Kärin Nickelsen
University of Bern
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Featured researches published by Kärin Nickelsen.
Photosynthesis Research | 2007
Kärin Nickelsen
In the field of photosynthesis research, Otto Warburg (1883–1970) is predominantly known for the role he played in the controversy that began in the late 1930s regarding the maximum quantum yield of photosynthesis, even though by that time he had already been working on the topic for more than a decade. One of Warburg’s first contributions on the subject, which dates from around 1920, is his proposal for a detailed model of photosynthesis, which he never completely abandoned, despite later overwhelming evidence in favor of alternatives. This paper presents a textual and graphical reconstruction of Warburg’s model and of his argument for its validity. Neither has received much attention in the history of science, even though the model was certainly one of the most plausible explanations of the period and therefore could not be so easily discredited.
Archive | 2004
Kärin Nickelsen; Alessandra Hool; Gerd Graßhoff
Anfang Oktober 1954 erhielt Theodore von Karman folgende Nachricht von Jacques Boesch aus Bern: nLaut Telegramm Ihres Bruders Ausreise Bewilligung Zugesprochen Visa Erhalten Stop Ich Liess Zweitausend Francs Fuer Reisespesen Ueberweisen Laut Wunsch Ihres Bruders Stop Rechne Mit Ankunft Naechster Woche Stop Werde Mich Seiner Annehmen Stop Herzlichst Jacques Boesch.1
Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences | 2009
Kärin Nickelsen
In the years 1919 to 1923, Otto Warburg published four papers that were to revolutionise the field of photosynthesis. In these articles, he introduced a number of new techniques to measure the rate of photosynthesis, put forward a new model of the mechanism and added a completely new perspective to the topic by attempting to establish the processs efficiency in terms of the light quantum requirement. In this paper I trace the roots of Warburgs series of contributions to photosynthesis research by exploring three different contexts of inspiration: Warburgs own research into cell respiration, his fathers work on the quantum yield of photochemical reactions in general and the photosynthesis work carried out by Richard Willstätter and Arthur Stoll. When these influences are considered together, it becomes clear that Warburg implemented a Building Block Strategy in his research: rather than inventing his photosynthesis model from scratch, he availed himself of fragments from other contexts, which he then recombined in a new and innovative way. This way of working is considered to be standard practice in scientific research.
Archive | 2013
Govindjee; Lars Olof Björn; Kärin Nickelsen
We start with the discussion of the photosynthetic unit, based on the experiments of Emerson and Arnold (1932a, 1932b), continue with the first two-quantum proposal by Rabinowitch (1945, 1956), Emerson’s Red drop (1943) and Emerson Enhancement Effect (1957) and various action spectra made for understanding the roles of the photosynthetic pigments. The experimental work of Kok (1959) and the theoretical model by Hill and Bendall (1960) were followed soon thereafter by the seminal papers of Duysens et al. (1961) and Duysens and Amesz (1962), in which the two photosystems were shown to be connected, in series, by cytochrome, which can be photooxidized by photo system I and photoreduced by photosystem II. Further, Witt et al. (1961) and others, cited in this paper, made refinement of the Z-scheme.
Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences | 2011
Kärin Nickelsen; Gerd Graßhoff
Falsification no longer is the cornerstone of philosophy of science; but it still looms widely that scientists ought to drop an explanatory hypothesis in view of negative results. We shall argue that, to the contrary, negative empirical results are unable to disqualify causally explanatory hypotheses-not because of the shielding effect of auxiliary assumptions but because of the fact that the causal irrelevance of a factor cannot empirically be established. This perspective is elaborated at a case study taken from the history of plant physiology: the formaldehyde model of photosynthesis, which for about sixty years (1870s to 1930s) dominated the field-despite the fact that in these sixty years all the attempts to conclusively demonstrate even the presence of formaldehyde in plants failed.
