bluuebunny/crossref_metadata_2025 huggingface dataset:
Starke und schwache Argumente als Teile derselben Botschaft
Authors: Erb Hans-Peter , Büscher Miriam , Bohner Gerd , Rank Susanne
Published: June 2005

Zusammenfassung: In der Persuasionsforschung beinhaltet die Standard-Methode zur Untersuchung kognitiven Aufwands bei der Verarbeitung persuasiver Botschaften die Variation der Überzeugungskraft der Botschaftsargumente zwischen Versuchspersonen. Wenn Rezipienten diese Botschaften ausführlich verarbeiten, führen Botschaften mit starken Argumenten zu positiveren Einstellungen als Botschaften mit schwachen Argumenten. Die Standard-Methode birgt allerdings einige Nachteile: Die Qualität der Botschaft kann unerwünschterweise die Evaluation der Persuasionsquelle beeinflussen, Botschaften mit eindeutig schwachen oder starken Argumenten unterdrücken den Einfluss persuasiver Information, die nicht Teil der Botschaft ist, und sie eignen sich nicht zum Nachweis verzerrter Informationsverarbeitung. Die “Mixed-Message-Methode” überwindet diese Schwächen. Sie beinhaltet die Variation der Überzeugungskraft der Argumente zu einzelnen Aspekten innerhalb einer Botschaft. Die Differenzierung zwischen spezifisch auf unterschiedliche Aspekte bezogenen Einstellungsskalen kann als Maß für den kognitiven Aufwand bei der Verarbeitung persuasiver Botschaften dienen.
Blinder Mann sucht schöne Frau?
Authors: Hasenkamp Andrea , Kümmerling Angelika , Hassebrauck Manfred
Published: June 2005

Zusammenfassung: Untersuchungen zur Partnerwahl zeigen kulturübergreifend, dass Frauen einen älteren wohlhabenden Partner präferieren, Männer ihrerseits Jugendlichkeit und physische Attraktivität einer Partnerin. Geburtsblinden Personen ist einerseits die physische Attraktivität eines Menschen visuell nicht zugänglich, andererseits scheinen sie in ihren Möglichkeiten zur Ressourcenakquisition gesellschaftlich benachteiligt zu sein. Eine Telefonbefragung von 57 geburtsblinden (30 Frauen, 27 Männer) und 62 sehenden Personen (32 Frauen, 30 Männer) zeigte, dass diese Unterschiede in differierenden Partnerwahlkriterien resultieren: Geburtsblinden Frauen ist physische Attraktivität tendenziell wichtiger als geburtsblinden Männern und Ressourcenverfügung weniger wichtig als sehenden Frauen. Geburtsblinden Männern ist physische Attraktivität signifikant und Ressourcenbesitz tendenziell weniger wichtig als sehenden Männern. Diese Ergebnisse werden im Kontext des evolutionspsychologischen Erklärungsansatzes, der Theorie der strukturellen Machtlosigkeit und der Equitytheorie diskutiert.
Social Categorization Without Fit
Authors: Wegener Ingo , Klauer Karl Christoph
Published: June 2005

Abstract: Is intercategory fit a prerequisite of social categorization? Intercategory fit is given if more differences are perceived between than within two or more social categories. We created experimental conditions without objective fit, and ruled out subjective perceptions of intercategory fit, such as arise from expectancy-based illusory correlations. In the first experiment, portraits of men and women were presented together with nonsense syllables. Cued by the nonsense syllables, participants were later able to retrieve gender category information, indicating category salience in the presentation phase. The second experiment replicated these results using male and female first names instead of portraits. Inter-category fit thus does not constitute a necessary precondition for categorization. The results bear on the very early stages in the development of stereotypes.
Die Qualität intra- und interethnischer Freundschaften bei Mädchen und Jungen deutscher, türkischer und italienischer Herkunft
Authors: Reinders Heinz , Mangold Tanja
Published: June 2005

Zusammenfassung. Dieser Beitrag beschäftigt sich mit der Frage, ob sich die Qualität von intra- und interethnischen Freundschaften bei Mädchen und Jungen deutscher, türkischer und italienischer Herkunft unterscheidet. Diesbezügliche Hypothesen, die sich aus der Theorie der sozialen Distanz, dem Rational-Choice-Ansatz und dem Konzept der Ko-Kulturation ableiten lassen, werden getestet. Während die Theorie der sozialen Distanz eine geringere Qualität interethnischer Freundschaften erwarten lässt, legt das Konzept der Ko-Kulturation eine höhere Qualität gegenüber intraethnischen Beziehungen nahe. Der Rational-Choice-Ansatz führt zur Annahme einer vergleichbaren Qualität. Die Überprüfung wird anhand einer Studie bei Hauptschülern der 7. bis 9. Klasse vorgenommen. Die Ergebnisse zeigen, dass intra- und interethnische Freundschaften sich in ihrer Qualität gleichen und Geschlechtereffekte die übergeordnete Rolle für die Erklärung von Differenzen der Freundschaftsqualität spielen.
Submarine fault scarps in the Sea of Marmara pull‐apart (North Anatolian Fault): Implications for seismic hazard in Istanbul
Authors: Armijo Rolando , Pondard Nicolas , Meyer Bertrand , Uçarkus Gulsen , de Lépinay Bernard Mercier , Malavieille Jacques , Dominguez Stéphane , Gustcher Marc‐André , Schmidt Sabine , Beck Christian , Çagatay Namik , Çakir Ziyadin , Imren Caner , Eris Kadir , Natalin Boris , Özalaybey Serdar , Tolun Leyla , Lefèvre Irène , Seeber Leonardo , Gasperini Luca , Rangin Claude , Emre Omer , Sarikavak Kerim
Published: June 2005

