There exists considerable interest in dark matter candidates that can reduce cosmological structure at sub-galactic scales through a suppression of the power spectrum of primordial perturbations as well as have a primordial velocity distribution to produce cores in the smallest-scale dwarf halos. Light keV-mass-scale sterile neutrinos can be such a “warm” dark matter candidate and are still via...

in this paper we study the structure and the commutativity of a ring r, in which for each x,y ? r, there exist two integers depending on x,y such that [x,y]k equals x n or y n.

Neutrino oscillations in a core-collapse supernova may be responsible for the observed rapid motions of pulsars. Given the present bounds on the neutrino masses, the pulsar kicks require a sterile neutrino with mass 2–20 keV and a small mixing with the active neutrinos. The same particle can be the cosmological dark matter. Its existence can be confirmed the by the X-ray telescopes if they dete...

Recent Chandra and Newton observations indicate that there are two-temperature components (T ∼ 8 keV, 0.8 keV) of the diffuse x-rays emitted from deep inside the center of Milky Way. We show that this can be explained by the existence of sterile neutrinos, which decay to emit photons that can be bound-free absorbed by the isothermal hot gas particles in the center of Milky Way. This model can a...

In a retrospective study of 15 patients who were treated with collapse therapy for pulmonary tuberculosis on an average 30 years previously, we found 16 instances of exudation in the residual pocket: four were sterile and without fistula, ten had bronchial fistulae, one had an esophageal fistula, and one was a tuberculous empyema without fistula. Among the 11 exudations with bronchial or esopha...

Abstract: Kurie-plot experiments allow for neutrino-mass measurements based on kinematics in an almost model-independent manner. A future tritium-based KATRIN-like experiment can be sensitive to light sterile neutrinos with masses below 18 keV, which are among the prime candidates for warm dark matter. Here we consider such keV neutrinos in left-right symmetric extensions, i.e. coupled to right...

Context. The sterile neutrino is an excellent dark matter candidate, which can be searched for in a wide range of astrophysical sites. It has previously been shown that the optimal search strategy is to consider dwarf galaxies belonging to the Milky Way. Aims. We search for line emission from decaying dark matter. Methods. We analyse publicly available Chandra X-ray observations of the dwarf ga...

The purpose of the present study was to investigate possible methods to enhance the rate of biodegradation of oil sludge from crude oil tank bottom, thus reducing the time usually required for bioremediation. Enhancement of biodegradation was achieved through bioaugmentation and biostimulation. About 10% and 20% sludge contaminated sterile and non-sterile soil samples were treated with bacteria...