bluuebunny/crossref_metadata_2025 huggingface dataset:
‘GOD OF INDEPENDENCE, GOD OF PEACE’: VILLAGE POLITICS AND NATIONALISM IN THE MAQUIS OF CAMEROON, 1957–71
Authors: TERRETTA MEREDITH
Published: March 2005

The story of freedom fighter Jean Djonteu provides a new approach to the history of Union des populations du Cameroun (UPC) nationalism in the Grassfields and Mungo regions of Cameroon. Within the context of Baham, his village of origin, Djonteu's actions and tracts reveal his politico-spiritual reasons for joining the UPC militia in its revolutionary fight against Franco-Cameroonian state administration. UPC nationalism and village political culture formed a hybrid of political ideologies, or a ‘village nationalism’ articulating UPC anti-colonialism with Grassfields political concepts of nation and sovereignty that pre-dated European occupation. As this articulation disintegrated, Grassfields populations disengaged from state politics and turned inwards towards village political culture and spirituality rekindled by popular involvement in the UPC nationalist movement.
AMBACA SOCIETY AND THE SLAVE TRADE c. 1760–1845
Authors: VANSINA JAN
Published: March 2005

The slave trade in Angola, specifically in the district of Ambaca, transformed the social organization of its inhabitants at the grass-roots level by introducing an ever increasing quantity of coveted commodities and by providing credit in counterpart for pawnship. The trade provoked both the emergence of a new structure, the corporate matrilineage and the apparition of a new elite, when colonial chiefs coopted their commercial rivals, including local leaders who had efficiently used the assets of their corporate matrilineages to further their individual ambitions.
Hukm: THE CREOLIZATION OF AUTHORITY IN CONDOMINIUM SUDAN
Authors: WILLIS JUSTIN
Published: March 2005

Recent scholarship on ‘neo-traditionalism’ and colonial governance in Africa has challenged assumptions about the ‘invention of tradition’ and the ability of the colonial state to create wholly innovative kinds of local authority. This article explores one episode in the development of the authority of Ali el Tom, probably the most famous ‘traditional’ ruler in Condominium Sudan. It suggests that Ali el Tom's authority was a creole product, which drew on local moral codes and colonial forms of authority, but was not fully part of either. The willingness of his people to accept this sometimes abusive authority relied on a partly illusory sense that it was familiar; but this willingness was not unlimited, and on occasion actions from below set limits to the invention of authority and tradition.
Macrobenthic animal assemblages of the continental margin off Chile (22° to 42°S)
Authors: Palma Maritza , Quiroga Eduardo , Gallardo Victor A. , Arntz Wolf , Gerdes Dieter , Schneider Wolfgang , Hebbeln Dierk
Published: March 2005

A quantitative study of macrobenthos was carried out on three transects on the shelf and continental slope off Chile (22° to 42°S; from 100 to 2000 m water depth) within and beneath the oxygen minimum zone (OMZ). Macrobenthos mean densities ranged from 104 to 13 808 ind m−2, with highest values off Concepción (∼36°S), where highest chloroplastic pigment equivalents were also measured. Polychaetes were the numerically dominant group in all transects and depths, followed by peracarid crustaceans. Species richness and diversity correlated with observed changes in bottom-water oxygen concentrations and sediment-bound pigments. Our results show that the shelf macrobenthic communities were negatively affected by low oxygen. The non-metric multidimensional scaling (nMDS) analysis evidenced depth-related station groups which may be related to the different environments provided by the water masses involved. Indeed, the depth ranges of stations groups with their specific species inventories coincide quite well with the boundaries of the three important water masses in the region, the Equatorial Subsurface Water (∼50 m to ∼400 m depth), the Antarctic Intermediate Water (∼400 to ∼1200 m depth), and the Pacific Deep Water (>1200 m depth).
Cytotoxicity as a marker of mussel health status
Authors: Malagoli Davide , Ottaviani Enzo
Published: March 2005

Cytotoxic activity of the mollusc Mytilus galloprovincialis haemolymph was considered as a possible marker of mussel health status. An easy-to-use and low-cost cytotoxicity test was set up to assess whether cytotoxicity is influenced by environmental stress such as an increase in water temperature or a reduction in water pH or salinity. Experiments demonstrated that, despite great variability in cytotoxic activity among the mussel populations, changes in the water physical conditions reduce mussel cytotoxicity, making animals more vulnerable to pathogen aggression.
Deep-sea ophiuroids (Echinodermata) from reducing and non-reducing environments in the North Atlantic Ocean
Authors: Stöhr Sabine , Segonzac Michel
Published: March 2005