Earthquake scarps associated with recent historical events have been found on the floor of the Sea of Marmara, along the North Anatolian Fault (NAF). The MARMARASCARPS cruise using an unmanned submersible (ROV) provides direct observations to study the fine‐scale morphology and geology of those scarps, their distribution, and geometry. The observations are consistent with the diversity of fault mechanisms and the fault segmentation within the north Marmara extensional step‐over, between the strike‐slip Ganos and Izmit faults. Smaller strike‐slip segments and pull‐apart basins alternate within the main step‐over, commonly combining strike‐slip and extension. Rapid sedimentation rates of 1–3 mm/yr appear to compete with normal faulting components of up to 6 mm/yr at the pull‐apart margins. In spite of the fast sedimentation rates the submarine scarps are preserved and accumulate relief. Sets of youthful earthquake scarps extend offshore from the Ganos and Izmit faults on land into the Sea of Marmara. Our observations suggest that they correspond to the submarine ruptures of the 1999 Izmit (Mw 7.4) and the 1912 Ganos (Ms 7.4) earthquakes. While the 1999 rupture ends at the immediate eastern entrance of the extensional Cinarcik Basin, the 1912 rupture appears to have crossed the Ganos restraining bend into the Sea of Marmara floor for 60 km with a right‐lateral slip of 5 m, ending in the Central Basin step‐over. From the Gulf of Saros to Marmara the total 1912 rupture length is probably about 140 km, not 50 km as previously thought. The direct observations of submarine scarps in Marmara are critical to defining barriers that have arrested past earthquakes as well as defining a possible segmentation of the contemporary state of loading. Incorporating the submarine scarp evidence modifies substantially our understanding of the current state of loading along the NAF next to Istanbul. Coulomb stress modeling shows a zone of maximum loading with at least 4–5 m of slip deficit encompassing the strike‐slip segment 70 km long between the Cinarcik and Central Basins. That segment alone would be capable of generating a large‐magnitude earthquake (Mw 7.2). Other segments in Marmara appear less loaded.
Acceleration and transport of heavy ions at coronal mass ejection‐driven shocks
Authors: Li Gang , Zank G. P. , Rice W. K. M.
Published: June 2005

It is now widely accepted that large solar energetic particle (SEP) events are associated with coronal mass ejection (CME)‐driven shocks. Here, particles are often accelerated to approximately MeV energies (and perhaps up to GeV energies) at shock waves driven by CMEs. In this paper, on the basis of our earlier work, we present a detailed model which calculates the acceleration of heavy ions at CME‐driven shocks and their subsequent propagation in the interplanetary medium. The CME‐driven shock is followed numerically using the two‐dimensional ZEUS code. At the shock front and upstream of the shock, the coupled system of streaming protons and stimulated upstream turbulence (assuming the form of Alfvén waves) is considered and the diffusion coefficient of the energetic ions and the stimulated wave intensity is evaluated self‐consistently. The particle diffusion coefficient is then used to determine the maximum momentum of energetic ions. The ion spectra at the shock front are obtained by adopting the steady‐state solution of the transport equation. Across the shock front, the upstream turbulence is amplified and the particle diffusion coefficient is further decreased. Energetic particles in the downstream region convect with the solar wind, cool adiabatically, and diffuse. These effects are followed using a shell model. Particles diffuse ahead of the shock front, can escape and propagate in the interplanetary medium subject to pitch angle scattering. The transport of these particles is followed using a Monte‐Carlo code. Two shocks, one strong and one weak, are considered. Time intensity profiles and particle spectra at various times are obtained for two groups of ions, corresponding to Fe and CNO particles. These results will be helpful on understanding in situ observations at 1 AU made by spacecraft such as ACE and Wind.
Contribution of nonadiabatic ions to the cross‐tail current in an O+ dominated thin current sheet
Authors: Kistler L. M. , Mouikis C. , Möbius E. , Klecker B. , Sauvaud J. A. , Réme H. , Korth A. , Marcucci M. F. , Lundin R. , Parks G. K. , Balogh A.
Published: June 2005

During storm times, O+ can dominate both the pressure and the density in the plasma sheet. Because of the contribution from ion outflow, the plasma sheet is already oxygen‐rich prior to substorm onset. At substorm onset the fraction of O+ contributing to the pressure and density increases. In the O+ dominated thin current sheet the O+ ions are observed to stream from dawn to dusk across the tail, as predicted for nonadiabatic ions by Speiser (1965). We calculate the current contribution from these ions and find that they carry about 5–10% of the cross‐tail current. During a nonstormtime substorm the general behavior of the O+ is the same. However, because there is less O+ present, the O+ never dominates over H+, and the contribution to the cross‐tail current is even less.
AE index variability during corotating fast solar wind streams
Authors: Diego P. , Storini M. , Parisi M. , Cordaro E. G.
Published: June 2005

