779 research outputs found
Introducing the READ Scale: Qualitative Statistics for Academic Reference Services
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
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
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
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
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 H molecules.Comment: submitted to J. Phys. B, special issue on Cold trapped ion
Illusory Decoherence
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
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
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
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
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
- …