The animal communities associated with the deep-sea reducing environment have been studied for almost 30 years, but until now only a single species of ophiuroid, Ophioctenella acies, has been found at both hydrothermal vents and methane cold seeps. Since the faunal overlap between vent and seep communities is small and many endemic species have been found among other taxa (e.g. Mollusca, Crustacea), additional species of ophiuroids were expected at previously unstudied sites. Chemical compositions at reducing sites differ greatly from the nearby bathyal environment. Generally, species adapted to chemosynthetic environments are not found in non-chemosynthetic habitats, but occasional visitors of other bathyal species to vent and seep sites have been recorded among many taxa except ophiuroids. This paper presents an analysis of the ophiuroid fauna found at hydrothermal vents and non-reducing nearby sites on the Mid-Atlantic Ridge and on methane cold seeps in the Gulf of Mexico, at Blake Ridge off South Carolina and south of Barbados. In addition to O. acies, four species were found at vents, Ophiactis tyleri sp. nov., Ophiocten centobi, Ophiomitra spinea and Ophiotreta valenciennesi rufescens. While Ophioctenella acies appears to be restricted to chemosynthetic areas, the other four species were also found in other bathyal habitats. They also occur in low numbers (mostly single individuals), whereas species adapted to hydrothermal areas typically occur in large numbers. Ophioscolex tripapillatus sp. nov. and Ophiophyllum atlanticum sp. nov. are described from nearby non-chemosynthetic sites. In a cold seep south of Barbados, three species of ophiuroids were found, including Ophioctenella acies, Amphiura sp., Ophiacantha longispina sp. nov. and Ophioplinthaca chelys. From the cold seeps at Blake Ridge and the Gulf of Mexico, Ophienigma spinilimbatum gen. et sp. nov. is described, likely restricted to the reducing environment. Ophiotreta valenciennesi rufescens occurred abundantly among Lophelia corals in the Gulf of Mexico seeps, which is the first record of this species from the West Atlantic. Habitat descriptions complement the taxonomic considerations, and the distribution of the animals in reducing environments is discussed.
Gender and boys' singing in early childhood
Authors: Hall Clare
Published: March 2005

This article derives from a research project investigating the singing behaviour of a group of Australian boys in their first year of school. The project showed that the genesis of the ‘missing male’ trend in singing at school may be occurring in early childhood. The impact of hegemonic masculinity in early childhood is explored here by examining the intersection between this group of boys' perceptions of masculinity and their singing behaviours. Peer modelling was found to be an effective motivational ‘tool’ for improving singing behaviour and illustrates the importance of finding strategies to support boys' success in singing long before adolescence.
Experiments with a musical machine: musical style replication in 3 to 5 year old children
Authors: Addessi Anna Rita , Pachet François
Published: March 2005

The relationship between new technology and learning is gaining increasing relevance in the field of music education (Webster, 2002; Folkestad et al., 1998). However, only a few studies have considered the nature of the interaction between children and musical machines. This article describes an observation study of children aged 3–5 years confronting a particular interactive musical system, the Continuator, which is able to produce music in the same style as a human playing the keyboard (Pachet, 2003). The analysis of two case studies suggests that the Continuator is able to develop interesting child/machine interactions and creative musical processes in young children. It was possible to observe a ‘life cycle’ of interaction, as well as micro-processes similar to those observed in child/adult interactions (Stern, 1985; Imberty, 2002). The ability of the system to attract and hold the attention of children has been interpreted through Csikszentmihalyi's (1990) ‘flow theory’.
Modes of communication during jazz improvisation
Authors: Seddon Frederick A.
Published: March 2005

This study investigated modes of communication adopted by six student jazz musicians during rehearsal and performance. Six one-hour rehearsal sessions and a performance were observed and videotaped for analysis. Results revealed six modes of communication that formed two main categories, verbal and non-verbal, each containing three distinct modes of communication: instruction, cooperation and collaboration. Non-verbal collaborative mode displayed empathetic attunement, which is a vehicle for empathetic creativity. Empathetic creativity is a theoretical concept proposed by the author based on the concept of empathetic intelligence (Arnold, 2003, 2004). Practical applications of empathetic creativity are discussed with reference to music education, focusing on evaluation of individual contribution to group creative performances.
Addressing the concerns of conservatoire students about school music teaching
Authors: Mills Janet
Published: March 2005

While most of the students who graduate each year from the Royal College of Music (RCM) in London build performance-based portfolio careers that include some teaching, very few of them enter secondary school class music teaching. This article describes how young musicians' concerns about the career of secondary class music teacher develop as they move from sixth former to first year RCM undergraduate to third year undergraduate, and proposes some ways in which these concerns may be addressed. RCM students often agree strongly with statements consistent with a positive attitude to teaching, such as feeling a sense of achievement when pupils learn, and considering that teaching is about helping pupils realise their musical potential. However, they also tend to think that secondary class music teaching is not ‘doing music’. Successful secondary music teachers may take a different view, and the effect on RCM students of working with such teachers is reported descriptively.
Editorial
Authors: COX GORDON , PITTS STEPHANIE
Published: March 2005

In her contribution to our Special Issue in 2003, Estelle Jorgensen called for ongoing conversations between university lecturers and school teachers, to avoid the danger of music educators, historians and theorists being ‘like ships sailing past each other in the night’. We believe that one of the functions of BJME is to develop such collegial relationships and thus help to establish a strong music education community at all levels, both nationally and internationally. Certainly this present issue reflects a range of contexts from nursery schools to universities, with papers from researchers in Australia, England, France, Italy and Scotland.
Chronic tendon pathology: molecular basis and therapeutic implications
Authors: Riley Graham
Published: March 2005

