Picosecond pulse amplification up to a peak power of 42 W by a quantum-dot tapered optical amplifier and a mode-locked laser emitting at 1.26 μm

We experimentally study the generation and amplification of stable picosecond-short optical pulses by a master oscillator power-amplifier configuration consisting of a monolithic quantum-dot-based gain-guided tapered laser and amplifier emitting at 1.26 μm without pulse compression, external cavity, gain-or Q-switched operation. We report a peak power of 42 W and a figure-of-merit for second-order nonlinear imaging of 38.5 W2 at a repetition rate of 16 GHz and an associated pulse width of 1.37 ps.

Optical properties of some surfaces for solar energy application

The preThe present work is a study of the optical properties of some surfaces, in order to determine their applications in solar energy utilisation. An attempt has been made to investigate and measure the optical properties of two systems of surface moderately selective surfaces like thermally grown oxide of titanium, titanium oxide en aluminium and thermally grown oxides of stainless steel; and, selective surfaces of five different coloured stainless at (INCO surfaces) and of black nickel foil. A calorimetric instrument based on the steady state method for measuring directly the total emittance has been designed. Chapter 1 is an introductory survey of selective surface. It also includes a brief review of various preparation techniques in use since 1955. Chapter 2 investigates the theory of selective surfaces, defining their optical properties and their figures of merit. It also outlines the method of computing the optical properties (i.e. absorptance, a, and emittance, a) which have been adopted for the present work. Chapter 3 describes the measuring technique and the modes of operation of the equipment used in the experimental work carried out. Chapter 4 gives the results of the experimental work to measure the optical properties, the life testing and chemical composition of the surfaces under study. Chapter 5 deals with the experimentation leading to the design of a calorimetric instrument for measuring the total emmitance directly. Chapter 6 presents concluding remarks about the outcome of the present work and some suggestions for further work. sent work is a study of the optical properties of some surfaces, in order to determine their applications in solar energy utilisation. An attempt has been made to investigate and measure the optical properties of two systems of surface moderately selective surfaces like thermally grown oxide of titanium, titanium oxide en aluminium and thermally grown oxides of stainless steel; and, selective surfaces of five different coloured stainless at (INCO surfaces) and of black nickel foil. A calorimetric instrument based on the steady state method for measuring directly the total emittance has been designed. Chapter 1 is an introductory survey of selective surface. It also includes a brief review of various preparation techniques in use since 1955. Chapter 2 investigates the theory of selective surfaces, defining their optical properties and their figures of merit. It also outlines the method of computing the optical properties (i.e. absorptance, a, and emittance, a) which have been adopted for the present work. Chapter 3 describes the measuring technique and the modes of operation of the equipment used in the experimental work carried out. Chapter 4 gives the results of the experimental work to measure the optical properties, the life testing and chemical composition of the surfaces under study. Chapter 5 deals with the experimentation leading to the design of a calorimetric instrument for measuring the total emmitance directly. Chapter 6 presents concluding remarks about the outcome of the present work and some suggestions for further work.

The development of constrained source localisation algorithms for human brain imaging

This work sets out to evaluate the potential benefits and pit-falls in using a priori information to help solve the Magnetoencephalographic (MEG) inverse problem. In chapter one the forward problem in MEG is introduced, together with a scheme that demonstrates how a priori information can be incorporated into the inverse problem. Chapter two contains a literature review of techniques currently used to solve the inverse problem. Emphasis is put on the kind of a priori information that is used by each of these techniques and the ease with which additional constraints can be applied. The formalism of the FOCUSS algorithm is shown to allow for the incorporation of a priori information in an insightful and straightforward manner. In chapter three it is described how anatomical constraints, in the form of a realistically shaped source space, can be extracted from a subject’s Magnetic Resonance Image (MRI). The use of such constraints relies on accurate co-registration of the MEG and MRI co-ordinate systems. Variations of the two main co-registration approaches, based on fiducial markers or on surface matching, are described and the accuracy and robustness of a surface matching algorithm is evaluated. Figures of merit introduced in chapter four are shown to given insight into the limitations of a typical measurement set-up and potential value of a priori information. It is shown in chapter five that constrained dipole fitting and FOCUSS outperform unconstrained dipole fitting when data with low SNR is used. However, the effect of errors in the constraints can reduce this advantage. Finally, it is demonstrated in chapter six that the results of different localisation techniques give corroborative evidence about the location and activation sequence of the human visual cortical areas underlying the first 125ms of the visual magnetic evoked response recorded with a whole head neuromagnetometer.

