bluuebunny/crossref_metadata_2025 huggingface dataset:
Das Abschirmungs-Unterbrechungs-Dilemma im Sportspiel
Authors: Höner Oliver
Published: December 2006

Zusammenfassung. Zentrales Anliegen dieses Beitrags ist es, über das Konzept der kognitiven Orientierungen aus der Rubikontheorie ( Gollwitzer, 1996 ) Probleme des Entscheidungshandelns im Sportspiel theoretisch zu beschreiben, die sich mit dem Abschirmungs-Unterbrechungs-Dilemma der Handlungssteuerung ( Goschke, 1997 ) charakterisieren lassen. Aufbauend auf dem Import des Konzepts der kognitiven Orientierungen in ein Forschungsprogramm “Taktische Entscheidungshandlungen im Sportspiel“ und der Rekonstruktion von Sportspielhandlungen auf Grundlage der “ZART“-Version der Rubikontheorie ( Gerjets, 1995 ) wird eine Laborstudie zum Entscheidungshandeln im Fußball dargestellt, die die Anwendung rubikontheoretischer Aussagen zur Weite der Informationsaufnahmebereitschaft in der abwägenden und planenden Phase des Entscheidungsprozesses mit Hilfe der Eye-Tracking-Methode empirisch überprüft. In einer prozesshaften Betrachtung der fußballtypischen Entscheidungshandlungen zeigt sich neben der größeren Weite der Informationsaufnahmebereitschaft in der abwägenden Phase annahmenkonform, dass die visuelle Informationsaufnahmebereitschaft beim Übergang vom Abwägen zum Planen (nicht-linear) rapide eingeengt wird.
Der Zusammenhang zwischen zeitlicher Aufmerksamkeitsallokation und Lese-Rechtschreibleistungen im frühen Sekundarschulalter
Authors: Heim Sabine , Keil Andreas , Ihssen Niklas
Published: December 2006

Zusammenfassung. Der kompetente Umgang mit Schriftsprache erfordert eine zeitlich flexible Verteilung attentionaler Ressourcen. Wir untersuchten Aspekte zeitlicher Aufmerksamkeit bei 29 Kindern der fünften und sechsten Schulklasse. Aufgabe der Schüler war es, zwei grün dargestellte Zielwörter innerhalb einer schnellen Serie von weißen Distraktorwörtern zu identifizieren. Es zeigte sich, dass eine größere temporale Aufmerksamkeitskapazität für Zielreize mit einem höheren Lesetempo im Zürcher Lesetest und einer besseren Rechtschreibleistung in der Hamburger Schreib-Probe einherging. Eine höhere Geschwindigkeit beim Vorlesen sinnarmer Pseudowörter war dagegen mit einer stärkeren durch einen intermittierenden Störreiz bedingten Leistungseinbuße assoziiert. Keiner der untersuchten Aufmerksamkeitsparameter erzielte einen signifikanten Zusammenhang mit der nonverbalen Performanz im Hamburg-Wechsler-Mosaik-Test. Die Ergebnisse legen nahe, dass das Lesen und Schreiben vertrauten Wortmaterials mehr von einer effizienten Aufmerksamkeitszuweisung auf Zielreize als vom Ausblenden aufgabenirrelevanter Items profitiert. Umgekehrt profitieren primär regelgestützte, kontrollierte Prozesse, wie sie beim Pseudowörter-Lesen erforderlich sind, stärker von der Fokussierung auf einen ersten Zielreiz zu Lasten nachfolgender Ereignisse.
Die Entwicklung des prospektiven Gedächtnisses über die Lebensspanne
Authors: Kliegel Matthias , Jäger Theodor
Published: December 2006

Zusammenfassung. Das prospektive Gedächtnis bezeichnet das Zusammenspiel jener kognitiven Fähigkeiten, die daran beteiligt sind, intendierte Handlungen zu planen und sie später zur adäquaten Gelegenheit selbstständig zu realisieren. In dieser Übersichtsarbeit werden Befunde von Studien erörtert, welche die Entwicklung des prospektiven Erinnerns im Kindes- und Jugendalter und vom jüngeren zum höheren Erwachsenenalter untersuchten. Neben der Identifikation erster konsistenter Trends wird außerdem auf eine paradoxe und bisher noch ungeklärte Befundlage bezüglich des alterskorrelierten Ausführens intendierter Handlungen im Labor und im Alltagsleben hingewiesen. Über die Deskription hinausgehend werden in einem zweiten Teil potenzielle Erklärungsmechanismen der Entwicklung des prospektiven Gedächtnisses über die Lebensspanne identifiziert und kritisch diskutiert.
Ästhetische Praxis mit verhaltensauffälligen Kindern und Jugendlichen an Schulen als Präventionsmaßnahme
Authors: Hampe Ruth , Hegeler Peter
Published: December 2006

Zusammenfassung. Es handelt sich um eine Schulbegleitforschung zur Prävention von verhaltensauffälligen Schülern mittels ästhetisch-gestalterischer Methoden an drei Schultypen. Als Fördernahme für verhaltensauffällige Schüler an Schulen konzipiert, geht es um eine gemeinsame Entwicklung von Kooperationsformen zwischen Schülern, Lehrkräften und Eltern. Über eine Wirksamkeitsstudie sollen positive Veränderungen im Verhalten der Schüler belegt werden. Anhand der Vorstellung des Konzeptes und zweier Fallstudien wird ein Einblick gegeben.
Ergebnisse der Tanztherapie sowie der dynamischen Bewegungsmeditationen in der Psychosomatischen Klinik
Authors: Bosák Chetan Karla , Jack Mary
Published: December 2006

