2,251 research outputs found
Non-stationary dynamo & magnetospheric accretion processes of the classical T Tauri star V2129 Oph
We report here the first results of a multi-wavelength campaign focussing on
magnetospheric accretion processes of the classical TTauri star (cTTS)
V2129Oph. In this paper, we present spectropolarimetric observations collected
in 2009 July with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT).
Circularly polarised Zeeman signatures are clearly detected, both in
photospheric absorption and accretion-powered emission lines, from time-series
of which we reconstruct new maps of the magnetic field, photospheric brightness
and accretion-powered emission at the surface of V2129Oph using our newest
tomographic imaging tool - to be compared with those derived from our old 2005
June data set, reanalyzed in the exact same way.
We find that in 2009 July, V2129Oph hosts octupolar & dipolar field
components of about 2.1 & 0.9kG respectively, both tilted by about 20deg with
respect to the rotation axis; we conclude that the large-scale magnetic
topology changed significantly since 2005 June (when the octupole and dipole
components were about 1.5 and 3 times weaker respectively), demonstrating that
the field of V2129Oph is generated by a non-stationary dynamo. We also show
that V2129Oph features a dark photospheric spot and a localised area of
accretion-powered emission, both close to the main surface magnetic region
(hosting fields of up to about 4kG in 2009 July). We finally obtain that the
surface shear of V2129Oph is about half as strong as solar.
From the fluxes of accretion-powered emission lines, we estimate that the
observed average logarithmic accretion rate (in Msun/yr) at the surface of
V2129Oph is -9.2+-0.3 at both epochs, peaking at -9.0 at magnetic maximum. It
implies in particular that the radius at which the magnetic field of V2129Oph
truncates the inner accretion disc is 0.93x and 0.50x the corotation radius in
2009 July and 2005 June respectively.Comment: MNRAS in press - 16 pages, 9 figure
Symptom Signatures and Diagnostic Timeliness in Cancer Patients: A Review of Current Evidence
Early diagnosis is an important aspect of contemporary cancer prevention and control strategies, as the majority of patients are diagnosed following symptomatic presentation. The nature of presenting symptoms can critically influence the length of the diagnostic intervals from symptom onset to presentation (the patient interval), and from first presentation to specialist referral (the primary care interval). Understanding which symptoms are associated with longer diagnostic intervals to help the targeting of early diagnosis initiatives is an area of emerging research. In this Review, we consider the methodological challenges in studying the presenting symptoms and intervals to diagnosis of cancer patients, and summarize current evidence on presenting symptoms associated with a range of common and rarer cancer sites. We propose a taxonomy of cancer sites considering their symptom signature and the predictive value of common presenting symptoms. Finally, we consider evidence on associations between symptomatic presentations and intervals to diagnosis before discussing implications for the design, implementation, and evaluation of public health or health system interventions to achieve the earlier detection of cancer
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Dermoscopy use in UK primary care: a survey of GPs with a special interest in dermatology.
BACKGROUND: Melanoma accounts for 90% of skin cancer mortality and typically presents in primary care, where it can be challenging to distinguish from benign lesions. Dermoscopy is a tool for skin visualization that is routinely used for melanoma diagnosis in secondary care. However, the role of dermoscopy in primary care remains unclear. OBJECTIVES: To determine views on, and use of, dermoscopy by dermatology-interested general practitioners (GPs). METHODS: An online questionnaire was emailed to the UK Primary Care Dermatology Society members in February 2018, and responses collected over the following 4 weeks. RESULTS: A total of 205 responses were analysed. Most respondents were GPs (94%), aged over 50 (53%), had a postgraduate dermatological qualification (67%) and used dermoscopy regularly when reviewing pigmented skin lesions (97%). Dermoscopy use was commoner amongst GPs who had worked longer in primary care and had experience of secondary care dermatology. Most had undertaken training in dermoscopy (91%), although one-fifth (20%) had not updated their training in over 5 years. Most of those who had received only 1 day of face-to-face training reported feeling confident using a dermatoscope. Few respondents (11%) reported access to teledermatology or teledermoscopy for urgent or routine referrals. CONCLUSIONS: UK GPs with a special interest in dermatology are routinely using dermoscopy in the primary care setting. More research is needed to establish optimal approaches to training and updating GP dermoscopy skills. When dermoscopy has been shown to be safe, effective, acceptable and cost-effective in this setting, more GPs may also be able to gain and maintain the skills to implement dermoscopy into routine primary care. Technological advances, including incorporation of artificial intelligence (AI) and algorithms to guide GPs, could also contribute to widening use of dermoscopy among GPs
Can we do better? A qualitative study in the East of England investigating patient experience and acceptability of using the faecal immunochemical test in primary care.
