389 research outputs found
Transition to Virtual Asthma Care During the COVID-19 Pandemic: An Observational Study
BACKGROUND: The COVID-19 pandemic increased reliance
on virtual care for patients with persistent asthma.
OBJECTIVE: This retrospective cohort study assessed changes
from in-person to virtual care during the pandemic. In patients
with persistent asthma, compared with the same period before
the pandemic.
METHODS: Kaiser Permanente Colorado members aged 18 to
99 years with persistent asthma were evaluated during two
periods (March to October 2019 and March to October 2020).
Comparison of asthma exacerbations (hospitalizations,
emergency department visits, and courses of oral prednisone)
and asthma medication metrics were evaluated between the two
periods and by type of care received during the pandemic (no
care, virtual care only, in-person care only, or a mix of virtual
and in-person care). Population characteristics by type of care
received during the pandemic were also evaluated.
RESULTS: Among 7,805 adults with persistent asthma, those
who used more virtual care or sought no care during the
pandemic were younger and had fewer comorbidities, mental
health diagnoses, or financial barriers. Exacerbations decreased
(0.264 to 0.214; P <.001) as did courses of prednisone (0.213 to
0.169). Asthma medication adherence (0.53 to 0.54; P <.001)
and the asthma medication ratio, a quality-of-care metric (0.755
to 0.762; P [ .019), increased slightly. Patients receiving a mix
of in-person and virtual care had the highest rate of exacerbations (0.83) and a lower asthma medication ratio (0.74) despite
having the highest adherence (.57).
CONCLUSIONS: Despite an increase in virtual care, asthma
exacerbations decreased except among individuals who received
both in-person and virtual care, likely because they had more severe disease.Ye
A Survey of the Northern Sky for TeV Point Sources
A search for steady TeV point sources anywhere in the northern sky has been
made with data from the Milagrito air-shower-particle detector. Over 3 x 10**9
events collected from 1997 February to 1998 May have been used in this study.
No statistically significant excess above the background from the isotropic
flux of cosmic rays was found for any direction of the sky with declination
between -5 degrees and 71.7 degrees. Upper limits are derived for the photon
flux above 1 TeV from any steady point source in the northern sky.Comment: 2 Figure
The high-energy gamma-ray fluence and energy spectrum of GRB 970417a from observations with Milagrito
Evidence of TeV emission from GRB970417a has been previously reported using
data from the Milagrito detector. Constraints on the TeV fluence and the energy
spectrum are now derived using additional data from a scaler system that
recorded the rate of signals from the Milagrito photomultipliers. This analysis
shows that if emission from GRB970417a has been observed, it must contain
photons with energies above 650 GeV. Some consequences of this observation are
discussed.Comment: Submitted to the Astrophysical Journa
Evidence for TeV Emission from GRB 970417a
Milagrito, a detector sensitive to very high energy gamma rays, monitored the
northern sky from February 1997 through May 1998. With a large field of view
and a high duty cycle, this instrument was well suited to perform a search for
TeV gamma-ray bursts (GRBs). We report on a search made for TeV counterparts to
GRBs observed by BATSE. BATSE detected 54 GRBs within the field of view of
Milagrito during this period. An excess of events coincident in time and space
with one of these bursts, GRB 970417a, was observed by Milagrito. The excess
has a chance probability of of being a fluctuation of the
background. The probability for observing an excess at least this large from
any of the 54 bursts is . No significant correlations were
detected from the other bursts.Comment: 10 pages, 3 figure
First results of a study of TeV emission from GRBs in Milagrito
Milagrito, a detector sensitive to Îł-rays at TeV energies, monitored the northern sky during the period February 1997 through May 1998. With a large field of view and high duty cycle, this instrument was used to perform a search for TeV counterparts to Îł-ray bursts. Within the Milagrito field of view 54 Îł-ray bursts at keV energies were observed by the Burst And Transient Satellite Experiment (BATSE) aboard the Compton Gamma-Ray Observatory. This paper describes the results of a preliminary analysis to search for TeV emission correlated with BATSE detected bursts. Milagrito detected an excess of events coincident both spatially and temporally with GRB 970417a, with chance probability 2.8Ă10â5 within the BATSE error radius. No other significant correlations were detected. Since 54 bursts were examined the chance probability of observing an excess with this significance in any of these bursts is 1.5Ă10â3. The statistical aspects and physical implications of this result are discussed
