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

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

Electromagnetic vertex function of the pion at T > 0

The matrix element of the electromagnetic current between pion states is calculated in quenched lattice QCD at a temperature of $T = 0.93 T_c$. The nonperturbatively improved Sheikholeslami-Wohlert action is used together with the corresponding ${\cal O}(a)$ improved vector current. The electromagnetic vertex function is extracted for pion masses down to $360 {\rm MeV}$ and momentum transfers $Q^2 \le 2.7 {\rm GeV}^2$.Comment: 17 pages, 8 figure

Palliative care consultation services in hospitals in the Netherlands: The design of the COMPASS study

Background: Patients with an advanced incurable disease are often hospitalised for some time during the last phase of life. Care in hospitals is generally focussed at curing disease and prolonging life and may therefore not in all cases adequately address the needs of such patients. We present the COMPASS study, a study on the effects and costs of consultation teams for palliative care in hospitals. This observational study aims to investigate the use, effects and costs of PCT consultation services for hospitalized patients with incurable cancer in the Netherlands. Methods/design: The study consists of 3 parts: 1. A questionnaire, interviews and a focus group discussion to investigate the characteristics of PCT consultation in 12 hospitals. PCTs will register their activities to calculate the costs of PCT consultation. 2. Cancer patients for whom the attending physician would not be surprised that they would die within 12 month will be included in a medical file search in three hospitals. Medical records will be investigated to compare care, treatment and hospital costs between patients with and patients without PCT consultation. 3. In the other nine hospitals, we will perform a longitudinal study, and compare quality of life between 100 patients for whom a PCT was consulted with 200 patients without PCT consultation. Propensity score matching will be used to adjust for differences between both patient groups. Patients will be followed for three months after inclusion. Quality of life will be assessed with the Palliative Outcome Scale, the EuroQol-5d and the EORTC-QLQ-C15 PAL. Satisfaction with care in the hospital is measured with the IN-PATSAT32. The cost impact of PCT consultation will also be explored. Discussion: This is the first multicenter study on PCT consultation in the Netherlands. The study will give valuable insight in the process, effects and costs of PCT consultation in hospitals. It is anticipated that PCT consultation has a positive effect on patients' quality of life and satisfaction with care and will lead to less hospital care costs

Positive Feedbacks in Seagrass Ecosystems – Evidence from Large-Scale Empirical Data

Positive feedbacks cause a nonlinear response of ecosystems to environmental change and may even cause bistability. Even though the importance of feedback mechanisms has been demonstrated for many types of ecosystems, their identification and quantification is still difficult. Here, we investigated whether positive feedbacks between seagrasses and light conditions are likely in seagrass ecosystems dominated by the temperate seagrass Zostera marina. We applied a combination of multiple linear regression and structural equation modeling (SEM) on a dataset containing 83 sites scattered across Western Europe. Results confirmed that a positive feedback between sediment conditions, light conditions and seagrass density is likely to exist in seagrass ecosystems. This feedback indicated that seagrasses are able to trap and stabilize suspended sediments, which in turn improves water clarity and seagrass growth conditions. Furthermore, our analyses demonstrated that effects of eutrophication on light conditions, as indicated by surface water total nitrogen, were on average at least as important as sediment conditions. This suggests that in general, eutrophication might be the most important factor controlling seagrasses in sheltered estuaries, while the seagrass-sediment-light feedback is a dominant mechanism in more exposed areas. Our study demonstrates the potentials of SEM to identify and quantify positive feedbacks mechanisms for ecosystems and other complex systems

Animation in relational information visualization

In order to be able to navigate in the world without memorizing each detail, the human brain builds a mental map of its environment. The mental map is a distorted and abstracted representation of the real environment. Unimportant areas tend to be collapsed to a single entity while important landmarks are overemphasized. When working with visualizations of data we build a mental map of the data which is closely linked to the particular visualization. If the visualization changes significantly due to changes in the data or the way it is presented we loose the mental map and have to rebuild it from scratch. The purpose of the research underlying this thesis was to investigate and devise methods to create smooth transformations between visualizations of relational data which help users in maintaining or quickly updating their mental map

Positive Feedbacks in Seagrass Ecosystems – Evidence from Large-Scale Empirical Data

Positive feedbacks cause a nonlinear response of ecosystems to environmental change and may even cause bistability. Even though the importance of feedback mechanisms has been demonstrated for many types of ecosystems, their identification and quantification is still difficult. Here, we investigated whether positive feedbacks between seagrasses and light conditions are likely in seagrass ecosystems dominated by the temperate seagrass Zostera marina. We applied a combination of multiple linear regression and structural equation modeling (SEM) on a dataset containing 83 sites scattered across Western Europe. Results confirmed that a positive feedback between sediment conditions, light conditions and seagrass density is likely to exist in seagrass ecosystems. This feedback indicated that seagrasses are able to trap and stabilize suspended sediments, which in turn improves water clarity and seagrass growth conditions. Furthermore, our analyses demonstrated that effects of eutrophication on light conditions, as indicated by surface water total nitrogen, were on average at least as important as sediment conditions. This suggests that in general, eutrophication might be the most important factor controlling seagrasses in sheltered estuaries, while the seagrass-sediment-light feedback is a dominant mechanism in more exposed areas. Our study demonstrates the potentials of SEM to identify and quantify positive feedbacks mechanisms for ecosystems and other complex systems

The perspectives of clinical staff and bereaved informal care-givers on the use of continuous sedation until death for cancer patients: The study protocol of the UNBIASED study

Background: A significant minority of dying people experience refractory symptoms or extreme distress unresponsive to conventional therapies. In such circumstances, sedation may be used to decrease or remove consciousness until death occurs. This practice is described in a variety of ways, including: ‘palliative sedation’, ‘terminal sedation’, ‘continuous deep sedation until death’, ‘proportionate sedation’ or ‘palliative sedation to unconsciousness’. Surveys show large unexplained variation in incidence of sedation at the end of life across countries and care settings and there are ethical concerns about the use, intentions, risks and significance of the practice in palliative care. There are also questions about how to explain international variation in the use of the practice. This protocol relates to the UNBIASED study (UK Netherlands Belgium International Sedation Study), which comprises three linked studies with separate funding sources in the UK, Belgium and the Netherlands. The aims of the study are to explore decision-making surrounding the application of continuous sedation until death in contemporary clinical practice, and to understand the experiences of clinical staff and decedents’ informal caregivers of the use of continuous sedation until death and their perceptions of its contribution to the dying process. The UNBIASED study is part of the European Association for Palliative Care Research Network. Methods/Design: To realize the study aims, a two-phase study has been designed. The study settings include: the domestic home, hospital and expert palliative care sites. Phase 1 consists of: a) focus groups with health care staff and bereaved informal care-givers; and b) a preliminary case notes review to study the range of sedation therapy provided at the end of life to cancer patients who died within a 12 week period. Phase 2 employs qualitative methods to develop 30 patient-centred case studies in each country. These involve interviews with staff and informal care-givers closely involved in the care of cancer patients who received continuous sedation until death. Discussion: To our knowledge, this is one of the few studies which seek to take a qualitative perspective on clinical decision making surrounding the use of continuous sedation until death and the only one which includes the perspectives of nurses, physicians, as well as bereaved informal care-givers. It has several potential strengths, weaknesses, opportunities and threats associated with the specific design of the study, as well as with the sensitive nature of the topic and the different frameworks for ethical review in the participating countries