66 research outputs found

    Analysis of encryption schemes in modern ransomware

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    In the past few years, activity of ransomware increased. As new variants and families of ransomware are developed, security systems have to keep up. Well designed encryption system is at the heart of ransomware and even a small mistake in the algorithm can break it. This paper analyzes 10 ransomware samples from various families. The goal of the analysis is to describe encryption schemes used in current ransomware. This includes key generation and storage, symmetric and asymmetric ciphers and their chosen implementation

    Corrosion Enhancement of PM Processed Magnesium by Turning Native Oxide on Mg Powders into Carbonates

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    In addition to its use as a lightweight material, pure magnesium is a promising candidate for prospective bioimplants considering its excellent biocompatible properties. Regardless of what Mg application is used, the ultimate goal is to improve magnesium\u27s mechanical properties and degradation behaviour. Because of the high affinity for oxygen native oxide layer of gas-atomized powders is naturally formed in contact with the atmosphere. S/TEM investigation of the native oxide of the Mg powder particles revealed a nonhomogeneous nano-crystalline MgO layer. MgO is relatively soluble in water and does not provide sufficient corrosion protection. Among various surface treatment methods, conversion of the non-protective magnesium oxide to carbonate products is possible depending on the environmental conditions. This work used a simple experimental method using CO2 and water vapour to achieve surface carbonation of Mg powders. Two carbonated samples and pure magnesium were prepared by direct extrusion. The samples after carbonation retained good mechanical properties and the layer of carbonates had a significant impact on corrosion resistance. 1 day carbonation resulted in transformation of native oxide into amorphous layer and reduction of corrosion rate. Longer carbonation (10 days) revealed layer growth and transformation of native oxide to crystalline nesquehonite structure

    Full-scale magnetic, microstructural, and physical properties of bilayered CoSiB/FeSiB ribbons

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    The paper is devoted to the detailed analysis of microstructural and magnetic properties of the as-quenched bilayered Co72.5Si12.5B15/Fe77.5Si7.5B15 ribbons prepared by the planar flow casting (PFC) method with single crucible. The interface between both amorphous Co- and Fe-based layers is not uniform and its thickness ranges from 0.5 to 6 μm over the whole ribbon length. Dependences of mechanical characteristics on the ribbon thickness show increase in Young’s modulus from 140 to 170 GPa and decrease in microhardness from 18 to 13 GPa, when measured from the wheel (Co) to air (Fe) side. By fixing the coiled ribbon on the planar sample holder a uniaxial magnetic anisotropy with the out-of-plane and the in-plane easy axis is induced on the air and wheel side, respectively. Bulk magnetic properties confirm that perpendicular anisotropy observed on the air side becomes stronger as getting deeper under the surface and overlaps the in-plane anisotropy from the wheel side. This is in good agreement with Mössbauer measurements. Magnetic characteristics (surface hysteresis loops and domains, bulk hysteresis loops and thermomagnetic curves) of the bilayered samples were further compared with the single-layered CoSiB and FeSiB alloys.Web of Science58169268

    Web usage analysis of Pillar 3 disclosed information by deposit customers in turbulent times

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    Market discipline has been a scrutinized area since the last financial crisis in 2008. Regulators strengthened their role particularly through Pillar 3 in Basel III. However, there are still some aspects of market discipline that deserve special attention to avoid future failures. This study focuses on the analysis of the interest and behaviour of deposit stakeholders based on website data dedicated to disclosures of commercial bank in Slovakia during and after turbulent times (period 2009–2012). The data consists of log files, and web mining techniques were applied (the modelling of web user behaviour in dependence on time - based on the proposals of the authors). The results show that also in turbulent times, stakeholders’ interest in Pillar 3 disclosures is low (in line with (Munk, Pilkova, Benko, & Blažeková, 2017)) and the highest interest was identified for the Pricing List category. After turbulent times, Pillar 3 categories (Pillar 3 related information and Pillar 3 disclosures) have weak interest, with peaks at the beginning of the year, and the highest increase was in the Business Conditions category. The results suggest that the enhancement of interest of key stakeholders in disclosures inevitably requires changes to deliver sufficient disclosure data structures and to design a disclosure policy that fulfils regulatory expectations. © 2021 The AuthorsScientific Grant Agency of the Ministry of Education of the Slovak Republic (ME SR); Slovak Academy of Sciences (SAS) [VEGA-1/0776/18, VEGA-1/0821/21]Slovenská Akadémia Vied, SAV: VEGA-1/0776/18, VEGA-1/0821/2

