6,394 research outputs found
Rotational properties of the Haumea family members and candidates: Short-term variability
Haumea is one of the most interesting and intriguing transneptunian objects
(TNOs). It is a large, bright, fast rotator, and its spectrum indicates nearly
pure water ice on the surface. It has at least two satellites and a dynamically
related family of more than ten TNOs with very similar proper orbital
parameters and similar surface properties. The Haumean family is the only one
currently known in the transneptunian belt. Various models have been proposed
but the formation of the family remains poorly understood. In this work, we
have investigated the rotational properties of the family members and
unconfirmed family candidates with short-term variability studies, and report
the most complete review to date. We present results based on five years of
observations and report the short-term variability of five family members, and
seven candidates. The mean rotational periods, from Maxwellian fits to the
frequency distributions, are 6.27+/-1.19 h for the confirmed family members,
6.44+/-1.16 h for the candidates, and 7.65+/-0.54 h for other TNOs (without
relation to the family). According to our study, there is a suggestion that
Haumea family members rotate faster than other TNOs, however, the sample of
family member is still too limited for a secure conclusion. We also highlight
the fast rotation of 2002 GH32. This object has a 0.36+/-0.02 mag amplitude
lightcurve and a rotational period of about 3.98 h. Assuming 2002 GH32 is a
triaxial object in hydrostatic equilibrium, we derive a lower limit to the
density of 2.56 g cm^-3. This density is similar to Haumea's and much more
dense than other small TNO densities.Comment: Accepted for publication, A
A Survey for Satellites of Venus
We present a systematic survey for satellites of Venus using the
Baade-Magellan 6.5 meter telescope and IMACS wide-field CCD imager at Las
Campanas observatory in Chile. In the outer portions of the Hill sphere the
search was sensitive to a limiting red magnitude of about 20.4, which
corresponds to satellites with radii of a few hundred meters when assuming an
albedo of 0.1. In the very inner portions of the Hill sphere scattered light
from Venus limited the detection to satellites of about a kilometer or larger.
Although several main belt asteroids were found, no satellites (moons) of Venus
were detected.Comment: Published in July 2009 (Sheppard, S. and Trujillo, C. 2009, Icarus,
202, 12-16.
A Survey for Outer Satellites of Mars: Limits to Completeness
We surveyed the Hill sphere of Mars for irregular satellites. Our search
covered nearly the entire Hill Sphere, but scattered light from Mars excluded
the inner few arcminutes where the satellites Phobos and Deimos reside. No new
satellites were found to an apparent limiting red magnitude of 23.5, which
corresponds to radii of about 0.09 km using an albedo of 0.07.Comment: 5 figures (1 color), 2 Tables, to appear in AJ Nov. 200
Dynamic Resonance Effects in the Statistical Distributions of Asteroids and Comets
Some principles in the distribution of Centaurs and the "Scattered Disk"
objects, as well as the Kuiper belt objects for its semi-major axes,
eccentricities and inclinations of the orbits have been investigated. It has
been established, that more than a half from them move on the resonant orbits
and that is what has been predicted earlier. The divergence of the maximum in
the observable distribution of the objects of the Kuiper belt for the
semi-major axes with an exact orbital resonance has been interpreted.Comment: 7 pages, 5 figures, 1 table. International Conference "100 years
since Tunguska phenomenon: Past, present and future", (June 26-28, 2008.
Russia, Moscow), International Conference "Modern problems of astronomy"
(August 12-18, 2007, Ukraine, Odessa
Twin-Photon Confocal Microscopy
A recently introduced two-channel confocal microscope with correlated
detection promises up to 50% improvement in transverse spatial resolution
[Simon, Sergienko, Optics Express {\bf 18}, 9765 (2010)] via the use of photon
correlations. Here we achieve similar results in a different manner,
introducing a triple-confocal correlated microscope which exploits the
correlations present in optical parametric amplifiers. It is based on tight
focusing of pump radiation onto a thin sample positioned in front of a
nonlinear crystal, followed by coincidence detection of signal and idler
photons, each focused onto a pinhole. This approach offers further resolution
enhancement in confocal microscopy
Towards understanding the availability of physiotherapy services in rural Australia
Introduction: A recent exploration of factors affecting rural physiotherapy service provision revealed considerable variation in services available between communities of the study. Multiple factors combined to influence local service provision, including macro level policy and funding decisions, service priorities and fiscal constraints of regional health services and capacity and capabilities at the physiotherapy service level. The aim of this article is to describe the variation in local service provision, the factors influencing service provision and the impact on availability of physiotherapy services.
Methods: A priority-sequence mixed methods design structured the collection and integration of qualitative and quantitative data. The investigation area, a large part of one Australian state, was selected for the number of physiotherapy services and feasibility of conducting site visits. Stratified purposive sampling permitted exploration of rural physiotherapy with subgroups of interest, including physiotherapists, their colleagues, managers, and other key decision makers. Participant recruitment commenced with public sector physiotherapists and progressed to include private practitioners, team colleagues and managers. Surveys were mailed to key physiotherapy contacts in each public sector service in the area for distribution to physiotherapists, their colleagues and managers within their facility. Private physiotherapist principals working in the same communities were invited by the researcher to complete the physiotherapy survey. The survey collected demographic data, rural experience, work setting and number of colleagues, services provided, perspectives on factors influencing service provision and decisions about service provision. Semi-structured interviews were conducted with consenting physiotherapists and other key decision makers identified by local physiotherapists. Quantitative survey data were recorded in spreadsheets and analysed using descriptive statistics. Interviews were recorded and transcribed verbatim, with transcripts provided to participants for review. Open-ended survey questions and interview transcripts were analysed thematically.
Results: Surveys were received from 11/25 (44%) of facilities in the investigation area, with a response rate of 29.4% (16/54) from public sector physiotherapists. A further 18 surveys were received: five from principals of private physiotherapy practices and 13 from colleagues and managers. Nineteen interviews were conducted: with 14 physiotherapists (nine public, five private), four other decision makers and one colleague. Three decision makers declined an interview. The variation in physiotherapy service availability between the 11 communities of this study prompted the researchers to consider how such variation could be reflected. The influential factors that emerged from participant comments included rurality and population, size and funding model of public hospitals, the number of public sector physiotherapists and private practices, and the availability of specialised paediatric and rehabilitation services. The factors described by participants were used to develop a conceptual framework or index of rural physiotherapy availability.
Conclusions: It is important to make explicit the link between workforce maldistribution, the resultant rural workforce shortages and the implications for local service availability. This study sought to do so by investigating physiotherapy service provision within the rural communities of the investigation area. In doing so, varying levels of availability emerged within local communities. A conceptual framework combining key influencing factors is offered as a way to reflect the availability of physiotherapy services
“Your Brain Isn’t All Backwards”: Asexual Young Women’s Narratives of Sexual Healthism
Scholarship on asexuality is a growing but underexplored area in the social sciences. In the U.S., asexual people (i.e., individuals who do not experience sexual attraction) navigate a society in which being a sexual person is regarded as a normal and even compulsory aspect of human health and subjectivity. Utilizing an asexual subsample from a broader study of queer young women, this article integrates Foucault’s theorizing around sexuality and repression with scholarship on healthism to examine how discourses of sexual healthism operate among asexual young women in the U.S. South. We argue that in rejecting theories of sexual repression and compulsory “healthy” sexuality, asexual young women both confirm and resist the moral authority and power of religious and health discourses to affirm their identities and find language and communities to make their experiences more intelligible to themselves and others. Our analysis advances emerging scholarship on sexual healthism and its discursive and material effects on marginalized groups
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