bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of tanshinones in the roots of Salvia miltiorrhiza (Dan‐shen) by high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry
Authors: Yang Min , Liu Aihua , Guan Shuhong , Sun Jianghao , Xu Man , Guo Dean
Published: March 2006

The qualitative analysis of tanshinones in the roots of Salvia miltiorrhiza (Dan‐shen in Chinese) was performed using high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry (ESI‐MSn). Tanshinones are the major bioactive constituents of Dan‐shen, which is used in China for the treatment of haematological abnormalities and cardiovascular diseases. The ESI‐MSn fragmentation behavior of tanshinones was investigated. For tanshinones with the tanshinone I nucleus, the fragmentation was triggered by loss of a molecule of CO except bearing a substituent at C17 or C18, followed by sequential eliminations of CO. If C15–16 was a saturated bond, the fragmentation was triggered by elimination of a molecule of H2O. For tanshinones with the tanshinone IIA nucleus, the fragmentation was triggered by loss of a molecule of H2O, followed by successive eliminations of CO. Ions corresponding to loss of a molecule of propylene (Δm = 42) were also observed. Moreover, when C15–16 was a saturated bond, ions corresponding to losses of CH3, H2O and propylene were more abundant. If no D‐ring existed, the presence of isopropyl resulted in an elimination of a molecule of H2O with an adjacent CO or OH. In addition, the extension of the π‐conjugation in the A‐ring (especially at C1–2) induced the fragmentation by loss of a molecule of CO. These fragmentation rules were applied to the identification of tanshinones in a chloroform/methanol (3:7) extract of Dan‐shen, which was separated on a C18 column with gradient elution. A total of 27 tanshinones were identified, including five new constituents. The established method could be used for the sensitive and rapid identification of tanshinones in the Dan‐shen drug and its pharmaceutical preparations. Copyright © 2006 John Wiley & Sons, Ltd.
Use of gas chromatography/mass spectrometry with positive chemical ionization for the determination of opiates in human oral fluid
Authors: Cámpora Pamela , Bermejo Ana María , Tabernero María Jesús , Fernández Purificación
Published: March 2006

An analytical method for the simultaneous determination of codeine, morphine and 6‐acetylmorphine (6AM) in human oral fluid was developed. The method involves liquid‐liquid extraction in Toxitubes A®, derivatization with 99:1 (v/v) N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS), and gas chromatography/mass spectrometry with positive chemical ionization (GC/PCI‐MS) determination. The detector response was linear over the concentration range 30–500 ng/mL with coefficients of correlation higher than 0.99. The precision was acceptable with coefficients of variation less than 7.5%. The limits of detection achieved were 0.7 ng/mL for codeine, 2.0 ng/mL for morphine, and 0.6 ng/mL for 6AM. The method proposed was applied to 80 oral fluid samples from opiates users, 98% of which were positive for the three analytes. Human oral fluid is a suitable biological fluid for the determination of opiates by GC/PCI‐MS. Copyright © 2006 John Wiley & Sons, Ltd.
Development of mobile broadband interactive satellite access system for Ku/Ka band
Authors: Song Yun‐Jeong , Kim Pan‐Soo , Oh Deock‐Gil , Jeon Soon‐Ik , Lee Ho‐Jin
Published: March 2006

It is difficult to implement the broadband satellite Internet and broadcasting service for mobile environment. The paper presents the design and implementation of a mobile broadband satellite access system. In case of the system design, mobile terminal service is considered a critical factor than fixed terminal services, such as resource management, antenna tracking, weak signal recovery. In the paper, mobile broadband interactive satellite access technology system (MoBISAT) is presented. The system network, which is composed of a star network, consists of time division multiplexing‐based forward link and multi‐frequency time division multiple access‐based return link. The MoBISAT provides both Ku‐band satellite TV and Ka‐band high‐speed Internet base on DVB‐S/DVB‐RCS standards to the passengers and crews for land, maritime and air vehicles. The key factors of hub and mobile terminal are addressed for the design and implementation of the MoBISAT. Especially, the design and implementation of the return link demodulation method, resource management scheme and mobile terminal structure including mobile antenna are described. Copyright © 2006 John Wiley & Sons, Ltd.
A DVB/Inmarsat hybrid architecture for asymmetrical broadband mobile satellite services
Authors: Andersen Bjørn Roger , Gangaas Odd , Andenæs Jens
Published: March 2006

In order to bridge the gap, both regulatory and technologically, between offering mobile satellite services at L‐band today and broadband mobile services at C‐band, Ku‐band or Ka‐band in the future, a short‐term solution is foreseen. Therefore, a DVB/Inmarsat hybrid service offering bi‐directional asymmetrical satellite connectivity, with a broadband receive channel at Ku‐band based on DVB‐S, and with a transmit channel at L‐band based on Inmarsat Mobile Packet Data Service, has successfully been developed, implemented and tested. The article focuses on the rationale for, and a technical solution, and how this can be evolved to support use of Inmarsat Broadband Global Area Access as transmit channel at L‐band. There are no regulatory issues associated with global operation of such a system, and the users can access the services using cost‐efficient off‐the‐shelf equipment, since the well established Inmarsat and DVB standards are utilized. The system has proved its feasibility to offer services like Internet access, email access, fast file transfers, and IP streaming of audio and video, in addition to the traditional Inmarsat services. Copyright © 2006 John Wiley & Sons, Ltd.
Ku‐mobile: satellite multimedia services for cars in the Ku‐band
Authors: Scalise Sandro , Ernst Harald , Hack Thomas , Loeillet Christophe , Midthassel Rolv
Published: March 2006

