1,160 research outputs found
The spin-half Heisenberg antiferromagnet on two Archimedian lattices: From the bounce lattice to the maple-leaf lattice and beyond
We investigate the ground state of the two-dimensional Heisenberg
antiferromagnet on two Archimedean lattices, namely, the maple-leaf and bounce
lattices as well as a generalized - model interpolating between both
systems by varying from (bounce limit) to (maple-leaf
limit) and beyond. We use the coupled cluster method to high orders of
approximation and also exact diagonalization of finite-sized lattices to
discuss the ground-state magnetic long-range order based on data for the
ground-state energy, the magnetic order parameter, the spin-spin correlation
functions as well as the pitch angle between neighboring spins. Our results
indicate that the "pure" bounce () and maple-leaf () Heisenberg
antiferromagnets are magnetically ordered, however, with a sublattice
magnetization drastically reduced by frustration and quantum fluctuations. We
found that magnetic long-range order is present in a wide parameter range and that the magnetic order parameter varies only
weakly with . At a direct first-order transition to
a quantum orthogonal-dimer singlet ground state without magnetic long-range
order takes place. The orthogonal-dimer state is the exact ground state in this
large- regime, and so our model has similarities to the Shastry-Sutherland
model. Finally, we use the exact diagonalization to investigate the
magnetization curve. We a find a 1/3 magnetization plateau for and another one at 2/3 of saturation emerging only at large .Comment: 9 pages, 10 figure
A controlled trial of the effectiveness of a diabetes education programme in a multi-ethnic community in Glasgow [ISRCT28317455]
BACKGROUND: Epidemiologic data have shown that the prevalence of Type 2 diabetes varies with ethnic origin. Type 2 diabetes is up to four times more common in British South Asians than in the indigenous white population. The aim of this study was to develop a culturally appropriate educational intervention programme for South Asians with Type 2 diabetes. We then investigated whether this intervention could produce an improvement, and finally whether any improvement was greater than background changes in knowledge in comparison groups. METHODS: A multi-site prospective, randomised controlled study was conducted in all day care centres and three general practice registers with high proportion patients from different ethnic minority groups in Glasgow, Scotland. The intervention consisted of 18 educational sessions in 6 separate programmes. A modified questionnaire was used to measure the knowledge, attitudes, and practice of diabetes before and after intervention. RESULTS: Baseline assessment showed that Indian and Pakistani subjects had less knowledge about diabetes, regarded the disease less seriously, and had a lesser understanding of the relationship between control and complications than the white population. No differences in initial responses were found between those who completed the second assessment and those who did not. The intervention group showed significant improvements in scores for Knowledge (+12.5%); Attitudes toward seriousness (+13.5%), complications (+8.1%), Practice (+20.0%). However there were also changes in the ethnic control group scores; respectively +5.0%, +16.3% (significant P < 0.001), +1.5%, +1.7%. The single white control group also showed some improvements; respectively +12.2%, +12.4% (P = 0.04), +6.0%, +25.0% (P = 0.007), but the differences in improvement between these two control groups were not significant. Overall, the improvement seen was similar in both intervention and ethnic control groups and there was no significant difference in the amount of change (P = 0.36 CI -0.9 to +2.6). CONCLUSION: This study has shown that conducting a culturally-competent educational intervention in patients with Type 2 diabetes from ethnic minority groups is feasible and can improve their knowledge and attitudes and practice. However there was no net benefit compared with the control group
Epigenetic and transcriptome profiling identifies a population of visceral adipose-derived progenitor cells with potential to differentiate into an endocrine pancreatic lineage
