481 research outputs found

    Mapping Europe into local climate zones

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    Cities are major drivers of environmental change at all scales and are especially at risk from the ensuing effects, which include poor air quality, flooding and heat waves. Typically, these issues are studied on a city-by-city basis owing to the spatial complexity of built landscapes, local topography and emission patterns. However, to ensure knowledge sharing and to integrate local-scale processes with regional and global scale modelling initiatives, there is a pressing need for a world-wide database on cities that is suited for environmental studies. In this paper we present a European database that has a particular focus on characterising urbanised landscapes. It has been derived using tools and techniques developed as part of the World Urban Database and Access Portal Tools (WUDAPT) project, which has the goal of acquiring and disseminating climate-relevant information on cities worldwide. The European map is the first major step toward creating a global database on cities that can be integrated with existing topographic and natural land-cover databases to support modelling initiatives

    Crowdsourcing von Lufttemperaturmessdaten zur kleinräumigen Modellierung von städtischen Temperaturverteilungen

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    Methoden und Tools in der Klimaforschung präsentiert von Jungwissenschaftler:innenDie Bereitstellung von atmosphärischen Messdaten über lange Zeiträume mit hoher räumlicher Auflö­sung und Abdeckung stellt eine große Herausforderung in der Klimatologie dar. Dies gilt insbesondere für Städte, da sich Klimamessstationen typischerweise im Außenbereich befinden, sodass das hetero­gene Stadtklima nicht erfasst werden kann. In den letzten Jahren haben sich private Heimwetterstationen (CWS), deren Daten über das Internet abgerufen werden können, weltweit stark verbreitet. Diese Stationen befinden sich vor allem in Städten und können so traditionelle Messnetze ergänzen. CWS, vor allem der Firma "Netatmo", ermöglichen eine räumlich und zeitlich hohe Auflö­sung, jedoch führen inkorrekte Metadaten, ungeeignete Messstandorte und nicht erfasste Positions­änderungen zu fehlerhaften Daten. Während deshalb Daten einzelner Stationen für wissen­schaftliche Analysen ungeeignet sind, erlaubt die ist die große Menge an Daten nach umfänglicher Qualitäts­kontrolle die Beantwortung stadtklimatologischer Fragestellungen. In dieser Bachelorarbeit wurde ein System entwickelt, welches kontinuierlich die Netatmo-Daten für 200 Städte der Welt sammelt. Zur Sicherung der Datenqualität wurde eine Methodik entwickelt, die Positionsänderungen z.B. durch Umzug oder Verkauf erkennt und markiert sowie neue Stationen der Datenbank hinzufügt. Messdaten aktiver Stationen werden monatlich in stündlicher Auflösung mit Extremwerten für die Parameter der Lufttemperatur und -feuchte abgerufen. Für den Großraum Rhein-Ruhr wurden exemplarisch die Daten einer Nacht mit austauscharmer Wetterlage qualitätsgeprüft und mit Verfahren unterschiedlicher Komplexität analysiert. Dazu wurde neben einfachen Interpolationsverfahren auch ein Random Forest Modell trainiert, das auf Basis thermaler und multispektraler Fernerkundungsdaten, eines digitalen Höhenmodells und stadtklimato­logisch relevanter Parametern wie dem Sky View Factor, die Lufttemperatur in 100 m Auflösung modelliert. Solche hochauflösenden Karten der Lufttemperatur könnten beispielsweise dazu verwendet werden, geeignete Orte für wirksame Klimaanpassungsmaßnahmen zu identifizieren. Die Datenbank bietet zudem eine Grundlage für weitere Untersuchungen und kann unmittelbar größere Mengen auf crowdsourcing basierender Daten mit gesicherten Metadaten bereitstellen

    Fourteen years' experience with 501 subcoronary Ross procedures: Surgical details and results

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    ObjectiveDuring the past decade the Ross procedure using the full root has become the predominant surgical technique. However, progressive autograft dilatation and eventual failure remain a concern. Here we report on the surgical techniques and results of the subcoronary technique over a 14-year period.MethodsA total of 501 patients (mean age, 44.9 ± 12.9 years; 117 female; 384 male) were operated on from June 1994 to December 2007. The follow-up database, with a completeness of 98.2%, was closed on December 2008, comprising of 2931 patient-years with a mean follow-up of 5.9 ± 3.6 years (range, 0.1–14.1 years).ResultsSurgical details are presented. Early and late mortality were 0.4% (n = 2) and 4% (n = 20), respectively, valve-related mortality was 1.2% (n = 6), whereas the overall survival did not differ from that of the normal population. Neurologic events occurred in 22 patients, major bleeding in 9, autograft endocarditis in 8, and homograft endocarditis in 10. Freedom from autograft and homograft reoperation was 91.9% at 10 years. For the majority of patients, hemodynamics was excellent and no root dilatation was observed.ConclusionsMidterm results after the original subcoronary Ross procedure are excellent, including normal survival and low risk of valve-related morbidity. Longer-term results are necessary for continuous judgment of the subcoronary technique

