bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature dynamics in decaying isotropic turbulence with Joule heat production
Authors: De Marinis Dario , Chibbaro Sergio , Meldi Marcello , Sagaut Pierre
Published: April 2013

This paper presents an extension of existing works dealing with the dynamics of a passive scalar in freely decaying isotropic turbulence, by accounting for a production mechanism of the passive scalar itself. The physically relevant case of the temperature dynamics in the presence of Joule heating via the dissipation of the turbulent kinetic energy is selected and analysed by theoretical and numerical means. In particular, the sensitivity of the temperature decay to the non-dimensional parameters Prandtl number ($\mathit{Pr}$) and Eckert number ($\mathit{Ec}$), the latter measuring the intensity of the internal energy production mechanism, is investigated. The time behaviour of the global quantities such as the temperature variance $ \overline{{\theta }^{2} } (t)$ and its destruction rate ${\varepsilon }_{\theta } (t)$ is analysed, and a detailed analysis of the temperature variance spectrum ${E}_{\theta } (k)$ is provided. In the case of a very strong heating mechanism, some important modifications of the temperature dynamics are observed. The time-decay-law exponents of the global physical quantities assume new values, which are governed only by features of the kinetic energy spectrum, while they depend on the shape of ${E}_{\theta } (k)$ in the classical free-decay case. The temperature variance spectrum ${E}_{\theta } (k)$ exhibits two new spectral ranges. One is a convective–production range such that ${E}_{\theta } (k)\propto {k}^{1/ 3} $ is observed for a finite time at all values of $\mathit{Pr}$. In the case of very diffusive fluids with $\mathit{Pr}\ll 1$, a convective–diffusive–production range with ${E}_{\theta } (k)\propto {k}^{- 7/ 3} $ is also detected.
Resonance of the thermal boundary layer adjacent to an isothermally heated vertical surface
Authors: Zhao Yongling , Lei Chengwang , Patterson John C.
Published: April 2013

The instability characteristics and resonance of a natural convection boundary layer adjacent to an isothermally heated vertical surface are investigated using direct stability analyses. The detailed streamwise evolution of the boundary-layer frequencies is visualized via the power spectra of the temperature time series in the thermal boundary layer. It is found that the entire thermal boundary layer may be divided into three distinct regions according to the frequency profile, which include an upstream low-frequency region, a transitional region (with both low- and high-frequency bands) and a downstream high-frequency region. The high-frequency band in the downstream region determines the resonance characteristics of the thermal boundary layer, which can be triggered by a single-mode perturbation at frequencies within the high-frequency band. The single-mode perturbation experiments further reveal that the maximum resonance of the thermal boundary layer is triggered by a perturbation at the characteristic frequency of the boundary layer. For the boundary-layer flow at $\mathit{Ra}= 3. 6\times 1{0}^{10} $ and $\mathit{Pr}= 7$, a net heat transfer enhancement of up to 44 % is achieved by triggering resonance of the boundary layer. This significant enhancement of heat transfer is due to the resonance-induced advancement of the laminar–turbulent transition, which is found to be dependent on the perturbation frequency and amplitude. Evidence from different perspectives revealing the same position of the transition are provided and discussed. The outcomes of this investigation demonstrate the prospect of a resonance-based approach for enhancing heat transfer.
Heat transfer across sheared suspensions: role of the shear-induced diffusion
Authors: Metzger Bloen , Rahli Ouamar , Yin Xiaolong
Published: April 2013

Suspensions of non-Brownian spherical particles undergoing shear provide a unique system where mixing occurs spontaneously at low Reynolds numbers. Through a combination of experiments and simulations, we investigate the effect of shear-induced particle diffusion on the transfer of heat across suspensions. The influence of particle size, particle volume fraction and applied shear are examined. By applying a heat pulse to the inner copper wall of a Couette cell and analysing its transient temperature decay, the effective thermal diffusivity of the suspension, $\alpha $, is obtained. Using index matching and laser-induced fluorescence imaging, we measured individual particle trajectories and calculated their diffusion coefficients. Simulations that combined a lattice Boltzmann technique to solve for the flow and a passive Brownian tracer algorithm to solve for the transfer of heat are in very good agreement with experiments. Fluctuations induced by the presence of particles within the fluid cause a significant enhancement (${\gt }200\hspace{0.167em} \% $) of the suspension transport properties. The effective thermal diffusivity was found to be linear with respect to both the Péclet number ($\mathit{Pe}= \dot {\gamma } {d}^{2} / {\alpha }_{0} \leq 100$) and the solid volume fraction ($\phi \leq 40\hspace{0.167em} \% $), leading to a simple correlation $\alpha / {\alpha }_{0} = 1+ \beta \phi \mathit{Pe}$ where $\beta = 0. 046$ and ${\alpha }_{0} $ is the thermal diffusivity of the suspension at rest. In our Couette cell, the enhancement was found to be optimum for a volume fraction, $\phi \approx 40\hspace{0.167em} \% $, above which, due to steric effects, both the particle diffusion motion and of the effective thermal diffusion dramatically decrease. No such correlation was found between the average particle rotation and the thermal diffusivity of the suspension, suggesting that the driving mechanism for enhanced transport is the translational particle diffusivity. Movies are available with the online version of the paper.
Influence of environment and climate on occurrence of the cixiid planthopperHyalesthes obsoletus, the vector of the grapevine disease ‘bois noir’
Authors: Panassiti Bernd , Breuer Michael , Marquardt Stacey , Biedermann Robert
Published: April 2013

