bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue and health-related quality of life in elderly patients with and without heart failure in primary healthcare
Authors: Hägglund Lena , Boman Kurt , Olofsson Mona , Brulin Christine
Published: November 2006

Background

Patients with heart failure (HF) in primary healthcare are in many respects not comparable to those in specialized care and the knowledge about different patient groups with and without HF is limited.

Aims

To compare fatigue and health-related quality of life (Hr-QoL) when adjusting for age, gender and social provision in patients with confirmed HF ( n=49) to a group of patients with symptoms indicating HF but without HF (NHF, n=59) and to an age-and sex-matched control-group ( n=40).

Method

A questionnaire including the Multidimensional Fatigue Inventory, the SF-36, and the Social Provisions Scale was used.

Results

The average age in all groups was 78 years. Patients in the HF and NHF groups reported worse physical QoL and more general and physical fatigue than the control group. HF patients had worse general health than the NHF group.

Conclusion

Elderly patients in primary healthcare with confirmed heart failure and patients with symptoms similar to heart failure perceived they had a significantly worse physical QoL and more general and physical fatigue than an age- and sex-matched control group. The similarities between the patient groups indicate the importance of the symptom experience for Hr-QoL.
NESH (Abi‐3) is present in the Abi/WAVE complex but does not promote c‐Abl‐mediated phosphorylation
Authors: Hirao Noriko , Sato Seiichi , Gotoh Tetsuya , Maruoka Masahiro , Suzuki Jun , Matsuda Satoru , Shishido Tomoyuki , Tani Katsuko
Published: November 2006

Abl interactor (Abi) was identified as an Abl tyrosine kinase‐binding protein and subsequently shown to be a component of the macromolecular Abi/WAVE complex, which is a key regulator of Rac‐dependent actin polymerization. Previous studies showed that Abi‐1 promotes c‐Abl‐mediated phosphorylation of Mammalian Enabled (Mena) and WAVE2. In addition to Abi‐1, mammals possess Abi‐2 and NESH (Abi‐3). In this study, we compared the three Abi proteins in terms of the promotion of c‐Abl‐mediated phosphorylation and the formation of Abi/WAVE complex. Although Abi‐2, like Abi‐1, promoted the c‐Abl‐mediated phosphorylation of Mena and WAVE2, NESH (Abi‐3) had no such effect. This difference was likely due to their binding abilities as to c‐Abl. Immunoprecipitation revealed that NESH (Abi‐3) is present in the Abi/WAVE complex. Our results suggest that NESH (Abi‐3), like Abi‐1 and Abi‐2, is a component of the Abi/WAVE complex, but likely plays a different role in the regulation of c‐Abl.
Insights into factors affecting Production and Operations Management (POM) journal evaluation
Authors: Theoharakis Vasilis , Voss Chris , Hadjinicola George C. , Soteriou Andreas C.
Published: November 2006

The paper extends the current literature on peer review journal evaluations by providing a number of insights based on the diversity of Production and Operations Management (POM) research. We provide peer review evaluations for POM research outlets, based on a sampling frame that includes a large number of POM researchers worldwide. More specifically, the paper develops and tests various hypotheses as to whether the perceived quality and relevance of a journal is affected by such factors as: (i) nature of research work (empiricists versus modelers), (ii) society membership, (iii) research productivity, (iv) geographical location, and (v) seniority. Our findings suggest that caution must be exercised when utilizing existing POM journal rankings, as some factors, particularly the difference between empiricists and modelers, may influence journal evaluation. These must be considered when addressing issues such as faculty promotions, tenure, and salary.
Foreign policy, rhetorical action and the idea of otherness: The Czech Republic and Russia
Authors: Kratochvíl Petr , Cibulková Petra , Beneš Vít
Published: November 2006

This article employs the concept of rhetorical action in an analysis of the recent developments in Czech-Russian political relations. Through the discourse analysis of key Russian political speeches and official documents related to the Czech Republic, as well as Czech speeches tackling the same issues, we look at two different rhetorical actions employed by Russia to induce changes in Czech policy. The attempts to make Czech policy unacceptable in the wider community of European democracies were only partially successful. While the first rhetorical action aimed against Czech NATO membership failed, the new diplomatic strategy stressing the need for a “normalization” of relations was successful in transforming Czech policy towards Russia.
Roll cells and disclinations in sheared nematic polymers
Authors: FENG J. J. , TAO J. , LEAL L. G.
Published: November 2006

We use the Leslie–Ericksen theory to simulate the shear flow of tumbling nematic
polymers. The objectives are to explore the onset and evolution of the roll-cell
instability and to uncover the flow scenario leading to the nucleation of disclinations.
With increasing shear rate, four flow regimes are observed: stable simple shear, steady
roll cells, oscillating roll cells and irregular patterns with disclinations. In the last
regime, roll cells break up into an irregular and uctuating pattern of eddies. The
director is swept into the flow direction in formations called ‘ridges’, which under
favourable flow conditions split to form pairs of ± 1 disclinations with non-singular
cores. The four regimes are generally consistent with experimental observations,
but the mechanism for defect nucleation remains to be verified by more detailed
measurements.
The effect of sampling on estimates of lexical specificity and error rates
Authors: ROWLAND CAROLINE F. , FLETCHER SARAH L.
Published: November 2006