Zusammenfassung. In diesem Artikel werden die Ergebnisse zur Wirkung und Wirkungsweise der Tanztherapie sowie der dynamischen Bewegungsmeditationen anhand der Jahresberichte 1999-2002 der Psychosomatischen Klinik dargestellt (empfundene Hilfe). Das Setting der Klinik und die spezielle Vorgehensweise in der Tanztherapie werden beschrieben. Darüber hinaus werden die Ergebnisse der Patientenbefragung von Teilnehmern von Tanztherapieworkshops in der Klinik erläutert. Die Eintagesworkshops fanden in unregelmässiger Folge von 2002-2004 mit den Patienten der Klinik statt. Die Untersuchungsgruppe umfasste hier N = 85, der Fragebogen 16 Items. Als Ergebnis ergab sich ein Modell zur besonderen Wirkungsweise der Tanztherapie in der Psychosomatik in Bezug auf empfundene Hilfe, sowie Lernerfolge in Bezug auf die Körperwahrnehmung, die Ausdrucksfähigkeit, die Fähigkeit loslassen zu können sowie soziale Kompetenz.
Bewegungsspuren als Mittel zur Evaluation von Musiktherapie
Authors: Hörmann Karl
Published: December 2006

Zusammenfassung. Bedingt durch die “atypischen“ Verhältnisse, die notgedrungen zu einer Reduktion von Musiktherapie auf eine sonderliche Art von Musikpsychotherapie geführt haben, wird vielfach psychoanalytisch gedeutet, obgleich außerhalb der Therapiestunden das “Reden über“ so gut wie nie zur Beschäftigung mit Musik veranlasst. Musik und Musizieren verdienen als intrinsische Motivation verstanden zu werden. Die hier vorgestellten Studien haben wieder einmal gezeigt, dass Musikstücke wie Menschen behandelt werden können. Sie lassen sich mit Hilfe von Persönlichkeitstests charakterisieren, und Persönlichkeitsfaktoren können musikalisch für jedermann verständlich dargestellt werden. Mehr als Assoziationen und das Deuten von Befindlichkeitszuständen führt das bewusste Erleben und mit- und nachvollziehende Gestalten von intra- und interpersonalen wie auch musikalischen Bewegungsspuren und die Erfahrung ihrer vielschichtigen Wirkungsmöglichkeiten zwischen Schlichtheit und Komplexität zu einer Effizienz, Effektivität und Wirtschaftlichkeit ermöglichenden Diagnostik und Evaluation.
A new 1649–1884 catalog of destructive earthquakes near Tokyo and implications for the long‐term seismic process
Authors: Grunewald Elliot D. , Stein Ross S.
Published: December 2006

In order to assess the long‐term character of seismicity near Tokyo, we construct an intensity‐based catalog of damaging earthquakes that struck the greater Tokyo area between 1649 and 1884. Models for 15 historical earthquakes are developed using calibrated intensity attenuation relations that quantitatively convey uncertainties in event location and magnitude, as well as their covariance. The historical catalog is most likely complete for earthquakes M ≥ 6.7; the largest earthquake in the catalog is the 1703 M ∼ 8.2 Genroku event. Seismicity rates from 80 years of instrumental records, which include the 1923 M = 7.9 Kanto shock, as well as interevent times estimated from the past ∼7000 years of paleoseismic data, are combined with the historical catalog to define a frequency‐magnitude distribution for 4.5 ≤ M ≤ 8.2, which is well described by a truncated Gutenberg‐Richter relation with a b value of 0.96 and a maximum magnitude of 8.4. Large uncertainties associated with the intensity‐based catalog are propagated by a Monte Carlo simulation to estimations of the scalar moment rate. The resulting best estimate of moment rate during 1649–2003 is 1.35 × 1026 dyn cm yr−1 with considerable uncertainty at the 1σ level: (−0.11, + 0.20) × 1026 dyn cm yr−1. Comparison with geodetic models of the interseismic deformation indicates that the geodetic moment accumulation and likely moment release rate are roughly balanced over the catalog period. This balance suggests that the extended catalog is representative of long‐term seismic processes near Tokyo and so can be used to assess earthquake probabilities. The resulting Poisson (or time‐averaged) 30‐year probability for M ≥ 7.9 earthquakes is 7–11%.
Signatures of stratosphere to troposphere transport near deep convective events in the southern subtropics
Authors: Leclair De Bellevue J. , Réchou A. , Baray J. L. , Ancellet G. , Diab R. D.
Published: December 2006

A climatology of tropospheric ozone profiles associated with tropical convection in the southwestern part of the Indian Ocean and over South Africa is presented. Then case studies of stratospheric‐tropospheric exchange are documented using radiosoundings, ozone lidar, satellite and ECMWF global model data. In three distinct cases of varying tropical convection intensity (depression and cyclone Guillaume near Reunion in February 2002 and convection near Irene in November 2000), strong interaction between convection‐induced upper level circulation, jet front systems and Rossby Wave Breaking induces stratosphere to troposphere exchanges. Stratospheric filaments in the upper troposphere evident in the ECMWF analyses are in good agreement with ozone, humidity and temperature vertical profile observations. For the Guillaume case study near Reunion, filaments and subsidence occur in both cases (depression on 15 February and cyclone on 19 February 2002). On 15 February, a moderate enhancement of ozone in the free troposphere is observed and on 19 February, a 100 ppbv ozone peak is recorded. In the Irene case study, a large upper level depression coming from the stratosphere, fed by a filament wrapped around the convective area in the Mozambican channel, induces an ozone peak of larger magnitude (170 ppbv). Secondary ozone sources (jet front system in the Atlantic and biomass burning in South America) could further amplify this ozone enhancement. The radiosounding indicates a strong ozone enhancement in the upper troposphere, without a signature of pumping from the lower layers, in contrast to the Guillaume case.
Reactive uptake of pinonaldehyde on acidic aerosols
Authors: Liggio John , Li Shao‐Meng
Published: December 2006

