8,648 research outputs found
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
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