Species distribution models (SDMs), which are well established in many fields of biological research, are still uncommon in the agricultural risk analysis of pest insects. To exemplify the use of SDMs, we investigated the influence of environmental factors on the occurrence ofHyalesthes obsoletusSignoret (Hemiptera: Cixiidae). The planthopper is the only known vector of the grapevine yellows disease ‘bois noir’. The study was conducted in 145 locations in the Baden region of southwest Germany. The planthopper was surveyed on host plant patches, consisting of stinging nettle and/or bindweeds. We used a stratified modelling framework where (1) species presence–absence data were related to an extensive environmental dataset using logistic regressions; and (2) different types of average models were developed based on an information theoretic method. The results show that the incidence ofH. obsoletusis associated to above- as well as below-ground environmental factors, particularly to the amount of fine soil and average annual precipitation. This result was consistent across all average models. The relative importance of other environmental variables was dependent upon the average model under consideration and thus may vary according to their intended use, either the explanation of habitat requirements or the prediction and mapping of occurrence risks. The study showed that SDMs offer a quantification of species’ habitat requirements and thus, could represent a valuable tool for pest management purposes. By providing examples of current issues of grapevine pests in viticulture, we discuss the use of SDMs in agricultural risk analysis and highlight their advantages and caveats.
The cetaceans of Aruba, southern Caribbean
Authors: Luksenburg Jolanda A.
Published: April 2013

Aruba is one of the most densely populated islands in the Caribbean. However, very little is known about its cetaceans. In 2010 and 2011, a total of 19721 km (1686 h) boat-based surveys over nearshore transects resulted in 117 positively-identified sightings comprising eight species. New records are also added for one of three previously-documented species. Five additional species were documented from strandings or reports by others. This brings the total number of cetacean species identified in Aruban waters to 16, of which nine are authenticated here for the first time. Atlantic spotted dolphin (Stenella frontalis(N = 59) and bottlenose dolphin (Tursiops truncatus) (N = 33) were the most frequently observed species, with sightings of both year-round, followed by spinner dolphin (S. longirostris) and false killer whale (Pseudorca crassidens). Additional species recorded are pantropical spotted dolphin (S. attenuata), striped dolphin (S. coeruleoalba), common dolphin (Delphinus capensis), rough-toothed dolphin (Steno bredanensis), short-finned pilot whale (Globicephala macrorhynchus), killer whale (Orcinus orca), Risso's dolphin (Grampus griseus), humpback whale (Megaptera novaeangliae), Bryde's/Eden's whale (Balaenoptera brydei/edeni), sperm whale (Physeter macrocephalus) and an unidentified beaked whale (Mesoplodonsp.). All cetaceans were sighted within 22 km of the coast in relatively shallow waters. Sighting rate was low (0.69 cetacean sightings per 100 km). Sightings of calves and neonates indicate that Aruba may be a nursing or breeding area for some species. The presence of several species of cetaceans in Aruba's coastal waters year-round indicates that status and threat assessments are needed to protect them.
Animacy hierarchy effects on the second language acquisition of attributive psych adjectives
Authors: ZHANG JINGYU
Published: April 2013

This article argues that “animacy” in the context of attributive psych adjectives can be subcategorized into “human,” “human by metonymy,” and “animate” and that these subcategories play a role for Chinese speakers acquiring English. A study that involved an acceptability judgment test found that, in contrast to a group of native controls, the second language (L2) speakers misuse adjectival –ed for adjectival –ing with animate nouns and adjectival –ing for adjectival –ed with human by metonymy nouns, indicating that L2 speakers appeal to an “animacy hierarchy” in determining the meanings of English psych adjectives. There is no evidence in the target language input for such a hierarchy, so the results are consistent with the view that these L2 learners are drawing on universal properties of thematic organization.
A Conversation on The Wooster Group's Hamlet
Authors: LeCompte Elizabeth , Valk Kate , Fliakos Ari , Shevtsova Maria
Published: April 2013

This conversation took place during the Gdansk Festival, 1–10 August 2009, where The Wooster Group performed its internationally acclaimed Hamlet (2006), directed by Elizabeth LeCompte. The conversation, led by Maria Shevtsova and edited by her for publication, was part of the conference organized under the auspices of the Festival by Jerzy Limon, the Festival's director. Here LeCompte and two performers from the company, Kate Valk and Ari Fliakos, discuss how they generated the work, and develop their thoughts in answers to questions from the audience. Later this year The Wooster Group will perform Hamlet on 10–13 August at the Edinburgh International Festival. Maria Shevtsova is the Chair Professor of Drama and Theatre at Goldsmiths, University of London, and Co-Editor of New Theatre Quarterly.
Using Stanislavsky's Toolkit for Shakespeare's Richard III, Part II: Research on the Self in the Play
Authors: Merlin Bella
Published: April 2013