Satellite radio for vehicles is normally hampered by the problem of the shadowing of the line of sight between satellite and receiver. In this paper, a personalized radio concept is proposed as an alternative to the streaming approach used for traditional radio: instead of transmitting a number of distinct continuous streams, individual audio and multimedia files are broadcasted.

The received files are stored in a large cache located in the receiver of each mobile terminal. There, the files are sequentially played from the cache to generate a service similar to traditional radio/entertainment programs. This assembled program may depends on some user settings and does depend on the available files, which in turn depend on the reception conditions of each individual user. A continuous connection between the satellite and each receiver is therefore no longer required. Instead, it is sufficient to ensure that enough new files to generate an attractive program are available in the cache. Therefore, the aim is to reach a sufficiently high update rate for the content of the cache. A failure in the transfer of an individual file has no impact on the audible quality, since the only effect is that this file cannot be used when assembling the program.

Besides its robustness, this approach opens new possibilities in terms of enhanced services, like the capability to skip or repeat part of the radio program, and to easily integrate additional data services like e.g. road and weather maps distribution or generic html content. Furthermore, this approach can be combined with the usage of satellite systems with low link margins, which are already available, for instance in the Ku‐band. This results in low infrastructure costs for the deployment of such a system, together with the availability of new, personalized attractive features. An overview about the dedicated communication system being developed to support the novel concept presented above, including the status of an end‐to‐end demonstrator, will be given. Copyright © 2006 John Wiley & Sons, Ltd.
On the use of OFDM radio interface for satellite digital multimedia broadcasting systems
Authors: Cioni S. , Corazza G. E. , Neri M. , Vanelli‐Coralli A.
Published: March 2006

The paper considers the application of Orthogonal Frequency Division Multiplexing (OFDM) techniques in the physical layer of a satellite system devoted to the provision of digital multimedia broadcasting (DMB) services, which are presently the focus of extensive research and development endeavours. In particular, the paper demonstrates that the inherently high spectrum efficiency of OFDM can be retained even in unfavourable propagation channels affected by heavy non‐linear distortion introduced by the on‐board high power amplifier. This encouraging performance is achieved through the proper design and application of coding and pre‐distortion techniques, as described in the paper. Based on these results, the paper considers also the comparison of OFDM and High Speed Downlink Packet Access (HSDPA) techniques. HSDPA is the standardized radio interface for 3G terrestrial mobile networks. Copyright © 2006 John Wiley & Sons, Ltd.
A laboratory for public scholarship and democracy
Authors: Cohen Jeremy
Published: March 2006

The founder of Penn State's Laboratory for Public Scholarship and Democracy and chair of Penn State's Public Scholarship Associates establishes public scholarship's connections with democracy by distinguishing public scholarship from service, outlining a curriculum of consequence, and suggesting the constitutional roots of public scholarship.
Individual and organizational influences on faculty members' engagement in public scholarship
Authors: Colbeck Carol L. , Wharton‐Michael Patty
Published: March 2006

This chapter proposes a conceptual framework for understanding influences on faculty work and for conducting research about individual, organizational, and epistemological factors that may shape faculty members' engagement in public scholarship.
Rhetorics of public scholarship: Democracy, Doxa, and the human barnyard
Authors: Eberly Rosa A.
Published: March 2006

Drawing on ancient and contemporary connections between rhetoric—an art of public deliberation and communication—and democracy, this chapter argues for creating “a common space of public scholarship across and beyond disciplines” to help ensure the future of sustainable publics and participatory democracy.
Public scholarship and youth at the transition to adulthood
Authors: Flanagan Constance
Published: March 2006

Informed by an interdisciplinary body of scholarship yet focusing on developmental challenges and competencies of the young adult years, this chapter argues that public scholarship is the best form of education for young adults in democracies.
An explication of public scholarship objectives
Authors: Wharton‐Michael Patty , Janke Emily M. , Karim Rehnuma , Syvertsen Amy K. , Wray Laura D.
Published: March 2006

As a baseline for evaluation and assessment, an interdisciplinary cohort of graduate students collaboratively identifies and explicates the central concepts and objectives of public scholarship in this chapter.
Public scholarship in the postmodern university
Authors: Yapa Lakshman
Published: March 2006

This chapter argues that public scholarship can transcend the epistemological limitations of research universities by drawing on postmodern social theory and pragmatism in order to help solve social problems that too often expert knowledge itself has helped create.
Public scholarship: Making sense of an emerging synthesis
Authors: Ramaley Judith A.
Published: March 2006