Type 1 diabetes (T1D) is characterized by the loss of insulin-producing β-cells in the pancreas. T1D can be treated using cadaveric islet transplantation, but this therapy is severely limited by a lack of pancreas donors. To develop an alternative cell source for transplantation therapy, we carried out the epigenetic characterization in nine different adult mouse tissues and identified visceral adipose-derived progenitors as a candidate cell population. Chromatin conformation, assessed using chromatin immunoprecipitation (ChIP) sequencing and validated by ChIP-polymerase chain reaction (PCR) at key endocrine pancreatic gene promoters, revealed similarities between visceral fat and endocrine pancreas. Multiple techniques involving quantitative PCR, in-situ PCR, confocal microscopy, and flow cytometry confirmed the presence of measurable (2–1000-fold over detectable limits) pancreatic gene transcripts and mesenchymal progenitor cell markers (CD73, CD90 and CD105; >98%) in visceral adipose tissue-derived mesenchymal cells (AMCs). The differentiation potential of AMCs was explored in transgenic reporter mice expressing green fluorescent protein (GFP) under the regulation of the Pdx1 (pancreatic and duodenal homeobox-1) gene promoter. GFP expression was measured as an index of Pdx1 promoter activity to optimize culture conditions for endocrine pancreatic differentiation. Differentiated AMCs demonstrated their capacity to induce pancreatic endocrine genes as evidenced by increased GFP expression and validated using TaqMan real-time PCR (at least 2–200-fold relative to undifferentiated AMCs). Human AMCs differentiated using optimized protocols continued to produce insulin following transplantation in NOD/SCID mice. Our studies provide a systematic analysis of potential islet progenitor populations using genome-wide profiling studies and characterize visceral adipose-derived cells for replacement therapy in diabetes
Development of a self-report measure of capability wellbeing for adults: the ICECAP-A
Purpose The benefits of health and social care are not confined to patient health alone and therefore broader measures of wellbeing may be useful for economic evaluation.\ud
This paper reports the development of a simple measure of capability wellbeing for adults (ICECAP-A).\ud
Methods In-depth, informant-led, interviews to identify the attributes of capability wellbeing were conducted with 36 adults in the UK. Eighteen semi-structured, repeat interviews were carried out to develop a capability-based descriptive system for the measure. Informants were purposively selected to ensure variation in socio-economic status, age, sex, ethnicity and health. Data analysis was carried out inductively and iteratively alongside interviews, and findings were used to shape the questions in later interviews.\ud
Results Five over-arching attributes of capability wellbeing were identified for the measure: ‘‘stability’’,‘‘attachment’’, ‘‘achievement’’, ‘‘autonomy’’ and ‘‘enjoyment’’. One item, with four response categories, was developed for each attribute for the ICECAP-A descriptive system.\ud
Conclusions The ICECAP-A capability measure represents a departure from traditional health economics outcome measures, by treating health status as an influence over broader attributes of capability wellbeing. Further work is required to value and validate the attributes and test the sensitivity of the ICECAP-A to healthcare interventions
Antivascular therapy of human follicular thyroid cancer experimental bone metastasis by blockade of Epidermal Growth Factor Receptor and Vascular Growth Factor Receptor phosphorylation
Patients suffering from bone metastases of Follicular Thyroid Carcinoma (FTC) have a poor prognosis because of the lack of effective treatment strategies. The overexpression of Epidermal Growth Factor Receptor (EGFR) associated with increased vascularity has been implicated in the pathogenesis of FTC and subsequent bone metastases. We hypothesized that inhibiting the phosphorylation of the EGFR and Vascular Endothelial Growth Factor Receptor (VEGFR) by AEE788, a dual tyrosine kinase inhibitor of EGFR and VEGFR, in combination with paclitaxel would inhibit experimental FTC bone lesions and preserve bone structure. We tested this hypothesis using the human WRO FTC cell line. In culture, AEE788 inhibited the EGF-mediated phosphorylation of EGFR, VEGFR2, mitogen-activated protein kinase and Akt in culture. AEE788, alone and in combination with paclitaxel, inhibited cell growth and induced apoptosis. When WRO cells were injected into the tibia of nude mice, tumor and endothelial cells within the lesions expressed phosphorylated EGFR, VEGFR, Akt and mitogen-activated protein kinase that were inhibited by the oral administration of AEE788. Therapy consisting of orally given AEE788 and i.p. injected paclitaxel induced a high level of apoptosis in tumor-associated endothelial cells and tumor cells with the inhibition of tumor growth in the bone and the preservation of bone structure. Collectively, these data show that blocking the phosphorylation of EGFR and VEGFR with AEE788 combined with paclitaxel can significantly inhibit experimental human FTC in the bone of nude mice
Learning to mark: a qualitative study of the experiences and concerns of medical markers
