bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Localization of Ataxin-3 Is Required for the Manifestation of Symptoms in SCA3:In VivoEvidence
Authors: Bichelmeier Ulrike , Schmidt Thorsten , Hübener Jeannette , Boy Jana , Rüttiger Lukas , Häbig Karina , Poths Sven , Bonin Michael , Knipper Marlies , Schmidt Werner J. , Wilbertz Johannes , Wolburg Hartwig , Laccone Franco , Riess Olaf
Published: July 2007

Spinocerebellar ataxia type 3 (SCA3) is an autosomal dominantly inherited neurodegenerative disorder caused by the expansion of a CAG repeat in theMJD1gene resulting in an expanded polyglutamine repeat in the ataxin-3 protein. To study the course of the disease, we generated transgenic mice for SCA3 using full-length ataxin-3 constructs containing 15, 70, or 148 CAG repeats, respectively. Control mice (15 CAGs) were phenotypically normal and had no neuropathological findings. However, mice transgenic for ataxin-3 with expanded polyglutamine repeats were severely affected by a strong neurological phenotype with tremor, behavioral deficits, strongly reduced motor and exploratory activity, a hunchback, and premature death at 3 to 6 months of age. Neuropathological examination by immunohistochemical staining revealed ubiquitin- and ataxin-3-positive intranuclear inclusion bodies in a multitude of neurons. Directing ataxin-3 with 148 CAGs to the nucleus revealed an even more pronounced phenotype with more inclusions and earlier death, whereas mice transgenic with the same construct but attached to a nuclear export signal developed a milder phenotype with less inclusions. These studies indicate that nuclear localization of ataxin-3 is required for the manifestation of symptoms in SCA3in vivo.
Impact of Commitment on Performance Evaluation in the Rostral Cingulate Motor Area
Authors: Michelet Thomas , Bioulac Bernard , Guehl Dominique , Escola Ludovic , Burbaud Pierre
Published: July 2007

Performance evaluation is a prerequisite for behavioral adaptation. Although the anterior cingulate cortex (ACC) is thought to play a central role in error detection, little is known about the electrophysiological activity of this structure during the performance-monitoring process. We directly addressed this issue by training monkeys to perform a Stroop-like task and then recorded neuronal activity in the rostral cingulate motor area (CMAr), a relatively unexplored region of the ACC known to be involved in motor processing. We found that most CMAr neurons responded during the evaluation period to both positive and negative feedback, but neuronal changes were more important after an error than after a successful trial. Interestingly, this performance-monitoring activity was not directly modulated by the degree of difficulty of the cognitive situation because changes in discharge frequency were similar whatever the level of attentional control imposed on the monkey. Firing activity during the evaluation period increased more, however, in erroneously completed than in incompleted trials and when the reward was delivered in an active rather than passive context, indicating that performance evaluation was conditioned by the degree of commitment of the animal to the task. It would thus seem that CMAr neurons could constitute a system for the evaluation of behavioral performance contingent on the subject's commitment to the task.
Are the Effects of the Macroeconomy and Social Policies on Poverty Different in Nonmetro Areas in the United States?*
Authors: Gundersen Craig
Published: July 2007

Abstract The macroeconomy and social policies can have substantial influences on poverty in the United States. In this paper, I investigate whether these influences differ across metro and nonmetro areas. To do so, using a 16‐year panel of state‐level data, I estimate state and year fixed effects models separately for metro and nonmetro areas to see if the effects of the macroeconomy and social policies differ between these two areas. These models are estimated using two measures—the poverty rate and the squared poverty gap—and by family type. I find that cyclical forces have a much stronger effect on the poverty rate in nonmetro areas in comparison to metro areas, but the effects are similar for the squared poverty gap; wage growth has a pronounced effect on poverty in metro areas but no effect in nonmetro areas; and state‐level social policies have slightly larger effects in nonmetro areas, but the effects are small.
From Work to Conversation: Writing and Citizenship in a Global Age
Authors: Laddaga Reinaldo
Published: July 2007

In the last few years, a growing number of writers and artists have begun to develop a new form of verbal art. They no longer devote themselves to individually writing fixed texts destined to be read in solitude and silence. Instead, they are designing mechanisms that enable large and heterogeneous groups to collaborate on projects that combine the production of discourses, the exploration of knowledge about local circumstances, and the invention of potential socialities. These projects intend to foster forms of cosmopolitan citizenship in a globalized world at a time of expanding digital technologies. The article describes some crucial aspects of this process through a reading of two projects: a platform for collaborative translation on the Internet designed by the American artists Warren Sack and Sawad Brooks and an “open-source narrative” by the Italian collective Wu Ming.
“Your Alabaster in This Porcelain”: Judith Gautier'sLe livre de jade
Authors: Yu Pauline
Published: July 2007

