bluuebunny/crossref_metadata_2025 huggingface dataset:
Visual inspection with acetic acid and cytology as screening methods for cervical lesions in Cameroon
Authors: Doh A.S. , Nkele N.N. , Achu P. , Essimbi F. , Essame O. , Nkegoum B.
Published: April 2005

Objectives

To assess the accuracy of visual inspection with acetic acid (VIA) as a screening method for cervical lesions.

Methods

VIA and cytological smears were carried out on the cervices of non‐pregnant women aged 30–60 years with no previous history of cervical cancer. Cervices with aceto white lesions or positive Pap smears, and one in ten negative cervices (control), were biopsied.

Results

5010 women were enrolled, 4813 (96.1%) were screened. 4767 (99.%) had adequate cytology smears. 574 (11.9%) had colposcopy. 1743 biopsies were obtained of which 528 were controls. The sensitivity of VIA was 70.4% versus 47.7% for Pap smear. VIA specificity was 77.6% versus 94.2% for Pap smear; PPV for VIA was 44.0% versus 67.2% for Pap smear; and NPV for VIA was 91.3% versus 87.8% for Pap smear.

Conclusions

VIA has acceptable test qualities and may in low resource settings be implemented as a large scale screening method.
DPOAE‐Grams in Patients with Acute Tonal Tinnitus
Authors: Gouveris Haralampos , Maurer Jan , Mann Wolf
Published: April 2005

OBJECTIVE:

To investigate cochlear outer hair cell function in patients with acute tonal tinnitus and normal or near‐normal hearing threshold.

STUDY DESIGN AND SETTING:

Prospective controlled study in an academic tertiary health center. Distortion products of otoacoustic emissions (DPOAE)‐grams of 32 ears with acute tonal tinnitus and normal hearing or minimal hearing loss were compared with those of 17 healthy nontinnitus ears.

RESULTS:

Tinnitus ears exhibited relatively increased amplitudes of DPOAE at high frequencies (4‐6.3 kHz) when compared with the group of healthy ears and relatively decreased DPOAE amplitudes at middle frequencies (1650‐2400 Hz). Statistically significant (P < 0.01) increased mean values of DPOAE amplitudes were observed only at a frequency of f2 equal to 4.9 kHz.

CONCLUSIONS AND SIGNIFICANCE:

These findings suggest an altered functional state of the outer hair cells at a selected high‐frequency region of the cochlea in ears with acute tonal tinnitus and normal or near‐normal hearing threshold.
The Bone‐Anchored Hearing Aid in Children: A Surgical and Questionnaire Follow‐Up Study
Authors: Priwin Claudia , Granström Gösta
Published: April 2005

OBJECTIVES:

The main objectives were to evaluate the surgical techniques and problems seen in children with bone‐anchored hearing aids (BAHA) as well as to determine the children's attitudes toward BAHA.

STUDY DESIGN:

A retrospective study of 41 children with unilateral BAHA was conducted. Surgical recordings were investigated and a questionnaire was distributed.

RESULTS:

Surgery was performed as a 2‐stage procedure. Available bone thickness was measured in 29 patients and found to be on average 2.5 mm. Thin temporal bone necessitated bone augmentation in 8 patients. Of the implants, 70.5% were installed in contact with the dura or the sigmoid sinus. Implant failures were seen in 9.1% and adverse skin reactions appeared in 7.6% of the patients. Twenty‐seven patients responded to the questionnaire, 19 were still BAHA users. Overall, these patients were very content with their BAHAs.

CONCLUSION:

BAHA is a good alternative in children despite limited thickness of the temporal bone.
Reliability of the “Sydney,” “Sunnybrook,” and “House Brackmann” Facial Grading Systems to Assess Voluntary Movement and Synkinesis after Facial Nerve Paralysis
Authors: Coulson Susan E. , Croxson Glen R. , Adams Roger D. , O'dwyer Nicholas J.
Published: April 2005

OBJECTIVE:

To investigate the extent of within‐system reliability and between‐system correlation for the “Sydney” and “Sunnybrook” systems of grading facial nerve paralysis, and to examine the interobserver reliability and agreement of the “House Brackmann” grading system.

STUDY DESIGN:

A fixed‐effects reliability study in which 6 otolaryngologists viewed videotapes of patients with facial nerve paralysis.

SETTING:

University and medical Centers.

PATIENTS:

Patients with unilateral lower motor neurone facial nerve dysfunction greater than 1 year after onset, none of whom had undergone surgical reanimation procedures.

INTERVENTION:

Twenty‐one patients with facial nerve paralysis were videotaped while they performed a protocol of facial movements. Six otolaryngologists viewed the videotapes and scored them with the Sydney and Sunnybrook systems, and then gave a House Brackmann grade.

MAIN OUTCOME MEASURE:

The 3 systems of grading facial nerve paralysis were evaluated and compared with the use of intraclass correlation coefficients, Pearson's weighted kappa, and percentage exact agreement values.

RESULTS:

The Sydney and the Sunnybrook systems had good intrasystem reliability and high intersystem association for the assessment of voluntary movement. Grading of synkinesis was found to have low reliability both within and between systems. The House Brackmann system had substantial reliability as shown by weighted kappa but had a percentage exact agreement of 44%.

