V2051 Ophiuchi after superoutburst : out-of-plane material and the superhump light source

Aims. We performed a detailed spectroscopic analysis of the dwarf nova V2051 Oph at the end of its 1999 superoutburst. We studied and interpreted the simultaneous behaviour of various emission lines. Methods. We obtained high-resolution echelle spectroscopic data at ESO’s NTT with EMMI, covering the spectral range of 4000–7500 Å. The analysis was performed using standard IRAF tools. The indirect imaging technique of Doppler tomography was applied, in order to map the accretion disc and distinguish between the different emission sources. Results. The spectra are characterised by strong Balmer emission, together with lines of He i and the iron triplet Fe ii 42. All lines are double-peaked, but the blue-to-red peak strength and central absorption depth vary. The primary’s velocity was found to be 84.9 kms−1. The spectrograms of the emission lines reveal the prograde rotation of a disc-like emitting region and, for the Balmer and He i lines, an enhancement of the red-wing during eclipse indicates a bright spot origin. The modulation of the double-peak separation shows a highly asymmetric disc with non-uniform emissivity. This is confirmed by the Doppler maps, which apart from the disc and bright spot emission also indicate an additional region of enhanced emission in the 4th quadrant (+Vx, −Vy), which we associate with the superhump light source. Given the behaviour of the iron triplet and its distinct differences from the rest of the lines, we attribute its existence to an extended gas region above the disc. Its origin can be explained through the fluorescence mechanism

CNS Technology Website Administrative Guide (Version 1.0)

Air Force Office of Scientific Research (F49620-01-1-0397); National Science Foundation (SBE-0354378); Office of Naval Research (N00014-01-1-0624)

OPRM: Challenges to Including Open Peer Review in Open Access Repositories

The peer review system is the norm for many publications. It involves an editor and several experts in the field providing comments for a submitted article. The reviewer remains anonymous to the author, with only the editor knowing the reviewer´s identity. This model is now being challenged and open peer review (OPR) models are viewed as the new frontier of the review process. OPR is a term that encompasses diverse variations in the traditional review process. Examples of this are modifications in the way in which authors and reviewers are aware of each other’s identity (open identities), the visibility of the reviews carried out (open reviews) or the opening up of the review to the academic community (open participation). We present the project for the implementation of an Open Peer Review Module in two major Spanish repositories, DIGITAL.CSIC and e-IEO, together with some promising initial results and challenges in the take-up process. The OPR module, designed for integration with DSpace repositories, enables any scholar to provide a qualitative and quantitative evaluation of any research object hosted in these repositories

An in-depth study of the pre-polar candidate WX Leonis Minoris

Optical photometry, spectroscopy, and XMM-Newton ultraviolet and X-ray observations with full phase coverage are used for an in-depth study of WXLMi, a system formerly termed a low-accretion rate polar. We find a constant low-mass accretion rate, ˙M ∼ 1.5 × 10−13 M yr−1, a peculiar accretion geometry with one spot not accessible via Roche-lobe overflow, a low temperature of the white dwarf, Teff < 8000 K, and the secondary very likely Roche-lobe underfilling. All this lends further support to the changed view on WXLMi and related systems as detached binaries, i.e. magnetic post-common envelope binaries without significant Rochelobe overflow in the past. The transfer rate determined here is compatible with accretion from a stellar wind. We use cyclotron spectroscopy to determine the accretion geometry and to constrain the plasma temperatures. Both cyclotron spectroscopy and X-ray plasma diagnostics reveal low plasma temperatures below 3 keV on both accretion spots. For the low-m˙ , high-B plasma at the accretion spots in WXLMi, cyclotron cooling dominates thermal plasma radiation in the optical. Optical spectroscopy and X-ray timing reveal atmospheric, chromospheric, and coronal activity at the saturation level on the dM4.5 secondary star

PicoLibre : a free collaborative platform to improve students'skills in software engineering

International audienceThe work described in this paper consists in the development of a pedagogical collaborative platform to improve the know-how of our students in software engineering and collaborative work. Its use in a free software context leads to greater commitment of the students and better reusability of their work

How can contributors to open-source communities be trusted? On the assumption, inference, and substitution of trust

Open-source communities that focus on content rely squarely on the contributions of invisible strangers in cyberspace. How do such communities handle the problem of trusting that strangers have good intentions and adequate competence? This question is explored in relation to communities in which such trust is a vital issue: peer production of software (FreeBSD and Mozilla in particular) and encyclopaedia entries (Wikipedia in particular). In the context of open-source software, it is argued that trust was inferred from an underlying 'hacker ethic', which already existed. The Wikipedian project, by contrast, had to create an appropriate ethic along the way. In the interim, the assumption simply had to be that potential contributors were trustworthy; they were granted 'substantial trust'. Subsequently, projects from both communities introduced rules and regulations which partly substituted for the need to perceive contributors as trustworthy. They faced a design choice in the continuum between a high-discretion design (granting a large amount of trust to contributors) and a low-discretion design (leaving only a small amount of trust to contributors). It is found that open-source designs for software and encyclopaedias are likely to converge in the future towards a mid-level of discretion. In such a design the anonymous user is no longer invested with unquestioning trust

Harvesting for disseminating, open archives and role of academic libraries

The Scholarly communication system is in a critical stage, due to a number of factors.The Open Access movement is perhaps the most interesting response that the scientific community has tried to give to this problem. The paper examines strengths and weaknesses of the Open Access strategy in general and, more specifically, of the Open Archives Initiative, discussing experiences, criticisms and barriers. All authors that have faced the problems of implementing an OAI compliant e-print server agree that technical and practical problems are not the most difficult to overcome and that the real problem is the change in cultural attitude required. In this scenario the university library is possibly the standard bearer for the advent and implementation of e-prints archives and Open Archives services. To ensure the successful implementation of this service the Library has a number of distinct roles to play

Assessing architectural evolution: A case study

This is the post-print version of the Article. The official published can be accessed from the link below - Copyright @ 2011 SpringerThis paper proposes to use a historical perspective on generic laws, principles, and guidelines, like Lehman’s software evolution laws and Martin’s design principles, in order to achieve a multi-faceted process and structural assessment of a system’s architectural evolution. We present a simple structural model with associated historical metrics and visualizations that could form part of an architect’s dashboard. We perform such an assessment for the Eclipse SDK, as a case study of a large, complex, and long-lived system for which sustained effective architectural evolution is paramount. The twofold aim of checking generic principles on a well-know system is, on the one hand, to see whether there are certain lessons that could be learned for best practice of architectural evolution, and on the other hand to get more insights about the applicability of such principles. We find that while the Eclipse SDK does follow several of the laws and principles, there are some deviations, and we discuss areas of architectural improvement and limitations of the assessment approach

ID3.24 - Updated design for release 6.0 of the TENCompetence software

Vogten, H., Martens, H., Heyenrath, S., Lemmers, R., Alberts, J., Finders, A., & Schaeps, L. (2009). ID3.24 - Updated design for release 6.0 of the TENCompetence software. TENCompetence.Describes the software architecture of release 6.0 of the PCM, the final release of the project, to developers that need to use, extend or change the PCM server. The views from the 4+1 approach by Kruchten are used to describe the software architecture.The work on this publication has been sponsored by the TENCompetence Integrated Project that is funded by the European Commission's 6th Framework Programme, priority IST/Technology Enhanced Learning. Contract 027087 [http://www.tencompetence.org