42 research outputs found
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Abstracts of presentations on plant protection issues at the xth international congress of virology: August 11-16,1996 Binyanei haOoma, Jerusalem, Israel Part 2 Plenary Lectures
Milk β-hydroxybutyrate concentration measured by Fourier-transform infrared and flow-injection analyses from samples taken at different times relative to milking
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Abstract 04: Validation of the Instant Blood Pressure Smartphone Application (App)
Introduction:
Mobile health (‘mHealth’) technologies include unregulated smartphone apps. Instant Blood Pressure (IBP; AuraLife, Newport Beach, CA) estimates blood pressure (BP) using the integrated sensors in the phone, without requiring a cuff. For 392 days in 2014-15, it was a top 50 best-selling iPhone app in the US (requiring ≥950 copies sold on those days). App store reviews document use of the app for treatment of hypertension. IBP has not been independently validated.
Hypothesis:
The absolute mean difference (MD) between IBP and a standard device will be ≤5.0 mmHg for systolic and diastolic BP measurements.
Methods:
Between Jul. and Sep. 2015, we enrolled adults age ≥18 yrs old, at Johns Hopkins clinics. Exclusion criteria were an active arrhythmia, internal device, or contraindication for arm BP measurement. Two order-randomized measurements were taken on two devices: IBP and a validated standard device (Omron-907). Each IBP measurement was compared to the average of the standard measurements. SBP and DBP MD were log transformed and T-tests were used to compare MD and the cutoff of ≤5.0 mmHg.
Results:
Of 85 participants, 52% (44 of 85) were women, mean ± SD age was 57 ± 16 years, and mean BMI was 28 ± 6 kg/m2; 53% (45 of 85) had hypertension. The mean ± SD absolute BP differences (IBP minus standard) were 12.4 ± 10.5 mmHg for systolic (P<0.001) and 10.1 ± 8.1 mmHg for diastolic BP (P<0.001). The app overestimated low BP and underestimated high BP (Figure). Sensitivity and specificity for hypertensive measurements (systolic ≥140 or diastolic ≥90 mmHg) were 0.2 and 0.9.
Conclusions:
BP measurements from an unregulated mHealth app with >148,000 units sold were highly inaccurate. The low sensitivity for hypertensive readings means that four-fifths of individuals with hypertensive BP levels will be falsely reassured that their BP is in the non-hypertensive range
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Auralife Instant Blood Pressure App in Measuring Resting Heart Rate: Validation Study
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User experience of instant blood pressure: exploring reasons for the popularity of an inaccurate mobile health app
Instant blood pressure (IBP) is a top-selling yet inaccurate blood pressure (BP)-measuring app that underreports elevated BP. Its iTunes app store user ratings and reviews were generally positive. Whether underreporting of elevated BP improves user experience is unknown. Participants enrolled at five clinics estimated their BP, measured their BP with IBP, then completed a user experience survey. Participants were grouped based on how their IBP BP measurements compared to their estimated BP (IBP Lower, IBP Similar, or IBP Higher). Logistic regressions compared odds of rating “agree” or “strongly agree” on survey questions by group. Most participants enjoyed using the app. In the adjusted model, IBP Higher had significantly lower proportions reporting enjoyment and motivation to check BP in the future than IBP Similar. All three groups were comparable in perceived accuracy of IBP and most participants perceived it to be accurate. However, user enjoyment and likelihood of future BP monitoring were negatively associated with higher-than-expected reported systolic BP. These data suggest reassuring app results from an inaccurate BP-measuring app may have improved user experience, which may have led to more positive user reviews and greater sales. Systematic underreporting of elevated BPs may have been a contributor to the app’s success. Further studies are needed to confirm whether falsely reassuring output from other mobile health apps improve user experience and drives uptake