569 research outputs found
Naval History by Conspiracy Theory: The British Admiralty before the First World War and the Methodology of Revisionism
Revisionist interpretations of British naval policy in the Fisher era claim that an elaborate smoke screen was created to hide the Royal Navy’s real policies; while documents showing the true goals were systematically destroyed. By asserting this, revisionists are able to dismiss those parts of the documentary record that contradict their theories, while simultaneously excusing the lack of evidence for their theories by claiming it has been destroyed. This article shows that this methodology is misleading and untenable
Quantum capacitance and charge sensing of a superconducting double dot
We acknowledge the support from Hitachi Cambridge Laboratory and EPSRC Grant No. EP/K027018/1. A.J.F. is supported by a Hitachi Research fellowship.We study the energetics of a superconducting double dot, by measuring both the quantum capacitance of the device and the response of a nearby charge sensor. We observe different behaviour for odd and even charge states and describe this with a model based on the competition between the charging energy and the superconducting gap. We also find that, at finite temperatures, thermodynamic considerations have a significant effect on the charge stability diagram.PostprintPeer reviewe
Exploring the Structures and Substructures of the Andromeda Satellite Dwarf Galaxies Cassiopeia III, Perseus I, and Lacerta I
We present results from wide-field imaging of the resolved stellar
populations of the dwarf spheroidal galaxies Cassiopeia III (And XXXII) and
Perseus I (And XXXIII), two satellites in the outer stellar halo of the
Andromeda galaxy (M31). Our WIYN pODI photometry traces the red giant star
population in each galaxy to ~2.5-3 half-light radii from the galaxy center. We
use the Tip of the Red Giant Branch (TRGB) method to derive distances of
(m-M)_0 = 24.62+/-0.12 mag (839 (+48,-450) kpc, or 156 (+16,-13) kpc from M31)
for Cas III and 24.47+/-0.13 mag (738 (+48,-45) kpc, or 351 (+17,-16) kpc from
M31) for Per I. These values are consistent within the errors with TRGB
distances derived from a deeper Hubble Space Telescope study of the galaxies'
inner regions. For each galaxy, we derive structural parameters, total
magnitude, and central surface brightness. We also place upper limits on the
ratio of neutral hydrogen gas mass to optical luminosity, confirming the
gas-poor nature of both galaxies. We combine our data set with corresponding
data for the M31 satellite galaxy Lacerta I (And XXXI) from earlier work, and
search for substructure within the RGB star populations of Cas III, Per I, and
Lac I. We find an overdense region on the west side of Lac I at a significance
level of 2.5-3-sigma and a low-significance filament extending in the direction
of M31. In Cas III, we identify two modestly significant overdensities near the
center of the galaxy and another at two half-light radii. Per I shows no
evidence for substructure in its RGB star population, which may reflect this
galaxy's isolated nature.Comment: 26 pages, 15 figures, 5 tables. Accepted for publication in The
Astronomical Journa
Multidisciplinary teams, and parents, negotiating common ground in shared-care of children with long-term conditions: A mixed methods study
Background: Limited negotiation around care decisions is believed to undermine collaborative working between parents of children with long-term conditions and professionals, but there is little evidence of how they actually negotiate their respective roles. Using chronic kidney disease as an exemplar this paper reports on a multi-method study of social interaction between multidisciplinary teams and parents as they shared clinical care. Methods. Phases 1 and 2: a telephone survey mapping multidisciplinary teams' parent-educative activities, and qualitative interviews with 112 professionals (Clinical-psychologists, Dietitians, Doctors, Nurses, Play-specialists, Pharmacists, Therapists and Social-workers) exploring their accounts of parent-teaching in the 12 British children's kidney units. Phase 3: six ethnographic case studies in two units involving observations of professional/parent interactions during shared-care, and individual interviews. We used an analytical framework based on concepts drawn from Communities of Practice and Activity Theory. Results: Professionals spoke of the challenge of explaining to each other how they are aware of parents' understanding of clinical knowledge, and described three patterns of parent-educative activity that were common across MDTs: Engaging parents in shared practice; Knowledge exchange and role negotiation, and Promoting common ground. Over time, professionals had developed a shared repertoire of tools to support their negotiations with parents that helped them accomplish common ground during the practice of shared-care. We observed mutual engagement between professionals and parents where a common understanding of the joint enterprise of clinical caring was negotiated. Conclusions: For professionals, making implicit knowledge explicit is important as it can provide them with a language through which to articulate more clearly to each other what is the basis of their intuition-based hunches about parents' support needs, and may help them to negotiate with parents and accelerate parents' learning about shared caring. Our methodology and results are potentially transferrable to shared management of other conditions. © 2013 Swallow et al.; licensee BioMed Central Ltd