This article discusses the history of Judith Gautier'sLe livre de jade(1867), one of the earliest volumes of translations of Chinese poetry published in any European language. It explores the connection between her interest in this project, which Gautier undertook as an amateur student of Chinese, and both the sinological context and the influence of her father, Théophile. Although her command of Chinese was imperfect, Gautier knew more than many have insinuated; her renditions convey important themes of the Chinese poetic tradition and maintain at times an impressive fidelity to the original form. Though she frequently chose to adapt the Chinese verse to an innovative rhythmic prose, her adaptations retain the originals' emotional reticence and imagistic evocativeness–stylistic qualities that resonated with contemporary and succeeding poetic tastes. The collection's remarkable literary and musical afterlife provides an illuminating case in the cultural history of translation, mistranslation, and adaptation.
The Ethics and Practice of Lemony Snicket: Adolescence and Generation X
Authors: Langbauer Laurie
Published: July 2007

Lemony Snicket'sA Series of Unfortunate Eventsis adolescent in the sense provided by Julia Kristeva–it offers critical insight into the breakdown of categories that support representational and ethical certainties. The ethical stance of its author, Daniel Handler, is complicated–urgent, resonant, distressing–caught in the devious irony endemic to metafictional play and to the sensibility of Generation X. Such irony casts light too on literary criticism's changing treatment of the critical subspecialty of children's literature as well as on its renewed but uneasy interest in ethics as revision of past humanism. A Series offers an ethics of practice, one that recognizes its dependence on the impulses it critiques. Just as the books' postmodern orphans improvise in the face of menace that doesn't stop, Handler's irony pictures a world where ethics can never be more than a provisional entente negotiating impossible ideals.
The Entangled Self: Genre Bondage in the Age of the Memoir
Authors: Miller Nancy K.
Published: July 2007

So, I'm just like everybody else. I go to the bookstore. I pick out a book I love. If it says memoir, I know that—that maybe the names and dates and times have been compressed, because that' what a memoir is.

—Oprah Winfrey on Larry King Live, 11 January 2006

I wanted the stories in the book to ebb and flow, to have dramatic arcs, to have the tension that all great stories require. I altered events all the way through the book.

—James Frey, New York Times, 2 February 2006

Sometimes the facts threaten the truth.

—Amos Oz, A Tale of Love and Darkness

Of course it is impossible to tell the truth. For example, how does one know it? I will not belabor the difficulty by telling you how hard I have tried. And if compulsion forces me to tell the truth, it may also lead me into error, or invention.

—Kate Millett, Flying

Is it autobiography if parts of it are not true? Is it fiction if parts of it are?

—Lynda Barry, One Hundred Demons
Uterine Artery Embolization and Future Fertility Potential
Authors: Ong Kee Jiet , Metwally Mostafa , Ledger William L
Published: July 2007

The growing body of evidence concerning the safety and efficacy of uterine artery embolization (UAE) has led to increasing confidence amongst gynecologists and interventional radiologists that UAE can be used safely to treat women with symptomatic fibroids. UAE is clearly preferable for certain subgroups of patients, for example those with increased risks of complications of general anesthesia, those with religious objection to blood transfusion and those wishing to avoid surgical risk. This review of the available literature demonstrates the paucity of information concerning safety and efficacy of UAE for those wishing to conceive. Case reports and series are largely positive. However, there are continuing concerns over the effects of UAE on ovarian and uterine function, and on subsequent pregnancy outcome. More long-term data and randomized controlled trials are required to address these issues. Women who undergo embolization should be told that the effects on pregnancy and the resulting child are uncertain and that there may be long-term implications for the health and development of the offspring. Hence, it is inadvisable to try to conceive following the procedure. Given the available evidence, concern must remain that UAE may lead to significant damage to fertility, with higher risk of miscarriage and adverse pregnancy outcome when compared with open or laparoscopic myomectomy.
Planning models for parallel batch reactors with sequence‐dependent changeovers
Authors: Erdirik‐Dogan Muge , Grossmann Ignacio E.
Published: July 2007

In this article we address the production planning of parallel multiproduct batch reactors with sequence‐dependent changeovers, a challenging problem that has been motivated by a real‐world application of a specialty chemicals business. We propose two production planning models that anticipate the impact of the changeovers in this batch processing problem. The first model is based on underestimating the effects of the changeovers that leads to an MILP problem of moderate size. The second model incorporates sequencing constraints that yield very accurate predictions, but at the expense of a larger MILP problem. To solve large scale problems in terms of number of products and reactors, or length of the time horizon, we propose a decomposition technique based on rolling horizon scheme and also a relaxation of the detailed planning model. Several examples are presented to illustrate the performance of the proposed models. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Venous thromboembolism risk among hospitalized patients: Magnitude of the risk is staggering
Authors: Goldhaber Samuel Z.
Published: July 2007

Quality assessment focuses on areas where measurement is easy and unequivocal. To determine whether high quality hospital medicine is being practiced, a natural target is assessment of the frequency of orders to implement preventive strategies against venous thromboembolism. Patient risk can be readily ascertained, and rigorous clinical trials have vetted effective strategies to prevent deep vein thrombosis and pulmonary embolism. Concentrating on reducing the risk of venous thromboembolism is worthwhile because more than 4 million surgical patients and almost 8 million medical patients warrant specific prophylaxis orders each year in the United States alone. For those who do not receive preventive measures, the result may not be apparent during the index hospitalization. More likely, such patients will tend to develop deep vein thrombosis or pulmonary embolism within the ensuing 90 days, either in a skilled nursing facility or at home in the community. It is now time for us to broaden our approach. What happens in the hospital (such as lapses in good hospital practice) does not necessarily stay in the hospital. Failure to prophylax against venous thromboembolism may have potentially devastating implications for months after hospital discharge. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Tracking open access journals evolution: Some considerations in open access data collection validation
Authors: Sotudeh Hajar , Horri Abbas
Published: July 2007

