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  • 2020-2024  (1)
  • 2020-2022  (13)
  • 1
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    Arctic Observing Summit
    In:  EPIC3Arctic Observing Summit, online, 2020-03-31-2020-04-02Arctic Observing Summit
    Publication Date: 2020-11-26
    Description: Arctic permafrost coasts are major carbon (Schuur et al., 2015) and mercury pools (Schuster et al., 2018). They represent about 34% of the Earth’s coastline, with long sections affected by high erosion rates (Fritz et al, 2017), increasingly threatening coastal communities. Year-round reduction in Arctic sea ice is forecasted and by the end of the 21st century, models indicate a decrease in sea ice area from 43 to 94% in September and from 8 to 34% in February (IPCC, 2014). An increase of the sea-ice free season leads to a longer exposure of coasts to wave action. Further, climate warming is also expected to modify the contribution of terrestrial erosion (Fritz et al., 2015, Ramage et al., 2018, Irrgang et al., 2018). Within the project EU Horizon2020 project NUNATARYUK, we are updating the mapping of the Arctic coast, with the Canadian Beaufort coast as a case-study. The surveying methodology includes: i. a high resolution update of the coastline mapping and change rates using Pleiades (CNES) satellite acquisitions from 2018, ii. a survey using RTK-UAV aerial imagery of long-term monitoring sites from the Canada-US border to King Point, and iii. the experimental use of TerraSAR-X staring spotlight scenes at key sites to monitor intraseasonal dynamics of cliff edge retreat. This research is funded by the EC H2020 Project NUNATARYUK. Support on remote sensing imagery access by the WMO Polar Space Task Group.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev , info:eu-repo/semantics/conferenceObject
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  • 2
    Publication Date: 2021-02-28
    Description: Permafrost coasts make up roughly one third of all coasts worldwide. Their erosion leads to the release of previously locked organic carbon, changes in ecosystems and the destruction of cultural heritage, infrastructure and whole communities. Since rapid environmental changes lead to an intensification of Arctic coastal dynamics, it is of great importance to adequately quantify current and future coastal changes. However, the remoteness of the Arctic and scarcity of data limit our understanding of coastal dynamics at a pan-Arctic scale and prohibit us from getting a complete picture of the diversity of impacts on the human and natural environment. In a joint effort of the EU project NUNATARYUK and the NSF project PerCS-Net, we seek to close this knowledge gap by collecting and analyzing all accessible high-resolution shoreline position data for the Arctic coastline. These datasets include geographical coordinates combined with coastal positions derived from archived data, surveying data, air and space born remote sensing products, or LiDAR products. The compilation of this unique dataset will enable us to reach unprecedented data coverage and will allow us a first insight into the magnitude and trends of shoreline changes on a pan-Arctic scale with locally highly resolved temporal and spatial changes in shoreline dynamics. By comparing consistently derived shoreline change data from all over the Arctic we expect that the trajectory of coastal change in the Arctic becomes evident. A synthesis of some initial results will be presented in the 2020 Arctic Report Card on Arctic Coastal Dynamics. This initiative is an ongoing effort – new data contributions are welcome!