An actor's training continues throughout his/her professional career, yet they rarely have the time or inclination to write in detail about their processes, when building a character, to provide documents for inquisitive peers. In this two-part article, Bella Merlin articulates the discoveries made playing Margaret in Richard III at the Colorado Shakespeare Festival in Summer 2012, directed by internationally acclaimed actor-director Tina Packer (co-founder of Shakespeare and Company with Kristin Linklater in 1978). Merlin highlights how the shift from teacher to actor reactivates the ‘willing vulnerability’ that she demands of her own students. She focuses on Stanislavsky's three avenues of research: on the playtext; on the world of the play and playwright; and on the self. There can be resistance by some theatre practitioners to the application of Stanislavsky's tools to Shakespeare's texts, often due to a perceived over-psychologizing. In these articles Merlin challenges some of these resistances. She demonstrates that Packer's insistence on connecting voice with thought to release the imagination implicitly harnesses Shakespeare's structure with Stanislavsky's underpinnings. Packer also lays emphasis on contemporary resonance, freeing the natural voice, and the significance of Shakespeare's female characters in Richard III for awakening an audience to the consequences of violence. The journey is unsettlingly personal and startlingly global. In Part I, in NTQ 113, Merlin addressed research on the text and research on the play, drawing upon history, biography, accounts of grief, and chilling footage of the Rwandan genocide. In Part II, which follows, she uses the immediacy of a rehearsal journal to address research on the self. Bella Merlin is an actor, writer, and actor-trainer. Acting includes seasons at the National Theatre with Max Stafford-Clark's Out of Joint Company. Publications include The Complete Stanislavsky Toolkit (2007) and Acting: the Basics (2010). She is currently Professor of Acting at the University of California, Davis.
Teatr ZAR's Journeys of the Spirit
Authors: Shevtsova Maria
Published: April 2013

Teatr ZAR has been developing its Gospels of Childhood triptych since 2003, when the company was founded after several years of research in Armenia, Iran, and Georgia. It was in Georgia that ZAR learned polyphonic songs from the Svan oral tradition, which it developed in its unique song theatre. In this article Maria Shevtsova maps the first of a series of expeditions, the latter notably including Greece, Corsica, and Sardinia. She describes how the ancient hymns and chants gathered through direct oral transmission (ZAR's choice of material reflects its interest in the songs of early Christianity) provide the subject matter and the spiritual dimension of the group's performance pieces. The idea of the ‘spiritual’ is here distinguished from the strictly religious/denominational as well as the ritualistic or cultic framings of the word. Details from the triptych show how breath, vibration and energy are the forces of ZAR's sonic compositions in which singing, instrumental music, sound making, and movement are vehicles for experience other than immediate material sensation. Reference is made to ZAR's link to the Grotowski legacy in the song theatre of Poland today. Maria Shevtsova, Chair Professor of Drama and Theatre Arts at Goldsmiths, University of London, wishes to thank the International Research Centre of the Freie Universität Berlin for hosting her research, of which this article is an integral part.
A Grave Situation: An Examination of the Legal Issues Raised by the Life and Death of Charles Byrne, the “Irish Giant”
Authors: Muinzer Thomas L.
Published: April 2013

Charles Byrne was an eighteenth-century celebrity “Irish giant” who requested burial upon nearing death, but whose corpse was procured against his wishes by the surgeon John Hunter. Hunter reduced Byrne's corpse to its skeleton and exhibited it as the centerpiece of his vast anatomical collection. It has since remained on display in the Hunterian Museum, London. In 2011 it was announced that research conducted on the skeleton's DNA has revealed that several Northern Irish families share a common ancestry with Byrne. This article considers the legal issues raised by Byrne's story. The results of fieldwork undertaken by the author in Byrne's native townland are also discussed, where folk tradition suggests that Byrne wished to be buried foremost at a local site remembered today as “the Giant's Grave.”
Modern Antiquities: The Looted and the Faked
Authors: Scott David A.
Published: April 2013

This article discusses some of the issues regarding the acquisition of art and the different philosophical views of some of the main protagonists regarding the reclaiming of art by nation-states, following American museums' acceptance of the 1970 UNESCO Convention, using examples from the Getty Museum and the Metropolitan Museum of Art. The mediation of Native American Graves Protection and Repatriation Act (NAGPRA) claims by conservators is often an important component of the dialogue between museums and native communities. The philosophical and art-historical opinions regarding the value of copies and reproductions of works of art have oscillated from promulgation in the 1860s to outright rejection by the 1920s. In a modernist sense, points of view are once again open to reevaluation as host nations demand back more originals than ever before. Arguments against the claims of nationalist-retentionist countries and those advanced in favor of the claims of nation-states regarding the repatriation of their art are discussed. The problems created by looted art in association with the ever-increasing number of fakes is highlighted, with examples of the issues surrounding pre-Columbian art and some classical antiquities. The utility of copies in relation to the protective value of the authentic piece is discussed in the context of museum examples in which the concept of the utilization of copies for museum display has been accepted in certain cases as desirable.
Digitizing Pacific Cultural Collections: The Australian Experience
Authors: Singh Supriya , Blake Meredith , O'Donnell Jonathan
Published: April 2013

