4,090 research outputs found

    Algae from the inland ice of Greenland. [Translation from: Kongl.Vetenskaps-Akademiens Forhandlingar 1871(2) 293-296, 1871.]

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    On the large inland ice cover of Greenland, where the temperature even during the short summer, falls below freezing some time during the daily 24 hours, it is still possible to find organic life. The author found in melted ice water several species of algae on his ”walk” in the latter part of July 1870. The article describes the finds and tries to identify the algae to family level

    Transient reflectance of photoexcited Cd\u3csub\u3e3\u3c/sub\u3eAs\u3csub\u3e2\u3c/sub\u3e

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    We report ultrafast transient-grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd3As2, at both room temperature and 80 K. After photoexcitation with 1.5-eV photons, charge-carriers relax by two processes, one of duration 500 fs and the other of duration 3.1 ps. By measuring the complex phase of the change in reflectance, we determine that the faster signal corresponds to a decrease in absorption, and the slower signal to a decrease in the light\u27s phase velocity, at the probe energy. We attribute these signals to electrons\u27 filling of phase space, first near the photon energy and later at lower energy. We attribute their decay to cooling by rapid emission of optical phonons, then slower emission of acoustic phonons. We also present evidence that both the electrons and the lattice are strongly heated

    Mach-Zehnder Interferometry in a Strongly Driven Superconducting Qubit

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    We demonstrate Mach-Zehnder-type interferometry in a superconducting flux qubit. The qubit is a tunable artificial atom, whose ground and excited states exhibit an avoided crossing. Strongly driving the qubit with harmonic excitation sweeps it through the avoided crossing two times per period. As the induced Landau-Zener transitions act as coherent beamsplitters, the accumulated phase between transitions, which varies with microwave amplitude, results in quantum interference fringes for n=1...20 photon transitions. The generalization of optical Mach-Zehnder interferometry, performed in qubit phase space, provides an alternative means to manipulate and characterize the qubit in the strongly-driven regime.Comment: 14 pages, 6 figure

    The Cedell method (cerclage wire and staple) leads to less reoperations than the AO method.

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    Background and purpose - Fractures of the lateral malleolus often require open reduction and internal fixation (ORIF). Despite uneventful fracture healing, many patients will suffer from long-term detriments after ORIF, such as local tenderness that requires hardware removal. In Sweden, there are 2 major fixation methods, either the AO method (plate and screws) or the Cedell method (cerclage wire and staple). The purpose of this study was to establish whether there is a difference in extraction frequency between the 2 methods. Patients and methods - We performed a retrospective comparative study of all isolated fractures through the lateral malleolus that were operated at SkĂĄne University Hospital, Sweden, during the period January 2007 to December 2010. 347 patients fulfilled the inclusion criteria (dislocated Weber B isolated fractures of the lateral malleolus) and were categorized according to fixation method. The numbers of reoperations, with preceding indication, were established from the charts. The median follow-up time was 59 (38-86) months after the primary surgery. Results - 22% of the 110 patients treated with the AO method underwent a reoperation, as compared to 8% of the 237 patients treated with the Cedell method (p < 0.001). The median time to extraction was 16 (4-55) months. Interpretation - Less implant removal is needed with the Cedell method than with the conventional AO method. This favors the use of the Cedell method in uncomplicated Weber B lateral ankle fractures, provided that other clinical parameters are comparable

    How much larger quantum correlations are than classical ones

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    Considering as distance between two two-party correlations the minimum number of half local results one party must toggle in order to turn one correlation into the other, we show that the volume of the set of physically obtainable correlations in the Einstein-Podolsky-Rosen-Bell scenario is (3 pi/8)^2 = 1.388 larger than the volume of the set of correlations obtainable in local deterministic or probabilistic hidden-variable theories, but is only 3 pi^2/32 = 0.925 of the volume allowed by arbitrary causal (i.e., no-signaling) theories.Comment: REVTeX4, 6 page

    Distribution of nearest distances between nodal points for the Berry function in two dimensions

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    According to Berry a wave-chaotic state may be viewed as a superposition of monochromatic plane waves with random phases and amplitudes. Here we consider the distribution of nodal points associated with this state. Using the property that both the real and imaginary parts of the wave function are random Gaussian fields we analyze the correlation function and densities of the nodal points. Using two approaches (the Poisson and Bernoulli) we derive the distribution of nearest neighbor separations. Furthermore the distribution functions for nodal points with specific chirality are found. Comparison is made with results from from numerical calculations for the Berry wave function.Comment: 11 pages, 7 figure

    Non-Simplified SUSY: Stau-Coannihilation at LHC and ILC

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    If new phenomena beyond the Standard Model will be discovered at the LHC, the properties of the new particles could be determined with data from the High-Luminosity LHC and from a future linear collider like the ILC. We discuss the possible interplay between measurements at the two accelerators in a concrete example, namely a full SUSY model which features a small stau_1-LSP mass difference. Various channels have been studied using the Snowmass 2013 combined LHC detector implementation in the Delphes simulation package, as well as simulations of the ILD detector concept from the Technical Design Report. We investigate both the LHC and ILC capabilities for discovery, separation and identification of various parts of the spectrum. While some parts would be discovered at the LHC, there is substantial room for further discoveries at the ILC. We finally highlight examples where the precise knowledge about the lower part of the mass spectrum which could be acquired at the ILC would enable a more in-depth analysis of the LHC data with respect to the heavier states.Comment: 42 pages, 18 figures, 12 table
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