This article examines the evolution of a collection of open access journals (OAJs,) indexed by the Science Citation Index (SCI; Thomson Scientific Philadelphia, PA) against four validity criteria including a free, immediate, full and constant access policy for at least 5 years. Few journals are found to be wrongly identified as OAJ or to have a dubious access policy. Some delayed journals evolved into gold OA; however, these are scarce compared to the number of journals that withdrew from gold OA to be an embargoed or a partially OAJ. A majority of the journals meet three of the criteria as they provide free and immediate access to their entire contents. Although a lot are found to follow a constant policy, a large number has an OA lifetime shorter than 5 years, due to the high frequency of newly launched or newly converted journals. That is the major factor affecting the validity of the collection. Only half of the collection meets all the requirements.
Impact of research cultures on the use of digital library resources
Authors: Talja Sanna , Vakkari Pertti , Fry Jenny , Wouters Paul
Published: July 2007

Currently, there exists little evidence concerning how various characteristics of research cultures are associated with patterns of use of electronic library resources. The present study addresses this gap by exploring how research‐group membership, across‐fields scattering of literature, and degree of establishment of research area are related to patterns of digital library use. The analytic dimensions are derived from Richard Whitley's (1984) theory of the social and intellectual organization of academic fields. The article represents a first attempt to operationalize Whitley's concepts in a large‐scale study of e‐resources use. The data used in the study were gathered in 2004 by the Finnish Electronic Library (FinElib) through a nationwide Web‐based user questionnaire (N = 900). Membership in a research group significantly increased searching in journal databases, the importance of colleagues as sources of information about electronic articles and journals, and the use of alert services. A significant interaction effect was found between degree of across‐fields scattering of relevant resources and degree of establishment of research fields. A high degree of across‐fields scattering of relevant literature increased the number of journal databases used mainly in less established research areas whereas it influenced the use of journal databases less in established fields. This research contributes to our picture concerning the complex set of interacting factors influencing patterns of use of e‐resources.
Conditionally heteroscedastic factorial HMMs for time series in finance
Authors: Saidane Mohamed , Lavergne Christian
Published: July 2007

In this article, we develop a new approach within the framework of asset pricing models that incorporates two key features of the latent volatility: co‐movement among conditionally heteroscedastic financial returns and switching between different unobservable regimes. By combining latent factor models with hidden Markov chain models we derive a dynamical local model for segmentation and prediction of multivariate conditionally heteroscedastic financial time series. We concentrate more precisely on situations where the factor variances are modelled by univariate generalized quadratic autoregressive conditionally heteroscedastic processes. The expectation maximization algorithm that we have developed for the maximum likelihood estimation is based on a quasi‐optimal switching Kalman filter approach combined with a generalized pseudo‐Bayesian approximation, which yield inferences about the unobservable path of the common factors, their variances and the latent variable of the state process. Extensive Monte Carlo simulations and preliminary experiments obtained with daily foreign exchange rate returns of eight currencies show promising results. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of internal structure changes in black human hair keratin fibers with aging using Raman spectroscopy
Authors: Kuzuhara Akio , Fujiwara Nobuki , Hori Teruo
Published: July 2007

To investigate the internal structure changes in virgin black human hair keratin fibers due to aging, the structure of cross‐sections at various depths of virgin black human hair (sections of new growth hair: 2 mm from the scalp) from a group of eight Japanese females in their twenties and another group of eight Japanese females in their fifties were analyzed using Raman spectroscopy. For the first time, we have succeeded in recording the Raman spectra of virgin black human hair, which had been impossible due to high melanin granule content. The key points of this method are to cross‐section hair samples to a thickness of 1.50‐μm, to select points at various depths of the cortex with the fewest possible melanin granules, and to optimize laser power, cross slit width as well as total acquisition time. The reproducibility of the Raman bands, namely the α‐helix (α) content, the β‐sheet and/or random coil (β/R) content, the disulfide (SS) content, and random coil content of two adjoining cross‐sections of a single hair keratin fiber was clearly good. The SS content of virgin black human hair from the Japanese females in their fifties for the cortex region decreased compared with that of the Japanese females in their twenties. On the other hand, the β/R and α contents of the cortex region did not change. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 134–140, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Evaluation of the influence of the internal aqueous solvent structure on electrostatic interactions at the protein‐solvent interface by nonlocal continuum electrostatic approach
Authors: Rubinstein Alexander , Sherman Simon
Published: July 2007