This concluding chapter, written by a national leader in higher education, reflects on public scholarship from a perspective beyond Penn State and argues that public scholarship promises to strengthen “that special form of public decision making that we call democracy.”
Genotypic and phenotypic variability in cowpea grown in a humid environment in Nigeria
Authors: Nwofia GE , Ene‐Obong EE , Okocha PI
Published: March 2006

From a study of 108 cowpea genotypes, plant height, dry matter yield, pod length and seeds/pod could be improved by direct selection and these are associated with seed yield. Copyright © 2006 John Wiley & Sons, Ltd
Procedure compilation in the refinement calculus
Authors: Lermer K. , Fidge C. J.
Published: March 2006

High-level language program compilation strategies can be proven correct by modelling the process as a series of refinement steps from source code to a machine-level description. We show how this can be done for programs containing recursively-defined procedures in the well-established predicate transformer semantics for refinement. To do so the formalism is extended with an abstraction of the way stack frames are created at run time for procedure parameters and variables.
No Matter How Hard You Try, Your Feet Still Get Wet: Insider and Outsider Perspectives on Bridging Diversity
Authors: Brodsky Anne E. , Faryal Tahmeena
Published: March 2006

Research in which the researcher and the participants come from different contexts and communities always presents challenges. This paper is based on qualitative, community‐based research carried out by a U.S. researcher in Pakistan and Afghanistan with an underground Afghan women's humanitarian and political organization. Written from the perspectives of two authors, one an organization insider and the other the outside researcher, it presents some unique examples of diversity challenges, while also illuminating issues that exist in subtle ways even in more common research experiences. Within the context of multiple diversities, two challenges to bridging diversity are discussed: (1) Can or should all diversities be bridged? and (2) Can narrow attention to diversity lead to ignoring similarities? We argue that the definitions of success and failure in bridging diversity are themselves relative terms, grounded in this very diversity. Further, even when research fails to bridge diversity it may, in fact, not only honor and respect that diversity, but ultimately lead to a better understanding of it.
Stem turnover strategy of multiple‐stemmed woody plants
Authors: Fujiki Daisuke , Kikuzawa Kihachiro
Published: March 2006

We have investigated stem turnover strategy for Lindera umbellata, an understory shrub that sprouts from its rootstock under natural conditions to replace constituent stems, on the basis of the hypothesis that the multiple‐stemmed form of woody species is an adaptation enabling efficient reproduction in high‐stress environments. We tested the hypothesis that the timing of stem replacement maximizes sexual reproduction for the shrub. We developed a model for the time of optimum replacement of a stem by a daughter stem which maximizes the sexual reproduction of a shrub and tested the model using L. umbellata growing in the field. From the model, the optimum time of replacement of a stem with a daughter stem is when cumulative sexual reproduction per unit time for the stem is maximum. In practice, this will be the last age (topt) at which annual sexual reproduction in a stem can potentially exceed cumulative sexual reproduction per unit time for the stem. Half of the stems died at almost topt and had sexually mature daughter stems at that time. Other stems, however, died at times more remote from topt when daughter stems were sexually immature. It is thought that normal replacement of the latter stems was prevented by accidents such as breakage. We conclude that clumps of L. umbellata achieve efficient sexual reproduction by stem replacement at the optimum time, although accidents can, to some extent, determine when the stem actually dies.
Interactions between humans and leopard seals
Authors: Muir Shona F. , Barnes David K.A. , Reid Keith
Published: March 2006

In July 2003 Kirsty Brown, a marine biologist at Rothera Research Station (West Antarctic Peninsula), was attacked and drowned by a leopard seal (Hydrurga leptonyx). As a direct consequence, a study was initiated to analyse interactions between humans and leopard seals over the last thirty years utilising humanistic and observational data. The response of leopard seals to humans in different situations was considered using a categorical response scale. Location of the leopard seal and human had the greatest influence on the response of the leopard seal. More specifically, interactions occurring at the ice edge, where leopard seals seek out prey, resulted in the highest response from leopard seals. ‘In water’ interactions, examined through SCUBA dive and snorkelling logs, generally described the seal’s behaviour as displaying curiosity and occurred most frequently at the surface. Although leopard seals approached close to observers and displayed behaviour that appeared aggressive, there were no records of interactions where ‘curious’ leopard seals showed subsequent hunting, or attack behaviour. In contrast, in most interactions (only a few occasions) where physical contact was initiated by a seal, in the form of an attack, the seal was not seen prior to the attack. Kirsty’s incident is the only known account of its kind, given that physical contact occurred at the surface of the water, and the seal had not been seen prior to the attack. This suggests that the commonly cited descriptions of leopard seals interacting with humans in the water are a distinctly different behaviour to that displayed in the attack on Kirsty. Although leopard seal behaviour was generally described by divers as curious, the death of Kirsty Brown indicates that leopard seals can display predatory behaviour towards humans.
The occurrence of lead in the bone tissues of Trematomus bernacchii, Terra Nova Bay, Ross Sea
Authors: Riva Simona Dalla , Abelmoschi Maria Luisa , Grotti Marco , Soggia Francesco , Bottaro Massimiliano , Vacchi Marino
Published: March 2006

