Application of the Iterated Weighted Least-Squares Fit to counting experiments

Least-squares fits are an important tool in many data analysis applications. In this paper, we review theoretical results, which are relevant for their application to data from counting experiments. Using a simple example, we illustrate the well known fact that commonly used variants of the least-squares fit applied to Poisson-distributed data produce biased estimates. The bias can be overcome with an iterated weighted least-squares method, which produces results identical to the maximum-likelihood method. For linear models, the iterated weighted least-squares method converges faster than the equivalent maximum-likelihood method, and does not require problem-specific starting values, which may be a practical advantage. The equivalence of both methods also holds for binomially distributed data. We further show that the unbinned maximum-likelihood method can be derived as a limiting case of the iterated least-squares fit when the bin width goes to zero, which demonstrates a deep connection between the two methods.Comment: Accepted by NIM

Perspektiven der Europäischen Sicherheits- und Verteidigungspolitik

Mit der Entscheidung, die Aufgaben der Krisenbewältigung in die eigene Hand zu nehmen, erschließt die EU ein ganz neues Feld der Zusammenarbeit und hat dadurch bereits jetzt die Machtkonstellation in Europa und gegenüber den transatlantischen Partnern verändert. Doch noch sind viele Fragen offen, die Zielsetzungen teilweise gar widersprüchlich: Wie könnte eine mögliche Arbeitsteilung zwischen NATO und ESVP aussehen? Sollte sich die EU auf Krisenbewältigung beschränken oder auch die Verantwortung für die kollektive Verteidigung ihrer Außengrenzen übernehmen und auf welche Bedrohungsszenarien muss sich Europa in diesem Zusammenhang einstellen? Wie sollen die Anteile von zivilen und militärischen Instrumenten gewichtet sein? Wie lässt sich das Spannungsverhältnis zwischen regionalen und globalen Prinzipien nicht zuletzt gegenüber den Vereinten Nationen, wie das zwischen Legitimität und Effektivität innerhalb der Gemeinschaft auflösen? Diesen Fragen und den sich daraus ergebenden Interessenkonflikten innerhalb Europas und des transatlantischen Bündnisses geht der Autor nach, zeigt Entwicklungspotentiale auf und plädiert für eine angemessene, aber bescheidene Rolle der Europäischen Sicherheits- und Verteidigungspolitik: So sollte die EU nicht den Anspruch erheben, Weltmacht zu werden

The Incompleteness of the Economy and Business: A Forceful Reminder

Many different but related arguments developed in the Caritas in Veritate converge on one central, yet not clearly stated, conclusion or thesis: economic and business activities are ‘incomplete'. This article will explore the above-mentioned ‘incompleteness' thesis or argument from three different perspectives: the role, the practice and the purpose of economic and business activities in contemporary societies. In doing so, the paper will heavily draw on questions and, still not fully learned, lessons derived from the present financial and economic crisis. Caritas in Veritate provides an appealing moral framework in which many of these lessons take a deeper sense and a more comprehensive meaning. The notion of ‘incompleteness' is applied here to economic and business theory and practice in the sense derived from Gödel's theorems. They state in terms of logical and mathematical demonstrations that no system of axiomatic statements can provide a proof of its own consistency. Such a proof requires the use of statements belonging to another (higher) level system. In the case of economics or business theory and practice these ‘higher level' statements are value judgments. By stressing the importance of ethics and moral philosophy for daily life, Caritas in Veritate strongly reminds us that neither economy nor business are self-sufficient either in organisational and social, practical or moral term

Bureaucratic Power Europe

Die Forschung stimmt in der Beobachtung überein, dass sich der globale Akteur EU im Gegensatz zu ähnlich großen Staaten durch ein ausgeprägt regelorientiertes Verhalten, eine Vorliebe für Multilateralismus und für Kompromisslösungen sowie eine starke Abneigung gegen Erzwingungsmacht und den Einsatz militärischer Instrumente auszeichnet. Sie streitet über die Gründe für diese auffällige Verhalten. Dieses Working Paper kommt zu Ergebnis, dass das äußere Verhalten der EU ihren inneren institutionellen Strukturen geschuldet ist. Bei Entscheidungen in der Außen- und Sicherheitspolitik herrscht das Konsensprinzip. Um die daraus entstehenden Handlungsdefizite abzuschwächen, hat die EU seit Maastricht 1992 in immer stärkerem Maße Kompetenzen an internationale Bürokratien wie den Europäischen Auswärtigen Dienst delegiert. Dies hat Konsequenzen. Bürokratien handeln regelorientiert und prägen so das Verhalten der EU als globaler Akteur. Anders als im Staat steht der Bürokratie in der EU nicht die Institution des politischen Entscheiders gegenüber, sondern ein Kollektivorgan: der Europäische Rat oder der Ministerrat. Und Kollektivorgane handeln in einem ähnlichen Modus wie die Bürokratie, nämlich pfadabhängig und regelorientiert. Eine Fallstudie zur Ukrainepolitik der EU illustriert den Charakter der EU als bürokratische Macht.Ever since the academic community accepted the notion of the EU as a global actor, it has speculated on the ‘nature of the beast'. Scholars concur that the EU as a global actor is characterised by a penchant for multilateralism and rule-based policy approaches and have devised conceptual characterisations such as civilian, ethical and normative power to capture this behaviour. This paper presents an alternative explanation of the EU's foreign policy behaviour that is grounded in liberal theory and refers to the interplay between the influence of international bureaucracies and intergovernmental decision-making. A case study on EU-Ukraine relations in the context of the European Neighbourhood Policy illustrates the theoretical argument

