2,529 research outputs found
Motor brush wear measured with strain gages
Balanced bridge circuit, supplied with low-voltage direct current and connected to a readout device, measures remaining brush material, rate of brush wear, armature runout, and brush signature
Measurement of optical to electrical and electrical to optical delays with ps-level uncertainty
We present a new measurement principle to determine the absolute time delay
of a waveform from an optical reference plane to an electrical reference plane
and vice versa. We demonstrate a method based on this principle with 2 ps
uncertainty. This method can be used to perform accurate time delay
determinations of optical transceivers used in fibre-optic time-dissemination
equipment. As a result the time scales in optical and electrical domain can be
related to each other with the same uncertainty. We expect this method to break
new grounds in high-accuracy time transfer and absolute calibration of
time-transfer equipment
Fair Allocation of Scarce Therapies for Coronavirus Disease 2019 (COVID-19)
The US Food and Drug Administration (FDA) has issued emergency use authorizations (EUAs) for monoclonal antibodies (mAbs) for nonhospitalized patients with mild or moderate coronavirus disease 2019 (COVID-19) disease and for individuals exposed to COVID-19 as postexposure prophylaxis. EUAs for oral antiviral drugs have also been issued. Due to increased demand because of the Delta variant, the federal government resumed control over the supply and asked states to ration doses. As future variants (e.g., the Omicron variant) emerge, further rationing may be required. We identify relevant ethical principles (i.e., benefiting people and preventing harm, equal concern, and mitigating health inequities) and priority groups for access to therapies based on an integrated approach to population health and medical factors (eg, urgently scarce healthcare workers, persons in disadvantaged communities hard hit by COVID-19). Using priority categories to allocate scarce therapies effectively operationalizes important ethical values. This strategy is preferable to the current approach of categorical exclusion or inclusion rules based on vaccination, immunocompromised status, or older age, or the ad hoc consideration of clinical risk factors
Fair Allocation at COVID-19 Mass Vaccination Sites
On February 26, 2021, the Federal Emergency and Management Agency (FEMA) announced 18 community vaccination centers in major cities capable of administering up to 6000 vaccines daily. Mass vaccination sites like these arrive amid staggering socioeconomic and racial disparities in COVID-19 vaccination. Black and Hispanic people are being vaccinated at less than half the rate of White people, despite being twice as likely to die of COVID-19. The wealth gap is similarly substantial, reaching up to a 65% difference between the wealthiest and poorest counties in Connecticut. The federal government is supporting mass vaccination sites, in part, to alleviate disparities, asserting that if sites are placed in dense urban areas then “equity is embedded” in their design
The GALFA-HI Compact Cloud Catalog
We present a catalog of 1964 isolated, compact neutral hydrogen clouds from
the Galactic Arecibo L-Band Feed Array Survey Data Release One (GALFA-HI DR1).