Tendons are frequently affected by chronic pain or rupture. Many causative factors have been implicated in the pathology, which until relatively recently was under-researched and poorly understood. There is now a greater knowledge of the molecular basis of tendon disease. Most tendon pathology (tendinopathy) is associated with degeneration, which is thought to be an active, cell-mediated process involving increased turnover and remodelling of the tendon extracellular matrix. Degradation of the tendon matrix is mediated by a variety of metalloproteinase enzymes, including matrix metalloproteinases and ‘aggrecanases’. Neuropeptides and other factors released by stimulated cells or nerve endings in or around the tendon might influence matrix turnover, and could provide novel targets for therapeutic intervention.
Have concepts, will travel: analytical jurisprudence in a global context
Authors: Twining William
Published: March 2005

Our increasingly cosmopolitan discipline needs to be underpinned by a revival of the idea of general jurisprudence, in which generalisations – conceptual, normative, empirical, legal – about legal phenomena are treated as problematic. This paper argues that, as part of this, analytical jurisprudence should broaden its focus not only geographically, but also in respect of the range of concepts, conceptual frameworks, and discourses that it considers. How far is any of our current stock of concepts adequate for talking meaningfully across legal traditions and cultures? Which concepts ‘travel’ relatively well or badly and why? Such questions are illustrated with reference to discourses about legal rights, the treatment of prisoners, and corruption.
What Makes Modernity Late?
Authors: Winter Steven L.
Published: March 2005

There is a deep, if invisible conflict between our consumer culture and our democratic ideals. It is the result of social processes that, in the last half century, have profoundly transformed how we live and who we are. This paper explores the underpinnings of the condition that many identify as ‘late’ or ‘post’ modernity. Rather than focusing on the intellectual transformations wrought by the Enlightenment, it takes up Charles Taylor’s dialectical account of the relation between the social developments of modernity and changes in social understandings. It then considers the nature and import of our contemporary practices and conditions, their relation to the ‘postmodern’, and their implications both at home and abroad for the ability to sustain meaningful democracies under conditions of globalisation.
Führung im Ideenmanagement
Authors: Pundt Alexander , Schyns Birgit
Published: March 2005

Zusammenfassung. Psychologische Bedingungen für den Erfolg des Ideenmanagements wurden bislang kaum empirisch untersucht. Sowohl aus theoretischer wie auch aus praktischer Sicht wird dem Faktor Führung diesbezüglich eine wichtige Rolle zugeschrieben. In dieser Studie wurde der Frage nachgegangen, ob speziell transformationale Führung mit individuellen Beiträgen der Mitarbeiter zum Erfolg des Ideenmanagements in Verbindung steht. Dabei wurde der Erfolg des Ideenmanagements durch das individuelle Engagement der Mitarbeiter im Ideenmanagement operationalisiert. Eine Fragebogenuntersuchung wurde an einer heterogenen Stichprobe von N = 104 Mitarbeitern der verschiedensten Unternehmen durchgeführt. Es konnte ein positiver Zusammenhang zwischen inspirierender Motivierung, einer Komponente transformationaler Führung, und dem individuellen Engagement im Ideenmanagement nachgewiesen werden. Ferner konnte gezeigt werden, dass die Stärke des Zusammenhangs zwischen transformationaler Führung und dem individuellen Engagement im Ideenmanagement von der im Unternehmen vorherrschenden Verbesserungskultur moderiert wird. Entgegen den theoretischen Überlegungen zeigte sich kein signifikanter Zusammenhang zwischen intellektueller Stimulierung und dem individuellen Engagement im Ideenmanagement.
Akzeptanz von E-Learning in Unternehmen
Authors: Bürg Oliver , Mandl Heinz
Published: March 2005

Zusammenfassung. In den letzten Jahren gingen viele Unternehmen dazu über, ihre Mitarbeiter mit Hilfe von E-Learning zu schulen. Allerdings belegen aktuelle Untersuchungen eine unzureichende Akzeptanz im Sinne einer mangelnden Nutzung von E-Learning in Unternehmen. Diese Untersuchungen beantworten allerdings nicht die Frage, welche Faktoren die Mitarbeiterakzeptanz für E-Learning in Unternehmen fördern. In diesem Gebiet besteht ein Mangel an theoretisch fundierten Befunden. Um dem zu entgegnen, werden in diesem Beitrag das Task-Technology-Fit-Model ( Goodhue, 1995 ), das Technology-Acceptance-Model ( Davis, 1989 ) und das Technology-Acceptance-Model 2 ( Venkatesh & Davis, 2000 ) vor dem Hintergrund der Relevanz für die Akzeptanz von E-Learning in Unternehmen diskutiert. Ziel der Analyse der Akzeptanzmodelle ist es, personenbezogenene und Kontextfaktoren zu identifizieren, die einen Einfluss auf die Einstellungs- und Verhaltensakzeptanz ausüben. Diese Faktoren sind für zukünftige Untersuchungen in diesem Themengebiet zu beachten.
Polar mesosphere summer echoes (PMSE) at Halley (76°S, 27°W), Antarctica
Authors: Jarvis Martin J. , Clilverd Mark A. , Rose Mike C. , Rodwell Shane
Published: March 2005

