951 resultados para Air-sea interactions


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Exposure to outdoor air pollutants and passive tobacco smoke are common but avoidable worldwide risk factors for morbidity and mortality of individuals. In addition to well-known effects of pollutants on the cardiovascular system and the development of cancer, in recent years the association between air pollution and respiratory morbidity has become increasingly apparent. Not only in adults, but also in children with asthma and in healthy children a clear harmful effect of exposure towards air pollutants has been demonstrated in many studies. Among others increased pollution has been shown to result in more frequent and more severe respiratory symptoms, more frequent exacerbations, higher need for asthma medication, poorer lung function and increased visits to the emergency department and more frequent hospitalisations. While these associations are well established, the available data on the role of air pollution in the development of asthma seems less clear. Some studies have shown that increased exposure towards tobacco smoke and air pollution leads to an increase in asthma incidence and prevalence; others were not able to confirm those findings. Possible reasons for this discrepancy are different definitions of the outcome asthma, different methods for exposure estimation and differences in the populations studied with differing underlying genetic backgrounds. Regardless of this inconsistency, several mechanisms have already been identified linking air pollution with asthma development. Among these are impaired lung growth and development, immunological changes, genetic or epigenetic effects or increased predisposition for allergic sensitisation. What the exact interactions are and which asthmatic phenotypes will be influenced most by pollutants will be shown by future studies. This knowledge will then be helpful in exploring possible preventive measures for the individual and to help policy makers in deciding upon most appropriate regulations on a population level.

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The Arctic sea ice cover declined over the last few decades and reached a record minimum in 2007, with a slight recovery thereafter. Inspired by this the authors investigate the response of atmospheric and oceanic properties to a 1-yr period of reduced sea ice cover. Two ensembles of equilibrium and transient simulations are produced with the Community Climate System Model. A sea ice change is induced through an albedo change of 1 yr. The sea ice area and thickness recover in both ensembles after 3 and 5 yr, respectively. The sea ice anomaly leads to changes in ocean temperature and salinity to a depth of about 200 m in the Arctic Basin. Further, the salinity and temperature changes in the surface layer trigger a “Great Salinity Anomaly” in the North Atlantic that takes roughly 8 yr to travel across the North Atlantic back to high latitudes. In the atmosphere the changes induced by the sea ice anomaly do not last as long as in the ocean. The response in the transient and equilibrium simulations, while similar overall, differs in specific regional and temporal details. The surface air temperature increases over the Arctic Basin and the anomaly extends through the whole atmospheric column, changing the geopotential height fields and thus the storm tracks. The patterns of warming and thus the position of the geopotential height changes vary in the two ensembles. While the equilibrium simulation shifts the storm tracks to the south over the eastern North Atlantic and Europe, the transient simulation shifts the storm tracks south over the western North Atlantic and North America. The authors propose that the overall reduction in sea ice cover is important for producing ocean anomalies; however, for atmospheric anomalies the regional location of the sea ice anomalies is more important. While observed trends in Arctic sea ice are large and exceed those simulated by comprehensive climate models, there is little evidence based on this particular model that the seasonal loss of sea ice (e.g., as occurred in 2007) would constitute a threshold after which the Arctic would exhibit nonlinear, irreversible, or strongly accelerated sea ice loss. Caution should be exerted when extrapolating short-term trends to future sea ice behavior.

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In spite of the environmental relevance of 129I, there is still a scarcity of data about its presence in the different natural compartments. In this work, results are presented on the concentration of 129I in rainwater samples taken in Sevilla (southwestern Spain) and in a sediment core taken near the Ringhals coast (Sweden). Typical concentrations of 108 and 109129I at/l are found in rainwater samples, similar to other values in literature. In the case of the sediment core, our results clearly show the impact of anthropogenic sources, with concentrations in the order of 1013129I at./kg and isotopic ratios 129I/127I in the order of 10−8 in the higher layers.

