bluuebunny/crossref_metadata_2025 huggingface dataset:
Power spectral density of the heterogeneous fracture compliance from scattered elastic wavefields
Authors: Minato Shohei , Ghose Ranajit
Published: February 2014

Using the scattered elastic wavefield, a method to derive the power spectral density (PSD) of the heterogeneous compliance distribution, along the plane of a single fracture, is formulated. The method involves estimation of the stress field at the fracture depth from the scattered wavefield followed by least-squares optimization of the PSD of the stress field. We consider a 2D geometry and incident plane waves. The derivations are made in the frequency-wavenumber domain. To derive the relationship between the scattered wavefield and the PSD of the heterogeneous compliance, perturbation theory is used. In the forward modeling, the scattering response of the heterogeneous compliance is estimated, assuming a stationary random process. Numerical tests of the proposed method of PSD estimation offer important insights. The estimated PSD of the compliance (given by the standard deviation [Formula: see text] and the correlation length [Formula: see text], assuming a Gaussian distribution) as a statistical measure of the heterogeneous fracture compliance is robust against fracture depth uncertainties. Furthermore, the sparse spatial sampling of the wavefield is not problematic as long as the data contain those wavenumber components which represent the slope of the PSD of the stress field. However, when the sampling interval is too large compared to the correlation length of the heterogeneous compliance distribution, it is difficult to estimate accurately the PSD of the compliance due to spatial aliasing and small amplitude variation within the available wavenumber. For a given spatial sampling, the use of higher frequencies results in a stronger amplitude variation in the scattered wavefield. This leads to better estimates of the PSD of the compliance via a least-squares optimization. In the presence of white noise, a change in the PSD of the stress field at the fracture depth significantly affects the PSD estimates. In this case, a data-driven amplitude correction improves the estimates of [Formula: see text] and [Formula: see text].
Closing the performance gap between an iterative frequency-domain solver and an explicit time-domain scheme for 3D migration on parallel architectures
Authors: Knibbe H. , Mulder W. A. , Oosterlee C. W. , Vuik C.
Published: February 2014

Three-dimensional reverse-time migration with the constant-density acoustic wave equation requires an efficient numerical scheme for the computation of wavefields. An explicit finite-difference scheme in the time domain is a common choice. However, it requires a significant amount of disk space for the imaging condition. The frequency-domain approach simplifies the correlation of the source and receiver wavefields, but requires the solution of a large sparse linear system of equations. For the latter, we use an iterative Krylov solver based on a shifted Laplace multigrid preconditioner with matrix-dependent prolongation. The question is whether migration in the frequency domain can compete with a time-domain implementation when both are performed on a parallel architecture. Both methods are naturally parallel over shots, but the frequency-domain method is also parallel over frequencies. If we have a sufficiently large number of compute nodes, we can compute the result for each frequency in parallel and the required time is dominated by the number of iterations for the highest frequency. As a parallel architecture, we consider a commodity hardware cluster that consists of multicore central processing units (CPUs), each of them connected to two graphics processing units (GPUs). Here, GPUs are used as accelerators and not as an independent compute node. The parallel implementation of the 3D migration in frequency domain is compared to a time-domain implementation. We optimize the throughput of the latter with dynamic load balancing, asynchronous I/O, and compression of snapshots. Because the frequency-domain solver uses matrix-dependent prolongation, the coarse-grid operators require more storage than available on GPUs for problems of realistic size. Due to data transfer, there is no significant speedup using GPU-accelerators. Therefore, we consider an implementation on CPUs only. Nevertheless, with the parallelization over shots and frequencies, this approach could compete with the time-domain implementation on multiple GPUs.
Time-lapse walkaway vertical seismic profile monitoring for CO2 injection at the SACROC enhanced oil recovery field: A case study
Authors: Yang Di , Malcolm Alison , Fehler Michael , Huang Lianjie
Published: February 2014

Geologic carbon storage involves large-scale injections of carbon dioxide into underground geologic formations. Changes in reservoir properties resulting from [Formula: see text] injection and migration can be characterized using monitoring methods with time-lapse seismic data. To achieve economical monitoring, vertical seismic profile (VSP) data are often acquired to survey the local injection area. We investigated the capability of walkaway VSP monitoring for [Formula: see text] injection into an enhanced oil recovery field at SACROC, West Texas. VSP data sets were acquired in 2008 and 2009, and [Formula: see text] injection took place after the first data acquisition. Because the receivers were located above the injection zone, only reflection data contain the information from the reservoir. Qualitative comparison between reverse-time migration images at different times revealed vertical shifts of the reflectors’ center, indicating the presence of velocity changes. We examined two methods to quantify the changes in velocity: standard full-waveform inversion (FWI) and image-domain wavefield tomography (IDWT). FWI directly inverts seismic waveforms for velocity models. IDWT inverts for the time-lapse velocity changes by matching the baseline and time-lapse migration images. We found that, for the constrained geometry of VSP surveys, the IDWT result was significantly more consistent with a localized change in velocity as expected from a few months of [Formula: see text] injection. A synthetic example was used to verify the result from the field data. By contrast, FWI failed to provide quantitative information about the volumetric velocity changes because of the survey geometry and data frequency content.
Ultrasonic leaky flexural waves in multilayered media: Cement bond detection for cased wellbores
Authors: He Xiao , Chen Hao , Wang Xiuming
Published: February 2014