We examine the AE index variability while 12 corotating fast solar wind streams pass the Earth during the ascending phase of the ongoing solar activity cycle. We apply the Discrete Fourier Transform analysis to the associated interplanetary magnetic field (B) data and AE time series with ∼1 min resolution. Results show noticeable periodicities in the 1–10 hour range. Moreover, the B and AE periodicities in each event are well correlated. For this reason a direct relationship between interplanetary Alfvénic waves and AE oscillations is proposed while those streams pass the Earth.
Alfven wave reflection in a curvilinear magnetic field and formation of Alfvenic resonators on open field lines
Authors: Pilipenko V. A. , Mazur N. G. , Fedorov E. N. , Engebretson M. J. , Murr D. L.
Published: June 2005

Though shear Alfven waves have no reflection points, these waves can be partially reflected from sharp field‐aligned variations in Alfven velocity. Such a reflection can lead to the formation of quasi‐resonators, such as the ionospheric Alfven resonator, in which wave energy can be accumulated. We show that a similar partial reflection of Alfven waves can occur in regions with steep variations of geomagnetic field line geometry. For that, the propagation of Alfven waves in a plasma immersed in a two‐dimensional (2‐D) curvilinear magnetic field has been investigated. The Alfven waves comprise two modes with different polarization, toroidal and poloidal, which are described by 1‐D equations. These equations formally coincide with the equation for the case of a quasi‐uniform straight magnetic field with a modified Alfven velocity that takes into account the field‐aligned dependence of the Lamé coefficients. The toroidal and poloidal modes depend differently on the magnetic field geometry. The poloidal mode is efficiently reflected from regions where the magnetic field lines sharply converge or diverge, when its wavelength becomes comparable to the typical scale of magnetic field convergence. This effect can result in the formation of Alfven quasi‐resonators on open field lines. This mechanism can be used to interpret the occurrence of specific polar cap quasi‐periodic Pi3 pulsations with periods ∼15–20 min observed by the AGO magnetometer array in Antarctica. Also, such a reflection can limit the influx of Alfvenic wave energy along reconnected field lines from the solar wind into the magnetosphere at certain wavelengths. This effect has been observed as the occurrence of a low‐pass cutoff period ∼10–15 min in the spectral transfer function between conjugate IMF variations and ground magnetic disturbances.
Ion distributions in Saturn's magnetosphere near Titan
Authors: Ledvina S. A. , Cravens T. E. , Kecskeméty K.
Published: June 2005

Titan's interaction with Saturn's magnetosphere is studied using a combination of a three‐dimensional (3‐D) single‐fluid magnetohydrodynamic (MHD) simulation and a test particle/Monte Carlo model. The MHD simulation includes an exosphere model based on the one used in the work of Cravens et al. (1998), simple ionospheric processes such as ion production, ion‐neutral friction and dissociative recombination and provides a general picture of Titan's plasma environment. The fields from the MHD simulation are then used to calculate the trajectories of 1.4 × 106 ions. We calculate the velocity space distribution and differential energy flux for ambient H+ and N+ ions and for three generic species of pickup ions found upstream of, and within, Titan's plasma wake. The three generic pickup ion species we use are: light (e.g., H+ or H2+), medium (e.g., N+, CH4+, or CH5+), and heavy (e.g., N2+, HCNH+, or some other ionized heavy exospheric species) with representative masses 1, 14, and 28 amu. We also determine the ion flux into Titan's exobase for each species. The ambient ions are assumed to have a drifting Maxwellian distribution consistent with the Voyager observations, while the pickup ions are created with a radial distribution proportional to the neutral density profiles from the neutral exosphere model used in the 2‐D MHD model of Cravens et al. (1998). The possibility that the ambient N+ ions may have a shell distribution rather than a Maxwellian is also considered. The modeled ion distributions are compared with data from the Voyager 1 Plasma Science Instrument (PLS).
Nonlocal interactions between electrons and Alfvén waves on auroral field lines
Authors: Lysak Robert L. , Song Yan
Published: June 2005

The interaction of auroral electrons with kinetic Alfvén waves is complicated by the fact that the Alfvén speed above the ionosphere is strongly inhomogeneous, leading to a region often referred to as the ionospheric Alfvén resonator (IAR). For these waves, the wave‐particle interaction must be treated with a nonlocal kinetic approach. Linear damping of these waves due to the wave‐particle interaction has been calculated based on a quasi‐dipolar field line model; however, particle orbits in the wave field are not well described by perturbation theory due to the development of new turning points in the particle trajectories, especially for low‐energy particles. Full orbit calculations of such particles have been performed in order to assess the validity of the linear theory and to determine how much wave energy is converted into electron energy flux that is precipitated into the ionosphere. In addition, the precipitating electrons show a phase shift with respect to the field‐aligned current in the waves, leading to a modification of theories of ionospheric feedback in the ionospheric Alfvén resonator.
Computing the reconnection rate at the Earth's magnetopause using two spacecraft observations
Authors: Fuselier S. A. , Trattner K. J. , Petrinec S. M. , Owen C. J. , Rème H.
Published: June 2005

A new multispacecraft technique is introduced which, under some restrictive assumptions and conditions, provides a snapshot of the reconnection inflow velocity into the magnetosphere and an estimate of the distance from the spacecraft to the reconnection site. The two quantities are not obtained independent of one another and additional, independent information is needed to separate them. This new technique is applied to Cluster spacecraft observations at the Earth's magnetopause. Additional Cluster observations and observations from the IMAGE spacecraft are used as independent information to provide an estimate of the distance from the spacecraft to the reconnection site for the event. From this distance estimate and the new multispacecraft technique, it is concluded that component reconnection was probably occurring at the magnetopause and that the local inflow velocity was significantly less than 0.1 VA.
Internal reconnection for northward interplanetary magnetic field
Authors: Watanabe Masakazu , Kabin Konstantin , Sofko George J. , Rankin Robert , Gombosi Tamas I. , Ridley Aaron J. , Clauer C. Robert
Published: June 2005

