31,347 research outputs found
Probing the largest scale structure in the universe with polarization map of galaxy clusters
We introduce a new formalism to describe the polarization signal of galaxy
clusters on the whole sky. We show that a sparsely sampled, half-sky map of the
cluster polarization signal at would allow to better characterize the
very large scale density fluctuations. While the horizon length is smaller in
the past, two other competing effects significantly remove the contribution of
the small scale fluctuations from the quadrupole polarization pattern at . For the standard Lambda-CDM universe with vanishing tensor mode, the
quadrupole moment of the temperature anisotropy probed by WMAP is expected to
have a ~32% contribution from fluctuations on scales below 6.3h^{-1}Gpc. This
percentage would be reduced to ~2% level for the quadrupole moment of
polarization pattern at . A cluster polarization map at
would shed light on the potentially anomalous features of the largest scale
structure in the observable universe.Comment: 5 pages, 2 figures, revised version, to appear in PR
Variation of seed characteristic from natural and artificial selection in the genus Papaver
Papaveraceae is a mediterranean plant family with an important scientific, commercial and ethnobotanical interest. Includes wild species, which are distributed throughout the Spanish territory, as Papaver rhoeas, P. dubium, P. bracteatum, P. hybridum and the wild type of P. somniferum, which are representatives of the natural selection. The species with the greatest commercial interest is P. somniferum, whose management through improvement lines reflects the most profitable plant characteristics obtained by artificial selection: fast and vigorous growth, multiple flowers and big size capsules (1), traits that increase the production of morphine, codeine and thebaine among others opiates derived from the capsule leachate. Occasionally, some breeding lines of P. somniferum shown wild features, such as capsule dehiscence or extended germination time. Papaver becomes, thereby, an interesting plant genus to analyze the differential evolution experienced through natural and artificial selection. In this regard, previous studies reported that seed surface patter can be used in taxonomic classification of Papaveraceae family members (2). The main goal of this project was to characterize several seed traits variation among wild and cultivated samples. Seed size and shape was characterized using images analysis from macro-photography and the software ImageJ. Seed color, defined in the L, a*, b* color space, was recorded with an automatic colorimeter. Electron scanning microscopy (SEM) micrographs were used to study seed surface crosslinked patterns. Finally, confocal scanning microscopy allowed a preliminary approach to the internal seed tissue structure. The results shown that wild species seeds have deeper color than P. somniferum breeding lines but even among those it is possible to distinguish at least four main differentiated groups by color. Likewise, even if all breeded P. somniferum samples had larger seeds than wild species, probably as the results of artificial selection, there were clear variation among them. We discuss if the variations in these seed characteristics was the unintended result of the artificial trait breeding selection with agronomic interest.
References
* (1) Referencia general aquÃ
* (2) Referencia sobre caracteres de la superficie de la semilla como indicadores taxonómicos
Funding
Authors thanks funding support from Alcaliber S.A. (OTRI-UMA-8.06/5.03.4280) and the University of Málaga to EMC, and Spanish Ministry of Enconomy and EU grant for AJMA (RYC-2011-08839).Universidad de Málaga. Campus de Excelencia Internacional AndalucÃa Tech
Correlator expansion approach to stationary states of weakly coupled cavity arrays
We introduce a method for calculating the stationary state of a translation
invariant array of weakly coupled cavities in the presence of dissipation and
coherent as well as incoherent drives. Instead of computing the full density
matrix our method directly calculates the correlation functions which are
relevant for obtaining all local quantities of interest. It considers an
expansion of the correlation functions and their equations of motion in powers
of the photon tunneling rate between adjacent cavities, leading to an exact
second order solution for any number of cavities. Our method provides a
controllable approximation for weak tunneling rates applicable to the strongly
correlated regime that is dominated by nonlinearities in the cavities and thus
of high interest.Comment: contribution to J. Phys. B special issue celebrating Jaynes-Cummings
physic
Casino Atmospherics from a Customer\u27s Perspective: A Re-Examination
Considerable research in recent years has examined the influence of physical evidence, or atmosphere, in a variety of service settings, including leisure services. Not fully covered has been the area of atmosphere in a casino gaming setting. This extension of a previous study further investigates atmospherics in casinos. The findings showed that customers defined casino atmosphere in five key elements: theme, floor layout, ceiling height, employee uniforms, and noise level. Three of the five contributed positively to a player\u27s satisfaction with the gaming experience as shown by the regression analysis. This reinforces previous indications of the need for casino management to create an inviting atmosphere that will maximize customer satisfaction, with specific attention to those aspects that players appear to value most highly
- …