The clouds were identified by a custom machine-vision algorithm utilizing
Difference of Gaussian kernels to search for clouds smaller than 20'. The
clouds have velocities typically between |VLSR| = 20-400 km/s, linewidths of
2.5-35 km/s, and column densities ranging from 1 - 35 x 10^18 cm^-2. The
distances to the clouds in this catalog may cover several orders of magnitude,
so the masses may range from less than a Solar mass for clouds within the
Galactic disc, to greater than 10^4 Solar Masses for HVCs at the tip of the
Magellanic Stream. To search for trends, we separate the catalog into five
populations based on position, velocity, and linewidth: high velocity clouds
(HVCs); galaxy candidates; cold low velocity clouds (LVCs); warm, low
positive-velocity clouds in the third Galactic Quadrant; and the remaining warm
LVCs. The observed HVCs are found to be associated with previously-identified
HVC complexes. We do not observe a large population of isolated clouds at high
velocities as some models predict. We see evidence for distinct histories at
low velocities in detecting populations of clouds corotating with the Galactic
disc and a set of clouds that is not corotating.Comment: 34 Pages, 9 Figures, published in ApJ (2012, ApJ, 758, 44), this
version has the corrected fluxes and corresponding flux histogram and masse
Oral health knowledge and practice behaviors among patients with eating disorders: a pilot study
Oral manifestations of eating disorders (ED) have been well documented in the literature. However, the knowledge ED patients have about the effects of the disease on their oral health remains unknown. The purpose of this study is to determine oral health knowledge and oral homecare practice behaviors among ED patients. Oral health knowledge, homecare practice behaviors, and referral patterns of 41 patients currently or previously diagnosed with anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified were measured using an electronic survey. Univariate analysis revealed moderate to high knowledge of the oral manifestations of ED. However, there is a low level of knowledge regarding appropriate post-purging behaviors. Many participants reported brushing (79%) or doing nothing (42.1%) after purging. The rate of referral to a dentist among this population was (32.4%). The most commonly reported barrier to accessing dental care is embarrassment (50%)
A Cold Nearby Cloud Inside the Local Bubble
The high-latitude Galactic H I cloud toward the extragalactic radio source 3C
225 is characterized by very narrow 21 cm emission and absorption indicative of
a very low H I spin temperature of about 20 K. Through high-resolution optical
spectroscopy, we report the detection of strong, very narrow Na I absorption
corresponding to this cloud toward a number of nearby stars. Assuming that the
turbulent H I and Na I motions are similar, we derive a cloud temperature of 20
(+6, -8) K (in complete agreement with the 21 cm results) and a line-of-sight
turbulent velocity of 0.37+/-0.08 km/s from a comparison of the H I and Na I
absorption linewidths. We also place a firm upper limit of 45 pc on the
distance of the cloud, which situates it well inside the Local Bubble in this
direction and makes it the nearest-known cold diffuse cloud discovered to date.Comment: 11 pages, 3 figures, accepted for publication in ApJ Letter
Mapping Hydrogen in the Galaxy, Galactic Halo, and Local Group with ALFA: The GALFA-HI Survey Starting with TOGS
Radio observations of gas in the Milky Way and Local Group are vital for
understanding how galaxies function as systems. The unique sensitivity of
Arecibo's 305m dish, coupled with the 7-beam Arecibo L-Band Feed Array (ALFA),
provides an unparalleled tool for investigating the full range of interstellar
phenomena traced by the HI 21cm line. The GALFA (Galactic ALFA) HI Survey is
mapping the entire Arecibo sky over a velocity range of -700 to +700 km/s with
0.2 km/s velocity channels and an angular resolution of 3.4 arcminutes. We
present highlights from the TOGS (Turn on GALFA Survey) portion of GALFA-HI,
which is covering thousands of square degrees in commensal drift scan
observations with the ALFALFA and AGES extragalactic ALFA surveys. This work is
supported in part by the National Astronomy and Ionosphere Center, operated by
Cornell University under cooperative agreement with the National Science
Foundation.Comment: 3 pages, including 2 figure pages; figure image quality significantly
reduced; for full resolution version, please see
http://www.naic.edu/~gibson/cv/ao08_writeup.pdf ; to be published in AIP
conference proceedings for ``The Evolution of Galaxies through the Neutral
Hydrogen Window'', eds. R. Minchin & E. Momjia
Reconstructing Deconstruction: High-Velocity Cloud Distance Through Disruption Morphology
We present Arecibo L-band Feed Array 21-cm observations of a sub-complex of
HVCs at the tip of the Anti-Center Complex. These observations show
morphological details that point to interaction with the ambient halo medium
and differential drag within the cloud sub-complex. We develop a new technique
for measuring cloud distances, which relies upon these observed morphological
and kinematic characteristics, and show that it is consistent with H-alpha
distances. These results are consistent with distances to HVCs and halo
densities derived from models in which HVCs are formed from cooling halo gas.Comment: 8 pages, 2 figures, 1 tabe, Accepted to Ap
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