bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of damage on pore size distribution and permeability of rocks
Authors: Arson Chloé , Pereira Jean‐Michel
Published: January 2012

The model proposed in this article relates permeability to porosity measurements that can easily be performed in the laboratory. The pore size distribution (PSD) curve is updated with strains and damage. The updated volumetric fractions of natural pores and cracks are introduced in the expression of permeability. Contrary to classical permeability models based on PSD integrations, the model proposed in this article accounts for possible changes in the porosity modes: one mode for undamaged samples and two modes for cracked samples. The proposed approach also accounts for varying states of damage, as opposed to classical fracture network models, in which the cracks pattern is fixed. The only material parameters that are required to describe the microstructure are the lower and upper bounds of the pores size for both natural pores and cracks. All the other PSD parameters involved in the model are related to macroscopic parameters that can easily be determined in the laboratory, such as the initial void ratio. The framework proposed in this article can be used in any damage constitutive model to determine the permeability of a brittle porous medium. Drained triaxial compression tests have been simulated. Before cracks initiation, permeability decreases while the larger natural pores are getting squeezed. After the occurrence of damage, permeability grows due to the increase of cracks density. The model performs well to represent the influence of the confining pressure on damage evolution and permeability variations. Copyright © 2012 John Wiley & Sons, Ltd.
A mobility model for studying wireless communication and the complexity of problems in the model
Authors: Greenlaw Raymond , Kantabutra Sanpawat , Longani Pattama
Published: January 2012

Wireless communication has become omnipresent in the world and enables users to have an unprecedented ability to communicate any time and any place. In this article, we propose a mobility model for studying wireless communication. The model incorporates elements such as users, access points, and obstacles so that it faithfully mimics the real environment. Interesting problems that have practical applications are posed and solved. More specifically, we study the complexity of three problems in a grid. The source reachability problem (SRP) models a situation in which we want to determine whether two access points can communicate at a certain time in a mobile environment. When users are involved in this situation, we call this problem the user communication problem (UCP). We show that SRP can be solved in O(max{d,t}m2) time, where d is the number of obstacles, t is the time bound in the statement of the problem, and m is the number of access points; we show that UCP can be solved in O(max{d,t}m4) time. The third problem called the user communication, limited source access problem (UCLSAP) studies a situation where we want to determine whether two users can communicate uninterruptedly during the duration of the model while considering battery‐time limits of the access points. In contrast to the first two problems, we demonstrate that UCLSAP is intractable, unless P = NP. In conclusion, we briefly discuss the extension of our model to three dimensions and provide a list of open problems. © 2012 Wiley Periodicals, Inc. NETWORKS, 2012
Deterministic rendezvous in networks: A comprehensive survey
Authors: Pelc Andrzej
Published: January 2012

Two or more mobile entities, called agents or robots, starting at distinct initial positions, have to meet. This task is known in the literature as rendezvous. Among many alternative assumptions that have been used to study the rendezvous problem, two most significantly influence the methodology appropriate for its solution. The first of these assumptions concerns the environment in which the mobile entities navigate: it can be either a terrain in the plane, or a network modeled as an undirected graph. The second assumption concerns the way in which the entities move: it can be either deterministic or randomized. In this article, we survey results on deterministic rendezvous in networks. © 2012 Wiley Periodicals, Inc. NETWORKS, 2012
Velocity and range of fragments from accidental explosions
Authors: Dostal L. , Janovsky B. , Ferjencik M.
Published: January 2012

A method for determining the initial velocity and range of flying fragments is proposed. Quantity‐Distance (Q‐D) principles are discussed and some arguments are presented for why even the observance of Q‐D principles cannot prevent sympathetic explosions due to flying fragments. Example calculations are included and the results are compared to the results of an actual explosion. The results show that this method should be suitable for evaluating fragment velocity and range. Limitations of the method and proposals for possible future improvements are discussed in the conclusions. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012
Isolation and expression of genes for acetolactate synthase and acetyl‐CoA carboxylase in Echinochloa phyllopogon, a polyploid weed species
Authors: Iwakami Satoshi , Uchino Akira , Watanabe Hiroaki , Yamasue Yuji , Inamura Tatsuya
Published: January 2012

BACKGROUND: Target‐site resistance is the major cause of herbicide resistance to acetolactate synthase (ALS)‐ and acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides in arable weeds, whereas non‐target‐site resistance is rarely reported. In the Echinochloa phyllopogon biotypes resistant to these herbicides, target‐site resistance has not been reported, and non‐target‐site resistance is assumed to be the basis for resistance. To explore why target‐site resistance had not occurred, the target‐site genes for these herbicides were isolated from E. phyllopogon, and their expression levels in a resistant biotype were determined.

RESULTS: Two complete ALS genes and the carboxyltransferase domain of four ACCase genes were isolated. The expression levels of ALS and ACCase genes were higher in organs containing metabolically active meristems, except for ACC4, which was not expressed in any organ. The differential expression among examined organs was more prominent for ALS2 and ACC2 and less evident for ALS1, ACC1 and ACC3.

