Search Results
Trend detection in river flow indices in Poland
The issue of trend detection in long time series of river flow records is of vast theoretical interest and considerable practical relevance. Water management is based on the assumption of stationarity; hence, it is crucial to check whether taking this assumption is justified. The objective of this study is to analyse long-term trends in selected river flow indices in small- and medium-sized catchments with relatively unmodified flow regime (semi-natural catchments) in Poland. The examined indices describe annual and seasonal average conditions as well as annual extreme conditions—low and high flows. The special focus is on the spatial analysis of trends, carried out on a comprehensive, representative data set of flow gauges. The present paper is timely, as no spatially comprehensive studies (i.e. covering the entire Poland or its large parts) on trend detection in time series of river flow have been done in the recent 15 years or so. The results suggest that there is a strong random component in the river flow process, the changes are weak and the spatial pattern is complex. Yet, the results of trend detection in different indices of river flow in Poland show that there exists a spatial divide that seems to hold quite generally for various indices (annual, seasonal, as well as low and high flow). Decreases of river flow dominate in the northern part of the country and increases usually in the southern part. Stations in the central part show mostly ‘no trend’ results. However, the spatial gradient is apparent only for the data for the period 1981–2016 rather than for 1956–2016. It seems also that the magnitude of increases of river flow is generally lower than that of decreases.
Estimating the information gap between textual and visual representations
Photos, drawings, figures, etc. supplement textual information in various kinds of media, for example, in web news or scientific pub- lications. In this respect, the intended effect of an image can be quite different, e.g., providing additional information, focusing on certain details of surrounding text, or simply being a general il- lustration of a topic. As a consequence, the semantic correlation between information of different modalities can vary noticeably, too. Moreover, cross-modal interrelations are often hard to describe in a precise way. The variety of possible interrelations of textual and graphical information and the question, how they can be de- scribed and automatically estimated have not been addressed yet by previous work. In this paper, we present several contributions to close this gap. First, we introduce two measures to describe cross- modal interrelations: cross-modal mutual information (CMI) and semantic correlation (SC). Second, a novel approach relying on deep learning is suggested to estimate CMI and SC of textual and visual information. Third, three diverse datasets are leveraged to learn an appropriate deep neural network model for the demanding task. The system has been evaluated on a challenging test set and the experimental results demonstrate the feasibility of the approach.
A PDF Test-Set for Well-Formedness Validation in JHOVE - The Good, the Bad and the Ugly
Digital preservation and active software stewardship are both cyclical processes. While digital preservation strategies have to be reevaluated regularly to ensure that they still meet technological and organizational requirements, software needs to be tested with every new release to ensure that it functions correctly. JHOVE is an open source format validation tool which plays a central role in many digital preservation workflows and the PDF module is one of its most important features. Unlike tools such as Adobe PreFlight or veraPDF which check against requirements at profile level, JHOVE’s PDF-module is the only tool that can validate the syntax and structure of PDF files. Despite JHOVE’s widespread and long-standing adoption, the underlying validation rules are not formally or thoroughly tested, leading to bugs going undetected for a long time. Furthermore, there is no ground-truth data set which can be used to understand and test PDF validation at the structural level. The authors present a corpus of light-weight files designed to test the validation criteria of JHOVE’s PDF module against “well-formedness”. We conclude by measuring the code coverage of the test corpus within JHOVE PDF validation and by feeding detected inconsistencies of the PDF-module back into the open source development process.
Magnetic properties of GaAs-Fe3Si core-shell nanowires — A comparison of ensemble and single nanowire investigation
On the basis of semiconductor-ferromagnet GaAs-Fe3Si core-shell nanowires (Nws) we compare the facilities of magnetic Nw ensemble measurements by superconducting quantum interference device magnetometry versus investigations on single Nws by magnetic force microscopy and computational micromagnetic modeling. Where a careful analysis of ensemble measurements backed up by transmission electron microscopy gave no insights on the properties of the Nw shells, single Nw investigation turned out to be absolutely essential.
