Investigating drivers and dynamics of hot and dry extremes in Europe by applying machine learning approaches

Heatwaves and droughts are increasingly impacting our ecosystem, infrastructure and society through their rising intensity and frequency due to the present effect of global warming. A series of recent extreme heatwaves and droughts in Europe, like in 2003, 2006, 2018 and 2022, have revealed the vulnerability by causing various impacts from increased heat stress on humans and the ecosystem to missing cooling water for thermal power plants and increased incidence of climate- sensitive diseases. The frequency and intensity of heatwaves and droughts are expected to increase in most regions of Europe in the upcoming years. This thesis studies the predictability and interrelationship of heatwaves and droughts and their evolution with climate change by applying different machine learning techniques. With the help of artificial intelligence methods such as ANN and hierarchical agglomerative clustering, the study advances the scientific knowledge on the predictability of droughts. The thesis shows that air pressure and teleconnection indices are essential predictors for droughts in Munich and Lisbon, as well as that for Northern Europe number of heatwave days in summer, can serve as a predictor for an agricultural drought in fall. For summer heatwaves in South Europe, the soil moisture deficit in the previous spring can serve as a predictor. The thesis shows that compound hot and dry events will become more probable with rising Global Warming Levels in most European regions. At the same time, there is a difference of up to five to six times in event occurrence when comparing GWL +2K to GWL +3K, underlining the benefits of sticking to a two-degree target. This scientific knowledge is valuable for further studies on the predictability of hot and dry events. The evolution in the future is valuable for decision-makers for implementation of mitigation measures to address the impacts of these events on human health, agriculture, and the environment

The structure and possible origins of stacking faults in gamma-yttrium disilicate

Parallel stacking faults on (010) planes are frequently observed in hot-pressed Y2Si2O7. A combination of conventional dark-field imaging and high-resolution transmission electron microscopy was used to investigate the structure of these faults and it was found that they consist of the repeat of one layer of the two layer γ-Y2Si2O7 structure with an associated in-plane rigid body displacement. The resulting structure was confirmed by image simulation of high-resolution images from two perpendicular projections. A model for the formation of the stacking faults is proposed as a consequence of a transformation from β-Y2Si2O7 to γ-Y2Si2O7 in the hot pressing

Coupling Analysis Between Twitter and Call Centre

Social media has been contributing many research areas such as data mining, recommender systems, time series analysis, etc. However, there are not many successful applications regarding social media in government agencies. In fact, lots of governments have social media accounts such as twitter and facebook. More and more customers are likely to communicate with governments on social media, causing massive external social media data for governments. This external data would be beneficial for analysing behaviours and real needs of the customers. Besides this, most governments also have a call centre to help customers solve their problems. It is not difficult to imagine that the enquiries on external social media and internal call centre may have some coupling relationships. The couplings could be helpful for studying customers' intent and allocating government's limited resources for better service. In this paper, we mainly focus on analysing the coupling relations between internal call centre and external public media using time series analysis methods for Australia Department of Immigration and Border Protec-tion. The discovered couplings demonstrate that call centre and public media indeed have correlations, which are significant for understanding customers' behaviours

Kristalline Phasen und Fluoreszenz der Gläser im System Li2O-Tb2O3-SiO2

Bei den Seltenerd-Lithiumsilicatgläsern zeigen terbiumhaltige Gläser bei Röntgen- und UV-Anregung eine außergewöhnlich starke Fluoreszenz bei 550 und 495 nm, wobei die Intensität dieses grünlichen Leuchtens von der thermischen Vorgeschichte des Glases abhängt. In der vorliegenden Arbeit wird diese Erscheinung in bezug auf mögliche Wechsel im Sauerstoffnahordnungsbereich um das Terbiumion diskutiert, und es werden mögliche Sauerstoffkonfigurationen einiger kristalliner Verbindungen abgeleitet. Es werden charakteristische kristallografische Daten und die entsprechenden Fluoreszenzspektren angegeben

How can I find what I want? Can children, chimpanzees and capuchin monkeys form abstract representations to guide their behavior in a sampling task?