Cardiocentric neurophysiology:the persistence of a delusion

Aristotle is well known to have taught that the brain was a mere coolant apparatus for overheated blood and to have located the hegemonikon in the heart. This teaching was hotly disputed by his immediate successors in the Alexandrian Museum, who showed that the brain played the central role in psychophysiology. This was accepted and developed by the last great biomedical figure of classical antiquity - Claudius Galen. However, Aristotle's cardiocentric theory did not entirely disappear and this article traces its influence through the Arabic physicians of the Islamic ascendancy, into the European Middle Ages where Albertus Magnus' attempt to reconcile cardiocentric and cerebrocentric physiology was particularly influential. It shows how cardiocentricity was sufficiently accepted to attract the attention of, and require refutation by, many of the great names of the Renaissance, including Vesalius, Fernel, and Descartes, and was still taken seriously by luminaries such as William Harvey in the mid-seventeenth century. The article, in rehearsing this history, shows the difficulty of separating the first-person perspective of introspective psychology and the third-person perspective of natural science. It also outlines an interesting case of conflict between philosophy and physiology. © 2013 Copyright Taylor & Francis Group, LLC.

Polarization dynamics of bound state solitons in a carbon nanotubes mode locked erbium doped fiber laser

Optical solitons are important in the modern photonics. Passively mode locked erbium doped fiber lasers provide a neat platform to study soliton dynamics. Soliton interaction dynamics is important for various applications and has quite different manifestations, including e.g. such as bound state solitons [1], soliton rains [2]. Soliton interactions have been observed with different mode locking approaches such as figure-of-eight [3] and nonlinear polarization rotation [4]. Carbon nanotubes (CNT) have recently been widely applied as an efficient saturable absorber for passively mode locked fiber lasers. We have recently studied the polarization dynamics in a CNT mode locked vector soliton erbium doped fiber laser [5]. So far, the polarization dynamics of bound state solitons have yet to be investigated. In this report, we present a wide range of polarization dynamics of bound state solitons generated in a CNT mode locked erbium doped fiber laser. The fiber laser consists of ∼ 2 m highly doped erbium fiber (Liekki Er80-8/125) as the gain medium, an optical isolator to ensure unidirectional oscillation anda 980 nm laser diode is used to pump the gain through the 1550/980 nm wavelength division multiplexer. A fused 10:90 coupler is used to couple 10 % of the light out of the laser cavity and two in-line polarization controllers (NewPort) are used to control the birefringence of the cavity and polarization of the pump light respectively. The total cavity length is ∼ 7.8 m indicating a 25.7 MHz fundamental repetition rate. © 2013 IEEE.

Die Behandlung englischen Kulturgutes im Wiener fin de siècle:am Beispiel von Hugo von Hofmannsthal, Hermann Bahr und Peter Altenberg

This study explores the fascination which English culture represented in turn-of-the-century Vienna. The writers that are going to be discussed are the renowned Anglophile Hugo von Hofmannsthal, the more ambivalent Hermann Bahr and the idealizing, but Janus-faced Peter Altenberg. With the more widely known poet, prose writer and playwright, Hofmannsthal, individual aspects of his engagement with English culture have already been well researched; the same, however, cannot be said in the case of Hermann Bahr, whose extensive literary oeuvre has now largely been forgotten, and who has, instead, come to be valued as a prominent figure in the culture life of modernist Vienna, and Peter Altenberg, whose literary fame rests mainly on his prose poems and who, a legend in his life-time, has in recent years also increasingly attracted research interest as a phenomenon and ‘embodiment’ of the culture of his time: while their engagement with French literature, for example, has long received its due share of attention, their debt to English culture has, until now, been neglected. This thesis, therefore, sets out to explore Hofmannsthal’s, Bahr’s and Altenberg’s perception and portrayal of English civilization – ranging from English character and stereotypes, to what they saw as the principles of British society; it goes on to investigate the impulses they derive from Pre-Raphaelite art (Rossetti, Burne-Jones, Whistler) and the art and crafts-movement centred around William Morris, as well as their inspiration by the art criticism of John Ruskin and Walter Horatio Pater. In English literature one of the focal points will be their reading and evaluation of aestheticism as it was reflected in the life and writings of the Dubliner Oscar Wilde, who was perceived, by these Austrian authors, as a predominant figure of London’s cultural life. Similarly, they regarded his compatriot George Bernard Shaw as a key player in turn-of-the-century English (and European) culture. Hermann Bhar largely identified with him. Hofmannsthal, on the other hand, while having some reservations, acknowledged his importance and achievements, whereas Peter Altenberg saw in Shaw a model to reassure him, as his writings were becoming more openly didactic and even more miniaturistic than they had already been. He turned to Shaw, too, to explain and justify his new goal of making his texts more intelligent to a wider circle of readers.

