Застосування висотних платформ та технології OFDM у телекомунікаційних системах 4G

Questions of passing to the telecommunication systems of fourth generation with application of height platforms and technology of OFDM are considered. There are considered of power efficiency of these systems.Рассмотрены вопросы перехода к телекоммуникационным системам четвертого поколения с применением высотных платформ и технологии OFDM. Раскрывается энергетическая эффективность систем.Розглянуті питання переходу до телекомунікаційних систем четвертого покоління із застосуванням висотних платформ та технології OFDM. Розкривається енергетична ефективність таких систем

Методика перестроения маршрута полета воздушного судна в процессе его выполнения

   A significant number of aviation incidents is related to loss of control in flight and controlled flight into terrain (LOC-I, CFIT, LALT categories). Investigation of these aviation incidents has revealed that these incidents often occur due to the need for rapid changes in flight routes as a result of detecting obstacles, such as thunderstorms, along the aircraft's path. During the determination of alternative routes to circumvent the encountered obstacle, as well as during the implementation process of the chosen rerouted route, the flight crew makes errors due to increased psycho-physiological workload and time constraints. This article presents an approach to the automatic rerouting of the aircraft's flight route to avoid obstacles detected during flight. The algorithm proposed by the authors allows for evaluating the safety of the original route, calculating alternative route options to bypass the obstacles encountered during flight, verifying their feasibility considering the aircraft's flight technical characteristics and control parameter limitations, and selecting the optimal rerouted route based on specific criteria, such as minimizing the increase in the flight route length, reducing additional fuel consumption, time required for implementing the new flight route, etc. Examples of rerouting the flight route of a hypothetical aircraft with detected obstacles along the flight path are provided in the article to demonstrate the algorithm's functionality. It is shown, in particular, that in the considered example, the shortest route for obstacle avoidance is not optimal in terms of time. It is also demonstrated that the safety of flying along the identified alternative rerouted routes depends, among other factors, on the selected flight speed. Therefore, for each calculated rerouted route, the algorithm determines a range of speeds within which the implementation of the obtained rerouted route is possible. This highlights the complexity and non-triviality of the pilot's task of autonomously finding a safe obstacle avoidance route on board the aircraft.   Большое количество авиационных происшествий связано с потерей управления в полете, а также со столкновением с землей в управляемом полете (категории LOC-I, CFIT, LALT). В результате расследования данных авиационных происшествий выявлено, что часто указанные авиационные происшествия обусловлены необходимостью быстрого изменения маршрута полета вследствие выявления на пути следования воздушного судна препятствий, например, грозового фронта. При определении альтернативных маршрутов облета возникшего препятствия, а также впроцессе реализации выбранного маршрута облета экипаж совершает ошибки ввиду повышенной психофизиологической нагрузки и дефицита времени. В данной статье представлен подход к автоматическому перестроению маршрута полета воздушного судна для облета обнаруженных в процессе полета препятствий. Предлагаемый авторами алгоритм позволяет оценить безопасность исходного маршрута, рассчитать варианты альтернативных маршрутов облета обнаруженных впроцессе полета препятствий, проверить их на реализуемость с учетом летно-технических характеристик воздушного судна, ограничений на управляющие параметры, а также выбрать среди найденных маршрутов облета оптимальный с точки зрения какого-либо критерия, например, исходя из минимизации увеличения протяженности маршрута полета, сокращения дополнительных затрат топлива, времени, необходимого на реализацию нового маршрута полета, и т. д. Для демонстрации работоспособности алгоритма в статье представлены примеры перестроения маршрута полета гипотетического воздушного судна с выявленными на пути следования препятствиями. Показано, в частности, что в рассмотренном примере самый короткий маршрут облета препятствий не является оптимальным с точки зрения временных затрат. Также демонстрируется, что безопасность пролета по найденным альтернативным маршрутам облета препятствий зависит в том числе от выбранной скорости полета. Поэтому для каждого рассчитанного маршрута облета препятствий алгоритм определяет диапазон скоростей, в котором возможна реализация полученного маршрута облетапрепятствий. Последнее указывает на сложность и нетривиальность самостоятельного решения задачи поиска безопасного маршрута облета препятствий пилотом на борту воздушного судна

