1,130 research outputs found

    Deformable plate tectonic models of the southern North Atlantic

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    Significant, poly-phase deformation occurred prior to, simultaneous with, and after the opening of the North Atlantic Ocean. Understanding this deformation history is essential for understanding the regional development and the mechanisms controlling rifting and subsequent failure or breakup. Here, we primarily use published constraints to construct deformable plate tectonic models for the southern North Atlantic from 200 Ma to present using GPlates. The aim of this work is to test both the capability of the GPlates deformable modelling approach and the reliability of published plate reconstructions. Overall, modelled crustal thickness values at 0 Ma produced from the deformable models show general, regional-scale, similarities with values derived from the inversion of gravity data for crustal thickness. However, the deformable models typically underestimate thinning in marginal basins and overestimate crustal thickness in continental fragments compared to values from gravity inversion. This is possibly due to: 1) thinning occurring earlier than the 200 Ma start time modelled, 2) variations in the original crustal thickness, 3) depth-dependent stretching, 4) rigid blocks undergoing some degree of thinning, and 5) variations in the mesh density of the models. The results demonstrate that inclusion of micro-continental fragments, and locally defined limits of continental crust, generally produce results more akin to observations. One exception is the Grand Banks where global GPlates models produce more realistic deformation, likely due to the inclusion of the exhumed domains continent-ward of the transition zone boundary. Results also indicate that Flemish Cap rotation is required to provide a reasonable fit between North America and Iberia, with the palaeo-position of the Flemish Cap likely to be the proto-Orphan sub-basins. Moreover, the East and West Orphan sub-basins formed separately due to the respective rotations of the Flemish Cap and the Orphan Knoll, which was likely associated with other continental fragments that subsequently contributed to the thicker crust forming the boundary between the East and West Orphan basins. The results also suggest a link between tectonic and magmatic processes. For example, the inclusion of an Orphan Knoll micro-continental block results in greater extension (higher beta factors) in the northern West Orphan Basin near the termination of the Charlie-Gibbs Fracture Zone, and the site of the Charlie-Gibbs Volcanic Province (CGVP). Thus, we infer that the CGVP was likely influenced by plate tectonic processes through the concentration of strain resulting from interaction in proximity to the transform system. Finally, marginal basins that were considered to be conjugate and thus related, may only appear conjugate through later rotation of micro-continental blocks, and thus their genesis is not directly related

    Researching recovery from psychosis: a user-led project

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    Phase Coherence and Superfluid-Insulator Transition in a Disordered Bose-Einstein Condensate

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    We have studied the effects of a disordered optical potential on the transport and phase coherence of a Bose-Einstein condensate (BEC) of 7Li atoms. At moderate disorder strengths (V_D), we observe inhibited transport and damping of dipole excitations, while in time-of-flight images, random but reproducible interference patterns are observed. In-situ images reveal that the appearance of interference is correlated with density modulation, without complete fragmentation. At higher V_D, the interference contrast diminishes as the BEC fragments into multiple pieces with little phase coherence.Comment: 4 pages, 5 figures, distortions in figures 1 and 4 have been fixed in version 3. This paper has been accepted to PR

    Using a smartphone ‘app’ in qualitative research: the good, the bad and the ugly

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    This paper reflects on the use of a smartphone application (‘app’) in qualitative research following the experience of the FREE (Football Research in an Enlarged Europe) project, which investigated the lives of football fans in the UK. To meet this aim, a participant-focused audio-visual methodology was designed, featuring the use of an app to collect data. Fans were asked to take photographs and keep diaries to show the role football plays in their lives. The smartphone app was developed to allow fans to use their own mobile phones, capturing qualitative data in ‘real time’. The paper reflects on our experience of using the smartphone app in this qualitative research, analysing the advantages, disadvantages and the main risks that researchers will need to take into account when using smartphone apps in their future qualitative research projects. We encourage others to build on and advance this under-researched but potentially valuable tool

    A ‘healthy’ future? Supporters’ perceptions of the current state of English football

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    Over the last few years clear public policy support in favour of fan engagement in the governance of football has developed. This is based on the assumption that supporters are dissatisfied with the current governance structures within the sport. There is, however, no robust academic evidence of whether this is indeed the case. This article aims to contribute to the debate by presenting data from qualitative fieldwork with 21 football supporters during March-May 2013. Each participant created a photograph album over an eight-week period, and was then interviewed individually to elicit the meaning of their photographs and diaries. This group of fans used their photographs to express dissatisfaction with several aspects of current football governance, highlighting issues with the financial, physical and social health of the sport. We suggest a number of implications of this, both for the fans and for the future state of the game

