30,977 research outputs found
Cross-Layer Solutions for Cooperative Medium Access Control Protocols
Get PDFAbstract— Recent studies have shown that designing a Medium Access Control (MAC) protocol combined with a cooperative approach may improve the attainable network throughput, despite reducing the mean packet delay. In this paper we design a MAC scheme adopting cooperative physical layer aided cross-layer techniques. We consider a popular cooperative MAC protocol, namely the CoopMAC technique of Liu et al., which is improved by facilitating cooperative signal combining at the destination and employing two relays in the context of a successive relaying technique. The performance of the proposed scheme is evaluated by Monte-Carlo simulations. We demonstrate that a cross-layer design further improves the performance gain provided by the CoopMAC protocol over that of the legacy 802.11 Distributed Coordination Function (DCF), enhancing both the achievable network throughput and the outage probability
Fig. 1 in Formation Of Inter-Species Links In Ungulates In The Azov-Syvash National Nature Park
No full textFig. 1. Dynamics of quantity of the hoof-animals in the Azov-Syvash National Nature Park in the course of 1928–2018.Published as part of Smagol, V. M., Babich, O. G., Kaminetskyi, V. K., Yarysh, V. L. & Smagol, V. O., 2019, Formation Of Inter-Species Links In Ungulates In The Azov-Syvash National Nature Park, pp. 255-262 in Vestnik Zoologii 53 (3) on page 257, DOI: 10.2478/vzoo-2019-0025, http://zenodo.org/record/645522
An integrated operational system to reduce O&M cost of offshore wind farms
No full textOffshore wind is a relatively new industry and it is generally more expensive to generate electricity than many alternative renewable sources. Operation & Maintenance (O&M) makes up a significant part of the overall cost of running Offshore Wind Turbines (OWT). Since the O&M associated responsibility is shared among turbine manufacturers, wind farm operators and the offshore transmission owners, this has inevitably led to lack of information, duplication of effort and less efficiency. Big data analytics is one great technique that will drive future growth. In this paper, an integrated operational system of offshore wind farm is proposed deploying big data analytics. Firstly, the current state of the O&M of offshore wind farm and the big data analytics are introduced. Afterwards, a predictive maintenance model and a maintenance implementation model are proposed, and an integrated operational system is developed incorporating those two models in order to optimize maintenance planning and implementation. Finally, the possible contribution of such a system to a more effective O&M of offshore wind farm is discussed.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Transport Engineering and Logistic
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
The long-wavelength view of GG Tau A: rocks in the ring world
No full textWe present the first detection of GG Tau A at centimetre wavelengths, made with the Arcminute Microkelvin Imager Large Array at a frequency of 16 GHz (λ = 1.8 cm). The source is detected at >6 σrms with an integrated flux density of S16GHz = 249 ± 45 µJy. We use these new centimetre-wave data, in conjunction with additional measurements compiled from the literature, to investigate the long-wavelength tail of the dust emission from this unusual protoplanetary system. We use an MCMC-based method to determine maximum likelihood parameters for a simple parametric spectral model and consider the opacity and mass of the dust contributing to the microwave emission. We derive a dust mass of Md ~ 0.1 Msun, constrain the dimensions of the emitting region and find that the opacity index at λ > 7 mm is less than unity, implying a contribution to the dust population from grains exceeding ~4 cm in size. We suggest that this indicates coagulation within the GG Tau A system has proceeded to the point where dust grains have grown to the size of small rocks with dimensions of a few centimetres. Considering the relatively young age of the GG Tau association in combination with the low derived disc mass, we suggest that this system may provide a useful test case for rapid core accretion planet formation models
