10,291 research outputs found

    Distribution of the Water Scorpion \u3ci\u3eNepa Apiculata\u3c/i\u3e (Hemiptera: Nepidae) in Wisconsin

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    The water scorpion Nepa apiculata Uhler was considered rare in Wiscon- sin by Hilsenhoff (1984), who collected only 11 individuals during a 25-year period. All of his collections were from overwintering sites, especially debris in streams, during early spring or autumn (Hilsenhoff, pers. comm.). He concluded that the species was restricted to southern Wisconsin. Recent collections indicate that N. apiculata is more widely distributed. These records, summarized below, are documented with specimens in the University of Wisconsin-Madison insect collection

    Scheduling language and algorithm development study. Volume 2, phase 2: Introduction to plans programming

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    A user guide for the Programming Language for Allocation and Network Scheduling (PLANS) is presented. Information is included for the construction of PLANS programs. The basic philosophy of PLANS is discussed, and access and update reference techniques are described along with the use of tree structures

    Initial investigations into the damping characteristics of wire rope vibration isolators

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    Passive dampers composed of coils of multi-strand wire rope are investigated. Analytical results range from those produced by complex NASTRAN models to those of a Coulomb damping model with variable friction force. The latter agrees well with experiment. The Coulomb model is also utilized to generate hysteresis loops. Various other models related to early experimental investigations are described. Significant closed-form static solutions for physical properties of single-and multi-strand wire ropes are developed for certain specific geometries and loading conditions. NASTRAN models concentrate on model generation and mode shapes of 2-strand and 7-strand straight wire ropes with interfacial forces

    Lead Precipitation Fluxes at Tropical Oceanic Sites Determined From ^(210)Pb Measurements

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    Concentrations of lead, ^(210)Pb, and ^(210)Po were measured in rain selected for least influence by local sources of contamination at several tropical and subtropical islands (Enewetak; Pigeon Key, Florida; and American Samoa) and shipboard stations (near Bermuda and Tahiti). Ratios expressed as ng Pb/dpm ^(210)Pb in rain were 250–900 for Pigeon Key (assuming 12% adsorption for ^(210)Pb and no adsorption for lead), depending on whether the air masses containing the analyzed rain came from the Caribbean or from the continent, respectively; about 390 for the northern Sargasso Sea downwind from emissions of industrial lead in North America; 65 for Enewetak, remote from continental emissions of industrial lead in the northern hemisphere; and 14 near Tahiti, a remote location in the southern hemisphere where industrial lead emissions to the atmosphere are much less than in the northern hemisphere. (The American Samoa sample yielded a higher ratio than Tahiti; the reason for this is not clear but may be due to local Pb sources.) The corresponding fluxes of lead to the oceans, based on measured or modeled ^(210)Pb precipitation fluxes, are about 4 ng Pb/cm^2y for Tahiti, 10 for Enewetak, and 270 for the Sargasso Sea site, and between 110 to 390 at Pigeon Key

    Anomalous phonon behavior in the high temperature shape memory alloy: TiPd:Cr

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    Ti50 Pd50-xCrx is a high temperature shape memory alloy with a martensitic transformation temperature strongly dependent on the Cr composition. Prior to the transformation a premartensitic phase is present with an incommensurate modulated cubic lattice with wave vector of q0=(0.22, 0.22, 0). The temperature dependence of the diffuse scattering in the cubic phase is measured as a function temperature for x=6.5, 8.5, and 10 at. %. The lattice dynamics has been studied and reveals anomalous temperature and q-dependence of the [110]-TA2 transverse phonon branch. The phonon linewidth is broad over the entire Brillouin zone and increases with decreasing temperature, contrary to the behavior expected for anharmonicity. No anomaly is observed at q0. The results are compared with first principles calculation of the phonon structure.Comment: 26 pages, 11 figure

    Scheduling language and algorithm development study. Volume 3, phase 2: As-built specifications for the prototype language and module library

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    Detailed specifications of the prototype language and module library are presented. The user guide to the translator writing system is included

    A white-light trap for Bose-Einstein condensates

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    We propose a novel method for trapping Bose-condensed atoms using a white-light interference fringe. Confinement frequencies of tens of kHz can be achieved in conjunction with trap depths of only a few micro-K. We estimate that lifetimes on the order of 10 s can be achieved for small numbers of atoms. The tight confinement and shallow depth permit tunneling processes to be used for studying interaction effects and for applications in quantum information.Comment: 10 pages with 3 figure

    Long-lived, long-period radial velocity variations in Aldebaran: A planetary companion and stellar activity

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    We investigate the nature of the long-period radial velocity variations in Alpha Tau first reported over 20 years ago. We analyzed precise stellar radial velocity measurements for Alpha Tau spanning over 30 years. An examination of the Halpha and Ca II 8662 spectral lines, and Hipparcos photometry was also done to help discern the nature of the long-period radial velocity variations. Our radial velocity data show that the long-period, low amplitude radial velocity variations are long-lived and coherent. Furthermore, Halpha equivalent width measurements and Hipparcos photometry show no significant variations with this period. Another investigation of this star established that there was no variability in the spectral line shapes with the radial velocity period. An orbital solution results in a period of P = 628.96 +/- 0.90 d, eccentricity, e = 0.10 +/- 0.05, and a radial velocity amplitude, K = 142.1 +/- 7.2 m/s. Evolutionary tracks yield a stellar mass of 1.13 +/- 0.11 M_sun, which corresponds to a minimum companion mass of 6.47 +/- 0.53 M_Jup with an orbital semi-major axis of a = 1.46 +/- 0.27 AU. After removing the orbital motion of the companion, an additional period of ~ 520 d is found in the radial velocity data, but only in some time spans. A similar period is found in the variations in the equivalent width of Halpha and Ca II. Variations at one-third of this period are also found in the spectral line bisector measurements. The 520 d period is interpreted as the rotation modulation by stellar surface structure. Its presence, however, may not be long-lived, and it only appears in epochs of the radial velocity data separated by ∼\sim 10 years. This might be due to an activity cycle. The data presented here provide further evidence of a planetary companion to Alpha Tau, as well as activity-related radial velocity variations.Comment: 18 pages, 14 figures. Accepted for publication in Astronomy and Astrophysic

    Statistical analysis on testing of an entangled state based on Poisson distribution framework

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    A hypothesis testing scheme for entanglement has been formulated based on the Poisson distribution framework instead of the POVM framework. Three designs were proposed to test the entangled states in this framework. The designs were evaluated in terms of the asymptotic variance. It has been shown that the optimal time allocation between the coincidence and anti-coincidence measurement bases improves the conventional testing method. The test can be further improved by optimizing the time allocation between the anti-coincidence bases.Comment: This paper is an extended version of the theoretical part of v1 of quant-ph/0603254.quant-ph/0603254 is revised so that it is more familiar to experimentalist
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