719 research outputs found
Moly: a prototype handheld three-dimensional digitizer with diffraction optics
A working handheld 3-D diffraction range finder, nicknamed Moly, is demonstrated. This prototype is distinguished by a far-field magnification feature that is made possible by use of chirped frequency diffraction grating optics that reverse the perspective foreshortening typical of conventional triangulation range finders. This new type of 3-D profilometer illuminates its target with a collimated laser projector that produces a rectangle-shaped sheet of light of uniform width at all working distances. Moly also employs dual magnetic wave detectors to facilitate freedom of movement for both the digitizing instrument and the subject. The instrument was designed primarily to digitize human faces and figures for applications in art and medicine
Rooftop and indoor reception with transmit diversity applied to DVB-T networks: A long term measurement campaign
Although transmit Delay Diversity (DD) can
provide a gain in indoor and other Non Line of Sight situations (NLOS), it can introduce degradation in rooftop reception. In fact, when the Ricean K factor of the channel
is significantly high (e.g. Line of Sight reception), the channel performs similar to an AWGN channel where the performance degrades due to DD that artificially increase
the fading. This paper investigates through practical evaluation the impacts of Transmit DD on LOS and NLOS stationary reception. Then, it studies 2 techniques to reduce the degradation performance in LOS while aiming
to keep the same diversity gain in NLOS receptio
Skin prick testing does not reflect the presence of IgE against food allergens in adult eosinophilic esophagitis patients: a case study
Skin prick testing is widely used to predict the presence of allergen-specific IgE. In eosinophilic esophagitis patients, who frequently exhibit polysensitization and broad reactivity upon skin prick testing, this is commonly used to aid avoidance recommendations in the clinical management of their disease. We present here the predictive value of skin prick testing for the presence of allergen-specific IgE, in 12 patients, determined by immunoblot against the allergen extracts using individual-matched serum. Our results demonstrate a high degree of predictive value for aeroallergens but a poor predictive value for food allergens. This suggests that skin prick testing likely identifies IgE reactivity towards aeroallergens in adult eosinophilic esophagitis but this is not true for foods. Consequently, IgE immunoblotting might be required for determining food avoidance in these patients
Pulsation period variations in the RRc Lyrae star KIC 5520878
Learned et. al. proposed that a sufficiently advanced extra-terrestrial
civilization may tickle Cepheid and RR Lyrae variable stars with a neutrino
beam at the right time, thus causing them to trigger early and jogging the
otherwise very regular phase of their expansion and contraction. This would
turn these stars into beacons to transmit information throughout the galaxy and
beyond. The idea is to search for signs of phase modulation (in the regime of
short pulse duration) and patterns, which could be indicative of intentional,
omnidirectional signaling.
We have performed such a search among variable stars using photometric data
from the Kepler space telescope. In the RRc Lyrae star KIC 5520878, we have
found two such regimes of long and short pulse durations. The sequence of
period lengths, expressed as time series data, is strongly auto correlated,
with correlation coefficients of prime numbers being significantly higher
(\%). Our analysis of this candidate star shows that the prime number
oddity originates from two simultaneous pulsation periods and is likely of
natural origin.
Simple physical models elucidate the frequency content and asymmetries of the
KIC 5520878 light curve.
Despite this SETI null result, we encourage testing other archival and future
time-series photometry for signs of modulated stars. This can be done as a
by-product to the standard analysis, and even partly automated.Comment: Accepted for publication in ApJ. 49 pages, 16 figure
Studying the Psychological Impacts of the COVID-19 Pandemic on Frontline Healthcare Workers
Purpose: The purpose of this study was to determine the prevalence of psychological distress in frontline healthcare workers during the COVID 19 pandemic, and to identify if interventions and higher measures of resiliency helped to minimize the prevalence of symptoms.https://scholarlycommons.henryford.com/nursresconf2021/1002/thumbnail.jp
Chaogates: morphing logic gates that exploit dynamical patterns
Chaotic systems can yield a wide variety of patterns. Here we use this feature to generate all possible fundamental logic gate functions. This forms the basis of the design of a dynamical computing device, a chaogate, that can be rapidly morphed to become any desired logic gate. Here we review the basic concepts underlying this and present an extension of the formalism to include asymmetric logic functions
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