The dielectric properties of the polar solvent on the protein‐solvent interface at small intercharge distances are still poorly explored. To deconvolute this problem and to evaluate the pair‐wise electrostatic interaction (PEI) energies of the point charges located at the protein‐solvent interface we used a nonlocal (NL) electrostatic approach along with a static NL dielectric response function of water. The influence of the aqueous solvent microstructure (determined by a strong nonelectrostatic correlation effect between water dipoles within the orientational Debye polarization mode) on electrostatic interactions at the interface was studied in our work. It was shown that the PEI energies can be significantly higher than the energies evaluated by the classical (local) consideration, treating water molecules as belonging to the bulk solvent with a high dielectric constant. Our analysis points to the existence of a rather extended, effective low‐dielectric interfacial water shell on the protein surface. The main dielectric properties of this shell (effective thickness together with distance‐ and orientation‐dependent dielectric permittivity function) were evaluated. The dramatic role of this shell was demonstrated when estimating the protein association rate constants. © 2007 Wiley Periodicals, Inc. Biopolymers 87: 149–164, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Enhanced arsenic accumulation by engineered yeast cells expressing Arabidopsis thaliana phytochelatin synthase
Authors: Singh Shailendra , Lee Wonkyu , DaSilva Nancy A. , Mulchandani Ashok , Chen Wilfred
Published: July 2007

Phytochelatins (PCs) are naturally occurring peptides with high‐binding capabilities for a wide range of heavy metals including arsenic (As). PCs are enzymatically synthesized by phytochelatin synthases and contain a (γ‐Glu‐Cys)n moiety terminated by a Gly residue that makes them relatively proteolysis resistant. In this study, PCs were introduced by expressing Arabidopsis thaliana Phytochelatin Synthase (AtPCS) in the yeast Saccharomyces cerevisiae for enhanced As accumulation and removal. PCs production in yeast resulted in six times higher As accumulation as compared to the control strain under a wide range of As concentrations. For the high‐arsenic concentration, PCs production led to a substantial decrease in levels of PC precursors such as glutathione (GSH) and γ‐glutamyl cysteine (γ‐EC). The levels of As(III) accumulation were found to be similar between AtPCS‐expressing wild type strain and AtPCS‐expressing acr3Δ strain lacking the arsenic efflux system, suggesting that the arsenic uptake may become limiting. This is further supported by the roughly 1:3 stoichiometric ratio between arsenic and PC2 (n = 2) level (comparing with a theoretical value of 1:2), indicating an excess availability of PCs inside the cells. However, at lower As(III) concentration, PC production became limiting and an additive effect on arsenic accumulation was observed for strain lacking the efflux system. More importantly, even resting cells expressing AtPCS pre‐cultured in Zn2+ enriched media showed PCs production and two times higher arsenic removal than the control strain. These results open up the possibility of using cells expressing AtPCS as an inexpensive sorbent for the removal of toxic arsenic. Biotechnol. Bioeng. 2008;99: 333–340. © 2007 Wiley Periodicals, Inc.
Studies on neurosteroids XXII. Liquid chromatography–tandem mass spectrometric method for profiling rat brain 3‐oxo‐4‐ene‐neuroactive steroids
Authors: Higashi Tatsuya , Nagahama Akihiro , Mukai Yoshiyuki , Shimada Kazutake
Published: July 2007

A sensitive liquid chromatography–electrospray ionization–tandem mass spectrometric (LC–ESI–MS/MS) method for the simultaneous determination of five 3‐oxo‐4‐ene‐neuroactive steroids, i.e. androstenedione, testosterone (T), progesterone (PROG), 20α‐dihydroprogesterone and 20β‐dihydroprogesterone, in rat brain has been developed and validated. The brain steroids were extracted with methanol‐acetic acid, purified using solid‐phase extraction cartridges and subjected to LC–ESI–MS/MS. The method does not require derivatization. Deuterium‐labeled T and PROG were used as the internal standards, and quantification was based on the selected reaction monitoring mode. This method allowed the reproducible and accurate quantification of the brain neuroactive steroids using 100 mg of tissue; the intra‐ and inter‐assay relative standard deviations were below 4.7 and 4.3%, respectively, and the accuracy values were 97.6–103.2% for all the steroids. The limits of quantitation were 0.1 ng/g tissue for all the steroids. The application of this developed method for the analysis of changes in the brain neuroactive steroid levels by immobilization stress is also presented. Copyright © 2007 John Wiley & Sons, Ltd.
Sentinel lymph node in vulvar cancer
Authors: Hauspy Jan , Beiner Mario , Harley Ian , Ehrlich Lisa , Rasty Golnar , Covens Allan
Published: July 2007

BACKGROUND.

The aim of the study was to assess the feasibility, efficacy, and accuracy of the sentinel lymph node (SLN) procedure in vulvar cancer.

METHODS.

From April 2004 to September 2006, all patients with vulvar cancer, clinical stages I and II, underwent SLN detection, followed by a complete inguinofemoral lymphadenectomy. Demographic, surgical, and pathologic data on all patients were prospectively entered in a database.

RESULTS.

Forty‐two patients underwent the SLN procedure. One patient was excluded from further analysis due to metastases to the vulva. The detection rate for at least 1 SLN per patient was 95%, with bilateral SLNs detected in 46% of patients. There was a trend toward improved ability to detect bilateral SLNs and proximity of the cancer to the midline (r= 0.996;P= .057). No contralateral SLNs were identified in patients with lateral vulvar lesions (>1 cm from the midline). For ‘close‐to‐midline’ (≤1 cm from the midline) lesions, SLNs were detected in 93% of ipsilateral groins and bilateral SLNs were found in 46% of patients, whereas lesions abutting the midline had unilateral and bilateral SLN detected in 100% and 93%, respectively. Sixteen of 41 patients (39%) and 18 of 68 groins (26%) revealed metastatic disease in the lymph nodes; all were correctly identified by the SLN procedure. There were no false‐negative SLN results.