Prevalence of unrecognised myocardial infarction in a low-intermediate risk asymptomatic cohort and its relation to systemic atherosclerosis
The study was funded by the Souter Charitable Foundation and the Chest, Heart and Stroke Scotland Charity. J.R.W.M. is supported by the Wellcome Trust through the Scottish Translational Medicine and Therapeutics Initiative (grant no. WT 085664) in the form of a clinical research fellowship.Aims : Unrecognized myocardial infarctions (UMIs) have been described in 19-30% of the general population using late gadolinium enhancement (LGE) on cardiac magnetic resonance. However, these studies have focused on an unselected cohort including those with known cardiovascular disease (CVD). The aim of the current study was to ascertain the prevalence of UMIs in a non-high-risk population using magnetic resonance imaging (MRI). Methods and Results : A total of 5000 volunteers aged >40 years with no history of CVD and a 10-year risk of CVD of <20%, as assessed by the ATP-III risk score, were recruited to the Tayside Screening for Cardiac Events study. Those with a B-type natriuretic peptide (BNP) level greater than their gender-specific median were invited for a whole-body MR angiogram and cardiac MR including LGE assessment. LGE was classed as absent, UMI, or non-specific. A total of 1529 volunteers completed the imaging study; of these, 53 (3.6%) were excluded because of either missing data or inadequate LGE image quality. Ten of the remaining 1476 (0.67%) displayed LGE. Of these, three (0.2%) were consistent with UMI, whereas seven were non-specific occurring in the mid-myocardium (n = 4), epicardium (n = 1), or right ventricular insertion points (n = 2). Those with UMI had a significantly higher BNP [median 116 (range 31-133) vs. 22.6 (5-175) pg/mL, P = 0.015], lower ejection fraction [54.6 (36-62) vs. 68.9 (38-89)%, P = 0.007], and larger end-systolic volume [36.3 (27-61) vs. 21.7 (5-65) mL/m(2), P = 0.014]. Those with non-specific LGE had lower diastolic blood pressure [68 (54-70) vs. 72 (46-98) mmHg, P = 0.013] but no differences in their cardiac function. Conclusion : Despite previous reports describing high prevalence of UMI in older populations, in a predominantly middle-aged cohort, those who are of intermediate or low cardiovascular risk have a very low risk of having an unrecognized myocardial infarct.Publisher PDFPeer reviewe
Assessing methods for dealing with treatment switching in clinical trials: A follow-up simulation study
When patients randomised to the control group of a randomised controlled trial are allowed to switch onto the
experimental treatment, intention-to-treat analyses of the treatment effect are confounded because the separation of
randomised groups is lost. Previous research has investigated statistical methods that aim to estimate the treatment
effect that would have been observed had this treatment switching not occurred and has demonstrated their
performance in a limited set of scenarios. Here, we investigate these methods in a new range of realistic scenarios,
allowing conclusions to be made based upon a broader evidence base. We simulated randomised controlled
trials incorporating prognosis-related treatment switching and investigated the impact of sample size, reduced
switching proportions, disease severity, and alternative data-generating models on the performance of adjustment
methods, assessed through a comparison of bias, mean squared error, and coverage, related to the estimation of true
restricted mean survival in the absence of switching in the control group. Rank preserving structural failure time models,
inverse probability of censoring weights, and two-stage methods consistently produced less bias than the intentionto-treat
analysis. The switching proportion was confirmed to be a key determinant of bias: sample size and censoring
proportion were relatively less important. It is critical to determine the size of the treatment effect in terms of an
acceleration factor (rather than a hazard ratio) to provide information on the likely bias associated with rank-preserving
structural failure time model adjustments. In general, inverse probability of censoring weight methods are more volatile
than other adjustment methods
Left Ventricular Noncompaction:Anatomical Phenotype or Distinct Cardiomyopathy?