On the basis of magnetohydrodynamic simulation results for northward interplanetary magnetic field (IMF) and significant dipole tilt, we describe internal reconnection processes that occur earthward of the magnetopause subsequent to magnetopause reconnection. We discuss the associated ionospheric signatures and show that the internal reconnection occurs not only between a summer lobe and a winter lobe field line but also between a summer lobe field line and a closed field line. The latter internal reconnection drives a pair of convection cells circulating outside the polar cap in the winter ionosphere. In this paper, we refer to these convection cells as “reciprocal cells” and the corresponding reconnection as reciprocal cell reconnection. The reciprocal cells are coupled to the so‐called lobe cells that are driven by magnetopause reconnection between an IMF line and a summer lobe field line (lobe cell reconnection); these lobe cells circulate inside the polar cap in the summer ionosphere. The reciprocal cell reconnection converts an overdraped lobe field line to a relaxed lobe field line, while the lobe cell reconnection converts a relaxed lobe field line to an overdraped lobe field line. Thus the reciprocal cell reconnection reciprocates with the lobe cell reconnection through the exchange of magnetic flux.
Fault zone restrengthening and frictional healing: The role of pressure solution
Authors: Yasuhara Hideaki , Marone Chris , Elsworth Derek
Published: June 2005

Laboratory and field observations note the significant role of strength recovery (healing) on faults during interseismic periods and implicate pressure solution as a plausible mechanism. Plausible rates for pressure solution to activate, and the magnitudes of ultimate strength gain, are examined through slide‐hold‐slide experiments using simulated quartz gouge. Experiments are conducted on fine‐grained (110 μm) granular silica gouge, saturated with deionized water, confined under constant normal stress of 5 MPa and at modest temperatures of 20 and 65°C, and sheared at a maximum rate of 20 μm/s. Data at 20°C show a log linear relation between strength gain and the duration of holding periods, whereas the higher temperature observations indicate higher healing rates than the log linear dependencies; these are apparent for hold times greater than ∼1000 s. This behavior is attributed to the growth and welding of grain contact areas, mediated by pressure solution. The physical dependencies of this behavior are investigated through a mechanistic model incorporating the serial processes of grain contact dissolution, grain boundary diffusion, and precipitation at the rim of contacts. We use the model to predict strength gain for arbitrary conditions of mean stress, fluid pressure, and temperature. The strength gain predicted under the experimental conditions (σeff = 5 MPa and T = 65°C) underestimates experimental measurements for hold periods of less than ∼1000 s where other frictional mechanisms contribute to strength gain. Beyond this threshold, laboratory observations resemble the trend in the prediction by our mechanistic model, implicating that pressure solution is likely the dominant mechanism for strength gain. The model is applied to the long‐term prediction of healing behavior in quartzite fault zones. Predictions show that both rates and magnitudes of gain in contact area increase with an increase in applied stresses and temperatures and that fault healing aided by pressure solution should reach completion within recurrence interval durations ranging from <1 to ∼104 years, depending on applied stresses, temperatures, and reaction rates.
Atmospheric water vapor and geoid measurements in the open ocean with GPS
Authors: Rocken Christian , Johnson James , Van Hove Teresa , Iwabuchi Tetsuya
Published: June 2005

We have conducted two experiments to determine precipitable water vapor (PWV) and sea surface heights from a cruising ship in the open ocean. During the first experiment (July 7–13, 02) GPS and radiosonde PWV agreed at the 2 mm rms level. During the second experiment (Aug 23–30, 03) GPS compared at 1.5 mm rms (1.1 mm GPS high bias) with eight ship‐launched radiosondes and at 2.8 mm rms (1.2 mm GPS high bias) to a ship‐based water vapor radiometer (WVR). We estimate that the vertical position of the GPS antenna in the open ocean was determined to better than 10 cm rms. After correcting for ocean tides GPS estimated sea surface heights from the second cruise compared to the CARIB97 geoid at the 32 cm level in the vertical. Because space based observations of PWV over the oceans generally require cloudless conditions and are accurate to about 5–10% we conclude that ship based GPS observations can provide additional useful meteorological information. Based on the 10‐cm vertical position rms and the high horizontal resolution of ship‐based positions we further conclude that useful geodetic information can be obtained from high accuracy GPS observations from ships in the open oceans.
Tracking precursors and degassing by radon monitoring during major eruptions at Stromboli Volcano (Aeolian Islands, Italy)
Authors: Cigolini C. , Gervino G. , Bonetti R. , Conte F. , Laiolo M. , Coppola D. , Manzoni A.
Published: June 2005

We monitored radon anomalies before, during and after the recent paroxysmal eruptions of Stromboli. Major eruptive events are preceded by relative minima in radon emissions at stations located at the base of the cone, whereas three of the summit stations reached peak values (∼20,000 Bq/m3 or higher) 12 to 14 days before major eruptions, and are nearly coeval with earth tides. Radon emissions at/or above such high threshold values are proposed to result from the dynamic response of the fracture network due to degassing processes associated with magma ascent. Relative minima recorded at the base of the cone are related to fractures' self‐sealing within the hydrothermal system, eventually coupled with the atmospheric stack‐effect. The coexistence of the above anomalies is interpreted as the first precursory signals to major eruptive events.
Instantaneous electric field measurements and derived neutral winds at Arecibo
Authors: Aponte Néstor , Nicolls Michael J. , González Sixto A. , Sulzer M. P. , Kelley Michael C. , Robles Eva , Tepley Craig A.
Published: June 2005