Good cement bond quality is significant for an oil well to prevent hydraulic communication between zones and to ensure layered exploitation. Conventional sonic logging techniques are limited to the detection region immediately behind the casing, so they can hardly be used to interpret the bonding quality between cement and rock formations. To develop a cementing evaluation method for the whole annulus, ultrasonic leaky flexural modes in radially multilayered media were investigated through finite-difference modeling. The guided waves were excited and received by pitch-catch transducers arranged in the borehole. According to the numerical results, two kinds of flexural modes were sensitive to cement debonding at different interfaces, respectively. For the primary flexural waves that arrived early and propagated all along the casing, the attenuation levels decreased due to the appearance of a fluid-filled channel between the casing and the cement sheath. The acoustic signals arriving later were the secondary flexural modes contributed by reflection echoes from the formation. They will be greatly strengthened once a debonding defect appears at the cement-formation boundary, and the arrival time of secondary flexural waves can also be applied to predict the thickness of the cement sheath. Consequently, it is possible to propose an integrated evaluation for both interfaces of the cement annulus by extracting properties of the primary and secondary flexural waves.
Spaces of Desire: Consumer Bound and Unbound
Authors: Ditchev Ivaylo
Published: February 2014

This essay explores the relation between space—real and imaginary— and consumerist desire. Any process of modernization implies, on the one hand, social and geographical mobility that makes it possible for the individual to opt to change his or her condition and, on the other hand, a growing transparency of the world, where life of faraway people fascinates and attracts. Such a spatial disposition, where the object of desire always slips away into a different space, at the same time accessible and out of reach for now, supplies the fuel for the capitalist machine. It seems that such a disposition would be irrelevant in the case of socialism, known for its ideology of productivism and its practice of consumer shortage. I will argue that, in fact, Soviet-style societies were based on a similar logic, even if the “elsewheres” generating desire were castigated by propaganda and considered temporary phenomena by socioeconomic science. In fact, the explosion of consumerism after the fall of the Berlin Wall might show that the strategies of seduction under what we could call state capitalism were even more radical. Desire suddenly unbound could also account for the disappearance of critical thinking in Eastern Europe during the first decade of transition.
Postcolonial Media Studies in Postsocialist Europe
Authors: Imre Anikó
Published: February 2014

I argue that postcolonial discourses are essential to unearthing and revising the complicated dynamic of codependence between Western and Eastern European nationalisms, which is haunted by internalized and rarely acknowledged traces of imperialism on both sides. However, the spatial expansion of postcolonial discourse to Europe’s own backyard needs to be matched by an expansion of research methods and objects. Postcolonial studies’ traditional commitment to theory and to textual analysis of literature and art cinema is beneficially complemented by engaging with popular media, such as television. It is also crucial to critically analyze the contexts of production and dissemination in which certain aesthetic and theoretical models are formed, lest we risk simply reaffirming the patterns in which Eastern European cultural nationalisms have reproduced themselves, which have also functioned to contain and disavow racism and imperialism. I propose to integrate within the postcolonial sphere methods and approaches from anthropology, sociology, cultural studies, and media and communication studies, which have produced a significant body of work on everyday socialist and postsocialist practices but have remained under the radar of elite national cultures. They have also stayed in fairly isolated disciplinary brackets and thus badly need postcolonial studies’ sophisticated theorizing of ideology and identity and its commitment to historiography. At the end, I outline three sample possibilities for such a geopolitically expanded, methodologically hybridized encounter: the postcolonial study of popular (post)socialist television; a postcolonial take on the European circulation of socialist film cultures; and contemporary reality television focused on the European underclass.
Post-Soviet Russia: The Land of the Oil Curse, Pussy Riot, and Magical Historicism
Authors: Etkind Alexander
Published: February 2014

The early twenty-first-century Russia still calls itself, and is called, “post-Soviet.” But this term increasingly sounds like a purposeful euphemism, which both insiders and observers from outside are using to conceal the novelty of Putinism. Though Putinism is entirely different from Stalinism, post-Soviet Russia still defines itself in contrast to its Soviet past, with all the ambiguity that the prefix post entails. Looking at a number of cultural texts that explicitly address the issues of memory, mourning, and atonement, this essay expands this argument by connecting it to Russia’s political economy. The oil curse is a self-imposed condition, a contingent political process that depends on unique choices of authorities and the population. The oil curse does not determine Russia’s arrested development; it only provides conditions that are eagerly used by the group in power. For Russia’s hyperextractive state, the population is superfluous. Introducing the concept of magical historicism, the essay aims at an intrinsic analysis of cultural change. It uses fictional texts, such as Dmitry Bykov’s and Vladimir Sorokin’s recent novels, to explore political, gender, and cultural results of synergy between the oil and gas trade and security services. This hyperextractive synergy creates an overmasculine, cynical, and misogynistic culture—petromachismo, as I prefer to call it.
Perverse Tongues, Postsocialist Translations
Authors: Starosta Anita
Published: February 2014

