1,762 research outputs found
Research and development of high temperature resistant polymeric film forming material final summary report, 1 mar. 1961 - 17 apr. 1962
Preparation of poly-organometallosiloxane polymers from reactions between bis-dialkylamino metal derivatives and silanediol
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Is tertiary education in dire straits? (Is it money for nothing of just another brick in the wall?)
Establishing the pattern of the vertebrate limb
The vertebrate limb continues to serve as an influential model of growth, morphogenesis and pattern formation. With this Review, we aim to give an up-to-date picture of how a population of undifferentiated cells develops into the complex pattern of the limb. Focussing largely on mouse and chick studies, we concentrate on the positioning of the limbs, the formation of the limb bud, the establishment of the principal limb axes, the specification of pattern, the integration of pattern formation with growth and the determination of digit number. We also discuss the important, but little understood, topic of how gene expression is interpreted into morphology
Sonic hedgehog-expressing cells in the developing limb measure time by an intrinsic cell cycle clock
How time is measured is an enduring issue in developmental biology. Classical models of somitogenesis and limb development implicated intrinsic cell cycle clocks, but their existence remains controversial. Here we show that an intrinsic cell cycle clock in polarizing region cells of the chick limb bud times the duration of Sonic hedgehog (Shh) expression, which encodes the morphogen specifying digit pattern across the antero-posterior axis (thumb to little finger). Timing by this clock starts when polarizing region cells fall out of range of retinoic acid signalling. We found that timing of Shh transcription by the cell cycle clock can be reset, thus revealing an embryonic form of self-renewal. In contrast, antero-posterior positional values cannot be reset, suggesting that this may be an important constraint on digit regeneration. Our findings provide the first evidence for an intrinsic cell cycle timer controlling duration and patterning activity of a major embryonic signalling centre
An Evaluation of the Impact of the Social Care Modernisation Programme on the Implementation of Direct Payments London
A Water Maser and Ammonia Survey of GLIMPSE Extended Green Objects (EGOs)
We present the results of a Nobeyama 45-m water maser and ammonia survey of
all 94 northern GLIMPSE Extended Green Objects (EGOs), a sample of massive
young stellar objects (MYSOs) identified based on their extended 4.5 micron
emission. We observed the ammonia (1,1), (2,2), and (3,3) inversion lines, and
detect emission towards 97%, 63%, and 46% of our sample, respectively (median
rms ~50 mK). The water maser detection rate is 68% (median rms ~0.11 Jy). The
derived water maser and clump-scale gas properties are consistent with the
identification of EGOs as young MYSOs. To explore the degree of variation among
EGOs, we analyze subsamples defined based on MIR properties or maser
associations. Water masers and warm dense gas, as indicated by emission in the
higher-excitation ammonia transitions, are most frequently detected towards
EGOs also associated with both Class I and II methanol masers. 95% (81%) of
such EGOs are detected in water (ammonia(3,3)), compared to only 33% (7%) of
EGOs without either methanol maser type. As populations, EGOs associated with
Class I and/or II methanol masers have significantly higher ammonia linewidths,
column densities, and kinetic temperatures than EGOs undetected in methanol
maser surveys. However, we find no evidence for statistically significant
differences in water maser properties (such as maser luminosity) among any EGO
subsamples. Combining our data with the 1.1 mm continuum Bolocam Galactic Plane
Survey, we find no correlation between isotropic water maser luminosity and
clump number density. Water maser luminosity is weakly correlated with clump
(gas) temperature and clump mass.Comment: Astrophysical Journal, accepted. Emulateapj, 24 pages including 24
figures, plus 9 tables (including full content of online-only tables
Stable three-dimensional spinning optical solitons supported by competing quadratic and cubic nonlinearities
We show that the quadratic interaction of fundamental and second harmonics in
a bulk dispersive medium, combined with self-defocusing cubic nonlinearity,
give rise to completely localized spatiotemporal solitons (vortex tori) with
vorticity s=1. There is no threshold necessary for the existence of these
solitons. They are found to be stable against small perturbations if their
energy exceeds a certain critical value, so that the stability domain occupies
about 10% of the existence region of the solitons. We also demonstrate that the
s=1 solitons are stable against very strong perturbations initially added to
them. However, on the contrary to spatial vortex solitons in the same model,
the spatiotemporal solitons with s=2 are never stable.Comment: latex text, 10 ps and 2 jpg figures; Physical Review E, in pres
Application of the Feshbach-resonance management to a tightly confined Bose-Einstein condensate
We study suppression of the collapse and stabilization of matter-wave
solitons by means of time-periodic modulation of the effective nonlinearity,
using the nonpolynomial Schroedinger equation (NPSE) for BEC trapped in a tight
cigar-shaped potential. By means of systematic simulations, a stability region
is identified in the plane of the modulation amplitude and frequency. In the
low-frequency regime, solitons feature chaotic evolution, although they remain
robust objects.Comment: Physical Review A, in pres
Moral injury in veterans : a theoretical investigation of the psychic, moral and social sequelae of war trauma
Although the idea that a violation of deeply held moral and ethical values can result in a profound psychic, social and spiritual wounding is an ancient one, the exploration of the phenomenon of moral injury in the field of mental health has only recently gained traction. Moral injury is increasingly being regarded as its own psychological phenomenon, one that shares symptomology with PTSD, but is also distinct, and as yet not sufficiently accounted for in current PTSD criteria. This theoretical thesis charts the evolving clinical construct of moral injury and draws on two bodies of theory, narrative theory and adult onset trauma theory, to further explore the psychic and social sequelae of war trauma. The work of the public health project Theater of War, and the text of Sophocles’ Ajax are used as case examples to illustrate the treatment implications for social work practice of applying narrative theory and adult onset trauma to moral injury
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