CONCLUSIONS.

SLN dissection is feasible and safe to perform in vulvar cancer. The ability to identify bilateral sentinel inguinal lymph nodes appears to be related to the proximity of the vulvar cancer to the midline. Cancer 2007. © 2007 American Cancer Society.
Colocalization of somatostatin receptor subtypes (SSTR1–5) with somatostatin, NADPH‐diaphorase (NADPH‐d), and tyrosine hydroxylase in the rat hypothalamus
Authors: Kumar Ujendra
Published: July 2007

The hypothalamus is a major site of somatostatin (SST) production and action. SST is synthesized in several hypothalamic nuclei and involved in a variety of functions. Using SST receptor (SSTR)‐specific antibodies, we localized SSTR subtypes in the rat hypothalamus. In addition, we also demonstrated SSTRs colocalization with SST, NADPH‐diaphorase (NADPH‐d), and tyrosine hydroxylase (TH). SSTR1 is strongly localized in neurons in all major hypothalamic nuclei as well as in nerve fibers in the zona externa of the median eminence and the ependyma of the third ventricle. SSTR2 is also well expressed in most regions but with a relatively lower abundance in comparison to SSTR1. In contrast, SSTR3 is localized primarily in the paraventricular nucleus, dorsomedial hypothalamic nucleus, arcuate nucleus, and median eminence. SSTR4‐like immunoreactivity is mainly confined to the arcuate nucleus, ventromedial hypothalamic nucleus, median eminence, and ependymal cells of third ventricle, with the rare SSTR4‐positive neuron in the paraventricular nucleus. SSTR5 is the least expressed subtype occurring only in few cells in the inner layer of the median eminence. Overall, SSTR1 is the predominant subtype, followed by SSTR2, 4, 3, and 5. Combined immunofluorescence, immunocytochemistry, and histochemistry were used to demonstrate SSTRs colocalization with SST, TH, and NADPH‐d. SSTRs colocalization with SST, TH, and NADPH‐d displays in a region and receptor specificity. Colocalization of SST and NADPH‐d with SSTRs in hypothalamic regions was similar, suggesting that SST and NADPH‐d producing cells are same. In contrast, TH was selectively coexpressed with SSTRs in the hypothalamus in a receptor‐specific manner. Taken together, these data suggest that SSTRs may interact with NADPH‐d and TH to exert a physiological role in concert within the hypothalamus. J. Comp. Neurol. 504:185–205, 2007. © 2007 Wiley‐Liss, Inc.
Rate of convergence of the mean curvature flow
Authors: Sesum Natasa
Published: July 2007

We study the flow Mt of a smooth, strictly convex hypersurface by its mean curvature in ℝn + 1. The surface remains smooth and convex, shrinking monotonically until it disappears at a critical time T and point x* (which is due to Huisken). This is equivalent to saying that the corresponding rescaled mean curvature flow converges to a sphere Sn of radius √n. In this paper we will study the rate of exponential convergence of a rescaled flow. We will present here a method that tells us that the rate of the exponential decay is at least 2/n. We can define the “arrival time” u of a smooth, strictly convex, n‐dimensional hypersurface as it moves with normal velocity equal to its mean curvature via u(x) = t if x ∈ Mt for x ∈ Int(M0). Huisken proved that, for n ≥ 2, u(x) is C2 near x*. The case n = 1 has been treated by Kohn and Serfaty [11]; they proved C3‐regularity of u. As a consequence of the obtained rate of convergence of the mean curvature flow, we prove that u is not necessarily C3 near x* for n ≥ 2. We also show that the obtained rate of convergence 2/n, which arises from linearizing a mean curvature flow, is the optimal one, at least for n ≥ 2. © 2007 Wiley Periodicals, Inc.
Collector Probe Measurements of Impurity Fluxes Injected into the Plasma of the T‐10 Tokamak
Authors: Hildebrandt D. , Grote H. , Herrmann A. , Laux M. , Pech P. , Reiner H.‐D. , Wolff H.
Published: July 2007

It is shown that the efflux of impurities injected into the core plasma can be detected by collector probes in the scrape‐off plasma. The time evolution, orientation and radial dependences of these effluxes allow to conclude on the impurity confinement in the core plasma and the scrape‐off plasma. Moreover, recycling effects can also be measured.
A Covariant Hierarchy of Kinetic Equations for Classical Particles and Fields
Authors: De Jagher P. C. , Sluijter F. W.
Published: July 2007

It is shown that several problems, that are met when constructing a covariant statistical theory, can be circumverted demanding that only the resulting equation for the macroscopic entities are covariant whereas only mathematical meaning is ascribed to concepts as phase space and ensemble density. Accordingly a hierarchy of equations for averaged particle distributions and fields and their correlations is derived.
Divertor Plasma Analysis with Collisions
Authors: Dimoff K. , Parbhakar K. J.
Published: July 2007