Polar Mesosphere Summer Echoes (PMSE) are a pointer to summer mesospheric conditions and have fuelled the debate over temperature differences between the Antarctic and Arctic mesopause regions. However few PMSE observations have ever been made in Antarctica. We present initial PMSE observations from Halley (76°S, 27°W), taken during January and February 2004. These are the first observations at such high southern latitude, the first using a dynasonde for detection, and the first at 28 MHz. PMSE are frequently observed and exhibit a double maximum in diurnal occurrence in contrast to published observations at similar Arctic latitudes. The PMSE season ends slightly earlier, relative to summer solstice, than in the Arctic. The strength of the PMSE appear similar to PMSE observed in the northern hemisphere; this is consistent with published falling sphere measurements showing similar summer mesopause temperatures in January in the Antarctic as in July in the Arctic.
Earthquakes rupturing the Chelungpu fault in Taiwan are time predictable
Authors: Wang Jeen‐Hwa
Published: March 2005

On September 20, 1999, the Ms7.6 Chi‐Chi earthquake ruptured the Chelungpu fault in central Taiwan. The time predictable model is able to describe earthquakes rupturing the fault during the past 1900 years. The average recurrence periods and total slip rates are: 1900 years and 3.8 mm/yr for the northern segment of the fault and 630 years and 5.8 mm/yr for the southern one. About 30% strains, caused by tectonic loading, are released during failures of the fault.
Formation of the lunar wake in quasi‐neutral hybrid model
Authors: Kallio E.
Published: March 2005

We study the formation of the lunar wake by a quasi‐neutral hybrid (QNH) model. In the model ions are particles while electrons form a massless change neutralizing fluid. The model is three dimensional enabling us to study non‐axisymmetric filling of the tail with solar wind plasma resulting from non‐axisymmetric electromagnetic forces. We find that already a not fully kinetic QNH model can reproduce some of the basic observed features, namely (1) a long (over 10 lunar radii) tail of depleted plasma density, (2) enhanced magnetic field within the optical shadow and depressed magnetic field near the edge of the optical shadow and (3) non‐Maxwellian plasma beams with high temperature anisotropy. The analysis also supports previous studies which have emphasized the role of the direction of the magnetic field and kinetic effects in the lunar wake.
Composition of shelf methane seeps on the Cascadia Continental Margin
Authors: Collier Robert W. , Lilley Marvin D.
Published: March 2005

Methane reservoirs and seeps are an active component of the continental margin carbon budget and represent a poorly characterized pathway for reduced carbon cycling and methane input to the atmosphere. Active gas seeps from three shelf settings on the Cascadia Continental Margin off Oregon and Northern California contain nearly pure methane with a heavy carbon isotope composition (−29 to −35‰). An extensive study of the gas seep at Coquille Bank, Oregon, revealed a warm, buoyant pore fluid associated with the pockmark. As methane enters the water column above these seeps in a steady gas stream, a fraction escapes directly to the atmosphere while the balance dissolves into local seawater. Measured oxidation rates are too slow for significant local oxidation within the water column near the seep. Large mats of pink and white bacteria, including Beggiatoa spp. are found around the vent, demonstrating the activity of sulfide oxidizers in this ecosystem.
Using CHAMP radio occultation data to determine the top altitude of the Planetary Boundary Layer
Authors: von Engeln Axel , Teixeira João , Wickert Jens , Buehler Stefan A.
Published: March 2005

A simple approach to derive the Planetary Boundary Layer (PBL) top altitude from CHAMP (CHAllenging Minisatellite Payload) radio occultation (RO) data is presented. Our RO processing cuts off at an altitude, typically ≤4 km, below which the GPS signals are affected by tracking errors. This lowest processed altitude (LPA) is assumed to coincide with the PBL top. We average LPAs for the years 2001 to 2004 over 5 Degree latitude longitude boxes and compare them to ECMWF analysis data. The ECMWF PBL top was calculated from the relative humidity gradient with respect to altitude. Agreement between the data sets is good in terms of mean PBL height, especially over sea. The CHAMP data shows the major features of PBL height with a realistic transition from stratocumulus regions to shallow and deep cumulus areas. CHAMP also shows a substantial amount of PBL height variability that may prove useful to study PBL dynamics.
Detection of anomalous seismicity as a stress change sensor
Authors: Ogata Yosihiko
Published: March 2005

Anomalous seismicity such as quiescence and activation is defined by a systematic deviation of seismic activity from the predicted rate by the epidemic‐type aftershock sequence (ETAS) model that represents the normal occurrence rate of earthquakes in a region indicating the empirical triggering effect by the previous events. The model is fitted to a data set of origin times and magnitudes of earthquakes or aftershocks during May–August 2003 in and around northern Japan. The detected quiescence and activation relative to the predicted seismicity rate are consistent with the coseismic changes of Coulomb failure stress (CFS) in the corresponding regions, transferred from certain strong earthquakes. Few results in this paper agree with the claim that there should be a threshold value of ΔCFS capable of affecting seismic changes. Thus we expect that significant deviation of actual activity from the predicted rates is sensitive enough to detect a slight stress change. Furthermore, I offer a similar interpretation of the detected seismicity lowering relative to the modeled rates preceding the strong earthquakes, assuming some aseismic slips.
Mineral magnetic variation of the Jiaodao Chinese loess/paleosol sequence and its bearing on long‐term climatic variability
Authors: Deng Chenglong , Vidic Natasa J. , Verosub Kenneth L. , Singer Michael J. , Liu Qingsong , Shaw John , Zhu Rixiang
Published: March 2005