The occurrence of lead in various bone tissues of Trematomus bernacchii was investigated in order to identify the optimal target tissue and to examine potential relationships between bone lead concentration and fish size and age. Lead concentration values found in vertebrae and jaws (0.44 ± 0.13 and 0.41 ± 0.09 μg g−1 of dry weight tissue, respectively) were significantly higher than those in the other bones examined (otoliths, branchiostegal rays and pectoral girdles), indicating a preferential accumulation of lead in these tissues. Hence, vertebrae and jaws were selected as suitable target organs. The significance of T. bernacchii as a marker of lead bio-availability for the marine environment was tested by comparing data with the ones obtained for the Scorpaena notata, a benthic fish living in the more polluted coasts of the Mediterranean Sea, and by correlating the lead content found in the fish bones with the concentration of bio-available lead in the marine sediments on which the two fishes live. Bio-availability was evaluated by solid speciation and size fractionation techniques. All data clearly indicated that the difference in bone lead content between S. notata and T. bernacchii (0.83 ± 0.17 μg g−1 and 0.42 ± 0.08 μg g−1, significant at the 99.9% confidence level) can be ascribed to the concentration of bio-available lead in their respective environment. Finally, no correlation between the lead accumulation in bone tissues and fish size and age was found for either fish species.
Insights into the immunopathogenesis of malaria using mouse models
Authors: Lamb Tracey J. , Brown Douglas E. , Potocnik Alexandre J. , Langhorne Jean
Published: March 2006

Malaria kills approximately 1–2 million people every year, mostly in sub-Saharan Africa and in Asia. These deaths are at the most severe end of a scale of pathologies affecting approximately 500 million people per year. Much of the pathogenesis of malaria is caused by inappropriate or excessive immune responses mounted by the body to eliminate malaria parasites. In this review, we examine the evidence that immunopathology is responsible for malaria disease in the context of what we have learnt from animal models of malaria. In particular, we look in detail at the processes involved in endothelial cell damage leading to syndromes such as cerebral malaria, as well as generalised systemic manifestations such as anaemia, cachexia and problems with thermoregulation of the body. We also consider malaria in light of the variation of the severity of disease observed among people, and discuss the contribution from animal models to our understanding of this variation. Finally, we discuss some of the implications of immunopathology, and of host and parasite genetic variation, for the design and implementation of anti-malarial vaccines.
The Barroso Drama Enhancing Parliamentary Control Over the European Commission and the Member States
Authors: Beukers Thomas
Published: March 2006

Appointment and Censure of the European Commission — Development of Rules of Constitutional Practice — Parliamentary committee hearings 2004 — Guidelines on Approval Procedure of the Commission — Framework Agreement 2005 between European Parliament and Commission — Clash between Parliament and Council on control of European Commission — Responsibility of individual Commissioners.
Presidential Elements in Government Introduction
Authors: Reestman Jan Herman
Published: March 2006

The editorial board of the European Constitutional Law Review has solicited a number of contributions on presidential elements in government systems in Europe. At the origin of the project are some recent sweeping interventions of heads of state in the political arena. These are notably the (suspensive) veto of the domestic Act implementing the European Arrest Warrant Decision by Czech president Vaclav Klaus and the dissolution, against the will of both the government and the parliamentary majority, of the Assembleia da República by Portuguese president Jorge Sampaio in 2004. They excited our curiosity about the latent ingenuities of systems that we think to understand but of which we know so little.
Presidential Elements in Government Experimenting with Constitutional Change: Direct Election of the Prime Minister in Israel
Authors: Kretzmer David
Published: March 2006

A constitutional experiment in which a parliamentary system of government under proportional representation was combined with the direct election of a prime minister — the system prior to 1992 — the political context of the 1992 reform — the unintended consequences of the reform in practice — the return to a pure parliamentary form of government, combined with a constructive vote of no-confidence and a prime-ministerial power to dissolve parliament.
Contours of a European Social Union in the Case-Law of the European Court of Justice
Authors: Lenaerts Koen , Heremans Tinne
Published: March 2006

Tensions between national welfare systems and the social rights of the citizens of the Union — Fundamental principle of free movement and the degree of financial solidarity with nationals from other Member States — Introduction of internal market principles in health care — The balancing role of the Court of Justice of the European Communities.
Effect of the implementation of an enterprise-wide Electronic Health Record on productivity in the Veterans Health Administration
Authors: Evans Dwight C. , Nichol W. Paul , Perlin Jonathan B.
Published: March 2006

Since 1995, the Veterans Health Administration (VHA) has had an ongoing process of systems improvement that has led to dramatic improvement in the quality of care delivered. A major component of the redesign of the VHA has been the creation of a fully developed enterprise-wide Electronic Health Record (EHR). VHA’s Health Information Technology was developed in a collaborative fashion between local clinical champions and central software engineers. Successful national EHR implementation was achieved by 1999, since when the VHA has been able to increase its productivity by nearly 6 per cent per year.
Anatomie et physiopathologie du réseau veineux
Authors: Depairon
Published: March 2006

