2,444 research outputs found
Gender Politics and Secure Services For Women: Reflections on a study of staff understandings of challenging behaviour.
This paper discusses the findings of a Q methodological study that investigated the complexity of professional understandings of (attitudes towards) residents in a secure unit for women with learning disabilities and challenging behaviours. Particular attention is afforded to the critical debate regarding women in psychiatric and secure care, including the significant contribution made to this literature by feminist perspectives. A multiprofessional group of staff (n = 38) participated in the study and nine distinct accounts of women's challenging behaviour are described. Despite a considerable amount of recent policy concern with the position of women in psychiatric services, the findings of this research suggest that many front line staff are reluctant to highlight gender in their explanations of women's behaviour. This supports the assertion by Williams et al. (2001), who were involved in the National Gender Training Initiative (NGTI), that most critical theorizing about women's mental health has had minimal impact at the level of individuals’ understandings of these important issues. This state of affairs suggests a powerful case for the expansion of staff training as provided in the NGTI, which makes gender central to understanding and emphasizes feminist perspectives
Security of continuous-variable quantum key distribution against general attacks
We prove the security of Gaussian continuous-variable quantum key
distribution against arbitrary attacks in the finite-size regime. The novelty
of our proof is to consider symmetries of quantum key distribution in phase
space in order to show that, to good approximation, the Hilbert space of
interest can be considered to be finite-dimensional, thereby allowing for the
use of the postselection technique introduced by Christandl, Koenig and Renner
(Phys. Rev. Lett. 102, 020504 (2009)). Our result greatly improves on previous
work based on the de Finetti theorem which could not provide security for
realistic, finite-size, implementations.Comment: 5 pages, plus 11 page appendi
Evolution of entanglement within classical light states
We investigate the evolution of quantum correlations over the lifetime of a
multi-photon state. Measurements reveal time-dependent oscillations of the
entanglement fidelity for photon pairs created by a single semiconductor
quantum dot. The oscillations are attributed to the phase acquired in the
intermediate, non-degenerate, exciton-photon state and are consistent with
simulations. We conclude that emission of photon pairs by a typical quantum dot
with finite polarisation splitting is in fact entangled in a time-evolving
state, and not classically correlated as previously regarded
Comparison of the Interactions of Transferrin Receptor and Transferrin Receptor 2 with Transferrin and the Hereditary Hemochromatosis Protein HFE
The transferrin receptor (TfR) interacts with two proteins important for iron metabolism, transferrin (Tf) and HFE, the protein mutated in hereditary hemochromatosis. A second receptor for Tf, TfR2, was recently identified and found to be functional for iron uptake in transfected cells (Kawabata, H., Germain, R. S., Vuong, P. T., Nakamaki, T., Said, J. W., and Koeffler, H. P. (2000) J. Biol. Chem. 275, 16618-16625). TfR2 has a pattern of expression and regulation that is distinct from TfR, and mutations in TfR2 have been recognized as the cause of a non-HFE linked form of hemochromatosis (Camaschella, C., Roetto, A., Cali, A., De Gobbi, M., Garozzo, G., Carella, M., Majorano, N., Totaro, A., and Gasparini, P. (2000) Nat. Genet. 25, 14-15). To investigate the relationship between TfR, TfR2, Tf, and HFE, we performed a series of binding experiments using soluble forms of these proteins. We find no detectable binding between TfR2 and HFE by co-immunoprecipitation or using a surface plasmon resonance-based assay. The affinity of TfR2 for iron-loaded Tf was determined to be 27 nM, 25-fold lower than the affinity of TfR for Tf. These results imply that HFE regulates Tf-mediated iron uptake only from the classical TfR and that TfR2 does not compete for HFE binding in cells expressing both forms of TfR
Giant Stark effect in the emission of single semiconductor quantum dots
We study the quantum-confined Stark effect in single InAs/GaAs quantum dots
embedded within a AlGaAs/GaAs/AlGaAs quantum well. By significantly increasing
the barrier height we can observe emission from a dot at electric fields of
-500 kV/cm, leading to Stark shifts of up to 25 meV. Our results suggest this
technique may enable future applications that require self-assembled dots with
transitions at the same energy
Tailoring Topological Edge States with Photonic Crystal Nanobeam Cavities
The realization of topological edge states (TESs) in photonic systems has
provided unprecedented opportunities for manipulating light in novel manners.
The Su-Schrieffer-Heeger (SSH) model has recently gained significant attention
and has been exploited in a wide range of photonic platforms to create TESs. We
develop a photonic topological insulator strategy based on SSH photonic crystal
nanobeam cavities. In contrast to the conventional photonic SSH schemes which
are based on alternately tuned coupling strength in one-dimensional lattice,
our proposal provides higher flexibility and allows tailoring TESs by
manipulating mode coupling in a two-dimensional manner. We reveal that the
proposed hole-array based nanobeams in a dielectric membrane can selectively
tailor single or double TESs in the telecommunication region by controlling the
coupling strength of the adjacent SSH nanobeams in both vertical and horizontal
directions. Our finding provides an in-depth understanding of the SSH model,
and allows an additional degree of freedom in exploiting the SSH model for
integrated topological photonic devices with unique properties and
functionalities
High performance single photon sources from photolithographically defined pillar microcavities
We demonstrate that single photons can be generated from single InAs/GaAs quantum dots in photolithographically defined pillar microcavities. Pillars with a 1.9 µm diameter cavity show a four fold enhancement in the radiative decay rate due to the Purcell effect and a photon collection efficiency into a lens of up to 10%. Measurements of the second order correlation function reveal a greater than fifty fold reduction in the multi-photon emission rate compared to a laser of the same intensity
Probing nonstandard interactions with reactor neutrinos
New limits on the weak mixing angle and on the electron neutrino effective
charge radius in the low energy regime, below 100 MeV, are obtained from a
combined fit of all electron-(anti)neutrino electron elastic scattering
measurements. We have included the recent TEXONO measurement with a CsI (Tl)
detector. Only statistical error of this measurement has been taken into
account. Weak mixing angle is found to be sin^2 theta_W = 0.255 +0.022 -0.023.
The electron neutrino effective charge radius squared is bounded to be r^2 =
(0.9 +0.9 -1.0) x 10^{-32} cm^2. The sensitivity of future low energy neutrino
experiments to nonstandard interactions of neutrinos with quarks is also
discussed.Comment: 3 pages, 2 figures, talk given at the Neutrino Oscillation Workshop
(NOW 2008), Otranto, Italy, September 6-13, 2008. Misprints correcte
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