919 research outputs found

    Discursive design thinking: the role of explicit knowledge in creative architectural design reasoning

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    The main hypothesis investigated in this paper is based upon the suggestion that the discursive reasoning in architecture supported by an explicit knowledge of spatial configurations can enhance both design productivity and the intelligibility of design solutions. The study consists of an examination of an architect’s performance while solving intuitively a well-defined problem followed by an analysis of the spatial structure of their design solutions. One group of architects will attempt to solve the design problem logically, rationalizing their design decisions by implementing their explicit knowledge of spatial configurations. The other group will use an implicit form of such knowledge arising from their architectural education to reason about their design acts. An integrated model of protocol analysis combining linkography and macroscopic coding is used to analyze the design processes. The resulting design outcomes will be evaluated quantitatively in terms of their spatial configurations. The analysis appears to show that an explicit knowledge of the rules of spatial configurations, as possessed by the first group of architects can partially enhance their function-driven judgment producing permeable and well-structured spaces. These findings are particularly significant as they imply that an explicit rather than an implicit knowledge of the fundamental rules that make a layout possible can lead to a considerable improvement in both the design process and product. This suggests that by externalizing th

    General Practitioners’ views of blood pressure control in people with and without dementia

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    Introduction: Since 2012, our group has undertaken a programme of research examining the treatment of hypertension in people with dementia. Hypertension is managed by GPs, who are guided by NICE guidelines, which make no mention of different management in people with dementia. We sought to explore the views of GPs on whether they manage hypertension differently in people with dementia. Method: We chose to try using an on-online survey to seek views, with both open and closed questions. We offered vignettes describing 71 and 83 year old women without cognitive impairment or with dementia, and a free text box – comments provided in this box were analysed thematically. Results: Although 427 GPs responded to the questionnaire, this was only 7% of all GPs eligible. Responding GPs were twice as likely not to offer treatment to the patient aged 71 with dementia and a BP above 140/90 (NICE threshold) compared to one without dementia (23.9% vs 11.7%). A similar finding was found when the vignettes involving 83 year old women with and without dementia (using 160/100, the NICE threshold for this age group) where 7.3% would not offer treatment in the woman with dementia compared to 3.3% in those without dementia. The analysis of free text identified four major themes, which were labelled as ‘complex decisions, ‘blood pressure measurement‘, ‘uncertainties around treatment’ and ‘compliance with guidelines’. Discussion: The low response rate in this survey makes the findings potentially unreliable, and other methods of ascertaining GP views, intentions or practices should be considered. Despite this, the findings from this study, in particular the free text comments indicate that the management of hypertension in people with dementia, is likely to be more complex than current guidelines indicate, and we propose that further research and clarification of best practice would be helpful

    New horizons in the implementation and research of comprehensive geriatric assessment: knowing, doing and the “know-do” gap

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    In this paper we outline the relationship between the need to put existing applied health research knowledge into practice (the “know-do gap”) and the need to improve the evidence base (the “know gap”) with respect to the health care process used for older people with frailty known as comprehensive geriatric assessment (CGA). We explore the reasons for the know-do gap and the principles of how these barriers to implementation might be overcome. We explore how these principles should affect the conduct of applied health research to close the know gap. We propose that impaired flow of knowledge is an important contributory factor in the failure to implement evidence-based practice in comprehensive geriatric assessment; this could be addressed through specific knowledge mobilisation techniques. We describe that implementation failures are also produced by an inadequate evidence base which requires the co-production of research, addressing not only effectiveness but also the feasibility and acceptability of new services, the educational needs of practitioners, the organisational requirements of services, and the contribution made by policy. Only by tackling these issues in concert and appropriate proportion, will the know and know-do gaps for CGA be closed

    Preparatory review of studies of withdrawal of anti-hypertensive medication in older people