Margetinggeschichte:Die Genese einer modernen Sozialtechnik, Hartmut Berghoff

Book revew: Marketinggeschichte: die Genese einer modernen Sozialtechnik [Marketing history: The genesis of a modern social technique], edited by Hartmut Berghoff, Frankfurt/Main, Campus Verlag, 2007, 409 pp., illus., [euro]30.00 (paperback), ISBN 978-3-593-38323-1. This edited volume is the result of a workshop at Göttingen University in 2006 and combines a number of different approaches to the research into the history of marketing in Germany's economy and society. The majority of contributions loosely focus around the occurrence of a ‘marketing revolution’ in the 1970s, which ties in with interpretations of the Americanisation of German business. This revolution replaced the indigenous German idea of Absatzwirtschaft (the economics of sales) with the American-influenced idea of Marketing, which was less functionally oriented and more strategic, and which aimed to connect processes within the firm in order to allow a greater focus on the consumer. The entire volume is framed by Hartmut Berghoff's substantial and informative introduction, which introduces a number of actors and trends beyond the content of the volume. Throughout the various contributions, authors provide explanations of the timing and nature of marketing revolutions. Alexander Engel identifies an earlier revolution in the marketing of dyes, which undergoes major change with the emergence of chemical dyes. While the natural dyestuff had been a commodity, with producers removed from consumers via a global network of traders, chemical dyes were products and were branded at an early stage. This was a fundamental change in the nature of production and sales. As Roman Rossfeld shows in his contribution on the Swiss chocolate industry (which focuses almost exclusively on Suchard), even companies that produced non-essential consumer goods which had always required some measure of labelling grappled for years with the need to develop fewer and higher impact brands, as well as an efficient sales operation. A good example for the classical ‘marketing revolution’ of the 1970s is the German automobile industry. Ingo Köhler convincingly argues that the crisis situation of German car manufacturers – the change from a seller's to a buyer's market, appreciation of the German mark which undermines exports, the oil crises coupled with higher inflation and greater frugality of consumers and the emergence of new competitors – lead companies to refocus from production to the demands of the consumer. While he highlights the role of Ford in responding most rapidly to these problems, he does not address whether the multinational was potentially transferring American knowledge to the German market. Similarly, Paul Erker illustrates that a marketing revolution in transport and logistics happened much later, because the market remained highly regulated until the 1980s. Both Paul Erker and Uwe Spiekermann in their contribution, present comparisons of two different sectors or companies (the tire manufacturer Continental and the logistics company Dachser, and agriculture and trade, respectively). In both cases, however, it remains unclear why these examples were chosen for comparison, as both seem to have little in common and are not always effectively used to demonstrate differences. The weakest section of the book is the development of marketing as an academic discipline. The attempt at sketching the phases in the evolution of marketing as an academic discipline by Ursula Hansen and Matthias Bode opens with an undergraduate-level explanation on the methodology of historical periodisation that seems extraneous. Considerably stronger is the section on the wider societal impact of marketing, and Anja Kruke shows how the new techniques of opinion research was accepted by politics and business – surprisingly more readily by politicians than their commercial counterparts. In terms of contemporary personalities, Hans Domizlaff emerges as one fascinating figure of German marketing history, which several contributors refer to and whose career as the German cigarette manufacturer Reemtsma is critically analysed by Tino Jacobs. Domizlaff was Germany's own ‘marketing guru’, whose successful campaigns led to the wide-ranging reception of his ideas about the nature of good branding and marketing. These are variously described as intuitive, elitist, and sachlich, a German concept of a sober, fact-based, and ‘no frills’ approach. Domizlaff did not believe in market research. Rather, he saw the genius of the individual advertiser as key to intuitively ascertaining the people's moods, wishes, and desires. This seems to have made him peculiarly suited to the tastes of the German middle class, according to Thomas Mergel's contribution on the nature of political marketing in the republic. Especially in politics, any form of hard sales tactics were severely frowned upon and considered to demean the citizen as incapable of making an informed choice, a mentality that he dates back to the traditions of nineteenth-century liberalism. Part of this disdain of ‘selling politics like toothpaste’ was also founded on the highly effective use of branding by the National Socialists, who identified their party through the use of an increasingly standardised image of Adolf Hitler and the swastika. Alexander Schug extends on previous research that criticised the simplistic notion of Hitler's charisma as the only explanation of the popular success and distances his approach from those who see it in terms of propaganda and demagogy. He argues that the NSDAP used the tools of advertising and branding precisely because they had to introduce their new ideology into a political marketplace dominated by more established parties. In this they were undoubtedly successful, more so than they intended: as bakers sold swastika cookies and butchers formed Führer heads out of lard, the NSDAP sought to regain control over the now effectively iconic images that constituted their brand, which was in danger of being trivialised and devalued. Key to understanding the history of marketing in Germany is on the one hand the exchange of ideas with the United States, and on the other the impact of national-socialist policies, and the question whether they were a force of modernisation or retardation. The general argument in the volume appears to favour the latter explanation. In the 1930s, some of the leading marketing experts emigrated to the USA, leaving German academia and business isolated. The aftermath of the Second World War left a country that needed to increase production to satisfy consumer demand, and there was little interest in advanced sales techniques. Although the Nazis were progressive in applying new marketing methods to their political campaign, this retarded the adoption of sales techniques in politics for a long time. Germany saw the development of idiosyncratic approaches by people like Domizlaff in the 1930s and 1940s, when it lost some leading thinkers, and only engaged with American marketing conceptions in the 1960s and 1970s, when consumers eventually became more important than producers.