Le diagnostic de la maladie veineuse a longtemps souffert d'un manque de précision. Il en résulte des études sur la prise en charge de la pathologie veineuse difficilement comparables. Il est donc nécessaire de parler un même langage et d'adopter une classification unique dans le monde entier. Introduite en 1995, la classification CEAP fournit une bonne évaluation de la maladie veineuse en se basant sur les manifestations cliniques (C), les facteurs étiologiques (E), la distribution anatomique (A) et les mécanismes physiopathologiques (P) sous-jacents. Elle permet de mieux appréhender la pathologie veineuse, de réaliser des études épidémiologiques de qualité et d'évaluer de façon précise les différentes thérapeutiques.
La thrombose veineuse profonde: épidémiologie, facteurs de risque et évolution naturelle
Authors: Coiteux  , Mazzolai
Published: March 2006

La thrombose veineuse profonde (TVP) et l'embolie pulmonaire (EP) sont des causes majeures de morbidité et de mortalité. L'incidence de la TVP ne s'est pas modifiée dans les dernières décennies; dans la population générale, le nombre d'événements est estimé à 1/1000 personnes-année atteignant, chez les plus de 85 ans, 1 événement sur 100 personnes-année. La TVP est une maladie multifactorielle associée à de nombreux facteurs de risque, la majorité d'entre eux étant frequent. En se basant sur la présence ou l'absence de facteurs de risque ou de causes potentielles, la TVP peut être classifiée en secondaire ou idiopathique. Il est à présent accepté que l'interaction de plusieurs facteurs de risque dans le temps détermine le risque de thrombose.
Der Zuschnitt von Werbung auf die Zielgruppe älterer Menschen
Authors: Bieri Rahel , Florack Arnd , Scarabis Martin
Published: March 2006

Zusammenfassung. Das ökonomische Gewicht der älteren Bevölkerung wird zunehmend auch von Marketingexperten erkannt. Dennoch werden die grundlegenden Charakteristika dieser Konsumentengruppe bisher selten bei der Gestaltung von Werbung beachtet. In diesem Artikel geben wir eine Übersicht über die wichtigsten Forschungsergebnisse zur Rezeption von Werbung durch ältere Konsument/inn/en. Wir zeigen auf, dass Ältere im Vergleich zu Jüngeren bedeutende Unterschiede bei der Wahrnehmung und Verarbeitung von Werbung und insbesondere bei der späteren Erinnerung von Werbebotschaften aufweisen. Diese Unterschiede haben grundlegende Implikationen für die Gestaltung von Werbemaßnahmen, insbesondere im Hinblick auf eine adäquate, faire und effektive Ansprache älterer Konsument/inn/en.
Der Dritte-Person-Effekt, Thema der Werbung und Distanz der “dritten Person“
Authors: Moser Klaus , Leitl Julia
Published: March 2006

Zusammenfassung. Der Dritte-Person-Effekt (DPE) bezeichnet die Tendenz, andere (,dritte‘) Personen als beeinflussbarer durch Medien einzuschätzen als sich selbst. Der vorliegende Beitrag behandelt den Einfluss des Themas der Kommunikation, hier Werbebotschaften (Profit- vs. Nonprofit-Werbung) und der sozialen Distanz zwischen Selbst und anderen auf die Stärke des DPE. Nach dem Selbstwerterhöhungsansatz ist anzunehmen, dass der Effekt bei Profit-Werbung und bei zunehmender sozialer Distanz stärker auftritt. Die Ergebnisse unserer Untersuchung zur wahrgenommenen Wirkung unterschiedlicher Werbungen bestätigen diese Annahmen. Grenzen für das Auftreten des DPE werden aber ebenfalls sichtbar: Bei Nonprofit-Werbung zeigte sich (unabhängig von der sozialen Distanz) kein DPE.
What Makes Preschoolers Listen to Narrative Audio Tapes?
Authors: Vorderer Peter , Böcking Saskia , Klimmt Christoph , Ritterfeld Ute
Published: March 2006

Abstract. Most communication studies on children and media have focused solely on television. Other popular media products such as narrative audio tapes have been neglected. The present article addresses factors that influence preschoolers’ selective exposure to these tapes. In line with past research, the emotional attractiveness of a story’s protagonist and some formal design elements of the product are regarded as determinants of children’s frequency and persistence of using a given tape. An experimental diary study with 79 preschoolers revealed that both factors do in fact influence children’s usage of the tape. The resulting implications for fundamental and applied research on children and media are discussed.
Multiplet structure of acceleration processes in the distant magnetotail
Authors: Zelenyi L. M. , Grigorenko E. E. , Sauvaud J.‐A. , Maggiolo R.
Published: March 2006