Studies based on naturalistic data are a core tool in the field of language acquisition research and have provided thorough descriptions of children's speech. However, these descriptions are inevitably confounded by differences in the relative frequency with which children use words and language structures. The purpose of the present work was to investigate the impact of sampling constraints on estimates of the productivity of children's utterances, and on the validity of error rates. Comparisons were made between five different sized samples of wh-question data produced by one child aged 2;8. First, we assessed whether sampling constraints undermined the claim (e.g. Tomasello, 2000) that the restricted nature of early child speech reflects a lack of adultlike grammatical knowledge. We demonstrated that small samples were equally likely to under- as overestimate lexical specificity in children's speech, and that the reliability of estimates varies according to sample size. We argued that reliable analyses require a comparison with a control sample, such as that from an adult speaker. Second, we investigated the validity of estimates of error rates based on small samples. The results showed that overall error rates underestimate the incidence of error in some rarely produced parts of the system and that analyses on small samples were likely to substantially over- or underestimate error rates in infrequently produced constructions. We concluded that caution must be used when basing arguments about the scope and nature of errors in children's early multi-word productions on analyses of samples of spontaneous speech.
From scalar semantics to implicature: children's interpretation of aspectuals
Authors: PAPAFRAGOU ANNA
Published: November 2006

One of the tasks of language learning is the discovery of the intricate division of labour between the lexical-semantic content of an expression and the pragmatic inferences the expression can be used to convey. Here we investigate experimentally the development of the semantics–pragmatics interface, focusing on Greek-speaking five-year-olds' interpretation of aspectual expressions such as arxizo (‘start’) and degree modifiers such as miso (‘half’) and mexri ti mesi (‘halfway’). Such expressions are known to give rise to scalar inferences crosslinguistically: for instance, start, even though compatible with expressions denoting completion (e.g. finish), is typically taken to implicate non-completion. Overall, our experiments reveal that children have limited success in deriving scalar implicatures from the use of aspectual verbs but they succeed with ‘discrete’ degree modifiers such as ‘half’. Furthermore, children are better at spontaneously computing scalar implicatures than judging the pragmatic appropriateness of scalar statements. Finally, children can suspend scalar implicatures in environments where they are not supported. We discuss implications of these results for the scope and limitations of children's ability to both acquire the lexical semantics of aspectuals and to compute implicatures as part of what the speaker means.
Language input and semantic categories: a relation between cognition and early word learning
Authors: BOROVSKY ARIELLE , ELMAN JEFF
Published: November 2006

Variations in the amount and nature of early language to which children are exposed have been linked to their subsequent ability (e.g. Huttenlocher, Haight, Bryk, Seltzer & Lyons, 1991; Hart & Risley, 1995). In three computational simulations, we explore how differences in linguistic experience can explain differences in word learning ability due to changes in the development of semantic category structure. More specifically, we manipulate the amount of language input, sentential complexity, and the frequency distribution of words within categories. In each of these simulations, improvements in category structure, are tightly correlated with subsequent improvements in word learning ability even when the nature of the input remains the same over time. These simulations suggest that variation in early language environments may result in differences in lexical proficiency by altering underlying cognitive abilities like categorization.
Semantic development in textual contexts during the school years: Noun Scale analyses
Authors: RAVID DORIT
Published: November 2006

The paper examines the nominal lexicon in later language acquisition as a window on linguistic knowledge and usage across childhood and adolescence. The paper presents a psycholinguistically motivated and cognitively grounded analysis of the distribution of ten semantic noun categories (the Noun Scale) across development, modality, and genre. Eighty Hebrew-speaking children (9;0 to 10;0), adolescents (12;0 to 13;0 and 16;0 to 17;0), and a group of adult university graduate students participated in the study. Each produced four different texts: a spoken and written narrative and a spoken and written expository, yielding a total of 320 texts. All lexical noun tokens in each of the 320 texts were analysed to determine their score on the Noun Scale. Results indicate that nominal density, which underlies much of the syntactic architecture of texts, increases dramatically in adolescence, towards adulthood. The paper analyses the developmental patterns of each of the ten Noun Scale categories, showing that the nominal lexicon of schoolaged children is already very different from that of young children in having only a small amount of genuinely concrete nouns, and these too only in narrative texts. The quantitative analysis shows that nouns grow more categorical and abstract with age and schooling, especially in adolescence. Written expository texts are the preferred habitat of abstract, categorical nouns from early on. The systematic qualitative analysis of noun tokens in their textual context demonstrates how the nominal lexicon undergoes fundamental changes that are affected by linguistic, cognitive and social development, in interaction with text genre and modality.
Can you measure attitudinal factors in intercultural communication? Tracing the development of attitudes in e-mail projects
Authors: VOGT KARIN
Published: November 2006