In the absence of specific policies that address the digitization of Pacific cultural collections, it is important to document the practices of Australian museum professionals and cultural experts who deal with close to one-fifth of Pacific cultural objects held in museums. Interviews with 17 museum professionals and cultural experts in Australia help advance reflective practice relating to digitizing Pacific collections. Drawing on principles enshrined in international, regional, and Australian policies and protocols relating to the management of indigenous collections, they favor responsible digitization based on consultation with source and diasporic communities. In order to consult across a region with multiple languages and cultures when time and resources are limited, they begin with areas they know best and when possible, work with curators of Pacific backgrounds. Some practicalities of publishing and protecting digitized images online revolve around validating information about the artifact and going beyond copyright to respect traditional knowledge.
Analysis of Chemical Changes and Microstructure Characterization during Deformation in Ferritic Stainless Steel
Authors: Núñez Andrés , Llovet Xavier , Almagro Juan F.
Published: April 2013

Uni- and biaxial tension deformation tests, with different degrees of deformation, have been done on AISI 430 (EN 1.4016) ferritic stainless steel samples, which had both different chemical compositions and had undergone different annealing treatments. The initial and deformed materials were characterized by using electron backscatter diffraction and backscatter electron imaging in a scanning electron microscope together with electron probe microanalysis. The correlation observed among the chemical compositions, annealing treatment, and strain level obtained after deformation is discussed.
A COSMOPOLITAN IN THE PROVINCES: G. M. GALANTI, GEOGRAPHY, AND ENLIGHTENMENT EUROPE
Authors: NADDEO BARBARA
Published: April 2013

This essay reconstructs the career of the 18th-cetnury Neapolitan publicist Giuseppe Maria Galanti, who championed the genre of anthropological geography in the Kingdom of Naples. Although little attention has been paid to Galanti by the English-language historiography, the person and work of the Neapolitan publicist has loomed large in Italian studies on the Enlightenment. In landmark Italian studies, Galanti has been hailed as a clear-sighted reformer committed to the improvement of socioeconomic conditions within the Kingdom. Likewise, the geographical literature he wrote has been read not as such but rather in light of its program of socioeconomic reform. However important that same program was, undue emphasis upon it has conflated his empirical approach to political geography with a connotation of realism that fundamentally has obscured the place of Galanti's project in the history of anthropology and, in particular, the emergence of European ethnography. By reconstructing the career of Galanti, it is my hope to provide a privileged window on what motivated a precocious ethnographer of Europe to undertake the unusual and arduous project of visiting and describing the provinces of his kingdom, on why he chose to conceptualize the terrain of the Kingdom as an object of philosophical study, and on how he understood his vocation in relation to the alternatives available to him as a man of Enlightenment. While bearing in mind the political aims of Galanti's work, this essay will also return it to the context in which it was first conceived and piloted—namely the ethos, epistemology, and professional culture of the human sciences of the Enlightenment city of Naples, which, it can be said, smacked of a Rousseauian contempt for the “civilization” of the capital, for its learned professions, and for the cosmopolitan theories of Europe's most urbanephilosophes.
INTUITION: THE “UNSEEN THREAD” CONNECTING EMERSON AND JAMES
Authors: CRANE GREGG
Published: April 2013

Recent scholarly comment on the relation between Ralph Waldo Emerson and William James offers an either–or choice between conflating the two thinkers in a proto-postmodern, antifoundationalist cast or dividing them into mutually exclusive categories of idealist believer and relativist skeptic. Contending that neither of these positions captures the pragmatist adumbrations in Emerson or the transcendentalist retentions in James, this essay turns to James's annotations of Emerson's writings as a singularly revealing yet largely neglected source of information about the exact nature of the Emerson–James connection. This evidence points to a pluralistic and distinctly literary formulation of intuitive insight as the key for opening up the Emerson–James relation and for framing it with a precision hitherto missing in discussions of these thinkers. The balance of the essay presents an analytic overview of the various aspects and implications of Emerson's and James's ideas of intuition. Combining doubt and belief, skepticism and faith, realism and idealism, a particular formulation of intuition is the answer that Emerson and James both offer to the problem of modernity—the problem of locating a source of value that is both of the self and beyond the self.
BOOKS AND LIVES, READING AND ACHIEVEMENT
Authors: KELLEY MARY
Published: April 2013

This deeply researched and beautifully crafted study takes as its subject a generation of women who came to maturity in America's Gilded Age. They were scientists and social workers, physicians and educators, and, perhaps most notably, Progressive reformers engaged in the pursuit of social justice. Claiming the newly available opportunities for higher education and professional employment, these women successfully pursued lives in uncharted territory. Barbara Sicherman introduces us to a less visible but equally salient factor in their journey to public identities marked by achievement and acclaim—their sustained and sustaining engagement with reading.
TOP-DOWN RELIGION AND THE DESIGN OF POST-WORLD WAR II AMERICAN PLURALISM
Authors: MOORE R. LAURENCE
Published: April 2013

Academics are falsely rumored to have a low regard for religion. Although Richard Dawkins and Christopher Hitchens, authors of The God Delusion and God Is Not Great, respectively, made atheism a best-selling subject in the United States, it is not coincidental that Hitchens and Dawkins are English. They were educated in a country where a strident antipathy toward religion is not unpatriotic. American atheists with as much brass are rare. Kicking religion around cannot be an American sport because, from colonial to contemporary times, religion has been a central component of American culture. To be sure, a lot of scholarly criticism has been directed at right-wing Christian and Islamic movements. But scholars whose personal views on faith incline them to echo Hitchens's mordant formula that “religion poisons everything” should probably look for a country other than the United States to study. The recent books of historians and sociologists of American religion have taken a tone toward the subject that has ranged from gentle to friendly.
Teaching Partners to Support Communication for Adults with Acquired Communication Impairment
Authors: Ball Laura J. , Lasker Joanne
Published: April 2013

