Radon-222 activity concentration has been monitored since 1999 in an underground limestone quarry located in Vincennes, near Paris, France. It is homogeneous in summer, with an average value of 1700 Bq m(-3), and varies from 730 to 1450 Bq m(-3) in winter, indicating natural ventilation with a rate ranging from 0.5 to 2.4 x 10(-6) s(-1) (0.04-0.22 day(-1)). This hypothesis is supported by measurements in the vertical access pit where, in winter, a turbulent air current produces a stable radon profile, smoothly decreasing from 700 Bq m(-3) at 20 m depth to 300 Bq m(-3) at surface. In summer, a thermal stratification is maintained in the pit, but the radon-222 concentration jumps repeatedly between 100 and 2000 Bq m(-3). These jumps are due to atmospheric pressure pumping, which induces ventilation in the quarry at a rate of about 0.1 x 10(-6) s(-1) (0.009 day(-1)). Radon-222 monitoring thus provides a dynamical characterisation of ventilation regimes, which is important for the assessment of the long-term evolution of underground systems.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/S0265-931X(03)00117-6 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Research on leakage and diffusion behavior of hydrogen doped natural gas in integrated pipeline corridors based on data drive.
Sci Rep
January 2025
Northwest Sichuan Gas District of Southwest Oil and Gasfield Company, Jiangyou, 621700, China.
With the wide application of hydrogen-doped natural gas (HBNG) in end users, laying pipelines in urban, comprehensive pipe corridors has become increasingly common. However, the leakage and diffusion of hydrogen-doped natural gas in confined or semi-confined spaces (e.g.
View Article and Find Full Text PDFEffects of Variable Ventilation on Gas Exchange in an Experimental Model of Capnoperitoneum: A Randomized Crossover Study.
Anesth Analg
January 2025
From the Unit for Anaesthesiological Investigations, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland.
Background: The rapid advancement of minimally invasive surgical techniques has made laparoscopy a preferred alternative because it reduces postoperative complications. However, inflating the peritoneum with CO2 causes a cranial shift of the diaphragm decreasing lung volume and impairing gas exchange. Additionally, CO2 absorption increases blood CO2 levels, further complicating mechanical ventilation when the lung function is already compromised.
View Article and Find Full Text PDFDistribution and role of peripheral arterial chemoreceptors in cardio-respiratory control of the south american rattlesnake (Crotalus durissus).
J Exp Biol
January 2025
Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Peripheral arterial chemoreceptors monitor the levels of arterial blood gases and adjust ventilation and perfusion to meet metabolic demands. These chemoreceptors are present in all vertebrates studied to date but have not been described fully in reptiles other than turtles. The goals of this study were to 1) identify functional chemosensory areas in the South American rattlesnake (Crotalus durissus) 2) determine the neurochemical content of putative chemosensory cells in these areas and 3) determine the role each area plays in ventilatory and cardiovascular control.
View Article and Find Full Text PDFRisk factor of postoperative pulmonary complications after colorectal cancer surgery: an analysis of nationwide inpatient sample.
Sci Rep
January 2025
Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China.
To investigate the incidence rate, risk factors, and clinical implications of postoperative pulmonary complications (PPCs) in patients undergoing colorectal cancer surgery (CRC). The study extracted data from the National Inpatient Sample (NIS) between 2010 and 2019. Patients' data were analyzed to identify predictors of PPCs, and the association between possible factors and PPCs were also assessed.
View Article and Find Full Text PDFComparison of the Effect of the White Noise and Sound Reduction on Behavioral Responses of Premature Infants Under Noninvasive Ventilation: A Clinical Trial.
J Perinat Neonatal Nurs
January 2025
Author Affiliations: Department of Pediatric and Neonatal Nursing, School of Nursing and Midwifery, Mashhad University of Medical Sciences, Mashhad, Iran (Mrs Mohseni and Dr Ramezani); Nursing and Midwifery Care Research Center, Mashhad University of Medical Sciences, Mashhad, Iran Mrs (Dr Ramezani); Department of Epidemiology and Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran (Dr Saki); and Neonatologist, NICU Department, Hakim Hospital, Neyshabur University of Medical Sciences, Neyshabur, Iran (Dr Poor-Alizadeh).
With the increasing survival rates of premature infants and their associated respiratory problems, noninvasive ventilation has gained popularity in neonatal intensive care units. On the other hand, this equipment can be stressful for infants. Objective: This study aimed to compare the effects of white noise and sound reduction on the behavioral responses of premature infants under noninvasive ventilation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!