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , notRev
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  • 3
    Publication Date: 2023-07-13
    Description: Soft sediment permafrost coasts are well known for their very dynamic nature. In some places their erosion can reach tens of meters, even though the erosion time is restricted to the short open water season of three to four months per year. Due to its high ground ice content, the Yukon coast in the western Canadian Arctic is particularly prone to erosion. Building on results from Irrgang et al., 2018, we continued analyzing shoreline movements along the Yukon Coast using Pleiades satellite imagery covering the whole Yukon Coast from 2018 and 2022, as well as very highly resolved data from UAV overflights covering long term monitoring sites in 2019 and 2022. Using the Digital Shoreline Analysis System (DSAS) Esri ArcMap extension tool, we quantified shoreline movements for the time periods 2011-2018, and 2018-2022 for the entire coastline and for 2015-2019 and 2019- 2022 for long term monitoring sites. We used the same transects and shoreline proxies as in Irrgang et al., 2018, to ensure comparability of our results and elongate our observation series. We will show how recent shoreline position changes differ from past ones and will provide possible reasoning for these detected changes. We are using our multi-time-step shoreline change rate dataset of the Yukon Coast for training and validation purposes within the Earth Observation for Permafrost Coasts (EO4PAC) project. The increasing usage of machine learning approaches for automated shoreline delineation and shoreline change rate retrieval opens up new pathways – especially if it comes to exploring large and remote areas. Such datasets which contain on site derived shoreline change rates and manually derived shorelines from (very) high resolution airborne and spaceborne data are crucial for training algorithms, validation of results and thus for the quality improvement of machine learning techniques.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Conference , NonPeerReviewed
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  • 4
  • 5
    Publication Date: 2020-12-01
    Print ISSN: 0022-1236
    Electronic ISSN: 1096-0783
    Topics: Mathematics
    Published by Elsevier
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  • 6
    Publication Date: 2020-10-14
    Description: The future security of Internet of Things is a key concern in the cyber-security field. One of the key issues is the ability to generate random numbers with strict power and area constrains. “True Random Number Generators” have been presented as a potential solution to this problem but improvements in output bit rate, power consumption, and design complexity must be made. In this work we present a novel and experimentally verified “True Random Number Generator” that uses exclusively conventional CMOS technology as well as offering key improvements over previous designs in complexity, output bitrate, and power consumption. It uses the inherent randomness of telegraph noise in the channel current of a single CMOS transistor as an entropy source. For the first time multi-level and abnormal telegraph noise can be utilised, which greatly reduces device selectivity and offers much greater bitrates. The design is verified using a breadboard and FPGA proof of concept circuit and passes all 15 of the NIST randomness tests without any need for post-processing of the generated bitstream. The design also shows resilience against machine learning attacks performed by the LSTM neural network.
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
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  • 7
    Publication Date: 2020-11-12
    Description: The extraction of water-soluble bioactive compounds using different green methods is an eco-friendly alternative for valorizing agricultural wastes such as rice straw (RS). In this study, aqueous extracts of RS (particles 〈 500 µm) were obtained using ultrasound (US), reflux heating (HT), stirring (ST) and a combination of US and ST (USST) or HT (USHT). The extraction kinetics was well fitted to a pseudo-second order model. As regards phenolic compound yield, the US method (342 mg gallic acid (GAE). 100 g−1 RS) was more effective than the ST treatment (256 mg GAE·100 g−1 RS), reaching an asymptotic value after 30 min of process. When combined with HT (USHT), the US pre-treatment led to the highest extraction of phenolic compounds from RS (486 mg GAE·100 g−1 RS) while the extract exhibited the greatest antioxidant activity. Furthermore, the USHT extract reduced the initial counts of Listeria innocua by 1.7 logarithmic cycles. Therefore, the thermal aqueous extraction of RS applying the 30 min US pre-treatment, represents a green and efficient approach to obtain bioactive extracts for food applications.
    Electronic ISSN: 2304-8158
    Topics: Chemistry and Pharmacology
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  • 8
    Publication Date: 2021-02-03
    Description: Understanding the biological mechanisms of climatic adaptation is of paramount importance for the optimization of breeding programs and conservation of genetic resources. The aim of this study was to investigate genetic diversity and unravel genomic regions potentially under selection for heat and/or cold tolerance in thirty-two worldwide cattle breeds, with a focus on Chinese local cattle breeds adapted to divergent climatic conditions, Datong yak (Bos grunniens; YAK), and Bali (Bos javanicus) based on dense SNP data. In general, moderate genetic diversity levels were observed in most cattle populations. The proportion of polymorphic SNP ranged from 0.197 (YAK) to 0.992 (Mongolian cattle). Observed and expected heterozygosity ranged from 0.023 (YAK) to 0.366 (Sanhe cattle; SH), and from 0.021 (YAK) to 0.358 (SH), respectively. The overall average inbreeding (±SD) was: 0.118 ± 0.028, 0.228 ± 0.059, 0.194 ± 0.041, and 0.021 ± 0.004 based on the observed versus expected number of homozygous genotypes, excess of homozygosity, correlation between uniting gametes, and runs of homozygosity (ROH), respectively. Signatures of selection based on multiple scenarios and methods (FST, HapFLK, and ROH) revealed important genomic regions and candidate genes. The candidate genes identified are related to various biological processes and pathways such as heat-shock proteins, oxygen transport, anatomical traits, mitochondrial DNA maintenance, metabolic activity, feed intake, carcass conformation, fertility, and reproduction. This highlights the large number of biological processes involved in thermal tolerance and thus, the polygenic nature of climatic resilience. A comprehensive description of genetic diversity measures in Chinese cattle and YAK was carried out and compared to 24 worldwide cattle breeds to avoid potential biases. Numerous genomic regions under positive selection were detected using three signature of selection methods and candidate genes potentially under positive selection were identified. Enriched function analyses pinpointed important biological pathways, molecular function and cellular components, which contribute to a better understanding of the biological mechanisms underlying thermal tolerance in cattle. Based on the large number of genomic regions identified, thermal tolerance has a complex polygenic inheritance nature, which was expected considering the various mechanisms involved in thermal stress response.
