31 research outputs found
Pair Plasma Cascade in Rotating Black Hole Magnetospheres with Split Monopole Flux Model
An electron-positron cascade in the magnetospheres of Kerr Black Holes (BH)
is a fundamental ingredient to fueling the relativistic -ray jets seen
at the polar regions of galactic supermassive BHs (SMBH). This leptonic cascade
occurs in the "spark gap" region of a BH magnetosphere where the unscreen
electric field parallel to the magnetic field is present, hence it is affected
by the magnetic field structure. A previous study explored the case of a thin
accretion disk, representative of Active Galactic Nuclei (AGN). Here we explore
the case of a quasi-spherical gas distribution, as is expected to be present
around the SMBH Sgr A* in the center of our Milky Way galaxy, for example. The
properties and efficiency of the leptonic cascade are studied. The findings of
our study and the implications for SMBH systems in various spectral and
accretion states are discussed. The relationships and scalings derived from
varying the mass of the BH and background photon spectra are further used to
analyze the leptonic cascade process to power jets seen in astronomical
observations. In particular, one finds the efficiency of the cascade in a
quasi-spherical gas distribution peaks at the jet axis. Observationally, this
should lead to a more prominent jet core, in contrast to the thin disk
accretion case, where it peaks around the jet-disk interface. One also finds
the spectrum of the background photons to play a key role. The cascade
efficiency is maximum for a spectral index of two, while harder and softer
spectra lead to a less efficient cascade.Comment: 28 pages, 14 figures, accepted to ApJ 28/10/202
Accurate and exact CNV identification from targeted high-throughput sequence data
<p>Abstract</p> <p>Background</p> <p>Massively parallel sequencing of barcoded DNA samples significantly increases screening efficiency for clinically important genes. Short read aligners are well suited to single nucleotide and indel detection. However, methods for CNV detection from targeted enrichment are lacking. We present a method combining coverage with map information for the identification of deletions and duplications in targeted sequence data.</p> <p>Results</p> <p>Sequencing data is first scanned for gains and losses using a comparison of normalized coverage data between samples. CNV calls are confirmed by testing for a signature of sequences that span the CNV breakpoint. With our method, CNVs can be identified regardless of whether breakpoints are within regions targeted for sequencing. For CNVs where at least one breakpoint is within targeted sequence, exact CNV breakpoints can be identified. In a test data set of 96 subjects sequenced across ~1 Mb genomic sequence using multiplexing technology, our method detected mutations as small as 31 bp, predicted quantitative copy count, and had a low false-positive rate.</p> <p>Conclusions</p> <p>Application of this method allows for identification of gains and losses in targeted sequence data, providing comprehensive mutation screening when combined with a short read aligner.</p
Cytokine biomarkers and chronic pain: Association of genes, transcription, and circulating proteins with temporomandibular disorders and widespread palpation tenderness
For reasons unknown, temporomandibular disorder (TMD) can manifest as localized pain or in conjunction with widespread pain. We evaluated relationships between cytokines and TMD without or with widespread palpation tenderness (TMD−WPT or TMD+WPT, respectively), at protein, transcription factory activity, and gene levels. Additionally, we evaluated the relationship between cytokines and intermediate phenotypes characteristic of TMD and WPT. In a case-control study of 344 females, blood samples were analyzed for levels of 22 cytokines and activity of 48 transcription factors. Intermediate phenotypes were measured by quantitative sensory testing and questionnaires asking about pain, health, and psychological status. Single nucleotide polymorphisms (SNPs) coding cytokines and transcription factors were genotyped. TMD−WPT cases had elevated protein levels of pro-inflammatory cytokine MCP-1 and anti-inflammatory cytokine IL-1ra, whereas TMD+WPT cases had elevated levels of pro-inflammatory cytokine IL-8. MCP-1, IL-1ra, and IL-8 were differentially associated with experimental pain, self-rated pain, self-rated health, and psychological phenotypes. TMD−WPT and TMD+WPT cases had inhibited transcription activity of the anti-inflammatory cytokine TGFβ1. Interactions were observed between TGFβ1 and IL-8 SNPs: an additional copy of the TGFβ1 rs2241719 minor T allele was associated with twice the odds of TMD+WPT among individuals homozygous for the IL-8 rs4073 major A allele and half the odds of TMD+WPT among individuals heterozygous for rs4073. These results demonstrate how pro- and anti-inflammatory cytokines contribute to the pathophysiology of TMD and WPT in genetically-susceptible people. Furthermore, they identify MCP-1, IL-1ra, IL-8, and TGFβ1 as potential diagnostic markers and therapeutic targets for pain in patients with TMD
Is computational oceanography coming of age?
