1,223 research outputs found
Integrated mass transportation system study/definition/implementation program definition
Specific actions needed to plan and effect transportation system improvements are identified within the constraints of limited financial, energy and land use resources, and diverse community requirements. A specific program is described which would develop the necessary generalized methodology for devising improved transportation systems and evaluate them against specific criteria for intermodal and intramodal optimization. A consistent, generalized method is provided for study and evaluation of transportation system improvements
An implicit method for radiative transfer with the diffusion approximation in SPH
An implicit method for radiative transfer in SPH is described. The diffusion
approximation is used, and the hydrodynamic calculations are performed by a
fully three--dimensional SPH code. Instead of the energy equation of state for
an ideal gas, various energy states and the dissociation of hydrogen molecules
are considered in the energy calculation for a more realistic temperature and
pressure determination. In order to test the implicit code, we have performed
non--isothermal collapse simulations of a centrally condensed cloud, and have
compared our results with those of finite difference calculations performed by
MB93. The results produced by the two completely different numerical methods
agree well with each other.Comment: 25 pages, 9 figure
Star Formation with Adaptive Mesh Refinement Radiation Hydrodynamics
I provide a pedagogic review of adaptive mesh refinement (AMR) radiation
hydrodynamics (RHD) methods and codes used in simulations of star formation, at
a level suitable for researchers who are not computational experts. I begin
with a brief overview of the types of RHD processes that are most important to
star formation, and then I formally introduce the equations of RHD and the
approximations one uses to render them computationally tractable. I discuss
strategies for solving these approximate equations on adaptive grids, with
particular emphasis on identifying the main advantages and disadvantages of
various approximations and numerical approaches. Finally, I conclude by
discussing areas ripe for improvement.Comment: 8 pages, to appear in the Proceedings of IAU Symposium 270:
Computational Star Formatio
Apollo 7 retrofire and reentry of service propulsion module. Further study of Intelsat 2 F-2 apogee burn
Photography of Apollo 7 retrofire and service propulsion module reentry and apogee burn of Intelsat 2 F-2 satellit
The role of accretion disks in the formation of massive stars
We present radiation hydrodynamics simulations of the collapse of massive
pre-stellar cores. We treat frequency dependent radiative feedback from stellar
evolution and accretion luminosity at a numerical resolution down to 1.27 AU.
In the 2D approximation of axially symmetric simulations, it is possible for
the first time to simulate the whole accretion phase of several 10^5 yr for the
forming massive star and to perform a comprehensive scan of the parameter
space. Our simulation series show evidently the necessity to incorporate the
dust sublimation front to preserve the high shielding property of massive
accretion disks. Our disk accretion models show a persistent high anisotropy of
the corresponding thermal radiation field, yielding to the growth of the
highest-mass stars ever formed in multi-dimensional radiation hydrodynamics
simulations. Non-axially symmetric effects are not necessary to sustain
accretion. The radiation pressure launches a stable bipolar outflow, which
grows in angle with time as presumed from observations. For an initial mass of
the pre-stellar host core of 60, 120, 240, and 480 Msol the masses of the final
stars formed in our simulations add up to 28.2, 56.5, 92.6, and at least 137.2
Msol respectively.Comment: 4 pages, 2 figures, Computational Star Formation Proceedings IAU
Symposium No. 270, 2010, Ed.: J. Alves, B. Elmegreen, J. Girart & V. Trimbl
Learning to facilitate arts-in-health programmes: a case study of musicians facilitating creative interventions for mothers with symptoms of postnatal depression
There is growing research documenting the effects of arts-in-health interventions on diverse participant groups. However, the impact of interventions on facilitators remains largely lacking. Drawing on a case study project, this article reports on a qualitative study to understand the practices, challenges, enablers and impacts for musicians of facilitating creative interventions for women with symptoms of postnatal depression. Thematic analysis revealed that the musicians used specific practices to successfully facilitate their activities, relying on a balance of forward-planning with the need to retain flexibility and provide women with autonomy and opportunities for social bonding. Key challenges included coping with the emotional impact of the project as well as facilitating different types of creative activities, while a strong sense of team and the structure of the interventions supported delivery. Finally, the project enabled the development of both generic and context-specific creative facilitation skills, and also contributed to the facilitatorsâ wellbeing. The logistical, educational and support implications for other practitioners seeking to establish such interventions are considered within the context of arts-in-health and musiciansâ education
When all solutions of xⲠ= ââ qi(t) x(t â Ti(t)) oscillate
AbstractIn this paper the long-term behavior of solutions to the equation in the title are examined, where qi(t) and Ti(t) are positive. In particular, it is shown that if lim inft â â âi = 1n Ti(t) qi(t) > 1/e, all solutions oscillate about 0 infinitely often
How group singing facilitates recovery from the symptoms of postnatal depression: a comparative qualitative study
Background: Previous research has demonstrated that making music can enhance positive emotions as well as support positive psychological functioning. However, studies tend to be limited by lack of comparison with other psychosocial interventions. This study builds on a three-arm randomised controlled trial (RCT) that demonstrated that group singing for mothers and babies, but not group creative play, can lead to faster recovery from moderate-severe symptoms of postnatal depression than usual care. The aim was to elucidate the mechanisms of the group singing intervention in order to account for its recovery properties.
Methods: Qualitative research was conducted with 54 mothers who had experienced symptoms of postnatal depression. Mothers completed a 10-week programme of either group singing or group creative play as part of the wider RCT study. Data were collected via a series of 10 semi-structured focus groups conducted at the end of each 10-week programme. These were designed to elicit subjective and constructed experiences of the singing and play interventions and were analysed inductively for emergent themes.
Results: Five distinctive features of the group singing emerged: (i) providing an authentic, social and multicultural creative experience, (ii) ability to calm babies; (iii) providing immersive âme timeâ for mothers; (iv) facilitating a sense of achievement and identity; (v) enhancing mother-infant bond.
Conclusions: Community group singing interventions may reduce symptoms of postnatal depression through facilitating a functional emotional response rooted in the needs of new motherhood. These features are of relevance to others seeking to implement creative interventions for maternal mental health.
Trial registration: NCT02526407. Registered 18 August 2015
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