3,801 research outputs found

    Do clinicians overestimate the severity of intracerebral hemorrhage?

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    Background and Purpose— Intracerebral hemorrhage (ICH) has a poorer prognosis than acute ischemic stroke (AIS). However, clinician perception of prognosis may influence treatment decisions and adversely affect outcome. On acute CT, the conspicuity of ICH compared with AIS may lead clinicians to overestimate severity and influence prognostic evaluation. We investigated whether clinicians’ estimates of volume, severity, and prognosis from acute imaging differed between ICH and AIS. Methods— CT scans from participants with acute ICH or ischemic stroke were reviewed. Volume was calculated using the ABC/2 method and automated volumetric analysis via specialized imaging software. ICH cases were matched with AIS cases for lesion volume, based on acute (<6 hours) CT for ICH, and 24-hour CT for AIS. Blind to clinical information, clinicians estimated lesion volume to the nearest 5 mL, graded lesion severity from 1 (mild) to 5 (very severe), and estimated 30-day prognosis using the modified Rankin Scale. Results— We compared 33 ICH cases with 33 volume-matched AIS cases. Clinicians overestimated ICH volume and underestimated AIS volumes: mean differences (estimated−actual volume) were +8 mL (±30) for ICH and −8 mL (±27) for AIS (P<0.001). Observers rated ICH to be of greater severity and poorer prognosis compared with AIS cases: 109 of 265 (41%) ICH cases rated severity categories 4 or 5 compared with 36 of 257 (14%) AIS, P<0.001; estimated modified Rankin Scale of 0 to 2 in 125 of 265 (47%) ICH compared with 190 of 257 (74%) AIS, P<0.001. Results were unaffected by presence of intraventricular blood. Estimated severity and prognosis for ICH remained significantly worse compared with AIS after adjustment for estimated volumes. Conclusions— Clinicians overestimated ICH volume and severity compared with AIS of equivalent volume and also assigned significantly worse prognosis independent of volume estimates

    The role of parental achievement goals in predicting autonomy-supportive and controlling parenting

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    Although autonomy-supportive and controlling parenting are linked to numerous positive and negative child outcomes respectively, fewer studies have focused on their determinants. Drawing on achievement goal theory and self-determination theory, we propose that parental achievement goals (i.e., achievement goals that parents have for their children) can be mastery, performance-approach or performance-avoidance oriented and that types of goals predict mothers' tendency to adopt autonomy-supportive and controlling behaviors. A total of 67 mothers (aged 30-53 years) reported their goals for their adolescent (aged 13-16 years; 19.4 % girls), while their adolescent evaluated their mothers' behaviors. Hierarchical regression analyses showed that parental performance-approach goals predict more controlling parenting and prevent acknowledgement of feelings, one autonomy-supportive behavior. In addition, mothers who have mastery goals and who endorse performance-avoidance goals are less likely to use guilt-inducing criticisms. These findings were observed while controlling for the effect of maternal anxiety

    Analyzing white dwarf + white dwarf binaries with Gaia trigonometric parallaxes

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    White dwarfs (WDs) have been used as chronometers to age date the solar neighborhood, open clusters, globular clusters, and even the Galactic halo field population. The availability of highly accurate and precise Gaia trigonometric parallaxes along with nearly all-sky, homogenous photometric surveys (SDSS, Pan-STARRS) now allows us to improve the precision in WD ages. We report on the consistency of ages among seven WD+WD binaries, run through BASE-9 individually and in pairs. BASE-9 uses Bayesian analysis to estimate the values for stellar parameters, such as age, distance, and metallicity. We found that using Gaia\u27s parallaxes with binary systems constrains the errors in these estimations, by lowering uncertainties and constraining the ages and distances of the systems

    Improving White Dwarfs as Chronometers with Gaia Parallaxes and Spectroscopic Metallicities

