4,815 research outputs found
Mineral resources and national economic security: current features
Purpose is to estimate current mineral and raw material complex and its effect on national economic security basing upon determination and analysis of the integrated index.
Methods. Eleven countries of the world with the developed iron-mining industry have been selected as the object of the research. Information database has been formed to calculate integrated index of mineral and raw material security (MRMS). Seven indicators characterizing economic and technical state of iron-ore industry have been specified as performance measures. The indicators have been classified according to their effect on final integrated estimation of MRMS state in a country. The study involves proprietary methodology to calculate integrated index of MRMS.
Findings. MRMS has been distinguished in the system of national security. Following indicators have been proposed to be included into the system of national MRMS performance measures: production of mineral resources per capita; resource intensity of the economy; resource-efficiency of the economy; provision with the required mineral
resources; export quota; intensity of mineral raw material consumption; and ratio of the volumes of raw material extraction and export of the products of primary processing and recycling (utilization efficiency). Positions and roles of mining industry in terms of provision with resources for the world economy have been evaluated on the basis of system approach (with the emphasis on mining industry). Basic current tendencies in the development of world
mining industry have been highlighted including the following ones: increase in the consumption of mineral ore resources; growing intensity of the consumption of mined crude ore deposits and, consequently, depletion of the most commercial deposits; prevailing of mineral carbohydrate raw materials in the world mining industry; and increase in ore reserves consumption by the developing countries. Scientific and methodological approach to estimate the effect of mining industry upon the level of economic security has been approbated; the results have made it possible to evaluate MRMS of 11 leading producers of iron-ore raw material.
Originality. It is in the use of innovative complex (integrated) estimation of MRMS level in certain countries which has allowed performing their grouping in term of corresponding security levels and determining the factors effecting economic performance of mineral and raw material component.
Practical implications. The proposed integrated approach to the estimation of MRMS level of the countries favours the substantiation of the strategy to strengthen economic security in terms of the mining industry influence.Мета. Оцінка сучасного стану мінерально-сировинного комплексу та його впливу на економічну безпеку країни на основі визначення й аналізу інтегрального показника.
Методика. Як об’єкт дослідження обрані 11 країн світу з розвиненою гірничодобувною залізорудною про-промисловістю. Сформована інформаційна база даних для розрахунку інтегрального показника мінерально-сировинної безпеки (МСБ). Як показники оцінки були обрані 7 індикаторів, що характеризують економічний і технічний стан підприємств залізорудної галузі. Індикатори були прокласифіковані відповідно до їх впливу на підсумкову інтегральну оцінку стану МСБ країни. У дослідженні використана авторська методика розрахунку інтегрального показника МСБ.
Результати. Виділена МСБ в системі національної безпеки країни й запропоновано включити в систему показників оцінки МСБ країни такі індикатори, як: виробництво мінеральних ресурсів на душу населення; ресурсоємність економіки; ресурсоефективність економіки; забезпеченість необхідними мінеральними ресурсами; експортна квота; інтенсивність використання мінеральної сировини; співвідношення обсягів видобутку сировини і обсягів експорту продукції первинної та вторинної переробки (ефективність використання). Оцінені місця і ролі добувної промисловості в ресурсному забезпеченні світового господарства на основі системного підходу (з акцентом на гірничодобувну промисловість). Виділені основні сучасні тенденції розвитку світової гірничодобувної промисловості, серед яких: зростання обсягів споживання мінеральних рудних ресурсів; підвищення інтенсивності використання покладів викопної рудної сировини і, відповідно, вичерпання найбільш продуктивних родовищ; перевага у світовій добувній промисловості мінеральної вуглеводневої сировини; збільшення обсягів споживання рудних ресурсів країнами, що розвиваються. Здійснено апробацію запропонованого науково-методичного підходу до оцінки впливу добувної галузі на рівень економічної безпеки, за результатами якого оцінена МСБ 11 провідних виробників залізорудної сировини.
Наукова новизна. Полягає у використанні нової комплексної (інтегральної) оцінки рівня МСБ країн, що дозволило провести їх групування за відповідними рівнями безпеки й визначити фактори впливу на стан економіки мінерально-сировинної компоненти.
Практична значимість. Запропонований інтегральний підхід до оцінки рівня МСБ країн сприяє науковому обґрунтуванню стратегії посилення економічної безпеки в контексті впливу добувної галузі.Цель. Оценка современного состояния минерально-сырьевого комплекса и его влияния на экономическую безопасность страны на основе определения и анализа интегрального показателя.
Методика. В качестве объекта исследования выбраны 11 стран мира с развитой горнодобывающей железорудной промышленностью. Сформирована информационная база данных для расчета интегрального показателя минерально-сырьевой безопасности (МСБ). В качестве показателей оценки были выбраны 7 индикаторов, характеризующих экономическое и техническое состояние предприятий железорудной отрасли. Индикаторы были проклассифицированы соответственно их влияния на итоговую интегральную оценку состояния МСБ страны. В исследовании использована авторская методика расчета интегрального показателя МСБ.
