1,287 research outputs found

    Extreme weather and climate events with ecological relevance : a review

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    Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Philosophical Transactions of the Royal Society of London.Series B, Biological Sciences, 372 (2017): 2016.0135, doi: 10.1098/rstb.2016.0135.Robust evidence exists that certain extreme weather and climate events, especially daily temperature and precipitation extremes, have changed in regard to intensity and frequency over recent decades. These changes have been linked to human-induced climate change, while the degree to which climate change impacts an individual extreme climate event (ECE) is more difficult to quantify. Rapid progress in event attribution has recently been made through improved understanding of observed and simulated climate variability, methods for event attribution and advances in numerical modelling. Attribution for extreme temperature events is stronger compared with other event types, notably those related to the hydrological cycle. Recent advances in the understanding of ECEs, both in observations and their representation in state-of-the-art climate models, open new opportunities for assessing their effect on human and natural systems. Improved spatial resolution in global climate models and advances in statistical and dynamical downscaling now provide climatic information at appropriate spatial and temporal scales. Together with the continued development of Earth System Models that simulate biogeochemical cycles and interactions with the biosphere at increasing complexity, these make it possible to develop a mechanistic understanding of how ECEs affect biological processes, ecosystem functioning and adaptation capabilities. Limitations in the observational network, both for physical climate system parameters and even more so for long-term ecological monitoring, have hampered progress in understanding bio-physical interactions across a range of scales. New opportunities for assessing how ECEs modulate ecosystem structure and functioning arise from better scientific understanding of ECEs coupled with technological advances in observing systems and instrumentation.Portions of this study were supported by the Regional and Global Climate Modeling Program (RGCM) of the U.S. Department of Energy's Office of Biological & Environmental Research (BER) Cooperative Agreement #DE-FC02-97ER62402, and the National Science Foundation

    CAM-Convs: Camera-Aware Multi-Scale Convolutions for Single-View Depth

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    Single-view depth estimation suffers from the problem that a network trained on images from one camera does not generalize to images taken with a different camera model. Thus, changing the camera model requires collecting an entirely new training dataset. In this work, we propose a new type of convolution that can take the camera parameters into account, thus allowing neural networks to learn calibration-aware patterns. Experiments confirm that this improves the generalization capabilities of depth prediction networks considerably, and clearly outperforms the state of the art when the train and test images are acquired with different cameras.Comment: Camera ready version for CVPR 2019. Project page: http://webdiis.unizar.es/~jmfacil/camconvs

    Ausbildung von Rettungspersonal: Worin und wozu?

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    Zusammenfassung: Für viele an und für sich akzeptierte Interventionen in der Notfallmedizin fehlt die wissenschaftliche Evidenz. Das erschwert zwangsläufig die Ausbildungsinhalte des eingesetzten Personals. Rettungssanitäter werden in der Schweiz in allen lebensrettenden Basismaßnahmen ausgebildet, können aber in delegierter Kompetenz auch gewisse ärztliche Interventionen ausführen. Für Notärzte gilt, dass nur erfahrene und gut ausgebildete Kliniker im Rahmen eines strukturierten Weiterbildungsprogramms, respektive nach dessen Abschluss zum Einsatz kommen sollen, was dann aufgrund ihrer Entscheidungskompetenz und Teamleitungsfunktion auch in ethischen Spannungsfeldern vorteilhaft is

    Intraseasonal rainfall variability in the Bay of Bengal during the Summer Monsoon: coupling with the ocean and modulation by the Indian Ocean Dipole

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    The Indian Summer Monsoon rainfall exhibits pronounced intraseasonal variability in the Bay of Bengal (BoB). This study examines the intraseasonal rainfall variability with foci on the coupling with sea surface temperatures (SST) and its interannual modulation. The lagged composite analysis reveals that, in the northern BoB, SST warming leads the onset of intraseasonal rainfall by 5 days. Latent heat flux is reduced before the rain event but is greatly amplified during the rainfall maxima. Further analysis reveals that this intraseasonal rainfall-SST relationship through latent heating is strengthened in negative Indian Ocean Dipole (IOD) years when the bay-wide local SST is anomalously warm. Latent heat flux is further increased during the intraseasonal rainfall maxima leading to strengthened rainfall variability. The moisture budget analysis shows this is primarily due to stronger low-level moisture convergence in negative IOD years. The results provide important predictive information on the monsoon rainfall and its active/break cycles

    Management of acute respiratory distress syndrome using pumpless extracorporeal lung assist

