15,282 research outputs found
They (Don't) Care About Education: A Counternarrative on Black Male Students' Responses to Inequitable Schooling
Focus group interviews and systematic content analysis of 304 essays written by black male undergraduates refute the dominant message that black men do not care about education. On the contrary, these students aspire to earn doctoral degrees in education despite acute understanding that the education system is stacked against them. The analysis asks what compels that dedication
Toxicity studies of Coolanol 15 Final report, Jan. - Sep. 1965
Toxicity studies of synthetic fluid coolant for manned spacecraft heat transfer system
Carbon isotope anomaly in the major plant C-1 pool and its global biogeochemical implications
We report that the most abundant C-1 units of terrestrial plants, the methoxyl groups of pectin and lignin, have a unique carbon isotope signature exceptionally depleted in C-13. Plant-derived C-1 volatile organic compounds (VOCs) are also anomalously depleted in C-13 compared with Cn+1 VOCs. The results confirm that the plant methoxyl pool is the predominant source of biospheric C-1 compounds of plant origin such as methanol, chloromethane and bromomethane. Furthermore this pool, comprising ca 2.5% of carbon in plant biomass, could be an important substrate for methanogenesis and thus be envisaged as a possible source of isotopically light methane entering the atmosphere. Our findings have significant implications for the use of carbon isotope ratios in elucidation of global carbon cycling. Moreover methoxyl groups could act as markers for biological activity in organic matter of terrestrial and extraterrestrial origin
The MMT API: A Generic MKM System
The MMT language has been developed as a scalable representation and
interchange language for formal mathematical knowledge. It permits natural
representations of the syntax and semantics of virtually all declarative
languages while making MMT-based MKM services easy to implement. It is
foundationally unconstrained and can be instantiated with specific formal
languages.
The MMT API implements the MMT language along with multiple backends for
persistent storage and frontends for machine and user access. Moreover, it
implements a wide variety of MMT-based knowledge management services. The API
and all services are generic and can be applied to any language represented in
MMT. A plugin interface permits injecting syntactic and semantic idiosyncrasies
of individual formal languages.Comment: Conferences on Intelligent Computer Mathematics (CICM) 2013 The final
publication is available at http://link.springer.com
Propagation of the First Flames in Type Ia Supernovae
We consider the competition of the different physical processes that can
affect the evolution of a flame bubble in a Type Ia supernovae -- burning,
turbulence and buoyancy. Even in the vigorously turbulent conditions of a
convecting white dwarf, thermonuclear burning that begins at a point near the
center (within 100 km) of the star is dominated by the spherical laminar
expansion of the flame, until the burning region reaches kilometers in size.
Consequently flames that ignite in the inner ~20 km promptly burn through the
center, and flame bubbles anywhere must grow quite large--indeed, resolvable by
large-scale simulations of the global system--for significant motion or
deformation occur. As a result, any hot-spot that successfully ignites into a
flame can burn a significant amount of white dwarf material. This potentially
increases the stochastic nature of the explosion compared to a scenario where a
simmering progenitor can have small early hot-spots float harmlessly away.
Further, the size where the laminar flame speed dominates other relevant
velocities sets a characteristic scale for fragmentation of larger flame
structures, as nothing--by definition--can easily break the burning region into
smaller volumes. This makes possible the development of semi-analytic
descriptions of the earliest phase of the propagation of burning in a Type Ia
supernovae, which we present here. Our analysis is supported by fully resolved
numerical simulations of flame bubbles.Comment: 33 pages, 14 figures, accepted for publication in Ap
Far infrared and submillimeter brightness temperatures of the giant planets
The brightness temperatures of Jupiter, Saturn, Uranus, and Neptune in the range 35 to 1000 micron. The effective temperatures derived from the measurements, supplemented by shorter wavelength Voyager data for Jupiter and Saturn, are 126.8 + or - 4.5 K, 93.4 + or - 3.3 K, 58.3 + or - 2.0 K, and 60.3 + or - 2.0 K, respectively. The implications of the measurements for bolometric output and for atmospheric structure and composition are discussed. The temperature spectrum of Jupiter shows a strong peak at approx. 350 microns followed by a deep valley at approx. 450 to 500 microns. Spectra derived from model atmospheres qualitatively reproduced these features but do not fit the data closely
Augmented Reality for the Control Tower: The RETINA Concept
