259890 research outputs found
Sort by
Protocol for assessing and managing radon gas exposure risks in caves: A case study of Altamira and Paleolithic cave art of Northern Spain World Heritage Site
No full textExposure to radon and its progeny poses a significant health risk for workers in tourist caves. Implementing protective measures is challenging due to increasingly strict gas concentration and dose limits in new regulations. This study evaluates the annual effective radiation doses received by workers and researchers, considering seasonal and spatial radon variability. Radon levels, temperature, and ventilation patterns were continuously monitored for at least one year in each cave. Results show significant radon fluctuations influenced by seasonal ventilation regimes driven by thermal gradients between the cave and external atmosphere. Using International Commission on Radiological Protection guidelines, the study calculates the maximum allowable working hours to comply with European and Spanish regulations, which set an annual dose limit of 20 mSv for occupational exposure. Findings emphasize the necessity of continuous radon monitoring and tailored management strategies, such as adjusting work schedules and restricting access during high-radon periods. Additionally, the study highlights the limitations of passive radon detectors, which tend to underestimate actual radon levels compared to continuous monitoring. This research provides a protocol for managing radon exposure in culturally significant caves while ensuring worker and visitor safety. The methodology includes initial spatial dosimetry, continuous monitoring, and safe working hour recommendations based on monthly radon levels. Monitoring should also consider parameters like temperature, humidity, and CO₂ to understand ventilation dynamics. These measures are essential for compliance with radioprotection standards while preserving the integrity of these unique cultural and historical sites
Changes In Agricultural Land Use and the Effectiveness of Protected Areas: Impacts on the Occurrence of Three Grassland Bird Species in the Carden Plain of Ontario
No full textWe measure changes in occurrence (i.e., presence/absence) of three grassland bird species in the Carden Plain, between 2001 to 2005 and 2015 to 2016, by comparing point count results of the 2001–2005 Ontario Breeding Bird Atlas (OBBA) to repeated point counts at the same sites in the more recent period. We examine associations between changes of occurrence and habitat change and protection status of the survey locations for the three most commonly occurring species of Ontario grassland birds (Bobolink, Dolichonyx oryzivorus; Eastern Meadowlark, Sturnella magna; and Savannah Sparrow, Passerculus sandwichensis), all of which have experienced population declines in Ontario of between 2.75% and 3.87% annually between 1970 and 2019. There was no relationship between changes in the occurrence of these species and the protection designation of sites. Changes in occurrence had a significant association with change in habitat, for all three species with losses of occurrence between the two time periods associated with either shrub succession or conversion to row crops. For Bobolinks and Eastern Meadowlarks, all sites that were converted to row crops lost birds. For Bobolinks, sites experiencing shrub encroachment were also more likely to experience losses. Savannah Sparrows were present in the current period on three of the 10 sites that had been tilled since the OBBA. Gains of all three species were most likely when there had been no change in habitats between the two periods. We suggest targeted removal of trees and shrubs in the Carden Plain on sites where shrubs have not fully established, to help to maintain a healthy grassland bird community
Presenteeism Pressure: The Development of a Scale and a Nomological Network
No full textThe social context of the workplace influences attendance decisions. Regardless of personal and job factors, employees may choose to engage in sickness presenteeism behaviour (i.e., working when unwell) because of perceived pressure from the organization. Using Social Information Processing Theory, we introduce the construct of presenteeism pressure to capture this perception that an organization normalizes and expects employees to engage in presenteeism. Through a scale development study of working adults (N = 219), we create and refine the 11-item Presenteeism Pressure Scale. Next, we provide evidence of convergent and discriminant validity of the scale in an independent sample of working adults (N = 248). We then concurrently examine presenteeism pressure\u27s place in a nomological network of constructs within the presenteeism and broader organizational literature, in another sample (N = 764). Finally, we increase the rigour of our validation efforts by conducting an additional two-wave study (N = 350) and expanding the nomological network of presenteeism pressure to include relevant work outcomes. Our results position presenteeism pressure as a unique and promising contributor to the understanding of presenteeism behaviours and work behaviours more generally. We conclude with suggestions for integrating presenteeism pressure into existing theory and better-informed organizational attendance procedures
Cave bear tracks (Ursichnus europaeus Diedrich, 2011) from Honseca Cave, Palencia, Spain
No full textDiscovery of Laacher See eruption in speleothem record synchronizes Greenland and central European Late Glacial climate change
No full textTo assess the impact of ongoing, historically unprecedented Arctic ice melting, precisely synchronized chronologies are indispensable for past analogs of abrupt climate change. Around 12,900 years before present (B.P.), the Atlantic-European realm experienced an abrupt relapse to near-glacial climate conditions attributed to Arctic meltwater fluxes, the Younger Dryas. However, it remained unclear how fast this climatic change propagated southward into Europe as terrestrial and ice-core chronologies are not sufficiently synchronized. Here, we use a volcanic sulfur spike identified in a speleothem from Germany to link the Laacher See eruption (LSE), a key chronostratigraphic marker in European terrestrial archives, to a previously unidentified sulfate spike in the Greenland ice-core record. The LSE, dated to 13,008 ± 8 years B.P. 1950 , thus synchronizes radiometric and ice-core calendars back in time, which consistently demonstrates that the LSE predates the onset of the Younger Dryas cooling by about 150 years, both in Greenland and Europe