CONCLUSIONS:

For clinical grading of voluntary movement, there is good correlation between ratings given on the Sydney and Sunnybrook systems, and within each system there is good reliability. The assessment of synkinesis was far less reliable within, and less related between, systems. Although the reliability of the House Brackmann system was found to be high, examination of individual grades revealed some wide variation between trained observers.
Greedy or Needy? Forest Administration and Landowners' Attitudes in South-Western France during the Eighteenth Century
Authors: GRAHAM HAMISH
Published: March 2005

On paper the forestry service of Old Regime France looked impressive. Backed by wide-ranging legislation, officers of the Eaux et Forêts enjoyed extensive powers; like other public officials of the time, they exercised both judicial and administrative functions. Their rich records of offences and disputes have attracted the attention of forest historians, although we know much less about their other role, as overseers of a national plan for woodland management. This article seeks to remedy that neglect by focusing on the effectiveness of the forest administration in south-western France, where most of the woodlands were private property. Evidence is drawn from the forms used by landowners to notify the Eaux et Forêts of an intention to cut mature timber. Various details suggest that the forestry officials' information was far from complete, especially given the problems of distance and a lack of standardised units for measurement. Examination of marginal comments provides a closer insight into landowners' attitudes. Overall, increasing numbers of woodland proprietors may have complied with the foresters' reporting regime, but many relied on misinformation to prevent the central state and its agents from interfering in the exploitation of their timber.
The Land that Richard Jefferies Inherited
Authors: JONES ERIC L.
Published: March 2005

This article comprises the annual Birthday Lecture of the Richard Jefferies Society as it was delivered in October, 2004. The text sketches the economic, social and environmental history of Jefferies' period (the 1860s, 1870s and 1880s), drawing inter alia on his works and referring especially to his home district in north-east Wiltshire. It alludes, firstly, to the fortunes and environmental effects of both intensive and ‘tumbledown’ arable farming. Second, it describes the creation of sporting estates and the letting of sporting rights as swift responses by some landowners to falling cereal prices. Third, the text points to under-investment in education and non-agricultural activities as hampering adjustment to the depression, and shows that Jefferies was a free trader who grasped that rapid and extensive food importation and labour emigration would have been a proper response. A related paper, Eric L. Jones, ‘Richard Jefferies’ Writing Criticised and Defended', is to appear in the Richard Jefferies Society Journal in April, 2005.
The Transformation of Sherwood Forest in the Twentieth Century: The Role of Private Estate Forestry
Authors: KOTTLER DUNCAN , WATKINS CHARLES , LAVERS CHRIS
Published: March 2005

Despite the demise of many landed estates in the twentieth century, the creation of the Forestry Commission and consequent massive afforestation, over two-thirds of British woodland remained in the hands of private land owners at the end of the century. Little research has been carried out into the changing role of landed estates in forming and maintaining woodland landscapes in this period. This paper examines forestry on the Thoresby estate, Sherwood Forest, Nottinghamshire using a wide range of sources. It demonstrates the dynamic nature of this landscape during the twentieth century. Rather than being a slowly changing woodland landscape, it has been transformed through interventions by land agents and landowners in response to changing social, economic and government policy pressures.
Towards a Palestinian Arabic Emotive Lexicon: An Invitation for Discussion
Authors: Alon Ilai
Published: March 2005

This paper invites discussion on the proposition of compiling a Palestinian Arabic emotive lexicon that would incorporate in its entries, in addition to cognitive definitions, the emotions, associations, connotations, metaphors, idioms, and non-verbal expressions that are commonly associated with a given word. My main working hypothesis is that semantics must address emotions, i.e., that words, and not only their peripheral elements, carry emotive content. Ignoring these, empathies (temporary term), the manner in which expression is “understood” within a given culture, is partial, at best. Research is to be carried out both quantitatively, in field research, and qualitatively, by literary analysis. The many theoretical, as well as the practical, pitfalls of this suggestion are taken into consideration. The paper's appendices include a sample entry and a sample questionnaire.
Situating Sufism and Yoga
Authors: Ernst Carl W.
Published: March 2005

“The natives of all unknown countries are commonly called Indians” Maximilian of Transylvania, De molucco (1523)
The Assassination of King Het'um II: The Conversion of The Ilkhans and the Armenians
Authors: Stewart Angus
Published: March 2005

On November 17, 1307, the Armenian king, Het'um II, was assassinated by a Mongol, recently converted to Islam, the noyan Bularghu. In this paper I will look at this assassination, which has often been seen as significant in the context of the conversion of the Mongols of Persia to Islam, and also at the effects, or perceived effects, of that conversion, especially regarding Ilkhanid foreign policy. I shall consider the attitude of the Ilkhans to the small Armenian kingdom centred on Cilicia, now in south-eastern Turkey, which, by 1307 had shrunk from the size and importance it had enjoyed in the middle of the thirteenth century. First, I intend briefly to describe Armenian relations with the Mongols, from the irruption of the latter until about 1307; then I shall discuss the assassination, the sources and reasons for it; next I shall look at the conversion of the Mongol rulers of Persia to Islam, and any effects that this may have had on Ilkhanid foreign policy; finally I shall consider how both this conversion and the assassination have been interpreted by historians, and what this event actually shows us about the effects of the Mongol Ilkhans' conversion to Islam on their relationship with their subject, Christian, Armenian satellite.
Faktorenstruktur verschiedener neuropsychologischer Tests
Authors: Bühner Markus , Schmidt-Atzert Lothar , Grieshaber Edmund , Lux Armin
Published: March 2005