Authors are grateful to the Royal Zoological Society of Scotland (RZSS) and the University of St Andrews for core financial support to the RZSS Edinburgh Zoo’s Living Links Research Centre, where this project was carried out. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement No. [639072]). We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada (NSERC) [funding reference number 2016-05552].Abstract concepts are a powerful tool for making wide-ranging predictions in new situations based on little experience. Whereas looking-time studies suggest an early emergence of this ability in human infancy, other paradigms like the relational match to sample task often fail to detect abstract concepts until late preschool years. Similarly, non-human animals show difficulties and often succeed only after long training regimes. Given the considerable influence of slight task modifications, the conclusiveness of these findings for the development and phylogenetic distribution of abstract reasoning is debated. Here, we tested the abilities of 3 to 5-year-old children, chimpanzees, and capuchin monkeys in a unified and more ecologically valid task design based on the concept of “overhypotheses” (Goodman, 1955). Participants sampled high- and low-valued items from containers that either each offered items of uniform value or a mix of high- and low-valued items. In a test situation, participants should switch away earlier from a container offering low-valued items when they learned that, in general, items within a container are of the same type, but should stay longer if they formed the overhypothesis that containers bear a mix of types. We compared each species' performance to the predictions of a probabilistic hierarchical Bayesian model forming overhypotheses at a first and second level of abstraction, adapted to each species' reward preferences. Children and, to a more limited extent, chimpanzees demonstrated their sensitivity to abstract patterns in the evidence. In contrast, capuchin monkeys did not exhibit conclusive evidence for the ability of abstract knowledge formation.Publisher PDFPeer reviewe

Nitrido-Sodalithe. I Synthese, Struktur und Eigenschaften von Zn7-xH2x[P12N24]Cl2 mit 0 <x< 3

Die Nitrido-Sodalithe Zn7-xH2x[P12N24]Cl2 mit 0 x 3 wurden durch heterogene Druckammonolyse von P3N5 in Gegenwart von ZnCl2 (T = 650°C) dargestellt. Die Verbindungen sind auch zugänglich durch Umsetzung von ZnCl2, (PNCl2)3 und NH4Cl bei 700°C. Die Kristallstrukturen von vier ausgewählten Vertretern der obigen Verbindungsreihe wurden auf der Basis von Röntgen-Pulverdiffraktometerdaten mit Hilfe der Rietveld-Methode verfeinert (I3m, a = 821,61(4) bis 824,21(1) pm, Z = 1). Im Festkörper liegt eine dreidimensionale Gerüststruktur allseitig eckenverknüpfter PN4-Tetraeder vor (PN: 163,6 pm, PNP: 125,6°, Mittelwerte), die dem Sodalith-Typ entspricht. Im Zentrum der -Käfige befinden sich Cl--Ionen, die ihrerseits tetraedrisch durch Zn2+-Ionen umgeben sind. Die Zn2+-Positionen sind statistisch besetzt und gemäß der angegebenen Phasenbreite (0 x 3) kann ein Teil der Zn2+-Ionen durch jeweils zwei H-Atome ersetzt werden, die ihrerseits kovalent an Stickstoffatome des PN-Gerüstes gebunden sind. Im IR-Spektrum der Verbindungen werden charakteristische Schwingungsbanden beobachtet

The structure of executive functions in preschool children and chimpanzees

Executive functions (EF) are a core aspect of cognition. Research with adult humans has produced evidence for unity and diversity in the structure of EF. Studies with preschoolers favour a 1-factor model, in which variation in EF tasks is best explained by a single underlying trait on which all EF tasks load. How EF are structured in nonhuman primates remains unknown. This study starts to fill this gap through a comparative, multi-trait multi-method test battery with preschoolers (N = 185) and chimpanzees (N = 55). The battery aimed at measuring working memory updating, inhibition, and attention shifting with three non-verbal tasks per function. For both species the correlations between tasks were low to moderate and not confined to tasks within the same putative function. Factor analyses produced some evidence for the unity of executive functions in both groups, in that our analyses revealed shared variance. However, we could not conclusively distinguish between 1-, 2- or 3-factor models. We discuss the implications of our findings with respect to the ecological validity of current psychometric research