217 research outputs found
Long-term evolution of broken wakefields in finite radius plasmas
A novel effect of fast heating and charging a finite-radius plasma is
discovered in the context of plasma wakefield acceleration. As the plasma wave
breaks, the most of its energy is transferred to plasma electrons which create
strong charge-separation electric field and azimuthal magnetic field around the
plasma. The slowly varying field structure is preserved for hundreds of
wakefield periods and contains (together with hot electrons) up to 80% of the
initial wakefield energy.Comment: 5 pages, 6 figure
Numerical Studies of Electron Acceleration Behind Self-Modulating Proton Beam in Plasma with a Density Gradient
Presently available high-energy proton beams in circular accelerators carry
enough momentum to accelerate high-intensity electron and positron beams to the
TeV energy scale over several hundred meters of the plasma with a density of
about 1e15 1/cm^3. However, the plasma wavelength at this density is 100-1000
times shorter than the typical longitudinal size of the high-energy proton
beam. Therefore the self-modulation instability (SMI) of a long (~10 cm) proton
beam in the plasma should be used to create the train of micro-bunches which
would then drive the plasma wake resonantly. Changing the plasma density
profile offers a simple way to control the development of the SMI and the
acceleration of particles during this process. We present simulations of the
possible use of a plasma density gradient as a way to control the acceleration
of the electron beam during the development of the SMI of a 400 GeV proton beam
in a 10 m long plasma. This work is done in the context of the AWAKE project
--- the proof-of-principle experiment on proton driven plasma wakefield
acceleration at CERN.Comment: 4 pages, 5 figures
Investigation of the Heating Processes and Temperature Field of the Frequency-controlled Asynchronous Engine Based on Mathematical Models
The study of the temperature field of the engine for non-stationary modes is done. A numerical simulation of a non-stationary thermal process using dynamic EHD, the characteristic of the rate of rise of temperatures is done. An increase in the temperature of individual parts in the idle interval, when the power of heat release is significantly reduced, is established, and the reverse of the heat flow through the air gap is established. It is shown that the EHD method, in contrast to the FEM, is self-sufficient, which determines its practical value. In various parts of the speed control range in the implementation of various laws of regulation. At the same time, the main electrical, magnetic and additional losses associated with the fundamental voltage harmonics (FVH), and mechanical losses, as well as additional electrical and magnetic losses associated with the higher voltage harmonics, change. When using serial asynchronous engines as frequency-controlled. Permissible under the conditions of heating power is significantly reduced by the power of serial engines. Depending on the synchronous speed, the reduction is from 10 % to 20 %. Given the additional overheating due to higher voltage harmonics, as well as the deterioration of the cooling conditions when adjusting the rotational speed "down" from the nominal, it seems very relevant
α-Latrotoxin receptor Implications in nerve terminal function
Abstractα-Latrotoxin is a potent stimulator of neurotransmitter release from nerve terminals. High affinity membrane α-latrotoxin receptor was purified in an active binding form. It is a membrane glycoprotein (Mr 160,000–220,000) which may be complexed to a smaller polypeptide (Mr 29,000). The structure of the receptor protein suggests that it may be a synapse-specific cell recognition molecule. Intracellularly, the α-latrotoxin receptor interacts with synaptotagmin, a calcium- and phospholipid-binding protein specifically localized in the synaptic vesicle membrane. This interaction may be important for targeting of synaptic vesicles to presynaptic release sites
Influence of N. Gogol’s and M. Saltykov-Shchedrin’s Satire on Michail Bulgakov’s Prose
The article is concerned with the study of literary relationships between the satire of the famous 20th-century Russian writer M. Bulgakov and the works by the Russian classics of the 19th century – N.V. Gogol and M.Y. Saltykov-Shchedrin. The article describes Gogol’s and Saltykov-Shchedrin’s influence on Bulgakov’s satirical poetics, especially in the period of his development as a writer. Special attention is given to the device of grotesque and the motives of mechanicalness and lifelessness, forming the artistic worlds of the writers under study. The authors note that the technical progress and the rapid development of mechanized production in the 20th century, combined with the satirical motive of primitivism, characteristic of Russian literature, left an imprint on the nature of Bulgakov’s grotesque. The writers at issue are united by such common feature of the satirical poetics as turning to fantasy, hyperbole, ‘strange and queer things’. The article shows the way Bulgakov perceived and embodied the principles of Gogol’s and Shchedrin’s world perception through the comic mixing of absurd, ghostly and real. Bulgakov’s way of seeing the world is characterized as ‘delirious reality’. At the same time, Bulgakov, as well as his literary teachers in the sphere of satire, showed oddness and divergence as regularity, while the comicality of fantasy in his works finally turns into the drama of reality
Proton Beam Defocusing as a Result of Self-Modulation in Plasma
The AWAKE experiment will use a \SI{400}{GeV/c} proton beam with a
longitudinal bunch length of to create and sustain
GV/m plasma wakefields over 10 meters . A 12 cm long bunch can only drive
strong wakefields in a plasma with after the self-modulation instability (SMI)
developed and microbunches formed, spaced at the plasma wavelength. The fields
present during SMI focus and defocus the protons in the transverse plane
\cite{SMI}. We show that by inserting two imaging screens downstream the
plasma, we can measure the maximum defocusing angle of the defocused protons
for plasma densities above .