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    Introduction: Since 2012 we have undertaken a programme of research into the management of hypertension in people with dementia. As part of this we are studying the feasibility of withdrawing antihypertensive drugs in people with dementia and well-controlled hypertension, with the aim of them remaining normotensive but avoiding some of the burdens and side-effects of antihypertensive medications. We decided to undertake a preliminary examination of the literature to examine the evidence and safety of antihypertensive withdrawal (not restricted to those with dementia) to determine whether this has already been extensively reviewed, to provide an approximate estimate of the likelihood of success of antihypertensive withdrawal, and to prepare for a systematic review of this literature if required and feasible. Method: For this rapid review, we undertook a search for existing reviews and examined the relevant papers identified, and briefly updated the search once we found that the most recent review was in 2008. Results: One appropriate review (from 2008) yielding seven relevant articles, and one further article were identified, giving eight articles which were examined. Seven of the eight were published more than ten years ago. Six of the eight studies had follow-up data for 1 year or longer. Successful long term (1 year or more) withdrawal of antihypertensive medication was reported in 20-52% of patients. Conclusion: Our review indicates that 22-50% of patients whose blood pressures are currently adequately controlled might be able to withdraw medication without return of long term hypertension. The rapid review approach we took may have missed articles of relevance and so we propose that a systematic review of withdrawal is undertaken. Because much of the data will be old, it should seek data not only on the proportions of patients who remained normotensive at long term follow up using the standards of the day, but should seek data on findings relevant to current guidelines. Only data reporting long term follow up (≥ 1 year) should be included. Data referring to old or discontinued medications should be distinguished

    "Galaxy," Defined

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    A growing number of low luminosity and low surface brightness astronomical objects challenge traditional notions of both galaxies and star clusters. To address this, we propose a definition of galaxy independent of the cold dark matter model of the universe: A galaxy is a gravitationally bound set of stars whose properties cannot be explained by a combination of baryons and Newton's laws of gravity. After exploring observational diagnostics of this definition, we examine the classification of ultra-faint dwarfs, globular clusters, ultra-compact dwarfs, and tidal dwarfs. While kinematic studies provide an effective galaxy diagnostic in many regimes, they can be less useful for compact or faint systems. To explore the use of [Fe/H] spread as a complementary diagnostic, we use published spectroscopic [Fe/H] measurements of 16 Milky Way dwarfs and 24 globular clusters to calculate their [Fe/H] spreads and uncertainties. Our principal results are: (i) no old star cluster less luminous then M_V = -10 has a significant (> 0.1 dex) spread in iron; (ii) known ultra-faint dwarfs can be classified with a combination of kinematics and [Fe/H]; (iii) the observed [Fe/H] spreads in massive (> 10^6 M_Sun) globular clusters do not necessarily imply they are the stripped nuclei of dwarfs, nor a need for dark matter; and (iv) if ultra-compact dwarfs reside in dark matter halos akin to those of ultra-faint dwarfs of the same half-light radii, then they will show no clear dynamical signature of dark matter. We suggest measurements that may assist future classification of massive globular clusters, ultra-compact dwarfs, and ultra-faint galaxies. Our galaxy definition is designed to be independent of the details of current observations and models, while our proposed diagnostics can be refined or replaced as our understanding of the universe evolves.Comment: Accepted by AJ; This updated version includes several new references, as well as improvements throughout the text for clarity - in particular clarifying our intended distinction between galaxy "definition" and "diagnostics

    NGC 2419 -- Another Remnant of Accretion by the Milky Way

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    We isolate a sample of 43 upper RGB stars in the extreme outer halo Galactic globular cluster NGC 2419 from two Keck/DEIMOS slitmasks. The probability that there is more than one contaminating halo field star in this sample is extremely low. Analysis of moderate resolution spectra of these cluster members, as well as of our Keck/HIRES high resolution spectra of a subsample of them, demonstrates that there is a small but real spread in Ca abundance of ~ 0.2 dex within this massive metal-poor globular cluster. This provides additional support to earlier suggestions that NGC 2419 is the remnant of a dwarf galaxy accreted long ago by the Milky Way.Comment: Accepted to the Astrophysical Journa