BACKGROUND: Although there is published research on the methods markers use in marking various types of assessment, there is relatively little information on the processes markers use in approaching a marking exercise. This qualitative paper describes the preparation and experiences of general practice (GP) teachers who undertake marking a written assessment in an undergraduate medical course. METHODS: Semi-structured interviews were conducted with seven of the 16 GP tutors on an undergraduate course. The purposive sample comprised two new markers, two who had marked for a couple of years and three experienced markers. Each respondent was interviewed twice, once following a formative assessment of a written case study, and again after a summative assessment. All interviews were audio-taped and analysed for emerging themes. A respondent validation exercise was conducted with all 16 GP tutors. RESULTS: Markers had internal concerns about their ability to mark fairly and made considerable efforts to calibrate their marking. They needed guidance and coaching when marking for the first time and adopted a variety of marking styles, reaching a decision through a number of routes. Dealing with pass/fail borderline scripts and the consequences of the mark on the student were particular concerns. Even experienced markers felt the need to calibrate their marks both internally and externally CONCLUSION: Previous experience of marking appears to improve markers' confidence and is a factor in determining the role which markers adopt. Confidence can be improved by giving clear instructions, along with examples of marking. The authors propose that one method of providing this support and coaching could be by a process of peer review of a selection of papers prior to the main marking. New markers in particular would benefit from further guidance, however they are influenced by others early on in their marking career and course organisers should be mindful of this when arranging double marking
Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering
We have measured the beam-normal single-spin asymmetry in elastic scattering
of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 =
0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely
using the elastic nucleon intermediate state, and generally agree with
calculations with significant inelastic hadronic intermediate state
contributions. A_n provides a direct probe of the imaginary component of the
2-gamma exchange amplitude, the complete description of which is important in
the interpretation of data from precision electron-scattering experiments.Comment: 5 pages, 3 figures, submitted to Physical Review Letters; shortened
to meet PRL length limit, clarified some text after referee's comment
EXACT: EXercise or Advice after ankle fraCTure. Design of a randomised controlled trial
<p>Abstract</p> <p>Background</p> <p>Ankle fractures are common. Management of ankle fractures generally involves a period of immobilisation followed by rehabilitation to reduce pain, stiffness, weakness and swelling. The effects of a rehabilitation program are still unclear. However, it has been shown that important components of rehabilitation programs may not confer additional benefits over exercise alone. The primary aim of this trial is to determine the effectiveness and cost-effectiveness of an exercise-based rehabilitation program after ankle fracture, compared to advice alone.</p> <p>Methods/Design</p> <p>A pragmatic randomised trial will be conducted. Participants will be 342 adults with stiff, painful ankles after ankle fracture treated with immobilisation. They will be randomly allocated using a concealed randomisation procedure to either an <it>Advice </it>or <it>Rehabilitation </it>group. Participants in the <it>Advice </it>group will receive verbal and written advice about exercise at the time of removal of immobilisation. Participants in the <it>Rehabilitation </it>group will be provided with a 4-week rehabilitation program that is designed, monitored and progressed by a physiotherapist, in addition to verbal and written advice. Outcomes will be measured by a blinded assessor at 1, 3 and 6 months. The primary outcomes will be activity limitation and quality-adjusted life years.</p> <p>Discussion</p> <p>This pragmatic trial will determine if a rehabilitation program reduces activity limitation and improves quality of life, compared to advice alone, after immobilisation for ankle fracture.</p
Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment
We have measured parity-violating asymmetries in elastic electron-proton
scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These
asymmetries, arising from interference of the electromagnetic and neutral weak
interactions, are sensitive to strange quark contributions to the currents of
the proton. The measurements were made at JLab using a toroidal spectrometer to
detect the recoiling protons from a liquid hydrogen target. The results
indicate non-zero, Q^2 dependent, strange quark contributions and provide new
information beyond that obtained in previous experiments.Comment: 5 pages, 2 figure
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