To retrieve reliable long‐term paleoclimatic signals from the Chinese loess/paleosol sequences deposited over the past 2.6 Myr, multiparameter mineral magnetic investigations have been conducted on the Jiaodao section on the Chinese central Loess Plateau. First, the lithogenic magnetic components and the pedogenic overprinting were chemically separated by the citrate‐bicarbonate‐dithionite (CBD) method. The magnetic properties of the least pedogenically altered loess units and post‐CBD loess/paleosols are dominated by coarse‐grained lithogenic magnetite. Increasing degree of pedogenesis increases both the concentration and grain size of pedogenic magnetite/maghemite. Long‐term changes of the pre‐CBD magnetic properties suggest a long‐term decrease in summer monsoon intensity and a long‐term increase in winter monsoon intensity from the late Pliocene to the late Pleistocene. Long‐term variations of the post‐CBD magnetic properties suggest an increase in both concentration and grain size of coarse‐grained lithogenic PSD/MD magnetite grains, and hence indicate a long‐term increase in winter monsoon intensity over that period. The coercivity decrease of the lithogenic component for the loess unit L15 may be related to the accelerated uplift of the Tibetan Plateau and its adjacent regions during the period of L15 deposition. From paleosol S5 to loess L1, higher values of coercivity of the lithogenic component occur in typical loess and paleosols, and lower values are found at the loess/paleosol transition. These coercivity variations are thought to be related to significant changes in the source region as well as dust deposition in the Loess Plateau caused by changes in ice/snow or vegetational cover. These new results lead to a better understanding of the relationships between the effects of tectonic, paleoclimatic, and paleoenvironmental processes in northwestern China.
Observed effects of horizontal radiative surface temperature variations on the atmosphere over a midwest watershed during CASES 97
Authors: Grossman Robert L. , Yates David , LeMone Margaret A. , Wesely M. L. , Song Jie
Published: March 2005

The association between ∼10‐km scale horizontal variation of radiometric surface temperature (Ts) and aircraft‐derived fluxes of sensible heat (H) and moisture (LE) is the focus of this work. We use aircraft, surface, and satellite data from a Cooperative Atmospheric‐Surface Exchange Studies (CASES) field program, which took place in the southern part of the 60 × 100 km Walnut River (Kansas) watershed from 22 April to 22 May 1997, when winter wheat matured and prairie grass greened up. Aircraft Ts observed along repeated flight tracks above the surface layer showed a persistent pattern: maxima over ridges characterized by shallow soil and rocky outcroppings and minima over riparian zones. H and Ts reached maxima in the same longitude zone on two flight tracks 40 km apart. Satellite Ts data from March to June reveal similar persistent patterns with minima more persistent than maxima. Two mechanisms are suggested to explain the association of H and Ts maxima: (1) for winds between 6 and 8 ms−1, modulation of the surface energy budget by vegetation effects; or (2) for winds equal to or below 4 ms−1, a thermally driven circulation centered on Ts maxima. Both mechanisms were possibly enhanced by increased static instability over the Ts maxima. Owing to the small sample available, these results are suggestive rather than conclusive. Effects of rainfall and vegetation on watershed‐scale Ts gradients are also explored.
Evaluation of regional cloud feedbacks using single‐column models
Authors: Del Genio Anthony D. , Wolf Audrey B. , Yao Mao‐Sung
Published: March 2005

Cloud feedbacks in a warmer climate have not yet been constrained by models or observations. We present an approach that combines a general circulation model (GCM), single‐column model (SCM), satellite and surface remote sensing data, and analysis product to infer regional cloud feedbacks and evaluate model simulations of them. The Atmospheric Radiation Measurement (ARM) Program Southern Great Plains (SGP) continuous forcing product, derived from a mesoscale analysis constrained by top‐of‐atmosphere and surface data, provides long‐term advective forcing that links the models to the data. We drive an SCM with the continuous forcing for 10 cold season months in which synoptic forcing dominates the meteorology. Cloud feedbacks in midlatitude winter are primarily responses to changes in dynamical forcing. Thus we select times when observed advective forcing anomalies resemble doubled CO2 advective forcing changes in the parent GCM. For these times we construct cloud type anomaly histograms in the International Satellite Cloud Climatology Project and Active Remotely Sensed Cloud Locations data sets and simulated versions of these histograms in the SCM. Comparison of the SCM subset to GCM doubled CO2 cloud type changes tells us how relevant the selected times are to the GCM's cloud feedbacks, while comparisons of the SCM to the data tell us how well the model performs in these situations. The data suggest that in midlatitude winter, high thick clouds should increase while cirrus and low clouds decrease in upwelling regimes in a climate warming. Downwelling regime cloud feedbacks are dominated by changes in low clouds but are not as well constrained by the data.
U series disequilibria: Insights into mantle melting and the timescales of magma differentiation
Authors: Peate David W. , Hawkesworth Chris J.
Published: March 2005

Several U series nuclides have half‐lives (230Th, 76 kyr; 231Pa, 33 kyr; and 226Ra, 1.6 kyr) comparable to timescales of magmatic processes. We review the basic principles of extracting time information from U series nuclides and summarize variations in (230Th/238U), (226Ra/230Th), and (231Pa/235U) observed in magmas from mid‐ocean ridges, within‐plate settings, and subduction zones to contrast melt generation processes in different tectonic settings. U series disequilibria on melt and crystal phases of igneous rocks can provide temporal information on different stages in the magmatic history (melting duration, melt transport rates, magmatic crustal residence times, and timing of crystal growth) and potentially provide clues about the nature and mineralogy of mantle sources, mantle upwelling rates and porosity, fluid influences, and mechanisms of melt generation and transport. The subject is beginning to take a genuinely integrated approach to developing physically realistic quantitative models that offer increasingly exciting opportunities in the study of magmatic processes.
Retrieving sea surface salinity with multiangular L‐band brightness temperatures: Improvement by spatiotemporal averaging
Authors: Camps A. , Vall‐llossera M. , Batres L. , Torres F. , Duffo N. , Corbella I.
Published: March 2005