CONCLUSION: E. phyllopogon has multiple copies of the ALS and ACCase genes, and different expression patterns were observed among the copies. The existence of three active ACCase genes and the difference in their relative expression levels could influence the occurrence of target‐site resistance to ACCase inhibitors in E. phyllopogon. Copyright © 2012 Society of Chemical Industry
Affect of film thickness on the blue photoluminescence from ZnO
Authors: Moore J. C. , Covington L. R. , Stansell R.
Published: January 2012

We have investigated the photoluminescence (PL) properties of ZnO grown on sapphire substrates via the thermal oxidation of Zn‐metal films at various temperatures and having various thicknesses. PL spectra indicate four emission bands: excitonic ultraviolet (UV), blue, and deep‐level green and yellow emission. The ratio of deep‐level green emission to UV excitonic emission was observed to decrease with decreasing annealing temperature from 1200 to 300 °C, which is attributed to the generation of fewer oxygen vacancies (${\rm V}_{{\rm O}}^{ + } $) and interstitial oxygen ions (${\rm O}_{{\rm i}}^{- } $) in the bulk. As film thickness decreased from approximately 600 to 200 nm, we observed the emergence of blue emission and a significant red shift (0.15 eV) in the bandgap. The emergence of blue emission and the corresponding decrease in emission associated with bulk defects when depletion width grows relative to the bulk suggests that the origin of the blue emission is related to the charged zinc interstitials (${\rm V}_{{\rm Zn}}^{- } $) found within the deletion region near the interface.
Atomic‐ and molecular‐scale devices and systems for single‐molecule electronics
Authors: Prauzner‐Bechcicki Jakub S. , Godlewski Szymon , Szymonski Marek
Published: January 2012

Present‐day electronic technology, based to a large extent on silicon fabricated devices, is surely approaching size limitations arising from quantum effects. The effort to achieve rapid development of electronic devices requires implementation of entirely new ideas that will allow existing technological constraints to be overcome. Among a wide range of concepts, utilization of single organic molecules, acting as active blocks performing logic operations, appears as one of the most appealing and is based on the state‐of‐the‐art use of modern nanotechnology. In this short review, we offer a selection of recent experiments addressing milestones of single‐molecule computing devices technology. Along with discussion of the latest achievements in atomic‐ and molecular‐scale technologies, we discuss their future perspectives, challenges, and still unsolved issues standing in the way of practical implementation of single‐molecule devices.

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Concept of a single‐molecule electronic device. The molecule is equipped with various functional groups responsible for logic operations and bonding to an underlying surface and metallic nanoelectrodes. The monomolecular nanodevice is deposited on a thin buffer layer assuring the decoupling from a (semi‐)conducting substrate.
Enhanced performance in inverted organic light emitting diode assisted by an interlayer of crystalline and n‐doped 1,4,5,8‐naphthalene‐tetracarboxylic‐dianhydride
Authors: Qin Dashan , Chen Lei , Chen Yuhuan , Liu Jinsuo , Li Guifang , Quan Wei , Zhang Jidong , Yan Donghang
Published: January 2012

Inverted bottom‐emission organic light emitting diodes (IBOLEDs) employing the electron injection structure of indium tin oxide (ITO)/1,4,5,8‐naphthalene‐tetracarboxylic‐dianhydride (NTCDA)/Li2CO3 doped bathocuproine (BCP) (1:4 Li2CO3:BCP) were fabricated, where NTCDA and BCP stand for NTCDA and BCP, respectively. The NTCDA on ITO was characterized crystalline and n‐doped as a result of the interaction between ITO and NTCDA. Compared to the IBOLED using the electron injection structure of ITO/10 nm 1:4 Li2CO3:BCP, the one utilizing the electron injection structure of ITO/3 nm NTCDA/7 nm 1:4 Li2CO3:BCP showed the remarkable increases in both current density and efficiency, mainly due to the higher electron conductivity of n‐doped NTCDA than that of n‐doped BCP. The dependence of the current conduction in IBOLED on the thickness of NTCDA was investigated. We provide a simple method to significantly enhance the performance of IBOLEDs.
Well‐ordered arrays of ferroelectric single‐crystalline BaTiO3 nanostructures
Authors: Chen Di , Zhang Haitao , Chen Rike , Deng Xiangyun , Li Jianbao , Zhang Guoqing , Wang Liming
Published: January 2012

Highly ordered arrays of BaTiO3 nanostructures were synthesized by the hydrothermal method using TiO2 nanotube arrays as templates. The synthesis yields apparent preferred orientation nanostructures with a perovskite structure. The pristine nanostructures are high purity and contain some degree of hydroxyl group or absorbed oxygen. Ferroelectric domains are present at the nanostructures, and typical hysteresis loops with remanent polarization and coercive field are 8.93 µC cm2 and 53 kV/cm, respectively.
Large‐scale interventions in science education for diverse student groups in varied educational settings
Authors: Lee Okhee , Krajcik Joseph
Published: January 2012

Current classroom practices in the U.S. and internationally have largely been shaped by changing student demographics and accountability policies. This special issue includes manuscripts that develop conceptual frameworks or report on empirical studies addressing large‐scale interventions of educational innovations for diverse student groups in varied educational settings. Understanding issues related to large‐scale interventions will be particularly important for the U.S. as the science education system embraces new science standards [National Research Council, [2011] A framework for K‐12 science education: Practices, crosscutting concepts, and core ideas. Washington, DC: National Research Council.]. In our introduction to the special issue, we discuss critical issues in scaling up educational innovations through which large‐scale interventions evolve. First, we describe the process of scaling up an educational innovation. Then, we address challenges in scaling up an innovation. Next, we discuss implications that these challenges present to implementation of an innovation and evaluation of its efficacy and effectiveness. Finally, we briefly introduce the articles that appear in this special issue. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 271–280, 2012
Overactive bladder in men: initial assessment
Authors: Birch Andrew , Dowson Christopher , Seth Jai , Khan Mohammad Shamim , Dasgupta Prokar , Sahai Arun
Published: January 2012

