4,509 research outputs found
How MlBibTeX's Documentation Is Organised
International audienceMlBibTeX's documentation is planned to be multilingual---that is, written in several languages---and to be able to share as many examples as possible. Different people can write translations of the original English documentation in parallel. Besides, we show how the translations of this documentation can be updated if need be. This documentation can be used as a printed text or as an on-line document. The functionalities managing this documentation can be reused by another program. In a first part, we explain in detail what our requirements are. Then we show how they are implemented
Instability of non-Keplerian warped discs
Many accretion discs are thought to be warped. Recent hydrodynamical
simulations show that (i) discs can break into distinct planes when the
amplitude of an imposed warp is sufficiently high and the viscosity
sufficiently low, and that (ii) discs can tear up into discrete rings when an
initially planar disc is subject to a forced precession. Previously, we
investigated the local stability of isolated, Keplerian, warped discs in order
to understand the physics causing an accretion disc to break into distinct
planes, finding that anti-diffusion of the warp amplitude is the underlying
cause. Here, we explore the behaviour of this instability in disc regions where
the rotation profile deviates from Keplerian. We find that at small warp
amplitudes non-Keplerian rotation can stabilize the disc by increasing the
critical warp amplitude for instability, while at large warp amplitudes
non-Keplerian rotation can lead to an increased growth rate for discs that are
unstable. Tidal effects on discs in binary systems are typically weak enough
such that the disc remains close to Keplerian rotation. However, the inner
regions of discs around black holes are strongly affected, with the smallest
radius at which the disc can break into discrete planes being a function of the
black hole spin. We suggest that interpreting observed frequencies in the power
spectra of light curves from accreting compact objects as nodal and apsidal
precession of discrete orbits requires an instability that can break the disc
into discrete rings such as the one explored here.Comment: 12 pages, 8 figures, accepted for publication in MNRA
A Transiting Planet of a Sun-like Star
A planet transits an 11th magnitude, G1V star in the constellation Corona
Borealis. We designate the planet XO-1b, and the star, XO-1, also known as GSC
02041-01657. XO-1 lacks a trigonometric distance; we estimate it to be 200+-20
pc. Of the ten stars currently known to host extrasolar transiting planets, the
star XO-1 is the most similar to the Sun in its physical characteristics: its
radius is 1.0+-0.08 R_Sun, its mass is 1.0+-0.03 M_Sun, V sini < 3 km/s, and
its metallicity [Fe/H] is 0.015+-0.04. The orbital period of the planet XO-1b
is 3.941534+-0.000027 days, one of the longer ones known. The planetary mass is
0.90+-0.07 M_Jupiter, which is marginally larger than that of other transiting
planets with periods between 3 and 4 days. Both the planetary radius and the
inclination are functions of the spectroscopically determined stellar radius.
If the stellar radius is 1.0+-0.08 R_Sun, then the planetary radius is
1.30+-0.11 R_Jupiter and the inclination of the orbit is 87.7+-1.2 degrees. We
have demonstrated a productive international collaboration between professional
and amateur astronomers that was important to distinguishing this planet from
many other similar candidates.Comment: 31 pages, 9 figures, accepted for part 1 of Ap
Research Articles in Simplified HTML: a Web-first format for HTML-based scholarly articles
Purpose. This paper introduces the Research Articles in Simplified HTML (or RASH), which is a Web-first format for writing HTML-based scholarly papers; it is accompanied by the RASH Framework, a set of tools for interacting with RASH-based articles. The paper also presents an evaluation that involved authors and reviewers of RASH articles submitted to the SAVE-SD 2015 and SAVE-SD 2016 workshops.
Design. RASH has been developed aiming to: be easy to learn and use; share scholarly documents (and embedded semantic annotations) through the Web; support its adoption within the existing publishing workflow.
Findings. The evaluation study confirmed that RASH is ready to be adopted in workshops, conferences, and journals and can be quickly learnt by researchers who are familiar with HTML.
Research Limitations. The evaluation study also highlighted some issues in the adoption of RASH, and in general of HTML formats, especially by less technically savvy users. Moreover, additional tools are needed, e.g., for enabling additional conversions from/to existing formats such as OpenXML.
Practical Implications. RASH (and its Framework) is another step towards enabling the definition of formal representations of the meaning of the content of an article, facilitating its automatic discovery, enabling its linking to semantically related articles, providing access to data within the article in actionable form, and allowing integration of data between papers.
Social Implications. RASH addresses the intrinsic needs related to the various users of a scholarly article: researchers (focussing on its content), readers (experiencing new ways for browsing it), citizen scientists (reusing available data formally defined within it through semantic annotations), publishers (using the advantages of new technologies as envisioned by the Semantic Publishing movement).
Value. RASH helps authors to focus on the organisation of their texts, supports them in the task of semantically enriching the content of articles, and leaves all the issues about validation, visualisation, conversion, and semantic data extraction to the various tools developed within its Framework
TEMPO2, a new pulsar timing package. I: Overview
Contemporary pulsar timing experiments have reached a sensitivity level where
systematic errors introduced by existing analysis procedures are limiting the
achievable science. We have developed tempo2, a new pulsar timing package that
contains propagation and other relevant effects implemented at the 1ns level of
precision (a factor of ~100 more precise than previously obtainable). In
contrast with earlier timing packages, tempo2 is compliant with the general
relativistic framework of the IAU 1991 and 2000 resolutions and hence uses the
International Celestial Reference System, Barycentric Coordinate Time and
up-to-date precession, nutation and polar motion models. Tempo2 provides a
generic and extensible set of tools to aid in the analysis and visualisation of
pulsar timing data. We provide an overview of the timing model, its accuracy
and differences relative to earlier work. We also present a new scheme for
predictive use of the timing model that removes existing processing artifacts
by properly modelling the frequency dependence of pulse phase.Comment: Accepted by MNRA
The Enhancement of Teaching Materials for Applied Statistics Courses by Combining Random Number Generation and Portable Document Format Files via LaTeX
E-books, articles and other documents in portable document format (PDF) files are becoming more common, and they can incorporate videos, hyperlinks, and JavaScript. This article focuses on combining random number generation and PDF files in order to enhance the effectiveness of teaching materials. For example, a traditional textbook might have a few problems per chapter, but by utilizing JavaScript and embedding it within a PDF file, it is possible to create practically an unlimited number of problems with solutions. Another possible use of random number generation for an instructor is to create assignments and exams with unique numbers. The article contains two examples for the reader with their associated JavaScript and LaTeX code. Finally, the paper covers, in general, how to use JavaScript, random number generation, and LaTeX for enhancing teaching materials in terms of instruction and assessment
Very Late Thermal Pulses Influenced by Accretion in Planetary Nebulae
We consider the possibility that a mass of ~10^{-5}-10^{-3} Msun flows back
from the dense shell of planetary nebulae and is accreted by the central star
during the planetary nebula phase. This backflowing mass is expected to have a
significant specific angular momentum even in (rare) spherical planetary
nebulae, such that a transient accretion disk might be formed. This mass might
influence the occurrence and properties of a very late thermal pulse (VLTP),
and might even trigger it. For example, the rapidly rotating outer layer, and
the disk if still exist, might lead to axisymmetrical mass ejection by the
VLTP. Unstable burning of accreted hydrogen might result in a mild flash of the
hydrogen shell, also accompanied by axisymmetrical ejection.Comment: Submitted to New Astronom
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