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    Purpose: To describe the use of a pumpless extracorporeal lung assist device in the treatment of severe acute respiratory distress syndrome (ARDS). Clinical features: A 15-yr-old girl developed severe post-traumatic ARDS. After all conventional treatment strategies failed, we inserted a pumpless extracorporeal lung assist device. This device consists of an arterial cannula inserted into the femoral artery, and a membrane oxygenator with a venous cannula that returns the oxygenated blood back to the patient's femoral vein. Since the driving force is the patient's blood pressure, a roller pump with its negative side effects is not needed. The device allowed removal of excessive PaCO2 and, by applying minimal ventilation, minimization of further ventilator-induced lung injury. The pumpless extracorporeal lung assist device remainedin situ for ten days without any adverse side effect. During this time, the lung recovered such that mechanical ventilation could be reinstalled cautiously. The device was then removed and, after a prolonged period of intensive care, the patient recovered without any sequelae. Conclusion: In this case of a severely damaged lung, an arteriovenous pumpless extracorporeal lung assist was a helpful device to remove elevated CO2 and reduce mechanical stress by applying minimal ventilation. This device is simple to operate and has the potential of being used routinely in the treatment of severe ARD

    The role of the subtropical North Atlantic water cycle in recent US extreme precipitation events

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Climate Dynamics 50 (2018): 1291–1305, doi:10.1007/s00382-017-3685-y.The role of the oceanic water cycle in the record-breaking 2015 warm-season precipitation in the US is analyzed. The extreme precipitation started in the Southern US in the spring and propagated northward to the Midwest and the Great Lakes in the summer of 2015. This seasonal evolution of precipitation anomalies represents a typical mode of variability of US warm-season precipitation. Analysis of the atmospheric moisture flux suggests that such a rainfall mode is associated with moisture export from the subtropical North Atlantic. In the spring, excessive precipitation in the Southern US is attributable to increased moisture flux from the northwestern portion of the subtropical North Atlantic. The North Atlantic moisture flux interacts with local soil moisture which enables the US Midwest to draw more moisture from the Gulf of Mexico in the summer. Further analysis shows that the relationship between the rainfall mode and the North Atlantic water cycle has become more significant in recent decades, indicating an increased likelihood of extremes like the 2015 case. Indeed, two record-high warm-season precipitation events, the 1993 and 2008 cases, both occurred in the more recent decades of the 66 year analysis period. The export of water from the North Atlantic leaves a marked surface salinity signature. The salinity signature appeared in the spring preceding all three extreme precipitation events analyzed in this study, i.e. a saltier-than-normal subtropical North Atlantic in spring followed by extreme Midwest precipitation in summer. Compared to the various sea surface temperature anomaly patterns among the 1993, 2008, and 2015 cases, the spatial distribution of salinity anomalies was much more consistent during these extreme flood years. Thus, our study suggests that preseason salinity patterns can be used for improved seasonal prediction of extreme precipitation in the Midwest.LL is supported by the Postdoctoral Scholar Program at WHOI, with funding provided by the Oceans and Climate Change Institute. RWS is supported by NASA Grants NNX12AF59G and NNX14AH38G, and NSF Grant OCE-1129646. CCU is supported by NSF Grant AGS-1355339

    North Atlantic natural variability modulates emergence of widespread Greenland melt in a warming climate

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    Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 45 (2018): 9171-9178, doi:10.1029/2018GL079682.Record‐breaking melt over Greenland in recent decades is linked not only to climate change but also to natural variability, including persistent atmospheric high‐pressure conditions in the negative phase of the North Atlantic Oscillation and warm North Atlantic Ocean temperatures during the positive phase of the Atlantic Multidecadal Oscillation. However, the relative importance of natural variability for Greenland melt under varying degrees of greenhouse forcing is still unclear. Using reanalysis data and a large ensemble of climate model simulations, we find that a negative North Atlantic Oscillation and positive Atlantic Multidecadal Oscillation consistently promote heightened summer melt under various forcing conditions. Moreover, timing of widespread 21st century Greenland melt varies considerably between ensemble members due to different phasing of these modes of natural variability. These results indicate the importance of natural modes of variability across a range of external forcing conditions for interannual melt variability and the emergence of widespread Greenland melt.U.S. National Science Foundation Grant Number: ANS‐1736738; Woods Hole Oceanographic Institution Summer Student Fellow program Grant Number: AGS‐13553392019-03-1

    Hydroclimate variability from western Iberia (Portugal) during the Holocene: insights from a composite stalagmite isotope record