In the first of a two‐part series, the authors provide an overview of the prevalence and impact of overactive bladder, and give advice on frontline investigation and how and when to refer. Part 2 will cover the goals and strategies of therapy. Copyright © 2012 John Wiley & Sons
Identification and characterization of a novel cold-adapted esterase from a metagenomic library of mountain soil
Authors: Ko Kyong-Cheol , Rim Soon-Ok , Han Yunjon , Shin Bong Seok , Kim Geun-Joong , Choi Jong Hyun , Song Jae Jun
Published: January 2012

A novel lipolytic enzyme was isolated from a metagenomic library after demonstration of lipolytic activity on an LB agar plate containing 1% (w/v) tributyrin. A novel esterase gene (estIM1), encoding a lipolytic enzyme (EstIM1), was cloned using a shotgun method from a pFosEstIM1 clone of the metagenomic library, and the enzyme was characterized. The estIM1 gene had an open reading frame (ORF) of 936 base pairs and encoded a protein of 311 amino acids with a molecular mass 34 kDa and a pI value of 4.32. The deduced amino acid sequence was 62% identical to that of an esterase from an uncultured bacterium (ABQ11271). The amino acid sequence indicated that EstIM1 was a member of the family IV of lipolytic enzymes, all of which contain a GDSAG motif shared with similar enzymes of lactic acid microorganisms. EstIM1 was active over a temperature range of 1–50°C, at alkaline pH. The activation energy for hydrolysis of p-nitrophenyl propionate was 1.04 kcal/mol, within a temperature range of 1–40°C. The activity of EstIM1 was about 60% of maximal even at 1°C, suggesting that EstIM1 is efficiently cold-adapted. Further characterization of this cold-adapted enzyme indicated that the esterase may be very valuable in industrial applications.
Effect of competition on habitat utilization in two temperate climate gecko species
Authors: Lisičić Duje , Drakulić Sanja , Herrel Anthony , Đikić Domagoj , Benković Vesna , Tadić Zoran
Published: January 2012

Competition over spatial niche utilisation is one of most common competitive interactions between species in sympatry. Moreover, competitive interactions may involve age classes, and can fluctuate temporally. Consequently, evasive strategies that enable co‐existence are likely to be important in the evolution of species assemblages. Here we investigate a system of two co‐existing species of temperate geckos with similar ecologies (the house gecko, Hemidactylus turcicus and the wall gecko, Tarentola mauritanica), providing an opportunity to study the effect of species interactions. Juveniles and adults of both species were investigated throughout their daily and annual cycle to explore the effect of inter‐ and intra‐specific interactions on microhabitat use. The two species showed differences in habitat use for both age classes in sympatry. In sympatry, T. mauritanica uses more open habitats and is more active. In contrast, H. turcicus is found in more closed habitats, closer to the ground and to vegetation cover. In allopatry, H. turcicus was observed in more open habitats, closer to the ground, and to vegetation cover, when compared to the population in sympatry with T. mauritanica. These differences in habitat usage were significant for both age classes. Moreover, there were differences, both in sympatry and in allopatry, between age classes that were dependent on season. In conclusion, the presence of a competitor induces a spatial shift in individuals of both age classes of H. turcicus. Observed plasticity in habitat utilisation in both age classes of H. turcicus is used to argue for the invasive potential of this species.
Enhancement of Intestinal Permeability Utilizing Solid Lipid Nanoparticles Increases γ‐Tocotrienol Oral Bioavailability
Authors: Abuasal Bilal S. , Lucas Courtney , Peyton Breanne , Alayoubi Alaadin , Nazzal Sami , Sylvester Paul W. , Kaddoumi Amal
Published: January 2012

γ‐Tocotrienol (γ‐T3), a member of the vitamin E family, has been reported to possess an anticancer activity. γ‐T3 is a lipophilic compound with low oral bioavailability. Previous studies showed that γ‐T3 has low intestinal permeability. Thus, we have hypothesized that enhancing γ‐T3 intestinal permeability will increase its oral bioavailability. Solid lipid nanoparticles (SLN) were tested as a model formulation to enhance γ‐T3 permeability and bioavailability. γ‐T3 intestinal permeability was compared using in situ rat intestinal perfusion, followed by in vivo relative oral bioavailability studies. In addition, in vitro cellular uptake of γ‐T3 from SLN was compared to mixed micelles (MM) in a time and concentration‐dependent studies. To elucidate the uptake mechanism(s) of γ‐T3 from SLN and MM the contribution of NPC1L1 carrier‐mediated uptake, endocytosis and passive permeability were investigated. In situ studies demonstrated SLN has tenfold higher permeability than MM. Subsequent in vivo studies showed γ‐T3 relative oral bioavailability from SLN is threefold higher. Consistent with in situ results, in vitro concentration dependent studies revealed γ‐T3 uptake from SLN was twofold higher than MM. In vitro mechanistic characterization showed that while endocytosis contributes to γ‐T3 uptake from both formulations, the reduced contribution of NPC1L1 to the transport of γ‐T3, and passive diffusion enhancement of γ‐T3 are primary explanations for its enhanced uptake from SLN. In conclusion, SLN successfully enhanced γ‐T3 oral bioavailability subsequent to enhanced passive permeability.
Is news media related to civic engagement? The effects of interest in and discussions about the news media on current and future civic engagement of adolescents
Authors: Erentaitė Rasa , Žukauskienė Rita , Beyers Wim , Pilkauskaitė‐Valickienė Rasa
Published: January 2012