Intercultural competence has acquired an important role in the foreign language classroom. However, we must also come to terms with assessing this highly complex construct if we consider it as a superordinate learning objective. Therefore the components of intercultural communicative competence that go beyond knowledge, especially attitudes, deserve closer attention. On the basis of Byram’s (1997) model of Intercultural Communicative Competence (ICC), an attempt has been made to trace the development of attitudes as part of ICC in computer-mediated intercultural communication. Data was drawn from three e-mail projects that took place between 2001 and 2002. Three different upper-secondary classes at a vocational school in Mainz, Germany (n=64) exchanged e-mails with two groups of US-American undergraduate students in Ohio (n=57) and one group of undergraduate students of English from Tokyo (n=30). Preliminary findings from a telecollaborative seminar with US-American undergraduate teacher students at a German teacher training institution were used to support the data. The main question addressed in the paper is whether attitudinal components of ICC can be measured quantitatively in telecollaborative environments. To do this, specifications and implementation of learning objectives for attitudes as put forward by Byram (1997) are applied to different instruments within the framework of the e-mail projects, including a triangulation of instruments. Instruments include e-mails, critical incidents, essays and interaction journals. When data was ambiguous or incomplete, follow-up interviews were conducted with pupils. Results of the study suggest that it is not possible to measure attitudes with the instruments described, but that they can help teachers to describe evidences of attitudes in interaction and trace developments to provide a basis for feedback.
Integration of computers into an EFL reading classroom
Authors: LIM KANG-MI , ZHONG SHEN HUI
Published: November 2006

This study examined the impact of Computer Assisted Language Learning (CALL) on Korean TAFE (Technical and Further Education) college students in an English as a Foreign Language (EFL) reading classroom in terms of their perceptions of learning environment and their reading performance. The study compared CALL and traditional reading classes over one semester by measuring students’ reading performance. A group of 74 first year English major students were divided evenly into two classes. Both groups were taught by the same teacher and covered the same topics in their weekly two-hour reading lessons. A reading comprehension test was given at the beginning and the end of the semester to measure the students’ performance. A written survey was also administered at the end of the semester. Classroom observations and group interviews with students supplemented the data obtained from the surveys. Analysis of Covariance (ANCOVA) was used for the performance test to explore the differences between the two classes while statistically controlling for the pre-test (covariate). The questionnaires were analyzed by a principle component factor analysis, a repeated-measure ANOVA and a discriminant analysis whereas the interviews with students were analyzed by a content analysis. Students’ performances in the pre-test and the post-test were not significantly different between the two classes. However, the students in the CALL-based English class were more positive in their perceptions of their learning environment than were those in the traditional English class. This study shows that computer technology had a positive impact on students’ perceptions of their learning environment, especially in relation to learning materials and tasks, and with regard to interaction and collaboration with the tutor and other students.
Kardiovaskuläre «Prediction rules»: Was sind Probleme bei der Anwendung? – Resultate der Diskussion in einem Workshop
Authors: Eichler  , Biller-Andorno  , Traindl  , Tschudi  , Bachmann  , Steurer
Published: November 2006

«Guidelines» zur Primärprävention kardiovaskulärer Erkrankungen empfehlen die Bestimmung des kardiovaskulären Gesamtrisikos mittels Risikokalkulatoren (sog. «Prediction rules»). Während die «Prediction rules» als Messinstrumente eingesetzt werden, geben die «Guidelines» Handlungsanleitungen, welche Konsequenzen aus der Berechnung gezogen werden sollten. An einer Tagung wurden Fragen zur Anwendung von «Prediction rules» in der Grundversorgung diskutiert. Die Anwendung scheint in der Praxis einfach zu sein, doch sind einige Barrieren vorhanden, diese Instrumente einzusetzen. Teilweise ist nicht bekannt, wie zuverlässig das Risiko überhaupt berechnet werden kann, teilweise fehlen in den «Prediction rules» Risikofaktoren (z.B. Adipositas), die intuitiv doch wichtig sind und drittens muss zwischen «Prediction rules» und «Guidelines» differenziert werden. In diesem Artikel werden, sofern vorhanden, Antworten auf Fragen, die an dieser Tagung aufgekommen sind, beschrieben.
81-jährige Patientin mit bewegungstherapieresistenten Schmerzen der oberen Extremitäten
Authors: von Garnier  , Bär  , Daikeler  , Rafeiner
Published: November 2006

81-jährige Patientin mit sechsmonatigen Schmerzen der oberen Extremitäten, welche am ehesten mit einer atypischen Polymyalgia rheumatica vereinbar sind und gut auf eine Behandlung mit Steroiden ansprechen. Eine gute klinische Beurteilung ist zur Abgrenzung der Polymyalgia rheumatica von der Riesenzell-arteriitis (GCA) sowie von anderen Differentialdiagnosen unerlässlich und bildet die Grundlage einer kontrollierten Behandlung mit Glukokortikoiden.
Messung der sport- und bewegungsbezogenen Selbstkonkordanz
Authors: Seelig Harald , Fuchs Reinhard
Published: November 2006