Previously, ion vector velocity measurements at Arecibo required the rotation of the antenna (a 360° rotation takes about 15 minutes) in order to accumulate enough information from different directions. In addition, a least‐squares fitting method or a more sophisticated inversion technique is necessary to determine horizontal velocities. This study reports the first instantaneous long‐duration F region vector velocity measurements in the magnetic meridian plane using the dual‐beam system. This configuration is suitable for measuring the eastward electric field and deriving the meridional neutral wind with very high time resolution. The first results of this experiment presented here seem to show evidence for a gravity wave driven plasma process.
Source analysis of the 2002 Molise, southern Italy, twin earthquakes (10/31 and 11/01)
Authors: Vallée Martin , Di Luccio Francesca
Published: June 2005

On October 31, 2002, a moderate size earthquake (Mw = 5.8) occurred in Molise region, southern Italy, causing loss of young human lives in a school collapse and destructions in several villages. The day after, a slightly smaller earthquake happened a few kilometers westward from the first one, without making strong damage. We use a complete set of seismological data (global, regional and local, including both body and surface waves) to better understand the source process of these two events. We show that the two earthquakes are similar, in terms of hypocentral depth, focal mechanism, and source kinematics. Moreover, the imaged slip zones are almost contiguous which makes the time delay between the two shocks (29 hours) an open question. The identified updip rupture propagation has amplified the radiation usually created by such Mw = 5.8 earthquakes at 15–20 km depth. We model a maximum acceleration zone in agreement with location of damaged villages.
Do aircraft black carbon emissions affect cirrus clouds on the global scale?
Authors: Hendricks J. , Kärcher B. , Lohmann U. , Ponater M.
Published: June 2005

Potential cirrus modifications caused by aircraft‐produced black carbon (BC) particles via heterogeneous ice nucleation were studied with a general circulation model. Since the role of BC in cirrus cloud formation is currently not well known, hypothetical scenarios based on various assumptions on the ice nucleation efficiency of background and aircraft‐induced BC particles were considered. Using these scenarios, the sensitivity of ice cloud microphysics to aviation‐induced BC perturbations is studied. The model results suggest that cloud modifications induced by aircraft BC particles could change the ice crystal number concentration at northern midlatitudes significantly (10–40% changes of annual mean zonal averages at main flight altitudes), provided that such BC particles serve as efficient ice nuclei. The sign of the effect depends on the specific assumptions on aerosol‐induced ice nucleation. These results demonstrate that, based on the current knowledge, significant cirrus modifications by BC from aircraft cannot be excluded.
The local and global effects of African deforestation
Authors: Werth David , Avissar Roni
Published: June 2005

Using a global climate model (GCM), we simulate the effects of the total deforestation of equatorial Africa, looking specifically at the local and remote precipitation changes caused by such a land‐use change. We observe a strong local effect, with a large reduction in African precipitation during the dry season, and little change during either of the two rainy seasons. The effects of African deforestation extend throughout the Tropics and also reach into the midlatitudes. The remote effect is caused by the African geopotential changes being spread beyond the deforested area by the large‐scale winds.
Contrasting seismicity between the north China and south China blocks: Kinematics and geodynamics
Authors: Liu Mian , Yang Youqing
Published: June 2005

The north China block (NCB), part of the Sino‐Korean craton, is surprisingly one of the most active seismic regions in the world. The south China block (SCB), another major craton in East Asia, has been seismically quiescent. Using the updated GPS data and finite element modeling, we show that the kinematic boundary conditions are the primary cause of the contrasting seismicity. The SCB, facilitated by large strike‐slip faults on its boundaries, moves coherently as a rigid block. Conversely, sandwiched between the expanding Tibetan plateau and the stable Siberia, the NCB experiences large differential stresses, which are further enhanced by faulting and thermal thinning of the lithosphere. The spatial agreement between seismic energy release in the past ∼2000 years and the predicted long‐term strain energy implies that intense seismicity in the NCB may continue in the future.
Strong surface melting preceded collapse of Antarctic Peninsula ice shelf
Authors: van den Broeke Michiel
Published: June 2005

During the austral summer of 2001/02, melting at the surface of Larsen Ice Shelf in the Antarctic Peninsula was three times greater than the average of five previous summers. This exceptional melt event lasted for three months and was followed by the collapse of Larsen B Ice Shelf, during which 3,200 km2 of ice shelf surface was lost. The strong melting was caused by a persistent atmospheric circulation anomaly, which depleted sea ice concentrations in front of Larsen Ice Shelf and transported warm air to the ice shelf throughout the 2001/02 summer. This supports the theory that large meltwater fluxes accelerate the retreat of Antarctic Peninsula ice shelves.
Suprathermal electrons in high‐speed streams from coronal holes: Counterstreaming on open field lines at 1 AU
Authors: Steinberg J. T. , Gosling J. T. , Skoug R. M. , Wiens R. C.
Published: June 2005

