6,747 research outputs found
The characteristics of the flow field over the mid-upper fuselage of Lancaster P. A. 474
This note describes a series of tests conducted to determine the
characteristics of the flow field over the mid-upper fuselage of.
Lancaster P. A, 474.
The range of the tests was to include a determination of the distributions
of total head, static pressure and velocity together with
the flow directional characteristics in the pitching plane for a
number of aircraft flight configurations as listed in paragraph 1. 2.
Curves are presented in Figs. 9, 20 - 25, showing the flow directional
characteristics and the distributions of static pressure and velocity
in the region of investigation
Many-Body Corrections to Charged-Current Neutrino Absorption Rates in Nuclear Matter
Including nucleon--nucleon correlations due to both Fermi statistics and
nuclear forces, we have developed a general formalism for calculating the
charged--current neutrino--nucleon absorption rates in nuclear matter. We find
that at one half nuclear density many--body effects alone suppress the rates by
a factor of two and that the suppression factors increase to 5 at
g cm. The associated increase in the neutrino--matter
mean--free--paths parallels that found for neutral--current interactions and
opens up interesting possibilities in the context of the delayed supernova
mechanism and protoneutron star cooling.Comment: 11 pages, APS REVTeX format, 1 PostScript figure, uuencoded
compressed, and tarred, submitted to Physical Review Letter
A Theory for the Radius of the Transiting Giant Planet HD 209458b
Using a full frequency-dependent atmosphere code that can incorporate
irradiation by a central primary star, we calculate self-consistent boundary
conditions for the evolution of the radius of the transiting planet HD 209458b.
Using a well-tested extrasolar giant planet evolutionary code, we then
calculate the behavior of this planet's radius with age. The measured radius is
in fact a transit radius that resides high in HD 209458b's inflated atmosphere.
Using our derived atmospheric and interior structures, we find that irradiation
plus the proper interpretation of the transit radius can yield a theoretical
radius that is within the measured error bars. We conclude that if HD 209458b's
true transit radius is at the lower end of the measured range, an extra source
of core heating power is not necessary to explain the transit observations.Comment: 6 pages in emulateapj format, plus 2 figures (one color), accepted to
the Astrophysical Journa
Consideraciones diagnĂłsticas sobre la diarrea crĂłnica en el perro y en el gato
En el presente artĂculo se discute el protocolo a seguir para llegar al diagnĂłstico etiolĂłgico de un proceso diarreico crĂłnico en un perro o en un gato.In this article a discussion is presented on the protocol to be followed to reach an aetiological diagnosis of chronic diarrhoea in dogs or cats
Exploring patient and family satisfaction in pediatric neurological surgery
Introduction Patient and family satisfaction during outpatient visits is correlated with a continuance of care and likelihood to recommend the practice to others. Additionally, patient-family satisfaction can determine the success of the practice and influence medical outcomes. Utilizing a well-validated surveys instrument, patient and family satisfaction can be explored in the office setting. Methods During a consecutive 36 month period, a standardized and validated patient satisfaction survey instrument was provided to the family members of patients who presented to two pediatric neurosurgery clinics associated with Nemours Children\u27s Health System. The completed surveys were analyzed statistically to identify correlations between overall satisfaction, defined as âLikelihood to Recommend (LTR) the Practiceâ, and relevant practice and provider variables. Results The factors that exhibited the greatest correlation to LTR were: âCheerfulness of Practiceâ (r = 0.74), âAbility to Get Desired Appointmentâ (r = 0.70), âLikelihood of Recommending Care Providerâ (r = 0.65), âStaff Worked Togetherâ (r = 0.65), and âWaiting Area Comfort and Pleasantnessâ (r = 0.60). Discussion and conclusions Patient and family satisfaction surveys are useful for gaining insight into pediatric neurosurgical practices. Data from this cohort suggest that the environment in which patient care is delivered, timeliness of appointments and positive perceptions of the healthcare team correlate most strongly with overall satisfaction. © 201
Strong Water Absorption in the Dayside Emission Spectrum of the Planet HD 189733b
Recent observations of the extrasolar planet HD 189733b did not reveal the
presence of water in the emission spectrum of the planet. Yet models of such
'Hot Jupiter' planets predict an abundance of atmospheric water vapour.
Validating and constraining these models is crucial for understanding the
physics and chemistry of planetary atmospheres in extreme environments.
Indications of the presence of water in the atmosphere of HD 189733b have
recently been found in transmission spectra, where the planet's atmosphere
selectively absorbs the light of the parent star, and in broadband photometry.
Here we report on the detection of strong water absorption in a high
signal-to-noise, mid-infrared emission spectrum of the planet itself. We find
both a strong downturn in the flux ratio below 10 microns and discrete spectral
features that are characteristic of strong absorption by water vapour. The
differences between these and previous observations are significant and admit
the possibility that predicted planetary-scale dynamical weather structures
might alter the emission spectrum over time. Models that match the observed
spectrum and the broadband photometry suggest that heat distribution from the
dayside to the night side is weak. Reconciling this with the high night side
temperature will require a better understanding of atmospheric circulation or
possible additional energy sources.Comment: 11 pages, 1 figure, published in Natur
Experimental study of acoustic displays of flight parameters in a simulated aerospace vehicle
Evaluating acoustic displays of target location in target detection and of flight parameters in simulated aerospace vehicle
Shock Breakout in Core-Collapse Supernovae and its Neutrino Signature
(Abridged) We present results from dynamical models of core-collapse
supernovae in one spatial dimension, employing a newly-developed Boltzmann
neutrino radiation transport algorithm, coupled to Lagrangean hydrodynamics and
a consistent high-density nuclear equation of state. We focus on shock breakout
and its neutrino signature and follow the dynamical evolution of the cores of
11 M_sun, 15 M_sun, and 20 M_sun progenitors through collapse and the first 250
milliseconds after bounce. We examine the effects on the emergent neutrino
spectra, light curves, and mix of species of artificial opacity changes, the
number of energy groups, the weak magnetism/recoil corrections, nucleon-nucleon
bremsstrahlung, neutrino-electron scattering, and the compressibility of
nuclear matter. Furthermore, we present the first high-resolution look at the
angular distribution of the neutrino radiation field both in the
semi-transparent regime and at large radii and explore the accuracy with which
our tangent-ray method tracks the free propagation of a pulse of radiation in a
near vacuum. Finally, we fold the emergent neutrino spectra with the
efficiencies and detection processes for a selection of modern underground
neutrino observatories and argue that the prompt electron-neutrino breakout
burst from the next galactic supernova is in principle observable and usefully
diagnostic of fundamental collapse/supernova behavior. Though we are not in
this study focusing on the supernova mechanism per se, our simulations support
the theoretical conclusion (already reached by others) that spherical (1D)
supernovae do not explode when good physics and transport methods are employed.Comment: 16 emulateapj pages, plus 24 postscript figures, accepted to The
Astrophysical Journal; text revised; neutrino oscillation section expanded;
Fig. 22 correcte
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