855 research outputs found
Luminescence of water or ice as a new detection method for magnetic monopoles
No full textCosmic ray detectors use air as a radiator for luminescence. In water and ice, Cherenkov light is the dominant light producing mechanism when the particle’s velocity exceeds the Cherenkov threshold, approximately three quarters of the speed of light in vacuum.
Luminescence is produced by highly ionizing particles passing through matter due to the electronic excitation of the surrounding molecules. The observables of luminescence, such as the wavelength spectrum and decay times, are highly dependent on the properties of the medium, in particular, temperature and purity. The results for the light yield of luminescence of previous measurements vary by two orders of magnitude.
It will be shown that even for the lowest measured light yield, luminescence is an important signature of highly ionizing particles below the Cherenkov threshold. These could be magnetic monopoles or other massive and highly ionizing exotic particles. With the highest observed efficiencies, luminescence may even contribute significantly to the light output of standard model particles such as the PeV IceCube neutrinos.
We present analysis techniques to use luminescence in neutrino telescopes and discuss experimental setups to measure the light yield of luminescence for the particular conditions in neutrino detectors
Jesus Christ and Dionysus
No full textAbstract
The cento Christus patiens takes about one-third of its c.2,600 iambic trimeters from tragedies by Euripides, telling in dramatic form the story of Christ’s Passion, death, and resurrection. This chapter argues that for metrical and lexical reasons the cento’s much disputed authorship has to be decided against Gregory of Nazianzus and in favour of a twelfth-century Byzantine author. An analysis of the adaptation of the Euripidean verses demonstrates the cento not to be viewed as mere learned play. The aim of this centonic transformation is to reveal the true, hidden sense of the famous pagan original, by employing various different modes of transferral and alteration, which confirms the findings in Chapter 4. The chapter’s groundbreaking contribution consists in elaborating the cento’s ultimate and highly original goal to contrast the vindictive pagan destroyer Dionysus with the merciful redeemer Jesus Christ in this Christian anti-tragedy with its new and different world-view.</jats:p
Neural basis for priming of pop-out during visual search revealed with fMRI
No full textMalikovic and Nakayama first showed that visual search efficiency can be influenced by priming effects. Even "pop-out" targets (defined by unique color) are judged quicker if they appear at the same location and/or in the same color as on the preceding trial, in an unpredictable sequence. Here, we studied the potential neural correlates of such priming in human visual search using functional magnetic resonance imaging (fMRI). We found that repeating either the location or the color of a singleton target led to repetition suppression of blood oxygen level-dependent (BOLD) activity in brain regions traditionally linked with attentional control, including bilateral intraparietal sulci. This indicates that the attention system of the human brain can be "primed," in apparent analogy to repetition-suppression effects on activity in other neural systems. For repetition of target color but not location, we also found repetition suppression in inferior temporal areas that may be associated with color processing, whereas repetition of target location led to greater reduction of activation in contralateral inferior parietal and frontal areas, relative to color repetition. The frontal eye fields were also implicated, notably when both target properties (color and location) were repeated together, which also led to further BOLD decreases in anterior fusiform cortex not seen when either property was repeated alone. These findings reveal the neural correlates for priming of pop-out search, including commonalities, differences, and interactions between location and color repetition. fMRI repetition-suppression effects may arise in components of the attention network because these settle into a stable 1. attractor state" more readily when the same target property is repeated than when a different attentional state is required
Decision by sampling
No full textWe present a theory of decision by sampling (DbS) in which, in contrast with traditional models, there are no underlying psychoeconomic scales. Instead, we assume that an attribute’s subjective value is constructed from a series of binary, ordinal comparisons to a sample of attribute values drawn from memory and is its rank within the sample. We assume that the sample reflects both the immediate distribution of attribute values from the current decision’s context and also the background, real-world distribution of attribute values. DbS accounts for concave utility functions; losses looming larger than gains; hyperbolic temporal discounting; and the overestimation of small probabilities and the underestimation of large probabilities
Ablösung des General Hedge Accountings nach IAS 39 durch IFRS 9: Analyse und Beurteilung von Entscheidungsnützlichkeit im Fokus der Risikomanagementannäherung und Komplexitätsreduktion : Implikationen für Standardsetzung und Bilanzierungspraxis