Challenging the prevailing use of the term postsocialism as merely another designation for former Second World spaces, “Perverse Tongues, Postsocialist Translations” works toward articulating it instead as a critical and analytical lens on the current global condition. The “postsocialist” here marks modes of personhood and locution that are perverse with respect to the reproductive aims of the post-1989 order. Deriving from the socialist past but not reducible either to its official doctrines or to its official dissident cultures, these modes persist in the present and disable, however momentarily, the apparently closed language of neoliberal freedom and progress. The essay turns to figurations of Eastern Europe’s contemporary predicament found in Michał Witkowski’s novel Lovetown (2004), which tracks an aging queer community for whom the transition to capitalism and liberal democracy brought not emancipation but the threat of catastrophe; and in Szabolcs Hajdu’s magical-realist film Bibliothèque Pascal (2010), which tells the story of a woman who returns from working in an elite brothel in the UK. What makes these texts apt reflections on the effects of the neoliberal order and indices of a more general global condition is not merely the social and economic marginality of these subjects. As they resist both the liberal dream of common humanity that might be achieved through recognition and the neoliberal dream of prosperity that is indifferent to the human as such, the novel and the film call for practices of reading and spectatorship that would be attentive to subjective and temporal fractures within the putatively unified global present.
From Twelve Circles
Authors: Andrukhovych Yuri
Published: February 2014

In this excerpt from the novel Twelve Circles, photographer Karl-Joseph Zumbrunnen takes leave of his earthly body and experiences an unexpected lightness of being. It is just before dawn on Easter Sunday, but he does not turn toward the resurrection of the rising sun; he sets instead on a westward flight, away from the Ukrainian town where he was killed, toward Vienna. His journey will follow the contour of the oval formed by the Carpathian Mountains, the center of Europe, according to the text, and take him from Transylvania, along the Danube, to a light-filled crowded stadium to which he is admitted after having answered a ritual question. The topography of his itinerary is matched by the topology of his memory, as he sees a forlorn lover working on the 112th page of a draft letter, various lovers sleeping in each other’s arms, and the train stations that were to be the subject of his next project. When his astral body is absorbed by the light of the stadium, the author takes leave of his readers, but not before knocking on wood.
Eastern Europe, Art, and the Politics of Representation
Authors: Erjavec Aleš
Published: February 2014

This article focuses on some of the ways in which subjectivization, representation, and self-representation have been carried out in Eastern Europe and on the role that art plays in these processes. The author first points to two related features of the region: an absence of a common point of identification and a split between the view from the outside and that from within the region. Although it appears that Eastern Europe has existed as a self-reflected regional identity, it existed as such only at the time of the Cold War; otherwise, a self-reflected identity existed only in its constitutive (national) parts. Rancière’s notions of “voice” and “speech” are introduced, with “speech” being proposed as a precondition for subjectivization and political representation. Various analytic approaches in the study of Eastern Europe and its history are then explored, leading to the conclusion that the frequent application of postcolonial theories to the study of the region is to some extent enlightening but essentially insufficient. The author then broaches the main topic of the article—the import of Eastern European art in recent processes of subjectivization, identification, and representation of the region’s constitutive parts. These started in the 1980s and reached their apogee in the decade after 1989, when art acquired a central place and an unprecedented role in Eastern European societies, for it not only expressed and reflected upon the ongoing political and social events but also supplied persuasive artistic achievements that facilitated Eastern Europe’s progressive proximity to Western Europe. This special position of art in the region diminished with the historical developments that followed, which no longer necessitated or supported such an extraordinary place of art in the former East Europe.
Management style as a system of economic and socio-cultural cooperation in the organization
Authors: Трошихин Владимир , Troshikhin Vladimir
Published: February 2014

The article discloses the content and essence of management

style as an integral criterion of economic and socio-cultural

cooperation, sub stantiates the methodology of its study and formation

and shows the role and importance of the command style of

subordination in the improvement of the efficiency of management

and creative cooperation in the organization.
Trust: effective transition from the command-administrative relations to collaboration
Authors: Кондратьев Эдуард , Kondratev Eduard
Published: February 2014

This article presents the “Trust” as a micro-level institution.