This study explored whether discussions about the media, when positively linked to interest in the news media, were related to adolescents' current and future civic engagement. A sample of 2638 adolescents (ageM = 17,SD = 1.2), who participated in a school‐based study on positive socialization, completed self‐report measures on interest in the news media and discussions about the media with parents and friends. Current civic engagement was measured by involvement in volunteering and civic commitments. Future civic engagement was measured by intentions to participate in civic activities in the future. The results showed that more interpersonal discussions about the media and higher interest in the news media both predicted higher civic engagement. Positive links between discussions about the media and current civic engagement were partly mediated by interest in the news media. In addition, interest in the news media together with current civic engagement fully mediated a positive link between discussions about the media and future civic engagement. Moderating effects of gender were observed, with discussions about the media a better predictor of boys' interest in the news media, and current civic engagement a better predictor of girls' future civic engagement.
Entering into politics: Interdiscursivity, register, stance, and vernacular in northern Italy
Authors: Cavanaugh Jillian R.
Published: January 2012

This article focuses on how specific types of language use connect socially, geographically, and temporally distant speakers and span face-to-face and mediated language contexts. It examines one variety of political language (the Northern League register in Italy) in order to analyze how the interdiscursive potentials of register and stance-taking enable such connections. It also presents the metapragmatic effects of engaging in types of talk such as political language, which are less about individual expression or political participation, but are rather part of a complex of stance-taking and alignment of self within local and national political debates. Based on long-term ethnographic and linguistic research in Bergamo, Italy, this article introduces the concept of the interdiscursive trap, showing how the Northern League register functions in this capacity, forging indexical links to particular ideas and stances that some speakers find undesirable. (Political language, interdiscursivity, register, stance, Italy, Europe, Northern League, media)*
Across languages and cultures: Brokering problems of understanding in conversational repair
Authors: Bolden Galina B.
Published: January 2012

This article examines the interactional construction of language competence in bilingual immigrant communities. The focus is on how participants in social interaction resolve problems of understanding that are demonstrably rooted in their divergent linguistic and cultural expertise. Using the methodology of conversation analysis to examine mundane video-recorded conversations in Russian-American immigrant families, I describe a previously unanalyzed communicative practice for solving understanding problems: by one participant enacting the role of a language broker in a repair sequence. The article thus contributes to the existing research on the interactional construction of language competence, on the one hand, and on the organization of repair and its relationship to social epistemics, on the other. (Language brokering, repair, conversation analysis, social epistemics, multiparty conversation, Russian, immigrant families, intercultural communication)*
BEYOND HEGEL'S END OF ART: SCHADOW'S MIGNON AND THE RELIGIOUS PROJECT OF LATE ROMANTICISM
Authors: GREWE CORDULA
Published: January 2012

This article explores the cultural controversy about the relationship between painting and poetry sparked by Wilhelm von Schadow's 1828 rendering of Mignon, a famous literary heroine in Goethe's Wilhelm Meister's Apprenticeship. Following closely a position introduced by Lessing and endorsed by Goethe, and using it to advance his general thesis about the end of art, Hegel argued that Schadow's image transgressed the proper borders of its medium by attempting to translate the poetic into the visual. Schadow, by contrast, insisted on the crucial regenerative role of art in society and art's religious mission, thereby giving an emphatically Christian tenor to the Romantic injunction to strive after the infinite. Animated by these convictions, Schadow turned Goethe's heroine into an allegory of Romantic art, thus “Christianizing” Goethe's neoclassical sensibility. The controversy provoked by Schadow's Mignon provides an opportunity to explore late Romantic aesthetics and the cultural and political meaning of art within the context of the Prussian Restoration, as well as to reconsider the relationship between this putatively conservative sensibility and “modernism.”
Kognitionspsychologische Aspekte eines Kompetenzmodells zur Bild-Text-Integration
Authors: Ullrich Mark , Schnotz Wolfgang , Horz Holger , McElvany Nele , Schroeder Sascha , Baumert Jürgen
Published: January 2012