For adults with acquired communication impairment, particularly those who have communication disorders associated with stroke or neurodegenerative disease, communication partners play an important role in establishing and maintaining communicative competence. In this paper, we assemble some evidence on this topic and integrate it with current preferred practice patterns (American Speech-Language-Hearing Association, 2004). Our goals are to help speech-language pathologists (SLPs) identify and describe partner-based communication strategies for adults with acquired impairment, implement evidence-based approaches for teaching strategies to communication partners, and employ a Personnel Framework (Binger et al., 2012) to clarify partners? roles in acquiring and supporting communication tools for individuals with acquired impairments. We offer specific guidance about AAC techniques and message selection for communication partners involved with chronic, degenerative, and end of life communication. We discuss research and provide examples of communication partner supports for person(s) with aphasia and person(s) with amyotrophic lateral sclerosis who have complex communication needs.
Fundamentals of the ImPAACT Program
Authors: Kent-Walsh Jennifer , Binger Cathy
Published: April 2013

Researchers widely agree that working with communication partners is a critical component of any AAC intervention program. However, it can be difficult for clinicians to know how to structure this type of indirect intervention to do more than “tell” communication partners of individuals using AAC what they “should” be doing. The ImPAACT Program is one intervention program that has been documented to yield positive results for clients using AAC. The program involves a structured multistep approach to intervention that clinicians can customize for use across a range of communication partners, clients, and instructional contexts. In this article, we provide an overview of the program's instructional content, approach, and basis of evidence.
Kostet operative Ausbildung Geld? Eine kontrollierte
gesundheitsökonomische Studie auf Grundlage des deutschen DRG-Systems am
Beispiel der primären Knieendoprothetik
Authors: Göbel P. , Piesche K , Randau T. , Wimmer M. , Wirtz D. , Gravius S.
Published: April 2013

Ziel: Die vorliegende kontrollierte Pilotstudie versucht erstmals am
Beispiel der primären Oberflächenersatzendoprothetik des Kniegelenks, die
durch die operative Aus- und Weiterbildung an einem Ausbildungszentrum
entstehenden Mehrkosten vor dem Hintergrund der DRG-Vergütung zu
quantifizieren und diese einer gesundheitsökonomischen Kosten-Erlös-Analyse
zu unterziehen. Methode: Anhand standardisierter Behandlungspfade
wurden konsekutive Patienten der Implantation einer bikondylären
Oberflächenersatzprothese des Kniegelenks unterzogen und durch einen
Facharzt ≥ 1000 (Kategorie A) und ≥ 200 eigenverantwortlich durchgeführten
Primärimplantationen (Kategorie B) im Vergleich zu einem
Weiterbildungsassistenten (Kategorie C) ohne vorhergehende operative
Erfahrung operiert (n = 30 Patienten pro Gruppe). Die evaluierten
Einzelkollektive zeigten hinsichtlich Alter, Geschlecht, Gewicht,
Körpergröße, BMI, ASA und PCCL präoperativ keine signifikanten Unterschiede.
Kostenseitig wurden die Schnitt-Naht-Zeit, PCCL-relevante intra- und
postoperative Komplikationen, die Gabe von Blutprodukten, die Tageskosten
und die stationäre Verweildauer, erlösseitig die DRG, PCCL-Stufe sowie der
CMI erfasst. Ergebnisse: Der Operateur der Kategorie C generiert
Mehrkosten von 1111,7 ± 97 € vs. Kategorie A und 1729,8 ± 152 € vs.
Kategorie B (p > 0,05). Diese resultierten aus einer verlängerten
Schnitt-Naht-Zeit, einer erhöhten EK-Gabe, erhöhten Tageskosten sowie einem
verlängerten stationären Aufenthalt. Durch eine erhöhte Rate PCCL-relevanter
Komplikationen, der Eingruppierung in eine finanziell ertragsreichere DRG
sowie einem erhöhten CMI summierten sich die Mehrerlöse des Operateurs der
Kategorie C auf 474,78 ± 82 € vs. Kategorie A und 150,54 ± 52 € vs.
Kategorie B (p < 0,05). Insgesamt beläuft sich der operative Verlust der
ausbildenden Klinik pro Patient für den Operateur der Kategorie C auf
637 ± 77 € gegenüber Operateur A und 1579,3 ± 137 € gegenüber dem Operateur
der Kategorie B (p > 0,05). Fazit: Operative Ausbildung kostet
Geld. Hieraus resultiert die Forderung der aus- und weiterbildenden
Kliniken, zur sachgerechten Finanzierung der Mehraufwendungen aus operativer
Weiterbildung einen finanziellen Ausgleich gegenüber Häusern zu erhalten,
die keinen Anteil an der ärztlichen Weiterbildung leisten, aber von extern
aus- und weitergebildeten (Fach-) Ärzten profitieren.
Sonografische Dimensionen der Patellasehne von
Hochleistungssportlern
Authors: van Hauten C. , Ostapczuk M. , Baltzer A.
Published: April 2013