The article shows how to use the “Credibility” provided the

institutional transition from a Command-Administrative Relations

— characteristic of mass production to the cooperative relationship,

which is the base of Lean Manufacturing. It is proved that

a relationship of trust has a positive influence on the development

of management personnel. The “subjectivity” of the latter is supporting

institutional change and provides it with the enterprise longterm

dynamic development.
Modern management of the educational process
Authors: Черкасов Михаил , Cherkasov Mikhail
Published: February 2014

The article analyzes the features and applications of modern

teaching methods to improve the quality of education of Russian

students. Disclosed prospects of each innovative forms of learning

in the educational process.
Economic Development Sustainability of Russia’s Territories
Authors: Басовский  , Basovskiy Leonid , Басовская  , Basovskaya Elena
Published: February 2014

Technique for assessment of economic development sustainability of Russia’s

regions is provided. Methodologically the technique is based on diagnosing the

loss of sustainability in economic growth and assessing the degree of instability.

The authors propose to assess the degree of sustainability by such measure, as

variance in the economy’s growth rate, while the risks of instable growth — by

an index, reflecting relative variance in economic growth rates.

Economic growth sustainability and dynamics for several RF administrative

territories are assessed, including Belgorod oblast, Bryansk oblast, Volgograd

oblast, Pskov oblast, the cities of Moscow and St. Petersburg, the Republic of

Dagestan and Krasnodar krai. The estimates are based on statistics for the

2000—2011 years period.

As is found out, different territories has different periods of sustainable and

unsustainable development as well as different degrees of economic growth

instability. In terms of economic development Belgorod oblast, the city of St.

Petersburg, Krasnodar krai and the Republic of Dagestan are stable as compared

to the growth of the overall Russian economy. Such territories, as Bryansk

oblast, Volgograd oblast, Pskov oblast and the city of Moscow show instability

of economic development as compared to the Russian economy as a whole. As

correlation and regression analysis shows, indices of economic development

instability significantly affect investments in the regional economy.

Based on a small sample of administrative territories the authors show that

instability of economic development is responsible for 40 per cent reduction in

investments. Thus the conclusion is made that economic development

instability is a rather significant factor of the territory’s investment climate.
The Property Insurance System in The Russian Empire, in the Latter Half of the 19th to the Early 20th Century
Authors: Краюшкина  , Krayushkina Elena
Published: February 2014

The system of property insurance in the pre-October-revolution Russia is explored. Typology of insurance institutions and types of insurance are proposed. Insurance legislation in the Russian Empire is reviewed and dynamics in the development of different types of insurance are assessed.
Approaches to formation of system of planning of government procurements at limited production capabilities of the supplier
Authors: Логвинов  , Logvinov Syergyey , Логвинов  , Logvinov Syergyey
Published: February 2014

Methodical approaches to optimal placement of government contract are

considered for a situation of a few or even one supplier. The techniques of

optimum planning, which takes into account the interests of both the

government customer and the supplier are applied. The authors substantiate

contract terms and parameters by applying tools of linear programming and

compromise criterion as well as theory of games criteria.
The Issue оf University Graduate’s Competitiveness: Regional Practice
Authors: Медушевская  , Medushevskaya Inna
Published: February 2014

The meaning of «university graduate» concept within the system of economic

relations is specified; the essence of graduates’ competitiveness is revealed as

well as its place in the system of interrelated economic categories; issues and

challenges with which graduates encounter at the regional labor markets are

outlined.

By questioning graduates and employers of the Penza region, the author determines

competitive advantages of the formers in terms of assessing various

subjects of market relations. Ways to enhance university graduates’ competitiveness

at local labor markets are proposed and practical guidelines are elaborated.
Fair Market Value оf а Business аs а Factor оf Its Investment Attractiveness
Authors: Сергеева  , Sergeeva Anna
Published: February 2014

Crucial importance of a business entity’s market value for its investment

attractiveness is proved. Factors determining market value of a business entity

and its attractiveness for investments are summarized. The main points of

concept of value-based management and its impact on investment attractiveness

are highlighted. In particular, the nature and contents of entity re-structuring

process as an integral phase of value delivery are briefly considered, restructuring

goals of national business entities are outlined from the standpoint

of larger national and foreign companies operating in this country. Approaches

and techniques of business valuation, proposed by Jay Fishman , Shannon

Pratt, Clifford Griffith, Keith Wilson, as well as terms for use of each. Special

attention is given to value added as an economic measure and contributor to

both the investment value dynamics and business value. It is concluded that

value-based management has to include the development of remuneration

mechanism closely tied to changes in the value and investment attractiveness

of a business entity.
Terminator management, or The art of destruction by competent individuals
Authors: Комаров Евгений , Komarov Evgeniy
Published: February 2014

Most publications in management can be described as

«energetic» presenting orientation to certain ideals, that even hardcore

optimists believes that will never come true. So it is best to

refer to actual practice and see what stirs people to operate normally.

