14,222 research outputs found

    Individual recognition between mother and infant bats (Myotis)

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    The recognition process and the basis for that recognition, in brown bats, between mother and infant are analyzed. Two parameters, ultrasonic communication and olfactory stimuli, are investigated. The test animals were not allowed any visual contact. It was concluded that individual recognition between mother and infant occurred. However, it could not be determined if the recognition was based on ultrasonic signals or olfactory stimuli

    Static inverters which sum a plurality of waves Patent

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    Describing static inverter with single or multiple phase outpu

    Improved Astrometry and Photometry for the Luyten Catalog. II. Faint Stars and the Revised Catalog

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    We complete construction of a catalog containing improved astrometry and new optical/infrared photometry for the vast majority of NLTT stars lying in the overlap of regions covered by POSS I and by the second incremental 2MASS release, approximately 44% of the sky. The epoch 2000 positions are typically accurate to 130 mas, the proper motions to 5.5 mas/yr, and the V-J colors to 0.25 mag. Relative proper motions of binary components are measured to 3 mas/yr. The false identification rate is ~1% for 11 < V < 18 and substantially less at brighter magnitudes. These improvements permit the construction of a reduced proper motion diagram that, for the first time, allows one to classify NLTT stars into main-sequence (MS) stars, subdwarfs (SDs), and white dwarfs (WDs). We in turn use this diagram to analyze the properties of both our catalog and the NLTT catalog on which it is based. In sharp contrast to popular belief, we find that NLTT incompleteness in the plane is almost completely concentrated in MS stars, and that SDs and WDs are detected almost uniformly over the sky DEC > -33 deg. Our catalog will therefore provide a powerful tool to probe these populations statistically, as well as to reliably identify individual SDs and WDs.Comment: 16 figures. We will make the revised NLTT publicly available on acceptance of the paper, or no later than July 18, 200

    Classifying Luyten Stars Using An Optical-Infrared Reduced Proper Motion Diagram

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    We present a V-J reduced proper motion (RPM) diagram for stars in the New Luyten Two-Tenths (NLTT) catalog. In sharp contrast to the RPM diagram based on the original NLTT data, this optical-infrared RPM diagram shows distinct tracks for white dwarfs, subdwarfs, and main-sequence stars. It thereby permits the identification of white-dwarf and subdwarf candidates that have a high probability of being genuine.Comment: Accepted ApJL version. 3 figures (2 in color). Table of candidate new WDs closer than 20 pc is now include

    Integrable Electron Model with Correlated Hopping and Quantum Supersymmetry

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    We give the quantum analogue of a recently introduced electron model which generalizes the Hubbard model with additional correlated hopping terms and electron pair hopping. The model contains two independent parameters and is invariant with respect to the quantum superalgebra Uq(gl(21))U_q(gl(2|1)). It is integrable in one dimension by means of the quantum inverse scattering method.Comment: 7 pages, AmsTex fil

    Photoassociation to the 2(1)Sigma(g)(+) state in ultracold 85Rb2 in the presence of a shape resonance

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    We report the first observation of photoassociation to the 2(1)Sigma(g)(+) state of 85Rb2 . We have observed two vibrational levels (v'=98, 99) below the 5s1/2+5p1/2 atomic limit and eleven vibrational levels (v'=102-112) above it. The photoassociation---and subsequent spontaneous emission---occur predominantly between 15 and 20 Bohr in a region of internuclear distance best described as a transition between Hund's case (a) and Hund's case (c) coupling. The presence of a g-wave shape resonance in the collision of two ground-state atoms affects the photoassociation rate and lineshape of the J'= 3 and 5 rotational levels.Comment: to appear in PR

    Complementary algorithms for graphs and percolation

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    A pair of complementary algorithms are presented. One of the pair is a fast method for connecting graphs with an edge. The other is a fast method for removing edges from a graph. Both algorithms employ the same tree based graph representation and so, in concert, can arbitrarily modify any graph. Since the clusters of a percolation model may be described as simple connected graphs, an efficient Monte Carlo scheme can be constructed that uses the algorithms to sweep the occupation probability back and forth between two turning points. This approach concentrates computational sampling time within a region of interest. A high precision value of pc = 0.59274603(9) was thus obtained, by Mersenne twister, for the two dimensional square site percolation threshold.Comment: 5 pages, 3 figures, poster version presented at statphys23 (2007

    Thermally excited Trivelpiece–Gould modes as a pure electron plasma temperature diagnostic

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    Thermally excited plasma modes are observed in trapped, near-thermal-equilibrium pure electron plasmas over a temperature range of 0.05<kT<5 eV. The modes are excited and damped by thermal fluctuations in both the plasma and the receiver electronics. The thermal emission spectra together with a plasma-antenna coupling coefficient calibration uniquely determine the plasma (and load) temperature. This calibration is obtained from the mode spectra themselves when the receiver-generated noise absorption is measurable; or from separate wave reflection/absorption measurements; or from kinetic theory. This nondestructive temperature diagnostic agrees well with standard diagnostics, and may be useful for expensive species such as antimatter
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