Search results for "snowball"
showing 4 items of 14 documents
A mechanism for brief glacial episodes in the Mesozoic greenhouse
2011
[1] The Mesozoic, perhaps the longest period of warmth during the Phanerozoic Earth history, has been repeatedly affected by short-lived cold interludes lasting about one million years. While the origin of these cold snaps has been classically attributed to a temporary atmospheric CO2 drawdown, quantified mechanisms explaining these instabilities of the carbon cycle are still lacking. Based on a climate carbon cycle model, we show that the general demise of carbonate platforms accompanying these short-lived cold interludes is a powerful mechanism capable of generating a fast atmospheric CO2 decrease and a moderate sea level drop associated with ice sheet buildup. The temporary nature of the…
Rapid Assessment of COVID-19 Screening Program for Travelers in Iran: A Qualitative Study
2022
AbstractObjective:Coronavirus disease 2019 (COVID-19) screening stations set up by Iranian Red Crescent Society have been available for 17 d with the aim of identifying and treating people with coronavirus, reducing road trips, and sensitizing people to the problem. This study aims to investigate the challenges of the procedure.Methods:A qualitative study was used to find the challenges of the COVID-19 screening centers. Volunteers, branch managers, and headquarter managers of the Iranian Red Crescent Society participated in this study applying snowball sampling. Data were collected by means of in-depth semi-structured telephone interviews in April 2020 after completion of the fever screeni…
Going through the lockdown: a longitudinal study on the psychological consequences of the coronavirus pandemic
2021
Coronavirus 2019 pandemic lockdown in Italy lasted for 2 months, 1 week and 2 days. During this long period, one of the longest in Europe, the restrictions produced effects on people’s psychological well-being, with consequences that also continued after lockdown. The purpose of the study is to investigate these effects and how they changed in the general population over a period of time. We are also interested in exploring people’s post-lockdown anxiety and concerns. We conducted an online survey using snowball sampling techniques. The longitudinal study consisted of four administrations covering a period of 10 weeks between April (baseline) and June (last follow-up). Levels of anxiety and…
Transport and extraction of radioactive ions stopped in superfluid helium
2003
A new approach to convert a high energy beam to a low energy one, which is essential for the next generation radioactive ion beam facilities, has been proposed and tested at Jyvaskyla, Finland. An open Ra-223 alpha-decay-recoil source has been used to produce radioactive ions in superfluid helium. The alpha spectra demonstrate that the recoiling Rn-219 ions have been extracted out of liquid helium. This first observation of the extraction of heavy positive ions across the superfluid helium surface was possible thanks to the high sensitivity of radioactivity detection. An efficiency of 36% was obtained for the ion extraction out of liquid helium. (C) 2003 Elsevier Science B.V. All rights res…