990 research outputs found
Ulysses
The DSN (Deep Space Network) mission support requirements for Ulysses are summarized. The primary goal of the Ulysses mission is to explore the Sun, its environment, and possible links between solar variability and terrestrial weather and climate. The Ulysses spacecraft will be injected into an interplanetary orbit toward Jupiter after which the spacecraft travels in a heliocentric, out-of-ecliptic orbit with high heliographic inclination. The Ulysses mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility
Songwriting and Transformation: The Subjective Experience of Sharing Self Through Song
This qualitative heuristic study explored the subjective experience of transformation resulting from the practice of songwriting in nonclinical populations, through semistructured interviews with 12 songwriters, 6 men and 6 women, aged 35-69. Thematic content analysis yielded 6 top-level themes: Connecting, Communicating, Wellbeing, Affirmation, Personal Growth, and Making A Difference. Subthemes of Connecting reflect a wide variety of transpersonal experiences. The Communicating subthemes capture ways in which songwriting afforded participants a language superior to speech for Expressing Feelings, Sharing Self, and Sending A Message. Participants reported Personal Growth, expressed through subthemes Processing Experience (making meaning of painful material) and Empowerment. Learning explicitly that one of their songs had had a significant impact on a listener was the mostly strongly articulated transformative experience for participants, described in Making A Difference. The findings support models of transformation in the expressive arts literature; through transpersonal encounters in liminality, both songwriter and listeners are transformed
Linseed growing in the Ord River valley
Experimental work with linseed at the Kimberley Research Station began in 1952 and has been intensified in the last four years.
Fertiliser requirements and methods of land preparation, sowing, irrigation and weed control have been established.
Suitable varieties have been selected. Farm-scale crops have been grown in the area and, although cotton is very much more remunerative as an establishment crop, it is expected that linseed will ultimately have a place in the Ord irrigation scheme
Pre-Existing Superbubbles as the Sites of Gamma-Ray Bursts
According to recent models, gamma-ray bursts apparently explode in a wide
variety of ambient densities ranging from ~ 10^{-3} to 30 cm^{-3}. The lowest
density environments seem, at first sight, to be incompatible with bursts in or
near molecular clouds or with dense stellar winds and hence with the
association of gamma-ray bursts with massive stars. We argue that low ambient
density regions naturally exist in areas of active star formation as the
interiors of superbubbles. The evolution of the interior bubble density as a
function of time for different assumptions about the evaporative or
hydrodynamical mass loading of the bubble interior is discussed. We present a
number of reasons why there should exist a large range of inferred afterglow
ambient densities whether gamma-ray bursts arise in massive stars or some
version of compact star coalescence. We predict that many gamma-ray bursts will
be identified with X-ray bright regions of galaxies, corresponding to
superbubbles, rather than with blue localized regions of star formation.
Massive star progenitors are expected to have their own circumstellar winds.
The lack of evidence for individual stellar winds associated with the
progenitor stars for the cases with afterglows in especially low density
environments may imply low wind densities and hence low mass loss rates
combined with high velocities. If gamma-ray bursts are associated with massive
stars, this combination might be expected for compact progenitors with
atmospheres dominated by carbon, oxygen or heavier elements, that is,
progenitors resembling Type Ic supernovae.Comment: 14 pages, no figures, submitted to The Astrophysical Journa
Kimberley Research Station progress report, 1964 : oil crops
INVESTIGATIONS on the adaptation of a range of oil crops to the Ord River environment have been in progress since the early years of the Station
Extension of nano-confined DNA: quantitative comparison between experiment and theory
The extension of DNA confined to nanochannels has been studied intensively
and in detail. Yet quantitative comparisons between experiments and model
calculations are difficult because most theoretical predictions involve
undetermined prefactors, and because the model parameters (contour length, Kuhn
length, effective width) are difficult to compute reliably, leading to
substantial uncertainties. Here we use a recent asymptotically exact theory for
the DNA extension in the "extended de Gennes regime" that allows us to compare
experimental results with theory. For this purpose we performed new
experiments, measuring the mean DNA extension and its standard deviation while
varying the channel geometry, dye intercalation ratio, and ionic buffer
strength. The experimental results agree very well with theory at high ionic
strengths, indicating that the model parameters are reliable. At low ionic
strengths the agreement is less good. We discuss possible reasons. Our approach
allows, in principle, to measure the Kuhn length and effective width of a
single DNA molecule and more generally of semiflexible polymers in solution.Comment: Revised version, 6 pages, 2 figures, 1 table, supplementary materia
On the properties of fractal cloud complexes
We study the physical properties derived from interstellar cloud complexes
having a fractal structure. We first generate fractal clouds with a given
fractal dimension and associate each clump with a maximum in the resulting
density field. Then, we discuss the effect that different criteria for clump
selection has on the derived global properties. We calculate the masses, sizes
and average densities of the clumps as a function of the fractal dimension
(D_f) and the fraction of the total mass in the form of clumps (epsilon). In
general, clump mass does not fulfill a simple power law with size of the type
M_cl ~ (R_cl)**(gamma), instead the power changes, from gamma ~ 3 at small
sizes to gamma<3 at larger sizes. The number of clumps per logarithmic mass
interval can be fitted to a power law N_cl ~ (M_cl)**(-alpha_M) in the range of
relatively large masses, and the corresponding size distribution is N_cl ~
(R_cl)**(-alpha_R) at large sizes. When all the mass is forming clumps
(epsilon=1) we obtain that as D_f increases from 2 to 3 alpha_M increases from
~0.3 to ~0.6 and alpha_R increases from ~1.0 to ~2.1. Comparison with
observations suggests that D_f ~ 2.6 is roughly consistent with the average
properties of the ISM. On the other hand, as the fraction of mass in clumps
decreases (epsilon<1) alpha_M increases and alpha_R decreases. When only ~10%
of the complex mass is in the form of dense clumps we obtain alpha_M ~ 1.2 for
D_f=2.6 (not very different from the Salpeter value 1.35), suggesting this a
likely link between the stellar initial mass function and the internal
structure of molecular cloud complexes.Comment: 32 pages, 13 figures, 1 table. Accepted for publication in Ap
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