bluuebunny/crossref_metadata_2025_split huggingface dataset:
From the discrete to the continuous brachistochrone: a tale of two proofs
Authors: Agmon David , Yizhaq Hezi 
Published: August 2020

Abstract
In a previous paper (2019 Eur. J. Phys.
40 035005) we showed how to design a discrete brachistochrone with an arbitrary number of segments. We have proved, numerically and graphically, that in the limit of a large number of segments, N ≫ 1, the discrete brachistochrone converges into the continuous brachistochrone, i.e. into a cycloid. Here we show this convergence analytically, in two different ways, based upon the results we obtained from investigating the characteristics of the discrete brachistochrone. We prove that at any arbitrary point, the sliding bead has the same velocity on both the continuous and discrete paths, and the radius of the curvature of both paths is the same at corresponding points. The proofs are based on the well-known fact that the curve of a cycloid is generated by a point attached to the circumference of a rolling wheel. We also show that the total acceleration magnitude of the bead along the cycloid is constant and equal to g, whereas the acceleration vector is directed toward the center of the wheel, and it rotates with a constant angular velocity.
Induced-charge electrokinetics in microfluidics: a review on recent advancements
Authors: Manshadi Mohammad K D , Mohammadi Mehdi , Zarei Mohammad , Saadat Mahsa , Sanati-Nezhad Amir 
Published: August 2020

Abstract
Applying an external electric field over a polarizable electrode or object within microchannels can induce an electric double layer (EDL) around channel walls and create induced-charge electrokinetics (ICEK) within channels. The primary consequence of the induced charge is the generation of micro-vortices around the polarizable electrode or object, presenting great potential for various microfluidic applications. This review presents the advances in theoretical, numerical and experimental studies on the physics and applications of ICEK within microfluidics. In particular, the characteristics and performance of ICEK-based microfluidic components in active micromixers, micropumps, and microvalves are critically reviewed, followed by discussing the applications of ICEK in electrophoresis and particle/cell manipulation within microfluidics. Furthermore, the opportunities and challenges of ICEK-based microfluidic devices are highlighted. This work facilitates recognizing deliverable ICEK-based microfluidic technologies with unprecedented functionality for the next generation of biomedical applications with predictable manufacturability and functionality.
Two-dimensional ultrathin van der Waals heterostructures of indium selenide and boron monophosphide for superfast nanoelectronics, excitonic solar cells, and digital data storage devices
Authors: Mohanta Manish Kumar , Kishore Amal , De Sarkar Abir 
Published: August 2020

Abstract
Semiconducting indium selenide (InSe) monolayers have drawn a great deal of attention among all the chalcogenide two-dimensional materials on account of their high electron mobility; however, they suffer from low hole mobility. This inherent limitation of an InSe monolayer can be overcome by stacking it on top of a boron phosphide (BP) monolayer, where the complementary properties of BP can bring additional benefits. The electronic, optical, and external perturbation-dependent electronic properties of InSe/BP hetero-bilayers have been systematically investigated within density functional theory in anticipation of its cutting-edge applications. The InSe/BP heterostructure has been found to be an indirect semiconductor with an intrinsic type-II band alignment where the conduction band minimum (CBM) and valence band maximum (VBM) are contributed by the InSe and BP monolayers, respectively. Thus, the charge carrier mobility in the heterostructure, which is mainly derived from the BP monolayer, reaches as high as 12 × 103 cm2 V−1 s−1, which is very much desired in superfast nanoelectronics. The suitable bandgap accompanied by a very low conduction band offset between the donor and acceptor along with robust charge carrier mobility, and the mechanical and dynamical stability of the heterostructure attests its high potential for applications in solar energy harvesting and nanoelectronics. The solar to electrical power conversion efficiency (20.6%) predicted in this work surpasses the efficiencies reported for InSe based heterostructures, thereby demonstrating its superiority in solar energy harvesting. Moreover, the heterostructure transits from the semiconducting state (the OFF state) to the metallic state (the ON state) by the application of a small electric field (∼0.15 V Å−1) which is brought about by the actual movement of the bands rather than via the nearly empty free electron gas (NFEG) feature. This thereby testifies to its potential for applications in digital data storage. Moreover, the heterostructure shows strong absorbance over a wide spectrum ranging from UV to the visible light of solar radiation, which will be of great utility in UV—visible light photodetectors.
Circularly polarized x-ray generation from an ionization induced laser plasma electron accelerator
Authors: Feng Jie , Li Yifei , Geng Xiaotao , Li Dazhang , Wang Jinguang , Mirzaie Mohammad , Chen Liming 
Published: August 2020

