14,269 research outputs found

    Displaying Lives: the Narrative of Objects in Biographical Exhibitions

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    Biographical exhibitions are a museum practice that asks for critical consideration. Grounding the argument in critical theory, social studies and museum theory, the article explores the narrative function of objects in biographical exhibitions by addressing the social significance of objects in relation to biography and their relevance when presented into an exhibition display. Central is the concept of objects as ‘biographical relics’ that are culturally fetishized in biographical narratives. This raises questions about biographical reliability and the cultural role that such objects plays in exhibition narratives as bearers of reality and as metonymical icons of the biographical subject. The article considers examples of biographical exhibitions of diverse figures such as Gregor Mendel, Madame de Pompadour and Roland Barthes, and the role that personal items, but also portraits and photographs, play in them

    The collusive drawbacks of sequential auctions

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    Sequential first-price auctions for multiple objects are very common in procurement, electricity, tobacco, timber, and oil lease markets. In this paper we identify two ways in which a sequential format may facilitate collusion among bidders relative to a simultaneous one. The first effect relates to the cartel’s ability to identify and punish defectors within the sequence, thus lowering the gains from a deviation with respect to a simultaneous format. The second effect concerns the cartel’s ability to allocate the bidder with the highest incentive to deviate (the ‘maverick’) to the last object of the sequence, thus increasing the viability of the collusive agreement. We then analyze how the seller may counteract this two effects by limiting the amount of information disclosed to bidders across rounds, and find that partial disclosure policies have little impact on the sustainability of collusion

    Transport of BMAA into Neurons and Astrocytes by System x\u3csub\u3ec\u3c/sub\u3e-

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    The study of the mechanism of β-N-methylamino-l-alanine (BMAA) neurotoxicity originally focused on its effects at the N-methyl-d-aspartate (NMDA) receptor. In recent years, it has become clear that its mechanism of action is more complicated. First, there are certain cell types, such as motor neurons and cholinergic neurons, where the dominate mechanism of toxicity is through action at AMPA receptors. Second, even in cortical neurons where the primary mechanism of toxicity appears to be activation of NMDA receptors, there are other mechanisms involved. We found that along with NMDA receptors, activation of mGLuR5 receptors and effects on the cystine/glutamate antiporter (system xc-) were involved in the toxicity. The effects on system xc- are of particular interest. System xc- mediates the transport of cystine into the cell in exchange for releasing glutamate into the extracellular fluid. By releasing glutamate, system xc- can potentially cause excitotoxicity. However, through providing cystine to the cell, it regulates the levels of cellular glutathione (GSH), the main endogenous intracellular antioxidant, and in this way may protect cells against oxidative stress. We have previously published that BMAA inhibits cystine uptake leading to GSH depletion and had indirect evidence that BMAA is transported into the cells by system xc-. We now present direct evidence that BMAA is transported into both astrocytes and neurons through system xc-. The fact that BMAA is transported by system xc- also provides a mechanism for BMAA to enter brain cells potentially leading to misincorporation into proteins and protein misfolding

    Non-equilibrium wetting transition in a magnetic Eden model

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    Magnetic Eden clusters with ferromagnetic interaction between nearest-neighbor spins are grown in a confined 2d-geometry with short range magnetic fields acting on the surfaces. The change of the growing interface curvature driven by the field and the temperature is identified as a non-equilibrium wetting transition and the corresponding phase diagram is evaluated.Comment: 11 pages, 6 figure

    Interfacial phase transitions in a far-from-equilibrium magnetic growth model

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    The irreversible growth of a magnetic film with spins having two possible orientations is studied in three-dimensional confined geometries of size L×L×ML\times L\times M, where MLM\gg L is the growing direction. A competing situation with two opposite short range surface magnetic fields HH of the same magnitude is analyzed. Due to the antisymmetric condition considered, an interface between domains with spins having opposite orientations develops along the growing direction. Such an interface undergoes a localization-delocalization transition that is the precursor of a wetting transition in the thermodynamic limit, in qualitative agreement with observations performed under equilibrium conditions. However, in contrast to its equilibrium counterparts, the film also exhibits a growing interface that undergoes a concave-convex transition in the growth mode. The phase diagram on the HH versus TT plane is first obtained for a finite system, and exhibits eight different regions. Subsequently, the phase diagram corresponding to the thermodynamic limit is obtained by extrapolation. It is shown that in the latter only six regions remain. The relevant physical properties of all of these regions are discussed in detail.Comment: 22 pages, 10 figure

    Smarter grid through collective intelligence: user awareness for enhanced performance

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    This paper examines the scenario of a university campus, and the impact on energy consumption of the awareness of building managers and users (lecturers, students and administrative staff).Peer ReviewedPostprint (published version

    Dihedral Monodromy and Xiao Fibrations

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    We construct three new families of fibrations π:SB\pi : S \to B where SS is an algebraic complex surface and BB a curve that violate Xiao's conjecture relating the relative irregularity and the genus of the general fiber. The fibers of π\pi are certain \'etale cyclic covers of hyperelliptic curves that give coverings of P1P^1 with dihedral monodromy. As an application, we also show the existence of big and nef effective divisors in the Brill-Noether range.Comment: 12 pages. Exposition improved. The last section has been expanded with more details of the proof. Accepted for publication in Ann. Mat. Pura App

    Development and Evaluation of the Nebraska Assessment of Computing Knowledge

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    One way to increase the quality of computing education research is to increase the quality of the measurement tools that are available to researchers, especially measures of students’ knowledge and skills. This paper represents a step toward increasing the number of available thoroughly-evaluated tests that can be used in computing education research by evaluating the psychometric properties of a multiple-choice test designed to differentiate undergraduate students in terms of their mastery of foundational computing concepts. Classical test theory and item response theory analyses are reported and indicate that the test is a reliable, psychometrically-sound instrument suitable for research with undergraduate students. Limitations and the importance of using standardized measures of learning in education research are discussed
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