391 research outputs found
Convergence of clock processes on infinite graphs and aging in Bouchaud's asymmetric trap model on
Using a method developed by Durrett and Resnick [22] we establish general
criteria for the convergence of properly rescaled clock processes of random
dynamics in random environments on infinite graphs. This complements the
results of [26], [19], and [20]: put together these results provide a unified
framework for proving convergence of clock processes. As a first application we
prove that Bouchaud's asymmetric trap model on exhibits a normal
aging behavior for all . Namely, we show that certain two-time
correlation functions, among which the classical probability to find the
process at the same site at two time points, converge, as the age of the
process diverges, to the distribution function of the arcsine law. As a
byproduct we prove that the fractional kinetics process ages
Irrelevance and Evaluation: Two Arguments Against Gauthier\u27s Contractarianism
This paper provides two arguments against David Gauthierâs version of contractarianism, presented to weaken the cumulative case for this view. Gauthier provides a test for which moral claims are justified: a hypothetical agreement. This agreement consists of those constraints that rational persons would accept. A good many of our moral claims actually fail this test. But despite this fact, complying with justified moral claims makes us better off. By doing so, we are able to gain the benefits of cooperation, available only to those who cooperate. Gauthier thus provides us with a theory of morals by agreement. The first argument of the present paper is as follows. If, upon making this hypothetical agreement, we come to realize that the terms of the agreement itself rely on a conception of morality that is not the object of agreement, we will come to view the agreement as unstable. To re-establish the agreement on more stable grounds, each party to it will, Gauthier supposes, consider which moral claims each would accept in a pre-moral, pre-social situation. The agreement, since it then proceeds from a situation that escapes prior influence of any moral conception, will be a purer, or more stable, test for morality. I will argue that were we to imagine ourselves in such a situation, the resulting imagined person would be quite foreign to ourselves. This hypothetical person, then, becomes the party to the agreement instead of us. The constraints that she would choose in such a situation then appear irrelevant to us. Since these constraints form the agreement, the agreement turns out to be irrelevant to us. The second argument: Gauthier argues that morality faces a foundational crisis and that contractarianism is the only plausible resolution of it. I will argue that this resolution implies an implausible consequence regarding moral evaluation. Moral rationalism is presented and then bolstered as a superior view to contractarianism. With moral rationalism established, it becomes clear that Gauthierâs resolution is implausible. I conclude with some comments about answering the moral skeptic; it may not be the role of the moral philosopher to do this
Time consistency of multi-period distortion measures
Dynamic risk measures play an important role for the acceptance or non-acceptance of risks in a bank portfolio. Dynamic consistency and weaker versions like conditional and sequential consistency guarantee that acceptability decisions remain consistent in time. An important set of static risk measures are so-called distortion measures. We extend these risk measures to a dynamic setting within the framework of the notions of consistency as above. As a prominent example, we present the Tail-Value-at-Risk (TVaR
Das Kiefergelenk
Das Ziel der vorliegenden Untersuchung war es, den trabekulĂ€ren Aufbau des menschlichen Caput mandibulae darzustellen und anhand der knöchernen Struktur RĂŒckschlĂŒsse auf die stattgefundene Belastung zu ziehen. Mit zunehmendem Alter und dem Verlust der ZĂ€hne nimmt die Kaufunktion ab. Damit sollte auch eine VerĂ€nderung -Verringerung- der Belastung der Kondylen einhergehen. Aus diesem Grund wurden die Kondylen von Bezahnten und Zahnlosen gewĂ€hlt, um zwei möglichst unterschiedliche Belastungssituationen wiederzugeben. Mittels des ”CT wurden die Kondylen in toto analysiert und die strukturellen trabekulĂ€ren Parameter erhoben, sowie dreidimensionale Rekonstruktionen erstellt. Nach den Ergebnissen dieser Untersuchung scheint eine durchaus hohe Belastung im menschlichen Kiefergelenk gegeben zu sein. Entgegen aller Annahmen bleibt auch bei den unbezahnten PrĂ€paraten die Kiefergelenkstruktur belastet. Die Belastung scheint jedoch anders verteilt als bei noch vorhandener Bezahnung. Dieser Schluss konnte aus dem Unterschied im Anisotropiegrad gezogen werden. Durch vereinfachte Kaumuster und dadurch weniger Variation in der Belastungsrichtung erscheint die Struktur der Kondylen von