Abstract
A laser plasma accelerator could provide high-intensity x-ray radiation as the basis for the next generation compact radiation source. However, there is still a lack of tunability for the radiation polarization, especially the circular polarization. Here, we propose a new method for achieving intense circularly polarized x-rays via circularly polarized 20 TW laser pulses driving plasma wakefield acceleration in the regime of ionization injection. When the laser pulse duration is long enough, the ionization injected electrons would not only possess angular momentum, but also be resonant with the laser pulses, resulting in helix structure trajectories in the process of acceleration. In our simulation, we acquired synchrotron radiation with the circularly polarized degree Pc
∼ 0.8, the pulse duration ∼16 fs, the energy spectrum peak ∼1 keV and the brilliance ∼1.8 × 1020 photons s−1 mm−2 mrad−2/0.1%BW. Such an ultra-fast and ultra-brilliant circularly polarized x-ray source has excellent application prospects in the analysis of complex bio-macro-molecule structures and for probing warm dense matter.
Recent progress in multiple chiral doublet bands *
Authors: Wang Shou-Yu 
Published: August 2020

Abstract
Recent progress regarding multiple chiral doublet bands (

) is reviewed from the experimental and theoretical perspectives. In particular, the experimental findings, theoretical predictions, selection rule for electromagnetic transitions,

with octupole correlations, and some related topics are highlighted. Based on these discussions, it is of great scientific interest to search for the other

, as well as possible chiral wobblers, chirality-parity quartet bands, and chirality-pseudospin triplet (or quartet) bands in the nuclear system.
Stand age and climate influence forest ecosystem service delivery and multifunctionality
Authors: Jonsson Micael , Bengtsson Jan , Moen Jon , Gamfeldt Lars , Snäll Tord 
Published: August 2020

Abstract
We examine how levels of multiple ecosystem services (ESs) change with succession in forests with different tree species composition. More specifically we ask how ecosystem age interacts with environmental conditions to regulate ES delivery. Using the nationwide Swedish forest inventory, comprising boreal and temperate regions, we investigated how levels of six provisioning, regulating, recreational, and/or cultural forest ESs changed with forest age (10–185 years) in stands of different tree species composition. We also tested whether the number of ESs delivered (i.e. multifunctionality) changed substantially with stand age, using different threshold levels for ES delivery. Accounting for environmental conditions and stand properties, we found that levels of single ESs changed with stand age. Tree biomass production usually peaked in young to medium aged stands. In contrast, production of berries and game, and services related to biodiversity, were typically highest in old stands (120–185 years). Consistent with this strong temporal tradeoff, multifunctionality at lower threshold levels increased with stand age in most monocultures and mixtures, with the highest multifunctionality being reached somewhere between 100 and 185 years, depending on tree species composition. This was not evident for the highest threshold ES level (the top-20%), however. Moreover, multifunctionality usually decreased with warmer climatic conditions, with the exception of spruce–pine–birch mixtures. Taken together, our results show that a reduced forest age, e.g. due to forestry targeting early harvest of stands, most likely would limit the delivery of several ESs valued by society and result in less multifunctional forests. To maintain the capacity of forests to deliver high levels of multiple ESs, the role of stand age and tree species composition should be considered in decisions on how to manage future forests.
The arctic in the Russian socio-humanitarian discourse of the XXI century and political geography
Authors: Aladyshkin I V , Odinokaya M A , Rubtsova A V , Bocharov A A 
Published: August 2020

Abstract
The article analyzes the transformation of the Russian socio-humanitarian discourse of the Arctic in the last two decades in connection with the political course of the Russian Federation. The article considers the reasons and grounds for the demand for Arctic issues among Russian humanitarians, as well as changes in the image of the Russian North itself. Based on a combination of principles and methods of historiographical research and discourse analysis, the paper highlights key discursive strategies and categories, themes and subjects of scientific events and publications dedicated to the Arctic. The main problem points of the Arctic problem are highlighted and the dynamics of research priorities over the past two decades in the context of Russia’s political geography is traced. The author concludes that the Russian socio-humanitarian discourse considers the Arctic region based on a number of highly popular themes and motives that are set by the authorities and are key components of the narrative and symbolic complex of the Russian Arctic. It is argued that the observed growth of interest in the region is largely artificial, and the latest socio-humanitarian historiography of the Arctic is determined primarily by the official position of the state, which affects the overall level of research.
The study of the North of Russia by the scientific community of the late 19th – early 20th century
Authors: Brovina A A 
Published: August 2020

