The spectroscopic orbits and the geometrical configuration of the symbiotic binary AR Pavonis

We analyze optical and near infrared spectra of intermediate and high resolution of the eclipsing symbiotic system AR Pavonis. We have obtained the radial velocity curves for the red and the hot component from the M-giant absorption lines and from the wings of Halpha, H and He II4686 emission profiles, respectively. From the orbital elements we have derived the masses, Mgiant=2.5 and Mhot =1.0 solar masses, for the red giant and the hot component, respectively. We also present and discuss radial velocity patterns in the blue cF absorption spectrum as well as various emission lines. In particular, we confirm that the blue absorption lines are associated with the hot component. The radial velocity curve of the blue absorption system, however, does not track the hot companion's orbital motion in a straightforward way, and its departures from an expected circular orbit are particularly strong when the hot component is active. We suggest that the cF-type absorption system is formed in material streaming from the giant presumably in a region where the stream encounters an accretion disk or an extended envelope around the hot component. The broad emission wings originate from the inner accretion disk or the envelope around the hot star.We also suggest that the central absorption in H profiles is formed in a neutral portion of the cool giant's wind which is strongly concentrated towards the orbital plane. The nebula in AR Pav seems to be bounded by significant amount of neutral material in the orbital plane. The forbidden emission lines are probably formed in low density ionized regions extended in polar directions and/or the wind-wind interaction zone.Comment: 12 pages, 5 figures, accepted by A&

Mobility of Bloch Walls via the Collective Coordinate Method

We have studied the problem of the dissipative motion of Bloch walls considering a totally anisotropic one dimensional spin chain in the presence of a magnetic field. Using the so-called "collective coordinate method" we construct an effective Hamiltonian for the Bloch wall coupled to the magnetic excitations of the system. It allows us to analyze the Brownian motion of the wall in terms of the reflection coefficient of the effective potential felt by the excitations due to the existence of the wall. We find that for finite values of the external field the wall mobility is also finite. The spectrum of the potential at large fields is investigated and the dependence of the damping constant on temperature is evaluated. As a result we find the temperature and magnetic field dependence of the wall mobility.Comment: 20 pages, 5 figure

Dark matter directional detection with MIMAC

MiMac is a project of micro-TPC matrix of gaseous (He3, CF4) chambers for direct detection of non-baryonic dark matter. Measurement of both track and ionization energy will allow the electron-recoil discrimination, while access to the directionnality of the tracks will open a unique way to distinguish a geniune WIMP signal from any background. First reconstructed tracks of 5.9 keV electrons are presented as a proof of concept.Comment: 4 pages, proc. of the 44th Rencontres De Moriond: Electroweak Interactions And Unified Theories, 7-14 Mar 2009, La Thuile, Ital

Stakeholder perspectives on the development of a virtual clinic for diabetes care : qualitative study

Background: The development of the Internet has created new opportunities for health care provision, including its use as a tool to aid the self-management of chronic conditions. We studied stakeholder reactions to an Internet-based “virtual clinic,” which would allow people with diabetes to communicate with their health care providers, find information about their condition, and share information and support with other users. Objective: The aim of the study was to present the results of a detailed consultation with a variety of stakeholder groups in order to identify what they regard as the desirable, important, and feasible characteristics of an Internet-based intervention to aid diabetes self-management. Methods: Three focus groups were conducted with 12 people with type 1 diabetes who used insulin pumps. Participants were recruited through a local diabetes clinic. One-on-one interviews were conducted with 5 health care professionals from the same clinic (2 doctors, 2 nurses, 1 dietitian) and with 1 representative of an insulin pump company. We gathered patient consensus via email on the important and useful features of Internet-based systems used for other chronic conditions (asthma, epilepsy, myalgic encephalopathy, mental health problems). A workshop to gather expert consensus on the use of information technology to improve the care of young people with diabetes was organized. Results: Stakeholder groups identified the following important characteristics of an Internet-based virtual clinic: being grounded on personal needs rather than only providing general information; having the facility to communicate with, and learn from, peers; providing information on the latest developments and news in diabetes; being quick and easy to use. This paper discusses these characteristics in light of a review of the relevant literature. The development of a virtual clinic for diabetes that embodies these principles, and that is based on self-efficacy theory, is described. Conclusions: Involvement of stakeholders is vital early in the development of a complex intervention. Stakeholders have clear and relevant views on what a virtual clinic system should provide, and these views can be captured and synthesized with relative ease. This work has led to the design of a system that is able to meet user needs and is currently being evaluated in a pilot study