Relief of Svalbard is an effect of varied morphogenetic, exogenic and endogenic processes. Tectonic and glacioisostatic movements of the Earth crust have occurred many a time in this region. Glacial, marine and periglacial features are particularly common. During the Late Quaternary the western Nordenskiöld Land underwent several sea transgressions, followed by glacier advances. Basing on erratics of crystalline rocks transported by sea ice, past sea levels have been established up to 250 m a.s.l. Marine terraces above 60 m a.s.l. date back to the Late Pleistocene, the lower ones are of the Holocene age.
Penguins (Aves: Sphenisciformes) hold much interest for many people, including (but not limited to) scientists. According to results of molecular studies, penguin history began in the Cretaceous, but the oldest bones assigned to these birds are Paleocene in age. The first fossil representative of Sphenisciformes formally described was Palaeeudyptes antarcticus, and this event took place 150 years ago. Since that time, several dozens of species have been erected, though not all of them have stood a test of time. The 21st century entered new dynamics into the paleontology of penguins, and (importantly) it concerned both the new material, and new theories. This paper summarizes what we currently know about extinct penguins and indirectly suggests the most promising areas for further research.
Penguin bones from the La Meseta Formation (Seymour Island, Antarctic Peninsula) are the only record of Eocene Antarctic Sphenisciformes. Being an abundant component of the youngest unit of the formation (Telm7), they are not so common in earlier strata. Here, I present the oldest penguin remains from the La Meseta Formation (Telm1-Telm2), often bearing close resemblance to their counterparts from younger units. Addressing the recent findings in fossil penguin systematics, I suggest there is too weak a basis for erecting new Eocene Antarctic taxa based on non-tarsometatarsal elements of penguin skeletons, and considering Oligocene species part of the studied assemblage. Finally, I conclude if the common ancestor of extant Sphenisciformes lived in the Eocene Antarctic (as suggested recently), penguins referred to Delphinornis seem to be prime candidates to that position.
The thermal state of permafrost is a crucial indicator of environmental changes occurring in the Arctic. The monitoring of ground temperatures in Svalbard has been carried out in instrumented boreholes, although only few are deeper than 10 m and none are located in southern part of Spitsbergen. Only one of them, Janssonhaugen, located in central part of the island, provides the ground temperature data down to 100 m. Recent studies have proved that significant warming of the ground surface temperatures, observed especially in the last three decades, can be detected not only just few meters below the surface, but reaches much deeper layers. The aim of this paper is evaluation of the permafrost state in the vicinity of the Polish Polar Station in Hornsund using the numerical heat transfer model CryoGrid 2. The model is calibrated with ground temperature data collected from a 2 m deep borehole established in 2013 and then validated with data from the period 1990-2014 from five depths up to 1 m, measured routinely at the Hornsund meteorological station. The study estimates modelled ground thermal profile down to 100 m in depth and presents the evolution of the ground thermal regime in the last 25 years. The simulated subsurface temperature trumpet shows that multiannual variability in that period can reach 25 m in depth. The changes of the ground thermal regime correspond to an increasing trend of air temperatures observed in Hornsund and general warming across Svalbard.
A significant limit to current understanding of cold coast evolution is the paucity of field observations regarding development of rocky coastlines and, in particular, lack of precise recognition of mechanisms controlling rock coast geomorphology in polar climates. Results are presented from a pilot survey of rock resistance using Schmidt Hammer Rock Tests (SHRT) across the recently deglacierized Nordenskioldbreen forefield and coastal zone, in central Spitsbergen, Svalbard. The aim is to improve understanding of the effects of rock weathering on high latitude coasts. SHRT across a field of roches moutonnées of metamorphic rocks, uncovered from ice over the last century and exposed to the operation of littoral processes, demonstrated significant relationships between rock surface resistance and distance from present shoreline, distance from the ice cliff as well as thickness of the snow cover. Sites closest to the present−day shoreline were characterized by lower resistance in comparison with more inland locations. The result support models that advocate intensification of weathering processes in cold region coastal settings.
The analysis of climate changes in of the Tarfala valley and Kebnekaise Mts area, and changes within the range of the Scandinavian Glaciation shows that even in the warmest period of Holocene there were favourable environmental conditions for permafrost of the Pleistocene origin to be preserved in this area. The results of electrical resistivity surveys together with analysis of available publications indicate that two layers of permafrost can be distinguished in the Storglaciären forefield. The shallower, discountinuous, with thickness ca. 2–6 meters is connected to the current climate, The second, deeper located layer of permafrost, separated with talik, is older. Its thickness can reach dozens of metres and is probably the result of permafrost formation during Pleistocene. The occurrence of two-layered permafrost in the Tarfala valley in Kebnekaise area shows the evolution of mountain permafrost may be seen as analogous to that in Western Siberia. This means that the effect of climate changes gives a similar effect in permafrost formation and evolution in both altitudinal and latitudinal extent. The occurrence of two-layered permafrost in Scandes and Western Siberia plain indicates possible analogy in climatic evolution, and gives opportunity to understand them in uniform way.
