Helicity Amplitudes for Single-Top Production

Single top quark production at hadron colliders allows a direct measurement of the top quark charged current coupling. We present the complete tree-level helicity amplitudes for four processes involving the production and semileptonic decay of a single top quark: W-gluon fusion, flavor excitation, s-channel production and W-associated production. For the first three processes we study the quality of the narrow top width approximation. We also examine momentum and angular distributions of some of the final state particles.Comment: 27 pages, 7 figures, final versio

Current driven switching of magnetic layers

The switching of magnetic layers is studied under the action of a spin current in a ferromagnetic metal/non-magnetic metal/ferromagnetic metal spin valve. We find that the main contribution to the switching comes from the non-equilibrium exchange interaction between the ferromagnetic layers. This interaction defines the magnetic configuration of the layers with minimum energy and establishes the threshold for a critical switching current. Depending on the direction of the critical current, the interaction changes sign and a given magnetic configuration becomes unstable. To model the time dependence of the switching process, we derive a set of coupled Landau-Lifshitz equations for the ferromagnetic layers. Higher order terms in the non-equilibrium exchange coupling allow the system to evolve to its steady-state configuration.Comment: 8 pages, 2 figure. Submitted to Phys. Rev.

Private Insurance, Public Welfare, and Financial Markets: Alpine and Maritime Countries in Comparative-Historical Perspective

Contemporary capitalist societies use different institutions to manage economic risks. While different public welfare state and financial institutions (banks, capital markets) have been studied across coordinated and liberal market economies, this paper adds the private insurance sector to the study of countries’ security arrangements, following up on Michel Albert’s classical distinction between Alpine and Maritime insurance cultures. Building on extensive new insurance data collections (1880–2017) and institutional analysis, this paper corroborates the long-run historical existence of two worlds of private insurance. Maritime countries (USA, GBR, CAN) developed much bigger life and non-life insurance earlier, with no state-associated insurance enterprises and riskier investments steered towards financial markets. Alpine insurance (AUT, DEU, CHE), by contrast, was initially smaller, with strong state involvement, a significant reinsurance tradition and relatively heavy investments in mortgages and property, due to economic and financial backwardness. We argue that the larger and more “Maritime” the insurance sector, the more it made welfare states liberal and securities markets large. Insurance is thus a hidden factor for countries’ varieties of capitalism and world of welfare. The recent convergence on the Maritime model, however, implies that the riskier and risk-individualizing type of private insurance has added to privatization and securitization trends everywhere.Moderne kapitalistische Gesellschaften bedienen sich verschiedener Institutionen, um wirtschaftliche Risiken zu managen. Während wohlfahrtsstaatliche und Finanzinstitutionen (Banken, Kapitalmärkte) in koordinierten und liberalen Marktwirtschaften bereits hinreichend untersucht wurden, wird in diesem Beitrag der private Versicherungssektor in die Untersuchung der Sicherheitsarrangements der Länder einbezogen, aufbauend auf Michel Alberts klassischer Unterscheidung alpiner und maritimer Versicherungskulturen. Mit einer neuen Sammlung von Versicherungsdaten (1880–2017) und einer institutionellen Analyse bestätigt dieses Papier die langfristige historische Existenz zweier Welten privater Versicherung. Die maritimen Länder (USA, GBR, CAN) entwickelten früher viel größere und weniger staatsregulierte Lebens- und Schadensversicherungen mit risikoreicheren Investitionen, die auf die Finanzmärkte gelenkt wurden. Die alpine Versicherung (AUT, DEU, CHE) war dagegen anfangs kleiner, mit einer ausgeprägten staatlichen Beteiligung, einer bedeutenden Rückversicherungstradition und relativ hohen Investitionen in Hypotheken und Immobilien, was auf die wirtschaftliche und finanzielle Rückständigkeit zurückzuführen ist. Wir argumentieren, dass je größer und „maritimer“ der Versicherungssektor war, desto mehr hat er die Wohlfahrtsstaaten liberalisiert und die Wertpapiermärkte vergrößert. Das Versicherungswesen ist somit ein versteckter Faktor für die verschiedenen Kapitalismusformen und Wohlfahrtssysteme der Länder. Die jüngste Konvergenz hin zum maritimen Modell bedeutet jedoch, dass die risikoreichere und risikoindividualisierende Art der privaten Versicherung überall zu Privatisierungs- und Verbriefungstendenzen beigetragen hat.1 Introduction 2 Literature: Between varieties of capitalism and insurance studies 3 Alpine and Maritime insurance cultures Insurance size “Market-based” versus non-market-based portfolios Size of reinsurance Public elements in the insurance market 4 Insurance: A historical life of its own and force to reckon with in welfare and corporate finance Causes of divergence: Alpine and Maritime insurance trajectories Insurance and welfare Insurers and financial systems 5 Conclusion Appendix Reference

