626 research outputs found
Content Validation of a Questionnaire to Measure Digital Competence of Nurses in Clinical Practice
Clinical practice nurses need adequate digital competence to use technologies appropriately at work. Questionnaires measuring clinical practice nurses' digital competence lack content validity because attitude is not included as a measure of digital competence. The aim of the current study was to identify items for an item pool of a questionnaire to measure clinical practice nurses' digital competence and to evaluate the content validity. A normative Delphi study was conducted, and the content validity index on item and scale levels was calculated. In each round, 21 to 24 panelists (medical informatics specialists, nurse informatics specialists, digital managers, and researchers) were asked to rate the items on a 4-point Likert scale ranging from “not relevant” to “very relevant.” Within three rounds, the panelists reached high consensus and rated 26 items of the initial 37 items as relevant. The average content validity index of 0.95 (SD, 0.07) demonstrates that the item pool showed high content validity. The final item pool included items to measure knowledge, skills, and attitude. The items included represent the international recommendations of core competences for clinical nursing. Future research should conduct psychometric testing for construct validity and internal consistency of the generated item pool
Chickadee songs provide hidden clues to singers’ locations
Funding: LMG was supported by an Izaak Walton Killam Memorial Scholarship (IWKMS) at UofA and is currently a BBSRC Anniversary Future Leader Fellow.Coordination of actions requires that organisms actively monitor the movements of others. The current study examined acoustic cues within the fee-bee song of chickadees that may provide listening conspecifics with information about the movements of singers. The difference between direct and reverberant acoustic energy present during the second note of the fee-bee song provided clear indications of how far the song had traveled. Preliminary analyses suggest that this distance cue may be robust to variations in the spectra and amplitude of song components,and that the acoustic features of the fee-bee song may facilitate simultaneous comparisons of reverberating fees with directly received bees by listening birds. Comparing coincident reverberation with directly received sounds may be a previously unsuspected way that animals living in reverberant environments can monitor the movements and interactions of conspecifics.Publisher PDFPeer reviewe
Stochastic Calculus for a Time-changed Semimartingale and the Associated Stochastic Differential Equations
It is shown that under a certain condition on a semimartingale and a
time-change, any stochastic integral driven by the time-changed semimartingale
is a time-changed stochastic integral driven by the original semimartingale. As
a direct consequence, a specialized form of the Ito formula is derived. When a
standard Brownian motion is the original semimartingale, classical Ito
stochastic differential equations driven by the Brownian motion with drift
extend to a larger class of stochastic differential equations involving a
time-change with continuous paths. A form of the general solution of linear
equations in this new class is established, followed by consideration of some
examples analogous to the classical equations. Through these examples, each
coefficient of the stochastic differential equations in the new class is given
meaning. The new feature is the coexistence of a usual drift term along with a
term related to the time-change.Comment: 27 pages; typos correcte
The X10 Flare on 2003 October 29: Triggered by Magnetic Reconnection between Counter-Helical Fluxes?
Vector magnetograms taken at Huairou Solar Observing Station (HSOS) and Mees
Solar Observatory (MSO) reveal that the super active region (AR) NOAA 10486 was
a complex region containing current helicity flux of opposite signs. The main
positive sunspots were dominated by negative helicity fields, while positive
helicity patches persisted both inside and around the main positive sunspots.
Based on a comparison of two days of deduced current helicity density,
pronounced changes were noticed which were associated with the occurrence of an
X10 flare that peaked at 20:49 UT, 2003 October 29. The average current
helicity density (negative) of the main sunspots decreased significantly by
about 50. Accordingly, the helicity densities of counter-helical patches
(positive) were also found to decay by the same proportion or more. In
addition, two hard X-ray (HXR) `footpoints' were observed by the Reuven Ramaty
High Energy Solar Spectroscopic Imager (RHESSI} during the flare in the 50-100
keV energy range. The cores of these two HXR footpoints were adjacent to the
positions of two patches with positive current helicity which disappeared after
the flare. This strongly suggested that the X10 flare on 2003 Oct. 29 resulted
from reconnection between magnetic flux tubes having opposite current helicity.
