37,722 research outputs found
Does priming really put the gloss on performance?
Priming has recently emerged in the literature as offering advantages in the preparation for skilled performance. Accordingly, the current study tested the efficacy of imagery against a priming paradigm as a means of enhancing motor performance: in essence, contrasting a preparation technique primarily under the conscious control of the performer to an unconscious technique promoting automaticity. The imagery intervention was guided by the PETTLEP model, while the priming intervention took the form of a scrambled sentence task. Eighteen skilled field-hockey players performed a dribbling task under imagery, priming, skill-focus, and control conditions. Results revealed a significant improvement in speed and technical accuracy for the imagery condition as opposed to the skill-focus, control, and priming conditions. In addition, there were no significant differences in performance times or technical accuracy between the priming and control conditions. The study provides further support for the efficacy of imagery to elicit enhanced motor skill performance but questions the emerging emphasis on priming as an effective tool in preparation for physical tasks
Applied sport psychology: Are we a profession?
Although the field of applied sport psychology has developed, it faces further challenges on its way towards gaining greater professional status. The following principal criteria of professionalism are proposed as a test of such status (Carr, 1999): (a) provide an important public service; (b) underpinning knowledge base; (c) organizational regulation; (d) distinct ethical dimension; and (e) professional autonomy. This paper undertakes to explore the nature of implications for practice and the extent to which the suggested principal criteria justify a distinctive applied sport psychology profession. In doing so, we hope to stimulate debate on these, and other issues, in order that an even greater professionalization of our applied discipline may emerge
Entangled maximal mixings in U_PMNS=U_l^dagger U_nu, and a connection to complex mass textures
We discuss two different configurations of U_PMNS=U_l^dagger U_nu with
maximal mixings in both U_l and U_nu. The non-maximal mixing angles are assumed
to be small, which means that they can be expanded in. Since we are
particularly interested in the implications for CP violation, we fully take
into account complex phases. We demonstrate that one possibility leads to
intrinsically large theta_13 and strong deviations from maximal mixings. The
other possibility is generically close to tri-bimaximal mixing, and allows for
large CP violation. We demonstrate how the determination of the theta_23 octant
and the precision measurement of delta_CP could discriminate among different
qualitative sub-cases. In order to constrain the unphysical and observable
phases even further, we relate our configurations to complex mass matrix
textures. In particular, we focus on phase patterns which could be generated by
powers of a single complex quantity eta=theta_C exp(i Phi), which can be
motivated by Froggatt-Nielsen-like models. For example, it turns out that in
all of the discussed cases, one of the Majorana phases is proportional to Phi
to leading order. In the entire study, we encounter three different classes of
sum rules, which we systematically classify.Comment: 27 pages, 6 tables, 1 figure. Shortened version to appear in Phys.
Rev.
High Efficiency Large Area Polysilicon Solar Cells
Large area (100 sq cm) polysilicon solar cells having efficiencies of up to 14.1% (100 mW/sq cm, 25 C) were fabricated and a detailed analysis was performed to identify the efficiency loss mechanisms. The 1-5 characteristics of the best cell were dominated by recombination in the quasi-neutral base due to the combination of minority carrier diffusion length and base resistivity. An analysis of the microstructural defects present in the material and their effect on the electrical properties is presented
Comparing SSN Index to X-ray Flare and Coronal Mass Ejection Rates from Solar Cycles 22-24
The newly revised sunspot number series allows for placing historical
geoeffective storms in the context of several hundred years of solar activity.
Using statistical analyses of the Geostationary Operational Environmental
Satellites (GOES) X-ray observations from the past ~30 years and the Solar and
Heliospheric Observatory (SOHO) Large Angle and Spectrometric Coronagraph
(LASCO) Coronal Mass Ejection (CME) catalog (1996-present), we present
sunspot-number-dependent flare and CME rates. In particular, we present X-ray
flare rates as a function of sunspot number for the past three cycles. We also
show that the 1-8 AA X-ray background flux is strongly correlated with sunspot
number across solar cycles. Similarly, we show that the CME properties (e.g.,
proxies related to the CME linear speed and width) are also correlated with
sunspot number for SC 23 and 24. These updated rates will enable future
predictions for geoeffective events and place historical storms in the context
of present solar activity.Comment: 17 pages, accepted to Solar Physic
Regeneration efficiency, shuttle heat loss and thermal conductivity in epoxy-composite annualr gap regenerators from 4K to 80K
A test apparatus designed to simulate a section of a Stirling cycle cryocooler was built. Measurements of regeneration efficiency, shuttle heat loss and thermal conductivity reported for several regenerator test sections. The test composites were epoxy glass, epoxy glass with lead particles, epoxy glass with activated charcoal and epoxy graphite. Losses measured for these materials were approximately the same. Losses are in good agreement with those calculated theoretically for an epoxy glass (C-10) composite. The implications of these results on cryocooler design are discussed
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