A data warehouse (DW) is a large centralized database that stores data integrated from multiple, usually heterogeneous external data sources (EDSs). DW content is processed by so called On-Line Analytical Processing applications, that analyze business trends, discover anomalies and hidden dependencies between data. These applications are part of decision support systems. EDSs constantly change their content and often change their structures. These changes have to be propagated into a DW, causing its evolution. The propagation of content changes is implemented by means of materialized views. Whereas the propagation of structural changes is mainly based on temporal extensions and schema evolution, that limits the application of these techniques. Our approach to handling the evolution of a DW is based on schema and data versioning. This mechanism is the core of, so called, a multiversion data warehouse. A multiversion DW is composed of the set of its versions. A single DWversion is in turn composed of a schema version and the set of data described by this schema version. Every DW version stores a DW state which is valid within a certain time period. In this paper we present: (1) a formal model of a multiversion data warehouse, (2) the set of operators with their formal semantics that support a DW evolution, (3) the impact analysis of the operators on DW data and user analytical queries. The presented formal model was a basis for implementing a multiversion DW prototype system.
In this article the author follows progressive evolution in web design that has been observed in Google Maps over the last 13 years (2005–2018). The analysis includes the graphic presentation of buttons, their layout and the changes in the functionality of the website. The results of the analysis corroborate the argument that it is possible to adapt the existing concept of progressive evolution, to the needs of Internet cartography. In the process of the analysis several crucial changes were spotted, such as the fact that as a result of the technological advancement the need to scroll the map with up, down, left and down buttons disappeared, being supplanted by the dragging function. In article all the discussed changes in Google Maps as an application for desktop computers and laptops, as well as a mobile application, prove that the product has been constantly improved. In the author’s opinion, the crucial aspect is to enrich the web map in the non-invasive way to make it as user-friendly and easy to use as possible. The synthetic juxtaposition allowed one to highlight the evolution, considered by the author an important feature of the non-invasive way of introducing changes. The author notes that progressive evolution on Google Maps and other internet maps will continue. It is important that the user’s needs are noticed during these changes.
Selected results of investigations concerning a shallow water part of the coastal zone, covering the surf zone and the swash zone, are presented. The above research has been carried out by means of field measurements, as well as data-driven and theoretical modelling. The investigations have led to development of a mathematical model of wave transformation and run-up on the shore in the Lagrangian system, as well as identification of infragravity waves (edge waves) in the multi-bar morphological beach system and their linkage with rhythmic shoreline forms (cusps). Some empirical relationships have been obtained for the description of number of bars in a bar system and dissipation of wave energy over such morphological structure. The experimental findings are based on field studies carried out at the IBW PAN Coastal Research Station (CRS) in Lubiatowo.
There has been considerable research done on multi-chamber mufflers used in the elimination of industrial venting noise. However, most research has been restricted to lower frequencies using the plane wave theory. This has led to underestimating acoustical performances at higher frequencies. Additionally, because of the space-constrained problem in most plants, the need for optimization of a compact muffler seems obvious. Therefore, a muffler composed of multiple rectangular fin-shaped chambers is proposed. Based on the eigenfunction theory, a four-pole matrix used to evaluate the acoustic performance of mufflers will be deduced. A numerical case for eliminating pure tones using a three-fin-chamber muffler will also be examined. To delineate the best acoustical performance of a space-constrained muffler, a numerical assessment using the Differential Evolution (DE) method is adopted. Before the DE operation for pure tone elimination can be carried out, the accuracy of the mathematical model must be checked using experimental data. The results reveal that the broadband noise has been efficiently reduced using the three-fin-chamber muffler. Consequently, a successful approach in eliminating a pure tone using optimally shaped three-fin-chamber mufflers and a differential evolution method within a constrained space has been demonstrated.
In sand moulds, at a distance of 3 mm from the metal- mould interface, the sensors of temperature, and of oxygen and hydrogen content were installed. Temperature and the evolution of partial gas pressure have been analysed in moulds bonded with bentonite with or without the addition of seacoal, water glass or furan resin. Moulds were poured with ductile iron. For comparison, also tests with the grey iron have been executed. It was found that the gas atmosphere near the interface depends mainly on the content of a carbonaceous substance in the mould. In the green sand moulds with 5% of seacoal or bonded with furan resin, after the mould filling, a sudden increase in the hydrogen content and the drop of oxygen is observed. This gas evolution results from the oxidation of carbon and reduction of water vapour in the mould material, and also from the reduction of water vapour and alloy reoxidation. In carbon-free sand, the evolution in the gas composition is slower because water vapour is reduced only at the interface. Changes of oxygen and hydrogen content in the controlled zone are determined by the transport phenomena.