We have studied ion distributions measured in the Plasma Sheet Boundary Layer (PSBL) of the Earth's magnetotail by the Cluster spacecraft at X ∼ −15Re. Field‐aligned ion beams (beamlets) accelerated in the magnetotail to energies of ∼30keV are typically observed within the interface region between the Plasma Sheet (PS) and the magnetotail lobes. PSBL beamlets are produced by non‐adiabatic ion acceleration in the vicinity of X‐line which is located, during quiet periods, in the distant parts of the tail. Earlier kinetic models attributed the filamentary and/or bursty nature of these processes to Current Sheet (CS) resonances and predicted the scaling law for the velocity of subsequent structures as VN ∼ N2/3. Cluster‐2 provides experimental evidence from the PSBL from of the existence of such resonant structures in ion velocity space and provides the first statistically proven identification of such a scaling law for quiet and moderately disturbed periods.
Latitude distribution of vertically precipitating energetic neutral atoms observed at low altitudes
Authors: Sørbø M. , Søraas F. , Aarsnes K. , Oksavik K. , Evans D. S.
Published: March 2006

Earlier modeling work of the latitude distribution of earthward traveling energetic neutral atoms (ENA) originating in the ring current have suggested that an isotropic ring current with an empty loss cone will deposit most ENA away from the magnetic equator, while a ring current with an equatorial pitch angle distribution peaked at 90° will deposit most ENA at the magnetic equator. We present the first direct low altitude measurements of energetic particles at low and equatorial latitudes supporting this model. The evolution from an isotropic ring current to a more anisotropic one is manifested in the latitude distribution of the low altitude energetic particles during a geomagnetic storm. In the growth and main phase of the storm the latitude distribution of the energetic particles is wide and often show secondary peaks away from the equator, while in the recovery phase the latitude distribution narrows and peaks at the magnetic equator.
Electrical evidence of continental accretion: Steeply‐dipping crustal‐scale conductivity contrast
Authors: Selway Kate , Heinson Graham , Hand Martin
Published: March 2006

Many geophysical images of ancient orogenic belts utilise seismic reflection data but increasingly magnetotelluric (MT) data have been shown to provide insights into orogenic architecture not evident in seismic surveys, particularly through their ability to image steep structures. A 140km long MT survey carried out in Palaeoproterozoic crust in central Australia has imaged a crustal‐scale conductivity contrast across a steeply‐dipping boundary. The surface location of this contrast coincides with the Redbank Thrust Zone, previously shown from seismic reflection and gravity data to be a moderately‐dipping, thick‐skinned fault that produces one of the largest continental gravity gradients known on Earth. The steeply‐dipping conductivity interface is interpreted to be a strike‐slip boundary separating the North Australian Craton from a younger accreted terrane. This result is therefore a first‐order geophysical image of a Proterozoic accretion system in Australia. The steep boundary is not evident in the seismic data and highlights the utility of MT in defining fundamental crustal boundaries.
Maximum entropy production and the strength of boundary layer exchange in an atmospheric general circulation model
Authors: Kleidon Axel , Fraedrich Klaus , Kirk Edilbert , Lunkeit Frank
Published: March 2006

Boundary layer turbulence plays a central role in determining the strength of the overall atmospheric circulation by affecting the intensity of exchange of heat, mass, and momentum at the Earth's surface. It is often parameterized using the bulk formula, in which the von‐Karman parameter plays a critical role. Here we conducted a range of sensitivity simulations with an atmospheric general circulation model in which we modified the strength of boundary layer turbulence by varying the von‐Karman parameter. These simulations show that the maximum of entropy production associated with boundary layer dissipation is consistent with the observed value of the von‐Karman parameter of 0.4 and maximizes the planetary rate of entropy production with the global radiative temperature being close to its minimum value. Additional sensitivity simulations were conducted with an increased concentration of atmospheric carbon dioxide, which affects the relative radiative forcing of tropical vs. polar regions. We find that the global climate sensitivity is more‐or‐less independent of the assumed strength of boundary layer turbulence in our idealized setup. The difference in climate sensitivities of tropical and polar regions is at a minimum at a climatic state of MEP.
Aerosol indirect effect over the Indian Ocean
Authors: Chylek Petr , Dubey M. K. , Lohmann U. , Ramanathan V. , Kaufman Y. J. , Lesins G. , Hudson J. , Altmann G. , Olsen S.
Published: March 2006

We analyze the MODIS (Moderate Resolution Imaging Spectroradiometer) satellite data over the seas adjacent to the Indian sub‐continent to investigate the effect of aerosols on the size distribution of cloud droplets and ice crystals (indirect aerosol effect). During the winter months of increased anthropogenic pollution we observe smaller sizes of cloud droplets in water clouds in agreement with the expected aerosol indirect effect. However, contrary to our expectations, we find that during episodes of increased pollution the effective radius of ice crystals is shifted toward the larger rather than smaller sizes. We propose a combination of natural seasonal variability of meteorological conditions and an “inverse aerosol indirect effect” caused by heterogeneous ice nucleation as a possible explanation of observed ice crystal growth. The ECHAM4 (European Center for Medium‐Range Weather Forecast Hamburg version 4th generation GCM) results with heterogeneous ice nucleation reproduce the observed increase in ice crystal size during the enhanced pollution episodes.
Static stress change from the 8 October, 2005 M = 7.6 Kashmir earthquake
Authors: Parsons Tom , Yeats Robert S. , Yagi Yuji , Hussain Ahmad
Published: March 2006

