Cosmic Rays at the highest energies

After a century of observations, we still do not know the origin of cosmic rays. I will review the current state of cosmic ray observations at the highest energies, and their implications for proposed acceleration models and secondary astroparticle fluxes. Possible sources have narrowed down with the confirmation of a GZK-like spectral feature. The anisotropy observed by the Pierre Auger Observatory may signal the dawn of particle astronomy raising hopes for high energy neutrino observations. However, composition related measurements point to a different interpretation. A clear resolution of this mystery calls for much larger statistics than the reach of current observatories.Comment: 8 pages, 4 figures, in the Proceedings of TAUP 201

INVESTMENT PROGRAM OF POWER GRID COM PANIES: CHECK ALL CAN NOT BE SELECTED

Starting in 2017, the carrying out of technological and price audit of investment programs (projects of investment programs) and reports on their implementation has been secured as the necessary measures for the electric grid companies of Russia in the framework of approval procedures and approval of investment programs and oversee their implementation.Realization of technological and price audit requires to review large set of information in short period of time, which is limited by investment program validation procedures. Forming representative sample (which describes general population accurately) as an object of analysis could increase audit efficiency. The approach shown in the article is based on mathematical methods of analysis.On the example of the project of the investment program of PJSC "MOESK" the authors made an attempt to apply the described technique. This technique made it possible to perform the main task - the formation of a sample of investment projects, which allows without loss of quality and complexity of the investment program materials to preserve the validity and objectivity of the formed conclusion based on the results of technological and price audit

THE EFFECT OF EXOGENOUS FACTORS ON THERMAL POWER PLANT EFFICIENCY

This study focuses on the relationship between exogenous factors (that cannot be directly impacted by the actions of an economic agent) and combined heat and power (CHP) plant efficiency. As a measure of fuel utilization efficiency this paper proposes to use the Сoefficient of Fuel Utilization (CFU), which is the Russian equivalent of the Primary Energy Factor indicator. Climate conditions and fuel type were used as the exogenous factors in this article. Climate conditions were measured via climate zone proxies. The cause-effect relationships were analyzed using a linear regression model. The findings of the study showcase that the plants, which use natural gas as their primary fuel, show higher fuel utilization efficiency compared to coil plants. Climate conditions were also proven to be a statistically significant factor with plants situated in the third climate zone (mostly regions of the Central and North-Western federal districts) showing the highest average CFU of about 71%. The research shows that the exogenous factors account for close to 20% of CHP plant fuel utilization efficiency in Russia. The authors conclude that climate conditions and fuel type should be taken into account when constructing various energy efficiency models applicable to the Russian context

Limits on models of the ultrahigh energy cosmic rays based on topological defects

An erratum exists for this article. Please see the description link below for details.Using the propagation of ultrahigh energy nucleons, photons, and electrons in the universal radiation backgrounds, we obtain limits on the luminosity of topological defect scenarios for the origin of the highest energy cosmic rays. The limits are set as a function of the mass of the X particles emitted by the cosmic strings or other defects, the cosmological evolution of the topological defects, and the strength of the extragalactic magnetic fields. The existing data on the cosmic ray spectrum and on the isotropic 100 MeV gamma-ray background limit significantly the parameter space in which topological defects can generate the flux of the highest energy cosmic rays, and rule out models with the standard X-particle mass of 10¹⁶GeV and higher.R. J. Protheroe and Todor Stane

Optical Properties of Deep Ice at the South Pole - Absorption

We discuss recent measurements of the wavelength-dependent absorption coefficients in deep South Pole ice. The method uses transit time distributions of pulses from a variable-frequency laser sent between emitters and receivers embedded in the ice. At depths of 800 to 1000 m scattering is dominated by residual air bubbles, whereas absorption occurs both in ice itself and in insoluble impurities. The absorption coefficient increases approximately exponentially with wavelength in the measured interval 410 to 610 nm. At the shortest wavelength our value is about a factor 20 below previous values obtained for laboratory ice and lake ice; with increasing wavelength the discrepancy with previous measurements decreases. At around 415 to 500 nm the experimental uncertainties are small enough for us to resolve an extrinsic contribution to absorption in ice: submicron dust particles contribute by an amount that increases with depth and corresponds well with the expected increase seen near the Last Glacial Maximum in Vostok and Dome C ice cores. The laser pulse method allows remote mapping of gross structure in dust concentration as a function of depth in glacial ice.Comment: 26 pages, LaTex, Accepted for publication in Applied Optics. 9 figures, not included, available on request from [email protected]