    The emptiness of voids: yet another over-abundance problem for the LCDM model

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    We study the luminosity function, the peculiar velocities, and the sizes of voids in the Local Volume (LV) in observational samples of galaxies which contain galaxies down to MB=-10-12 within the distance 4-8Mpc. Comparing the results with the predictions of the standard cosmological LCDM model, we find that the theory faces a sever problem: it predicts a factor of ten more dwarf haloes as compared with the observed number of dwarf galaxies. In the LV we identify voids with sizes ranging from 1 to 4.5Mpc and compare the observational distribution of void sizes with the voids in very high resolution simulations of the LCDM model with WMAP1 and WMAP3 parameters. The theoretical void function matches the observations remarkably well only if we use haloes with circular velocities Vc larger than 40-45 km/s (Mvir=(1-2)e10msun) for models with with sigma8 = 0.9 and Vc>35km/s (Mvir=(6-8)e9msun) for sigma8 = 0.75. We exclude the possibility that in the LCDM model haloes with circular velocities < 35km/s can host galaxies as bright as MB=-12: there are too many small haloes in the LCDM model resulting in voids being too small as compared with the observations. The problem is that many of the observed dwarf galaxies have HI rotational velocities below 25km/s that strictly contradicts the LCDM predictions. Thus, the LCDM model faces the same overabundance problem, which it had with the number of satellites in the LG. We also estimate the rms deviations from the Hubble flow sigmaH and find that in most of our model LV-candidates the rms peculiar velocities are consistent with observational values sigmaH=50km/s for distances less than 3Mpc and sigmaH=80km/s for distances less than 8Mpc. At distances 4 (8) Mpc, the observed overdensities of galaxies are 3.5-5.5 (1.3-1.6) -- significantly larger than typically assumed.Comment: 10 pages, accepted to MNRA

    Satellite abundances around bright isolated galaxies

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    We study satellite galaxy abundances in SDSS by counting photometric galaxies around isolated bright primaries. We present results as a function of the luminosity, stellar mass and colour of the satellites, and of the stellar mass and colour of the primaries. For massive primaries the luminosity and stellar mass functions of satellites are similar in shape to those of field galaxies, but for lower mass primaries they are significantly steeper. The steepening is particularly marked for the stellar mass function. Satellite abundance increases strongly with primary stellar mass, approximately in proportion to expected dark halo mass. Massive red primaries have up to a factor of 2 more satellites than blue ones of the same stellar mass. Satellite galaxies are systematically redder than field galaxies of the same stellar mass. Satellites are also systematically redder around more massive primaries. At fixed primary mass, they are redder around red primaries. We select similarly isolated galaxies from mock catalogues based on the simulations of Guo et al.(2011) and analyze them in parallel with the SDSS data. The simulation reproduces all the above trends qualitatively, except for the steepening of the satellite luminosity and stellar mass functions. Model satellites, however, are systematically redder than in the SDSS, particularly at low mass and around low-mass primaries. Simulated haloes of a given mass have satellite abundances that are independent of central galaxy colour, but red centrals tend to have lower stellar masses, reflecting earlier quenching of their star formation by feedback. This explains the correlation between satellite abundance and primary colour in the simulation. The correlation between satellite colour and primary colour arises because red centrals live in haloes which are more massive, older and more gas-rich, so that satellite quenching is more efficient.Comment: 29 pages, 24 figure

    Unrestricted faecal calprotectin testing performs poorly in the diagnosis of inflammatory bowel disease in patients in primary care

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    BACKGROUND: Faecal calprotectin (FC) measurement distinguishes patients with inflammatory bowel disease (IBD) from those with irritable bowel syndrome but evidence of its performance in primary care is limited. AIMS: To assess the yield of IBD from FC testing in primary care. METHODS: Retrospective review of hospital records to assess the outcome following FC testing in primary care. Investigations for all patients undergoing FC testing in a single laboratory for 6 months from 1 October 2013 to 28 February 2014 were reviewed. RESULTS: 410 patients (162 male; median age 42; range 16-91) were included. FC>50 µg/g was considered positive (FC+). 148/410 (36.1%; median age 44 (17-91)) were FC+ (median FC 116.5 µg/g (51-1770)). 122/148 FC-positive patients (82.4%) underwent further investigation. 97 (65.5%) underwent lower gastrointestinal endoscopy (LGIE), of which 7 (7.2%) had IBD. 49/262 (18.7%) FC-negative (FC-) patients (FC ≤50 µg/g) (median age 47 (19-76)) also underwent LGIE, of whom 3 (6.1%) had IBD.IBD was diagnosed in 11/410 (2.7%; 4 ulcerative colitis, 3 Crohn's disease, 4 microscopic colitis). 8/11 were FC+ (range 67-1170) and 3 FC-. At a 50 µg/g threshold, sensitivity for detecting IBD was 72.7%, specificity 64.9%, positive predictive value (PPV) 5.41% and negative predictive value 98.9%. Increasing the threshold to 100 µg/g reduced the sensitivity of the test for detecting IBD to 54.6%. CONCLUSIONS: FC testing in primary care has low sensitivity and specificity with poor PPV for diagnosing IBD. Its use needs to be directed to those with a higher pretest probability of disease. Local services and laboratories should advise general practitioners accordingly
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