A deficit of spatial remapping in constructional apraxia after right-hemisphere stroke

This Article is provided by the Brunel Open Access Publising Fund - Copyright @ 2010 Oxford University PressConstructional apraxia refers to the inability of patients to copy accurately drawings or three-dimensional constructions. It is a common disorder after right parietal stroke, often persisting after initial problems such as visuospatial neglect have resolved. However, there has been very little experimental investigation regarding mechanisms that might contribute to the syndrome. Here, we examined whether a key deficit might be failure to integrate visual information correctly from one fixation to the next. Specifically, we tested whether this deficit might concern remapping of spatial locations across saccades. Right-hemisphere stroke patients with constructional apraxia were compared to patients without constructional problems and neurologically healthy controls. Participants judged whether a pattern shifted position (spatial task) or changed in pattern (non-spatial task) across two saccades, compared to a control condition with an equivalent delay but without intervening eye movements. Patients with constructional apraxia were found to be significantly impaired in position judgements with intervening saccades, particularly when the first saccade of the sequence was to the right. The importance of these remapping deficits in constructional apraxia was confirmed through a highly significant correlation between saccade task performance and constructional impairment on standard neuropsychological tasks. A second study revealed that even single saccades to the right can impair constructional apraxia patients’ perception of location shifts. These data are consistent with the view that rightward eye movements result in loss of remembered spatial information from previous fixations, presumably due to constructional apraxia patients’ damage to the right-hemisphere regions involved in remapping locations across saccades. These findings provide the first evidence for a deficit in remapping visual information across saccades underlying right-hemisphere constructional apraxia.European Commission Marie Curie Intra-European Fellowship (011457 to C.R.) and a Wellcome Trust Senior Fellowship (to M.H.)

How Do You Build a "Culture of Health"? A Critical Analysis of Challenges and Opportunities from Medical Anthropology.

The Robert Wood Johnson Foundation's Culture of Health Action Framework aims to "make health a shared value" and improve population health equity through widespread culture change. The authors draw upon their expertise as anthropologists to identify 3 challenges that they believe must be addressed in order to effectively achieve the health equity and population health improvement goals of the Culture of Health initiative: clarifying and demystifying the concept of "culture," contextualizing "community" within networks of power and inequality, and confronting the crises of trust and solidarity in the contemporary United States. The authors suggest that those who seek to build a "Culture of Health" refine their understanding of how "culture" is experienced, advocate for policies and practices that break down unhealthy consolidations of power, and innovate solutions to building consensus in a divided nation

SRA: Fast Removal of General Multipath for ToF Sensors

A major issue with Time of Flight sensors is the presence of multipath interference. We present Sparse Reflections Analysis (SRA), an algorithm for removing this interference which has two main advantages. First, it allows for very general forms of multipath, including interference with three or more paths, diffuse multipath resulting from Lambertian surfaces, and combinations thereof. SRA removes this general multipath with robust techniques based on $L_1$ optimization. Second, due to a novel dimension reduction, we are able to produce a very fast version of SRA, which is able to run at frame rate. Experimental results on both synthetic data with ground truth, as well as real images of challenging scenes, validate the approach

Tackling 3D ToF Artifacts Through Learning and the FLAT Dataset

Scene motion, multiple reflections, and sensor noise introduce artifacts in the depth reconstruction performed by time-of-flight cameras. We propose a two-stage, deep-learning approach to address all of these sources of artifacts simultaneously. We also introduce FLAT, a synthetic dataset of 2000 ToF measurements that capture all of these nonidealities, and allows to simulate different camera hardware. Using the Kinect 2 camera as a baseline, we show improved reconstruction errors over state-of-the-art methods, on both simulated and real data.Comment: ECCV 201