zahnlosen Mandibeln weniger anisotrop. Da sich die trabekulĂ€re Struktur bei vier Gelenkpaaren als verĂ€ndert herausstellte, wurden diese getrennt von den anderen betrachtet. Bei diesen konnten neben exophytischen Aufwerfungen an der GelenkoberflĂ€che und Verdickungen der Kompakta auch bei der Mikrostruktur der trabekulĂ€ren Zone Unterschiede beobachtet werden. Verdickungen der vorhandenen Trabekel fĂŒhrten bei gleich bleibender Trabekelanzahl zu einer Erhöhung der Packungsdichte. Auch auf die Substantia compacta und deren Dicke im mittleren Kondylenanteil in antero-posteriorer Richtung wurde nĂ€her eingegangen. Beim Vergleich der Ergebnisse der Kompaktadicke und der Parameter der trabekulĂ€ren Knochenschicht direkt darunter konnten keine Ăbereinstimmungen gefunden werden. Die dreidimensionalen Rekonstruktionen der Kondylen wurden fĂŒr eine Bewertung der makroskopischen Form der Gelenkköpfe herangezogen. Dabei konnte festgestellt werden, dass eine groĂe Formvielfalt gegeben ist. Die Unterschiede zur Grundform werden als Zeichen stetig stattfindender Anpassung bewertet. Die klinische Relevanz dieser Untersuchung liegt zwar nicht in der Verbesserung chirurgischer Verfahren und auch nicht in der Verhinderung von krankhaften VerĂ€nderungen am Kondylus. Die Ergebnisse können aber dazu beitragen, das Wissen ĂŒber diese Gelenkstruktur zu erweitern und damit zur KlĂ€rung des Problemkreises Kiefergelenk und seiner Dysfunktionen beisteuern
Building the Clinical Bridge to Advance Education, Research, and Practice Excellence
The University of Michigan School of Nursing and the Health System partnered to develop an undergraduate clinical education model as part of a larger project to advance clinical education, practice, and scholarship with education serving as the clinical bridge that anchors all three areas. The clinical model includes clusters of clinical units as the clinical home for four years of a student's education, clinical instruction through team mentorship, clinical immersion, special skills preparation, and student portfolio. The model was examined during a one-year pilot with junior students. Stakeholders were largely positive. Findings showed that Clinical Faculty engaged in more role modeling of teaching strategies as Mentors assumed more direct teaching used more clinical reasoning strategies. Students reported increased confidence and competence in clinical care by being integrated into the team and the Mentor's assignment. Two new full time faculty roles in the Health System support education, practice, and research
Gene Network Inference and Biochemical Assessment Delineates GPCR Pathways and CREB Targets in Small Intestinal Neuroendocrine Neoplasia
Small intestinal (SI) neuroendocrine tumors (NET) are increasing in incidence, however little is known about their biology. High throughput techniques such as inference of gene regulatory networks from microarray experiments can objectively define signaling machinery in this disease. Genome-wide co-expression analysis was used to infer gene relevance network in SI-NETs. The network was confirmed to be non-random, scale-free, and highly modular. Functional analysis of gene co-expression modules revealed processes including âNervous system developmentâ, âImmune responseâ, and âCell-cycleâ. Importantly, gene network topology and differential expression analysis identified over-expression of the GPCR signaling regulators, the cAMP synthetase, ADCY2, and the protein kinase A, PRKAR1A. Seven CREB response element (CRE) transcripts associated with proliferation and secretion: BEX1, BICD1, CHGB, CPE, GABRB3, SCG2 and SCG3 as well as ADCY2 and PRKAR1A were measured in an independent SI dataset (nâ=â10 NETs; nâ=â8 normal preparations). All were up-regulated (p<0.035) with the exception of SCG3 which was not differently expressed. Forskolin (a direct cAMP activator, 10â5 M) significantly stimulated transcription of pCREB and 3/7 CREB targets, isoproterenol (a selective Ă-adrenergic receptor agonist and cAMP activator, 10â5 M) stimulated pCREB and 4/7 targets while BIM-53061 (a dopamine D2 and Serotonin [5-HT2] receptor agonist, 10â6 M) stimulated 100% of targets as well as pCREB; CRE transcription correlated with the levels of cAMP accumulation and PKA activity; BIM-53061 stimulated the highest levels of cAMP and PKA (2.8-fold and 2.5-fold vs. 1.8â2-fold for isoproterenol and forskolin). Gene network inference and graph topology analysis in SI NETs suggests that SI NETs express neural GPCRs that activate different CRE targets associated with proliferation and secretion. In vitro studies, in a model NET cell system, confirmed that transcriptional effects are signaled through the cAMP/PKA/pCREB signaling pathway and that a SI NET cell line was most sensitive to a D2 and 5-HT2 receptor agonist BIM-53061.© 2011 Drozdov et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
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