Zusammenfassung: Im Rahmen einer retrospektiven Untersuchung wurden die neuropsychologischen Testwerte von 153 hirngeschädigten Patienten mit einer Faktorenanalyse analysiert und die Faktorenstrukur bestimmt. Die Faktorenanalyse ergab für die 33 ausgewählten Kennwerte der 8 durchgeführten Tests (Wiener Testsystem: Reaktion auf Licht und Ton, TAP: Alertness tonisch und phasisch, Go/Nogo, geteilte Aufmerksamkeit, Revisionstest, Test d2, IST-70 Merken und Wiedererkennen, HAWIE-R Zahlennachsprechen, Benton-Test, LPS 1 + 2, 3, 4, 9 und 10) die folgenden interpretierbaren Faktoren: Gedächtnis (F1), Alertness (F2), weitgehend sprachfreie Intelligenz (F3), geteilte Aufmerksamkeit (F4), Konzentrationsfähigkeit (F7) und Alertnessänderung (F9). Die verwendeten Aufmerksamkeitstests weisen damit eine differenzierte Binnenstruktur auf, die alleine anhand der Testbezeichnung nicht erkennbar ist. Es zeigt sich, dass Fehler und Tempo unabhängige Kennwerte der Aufmerksamkeitsleistung darstellen. Aufmerksamkeit, Gedächtnis und Intelligenz konnten voneinander abgegrenzt werden.
Psychometrische Analysen des Rivermead Behavioural Memory Tests bei chronisch mehrfach beeinträchtigten Abhängigkeitskranken
Authors: Hoffmann Markus , Weithmann Gerd , Rothenbacher Hermann
Published: March 2005

Zusammenfassung: Bei 120 chronisch mehrfachgeschädigten Alkoholabhängigen wurde u. a. der Rivermead Behavioural Memory Test durchgeführt. Die Daten dienten als Grundlage für verschiedene psychometrische Analysen. In einer Itemanalyse konnte eine gute innere Konsistenz (α = 0.87) festgestellt werden. Die Rasch-Analyse ergab eine eindimensionale Lösung, die für die Homogenität der Items bezüglich der gemessenen Funktion spricht. In der Hauptkomponentenanalyse ergab sich ein Faktor mit einem Eigenwert deutlich über 1. Daher können keine Gruppen von Personen gebildet werden, die ähnliche Muster von Gedächtnisbeeinträchtigungen aufweisen. Für die Therapie bedeutet dies, dass alle Gedächtnisfunktionen gleichermaßen betroffen sein können und dass es nicht möglich ist, diese mit wenigen Screening-Items abzubilden.
Ambulante Klinische Kinderneuropsychologie
Authors: Heubrock Dietmar , Petermann Franz
Published: March 2005

Zusammenfassung: Obwohl die ambulante neuropsychologische Rehabilitation von Kindern und Jugendlichen eine wichtige und unverzichtbare Therapiephase auf dem Weg zu einer langfristigen (Re-)Integration neurologisch kranker Kinder darstellt, sind entsprechende Therapieangebote im ambulanten Sektor bis heute extrem selten. Zudem liegen derzeit keine Bedarfsanalysen für ambulante neuropsychologische Behandlungsmaßnahmen bei Kindern und Jugendlichen vor. Die vorliegende Untersuchung stellt erstmalig die Ergebnisse einer empirischen Studie über Zuweisungsdiagnosen, Zuweisungswege und ausgewählte neuropsychologische Befunde für eine ambulante neuropsychologische Inanspruchnahmepopulation von Kindern und Jugendlichen mit Hirnfunktionsstörungen vor.
Entwicklungsneuropsychologische Aspekte kindlicher Epilepsien
Authors: Mayer H. , Haverkamp F.
Published: March 2005

Zusammenfassung: Neuropsychologische Auswirkungen von epileptischen Erkrankungen werden bis heute sowohl von der klinischen wie auch wissenschaftlichen Neuropsychologie wenig beachtet und wenig Bedeutung beigemessen. Der folgende Artikel zeigt klinisch bedeutsame Aspekte dieser Erkrankung insbesondere im Kindesalter auf, die dringend einer differenzierteren neuropsychologischen Diagnostik und Therapie bedürfen. Interessante und innovative Perspektiven, die die Epileptologie für die Entwicklungsneuropsychologie anbieten kann, werden vorgestellt.
Zur Fremdeinschätzung von Schülerselbstkonzepten durch Lehrer und Mitschüler
Authors: Pohlmann Britta , Möller Jens , Streblow Lilian
Published: March 2005

Zusammenfassung: Das “Internal/External Frame of Reference Modell” (I/E-Modell) von Marsh (1986) postuliert, dass zur Ausbildung fachspezifischer Selbstkonzepte neben sozialen Vergleichen (externaler Bezugsrahmen) auch dimensionale Vergleiche (internaler Bezugsrahmen) herangezogen werden. Dimensionale Vergleiche sind Vergleiche der eigenen Leistungen in zwei Domänen. In der vorliegenden Untersuchung wurde geprüft, ob das I/E-Modell auch für fremdeingeschätzte Selbstkonzepte gilt. Dazu wurden die mathematischen und verbalen Selbstkonzepte von N = 1114 Schülerinnen und Schülern sowie die Fremdeinschätzungen der Selbstkonzepte von Seiten jeweils eines Mitschülers und ihrer N = 48 Mathematiklehrer erfasst. Für die Selbstbeschreibungen der Schüler zeigten sich erwartungsgemäß sowohl positive Effekte des externalen als auch negative Effekte des internalen Bezugsrahmens. Lehrer und Mitschüler hingegen verwendeten zur Einschätzung der Selbstkonzepte anderer hauptsächlich soziale Vergleichsinformationen und ließen dimensionale Vergleiche weitgehend unberücksichtigt.
Rauchen ist tödlich, Computerspiele machen aggressiv?
Authors: Trautwein Ulrich , Lüdtke Oliver , Beyer Beate
Published: March 2005