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Thatcher, D. L., Wanamaker, A. D., Denniston, R. F., Asmerom, Y., Polyak, V. J., Fullick, D., Ummenhofer, C. C., Gillikin, D. P., & Haws, J. A. Hydroclimate variability from western Iberia (Portugal) during the Holocene: insights from a composite stalagmite isotope record. Holocene, (2020): 095968362090864, doi:10.1177/0959683620908648.Iberia is predicted under future warming scenarios to be increasingly impacted by drought. While it is known that this region has experienced multiple intervals of enhanced aridity over the Holocene, additional hydroclimate-sensitive records from Iberia are necessary to place current and future drying into a broader perspective. Toward that end, we present a multi-proxy composite record from six well-dated and overlapping speleothems from Buraca Gloriosa (BG) cave, located in western Portugal. The coherence between the six stalagmites in this composite stalagmite record illustrates that climate (not in-cave processes) impacts speleothem isotopic values. This record provides the first high-resolution, precisely dated, terrestrial record of Holocene hydroclimate from west-central Iberia. The BG record reveals that aridity in western Portugal increased secularly from 9.0 ka BP to present, as evidenced by rising values of both carbon (δ13C) and oxygen (δ18O) stable isotope values. This trend tracks the decrease in Northern Hemisphere summer insolation and parallels Iberian margin sea surface temperatures (SST). The increased aridity over the Holocene is consistent with changes in Hadley Circulation and a southward migration of the Intertropical Convergence Zone (ITCZ). Centennial-scale shifts in hydroclimate are coincident with changes in total solar irradiance (TSI) after 4 ka BP. Several major drying events are evident, the most prominent of which was centered around 4.2 ka BP, a feature also noted in other Iberian climate records and coinciding with well-documented regional cultural shifts. Substantially, wetter conditions occurred from 0.8 ka BP to 0.15 ka BP, including much of the ‘Little Ice Age’. This was followed by increasing aridity toward present day. This composite stalagmite proxy record complements oceanic records from coastal Iberia, lacustrine records from inland Iberia, and speleothem records from both northern and southern Spain and depicts the spatial and temporal variability in hydroclimate in Iberia.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported, in part, by the US National Science Foundation (Grants: #1804528 to ADW; #1804635 to RD; #1804132 to CCU; #1806025 to YA and VP; #1805163 to DPG; BCS-0455145, BCS-0612923, and BCS-1118155 to JAH)

    DeMoN: Depth and Motion Network for Learning Monocular Stereo

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    In this paper we formulate structure from motion as a learning problem. We train a convolutional network end-to-end to compute depth and camera motion from successive, unconstrained image pairs. The architecture is composed of multiple stacked encoder-decoder networks, the core part being an iterative network that is able to improve its own predictions. The network estimates not only depth and motion, but additionally surface normals, optical flow between the images and confidence of the matching. A crucial component of the approach is a training loss based on spatial relative differences. Compared to traditional two-frame structure from motion methods, results are more accurate and more robust. In contrast to the popular depth-from-single-image networks, DeMoN learns the concept of matching and, thus, better generalizes to structures not seen during training.Comment: Camera ready version for CVPR 2017. Supplementary material included. Project page: http://lmb.informatik.uni-freiburg.de/people/ummenhof/depthmotionnet

    Ethische Kompetenz im Rettungsdienst: Ausbildung professioneller Helfer - Ergebnisse einer Interviewstudie in Basel

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    Zusammenfassung: Fragestellung: Ziel der Studie war es, die ethischen Dimensionen von Reanimationsentscheidungen im Rettungsdienst zu untersuchen. Methode: Ein qualitatives Studiendesign wurde entwickelt, um ethische Entscheidungskriterien, persönliche Wertvorstellungen und Bedarf an Aus- und Weiterbildung zu erfragen. Mit Rettungsdienstmitarbeitern in Basel wurden 30 strukturierte Interviews geführt und nach der qualitativen Inhaltsanalyse ausgewertet. Ergebnisse: Notärzte und Rettungssanitäter beziehen eine Vielzahl ethischer Überlegungen in ihre Entscheidungen mit ein. Die Mehrheit äußerte Interesse an ethischer Schulung oder forderte sogar eine stärkere Verankerung ethischer Inhalte in Aus- und Weiterbildung. Schlussfolgerung: Konzepte für die Vermittlung medizinischer Ethik sollten den Bedürfnissen professioneller Helfer und den besonderen Gegebenheiten des Rettungsdienstes Rechnung trage
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