Ntm | 2016
Kärin Nickelsen; Fabian Krämer
Third party funding, publications in pertinent journals, top spots in rankings or excellent PhD students: these are some of the rewards for which scientists and scientific institutions strive and compete. Often, the dynamics of modern science—which we understand in this introduction in the broad sense of the German termWissenschaft—are reduced to an all-out competition. This view, however, tends to conceal the fact that scholars are in numerous ways part of cooperative structures. More often than not, they pursue their research goals as part of a larger group, share their insights and results with colleagues, and exchange ideas at conferences. Without cooperation, Wissenschaft would be unthinkable, be it the deciphering of the human genome, the proof of existence of the Higgs-Boson or the edition of ancient Latin inscriptions, such as the Corpus Inscriptionum Latinarum. Contrary to the widely held view, cooperation and competition are not antonymous modes of interaction: non-collaborating scientists are not necessarily competitors, and vice versa. Neither are these modes mutually exclusive. In fact, in the sciences cooperation and competition seem to be closely connected. In order to successfully compete with others, scientists have to be firmly embedded in collaborative structures; and they have to comply with norms and conventions of mutual support and acknowledgement (e.g. Felt et al. 1995: 70–83). These structures, norms and conventions are historically and culturally contingent. The prevailing mode of interaction depends on circumstances and historical setting, and is constantly under negotiation, because neither all-in cooperation nor all-out competition results in stable final configurations: collaboration partners can quickly become rivals; while groups in sharp competition can change into collaborative hunting packs. In Germany, we have had in recent years ample opportunity to observe N.T.M. 24 (2016) 119–123 0036-6978/16/020119-05 DOI 10.1007/s00048-016-0145-4 Published online: 13 May 2016 2016 SPRINGER INTERNATIONAL PUBLISHING
Archive | 2004
Kärin Nickelsen; Alessandra Hool; Gerd Graßhoff
„Die Ara Franz Josephs [war] im Ganzen gesehen eine frohliche Zeit - eine herrliche Zeit, hineingeboren zu werden“1, so beschrieb Theodore von Karman ruckblickend seine Kindheit im Budapest des spaten 19. Jahrhunderts2. Seine Mutter, Helene Konn, stammte aus einer wohlhabenden judischen Gelehrtenfamilie mit beachtlichem Stammbaum; der Vater, Maurice Karman, war Ungarns fuhrender Padagoge. 1869, als Ungarn sich als eigener Staat formierte, war er massgeblich daran beteiligt, das ungarische Schulsystem zu modernisieren und nach deutschem Vorbild umzugestalten. Zur praktischen Erprobung seiner padagogischen Ideale grundete Maurice Karman zudem in Budapest eine eigene Schule, die so genannte Minta („Mustergymnasium“), worin die Schuler mit modernen Methoden zum selbststandigen Denken angeleitet werden sollten3. Aufgrund seiner Erfolge mit dieser Schule wurde Maurice Karman schliesslich beauftragt, die Schulbildung eines Verwandten des Kaisers Franz Joseph I. zu betreuen, und wurde fur diese Bemuhungen 1907 in den Erbadel erhoben.
Archive | 2004
Kärin Nickelsen; Alessandra Hool; Gerd Graßhoff
Wahrend Theodore von Karman in diesem Sinne auf der Weltbahne wie auch in den Provinzialgerichten Deutschlands seinen Einfluss geltend machte, verfolgte er in der Schweiz ein ganz anderes Projekt. Inzwischen aber siebzigjahrig, begann er nun fur die Zeit nach seinem Tod zu sorgen.
Archive | 2004
Kärin Nickelsen; Alessandra Hool; Gerd Graßhoff
Im Fruhjahr 1953 beschloss die neue republikanische Regierung der USA unter Prasident Eisenhower, den Krieg in Korea notfalls durch den Einsatz von Atombomben zu beenden. Dazu sollte es zwar nicht mehr kommen: Im Juli 1953 schlossen die Kriegsparteien einen Waffenstillstand, der die Grenze zwischen Nord-und Sud-Korea auf den 38. Breitengrad festlegte; doch war mit Eisenhowers Beschluss eine prinzipielle Entscheidung uber die Verwendung von Atomwaffen gefallen, die uber den ersten Einsatz im August 1945 hinausreichte. Eine Entspannung zwischen Ost und West war damit auch nach Kriegsende nicht in Sicht — im Gegenteil. In den Vereinigten Staaten stieg der Verteidigungshaushalt im Jahr 1953 auf insgesamt 50 Milliarden Dollar; verglichen mit dem Budget im Jahr 1951 bedeutete dies eine erneute Verdoppelung der Rustungsausgaben. Gleichzeitig wurde die Militarhilfe an die Bundnispartner massiv verstarkt, die NATO wurde ausgebaut, und in der Bundesrepublik Deutschland begann die Wiederbewaffnung.
Archive | 2004
Kärin Nickelsen; Alessandra Hool; Gerd Graßhoff
Bevor wir das weitere Schicksal von Miklas, Margit und der Erbschaft verfolgen, lohnt es sich, noch einmal einen Blick auf Theodore von Karmans sonstige Verbindungen zur Schweiz zu werfen, neben seinen Beziehungen zu Jacques Boesch und Horace Mastronardi, die sich im Zuge der Ausreisebemahungen stark intensivierten. In die fruhen 1950er Jahre fiel eines der ehrgeizigsten Projekte des Schweizer Militars: die Entwicklung eines eigenen Kampfflugzeugs — ein Projekt, an dem sowohl Karman selbst als auch die meisten seiner Schweizer Bekannten auf verschiedene Weise beteiligt waren.