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    White dwarfs (WDs) offer unrealized potential in solving two problems in astrophysics: stellar age accuracy and precision. WD cooling ages can be inferred from surface temperatures and radii, which can be constrained with precision by high-quality photometry and parallaxes. Accurate and precise Gaia parallaxes along with photometric surveys provide information to derive cooling and total ages for vast numbers of WDs. Here we analyze 1372 WDs found in wide binaries with main-sequence (MS) companions and report on the cooling and total age precision attainable in these WD+MS systems. The total age of a WD can be further constrained if its original metallicity is known because the MS lifetime depends on metallicity at fixed mass, yet metallicity is unavailable via spectroscopy of the WD. We show that incorporating spectroscopic metallicity constraints from 38 wide binary MS companions substantially decreases internal uncertainties in WD total ages compared to a uniform constraint. Averaged over the 38 stars in our sample, the total (internal) age uncertainty improves from 21.04% to 16.77% when incorporating the spectroscopic constraint. Higher mass WDs yield better total age precision; for eight WDs with zero-age MS masses \u3e= 2.0 M, the mean uncertainty in total ages improves from 8.61% to 4.54% when incorporating spectroscopic metallicities. We find that it is often possible to achieve 5% total age precision for WDs with progenitor masses above 2.0 M if parallaxes wit

    Is the Health and Wellbeing of University Students Associated with their Academic Performance? Cross Sectional Findings from the United Kingdom

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    This study explored the associations between health awareness, health behaviour, subjective health status, and satisfaction of students with their educational experience as independent variables and three outcomes of educational achievement as dependent variables. We undertook two simultaneous cross-sectional surveys among students from one University in the UK during 2008−2009. The first survey was a general health survey; the second survey measured students’ satisfaction with different aspects of their learning and teaching experience. Students’ registration numbers linked the responses of both questionnaires together, and subsequently linked the questionnaires to the university database to import the grades that students actually achieved in their studies. Generally, on average, students (N = 380) exhibited medium to high satisfaction with their educational experiences. In the multivariate regression analyses, students’ satisfaction with their educational experiences was not associated with any of the three indicators of educational achievement (actual module mark; perceived own performance; importance of achieving good grades). The associations of educational satisfaction, health, health behaviours, heath complaints and financial parameters with the three outcomes of educational achievement did not differ between male and female students. Each of the health, health behaviours, health complaints and financial parameters were selectively associated with only some but not all three indicators of student educational achievement. We conclude that the findings support a conceptual framework suggesting reciprocal relationships between health, health behaviour and educational achievement. Comprehensive health promotion programmes may have the potential to influence relevant predictors of educational achievement in university students

    Quantifying T2 relaxation time changes within lesions defined by apparent diffusion coefficient in grey and white matter in acute stroke patients

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    The apparent diffusion coefficient (ADC) of cerebral water, as measured by diffusion MRI, rapidly decreases in ischaemia, highlighting a lesion in acute stroke patients. The MRI T 2 relaxation time changes in ischaemic brain such that T 2 in ADC lesions may be informative of the extent of tissue damage, potentially aiding in stratification for treatment. We have developed a novel user-unbiased method of determining the changes in T 2 in ADC lesions as a function of clinical symptom duration based on voxel-wise referencing to a contralateral brain volume. The spherical reference method calculates the most probable pre-ischaemic T 2 on a voxel-wise basis, making use of features of the contralateral hemisphere presumed to be largely unaffected. We studied whether T 2 changes in the two main cerebral tissue types, i.e. in grey matter (GM) and white matter (WM), would differ in stroke. Thirty-eight acute stroke patients were accrued within 9 h of symptom onset and scanned at 3 T for 3D T 1-weighted, multi b-value diffusion and multi-echo spin echo MRI for tissue type segmentation, quantitative ADC and absolute T 2 images, respectively. T 2 changes measured by the spherical reference method were 1.94  ±  0.61, 1.50  ±  0.52 and 1.40  ±  0.54 ms h−1 in the whole, GM, and WM lesions, respectively. Thus, T 2 time courses were comparable between GM and WM independent of brain tissue type involved. We demonstrate that T 2 changes in ADC-delineated lesions can be quantified in the clinical setting in a user unbiased manner and that T 2 change correlated with symptom onset time, opening the possibility of using the approach as a tool to assess severity of tissue damage in the clinical setting

