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Over the last 25 years, radiowave detection of neutrino-generated signals, using cold polar ice as the neutrino target, has emerged as perhaps the most promising technique for detection of extragalactic ultra-high energy neutrinos (corresponding to neutrino energies in excess of 0.01 Joules, or 1017 electron volts). During the summer of 2021 and in tandem with the initial deployment of the Radio Neutrino Observatory in Greenland (RNO-G), we conducted radioglaciological measurements at Summit Station, Greenland to refine our understanding of the ice target. We report the result of one such measurement, the radio-frequency electric field attenuation length $L_\alpha$. We find an approximately linear dependence of $L_\alpha$ on frequency with the best fit of the average field attenuation for the upper 1500 m of ice: $\langle L_\alpha \rangle = ( ( 1154 \pm 121) - ( 0.81 \pm 0.14) \, ( \nu /{\rm MHz}) ) \,{\rm m}$ for frequencies ν ∈ [145 − 350] MHz.
Nurses and paramedics by being the frontline workers of the health-care profession need to be equipped with the relevant knowledge, skills, and protective gears against different forms of infection, including coronavirus disease 2019 (COVID-19). Although the governments and concerned stakeholders have provided personal protective equipment (PPE), training and information to protect the health-care professionals; however, until now the scientific literature has virtually not reported the impact of PPE availability, training, and practices on the COVID-19 sero-prevalence among the nurses and paramedics. This study aimed to assess the impact of PPE availability, training, and practices on COVID-19 sero-prevalence among nurses and paramedics in teaching hospitals of Peshawar, Pakistan.
Methods:
A cross-sectional survey was conducted with a total of 133 nurses and paramedics as subjects of the study.
Results:
A univariate analysis was done for 4 variables. The findings indicate that the health-care professionals (nurses and paramedics) who have received PPE on time at the start of COVID-19 emergence have fewer chances of contracting the COVID-19 infection (odds ratio = 0.96); while the odds for PPE supplies was 0.73, and the odds of hand hygiene training was 0.95.
Conclusions:
The study concluded that the availability of the PPE, COVID-19–related training, and compliance with World Health Organization recommended practices against COVID-19 were instrumental in protection against the infection and its spread.
The Askaryan Radio Array (ARA) experiment at the South Pole is designed to detect high-energy neutrinos which, via in-ice interactions, produce coherent radiation at frequencies up to 1000 MHz. Characterization of ice birefringence, and its effect upon wave polarization, is proposed to enable range estimation to a neutrino interaction and hence aid in neutrino energy reconstruction. Using radio transmitter calibration sources, the ARA collaboration recently measured polarization-dependent time delay variations and reported significant time delays for trajectories perpendicular to ice flow, but not parallel. To explain these observations, and assess the capability for range estimation, we use fabric data from the SPICE ice core to model ice birefringence and construct a bounding radio propagation model that predicts polarization time delays. We compare the model with new data from December 2018 and demonstrate that the measurements are consistent with the prevailing horizontal crystallographic axis aligned near-perpendicular to ice flow. The study supports the notion that range estimation can be performed for near flow-perpendicular trajectories, although tighter constraints on fabric orientation are desirable for improving the accuracy of estimates.
There are concerns over the outcome of device closure of secundum atrial septal defect with special reference to erosions and aortic regurgitation.
Aim
To assess the medium-term outcome of device closure of atrial septal defects with special reference to complications.
Methods
A total of 205 patients with secundum atrial septal defects underwent transcatheter closure from October, 1999 to April, 2009. The median age was 18 (1.4–55) years. Amplatzer Septal Occluder was used in all the patients. Medium-term follow-up was available in 176 of 200 (88%) patients.
Results
Device closure was successful in 200 out of 205 (98%) patients. The device embolised in four patients and was associated with short inferior caval vein margin (p = 0.003). Balloon sizing in 71 patients (35%) resulted in implantation of a larger device (p = 0.002). Early complications included pericardial effusion, 2:1 heart block, and infective endocarditis (1 patient each). There were eight patients who reported migraine (3.9%). At median follow-up of 5.8 (0.6–10.3) years, complete closure occurred in 197 out of 200 patients. Short superior caval vein margin was associated with a residual shunt (p < 0.001). There were two patients who developed mild aortic regurgitation (1%), which correlated with a device-to-defect ratio of >1.3:1 (p = 0.001). There were no erosions, late embolisation, or thromboembolism. Atrial fibrillation occurred in three adults (1.5%).
Conclusions
Device closure of secundum atrial septal defects using Amplatzer Septal Occluder is safe and effective in the medium term. Short inferior caval vein margin correlates with increased risk of embolisation and short superior caval vein margin with a residual shunt. The risk of developing aortic regurgitation is low and correlates with increased device-to-defect ratio.
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