In the present work, a constitutive model of materials undergoing the plastic strain induced phase transformation and damage evolution has been developed. The model is based on the linearized transformation kinetics. Moreover, isotropic damage evolution is considered. The constitutive model has been implemented in the finite element software Abaqus/Explicit by means of the external user subroutine VUMAT. A uniaxial tension test was simulated in Abaqus/Explicit to compare experimental and numerical results. Expansion bellows was also modelled and computed as a real structural element, commonly used at cryogenic conditions.
The article discusses the book Zmiana perspektywy. Gawęda nie tylko językoznawcza [Change of perspective. More than a tale of linguistics] by Zuzanna Topolińska (Cracow 2015). The author of this text emphasizes that the word gawęda [tale] in the book’s subtitle is misleading, given that, despite the style of language used in the book, Topolińska discusses important issues of a linguistic and intercultural nature. In her short essays in the fi rst part of the book Topolińska addresses the organizational structure of philology studies in Poland and Macedonia, she confronts the Polish and Macedonian approach to the dialectgeneral language relationship, she talks about language standards, about the differences between politeness in Poland and Macedonia, as well as the attitude towards women and the outlook toward religion in both countries. In the second part of the book Topolińska takes up lexical issues, giving examples of how under the infl uence of spiritual culture certain words in Polish and Macedonian that derive from the same core have taken on a different meaning. The author of the article concludes that this short and very personal book by Topolińska fulfi lls its task and subsequently alters his view on the linguistic and non-linguistic world of the Slavs.
Human brain is “the perfect guessing machine” (James V. Stone (2012) Vision and Brain, Cambridge, Mass: The MIT Press, p. 155), trying to interpret sensory data in the light of previous biases or beliefs. Bayesian inference is carried out by three complex networks of the human brain: salience network, central executive network, and default mode network. Their function is analysed both in neurotypical person and Attention Deficit Disorder. Modern human being having predictive brain and overloaded mind must develop social identity, whose evolution went probably through three stages: social selection based on punishment, sexual selection based on reputation, and group selection based on identity.
Dynamic Mine disasters can be induced by the instability and failure of a composite structure of rock and coal layers during coal mining. Coal seam contains many native defects, severely affecting the instability and failure of the compound structure. In this study, the effects of coal persistent joint on the strength and failure characteristics of coal-rock composite samples were evaluated using PFC2D software. The results show that with the increase of included angle α between the loading direction and joint plane direction, the uniaxial compressive stress (UCS) and peak strain of composite samples first decrease and then gradually increase. The elastic moduli of composite samples do not change obviously with α. The peak strain at α of 45° is the lowest, and the UCS at α of 30° is the smallest. This is inconsistent with theoretical analysis of lowest UCS at α of 45°. This is because that the local stress concentration caused by the motion inconformity of composite samples may increase the average axial stress of upper wall in PFC2D software. Moreover, the coal persistent joint promotes the transformation from the unstable crack expansion to the macro-instability of composite samples, especially at α of 30° and 45°. The majority of failures for composite samples occur within the coal, and no obvious damage is observed in rock. Their failure modes are shear failure crossing or along the coal persistent joint. The failure of composite sample at α of 30° is a mixed failure, including the shear failure along the persistent joint in coal and tensile failure of rock induced by the propagation of coal persistent joint.
In the paper an application of differential evolution algorithm to design digital filters with non-standard amplitude characteristics is presented. Three filters with characteristics: linearly growing, linearly falling, and non-linearly growing are designed with the use of the proposed method. The digital filters obtained using this method are stable, and their amplitude characteristics fulfill all design assumptions.
The new investigation method of the kinetics of the gas emission from moulding sands used for moulds and cores is presented in this paper. The gas evolution rate is presented not only as a function of heating time but also as a function of instantaneous temperatures. In relation to the time and heating temperature the oxygen and hydrogen contents in evolving gases was also measured. This method was developed in the Laboratory of Foundry Moulds Technology, Faculty of Foundry Engineering, AGH. Gas amounts which are emitted from the moulding sand at the given temperature recalculated to the time unit (kinetics) are obtained in investigations. Results of investigations of moulding sand with furan resin are presented - as an example - in the paper.
The evolution of David Harvey’s scientific interests. David Harvey’s work is a significant example of evolution and differences in contemporary human geography. It is characterised especially by three features related to one another: a constant change in scientific and research interests, a tendency to bridge the divisions between geographical specialities and scientific disciplines and the inclination towards deep theoretical and methodological reflection. A temporal and problem analysis allows distinguishing two phases of his research interests. In the first, neopositivist one, Harvey discusses methodological aspects of geography, being part of the process of changes in the research pattern of the maternal discipline; in the second, as a confirmed Marxist and radical geographer, he critically analyses contemporary urbanisation and the ideas of postmodernism and neoliberalism. Along with the evolution of scientific and research interests, Harvey’s approach to the examined issues changes – from an inquisitive researcher, concerned with the state of a native scientific discipline, he becomes a critical observer and a reformer of the surrounding reality.