The Soil Moisture and Ocean Salinity (SMOS) mission was selected in May 1999 by the European Space Agency to provide global and frequent soil moisture and sea surface salinity maps. SMOS' single payload is Microwave Imaging Radiometer by Aperture Synthesis (MIRAS), an L band two‐dimensional aperture synthesis interferometric radiometer with multiangular observation capabilities. Most geophysical parameter retrieval errors studies have assumed the independence of measurements both in time and space so that the standard deviation of the retrieval errors decreases with the inverse of square root of the number of measurements being averaged. This assumption is especially critical in the case of sea surface salinity (SSS), where spatiotemporal averaging is required to achieve the ultimate goal of 0.1 psu error. This work presents a detailed study of the SSS error reduction by spatiotemporal averaging, using the SMOS end‐to‐end performance simulator (SEPS), including thermal noise, all instrumental error sources, current error correction and image reconstruction algorithms, and correction of atmospheric and sky noises. The most important error sources are the biases that appear in the brightness temperature images. Three different sources of biases have been identified: errors in the noise injection radiometers, Sun contributions to the antenna temperature, and imaging under aliasing conditions. A calibration technique has been devised to correct these biases prior to the SSS retrieval at each satellite overpass. Simulation results show a retrieved salinity error of 0.2 psu in warm open ocean, and up to 0.7 psu at high latitudes and near the coast, where the external calibration method presents more difficulties.
Laboratory evaluation of time domain reflectometry for continuous monitoring of stream stage, channel profile, and aqueous conductivity
Authors: Tidwell Vincent C. , Brainard James R.
Published: March 2005

Time domain reflectometry (TDR) operates by propagating a radar frequency electromagnetic pulse down a transmission line while monitoring the reflected signal. As the electromagnetic pulse propagates along the transmission line, it is subject to impedance by the dielectric properties of the media along the transmission line (e.g., air, water, and sediment), reflection at dielectric discontinuities (e.g., air‐water or water‐sediment interface), and attenuation by electrically conductive materials (e.g., salts and clays). Taken together, these characteristics provide a basis for integrated stream monitoring, specifically, concurrent measurement of stream stage, channel profile, and aqueous conductivity. Requisite for such application is a means of extracting the desired stream parameters from measured TDR traces. Analysis is complicated by the fact that interface location and aqueous conductivity vary concurrently and multiple interfaces may be present at any time. For this reason a physically based multisection model employing the S11 scatter function and Debeye parameters for dielectric dispersion and loss is used to analyze acquired TDR traces. Here we explore the capability of this multisection modeling approach for interpreting TDR data acquired from complex environments, such as encountered in stream monitoring. A series of laboratory tank experiments was performed in which the depth of water, depth of sediment, and conductivity were varied systematically. Comparisons between modeled and independently measured data indicate that TDR measurements can be made with an accuracy of ±3.4 × 10−3 m for sensing the location of an air‐water or water‐sediment interface and ±7.4% of actual for the aqueous conductivity.
Impulsive solar energetic ion trapping in the magnetosphere during geomagnetic storms
Authors: Kress B. T. , Hudson M. K. , Slocum P. L.
Published: March 2005

A mechanism for prompt trapping of solar energetic particles (SEPs) in the inner magnetosphere during severe storms is numerically demonstrated. The mechanism can be understood in terms of a generalization of Störmer theory to a time dependently perturbed dipole magnetic field. Test particle Lorentz trajectories are computed in fields from a Lyon‐Feder‐Mobarry (LFM) global MHD magnetospheric model simulation of the 24 Nov 2001 storm to show energetic particles may be impulsively injected into the magnetosphere and trapped on a time scale of minutes by a sudden compression and de‐compression of the magnetosphere. It is also shown that SEPs with access to the innermost L‐shells enter through the magnetopause on the day side.
Monodomain critical radius for soft-magnetic fine particles
Authors: Kákay Attila , Varga L. K.
Published: March 2005

Remanent states of spherelike particles have been investigated for different ferromagnetic metallic materials by numerical micromagnetic calculations in order to establish the critical radius for monodomain-vortex transition. Critical radii have been compared with those obtained earlier by order-of-magnitude estimates and analytical micromagnetic calculations. A hard-axis-oriented vortex state has been found as a transition between the monodomain and easy-axis-oriented vortex magnetization states.
Noncontacting laser photocarrier radiometric depth profilometry of harmonically modulated band bending in the space-charge layer at doped SiO2-Si interfaces
Authors: Mandelis Andreas , Batista Jerias , Gibkes Jürgen , Pawlak Michael , Pelzl Josef
Published: March 2005