The reactive uptake of pinonaldehyde, a monoterpene oxidation product, on aerosols has been studied in a reaction chamber. Monodisperse inorganic seed aerosols, consisting of acidic mixtures of (NH4)2SO4 and H2SO4, were exposed to gaseous pinonaldehyde for several hours within the chamber under relative humidity conditions of 3–65%. The aerosol inorganic and organic mass were quantitatively monitored in real time with an aerosol mass spectrometer (AMS) which also measured the mass spectra of the aerosols. Numerous fragments in the mass spectra were observed with masses greater than what can be accounted for by pinonaldehyde alone and have arisen from oligomerization in reactive uptake processes. The evolution of the mass spectra also revealed a progression toward larger oligomers over time. Significant organic mass was added to the aerosols in most experiments immediately upon exposure, resulting in maximum organic mass loadings from 3.5–110 μgm−3 depending on the experiments. Organic mass to seed aerosol SO4= ratios were also highly variable (0.06–4.75), resulting in particles ranging in composition from primarily inorganic to mostly organic. This reactive uptake was highly dependent upon the aerosol water activity, and hence acidity and did not occur on neutral (NH4)2SO4 aerosols suggesting that acidity is necessary. Reactive uptake coefficients (γ) of pinonaldehyde were calculated by fitting a model of organic mass growth to the data. The coefficients spanned two orders of magnitude (1.2 × 10−5–1.3 × 10−3) and were primarily dependent upon aerosol water activity and acidity but independent of gas phase pinonaldehyde concentrations. These coefficients indicated that the heterogeneous reactions of pinonaldehyde are of little importance as a gas phase loss mechanism but potentially of major importance as a source of secondary organic aerosols (SOA). Estimates of SOA production via pinonaldehyde, using the derived γ, suggest that 1–750 ng m−3 of organic material can be formed in a short time, consistent with ambient measurements.
Diversity and distribution of subseafloor Thermococcales populations in diffuse hydrothermal vents at an active deep‐sea volcano in the northeast Pacific Ocean
Authors: Huber Julie A. , Butterfield David A. , Baross John A.
Published: December 2006

The presence, diversity, and distribution of a key group of subseafloor archaea, the Thermococcales, was examined in multiple diffuse flow hydrothermal vents at Axial Seamount, an active deep‐sea volcano located in the northeast Pacific Ocean. A polymerase chain reaction (PCR) approach was used to determine if this group of subseafloor indicator organisms showed any phylogenetic distribution that may indicate distinct subseafloor communities at vents with different physical and chemical characteristics. Targeted primers for the Thermococcales 16S rRNA (small subunit ribosomal RNA) gene and intergenic transcribed spacer (ITS) region were designed and applied to organisms filtered directly from a variety of diffuse flow vents. Thermococcales were amplified from 9 of 11 samples examined, and it was determined that the ITS region is a better phylogenetic marker than the 16S rRNA in defining consistent groups of closely related sequences. Results show a relationship between environmental clone distribution and source vent chemistry. The most highly diluted vents with elevated iron and alkalinity contained a distinct group of Thermococcales as defined by the ITS region, suggesting separate subseafloor Thermococcales populations at diffuse vents within the Axial caldera.
Active tectonics of the Turkish‐Iranian Plateau
Authors: Copley Alex , Jackson James
Published: December 2006

This paper examines how active faulting in the Turkey‐Iran‐Caucasus region accommodates the Arabia‐Eurasia collision and the velocity field observed by GPS. The overall shortening across the zone is, in general, spatially separated (“partitioned”) into right‐lateral strike slip in the Turkish‐Iranian Plateau and thrusting in the Greater Caucasus. A band of counterclockwise rotating NW‐SE right‐lateral strike‐slip faults accommodates a NW‐SE gradient in NE directed velocity (relative to Eurasia) between the Black and Caspian seas. A NNW‐SSE band of previously unrecognized oblique normal faults is present on the Turkey‐Iran border. We estimate the offsets on faults from geomorphological features and show that these offsets can be achieved in 5 ± 2 Ma at present rates. This implies a reorganization of deformation in the collision zone at that time, after the initial collision at ∼12 Ma, probably in response to mantle‐induced dynamic uplift.
Impact of the Atlantic Multidecadal Oscillation on the Asian summer monsoon
Authors: Lu Riyu , Dong Buwen , Ding Hui
Published: December 2006

The impact of the Atlantic Multidecadal Oscillation (AMO) on the Asian summer monsoon is investigated using a coupled atmosphere‐ocean global general circulation model by imposing the AMO‐associated sea surface temperature anomalies in the Atlantic as boundary forcing, and allowing atmosphere‐ocean interactions outside the Atlantic. The positive AMO phase, characterized by anomalous warm North Atlantic and cold South Atlantic, leads to strong Southeast and east Asian summer monsoons, and late withdrawal of the Indian summer monsoon. These changes of monsoons are mainly through coupled atmosphere‐ocean feedbacks in the western Pacific and Indian Oceans and tropospheric temperature changes over Eurasia in response to the imposed forcing in the Atlantic. The results are in agreement with the observed climate changes in China corresponded to the AMO phases. They suggest a non‐local mechanism for the Asian summer monsoon variability and provide an alternative view to understanding its interdecadal variation during the twentieth century.
Potential use of microwave sea surface temperatures for the estimation of ocean currents
Authors: Isern‐Fontanet J. , Chapron B. , Lapeyre G. , Klein P.
Published: December 2006