Computational oceanography is the study of ocean phenomena by numerical simulation, especially dynamical and physical phenomena. Progress in information technology has driven exponential growth in the number of global ocean observations and the fidelity of numerical simulations of the ocean in the past few decades. The growth has been exponentially faster for ocean simulations, however. We argue that this faster growth is shifting the importance of field measurements and numerical simulations for oceanographic research. It is leading to the maturation of computational oceanography as a branch of marine science on par with observational oceanography. One implication is that ultraresolved ocean simulations are only loosely constrained by observations. Another implication is that barriers to analyzing the output of such simulations should be removed. Although some specific limits and challenges exist, many opportunities are identified for the future of computational oceanography. Most important is the prospect of hybrid computational and observational approaches to advance understanding of the ocean
Modelling long term effects of cropping and managements systems on soil organic matter, C/N dynamics and crop growth
While simulation of cropping systems over a few years might reflect well the short term effects of management and cultivation, long term effects on soil properties and their consequences for crop growth and matter fluxes are not captured. Especially the effect on soil carbon sequestration/depletion is addressed by this task. Simulations of an ensemble of crop models are performed as transient runs over a period of 120 year using observed weather from three stations in Czech Republic (1961-2010) and transient long time climate change scenarios (2011-2080) from five GCM of the CMIP5 ensemble to assess the effect of different cropping and management systems on carbon sequestration, matter fluxes and crop production in an integrative way. Two cropping systems are regarded comprising two times winter wheat, silage maize, spring barley and oilseed rape. Crop rotations differ regarding their organic input from crop residues, nitrogen fertilization and implementation of catch crops. Models are applied for two soil types with different water holding capacity. Cultivation and nutrient management is adapted using management rules related to weather and soil conditions. Data of phenology and crop yield from the region of the regarded crops were provided to calibrate the models for crops of the rotations. Twelve models were calibrated in this first step. For the transient long term runs results of four models were submitted so far. Outputs are crop yields, nitrogen uptake, soil water and mineral nitrogen contents, as well as water and nitrogen fluxes to the atmosphere and groundwater. Changes in the carbon stocks and the consequences for nitrogen mineralisation, N fertilization and emissions also considered.
Розробка розміростабільних схем багатошарових трубопроводів і циліндричних посудин тиску з вуглепластиків
In the framework of the momentless theory of cylindrical thin shells, the elastic deformation of multilayer pipes and pressure vessels is investigated. It is assumed that the pipes and pressure vessels are made by two-way spiral winding of carbon fiber reinforced plastic tape on a metal mandrel.The analysis of the dependences of elastic deformations on the reinforcement angles is performed. The relations for axial and circumferential deformations of the wall, depending on the structure of the layer package, reinforcement angles under static loading are obtained. The separate and combined effect of internal pressure and temperature is considered. For the separate effect of loads, the graphs of deformations against the winding angle are plotted.Composite pipes made of KMU-4L carbon fiber reinforced plastic, as well as composite metal-composite pipes, are investigated. The results obtained for thermal loads are in good agreement with the data of the known experiment and solution. Depending on the load parameters, composite and metal-composite structures with dimensionally stable properties are determined.It is shown that dimensionally stable structures can be used to solve the problem of compensation of elastic deformations of pipelines. For this purpose, using the ASCP software package, the variant analysis of model structures is performed. By the comparative analysis of the three versions of the structure, layer package structures and reinforcement schemes, ensuring a significant reduction of loads on the supporting elements are obtained. On the example of a pipeline with a flowing fluid, it is shown that the use of dimensionally stable multilayer pipes makes it possible to eliminate bending deformations and significantly reduce the level of working forces and stresses.Dimensionally stable composite multilayer pipes open up new approaches to the design of pipelines and pressure vessels. It is possible to create structures with predetermined (not necessarily zero) displacement fields, consistent with the fields of the initial technological displacements, as well as with the displacements of conjugate elastic elements and equipment when the operating mode changes. The scope of such structures is not limited to "hot" pipes. The results can be used in cryogenic engineeringВ рамках безмоментной теории цилиндрических тонких оболочек исследовано упругое деформирование многослойных труб и сосудов давления. Предполагается, что трубы и сосуды давления выполнены перекрестной спиральной намоткой армированной ленты из углепластика на металлическую оправку.