Zusammenfassung. Der Projekttitel BiTe steht für ein Forschungsvorhaben, das die schulische Kompetenzentwicklung im Bereich der integrierten Verarbeitung von Bild- und Textinformationen untersucht. Ausgangspunkt sind dabei kognitionspsychologische Überlegungen zu den mentalen Prozessen, die dem Wissenserwerb mit Texten und Bildern zugrunde liegen. So lässt sich anhand des Modells zum integrierten Text-Bild-Verstehen von Schnotz und Bannert (2003) ableiten, dass die gemeinsame Verarbeitung von verbalen und visuellen Informationen besondere Anforderungen an die Schülerinnen und Schüler stellt. Deren Bewältigung verlangt das Vorhandensein einer grundlegenden Kompetenz, die über das reine Leseverstehen hinausgeht, im schulischen Kontext aber bislang nicht unterrichtet wird. Aus diesem Grund ist es ein zentrales Ziel des BiTe-Projekts, die Kompetenz zur integrativen Verarbeitung von Texten und Bildern fassbar zu machen, indem ein theoretisches Strukturmodell entwickelt wurde ( Schnotz et al., 2010 ). Demzufolge beruht die integrative Verarbeitung von Texten und Bildern zu einem großen Teil auf Strukturabbildungsprozessen, die ineinander verschachtelt sind. Je nach Anzahl der beteiligten Elemente und deren Relationen lassen sich dabei drei hierarchische Kompetenzebenen unterscheiden, denen verschiedene Integrationsanforderungen zugeordnet werden können. Um die theoretischen Modellannahmen zu prüfen, wurde eine Reihe von Aufgaben entwickelt und in einer umfangreichen Studie pilotiert. Die Struktur der Kompetenz zur integrativen Verarbeitung von Texten und Bildern wurde dabei auf der Grundlage verschiedener Testmodelle evaluiert. Es zeigte sich jedoch, dass multidimensionale Modelle aufgrund hoher Korrelationen zwischen den einzelnen Skalen die Struktur nur unzureichend abbilden konnten.
Entwicklung und wechselseitige Effekte von metakognitiven und bereichsspezifischen Wissenskomponenten in der Sekundarstufe
Authors: Artelt Cordula , Neuenhaus Nora , Lingel Klaus , Schneider Wolfgang
Published: January 2012

Zusammenfassung. Gegenstand des Beitrags sind die bislang kaum untersuchten Entwicklungsverläufe und das Zusammenwirken von metakognitivem und von bereichsspezifischem Wissen bezogen auf die Leistungsbereiche Deutsch/Lesen und Englisch in den Klassenstufen 5 und 6 der Sekundarstufe. Die hier berichteten Analysen stammen aus einer Teilstichprobe (N = 853) einer im Rahmen des DFG-Schwerpunktprogrammes „Kompetenzmodelle” geförderten Längsschnittuntersuchung zur Entwicklung von Wissenskomponenten (EWIKO). Zur Erfassung des bereichsspezifischen Wissens (Schulleistungen) und des metakognitiven Wissens in den Leistungsbereichen Deutsch/Lesen und Englisch wurden eigene Verfahren konstruiert und pilotiert. Im Beitrag gehen wir zunächst der Frage nach, ob und in welchem Maße es zu Wissenszuwächsen im metakognitiven Wissen und in den Leistungen über einen Zeitraum von 16 Monaten (2 Messzeitpunkte) kommt und inwiefern diese Veränderungen dabei in Abhängigkeit von der besuchten Schulform variieren. Sowohl für die Leistungen als für das metakognitive Wissen zeigen Differenzscore-Modelle bedeutsame Zuwächse, die für den Leistungsbereich Englisch auch in Abhängigkeit von der Schulform variieren. Das zweite Ziel der längsschnittlichen Analysen besteht darin, den relativen Einfluss der bereichsspezifischen Ausgangsleistung und des metakognitiven Wissens auf die spätere Leistungen (Lesekompetenz im Leistungsbereich Deutsch/Lesen und Sprachverstehen im Bereich Englisch) zu untersuchen. Mittels Cross-Lagged-Panel-Analysen konnte u.a. die Annahme bestätigt werden, dass sowohl inter-individuelle Unterschiede als auch intra-individuelle Leistungsentwicklungen in beiden Leistungsbereichen zu bedeutsamen Anteilen durch das metakognitive Wissen der Schülerinnen und Schüler erklärt werden können. Abschließend werden theoretische und praktische Implikationen dieser Befunde diskutiert.
Modellierung von Kompetenzen im Bereich der Bildung: Eine psychologische Perspektive
Authors: Fleischer Jens , Leutner Detlev , Klieme Eckhard
Published: January 2012

Zusammenfassung. Das vorliegende Themenheft umfasst sechs Beiträge aus Projekten des DFG-Schwerpunktprogramms „Kompetenzmodelle zur Erfassung individueller Lernergebnisse und zur Bilanzierung von Bildungsprozessen”. Die Beiträge, die sich mit Aspekten der Kompetenzdomänen „Lehrerkompetenzen”, „Sprache/Lesen” sowie „fächerübergreifende Kompetenzen” beschäftigen, werden im letzten Beitrag des Themenheftes kritisch kommentiert.
Total CO2 output from Vulcano island (Aeolian Islands, Italy)
Authors: Inguaggiato Salvatore , Mazot Agnes , Diliberto Iole Serena , Inguaggiato Claudio , Madonia Paolo , Rouwet Dmitri , Vita Fabio
Published: January 2012

Total CO2 output from fumaroles, soil gas, bubbling gas discharges and water dissolved gases discharged from the island, was estimated for Vulcano island, Italy. The CO2 emission from fumaroles from the La Fossa summit crater was estimated from the SO2 crater output, while CO2 discharged through diffuse soil emission was quantified on the basis of 730 measurements of CO2 fluxes from the soil of the island, performed by using the accumulation chamber method. The results indicate an overall output of ≅500 t day−1 of CO2 from the island. The main contribution to the total CO2 output comes from the summit area of the La Fossa cone (453 t day−1), with 362 t day−1 from crater fumaroles and 91 t day−1 from crater soil degassing. The release of CO2 from peripheral areas is ≅20 t day−1 by soil degassing (Palizzi and Istmo areas mainly), an amount comparable to both the contribution of water dissolved CO2 (6 t day−1), as well as to seawater bubbling CO2 (4 t day−1 measured in the Istmo area). Presented data (September 2007) refer to a period of moderate solphataric activity, when the fumaroles temperature were 450°C and gas/water molar ratio of fumaroles was up to 0.16. The calculated total CO2emission allows the estimation of the mass release and related thermal energy from the volcanic‐hydrothermal system.
Warm Eocene climate enhanced petroleum generation from Cretaceous source rocks: A potential climate feedback mechanism?
Authors: Kroeger K. F. , Funnell R. H.
Published: January 2012