The high recycling mode of divertor operation is found to depend on the spatial temperature gradient along the divertor length falling within limits set by the ratio of collision frequency with respect to ionization rate. An analytic expression for the neutral particle density necessary to sustain this mode is at least an order of magnitude greater at the divertor throat than previously assumed.
Monte Carlo Calculation of the Effective Penetration Velocity of Re‐Cycling Neutrals in Jet
Authors: Simonini R. , Spence J. , Stangeby P. C.
Published: July 2007

Measured plasma density and temperature profiles have been used as input to a 3‐D Monte Carlo neutral code, NIMBUS, to calculate an effective recycling velocity of neutral deuterium from the JET limiters of ∼1.5×104 m/s (2.5 eV). This result quantitatively explains the observed relation between edge density and central density in JET ohmic discharges. It is found that ≲ 30% of the total ionization occurs within the SOL.
Probe Measurements of Wave Fluctuations Excited in Glow Discharges
Authors: Ohe K. , Tsunoda X.
Published: July 2007

Fluctuations of the electric field, the charged particle density, the electron temperature and the plasma potential are simultaneously measured by a probe in the positive column of helium glow discharge at a few torr gas pressure by exciting a small amplitude ionization wave. It is proposed that these values can be determined by analyzing the probe current.
Ozone Synthesis in an Electric Discharge between Ferroelectric Electrodes at Atmospheric Pressure
Authors: Opalinska T. , Szymanski A. , Sabadil H. , Wagner H.‐E.
Published: July 2007

This paper deals with studies of the ozone synthesis by means of an ac discharge (50 Hz) between two parallel ferroelectric plates under radial oxygen flow conditions at atmospheric pressure. Bariumtitanate based ceramic with ϵ ∽ 6000 was used as ferroelectric material. An important feature of this kind of the discharge is the fact that the operating voltage is well one order of magnitude smaller than that of the silent discharge usually used for the O3 production. Examples of I — U characteristics are discussed. The absorption of light at 253.7 nm wavelength was used to determine [O3] within and downstream of the discharge as function of the O2 flow rate. These results have been examined in terms of a kinetic investigation of the O3 synthesis based on the so‐called plug flow model including the particle balance equations of electrons, O atoms, O2 and O3 molecules, respectively. Thus, the measured decrease of [O3] with increasing flow rate can be explained by the increasing influence of the loss of O3 by convection on the particle balance of O3. Furthermore it is shown that inside the plasma reactor [O3] increases with the radius r. Therefore the data for measured spatial average of [O3] inside the discharge are lower than that of [O3] in the flowing afterglow. The last values are identical with that of [O3] at the exit of the discharge.
Electron Energy Distribution Functions in He‐CO DC Laser Mixture: The Role of Superelastic Electronic Collisions
Authors: Gorse C. , Paniccia F. , Ricard A. , Capitelli M.
Published: July 2007

Electron energy distribution functions (EDF) in He — CO mixtures have been calculated by solving the Boltzmann equation including superelastic vibrational and electronic collisions. The latter include the metastable states CO(a3II) and He(3S). The results show that the presence of superelastic electronic collisions strongly affect EDF. In particular small concentrations of He(3S) modify the shape of EDF, by creating different structures. The net result is the dramatic dependence of electronic and ionization rate coefficients on the concentrations of He(3S) and CO(a3II), while the vibrational rate coefficients are practically unaffected by the presence of these states.
A Pair of Coupled Equations for High Frequency Langmuir Wave and Low Frequency Potential
Authors: Bhakta J. C.
Published: July 2007

A coupled pair of nonlinear equations for the amplitude modulated Langmuir wave and the associated low frequency electric potential wave have been derived by relaxing quasineutrality condition of the frequency motion. Solitary wave solutions exist. It is found that the small correction term due to ion pressure changes the amplitude of the solitary wave.
On the Gravitational Instability of an Ionized Magnetized Rotating Plasma Flowing Through a Porous Medium with other Transport Processes and the Suspended Particles
Authors: Vyas M. K. , Chhajlani B. K.
Published: July 2007

The effects of suspended particles and the finite thermal and electrical conductivities on the magnetogravitational instability of an ionized rotating plasma through a porous medium have been investigated, under varying assumptions of the rotational axis and the modes of propagation. In all the cases it is observed that the Jeans' criterion determines the condition of instability with some modifications due to various parameters. The effects of rotation, the medium porosity, and the mass concentration of the suspended particles on instability condition have been removed by (1) magnetic field for longitudinal mode of propagation with perpendicular rotational axis, and (2) viscosity for transverse propagation with rotational axis parallel to the magnetic field. The mass concentration reduces the effects of rotation. Thermal conductivity replaces the adiabatic velocity of sound by the isothermal one, whereas the effect of the finite electrical conductivity is to delink the alignment between the magnetic field and the plasma. Porosity reduces the effects of both the magnetic field and the rotation, on Jeans' criterion.
On the Instabilities of the Collisionless and Non‐Magnetized Active Plasmas
Authors: Krstić S. R. , Milić B. S.
Published: July 2007

