3,035 research outputs found

    Performance of Photon-Pair Quantum Key Distribution Systems

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    We analyze the quantitative improvement in performance provided by a novel quantum key distribution (QKD) system that employs a correlated photon source (CPS) and a photon-number resolving detector (PNR). Our calculations suggest that given current technology, the CPR implementation offers an improvement of several orders of magnitude in secure bit rate over previously described implementations

    Why Write Fantasy? A Mythopoeic Conference XIV Panel

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    The purpose of this panel is to examine some of the underlying reasons why Fantasy literature is written and why it is worth writing. Many of us, probably most of us, as readers of Fantasy, have been tempted to try our own hand at writing Fantasy at one time or another. The panelists here today will hopefully be able to give us some direction for those story ideas we feel we must try to get down on paper. Our honored guests are Marion Zimmer Bradley, author of the Darkover series and the Mists of Avalon; Diana Paxon, author of Lady of Light and Lady of Darkness; Stephen Donaldson, author of the Chronicles of Thomas Covenant ; and Evangeline Walton author of The Song of Rhiannon, The Childern of Llyr, The Island of the Mighty, Prince of Annwn, and is now completing a new series of books based on the Greek Myths

    A truncated inner disc in the Seyfert 1 galaxy WKK 4438

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    Understanding if and when the accretion disc extends down to the innermost stable circular orbit (ISCO) is important since it is the fundamental assumption behind measuring black hole spin. Here, we examine the 2013 and 2018 NuSTAR and Swift data (0.5 - 50 keV) of the narrow-line Seyfert 1 galaxy, WKK 4438. The X-ray emission can be fitted well with models depicting a corona and blurred reflection originating from a disc around a low spin (a* ~ 0) black hole. However, such models result in unconventional values for some of the parameters (e.g. inverted emissivity profile and high coronal height). Alternatively, equally good fits can be achieved if the disc is truncated at ~10 rg and the black hole is spinning at the Thorne limit (a* = 0.998). In these cases, the model parameters are consistent with the interpretation that the corona is centrally located close to the black hole and illuminating the disc at a larger distance.Comment: 8 pages, 5 figures. Accepted for publication in MNRA

    Molecular Analysis of a Major Carpel Developmental Regulator: CRABS CLAW’s Protein Domains and Non-Cell-Autonomous Action

