1,911 research outputs found
A balloon-borne 1 meter telescope for far-infrared astronomy
The flight of a balloon-borne one-meter telescope for infrared astronomy in the wavelength interval of 40 to 240 microns is discussed. The gyro-stabilized telescope mapped the intensity of the far infrared radiation from NGC 7538, Mars, the Orion Nebula, and W3 with a resolution of one minute and from selected regions of these sources with a resolution of 30 seconds. The infrared detection is described and its capabilities are analyzed. The instrumentation, orientation system, and modes of observation of the telescope are defined
Escuchar a los objetos
This experimental section includes some parts of the performative event “The materiality of transformations: Listening to objects”, which closed the 14th SIEF conference held in Santiago de Compostela in 2019. Barbara Kirshenblatt-Gimblett, Regina Bendix, Dorothy Noyes, Sharon Roseman and Francisco Cruces conversed on stage about the cultural meanings of a selection of personal objects. By unveiling the stories contained in mezuzahs, hair, a serving platter and a shawl, they put the methodological power of the object/story couplet to the test. The benefits of articulating narrativity with materiality; the silent power of things in everyday life; the embedded character of storytelling, and some of its affective, moral and celebratory virtues were highlighted. The final event can be seen at <https://vimeo.com/362078953> from minute 00:52:50 to 01:31:00.Esta sección experimental incluye algunas partes del evento performativo “La materialidad de las transformaciones: escuchar a los objetos”, que clausuró el XIV congreso de SIEF celebrado en Santiago de Compostela en 2019. Barbara Kirshenblatt-Gimblett, Regina Bendix, Dorothy Noyes, Sharon Roseman y Francisco Cruces conversaron sobre los significados culturales de una selección de objetos personales. Al desvelar las historias contenidas en mezuzahs, cabello, una fuente o un chal, se puso a prueba el poder metodológico del par objeto / historia, los beneficios de articular la narratividad con la materialidad y el silencioso poder de las cosas en la vida cotidiana. Se destacó el carácter incorporado de la narración y algunas de sus virtudes afectivas, morales y celebratorias. Este evento performativo se puede ver en <https://vimeo.com/362078953> from minute 00:52:50 to 01:31:00
The Case Against Cold, Dark Chromospheres
Is the solar chromosphere always hot, with relatively small temperature
variations (); or is it cold most of the time, with
temperature fluctuations that reach at the top of the
chromosphere? Or, equivalently: Is the chromosphere heated continually, or only
for a few seconds once every three minutes? Two types of empirical model, one
essentially time independent and always hot, the other highly time dependent
and mostly cold, come to fundamentally different conclusions. This paper
analyzes the time-dependent model of the quiet, nonmagnetic chromosphere by
Carlsson & Stein (1994: CS94) and shows that it predicts deep absorption lines,
none of which is observed; intensity fluctuations in the Lyman continuum that
are much larger than observed; and time-averaged emission that falls far short
of the observed emission. The paper concludes that the solar chromosphere,
while time dependent, is never cold and dark. The same conclusion applies for
stellar chromospheres.
A complete, time-dependent model of the nonmagnetic chromosphere must
describe two phenomena: (1) dynamics, like that modeled by CS94 for
chromospheric bright points but corrected for the geometrical properties of
shocks propagating in an upward-expanding channel; and (2) the energetically
more important general, sustained heating of the chromosphere, as described by
current time-independent empirical models, but modified in the upper
photosphere for the formation of molecular absorption lines of CO in a
dynamical medium. This model is always hot and, except for absorption features
caused by departures from local thermodynamic equilibrium, shows chromospheric
lines only in emission.Comment: 22 pages, 5 figures (in 6 files
Evidence-based planning and costing palliative care services for children : novel multi-method epidemiological and economic exemplar
Background:
Children’s palliative care is a relatively new clinical specialty. Its nature is multi-dimensional and its delivery necessarily multi-professional. Numerous diverse public and not-for-profit organisations typically provide services and support. Because services are not centrally coordinated, they are provided in a manner that is inconsistent and incoherent. Since the first children’s hospice opened in 1982, the epidemiology of life-limiting conditions has changed with more children living longer, and many requiring transfer to adult services. Very little is known about the number of children living within any given geographical locality, costs of care, or experiences of children with ongoing palliative care needs and their families. We integrated evidence, and undertook and used novel methodological epidemiological work to develop the first evidence-based and costed commissioning exemplar.
Methods:
Multi-method epidemiological and economic exemplar from a health and not-for-profit organisation perspective, to estimate numbers of children under 19 years with life-limiting conditions, cost current services, determine child/parent care preferences, and cost choice of end-of-life care at home.