    The Generalized Stochastic Microdosimetric Model: the main formulation

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    The present work introduces a rigorous stochastic model, named Generalized Stochastic Microdosimetric Model (GSM2), to describe biological damage induced by ionizing radiation. Starting from microdosimetric spectra of energy deposition in tissue, we derive a master equation describing the time evolution of the probability density function of lethal and potentially lethal DNA damage induced by radiation in a cell nucleus. The resulting probability distribution is not required to satisfy any a priori assumption. Furthermore, we generalized the master equation to consider damage induced by a continuous dose delivery. In addition, spatial features and damage movement inside the nucleus have been taken into account. In doing so, we provide a general mathematical setting to fully describe the spatiotemporal damage formation and evolution in a cell nucleus. Finally, we provide numerical solutions of the master equation exploiting Monte Carlo simulations to validate the accuracy of GSM2. Development of GSM2 can lead to improved modeling of radiation damage to both tumor and normal tissues, and thereby impact treatment regimens for better tumor control and reduced normal tissue toxicities

    Photoassociation of a Bose-Einstein Condensate near a Feshbach Resonance

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    We measure the effect of a magnetic Feshbach resonance (FR) on the rate and light-induced frequency shift of a photoassociation resonance in ultracold 7^7Li. The photoassociation-induced loss rate coefficient, KpK_p, depends strongly on magnetic field, varying by more than a factor of 104^4 for fields near the FR. At sufficiently high laser intensities, KpK_p for a thermal gas decreases with increasing intensity, while saturation is observed for the first time in a Bose-Einstein condensate. The frequency shift is also strongly field-dependent and exhibits an anomalous blue-shift for fields just below the FR.Comment: 4 pages, 4 figures. v2: updated comparison with theory; added references; added tick marks to Fig. 1 inset. To be published in Phys. Rev. Letter

    The determinants of hotels' marketing managers' green marketing behaviour

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    Little is known about the factors underlying the pro-environmental behaviour of marketing managers. This paper explores the determinants of green marketing practices in the Red Sea hotel sector in Egypt. The research model assesses green marketing practices against the personal and organisational values of the marketing managers, together with a range of organisational and demographic variables expected to influence hotels' environmental behaviour. From a valid sample of 89 marketing managers responsible for 194 hotels, it was found that organisational contextual variables, and in particular targeting Western tourists, being affiliated to an international hotel chain and the marketers' own demographics, including age, academic subject studied and gender, were the best predictors of more proactive green marketing. Personal environmental values did not explain the pro-environmental behaviour of marketers, and the organisational environmental values that had explained part of their ethical behaviour had resulted from voluntarism rather than utilitarian or conformance-based values. Government policies also appeared to be ineffective determinants. The implications for green marketing practices are also discussed. © 2010 Taylor & Francis

    Nachweis von PAK-metabolisierenden Mikroorganismen durch kulturelle und molekularbiologische Verfahren

