3,345 research outputs found
Astrometric and photometric initial mass functions from the UKIDSS Galactic Clusters Survey - II. The Alpha Persei open cluster
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society Ā© 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We present the results of a deep (J = 19.1mag) infrared (ZYJHK) survey over the full Ī± Per open cluster extracted from the Data Release 9 of the United Kingdom Infrared Telescope Infrared Deep Sky Survey Galactic Clusters Survey (UKIDSS). We have selected ā¼700 cluster member candidates in ā¼56 square degrees in Ī± Per by combining photometry in five near-infrared passbands and proper motions derived from the multiple epochs provided by the UKIDSS Galactic Clusters Survey (GCS) Data Release 9 (DR9). We also provide revised membership for all previously published Ī± Per low-mass stars and brown dwarfs recovered in GCS based on the new photometry and astrometry provided by DR9. We find no evidence of K-band variability in members of Ī± Per with dispersion less than 0.06-0.09mag. We employed two independent but complementary methods to derive the cluster luminosity and mass functions: a probabilistic analysis and a more standard approach consisting of stricter astrometric and photometric cuts. We find that the resulting luminosity and mass functions obtained from both methods are consistent. We find that the shape of the Ī± Per mass function is similar to that of the Pleiades although the characteristic mass may be higher after including higher mass data from earlier studies (the dispersion is comparable). We conclude that the mass functions of Ī± Per, the Pleiades and Praesepe are best reproduced by a log-normal representation similar to the system field mass function although with some variation in the characteristic mass and dispersion values.Peer reviewe
Electrical control of Kondo effect and superconducting transport in a side-gated InAs quantum dot Josephson junction
We measure the non-dissipative supercurrent in a single InAs self-assembled
quantum dot (QD) coupled to superconducting leads. The QD occupation is both
tuned by a back-gate electrode and lateral side-gate. The geometry of the
side-gate allows tuning of the QD-lead tunnel coupling in a region of constant
electron number with appropriate orbital state. Using the side-gate effect we
study the competition between Kondo correlations and superconducting pairing on
the QD, observing a decrease in the supercurrent when the Kondo temperature is
reduced below the superconducting energy gap in qualitative agreement with
theoretical predictions
Inter-band magnetoplasmons in mono- and bi-layer graphene
Collective excitations spectrum of Dirac electrons in mono and bilayer
graphene in the presence of a uniform magnetic field is investigated.
Analytical results for inter-Landau band plasmon spectrum within the
self-consistent-field approach are obtained. SdH type oscillations that are a
monotonic function of the magnetic field are observed in the plasmon spectrum
of both mono- and bi-layer graphene systems. The results presented are also
compared with those obtained in conventional 2DEG. The chiral nature of the
quasiparticles in mono and bilayer graphene system results in the observation
of and Berry's phase in the SdH- type oscillations in the plasmon
spectrum.Comment: 9 pages, 2 figure
Superlattice Magnetophonon Resonances in Strongly Coupled InAs/GaSb Superlattices
We report an experimental study of miniband magnetoconduction in
semiconducting InAs/GaSb superlattices. For samples with miniband widths below
the longitudinal optical phonon energy we identify a new superlattice
magnetophonon resonance (SLMPR) caused by resonant scattering of electrons
across the mini-Brillouin zone. This new resonant feature arises directly from
the drift velocity characteristics of the superlattice dispersion and total
magnetic quantisation of the superlattice Landau level minibands.Comment: 9 pages, 8 figures, submitted to Phys. Rev.
Addressing health inequities for same sex attracted women in New South Wales, Australia, who use drugs
ACONās Alcohol and Other Drugs Program provides a Needle Syringe Program, peerbased harm reduction programs, drug education targeted at members of the lesbian, gay, bisexual and transgender (LGBT) community, and counselling services. The Lesbian Health Project works with lesbians and other same-sex attracted (SSA) women to improve their health and wellbeing through health promotion, peer education and community development programs as well as providing capacity development for mainstream service providers. In Australia, LGBT people have considerably higher rates of drug use than the general population. While there is considerable funding support from Australian state and federal governments for education interventions that address gay menās drug use, it has been more difficult to address the needs of lesbians and other SSA women. Efforts to address lesbian health needs are hampered by lack of research, poor understanding of the issues by potential funding bodies, and the lack of a single defining health issue (such as HIV among gay men) around which to focus advocacy efforts. Equally problematic is the absence of consideration given to lesbians and SSA women in any Australian national and state health policies. In response to the consistently low uptake of both harm reduction and treatment services by SSA women, ACON has successfully advocated with a major funder of our drug and alcohol work to re-allocate some existing funding to produce SSAwomen specific drug resources, in the interests of equity. This project (currently under development) seeks to engage with networks of SSA women who use drugs and who do not normally access ACONās drugs and alcohol services, to produce resources that āspeak toā their issue
Gap opening in the zeroth Landau level in gapped graphene: Pseudo-Zeeman splitting in an angular magnetic field
We present a theoretical study of gap opening in the zeroth Landau level in
gapped graphene as a result of pseudo-Zeeman interaction. The applied magnetic
field couples with the valley pseudospin degree of freedom of the charge
carriers leading to the pseudo-Zeeman interaction. To investigate its role in
transport at the Charge Neutrality Point (CNP), we study the integer quantum
Hall effect (QHE) in gapped graphene in an angular magnetic field in the
presence of pseudo-Zeeman interaction. Analytical expressions are derived for
the Hall conductivity using Kubo-Greenwood formula. We also determine the
longitudinal conductivity for elastic impurity scattering in the first Born
approximation. We show that pseudo-Zeeman splitting leads to a minimum in the
collisional conductivity at high magnetic fields and a zero plateau in the Hall
conductivity. Evidence for activated transport at CNP is found from the
temperature dependence of the collisional conductivity.Comment: 20 pages, 4 figures, Accepted in J. Phys. Condensed matte
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Legal guardians understand how children with the human immunodeficiency virus perceive quality of life and stigma
AIM: This aim of this study was to describe how legal guardians assessed health-related quality of life and HIV-related stigma in children with the human immunodeficiency virus (HIV) compared to the children's own ratings.
METHODS: A cross-sectional nationwide study was performed to compare how 37 children aged from eight to 16Ā years of age with perinatal HIV, and their legal guardians, assessed the children's health-related quality of life and HIV-related stigma. Data were collected using the 37-item DISABKIDS Chronic Generic Module and a short eight-item version of the HIV stigma scale.
RESULTS: Intraclass correlations indicated concordance between the legal guardians' ratings and the children's own ratings of the child's health-related quality of life and HIV-related stigma. There were no statistically significant differences between the ratings of the two groups and gender did not have any impact on the results. Both groups indicated that the children had concerns about being open about their HIV status.
CONCLUSION: The results of this study indicated that legal guardians understood how their children perceived their health-related quality of life and HIV-related stigma. The results also indicated the need for interventions to support both the children and legal guardians when it came to disclosing the child's HIV status
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