Выполнен анализ зависимостей упругих деформаций от углов армирования. Получены соотношения для осевых и окружных деформаций стенки в зависимости от структуры пакета слоев, углов армирования при статическом нагружении. Рассмотрено обособленное и комбинированное действие внутреннего давления и температуры. Для обособленного действия нагрузок построены графики зависимостей деформаций от угла намотки.Исследованы композитные трубы, изготовленные из углепластика[s1] KМУ-4Л, а также составные металло-композитные трубы. Результаты, полученные для тепловых нагрузок, хорошо согласуются с данными известного эксперимента и решения. В зависимости от параметров нагрузок определены композитные и металло-композитные структуры с размеростабильными свойствами.Показано, что размеростабильные структуры могут быть использованы для решения проблемы компенсации упругих деформаций трубопроводов. С этой целью при помощи программного комплекса ASCP выполнен вариантный анализ модельной конструкций. Путем сопоставительного анализа трех вариантов конструкции получены структуры пакетов слоев и схемы армирования, обеспечивающие значительное снижение нагрузок на опорные элементы. На примере трубопровода с протекающей жидкостью показано, что применение размеростабильных многослойных труб позволяет исключить деформации изгиба и заметно понизить уровень рабочих усилий и напряжений.Размеростабильные многослойные трубы из композитов открывают новые подходы к проектированию трубопроводов и сосудов под давлением. Появляются возможности создания конструкций с наперед заданными (не обязательно нулевыми) полями перемещений, согласованными с полями начальных технологических перемещений, а также с перемещениями сопряженных упругих элементов и оборудования при изменении режима работы. Область применения подобных конструкций не ограничивается "горячими" трубами. Полученные результаты могут найти применение в криогенной технике В рамках безмоментної теорії циліндричних тонких оболонок досліджено пружне деформування багатошарових труб і посудин тиску. Передбачається, що труби і посудини тиску виконані перехресної спіральної намотуванням армованої стрічки з вуглепластика на металеву оправлення.Виконано аналіз залежностей пружних деформацій від кутів армування. Отримано співвідношення для осьових і окружних деформацій стінки в залежності від структури пакета шарів, кутів армування при статичному навантаженні. Розглянуто відокремлена і комбінована дія внутрішнього тиску і температури. Для відокремленої дії навантажень побудовані графіки залежностей деформацій від кута намотування.Досліджено композитні труби, виготовлені з вуглепластика KМУ-4Л, а також складові метало-композитні труби. Результати, отримані для теплових навантажень, добре узгоджуються з даними відомого експерименту і рішення. Залежно від параметрів навантажень визначені композитні та метало-композитні структури з розміростабільними властивостями.Показано, що розміростабільні структури можуть бути використані для вирішення проблеми компенсації пружних деформацій трубопроводів. З цією метою за допомогою програмного комплексу ASCP виконаний варіантний аналіз модельної конструкції. Шляхом порівняльного аналізу трьох варіантів конструкції отримані структури пакетів шарів і схеми армування, щоб забезпечити значне зниження навантажень на опорні елементи. На прикладі трубопроводу з протікаючою рідиною показано, що застосування розміростабільних багатошарових труб дозволяє виключити деформації вигину і помітно знизити рівень робочих зусиль і напружень.Розміростабільні багатошарові труби з композитів відкривають нові підходи до проектування трубопроводів і посудин під тиском. З'являються можливості створення конструкцій з наперед заданими (не обов'язково нульовими) полями переміщень, узгодженими з полями початкових технологічних переміщень, а також з переміщеннями сполучених пружних елементів і устаткування при зміні режиму роботи. Область застосування подібних конструкцій не обмежується «гарячими» трубами. Отримані результати можуть знайти застосування в кріогенній техніц
Comparative Simulation of Various Agricultural Land Use Practices for Analysis of Impacts on Environments
Current intensification and changes in agricultural land use practices increase environmental impact that can be reduced by bridging the gap between socio-economic demands and scientific justification of sustainable agricultural land use. This can be achieved by replacing the goal of maximum crop yields with the goal of minimal environmental impact. This paper presents results of integrated crop simulation system development for analysis of alternative planning strategies in agricultural land use, with focus on the crop rotation influence on environmental sustainability. The effective tools used in analysis include (1) long-term analysis of changes in agricultural land using a dynamic crop model with daily time step; (2) justification of arbitrary crop rotation scheme of different agro-technologies and sparing measures; and (3) analysis of modern farming management methods using model-oriented approach. The results of study also include estimation of two alternative practices of crop harvesting including remaining or removing whole crop residues from the agricultural field and their influence on basic parameters of soil fertility. In addition, we analyzed comparative efficiency of different agricultural measures neglecting the negative influence of possible climate changes in long-term consequences. Corresponding efficiency rating is the following: organic fertilizer, green manure legume sparing harvesting, winter catch crop, and rotation scheme