International Terrorism in the Context of the Modern World Order

В статье анализируются аспекты зарождения и распространения терроризма, его негативное влияние на внутригосударственные и международные процессы, характеризуется идеологическая основа терроризма.The article analyzes aspects of the spread of terrorism around the world, its negative impact on domestic and international processes, characterizes the ideological basis of terrorism

Влияние климатических изменений на глубину промерзания почв в бассейне р. Волга

It is established that the climate warming leads to decrease in depth of soil freezing in the whole area basin of the River Volga. This effect is observed since 1978. Depths of soil freezing averaged over the whole basin decreased relative to values measured during the period of stable climate conditions by 34 cm, i.e. from 92 up to 58 cm, or by 37%. In the Northern part of the basin, the depths have decreased by 49%, in the Western, Eastern, and Southern areas – 39, 24 and 38%, respectively. The spatial variability of the depths is estimated by the example of the river Vyatka, the large tributary of the Volga with area of 124 000 km2 and the site «Log Usadjevsky» with area of 2.0 km2 (a part of experimental polygon of the Valdai waterbalance station). It is shown that the coefficient of variation of the freezing depth decreases when the depth increases. When the depth becomes smaller 60 cm plots of thawed soil appear that significantly increases the infiltration ability of the basin. The technique of estimating the soil freezing depth under change of climate characteristics is proposed.Рассмотрена временная изменчивость глубин промерзания почвы, обусловленная вариабельностью климатических характеристик в бассейне р. Волга. Показано, что изменение глубин промерзания наблюдается во всём бассейне реки, но имеются опредёленные отличия в каждой из её географических зон. Оценены пространственная изменчивость глубин промерзания на примере бассейна р. Вятка и водосборов малых рек, а также возможность прогноза промерзания почв при климатических изменениях

Inhibition of DAGLβ as a therapeutic target for pain in sickle cell disease

Sickle cell disease (SCD) is the most common inherited disease. Pain is a key morbidity of SCD and opioids are the main treatment but their side effects emphasize the need for new analgesic approaches. Humanized transgenic mouse models have been instructive in understanding the pathobiology of SCD and mechanisms of pain. Homozygous (HbSS) Berkley mice express >99% human sickle hemoglobin and several features of clinical SCD including hyperalgesia. Previously, we reported that the endocannabinoid 2-arachidonoylglycerol (2-AG) is a precursor of the pro-nociceptive mediator prostaglandin E2-glyceryl ester (PGE2-G) which contributes to hyperalgesia in SCD. We now demonstrate the causal role of 2-AG in hyperalgesia in sickle mice. Hyperalgesia in HbSS mice correlated with elevated levels of 2-AG in plasma, its synthesizing enzyme diacylglycerol lipase β (DAGLβ) in blood cells, and with elevated levels of PGE2 and PGE2-G, pronociceptive derivatives of 2-AG. A single intravenous injection of 2-AG produced hyperalgesia in non-hyperalgesic HbSS mice, but not in control (HbAA) mice expressing normal human HbA. JZL184, an inhibitor of 2-AG hydrolysis, also produced hyperalgesia in non-hyperalgesic HbSS or hemizygous (HbAS) mice, but did not influence hyperalgesia in hyperalgesic HbSS mice. Systemic and intraplantar administration of KT109, an inhibitor of DAGLβ, decreased mechanical and heat hyperalgesia in HbSS mice. The decrease in hyperalgesia was accompanied by reductions in 2-AG, PGE2 and PGE2-G in the blood. These results indicate that maintaining the physiological level of 2-AG in the blood by targeting DAGLβ may be a novel and effective approach to treat pain in SCD

The monoclonal antibody EPR1614Y against the stem cell biomarker keratin K15 lacks specificity and reacts with other keratins