Finally, the global decrease of current helicity in AR 10486 by ~50% can be
understood as the helicity launched away by the halo coronal mass ejection
(CME) associated with the X10 flare.Comment: Solar Physics, 2007, in pres
A probabilistic model for gene content evolution with duplication, loss, and horizontal transfer
We introduce a Markov model for the evolution of a gene family along a
phylogeny. The model includes parameters for the rates of horizontal gene
transfer, gene duplication, and gene loss, in addition to branch lengths in the
phylogeny. The likelihood for the changes in the size of a gene family across
different organisms can be calculated in O(N+hM^2) time and O(N+M^2) space,
where N is the number of organisms, is the height of the phylogeny, and M
is the sum of family sizes. We apply the model to the evolution of gene content
in Preoteobacteria using the gene families in the COG (Clusters of Orthologous
Groups) database
Semiparametric theory and empirical processes in causal inference
In this paper we review important aspects of semiparametric theory and
empirical processes that arise in causal inference problems. We begin with a
brief introduction to the general problem of causal inference, and go on to
discuss estimation and inference for causal effects under semiparametric
models, which allow parts of the data-generating process to be unrestricted if
they are not of particular interest (i.e., nuisance functions). These models
are very useful in causal problems because the outcome process is often complex
and difficult to model, and there may only be information available about the
treatment process (at best). Semiparametric theory gives a framework for
benchmarking efficiency and constructing estimators in such settings. In the
second part of the paper we discuss empirical process theory, which provides
powerful tools for understanding the asymptotic behavior of semiparametric
estimators that depend on flexible nonparametric estimators of nuisance
functions. These tools are crucial for incorporating machine learning and other
modern methods into causal inference analyses. We conclude by examining related
extensions and future directions for work in semiparametric causal inference
Origins of the Ambient Solar Wind: Implications for Space Weather
The Sun's outer atmosphere is heated to temperatures of millions of degrees,
and solar plasma flows out into interplanetary space at supersonic speeds. This
paper reviews our current understanding of these interrelated problems: coronal
heating and the acceleration of the ambient solar wind. We also discuss where
the community stands in its ability to forecast how variations in the solar
wind (i.e., fast and slow wind streams) impact the Earth. Although the last few
decades have seen significant progress in observations and modeling, we still
do not have a complete understanding of the relevant physical processes, nor do
we have a quantitatively precise census of which coronal structures contribute
to specific types of solar wind. Fast streams are known to be connected to the
central regions of large coronal holes. Slow streams, however, appear to come
from a wide range of sources, including streamers, pseudostreamers, coronal
loops, active regions, and coronal hole boundaries. Complicating our
understanding even more is the fact that processes such as turbulence,
stream-stream interactions, and Coulomb collisions can make it difficult to
unambiguously map a parcel measured at 1 AU back down to its coronal source. We
also review recent progress -- in theoretical modeling, observational data
analysis, and forecasting techniques that sit at the interface between data and
theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue
connected with a 2016 ISSI workshop on "The Scientific Foundations of Space
Weather." 44 pages, 9 figure
Global Search for New Physics with 2.0/fb at CDF
Data collected in Run II of the Fermilab Tevatron are searched for
indications of new electroweak-scale physics. Rather than focusing on
particular new physics scenarios, CDF data are analyzed for discrepancies with
the standard model prediction. A model-independent approach (Vista) considers
gross features of the data, and is sensitive to new large cross-section
physics. Further sensitivity to new physics is provided by two additional
algorithms: a Bump Hunter searches invariant mass distributions for "bumps"
that could indicate resonant production of new particles; and the Sleuth
procedure scans for data excesses at large summed transverse momentum. This
combined global search for new physics in 2.0/fb of ppbar collisions at
sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D
Rapid Communication
Observation of Orbitally Excited B_s Mesons
We report the first observation of two narrow resonances consistent with
states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar
collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the
Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed
as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+,
\bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1})
= 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let
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