Results:
The exemplar locality (North Wales) had important gaps in service provision and the clinical network. The estimated annual total cost of current children’s palliative care was about £5.5 million; average annual care cost per child was £22,771 using 2007 prevalence estimates and £2,437- £11,045 using new 2012/13 population-based prevalence estimates. Using population-based prevalence, we estimate 2271 children with a life-limiting condition in the general exemplar population and around 501 children per year with ongoing palliative care needs in contact with hospital services. Around 24 children with a wide range of life-limiting conditions require end-of-life care per year. Choice of end-of-life care at home was requested, which is not currently universally available. We estimated a minimum (based on 1 week of end-of-life care) additional cost of £336,000 per year to provide end-of-life support at home. Were end-of-life care to span 4 weeks, the total annual additional costs increases to £536,500 (2010/11 prices).
Conclusions:
Findings make a significant contribution to population-based needs assessment and commissioning methodology in children’s palliative care. Further work is needed to determine with greater precision which children in the total population require access to services and when. Half of children who died 2002-7 did not have conditions that met the globally used children's palliative care condition categories, which need revision in light of findings
HAT-P-5b: A Jupiter-like hot Jupiter Transiting a Bright Star
We report the discovery of a planet transiting a moderately bright (V =
12.00) G star, with an orbital period of 2.788491 +/-0.000025 days. From the
transit light curve we determine that the radius of the planet is Rp = 1.257
+/- 0.053 RJup. HAT-P-5b has a mass of Mp = 1.06 +/- 0.11 MJup, similar to the
average mass of previously-known transiting exoplanets, and a density of rho =
0.66 +/- 0.11 g cm^-3 . We find that the center of transit is Tc =
2,454,241.77663 +/- 0.00022 (HJD), and the total transit duration is 0.1217 +/-
0.0012 days.Comment: 5 pages, submitted to APJ
Dynamics of Magnetic Flux Elements in the Solar Photosphere
The interaction of magnetic fields and convection is investigated in the
context of the coronal heating problem. We study the motions of photospheric
magnetic elements using filtergrams obtained at the Swedish Vacuum Solar
Telescope at La Palma. We use potential-field modeling to extrapolate the
magnetic and velocity fields to larger height. We find that the velocity in the
chromosphere can be locally enhanced at the separatrix surfaces between
neighboring flux tubes. The predicted velocities are several km/s,
significantly larger than those of the photospheric flux tubes, which may have
important implications for coronal heating. sComment: submitted to ApJ, 21 pages, 10 figure
The Quiet-Sun Photosphere and Chromosphere
The overall structure and the fine structure of the solar photosphere outside
active regions are largely understood, except possibly important roles of a
turbulent near-surface dynamo at its bottom, internal gravity waves at its top,
and small-scale vorticity. Classical 1D static radiation-escape modelling has
been replaced by 3D time-dependent MHD simulations that come closer to reality.
The solar chromosphere, in contrast, remains ill-understood although its
pivotal role in coronal mass and energy loading makes it a principal research
area. Its fine structure defines its overall structure, so that hard-to-observe
and hard-to-model small-scale dynamical processes are the key to understanding.
However, both chromospheric observation and chromospheric simulation presently
mature towards the required sophistication. The open-field features seem of
greater interest than the easier-to-see closed-field features.Comment: Accepted for special issue "Astrophysical Processes on the Sun" of
Phil. Trans. Royal Soc. A, ed. C. Parnell. Note: clicking on the year in a
citation opens the corresponding ADS abstract page in the browse
On the link between rotation, chromospheric activity and Li abundance in subgiant stars
The connection rotation-CaII emission flux-lithium abundance is analyzed for
a sample of bona fide subgiant stars, with evolutionary status determined from
HIPPARCOS trigonometric parallax measurements and from the Toulouse-Geneva
code.Comment: 9 pages, 8 figure
Refined parameters of the planet orbiting HD 189733
We report on the BVRI multi-band follow-up photometry of the transiting
extrasolar planet HD 189733b. We revise the transit parameters and find
planetary radius RP = 1.154+/- 0.032RJ and inclination i_P = 85.79+/-0.24deg.
The new density (~ 1g cm-3) is significantly higher than the former estimate (~
0.75g cm-3); this shows that from the current sample of 9 transiting planets,
only HD 209458 (and possibly OGLE-10b) have anomalously large radii and low
densities. We note that due to the proximity of the parent star, HD 189733b
currently has one of the most precise radius determinations among extrasolar
planets. We calculate new ephemerides: P = 2.218573+/-0.000020 days, T0 =
2453629.39420+/-0.00024 (HJD), and estimate the timing offsets of the 11
distinct transits with respect to the predictions of a constant orbital period,
which can be used to reveal the presence of additional planets in the system.Comment: 10 pages, 4 figures, submitted to Ap
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