Zusammenfassung. Dieser Beitrag stellt die Konstruktion und testtheoretische Überprüfung eines deutschsprachigen Instruments zur Erfassung der sport- und bewegungsbezogenen Selbstkonkordanz (SSK-Skala) vor. Theoretische Grundlage dieser Skala ist die Selbstdeterminationstheorie von Deci und Ryan (1985) sowie das darauf aufbauende Selbstkonkordanz-Modell von Sheldon und Elliot (1999) . Selbstkonkordanz wird definiert als ein Merkmal der Zielintention, in dem zum Ausdruck kommt, wie stark diese Zielintention mit den sonstigen persönlichen Interessen und Werten der Person übereinstimmt (“Ich-Nähe”). Ausgehend von diesem Begriffsverständnis dient die neu konstruierte Skala zur Messung der Ich-Nähe einer sport- und bewegungsbezogenen Zielintention. Die psychometrische Überprüfung des neuen Messinstruments erfolgte in zwei unabhängigen Studien. Im Mittelpunkt von Studie 1 (N = 284; Studierende) stand die faktorenanalytische Konstruktion der Endfassung der SSK-Skala mit insgesamt 12 Items, die sich vier Subskalen zu je drei Items zuordnen lassen. Diese vier Subskalen messen den so genannten intrinsischen, identifizierten, introjizierten und extrinsischen Motivationsmodus. In Studie 2 (N = 337; Normalbevölkerung) konnte die faktorielle Struktur der SSK-Skala bestätigt werden. Reliabilitäts- und Validitätsüberprüfungen mit den Daten beider Studien lassen den Schluss zu, dass mit der SSK-Skala ein konzeptionell und methodisch brauchbares Instrument zur Erfassung der sport- und bewegungsbezogenen Selbstkonkordanz vorliegt.
Self-regulated Learning at the Junction of Cognition and Motivation
Authors: Boekaerts Monique
Published: November 2006

Self-regulated learning has emerged as a powerful new learning theory that is able to promote the transfer of knowledge and skills to real-life situations and make students more independent of their teachers in extending and updating their knowledge base. In recent years, many researchers have shown an interest in developing a theory of self-regulated learning. Considerable research has been generated, but the concept is still too broadly defined and its basic foundations remain poorly understood. The purpose of this paper is to examine the theoretical underpinnings of two strongly related aspects of self-regulated learning that have, until recently, been studied in a relatively isolated fashion. The conceptual framework that is presented in this paper highlights the parallel and reciprocal relationships between components of the cognitive and motivational repertoire and centers on three levels of these repertoires: domain-specific knowledge, strategy use, and goals.
Gender Differences in Burnout
Authors: Pines Ayala M.
Published: November 2006

While studies of gender differences in burnout using the Maslach Burnout Inventory (MBI) report contradictory results, those using the Burnout Measure (BM) indicate a consistent gender difference — women report higher levels of burnout in both their work and their marriages. The present study examined gender differences in burnout among Israelis due to the Palestinian intifada. Ninety seven women and 94 men from six political groups took part in the study. Participants responded to the BM as well as to questions about stresses that were related to their burnout and their ways of coping with it. A two-way analysis of variance (gender by group) indicated that while there was a significant difference among the six groups in levels of burnout, there was no gender difference. However, there were some differences in coping with burnout. The findings are interpreted as supporting an existential perspective on burnout.
TIMED Doppler Interferometer on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite: Data product overview
Authors: Niciejewski R. , Wu Q. , Skinner W. , Gell D. , Cooper M. , Marshall A. , Killeen T. , Solomon S. , Ortland D.
Published: November 2006

The TIMED Doppler Interferometer (TIDI) performs the measurement of upper atmospheric winds on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. This is an optimized single etalon Fabry Perot interferometer that records the slight Doppler shift of individual emission features of the O2 (0,0) atmospheric band. The interferometer operates at a 100% duty cycle obtaining neutral wind altitude profiles on a global basis. The measurements are synoptic and provide an uninterrupted long‐term climatological record of the dynamics in the mesosphere and lower thermosphere regions. The data products from TIDI include (1) apparent line of sight winds and integrated brightness, (2) inverted line of sight winds and volume emission rate, and (3) inverted horizontal neutral wind fields on an evenly spaced track angle/altitude grid. The data products demonstrate an interannual variability in the tidal structure of the mesosphere and the lower thermosphere and an inherent daily geophysical variance.
Subtidal inner shelf currents off Cartagena de Indias, Caribbean coast of Colombia
Authors: Maza Mauro , Voulgaris George , Subrahmanyam Bulusu
Published: November 2006

Seasonal trends in inner shelf subtidal circulation off the coast of Cartagena de Indias, Colombia, are examined through the analysis of current profiles, hydrographic, meteorological and satellite data collected from 1999 to 2002. During the dry season (December–April) the water column is well‐mixed and along‐shelf currents flow southwestward following the steady trade winds. In the rainy season (May–November) the water column experiences continuous events of stratification and the along‐shelf currents flow northeastward, opposing the weak southwestward winds. In the dry season the along‐shelf circulation is mostly driven by wind forcing, while in the rainy season, the circulation is set by an alongshore baroclinic pressure gradient. In the cross‐shelf direction upwelling conditions are observed most of the year and geostrophic balance conditions are found.
Radiative effect of cirrus with different optical properties over the tropics in MODIS and CERES observations
Authors: Choi Yong‐Sang , Ho Chang‐Hoi
Published: November 2006