In this paper, we examine the emerging potential offered by satellite microwave radiometer SST measurements to complement altimeter data to quantitatively derive surface ocean currents. The proposed methodology does not follow standard sequential temporal analysis but follows the application of the Surface Quasi‐Geostrophic (SQG) theory. Accordingly, under favourable environmental conditions, the implementation for this methodology is simple and robust, and most importantly, solely requires a single SST image. For the present demonstration, altimetric measurements are used to infer a necessary adjustment to match the kinetic energy level for length scales smaller than 300 km. This helps to derive a regional effective Brunt‐Väisälä frequency to produce SQG surface current estimates. As demonstrated, the results are very encouraging and strongly invite to consider the systematic use of satellite microwave radiometer measurements.
Nonlinear statistics reveals stronger ties between ENSO and the tropical hydrological cycle
Authors: Khan Shiraj , Ganguly Auroop R. , Bandyopadhyay Sharba , Saigal Sunil , Erickson David J. , Protopopescu Vladimir , Ostrouchov George
Published: December 2006

Cross‐spectrum analysis based on linear correlations in the time domain suggested a coupling between large river flows and the El Niño‐Southern Oscillation (ENSO) cycle. A nonlinear measure based on mutual information (MI) reveals extrabasinal connections between ENSO and river flows in the tropics and subtropics, that are 20–70% higher than those suggested so far by linear correlations. The enhanced dependence observed for the Nile, Amazon, Congo, Paraná, and Ganges rivers, which affect large, densely populated regions of the world, has significant impacts on inter‐annual river flow predictabilities and, hence, on water resources and agricultural planning.
Hot and cool summers: Multiple equilibria of the continental water cycle
Authors: D'Andrea Fabio , Provenzale Antonello , Vautard Robert , De Noblet‐Decoudré Nathalie
Published: December 2006

Large variations in soil water reserves and surface temperature over the continents are linked to a positive feedback between precipitation and soil moisture. This mechanism can generate bimodal distributions of soil moisture. Here, we show that bimodality results from the existence of multiple equilibria in the continental water balance, considering the coupled system including the upper soil layer and the atmospheric planetary boundary layer. This mechanism is described with an idealized box model, that includes convergence and divergence of moisture fluxes, convection, precipitation and evapotranspiration. The existence of two equilibria is associated with the variation of precipitation efficiency, which depends on convection intensity. The two regimes correspond to realistic values of climatic variables associated with mean wet or dry summers, and can persist for the whole summer season when forced by a stochastic moisture convergence flux. This suggests that a key role for midlatitude continental summer climate is played by the continental soil water content.
Gas isotopes in ice reveal a vegetated central Greenland during ice sheet invasion
Authors: Souchez R. , Jouzel J. , Landais A. , Chappellaz J. , Lorrain R. , Tison J.‐L.
Published: December 2006

Environmental conditions prevailing during build‐up of the Greenland Ice Sheet (GIS) are not yet established. Here we use results from gas isotopes from basal ice of the GRIP ice core to show that central Greenland was vegetated during invasion by the ice sheet. The δ13CCH4 and δ18O of O2 values obtained were never encountered before in ice core studies. Such values are indeed the signature of a significant biological activity.
A three‐dimensional model of the generalized polar wind
Authors: Barakat Abdallah R. , Schunk Robert W.
Published: December 2006

The dynamic behavior of the “generalized” polar wind is investigated using a three‐dimensional (3‐D) dynamic model. The model is composed of two components. The high‐altitude component is based on a macroscopic particle‐in‐cell (mac‐PIC) approach that extends from an altitude of 1200 km to several Earth radii. The lower boundary conditions of the mac‐PIC model are provided by a 3‐D fluid‐like model (low‐altitude component) that extends down to 100 km in altitude. With the coupled model, the relevant equations are solved along magnetic flux tubes that convect across the high‐latitude region. A large number (∼1000) of plasma flux tubes are followed. The total number of simulation particles in the mac‐PIC component is 108–109. The generalized polar wind is simulated for an idealized geomagnetic storm, with a time step of 2.5 s. The model properly accounts for many physical mechanisms such as ion‐ion collisions, wave‐particle interactions, magnetospheric energetic electrons, and low‐altitude ion energization. The computing‐intensive nature of the model requires utilization of supercomputers with thousands of processors. A 3‐D picture is assembled from the temporal evolution of the individual flux tubes by keeping track of their locations. The resulting 3‐D dynamic picture is investigated with special emphasis on the difference between the behaviors of the O+ and H+ ions. The main conclusions are as follows: (1) during the storm maximum phase, O+ may remain dominant for altitudes up to several Earth radii; (2) the O+‐to‐H+ density velocity and flux ratios tend to be greatly enhanced during the storm with time delays of 0.5 to 1 hour; (3) the O+ downward flow tends to occur in the subauroral region and the dawnside of the polar cap; and (4) the O+ downward flux in the polar cap tends to occur below 1 RE altitude and during the storm decay phase.
Repetitive substorms caused by Alfvénic waves of the interplanetary magnetic field during high‐speed solar wind streams
Authors: Lee D.‐Y. , Lyons L. R. , Kim K. C. , Baek J.‐H. , Kim K.‐H. , Kim H.‐J. , Weygand J. , Moon Y.‐J. , Cho K.‐S. , Park Y. D. , Han W.
Published: December 2006