Using ACE and Genesis data, suprathermal electron measurements within high‐speed streams and their associated corotating interaction regions (CIRs) have been analyzed. Enhanced fluxes of sunward streaming suprathermal electrons are consistently observed following the passage of a corotating interaction region (CIR) over spacecraft at 1 AU. A backstreaming electron beam, produced at the CIR, is observed whether the CIRs are bounded by reverse shocks or reverse pressure waves. Because an antisunward directed electron strahl distribution is also normally present, electron counterstreaming results. Counterstreaming following CIRs can last for more than 2 days, after which time a 1 AU spacecraft is magnetically connected to a CIR at 3–5 AU. Although electron counterstreaming is frequently associated with closed field lines of interplanetary coronal mass ejections (ICMEs), electron counterstreaming associated with CIRs occurs on open field lines. Occasionally, electron counterstreaming associated with CIR‐produced suprathermal electrons is also seen within the slow wind preceding a CIR. In each such case observed the counterstreaming lasted less than 1 day.
Dust & Magnet: Multivariate Information Visualization Using a Magnet Metaphor
Authors: Soo Yi Ji , Melton Rachel , Stasko John , Jacko Julie A.
Published: June 2005

The use of multivariate information visualization techniques is intrinsically difficult because the multidimensional nature of data cannot be effectively presented and understood on real-world displays, which have limited dimensionalities. However, the necessity to use these techniques in daily life is increasing as the amount and complexity of data grows explosively in the information age. Thus, multivariate information visualization techniques that are easier to understand and more accessible are needed for the general population. In order to meet this need, the present paper proposes Dust & Magnet, a multivariate information visualization technique using a magnet metaphor and various interactive techniques. The intuitive magnet metaphor and subsequent interactions facilitate the ease of learning this multivariate information visualization technique. A visualization tool such as Dust & Magnet has the potential to increase the acceptance of and utility for multivariate information by a broader population of users who are not necessarily knowledgeable about multivariate information visualization techniques.
Visualizing Biological Pathways: Requirements Analysis, Systems Evaluation and Research Agenda
Authors: Saraiya Purvi , North Chris , Duca Karen
Published: June 2005

Pathway diagrams are used by life scientists to represent complex interactions at the molecular level in living cells. The recent shift towards data-intensive bioinformatics and systems-level science has created a strong need for advanced pathway visualizations that support exploratory analysis. This paper presents a comprehensive list of requirements for pathway visualization systems, based on interviews conducted to understand life scientists' needs for pathway analysis. A variety of existing pathway visualization systems are examined, to analyze common approaches by which the contemporary systems address these requirements. A heuristic evaluation, by biology domain experts, of five popular pathway visualization systems is conducted to analyze the end-user perception of these systems. Based on these studies, a research agenda is presented concerning five critical requirements for pathway visualization systems. If addressed effectively, these requirements can prove to be most helpful in supporting exploratory pathway analysis. These include: (1) automated construction and updating of pathways by searching literature databases, (2) overlaying information on pathways in a biologically relevant format, (3) linking pathways to multi-dimensional data from high-throughput experiments such as microarrays, (4) overviewing multiple pathways simultaneously with interconnections between them, (5) scaling pathways to higher levels of abstraction to analyze effects of complex molecular interactions at higher levels of biological organization.
Effect of chain length and asymmetry on material properties of bilayer membranes
Authors: Illya G. , Lipowsky R. , Shillcock J. C.
Published: June 2005

Dissipative particle dynamics is used to extract the material parameters (bending and area stretch moduli) of a bilayer membrane patch. Some experiments indicate that the area stretch modulus of lipid vesicles varies little as the chain length of the lipids composing the bilayer increases. Here we show that making the interactions between the hydrophilic head groups of the model amphiphiles proportional to the hydrophobic tail length reproduces the above result for the area stretch modulus. We also show that the area stretch modulus of bilayers composed of amphiphiles with the same number of tail beads but with asymmetric chains is less than that of bilayers with symmetric chains. The effects on the bilayer density and lateral stress profiles of changes to the amphiphile architecture are also presented.
An efficient approach for the calculation of Franck–Condon integrals of large molecules
Authors: Dierksen Marc , Grimme Stefan
Published: June 2005

A general and efficient approach for the calculation of Franck–Condon integrals (FCIs) of large molecules is presented. In a first step, by exploiting the diagonally dominant and sparse structure of the Duschinsky matrix, a model system is constructed for which the Duschinsky matrix takes a block-diagonal form. For each of these blocks separately, the FCIs are calculated discarding all below a certain threshold. From those integrals retained the FCIs of the model system are obtained by simple multiplication. These serve as an estimate for the FCIs of the exact system which are calculated for those integrals which lie above a certain threshold. By systematically decreasing the threshold, the simulation can be reliably converged to the exact result with an arbitrary accuracy. Using this scheme, a considerable reduction of the number of FCIs which have to be calculated is achieved which leads to an improved scaling behavior of the computational effort with system size. The approach has been tested thoroughly for a set of molecules including difficult cases. For the larger systems a speedup of up to three orders of magnitude compared to an exact calculation is observed while the errors can be kept negligible. With this approach accurate calculations of FCIs are feasible also for large molecules encountered in “real-life” chemistry, especially biochemistry and material science.
Electronic quantum Monte Carlo calculations of atomic forces, vibrations, and anharmonicities
Authors: Lee Myung Won , Mella Massimo , Rappe Andrew M.
Published: June 2005