Spontaneously excited instabilities in a uniform, collisionless and non‐magnetized active plasma are studied, under the assumption that the polarisability of its active constituent is due to transitions of only one optical electron between two inversely populated energy levels. The attention is focused on non‐resonant situations in which the modal frequencies of the excited waves differ significantly from the frequency of coherent electromagnetic radiation arising due to the presence of the active constituent. The longitudinal (‘acoustic’) waves in both low and high phase velocity domains, as well as the transverse (‘optical’) waves, are investigated. It is shown that the instabilities excited are most frequently aperiodical, and appear within, a comparatively large wavelength range. Their amplitude increments are evaluated. Under certain particular conditions, specified in the paper, the instabilities turn out to be periodical and to appear in very narrow wavelength bands only. Their modal frequencies and amplitude increments are also evaluated.
A Review of Anode Phenomena in Vacuum Arcs
Authors: Miller H. Craig
Published: July 2007

This paper discusses are modes at the anode, experimental results pertinent to anode phenomena, and theoretical explanations of anode phenomena.

A vacuum are can exhibit five anode discharge modes: (1) a low current mode in which the anode is basically passive, acting only as a collector of particles emitted from the cathode; (2) a second low current mode that can occur if the electrode material is readily sputtered (a flux of sputtered atoms will be emitted by the anode); (3) a footpoint mode, characterized by the appearance of one or more small luminous spots on the anode (footpoints are generally much cooler than the true anode spots present in the last two modes); (4) an anode spot mode in which one large or several small anode spots are present (such spots are very luminous, have a temperature near the atmospheric boiling point of the anode material, and are a copious source of vapor and ions); and (5) an intense are mode where an anode spot is present, but accompanied by severe cathode erosion.

The are voltage is relatively low and quiet in the two low current modes and the intense are mode. It is usually high and noisy in the footpoint mode, and it can be either in the anode spot mode. Anode erosion is low, indeed negative, in the two low current modes, and it is low to moderate in the footpoint mode. Severe anode erosion occurs in both the anode spot and intense are modes.

The dominant mechanism controlling the formation of an anode spot appears to depend upon the electrode geometry, the electrode material, and the current waveform of the particular vacuum are being considered. In specific experimental conditions, either magnetic constriction in the gap plasma, or gross anode melting, or local anode evaporation can trigger the transition. However, the most probable explanation of anode spot formation is a combination theory, which considers magnetic constriction in the plasma together with the fluxes of material from the anode and cathode as well as the thermal, electrical, and geometric effects of the anode in analyzing the behavior of the anode and the nearby plasma.
Some Remarks on the Calculation of Standard Thermodynamic Functions of Diatomic Molecules in SF6 Plasma
Authors: Bartl J. , Bartlovà M.
Published: July 2007

Applying the Mayer's and Geppert‐Mayer's method and the method of direct summation the standard thermodynamic functions of some typical diatomic molecules present in SF6 plasma were calculated. There are given STF data in the temperature region from 100 0 to 15 000K. Some problems of the determination of the STF are discussed.
Indirect Abel Inversions by Power Series and SALS
Authors: Shimizu T. , Horigome T.
Published: July 2007

Derivative‐free Abel inversions named here as ‘Indirect’ method is proved to be far superior to conventional ‘Direct’ method involving derivative term, by numerical experiments. With powerful least‐square fitting method named SALS developed at computer center of Tokyo University, and simple power‐series expansions of emission coefficient e(r) is sufficient without any iterations nor deconvolutions. 10‐test functions often used in literatures are treated and the result of numerical experiments show reconstructions reached to the ultimate of computer precisions.
Pseudopotential Approach to the Thermodynamic Functions of a Dense Hydrogen‐Like Plasma
Authors: Gombert M.‐M. , Minoo H.
Published: July 2007

Pseudopotential approach allows to include the quantum mechanical effects and eliminates the short range classical divergence. At high temperature, when the De Broglie wavelength for a pair of particles, , is larger than the Landau length, Lij, we have to introduce quantum mechanics. For two point‐charge particles without screening, we study the pseudopotential, uij(r), numerically. We give expansions of the pair radial distribution function, gij(r) ( = exp(—βuij(r))) in increasing powers of . For a pair of electrons, exchange effects are taken into account. With these pseudopotentials, we study a dense multicomponent plasma using classical methods and we evaluate thermodynamic functions.
Electrical Conductivity of Partially Ionized Na‐Cs Plasma Mixtures
Authors: Bialas F. , Schmidt K. , Schlanges M. , Redmer R.
Published: July 2007

The electrical conductivity of partially ionized sodium‐cesium plasmas is calculated starting from the electron kinetic equation taking into account the electron‐electron, electron‐ion and the elastic electron‐atom scattering. The transport cross sections follow from the scattering phase shifts solving the corresponding Schrödinger's equation with effective interaction potentials. In order to calculate the plasma composition a coupled law of mass action is used. The electrical conductivity of the plasma mixture is then discussed for densities 1016…1021cm−3and for temperatures 3000 K… 10000 K.
On the Influence of the Pauli Exclusion Principle on the Transport Properties of Dense Coulomb Systems
Authors: Schmidt M. , Janke Th. , Redmer R.
Published: July 2007

Within a model calculation the influence of the Pauli exclusion principle on the electrical conductivity of a fully ionized and degenerate hydrogen plasma is investigated. Basing on a quantum kinetic equation solved with the relaxation time ansatz, the electron — ion contribution to the resistivity is calculated. The thermodynamical T‐matrix for electron — ion scattering processes is evaluated under special account for the Pauli blocking of the intermediate scattering states. The corresponding Bethe — Salpeter equation is solved analytically using a separable approximation of the statically screened potential.