ИНВЕСТПРОГРАММА СЕТЕЙ: ПРОВЕРИТЬ ВСЕ НЕЛЬЗЯ ОТОБРАТЬ

Starting in 2017, the carrying out of technological and price audit of investment programs (projects of investment programs) and reports on their implementation has been secured as the necessary measures for the electric grid companies of Russia in the framework of approval procedures and approval of investment programs and oversee their implementation.Realization of technological and price audit requires to review large set of information in short period of time, which is limited by investment program validation procedures. Forming representative sample (which describes general population accurately) as an object of analysis could increase audit efficiency. The approach shown in the article is based on mathematical methods of analysis.On the example of the project of the investment program of PJSC "MOESK" the authors made an attempt to apply the described technique. This technique made it possible to perform the main task - the formation of a sample of investment projects, which allows without loss of quality and complexity of the investment program materials to preserve the validity and objectivity of the formed conclusion based on the results of technological and price audit.Начиная с 2017 года проведение технологического и ценового аудита инвестиционных программ (проектов инвестиционных программ) и отчетов об их реализации закреплено в качестве необходимого мероприятия для электросетевых организаций России в рамках процедур согласования и утверждения инвестиционных программ и осуществления контроля за их реализацией.Проведение технологического и ценового аудита (ТЦА) предусматривает обработку большого массива информации в условиях ограниченного (процедурными сроками утверждения инвестиционных программ) временного ресурса. Для повышения эффективности процедур в качестве объекта анализа можно принять не генеральную совокупность (все проекты инвестиционной программы), а сформированную для решения данной задачи соответствующую репрезентативную выборку анализируемых объектов. Предлагается подход формирования такой выборки на основе математических методов анализа.На примере проекта инвестиционной программы ПАО «МОЭСК» авторами предпринята попытка применить предлагаемый подход. Он позволил выполнить основную задачу – формирование выборки инвестиционных проектов, позволяющей без потери качества и комплексности проработки материалов инвестиционной программы сохранить обоснованность и объективность формируемого заключения по результатам ТЦА

ВЛИЯНИЕ ЭКЗОГЕННЫХ ФАКТОРОВНА ЭФФЕКТИВНОСТЬ ДЕЯТЕЛЬНОСТИ ТЕПЛОВЫХ ЭЛЕКТРОСТАНЦИЙ

This study focuses on the relationship between exogenous factors (that cannot be directly impacted by the actions of an economic agent) and combined heat and power (CHP) plant efficiency. As a measure of fuel utilization efficiency this paper proposes to use the Сoefficient of Fuel Utilization (CFU), which is the Russian equivalent of the Primary Energy Factor indicator. Climate conditions and fuel type were used as the exogenous factors in this article. Climate conditions were measured via climate zone proxies. The cause-effect relationships were analyzed using a linear regression model. The findings of the study showcase that the plants, which use natural gas as their primary fuel, show higher fuel utilization efficiency compared to coil plants. Climate conditions were also proven to be a statistically significant factor with plants situated in the third climate zone (mostly regions of the Central and North-Western federal districts) showing the highest average CFU of about 71%. The research shows that the exogenous factors account for close to 20% of CHP plant fuel utilization efficiency in Russia. The authors conclude that climate conditions and fuel type should be taken into account when constructing various energy efficiency models applicable to the Russian context.Объектом исследования являетсявлияние экзогенных факторов (на которые хозяйственный субъект не может воздействовать напрямую) на показатели эффективности отечественных тепловых электростанций. В качестве показателя эффективности топливоиспользования применен коэффициент использования топлива. В качестве экзогенных факторов приняты климатические условия и вид используемого на станциях топлива. Климатические условиявыражены с помощью климатических зон.Анализ причинно-следственных связей между экзогенными факторами и эффективностью станций был проведен с помощью линейной регрессионной модели.Станции, использующие природный газ в качестве основного вида топлива, оказались более эффективны по сравнению со станциями, потребляющими угольное топливо. Статистическая значимость климатического фактора выражена в том, что наивысший коэффициент использования топлива (порядка 71%) имеютстанции, расположенные в третьей климатической зоне (преимущественно в Центральном и Северо-Западном федеральных округах). Рассмотренные экзогенные факторы примерно на 20% объясняют эффективность топливоиспользования на отечественных тепловых электростанциях. Данные факторы необходимо учитывать при построении аналитических моделей для изученияэнергоэффективности отечественных электростанций.

Fecal Microbial Communities in a Large Representative Cohort of California Dairy Cows

Improved sequencing and analytical techniques allow for better resolution of microbial communities; however, the agriculture field lacks an updated analysis surveying the fecal microbial populations of dairy cattle in California. This study is a large-scale survey to determine the composition of the bacterial community present in the feces of lactating dairy cattle on commercial dairy operations. For the study, 10 dairy farms across northern and central California representing a variety of feeding and management systems were enrolled. The farms represented three typical housing types including five freestall, two drylot and three pasture-based management systems. Fresh feces were collected from 15 randomly selected cows on each farm and analyzed using 16S rRNA gene amplicon sequencing. This study found that housing type, individual farm, and dietary components significantly affected the alpha diversity of the fecal microbiota. While only one Operational Taxonomic Unit (OTU) was common among all the sampled individuals, 15 bacterial families and 27 genera were shared among 95% of samples. The ratio of the families Coriobacteriaceae to Bifidobacteriaceae was significantly different between housing types and farms with pasture fed animals having a higher relative abundance of Coriobacteriaceae. A majority of samples were positive for at least one OTU assigned to Enterobacteriaceae and 31% of samples contained OTUs assigned to Campylobacter. However, the relative abundance of both taxa was <0.1%. The microbial composition displays individual farm specific signatures, but housing type plays a role. These data provide insights into the composition of the core fecal microbiota of commercial dairy cows in California and will further generate hypotheses for strategies to manipulate the microbiome of cattle