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    Zielsetzung der Arbeit war der Nachweis von PAK-abbauenden Mikroorganismen in Umweltproben mittels klassischer mikrobiologischer Arbeitstechniken und molekular-biologischer Methoden. Durch selektive Anreicherung wurden Bakterien mit der Fähigkeit Polyzyklische Aromatische Kohlenwasserstoffe (PAK) abzubauen, in aquatischen und terrestrischen Umweltproben nachgewiesen. Unabhängig von der Belastung der Standorte mit PAK wurden aus allen untersuchten Habitaten Bakterien isoliert, die mit Naphthalin oder Phenanthren als alleiniger Kohlenstoff- und Energiequelle wachsen konnten. Die 23 isolierten PAK-abbauenden Bakterien konnten als Mitglieder der Gattungen Sphingomonas, Acidovorax, Comamonas, Pseudomonas, Rhodococcus und Paenibacillus identifiziert werden und waren somit den alpha-, beta- und gamma-Subklassen der Proteobakterien und den Entwicklungslinien der grampositiven Bakterien mit hohem und niedrigem GC-Gehalt der DNA zuzuordnen. Die größte Gruppe bildeten mit 10 der 23 Isolate Vertreter der Gattung Pseudomonas, die alle Naphthalin metabolisierten. Die Quantifizierung des Naphthalin-Abbaus mittels gaschromatographischer Verfahren zeigte, daß in Flüssigmedium vorhandenes kristallines Naphthalin (0,05%, w/v) von den meisten Stämmen nach nur zwei Tagen Kultivierungsdauer vollständig metabolisiert wurde. Die getesteten Rhodococcus Isolate bauten Naphthalin wesentlich langsamer ab, als die verschiedenen Isolate, die den Proteobakterien zugeordnet wurden. Der dreikernige Aromat Phenanthren wurde von den getesteten Bakterienstämmen langsamer abgebaut als Naphthalin. Innerhalb von fünf Tagen wurde die Phenanthrenmenge im Medium auf 40-60% der Ausgangsmenge reduziert. Die Untersuchung des Naphthalinabbaus durch Zellen, die zuvor in Naphthalin-haltigem Medium bzw. in Vollmedium vorkultiviert worden waren, ergab, daß die Enzyme für den Abbau von Naphthalin in Abwesenheit eines Induktors nicht exprimiert wurden. Ebenso zeigte sich, daß Zellen, die in Medium mit Naphthalin oder Phenanthren kultiviert wurden, wesentlich höhere Catechol 2,3-Dioxygenase (C23O)-Aktivitäten aufwiesen als in Voll-medium gewachsene Zellen. Zum Nachweis von PAK-Abbauern auf molekulargenetischer Ebene wurden, basierend auf bekannten Sequenzen, PCR-Primer und Oligonukleotidsonden für codierende Abschnitte der C23O entwickelt, und, in Kombination mit Primern und Oligonukleotidsonden, zur Detektion der initialen PAK-Dioxygenase (entwickelt von R. Moser, TU-Berlin), eingesetzt. Mit den entworfenen Primern und Sonden konnten die C23O-Sequenzabschnitte bei allen PAK-abbauenden Referenzstämmen und Isolaten, die der Gattung Pseudomonas und Sphingomonas zugehörten, spezifisch detektiert werden. Durch die Anwendung spezifischer Primer und Sonden konnten dabei die Gene der C23O für Vertreter der Pseudomonaden und Sphingomonaden getrennt voneinander erfaßt werden. Sequenzanalysen der erhaltenen PCR-Amplifikate zeigten, daß die C23O-Gene innerhalb der Gattungen Pseudomonas bzw. Sphingomonas mit über 75% Sequenzähnlichkeit sehr gut konserviert sind. Dagegen waren Sequenzen der katabolischen Gene der PAK-abbauenden Comamonas-, Acidovorax- oder Rhodococcus-Vertreter offensichtlich zu verschieden, verglichen mit den Pseudomonas- und Sphingomonas-Sequenzen, um sie mittels der entwickelten Primer und Sonden detektieren zu können. Die Diversität der C23O zeigte sich auch bei der spezifischen enzymatischen Aktivität, die im Bereich von 0,1 bis 650 mU mg-1 Protein variierte. Dabei wurde die höchste spezifische Aktivität für verschiedene Pseudomonas-Stämme nachgewiesen. Die entwickelten Primer wurden auf ihre Anwendbarkeit getestet, PAK-abbauende Bakterien in Umweltproben kultivierungsunabhängig zu detektieren. Verschiedene DNA-Isolierungsmethoden und Techniken zur Aufreinigung der isolierten DNA wurden getestet und variiert. Bei der DNA-Isolierung aus Belebtschlammproben wurden Substanzen coextrahiert, die stark hemmenden Einfluß auf die PCR hatten. Die weitere Aufreinigung der DNA führte zu starken Verlusten der ursprünglichen DNA-Mengen und damit zu einer Reduzierung der zu detektierenden Zielsequenzen. Die extrahierte und gereinigte DNA aus unterschiedlichen Belebtschlammproben wurde in der PCR zur Detektion von initiale Dioxygenase- und C23O-codierenden Genabschnitten eingesetzt. Während codierende Bereiche der initialen Dioxygenase in der Belebtschlammprobe der Kläranlage Gießen mit den entwickelten Primern nachgewiesen werden konnten (R. Moser, TU-Berlin), wurden bei der Verwendung der C23O-spezifischen Primer keine PCR-Amplifikate erhalten. Offensichtlich lag die Zahl der C23O-Zielsequenzen in den untersuchten Umweltpoben unterhalb des Detektionslimits. In der extrahierten DNA aus anderen Belebtschlammproben konnten C23O-codierende Abschnitte detektiert werden. Die erhaltenen PCR-Amplifikate waren aber in allen Fällen sehr schwach. Die Ergebnisse zeigen, daß zur Detektion von katabolischen Genen, die in geringen Konzentrationen in Umweltproben vorliegen, spezielle Methoden zur Aufreinigung der DNA-Rohextrakte etabliert werden müssen
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