Результаты. Выделена МСБ в системе национальной безопасности страны и предложено включить в систему показателей оценки МСБ страны такие индикаторы, как: производство минеральных ресурсов на душу населения; ресурсоемкость экономики; ресурсоэффективность экономики; обеспеченность необходимыми минеральными ресурсами; экспортная квота; интенсивность использования минерального сырья; соотношение объемов добычи сырья и объемов экспорта продукции первичной и вторичной переработки (эффективность использования). Оценены места и роли добывающей промышленности в ресурсном обеспечении мирового хозяйства на основе системного подхода (с акцентом на горнодобывающую промышленность). Выделены основные современные тенденции развития мировой горнодобывающей промышленности, среди которых: рост объемов потребления минеральных рудных ресурсов; повышение интенсивности использования залежей ископаемой рудного сырья и, соответственно, исчерпания наиболее продуктивных месторождений; преобладание в мировой добывающей промышленности минерального углеводного сырья; увеличение объемов потребления рудных ресурсов развивающимися странами. Осуществлена апробация предложенного научно-методического подхода к оценке влияния добывающей отрасли на уровень экономической безопасности, по результатам которого оценена МСБ 11 ведущих производителей железорудного сырья.
Научная новизна. Заключается в использовании новой комплексной (интегральной) оценки уровня МСБ стран, что позволило провести их группировку по соответствующим уровням безопасности и определить факторы влияния на состояние экономики минерально-сырьевой компоненты.
Практическая значимость. Предложенный интегральный подход к оценке уровня МСБ стран способствует научному обоснованию стратегии усиления экономической безопасности в контексте влияния добывающей отрасли.The study carried out by the financial support of the “Russian Foundation for Basic Research” within the framework of the research project 18-410-230033 r a
Probing energy barriers and quantum confined states of buried semiconductor heterostructures with ballistic carrier injection: An experimental study
A three-terminal spectroscopy that probes both subsurface energy barriers and
interband optical transitions in a semiconductor heterostructure is
demonstrated. A metal-base transistor with a unipolar p-type semiconductor
collector embedding InAs/GaAs quantum dots (QDs) is studied. Using
minority/majority carrier injection, ballistic electron emission spectroscopy
and its related hot-carrier scattering spectroscopy measures barrier heights of
a buried AlxGa1-xAs layer in conduction band and valence band respectively, the
band gap of Al0.4Ga0.6As is therefore determined as 2.037 +/- 0.009 eV at 9 K.
Under forward collector bias, interband electroluminescence is induced by the
injection of minority carriers with sub-bandgap kinetic energies. Three
emission peaks from InAs QDs, InAs wetting layer, and GaAs are observed in
concert with minority carrier injection.Comment: 11 pages, 4 figures, submitted to Physical Review
Circulating T cell subsets are altered in individuals with chronic spinal cord injury
Traumatic spinal cord injury (SCI) induces changes in the immune system, both acutely and chronically. To better understand changes in the chronic phase of SCI, we performed a prospective, observational study in a research institute and Department of Physical Medicine and Rehabilitation of an academic medical center to examine immune system parameters, including peripheral immune cell populations, in individuals with chronic SCI as compared to uninjured individuals. Here, we describe the relative frequencies of T cell populations in individuals with chronic SCI as compared to uninjured individuals. We show that the frequency of CD3+ and CD3+ CD4+ T cells are decreased in individuals with chronic SCI, although activated (HLA-DR+) CD4+ T cells are elevated in chronic SCI. We also examined regulatory T cells (Tregs), defined as CD3+ CD4+ CD25+ CD127lo and CCR4+, HLA-DR+ or CCR4+ HLA-DR+. To our knowledge, we provide the first evidence that CCR4+, HLA-DR+ or CCR4+ HLA-DR+ Tregs are expanded in individuals with SCI. These data support additional functional studies of T cells isolated from individuals with chronic SCI, where alterations in T cell homeostasis may contribute to immune dysfunction, such as immunity against infections or the persistence of chronic inflammation
An Empirical Study of the Telecommunication and Economic Growth in Nigeria
This study examines the impact of telecommunication on economic growth in Nigeria. The study’s model is based on Solow’s augmented growth theory where labor, capital and technology are the sole determinants of economic growth. Thus, economic growth is estimated through classical least squares and fully modified ordinary least squares techniques co integration and error correction model. The finding shows that labor employed, capital stock, real investment in telecommunication and electricity supply are statistically significant to economic growth in the short run equilibrium in Nigeria. Therefore, positive economic growth is attainable when efficient and well-coordinated policies are implemented on labor productivity, price management, investment promotion and constant electricity supply. The study used GDP as a proxy of economic growth. Secondary data from NBS, CBN and NCC which were corroborated with data from ITU, WTO and World Bank Development Indicators were used for the analysis. Based on established theories, existing empirical studies and available data, six independent variables (Telecommunications revenue, telecommunications Investments, Teledensity, Agriculture, Unemployment and Electricity consumption) were regressed on the dependent variable (GDP) using Multiple Regression Analysis. The study includes labor employed, capital stock, real investment in telecommunication and electricity supply to be the repressors and real economic growth to be the regress and using a time series data from 1999 – 2018
