91,084 research outputs found
Probing expert anticipation with the temporal occlusion paradigm: Experimental investigations of some methodological issues
Copyright @ 2005 Human KineticsTwo experiments were conducted to examine whether the conclusions drawn regarding the timing of anticipatory information pick-up from temporal occlusion studies are influenced by whether (a) the viewing period is of variable or fixed duration and (b) the task is a laboratory-based one with simple responses or a natural one requiring a coupled, interceptive movement response. Skilled and novice tennis players either made pencil-and-paper predictions of service direction (Experiment 1) or attempted to hit return strokes (Experiment 2) to tennis serves while their vision was temporally occluded in either a traditional progressive mode (where more information was revealed in each subsequent occlusion condition) or a moving window mode (where the visual display was only available for a fixed duration with this window shifted to different phases of the service action). Conclusions regarding the timing of information pick-up were generally consistent across display mode and across task setting lending support to the veracity and generalisability of findings regarding perceptual expertise in existing laboratory-based progressive temporal occlusion studies.This study is funded by the Australian Institute of Sport Tennis program
Detection of coherent light in an incoherent background
The change in position of the self-coherence function minimum is used to detect the presence of a coherent source, rather than the change in strength of the self-coherence function at the reference path difference. The system uses both optical and digital signal processing with MATLAB algorithm. An experimental system was built in the visible band, employing a Michelson interferometer, an interference filter centered in the red, and a silicon photodetector. The results were averaged over up to 50 scans, depending on the relative visibility of the white light and laser fringes, to reduce the scan to scan variability. Amplifier gain was introduced to reduce quantization noise
Priming to promote fluent motor skill execution: Exploring attentional demands
The effect of priming on the speed and accuracy of skilled performance and on a probe-reaction time task designed to measure residual attentional capacity, was assessed. Twenty-four skilled soccer players completed a dribbling task under three prime conditions (fluency, skill-focus, and neutral) and a control condition. Results revealed changes in trial completion time and secondary task performance in line with successfully priming autonomous and skill-focused attention. Retention test data for task completion time and probe-reaction time indicated a linear decrease in the priming effect such that the effect was nonsignificant after 30 min. Results provide further support for the efficacy of priming and provide the first evidence of concurrent changes in attentional demands, consistent with promoting or disrupting automatic skill execution
Large-Scale Structures Behind the Milky Way from Near-IR Surveys
About 25% of the optical extragalactic sky is obscured by the dust and stars
of our Milky Way. Dynamically important structures might still lie hidden in
this zone. Various approaches are presently being employed to uncover the
galaxy distribution in the Zone of Avoidance (ZOA) but all suffer from
(different) limitations and selection effects.
We investigated the potential of using the DENIS NIR survey for studies of
galaxies behind the obscuration layer of our Milky Way and for mapping the
Galactic extinction. As a pilot study, we recovered DENIS I, J and K band
images of heavily obscured but optically still visible galaxies. We determined
the I, J and K band luminosity functions of galaxies on three DENIS strips that
cross the center of the nearby, low-latitude, rich cluster Abell 3627. The
extinction-corrected I-J and J-K colours of these cluster galaxies compare well
with that of an unobscured cluster. We searched for and identified galaxies at
latitudes where the Milky Way remains fully opaque (|b|
4-5mag) - in a systematic search as well as around positions of galaxies
detected with the blind HI survey of the ZOA currently conducted with the
Multibeam Receiver of the Parkes Radiotelescope.Comment: 12 pages, including 5 PS figures, LaTeX, uses crckapb.sty and
epsf.tex. Better resolved figures available upon request. To appear in
proceedings of the 3rd Euroconference (Meudon, France, June 1997) on ``The
Impact of Near IR Surveys'', Kluwer 199
VenSAR: A multi-functional S-band radar for the EnVision mission to Venus
The EnVision science case requires an instrument capable of providing global stereo images at 10-50 m resolution, phase information from at least 20% of the surface for interferometry, as well as the ability to provide 1-10 m resolution images of specific targets in the C- to S-band range (X-band does not penetrate through the atmosphere to the surface of Venus). VenSAR is adapted from the individual phase centre design of NovaSAR-S, which offers much greater flexibility that can be optimised for Venus science. In addition, its S-band wavelength offers an acceptable compromise between InSAR resolution and atmospheric stability. The use of an off-the-shelf system, adapted for use at Venus, saves cost and provides for directly comparable data from Venus and Earth at a resolution two orders of magnitude better than Magellan, for the first time allowing the direct measurement of rates of tectonic and volcanic processes on another planet