Earth surface temperatures, including in the deep sea increased by 5–10°C from the late Paleocene ca. 58 Myr ago to the Early Eocene Climatic Optimum (EECO) centered at about 51 Myr ago. A large (∼2.5‰) drop in δ13C of carbonate spans much of this interval. This suggests a long‐term increase in the net flux of13C‐depleted carbon to the ocean and atmosphere that is difficult to explain by changes in surficial carbon cycling alone. We reveal a relationship between surface temperature increase and increased petroleum generation in sedimentary basins operating on 100 kyr to Myr time scales. We propose that early Eocene warming has led to a synchronization of periods of maximum petroleum generation and enhanced generation in otherwise unproductive basins through extension of the volume of source rock within the oil and gas window across hundreds of sedimentary basins globally. Modelling the thermal evolution of four sedimentary basins in the southwest Pacific predicted an up to 50% increase in petroleum generation that would have significantly increased leakage of light hydrocarbons and oil degeneration products into the atmosphere. Extrapolating our modelling results to hundreds of sedimentary basins worldwide suggests that globally increased leakage could have caused a climate feedback effect, driving or enhancing early Eocene climate warming.
An assessment of deep steric height variability over the global ocean
Authors: Ponte Rui M.
Published: January 2012

An ocean state estimate constrained by most available data is explored to assess characteristics of variability in deep steric height—a mostly unobserved quantity, yet important for understanding the relation between sea level, heat content and other ocean climate parameters. Results are based on monthly‐averaged steric height anomalies, vertically integrated over the “unobserved” deep ocean (below ∼1700 m). Excluding linear trends, variability in deep steric height is typically 10–20% of that in the upper ocean, with larger values seen in extensive regions. Enhanced deep variability, at monthly to interannual time scales, occurs in areas of strong eddy energy. Deep signals are mostly thermosteric in nature, with halosteric contributions tightly correlated and generally compensating in the Atlantic and Indian oceans and adding in the Pacific. Potential inference of deep signals from knowledge of the upper ocean is hampered by poor correlations, and regressions based on upper ocean steric height fail to represent the estimated deep variability. Monthly sampling at ∼2° scales would allow for best determination of deep variability and long term trends.
Upstream‐generated Pc3 ULF wave signatures observed near the Earth's cusp
Authors: Yeoman T. K. , Wright D. M. , Engebretson M. J. , Lessard M. R. , Pilipenko V. A. , Kim H.
Published: January 2012

Pc3 pulsations (frequency ∼20–100 mHz) which originate in the ion foreshock upstream of the Earth's bow shock due to the interaction between reflected ions and the solar wind are frequently observed in ground‐based pulsation magnetometer data. Previous studies have noted increased Pc3 wave power in the vicinity of the dayside cusp and inferred that the upstream waves gained entry via the cusp, although more recent studies have revealed a more complex picture. Here, we examine Pc3 wave power near local noon observed by search coil magnetometers at three closely‐spaced stations on Svalbard, during times when an extended interval of HF radar backscatter indicative of the cusp is detected by the Hankasalmi SuperDARN radar. The location of the equatorward edge of the HF radar cusp may then be directly compared with the Pc3 wave power measured at three latitudes as the cusp migrates across the stations on a statistical basis. These observations are more consistent with wave entry to the magnetosphere along closed field lines equatorward of the cusp via the ionospheric transistor mechanism of Engebretson et al. (1991a), or weakly coupled fast and Alfvén wave modes, which then map to the low‐latitude boundary layer or outer magnetosphere, rather than with wave entry into the magnetosphere via the cusp proper or exterior cusp.
Impact of the Manaus urban plume on trace gas mixing ratios near the surface in the Amazon Basin: Implications for the NO‐NO2‐O3 photostationary state and peroxy radical levels
Authors: Trebs Ivonne , Mayol‐Bracero Olga L. , Pauliquevis Theotonio , Kuhn Uwe , Sander Rolf , Ganzeveld Laurens , Meixner Franz X. , Kesselmeier Jürgen , Artaxo Paulo , Andreae Meinrat O.
Published: January 2012