Phytochemical Characterization of Water Avens (Geum rivale L.) Extracts: Structure Assignment and Biological Activity of the Major Phenolic Constituents
Get PDFWater avens (Geum rivale L.) is a common Rosaceae plant widely spread in Europe and North America. It is rich in biologically active natural products, some of which are promising as prospective pharmaceuticals. The extracts of water avens are well known for their triterpenoid metabolites and associated anti-inflammatory, antimicrobial and antioxidant activities. However, the polyphenolic profiles of G. rivale L. are still awaiting complete characterization. Accordingly, the contribution of its individual components to the antioxidant, antibacterial and neuroprotective activity of the extracts is still unknown. As this plant can be available on an industrial scale, a better knowledge of its properly-relevant constituents might give access to new highly-efficient pharmaceutical substances and functional products. Therefore, herein we comprehensively characterize the secondary metabolome of G. rivale by ESI-HR-MS, ESI-HR-MSn and NMR spectroscopy with a special emphasis on the polyphenolic composition of its aerial parts. Furthermore, a multilateral evaluation of the antioxidant, neuroprotective and antibacterial properties of the aqueous and ethyl acetate fractions of the total aqueous alcoholic extract as well as individual isolated polyphenols was accomplished. Altogether four phenolic acid derivatives (trigalloyl hexose, caffeoyl-hexoside malate, ellagic acid and ellagic acid pentoside), six flavonoids (three quercetin derivatives, kaempferol and three its derivatives and two isorhamnetin derivatives) and four tannins (HHDP-hexoside, proantocyanidin dimer, pedunculagin I and galloyl-bis-HHDP-hexose) were identified in this plant for the first time. The obtained aqueous and ethyl acetate fractions of the total extract as well as the isolated individual compounds showed pronounced antioxidant activity. In addition, a pronounced antibacterial activity against several strains was proved for the studied fractions (for ethyl acetate fraction the highest activity against E. coli АТСС 25922 and S. aureus strains ATCC 27853 and SG-511 (MIC 15.6 μg/mL) was observed; for aqueous fraction—against Staphylococcus aureus SG-511 (MIC 31.2 μg/mL)). However, the anti-neurodegenerative (neuroprotective) properties could not be found with the employed methods. However, the antibacterial activity of the fractions could not be associated with any of the isolated individual major phenolics (excepting 3-O-methylellagic acid). Thus, the aerial parts of water avens represent a promising source of polyphenolic compounds with antioxidant activity and therefrom derived human health benefits, although the single constituents isolated so far lack a dominant selectively bioactive constituent in the bioassays performed
Analysis of the prevalence of vitamin D deficiency states among internally displaced persons = Аналіз поширеності вітамін D дефіцитних станів серед внутрішньо переміщених осіб
No full textVastyanov R. S., Babich M. S., Goroshkov O. V., Rozhnova A. M. Analysis of the prevalence of vitamin d deficiency states among internally displaced persons = Аналіз поширеності вітамін d дефіцитних станів серед внутрішньо переміщених осіб \\ Вісник морської медицини / Herald for maritime medicine / 2023;2(99):13-19. ISSN 2707-1324
DOI http://dx.doi.org/10.5281/zenodo.8171221
http://www.medtrans.com.ua
УДК 616.391:577.161.2]-036.2-054.73
DOI http://dx.doi.org/10.5281/zenodo.8171221
Vastyanov R. S., Babich M. S., Goroshkov O. V., Rozhnova A. M.
ANALYSIS OF THE PREVALENCE OF VITAMIN D DEFICIENCY STATES AMONG INTERNALLY DISPLACED PERSONS
Odessa National Medical University,
2Odessa City Clinical Hospital N 11;
e-mail: [email protected].