This original article describes the essence of terminator management,

which in practice is, first of all, as the art of destruction of

competent employees.
WHAT IS NEW IN ASTROPARTICLE PHYSICS
Authors: Giovannelli Franco
Published: February 2014

In this brief review paper I will point to the most important steps that have been made in recent decades toward a better understanding of the physics governing our Universe. Because of the limited length of this paper, I have selected only a few results that, in my opinion, have been of crucial importance.
THE FIRST CENTURY OF COSMIC RAYS, AN HISTORICAL OVERVIEW
Authors: Jones Lawrence W.
Published: February 2014

The 1912 balloon flights of Victor Hess and related activities in those years are reviewed. Subsequent research during the early 20th Century is noted, including the discovery of the positron, mesons, and air showers. The cosmic ray–accelerator interrelations are noted, including cosmic ray studies at Echo Lake and Mt. Evans, Colorado (USA). The more recent evolution of cosmic ray research programs to astrophysical and cosmological studies, and the major programs such as Auger and AMS conclude this discussion of the century of cosmic ray research.
OUR GALACTIC CENTER – THE NEAREST BURNING DISK
Authors: Kundt Wolfgang
Published: February 2014

This short presentation will update my more than 25 years long attempts at understanding
the actions of the Central Engine at our Galactic Center.
SEARCH FOR DARK MATTER WITH GAMMA-RAYS: A REVIEW
Authors: Morselli Aldo
Published: February 2014

Successfully launched in June 2008, the Fermi Gamma-ray Space Telescope, formerly named GLAST, has been observing the high-energy gamma-ray sky with unprecedented sensitivity in
the 20MeV ÷ 300 GeV energy range and electrons + positrons in the 7 GeV ÷ 1TeV range, opening a new observational window on a wide variety of astrophysical objects.
THE FIRST STARS
Authors: Whalen Daniel J.
Published: February 2014

Pop III stars are the key to the character of primeval galaxies, the first heavy elements, the onset of cosmological reionization, and the seeds of supermassive black holes. Unfortunately, in spite of their increasing sophistication, numerical models of Pop III star formation cannot yet predict the masses of the first stars. Because they also lie at the edge of the observable universe, individual Pop III stars will remain beyond the reach of observatories for decades to come, and so their properties are unknown. However, it will soon be possible to constrain their masses by direct detection of their supernovae, and by reconciling their nucleosynthetic yields to the chemical abundances measured in ancient metal-poor stars in the Galactic halo, some of which may bear the ashes of the first stars. Here, I review the state of the art in numerical simulations of primordial stars and attempts to directly and indirectly constrain their properties.
DAMA RESULTS: DARK MATTER IN THE GALACTIC HALO
Authors: Bernabei R. , Belli P. , Cappella F. , Caracciolo V. , Cerulli R. , Dai C. J. , D’Angelo A. , Di Marco A. , He H. L. , Incicchitti A. , Ma X. H. , Montecchia F. , Sheng X. D. , Wang R. G. , Ye Z. P.
Published: February 2014

Experimental efforts and theoretical developmens support that most of the Universe is Dark and a large fraction of it should be made of relic particles; many possibilities are open on their nature and interaction types. In particular, the DAMA/LIBRA experiment at Gran Sasso Laboratory (sensitive mass: ~250 kg) is mainly devoted to the investigation of Dark Matter (DM) particles in the Galactic halo by exploiting the model independent DM annual modulation signature with higly radiopure Na I(Tl) targets. DAMA/LIBRA is the succesor of the first generation DAMA/NaI (sensitive mass: ~100 kg); cumulatively the two experiments have released so far the results obtained by analyzing an exposure of 1.17 t yr, collected over 13 annual cycles. The data show a model independent evidence of the presence of DM particles in the galactic halo at 8.9σ confidence level (C.L.). Some of the already achieved results are shortly reminded, the last upgrade occurred at fall 2010 is mentioned and future perspectives are sumarized.
NON-THERMAL EMISSION FROM CATACLYSMIC VARIABLES: IMPLICATIONS ON ASTROPARTICLE PHYSICS
Authors: Šimon Vojtech
Published: February 2014

We review the lines of evidence that some cataclysmic variables (CVs) are the sources of non-thermal radiation. It was really observed in some dwarf novae in outburst, a novalike CV in the high state, an intermediate polar, polars, and classical novae (CNe) during outburst. The detection of this radiation suggests the presence of highly energetic particles in these CVs. The conditions for the observability of this emission depend on the state of activity, and the system parameters. We review the processes and conditions that lead to the production of this radiation in various spectral bands, from gamma-rays including TeV emission to radio. Synchrotron and cyclotron emissions suggest the presence of strong magnetic fields in CV. In some CVs, e.g. during some dwarf nova outbursts, the magnetic field generated in the accretion disk leads to the synchrotron jets radiating in radio. The propeller effect or a shock in the case of the magnetized white dwarf (WD) can lead to a strong acceleration of the particles that produce gamma-ray emission via pi0 decay; even Cherenkov radiation is possible. In addition, a gamma-ray production via pi0 decay was observed in the ejecta of an outburst of a symbiotic CN. Nuclear reactions during thermonuclear runaway in the outer layer of the WD undergoing CN outburst lead to the production of radioactive isotopes; their decay is the source of gamma-ray emission. The production of accelerated particles in CVs often has episodic character with a very small duty cycle; this makes their detection and establishing the relation of the behavior in various bands difficult.
ASTRONOMICAL PLATE ARCHIVES AND SUPERMASSIVE BLACK HOLE BINARIES
Authors: Hudec René
Published: February 2014

