138 research outputs found
O081: Reduction of clostridium difficile infections with enhanced evidence-based practices and antimicrobial stewardship
A comprehensive study of Cepheid variables in the Andromeda galaxy. Period distribution, blending and distance determination
Extragalactic Cepheids are the basic rungs of the cosmic distance scale. They
are excellent standard candles, although their luminosities and corresponding
distance estimates can be affected by the particular properties of the host
galaxy. Therefore, the accurate analysis of the Cepheid population in other
galaxies, and notably in the Andromeda Galaxy (M31), is crucial to obtaining
reliable distance determinations. We obtained accurate photometry (in B and V
passbands) of 416 Cepheids in M31 over a five year campaign within a survey
aimed at the detection of eclipsing binaries. The resulting Cepheid sample is
the most complete in M31 and has almost the same period distribution as the
David Dunlap Observatory sample in the Milky Way. The large number of epochs
(~250 per filter) has permitted the characterisation of the pulsation modes of
356 Cepheids, with 281 of them pulsating in the fundamental mode and 75 in the
first overtone. The period-luminosity relationship of the fundamental mode
Cepheids has been studied and a new approach has been used to estimate the
effect of blending. We find that the blending contribution is as important as
the metallicity correction when computing Cepheid distance determinations to
M31 (~0.1 mag). Since large amplitude Cepheids are less affected by blending,
we have used those with an amplitude A_V>0.8 mag to derive a distance to M31 of
(m-M)_0=24.32+/-0.12 mag.Comment: 10 pages, 9 figures; accepted for publication in A&
Neural Computation via Neural Geometry: A Place Code for Inter-whisker Timing in the Barrel Cortex?
The place theory proposed by Jeffress (1948) is still the dominant model of how the brain represents the movement of sensory stimuli between sensory receptors. According to the place theory, delays in signalling between neurons, dependent on the distances between them, compensate for time differences in the stimulation of sensory receptors. Hence the location of neurons, activated by the coincident arrival of multiple signals, reports the stimulus movement velocity. Despite its generality, most evidence for the place theory has been provided by studies of the auditory system of auditory specialists like the barn owl, but in the study of mammalian auditory systems the evidence is inconclusive. We ask to what extent the somatosensory systems of tactile specialists like rats and mice use distance dependent delays between neurons to compute the motion of tactile stimuli between the facial whiskers (or âvibrissaeâ). We present a model in which synaptic inputs evoked by whisker deflections arrive at neurons in layer 2/3 (L2/3) somatosensory âbarrelâ cortex at different times. The timing of synaptic inputs to each neuron depends on its location relative to sources of input in layer 4 (L4) that represent stimulation of each whisker. Constrained by the geometry and timing of projections from L4 to L2/3, the model can account for a range of experimentally measured responses to two-whisker stimuli. Consistent with that data, responses of model neurons located between the barrels to paired stimulation of two whiskers are greater than the sum of the responses to either whisker input alone. The model predicts that for neurons located closer to either barrel these supralinear responses are tuned for longer inter-whisker stimulation intervals, yielding a topographic map for the inter-whisker deflection interval across the surface of L2/3. This map constitutes a neural place code for the relative timing of sensory stimuli
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Beyond handover: supporting awareness for continuous coverage
Abstract Hospitals are required to operate as a continuous system because patient care cannot be temporarily suspended and handover is seen as a key method for enabling this. This paper reports a study of handover in a medical admissions unit. We draw on the notion of awareness as conceptualised within the Computer Supported Cooperative Work literature to explore the role played by a variety of cognitive artifacts in supporting continuous coverage. While such awareness is typically characterised as being âeffortlessâ, our study reveals that maintaining awareness in a context such as the medical admissions unit is effortful due to invisible work. We suggest that the notion of awareness is beneficial for exploring the practices of continuous coverage because it moves attention away from the moment of handover, instead encouraging consideration of the variety of practices through which clinicians display their work to, and monitor the work of, colleagues on different shifts. We argue that efforts to support continuous coverage should focus on improving awareness by increasing the visibility of information
Nonparametric IRT analysis of Quality-of-Life Scales and its application to the World Health Organization Quality-of-Life Scale (WHOQOL-Bref)