Zusammenfassung: Epistemologische Überzeugungen sind pädagogisch relevante subjektive Annahmen von Lehrern und Lernenden über die Natur menschlichen Wissens und Wissenserwerbs. In mehreren Studien wiesen Studierende “harter” Studiengänge weniger günstige epistemologische Überzeugungen auf als Studierende “weicher” Studiengänge. Allerdings ist umstritten, inwieweit bislang verwendete Erhebungsinstrumente geeignet sind, solche Unterschiede zu messen. Bei einer Stichprobe von 108 Studierenden unterschiedlicher Fachrichtungen wurde deshalb neben bewährten Fragebogenskalen ein neu entwickeltes Instrument zur Erfassung theorienspezifischer epistemologischer Überzeugungen eingesetzt, bei dem Überzeugungen über Grenzen wissenschaftlicher Erkenntnis anhand von zehn konkreten wissenschaftlichen Theorien untersucht werden. Die Auswertung erfolgte mehrebenenanalytisch und erbrachte folgende Hauptbefunde. Erstens zeigte sich auf Theorienebene eine hohe Varianz in der Beurteilung der einzelnen Theorien. Zweitens wurden Theorien, die die Teilnehmer gut kannten, positivistischer beurteilt. Drittens waren schwache, jedoch signifikante Effekte des Studienfachs sowie der allgemeinen epistemologischen Überzeugungen zu verzeichnen. Die Diskussion erörtert kritisch eine Mehrebenenperspektive in der Theorie und empirischen Forschung zu epistemologischen Überzeugungen.
Leistung und emotionales Erleben im Fach Mathematik
Authors: Goetz Thomas , Pekrun Reinhard , Zirngibl Anne , Jullien Simone , Kleine Michael , vom Hofe Rudolf , Blum Werner
Published: March 2005

Zusammenfassung: Die vorliegende Studie konzentriert sich auf den Zusammenhang von fachspezifischer Leistung und emotionalem Erleben im Kontext Schule. Es wird ein Mediationsmodell (nach Pekrun, Goetz, Titz & Perry, 2002 ) vorgestellt, in welchem Wirkungen sowohl individueller Leistung als auch mittlerer Schulklassenleistung auf individuelles Emotionserleben dargestellt sind. Zur Prüfung der Modellannahmen werden individuelle und auf Klassenebene aggregierte Leistungswerte sowie deren Wirkungen auf individuelles Emotionserleben anhand von Mehrebenenanalysen simultan modelliert. Die längsschnittliche Untersuchung wurde an einer Stichprobe von 78 Schulklassen (N = 1762 Schülerinnen und Schüler) am Ende der 5. und 6. Jahrgangsstufe mathematikspezifisch durchgeführt. Während individuelle Leistung der 5. Jahrgangsstufe zur Erhöhung des Freudeerlebens und zur Minderung des Angsterlebens in der 6. Jahrgangsstufe führt, zeigen sich für die Leistung der Schulklasse die umgekehrten Effekte: Ein hohes Leistungsniveau der Klasse führt zu einer Verringerung individueller Freude und zu einer Erhöhung individueller Angst. Diese Ergebnisse sind theoriekonform und vergleichbar mit Ergebnissen zu dem im Rahmen der Selbstkonzeptforschung bereits häufig untersuchten Big-fish-little-pond-Effekt (BFLPE; Marsh, 1987 ). Theoretische und praktische Implikationen werden aufgezeigt.
Wie generell ist das Modell?
Authors: Schilling Susanne R. , Sparfeldt Jörn R. , Rost Detlef H.
Published: March 2005

Zusammenfassung: Im Rahmen der Genese schulischer Selbstkonzepte postuliert das “Internal/External Frame of Reference”-Modell (I/E-M, Marsh, 1986 ) zwei (gegenläufige) Vergleichsprozesse: Neben sozialen Vergleichen spielen auch dimensionale Vergleiche (Leistungen in verschiedenen Fächern werden einander gegenübergestellt) eine Rolle. Diese sollen zu Kontrasteffekten führen, d. h. zu negativen Pfaden der Leistung in einem Fach (z. B. Mathematik) auf das Selbstkonzept in einem anderen Fach (z. B. Deutsch). Empirische Untersuchungen konzentrierten sich bislang hauptsächlich auf Mathematik und (Mutter-)Sprache. An N = 1632 Gymnasiasten haben wir das I/E-M strukturgleichungsbasiert für zwei sprachliche (Deutsch, Englisch), zwei naturwissenschaftliche (Physik, Mathematik) und zwei nicht eindeutig einer Domäne zugehörige Fächer (Geschichte, Biologie) überprüft. Neben Kontrasteffekten traten auch Assimilationseffekte (positive Pfade der Leistung in einem Fach auf das Selbstkonzept in einem anderen Fach) auf. Zukünftig müsste präzisiert werden, welche Faktoren das Ergebnis dimensionaler Vergleiche (Assimilation oder Kontrast) moderieren.
Rechenleistung bei Grundschülern
Authors: Grube Dietmar , Barth Ulrike
Published: March 2005

Zusammenfassung: Achtundvierzig Viertklässler bearbeiteten einen Mathematiktest, Aufgaben zur Addition und Subtraktion im Zahlenraum bis 20 (Abruf basaler arithmetischer Fakten) sowie Aufgaben der Gedächtnisspanne vorwärts (als Maß für die Kapazität der phonologischen Schleife nach Baddeley, 1986 ) und rückwärts (als Maß für die Leistungsfähigkeit der zentralen Exekutive). Die durchgeführten Zusammenhangsanalysen unterstützen die Annahme von Einflüssen der zentralen Exekutive, der phonologischen Schleife und der Qualität des basalen arithmetischen Faktenabrufs auf die Rechenleistung von Viertklässlern. Das Muster von Zusammenhängen weist auf eine herausragende Rolle der zentralen Exekutive in ihrem Einfluss auf Faktenabruf und fortgeschrittenes Rechnen hin.
Diffusion of Ca and F in haplogranitic melt from dissolving fluorite crystals at 900°–1000°C and 100 MPa
Authors: Gabitov R. I. , Price J. D. , Watson E. B.
Published: March 2005