    CrowdQC+—A Quality-Control for Crowdsourced Air-Temperature Observations Enabling World-Wide Urban Climate Applications

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    In recent years, the collection and utilisation of crowdsourced data has gained attention in atmospheric sciences and citizen weather stations (CWS), i.e., privately-owned weather stations whose owners share their data publicly via the internet, have become increasingly popular. This is particularly the case for cities, where traditional measurement networks are sparse. Rigorous quality control (QC) of CWS data is essential prior to any application. In this study, we present the QC package “CrowdQC+,” which identifies and removes faulty air-temperature (ta) data from crowdsourced CWS data sets, i.e., data from several tens to thousands of CWS. The package is a further development of the existing package “CrowdQC.” While QC levels and functionalities of the predecessor are kept, CrowdQC+ extends it to increase QC performance, enhance applicability, and increase user-friendliness. Firstly, two new QC levels are introduced. The first implements a spatial QC that mainly addresses radiation errors, the second a temporal correction of the data regarding sensor-response time. Secondly, new functionalities aim at making the package more flexible to apply to data sets of different lengths and sizes, enabling also near-real time application. Thirdly, additional helper functions increase user-friendliness of the package. As its predecessor, CrowdQC+ does not require reference meteorological data. The performance of the new package is tested with two 1-year data sets of CWS data from hundreds of “Netatmo” CWS in the cities of Amsterdam, Netherlands, and Toulouse, France. Quality-controlled data are compared with data from networks of professionally-operated weather stations (PRWS). Results show that the new package effectively removes faulty data from both data sets, leading to lower deviations between CWS and PRWS compared to its predecessor. It is further shown that CrowdQC+ leads to robust results for CWS networks of different sizes/densities. Further development of the package could include testing the suitability of CrowdQC+ for other variables than ta, such as air pressure or specific humidity, testing it on data sets from other background climates such as tropical or desert cities, and to incorporate added filter functionalities for further improvement. Overall, CrowdQC+ could lead the way to utilise CWS data in world-wide urban climate applications.DFG, 437467569, ENLIGHT – ENabling the anaLysIs of Global urban Hea

    A Case of Severe Aortic Valve Regurgitation Caused by an Ascending Aortic Aneurysm in a Young Patient With Autosomal Dominant Polycystic Kidney Disease and Normal Renal Function

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    Aortic aneurysm is one several well-known cardiovascular complications in patients with autosomal dominant polycystic kidney disease (ADPCKD). Commonly affected site of aortic aneurysm and its related dissection in ADPCKD is abdominal aorta. Long standing hypertension, haemodialysis, old age are closely related with discovering of aortic aneurysm and dissection in ADPCKD. However, thoracic aortic aneurysms and its related severe aortic regurgitations (ARs) are rare in younger patients suffering from ADPCKD, especially ones who have normal renal function. Here, we report a case involving a 27-year-old Asian male patient with severe AR due to an ascending aneurysm of the thoracic aorta associated with ADPCKD. The patient had normal renal function without Marfan's habitus. The AR and thoracic aortic aneurysm were corrected surgically

    Osvrti na publikacije

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    The World Urban Database and Access Portal Tools (WUDAPT) is a community initiative to collect worldwide data on urban form (i.e., morphology, materials) and function (i.e., use and metabolism). This is achieved through crowdsourcing, which we define here as the collection of data by a bounded crowd, composed of students. In this process, training data for the classification of urban structures into Local Climate Zones (LCZ) are obtained, which are, like most volunteered geographic information initiatives, of unknown quality. In this study, we investigated the quality of 94 crowdsourced training datasets for ten cities, generated by 119 students from six universities. The results showed large discrepancies and the resulting LCZ maps were mostly of poor to moderate quality. This was due to general difficulties in the human interpretation of the (urban) landscape and in the understanding of the LCZ scheme. However, the quality of the LCZ maps improved with the number of training data revisions. As evidence for the wisdom of the crowd, improvements of up to 20% in overall accuracy were found when multiple training datasets were used together to create a single LCZ map. This improvement was greatest for small training datasets, saturating at about ten to fifteen sets
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