2,747 research outputs found
Transport Out of the Antarctic Polar Vortex from a Three-dimensional Transport Model
[1] A three-dimensional chemical transport model is utilized to study the transport out of the Antarctic polar vortex during the southern hemisphere spring. On average, over five consecutive years between 1993 and 1997, horizontal transport out of the vortex into the midlatitude stratosphere is smaller than vertical transport into the troposphere. However, there is significant interannual variability in the magnitude of mass exchange, which is related to year-to-year fluctuations in planetary wave activity. In 1994 the net loss of the vortex tracer mass in September is similar to that in October. However, the relative mass flux entering the midlatitude stratosphere and the troposphere differ between the two months. The ratio of horizontal transport out of the vortex to vertical transport into the troposphere is about 3:7 in September and 5:5 in October, indicating the higher permeability of the vortex in October compared to September. The September mass flux into the troposphere is larger than in October, consistent with the fact that stronger diabatic cooling occurs in September than October over Antarctica. The estimated ozone change at southern midlatitudes due to the intrusion of ozone-depleted air from high latitudes during September–October 1994 is about −0.44% per decade, which could contribute up to 10% of observed ozone decline at southern midlatitudes in spring. This amount is an underestimate of the dilution effect from high latitudes during the spring season, as it does not include the vortex breakup in late spring
Multi-donor × elite-based populations reveal QTL for low-lodging wheat
Low-lodging high-yielding wheat germplasm and SNP-tagged novel alleles for lodging were identified in a process that involved selecting donors through functional phenotyping for underlying traits with a designed phenotypic screen, and a crossing strategy involving multiple-donor × elite populations
Associations of physical activity and quality of life in parapneumonic effusion patients
Introduction Little is known about activity behaviours and quality of life (QoL) of patients with parapneumonic pleural effusions (PPE) after hospital discharge. This study is a secondary analysis of a randomised trial (dexamethasone versus placebo) for hospitalised patients with PPE. We: 1) described the patients’ activity behaviour patterns and QoL measured at discharge and at 30 days post-discharge; and 2) examined the association between activity behaviours and QoL scores. Methods Activity behaviour (7-day accelerometry; Actigraph GT3X+) and QoL (Medical Outcomes Study Short-Form 36) were assessed. Repeated measures analysis of covariance controlling for baseline values and a series of linear regression models were undertaken. Results 36 out of 53 eligible participants completed accelerometry assessments. Despite modest increases in light physical activity (+7.5%) and some domains of QoL ( \u3e 2 points) from discharge to 30 days post-discharge, patients had persistently high levels of sedentary behaviour ( \u3e 65% of waking wear time) and poor QoL ( ⩽ 50 out of 100 points) irrespective of treatment group ( p=0.135–0.903). Increasing moderate-to-vigorous physical activity was associated with higher scores on most QoL domains ( p=0.006–0.037). Linear regression indicates that a clinically important difference of 5 points in physical composite QoL score can be achieved by reallocating 16.1 min·day−1 of sedentary time to moderate-to-vigorous physical activity. Conclusion Patients with PPE had low levels of physical activity and QoL at discharge and 30 days post-discharge irrespective of treatment. Moderate-to-vigorous physical activity participation was associated with higher QoL scores. Increasing moderate-to-vigorous physical activity following discharge from the hospital may be associated with improvements in QoL. © The authors 2023
Superconducting nanowire photon number resolving detector at telecom wavelength
The optical-to-electrical conversion, which is the basis of optical
detectors, can be linear or nonlinear. When high sensitivities are needed
single-photon detectors (SPDs) are used, which operate in a strongly nonlinear
mode, their response being independent of the photon number. Nevertheless,
photon-number resolving (PNR) detectors are needed, particularly in quantum
optics, where n-photon states are routinely produced. In quantum communication,
the PNR functionality is key to many protocols for establishing, swapping and
measuring entanglement, and can be used to detect photon-number-splitting
attacks. A linear detector with single-photon sensitivity can also be used for
measuring a temporal waveform at extremely low light levels, e.g. in
long-distance optical communications, fluorescence spectroscopy, optical
time-domain reflectometry. We demonstrate here a PNR detector based on parallel
superconducting nanowires and capable of counting up to 4 photons at
telecommunication wavelengths, with ultralow dark count rate and high counting
frequency
Sex-differences in oral anticoagulation therapy in patients hospitalized with atrial fibrillation:a nationwide cohort study
Background Important disparities in the treatment and outcomes of women and men with atrial fibrillation (AF) are well recognized. Whether introduction of direct oral anticoagulants has reduced disparities in treatment is uncertain. Methods and Results All patients who had an incident hospitalization from 2010 to 2019 with nonvalvular AF in Scotland were included in the present cohort study. Community drug dispensing data were used to determine prescribed oral anticoagulation therapy and comorbidity status. Logistic regression modeling was used to evaluate patient factors associated with treatment with vitamin K antagonists and direct oral anticoagulants. A total of 172 989 patients (48% women [82 833 of 172 989]) had an incident hospitalization with nonvalvular AF in Scotland between 2010 and 2019. By 2019, factor Xa inhibitors accounted for 83.6% of all oral anticoagulants prescribed, while treatment with vitamin K antagonists and direct thrombin inhibitors declined to 15.9% and 0.6%, respectively. Women were less likely to be prescribed any oral anticoagulation therapy compared with men (adjusted odds ratio [aOR], 0.68 [95% CI, 0.67–0.70]). This disparity was mainly attributed to vitamin K antagonists (aOR, 0.68 [95% CI, 0.66–0.70]), while there was less disparity in the use of factor Xa inhibitors between women and men (aOR, 0.92 [95% CI, 0.90–0.95]). Conclusions Women with nonvalvular AF were significantly less likely to be prescribed vitamin K antagonists compared with men. Most patients admitted to the hospital in Scotland with incident nonvalvular AF are now treated with factor Xa inhibitors and this is associated with fewer treatment disparities between women and men
Extragalactic millimeter-wave sources in South Pole Telescope survey data: source counts, catalog, and statistics for an 87 square-degree field
We report the results of an 87 square-degree point-source survey centered at
R.A. 5h30m, decl. -55 deg. taken with the South Pole Telescope (SPT) at 1.4 and
2.0 mm wavelengths with arc-minute resolution and milli-Jansky depth. Based on
the ratio of flux in the two bands, we separate the detected sources into two
populations, one consistent with synchrotron emission from active galactic
nuclei (AGN) and one consistent with thermal emission from dust. We present
source counts for each population from 11 to 640 mJy at 1.4 mm and from 4.4 to
800 mJy at 2.0 mm. The 2.0 mm counts are dominated by synchrotron-dominated
sources across our reported flux range; the 1.4 mm counts are dominated by
synchroton-dominated sources above ~15 mJy and by dust-dominated sources below
that flux level. We detect 141 synchrotron-dominated sources and 47
dust-dominated sources at S/N > 4.5 in at least one band. All of the most
significantly detected members of the synchrotron-dominated population are
associated with sources in previously published radio catalogs. Some of the
dust-dominated sources are associated with nearby (z << 1) galaxies whose dust
emission is also detected by the Infrared Astronomy Satellite (IRAS). However,
most of the bright, dust-dominated sources have no counterparts in any existing
catalogs. We argue that these sources represent the rarest and brightest
members of the population commonly referred to as sub-millimeter galaxies
(SMGs). Because these sources are selected at longer wavelengths than in
typical SMG surveys, they are expected to have a higher mean redshift
distribution and may provide a new window on galaxy formation in the early
universe.Comment: 35 emulateapj pages, 12 figures, 5 table
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