The radiative effects of cirrus clouds are evaluated based on observations extending over a period of six years (2000–2005) from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Clouds and the Earth's Radiant Energy System (CERES) over the Tropics (25°S–25°N). The cloud radiative effect (CRE) shows a positive sign for optically thin cirrus (total‐column cloud optical depth: τ < 10) and a negative sign for thicker clouds (τ ≥ 10), regardless of the region and season. Since a considerable portion of tropical ice clouds consists in thin cirrus clouds (>60%), their net effective CRE (net CRE × cloud amount) is roughly twice as strong as that of thicker clouds; the modulation of the net radiative flux by variations in thin cirrus (particularly with 1 ≤ τ < 9) dominates—up to 15 W m−2—that by thicker clouds. These results suggest that thin cirrus has a significant effect on the tropical energy balance.
Tracing the location of the reconnection site from the northern and southern cusps
Authors: Trattner K. J. , Petrinec S. M. , Peterson W. K. , Fuselier S. A. , Reme H.
Published: November 2006

Three‐dimensional plasma observations in the cusp have been successfully used to investigate the location of the reconnection site at the magnetopause. This technique uses low‐velocity cutoffs in the precipitating and mirrored magnetosheath population traveling along open cusp field lines, which are then used to estimate the distance to the reconnection line. This distance is subsequently traced back along model magnetic field lines to the magnetopause to identify the location of the reconnection site. In this paper we use data obtained from two widely spaced spacecraft to assess the robustness and consistency in identifying the reconnection site using this technique. Two cusp crossings on 3 March 2003, observed by the Cluster satellites in the Northern Hemisphere and the Polar spacecraft in the Southern Hemisphere during similar solar wind plasma and IMF conditions, are used to trace the location of the reconnection site from two directions. Both estimates point to a reconnection site in the Southern Hemisphere close to the antiparallel reconnection site. The distributions of the trace locations at the magnetopause suggest the existence of a tilted X‐line which crosses that region for these solar wind plasma and interplanetary magnetic field conditions, but the distinction between the antiparallel and the component reconnection scenario could not be conclusively made.
Magnetohydrodynamic simulation of the interaction between interplanetary strong shock and magnetic cloud and its consequent geoeffectiveness: 2. Oblique collision
Authors: Xiong Ming , Zheng Huinan , Wang Yuming , Wang Shui
Published: November 2006

Numerical studies of the interplanetary “shock overtaking magnetic cloud (MC)” event are continued by a 2.5‐dimensional magnetohydrodynamic (MHD) model in heliospheric meridional plane. Interplanetary direct collision (DC)/oblique collision (OC) between an MC and a shock results from their same/different initial propagation orientations. For radially erupted MC and shock in solar corona, the orientations are only determined respectively by their heliographic locations. OC is investigated in contrast with the results in DC (Xiong, 2006). The shock front behaves as a smooth arc. The cannibalized part of MC is highly compressed by the shock front along its normal. As the shock propagates gradually into the preceding MC body, the most violent interaction is transferred sideways with an accompanying significant narrowing of the MC's angular width. The opposite deflections of MC body and shock aphelion in OC occur simultaneously through the process of the shock penetrating the MC. After the shock's passage, the MC is restored to its oblate morphology. With the decrease of MC‐shock commencement interval, the shock front at 1 AU traverses MC body and is responsible for the same change trend of the latitude of the greatest geoeffectiveness of MC‐shock compound. Regardless of shock orientation, shock penetration location regarding the maximum geoeffectiveness is right at MC core on the condition of very strong shock intensity. An appropriate angular difference between the initial eruption of an MC and an overtaking shock leads to the maximum deflection of the MC body. The larger the shock intensity is, the greater is the deflection angle. The interaction of MCs with other disturbances could be a cause of deflected propagation of interplanetary coronal mass ejection (ICME).
Examine the local linear growth rate of collisional Rayleigh‐Taylor instability during solar maximum
Authors: Lee Chien‐Chih
Published: November 2006

This study is the first attempt to examine the effects of terms in the growth rate formula on the magnitude of growth rate during April 1999 to March 2000 (solar maximum). The estimation of linear growth rate is based on the local linear growth rate of collisional Rayleigh‐Taylor instability (Ossakow et al., 1979). The monthly average values of linear growth rate (γ) and associated terms are calculated from the electron profile of Jicamarca digisonde and the atmospheric quantities of MSISE‐90 model under geomagnetic quiet condition. The result shows that the linear growth rate is an essential factor for the development of equatorial spread F (ESF). Furthermore, during this period, the monthly variation in gradient density scale length is neither correlated nor anticorrelated to that in growth rate. In contrast, the monthly variations in the collision frequency and recombination rate are anticorrelated with that in growth rate during this period. Additionally, the altitude range of γ profile is another important factor for the ESF generation.
Introduction to special section on “Results of the National Science Foundation Geospace Environment Modeling Inner Magnetosphere/Storms Assessment Challenge”
Authors: Liemohn Michael W.
Published: November 2006

The National Science Foundation sponsors the Geospace Environment Modeling (GEM) program, devoted to understanding the scientific underpinnings for the creation of a Geospace General Circulation Model. The GEM program is organized into finite‐length campaigns, one of which is the Inner Magnetosphere/Storms (IM/S) Campaign, which is ending in 2006. The final activity of the IM/S Campaign was the IM/S Assessment Challenge (IMSAC), in which several events were selected for intense, community‐wide examination. The primary purposes of the IMSAC were (1) to quantify the ability of the current set of inner magnetospheric models to predict the fields and plasma of this region during storms and (2) to codify the consensus understanding of inner magnetospheric physics. This paper introduces the reader to the IMSAC and presents a general answer to each of the IMSAC goals. In addition, highlights of the scientific advancements during the IM/S Campaign are presented for the plasmasphere, ring current, and radiation belts, along with a synthesis view of the inner magnetosphere. The biggest need for inner magnetospheric research in the near future is the continued progression toward a coupled, interconnected understanding of this region, especially the nonlinear feedback mechanisms between the plasma populations, the electric and magnetic fields, and plasma waves.
Inelastic scattering matrix elements for the nonadiabatic collision B(P1∕22)+H2(Σg+1,j)↔B(P3∕22)+H2(Σg+1,j′)
Authors: Weeks David E. , Niday Thomas A. , Yang Sang H.
Published: November 2006

