1,318 research outputs found
The Changing Narratives of Death, Dying, and HIV in the United Kingdom
Death and infection were closely linked from the start of the HIV epidemic, until successful treatments became available. The initial impact of mostly young, gay men dying from HIV was powerful in shaping UK responses. Neoliberal discourses developed at the same time, particularly focusing on how citizens (rather than the state) should take responsibility to improve health. Subsequently “successful ageing” became an allied discourse, further marginalising death discussions. Our study reflected on a broad range of meanings around death within the historical UK epidemic, to examine how dying narratives shape contemporary HIV experiences. Fifty-one participants including people living with HIV, professionals, and activists were recruited for semistructured interviews. Assuming a symbolic interactionist framework, analysis highlighted how HIV deaths were initially experienced as not only traumatic but also energizing, leading to creativity. With effective antiretrovirals, dying changed shape (e.g., loss of death literacy), and better integration of palliative care was recommended
Origin Of the enhanced flexoelectricity of relaxor ferroelectrics
We have measured the bending-induced polarization of Pb(Mg1/3Nb2/3)O3-PbTiO3
single crystals with compositions at the relaxor-ferroelectric phase boundary.
The crystals display very large flexoelectricity, with flexocoupling
coefficients an order of magnitude bigger than the theoretical upper limit set
by the theories of Kogan and Tagantsev. This enhancement persists in the
paraphrase up to a temperature T* that coincides with the start of elastic
softening in the crystals. Analysis of the temperature dependence and
cross-correlation between flexoelectric, dielectric and elastic properties
indicates that the large bendinginduced polarization of relaxor ferroelectrics
is not caused by intrinsically giant flexoelectricity, but by the reorientation
of polar nanotwins that become ferroelastically active below T*
Effect of manganese doping on the size effect of lead zirconate titanate thin films and the extrinsic nature of dead layers
We have investigated the size effect in lead zirconate titanate (PZT) thin
films with a range of manganese (Mn) doping concentrations. We found that the
size effect in the conventional Pt/PZT/Pt thin-film capacitors could be
systematically reduced and almost completely eliminated by increasing Mn doping
concentration. The interfacial layer at the electrode-film interface appears to
disappear almost entirely for the PZT films with 2% Mn doping levels, confirmed
by the fits using the conventional in-series capacitor model. Our work
indicates that the size effect in ferroelectrics is extrinsic in nature,
supporting the work by Saad et al. Other implications of our results have also
been discussed. By comparing a variety of experimental studies in the
literature we propose a scenario that the dead layer between PZT (or barium
strontium titanate, BST) and metal electrodes such as Pt and Au might have a
defective pyrochlore/fluorite structure (possibly with a small portion of
ferroelectric perovskite phase).Comment: 21 pages, 6 figure
A Collimation Experiment with Protons at 120 GeV
We present the preliminary results of a two-stage collimation experiment made with a 120 GeV coasting proton beam in the SPS at CERN
HIV-related stigma in the UK then and now: to what extent are we on track to eliminate stigma? A qualitative investigation
Background
The introduction of effective antiretroviral treatment in the late 1990s led to the perception that HIV was a chronic but manageable condition. Nevertheless, stigma remains one of the major hurdles for people living with HIV (PLWH) to accessing healthcare and biomedical preventions. Thus, Fast Track Cities has set a target of zero HIV discrimination by 2030 as part of its strategy to end HIV transmission.
Methods
Fifty-three participants from the United Kingdom, including PLWH (n = 21, 40%), health and social care workers (n = 24, 45%), and charity workers and activists (n = 13, 25%), were recruited. Semi-structured interviews investigated stigma and discrimination, focusing on both before and after the widespread use of effective antiretroviral treatment in the late 1990s. Data were analysed using a thematic approach.