Atomic forces are calculated for first-row monohydrides and carbon monoxide within electronic quantum Monte Carlo (QMC). Accurate and efficient forces are achieved by using an improved method for moving variational parameters in variational QMC. Newton’s method with singular value decomposition (SVD) is combined with steepest-descent (SD) updates along directions rejected by the SVD, after initial SD steps. Dissociation energies in variational and diffusion QMC agree well with the experiment. The atomic forces agree quantitatively with potential-energy surfaces, demonstrating the accuracy of this force procedure. The harmonic vibrational frequencies and anharmonicity constants, derived from the QMC energies and atomic forces, also agree well with the experimental values.
The vibrational predissociation spectra of the H5O2+∙RGn(RG=Ar,Ne) clusters: Correlation of the solvent perturbations in the free OH and shared proton transitions of the Zundel ion
Authors: Hammer Nathan I. , Diken Eric G. , Roscioli Joseph R. , Johnson Mark A. , Myshakin Evgeniy M. , Jordan Kenneth D. , McCoy Anne B. , Huang Xinchuan , Bowman Joel M. , Carter Stuart
Published: June 2005

Predissociation spectra of the H5O2+∙RGn(RG=Ar,Ne) cluster ions are reported in energy regions corresponding to both the OH stretching (3350–3850cm−1) and shared proton (850–1950cm−1) vibrations. The two free OH stretching bands displayed by the Ne complex are quite close to the band origins identified earlier in bare H5O2+ [L. I. Yeh, M. Okumura, J. D. Myers, J. M. Price, and Y. T. Lee, J. Chem. Phys. 91, 7319 (1989)], indicating that the symmetrical H5O2+ “Zundel” ion remains largely intact in H5O2+∙Ne. The low-energy spectrum of the Ne complex is simpler than that observed previously for H5O2+∙Ar, and is dominated by two sharp transitions at 928 and 1047cm−1, with a weaker feature at 1763cm−1. The H5O2+∙Arn,n=1–5 spectra generally exhibit complex band structures reflecting solvent-induced symmetry breaking of the Zundel core ion. The extent of solvent perturbation is evaluated with electronic structure calculations, which predict that the rare gas atoms should attach to the spectator OH groups of H5O2+ rather than to the shared proton. In the asymmetric complexes, the shared proton resides closer to the more heavily solvated water molecule, leading to redshifts in the rare gas atom-solvated OH stretches and to blueshifts in the shared proton vibrations. The experimental spectra are compared with recent full-dimensional vibrational calculations (diffusion Monte Carlo and multimode/vibrational configuration interaction) on H5O2+. These results are consistent with assignment of the strong low-energy bands in the H5O2+∙Ne spectrum to the vibration of the shared proton mostly along the O–O axis, with the 1763cm−1 band traced primarily to the out-of-phase, intramolecular bending vibrations of the two water molecules.
Numerical investigation of three-dimensional single-species plasma equilibria on magnetic surfaces
Authors: Lefrancois Remi G. , Pedersen Thomas Sunn , Boozer Allen H. , Kremer Jason P.
Published: June 2005

Presented for the first time are numerical solutions to the three-dimensional nonlinear equilibrium equation for single-species plasmas confined on magnetic surfaces and surrounded by an equipotential boundary. The major-radial shift of such plasmas is found to be outward, qualitatively similar to the Shafranov shift of quasineutral plasmas confined on magnetic surfaces. However, this is the opposite of what occurs in the pure toroidal field equilibria of non-neutral plasmas (i.e., in the absence of magnetic surfaces). The effect of varying the number of Debye lengths in the plasma for the three-dimensional (3D) model is in agreement with previous 2D calculations: the potential varies significantly on magnetic surfaces for plasmas with few Debye lengths (a≲λd), and tends to be constant on surfaces when many Debye lengths are present (a≳10λd). For the case of a conducting boundary that does not conform to the outer magnetic surface, the plasma is shifted towards the conductor and the potential varies significantly on magnetic surfaces near the plasma edge. Debye shielding effects are clearly demonstrated when a nonuniform bias is applied to the boundary. Computed equilibrium profiles are presented for the Columbia Non-Neutral Torus [T. S. Pedersen, A. H. Boozer, J. P. Kermer, R. Lefrancois, F. Dahlgren, N. Pomphrey, W. Reiersen, and W. Dorland, Fusion Sci. Technol. 46, 200 (2004)], a stellarator designed to confine non-neutral plasmas.
QUALITAS: A mid-infrared spectrometer for sensitive trace gas measurements based on quantum cascade lasers in CW operation
Authors: Kormann R. , Königstedt R. , Parchatka U. , Lelieveld J. , Fischer H.
Published: June 2005

We describe QUALITAS, a mid-infrared spectrometer with multipass absorption cell, suitable to apply lead chalcogenide and quantum cascade lasers as light sources in CW operation at cryogenic temperatures. The instrument has been designed for the measurement of trace gases such as carbon monoxide, nitrous oxide or methane in the clean atmosphere from space-restricted and experimentally challenging mobile platforms. The design involves compact optics, which fit into the space limitations of a standard aircraft borne 19in. rack (W×H×D≈48×45×40cm3). The instrument allows high sensitivity (≈5×10−7m−1Hz−1∕2 during flight; ≈1×10−7m−1Hz−1∕2 in the laboratory) in combination with a low sample gas volume (0.3L) for high time resolution (<1s, using a moderately sized pump). We employ a combination of elements already applied in former spectrometers in our laboratory and a novel arrangement of spherical mirrors. The design criteria, the optical, electronic and mechanical set-up are described in detail. The application of the instrument to measure atmospheric concentrations of carbon monoxide is discussed, using both, a lead chalcogenide as well as a DFB-structured quantum cascade laser (R3 line at 2158.3cm−1).
Qualitative features of the two-dimensional Raman spectrum in liquids
Authors: Keyes T. , Kim Joohyun
Published: June 2005