Substorms sometimes occur repetitively with a period of ∼1–4 hours. In this paper we examine repetitive substorms, identified using particle injections and positive H bays on the nightside, that we find to occur during corotating high‐speed streams associated with coronal holes. The high‐speed streams often last for several days and are accompanied by large amplitude Alfvén waves of the interplanetary magnetic field (IMF). We find that repetitive substorms occur every ∼1–4 hours, regardless of the solar cycle phase, whenever the Earth's magnetosphere is impinged by these high‐speed streams. We further find that a significant number of these substorms are associated with repetitive northward turnings of the Alfvénic IMF, each northward turning preceded by weakly‐to‐moderately southward IMF, i.e., Bz ∼ −3.6 nT for ∼29 min on the average. We present eight example intervals where most of the repetitive substorms were associated with a northward turning. Statistically, for 63.5% of 312 substorms we are able to identify a reasonable association with a northward turning. While limitations of the Weimer‐mapped IMF used here and the spatial structure of the Alfvénic IMF prevent us from estimating a precise figure for the percentage of IMF triggered substorms, our results indicate that many of the repetitive substorms are likely due to repetitive triggering by the Alfvénic IMF.
Alfvén wave filamentation and particle acceleration in solar wind and magnetosphere
Authors: Sharma R. P. , Singh H. D. , Malik M.
Published: December 2006

We present numerical simulations of Alfvén waves in steady state, leading to the formation of intense magnetic filaments when the nonlinearity arises due to the ponderomotive effects and Joule heating. When the plain Alfvén wave is perturbed by a transverse perturbation and the magnitude of the pump Alfvén wave changes, chaotic filamentary structures of magnetic field in kinetic Alfvén wave (KAW) filamentation and quasiperiodic in inertial Alfvén wave (IAW) filamentation have been observed. At higher KAW pump wave amplitude, the spectra approaches near the Kolmogorov k−5/3 scaling. The spectral index becomes k−3 scaling in IAW. Relevance of these studies in solar wind and magnetosphere for KAW and solar corona and auroral region for IAW has also been pointed out. Particle heating in these small‐scale filamentary structures has also been calculated by using velocity space diffusion coefficient in Fokker‐Planck equation.
Meteor trail diffusion and fields: 1. Simulations
Authors: Dimant Y. S. , Oppenheim M. M.
Published: December 2006

A meteoroid penetrating the Earth's atmosphere leaves behind a trail of dense plasma embedded in the lower E/upper D region ionosphere. While radar measurements of meteor trail evolution have been collected and used to infer meteor and atmospheric properties since the 1950s, no accurate quantitative model of trail fields and diffusion exists. This paper describes finite element simulations of trail plasma physics applicable to the majority of small meteors. Unlike earlier research, our simulations resolve both the trail and a vast current closure area in the background ionosphere. This paper also summarizes a newly developed analytical theory of meteor electrodynamics and shows that our simulations and theory predict nearly identical fields and diffusion rates. This study should enable meteor and atmospheric researchers to more accurately interpret radar observations of specular and nonspecular meteor echoes.
Magnetic cloud distortion resulting from propagation through a structured solar wind: Models and observations
Authors: Owens M. J.
Published: December 2006

Numerical simulations of magnetic clouds (MCs) propagating through a structured solar wind suggest that MC‐associated magnetic flux ropes are highly distorted by inhomogeneities in the ambient medium. In particular, a solar wind configuration of fast wind from high latitudes and slow wind at low latitudes, common at periods close to solar minimum, should distort the cross section of magnetic clouds into concave‐outward structures. This phenomenon has been reported in observations of shock front orientations, but not in the body of magnetic clouds. In this study an analytical magnetic cloud model based upon a kinematically distorted flux rope is modified to simulate propagation through a structured medium. This new model is then used to identify specific time series signatures of the resulting concave‐outward flux ropes. In situ observations of three well studied magnetic clouds are examined with comparison to the model, but the expected concave‐outward signatures are not present. Indeed, the observations are better described by the convex‐outward flux rope model. This may be due to a sharp latitudinal transition from fast to slow wind, resulting in a globally concave‐outward flux rope, but with convex‐outward signatures on a local scale.
Simulation of the POLAR‐observed Geomagnetic Ion Energy Spectrometer
Authors: Zeng W. , Horwitz J. L. , Elliott H. A. , Moore T. E.
Published: December 2006

Observations by polar‐orbiting spacecraft of outward streaming ionospheric O+ ions in the polar cap magnetosphere often show decreasing field‐aligned streaming energy with antisunward distance from their apparent dayside source, the Cleft Ion Fountain (CIF). In this paper we use the UT Arlington Dynamic Fluid‐Kinetic (DyFK) ionospheric plasma transport model to simulate the transport of CIF generated ions along convecting magnetic flux tubes. We compare these simulations to observations by the Thermal Ion Dynamics Experiments (TIDE) on board the Polar spacecraft, for periods when the Polar orbit was aligned parallel to the noon‐midnight direction. When the Polar spacecraft traversed from high altitudes on the dayside to lower altitudes on the nightside, the peak O+ streaming energy decreased from above 100 eV to below 5 eV. For the case in which the Polar satellite traveled from the nightside higher altitude to the dayside lower altitude, the O+ energy remained relatively stable, ranging between 20 eV and about 50 eV. Using the DyFK model, we simulate the ionospheric plasma transport and, in particular, the energy spectrometer effects under the geophysical circumstances of the observations, and compare the simulated and observed streaming energies. The results show that the simulated O+‐streaming energy variations in the noon‐midnight direction were in reasonable agreement with those of the Polar/TIDE observations, independent of whether Polar was moving sunward or antisunward, for realistic choices of geophysical parameters. The altitude and the distance to the CIF are the two primary O+ parameters influencing the O+ energy spectrometer variations, with the antisunward distance from the CIF being the principal controlling parameter.
One‐dimensional hybrid simulations of planetary ion pickup: Techniques and verification
Authors: Cowee M. M. , Strangeway R. J. , Russell C. T. , Winske D.
Published: December 2006