    Progress and trends in pediatric hematopoietic cell transplantation in Central-East European countries

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    Hematopoietic cell transplantation (HCT) is widely used as a treatment for acquired and congenital disorders. In recent years, a significant increase in transplant activity around the world has been observed, especially in Eastern European countries. This article aimed to assess progress and trends in pediatric HCT in Central-Eastern European countries between 2013 and 2018. Transplant activity survey in 2013 and 2018 in nine Central-Eastern European countries (Czech Republic, Croatia, Hungary, Lithuania, Poland, Romania, Slovakia, Slovenia, and Ukraine) was performed. The highest transplant rates in total were found in the Czech Republic and Hungary. When calculated per 10 million of the pediatric population, a 25.9% increase in the number of allo-HCT was observed with the highest in Croatia, Romania, Lithuania, and Poland; and a 12.2% increase in the number of auto-HCT was observed with the highest in Slovenia, Slovakia, Romania, Poland, Ukraine, and Croatia. We have shown, over the years 2013 and 2018, in some countries of Central-Eastern Europe that there was a significant increase in transplant activity, especially in those with the lower rates. This increase was observed mainly in centers already existing in 2013, especially in the allo-HCT setting. The rise of activity was significantly less influenced by the creation of new transplant centers or the increase in the number of pediatric transplant beds. In conclusion, our analysis indicates that in the Czech Republic, Hungary, Lithuania, and Slovenia, the actual infrastructure and the number of HCTs cover the needs, whereas in other countries, especially in Romania and Ukraine, the number of HCT needs to be increased

    Forest leaf litter beetles of Taiwan: first DNA barcodes and first insight into the fauna

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    We report the publication of 953 DNA barcodes of forest leaf litter beetles from central Taiwan, in total representing 334 spe- cies of 36 beetle families. This is the first bulk of data from the Taiwanese Leaf Litter beetles project focused on uncovering the under-explored diversity of leaf litter beetles across Taiwan. Based on these data, we provide the first records of the following taxa for Taiwan: family Sphindidae (genus Aspidiphorus Ziegler, 1821); tribes Trichonychini, Ctenistini, and Bythinoplectini (all Staphylinidae: Pselaphinae); genera Gyrelon Hinton, 1942, Thyroderus Sharp, 1885, Cautomus Sharp, 1885 (all Cerylonidae), Dermatohomoeus Hlisnikovský, 1963 (Leiodidae), Paraploderus Herman, 1970 (Staphylinidae: Oxytelinae), Thinocharis Kraatz, 1859 (Staphylinidae: Paederinae), Cephennodes Reitter, 1884, Napoconnus Franz, 1957 (both Staphylinidae: Scydmaeninae), Bicava Belon, 1884 (Latridiidae), Otibazo Morimoto, 1961, Seleuca Pascoe, 1871 and Acallinus Morimoto, 1962 (all Curculioni- dae); species Oodes (Lachnocrepis) japonicus (Bates, 1873) (Carabidae: Licininae), Drusilla obliqua (Bernhauer, 1916) (Staphylin- idae: Aleocharinae) and Coccotrypes advena Blandford, 1894 (Curculionidae: Scolytinae). The records of Anapleus Horn, 1873 (Histeridae) and Batraxis Reitter, 1882 (Staphylinidae: Pselaphinae) have been confirmed. The male of Sivacrypticus taiwanicus Kaszab, 1964 (Archeocrypticidae) is described for the first time. Gyrelon jenpani Hu, Fikáček & Matsumoto, sp. nov. (Cerylon- idae) is described, illustrated, and compared with related species. DNA barcodes associated larvae of 42 species with adults, we are concisely illustrating some of these: Oodes japonicus, Perigona cf. nigriceps Dejean, 1831 (both Carabidae), Ptilodactyla sp. (Ptilodactylidae), Maltypus ryukyuanus Wittmer, 1970 (Cantharidae), Drusilla obliqua, Myrmecocephalus brevisulcus (Pace, 2008), Diochus sp., Mimopinophilus sp. (all Staphylinidae), Stelidota multiguttata Reitter, 1877, Lasiodites inaequalis (Grouvelle, 1914) (both Nitidulidae), Lagria scutellaris Pic, 1910, and Anaedus spinicornis Kaszab, 1973 (both Tenebrionidae). We also report the first cases of Rickettsia infections in Scydmaeninae and Pselaphinae. All data (sequences, metadata, and voucher photos) are made public in BOLD database and in a Zenodo Archive

