32 research outputs found

    Global maps of soil temperature

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    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world\u27s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

    Global maps of soil temperature

    Get PDF
    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km² resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e., offset) between in-situ soil temperature measurements, based on time series from over 1200 1-km² pixels (summarized from 8500 unique temperature sensors) across all the world’s major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in-situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

    Global maps of soil temperature.

    Get PDF
    Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications

    Educational background of Flemish dental practitioners and their perceptions of their managment of dental trauma

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    AIM: The aim of this study was to analyze whether any correlation existed between Flemish dental practitioner's educational background and their perceptions of their knowledge regarding emergency treatment for crown fractures and their actual expertise. METHODS: A questionnaire was distributed among 336 dental practitioners at six different locations in the country and completed prior to a lecture on dental traumatology. The response rate was 100%. The questionnaire consisted of three parts: the first part enquired about personal background, the second part requested a self-assessment of the practitioner's dental trauma education and treatment experience, and the third part tested the knowledge of the practitioner by asking for responses to different options for emergency treatment for dental trauma. RESULTS: Nearly 63% of the participants had more than 20 years of experience. Satisfaction about adequacy in basic education in dental traumatology was significantly related to the years as graduation to older graduates being less satisfied. This observation was not related to the additional education taken. Most frequently, uncomplicated crown fractures (42%) were seen more frequently than severe injuries. Concerning knowledge, a high result (67%) of incorrect answers was given for the treatment for injured immature permanent incisors. However, a high correlation was found between good knowledge of treatment and young professionals who graduated <10 years ago. Referring dental injuries for treatment was correlated with increasing level of difficulty. In the permanent dentition, however, complicated crown fractures (CCF) in immature teeth were not referred in many (66%) cases. CONCLUSION: It was observed that the knowledge of Flemish dental practitioners regarding emergency treatment for CCF is insufficient especially for the management of immature incisors

    Fracture resistance of bone samples filled with fibre-reinforced composite posts: an ex vivo model

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    Aim: To evaluate the strengthening effect of two different types of fibre-reinforced composite (FRC) posts in an ex vivo experimental model. Methodology: Compact and hollow bone samples from bovine femurs were used as standardized samples. A total of 80 hollow samples were divided into two groups and filled either with a prefabricated FRC post or with individually adapted FRC posts. For each group, half of the samples were subjected to thermocycling (555 degrees C, 5000x). The remaining samples were kept for 24h at 37 degrees C at 100% relative humidity. All samples were loaded diametrically until fracture. The null hypothesis tested was that the fracture resistance of standardized bone samples is not influenced by the type of FRC post, independently of the exposure to thermocycling. Results were evaluated by anova, and subsequent multiple comparisons were performed. Results: The samples filled with the individually adapted FRC posts were more resistant to fracture than the prefabricated ones (P<0.001), but this difference was not apparent in the thermocycled groups. Detachment of the posts upon fracture was highest after thermocycling for both groups, amounting to 55% and 95% for the individual adapted posts and the prefabricated posts, respectively. Conclusions: Initially, the samples filled with the individually adapted FRC posts were more resistant to fracture than those filled with the prefabricated ones. However, after ageing of the samples, both types of posts had similar strengthening effects

    Fracture resistance and reinforcement of immature roots with gutta percha, mineral trioxide aggregate and calcium phosphate bone cement: a standardized in vitro model

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    Endodontic treatment of immature teeth is often complicated because of flaring root canals and open apices for which apexification is needed. Long-term prognosis for these teeth is surprisingly low because of cervical root fractures occurring after an impact of weak forces. In this study, an experimental model was developed to determine the fracture resistance of immature teeth and to test the hypothesis that endodontic materials succeed in reinforcing them. Compact and hollow bone cylinders from bovine femurs were used as standardized samples. In order to evaluate the experimental model, fracture resistance in both groups was evaluated by determining the ultimate force to fracture (UFF) under diametral tensile stress. Analysis of variance (ANOVA) revealed a statistically significant difference between the mean values of UFF for both groups, independently of the sampling location or subject. In a following setting, the hypothesis that obturation with gutta percha (GP), mineral trioxide aggregate (MTA), or calcium phosphate bone cement (CPBC) reinforces the hollow bone samples was investigated. Obturation resulted in a significant reinforcement for all materials, but the degree of reinforcement depended on the material. The experimental model appeared to be suitable for in vitro investigation of reinforcement and fracture resistance in a standardized way

    Morphology of corrosion pits in aluminum thin film metallizations

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    Microleakage and penetration of a hydrophilic sealant and a conventional resin-based sealant as a function of preparation techniques: a laboratory study

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    Background. Optimal pit and fissure sealing is determined by surface preparation techniques and choice of materials. Aim. This study aimed (i) to compare the microleakage and penetration depth of a hydrophilic sealant and a conventional resin-based sealant using one of the following preparation techniques: acid etching (AE) only, a diamond bur + AE, and Er:YAG laser combined with AE, and (ii) to evaluate the microleakage and penetration depth of the hydrophilic pit and fissure sealant on different surface conditions. Design. Eighty recently extracted 3rd molars were randomly assigned to eight groups of ten teeth according to the material, preparation technique, and surface condition. For saliva contamination, 0.1 mL of fresh whole human saliva was used. All samples were submitted to 1000 thermal cycles and immersed in 2% methylene blue dye for 4 h. Sections were examined by a light microscope and analysed using image analysis software (Sigmascan (R)). Results. The combination of Er:YAG + AE + conventional sealant showed the least microleakage. The sealing ability of the hydrophilic sealant was influenced by the surface condition. Conclusion. Er:YAG ablation significantly decreased the microleakage at the toothsealant interface compared to the non-invasive technique. The hydrophilic sealant applied on different surface conditions showed
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