133 research outputs found
Strongly focused light beams interacting with single atoms in free space
We construct 3-D solutions of Maxwell's equations that describe Gaussian
light beams focused by a strong lens. We investigate the interaction of such
beams with single atoms in free space and the interplay between angular and
quantum properties of the scattered radiation. We compare the exact results
with those obtained with paraxial light beams and from a standard input-output
formalism. We put our results in the context of quantum information processing
with single atoms.Comment: 9 pages, 9 figure
No cosmological domain wall problem for weakly coupled fields
After inflation occurs, a weakly coupled scalar field will in general not be
in thermal equilibrium but have a distribution of values determined by the
inflationary Hubble parameter. If such a field subsequently undergoes discrete
symmetry breaking, then the different degenerate vacua may not be equally
populated so the domain walls which form will be `biased' and the wall network
will subsequently collapse. Thus the cosmological domain wall problem may be
solved for sufficiently weakly coupled fields in a post-inflationary universe.
We quantify the criteria for determining whether this does happen, using a
Higgs-like potential with a spontaneously broken symmetry.Comment: 17 pages, 4 figures (Revtex), clarifying Comments added in
Introduction; to appear in Phys. Rev
Nurture, nature and some very dubious social skills: An interpretative phenomenological analysis of talent identification practices in elite English youth soccer
This paper reports qualitative findings regarding the concepts and practices utilised in talent identification (TI) among professional coaches working in English youth soccer. Using interpretative phenomenological analysis, detailed interviews with seven such coaches are explored, with a view to elucidating the links between understanding, practice, experience and professional context. Findings reveal three superordinate themes, relating to (1) a primarily ‘nurtured’ and trainable understanding of the broad concept of talent itself, (2) an ostensibly contradictory model of semi-static player psychology, and (3) a highly selective mechanism for separating evidence for ‘mental strength’ and ‘social skills’. It is contended that these findings underscore a case for more thorough interrogation of the real worlds inhabited by coaches, such that ideas about ‘good practice’ in TI might be more effectively reconciled with grounded knowledge of the practical everyday necessities of being a coach
Effect of vitamin K on bone integrity and eggshell quality of white hen at the final phase of the laying cycle
New insights into the genetic etiology of Alzheimer's disease and related dementias
Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele
Crescimento, desenvolvimento e retardamento da senescência foliar em girassol de vaso (Helianthus annuus L.): fontes e doses de nitrogênio
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