Keratin 15 (K15), a type I keratin, which pairs with K5 in epidermis, has been used extensively as a biomarker for stem cells. Two commercial antibodies, LHK15, a mouse monoclonal and EPR1614Y, a rabbit monoclonal, have been widely employed to study K15 expression. Here we report differential reactivity of these antibodies on epithelial cells and tissue sections. Although the two antibodies specifically recognised K15 on western blot, they reacted differently on skin sections and cell lines. LHK15 reacted in patches, whereas EPR1614Y reacted homogenously with the basal keratinocytes in skin sections. In cultured cells, LHK15 did not react with K15 deficient NEB-1, KEB-11, MCF-7 and SW13 cells expressing only exogenous K8 and K18 but reacted when these cells were transduced with K15. On the other hand, EPR1614Y reacted with these cells even though they were devoid of K15. Taken together these results suggest that EPR1614Y recognises a conformational epitope on keratin filaments which can be reconstituted by other keratins as well as by K15. In conclusion, this report highlights that all commercially available antibodies may not be equally specific in identifying the K15 positive stem cell

Surface Doping Quantum Dots with Chemically Active Native Ligands: Controlling Valence without Ligand Exchange

One remaining challenge in the field of colloidal semiconductor nanocrystal quantum dots is learning to control the degree of functionalization or valence per nanocrystal. Current quantum dot surface modification strategies rely heavily on ligand exchange, which consists of replacing the nanocrystal\u27s native ligands with carboxylate- or amine-terminated thiols, usually added in excess. Removing the nanocrystal\u27s native ligands can cause etching and introduce surface defects, thus affecting the nanocrystal\u27s optical properties. More importantly, ligand exchange methods fail to control the extent of surface modification or number of functional groups introduced per nanocrystal. Here, we report a fundamentally new surface ligand modification or doping approach aimed at controlling the degree of functionalization or valence per nanocrystal while retaining the nanocrystal\u27s original colloidal and photostability. We show that surface-doped quantum dots capped with chemically active native ligands can be prepared directly from a mixture of ligands with similar chain lengths. Specifically, vinyl and azide-terminated carboxylic acid ligands survive the high temperatures needed for nanocrystal synthesis. The ratio between chemically active and inactive-terminated ligands is maintained on the nanocrystal surface, allowing to control the extent of surface modification by straightforward organic reactions. Using a combination of optical and structural characterization tools, including IR and 2D NMR, we show that carboxylates bind in a bidentate chelate fashion, forming a single monolayer of ligands that are perpendicular to the nanocrystal surface. Moreover, we show that mixtures of ligands with similar chain lengths homogeneously distribute themselves on the nanocrystal surface. We expect this new surface doping approach will be widely applicable to other nanocrystal compositions and morphologies, as well as to many specific applications in biology and materials science

Molecular Chemistry to the Fore: New Insights into the Fascinating World of Photoactive Colloidal Semiconductor Nanocrystals

Colloidal semiconductor nanocrystals possess unique properties that are unmatched by other chromophores such as organic dyes or transition-metal complexes. These versatile building blocks have generated much scientific interest and found applications in bioimaging, tracking, lighting, lasing, photovoltaics, photocatalysis, thermoelectrics, and spintronics. Despite these advances, important challenges remain, notably how to produce semiconductor nanostructures with predetermined architecture, how to produce metastable semiconductor nanostructures that are hard to isolate by conventional syntheses, and how to control the degree of surface loading or valence per nanocrystal. Molecular chemists are very familiar with these issues and can use their expertise to help solve these challenges. In this Perspective, we present our group\u27s recent work on bottom-up molecular control of nanoscale composition and morphology, low-temperature photochemical routes to semiconductor heterostructures and metastable phases, solar-to-chemical energy conversion with semiconductor-based photocatalysts, and controlled surface modification of colloidal semiconductors that bypasses ligand exchange

A niche remedy for the dynamical problems of neutral theory

We demonstrate how niche theory and Hubbell's original formulation of neutral theory can be blended together into a general framework modeling the combined effects of selection, drift, speciation, and dispersal on community dynamics. This framework connects many seemingly unrelated ecological population models, and allows for quantitative predictions to be made about the impact of niche stabilizing and destabilizing forces on population extinction times and abundance distributions. In particular, the existence of niche stabilizing forces in our blended framework can simultaneously resolve two major problems with the dynamics of neutral theory, namely predictions of species lifetimes that are too short and species ages that are too long.Comment: 47 pages, 4 figures, Accepted to Theoretical Ecolog