Previously, hybrid simulation techniques using massless fluid electrons and kinetic ions have been successfully applied to study the electromagnetic plasma waves generated by ion pickup in the solar wind, where instability is driven by the large drift velocities of newborn ion populations. For ion pickup at Jupiter and Saturn's magnetospheres where instability is driven by heavy ions with a ring velocity distribution, we show that the one‐dimensional hybrid simulation technique can successfully reproduce the behavior of this instability as predicted by linear dispersion theory as well as the important nonlinear wave‐particle interactions. The simulated ion cyclotron waves have frequencies near the ion gyrofrequency and are generated as the anisotropic newborn ion ring distribution scatters to a more isotropic configuration. Simulated maximum wave amplitudes and instability growth rates increase with newborn ion density and pickup velocity. For appropriate heavy pickup ion densities and velocities the simulated wave amplitudes are within the range observed by spacecraft.
Tracing deep‐sea calcite dissolution: Agreement between the Globorotalia menardii fragmentation index and elemental ratios (Mg/Ca and Mg/Sr) in planktonic foraminifers
Authors: Mekik Figen , François Roger
Published: December 2006

Accurately quantifying deep‐sea calcite dissolution is crucial for understanding the role of the marine carbonate system in regulating atmospheric pCO2 over millennia. We compare a foraminifer‐fragmentation‐based calcite dissolution proxy (Globorotalia menardii fragmentation index (MFI)) to Mg/Ca, Sr/Ca, and Mg/Sr in several species of deep dwelling planktonic foraminifers. We conducted microfossil and geochemical analyses on the same core top samples taken at different depths on the Ontong Java Plateau to maximize the dissolution signal and minimize the temperature overprint on our data. We also compare elemental ratios from planktonic foraminifer tests to modern bottom water CO3= undersaturation and model‐derived estimates of percent calcite dissolved in deep‐sea sediments. We find clear linear decreases in Mg/Ca or Mg/Sr in G. menardii and Pulleniatina obliquiloculata with increasing (1) bottom water CO3= undersaturation, (2) percent calcite dissolved in sediments calculated with biogeochemical modeling, (3) MFI, and (4) percent calcite dissolved derived from MFI. These findings lend further support to MFI as a calcite dissolution proxy for deep‐sea sediments. In contrast, we find no significant correlation between Sr/Ca and independent dissolution indicators. Our results suggest that Mg/Ca and Mg/Sr from deep dwelling foraminifers could potentially be used as calcite dissolution proxies in combination with independent water temperature estimates. Likewise, establishing the relationship between MFI and dissolution‐induced changes in the Mg/Ca of surface‐dwelling foraminifers could provide a tool to correct Mg/Ca–derived sea surface temperature reconstructions for calcite dissolution.
Methods for colloid transport visualization in pore networks
Authors: Ochiai Naoyuki , Kraft Erika L. , Selker John S.
Published: December 2006

Prediction of colloid transport in the subsurface is relevant to researchers in a variety of fields such as contaminant transport, wastewater treatment, and bioremediation. Investigations have traditionally relied on column studies whereby mechanistic inferences must be drawn on the basis of colloid behavior at the outlet. Over the past decade, development of noninvasive visualization techniques based on visible light, magnetic resonance, and X rays have provided insight into a number of colloid transport mechanisms by enabling direct observation of individual colloids at the pore scale and colloid concentrations at longer length scales. As research focus shifts from transport of ideal colloids in ideal media such as glass beads to natural colloids in natural porous media, these noninvasive techniques will become increasingly useful for studying the collection of mechanisms at work in heterogeneous pore systems. It is useful at this juncture to review recent progress in colloid transport visualization as a starting point for further development of visualization tools to support investigation of colloids in natural systems. We briefly discuss characteristics of visualization systems currently used to study colloid transport in porous media and review representative microscale and mesoscale visualization studies conducted over the past decade, with additional attention given to two optical visualization systems being developed by the authors.
SLC41A2 encodes a plasma-membrane Mg2+ transporter
Authors: Sahni Jaya , Nelson Bruce , Scharenberg Andrew M.
Published: January 2007

The TRPM7 (transient receptor potential melastatin 7) ion channel has been implicated in the uptake of Mg2+ into vertebrate cells, as elimination of TRPM7 expression through gene targeting in DT40 B-lymphocytes renders them unable to grow in the absence of supplemental Mg2+. However, a residual capacity of TRPM7-deficient cells to accumulate Mg2+ and proliferate when provided with supplemental Mg2+ suggests the existence of Mg2+ uptake mechanism(s) other than TRPM7. Evaluation of the expression of several members of the SLC41 (solute carrier family 41) family, which exhibit homology with the MgtE class of prokaryotic putative bivalent-cation transporters, demonstrated that one, SLC41A2 (solute carrier family 41 member 2), is expressed in both wild-type and TRPM7-deficient DT40 cells. Characterization of heterologously expressed SLC41A2 protein indicated that it is a plasma-membrane protein with an N-terminus-outside/C-terminus-inside 11-TM (transmembrane)-span topology, consistent with its functioning as a trans-plasma-membrane transporter. In contrast with a previous report of ion-channel activity associated with SLC41A2 expression in oocytes, investigation of whole cell currents in SLC41A2-expressing DT40 cells revealed no novel currents of any type associated with SLC41A2 expression. However, expression of SLC41A2 in TRPM7-deficient cells under the control of a doxycycline-inducible promoter was able to conditionally enhance their net uptake of 26Mg2+ and conditionally and dose-dependently provide them with the capacity to grow in the absence of supplemental Mg2+, observations strongly supporting a model whereby SLC41A2 directly mediates trans-plasma-membrane Mg2+ transport. Overall, our results suggest that SLC41A2 functions as a plasma-membrane Mg2+ transporter in vertebrate cells.
Influence of substitutional metallic impurities on the performances of p-type crystalline silicon solar cells: The case of gold
Authors: Dubois S. , Palais O. , Pasquinelli M. , Martinuzzi S. , Jaussaud C.
Published: December 2006