The recent extensive digitisation of astronomical photographic plate archives, the development of new dedicated software and the use of powerful computers have for the first time enabled effective data mining in extensive plate databases, with wide applications in various fields of recent astrophysics. As an example, analyses of supermassive binary black holes (binary blazars) require very long time intervals (50 years and more), which cannot be provided by other data sources. Examples of data obtained from data mining in plate archives are presented and briefly discussed.
XMM-NEWTON SCIENTIFIC HIGHLIGHTS: X-RAY SPECTROSCOPIC POPULATION STUDIES OF AGN
Authors: Guainazzi Matteo
Published: February 2014

In this paper I review the contribution that the XMM-Newton ESA X-ray mission has given to our understanding of Active Galactic Nuclei, together with other operational, and complementary, X-ray facilities. I will focus on answering three basic questions: a) to which extent do AGN share the same engine?; b) to which extent are AGN “relativistic machines”?; c) to which extent do AGN affect their immediate environment?
TeV GAMMA RAYS: OBSERVATIONS VERSUS EXPECTATIONS & THEORY
Authors: Krennrich Frank
Published: February 2014

The scope of this paper is to discuss two important questions relevant for TeV γ-ray astronomy; the pursuit to reveal the origin of cosmic rays in our galaxy, and the opacity of the universe in γ-rays. The origin of cosmic rays stipulated the field of TeV astronomy in the first place, and led to the development of the atmospheric Cherenkov technique; significant progress has been made in the last decade through the detection of several supernova remnants, the primary suspects for harboring the acceleration sites of cosmic rays. TeV γ-rays propagate mostly unhindered through the galactic plane, making them excellent probes of processes in SNRs and other galactic sources. Key results related to the SNR origin of cosmic rays are discussed. TeV γ-ray spectra from extragalactic sources experience significant absorption when traversing cosmological distances. The opacity of the universe to γ-rays above 10 GeV progressively increases with energy and redshift; the reason lies in their pair production with ambient soft photons from the extragalactic background light (EBL). While this limits the γ-ray horizon, it offers the opportunity to gain information about cosmology, i.e. the EBL intensity, physical conditions in intergalactic space, and potentially new interaction processes. Results and implications pertaining to the EBL are given.
AGILE DATA CENTER AT ASDC AND AGILE HIGHLIGHTS
Authors: Pittori Carlotta
Published: February 2014

We present an overview of the main AGILE Data Center activities and the AGILE scientific highlights during the first 5 years of operations. AGILE is an ASI space mission in joint collaboration with INAF, INFN and CIFS, dedicated to the observation of the gamma-ray Universe. The AGILE satellite was launched on April 23rd, 2007, and is devoted to gamma-ray astrophysics in the 30MeV ÷ 50 GeV energy range, with simultaneous X-ray imaging capability in the 18 ÷ 60 keV band. Despite the small size and budget, AGILE has produced several important scientific results, including the unexpected discovery of strong and rapid gamma-ray flares from the Crab Nebula over daily timescales. This discovery won AGILE PI and the AGILE Team the prestigious Bruno Rossi Prize for 2012, an international award in the field of high energy astrophysics. Thanks to its sky monitoring capability and fast ground segment alert system, AGILE is substantially improving our knowledge of the gamma-ray sky, also making a crucial contribution to the study of the terrestrial gamma-ray flashes (TGFs) detected in the Earth atmosphere. The AGILE Data Center, part of the ASI Science Data Center (ASDC) located in Frascati, Italy, is in charge of all the science oriented activities related to the analysis, archiving and distribution of AGILE data.
MEASURING SUPERMASSIVE BLACK HOLE SPINS IN AGN
Authors: Brenneman Laura
Published: February 2014

Measuring the spins of supermassive black holes (SMBHs) in active galactic nuclei (AGN) can inform us about the relative role of gas accretion vs. mergers in recent epochs of the life of the host galaxy and its AGN. Recent theoretical and observation advances have enabled spin measurements for ten SMBHs thus far, but this science is still very much in its infancy. Herein, I discuss how we measure black hole spin in AGN, using recent results from a long Suzaku campaign on NGC 3783 to illustrate this process and its caveats. I then present our current knowledge of the distribution of SMBH spins in the local universe. I also address prospects for improving the accuracy, precision and quantity of these spin constraints in the next decade and beyond with instruments such as NuSTAR, Astro-H and future large-area X-ray telescopes.
QUANTIFICATION OF RESPIRATORY SINUS ARRHYTHMIA WITH HIGH-FRAMERATE ELECTRICAL IMPEDANCE TOMOGRAPHY
Authors: Antink Christoph Hoog , Leonhardt Steffen
Published: February 2014