Hintergrund: Die sonografische Wertigkeit der Sehnenverdickung als
morphologisches Korrelat der patellaren Tendinopathie gilt zumindest an der
proximalen Insertion des Lig. patellae als unumstritten. Es fehlen jedoch
verbindliche Grenzwerte für Leistungssportler und Normalpersonen. Darüber
hinaus herrscht in der Literatur nach wie vor Uneinigkeit über die klinische
Relevanz von qualitativen Veränderungen wie z. B. der Hypoechogenität der
Sehnenbinnenstruktur. Probanden: 202 Kaderathleten des Deutschen
Leichtathletik-Verbandes und 199 altersgematchte Normalpersonen wurden
sonografisch untersucht. Methoden: 404 Patellasehnen von
Leistungssportlern wurden mittels des tragbaren Ultraschallgeräts „Just
Vision“ mit 398 Patellasehnen von Normalpersonen bezüglich der Sehnendicke
an der (i) proximalen Insertion, der (ii) Taille und der (iii) distalen
Insertion verglichen. Zusätzlich wurden qualitative pathologische
Veränderungen und klinische Beschwerden erfasst. Ergebnisse: Die
Athleten berichteten über mehr klinische Beschwerden und ihre Patellasehnen
waren an allen 3 Messpositionen dicker als die der Normalpersonen (alle
p-Werte < 0,01). Ab einer proximalen Insertionsdicke von 6,0 mm war bei
den Sportlern mit hoher Sicherheit von klinischen Beschwerden auszugehen.
Bei den Athleten war an allen 3 Messpositionen ein Zusammenhang zwischen
Dicke und Symptomatik zu verzeichnen, in der Kontrollgruppe war dies nur an
der proximalen Insertion der Fall. Qualitativ zeigten sich wenig konsistente
Unterschiede zwischen Kader- und Kontrollgruppe. Schlussfolgerung:
Das Ergebnismuster bestätigt die klinische Relevanz der proximalen
Insertionsdicke für die patellare Tendinopathie und liefert kritische
Grenzwerte, die zukünftig hinsichtlich ihrer Prognosefunktion im
Leistungssport weiter untersucht werden sollten. Die Bedeutung von
qualitativ-pathologischen Veränderungen wie Hypoechogenität konnte nicht
sicher belegt werden.
Ion response in a weakly ionized plasma with ion flow
Authors: Kompaneets Roman , Tyshetskiy Yuriy O. , Vladimirov Sergey V.
Published: April 2013

We study the ion response to an initial perturbation in a weakly ionized plasma with ion flow driven by a dc electric field. The analysis is made by extending the classical Landau work [J. Phys. (USSR) 10, 25 (1946)] to the ion kinetic equation including ion-neutral collisions and a dc electric field. We show, in particular, that the complex frequencies of ion waves can be directly found from a known expression for the ion susceptibility [A. V. Ivlev et al., Phys. Rev. E 71, 016405 (2005); V. A. Schweigert, Phys. Rep. 27, 997 (2001)]; this is not obvious from its original derivation, because it only aims to describe the ion response for real frequencies.
Vlasov versus reduced kinetic theories for helically symmetric equilibria
Authors: Tasso H. , Throumoulopoulos G. N.
Published: April 2013

A new constant of motion for helically symmetric equilibria in the vicinity of the magnetic axis is obtained in the framework of Vlasov theory. In view of this constant of motion the Vlasov theory is compared with drift kinetic and gyrokinetic theories near axis. It turns out that as in the case of axisymmetric equilibria [H. Tasso and G. N. Throumoulopoulos, Phys. Plasmas 18, 064507 (2011)] the Vlasov current density thereon can differ appreciably from the drift kinetic and gyrokinetic current densities. This indicates some limitation on the implications of reduced kinetic theories, in particular, as concerns the physics of energetic particles in the central region of magnetically confined plasmas.
Method of time resolved refractive index measurements of x-ray laser heated solids
Authors: Williams G. O. , Chung H.-K. , Vinko S. M. , Künzel S. , Sardinha A. B. , Zeitoun Ph. , Fajardo M.
Published: April 2013

With the advent of new x-ray light-sources worldwide, the creation of dense, uniformly heated plasma states arising from intense x-ray irradiation of solids has been made possible. In the early stages of x-ray solid heating, before significant hydrodynamic motion occurs, the matter exists in a highly non-equilibrium state. A method based on wavefront sensing is proposed to probe some of the fundamental properties of these states. The deflection and absorption of a high harmonic probe beam propagated through the plasma can be measured with a wavefront sensor, and allow for the determination of the complex refractive index (RI) of the plasma, giving a 2D map of the optical properties as function of time in a pump-probe arrangement. A solid heating model has been used to estimate the expected temperatures of x-ray heated thin foils, and these temperatures are used in three separate models to estimate the changes in the refractive index. The calculations show the changes induced on an extreme ultra-violet (XUV) probe beam by a solid density thin foil plasma are significant, in terms of deflection angle and absorption, to be measured by already existing XUV Hartmann wavefront sensors. The method is applicable to a wide range of photon energies in the XUV (10 s to several 100 s of eV) and plasma parameters, and can add much needed experimental data to the fundamental properties of such dense plasma states.
Nanoscopic mechanisms of singlet fission in amorphous molecular solid
Authors: Mou Weiwei , Hattori Shinnosuke , Rajak Pankaj , Shimojo Fuyuki , Nakano Aiichiro
Published: April 2013