Procedural justice and global order: explaining African reaction to the application of global protection norms

Persistent tensions between the international norm of state sovereignty and emerging human rights norms including the responsibility to protect and the protection of civilians during international peacekeeping raise the question of when and under what circumstances local and regional actors are more likely to respect global norms. These tensions are particularly stark in Africa. On the one hand, African states and regional organization were among the first proponents of liberal protection norms in the non-Western world. On the other hand, many African leaders view state sovereignty as indispensable. Building on established empirical justice research in neighboring fields, this paper makes an important contribution to the literature by demonstrating that African states are more likely to accept interventionist human rights norms when standards of procedural justice have been observed. The article demonstrates the relevance of procedural justice by examining the puzzle of divergent African reactions to two similar instances of regime change in Libya and the Ivory Coast that have been enforced by extra-continental actors in the name of global protection norms

Potential for measuring the longitudinal and lateral profile of muons in TeV air showers with IACTs

Muons are copiously produced within hadronic extensive air showers (EAS) occurring in the Earth's atmosphere, and are used by particle air shower detectors as a means of identifying the primary cosmic ray which initiated the EAS. Imaging Atmospheric Cherenkov Telescopes (IACTs), designed for the detection of gamma-ray initiated EAS for the purposes of Very High Energy (VHE) gamma-ray astronomy, are subject to a considerable background signal due to hadronic EAS. Although hadronic EAS are typically rejected for gamma-ray analysis purposes, single muons produced within such showers generate clearly identifiable signals in IACTs and muon images are routinely retained and used for calibration purposes. For IACT arrays operating with a stereoscopic trigger, when a muon triggers one telescope, other telescopes in IACT arrays usually detect the associated hadronic EAS. We demonstrate for the first time the potential of IACT arrays for competitive measurements of the muon content of air showers, their lateral distribution and longitudinal profile of production slant heights in the TeV energy range. Such information can provide useful input to hadronic interaction models.Comment: 15 pages, 11 figures, 2 tables, accepted for publication in Astroparticle Physic

A likelihood method to cross-calibrate air-shower detectors

We present a detailed statistical treatment of the energy calibration of hybrid air-shower detectors, which combine a surface detector array and a fluorescence detector, to obtain an unbiased estimate of the calibration curve. The special features of calibration data from air showers prevent unbiased results, if a standard least-squares fit is applied to the problem. We develop a general maximum-likelihood approach, based on the detailed statistical model, to solve the problem. Our approach was developed for the Pierre Auger Observatory, but the applied principles are general and can be transferred to other air-shower experiments, even to the cross-calibration of other observables. Since our general likelihood function is expensive to compute, we derive two approximations with significantly smaller computational cost. In the recent years both have been used to calibrate data of the Pierre Auger Observatory. We demonstrate that these approximations introduce negligible bias when they are applied to simulated toy experiments, which mimic realistic experimental conditions.Comment: 10 pages, 7 figure

Las grandes empresas, las firmas focales y el valor añadido global

El artículo comienza presentando una evidencia empírica de la actuación económica de las empresas más importantes que cotizan en bolsa, llamadas en este artículo VLE (very large entreprises). Esta evidencia sugiere que estas empresas contribuyen en gran proporción al crecimiento macroeconómico. En la segunda parte del artículo se plantea, entre las muchas causas potenciales que pueden explicar este hecho, una hipótesis basada en el papel que pueden jugar las VLE dentro de las firmas focales, dando lugar a Cadenas de Valor Globales. La peculiaridad de una firma focal radica en que organiza el trabajo de otras empresas, involucradas todas ellas en eslabones de producción y distribución de la misma cadena. En consecuencia, la actuación económica de las compañías más importantes podría capturar una porción de esfuerzo y hacer realidad su actuación gracias a sus pequeños colaboradores, ya sean proveedores o distribuidores._______________________The paper starts by presenting the empirical evidence on to the economic performance of largest among the stock exchange listed firms, named in this paper VLE (very large enterprises). This evidence suggests that these very large firms contribute a significant proportion of macro-economic growth. Among many potential explanation of this situation, one hypothesis is explored in the second part of the paper, namely the role of “focal firm” that many of the VLE may play within existing and emerging Global Value Chains. The peculiarity of a “focal firm” is that it organises the work of other enterprises involved both in the production and distribution portions of the chain. In consequence, the economic performance of the largest may well capture a portion of effort and performance realized by its smaller partners, be it suppliers or distributors