779 research outputs found

    Introducing the READ Scale: Qualitative Statistics for Academic Reference Services

    Get PDF
    The article describes the concept, methodology, data gathering and study expansion using the Reference Effort Assessment Data (READ) scale developed at Carnegie Mellon University in Pittsburgh, Pennsylvania. READ Scale pertains to a tool for recording vital supplemental qualitative statistics gathered when reference librarians assist users with their inquiries or research-related activities. The scale is easy to use compared with the traditional method of gathering reference statistics

    Testing The Viability Of The READ Scale (Reference Effort Assessment Data)®: Qualitative Statistics For Academic Reference Services

    Get PDF
    The READ Scale (Reference Effort Assessment Data) is a six-point scale tool for recording qualitative statistics by placing an emphasis on recording effort, knowledge, skills, and teaching used by staff during a reference transaction. Institutional research grants enabled the authors to conduct a national study of the READ Scale at 14 diverse academic libraries in spring of 2007 and test its viability as a tool for recording reference statistics. The study data were collected from 170 individuals and 24 service points with over 22,000 transactions analyzed. There was a 52 percent return rate of an online survey of participants, with more than 80 percent of respondents indicating they would recommend or adopt the Scale for recording reference transactions. The authors suggest that the READ Scale has the potential to transform how reference statistics are gathered, interpreted, and valued. This paper presents the findings of a nationwide study testing the Scale in spring 2007 and suggests practical approaches for using READ Scale data. © Bella Karr Gerlich

    About the dynamics and thermodynamics of trapped ions

    Full text link
    This tutorial introduces the dynamics of charged particles in a radiofrequency trap in a very general manner to point out the differences between the dynamics in a quadrupole and in a multipole trap. When dense samples are trapped, the dynamics is modified by the Coulomb repulsion between ions. To take into account this repulsion, we propose to use a method, originally developed for particles in Penning trap, that model the ion cloud as a cold fluid. This method can not reproduce the organisation of cold clouds as crystals but it allows one to scale the size of large samples with the trapping parameters and the number of ions trapped, for different linear geometries of trap.Comment: accepted for publication in the "Modern Applications of Trapped Ions" special issu

    Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics

    Full text link
    The atmospheric greenhouse effect, an idea that many authors trace back to the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896), and which is still supported in global climatology, essentially describes a fictitious mechanism, in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected

    Electronic structure of the Magnesium hydride molecular ion

    Full text link
    In this paper, using a standard quantum chemistry approach based on pseudopotentials for atomic core representation, Gaussian basis sets, and effective core polarization potentials, we investigate the electronic properties of the MgH+^+ ion. We first determine potential energy curves for several states using different basis sets and discuss their predicted accuracy by comparing our values of the well depths and position with other available results. We then calculate permanent and transition dipole moments for several transitions. Finally for the first time, we calculate the static dipole polarizability of MgH+^+ as function of the interatomic distance. This study represents the first step towards the modeling of collisions between trapped cold Mg+^+ ions and H2_2 molecules.Comment: submitted to J. Phys. B, special issue on Cold trapped ion

    Illusory Decoherence

    Full text link
    If a quantum experiment includes random processes, then the results of repeated measurements can appear consistent with irreversible decoherence even if the system's evolution prior to measurement was reversible and unitary. Two thought experiments are constructed as examples.Comment: 10 pages, 3 figure

    Detection and treatment of HIV and hepatitis virus infections in Swiss correctional facilities

    Full text link
    OBJECTIVES: The aim of the study was to obtain an overview on diagnostic and therapeutic activities concerning hepatitis A, B, C virus and HIV in Swiss prisons.METHODS: A standardized questionnaire was sent to 91 prisons in the German and Italian speaking parts in October 2004; 41 institutions (45%) answered the questionnaire.RESULTS: In almost all prisons serological examinations were not done routinely, but were provided when demanded by inmates or recommended by the medical service. Vaccination against hepatitis A or B infection and initiation of antiviral therapy was possible in most institutions.CONCLUSIONS: Most of the prisons investigated offered diagnostic and antiviral treatment for hepatitis virus and HIV infections. A reported problem was the discontinuation of ongoing treatments or vaccination cycles after discharge. In some cases deficient funding was an obstacle

    A linear radiofrequency ion trap for accumulation, bunching, and emittance improvement of radioactive ion beams

    Get PDF
    An ion beam cooler and buncher has been developed for the manipulation of radioactive ion beams. The gas-filled linear radiofrequency ion trap system is installed at the Penning trap mass spectrometer ISOLTRAP at ISOLDE/CERN. Its purpose is to accumulate the 60-keV continuous ISOLDE ion beam with high efficiency and to convert it into low-energy low-emittance ion pulses. The efficiency was found to exceed 10% in agreement with simulations. A more than 10-fold reduction of the ISOLDE beam emittance can be achieved. The system has been used successfully for first on-line experiments. Its principle, setup and performance will be discussed

    Modes of Oscillation in Radiofrequency Paul Traps

    Full text link
    We examine the time-dependent dynamics of ion crystals in radiofrequency traps. The problem of stable trapping of general three-dimensional crystals is considered and the validity of the pseudopotential approximation is discussed. We derive analytically the micromotion amplitude of the ions, rigorously proving well-known experimental observations. We use a method of infinite determinants to find the modes which diagonalize the linearized time-dependent dynamical problem. This allows obtaining explicitly the ('Floquet-Lyapunov') transformation to coordinates of decoupled linear oscillators. We demonstrate the utility of the method by analyzing the modes of a small `peculiar' crystal in a linear Paul trap. The calculations can be readily generalized to multispecies ion crystals in general multipole traps, and time-dependent quantum wavefunctions of ion oscillations in such traps can be obtained.Comment: 24 pages, 3 figures, v2 adds citations and small correction

    Colloquium: Quantum interference of clusters and molecules

    Full text link
    We review recent progress and future prospects of matter wave interferometry with complex organic molecules and inorganic clusters. Three variants of a near-field interference effect, based on diffraction by material nanostructures, at optical phase gratings, and at ionizing laser fields are considered. We discuss the theoretical concepts underlying these experiments and the experimental challenges. This includes optimizing interferometer designs as well as understanding the role of decoherence. The high sensitivity of matter wave interference experiments to external perturbations is demonstrated to be useful for accurately measuring internal properties of delocalized nanoparticles. We conclude by investigating the prospects for probing the quantum superposition principle in the limit of high particle mass and complexity.Comment: 19 pages, 13 figures; v2: corresponds to published versio
    • …
    corecore