13,140 research outputs found
A pitfall of piecewise-polytropic equation of state inference
The only messenger radiation in the Universe which one can use to
statistically probe the Equation of State (EOS) of cold dense matter is that
originating from the near-field vicinities of compact stars. Constraining
gravitational masses and equatorial radii of rotating compact stars is a major
goal for current and future telescope missions, with a primary purpose of
constraining the EOS. From a Bayesian perspective it is necessary to carefully
discuss prior definition; in this context a complicating issue is that in
practice there exist pathologies in the general relativistic mapping between
spaces of local (interior source matter) and global (exterior spacetime)
parameters. In a companion paper, these issues were raised on a theoretical
basis. In this study we reproduce a probability transformation procedure from
the literature in order to map a joint posterior distribution of Schwarzschild
gravitational masses and radii into a joint posterior distribution of EOS
parameters. We demonstrate computationally that EOS parameter inferences are
sensitive to the choice to define a prior on a joint space of these masses and
radii, instead of on a joint space interior source matter parameters. We focus
on the piecewise-polytropic EOS model, which is currently standard in the field
of astrophysical dense matter study. We discuss the implications of this issue
for the field.Comment: 16 pages, 9 figures. Accepted for publication in MNRA
Narratives of therapeutic art-making in the context of marital breakdown: Older women reflect on a significant mid-life experience
This paper explores the narratives of three women aged 65-72 years. They reflected on an episode of therapeutic art-making in midlife, which addressed depression associated with marital crisis and breakdown. The narrative analysis focused upon on the ways in which participants narrated the events leading up to their participation in therapeutic art-making; the aspects of therapeutic art-making that continued to be given significance; the characters given primacy in the stories they told about their journey through therapy and marital breakdown; meanings, symbolic and otherwise, that participants ascribed to their artwork made during this turning point in their lives; and aspects of the narratives that conveyed present-day identities and artistic endeavors. The narratives revealed the complexity of the journey through marital breakdown and depression into health, and showed that therapeutic art-making could best be understood, not as a stand-alone experience, but as given meaning within the context of wider personal and social resources. Participants looked back on therapeutic art-making that occurred two decades earlier and still described this as a significant turning point in their personal development. Art as an adjunct to counselling/therapy was not only symbolically self-expressive but provided opportunity for decision-making, agency and a reformulated self-image
The Non-thermal Radio Jet Toward the NGC 2264 Star Formation Region
We report sensitive VLA 3.6 cm radio observations toward the head of the Cone
nebula in NGC 2264, made in 2006. The purpose of these observations was to
study a non-thermal radio jet recently discovered, that appears to emanate from
the head of the Cone nebula. The jet is highly polarized, with well-defined
knots, and one-sided. The comparison of our images with 1995 archive data
indicates no evidence of proper motions nor polarization changes. We find
reliable flux density variations in only one knot, which we tentatively
identify as the core of a quasar or radio galaxy. An extragalactic location
seems to be the best explanation for this jet.Comment: 12 pages, 5 figure
Application of multidisciplinary optimization methods to the design of a supersonic transport
An optimization design method is discussed. This method is based on integrating existing disciplinary analysis and sensitivity analysis techniques by means of generalized sensitivity equations. A generic design system implementing this method is described. The system is being used to design the configuration and internal structure of a supersonic transport wing for optimum performance. This problem combines the disciplines of linear aerodynamics, structures, and performance. Initial results which include the disciplines of aerodynamics and structures in a conventional minimum weight design under static aeroelastic constraints are presented
Comparison of the electron density measurements using Thomson scattering and emission spectroscopy for laser induced breakdown in one atmosphere of helium
Flow in a slowly-tapering channel with oscillating walls
The flow of a fluid in a channel with walls inclined at an angle to each other is investigated at arbitrary Reynolds number. The flow is driven by an oscillatory motion of the wall incorporating a time-periodic displacement perpendicular to the channel centreline. The gap between the walls varies linearly with distance along the channel and is a prescribed periodic function of time. An approximate solution is constructed assuming that the angle of inclination of the walls is small. At leading order the flow corresponds to that in a channel with parallel, vertically oscillating walls examined by Hall and Papageorgiou \cite{HP}. A careful study of the governing partial differential system for the first order approximation controlling the tapering flow due to the wall inclination is conducted. It is found that as the Reynolds number is increased from zero the tapering flow loses symmetry and undergoes exponential growth in time. The loss of symmetry occurs at a lower Reynolds number than the symmetry-breaking for the parallel-wall flow. A window of asymmetric, time-periodic solutions is found at higher Reynolds number, and these are reached via a quasiperiodic transient from a given set of initial conditions. Beyond this window stability is again lost to exponentially growing solutions as the Reynolds number is increased
Jobseekers Regime and Flexible New Deal, the Six Month Offer and Support for the Newly Unemployed evaluations: An early process study
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The Whole Heliosphere Interval in the Context of a Long and Structured Solar Minimum: An Overview from Sun to Earth
Throughout months of extremely low solar activity during the recent extended solar-cycle minimum, structural evolution continued to be observed from the Sun through the solar wind and to the Earth. In 2008, the presence of long-lived and large low-latitude coronal holes meant that geospace was periodically impacted by high-speed streams, even though solar irradiance, activity, and interplanetary magnetic fields had reached levels as low as, or lower than, observed in past minima. This time period, which includes the first Whole Heliosphere Interval (WHI 1: Carrington Rotation (CR) 2068), illustrates the effects of fast solar-wind streams on the Earth in an otherwise quiet heliosphere. By the end of 2008, sunspots and solar irradiance had reached their lowest levels for this minimum (e.g., WHI 2: CR 2078), and continued solar magnetic-flux evolution had led to a flattening of the heliospheric current sheet and the decay of the low-latitude coronal holes and associated Earth-intersecting high-speed solar-wind streams. As the new solar cycle slowly began, solar-wind and geospace observables stayed low or continued to decline, reaching very low levels by June – July 2009. At this point (e.g., WHI 3: CR 2085) the Sun–Earth system, taken as a whole, was at its quietest. In this article we present an overview of observations that span the period 2008 – 2009, with highlighted discussion of CRs 2068, 2078, and 2085. We show side-by-side observables from the Sun’s interior through its surface and atmosphere, through the solar wind and heliosphere and to the Earth’s space environment and upper atmosphere, and reference detailed studies of these various regimes within this topical issue and elsewhere
International Olympic Committee Consensus Statement: Molecular Basis of Connective Tissue and Muscle Injuries in Sport
Tendon and ligament injures cause significant loss of performance in sport and decreased functional capacity in the workplace. Many of these injures remain difficult to treat, and many individuals have long-term pain and discomfort. Animal studies of growth factor and cell-based therapies have shown promising results, but these treatments also can be misused to enhance athletic performance. The International Olympic Committee (IOC) now has high-level scientific advisors who can advise the IOC as to the use and abuse of these technologies
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