Inelastic scattering matrix elements for the nonadiabatic collision B(P1∕22)+H2(Σg+1,j)↔B(P3∕22)+H2(Σg+1,j′) are calculated using the time dependent channel packet method (CPM). The calculation employs 1A′2, 2A′2, and 1A″2 adiabatic electronic potential energy surfaces determined by numerical computation at the multireference configuration-interaction level [M. H. Alexander, J. Chem. Phys. 99, 6041 (1993)]. The 1A′2 and 2A′2, adiabatic electronic potential energy surfaces are transformed to yield diabatic electronic potential energy surfaces that, when combined with the total B+H2 rotational kinetic energy, yield a set of effective potential energy surfaces [M. H. Alexander et al., J. Chem. Phys. 103, 7956 (1995)]. Within the framework of the CPM, the number of effective potential energy surfaces used for the scattering matrix calculation is then determined by the size of the angular momentum basis used as a representation. Twenty basis vectors are employed for these calculations, and the corresponding effective potential energy surfaces are identified in the asymptotic limit by the H2 rotor quantum numbers j=0, 2, 4, 6 and B electronic states Pja2, ja=1∕2, 3∕2. Scattering matrix elements are obtained from the Fourier transform of the correlation function between channel packets evolving in time on these effective potential energy surfaces. For these calculations the H2 bond length is constrained to a constant value of req=1.402a.u. and state to state scattering matrix elements corresponding to a total angular momentum of J=1∕2 are discussed for j=0↔j′=0,2,4 and P1∕22↔P1∕22, P3∕22 over a range of total energy between 0.0 and 0.01a.u.
The Lyapunov stability of the N-soliton solutions in the Lax hierarchy of the Benjamin-Ono equation
Authors: Matsuno Yoshimasa
Published: November 2006

The Lyapunov stability is established for the N-soliton solutions in the Lax hierarchy of the Benjamin-Ono (BO) equation. We characterize the N-soliton profiles as critical points of certain Lyapunov functional. By using several results derived by the inverse scattering transform of the BO equation, we demonstrate the convexity of the Lyapunov functional when evaluated at the N-soliton profiles. From this fact, we deduce that the N-soliton solutions are energetically stable.
Design and performance of high uniformity linear filament electron gun
Authors: Iqbal Munawar , Fazal-e-Aleem
Published: November 2006

We describe new features and results from the previously reported [M. Iqbal et al., Rev. Sci. Instrum. 74, 4616 (2003)] thermionic long (up to 140mm) cathode, electromagnetically focused electron beam gun. The gun which was tested up to 50kW (5000mA×10kV) achieves power density of 33kW∕cm2 at the target. The cathode temperature and emission current was uniform over a length of 100mm of the cathode. The beam density profile along the line cathode strongly relates to the temperature distribution along the line cathode. The gun has a remarkable application in heat treatment of large surface area and to coat large substrate surfaces at much faster evaporation rates with lower cost.
Application of imaging plates to x-ray imaging and spectroscopy in laser plasma experiments (invited)
Authors: Izumi N. , Snavely R. , Gregori G. , Koch J. A. , Park H.-S. , Remington B. A.
Published: November 2006

We report recent progress in x-ray diagnosis of laser-plasma experiments using imaging plates. Imaging plates are photostimulable phosphor screens [BaF(Br0.85,I0.15):Eu2+] deposited on flexible metal or plastic substrates. We applied imaging plates to x-ray microscopy of inertial confinement fusion experiments. Self-emission x-ray images of imploded cores were obtained successfully with high-magnification, target-mounted pinholes using imaging plates as detectors. Imaging plates were also used in ultraintense laser experiments at the Rutherford Appleton Laboratory, where small samarium foils were irradiated by high intensity laser pulses from the Vulcan laser system. K-shell x rays from the foil (∼40keV) were used as a line x-ray source for one-dimensional microscopic radiography, and the performance of imaging plates on high-energy x-ray backlit radiography experiments was demonstrated by imaging sinusoidal grooves of 6μm amplitude on a Au foil. Detailed K-shell spectra from Cu targets were also obtained by coupling an imaging plate with a highly ordered pyrolytic graphite crystal spectrometer. The performance of the imaging plates as evaluated in actual laser plasma experiments is presented.
Rotational flow in tapered slab rocket motors
Authors: Saad Tony , Sams Oliver C. , Majdalani Joseph
Published: November 2006