Measuring maximum defocusing angles around 1 mrad indirectly proves that SMI
developed successfully and that GV/m plasma wakefields were created. In this
paper we present numerical studies on how and when the wakefields defocus
protons in plasma, the expected measurement results of the two screen
diagnostics and the physics we can deduce from it.Comment: 3 pages, 2 figures, Conference Proceedings of NAPAC 201
THE ARCHETYPE OF THE FOOL/THE JESTER/THE WHACKY AND ITS ARTISTIC EMBODIMENT IN THE CHARACTERS – “OUTSIDERS” IN SERGEI DOVLATOV’S PROSE
Abstract. The article deals with the fiction by Sergey Dovlatov, the famous Russian-American writer and journalist of the last third of the 20th century. The main aim of the article is to show the influence of the Russian folklore on the formation of the leading type of characters in Dovlatov’s prose. The paper shows that this type, which received in criticism the name of “Dovlatov’s outsiders”, is the realization of the archetype of the fool/the jester/the whacky, widespread in Russian and world folklore, a kind of variation of the fairy-tale “hopeless hero”. On examples ofS. Dovlatov’s story “Pushkin Hills”, his collections of short stories “Ours” and “The Compromise”, the authors study not only the genesis of this type of characters but also their functions in the literary text, the impact on the content of works and readers’ perception. Much attention is attributed to the mechanisms of humor in Dovlatov’s texts. His characters are rebels and outlaws, whackies and jesters at the same time. They cannot “integrate” into the Soviet reality and destabilize it with their clownish behavior. The analysis of his prose shows that S. Dovlatov’s characters, and the humorous world in general, have an emphatically symbolic character. Therefore, the authors of the article, along with the traditional for the study of Dovlatov’s stories historical and genetic approach, involved mythological and structural- semiotic methods that contribute to the consideration of the symbolic nature of humor and its counter-sign function in the literary text.Keywords: Sergei Dovlatov, humor, Russian prose of the 20th century, folklore, archetype, semiosphere, “outsiders”, good sense of humor, whacky, absurd
Reusing Test-Cases on Different Levels of Abstraction in a Model Based Development Tool
Seamless model based development aims to use models during all phases of the
development process of a system. During the development process in a
component-based approach, components of a system are described at qualitatively
differing abstraction levels: during requirements engineering component models
are rather abstract high-level and underspecified, while during implementation
the component models are rather concrete and fully specified in order to enable
code generation. An important issue that arises is assuring that the concrete
models correspond to abstract models. In this paper, we propose a method to
assure that concrete models for system components refine more abstract models
for the same components. In particular we advocate a framework for reusing
testcases at different abstraction levels. Our approach, even if it cannot
completely prove the refinement, can be used to ensure confidence in the
development process. In particular we are targeting the refinement of
requirements which are represented as very abstract models. Besides a formal
model of our approach, we discuss our experiences with the development of an
Adaptive Cruise Control (ACC) system in a model driven development process.
This uses extensions which we implemented for our model-based development tool
and which are briefly presented in this paper.Comment: In Proceedings MBT 2012, arXiv:1202.582
Biopreservation of hepatocytes: current concepts on hypothermic preservation, cryopreservation, and vitrification
Isolated liver cells (primarily isolated hepatocytes) have found important applications in science and medicine over the past 40 years in a wide range of areas, including physiological studies, investigations on liver metabolism, organ preservation and drug de-toxification, experimental and clinical transplantation. An integral component of many of these works is the need to store the isolated cells, either for short or long-term periods. This review covers the biopreservation of liver cells, with a focus on the history of liver cell biopreservation, the application of hypothermia for short-term storage, standard cryopreservation methods for isolated hepatocytes, the biopreservation of other types of liver cells, and recent developments such as vitrification of hepatocytes. By understanding the basis for the different approaches, it will be possible to select the best options for liver cell biopreservation in different applications, and identify ways to improve preservation protocols for the future.Fil: Fuller, Barry J.. University College London; Estados UnidosFil: Petrenko, Alexander Y.. Ukraine Academy of Sciences; UcraniaFil: Rodriguez, Joaquin Valentin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Secretaria de Ciencia y Técnica. Centro Binacional de Investigación en Criobiología Clínica y Aplicada; ArgentinaFil: Somov, Alexander Y.. Ukraine Academy of Sciences; UcraniaFil: Balaban, Cecilia Lucía. Universidad Nacional de Rosario. Secretaria de Ciencia y Técnica. Centro Binacional de Investigación en Criobiología Clínica y Aplicada; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; ArgentinaFil: Guibert, Edgardo Elvio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario; Argentina. Universidad Nacional de Rosario. Secretaria de Ciencia y Técnica. Centro Binacional de Investigación en Criobiología Clínica y Aplicada; Argentin
Rule-based Test Generation with Mind Maps
This paper introduces basic concepts of rule based test generation with mind
maps, and reports experiences learned from industrial application of this
technique in the domain of smart card testing by Giesecke & Devrient GmbH over
the last years. It describes the formalization of test selection criteria used
by our test generator, our test generation architecture and test generation
framework.Comment: In Proceedings MBT 2012, arXiv:1202.582
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