Laser infrared photocarrier radiometry (PCR) was used with a harmonically modulated low-power laser pump and a superposed dc superband-gap optical bias (a secondary laser beam) to control and monitor the space-charge-layer (SCL) width in oxidized p-Si–SiO2 and n-Si–SiO2 interfaces (wafers) exhibiting charged interface-state related band bending. Applying the theory of PCR-SCL dynamics [A. Mandelis, J. Appl. Phys. 97, 083508 (2005)] to the experiments yielded various transport parameters of the samples as well as depth profiles of the SCL exhibiting complete ( p-type Si) or partial (n-type Si) band flattening, to a degree controlled by widely different minority-carrier capture cross section at each interface. The uncompensated charge density at the interface was also calculated from the theory.
Theory of space-charge layer dynamics at oxide-semiconductor interfaces under optical modulation and detection by laser photocarrier radiometry
Authors: Mandelis Andreas
Published: March 2005

The dynamic theory of the optically modulated space-charge layer (SCL) resulting from band bending at a Si–SiO2 interface was developed in terms of the density of interface charges occupying band-gap energy states. Expressions were derived for these interface charge densities, interacting with the free-carrier density wave generated in the SCL and in the quasineutral region (bulk) by an intensity-modulated super-band-gap laser. The residual and modulated interface charge coverage affects the band-edge-to-impurity state recombination and the concomitant near-infrared photon emission comprising the photocarrier radiometry (PCR) signal. The PCR theory incorporating these effects was further developed. It was found to involve the dc, fundamental, and entire harmonic spectrum of the excitation frequency as a result of the optical modulation of the curvature of the energy bands and the SCL width at the interface.
Linear scaling computation of the Fock matrix. VII. Periodic density functional theory at the Γ point
Authors: Tymczak C. J. , Challacombe Matt
Published: March 2005

Linear scaling quantum chemical methods for density functional theory are extended to the condensed phase at the Γ point. For the two-electron Coulomb matrix, this is achieved with a tree-code algorithm for fast Coulomb summation [M. Challacombe and E. Schwegler, J. Chem. Phys. 106, 5526 (1997)], together with multipole representation of the crystal field [M. Challacombe, C. White, and M. Head-Gordon, J. Chem. Phys. 107, 10131 (1997)]. A periodic version of the hierarchical cubature algorithm [M. Challacombe, J. Chem. Phys. 113, 10037 (2000)], which builds a telescoping adaptive grid for numerical integration of the exchange-correlation matrix, is shown to be efficient when the problem is posed as integration over the unit cell. Commonalities between the Coulomb and exchange-correlation algorithms are discussed, with an emphasis on achieving linear scaling through the use of modern data structures. With these developments, convergence of the Γ-point supercell approximation to the k-space integration limit is demonstrated for MgO and NaCl. Linear scaling construction of the Fockian and control of error is demonstrated for RBLYP∕6-21G* diamond up to 512 atoms.
Millimeter wave spectrum of bromomethyl radical, CH2Br
Authors: Bailleux Stéphane , Dréan Pascal , Zelinger Zdeněk , Civiš Svatopluk , Ozeki Hiroyuki , Saito Shuji
Published: March 2005

The rotational spectra of the two isotopic species of the bromomethyl radical, CH2Br79 and CH2Br81, have been observed in their ground electronic state B12 in the 180–470 GHz frequency region, corresponding to a-type transitions from N=8−7 to N=21−20. The radical was produced by hydrogen abstraction of methylbromide (CH3Br) either by chlorine or by fluorine atoms in a free space cell. Hyperfine structure due to the bromine nucleus has been resolved in the observed spectra, and the rotational constants as well as the fine and hyperfine interaction constants were accurately determined for both isotopomers. The inertial defect was determined to be 0.028 96(20) and 0.02895(20)amuÅ2, for CH2Br79 and CH2Br81, respectively, suggesting a planar structure. By fixing the ∠HCH bond angle at 124.5°, an effective molecular structure can be derived as r0(CBr)=1.848Å and r0(CH)=1.084Å. A comparison of the molecular structure of various halogen-substituted methyl radicals with respect to the planarity of these radicals is discussed.
Ionization potentials of large sodium doped ammonia clusters
Authors: Steinbach C. , Buck U.
Published: March 2005

In a continuous neat supersonic expansion ammonia clusters are generated and doped with sodium atoms in a pickup cell. Thus clusters of the form Na(NH3)n are produced that are photoionized by a tunable dye laser system. The ions are mass analyzed in a reflectron time-of-flight mass spectrometer, and the wavelength dependent ion signals serve for the determination of the ionization potentials (IP) of the different clusters in the size range 10⩽n⩽1500. Aside from a plateau for 10⩽n⩽17 and smaller steps at n=24, 35, and 59 on the average a continuous decrease of the IP with cluster size is observed. The IPs in this size range are linear with (n+1)−1∕3 and extrapolate to IP(n=∞)=1.66±0.01eV. The slope is consistent with a dielectric continuum model of the solvated electron and the dielectric constant of the solid. The extrapolated IPs are compared with results obtained for negative ammonia cluster ions and metallic solutions in liquid ammonia. Differences are explained by the presence of counterions and their various distances from the solvated electron.
How to choose one-dimensional basis functions so that a very efficient multidimensional basis may be extracted from a direct product of the one-dimensional functions: Energy levels of coupled systems with as many as 16 coordinates
Authors: Dawes Richard , Carrington Tucker
Published: March 2005