Abstract
The article presents the history of scientific research in the North of Russia. The scientific community regarded the European North of Russia as an important strategic and economically promising region. The researchers concerned about the problems of economic development of natural resources of the Northб have focused their attention on the European North of Russia since the 18th century. The article considers the period of the formation of scientific research and the early stage of development of scientific research in the North. It is shown that description and exploration of the territories rich in natural resources contributed to the development of both fundamental geological and geophysical research and the development of applied research trends that assisted the substantiation of the industrial prospects of the northern territories. However, the extremely unfavorable transport conditions of the northern territories interfered with the use of the identified natural resources. This territory had stayed poorly studied until the 20th century. It has been determined that the continuation of scientific research became one of the important aspects of public policy in the North. The results of scientific research were necessary both for the development of transport and for making strategic decisions, as well as for general economic growth and the study of the natural opportunities for the development of the northern economy. The activities of the scientific community became a determining factor in the subsequent industrial development of the northern territories.
Preservation of Unique Natural Territories of the North of Russia: from the History of the Creation of the Natural Heritage Site “The Virgin Forests of the Komi Republic”
Authors: Filippova T P 
Published: August 2020

Abstract
Based on a wide range of archival sources, the article considers the history of the creation of the UNESCO World Natural Heritage Site “The Virgin Forests of the Komi Republic” located in the Komi Republic on the western slopes of the Northern and Subpolar Urals. It includes the territories of two protected areas of the Pechora-Ilych Reserve and the National Park “Yugyd Va”, which make up the largest of the primary forests remaining in Europe. The level of the industrial development of the USSR and environmental transformation in the first half of the 20th century determined the wide involvement of academic knowledge in solving the problems of conservation of unique natural resources. The article considers the main directions and results of scientific work in the formulation and successful solution of the problems of nature conservation and the rational use of the resources of the northern region. Thanks to the scientists of the USSR Academy of Sciences more than two hundred objects were declared natural monuments on the territory of the Komi ASSR from the 1940s to the 1980s. The organization of the National Park “Yugyd Va” on the territory of the republic became one of the major scientific projects.
Greenland Environmental Laws at the Present Stage
Authors: Mokhorov D A , Voskresenskaya E V , Semenova K A , Kulik A S 
Published: August 2020

Abstract
The article considers the environmental legislation of Greenland as the autonomy of the Arctic state, its environmental policy and the main stages of its development. The authors describe the interaction of Greenland with Denmark and the European Union in the field of energy, water management, fishing, climate policy, and pollution control. The conclusion is drawn that, despite the fact that the environmental development of the autonomy started only at the end of the 20th century, significant improvements have already been made in the legal regulation of energy and water resources protection. The main areas of concern for Greenland are waste management and climate change. Despite the participation of Greenland in the Arctic and European Union programs and the development of its national policies to combat climate change, the level of greenhouse gas emissions from the rest of the world has a negative effect on the environmental situation in Greenland, thereby confirming the fears of researchers about the irreversibility of the Greenland glaciers melting and the general climate warming by more than 1.5 °C to the beginning of 2100. Nevertheless, despite large mineral deposits on its territory, the government of Greenland pursues the policy of sustainable environmental development.
Impact of regulatory features on waste management in the Nordic countries
Authors: Ivanova L V 
Published: August 2020

Abstract
The article discusses the problem of waste management relevant for the Russian Federation and the regions of its Arctic on the example of a number of Arctic states - the countries of Northern Europe. The existing waste management system, features of the relevant regulatory framework and competition development in this area are considered. The legislative framework of waste management in the Nordic countries is heavily influenced by European Union directives and international law. Regulatory documents lay the foundations of management and set goals for prevention of waste generation, reuse, recycling, etc. The Nordic countries have much in common, including cultural and legislative traditions. However, there are significant differences between them, ethat is one of the factors explaining the difference in the structure of waste management and the legislative framework in different countries of Northern Europe. Waste management issues have historically been the subject of discussion at the municipal level. Abolition or reduction of state regulation in a number of activities of the sector create opportunities for competition at the waste markets. In most cases, there is an obvious tendency to strengthen market orientation: many municipalities do not collect waste on their own, but use the services of state or private specialized enterprises. In most Nordic countries, existing laws and other regulations to some extent limit competition in waste management. It imposes obligations, but, at the same time, provides broad waste management rights. Within the current legislative framework, there are opportunities to increase competition in the field of waste management, for example, when the municipality decides to promote creation of a market through a tender. However, the existing regulatory framework may not be enough to improve the market structure or create new waste markets. In general, one can talk about development of competition in the field of waste management in the Nordic countries. Market relations create favorable conditions for making innovative decisions that will help reducing costs, decreasing lack of resources, and ensuring efficiency of the waste management sector as a whole. In addition, new solutions and some flexibility in a competitive environment can make a positive contribution to solving environmental problems.
Snow cover study in the zone of influence of the Severonickel plant
Authors: Slipenchuk M , Kirillov S , Vorobievskaya E , Sedova N 
Published: August 2020