We measured the mixing ratios of NO, NO2, O3, and volatile organic carbon as well as the aerosol light‐scattering coefficient on a boat platform cruising on rivers downwind of the city of Manaus (Amazonas State, Brazil) in July 2001 (Large‐Scale Biosphere‐Atmosphere Experiment in Amazonia‐Cooperative LBA Airborne Regional Experiment‐2001). The dispersion and impact of the Manaus plume was investigated by a combined analysis of ground‐based (boat platform) and airborne trace gas and aerosol measurements as well as by meteorological measurements complemented by dispersion calculations (Hybrid Single‐Particle Lagrangian Integrated Trajectory model). For the cases with the least anthropogenic influence (including a location in a so far unexplored region ∼150 km west of Manaus on the Rio Manacapuru), the aerosol scattering coefficient, σs, was below 11 Mm−1, NOx mixing ratios remained below 0.6 ppb, daytime O3 mixing ratios were mostly below 20 ppb and maximal isoprene mixing ratios were about 3 ppb in the afternoon. The photostationary state (PSS) was not established for these cases, as indicated by values of the Leighton ratio, Φ, well above unity. Due to the influence of river breeze systems and other thermally driven mesoscale circulations, a change of the synoptic wind direction from east‐northeast to south‐southeast in the afternoon often caused a substantial increase of σs and trace gas mixing ratios (about threefold for σs, fivefold for NOx, and twofold for O3), which was associated with the arrival of the Manaus pollution plume at the boat location. The ratio Φ reached unity within its uncertainty range at NOx mixing ratios of about 3 ppb, indicating “steady‐state” conditions in cases when radiation variations, dry deposition, emissions, and reactions mostly involving peroxy radicals (XO2) played a minor role. The median midday/afternoon XO2 mixing ratios estimated using the PSS method range from 90 to 120 parts per trillion (ppt) for the remote cases (σs < 11 Mm−1 and NOx < 0.6 ppb), while for the polluted cases our estimates are 15 to 60 ppt. These values are within the range of XO2 estimated by an atmospheric chemistry box model (Chemistry As A Box model Application‐Module Efficiently Calculating the Chemistry of the Atmosphere (CAABA/MECCA)‐3.0).
Influence of atmospheric circulation patterns on the oxygen isotope ratio of tree rings in the Alpine region
Authors: Saurer Matthias , Kress Anne , Leuenberger Markus , Rinne Katja T. , Treydte Kerstin S. , Siegwolf Rolf T. W.
Published: January 2012

The oxygen isotope ratio of precipitation and tree rings is a complex function of climate variables and atmospheric dynamics, which often makes the interpretation of δ18O for palaeoclimate research challenging. Here we analyzed monthly precipitation δ18O series for 1973–2004 and annually resolved tree ring δ18O chronologies for 1945–2004 for three sites in Switzerland: one north of the Alps, one at high‐elevation within the Alps, and one south of the Alps. The goal of the study was to improve the understanding of the tree ring archive by a systematic analysis of nonlocal parameters related to atmospheric circulation, in particular, geopotential height field anomalies and the frequency of synoptic weather situations, in addition to the usual local climate parameters like temperature, sunshine duration, and relative humidity. We observed that on average high‐pressure situations during summer were associated with relatively high δ18O and low‐pressure situations were associated with relatively low δ18O, for both the isotope ratio in precipitation and tree rings. However, correlations to the frequency of weather types were not higher than simple correlations to local temperature. Accordingly, we constructed a combined index from temperature and air pressure that proved to be a good predictor of δ18O in precipitation and used this as the source water term in a tree ring isotope fractionation model. This enabled us to use the model beyond the period where isotope values for precipitation are available, opening new perspectives in the interpretation of long tree ring δ18O chronologies.
Draft U.S. ocean policy plan precedes proposal to move NOAA to Interior department
Authors: Showstack Randy
Published: January 2012

The Obama administration's ambitious plan to protect oceans was released on 12 January, just 1 day prior to the administration's apparently unrelated announcement of a proposed governmental reorganization that would move the National Oceanic and Atmospheric Administration (NOAA) from the Department of Commerce to the Department of the Interior. The proposed NOAA move is part of a larger administration proposal to consolidate six federal agencies that are focused on business and trade into one department. The action is contingent upon congressional approval. The proposal to move NOAA to the Interior department has prompted a variety of reactions, with some considering it common sense to group agencies dealing with natural resources in the same department. Others have charged that the proposed move could blunt NOAA's leading role in protecting oceans, among other concerns.
Steno Google doodle
Authors: Showstack Randy
Published: January 2012

Nicolas Steno, a seventeenth‐century Danish Catholic bishop and scientist, is considered a founder of modern stratigraphy and geology for his work on linking modern shark teeth to objects found in rock formations, among many other studies and writings. Steno, whose non‐Latinized name was Niels Stensen, gained newfound fame as the inspiration for a Google doodle published on 11 January to mark his 374th birthday. The doodle of the Google logo is a rainbow‐colored block letter formation that suggests karst stratigraphic layers chock with fossils and shells. How did Steno end up being honored in this way? “The criteria for selecting a doodle subject are pretty simple: We like to celebrate anything that is geeky, quirky, and artistic,” Google's Jennifer Hom, who drew the doodle, told Eos. “Nicholas Steno happened to be a really geeky and innovative thinker whose work on stratigraphy is also visually interesting. Not only does he relate to our Google culture in that he was a groundbreaking (no pun intended) scientist, his work is also very artistically inspiring.”
Greenhouse gas emissions tool
Authors: Showstack Randy
Published: January 2012

Power plants were the largest stationary source of direct greenhouse gas (GHG) emissions in the United States in 2010, according to data from the Environmental Protection Agency's (EPA) GHG Reporting Program, the agency announced on 11 January. The GHG data set, which includes reports from more than 6700 facilities, provides information that the public can search to identify local sources of emissions and that businesses can use to track emissions. Gina McCarthy, assistant administrator for EPA's Office of Air and Radiation, said the program is “a transparent, powerful data resource available to the public” and that it provides “a critical tool” for businesses and others to find efficiencies to reduce emissions.
AGU Fellows Elected for 2012
Authors: Lui Anthony
Published: January 2012