The Pauli exclusion principle has been found to give rise for a considerable enhancement of the transport cross section near the Fermi energy. Thus, degeneracy effects tend to diminish the electrical conductivity in the density — temperature region considered here.
Linear Response Theory and Optical Properties of Nonideal Plasmas
Authors: Röpke G.
Published: July 2007

The interaction between a plasma and radiation is treated within linear response theory. The shape of spectral lines is related to the polarization function which is evaluated in the first order of charged particle density.
Nonideality and Nonlinearity in Reaction‐Diffusion Plasmas
Authors: Kremp D. , Schlanges M. , Bornath Th. , Bonitz M.
Published: July 2007

Reaction and diffusion processes in dense plasmas are investigated on the basis of quantum statistical theory.

Many particle effects lead to nonlinear expressions for reaction and diffusion coefficients.

In the case of ambipolar diffusion and isobarity the plasma is described by only one reaction‐diffusion equation. Travelling front solutions and droplet formation are investigated in the approximation of constant diffusion. The influence of nonlinearity of the diffusion on these solutions as well as the possibility of phase separation via spinodal decompoisition and the formation of stable droplets are discussed.
Reaction‐Diffusion Equations for Dense Plasmas
Authors: Schlanges M. , Bornath Th.
Published: July 2007

A derivation of reaction‐diffusion equations for dense plasmas is given on the basis of quantum kinetic theory. Explicite expressions for the diffusion and reaction rate coefficients with a non‐linear density dependence can be obtained which are valid for nonideal plasmas.
Gravitational Instability of a Rotating Viscous Thermally Conducting Plasma
Authors: Mehta Vijay , Bhatia P. K.
Published: July 2007

This paper deals with the gravitational instability of an infinite homogeneous viscous rotating plasma of finite electrical conductivity in the combined presence of effects of Hall currents, finite Larmor radius (FLR) and thermal conductivity. The ambient magnetic field is assumed to be uniform and acting along the vertical direction. Both longitudinal and transverse modes of wave propagation have been studied. It is shown that Jean's criterion determines the gravitational instability even in the presence of the effects of thermal conductivity, viscosity, finite electrical conductivity, FLR, rotation and Hall currents. Further it is found that while FLR, viscosity and rotation have a stabilizing influence, both the thermal and the electrical conductivities have a destabilizing influence on the gravitational instability of a plasma.
Inreased Power Concentration and its Effect on the Discharge Parameters on the Low Pressure Hg‐Rare Gas Positive Column III. Effects of an Axial Rod
Authors: Kreher J. , Stern W.
Published: July 2007

After the investigation of the influence of current and tube radius on the power concentration of the Hg‐rare gas discharge in the two previous parts, part III deals with the corresponding effects of additional recombination surfaces. The plasma parameters (radiant flux of the resonance lines, field strength, electron density, electron energy distribution function) are measured in a discharge tube with an axial glass rod. With increasing rod diameter and increasing distance from the tube axis radial radiation intensity distribution becomes asymmetric. The field strength increases with the radius of the rod. The dependence of the field strength and that of the radiant flux on the parameters of the discharge do not basically change. The measured UV‐radiation efficiency of the positive column is higher than that of discharges without axial rod for equal tube radius. This is attributed primarily to the changed radial electron density distribution and its effect on the collision processes.
The Harmonic Distortion Factor of the Current of Radio‐Frequency Low‐Pressure Discharges
Authors: Schade K. , Albert M. , Suchaneck G.
Published: July 2007

In order to characterize an r.f. low‐pressure discharge in diode systems which are capacitively coupled to the r.f. generator the content of harmonics in current and voltage is experimentally investigated. The discharge‐conditioned content of harmonics in the voltage is practically negligible. The spectrum of the discharge current is qualitatively and quantitatively dependent on the whole reactor/generator arrangement producing the discharge. For an asymmetrical diode with a self‐excited generator it is shown that the content of harmonics in the discharge current is highly dependent on the radio‐frequency voltage, the d.c. self‐bias of the r.f. electrode, the effective power and the pressure. Conclusions are discussed concerning a connection between the content of harmonics, on the one hand, and carrier‐density modulation and power dissipation at the substrate electrode, on the other hand.
Presheath and Space Charge Sheath Characteristics in Front of a Floating Wall
Authors: Teplanova K.
Published: July 2007

The sheath thicknesses and numbers of collisions from an infinite fluid model of the space between an atomic cold gas plasma and a planar wall are reported in dependence on the normalized ionisation, ion elastic and charge exchange collision frequences. The Bohm criterion validity, ion heating in double layer electric field, volume radiative recombination and related questions are discussed.