We calculated static stress changes from the devastating M = 7.6 earthquake that shook Kashmir on 8 October, 2005. We mapped Coulomb stress change on target fault planes oriented by assuming a regional compressional stress regime with greatest principal stress directed orthogonally to the mainshock strike. We tested calculation sensitivity by varying assumed stress orientations, target‐fault friction, and depth. Our results showed no impact on the active Salt Range thrust southwest of the rupture. Active faults north of the Main Boundary thrust near Peshawar fall in a calculated stress‐decreased zone, as does the Raikot fault zone to the northeast. We calculated increased stress near the rupture where most aftershocks occurred. The greatest increase to seismic hazard is in the Indus‐Kohistan seismic zone near the Indus River northwest of the rupture termination, and southeast of the rupture termination near the Kashmir basin.
Quasi‐adiabaticity in bifurcated current sheets
Authors: Delcourt D. C. , Malova H. V. , Zelenyi L. M.
Published: March 2006

We examine the non‐linear dynamics of charged particles in “bifurcated” (double‐humped) current sheets. We show that, when the adiabaticity parameter κ is of the order unity, particles experience a negligible change of magnetic moment. Such a behavior contrasts with the prominent magnetic moment scattering that is achieved in single‐humped current sheets at such κ values. It resembles the quasi‐adiabatic (Speiser‐type) behaviors that is obtained at κ ≪ 1 as a result of resonance between the fast oscillation about the midplane and the slow gyromotion near this plane. We demonstrate that beams of κ ≈ 1 particles may form downstream of bifurcated current sheets, which propagate along the magnetic field lines up to high latitudes. Quasi‐adiabaticity and associated beam formation thus occur at significantly larger κ values in double‐humped current sheets than in single‐humped ones, or equivalently for lower particle energy and/or weaker field reversal.
Winter atmospheric circulation and river discharge in northwest Europe
Authors: Bouwer Laurens M. , Vermaat Jan E. , Aerts Jeroen C. J. H.
Published: March 2006

More frequent western atmospheric circulation over Europe results in increased precipitation in winter, and could result in increasing river discharges. We made a quantitative assessment of the impact of variation in atmospheric circulation, defined by the frequency of western circulation in the Großwetterlagen classification system and the North Atlantic Oscillation (NAO) index, on variation in basin‐average precipitation and winter discharges (December–February) of eleven large river basins that drain northwest Europe. Annual winter discharges amounts are highly correlated among these rivers (up to r2 = 0.82, decreasing with increasing inter‐basin distance), which may point to a common atmospheric forcing. The number of days of western atmospheric circulation in winter as indicated by the Großwetterlagen classification system is more closely related (r2 = 0.06 to r2 = 0.28, p < 0.05 or better) to winter river discharges than the NAO index. We therefore conclude that the frequency of western atmospheric circulation over Europe is a better indicator of climate variability and climate change impacts on river discharges in northwest Europe.
Changes in the timing of winter–spring streamflows in eastern North America, 1913–2002
Authors: Hodgkins Glenn A. , Dudley Robert W.
Published: March 2006

Changes in the timing and magnitude of winter‐spring streamflows were analyzed for gaging stations in eastern North America north of 41° north latitude during various periods through 2002. Approximately 32 percent of stations north of 44° have significantly earlier flows over the 50, 60, 70, and 90 year periods; 64 percent have significantly earlier flows over the 80 year period; there are no stations significantly later flows for any time period examined. Flows for the average of all stations north of 44° became earlier by 6.1, 4.4, 4.8, 8.6, and 6.5 days for the 50 through 90 year periods, respectively. Changes over time in monthly mean runoff support the flow timing results—January, February, and particularly March runoff show much higher percentages of stations with increases than with decreases over all time periods and May runoff shows relatively high percentages of stations with decreases.
Coseismic surface deformation from air photos: The Kickapoo step over in the 1992 Landers rupture
Authors: Michel Rémi , Avouac Jean‐Philippe
Published: March 2006

Coseismic deformation of the ground can be measured from aerial views taken before and after an earthquake. We chose the area of the Kickapoo‐Landers step over along the 1992 Landers earthquake zone, using air photos (scale 1:40,000) scanned at 0.4 m resolution. Two photos acquired after the earthquake are used to assess the accuracy and to evaluate various sources of noise. Optical distortions, film deformation, scanning errors, or errors in viewing parameters can yield metric bias at wavelength larger than 1 km. Offset field at shorter wavelength is more reliable and mainly affected by temporal decorrelation of the images induced by changes in radiometry with time. Temporal decorrelation and resulting uncertainty on offsets are estimated locally from the correlation degree between the images. Relative surface displacements are measured independently every about 15 m and with uncertainty typically below 10 cm (RMS). The offset field reveals most of the surface ruptures mapped in the field. The fault slip is accurate to about 7 cm (RMS) and measured independently every 200 m from stacked profiles. Slip distribution compares well with field measurements at the kilometric scale but reveals local discrepancies suggesting that deformation is generally, although not systematically, localized on the major fault zone located in the field. This type of data can provide useful insight into the fault zone's mechanical properties. Our measurements indicate that elastic coseismic strain near the fault zone can be as large as 0.5 × 10−3, while anelastic yielding was attained for strain in excess of about 1–2 × 10−3.
Tectonic stressing in California modeled from GPS observations
Authors: Parsons Tom
Published: March 2006

