228 research outputs found

    Gravitational wave background from coalescing compact stars in eccentric orbits

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    Stochastic gravitational wave background produced by a stationary coalescing population of binary neutron stars in the Galaxy is calculated. This background is found to constitute a confusion limit within the LISA frequency band up to a limiting frequency \NUlim{}\sim 10^{-3} Hz, leaving the frequency window ∼10−3\sim 10^{-3}--10−210^{-2} Hz open for the potential detection of cosmological stochastic gravitational waves and of signals involving massive black holes out to cosmological distances.Comment: 6 pages, 7 figure

    Size-dependent Surface States on Strained Cobalt Nanoislands on Cu(111)

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    Low-temperature scanning tunneling spectroscopy over Co nanoislands on Cu(111) showed that the surface states of the islands vary with their size. Occupied states exhibit a sizeable downward energy shift as the island size decreases. The position of the occupied states also significantly changes across the islands. Atomic-scale simulations and ab inito calculations demonstrate that the driving force for the observed shift is related to size-dependent mesoscopic relaxations in the nanoislands.Comment: 4 pages, 4 figure

    Spectator Effects in the Decay B -> K \gamma \gamma

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    We report the results of the first computation related to the study of the spectator effects in the rare decay mode B→KγγB\to K \gamma \gamma within the framework of Standard Model. It is found that the account of these effects results in the enhancement factor for the short-distance reducible contribution to the branching ratio.Comment: 5 pages, 5 figures, RevTeX

    Broad-band gravitational-wave pulses from binary neutron stars in eccentric orbits

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    Maximum gravitational wave emission from binary stars in eccentric orbits occurs near the periastron passage. We show that for a stationary distribution of binary neutron stars in the Galaxy, several high-eccentricity systems with orbital periods in the range from tens of minutes to several days should exist that emit broad gravitational-wave pulses in the frequency range 1-100 mHz. The space interferometer LISA could register the pulsed signal from these system at a signal-to-noise ratio level S/N>55S/N>5\sqrt{5} in the frequency range ∼10−3−10−1\sim 10^{-3}-10^{-1} Hz during one-year observational time. Some detection algorithms for such a signal are discussed.Comment: 17 pages, LATEX, 3 figures, Astronomy Letters, 2002, in press; typos corrected, refference adde

    Neutral Particles in Light of the Majorana-Ahluwalia Ideas

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    The first part of this article (Sections I and II) presents oneself an overview of theory and phenomenology of truly neutral particles based on the papers of Majorana, Racah, Furry, McLennan and Case. The recent development of the construct, undertaken by Ahluwalia [{\it Mod. Phys. Lett. A}{\bf 9} (1994) 439; {\it Acta Phys. Polon. B}{\bf 25} (1994) 1267; Preprints LANL LA-UR-94-1252, LA-UR-94-3118], could be relevant for explanation of the present experimental situation in neutrino physics and astrophysics. In Section III the new fundamental wave equations for self/anti-self conjugate type-II spinors, proposed by Ahluwalia, are re-casted to covariant form. The connection with the Foldy-Nigam-Bargmann-Wightman- Wigner (FNBWW) type quantum field theory is found. The possible applications to the problem of neutrino oscillations are discussed.Comment: REVTEX file. 21pp. No figure

    INFLUENCE OF TECHNOLOGICAL STRESS ON NON-SPECIFIC RESISTANCE OF THE ORGANISM OF COWS

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    Background. The intensification of animal husbandry leads to a violation of the adaptive capabilities of the body, a decrease in productivity and natural resistance of animals. The study of nonspecific factors of protection of the cow's body will allow us to develop ways to increase the immune status and as additional information can be used in breeding work for the selection of highly resistant parent pairs. Purpose. The study of the cellular and humoral link of nonspecific resistance in the development of a stress reaction in cattle after the action of technological stress on the body of cows. Materials and methods. The work was carried out on 20 clinically healthy highly productive black-and-white cows. The stressor for the cows was the regrouping, the change of attendants, the conduct of veterinary and sanitary manipulations. The total number of leukocytes, leukogram, bactericidal and lysozyme activity of the blood serum of cows were studied by standard clinical and laboratory methods and the morphology of leukocytes on a scanning electron microscope before and 3, 14, 30 days after technological stress. Results. On days 3-14 after stress, leukocytosis, neutrophilia, monocytosis and lymphopenia were detected relative to the initial level. When using high-resolution microscopy using a scanning electron microscope, the appearance of NEToses in the blood of cows after technological stress was detected. A decrease in the bactericidal activity of serum on the 3rd day after stress with its subsequent increase was established, on the contrary, an increase in lysozyme on the 3rd day was accompanied by its subsequent decrease by 30 days after the technological stress relative to the initial level. Conclusion. The data obtained indicate that the body's defenses are a dynamic physiological indicator, which must be considered as a general resistance of the cattle body to stressors in order to prevent the disruption of the body's adaptive capabilities

    A rapid synthesis of nanofibrillar cellulose/polystyrene composite via ultrasonic treatment

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    A new method of the synthesis of nanofibrillar cellulose/polystyrene composite based on ultrasonic treatment of styrene emulsion in cellulose-water solution was elaborated. A new approach does not require additional heating and proposes a significantly faster synthesis (15 min, 45 °C) of the target composite compared to the methods described previously. A comprehensive analysis did not reveal any significant differences between mechanical, physical and biodegradable properties of the composite obtained by ultrasonic method and that one obtained by conventional thermal method, which requires much higher temperature (above 75 °C) and reaction duration (from 3 h)
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