1,117 research outputs found
Taking a “Deep Dive”: What Only a Top Leader Can Do
Unlike most historical accounts of strategic change inside large firms, empirical research on strategic management rarely uses the day-to-day behaviors of top executives as the unit of analysis. By examining the resource allocation process closely, we introduce the concept of a deep dive, an intervention when top management seizes hold of the substantive content of a strategic initiative and its operational implementation at the project level, as a way to drive new behaviors that enable an organization to shift its performance trajectory into new dimensions unreachable with any of the previously described forms of intervention. We illustrate the power of this previously underexplored change mechanism with a case study, in which a well-established firm overcame barriers to change that were manifest in a wide range of organizational routines and behavioral norms that had been fostered by the pre-existing structural context of the firm.Strategic Change, Resource Allocation Process, Top-down Intervention
How young are early-type cluster galaxies ? Quantifying the young stellar component in a rich cluster at z=0.41
We present a new method of quantifying the mass fraction of young stars in
galaxies by analyzing near-ultraviolet (NUV)-optical colors. We focus our
attention on early-type cluster galaxies, whose star formation history is at
present undetermined. Rest-frame NUV (F300W) and optical (F702W) images of
cluster Abell 851 (z=0.41) using HST/WFPC2 allow us to determine a NUV-optical
color-magnitude relation, whose slope is incompatible with a monolithic
scenario for star formation at high redshift. A degeneracy between a young
stellar component and its fractional mass contribution to the galaxy is found,
and a photometric analysis comparing the data with the predictions for a simple
two-stage star formation history is presented. The analysis shows that some of
the early-type galaxies may have fractions higher than 10% of the total mass
content in stars formed at z~0.5. An increased scatter is found in the
color-magnitude relation at the faint end, resulting in a significant fraction
of faint blue early-type systems. This would imply that less massive galaxies
undergo more recent episodes of star formation, and this can be explained in
terms of a positive correlation between star formation efficiency and
luminosity.Comment: Accepted for publication in ApJ Letters. Uses emulateapj.sty. 5 pages
with 3 embedded EPS figure
A qualitative, exploratory study of nurses’ decision-making when interrupted during medication administration within the Paediatric Intensive Care Unit
ObjectiveIn the paediatric intensive care unit (PICU), medication administration is challenging. Empirical studies demonstrate that interruptions occur frequently and that nurses are fundamental in the delivery of medication. However, little is known about nurse’s decision making when interrupted during medication administration. Therefore, the objective is to understand decision making when interrupted during medication administration within the PICU.Research designA qualitative study incorporating non-participant observation and audio recorded semi-structured interviews. A convenience sample of ten PICU nurses were interviewed. Each interview schedule was informed by two hours of observation which involved a further 29 PICU nurses. Data was analysed using Framework Analysis.SettingA regional PICU located in a university teaching hospital in the United Kingdom.FindingsAnalysis resulted in four overarching themes:(1) Guiding the medication process,(2) Concentration, focus and awareness,(3) Influences on interruptions(4) Impact and recoveryConclusionMedication administration within the PICU is an essential but complex activity. Interruptions can impact on focus and concentration which can contribute to patient harm. Decision making by PICU nurses is influenced by interruption awareness, fluctuating levels of concentration, and responding to critically ill patient and families’ needs
Gamma-ray emission from dark matter wakes of recoiled black holes
A new scenario for the emission of high-energy gamma-rays from dark matter
annihilation around massive black holes is presented. A black hole can leave
its parent halo, by means of gravitational radiation recoil, in a merger event
or in the asymmetric collapse of its progenitor star. A recoiled black hole
which moves on an almost-radial orbit outside the virial radius of its central
halo, in the cold dark matter background, reaches its apapsis in a finite time.