Internal flow modeling is a requisite for obtaining critical parameters in the design and fabrication of modern solid rocket motors. In this work, the analytical formulation of internal flows particular to motors with tapered sidewalls is pursued. The analysis employs the vorticity-streamfunction approach to treat this problem assuming steady, incompressible, inviscid, and nonreactive flow conditions. The resulting solution is rotational following the analyses presented by Culick for a cylindrical motor. In an extension to Culick’s work, Clayton has recently managed to incorporate the effect of tapered walls. Here, an approach similar to that of Clayton is applied to a slab motor in which the chamber is modeled as a rectangular channel with tapered sidewalls. The solutions are shown to be reducible, at leading order, to Taylor’s inviscid profile in a porous channel. The analysis also captures the generation of vorticity at the surface of the propellant and its transport along the streamlines. It is from the axial pressure gradient that the proper form of the vorticity is ascertained. Regular perturbations are then used to solve the vorticity equation that prescribes the mean flow motion. Subsequently, numerical simulations via a finite volume solver are carried out to gain further confidence in the analytical approximations. In illustrating the effects of the taper on flow conditions, comparisons of total pressure and velocity profiles in tapered and nontapered chambers are entertained. Finally, a comparison with the axisymmetric flow analog is presented.
Polarized optical spectroscopy applied to investigate two poly(phenylene-vinylene) polymers with different side chain structures
Authors: Pålsson Lars-Olof , Vaughan Helen L. , Monkman Andrew P.
Published: November 2006

Two related poly(phenylene-vinylene) (PPV) light-emitting polymers have been investigated by means of polarized optical spectroscopy. The purpose of the investigation was to investigate the nature of the interactions in thin films and to examine what impact the difference in side chain structure and molecular weight in poly(2′-methoxy-5-2-ethyl-hexoxy)-1,4-phenylene vinylene (MEH-PPV) and poly(2-(3′,7′-dimethyloctyloxy)-5-methoxy-1,4-phenylene-vinylene) (OC1C10-PPV) has on the electronic and optical properties of the two polymers. Aligning the polymers by dispersing them in anisotropic solvents and stretched films shows that the side chains have an impact on the relative orientations of the transition dipole moments. In anisotropic solvents the linear dichroism is larger for MEH-PPV than for the related polymer OC1C10-PPV, while in stretched films the opposite situation prevails. A lower polarization of the luminescence from OC1C10-PPV, relative to MEH-PPV, was also obtained independent of alignment medium used. The data therefore suggest that while mechanical stretching may align the OC1C10-PPV to a greater degree, the emitting species is distinct from the absorbing species. The circular dichroism (CD) spectra of both polymers undergo dramatic changes when the liquid phase and the solid state (film) are compared. The solution CD spectra shows no evidence of interchain interactions; instead the spectra of both systems indicate a helical conformation of the polymers. The CD spectra of films are dramatically different with the strong Cotton effect being observed. This points to the formation of an aggregate in the film, with an associated ground state interaction, an interchain species such as a physical dimer, or a more complex higher aggregate.
Positron annihilation studies of defects and interfaces in ZnS nanostructures of different crystalline and morphological features
Authors: Biswas Subhajit , Kar Soumitra , Chaudhuri Subhadra , Nambissan P. M. G.
Published: November 2006

Nanostructures of ZnS, both particles and rods, were synthesized through solvothermal processes and characterized by x-ray diffraction and high resolution transmission electron microscopy. Positron lifetime and Doppler broadening measurements were made to study the features related to the defect nanostructures present in the samples. The nanocrystalline grain surfaces and interfaces, which trapped significant fractions of positrons, gradually disappeared during grain growth, as indicated by the decreasing fraction of orthopositronium atoms. The crystal vacancies present within the grains also trapped positrons. These vacancies further agglomerated into clusters during the thermal treatment given to effect grain growth. The positron lifetime was remarkably large at extremely small grain sizes (∼1.5nm) and this was attributed to the occurrence of quantum confinement effects, as verified through optical absorption measurements. Positron lifetimes in ZnS nanorods increased with increasing content of cubic phase in the samples and this observation is assigned to the annihilation of positrons in sites with increased cubic unit cell volume. The Doppler broadened spectra also indicated qualitative changes consistent with these observations.
a
-
b
axis-oriented lanthanum doped Bi4Ti3O12 thin films grown on a TiO2 buffer layer
Authors: Simões A. Z. , Pianno R. F. C. , Ries A. , Varela J. A. , Longo E.
Published: November 2006

a - b axis-oriented, lanthanum doped Bi4Ti3O12 (BLT) thin films with a TiO2 rutile buffer layer deposited on Pt∕Ti∕SiO2∕Si substrates were grown by the soft chemical method. Butterfly dielectric behavior has been achieved and can be ascribed to the ferroelectric domain switching. The remanent polarization and the coercive voltage for the film deposited on TiO2 buffer layer were 22.2μC∕cm2 and 1.8V, respectively. Random-oriented BLT films showed a reduction in switching polarization when compared to the a-b axis-oriented films. Due to the excellent physical properties, these films are a promising candidate for use in lead-free applications in ferroelectric devices.
Surface mass diffusion and step stiffness on V(011)
Authors: Ondrejcek M. , Rajappan M. , Swiech W. , Flynn C. P.
Published: November 2006