Vitamin D deficiency is an actual problem all over the world. Every year, statistical data are expanded and detailed. The lack of static data on the prevalence of vitamin D deficiency among internally displaced persons (IDPs) in Ukraine became the basis for this work. Analysis of the prevalence of vitamin D deficiency and insufficiency among internally displaced persons will allow to develop effective and affordable methods of prevention of vitamin D deficiency conditions in this population category. 174 patients (women - 92, men - 82) aged 18 - 79 y. o. (average - 44.4 years) from the Mykolaiv and Kherson regions took part in the study. The study was conducted over 3 May, June, July. As a part of the study, all patients underwent a laboratory examination to determine the level of 25(OH)D in blood serum. According to the results of the study, the following indicators of the initial concentration of 25(OH)D in blood serum were obtained: 31.61% of patients had vitamin D deficiency (DVD), vitamin D insufficiency (NVD) - 45.40%, and a normal level of vitamin D - 22.98% patients The results of the study reflect the significant prevalence of vitamin D deficiency conditions among IDPs and emphasize the need for further study of the problem in order to develop the most affordable and effective methods for the correction and prevention of vitamin D deficiency in extreme conditions.
Key words: vitamin d, internally displaced persons, vitamin d deficiency, prevention, hygienic assessment, population of Ukraine
Р. С. Вастьянов1, М. С. Бабіч2, О. В. Горошков1, А. М. Рожнова1
АНАЛІЗ ПОШИРЕНОСТІ ВІТАМІН D ДЕФІЦИТНИХ СТАНІВ СЕРЕД ВНУТРІШНЬО ПЕРЕМІЩЕНИХ ОСІБ
1Одеський національний медичний університет,
2Одеська міська клінічна лікарня №11
Дефіцит вітаміну D - проблема актуальна у всьому світі. З кожним роком статистичні дані розширюються та деталізуються. Саме відсутність статичних даних щодо поширеності вітамін D дефіцитних станів серед внутрішньо переміщених осіб (ВПО) в Україні стала основою для даної роботи. Аналіз поширеності дефіциту та недостатності вітаміну D серед внутрішньо переміщених осіб дозволить розробити ефективні та доступні методи профілактики вітамін D дефіцитних станів у даній категорії населення. У дослідженні брали участь 174 пацієнта (жінки - 92, чоловіки - 82) у віці від 18 до 79 років (середній вік пацієнтів - 44,4 роки) з Миколаївської та Херсонської областей. Дослідження проводилося протягом 3 місяців (травень, червень, липень). У рамках дослідження усім пацієнтам проведено лабораторне обстеження з визначення рівня 25(ОН)D сироватки крові. За результатами дослідження отримані наступні показники початкової концентрації 25(ОН)D сироватки крові: дефіцит вітаміну D (ДВД) мали 31,61% пацієнтів, недостатність вітаміну D (НВД) - 45,40% та нормальний рівень вітаміну D-22,98% пацієнтів. Результати дослідження відображають значну поширеність вітамін D дефіцитних станів серед ВПО та підкреслюють необхідність подальшого вивчення проблеми для розробки найбільш доступних та ефективних методів корекції і профілактики дефіциту вітаміну D в екстремальних умовах.
Ключові слова: вітамін D, внутрішньо переміщені особи, дефіцит вітаміну D, профілактика, гігієнічна оцінка, населення Україн
DNS of turbulent mixing layers with variable density
No full textWe present some preliminary results of direct numerical simulations of three-dimensional, temporal, plane mixing layers with variable density. The simulations are run with a parallel in-house code that solves the Navier-Stokes equations in the Low-Mach number approximation, using a novel algorithm based on an extended version of the velocity-vorticity formulation used by Kim, Moin & Moser (1987) for incompressible flows. The simulations are run with Pr=0.7 and achieve Re_lambda=90-110 during the self-similar evolution of the mixing layer. Four cases with density ratios s=1,2,4 and 8 are presented. Our results show good agreement with previous experimental and numerical studies, and allow us to characterize the scales in the temperature spectra
Stability in m-quota games
No full textThe abstracts (in two languages) can be found in the pdf file of the article.
Original author name(s) and title in Russian and Lithuanian:
О. Н. Бондарева, Устойчивость в играх с m-квотой
O. Bondareva, Stabilumas lošimuose su m-kvot
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