Milagro: A TeV observatory for gamma-ray bursts
Observation of prompt TeV Îł-rays from GRBs requires a new type of detector to overcome the low duty factor and small field of view of current TeV observatories. Milagro is such a new type of very high energy (\u3e a few 100 GeV) gamma-ray observatory, which has a large field of view of \u3e1 steradian and 24 hours/day operation. Milagrito, a prototype for Milagro, was operated from February 1997 to May 1998. During the summer of 1998, Milagrito was dismantled and Milagro was built. Both detectors use a 80âmĂ60âmĂ8âm pond of water in which a 3âmĂ3âm grid of photomultiplier tubes detects the Cherenkov light produced in the water by the relativistic particles in extensive air showers. Milagrito was smaller and had only one layer of photomultipliers, but allowed the technique to be tested. Milagrito observations of the Moonâs shadow and Mrk 501 are consistent with the Monte Carlo prediction of the telescopeâs parameters, such as effective area and angular resolution. Milagro will have improved flux sensitivity over Milagrito due to larger effective area, better angular resolution and cosmic-ray background rejection
Milagro: A TeV gamma-ray monitor of the Northern Hemisphere Sky
A new type of very high energy (\u3e a few 100 GeV) gamma-ray observatory, Milagro, has been built with a large field of view of \u3e1 steradian and nearly 24 hours/day operation. Milagrito, a prototype for Milagro, was operated from February 1997 to May 1998. During the summer of 1998, Milagrito was dismantled and Milagro was built. Both detectors use a 80âmĂ60âmĂ8âmpond of water in which a 3âmĂ3âm grid of photomultiplier tubes detects the Cherenkov light produced in the water by the relativistic particles in extensive air showers. Milagrito was smaller and had only one layer of photomultipliers, but allowed the technique to be tested. Milagrito observations of the Moonâs shadow and Mrk 501 are consistent with the Monte Carlo prediction of the telescopes parameters, such as effective area and angular resolution. Milagro is larger and consists of two layers of photomultiplier tubes. The bottom layer detects penetrating particles that are used to reject the background of cosmic-ray initiated showers
TeV Observations of Markarian 501 with the Milagrito Water Cherenkov Detector
The Milagrito water Cherenkov detector near Los Alamos, New Mexico, operated
as a sky monitor at energies of a few TeV between February 1997 and May 1998
including the period of the strong, long-lasting 1997 flare of Markarian 501.
Milagrito served as a test run for the full Milagro detector. An event excess
with a significance of 3.7 sigma from Markarian 501 was observed, in agreement
with expectations.Comment: 10 pages, 3 figures (figure 2 in color). accepted for publication in
ApJ Letter
Results from the Milagrito experiment
The Milagro water Cherenkov detector near Los Alamos, New Mexico is the first air shower detector capable of continuously monitoring the sky at energies between 500 GeV and 20 TeV. Preliminary results of the Milagro experiment are presented. A predecessor of the Milagro detector, Milagrito, was operational from February 1997 to May 1998. Milagrito consisted of 228 8âł photomultiplier tubes (PMTs) arranged in a grid with a 2.8 meter spacing and submerged in 1â2 meters of water. During its operation, Milagrito collected in excess of 9 billion events with a median energy of about 3 TeV. The detectorâs sensitivity extends below 1 TeV for showers from near zenith. The results of an all sky search for the Milagrito data for both transient and DC sources will be presented, including the Crab Nebula and active galaxies Markarian 501 and 421, which are known sources of TeV gamma-rays. Also presented will be a study of the TeV emission from gamma ray bursts (GRBs) in Milagritoâs field of view detected by the BATSE experiment on the Compton Gamma-Ray Observatory
The Milagro gamma-ray observatory
The Milagro water Cherenkov detector began full operation in January 2000. This detector is capable of monitoring the Northern sky at energies above 500 GeV for sources of equivalent strength to the Crab Nebula over one year of integration. We report on the current performance and sensitivity of Milagro
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