Clinimetric evaluation of active range of motion measures in patients with non-specific neck pain: a systematic review
The study is to provide a critical analysis of the research literature on clinimetric properties of instruments that can be used in daily practice to measure active cervical range of motion (ACROM) in patients with non-specific neck pain. A computerized literature search was performed in Medline, Cinahl and Embase from 1982 to January 2007. Two reviewers independently assessed the clinimetric properties of identified instruments using a criteria list. The search identified a total of 33 studies, investigating three different types of measurement instruments to determine ACROM. These instruments were: (1) different types of goniometers/inclinometers, (2) visual estimation, and (3) tape measurements. Intra- and inter-observer reliability was demonstrated for the cervical range of motion instrument (CROM), Cybex electronic digital instrument (EDI-320) and a single inclinometer. The presence of agreement was assessed for the EDI-320 and a single inclinometer. The CROM received a positive rating for construct validity. When clinical acceptability is taken into account both the CROM and the single inclinometer can be considered appropriate instruments for measuring the active range of motion in patients with non-specific neck pain in daily practice. Reliability is the aspect most frequently evaluated. Agreement, validity and responsiveness are documented less frequently
Spectroscopic Survey of the Galaxy with Gaia II. The expected science yield from the Radial Velocity Spectrometer
The Gaia mission is designed as a Galaxy explorer, and will measure
simultaneously, in a survey mode, the five or six phase space parameters of all
stars brighter than 20th magnitude, as well as providing a description of their
astrophysical characteristics. These measurements are obtained by combining an
astrometric instrument with micro-arcsecond capabilities, a photometric system
giving the magnitudes and colours in 15 bands and a medium resolution
spectrograph named the Radial Velocity Spectrometer (RVS). The latter
instrument will produce spectra in the 848 to 874 nm wavelength range, with a
resolving power R = 11 500, from which radial velocities, rotational
velocities, atmospheric parameters and abundances can be derived. A companion
paper (Katz et al. 2004) presents the characteristics of the RVS and its
performance. This paper details the outstanding scientific impact of this
important part of the Gaia satellite on some key open questions in present day
astrophysics. The unbiased and simultaneous acquisition of multi-epoch radial
velocities and individual abundances of key elements in parallel with the
astrometric parameters is essential for the determination of the dynamical
state and formation history of our Galaxy. Moreover, for stars brighter than
V=15, the resolving power of the RVS will give information about most of the
effects which influence the position of a star in the Hertzsprung-Russell
diagram, placing unprecedented constraints on the age, internal structure and
evolution of stars of all types. Finally, the RVS multi-epoch observations are
ideally suited to the identification, classification and characterisation of
the many types of double, multiple and variable stars.Comment: 33 pages, 11 figures, in press at MNRAS. Figs 1, 3 and 9 included at
reduced resolution; available in full resolution at
http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-2966.2005.09012.
Dense sampling of bird diversity increases power of comparative genomics (vol 587, pg 252, 2020)
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A search for ttÌ resonances using lepton-plus-jets events in proton-proton collisions at âs = 8 TeV with the ATLAS detector
A search for new particles that decay into top quark pairs is reported. The search is performed with the ATLAS experiment at the LHC using an integrated luminosity of 20.3 fbâÂč of proton-proton collision data collected at a centre-of-mass energy of âs=8 TeV. The lepton-plus-jets final state is used, where the top pair decays to W+bWâbÌ, with one W boson decaying leptonically and the other hadronically. The invariant mass spectrum of top quark pairs is examined for local excesses or deficits that are inconsistent with the Standard Model predictions. No evidence for a top quark pair resonance is found, and 95% confidence-level limits on the production rate are determined for massive states in benchmark models. The upper limits on the cross-section times branching ratio of a narrow ZâČ boson decaying to top pairs range from 4.2 pb to 0.03 pb for resonance masses from 0.4 TeV to 3.0 TeV. A narrow leptophobic topcolour ZâČ boson with mass below 1.8 TeV is excluded. Upper limits are set on the cross-section times branching ratio for a broad colour-octet resonance with Î/m = 15% decaying to ttÌ. These range from 4.8 pb to 0.03 pb for masses from 0.4 TeV to 3.0 TeV. A Kaluza-Klein excitation of the gluon in a Randall-Sundrum model is excluded for masses below 2.2 TeV
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