By step fluctuation experiments on V(011) thin films grown on (112¯0) α-Al2O3, using low energy electron microscopy, we determine the coefficient of surface mass diffusion Ds in the temperature range of 1170K<T<1560K, centered near 0.6Tm, with the melting temperature Tm=2183K for V. As is common to annealed V, Nb, and Ta in UHV, submonolayer coverages of O were present on the otherwise clean and well-defined surface. We obtain Ds=0.8exp (−1.43eV∕kBT)cm2∕s for this temperature interval. Compared to Nb(011), the step stiffness obtained from the measurements is relatively small and isotropic at ∼60meV∕nm. Sublimation is made visible by uphill step flow above 1460K, with a temperature dependence consistent with the known cohesive energy.
Band gap shift in the indium-tin-oxide films on polyethylene napthalate after thermal annealing in air
Authors: Han H. , Mayer J. W. , Alford T. L.
Published: November 2006

Indium-tin-oxide (ITO) thin films on polyethylene napthalate (PEN) with high carrier concentration (∼1021∕cm3) have been grown by electron-beam deposition without the introduction of oxygen into the chamber. The electrical properties of the ITO films (such as, carrier concentration, electrical mobility, and resistivity) abruptly changed after annealing in the air atmospheres. In addition, optical transmittance and optical band gap values significantly changed after heat treatment. The optical band gap narrowing behavior is observed in the as-deposited sample because of impurity band and heavy carrier concentration. The influence of annealing in air on the electrical and optical properties of ITO∕PEN samples can be explained by the change in the free electron concentration, which is evaluated in terms of the oxygen content. Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy analyses are used to determine the oxygen content in the film. Hall effect measurements are used to determine the dependence of electrical properties on oxygen content.
Domain switching anisotropy in poled lead titanate zirconate ceramics under orthogonal electromechanical loading
Authors: Li Fa-Xin , Fang Dai-Ning , Liu Yuan-Ming
Published: November 2006

Domain switching process in aged lead titanate zirconate ceramics after hyper-TC (TC is the Curie temperature) poling was studied under two types of orthogonal electromechanical loading: (i) axial electric field E3 coupled with lateral compression stresses σ11 and (ii) axial compression stresses σ33 coupled with lateral electric fields E1. It is found that in the lateral direction, both the coercive field and the switchable polarization are significantly smaller than that in the original poling direction and that the lateral coercive field does not decrease but increase with the increasing axial compression, which contradicts with the widely accepted domain switching criterion by Hwang et al. [Acta. Metall. Mater. 43, 2073 (1995)]. The alignment of defect dipoles during aging, together with its effect on domain switching, is employed to explain the observed domain switching anisotropy. Furthermore, the domain stabilizing effect of aligned defect dipoles may lead to a design of large electrostriction actuators.
Numerical investigation of edge flame propagation characteristics in turbulent mixing layers
Authors: Chakraborty Nilanjan , Mastorakos E.
Published: November 2006

The statistical behavior of the displacement speed of an edge flame originating from localized ignition of inhomogeneous reactants in decaying isotropic turbulence is studied based on three-dimensional direct numerical simulations (DNS) with simplified chemistry. The ignition is simulated by introducing a source term in the energy transport equation, which deposits a given amount of energy over a specified time duration. The flame structure is shown to exhibit a tribrachial structure where a diffusion flame is stabilized on the stoichiometric mixture fraction isosurface alongside two premixed flame branches on fuel-rich and fuel-lean mixtures. The speed at which the fuel mass fraction YF isosurface moves with respect to an initially coincident material surface at the point where these three flames meet (commonly referred to as triple point) is taken as the edge flame displacement speed. Its statistics are explained in terms of the reaction, normal diffusion, and tangential diffusion components of the density-weighted displacement speed Sd*. It is shown that the statistical behavior of Sd* and its components in response to the scalar dissipation rate and local flame curvature are strongly dependent on the statistical behavior of the fuel mass fraction gradient ∣∇YF∣ in response to local flame curvature and mixture fraction gradient ∣∇ξ∣. It is shown that the extent of premixed and nonpremixed contributions determines the ∣∇YF∣ variation with ∣∇ξ∣, whereas the flow acceleration due to heat release and dilatation field determines the curvature response of ∣∇YF∣. The variation of Sd* in response to scalar dissipation rate and curvature are shown to be non-monotonic in nature and is found to be consistent with previous results based on two-dimensional DNS with detailed chemistry and experimental studies. This nonmonotonic behavior has been shown here to exist even in the absence of detailed chemistry and is explained in terms of the fluid-dynamical aspects of flame-turbulence interaction.
Oscillatory jets and instabilities in a rotating cylinder
Authors: Duguet Yohann , Scott Julian F. , Le Penven Lionel
Published: November 2006

The viscous flow inside a closed rotating cylinder of gas subject to periodic axial compression is investigated numerically. The numerical method is based on a spectral Galerkin expansion of the velocity field, assuming axisymmetry of the flow. If the forcing amplitude is weak and the angular forcing frequency is less than twice the rotation rate, inertial waves emanate from the corners, forming conical oscillatory jets which undergo reflections at the walls. Their thickness is O(E1∕3), or O(E1∕4) for particular forcing frequencies, where E is the Ekman number. For larger forcing amplitudes, the conical pattern breaks down. When the forcing frequency is resonant with a low-order inertial mode, the flow can undergo two types of parametric instabilities: a mode-triad resonance, and a subharmonic instability. The combination of both these mechanisms provides a possible route to quasiperiodicity of the flow.