No full textZinssatzänderungen, Wechselkursschwankungen oder Veränderungen der Rohstoffpreise spiegeln die Dynamik der volatiler werdenden nationalen wie internationalen Finanz-, Kapital- und Gütermärkte wider. Aufgrund der zunehmenden Bedeutung von Marktpreisrisiken rücken Art und Umfang der Risikomanagementaktivitäten in den Fokus, wobei der internen Steuerungsebene von Markpreisrisiken eine besondere Stellung beizumessen ist. Während Unternehmen über zunehmend differenziertere Risikomanagementsysteme verfügen, konnten die Regelungen zur Bilanzierung von Sicherungsbeziehungen den vielfältigen Anforderungen seit jeher nur bedingt gerecht werden. Nicht zuletzt aufgrund der Diversität und Dynamik des finanzwirtschaftlichen Risikomanagements zählt die Abbildung risikoökonomischer Sicherungsstrategien im Zuge des Hedge Accountings zu den zentralen Herausforderungen der IFRS-Rechnungslegung. Gleichwohl bereits IAS 39 umfangreiche Vorschriften für eine zusammenführende Bilanzierung der risikobegründenden und -steuernden Transaktion bereitstellt, stellen die bisherigen Regelungen zum Hedge Accounting Anwender und Adressaten infolge konzeptioneller Limitationen, kasuistischer Voraussetzungen und überdurchschnittlicher Regelbasiertheit vor immense Herausforderungen. Nicht nur angesichts der hohen Komplexität, sondern insbesondere auch aufgrund der mangelhaften Abbildungsmöglichkeiten des internen Risikomanagements und oftmals schlichtweg zu konstatierenden Divergenzen zwischen bilanzieller und interner Sicherungsebene, ist das Hedge Accounting-Regelwerk seit Einführung von IAS 39 fortwährenden Kontroversen ausgesetzt, die mithin Zweifel an der Verwertbarkeit entsprechender Informationen im Hinblick einer entscheidungsnützlichen Prognosegrundlage haben entstehen lassen. Mit Phase drei des IAS 39 Replacement-Projekts wurden die bisherigen Vorschriften umfassend überarbeitet und durch IFRS 9 abgelöst. Mit den Neuregelungen zum General Hedge Accounting bezweckt der Standardsetter eine Erhöhung der Entscheidungsnützlichkeit, wobei die projektspezifische Zielsetzung von IFRS 9 zugleich eine weitreichende Annäherung der Bilanzierung von Sicherungsbeziehungen an das interne Risikomanagement Sinne des Management Approachs vorsieht und darüber hinaus explizit eine Komplexitätsreduktion des Regelwerks anstrebt. Die mit der Ablösung von IAS 39 einhergehenden Zielsetzungen werden durch das vorliegende Werk aufgegriffen. Im Rahmen einer umfassenden Analyse und Beurteilung des Hedge Accountings nach IAS 39 und IFRS 9 trifft der Autor dabei sowohl Aussagen zur Entscheidungsnützlichkeit der Neuregelungen als auch Schlussfolgerungen in Bezug auf die beabsichtigte Risikomanagementannäherung und Komplexitätsreduktion. Im Ergebnis werden Handlungsempfehlungen und Lösungsansätze für die Standardsetzung und Bilanzierungspraxis erarbeitet, die sowohl Implikationen in Bezug auf die Entscheidungsnützlichkeit des Hedge Accountings nach IFRS 9 umfassen als auch Potenziale der Risikomanagementannäherung und Komplexitätsreduktion aufzeigen.Changes in interest rates, exchange rates or commodity prices reflect the dynamics of increasingly volatile national and international financial, capital and goods markets. Due to the increasing importance of market price risks, the type and scope of risk management activities are coming into focus, with the internal management level of market price risks being accorded a special position. While companies have increasingly sophisticated risk management systems, the regulations governing hedge accounting have always been able to meet the diverse requirements only to a limited extent. Not least because of the diversity and dynamics of financial risk management, the presentation of hedging strategies within the scope of hedge accounting is one of the central challenges of IFRS accounting. Although IAS 39 already provides comprehensive rules for the combined accounting of risk-creating and risk-controlling transactions, the existing rules on hedge accounting present challenges because of conceptual limitations, casuistic requirements and rule-based nature. Since the introduction of IAS 39, the hedge accounting framework has been subject to ongoing controversy, not only due to the high level of complexity but also due to the inadequate possibilities for mapping internal risk management and the divergences between the balance sheet and internal hedging levels, which are often simply to be stated. With phase three of the IAS 39 Replacement Project, the previous regulations were comprehensively revised and replaced by IFRS 9. With the new regulations on general hedge accounting, the IASB aims to increase the usefulness for decision-making, whereby the project-specific objective of IFRS 9 also provides for a far-reaching convergence of hedge accounting with internal risk management in the sense of the management approach and, in addition, explicitly aims to reduce the complexity of the regulations. The objectives associated with the replacement of IAS 39 are taken up by the present work. Within the framework of a comprehensive analysis and assessment of hedge accounting according to IAS 39 and IFRS 9, the author makes statements on the usefulness of the new regulations for decision-making as well as conclusions regarding to the intended risk management approach and reduction of complexity. As a result, recommendations for action and solutions for standard setting and accounting practice are developed, which include both implications regarding the usefulness of hedge accounting according to IFRS 9 for decision-making and show potentials for risk management approximation and complexity reduction
