Search Results (9)

The increasing use of the Internet of Things (IoT) in homes and industry brings significant security and privacy challenges, while also considering trade-off for performance, energy consumption, and processing capabilities. Few explicit and specific guidelines exist to help architects in considering these trade-offs while designing secure IoT systems. This article proposes to address this situation by extending the well-known architectural tactics taxonomies with IoT-specific trade-offs; to preserving auditability, the trade-offs address the quality characteristics of the ISO 25010:2023 standard. The proposed technique and catalog are illustrated with the design of the Nunatak environmental monitoring system. The proposal was empirically validated with a controlled experiment, where a balanced mix of 12 novice and expert practitioners had to design a secure IoT Environmental Monitoring System; they used similar architectural tactics catalogs, with versus without trade-off information. Results suggest that having this information yield significant improvements in decision-making effectiveness (Precision) and usefulness (F1-Score), particularly benefiting less experienced designers. Wider adoption of trade-off-aware catalogs of architectural tactics will allow systematic, auditable design of secure IoT systems, and especially so by novice architects. Full article

On the basis of data collected since 1961, the authors of the current article conducted an analysis of the distribution of Uropodina (Acari: Mesostigmata) species in Poland. The areas of occurrence of the species were compared with the range boundaries of the successive Pleistocene glaciations in Poland. The second aim of the study was to establish the importance of the former nunataks (paleonunataks) for the preservation of biodiversity of this group of mites in Poland. The study has revealed that there are six types of distribution of Uropodina species in the area of Poland: (i) species distributed consistently in the whole area of the country, (ii) species having their northern range of occurrence in Poland, (iii) species having their north-western range of occurrence, (iv) species having their north-eastern range of occurrence, (v) species of boreal-mountainous distribution with evident disjunction in central Poland, and (vi) Carpathian species migrating northwards along the Vistula River. The analyses of the species composition of Uropodina communities on nunataks shows that the concave nunatak in Jura Krakowsko-Czestochowska, described in the literature as the “Jurassic Inland Oasis”, turned out to be the location with the highest Uropodina diversity, whereas on the nunatak of the Ślęża Massif, which was covered by two glaciations, the Uropodina diversity was the lowest. Full article

The Southern Patagonian Icefield (SPI) is the largest continuous ice mass in the Southern Hemisphere outside Antarctica. It has been shrinking since the Little Ice Age (LIA) period, with increasing rates in recent years. An uplift of crustal deformation in response to this deglaciation process has been expected. The goal of this investigation is to analyze the crustal deformation caused by ice retreat using time-series data from continuous GPS stations (2015–2020) in the northern area of the SPI. For this purpose, we installed two continuous GPS stations on rocky nunataks of the SPI (the GRCS near Greve glacier and the GBCS close by Cerro Gorra Blanca). In addition, ice elevation changes (2000–2019) were analyzed by the co-registration of the SRTM digital elevation model and ICESat elevation data points. The results of the vertical components are positive (36.55 ± 2.58 mm a⁻¹), with a maximum at GBCS, indicating the highest rate of crustal uplift ever continuously recorded in Patagonia; in addition, the mean horizontal velocities reached 11.7 mm a⁻¹ with an azimuth of 43°. The negative ice elevation changes detected in the region have also accelerated in the recent two decades, with a median $\Delta h$ (elevation change) of −3.36 ± 0.01 m a⁻¹ in the ablation zone. The seasonality of the GPS signals was contrasted with the water levels of the main Patagonian lakes around the SPI, detecting a complex interplay between them. Hence, the study sheds light on the knowledge of the crustal uplift as evidence of the wastage experienced by the SPI glaciers. Full article

Cosmogenic nuclides are widely used to constrain the landscape history of glaciated areas. At nunataks in continental polar regions with extremely arid conditions, cosmogenic nuclides are often the only method available to date the ice thinning history of the glacier. However, the amount of cosmogenic isotopes accumulated at the surface of nunataks depends not only on the length of time that rock has been exposed since the last deglaciation but also on the full history of the surface, including muon production under ice, exposure during previous interglacials, subaerial weathering rate, glacial erosion rate, and uplift rate of the nunatak. The NUNAtak Ice Thinning model (NUNAIT) simulates the cosmonuclide accumulation on vertical profiles, fitting the aforementioned parameters to a set of multi-isotope apparent ages from samples taken at different elevations over the ice-sheet surface. The NUNAIT calculator is an easy-to-use tool that constrains parameters that describe the geological history of a nunatak from a set of surface exposure ages. Full article

