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[en] The objective of this paper is to explain the role and application of alarm communication link supervision in security systems such as for nuclear facilities. The vulnerabilities of the various types of alarm communication links will be presented. Throughout the paper, an effort has been made to describe only those technologies commercially available and to avoid speculative theoretical solutions
[en] In order to give the standard scenario of the astrophysics, it is studied the Einstein theory with minimally coupled scalar field and the cosmological term by considering the scalar field as a candidate of the dark matter. It is obtained the exact solution in the cosmological scale and the approximate gravitational potential in the galactic or solar scale. It is found that the scalar field plays the role of the dark matter in some sense in the cosmological scale but it does not play the role of the dark matter in the galactic or solar scale within the approximation
[en] The observations by Collins et al. (1986) and Burstein et al. (1986) that suggest that the Hubble expansion on scales of about 50/h Mpc is distorted by matter currents of large amplitude are discussed, and implications are compared with model predictions. It is emphasized that the cold dark matter dipole anisotropy can provide an independent measure of peculiar velocity relative to the comoving frame. Theoretical results obtained from analysis of the IRAS Point Source Catalogue (which which provides a uniformly selected galaxy sample with nearly full sky coverage) are discussed. It is noted that the density parameter Omega sub 0 cannot be measured using the IRAS sample unless such an independent measure of the peculiar velocity of the sample itself is obtained. 12 references
[en] We argue that the recent observations of large scale bulk flows by Kashlinsky et al. has a natural explanation in terms of superhorizon inhomogeneities induced by nonlocal entanglement of our Hubble volume with modes and domains beyond the horizon. This entanglement gives rise to corrections to the Newtonian potential on a characteristic scale L1 ≅ 103H−1, and it induces a dipole and quadrupole contribution in the CMB. We also show that these induced multipoles are aligned with each other, with the alignment axis normal to their plane being oriented along the preferred frame determined by the dipole. We also give other potential tests of our hypothesis
[en] We establish a correspondence between interacting agegraphic dark energy model and the quintessence scalar field in a non-flat universe. We demonstrate that the agegraphic evolution of the universe can be described completely by a single quintessence scalar field. We also reconstruct the potential of the interacting agegraphic quintessence dark energy as well as the dynamics of the quintessence scalar field which describe the quintessence cosmology
[en] Warped disks are almost ubiquitous among spiral galaxies. Here we revisit and test the 'flyby scenario' of warp formation, in which impulsive encounters between galaxies are responsible for warped disks. Based on N-body simulations, we investigate the morphological and kinematical evolution of the stellar component of disks when galaxies undergo flyby interactions with adjacent dark matter halos. We find that the so-called 'S'-shaped warps can be excited by flybys and sustained for even up to a few billion years, and that this scenario provides a cohesive explanation for several key observations. We show that disk warp properties are governed primarily by the following three parameters: (1) the impact parameter, i.e., the minimum distance between two halos; (2) the mass ratio between two halos; and (3) the incident angle of the flyby perturber. The warp angle is tied up with all three parameters, yet the warp lifetime is particularly sensitive to the incident angle of the perturber. Interestingly, the modeled S-shaped warps are often non-symmetric depending on the incident angle. We speculate that the puzzling U- and L-shaped warps are geometrically superimposed S-types produced by successive flybys with different incident angles, including multiple interactions with a satellite on a highly elongated orbit.
[en] Formation of black holes may be constrained by intrinsic parameters characterizing them such as electric charge. Here we discuss the effects of a relatively minute excess of charge on extremal black hole formation and the horizon. We extend the implications of this argument to the formation of primordial black holes (PBH) in the early universe which gives a possible reason for the lack of detection of Hawking radiation. These charge limits also apply to dark matter (DM) particles that may form PHBs in the early universe. The constraint thus obtained on the electric charge of DM particles could also account for the required magnitude of the repulsive dark energy (DE) currently causing an accelerated universe which provides a possible unified picture of DM and DE.