The diffusion rates of Ca and F into haplogranitic melt were determined by concentration profiles in glasses produced by dissolving fluorite crystals into haplogranitic melt at 900°–1000°C and 75–100 MPa. Starting products were synthesized from oxides of haplogranitic composition at two aluminosities ([Na2O + K2O]/Al2O3 = 1.05 and 1.68). Fluorite crystals or crystal powders were coupled with powders or solid cylinders of haplogranitic glass. Water was added to the runs, resulting in two runs at H2O = 1.20 and 1.40 wt% and three runs thought to be water saturated. The materials were then subjected to the conditions of interest in either a Stellite cold seal apparatus or an internally heated pressure vessel. Electron microprobe traverses of the quenched glasses produced in these experiments revealed negative concentration gradients in Ca and F away from the fluorite‐glass boundary. These gradients are comparable to an error function solution (in the first approximation) for specific Ca and F diffusivities (DCa and DF, respectively). The Ca diffusion coefficient increased from 3.36 ± 0.19 · 10−9 to 2.16 ± 0.28 · 10−8 cm2/s and F diffusivity increased from 1.16 ± 0.09 · 10−8 to 6.59 ± 0.62 · 10−8 cm2/s as temperature increased from 900° to 1000°C. These diffusivities are comparable to other published melt diffusion data for the dissolution of multicomponent minerals where the diffusants move independently. Calcium and fluorine diffusivities increase from 2.77 ± 0.09 · 10−9 to 2.16 ± 0.28 · 10−8 cm2/s and from 2.27 ± 0.10 · 10−8 to 6.59 ± 0.62 · 10−8 cm2/s, respectively, with increasing water content at 1000°C, likely due to melt depolimerization. The large difference in the concentrations of Ca (C0Ca) and F (C0F) at the fluorite‐glass interface suggests that these two elements diffuse independently in the melt. In contrast, the concentration gradient for Na parallels that of F, suggesting complexing between these two elements.
Interpretation of very long period tremors at Ambrym volcano, Vanuatu, as quasi‐static displacement field related to two distinct magmatic sources
Authors: Legrand D. , Rouland D. , Frogneux M. , Carniel R. , Charley D. , Roult G. , Robin C.
Published: March 2005

A 3‐component broadband seismometer (STS‐2) has been deployed on the SW slope of Ambrym, Vanuatu, a large‐caldera volcano with two persistent lava lakes from July to November 2000. Well‐polarized Very Long Period Tremors (18–22s; VLPTs) occurred quite continuously, whereas other seismic signal with periods of 9s, 6–7s, 5s, 2.3–2.7s, 1.95s and 1s were intermittent. VLPTs signals show two clearly distinct directions pointing towards the caldera. Polarization orientations suggest two sources: the first one, and the most active, fits with the zone from which silicic lava flows erupted in 1986, in the central‐to‐eastern part of the caldera. The second one corresponds to the active zone formed by the complex Marum volcanic center and the Benbow cone, in the western part of the depression structure. The depths are estimated between 2.7–2.9 km with respect to sea level. VLPTs are interpreted as the quasi static‐displacement field of two nondestructive sources. They indicate the persistent continuing magmatic activity beneath the eastern floor of the caldera, although no volcanic activity is observed in this area, and the more obvious, but less active, corresponding to the lava lakes. These data also corroborate the complex internal structure of the Ambrym caldera, suggested by geological data and bimodal magmatism (basaltic, ∼50% SiO2, and silicic, ∼60% SiO2).
The effect of ocean mixing parametrisation on the enhanced CO2 response of the Southern Hemisphere midlatitude jet
Authors: Stone Dáithí A. , Fyfe John C.
Published: March 2005

The use of a more physically based parametrisation scheme for sub‐grid scale ocean mixing produces a more spatially uniform surface warming in the Southern Hemisphere in transient global warming simulations of the CCCma climate model than when an older scheme is used. Here we examine the effect of this different warming pattern on the tropospheric circulation response, by comparing simulations of two versions of the model implementing these two mixing parametrisations. It is found that use of either scheme produces a southward shift of the midlatitude jet, but that this shift is considerably smaller when the new parametrisation is implemented. These results suggest that the magnitude of the Southern Annular Mode‐like response noted in some global warming simulations may be sensitive to the representation of ocean processes.
Impact of halogen monoxide chemistry upon boundary layer OH and HO2 concentrations at a coastal site
Authors: Bloss W. J. , Lee J. D. , Johnson G. P. , Sommariva R. , Heard D. E. , Saiz‐Lopez A. , Plane J. M. C. , McFiggans G. , Coe H. , Flynn M. , Williams P. , Rickard A. R. , Fleming Z. L.
Published: March 2005

The impact of iodine oxide chemistry upon OH and HO2 concentrations in the coastal marine boundary layer has been evaluated using data from the NAMBLEX (North Atlantic Marine Boundary Layer Experiment) campaign, conducted at Mace Head, Ireland during the summer of 2002. Observationally constrained calculations show that under low NOx conditions experienced during NAMBLEX (NO ≤ 50 pptv), the reaction IO + HO2 → HOI + O2 accounted for up to 40% of the total HO2 radical sink, and the subsequent photolysis of HOI to form OH + I comprised up to 15% of the total midday OH production rate. The XO + HO2 (X = Br, I) reactions may in part account for model overestimates of measured HO2 concentrations in previous studies at Mace Head, and should be considered in model studies of HOx chemistry at similar coastal locations.
Cloud condensation nucleus production from nucleation events at a highly polluted region
Authors: Laaksonen Ari , Hamed Amar , Joutsensaari Jorma , Hiltunen Laura , Cavalli Fabrizia , Junkermann Wolfgang , Asmi Ari , Fuzzi Sandro , Facchini Maria Cristina
Published: March 2005

