Entrepreneurship in Agriculture – Farmer Typology, Determinants and Values

Entrepreneurship in agriculture is becoming of greater importance with the changing framework conditions for agricultural production. The present dissertation analyses this topic from different angles in order to gain a comprehensive picture of the current situation in Germany and to provide politicians, stakeholders and farmers with fundamental insights and implications. Therefore, it consists of three contributions covering different aspects: the first one identifies which different farmer types exist within a comprehensive sample of German farmers in order to generate a starting point and an orientation for agricultural policy design. Three clusters can be identified; conventional growers as important actors for efficient agricultural production, versatile youngsters as innovators within the sector and family-based farmers as important actors for maintaining vivid rural areas. The second contribution sets up which different strategic entrepreneurial choices in agriculture exist and aims at explaining which factors determine the choice of a certain strategy. In general it can be distinguished between reduction, continuation, expansion, diversification and the dual strategy of expansion and diversification. Analysing determinants, strong effects are observable particularly within the area of personal factors, such as creativity or risk attitude, as well as family support. Finally, the third contribution analyses the inner drivers of entrepreneurial action; farmers’ values in order to get a deeper understanding of the underlying motives. Farmers of the sample first and foremost prioritise self-transcendence values followed by openness to change. Conservation and self-enhancement are ranked to be less important within farmers’ value priorities. Furthermore, three different value portraits are identifiable within the sample. These groups differ significantly among other things in their risk attitude and involvement in structural diversification. For the analyses unsupervised machine learning methods are applied in contribution one and three next to a multinomial logit model in contribution two and multidimensional scaling in contribution three. Implications for farmers, policy as well as for actors within the sector are derived.2021-06-1

Regiospecific Reductive Elimination from Diaryliodonium Salts

StereoElectronic Control of Unidirectional Reductive Elimination (SECURE) is provided by the cyclophane substituent on iodine(III). Computational and experimental studies demonstrate that out of plane steric bulk strongly destabilizes the reductive elimination transition state, and leads to regiochemical control. This approach should be general for high valent main group and transition metal ions

Unprecedented Directing Group Ability of Cyclophanes in Arene Fluorinations with Diaryliodonium Salts

For the first time it is shown that exceptionally electron-rich arene rings can be fluorinated exclusively during the reductive elimination reactions of diaryliodonium fluorides. The 5-methoxy[2.2]paracyclophan-4-yl directing group simultaneously reduces unproductive aryne chemistry and eliminates ligand exchange reactions by a combination of steric and electronic effects. Use of the cyclophane directing group permits an unprecedented degree of control in fluorination reactions of diaryliodonium salts. Includes Supporting Information (50 pp.

Controlling Reductive Elimination From Novel I(III) Salts Using a SECURE Method

Positron Emission Tomography (PET) is a valuable clinical, research, and diagnostic technique for human and animal organ imaging. The current market for PET in the United States is $500 million per year and is projected to be$5.4 billion per year globally by 2015. To synthesize labeled radiotracers, we are most interested in using 18F as the isotope of choice because it is a nearly ideal positron emitting radionuclide. Electron-rich aromatic substrates can be particularly difficult to fluorinate. We show that reductive elimination of I(III) diaryliodonium salts provide increased fluorination of electron-rich aromatic substrates. Modest yields of fluorinated product were initially observed due to the lack of regioselectivity in the reductive elimination process. It seemed clear that a better directing group would be needed if extremely electron-rich rings are to be fluorinated in high chemical (or radiochemical) yields using diaryliodonium salts. The use of [2.2]paracyclophane as a directing ligand has been shown by computational and experimental data to provide an increase in steric demand above the plane of the aromatic ring; therefore, destabilizing a reductive elimination transition state. This effect is sufficiently large to provide stereoelectronic control of unidirectional reductive elimination (SECURE) for most nucleophiles; however, benzyne chemistry was observed when fluorine and 2,2,2-trifluoroethoxide were used as nucleophiles. To address the benzyne issue, we have shown that the choice of a judiciously substituted cyclophane substituent on I(III) can provide perfect regioselectivity for reductive elimination of iodocyclophanes and fluorination of electron-rich arenes. This work constitutes the first example of regiospecific fluorination of electron-rich aromatic rings using diaryliodonium fluorides. We believe this discovery paves the way for the synthesis of highly elaborated radiotracers from Ar2IF salts. Advisor: Stephen G. DiMagn

Professional responsibility in dentistry: A practical guide to law and ethics

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Values of farmers: Evidence from Germany

Against the background of fundamentally changing political and social requirements of agricultural production, the requirement profile of farmers has changed. The future of agriculture is widely discussed. To prepare a ground for future debates and policy programme design, it is essential to get an understanding of which values underlie farmers' behaviour. This paper applies SCHWARTZ' value theory to a large quantitative survey (N = 787) of German farmers. Next to the overall value portrait, different value portraits within the sample of farmers are analysed. Farmers of the sample first and foremost prioritise self-transcendence values followed by openness to change. Conservation and self-enhancement are ranked to be less important within farmers' value priorities. Furthermore, three different value portraits are identifiable within the sample. These groups differ significantly among other things in their risk attitude and involvement in structural diversification. Implications for agricultural policy design and agricultural management are derived from the results