Abstract
Abstract The article discusses the problems associated with the anthropogenic impact of the Severonickel plant on the environment in the Murmansk region of the Russian Federation. Due to the operation of this plant, sulfur compounds and metal-containing aerosols prevail in the structure of atmospheric emissions of the Murmansk region. In order to identify the main areas of impact of the Severonickel plant, snow samples were taken directly near the industrial site, as well as at points north and south of the plant, as well as in the city of Monchegorsk and its environs. The evaluation of the concentration of heavy metals was carried out in the ecological and analytical laboratory of the Department of Environmental Management and in the laboratory of atomic absorption of the Department of Landscape Geochemistry, Faculty of Geography, Moscow State University. The highest values of the index of total pollution with heavy metals of snow are observed at sampling points located 750-1000 m north of the industrial zone, as well as at the point located 2.5 km northeast of Monchegorsk, at the intersection of the Kola highway and the railway station highway. According to 2017, the reaction rim of influence of the enterprise can be traced much further south and north. If according to the data of 2019, the points with significant indices of total pollution are located 2.5–3 km to the north and south of the plant, then, according to 2017, the influence of production can be traced in the radius of 8–10 km. Most likely, this difference in indicators is due to the frequency of winds. In 2019, the transfer of pollutants was much less active.
Impact of climatic effects on the environment and the economy of the Russian Arctic
Authors: Sorokina T , Trofimova A , Kondratov N , Shumilova Yu 
Published: August 2020

Abstract
The Arctic is a high-latitude part of the Far North, including the land area and the marine environment of the Arctic Ocean within the exclusive economic zone of the Russian Federation. The importance of the Arctic issues are conditioned by the fact that in the Russian Federation shaping and scientific rationale of the priorities of circumpolar territory development are ones of the key objectives of Russian economic development and modernization. Russian Arctic development should be based on the principles of resource efficiency and precautionary principle. It should be founded on cutting-edge research and professional competencies of labour force, who are adapted to work in the Arctic, and should be accompanied by innovative technologies. Studying different directions and problems of the Arctic development shows a particularly crucial role of geography in framing and solving national economic purposes. The role of geography is becoming more important not only because of huge impact of the geographical factor in the Far North and the Arctic regions but also due to remarkable differentiation of natural and social conditions of economic activity. In recent decades, the Arctic is undergoing rapid transformations in the natural and socio-economic environment, which are developing against the background of a lack of knowledge about them. One example is climate change, which can have an impact on environmental management on a global scale.
Assessment of the state of the socio-economic sphere of the Arctic territories of the world’s countries
Authors: Krasulina O Y , Rossokhin V V , Khazov V K 
Published: August 2020

Abstract
The article gives an assessment of the Arctic as a special territory, and the main natural and geographical features are described. Special attention is paid to national and regional differences in population density and GDP, wages and unemployment in the Arctic countries. The authors assess the socio-economic sphere of eight countries: Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden, USA. The authors compared the dynamics of macroeconomic indicators of the Arctic regions and the country in which they are located. An analysis was carried out that identified countries and regions with consistently high social and demographic potential, as well as countries with similar climatic and socio-economic characteristics that effectively complement each other (Norway, Sweden and Finland). Among the Arctic countries, Norway is characterized by oil and gas complexes and fish resources, Finland is characterized by innovative technologies for processing bioresources and mining, Sweden by mining of ore minerals, and the woodworking industry. The article suggests further study of Arctic countries with consistently high socio-economic indicators in order to apply their experience to the development of the Arctic territory of Russia. In order to achieve this, it is necessary to activate technological partnership with the use of innovative digital technologies. The authors emphasize the development of international cooperation as the most progressive mechanism for the development of the world. World Practice is a good basis for developing a unified Concept of the North, because different Arctic countries have identical socio-economic and scientific problems.
Information and communication technologies as a component of the innovative potential of the Murmansk region
Authors: Naumova O , Milskaya E 
Published: August 2020

Abstract
The article describes a special resource of the innovative potential of the regions -information and communication technologies (resource ICT). The features of the ICT development are analyzed, their impact on the innovative potential of the industry in the Murmansk region. The level of development of information and communication technologies provides the necessary coordination of the actions of participants in economic activity. The characteristic of the most important industries of the Murmansk region is given. The main factors of innovative potential are characterized and the influence of ICT development on the innovative development of industry is determined.