Results
Before effective antiretroviral treatment narratives were shaped by two main themes: 1) the media’s role in influencing public opinion and contributing to misunderstandings of HIV transmission; and 2) personal experiences of HIV-related stigma, which for PLWH included incidents of physical violence and aggression, as well as fears of their HIV status being publicised. Contemporary narratives on stigma experiences were organised around four themes: 1) discrimination in healthcare settings; 2) stigma amongst men who have sex with men (MSM); 3) stigma towards African and Afro-Caribbean PLWH; and 4) the limits of change in public HIV-related knowledge and attitudes. Contemporary narratives indicated a reduction in enacted stigma, but continued anticipation of discrimination and self-reported shame, particularly in MSM and African and Afro-Caribbean PLWH.
Conclusion
The nature of stigma against those with HIV has evolved. The intersection of PLWH and minority groups (e.g. MSM and African and Afro-Caribbean persons) may enhance anticipatory and internalised stigma, with some suggestion that this may contribute to reduced engagement in HIV care and prevention services. Our findings indicate the need for further research in this area, as well as proactive interventions with community groups to enhance knowledge of HIV
Bacterial viruses enable their host to acquire antibiotic resistance genes from neighbouring cells
Prophages are quiescent viruses located in the chromosomes of bacteria. In the human
pathogen, Staphylococcus aureus, prophages are omnipresent and are believed to be responsible
for the spread of some antibiotic resistance genes. Here we demonstrate that release of
phages from a subpopulation of S. aureus cells enables the intact, prophage-containing
population to acquire beneficial genes from competing, phage-susceptible strains present in
the same environment. Phage infection kills competitor cells and bits of their DNA are
occasionally captured in viral transducing particles. Return of such particles to the prophagecontaining
population can drive the transfer of genes encoding potentially useful traits such
as antibiotic resistance. This process, which can be viewed as ‘auto-transduction’, allows
S. aureus to efficiently acquire antibiotic resistance both in vitro and in an in vivo virulence
model (wax moth larvae) and enables it to proliferate under strong antibiotic selection
pressure. Our results may help to explain the rapid exchange of antibiotic resistance genes
observed in S. aureus
Strain Gradients in Epitaxial Ferroelectrics
X-ray analysis of ferroelectric thin layers of Ba1/2Sr1/2TiO3 with different
thickness reveals the presence of internal strain gradients across the film
thickness and allows us to propose a functional form for the internal strain
profile. We use this to calculate the direct influence of strain gradient,
through flexoelectric coupling, on the degradation of the ferroelectric
properties of thin films with decreasing thickness, in excellent agreement with
the observed behaviour. This work highlights the link between strain relaxation
and strain gradients in epitaxial films, and shows the pressing need to avoid
strain gradients in order to obtain thin ferroelectrics with bulk-like
properties.Comment: 4 pages, 3 embedded figures (1 color), revTex
Cascade Simulations for the LHC Betatron Cleaning Insertion
A cascade calculation is done in the IR7 betatron cleaning insertion of LHC. It uses a detailed map of the primary losses and an accurate model of the straight section. One aim is to design a compact shielding which fits in the tight section of the tunnel. The same study allows to define radiation hardness properties of the equipment to be installed in the section and to locate areas of low activi ty for the installation of sensitive equipment
Fast Ramping Superconducting Magnet Design Issues for Future Injector Upgrades at CERN
An upgrade of the LHC injection chain, and especially the sequence of PS and SPS, up to an extraction energy of 1Â TeV, is one of the steps considered to improve the performance of the whole accelerator complex. The magnets for this upgrade require central magnetic field from 2 T (for a PS upgrade) to 4.5 T (for an SPS upgrade), for which superconducting magnets are a candidate. Due to the fast field sweep rate of the magnets (from about 1.5 T/s to 2.5Â T/s), internal heating from eddy and persistent current effects (AC loss) must be minimized. In this paper we discuss a rationale for the design and optimization of fast ramped superconducting accelerator magnets, specifically aimed at the LHC injectors. We introduce a design parameter, the product of bore field and field ramp-rate, providing a measure of the magnet performance, and we apply it to choose the design range for a technology demonstration magnet. We finally discuss the dependence of key design parameters on the bore field and the bore diameter, to provide an approximate scaling and guidelines for critical R&D
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