3,406 research outputs found

    Equilibrium states for potentials with \sup\phi - \inf\phi < \htop(f)

    Full text link
    In the context of smooth interval maps, we study an inducing scheme approach to prove existence and uniqueness of equilibrium states for potentials ϕ\phi with he `bounded range' condition \sup \phi - \inf \phi < \htop, first used by Hofbauer and Keller. We compare our results to Hofbauer and Keller's use of Perron-Frobenius operators. We demonstrate that this `bounded range' condition on the potential is important even if the potential is H\"older continuous. We also prove analyticity of the pressure in this context.Comment: Added Lemma 6 to deal with the disparity between leading eigenvalues and operator norms. Added extra references and corrected some typo

    Checklists improve experts' diagnostic decisions

    Get PDF
    Context Checklists are commonly proposed tools to reduce error. However, when applied by experts, checklists have the potential to increase cognitive load and result in expertise reversal'. One potential solution is to use checklists in the verification stage, rather than in the initial interpretation stage of diagnostic decisions. This may avoid expertise reversal by preserving the experts' initial approach. Whether checklist use during the verification stage of diagnostic decision making improves experts' diagnostic decisions is unknown. Methods Fifteen experts interpreted 18 electrocardiograms (ECGs) in four different conditions: undirected interpretation; verification without a checklist; verification with a checklist, and interpretation combined with verification with a checklist. Outcomes included the number of errors, cognitive load, interpretation time and interpretation length. Outcomes were compared in two analyses: (i) a comparison of verification conditions with and without a checklist, and (ii) a comparison of all four conditions. Standardised scores for each outcome were used to calculate the efficiency of a checklist and to weigh its relative benefit against its relative cost in terms of cognitive load imposed, interpretation time and interpretation length. Results In both analyses, checklist use was found to reduce error (more errors were corrected in verification conditions with checklists [0.29 +/- 0.77 versus 0.03 +/- 0.61 errors per ECG], and fewer net errors occurred in all conditions with checklists [0.39 +/- 1.14 versus 1.04 +/- 1.49 errors per ECG];

    Independent sets of interpolation nodes or "how to make all sets regular"

    Get PDF
    Hermite-Birkhoff interpolation and Pál-type interpolation have been receiving much attention over the years. Also during the previous 15 years the subject of interpolation in non-uniformly distributed nodes has been looked into. There are, however, not many examples known where lacunary problems (the orders of the derivatives for which data are given, are non-consecutive) are regular. Here lacunary Pál-type interpolation is looked into "the other way around": the interpolation points are given and the orders of the derivatives to be used are derived from the number of points.

    SELF-DIFFUSION OF BERYLLIUM IN UNIRRADIATED, COLD-PRESSED AND SINTERED BERYLLIUM OXIDE

    Get PDF
    Diffusion of beryllium-7 through polycrystalline unirradiated specimens of BeO was studied as a preliminary step to a study of diffusion in irradiated material. Beryllium-7 was deposited on one end of cylindrical specimens by exchange and adsorption from aqueous solution. The depth of penetration perpendicular to the surfaces of deposition was determined after annealing the specimens at pre-determined conditions. A simple lapping device of high precision was developed to determine penetration depths. For the polycrystalline cold-pressed and sintered BeO studied, the diffusion behavior between 1150 and 1800 deg C is described by the empirical relation: D = 2.49 x 10/sup -3/ exp -- (62.5 x 10/sup 3//RT) cm/sup 2//sec. A diffusion model is proposed based on vacancy migration which suggests identical activation energies for diffusion in both a and c directions in single crystals and predicts an activation energy of the correct order oi magnitude. Furthermore, the model p dicts that the frequency factor in the direction pexpendicular to the c axis should be about 50% higher than that parallel to the c axis. (auth

    Safety risks among frail older people living at home in the Netherlands:A cross‐sectional study in a routine primary care sample

    Get PDF
    Frail older people face a range of problems and risks that could undermine their ability to live safely at home. A comprehensive overview of these risks, from a multidimensional perspective, is currently lacking. This study aims to examine the prevalence of risks in multiple domains of life among frail older people living at home. We used cross‐sectional data from 824 people aged 65 years and older, who received a comprehensive geriatric assessment (the interRAI Home Care [interRAI‐HC]) between 2014 and 2018, as part of routine care from 25 general practices in the region of West‐Friesland, the Netherlands. The interRAI‐HC identifies amenable risks related to people's clinical conditions, functioning, lifestyle and behaviour, and social and physical environment. Descriptive statistics were used to examine population characteristics (age, gender, marital status, living arrangements and presence of chronic conditions) and prevalence of risks. Most common risks were related to people's clinical conditions (i.e cardio‐respiratory health, urinary incontinence, pain), functioning (i.e. limitations in instrumental activities of daily living and mood) and social environment (i.e. limitations in informal care and social functioning). More than 80% of frail older people faced multiple risks, and often on multiple domains of life simultaneously. People experiencing multiple risks per person, and on multiple domains simultaneously, were more often widowed and living alone. The multidimensional character of risks among frail older people living at home implies that an integrated approach to care, comprising both health and social care, is necessary. Insight in the prevalence of these risks can give direction to care allocation decisions

    Do you have to re-examine to reconsider your diagnosis? Checklists and cardiac exam

    Get PDF
    Background Few studies have investigated whether clinicians can use checklists to verify their diagnostic decisions. Checklists may improve accuracy by prompting clinicians to reconsider or recollect information but might impair decision making by adding to clinicians' cognitive load. This study assessed whether checklists improve cardiac exam diagnostic accuracy, and whether this benefit is dependent on collecting additional information. Methods 191 internal medicine residents examined a cardiopulmonary simulator. They provided a diagnosis, subjective rating of certainty, and key findings before and after using a checklist. Residents were randomised; half were allowed access to the simulator and half were prohibited access to the simulator while using the checklist. Residents rated their cognitive load in each step: prechecklist diagnosis, checklist use and postchecklist diagnosis. Result Verifying with a checklist resulted in improved diagnostic accuracy; 88 residents (46%) made the correct diagnosis before using the checklist compared with 97 (51%) afterwards, p=0.04. The benefit of checklist use was restricted to residents allowed to re-examine the simulator (10 changed to correct diagnosis and one to an incorrect diagnosis) whereas no net benefit was seen among residents unable to re-examine the simulator (two changed to a correct diagnosis and two to an incorrect diagnosis, p=0.03). Those able to re-examine the simulator were slightly more confident after checklist use, whereas those unable to re-examine were slightly less confident after checklist use (p=0.01). The opportunity to re-examine the simulator had no effect on the accuracy of key findings reported. Of the three steps, checklist use was associated with the lowest cognitive load (F-1,F-189=68
    corecore