Respiratory Sinus Arrhythmia, the variation in the heart rate synchronized with the breathing cycle, forms an interconnection between cardiac-related and respiratory-related signals. It can be used by itself for diagnostic purposes, or by exploiting the redundancies it creates, for example by extracting respiratory rate from an electrocardiogram (ECG). To perform quantitative analysis and patient specific modeling, however, simultaneous information about ventilation as well as cardiac activity needs to be recorded and analyzed. The recent advent of medically approved Electrical Impedance Tomography (EIT) devices capable of recording up to 50 frames per second facilitates the application of this technology. This paper presents the automated selection of a cardiac-related signal from EIT data and quantitative analysis of this signal. It is demonstrated that beat-to-beat intervals can be extracted with a median absolute error below 20 ms. A comparison between ECG and EIT data shows a variation in peak delay time that requires further analysis. Finally, the known coupling of heart rate variability and tidal volume can be shown and quantified using global impedance as a surrogate for tidal volume.
A NOVEL BCG SENSOR-ARRAY FOR UNOBTRUSIVE CARDIAC MONITORING
Authors: Böhm Anna , Brüser Christoph , Leonhardt Steffen Leonhardt
Published: February 2014

Unobtrusive heart rate monitoring is a popular research topic in biomedical engineering. The reason is that convential methods, e.g. the clinical gold standard electrocardiography, require conductive contact to the human body. Other methods such as ballistocardiography try to record these vital signs without electrodes that are attached to the body. So far, these systems cannot replace routine procedures. Most systems have some drawbacks that cannot be compensated, such as aging of the sensor materials or movement artifacts. In addition, the signal form differs greatly from an ECG, which is an electrical signal. The ballistocardiogram has a mechanical source, which makes it harder to evaluate. We have developed a new sensor array made of near-IR-LEDs to record BCGs. IR-sensors do not age in relevant time scales. Analog filtering was neccesary, because the signal amplitude was very small. The digitized data was then processed by various algorithms to extract beat-to-beat or breath-to-breath intervals. The redundancy of multiple BCG channels was used to provide a robust estimation of beat-to-beat intervals and heart rate. We installed the system beneath a mattress topper of a hospital bed, but any other bed would have been sufficient. The validation of this measurement system shows that it is well suited for BCG recordings. The use of multiple channels has proven to be superior to relying on a single BCG channel.
ANALYSIS OF THE ACCURACY OF FIBRE-OPTIC STRAIN GAUGES
Authors: Jiroutová Dita , Vokáč Miroslav
Published: February 2014

In recent years, the field of structure monitoring has been making increasing use of systems based on fiber-optic technologies. Fiber-optic technology offers many advantages, including higher quality measurements, greater reliability, easier installation and maintenance, insensitivity to the environment (mainly to the electromagnetic field), corrosion resistance, safety in explosive and flammable environments, the possibility of long-term monitoring and lower cost per lifetime. We have used SOFO fibre-optic strain gauges to perform measurements to check the overall relative deformation of a real reinforced concrete structure. Long-term monitoring of the structure revealed that the measurement readings obtained from these fibre-optic strain gauges differed from each other. Greater attention was therefore paid to the calibration of the fibre-optic strain gauges, and to determining their measurement accuracy. The experimental results show that it is necessary to calibrate SOFO strain gauges before they are used, and to determine their calibration constant.
CONTROL OF THE DOUBLE INVERTED PENDULUM ON A CART USING THE NATURAL MOTION
Authors: Neusser Zdenek , Valášek Michael
Published: February 2014

This paper deals with controlling the swing-up motion of the double pendulum on a cart using a novel control. The system control is based on finding a feasible trajectory connecting the equilibrium positions from which the eigenfrequencies of the system are determined. Then the system is controlled during the motion between the equilibrium positions by the special harmonic excitation at the system resonances. Around the two equilibrium positions, the trajectory is stabilized by the nonlinear quadratic regulator NQR (also known as SDRE – the State Dependent Riccati Equation). These together form the control between the equilibrium positions demonstrated on the double pendulum on a cart.
EFFECT OF SLIP VELOCITY ON THE PERFORMANCE OF A SHORT BEARING LUBRICATED WITH A MAGNETIC FLUID
Authors: Patel Rachana U. , Deheri G. M.
Published: February 2014

This paper aims at analyzing the effect of velocity slip on the behavior of a magnetic fluid based infinitely short hydrodynamic slider bearing. Solving the Reynolds’ equation, the expression for pressure distribution is obtained. In turn, this leads to the calculation of the load carrying capacity. Further, the friction is also computed. It is observed that the magnetization paves the way for an overall improved performance of the bearing system. However the magnetic fluid lubricant fails to alter the friction. It is established that the slip parameter needs to be kept at minimum to achieve better performance of the bearing system, although the effect of the slip parameter on the load carrying capacity is in most situations, negligible. It is found that for large values of the aspect ratio, the effect of slip is increasingly significant. Of course, the aspect ratio plays a crucial role in this improved performance. Lastly, it is established that the bearing can support a load even in the absence of flow, which does not happen in the case of a conventional lubricant.
CFD SIMULATION OF A STIRRED DISHED BOTTOM VESSEL
Authors: Vlček Petr , Skočilas Jan , Jirout Tomáš
Published: February 2014

