499 research outputs found
Harm minimisation for the management of self-harm: a mixed-methods analysis of electronic health records in secondary mental healthcare
BACKGROUND:
Prevalence of self-harm in the UK was reported as 6.4% in 2014. Despite sparse evidence for effectiveness, guidelines recommend harm minimisation; a strategy in which people who self-harm are supported to do so safely.
AIMS:
To determine the prevalence, sociodemographic and clinical characteristics of those who self-harm and practise harm minimisation within a London mental health trust.
METHOD:
We included electronic health records for patients treated by South London and Maudsley NHS Trust. Using an iterative search strategy, we identified patients who practise harm minimisation, then classified the approaches using a content analysis. We compared the sociodemographic characteristics with that of a control group of patients who self-harm and do not use harm minimisation.
RESULTS:
In total 22 736 patients reported self-harm, of these 693 (3%) had records reporting the use of harm-minimisation techniques. We coded the approaches into categories: (a) ‘substitution’ (>50% of those using harm minimisation), such as using rubber bands or using ice; (b) ‘simulation’ (9%) such as using red pens; (c) ‘defer or avoid’ (7%) such as an alternative self-injury location; (d) ‘damage limitation’ (9%) such as using antiseptic techniques; the remainder were unclassifiable (24%). The majority of people using harm minimisation described it as helpful (>90%). Those practising harm minimisation were younger, female, of White ethnicity, had previous admissions and were less likely to have self-harmed with suicidal intent.
CONCLUSIONS:
A small minority of patients who self-harm report using harm minimisation, primarily substitution techniques, and the large majority find harm minimisation helpful. More research is required to determine the acceptability and effectiveness of harm-minimisation techniques and update national clinical guidelines
Realistic atomistic structure of amorphous silicon from machine-learning-driven molecular dynamics
Amorphous silicon (a-Si) is a widely studied noncrystalline material, and yet the subtle details of its atomistic structure are still unclear. Here, we show that accurate structural models of a-Si can be obtained using a machine-learning-based interatomic potential. Our best a-Si network is obtained by simulated cooling from the melt at a rate of 1011 K/s (that is, on the 10 ns time scale), contains less than 2% defects, and agrees with experiments regarding excess energies, diffraction data, and 29Si NMR chemical shifts. We show that this level of quality is impossible to achieve with faster quench simulations. We then generate a 4096-atom system that correctly reproduces the magnitude of the first sharp diffraction peak (FSDP) in the structure factor, achieving the closest agreement with experiments to date. Our study demonstrates the broader impact of machine-learning potentials for elucidating structures and properties of technologically important amorphous materials
Goal-oriented a posteriori error estimation for the travel time functional in porous media flows
In this article we consider the a posteriori error estimation and adaptive mesh refinement for the numerical approximation of the travel time functional arising in porous media flows. The key application of this work is in the safety assessment of radioactive waste facilities; in this setting, the travel time functional measures the time taken for a non-sorbing radioactive solute, transported by groundwater, to travel from a potential site deep underground to the biosphere. To ensure the computability of the travel time functional, we employ a mixed formulation of Darcy's law and conservation of mass, together with Raviart-Thomas H(div) conforming finite elements. The proposed a posteriori error bound is derived based on a variant of the standard Dual-Weighted-Residual approximation, which takes into account the lack of smoothness of the underlying functional of interest. The proposed adaptive refinement strategy is tested on both a simple academic test case and a problem based on the geological units found at the Sellafield site in the UK
Radiotherapy response evaluation using FDG PET-CT - established and emerging applications.
Radiation therapy is a common component of curative cancer treatment. However, there is a significant incidence of treatment failure. In these cases salvage surgical options are sometimes appropriate. Accurate assessment of response and early recognition of treatment success or failure is therefore critical to guide treatment decisions and impacts on survival and the morbidity of treatment. Traditionally, treatment response has depended upon anatomical measurement of disease. However, this may not correlate well with the presence of disease, especially after radiotherapy. Combined positron emission tomography and computed tomography (PET-CT) imaging employs radioactive tracers to identify molecular characteristics of tissue. PET imaging exploits the fact that malignancies have characteristic molecular profiles which differ compared to surrounding tissues. The complementary anatomical and functional information facilitates accurate non-invasive assessment of surrogate biomarkers of disease activity. This article reviews the rationale for PET-CT response assessment in radiation oncology, describing current uses of 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) PET-CT in treatment response following radiotherapy in head and neck, oesophageal, rectal and brain tumours. Emerging applications of FDG PET-CT in cervical and lung carcinomas and hepato-pancreatico-biliary (HPB) tumours particularly pancreatic carcinoma and liver metastases (post selective internal radiotherapy treatment (SIRT)) are reviewed. Finally, the limitations of FDG PET-CT are considered, highlighting areas for future development
Numerical and Experimental Investigation of Circulation in Short Cylinders
In preparation for an experimental study of magnetorotational instability
(MRI) in liquid metal, we explore Couette flows having height comparable to the
gap between cylinders, centrifugally stable rotation, and high Reynolds number.