The present study was funded by the Souter Charitable Foundation and the Chest, Heart and Stroke Scotland Charity. Dr. Weir-McCall is supported by the Wellcome Trust through the Scottish Translational Medicine and Therapeutics Initiative (Grant no. WT 085664) in the form of a Clinical Research Fellowship.Background: There is considerable overlap between left ventricular noncompaction (LVNC) and other cardiomyopathies. LVNC has been reported in up to 40% of the general population, raising questions about whether it is a distinct pathological entity, a remodeling epiphenomenon, or merely an anatomical phenotype. Objectives: The authors determined the prevalence and predictors of LVNC in a healthy population using 4 cardiac magnetic resonance imaging diagnostic criteria. Methods: Volunteers >40 years of age (N = 1,651) with no history of cardiovascular disease (CVD), a 10-year risk of CVD < 20%, and a B-type natriuretic peptide level greater than their gender-specific median underwent magnetic resonance imaging scan as part of the TASCFORCE (Tayside Screening for Cardiac Events) study. LVNC ratios were measured on the horizontal and vertical long axis cine sequences. All individuals with a noncompaction ratio of ≥2 underwent short axis systolic and diastolic LVNC ratio measurements, and quantification of noncompacted and compacted myocardial mass ratios. Those who met all 4 criteria were considered to have LVNC. Results: Of 1,480 participants analyzed, 219 (14.8%) met ≥1 diagnostic criterion for LVNC, 117 (7.9%) met 2 criteria, 63 (4.3%) met 3 criteria, and 19 (1.3%) met all 4 diagnostic criteria. There was no difference in demographic or allometric measures between those with and without LVNC. Long axis noncompaction ratios were the least specific, with current diagnostic criteria positive in 219 (14.8%), whereas the noncompacted to compacted myocardial mass ratio was the most specific, only being met in 61 (4.4%). Conclusions: A significant proportion of an asymptomatic population free from CVD satisfy all currently used cardiac magnetic resonance imaging diagnostic criteria for LVNC, suggesting that those criteria have poor specificity for LVNC, or that LVNC is an anatomical phenotype rather than a distinct cardiomyopathy.Publisher PDFPeer reviewe
The Feasibility and Utility of Harnessing Digital Health to Understand Clinical Trajectories in Medication Treatment for Opioid Use Disorder: D-TECT Study Design and Methodological Considerations
Introduction: Across the U.S., the prevalence of opioid use disorder (OUD) and the rates of opioid overdoses have risen precipitously in recent years. Several effective medications for OUD (MOUD) exist and have been shown to be life-saving. A large volume of research has identified a confluence of factors that predict attrition and continued substance use during substance use disorder treatment. However, much of this literature has examined a small set of potential moderators or mediators of outcomes in MOUD treatment and may lead to over-simplified accounts of treatment non-adherence. Digital health methodologies offer great promise for capturing intensive, longitudinal ecologically-valid data from individuals in MOUD treatment to extend our understanding of factors that impact treatment engagement and outcomes.
Methods: This paper describes the protocol (including the study design and methodological considerations) from a novel study supported by the National Drug Abuse Treatment Clinical Trials Network at the National Institute on Drug Abuse (NIDA). This study (D-TECT) primarily seeks to evaluate the feasibility of collecting ecological momentary assessment (EMA), smartphone and smartwatch sensor data, and social media data among patients in outpatient MOUD treatment. It secondarily seeks to examine the utility of EMA, digital sensing, and social media data (separately and compared to one another) in predicting MOUD treatment retention, opioid use events, and medication adherence [as captured in electronic health records (EHR) and EMA data]. To our knowledge, this is the first project to include all three sources of digitally derived data (EMA, digital sensing, and social media) in understanding the clinical trajectories of patients in MOUD treatment. These multiple data streams will allow us to understand the relative and combined utility of collecting digital data from these diverse data sources. The inclusion of EHR data allows us to focus on the utility of digital health data in predicting objectively measured clinical outcomes.
Discussion: Results may be useful in elucidating novel relations between digital data sources and OUD treatment outcomes. It may also inform approaches to enhancing outcomes measurement in clinical trials by allowing for the assessment of dynamic interactions between individuals\u27 daily lives and their MOUD treatment response.
Clinical Trial Registration: Identifier: NCT04535583
Mary Adams and the producer’s role in early BBC science broadcasts
Mary Adams was a science producer at the BBC from 1930–6. She is shown to have played a crucial role in shaping science broadcasts, in particular devising formats and styles of presentation. However, her approach is shown to have been primarily motivated by broadcasting considerations rather than by the popularisation of science. Through her interaction with scientists she helped to construct a new professional domain, that of the science-broadcasting professional, at a time when other producers were creating analogous roles in other areas of broadcasting. This paper is based largely on unpublished archival documents
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The global diet and activity research (GDAR) network: a global public health partnership to address upstream NCD risk factors in urban low and middle-income contexts.
BACKGROUND: Non-communicable diseases (NCDs) are the leading cause of death globally. While upstream approaches to tackle NCD risk factors of poor quality diets and physical inactivity have been trialled in high income countries (HICs), there is little evidence from low and middle-income countries (LMICs) that bear a disproportionate NCD burden. Sub-Saharan Africa and the Caribbean are therefore the focus regions for a novel global health partnership to address upstream determinants of NCDs. PARTNERSHIP: The Global Diet and Activity research Network (GDAR Network) was formed in July 2017 with funding from the UK National Institute for Health Research (NIHR) Global Health Research Units and Groups Programme. We describe the GDAR Network as a case example and a potential model for research generation and capacity strengthening for others committed to addressing the upstream determinants of NCDs in LMICs. We highlight the dual equity targets of research generation and capacity strengthening in the description of the four work packages. The work packages focus on learning from the past through identifying evidence and policy gaps and priorities, understanding the present through adolescent lived experiences of healthy eating and physical activity, and co-designing future interventions with non-academic stakeholders. CONCLUSION: We present five lessons learned to date from the GDAR Network activities that can benefit other global health research partnerships. We close with a summary of the GDAR Network contribution to cultivating sustainable capacity strengthening and cutting-edge policy-relevant research as a beacon to exemplify the need for such collaborative groups
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