In this paper we propose a scheme for choosing basis functions for quantum dynamics calculations. Direct product bases are frequently used. The number of direct product functions required to converge a spectrum, compute a rate constant, etc., is so large that direct product calculations are impossible for molecules or reacting systems with more than four atoms. It is common to extract a smaller working basis from a huge direct product basis by removing some of the product functions. We advocate a build and prune strategy of this type. The one-dimensional (1D) functions from which we build the direct product basis are chosen to satisfy two conditions: (1) they nearly diagonalize the full Hamiltonian matrix; (2) they minimize off-diagonal matrix elements that couple basis functions with diagonal elements close to those of the energy levels we wish to compute. By imposing these conditions we increase the number of product functions that can be removed from the multidimensional basis without degrading the accuracy of computed energy levels. Two basic types of 1D basis functions are in common use: eigenfunctions of 1D Hamiltonians and discrete variable representation (DVR) functions. Both have advantages and disadvantages. The 1D functions we propose are intermediate between the 1D eigenfunction functions and the DVR functions. If the coupling is very weak, they are very nearly 1D eigenfunction functions. As the strength of the coupling is increased they resemble more closely DVR functions. We assess the usefulness of our basis by applying it to model 6D, 8D, and 16D Hamiltonians with various coupling strengths. We find approximately linear scaling.
Achieving fast oxygen diffusion in perovskites by cation ordering
Authors: Taskin A. A. , Lavrov A. N. , Ando Yoichi
Published: March 2005

The oxygen-exchange behavior has been studied in half-doped manganese and cobalt perovskite oxides. We have found that the oxygen diffusivity in Gd0.5Ba0.5MnO3−δ can be enhanced by orders of magnitude by inducing crystallographic ordering among lanthanide and alkali-earth ions in the A-site sublattice. Transformation of a simple cubic perovskite, with randomly occupied A sites, into a layered crystal GdBaMn2O5+x (or isostructural GdBaCo2O5+x for cobalt oxide) with alternating lanthanide and alkali-earth planes reduces the oxygen bonding strength and provides disorder-free channels for ion motion, pointing to an efficient way to design new ionic conductors.
Dynamics of propene adsorption on Ag(001)
Authors: Gerbi A. , Vattuone L. , Savio L. , Rocca M.
Published: March 2005

The interaction of propene with Ag(001) is investigated by high resolution electron energy loss spectroscopy and supersonic molecular beam methods under ultra high vacuum conditions. Propene adsorbs molecularly at 110K and desorbs intact leaving a clean surface after annealing to 160K. Two adsorption sites, characterized by slightly different vibrational modes, exist. The low frequency species is observed already at low coverage for molecules impinging at strongly hyperthermal energies while at lower translational energy it appears only at high coverage. The initial sticking probability S0 decreases with increasing translational energy, as appropriate for nonactivated adsorption systems. The angle and energy dependence of S0 indicate that scaling is intermediate between total and normal energy. From the coverage dependence of the sticking probability we infer that both a nonthermal intrinsic and a thermal extrinsic precursor exist.
Structure and stability of chiral β-tapes: A computational coarse-grained approach
Authors: Bellesia Giovanni , Fedorov Maxim V. , Kuznetsov Yuri A. , Timoshenko Edward G.
Published: March 2005

We present two coarse-grained models of different levels of detail for the description of β-sheet tapes obtained from equilibrium self-assembly of short rationally designed oligopeptides in solution. Here we only consider the case of the homopolymer oligopeptides with the identical sidegroups attached, in which the tapes have a helicoid surface with two equivalent sides. The influence of the chirality parameter on the geometrical characteristics, namely the diameter, interstrand distance, and pitch, of the tapes has been investigated. The two models are found to produce equivalent results suggesting a considerable degree of universality in conformations of the tapes.
Electric-field dependence of negative-bias temperature instability
Authors: Ushio Jiro , Okuyama Yutaka , Maruizumi Takuya
Published: March 2005

To investigate the origin of the electric-field dependence of negative-bias temperature instability (NBTI), we calculated the change in the activation energies of the dissociation reaction of a Si–H bond caused by an electric field. The calculated activation energies show that the change is too small to explain previously reported experimental electric-field dependence. On the other hand, a hole generated by the electric field in the silicon/gate-dielectric interface reduces the activation energy much more. We propose a NBTI mechanism based on the calculated activation energies. This mechanism can be applied to estimate NBTI lifetime over a wide range of electric fields.
Bendable single crystal silicon thin film transistors formed by printing on plastic substrates
Authors: Menard E. , Nuzzo R. G. , Rogers J. A.
Published: March 2005

Bendable, high performance single crystal silicon transistors have been formed on plastic substrates using an efficient dry transfer printing technique. In these devices, free standing single silicon objects, which we refer to as microstructured silicon (μs-Si), are picked up, using a conformable rubber stamp, from the top surface of a wafer from which they are generated. The μs-Si is then transferred, to a specific location and with a controlled orientation, onto a thin plastic sheet. The efficiency of this method is demonstrated by the fabrication of an array of thin film transistors that exhibit excellent electrical properties: average device effective mobilities, evaluated in the linear regime, of ∼240cm2∕Vs, and threshold voltages near 0V. Frontward and backward bending tests demonstrate the mechanical robustness and flexibility of the devices.