The SESAR (Single European Sky Air Traffic Management Research) Joint Undertaking has recently granted the Resilient Synthetic Vision for Ad- vanced Control Tower Air Navigation Service Provision project within the framework of the H2020 research on High Performing Airport Operations. Here- after, we describe the project motivations, the objectives, the proposed method- ology and the expected impacts, i.e. the consequences of using virtual/augmented reality technologies in the control tower
Dependent Types for Pragmatics
This paper proposes the use of dependent types for pragmatic phenomena such
as pronoun binding and presupposition resolution as a type-theoretic
alternative to formalisms such as Discourse Representation Theory and Dynamic
Semantics.Comment: This version updates the paper for publication in LEU
Imaging the dynamical atmosphere of the red supergiant Betelgeuse in the CO first overtone lines with VLTI/AMBER
We present the first 1-D aperture synthesis imaging of the red supergiant
Betelgeuse in the individual CO first overtone lines with VLTI/AMBER. The
reconstructed 1-D projection images reveal that the star appears differently in
the blue wing, line center, and red wing of the individual CO lines. The 1-D
projection images in the blue wing and line center show a pronounced,
asymmetrically extended component up to ~1.3 stellar radii, while those in the
red wing do not show such a component. The observed 1-D projection images in
the lines can be reasonably explained by a model in which the CO gas within a
region more than half as large as the stellar size is moving slightly outward
with 0--5 km s^-1, while the gas in the remaining region is infalling fast with
20--30 km s^-1. A comparison between the CO line AMBER data taken in 2008 and
2009 shows a significant time variation in the dynamics of the CO line-forming
region in the photosphere and the outer atmosphere. In contrast to the line
data, the reconstructed 1-D projection images in the continuum show only a
slight deviation from a uniform disk or limb-darkened disk. We derive a
uniform-disk diameter of 42.05 +/- 0.05 mas and a power-law-type limb-darkened
disk diameter of 42.49 +/- 0.06 mas and a limb-darkening parameter of (9.7 +/-
0.5) x 10^{-2}. This latter angular diameter leads to an effective temperature
of 3690 +/- 54 K for the continuum-forming layer. These diameters confirm that
the near-IR size of Betelgeuse was nearly constant over the last 18 years, in
marked contrast to the recently reported noticeable decrease in the mid-IR
size. The continuum data taken in 2008 and 2009 reveal no or only marginal time
variations, much smaller than the maximum variation predicted by the current
3-D convection simulations.Comment: 21 pages, 12 figures, accepted for publication in Astronomy and
Astrophysic
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Multi-stakeholder perspectives of locally commissioned enhanced optometric services
OBJECTIVES: To explore views of all stakeholders (patients, optometrists, general practitioners (GPs), commissioners and ophthalmologists) regarding the operation of community-based enhanced optometric services.
DESIGN: Qualitative study using mixed methods (patient satisfaction surveys, semi-structured telephone interviews and optometrist focus groups).
SETTING: A minor eye conditions scheme (MECS) and glaucoma referral refinement scheme (GRRS) provided by accredited community optometrists.
PARTICIPANTS: 189 patients, 25 community optometrists, 4 glaucoma specialist hospital optometrists (GRRS), 5 ophthalmologists, 6 GPs (MECS), 4 commissioners.
RESULTS: Overall, 99% (GRRS) and 100% (MECS) patients were satisfied with their optometrists' examination. The vast majority rated the following as 'very good'; examination duration, optometrists' listening skills, explanations of tests and management, patient involvement in decision-making, treating the patient with care and concern. 99% of MECS patients would recommend the service. Manchester optometrists were enthusiastic about GRRS, feeling fortunate to practise in a 'pro-optometry' area. No major negatives were reported, although both schemes were limited to patients resident within certain postcode areas, and some inappropriate GP referrals occurred (MECS). Communication with hospitals was praised in GRRS but was variable, depending on hospital (MECS). Training for both schemes was valuable and appropriate but should be ongoing. MECS GPs were very supportive, reporting the scheme would reduce secondary care referral numbers, although some MECS patients were referred back to GPs for medication. Ophthalmologists (MECS and GRRS) expressed very positive views and widely acknowledged that these new care pathways would reduce unnecessary referrals and shorten patient waiting times. Commissioners felt both schemes met or exceeded expectations in terms of quality of care, allowing patients to be seen quicker and more efficiently.
CONCLUSIONS: Locally commissioned schemes can be a positive experience for all involved. With appropriate training, clear referral pathways and good communication, community optometrists can offer high-quality services that are highly acceptable to patients, health professionals and commissioners
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