The influence of a gold bulk contamination on the performances of boron doped p-type crystalline silicon solar cells is investigated for different base doping levels and different kinds of materials, such as float zone Si, Czochralski Si, and multicrystalline Si. Solar cells are made from intentionally contaminated silicon wafers. By monitoring the evolution of the electrically active substitutional gold concentration by means of bulk lifetime and minority carrier diffusion length measurements, this paper highlights the eventual gettering or hydrogenation effects occurring throughout the whole process but also of the danger of such an impurity in materials containing large densities of extended defects generating recombination centers by means of the impurity-defect interaction.
Raman scattering studies of Te doped In0.14Ga0.86As0.13Sb0.87 alloys grown on GaSb by liquid phase epitaxy
Authors: Díaz-Reyes J. , López-Cruz E. , Mendoza-Álvarez J. G. , Jiménez-Sandoval S.
Published: December 2006

Using the liquid phase epitaxy technique under supercooling conditions we have grown In0.14Ga0.86As0.13Sb0.87 layers doped with tellurium lattice-matched to (100) n-GaSb. Layers doped with Te were accomplished by incorporating Sb2Te3 pellets into the growth melt in the range from 6.48×10−6M to 4.31×10−4M. Using Raman spectroscopy we characterized the structural quality. Two main bands are observed in the Raman spectra centered at 230 and 245cm−1 which depend strongly on the molar concentration of Sb2Te3. The assignation of the observed vibrational modes to GaAs-like and to (GaSb+InAs)-like mixture modes is discussed using the random-element isodisplacement (REI) model. The REI model seems to describe the observed behavior of vibrational modes reasonably.
Optimization of finite diffraction gratings for the excitation of surface plasmons
Authors: Lévêque Gaëtan , Martin Olivier J. F.
Published: December 2006

The excitation of a surface plasmon polariton (SPP) wave on a metal-air interface by a diffraction grating under monochromatic normal illumination is investigated numerically. The influence of the different experimental parameters (grating thickness, period, and duty cycle) is discussed in detail for a semi-infinite metal and a thin film. Both engraved (grooves) and deposited (protrusions) gratings are considered. The most efficient coupling to the SPP is obtained for a groove grating which duty cycle is about 0.5. Furthermore a small grating depth of some tens of nanometers is sufficient to excite a SPP mode with a coupling efficiency higher than 16% in each direction. Implications for practical SPP experiments are discussed.
Large third-order optical nonlinearity in (Pb,La)(Zr,Ti)O3 ferroelectric thin film
Authors: Leng W. J. , Yang C. R. , Ji H. , Zhang J. H. , Tang J. L. , Chen H. W.
Published: December 2006

Ferroelectric (Pb0.92La0.08)(Zr0.65Ti0.35)O3 (PLZT) film with good surface morphology and perovskite structure was grown in situ on quartz substrate by radio-frequency magnetron sputtering at 650°C. The fundamental optical constants (the band gap energy, linear refractive index, and absorption coefficient) of the film are obtained by optical transmittance measurement. The third-order nonlinear optical properties of the films were investigated by the Z-scan technique. The magnitude and sign of the nonlinear refractive index n2 were determined, as was the negative sign, which indicated a self-defocusing optical nonlinearity. A large nonlinear refractive index as high as 1.21×10−6esu is displayed in the film. All results show that PLZT ferroelectric thin film has potential applications in nonlinear optical devices.
Thermopower and thermal conductivity of the electron-doped manganite La0.9Te0.1MnO3
Authors: Yang J. , Sun Y. P. , Song W. H. , Lee Y. P.
Published: December 2006

The thermal properties and their relationship to the charge transport properties of an electron-doped manganite La0.9Te0.1MnO3 were investigated. The resistivity and the Hall effect were measured. The magnetic-field dependence of Hall resistivity indicates that the carriers in La0.9Te0.1MnO3 are electrons. The thermopower S and thermal conductivity κ were also measured. Above the metal-insulator transition temperature TP, a significant difference between the resistivity activation energy (Eρ=128.3meV) and the thermopower activation energy (ES=14.7meV) was observed, implying that the conductivity of La0.9Te0.1MnO3 above TP was dominated by the small-polaron hopping. In the ferromagnetic region, it is found that S shows T3∕2 dependence, suggesting that the electron-magnon scattering strongly affects the low-temperature thermopower of La0.9Te0.1MnO3. The temperature dependence of thermal conductivity, κ(T), reveals that the phonon component (κph) is the major one. Moreover, in the paramagnetic region, a positive dκ∕dT is observed, i.e., dκ∕dT>0, which might be related to the local anharmonic lattice distortions.
Additional dc magnetic field response of magnetostrictive/piezoelectric magnetoelectric Laminates by Lorentz force effect
Authors: Jia Yanmin , Tang Yanxue , Zhao Xiangyong , Luo Haosu , Or Siu Wing , Chan Helen Lai Wa
Published: December 2006