Atmospheric nucleation events have received increasing attention as a potentially important source of aerosol particles affecting climate and human health. Here, we report 2.5 years of continuous nucleation observations from San Pietro Capofiume, Italy (44°39′N, 11°37′W). We show that nucleation events occur frequently in the Po Valley region, even though the region is rather polluted with high pre‐existing particle concentrations. The nucleation events are often very intensive, and the newly formed particles can grow to sizes as large as 100–200 nm in diameter within a few hours. Our calculations of the enhancement of particle number concentrations in different size ranges and comparison with steady‐state and regional emission estimates indicate that the nucleation events produce a significant fraction of particles larger than 100 nm, and thus constitute an important source of cloud condensation nuclei (CCN).
Observations of gravity wave breakdown into ripples associated with dynamical instabilities
Authors: Li Feng , Liu Alan Z. , Swenson Gary R. , Hecht James H. , Robinson Walter A.
Published: March 2005

The breakdown of a high‐frequency quasi‐monochromatic gravity wave into small‐scale ripples in OH airglow was observed on the night of 28 October 2003 at Maui, Hawaii (20.7°N, 156.3°W). The ripples lasted ∼20 min. The phase fronts of the ripples were parallel to the phase fronts of the breaking wave. The mechanism for the ripple generation is investigated using simultaneous wind and temperature measurements made by a sodium (Na) lidar. The observations suggest that the wave breaking and the subsequent appearance of ripples were related to dynamical (or Kelvin‐Helmholtz) instabilities. The characteristics of the ripples, including the alignment of the phase fronts with respect to the wind shear, the motion of the ripples, and the horizontal separation of the ripple fronts were consistent with their attribution to Kelvin‐Helmholtz billows. It is likely that the dynamical instability was initiated by the superposition of the background wind shear and the shear induced by the wave. The wind shear, the mean wind acceleration, and the propagation of the breaking wave were found to be in the same direction, suggesting that wave‐mean flow interactions contributed significantly to the generation of the strong (>40 m/s/km) wind shear and instability.
Ancient oceans in the northern lowlands of Mars: Evidence from impact crater depth/diameter relationships
Authors: Boyce Joseph M. , Mouginis‐Mark Peter , Garbeil Harold
Published: March 2005

We present depth (d) and diameter (D) data for 2269 Martian impact craters in the diameter range 6–216 km, distributed over ∼11.52 × 106 km2 of terrain that samples several geologic settings and the full range of latitudes and elevations throughout the northern lowlands of Mars. Our data indicate that there are three major crater types that fall into two major populations, those craters that contain Vastitis Borealis formation (VBF) and those that do not. The deepest type 1 craters comprise a Late Hesperian/Early Amazonian‐age population that does not contain VBF. Type 2, type 3, and subdued type 1 craters comprise a population of Hesperian‐age craters partially buried by the VBF. The unique d/D distribution of type 3 craters and photogeologic evidence suggest an erosional style for the VBF that requires sublimation processes, indicating that the VBF contained a substantial amount of ice. Type 3 craters occur throughout the northern lowland plains at elevations below −2400 m. If the VBF is a sedimentary deposit left by a large body of standing water in the northern lowlands of Mars, then the northern lowland plains contained a body of water with a volume of ∼6 × 107 km3 or the equivalent of a 430 m global ocean during the Late Hesperian/Early Amazonian. This also implies that the VBF contains ∼4 × 106 km3 of material, in agreement with the estimated amount of material eroded from the outflow channels surrounding Chryse basin and washed into the northern lowlands.
Na incorporation into Cu(In,Ga)Se2 for high-efficiency flexible solar cells on polymer foils
Authors: Rudmann D. , Brémaud D. , Zogg H. , Tiwari A. N.
Published: March 2005

Incorporation of a small amount of sodium into Cu(In,Ga)Se2 (CIGS) absorbers for thin-film solar cells is well known to enhance conversion efficiencies. Usually, Na is added in a way such that it is present during CIGS growth and therewith influences the growth kinetics. We have used post-deposition Na in-diffusion into as-grown, Na-free absorbers and observed typical efficiency improvements. This suggests that in general the main positive Na effect originates from changes in the electronic absorber properties rather than from modification of CIGS growth kinetics. At low substrate temperatures, Na impedes CIGS phase formation. This may explain why absorbers grown at substrate temperatures below 450°C in the presence of Na yield inferior cells compared with post-deposition-treated CIGS. We have developed post-deposition Na incorporation for the processing of flexible CIGS solar cells on polyimide substrates. A conversion efficiency of 14.1% under AM1.5 standard test conditions was independently measured. This represents the highest reported efficiency of any solar cell grown on a polymer substrate to date.
Determination of order parameter of L1–FePd nanoparticles by electron diffraction
Authors: Sato Kazuhisa , Hirotsu Yoshihiko , Mori Hirotaro , Wang Zhouguang , Hirayama Tsukasa
Published: March 2005