    Understanding Behavioral Sources of Process Variation Following Enterprise System Deployment

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    This paper extends the current understanding of the time-sensitivity of intent and usage following large-scale IT implementation. Our study focuses on perceived system misfit with organizational processes in tandem with the availability of system circumvention opportunities. Case study comparisons and controlled experiments are used to support the theoretical unpacking of organizational and technical contingencies and their relationship to shifts in user intentions and variation in work-processing tactics over time. Findings suggest that managers and users may retain strong intentions to circumvent systems in the presence of perceived task-technology misfit. The perceived ease with which this circumvention is attainable factors significantly into the timeframe within which it is attempted, and subsequently impacts the onset of deviation from prescribed practice and anticipated dynamics

    Getting into hot water:sick guppies frequent warmer thermal conditions

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    Ectotherms depend on the environmental temperature for thermoregulation and exploit thermal regimes that optimise physiological functioning. They may also frequent warmer conditions to up-regulate their immune response against parasite infection and/or impede parasite development. This adaptive response, known as ‘behavioural fever’, has been documented in various taxa including insects, reptiles and fish, but only in response to endoparasite infections. Here, a choice chamber experiment was used to investigate the thermal preferences of a tropical freshwater fish, the Trinidadian guppy (Poecilia reticulata), when infected with a common helminth ectoparasite Gyrodactylus turnbulli, in female-only and mixed-sex shoals. The temperature tolerance of G. turnbulli was also investigated by monitoring parasite population trajectories on guppies maintained at a continuous 18, 24 or 32 °C. Regardless of shoal composition, infected fish frequented the 32 °C choice chamber more often than when uninfected, significantly increasing their mean temperature preference. Parasites maintained continuously at 32 °C decreased to extinction within 3 days, whereas mean parasite abundance increased on hosts incubated at 18 and 24 °C. We show for the first time that gyrodactylid-infected fish have a preference for warmer waters and speculate that sick fish exploit the upper thermal tolerances of their parasites to self medicate

    A Systematic Review of Re-Identification Attacks on Health Data

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    Privacy legislation in most jurisdictions allows the disclosure of health data for secondary purposes without patient consent if it is de-identified. Some recent articles in the medical, legal, and computer science literature have argued that de-identification methods do not provide sufficient protection because they are easy to reverse. Should this be the case, it would have significant and important implications on how health information is disclosed, including: (a) potentially limiting its availability for secondary purposes such as research, and (b) resulting in more identifiable health information being disclosed. Our objectives in this systematic review were to: (a) characterize known re-identification attacks on health data and contrast that to re-identification attacks on other kinds of data, (b) compute the overall proportion of records that have been correctly re-identified in these attacks, and (c) assess whether these demonstrate weaknesses in current de-identification methods.Searches were conducted in IEEE Xplore, ACM Digital Library, and PubMed. After screening, fourteen eligible articles representing distinct attacks were identified. On average, approximately a quarter of the records were re-identified across all studies (0.26 with 95% CI 0.046-0.478) and 0.34 for attacks on health data (95% CI 0-0.744). There was considerable uncertainty around the proportions as evidenced by the wide confidence intervals, and the mean proportion of records re-identified was sensitive to unpublished studies. Two of fourteen attacks were performed with data that was de-identified using existing standards. Only one of these attacks was on health data, which resulted in a success rate of 0.00013.The current evidence shows a high re-identification rate but is dominated by small-scale studies on data that was not de-identified according to existing standards. This evidence is insufficient to draw conclusions about the efficacy of de-identification methods
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