    Microstructural study of the crystallization of amorphous Fe-Sn-B ribbons

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    Amorphous Fe78Sn5B17 ribbons were prepared by planar flow casting. The thermodynamic stability and the kinetics of observed phase transformations were monitored by thermal analysis. The structure and morphology of phases forming upon the thermally activated crystallization is studied by X-ray diffraction and transmission electron microscopy. The crystallization begins by nucleation-and-growth of specific nanocrystalline bcc-Fe(Sn) phase, its structure is explored more in details and the role of Sn in its formation is discussed. In the next step of the crystallization a transformation of remaining amorphous matrix to iron borides runs via rather complex process, which is inspected more in details as well.Web of Science61546646

    On the Coevolution of Transposable Elements and Plant Genomes

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    Plant genomes are unique in an intriguing feature: the range of their size variation is unprecedented among living organisms. Although polyploidization contributes to this variability, transposable elements (TEs) seem to play the pivotal role. TEs, often considered intragenomic parasites, not only affect the genome size of the host, but also interact with other genes, disrupting and creating new functions and regulatory networks. Coevolution of plant genomes and TEs has led to tight regulation of TE activity, and growing evidence suggests their relationship became mutualistic. Although the expansions of TEs represent certain costs for the host genomes, they may also bring profits for populations, helping to overcome challenging environmental (biotic/abiotic stress) or genomic (hybridization and allopolyploidization) conditions. In this paper, we discuss the possibility that the possession of inducible TEs may provide a selective advantage for various plant populations

    NATO Advanced Research Workshop on Properties and Applications of Nanocrystalline Alloys from Amorphous Precursors

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    Metallic (magnetic and non-magnetic) nanocrystalline materials have been known for over ten years but only recent developments in the research into those complex alloys and their metastable amorphous precursors have created a need to summarize the most important accomplishments in the field. This book is a collection of articles on various aspects of metallic nanocrystalline materials, and an attempt to address this above need. The main focus of the papers is put on the new issues that emerge in the studies of nanocrystalline materials, and, in particular, on (i) new compositions of the alloys, (ii) properties of conventional nanocrystalline materials, (iii) modeling and simulations, (iv) preparation methods, (v) experimental techniques of measurements, and (vi) different modern applications. Interesting phenomena of the physics of nanocrystalline materials are a consequence of the effects induced by the nanocrystalline structure. They include interface physics, the influence of the grain boundaries, the averaging of magnetic anisotropy by exchange interactions, the decrease in exchange length, and the existence of a minimum two-phase structure at the atomic scale. Attention is also paid to the special character of the local atomic ordering and to the corresponding interatomic bonding as well as to anomalies and particularities of electron density distributions, and to the formation of metastable, nanocrystalline (or quasi-crystalline) phases built from exceptionally small grains with special properties. Another important focus of attention are new classes of materials which are not based on new compositions, but rather on the original and special crystalline structure in the nanoscale
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