    Electronic ISSN: 1664-8021
    Topics: Biology , Medicine
    Published by Frontiers Media
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  • 9
    Publication Date: 2021-03-19
    Description: Objective To present the clinical and radiological characteristics of women with severe structural deterioration of the bladder and upper urinary tract secondary to Primary Bladder Neck Obstruction (PBNO), and their outcomes after bladder neck incision (BNI). Methods Retrospective evaluation of adult women who underwent BNI for PBNO at one institution. Patients were assessed for symptoms, renal function, structural abnormalities of the urinary tract and video-urodynamics. PBNO diagnosis was confirmed with video-urodynamics in all patients. BNI was performed at the 4–5 and/or 7–8 o’clock positions. Postoperative symptoms, PVR, uroflowmetry and renal function were evaluated and compared to baseline. Results Median patient age was 56.5 years (range 40–80). All presented with urinary retention–four were on clean intermittent Catheterization (CIC) and two with a Foley catheter. All patients had bladder wall thickening and diverticula. Four women had elevated creatinine levels, bilateral hydronephrosis was present in five (83.3%). After BNI, all patients resumed spontaneous voiding without the need for CIC. Median Qmax significantly improved from 2.0 [1.0–4.0] mL/s to 15 [10–22.7] mL/s (p = 0.031). Median PVR decreased from 150 to 46 [22–76] mL (p = 0.031). There were no postoperative complications. Creatinine levels returned to normal in 3/4 (75%) patients. Conclusion PBNO in women may result in severe damage to the bladder and upper urinary tract. Despite severe structural abnormalities of the bladder, BNI was effective in reducing symptoms and improving structural and functional abnormalities of the lower and upper urinary tract.
    Electronic ISSN: 1932-6203
    Topics: Medicine , Natural Sciences in General
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  • 10
    Publication Date: 2020-10-31
    Description: Thermokarst lakes result from the thawing of ice-rich permafrost and are widespread across northern landscapes. These waters are strong emitters of methane, especially in permafrost peatland regions, where they are stained black by high concentrations of dissolved organic matter (DOM). In the present study, we aimed to structurally characterize the DOM from a set of peatland thermokarst lakes that are known to be intense sites of microbial decomposition and methane emission. Samples were collected at different depths from three thermokarst lakes in the Sasapimakwananisikw (SAS) River valley near the eastern Hudson Bay community of Kuujjuarapik–Whapmagoostui (Nunavik, Canada). Samples were analyzed by spectrofluorometry, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and elemental analysis. Fluorescence analyses indicated considerable amounts of autochthonous DOM in the surface waters of one of SAS 1A, indicating a strong bioavailability of labile DOM, and consequently a greater methanogenic potential. The three lakes differed in their chemical composition and diversity, suggesting various DOM transformations phenomena. The usefulness of complementary analytical approaches to characterize the complex mixture of DOM in permafrost peatland waters cannot be overlooked, representing a first step towards greater comprehension of the organic geochemical properties of these permafrost-derived systems.
    Electronic ISSN: 2073-4441
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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