The theory presented earlier [J. Kim and T. Keyes, Phys. Rev. E 66, 051110 (2002)] is analyzed to determine the information available from the two-dimensional Raman spectrum R(5)(t2,t1) in liquids. The known spectra are well represented by the sum of two products of ordinary time correlations predicted by the theory. The shape of R(5) is related in general to the values of simple same-time averages and concepts amenable to physical intuition. Using standard models for the time correlations entering the theory, specific analytic expressions for the spectrum are obtained depending on two parameters and a time scale, and the behavior of the spectrum is mapped out in the parameter space.
Nonequilibrium vibrational excitation of H2 in radiofrequency discharges: A theoretical approach based on coherent anti-Stokes Raman spectroscopy measurements
Authors: Hassouni K. , Lombardi G. , Gicquel A. , Capitelli M. , Shakhatov V. A. , De Pascale O.
Published: June 2005

Vibrational and rotational experimental temperatures of molecular hydrogen obtained by coherent anti-Stokes Raman spectroscopy in radiofrequency inductive plasmas have been analyzed and interpreted in terms of vibration, electron, dissociation-recombination, and attachment kinetics by using a sophisticated kinetic model recently developed. The analysis clarifies the role of atomic hydrogen in affecting the vibrational content of the molecules. Theoretical plasma composition and population and electron energy distributions are presented as a function of the recombination coefficient γH of atomic hydrogen on the surfaces. The agreement between theoretical and experimental results is achieved for recombination coefficients consistent with those found in the literature.
Growth dynamics of reactive-sputtering-deposited AlN films
Authors: Auger M. A. , Vázquez L. , Sánchez O. , Jergel M. , Cuerno R. , Castro M.
Published: June 2005

We have studied the surface kinetic roughening of AlN films grown on Si(100) substrates by dc reactive sputtering within the framework of the dynamic scaling theory. Films deposited under the same experimental conditions for different growth times were analyzed by atomic force microscopy and x-ray diffraction. The AlN films display a (002) preferred orientation. We have found two growth regimes with a crossover time of 36min. In the first regime, the growth dynamics is unstable and the films present two types of textured domains, well textured and randomly oriented, respectively. In contrast, in the second regime the films are homogeneous and well textured, leading to a relative stabilization of the surface roughness characterized by a growth exponent β=0.37±0.03. In this regime a superrough scaling behavior is found with the following exponents: (i) Global exponents: roughness exponent α=1.2±0.2 and β=0.37±0.03 and coarsening exponent 1∕z=0.32±0.05; (ii) local exponents: αloc=1, βloc=0.32±0.01. The differences between the growth modes are found to be related to the different main growth mechanisms dominating their growth dynamics: sticking anisotropy and shadowing, respectively.
Nanoheteroepitaxial growth of GaN on Si nanopillar arrays
Authors: Hersee S. D. , Sun X. Y. , Wang X. , Fairchild M. N. , Liang J. , Xu J.
Published: June 2005

Nanoheteroepitaxial growth of GaN by metal-organic chemical-vapor deposition on dense arrays of (111) Si nanopillars has been investigated. Scanning electron microscopy, cross-sectional transmission electron microscopy, and electron-diffraction analysis of 0.15-μm-thick GaN layers indicate single-crystal films. Most of the mismatch defects were in-plane stacking faults and the threading dislocation concentration was <108cm−2 at the interface and decreased away from the interface. High-resolution transmission electron microscopy indicated that grain-boundary defects could heal and were followed by high quality, single-crystal GaN. Facetted voids were also present at the GaN∕Si interface and are believed to be an additional strain-energy reduction mechanism. The unusual defect behavior in these samples appears to be related to the high compliance of the nanopillar silicon substrate.
Optical transmission through inelastically deformed shocked sapphire: stress and crystal orientation effects
Authors: Fat’yanov O. V. , Webb R. L. , Gupta Y. M.
Published: June 2005

Plane shock wave experiments were performed to examine optical transmission in sapphire single crystals (c cut, a cut, and r cut) compressed to longitudinal stresses ranging between 119 and 260kbar. Peak stress and particle velocity values in our experiments were obtained by compiling and analyzing published continuum data on shocked sapphire crystals. Time-resolved measurements, with nanosecond resolution, showed time-, stress-, and orientation-dependent changes in optical transmission beyond the Hugoniot elastic limit. Over the 300–680-nm range examined in our work, no wavelength dependence was observed. Loss of optical transmission in the stress range examined is due to inelastic deformation in shocked sapphire crystals. The present data reveal that inelastic deformation mechanisms are different in r-cut sapphire compared to a-cut and c-cut sapphire, and may be different for all three orientations examined. Although quantitative analysis of the time-dependent optical transmission data is not possible at present, optical transmission results have provided insight into inelastic deformation mechanisms in shocked sapphire. Present results are expected to be valuable for use of sapphire windows in shock wave experiments.