This paper deals with simulation of the fluid flow in a stirred curved-bottom vessel equipped with three curved blade impellers. The power number and the impeller flow rate number are dimensionless characteristics of the system determined from simulation results and compared with relevant experimental data or data from the literature. The model of the system was created in the conventional Gambit and Fluent program. The system is solved for two designs — for an unbaffled vessel, and for a baffled vessel.The vessel is filled with water and the impeller speed            is 100 min−1. Three turbulent models were used for the solution: k-ε, k-ω and RSM. The results were compared with experimental data or data from the literature. The k-ε model had the smallest demands on processor time, and the results compared satisfactorily with the experimental data. The model provides comprehensive information about the characteristics of the system.
HYBRID SHEARWALL SYSTEM — SHEAR STRENGTH AT THE INTERFACE CONNECTION
Authors: Wirth Ulrich , Shirali Nuri , Křístek Vladimír , Kurth Helmut
Published: February 2014

Based on a series of alternating, displacement-controlled load tests on ten one-third scale models, to study the behaviour of the interface of a hybrid shear wall system, it was proved that the concept of hybrid construction in earthquake prone regions is feasible. The hybrid shear-wall system consists of typical reinforced concrete shear walls with composite edge members or flanges. Ten different anchorage bar arrangements were developed and tested to evaluate the column-shearwall interface behaviour under cyclic shear forces acting along the interface between column and wall panel. Finite element models of the test specimens were developed that were capable of capturing the integrated concrete and reinforcing steel behaviour in the wall panels. Special models were  developed to capture the interface behaviour between the edge columns and the shear wall. A comparison between the experimental results and the numerical results shows excellent agreement, and clearly supports the validity of the model developed for predicting the non-linear response of the hybrid wall system under various load conditions.
Frühchristliche Religion als Wahrnehmungsobjekt und Erkenntnisprozess
Authors: Tilly Michael
Published: February 2014

This essay explores the exegetical possibilities and boundaries of the history of religions approach to the New Testament. In part 1 it offers an overview of the history of historical critical exegesis of the New Testament from the magisterial research of the history of religions school to the newest approaches of historical Jesus research. In part 2, three hermeneutical problems for the exegete are outlined: the relationship between text and tradition, the relationship between early Christian literature and its surroundings and the relationship between the New Testament as an ancient collection and its reception today.
„Ich tue mir nichts an, ich gönne mir etwas“ Fastenzeit als spätmoderne geistliche Übung
Authors: Koll Julia
Published: February 2014

Der Artikel beschreibt und erläutert die Wiederentdeckung der Fastenpraxis und markiert fünf unterschiedliche Erfahrungsmomente, die sich mit dem Fasten verbinden.
Spontaneous intestinal perforation and multiple thrombotic events in a neonate with thrombophilia
Authors: Levin Carina , Peniakov Marina , Felszer Clari , Reich Dan , Trougouboff Philippe , Koren Ariel
Published: February 2014

Spontaneous intestinal perforation (SIP), a rare complication in neonates, was diagnosed in a preterm newborn. After surgery, small bowel histology showed acute ischemic changes and one area of perforation. Fibrin thrombus in the submucosal capillary vessels suggested a thrombotic mechanism in the pathogenesis. Subsequently, two severe asynchronous thrombotic events developed: cerebral sinovenous thrombosis and renal vein and inferior vena cava thrombosis. The neonate presented with hypercoagulability and factor V Leiden heterozygosity. This is the first association of SIP with inherited thrombophilia and thrombotic events in a neonate, suggesting hypercoagulability as a new research focus for pathogenesis of this enigmatic disease.
On *-centralizing mappings in rings with involution
Authors: Ali Shakir , Dar Nadeem Ahmed
Published: February 2014

A classical result of Posner states that the existence of a nonzero centralizing derivation on a prime ring forces the ring to be commutative. The main purpose of this paper is to prove a *-version of Posner's theorem mentioned above. Moreover, we describe the structure of an arbitrary additive mapping which is *-centralizing on a prime ring with involution.
Design of a Protection Thermal Energy Storage Using Phase Change Material Coupled to a Solar Receiver
Authors: Verdier D. , Falcoz Q. , Ferrière A.
Published: February 2014

Thermal Energy Storage (TES) is the key for a stable electricity production in future Concentrated Solar Power (CSP) plants. This work presents a study on the thermal protection of the central receiver of CSP plant using a tower which is subject to considerable thermal stresses in case of cloudy events. The very high temperatures, 800 °C at design point, impose the use of special materials which are able to resist at high temperature and high mechanical constraints and high level of concentrated solar flux. In this paper we investigate a TES coupling a metallic matrix drilled with tubes of Phase Change Material (PCM) in order to store a large amount of thermal energy and release it in a short time. A numerical model is developed to optimize the arrangement of tubes into the TES. Then a methodology is given, based from the need in terms of thermal capacity, in order to help the choice of the geometry.