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A 37-year-old man presented with a 4-day history of nonbloody diarrhea, fever, chills, productive cough, vomiting, and more recent sore throat. He worked for the municipality in a village in the Swiss Alps near St. Moritz. Examination showed fever (40 °C), hypotension, tachycardia, tachypnea, decreased oxygen saturation (90 % at room air), and bibasilar crackles and wheezing. Chest radiography and computed tomography scan showed an infiltrate in the left upper lung lobe. He responded to empiric therapy with imipenem for 5 days. After the imipenem was stopped, the bacteriology laboratory reported that 2/2 blood cultures showed growth of Francisella tularensis. He had recurrence of fever and diarrhea. He was treated with ciprofloxacin (500 mg twice daily, oral, for 14 days) and symptoms resolved. Further testing confirmed that the isolate was F. tularensis (subspecies holarctica) belonging to the subclade B.FTNF002-00 (Western European cluster). This case may alert physicians that tularemia may occur in high-altitude regions such as the Swiss Alps.

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This paper discusses the theological and cultural exchanges between Catholic clergy and theologians, and specifically between the neo-Augustinian-minded, the so-called “Jansenists”, and other Catholics, in Northern Europe during the seventeenth century. It also explores the Jansenists’ encounters and theological engagement with Protestantism. In this period, interaction and transfer between French Jansenist Catholics and other Catholics in other countries took place in various ways: 1. Via traveling and migration: French theologians and clergy returned home from their travels with reports about the situation of Catholicism and Protestantism in other countries; moreover, in the second half of the 17th century, French Jansenists fled to the northern Netherlands. 2. Via networking: it is little known that for a brief period on the North Sea island of Nordstrand, adherents to Port-Royal were buying land, and clergy of the Flemish Oratory provided pastoral care for the island’s Catholics. This project was not successful, but at the end it strengthened the network between French “Jansenists” and Catholics in the Dutch Republic. 3. Via publications by leading Jansenists and their counterparts. In this paper, the focus is on the view of Protestantism held by Jansenist writers.

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Lake Butrint (39°47 N, 20°1 E) is a ca. 21 m deep, coastal lagoon located in SW Albania where finely-laminated sediments have been continuously deposited during the last millennia. The multi-proxy analysis (sedimentology, high-resolution elemental geochemistry and pollen) of a 12 m long sediment core, supported by seven AMS radiocarbon dates and 137Cs dating, enable a precise reconstruction of the environmental change that occurred in the central Mediterranean region during the last ∼4.5 cal kyrs BP. Sediments consist of triplets of authigenic carbonates, organic matter and clayey laminae. Fluctuations in the thickness and/or presence of these different types of seasonal laminae indicate variations in water salinity, organic productivity and runoff in the lake's catchment, as a result of the complex interplay of tectonics, anthropogenic forcing and climate variability. The progradation of the Pavllo river delta, favoured by variable human activity from the nearby ancient city of Butrint, led to the progressive isolation of this hydrological system from the Ionian Sea. The system evolved from an open bay to a restricted lagoon, which is consistent with archaeological data. An abrupt increase in mass-wasting activity between 1515 and 1450 BC, likely caused by nearby seismic activity, led to the accumulation of 24 homogenites, up to 17 cm thick. They have been deposited during the onset of finely laminated sedimentation, which indicates restricted, anoxic bottom water conditions and higher salinity. Periods of maximum water salinity, biological productivity, and carbonate precipitation coincide with warmer intervals, such as the early Roman Warm Period (RWP) (500 BC–0 AD), the Medieval Climate Anomaly (MCA) (800–1400 AD) and recent times (after 1800 AD). Conversely, lower salinity and more oxic conditions, with higher clastic input were recorded during 1400–500 BC, the Late Roman and the Early Medieval periods (0–800 AD) and during the Little Ice Age (1400–1800 AD). Hydrological fluctuations recorded in Butrint are in phase with most central and western Mediterranean records and correlate with NAO variability. In contrast, opposite hydrological patterns have been recorded in the Eastern Balkans and the Levant during the last millennium, emphasizing a complex spatial variability in the region. Phases of maximum settlement intensity in Butrint (Roman-Late Antique) coincide with warmer and/or stable climate periods (0–800 AD and MCA, respectively), indicating a long-term influence of climatic conditions on human activities. The Late Holocene sedimentary record of Lake Butrint demonstrates the complex interplay of climate variability, tectonics and human impact in the recent evolution of coastal Mediterranean regions.