Experiments in water are compared with numerical simulations. Simulations show
that endcaps corotating with the outer cylinder drive a strong poloidal
circulation that redistributes angular momentum. Predicted azimuthal flow
profiles agree well with experimental measurements. Spin-down times scale with
Reynolds number as expected for laminar Ekman circulation; extrapolation from
two-dimensional simulations at agrees remarkably well with
experiment at . This suggests that turbulence does not dominate
the effective viscosity. Further detailed numerical studies reveal a strong
radially inward flow near both endcaps. After turning vertically along the
inner cylinder, these flows converge at the midplane and depart the boundary in
a radial jet. To minimize this circulation in the MRI experiment, endcaps
consisting of multiple, differentially rotating rings are proposed. Simulations
predict that an adequate approximation to the ideal Couette profile can be
obtained with a few rings
Virtual discussions to support climate risk decision making on farms
Climate variability represents a significant risk to farming enterprises. Effective extension of climate information may improve climate risk decision making and adaptive management responses to climate variability on farms. This paper briefly reviews current agricultural extension approaches and reports stakeholder responses to new web-based virtual world ‘discussion-support’ tools developed for the Australian sugar cane farming industry. These tools incorporate current climate science and sugar industry better management practices, while leveraging the social-learning aspects of farming, to provide a stimulus for discussion and climate risk decision making. Responses suggest that such virtual world tools may provide effective support for climate risk decision making on Australian sugar cane farms. Increasing capacity to deliver such tools online also suggests potential to engage large numbers of farmers globally
Observational Implications of Precessing Protostellar Discs and Jets
We consider the dynamics of a protostellar disc in a binary system where the
disc is misaligned with the orbital plane of the binary, with the aim of
determining the observational consequences for such systems. The disc wobbles
with a period approximately equal to half the binary's orbital period and
precesses on a longer timescale. We determine the characteristic timescale for
realignment of the disc with the orbital plane due to dissipation. If the
dissipation is determined by a simple isotropic viscosity then we find, in line
with previous studies, that the alignment timescale is of order the viscous
evolution timescale. However, for typical protostellar disc parameters, if the
disc tilt exceeds the opening angle of the disc, then tidally induced shearing
within the disc is transonic. In general, hydrodynamic instabilities associated
with the internally driven shear result in extra dissipation which is expected
to drastically reduce the alignment timescale. For large disc tilts the
alignment timescale is then comparable to the precession timescale, while for
smaller tilt angles , the alignment timescale varies as . We discuss the consequences of the wobbling, precession and
rapid realignment for observations of protostellar jets and the implications
for binary star formation mechanisms.Comment: MNRAS, in press. 10 pages. Also available at
http://www.ast.cam.ac.uk/~mbat
Combination of bevacizumab and 2-weekly pegylated liposomal doxorubicin as first-line therapy for locally recurrent or metastatic breast cancer. A multicenter, single-arm phase II trial (SAKK 24/06)
Background: Pegylated liposomal doxorubicin (PLD) and bevacizumab are active agents in the treatment of metastatic breast cancer (MBC). We carried out a multicenter, single-arm phase II trial to evaluate the toxicity and efficacy of PLD and bevacizumab as first-line treatment in MBC patients. Methods: Bevacizumab (10 mg/kg) and PLD (20 mg/m2) were infused on days 1 and 15 of a 4-week cycle for a maximum of six cycles. Thereafter, bevacizumab monotherapy was continued at the same dose until progression or toxicity. The primary objective was safety and tolerability, and the secondary objective was to evaluate efficacy of the combination. Results: Thirty-nine of 43 patients were assessable for the primary end point. Eighteen of 39 patients (46%, 95% confidence interval 30% to 63%) had a grade 3 toxicity. Sixteen (41%) had grade 3 palmar-plantar erythrodysesthesia, one had grade 3 mucositis, and one severe cardiotoxicity. Secondary end point of overall response rate among 43 assessable patients was 21%. Conclusions: In this nonrandomized single-arm trial, the combination of bimonthly PLD and bevacizumab in locally recurrent and MBC patients demonstrated higher than anticipated toxicity while exhibiting only modest activity. Based on these results, we would not consider this combination for further investigation in this settin
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