DISCOVERY OF RR LYRAE STARS IN THE NUCLEAR BULGE OF THE MILKY WAY
Indexación: Web of ScienceGalactic nuclei, such as that of the Milky Way, are extreme regions with high stellar densities, and in most cases, the hosts of a supermassive black hole. One of the scenarios proposed for the formation of the Galactic nucleus is merging of primordial globular clusters. An implication of this model is that this region should host stars that are characteristically found in old Milky Way globular clusters. RR Lyrae stars are primary distance indicators, well known representatives of old and metal-poor stellar populations, and therefore are regularly found in globular clusters. Here we report the discovery of a dozen RR Lyrae type ab stars in the vicinity of the Galactic center, i.e., in the so-called nuclear stellar bulge of the Milky Way. This discovery provides the first direct observational evidence that the Galactic nuclear stellar bulge contains ancient stars (>10 Gyr old). Based on this we conclude that merging globular clusters likely contributed to the build-up of the high stellar density in the nuclear stellar bulge of the Milky Way.http://iopscience.iop.org/article/10.3847/2041-8205/830/1/L14/meta;jsessionid=2531FBFFF06C9ECBA4852FB9D1F89851.c1.iopscience.cld.iop.or
The reality paradox: Authenticity, fidelity, and the real in Battlefield 4
This article examines how the ‘Battlefield’ (EA Games) series of games generates authenticity in its soundtrack both through a meticulous approach to modelling the physical world and through the appropriation of audio characteristics from our, typically mediated, experience of conflict. It goes on to examine how we might reconcile such ‘authentic’ audio with the more ludic features of the soundtrack, required to support gameplay, that are typically presented as inauthentic. The absence of these sounds during narrative-based sequences and the acceptance of them without negative impact on immersion during gameplay implies that these inauthentic sounds appear not to disrupt the immersive qualities of the ‘authentic’ but only when clearly positioned as ego-ludic (heard only by the player, non-spatialized and synthetic in quality) and only within the context of challenge-based sequences of the game
Robust estimation of stationary continuous-time ARMA models via indirect inference
In this paper we present a robust estimator for the parameters of a
continuous-time ARMA(p,q) (CARMA(p,q)) process sampled equidistantly which is
not necessarily Gaussian. Therefore, an indirect estimation procedure is used.
It is an indirect estimation because we first estimate the parameters of the
auxiliary AR(r) representation () of the sampled CARMA process
using a generalized M- (GM-)estimator. Since the map which maps the parameters
of the auxiliary AR(r) representation to the parameters of the CARMA process is
not given explicitly, a separate simulation part is necessary where the
parameters of the AR(r) representation are estimated from simulated CARMA
processes. Then, the parameter which takes the minimum distance between the
estimated AR parameters and the simulated AR parameters gives an estimator for
the CARMA parameters. First, we show that under some standard assumptions the
GM-estimator for the AR(r) parameters is consistent and asymptotically normally
distributed. Next, we prove that the indirect estimator is consistent and
asymptotically normally distributed as well using in the simulation part the
asymptotically normally distributed LS-estimator. The indirect estimator
satisfies several important robustness properties such as weak resistance,
-robustness and it has a bounded influence functional. The practical
applicability of our method is demonstrated through a simulation study with
replacement outliers and compared to the non-robust quasi-maximum-likelihood
estimation method
Option pricing in affine generalized Merton models
In this article we consider affine generalizations of the Merton jump
diffusion model [Merton, J. Fin. Econ., 1976] and the respective pricing of
European options. On the one hand, the Brownian motion part in the Merton model
may be generalized to a log-Heston model, and on the other hand, the jump part
may be generalized to an affine process with possibly state dependent jumps.
While the characteristic function of the log-Heston component is known in
closed form, the characteristic function of the second component may be unknown
explicitly. For the latter component we propose an approximation procedure
based on the method introduced in [Belomestny et al., J. Func. Anal., 2009]. We
conclude with some numerical examples
Multiplicity of fibronectin-binding alpha V integrin receptors in colorectal cancer.
Current data from in vitro and in vivo animal models indicate that fibronectin-binding integrin receptors expressed by colon cancer cells may regulate tumour growth. While individual members of the beta 1 subfamily of integrins have now been clearly identified in colorectal cancer, little information exists with respect to the alpha V subfamily. In the present study we show that alpha V can associate with multiple and different beta subunits capable of binding fibronectin in this tumour type. This is likely to have functional implications for growth and spread of colorectal cancer
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