What happens in the crust as a result of geodetically observed secular motions? In this paper we find out by distorting a finite element model of California using GPS‐derived displacements. A complex model was constructed using spatially varying crustal thickness, geothermal gradient, topography, and creeping faults. GPS velocity observations were interpolated and extrapolated across the model and boundary condition areas, and the model was loaded according to 5‐year displacements. Results map highest differential stressing rates in a 200‐km‐wide band along the Pacific‐North American plate boundary, coinciding with regions of greatest seismic energy release. Away from the plate boundary, GPS‐derived crustal strain reduces modeled differential stress in some places, suggesting that some crustal motions are related to topographic collapse. Calculated stressing rates can be resolved onto fault planes: useful for addressing fault interactions and necessary for calculating earthquake advances or delays. As an example, I examine seismic quiescence on the Garlock fault despite a calculated minimum 0.1–0.4 MPa static stress increase from the 1857 M∼7.8 Fort Tejon earthquake. Results from finite element modeling show very low to negative secular Coulomb stress growth on the Garlock fault, suggesting that the stress state may have been too low for large earthquake triggering. Thus the Garlock fault may only be stressed by San Andreas fault slip, a loading pattern that could explain its erratic rupture history.
Crustal structure of China and surrounding regions from P wave traveltime tomography
Authors: Sun Youshun , Toksöz M. Nafi
Published: March 2006

A three‐dimensional (3‐D) P wave velocity model is developed for the crust and uppermost mantle of China and the surrounding area by applying the tomography method of Zhao et al. using 500,000 high‐quality P wave first arrivals extracted from the Annual Bulletin of Chinese Earthquakes (ABCE). This tomographic method can accommodate velocity discontinuities such as the Moho in addition to smooth velocity variations. The spatial resolution is 1° × 1° in the horizontal direction and 10 km in depth. The velocity images of the upper crust correspond well with the surface geologic features such as basins and the Tibetan Plateau. High‐velocity anomalies are found in the lower crust beneath the Precambrian regions (Tarim Basin, Ordos Basin, Sichuan Basin, and western half of Songliao Basin). The highest‐velocity anomaly is beneath the Sichuan Basin. High‐ and low‐velocity anomalies imaged beneath the Bohai Gulf are associated with the presence of a major Cenozoic rift system. In the lower crust beneath the South China Block, P wave velocities are lower in the north than in the south. The Indochina Block shows low velocities both in the crust and in the uppermost mantle due to volcanism. The Pn velocities in the Tibet area are higher than those in other areas largely due to thicker crust. Tomographic model significantly reduces the traveltime residuals. Tests conducted by relocating large explosions and earthquakes validate the 3‐D velocity model.
Observing seasonal steric sea level variations with GRACE and satellite altimetry
Authors: Chambers Don P.
Published: March 2006

Sea level rises and falls as the temperature and salinity of the water column varies, which is known as steric sea level. Sea level also changes as water mass is redistributed within the ocean or is added or removed. Satellite radar altimeters measure the combination of both effects, while the Gravity Recovery and Climate Experiment (GRACE) was designed to measure time variable gravity caused by movement of water mass. Theoretically, altimetry and GRACE data can be combined in order to compute the steric sea level variations. We test this by combining current GRACE and Jason 1 altimeter data and comparing against steric sea level observations. We will describe how to properly combine the altimetry and GRACE data, commenting on important corrections that need to be applied to each data type. Using empirical orthogonal function (EOF) analysis, we examine the leading modes of seasonal variability and find that using GRACE improves the ability to recover the dominant mode of steric sea level variability over using altimetry alone. The RMS error of the GRACE ocean mass variations is estimated to be about 2 cm of sea level at a 1000 km smoothing radius. Although this is larger than initially predicted from the GRACE mission, it is still significantly smaller than the recovered signal in several regions of the ocean.
Whitecap coverage from satellite measurements: A first step toward modeling the variability of oceanic whitecaps
Authors: Anguelova Magdalena D. , Webster Ferris
Published: March 2006

We present estimates of whitecap coverage on a global scale from satellite‐measured brightness temperature of the ocean surface. This is a first step in a larger framework aiming at more realistic modeling of the high variability of whitecap coverage as a function of wind speed and a suite of additional environmental and meteorological factors. The involvement of oceanic whitecaps in various physical and chemical processes important for climate studies such as production of sea‐salt aerosols, enhancement of air‐sea gas exchange, and influence on retrievals of ocean surface wind and ocean color motivates this effort. A critical review of the physical variables causing the high variability of whitecap coverage and existing approaches modeling this variability establishes the need for a database of whitecap coverage and concomitant measurements of additional factors. The necessity to build such an extensive database justifies the quest for a method estimating whitecap coverage from satellite data. We describe the physical concept, a possible implementation, error analysis, results, and evaluation of a method for estimating whitecap coverage from routine satellite measurements. The advantages of the concept and the drawbacks and necessary improvements of the implementation are discussed.