the geometry of a collector is one of the important factors that can increase the incident radiation on the collector surface. in the present study, the incident radiation for a stationary collector with cone geometry, i.e. a conical collector, is theoretically and experimentally investigated. this type of collector is always stable and does not need a fixture to install. moreover, it has a sym...

We consider the issue of hemispherical power asymmetry in the three-year WMAP data, adopting a previously introduced modulation framework. Computing both frequentist probabilities and Bayesian evidences, we find that the model consisiting of an isotropic CMB sky modulated by a dipole field, gives a substantially better fit to the observations than the purely isotropic model, even when accountin...

The microwave sky shows unexpected features at the largest angular scales, among them the alignments of the dipole, quadrupole and octopole. Motivated by recent X-ray cluster studies, we investigate the possibility that local structures at the 100 hMpc scale could be responsible for such correlations. These structures give rise to a local Rees–Sciama contribution to the microwave sky that may a...

A decrease in stratospheric ozone may result in a serious threat to plants, since biologically active short-wavelength ultraviolet-B (UV-B 280–320 nm) radiation will increase even with a relatively small decrease in ozone. Numerous investigations have demonstrated that the effect of UV-B enhancements on plants includes reduction in grain yield, alteration in species competition, susceptibility ...

We study the angular power spectrum estimate in order to search for large scale anisotropies in the arrival directions distribution of the highest-energy cosmic rays. We show that this estimate can be performed even in the case of partial sky coverage and validated over the full sky under the assumption that the observed fluctuations are statistically spatial stationary. If this hypothesis whic...

The paucity of reliable achromatic breaks in Gamma-Ray Burst afterglow light curves motivates independent measurements of the jet aperture. Orphan afterglow (OA) searches, especially at radio wavelengths, have long been the classic alternative. So far, no candidate has been confirmed. These survey data have been interpreted assuming a uniformly emitting jet with sharp edges (“top-hat” jet), in ...

The paucity of reliable achromatic breaks in Gamma-Ray Burst afterglow light curves motivates independent measurements of the jet aperture. Orphan afterglow (OA) searches, especially at radio wavelengths, have long been the classic alternative. These survey data have been interpreted assuming a uniformly emitting jet with sharp edges (“top-hat” jet), in which case the ratio of nearly isotropic ...

The change of signature of a metric is explained using simple examples and methods. The Klein-Gordon field on a signature-changing background is discussed, and it is shown how the approach of Dray et al. can be corrected to ensure that the KleinGordon equation holds. Isotropic cosmologies are discussed, and it is shown how the approach of Ellis et al. can be corrected to ensure that the Einstei...

Your thesaurus codes are: missing; you have not inserted them Abstract. We report here the first full sky component separation and CMB power spectrum estimation using a Wiener filtering technique on simulated data from the up-coming MAP experiment, set to launch in early 2001. The simulations included contributions from the three dominant astrophysical components expected in the five MAP spectr...

The whole sky differential star counts (DSC) with 1 degree resolution are retrieved from 2MASS online data service. Galaxy with double exponential thin and thick disks and a single power law luminosity function (LF) is used to interpret the 2MASS data. The slope of the DSC appears roughly isotropic over the whole sky, the average value is ∼ 0.32, which corresponds to a power law index ∼ 1.8 of ...