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    CRABS CLAW is a small protein belonging to the YABBY family, a plant specific protein family. In Arabidopsis thaliana it is expressed in the developing carpels and regulates the apical fusion of the two carpels, transmitting tract development, lateral growth, and nectary formation. The expression of CRC is rather complex with multiple expression domains throughout the young gynoecium and as for other YABBY proteins a non-cell-autonomous action has been described. However, only few regulators of CRC expression and target genes are described and the mode of non-cell-autonomous action is still unknown. This dissertation aims to identify transcriptional regulators, responsible for the proper temporal and spatial expression of CRC, the specification of CRC’s place in the adaxial-abaxial regulatory network and to clarify the means of its non-cell-autonomous action. The regulation of CRC expression has been analyzed via a large scale Yeast-1-Hybrid screen and identified over 100 potential regulators of CRC expression, integrating CRC tightly into the carpel developmental regulatory protein network. Further analysis of CRC function through expression analysis led to the identification of target genes of CRC like mir165/166, members of the KANADI gene family, and the HD ZIP III gene family. Both gene families are major players in the adaxial-abaxial regulatory network, involved in the development of all lateral plant organs such as leaves and floral organs. CRC supports KANADI action and activates the expression of other involved factors. In addition, CRC directly targets members of the HD ZIP III family. However, CRC’s position in the adaxial- abaxial regulatory network seems to be not conserved in other eudicots. CRC exhibits a non- cell-autonomous action which is conferred by at least two signaling pathways. Abaxial polarity is regulated by the activation of the mobile miRNA165/166. At the same time, localizations of GFP tagged CRC revealed the CRC protein to be mobile as it migrates into the adaxial domain in young gynoecia. In older gynoecia it was excluded from the adaxial domain. This study identified multiple unique features of CRC compared to its relatives. Its thightly controlled expression by over 100 putative regulators, integration in complex co-expression networks, adaxial and abaxial target genes, and its two mode non-cell-autonomous action indicate the important role in the complicated carpel development.CRABS CLAW ist ein kleines Protein der pflanzenspezifischen YABBY Protein Familie. In Arabidopsis thaliana ist es in den entwickelnden FruchtblĂ€ttern exprimiert und reguliert die apikale Fusion der FruchtblĂ€tter, die Entwicklung des Transmissionskanal (einem Bereich des Septums), die Begrenzung des lateralen Wachstums des Gynoeceums, und die Bildung der Nektarien. Die Expression von CRC ist auf mehrere Bereiche im Fruchtblatt aufgeteilt und ebenso wurde ein nicht-zell-autonomer Effekt wie fĂŒr andere YABBY Proteine beschrieben. Jedoch sind nur einige wenige Regulatoren der CRC Expression und Zielgene von CRC bekannt, sowie die Natur des mobilen Signals des nicht-zell-autonomen Effektes unbekannt ist. Daher zielt diese Dissertation darauf, zusĂ€tzliche transkriptionelle Regulatoren, die fĂŒr die korrekte zeitliche und rĂ€umliche Expression von CRC nötig sind, zu identifizieren, sowie CRCs Position im adaxialen-abaxialen Netzwerk zu identifizieren und die Art und Weise des nicht-zell-autonomen Effektes zu klĂ€ren. Die Expression von CRC wurde durch eine groß angelegte Hefe-1-Hybrid Analyse nĂ€her untersucht und ĂŒber 100 mögliche Regulatoren der CRC Expression wurden identifiziert. Dies festigt CRCs Position im gen-regulatorischen Netzwerk der Fruchtblattentwicklung. Eine weitere Analyse der CRC Funktionen mittels Expressionsanalyse fĂŒhrte zu der Identifikation mehrerer Zielgene wie mir165/166, Mitglieder der KANADI Genfamilie und Mitglieder der HD ZIP III Genfamilie. Beide Genfamilien sind Hauptkomponenten des adaxial–abaxialen Regulationsnetzwerkes. Dabei unterstĂŒtzt CRC die Funktion der KAN Proteine und reguliert die Expression anderer involvierter Gene. ZusĂ€tzlich reguliert CRC direkt die Expression einiger HD ZIP III Gene. Wobei die Regulation der adaxial-abaxialen Regulatoren durch CRC zwischen verschiedenen Eudikotylen nicht komplett konserviert ist. CRC weist eine nicht-zell-autonome Funktion auf, die durch mindestens zwei SignalĂŒbertragungswege vermittelt wird. Zum einen reguliert CRC die abaxiale PolaritĂ€t durch die Aktivierung der mobilen miRNA165/166 und zum anderen durch direkten Transport des CRC Proteins. Lokalisierungen von mit GFP markierten CRC zeigten, dass das CRC Protein in den frĂŒhen Stadien des Gyneoceums von der abaxialen DomĂ€ne in die adaxiale wandert. In spĂ€teren Stadien ist CRC auf die abaxiale DomĂ€ne begrenzt. Diese Studie konnte mehrere einzigartige CRC Charakteristika identifizieren, die CRC von den anderen Mitgliedern der YABBY Familie unterscheidet. Seine stark kontrollierte Expression durch mehr als 100 mögliche Regulatoren, die Integration in ein kompliziertes Co- Expressions Netzwerk, adaxiale und abaxiale Zielgene, und mindestens zwei Möglichkeiten zur nicht-zell-autonomen Regulation, zeigen eindringlich die wichtige Rolle CRCs in der komplexen Karpellentwicklung auf

    Stratified horizontal flow in vertically vibrated granular layers

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    A layer of granular material on a vertically vibrating sawtooth-shaped base exhibits horizontal flow whose speed and direction depend on the parameters specifying the system in a complex manner. Discrete-particle simulations reveal that the induced flow rate varies with height within the granular layer and oppositely directed flows can occur at different levels. The behavior of the overall flow is readily understood once this novel feature is taken into account.Comment: 4 pages, 6 figures, submitte

    The employee as 'Dish of the Day’:human resource management and the ethics of consumption

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    This article examines the ethical implications of the growing integration of consumption into the heart of the employment relationship. Human resource management (HRM) practices increasingly draw upon the values and practices of consumption, constructing employees as the ‘consumers’ of ‘cafeteria-style’ benefits and development opportunities. However, at the same time employees are expected to market themselves as items to be consumed on a corporate menu. In relation to this simultaneous position of consumer/consumed, the employee is expected to actively engage in the commodification of themselves, performing an appropriate organizational identity as a necessary part of being a successful employee. This article argues that the relationship between HRM and the simultaneously consuming/consumed employee affects the conditions of possibility for ethical relations within organizational life. It is argued that the underlying ‘ethos’ for the integration of consumption values into HRM practices encourages a self-reflecting, self-absorbed subject, drawing upon a narrow view of individualised autonomy and choice. Referring to Levinas’ perspective that the primary ethical relation is that of responsibility and openness to the Other, it is concluded that these HRM practices affect the possibility for ethical being

    Revisiting (inclusive) education in the postcolony

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    Abstract: This article uses a dialogic approach to explore the complex state of education in the postcolony. It revisits the subject of educational inclusion (and exclusion) and interrogates different epistemological and systemic framings of what constitutes education and knowledge, and the effects that these have on the postcolonial educa- tional landscape. The authors ask troubling questions of the ways that the largely Eurocentric conceptualisations of these issues, and the baggage of colonial(ism/ity) can and do affect the design and delivery of education in these settings. The use of a metalogue as a methodological approach allows the contributors to jointly ponder the issues from different perspectives and positionalities, and in a way that honours their individual voices
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