Fission of a spin-singlet exciton into two triplet excitons, if realized in disordered organic solid, could revolutionize low-cost fabrication of efficient solar cells. Here, a divide-conquer-recombine approach involving nonadiabatic quantum molecular dynamics and kinetic Monte Carlo simulations identifies the key molecular geometry and exciton-flow-network topology for singlet-fission “hot spots” in amorphous diphenyl tetracene, where fission occurs preferentially. The simulation reveals the molecular origin of experimentally observed two time scales in exciton population dynamics and may pave a way to nanostructural design of efficient solar cells from first principles.
Poloidal flow damping inside transport barriers in a tokamak
Authors: Seol J. , Shaing K. C.
Published: April 2013

The poloidal flow in a tokamak is damped by collisions. Thus, the poloidal damping can be described by the neoclassical theory. The effective poloidal Mach number, Mp, can be of the order of one or higher inside transport barriers in a tokamak. It is found that the poloidal damping rate decreases exponentially as the effective poloidal Mach number increases. The poloidal damping rate is reduced by one order of magnitude in the presence of sonic Mp. We also found that the ion plasma viscosity becomes negligible compared with the electron plasma viscosity when Mp>1.5. In this case, the poloidal flow is damped by electron collisions rather than ion collisions.
Study of X-pinch dynamics using a low current (25 kA) and slower current (400 ns) pulse
Authors: Collins G. W. , Valdivia M. P. , Zick T. , Madden R. E. , Haines M. G. , Beg F. N.
Published: April 2013

We report on experiments examining the dynamics of low current (25 kA), long rise-time (400 ns) X-pinches. The experiments used two- and four-wire 5 μm tungsten X-pinches. We discuss coronal plasma dynamics, X-ray emission, cross-point evolution, and axial column dynamics. We show that the pinch dynamics are akin to those in X-pinches driven by 0.1–1 MA and at rise-rates from 0.25 to 10 kA/ns. We observe soft X-rays (∼1–2 keV range) emitted from the cross point in both two-wire and four-wire X-pinches at about peak current. These results show that compact current generators consisting of 2–4 small capacitors in a simple capacitive discharge circuit can produce good quality pinches for applications in Thomson X-ray scattering and backlighting among others.
Helicon thruster plasma modeling: Two-dimensional fluid-dynamics and propulsive performances
Authors: Ahedo Eduardo , Navarro-Cavallé Jaume
Published: April 2013

An axisymmetric macroscopic model of the magnetized plasma flow inside the helicon thruster chamber is derived, assuming that the power absorbed from the helicon antenna emission is known. Ionization, confinement, subsonic flows, and production efficiency are discussed in terms of design and operation parameters. Analytical solutions and simple scaling laws for ideal plasma conditions are obtained. The chamber model is then matched with a model of the external magnetic nozzle in order to characterize the whole plasma flow and assess thruster performances. Thermal, electric, and magnetic contributions to thrust are evaluated. The energy balance provides the power conversion between ions and electrons in chamber and nozzle, and the power distribution among beam power, ionization losses, and wall losses. Thruster efficiency is assessed, and the main causes of inefficiency are identified. The thermodynamic behavior of the collisionless electron population in the nozzle is acknowledged to be poorly known and crucial for a complete plasma expansion and good thrust efficiency.
Particle-in-cell simulation of an electronegative plasma under direct current bias studied in a large range of electronegativity
Authors: Oudini N. , Raimbault J.-L. , Chabert P. , Meige A. , Aanesland A.
Published: April 2013

A one-dimensional electronegative plasma situated between two symmetrical parallel electrodes under DC bias is studied by Particle-In-Cell simulation with Monte Carlo Collisions. By varying the electronegativity α≡n−/ne from the limit of electron-ion plasmas (negative ion free) to ion-ion plasmas (electron free), the sheaths formation, the negative ion flux flowing towards the electrodes, and the particle velocities at the sheath edges are investigated. Depending on α, it is shown that the electronegative plasma behavior can be described by four regimes. In the lowest regime of α, i.e., α < 50, negative ions are confined by two positive sheaths within the plasma, while in the higher regimes of α, a negative sheath is formed and the negative ion flux can be extracted from the bulk plasma. In the two intermediate regimes of α, i.e., 50 < α < 105, both the electron and the negative ion fluxes are involved in the neutralization of the positive ions flux that leaves the plasma. In particular, we show that the velocity of the negative ions entering the negative sheath is affected by the presence of the electrons, and is not given by the modified Bohm velocity generally accepted for electronegative plasmas. For extremely high electronegativity, i.e., α > 105, the presence of electrons in the plasma is marginal and the electronegative plasma can be considered as an ion-ion plasma (electron free).
The effect of microscopic texture on the direct plasma surface passivation of Si solar cells
Authors: Mehrabian S. , Xu S. , Qaemi A. A. , Shokri B. , Chan C. S. , Ostrikov K.
Published: April 2013