The role of the pre-supplementary motor area in the control of action
No full textAlthough regions within the medial frontal cortex are known to be active during voluntary movements their precise role remains unclear. Here we combine functional imaging localisation with psychophysics to demonstrate a strikingly selective contralesional impairment in the ability to inhibit ongoing movement plans in a patient with a rare lesion involving the right pre-supplementary motor area (pre-SMA), but sparing the supplementary motor area (SMA). We find no corresponding delay in simple reaction times, and show that the inhibitory deficit is sensitive to the presence of competition between responses. The findings demonstrate that the pre-SMA plays a critical role in exerting control over voluntary actions in situations of response conflict. We discuss these findings in the context of a unified framework of pre-SMA function, and explore the degree to which extant data on this region can be explained by this function alone
Titularidade da rede rodoviária do distrito do Porto: dúvidas e desafios
No full textDissertação apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Engenharia CivilNo seguimento das alterações verificadas a nível nacional referentes às responsabilidades da titularidade das redes viárias, não houve um acompanhamento adequado por parte das entidades oficiais à nova realidade.
A sinalização atual para as vias rodoviárias deveria acompanhar a realidade factual, o que, muitas vezes, não acontece.
A partir da análise dos dados recolhidos, da experiência obtida com os muitos quilómetros percorridos e da verificação “in situ”, além dos muitos contactos pessoais com utentes, entidades e empresas, conseguiu-se compreender a complexidade deste tema.
Inesperadamente, concluiu-se que a grande maioria dos interessados, entre os quais surpreendentemente entidades oficiais, desconhecem por completo a autoridade responsável por certos troços rodoviários.
Tendo em conta a impossibilidade de abranger toda a rede rodoviária nacional continental, escolheu-se por motivos óbvios, exercendo a autora funções na Gestão Regional do Porto da EP - Estradas de Portugal, S.A., a rede viária do Distrito do Porto, que se analisou detalhadamente.
Assim sendo, este trabalho propõe várias sugestões para resolver este problema, preconizando entre outros a aplicação de sinais adequados e de aplicabilidade específica à informação do utilizador referente à titularidade da rede rodoviária.Subsequent to changes at national level in Portugal regarding responsibility related to ownership of the road network, official authorities failed to ensure adequate follow-up of the new situation.
Current road signage should reflect the factual situation and this is frequently not the case.
An analysis of the data collected, experience gained over many kilometers travelled and in situ observation, as well as personal contacts with users, entities and companies, provided an understanding of the complexity of this issue.
Unexpectedly, it was concluded that most of the stakeholders, including official authorities, are completely unaware of which authority is responsible for certain sections of road.
As it was not possible to study the whole national road network in mainland Portugal, the obvious choice was to study the road network in the district of Porto, given that the author works for Porto Regional Management of EP - Estradas de Portugal, S.A., and this network was analyzed in detail.
This paper therefore puts forward various suggestions on how to resolve this problem, including the use of appropriate signage and the provision of specific information to users on ownership related to the road network
Correction: Meta-Analysis of the Relationship between Multiple Sclerosis and Migraine.
No full textThis 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.PMCID: PMC3613438PMCID: PMC3613438PMCID: PMC3613438PMCID: PMC3613438[This corrects the article on p. e45295 in vol. 7.]
Decision by sampling
No full textWe present a theory of decision by sampling (DbS) in which, in contrast with traditional
models, there are no underlying psychoeconomic scales. Instead, we assume that an
attribute's subjective value is constructed from a series of binary, ordinal comparisons to a
sample of attribute values drawn from memory and is its rank within the sample. We assume
that the sample reflects both the immediate distribution of attribute values from the current
decision's context and also the background, real-world distribution of attribute values. DbS
accounts for concave utility functions; losses looming larger than gains; hyperbolic temporal
discounting; and the overestimation of small probabilities and the underestimation of large
probabilities
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