The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps. Full article

We investigated the microstructures of five ice core samples from the Styx Glacier, northern Victoria Land, Antarctica. Evidence of dynamic recrystallization was found in all samples: those at 50 m mainly by polygonization, and those at 170 m, largely by grain boundary migration. Crystallographic preferred orientations of all analyzed samples (view from the surface) typically showed a single cluster of c-axes normal to the surface. A girdle intersecting the single cluster occurs at 140–170 m with a tight cluster of a-axes normal to the girdle. We interpret the change of crystallographic preferred orientations (CPOs) at <140 m as relating to a combination of vertical compression, and shear on a horizontal plane, and the girdle CPOs at depths >140 m, as the result of horizontal extension. Based on the data obtained from the ground penetrating radar, the underlying bedrock topography of a nunatak could have generated the extensional stress regime in the study area. The results imply changeable stress regimes that may occur during burial as a result of external kinematic controls, such as an appearance of a small peak in the bedrock. Full article

The endolithic niche represents an ultimate refuge to microorganisms in the Mars-like environment of the Antarctic desert. In an era of rapid global change and desertification, the interest in these border ecosystems is increasing due to speculation on how they maintain balance and functionality at the dry limits of life. To assure a reliable estimation of microbial diversity, proper sampling must be planned in order to avoid the necessity of re-sampling as reaching these remote locations is risky and requires tremendous logistical and economical efforts. In this study, we seek to determine the minimum number of samples for uncovering comprehensive bacterial and fungal diversity, comparing communities in strict vicinity to each other. We selected three different locations of the Victoria Land (Continental Antarctica) at different altitudes and showing sandstone outcrops of a diverse nature and origin—Battleship promontory (834 m above sea level (a.s.l.), Southern VL), Trio Nunatak (1,470 m a.s.l., Northern VL) and Mt New Zealand (3,100 m a.s.l., Northern VL). Overall, we found that a wider sampling would be required to capture the whole amplitude of microbial diversity, particularly in Northern VL. We concluded that the inhomogeneity of the rock matrix and the stronger environmental pressure at higher altitudes may force the communities to a higher local diversification. Full article

Spitsbergen has recently experienced a continuous deglaciation process, linked to both glacier front retreat and lowering of the glacier surface. This process is accompanied by permafrost aggradation from the top of the slopes down to the glacier. Here, the authors determine the rate of permafrost expansion in this type of vertical profile. To this end, seven nunataks across the island were analysed using Landsat satellite imagery, a high-resolution digital elevation model (ArcticDEM), and geoinformation software. Over the last 24–31 years, new nunataks gradually emerged from the ice cover at an average linear rate of 0.06 m a⁻¹ per degree of increment of the slope of the terrain at an average altitude of approximately 640 m a.s.l. The analysis showed that the maximum rate of permafrost expansion down the slope was positively correlated with the average nunatak elevation, reaching a value of approximately 10,000 m² a⁻¹. In cold climates, with a mean annual air temperature (MAAT) below 0 °C, newly exposed land is occupied by active periglacial environments, causing permafrost aggradation. Therefore, both glacial and periglacial environments are changing over time concomitantly, with permafrost aggradation occurring along and around the glacier, wherever the MAAT is negative. Full article

The Vestgӧtabreen Complex exposed in the Southwestern Caledonian Basement Province of Svalbard comprises two Caledonian high-pressure units. In situ white mica ⁴⁰Ar/³⁹Ar and monazite Th-U-total Pb geochronology has resolved the timing of the tectonic evolution of the complex. Cooling of the Upper Unit during exhumation occurred at 476 ± 2 Ma, shortly after eclogite-facies metamorphism. The two units were juxtaposed at 454 ± 6 Ma. This was followed by subaerial exposure and deposition of Bullbreen Group sediments. A 430–400 Ma late Caledonian phase of thrusting associated with major sinistral shearing throughout Svalbard deformed both the complex and the overlying sediments. This phase of thrusting is prominently recorded in the Lower Unit, and is associated with a pervasive greenschist-facies metamorphic overprint of high-pressure lithologies. A c. 365–344 Ma geochronological record may represent an Ellesmerian tectonothermal overprint. Altogether, the geochronological evolution of the Vestgӧtabreen Complex, with previous petrological and structural studies, suggests that it may be a correlative to the high-pressure Tsäkkok Lens in the Scandinavian Caledonides. It is suggested that the Vestgӧtabreen Complex escaped to the periphery of the orogen along the sinistral strike-slip shear zones prior to, or during the initial stages of continental collision between Baltica and Laurentia. Full article