Changes of snow cover in Poland
The present paper examines variability of characteristics of snow cover (snow cover depth, number of days with snow cover and dates of beginning and end of snow cover) in Poland. The study makes use of a set of 43 long time series of observation records from the stations in Poland, from 1952 to 2013. To describe temporal changes in snow cover characteristics, the intervals of 1952–1990 and of 1991–2013 are compared and trends in analysed data are sought (e.g., using the Mann–Kendall test). Observed behaviour of time series of snow-related variables is complex and not easy to interpret, for instance because of the location of the research area in the zone of transitional moderate climate, where strong variability of climate events is one of the main attributes. A statistical link between the North Atlantic Oscillation (NAO) index and the snow cover depth, as well as the number of snow cover days is found.
Beitragsmodell (arXiv)
Auch nach 25 Jahren ist der E-Print-Server arXiv noch immer eine bedeutende Plattform für die schnelle Veröffentlichung von Forschungsergebnissen und we-sentliche Informationsquelle für seine Fachgebiete. arXiv ist zentrales Fachrepo-sitorium und gilt als Prototyp des Open-Access-Publizierens. Dennoch hat Erfolg auch immer seinen Preis: Dieser Beitrag stellt die Informationsplattform arXiv vor und beschreibt die Erfahrungen mit einem Geschäftsmodell, das über Mit-gliedsbeiträge eine nachhaltige Finanzierung erreichen will.
Thermal annealing studies of GeTe-Sb2Te3 alloys with multiple interfaces
A high degree of vacancy ordering is obtained by annealing amorphous GeTe-Sb2Te3 (GST) alloys deposited on a crystalline substrate, which acts as a template for the crystallization. Under annealing the material evolves from amorphous to disordered rocksalt, to ordered rocksalt with vacancies arranged into (111) oriented layers, and finally converts into the stable trigonal phase. The role of the interface in respect to the formation of an ordered crystalline phase is studied by comparing the transformation stages of crystalline GST with and without a capping layer. The capping layer offers another crystallization interface, which harms the overall crystalline quality.
What can we learn from the projections of changes of flow patterns? Results from Polish case studies
River flow projections for two future time horizons and RCP 8.5 scenario, generated by two projects (CHASE-PL and CHIHE) in the Polish-Norwegian Research Programme, were compared. The projects employed different hydrological models over different spatial domains. The semi-distributed, process-based, SWAT model was used in the CHASE-PL project for the entire Vistula and Odra basins area, whilst the lumped, conceptual, HBV model was used in the CHIHE project for eight Polish catchments, for which the comparison study was made. Climate projections in both studies originated from the common EURO-CORDEX dataset, but they were different, e.g. due to different bias correction approaches. Increases in mean annual and seasonal flows were projected in both studies, yet the magnitudes of changes were largely different, in particular for the lowland catchments in the far future. The HBV-based increases were significantly higher in the latter case than the SWAT-based increases in all seasons except winter. Uncertainty in projections is high and creates a problem for practitioners.
Survey: Open Science in Higher Education
Based on a checklist that was developed during a workshop at OER Camp 2016 and presented as a Science 2.0 conference 2016 poster [1], we conducted an online survey among university teachers representing a sufficient variety of subjects. The survey was online from Feb 6th to March 3rd 2017. We got 360 responses, whereof 210 were completes, see raw data [2]. The poster is presented at Open Science Conference, 21.-22.3.2017, Berlin.
Toward light‐regulated living biomaterials
Living materials are an emergent material class, infused with the productive,adaptive, and regenerative properties of living organisms. Property regulation in living materials requires encoding responsive units in the living components to allow external manipulation of their function. Here, an optoregulated Escherichia coli (E. coli)-based living biomaterial that can be externally addressed using light to interact with mammalian cells is demonstrated. This is achieved by using a photoactivatable inducer of gene expression and bacterial surface display technology to present an integrin-specific miniprotein on the outer membrane of an endotoxin-free E. coli strain. Hydrogel surfaces functionalized with the bacteria can expose cell adhesive molecules upon in situ light-activation, and trigger cell adhesion. Surface immobilized bacteria are able to deliver a fluorescent protein to the mammalian cells with which they are interacting, indicating the potential of such a bacterial material to deliver molecules to cells in a targeted manner.