Textured silicon surfaces are widely used in manufacturing of solar cells due to increasing the light absorption probability and also the antireflection properties. However, these Si surfaces have a high density of surface defects that need to be passivated. In this study, the effect of the microscopic surface texture on the plasma surface passivation of solar cells is investigated. The movement of 105 H+ ions in the texture-modified plasma sheath is studied by Monte Carlo numerical simulation. The hydrogen ions are driven by the combined electric field of the plasma sheath and the textured surface. The ion dynamics is simulated, and the relative ion distribution over the textured substrate is presented. This distribution can be used to interpret the quality of the Si dangling bonds saturation and consequently, the direct plasma surface passivation.
Bohm criterion in a dusty plasma with nonextensive electrons and cold ions
Authors: Liu Y. , Liu S. Q. , Zhou L.
Published: April 2013

The Bohm criterion in a dusty plasma containing nonextensively distributed electrons and cold ions is investigated within the framework of probe model including the effects of dust charge fluctuation. It is shown that the critical Mach number upshifts with the decrease of electron nonextensive parameter (qe) and the increase of the ion-to-electron number density ratio (Rn) when the effects of dust charge fluctuation are out of consideration. Once the effects of dust charge fluctuation are included, with the increase of Rn, the critical Mach number increases first, then decreases. The slop of the critical Mach number curves in the region Rn≫1 for qe>1 becomes more gradual than that for qe<1. When critical Mach number is defined with respect to modified ion acoustic wave speed, it should be larger than unity in the case free of dust charge fluctuation. Whereas when Rn≫1, it may be smaller than unity due to the effect of dust charge fluctuation.
Unchannelized dam-break flows: Effects of the lateral spreading on the flow dynamics
Authors: Girolami L. , Wachs A. , Vinay G.
Published: April 2013

In this paper, we used a three-dimensional discrete-grain model (Grains3D) to explore the flow and deposit characteristics of unchannelized dam-break collapses. A series of numerical experiments was performed to predict the behaviour of different granular columns (characterized by different initial aspect ratio a, varying from 0.5 to 18). As observed previously in similar channelized dam-break flows and axisymmetric slumps, the phenomenology of the collapse depends strongly on a, revealing different flow regimes. Small collapsing heaps (a ≲ 3) develop shallow cascades that form deposits characterized by a tail extended by a rounded frontal region. Instead, tall avalanching columns (a ≳ 3) generate dense, fast-moving currents that form a circular final deposit that resembles to those obtained from axisymmetric columns. The conversion from vertical to horizontal momentum was observed to be more efficient in these flows. The aggrading inner tapering region of static grains developed during the flow increases the number of final cascades necessary to adjust the slope of the final deposit, extending the total flow duration from 3 τc in dam-break flows to 7 τc in unchannelized ones. Surprisingly, mean aggradation velocities measured at different locations were observed to be independent of the lateral position, depending primarily on the longitudinal distance from reservoir and the initial aspect ratio. Scaled deposit widths and runouts revealed different power-law dependences on a, exposing a non-isotropic behaviour which tends to form a smooth transition from channelized dam-break flows to axisymmetric slumps.
Toroidal modeling of penetration of the resonant magnetic perturbation field
Authors: Liu Yueqiang , Kirk A. , Sun Y.
Published: April 2013

A toroidal, quasi-linear model is proposed to study the penetration dynamics of the resonant magnetic perturbation (RMP) field into the plasma. The model couples the linear, fluid plasma response to a toroidal momentum balance equation, which includes torques induced by both fluid electromagnetic force and by (kinetic) neoclassical toroidal viscous (NTV) force. The numerical results for a test toroidal equilibrium quantify the effects of various physical parameters on the field penetration and on the plasma rotation braking. The neoclassical toroidal viscous torque plays a dominant role in certain region of the plasma, for the RMP penetration problem considered in this work.
A W-band sixth-harmonic magnetron-type slotted peniotron
Authors: Hu Biao , Li Jiayin , Wu Xinhui , Li Tianming , Li Hao , Wang Haiyang , Zhao Xiaoyun
Published: April 2013

This paper has numerically investigated operating characteristics of a w-band six-harmonic magnetron-type slotted peniotron with 7 vanes. With the new structure design, a high efficiency of 40% w-band 30 kW medium power microwave source has been achieved and the mode competition can be somewhat suppressed. The main advantage of such a peniotron, based on a permanent magnet, is that it can have much more compact size and lower cost, and its operation gap can be greatly reduced.
Nonlinear electron acoustic cyclotron waves in presence of uniform magnetic field
Authors: Dutta Manjistha , Ghosh Samiran , Roychoudhury Rajkumar , Khan Manoranjan , Chakrabarti Nikhil
Published: April 2013

Nonlinear electron acoustic cyclotron waves (EACW) are studied in a quasineutral plasma in presence of uniform magnetic field. The fluid model is used to describe the dynamics of two temperature electron species in a stationary charge neutral inhomogeneous background. In long wavelength limit, it is shown that the linear electron acoustic wave is modified by the uniform magnetic field similar to that of electrostatic ion cyclotron wave. Nonlinear equations for these waves are solved by using Lagrangian variables. Results show that the spatial solitary wave-like structures are formed due to nonlinearities and dispersions. These structures transiently grow to larger amplitude unless dispersive effect is actively operative and able to arrest this growth. We have found that the wave dispersion originated from the equilibrium inhomogeneity through collective effect and is responsible for spatiotemporal structures. Weak dispersion is not able to stop the wave collapse and singular structures of EACW are formed. Relevance of the results in the context of laboratory and space plasmas is discussed.