We have discovered that traditional long-type magnetoelectric laminate composite of magnetostrictive Tb1−xDyxFe2−y and piezoelectric materials possesses additional ability of detecting dc magnetic field, using the product effect of the Lorentz force effect from Terfenol-D metal strips in dc magnetic field applied with an ac electrical current and the piezoelectric effect from piezoelectric material. The output voltage between the two faces of piezoelectric (1−x)Pb(Mg1∕3Nb2∕3)O3–xPbTiO3 single crystal shows a good linear response to applied dc magnetic field of 100–1200Oe under different ac electrical current inputs (0.4–200mA). The magnetoelectric coefficient is about ∼64.1mV∕TA. The additional dc magnetic field response of magnetostrictive/piezoelectric magnetoelectric laminates driven by Lorentz force makes this composite hopeful for application in coil-free ac/dc magnetic-sensitive sensors. At the same time, for this composite, the additional ability will not affect the primal ability for detecting ac magnetic field.
Experimental profile evolution of a high-density field-reversed configuration
Authors: Ruden E. L. , Zhang Shouyin , Intrator T. P. , Wurden G. A.
Published: December 2006

A field-reversed configuration (FRC) gains angular momentum over time, eventually resulting in an n=2 rotational instability (invariant under rotation by π) terminating confinement. To study this, a laser interferometer probes the time history of line integrated plasma density along eight chords of the high-density (∼1017cm−3) field-reversed configuration experiment with a liner. Abel and tomographic inversions provide density profiles during the FRC’s azimuthally symmetric phase, and over a period when the rotational mode has saturated and rotates with a roughly fixed profile, respectively. During the latter part of the symmetric phase, the FRC approximates a magnetohydrodynamic (MHD) equilibrium, allowing the axial magnetic-field profile to be calculated from pressure balance. Basic FRC properties such as temperature and poloidal flux are then inferred. The subsequent two-dimensional n=2 density profiles provide angular momentum information needed to set bounds on prior values of the stability relevant parameter α (rotational to ion diamagnetic drift frequency ratio), in addition to a view of plasma kinematics useful for benchmarking plasma models of higher order than MHD.
Dynamics of photosensitized formation of singlet oxygen by porous silicon in aqueous solution
Authors: Fujii Minoru , Nishimura Naoki , Fumon Hirokazu , Hayashi Shinji , Kovalev Dmitry , Goller Bernhard , Diener Joachim
Published: December 2006

Generation of singlet oxygen due to energy transfer from photoexcited silicon nanocrystals in D2O is demonstrated. It is shown that the singlet oxygen generation efficiency, i.e., the intensity of near-infrared emission from singlet oxygen gradually decreases when Si nanocrystals are continuously irradiated in O2-saturated D2O. The mechanism of the photodegradation of the photosensitizing efficiency is studied using photoluminescence and infrared absorption techniques. Experimental results suggest that the interaction of photogenerated singlet oxygen with the hydrogen-terminated surface of silicon nanocrystals results in photo-oxidation of silicon nanocrystals, and the surface oxides reduce the photosensitizing efficiency. It is also demonstrated that photo-oxidation of porous silicon in O2-saturated water results in a strong enhancement of the photoluminescence quantum yield of porous Si.
Spatial inhomogeneities in Cu(In,Ga)Se2 solar cells analyzed by an electron beam induced voltage technique
Authors: Grabitz Peter O. , Rau Uwe , Wille Bernd , Bilger Gerhard , Werner Juergen H.
Published: December 2006

Spatial variations of the local open circuit voltage in Cu(In,Ga)Se2 solar cells are analyzed by an electron beam induced voltage (EBIV) technique. The major pattern visualized by our EBIV measurements are spatial inhomogeneities on a length scale of between 5 and 20μm. Quantitative evaluation of the EBIV signals shows that the loss of open circuit voltage due to the inhomogeneities is about 100mV. Additional analysis of our samples by energy dispersive x-ray analysis excludes fluctuations of the Ga or Cu content as the source of the inhomogeneities. Instead, the spatial inhomogeneous supply of Na from the glass substrate turns out as a possible origin of inhomogeneities. Spatially resolved secondary ion mass spectroscopy measurements show that the Na content of our Cu(In,Ga)Se2 samples varies between 0.03 and 0.15at.% on a length scale of tens of micrometers.
Magnetic-divertor stabilization of an axisymmetric plasma with anisotropic temperature
Authors: Sasagawa Y. , Katanuma I. , Mizoguchi Y. , Cho T. , Pastukhov V. P.
Published: December 2006

Magnetohydrodynamic stabilization of an axisymmetric mirror plasma with a magnetic divertor is studied. An equation is found for the flute modes, which includes the stabilizing influence of ion temperature anisotropy and nonparaxial magnetic fields, as well as a finite ion Larmor radius. It is shown that if the density profile is sufficiently gentle, then the nonparaxial configuration can stabilize all modes as long as ion temperature is radially uniform. This can be demonstrated even when the density vanishes on the separatrix and even for small ion Larmor radii. It is found, however, that the ion temperature gradient makes the unstable region wider; high ion temperature is required to stabilize the flute mode.
Calibration of a horizontally acting force transducer with the use of a simple pendulum
Authors: Taberner Andrew J. , Hunter Ian W.
Published: December 2006

This article details the implementation of a method for calibrating horizontally measuring force transducers using a pendulum. The technique exploits the sinusoidal inertial force generated by a suspended mass as it pendulates about a point on the measurement axis of the force transducer. The method is used to calibrate a reconfigurable, custom-made force transducer based on exchangeable cantilevers with stiffness ranging from 10to104N∕m. In this implementation, the relative combined standard uncertainty in the calibrated transducer stiffness is 0.41% while the repeatability of the calibration technique is 0.46%.