Near or at the apapsis passage, a high-density wake extending over a large
radius of influence, forms around the black hole. It is shown that significant
gamma-ray emission can result from the enhancement of neutralino annihilation
in these wakes. At its apapsis passage, a black hole is shown to produce a
flash of high-energy gamma-rays whose duration is determined by the mass of the
black hole and the redshift at which it is ejected. The ensemble of such black
holes in the Hubble volume is shown to produce a diffuse high-energy gamma-ray
background whose magnitude is compared to the diffuse emission from dark matter
haloes alone.Comment: version to appear in Astrophysical Journal letters (labels on Fig. 3
corrected
Galactic Center Pulsars with the ngVLA
Pulsars in the Galactic Center (GC) are important probes of General
Relativity, star formation, stellar dynamics, stellar evolution, and the
interstellar medium. Despite years of searching, only a handful of pulsars in
the central 0.5 deg are known. The high-frequency sensitivity of ngVLA will
open a new window for discovery and characterization of pulsars in the GC. A
pulsar in orbit around the GC black hole, Sgr A*, will provide an unprecedented
probe of black hole physics and General Relativity.Comment: To be published in the ASP Monograph Series, "Science with a
Next-Generation VLA", ed. E. J. Murphy (ASP, San Francisco, CA
A Millisecond Interferometric Search for Fast Radio Bursts with the Very Large Array
We report on the first millisecond timescale radio interferometric search for
the new class of transient known as fast radio bursts (FRBs). We used the Very
Large Array (VLA) for a 166-hour, millisecond imaging campaign to detect and
precisely localize an FRB. We observed at 1.4 GHz and produced visibilities
with 5 ms time resolution over 256 MHz of bandwidth. Dedispersed images were
searched for transients with dispersion measures from 0 to 3000 pc/cm3. No
transients were detected in observations of high Galactic latitude fields taken
from September 2013 though October 2014. Observations of a known pulsar show
that images typically had a thermal-noise limited sensitivity of 120 mJy/beam
(8 sigma; Stokes I) in 5 ms and could detect and localize transients over a
wide field of view. Our nondetection limits the FRB rate to less than
7e4/sky/day (95% confidence) above a fluence limit of 1.2 Jy-ms. Assuming a
Euclidean flux distribution, the VLA rate limit is inconsistent with the
published rate of Thornton et al. We recalculate previously published rates
with a homogeneous consideration of the effects of primary beam attenuation,
dispersion, pulse width, and sky brightness. This revises the FRB rate downward
and shows that the VLA observations had a roughly 60% chance of detecting a
typical FRB and that a 95% confidence constraint would require roughly 500
hours of similar VLA observing. Our survey also limits the repetition rate of
an FRB to 2 times less than any known repeating millisecond radio transient.Comment: Submitted to ApJ. 13 pages, 9 figure
Detection of Evolved High-Redshift Galaxies in Deep NICMOS/VLT Images
A substantial population of high redshift early-type galaxies is detected in
very deep UBVRIJHK images towards the HDF-South. Four elliptical profile
galaxies are identified in the redshift range z=1-2, all with very red SEDs,
implying ages of >2 Gyrs for standard passive evolution. We also find later
type IR-luminous galaxies at similarly high redshift, (10 objects with z>1,
H1 Gyr. The number
and luminosity-densities of these galaxies are comparable with the local
E/SO-Sbc populations for \Omega_m>0.2, and in the absence of a significant
cosmological constant, we infer that the major fraction of luminous
Hubble-sequence galaxies have evolved little since z~2. A highly complete
photometric redshift distribution is constructed to H=25 (69 galaxies) showing
a broad spread of redshift, peaking at z~1.5, in reasonable agreement with some
analyses of the HDF. Five `dropout' galaxies are detected at z~3.8, which are
compact in the IR, ~0.5 kpc/h at rest 3500\AA. No example of a blue IR luminous
elliptical is found, restricting the star-formation epoch of ellipticals to
z>10 for a standard IMF and modest extinction.Comment: 7 pages, 3 figures, accepted for publication in Astrophysical Journal
Letters, discussion of clustering added, color image available at
http://astro.berkeley.edu/~tjb/nic3.htm
Inappropriate Antidiuresis: Examples of an Hyponatremic Syndrome Resembling Exogenous Vasopressin Administration in Man
We have reviewed some of the features of hyponatremic syndromes, unassociated with sodium retention and edema, but associated with primary water retention. The syndromes were probably caused by excessive vasopressin activity, in the presence of normal circulatory, renal and adreno-cortical function. Underlying diseases, including bronchogenic carcinoma, head injury, and tuberculous meningitis, illustrated the diverse etiologic bases of this condition
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