Long-range order (LRO) parameters of two-dimensional dispersed single-crystalline 10-nm-sized FePd nanoparticles with the L10 structure have been determined accurately by electron diffraction in transmission electron microscopes (TEMs) under accelerating voltages of 300kV and 1kV. Diffraction patterns by exciting hh0 systematic reflections effectively reduced the numbers of diffracted beams and simplified the thickness dependence of intensity ratio I110∕I220 for 110 and 220 reflections. Mean thickness of the nanoparticles was estimated to be 7.8nm by electron holography. The relation between the intensity ratio and the order parameter was calculated on the basis of multiple-scattering intensity calculation. By comparing the relation and experimentally obtained intensity ratios, the order parameters of 0.65 and 0.79 were obtained using 300-kV TEM for FePd nanoparticles after annealing at 873K for 3.6 and 36ks, respectively. Also, the order parameter of 0.82 was obtained using 1-MV TEM for the same specimen annealed at 873K for 36ks. These order parameters were determined using the Debye–Waller factors for bulk Fe and Pd. The order parameter decreased about 7.3% when a very large Debye–Waller factor as large as 0.01nm2 was assumed. A combination of electron diffraction under the conditions of hh0 systematic reflections and the diffraction experiment at the high accelerating voltage makes the LRO parameter analysis easy and correct.
Laser ablation of AlN films grown on sapphire substrate
Authors: Safadi Mona R. , Thakur Jagdish S. , Auner Gregory W.
Published: March 2005

Ablation threshold for single-crystal AlN semiconductor films grown epitaxially on sapphire substrate using indigenously built hollow cathode plasma deposition source molecular-beam epitaxy technique is investigated for a number of pulses by varying the fluence value of each pulse. Using a KrF excimer laser (λ=248nm and τ=25ns) as a radiation source, we found that ablation of AlN thin films is a discontinuous process and its onset requires a minimum threshold fluence ≈1.59J∕cm2. The ablation depth is analyzed for different numbers of pulses and for each number as a function of increasing fluence values. The results show that the ablation depth increases linearly with increasing pulse fluence. It is found that the use of a single pulse for ablation at a given value of fluence is more efficient than a large number of pulses at the same value of fluence/pulse. In addition, we investigated the lowest pulse-fluence limit that can sustain ablation on a disordered AlN film surface. We present a theoretical discussion about the laser energy absorption mechanism and also the rate of energy transfer from the conduction-band electrons to lattice phonons which can lead to the ablation of AlN film. It is found that the rate of energy transfer increases linearly with increasing temperature of the electron gas.
Simulating thermal explosion of cyclotrimethylenetrinitramine-based explosives: Model comparison with experiment
Authors: Yoh Jack J. , McClelland Matthew A. , Maienschein Jon L. , Wardell Jeffrey F. , Tarver Craig M.
Published: March 2005

We compare two-dimensional model results with measurements for the thermal, chemical, and mechanical behavior in a thermal explosion experiment. Confined high explosives (HEs) are heated at a rate of 1°C∕h until an explosion is observed. The heating, ignition, and deflagration phases are modeled using an Arbitrarily Lagrangian-Eulerian code (ALE3D) that can handle a wide range of time scales that vary from a structural to a dynamic hydrotime scale. During the preignition phase, quasistatic mechanics and diffusive thermal transfer from a heat source to the HE are coupled with the finite chemical reactions that include both endothermic and exothermic processes. Once the HE ignites, a hydrodynamic calculation is performed as a burn front propagates through the HE. Two cyclotrimethylenetrinitramine-based explosives, C-4 and PBXN-109, are considered, whose chemical-thermal-mechanical models are constructed based on measurements of thermal and mechanical properties along with small scale thermal explosion measurements. The simulated dynamic response of HE confinement during the explosive phase is compared to measurements in larger scale thermal explosion tests. The explosion temperatures for both HEs are predicted to within 5°C. Calculated and measured wall strains provide an indication of vessel pressurization during the heating phase and violence during the explosive phase. During the heating phase, simulated wall strains provide only an approximate representation of measured values indicating a better numerical treatment is needed to provide accurate results. The results also show that more numerical accuracy is needed for vessels with lesser confinement strength. For PBXN-109, the measured wall strains during the explosion are well represented by the ALE3D calculations.
Length dependent folding kinetics of phenylacetylene oligomers: Structural characterization of a kinetic trap
Authors: Elmer Sidney P. , Pande Vijay S.
Published: March 2005

Using simulation to study the folding kinetics of 20-mer poly-phenylacetylene (pPA) oligomers, we find a long time scale trapped kinetic phase in the cumulative folding time distribution. This is demonstrated using molecular dynamics to simulate an ensemble of over 100 folding trajectories. The simulation data are fit to a four-state kinetic model which includes the typical folded and unfolded states, along with an intermediate state, and most surprisingly, a kinetically trapped state. Topologically diverse conformations reminiscent of α helices, β turns, and sheets in proteins are observed, along with unique structures in the form of knots. The nonhelical conformations are implicated, on the basis of structural correlations to kinetic parameters, to contribute to the trapped kinetic behavior. The strong solvophobic forces which mediate the folding process and produce a stable helical folded state also serve to overstabilize the nonhelical conformations, ultimately trapping them. From our simulations, the folding time is predicted to be on the order of 2.5–12.5 μs in the presence of the trapped kinetic phase. The folding mechanism for these 20-mer chains is compared with the previously reported folding mechanism for the pPA 12-mer chains. A linear scaling relationship between the chain length and the mean first passage time is predicted in the absence of the trapped kinetic phase. We discuss the major implications of this discovery in the design of self-assembling nanostructures.
Energy fluxes and shell-to-shell transfers in three-dimensional decaying magnetohydrodynamic turbulence
Authors: Debliquy Olivier , Verma Mahendra K. , Carati Daniele
Published: March 2005

A spectral analysis of the energy cascade in magnetohydrodynamics (MHD) is presented using high-resolution direct numerical simulation of decaying isotropic turbulence. The Fourier representations of both the velocity and the magnetic fields are split into subsets that correspond to shells of wave vectors. A detailed study of the shell-to-shell interactions is performed and a comparison with theoretical prediction based on field-theoretic method is proposed. Two different definitions for the forward and backward energy transfers are suggested. They provide diagnostics that can be used in order to assess subgrid-scale modeling in large eddy simulation for turbulent MHD systems.
Structure and stability of Al13H clusters
Authors: Han Young-Kyu , Jung Jaehoon , Kim Kyoung Hoon
Published: March 2005