Evidence of constant diversification punctuated by a mass extinction in the African cycads
The recent evidence that extant cycads are not living fossils triggered a renewed search for a better understanding of their evolutionary history. In this study, we investigated the evolutionary diversification history of the genus Encephalartos, a monophyletic cycad endemic to Africa. We found an antisigmoidal pattern with a plateau and punctual explosive radiation. This pattern is typical of a constant radiation with mass extinction. The rate shift that we found may therefore be a result of a rapid recolonization of niches that have been emptied owing to mass extinction. Because the explosive radiation occurred during the transition Pliocene–Pleistocene, we argued that the processes might have been climatically mediated
Job Growth in Early Transition: Comparing Two Paths
Small start-up firms are the engine of job creation in early transition and yet little is known about the characteristics of this new sector. We seek to identify patterns of job growth in this sector in terms of niches left from central planning and ask about differences in job creation across two different transition economies: Estonia, which experienced rapid destruction of the pre-existing firms, and the Czech Republic, which reduced the old sector gradually. We find job growth within industries to be quantitatively more important than job growth due to across-industry reallocation. Furthermore, the industrial composition of startups is strikingly similar in the two countries. We offer convergence to "western" industry firm-size distributions as an explanation. We also find regularities in wage evolution across new and old firms, including small differences in job quality across the two transition paths.http://deepblue.lib.umich.edu/bitstream/2027.42/39888/3/wp503.pd
Diversification into novel habitats in the Africa clade of Dioscorea (Dioscoreaceae): erect habit and elephant's foot tubers
Background: Dioscorea is a widely distributed and highly diversified genus in tropical regions where it is represented by ten main clades, one of which diversified exclusively in Africa. In southern Africa it is characterised by a distinct group of species with a pachycaul or "elephant''s foot" structure that is partially to fully exposed above the substrate. In contrast to African representatives of the genus from other clades, occurring mainly in forest or woodland, the pachycaul taxa and their southern African relatives occur in diverse habitats ranging from woodland to open vegetation. Here we investigate patterns of diversification in the African clade, time of transition from forest to more open habitat, and morphological traits associated with each habitat and evaluate if such transitions have led to modification of reproductive organs and mode of dispersal. Results: The Africa clade originated in the Oligocene and comprises four subclades. The Dioscorea buchananii subclade (southeastern tropical Africa and South Africa) is sister to the East African subclade, which is respectively sister to the recently evolved sister South African (e. g., Cape and Pachycaul) subclades. The Cape and Pachycaul subclades diversified in the east of the Cape Peninsula in the mid Miocene, in an area with complex geomorphology and climate, where the fynbos, thicket, succulent karoo and forest biomes meet. Conclusions: Diversification out of forest is associated with major shifts in morphology of the perennial tuber (specifically an increase in size and orientation which presumably led them to become pachycaul) and rotation of stem (from twining to non-twining). The iconic elephant''s foot morphology, observed in grasslands and thicket biomes, where its corky bark may offer protection against fire and herbivory, evolved since mid Miocene. A shift in pollination trait is observed within the forest, but entry into open habitat does not show association with reproductive morphology, except in the seed wing, which has switched from winged all round the seed margin to just at the base or at the apex of it, or has been even replaced by an elaiosome
A Toy Model for Testing Finite Element Methods to Simulate Extreme-Mass-Ratio Binary Systems
Extreme mass ratio binary systems, binaries involving stellar mass objects
orbiting massive black holes, are considered to be a primary source of
gravitational radiation to be detected by the space-based interferometer LISA.
The numerical modelling of these binary systems is extremely challenging
because the scales involved expand over several orders of magnitude. One needs
to handle large wavelength scales comparable to the size of the massive black
hole and, at the same time, to resolve the scales in the vicinity of the small
companion where radiation reaction effects play a crucial role. Adaptive finite
element methods, in which quantitative control of errors is achieved
automatically by finite element mesh adaptivity based on posteriori error
estimation, are a natural choice that has great potential for achieving the
high level of adaptivity required in these simulations. To demonstrate this, we
present the results of simulations of a toy model, consisting of a point-like
source orbiting a black hole under the action of a scalar gravitational field.Comment: 29 pages, 37 figures. RevTeX 4.0. Minor changes to match the
published versio
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