The AGU Fellows program recognizes members who have made exceptional contributions to the Earth and space sciences. The first class of AGU Fellows was elected in 1962, and AGU bylaws require that the size of a Fellows class be limited to no more than 0.1% of the total AGU membership. During the 2011 Fall Meeting, the AGU Council voted to align the nomination cycles for all Union honors. AGU will accept Fellows nominations for the class of 2013 from 15 January to 15 March 2013 and will announce elected Fellows in July 2013. The individuals listed below have been elected as the 2012 class of Fellows and will be recognized during the honors ceremony at the 2012 AGU Fall Meeting, 6–10 December.
Stratospheric ozone affects mesospheric temperature trends
Authors: Schultz Colin
Published: January 2012

Since 1961, temperatures in the summer mesosphere have undergone a series of reversals. From 1961 to 1979 the atmospheric layer that stretches from roughly 50‐ to 100‐kilometer altitude cooled by 0.5 K per decade. In the subsequent 2 decades the rate of cooling escalated to −3 to −5 K per decade, while the next 10 years saw a mild recovery. Though these temperature flips are seen in the observational record, they have never been reliably re‐created in computer models of the middle atmosphere. Unlike the troposphere or stratosphere, for which there are extensive records, observations of mesospheric temperature are limited to point‐source detections, making accurate modeling particularly important.
Using Loch Ness to track the tilt of the world
Authors: Schultz Colin
Published: January 2012

That the rise and fall of the tide is driven primarily by the gravitational pull of the Moon and the Sun is common knowledge, but not all tides are controlled by such a standard mechanism. Researchers working on Loch Ness in Scotland found that rather than the loch's tide being driven directly by this so‐called astronomical tide, it is also controlled by a process known as ocean tidal loading. Loch Ness lies just 13 kilometers inshore from the North Sea. The astronomical tide redistributes the ocean to such an extent that the changing mass of water along the coast deforms the seafloor. As the ocean tide ebbs and flows, the surface of the Earth rises and falls.
Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak
Authors: Field A. R. , Dunai D. , Gaffka R. , Ghim Y.-c. , Kiss I. , Mészáros B. , Krizsanóczi T. , Shibaev S. , Zoletnik S.
Published: January 2012

A new beam emission spectroscopy turbulence imaging system has recently been installed onto the MAST spherical tokamak. The system utilises a high-throughput, direct coupled imaging optics, and a single large interference filter for collection of the Doppler shifted Dα emission from the ∼2 MW heating beam of ∼70 keV injection energy. The collected light is imaged onto a 2D array detector with 8 × 4 avalanche photodiode sensors which is incorporated into a custom camera unit to perform simultaneous 14-bit digitization at 2 MHz of all 32 channels. The array is imaged at the beam to achieve a spatial resolution of ∼2 cm in the radial (horizontal) and poloidal (vertical) directions, which is sufficient for detection of the ion-scale plasma turbulence. At the typical photon fluxes of ∼1011 s−1 the achieved signal-to-noise ratio of ∼300 at the 0.5 MHz analogue bandwidth is sufficient for detection of relative density fluctuations at the level of a few 0.1%. The system is to be utilised for the study of the characteristics of the broadband, ion-scale turbulence, in particular its interaction with flow shear, as well as coherent fluctuations due to various types of MHD activity.
Prediction of vibrational frequencies of possible intermediates and side products of the methanol synthesis on ZnO($000\overline{1}$0001¯) by ab initio calculations
Authors: Koßmann Jörg , Roßmüller Guido , Hättig Christof
Published: January 2012

We used ab initio density functional theory in combination with an embedded cluster approach to calculate vibrational spectra and formation enthalpies of possible intermediates and side products (spectator species) in the synthesis of methanol out of syngas on the ZnO(\documentclass[12pt]{minimal}\begin{document}$000\overline{1}$\end{document}0001¯) surface. Our investigations are based upon our previous work on possible reaction pathways and activation barriers for this reaction at oxygen vacancies on ZnO(\documentclass[12pt]{minimal}\begin{document}$000\overline{1}$\end{document}0001¯). We present and discuss calculated vibrational frequencies of short-living formyl, hydroxymethylene, formaldehyde, acetale, and hydroxymethyl intermediates and compare the calculated frequencies of formate and methoxy species as well as CO and CO2 species, at the defect free surface and at oxygen vacancies, with recent experimental findings. All investigated species show characteristic features in their spectra. Therefore, the analysis of their vibrational frequencies is a suitable mean to distinguish them and gain new insights in this reaction which is of recent experimental interest. We are able to identify the structure and characteristics of different surface species, such as monodentate and polydentate carbonate and formate species, in agreement with experimental results.
Turbulence driven particle transport in Texas Helimak
Authors: Toufen D. L. , Guimarães-Filho Z. O. , Caldas I. L. , Marcus F. A. , Gentle K. W.
Published: January 2012

We analyze the turbulence driven particle transport in Texas Helimak [K. W. Gentle and H. He, Plasma Sci. Technol. 10, 284 (2008)], a toroidal plasma device with a one-dimensional equilibrium with magnetic curvature and shear. Alterations on the radial electric field, through an external voltage bias, change the spectral plasma characteristics inducing a dominant frequency for negative bias values and a broad band frequency spectrum for positive bias values. When applying a negative bias, the transport is high where the waves propagate with phase velocities near the plasma flow velocity, an indication that the transport is strongly affected by a wave particle resonant interaction. On the other hand, for positive bias values, the plasma has a reversed shear flow, and we observe that the transport is almost zero in the shearless radial region, an evidence of a transport barrier in this region.