OBJECTIVES: The faecal immunochemical test (FIT) is increasingly used in UK primary care to triage patients presenting with symptoms and at different levels of colorectal cancer risk. Evidence is scarce on patients' views of using FIT in this context. We aimed to explore patients' care experience and acceptability of using FIT in primary care. DESIGN: A qualitative semi-structured interview study. Interviews were conducted via Zoom between April and October 2020. Transcribed recordings were analysed using framework analysis. SETTING: East of England general practices. PARTICIPANTS: Consenting patients (aged ≥40 years) who presented in primary care with possible symptoms of colorectal cancer, and for whom a FIT was requested, were recruited to the FIT-East study. Participants were purposively sampled for this qualitative substudy based on age, gender and FIT result. RESULTS: 44 participants were interviewed with a mean age 61 years, and 25 (57%) being men: 8 (18%) received a positive FIT result. Three themes and seven subthemes were identified. Participants' familiarity with similar tests and perceived risk of cancer influenced test experience and acceptability. All participants were happy to do the FIT themselves and to recommend it to others. Most participants reported that the test was straightforward, although some considered it may be a challenge to others. However, test explanation by healthcare professionals was often limited. Furthermore, while some participants received their results quickly, many did not receive them at all with the common assumption that 'no news is good news'. For those with a negative result and persisting symptoms, there was uncertainty about any next steps. CONCLUSIONS: While FIT is acceptable to patients, elements of communication with patients by the healthcare system show potential for improvement. We suggest possible ways to improve the FIT experience, particularly regarding communication about the test and its results
Assessing architectural evolution: A case study
This is the post-print version of the Article. The official published can be accessed from the link below - Copyright @ 2011 SpringerThis paper proposes to use a historical perspective on generic laws, principles,
and guidelines, like Lehman’s software evolution laws and Martin’s design principles, in order to achieve a multi-faceted process and structural assessment of a system’s architectural evolution. We present a simple structural model with associated historical metrics and
visualizations that could form part of an architect’s dashboard. We perform such an assessment for the Eclipse SDK, as a case study of a large, complex, and long-lived system for which sustained effective architectural evolution is paramount. The twofold aim of checking generic principles on a well-know system is, on the one hand,
to see whether there are certain lessons that could be learned for best practice of architectural evolution, and on the other hand to get more insights about the applicability of such principles. We find that while the Eclipse SDK does follow several of the laws and principles, there are some deviations, and we discuss areas of architectural improvement and limitations of the assessment approach
The role of literacy in the association between educational attainment and depressive symptoms
There is a consistent association between education and depressive symptoms, but research on the mechanisms to explain this association remains limited. No study has formally evaluated the extent to which the association between education and depressive symptoms is mediated through a foundational skill such as literacy. Inverse odds ratio weighting (IORW) was used to estimate total, natural direct, and natural indirect effects in examining literacy as a mediator of the association between education and depressive symptoms. Health and Retirement Study participants born in the U.S. between 1900 and 1947 were interviewed biennially for up to 12 years (N = 16,718). Literacy was assessed with a brief vocabulary measure. Depressive symptoms were measured using the 8-item Centers for Epidemiologic Studies-Depression (CES-D) scale. Decomposition estimates were derived using regression analyses of repeated measures of depressive symptoms. Standard errors were obtained using a nonparametric bootstrap with the individual as the independent unit to account for dependence of observations within an individual. In a large cohort of older Americans, a one standard deviation difference in educational attainment (~ 3 years) was associated with a 0.35-point decrement in CES-D score (95% CI: -0.38, -0.32). This decrement represents a 0.22 standard deviation difference in depressive symptoms. Using IORW, the estimated effect of education on depressive symptoms mediated through literacy was -0.10 (95% CI: -0.18, -0.01), which represents 28% of the total effect. Education confers many benefits; as demonstrated by this study for depressive symptoms, one important benefit is literacy
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