We have performed calculations on the structures and stabilities of Al13H at the density functional and coupled-cluster levels of theory. There are low-symmetry (Cs on-top) isomers energetically comparable to well-known high-symmetry (C2ν bridge and C3ν hollow) isomers. The shape of the Al13 moieties in the Cs isomers is significantly distorted from icosahedral, and similar to Al13 cationic structures. Despite the high stability of the Al13H cluster, Al13H appears to be highly fluxional, as evidenced by multiple close-lying structures.
Electronic Raman spectroscopy of the vanadium(III) hexaaqua cation in guanidinium vanadium sulphate: Quintessential manifestation of the dynamical Jahn–Teller effect
Authors: Carver Graham , Spichiger David , Tregenna-Piggott Philip L. W.
Published: March 2005

Single-crystal Raman spectra are presented for the salt [C(NH2)3][V(OH2)6](SO4)2, displaying electronic transitions between the trigonal components of the vanadium(III) T1g3(Oh) ground term. The A3→E3(C3) electronic Raman band is centered at ∼2720cm−1, and exhibits extensive structure, revealing the energies of the spinor components of the E3(C3) term for the two crystallographically distinct [V(OH2)6]3+ cations. The data are interpreted in conjunction with parameters previously reported from an electron paramagnetic resonance study of the salt. A satisfactory reproduction of the electronic Raman profile and ground-state spin-Hamiltonian parameters is achieved by employing a (A3⊕E3)⊗e vibronic coupling model, in which the spin–orbit splitting of the E3(C3) is quenched significantly by the Ham effect, and the intensity of harmonics of the Jahn–Teller active vibration enhanced by their proximity to the electronic Raman bands. The model gives an excellent account of the intensities of the electronic Raman bands, which are shown to depend profoundly on both temperature and the selected component of the polarizability tensor. The electronic Raman profile changes notably upon deuteriation, a result that exposes deficiencies in the single-mode coupling model.
Direct calculation of solid-liquid equilibria from density-of-states Monte Carlo simulations
Authors: Mastny Ethan A. , de Pablo Juan J.
Published: March 2005

A density-of-states Monte Carlo method is proposed for simulations of solid-liquid phase equilibria. A modified Wang–Landau density-of-states sampling approach is used to perform a random walk in regions of potential energy and volume relevant to solid-liquid equilibrium. The method provides a direct estimate of the relative density of states [Ω(U,V)] and thus the relative free energy within these regions, which is subsequently used to determine portions of the melting curve over wide ranges of pressure and temperature. The validity and usefulness of the method are demonstrated by performing crystallization simulations for the Lennard-Jones fluid and for NaCl.
Probability current in protein electron transfer reactions: A Green function pathway model
Authors: de Andrade Paulo C. P.
Published: March 2005

In a biological electron transfer reaction problem we have found distinct electron probability current representations of macromolecular currents, amino acid and interamino acid currents, atomic and interatomic currents. We present a general interatomic current approach to obtain the electron probability current from donor to acceptor sites, and vice versa. Symmetric (or antisymmetric) renormalizable interatomic currents provide exact (or approximate) effective tunneling matrix element between donor and acceptor states. The electron probability currents allow us to investigate stationary tunneling pathways through protein bridge medium, from molecular to subatomic resolution at any level of electronic description of the biological structure. Analytical comparison among interatomic pathway models is presented and we found equivalent interatomic current representations with distinct dependence on the tunneling energy from the weak to strong coupling between protein bridge and the donor∕acceptor sites.
Accurate quantum calculation of the bound and resonant rovibrational states of Li−(H2)
Authors: Xiao Yingsheng , Poirier Bill
Published: March 2005

In a recent paper [B. Poirier, Chem. Phys. 308, 305 (2005)] a full-dimensional quantum method for computing the rovibrational dynamics of triatomic systems was presented, incorporating three key features: (1) exact analytical treatment of Coriolis coupling, (2) three-body “effective potential,” and (3) a single bend angle basis for all rotational states. In this paper, these ideas are applied to the Li−(H2) electrostatic complex, to compute all of the rovibrational bound state energies, and a number of resonance energies and widths, to very high accuracy (thousandths of a wave number). This application is very challenging, owing to the long-range nature of the interaction and to narrow level spacings near dissociation. Nevertheless, by combining the present method with a G4 symmetry-adapted phase-space-optimized representation, only modest basis sizes are required for which the matrices are amenable to direct diagonalization. Several new bound levels are reported, as compared with a previous calculation [D. T. Chang, G. Surratt, G. Ristroff, and G. I. Gellene, J. Chem. Phys. 116, 9188 (2002)]. The resonances exhibit a clear-cut separation into shape and Feshbach varieties, with the latter characterized by extremely long lifetimes (microseconds or longer).
On the structure of aqueous LiCl solutions
Authors: Harsányi I. , Pusztai L.
Published: March 2005

The structure of highly concentrated aqueous lithium chloride solutions was investigated by the Reverse Monte Carlo method. Two total structure factors, obtained from neutron and x-ray diffraction experiments, were applied as input information. From the resulting particle configurations, partial pair correlation functions, coordination numbers and cosine distributions of bond angles have been determined. It was found that, in accordance with common-sense expectations, the hydrogen bonded network of water molecules is breaking up continuously as the concentration of the electrolyte increases. The hydration shell of the cations becomes more and more distorted as concentration grows whereas the hydration structure of the anions appears to be nearly invariant. Ion-pairing was not detected even at the highest salt concentration.