to
an overestimation of the extent to which oculomotor capture occurs and the importance of
this phenomena in everyday visual behaviour. To address this issue, in the current series of
studies we presented abrupt and highly salient visual distractors away from fixation while
participants watched a film. No evidence of oculomotor capture was found. However, the
distractor does effect fixation duration: we find an increase in fixation duration analogous to
the remote distractor effect (Walker, Deubel, & Schneider & Findlay, 1997). These results
suggest that during dynamic scene perception, the oculomotor system may be under far more
top-down control than traditional laboratory based-tasks have previously suggested
Prevention conference VII : Obesity, a worldwide epidemic related to heart disease and stroke : Group III: worldwide comorbidities of obesity
Astrophysical Tests of Modified Gravity: A Screening Map of the Nearby Universe
Astrophysical tests of modified modified gravity theories in the nearby
universe have been emphasized recently by Hui, Nicolis and Stubbs (2009) and
Jain and VanderPlas (2011). A key element of such tests is the screening
mechanism whereby general relativity is restored in massive halos or high
density environments like the Milky Way. In chameleon theories of gravity,
including all f(R) models, field dwarf galaxies may be unscreened and therefore
feel an extra force, as opposed to screened galaxies. The first step to study
differences between screened and unscreened galaxies is to create a 3D
screening map. We use N-body simulations to test and calibrate simple
approximations to determine the level of screening in galaxy catalogs. Sources
of systematic errors in the screening map due to observational inaccuracies are
modeled and their contamination is estimated. We then apply our methods to
create a map out to 200 Mpc in the Sloan Digital Sky Survey footprint using
data from the Sloan survey and other sources. In two companion papers this map
will be used to carry out new tests of gravity using distance indicators and
the disks of dwarf galaxies. We also make our screening map publicly available.Comment: 21 pages, 10 figure
Influence of the 6^1S_0-6^3P_1 Resonance on Continuous Lyman-alpha Generation in Mercury
Continuous coherent radiation in the vacuum-ultraviolet at 122 nm
(Lyman-alpha) can be generated using sum-frequency mixing of three fundamental
laser beams in mercury vapour. One of the fundamental beams is at 254 nm
wavelength, which is close to the 6^1S_0-6^3P_1 resonance in mercury.
Experiments have been performed to investigate the effect of this one-photon
resonance on phasematching, absorption and the nonlinear yield. The efficiency
of continuous Lyman-alpha generation has been improved by a factor of 4.5.Comment: 8 pages, 7 figure
Punctuated equilibria and 1/f noise in a biological coevolution model with individual-based dynamics
We present a study by linear stability analysis and large-scale Monte Carlo
simulations of a simple model of biological coevolution. Selection is provided
through a reproduction probability that contains quenched, random interspecies
interactions, while genetic variation is provided through a low mutation rate.
Both selection and mutation act on individual organisms. Consistent with some
current theories of macroevolutionary dynamics, the model displays
intermittent, statistically self-similar behavior with punctuated equilibria.
The probability density for the lifetimes of ecological communities is well
approximated by a power law with exponent near -2, and the corresponding power
spectral densities show 1/f noise (flicker noise) over several decades. The
long-lived communities (quasi-steady states) consist of a relatively small
number of mutualistically interacting species, and they are surrounded by a
``protection zone'' of closely related genotypes that have a very low
probability of invading the resident community. The extent of the protection
zone affects the stability of the community in a way analogous to the height of
the free-energy barrier surrounding a metastable state in a physical system.
Measures of biological diversity are on average stationary with no discernible
trends, even over our very long simulation runs of approximately 3.4x10^7
generations.Comment: 20 pages RevTex. Minor revisions consistent with published versio
Molecular Mechanism of the Constitutive Activation of the L250Q Human Melanocortin-4 Receptor Polymorphism â€
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65471/1/j.1747-0285.2006.00362.x.pd
Nuclear transparency from quasielastic A(e,e'p) reactions uo to Q^2=8.1 (GeV/c)^2
The quasielastic (e,ep) reaction was studied on targets of
deuterium, carbon, and iron up to a value of momentum transfer of 8.1
(GeV/c). A nuclear transparency was determined by comparing the data to
calculations in the Plane-Wave Impulse Approximation. The dependence of the
nuclear transparency on and the mass number was investigated in a
search for the onset of the Color Transparency phenomenon. We find no evidence
for the onset of Color Transparency within our range of . A fit to the
world's nuclear transparency data reflects the energy dependence of the free
proton-nucleon cross section.Comment: 11 pages, 6 figure
The PHENIX Experiment at RHIC
The physics emphases of the PHENIX collaboration and the design and current
status of the PHENIX detector are discussed. The plan of the collaboration for
making the most effective use of the available luminosity in the first years of
RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program
available at http://www.rhic.bnl.gov/phenix
Beyond the Shade of the Oak Tree: The Recent Growth of Johannine Studies
The recent growth within Johannine studies has developed as a result of several factors. First, the discovery of the Dead Sea Scrolls led to an appreciation of the Jewishness of John’s origin. Second, new approaches to John’s composition have emerged, followed by a larger set of inquiries as to the Johannine tradition’s relation to parallel traditions. This has been accompanied by a fourth interest: the history of the Johannine situation. Fifth, new literary studies have posed new horizons for interpretation, and sixth, theories continue to abound on the identity of the Beloved Disciple. A seventh development involves new ways of conceiving John’s theological features, leading to an eighth: reconsidering John’s historical features and re-envisioning its historical contributions in new perspective
Conceptual framework for an episode of rehabilitative care after hip fracture surgery
Researchers face a challenge when evaluating the effectiveness of rehabilitation after hip fracture surgery. Reported outcomes of rehabilitation will vary depending on the endpoint of the episode of care. Evaluation at an inappropriate endpoint may suggest a lack of effectiveness leading to the underuse of rehabilitation that could improve outcomes. The purpose of this paper is to describe a conceptual framework for a continuum-care-episode of rehabilitation after hip fracture surgery. We propose definitions for the index event, endpoint, and service scope of the episode. We discuss challenges in defining the episode of care, operationalizing the episode, and next steps for researchers. The episode described is intended to apply to all patients eligible for entry to rehabilitation after hip fracture and includes most functional recovery endpoints. This framework will provide a guide for rehabilitation researchers when designing and interpreting evaluations of the effectiveness of rehabilitation after hip fracture. Evaluation of all potential care episodes facilitates transparency in reporting of outcomes enabling researchers to determine the true effectiveness of rehabilitation after hip fracture surgery
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