Master of Science

thesisTraditionally, oral tribology research involved the use of polydimethylsiloxane (PDMS) as a substitute for lingual tissue. This allowed researchers to construct custom surfaces with different topographies and varying moduli of elasticity. Although PDMS

Using history in the creation of organizational identity

Organizations frequently draw on history as a resource, for instance when attempting to establish or maintain identity claims. However, little has been done to review the advantages and problems of such use of history and it is not clear how using history impacts on the appreciation of history itself and, ultimately, on the insights that may be gained when engaging with the past. To begin to address these questions we distinguish two related uses of history as a resource for organizational identity: as a means of committing external audiences and, as a way of finding inward commitment. We theorize these two uses by drawing on speech act theory to develop a taxonomy of uses of history and to elaborate the opportunities and challenges that come when historical narratives are fashioned in the service of identity. We conclude with a further insight gained from speech act theory that suggests an engagement with history that requires sensitivity to prevailing conventions at the moment of these historical acts. We argue that appreciation of asynchronous historical conditions and contexts affords new insights through the difference these pose to current and instrumental concerns that otherwise guide the fashioning and interpretation of historical 'facts.

Productivity and Profitability of a Cotton-based Production System under Organic and Conventional Management in India

The debate on the relative benefits of conventional and organic farming systems is more topical than ever. The achievements of conventional high-input agriculture were largely brought about at the cost of deteriorating soil fertility; furthermore, they were based to a large extent on fossil fuels. Developing more sustainable farming practices on a large scale is of utmost importance. However, information about the performance of agricultural production systems under organic and conventional management in tropical and subtropical regions is largely lacking. This study aimed to assess agronomic and economic data from a long-term farming systems comparison trial under semi-arid conditions in central India. Four two-year crop rotations comprising cotton-soybean-wheat under biodynamic, organic and conventional management were investigated, including one conventional system with and one without transgenic Bt cotton, between 2007 and 2010. Results showed 13% lower yields in organic compared to conventional systems. Yields in cotton, soybean and wheat were on average 14 %, 7% and 15% lower, respectively. However, production costs of organic systems were on average 32% lower than those of conventional systems, which led to similar gross margins in all systems. To our knowledge, this is the first long-term field trial comparing the agronomic and economic performance of organic, conventional and conventional+Bt cotton-based farming systems. The results of our study suggest that organic farming is a promising alternative to conventional farming in cotton-based production systems in central India. The less capital intensive nature of organic systems may be particularly interesting for smallholder farmers as it decreases dependence on loans for farm inputs. Therefore, our findings have the potential to be useful for decision-making and in turn may lead to a redirection of agricultural policies

Economic profitability of organic vs. conventional cotton-based production systems in a long-term field trial in India

The debate on the relative benefits of conventional and organic farming systems is more topical than ever. The achievements of conventional high-input agriculture were largely brought about at the cost of deteriorating soil fertility; furthermore, they were based to a large extent on fossil fuels. Developing more sustainable farming practices on a large scale is of utmost importance. However, information about the performance of agricultural production systems under organic and conventional management in tropical and subtropical regions is largely lacking. This study aimed to assess agronomic and economic data from a long-term farming systems comparison trial under semi-arid conditions in central India

Not quite a revolution: scrutinizing organizational neuroscience in leadership studies

Several provocative studies on organizational neuroscience have been published of late, many in the domain of leadership. These studies are motivated by the prospect of being able to better explain what causes and constitutes ‘good’ leadership by examining brain activity. In so doing, these studies follow an established path in organizational research that seeks to reduce complex social phenomena to more basic (neurological) processes. However, advocates of organizational neuroscience reveal very little about the fundamental problems and challenges of reductionism. Therefore, our aim in this article is to scrutinize the reductionist assumptions and processes underlying the fast-evolving domain of organizational neuroscience as it is applied to the study of leadership. We maintain that without explicit consideration of, and solutions to, the challenges of reductionism, the possibilities to advance leadership studies theoretically and empirically are limited. In consequence, inferential ambiguities that flow from such insights run the danger of informing organizational practice inadequately. Thus, we find suggestions that we are at the brink of a neuroscientific revolution in the study of leadership premature, and a sole focus on neuroscience, at the expense of insights from other social science disciplines, dangerous

Spin flip from dark to bright states in InP quantum dots

We report measurements of the time for spin flip from dark (non-light emitting) exciton states in quantum dots to bright (light emitting) exciton states in InP quantum dots. Dark excitons are created by two-photon excitation by an ultrafast laser. The time for spin flip between dark and bright states is found to be approximately 200 ps, independent of density and temperature below 70 K. This is much shorter than observed in other quantum dot systems. The rate of decay of the luminescence intensity, approximately 300 ps, is not simply equal to the radiative decay rate from the bright states, because the rate of decay is limited by the rate of conversion from dark excitons into bright excitons. The dependence of the luminescence decay time on the spin flip time is a general effect that applies to many experiments.Comment: 3 figure

Langzeit-Systemvergleiche in Kenia und Indien: Konventionelle und biologische Erträge aus dem ersten Umstellungsjahr

Organic agriculture is more and more perceived as a promising approach to increase food security in developing countries. However, only few attempts have been made so far to assess agronomic and economic performance of organic agriculture in these^regions in a systematic way. This article reports the first year’s results of two long-term farming systems comparison field trials in Kenya and India. In sub-humid Central Kenya, on a high potential site in Meru South District (Chuka), there were no differences between yields of conventional and organic systems for the first maize and brassica crops. In contrast, organic yields were 14 to 60% lower than conventional yields on a trial site in a medium potential zone in Maragua District (Thika). It is assumed that the organic crops in Chuka could benefit from N and P mobilisation from the soil. In Thika, where N and P were less available, the crop depended on the easily soluble nutrients applied in the conventional treatments. In the semi-arid cotton belt of^Central India, biodynamic, organic, conventional and genetically modified (GM) cotton are compared. Soya and wheat are also part of the crop rotation under study. Biodynamic and organic cotton and wheat yields were 30% lower than conventional and GM yields. Soya yields did not differ between the treatments. It is suggested that yield in organic farming systems in conversion depends on initial inherent soil fertility and crop