O objetivo deste trabalho é descrever como as empresas pesquisadas implementaram seus sistemas da qualidade, procurando identificar as diferenças e semelhanças entre a implementação em pequenas e médias empresas, bem como as diferenças e semelhanças entre a implementação da ISO 9000 e da QS-9000. A partir da pesquisa bibliográfica foram levantados os aspectos mais importantes para a implementação do sistema da qualidade, que depois foram agrupados em categorias e serviram de base para a elaboração do modelo conceitual. Para o estudo múltiplo de caso, oito empresas participaram da pesquisa de campo através de entrevistas semi-estruturadas, sendo que para cada combinação de norma e tamanho haviam duas empresas. Após a descrição dos casos foi feita a análise em profundidade de acordo com as categorias: administração, recursos, gestão de RH, planejamento, apoio técnico, organização e tecnologia existentes antes da implementação e resultados obtidos com a implementação. Os resultados desta pesquisa indicam que tanto para as empresas pequenas como para as médias têm sido utilizadas várias formas para a implementação do sistema da qualidade e as principais diferenças encontradas deveram-se ao tipo de norma aplicada (ISO 9000 ou QS-9000). Finalmente são feitas algumas recomendações práticas para a implementação de sistemas da qualidade. / The purpose of this study is to describe how the companies investigated has been implemented your quality system, to looking for identify the differences and similarity between the implementation in small and medium companies, as well as the differences and similarity between the implementation of the ISO 9000 and the QS-9000. From the bibliografical research were risen the most important aspects for the quality system implementation, after they were clustered in categories and they were used to support for the conceptual model preparation. To the multiple case study, eight companies took part in the field research through semi-structured interviews, being for each standard and size arrangement there were two companies. After the cases description was made the in depth analysis in accordance to the categories: management, resources, HR management, planning, technical support, existent organization and technology before the implementation and the results achieved with the implementation. The results of this research indicate such as small companies such as for the medium have been used many ways to quality system implementation and the main differences was found occured by to the standards used (ISO 9000 or QS-9000). Finally some practical recomendations are made to the quality system implementation.

Die vorliegende Arbeit geht der Frage nach, ob und inwiefern sich die Biogasproduktion sowohl im Allgemeinen als auch im Speziellen unter den Richtlinien des EEG 2012 auf die Wettbewerbsfähigkeit anderer landwirtschaftlicher Produktionsverfahren auswirkt. Dafür werden innerhalb Niedersachsens vier Regionen auf Gemeindeebene identifiziert, die sich durch Produktionsschwerpunkte landwirtschaftlicher Tätigkeiten charakterisieren lassen. Hierunter fallen Milchviehhaltung, Veredlung in der Schweine- und Bullenmast, Ackerbau mit dem Fokus auf Kartoffelanbau und schließlich gemischter Ackerbau. Die Vorgehensweise und das Ergebnis dieser Einteilung sind als völlig neu zu bewerten und münden in jeweiligen Intensivregionen der entsprechenden Betriebsausrichtungen. Das Instrument der Betriebszweigauswertung wird herangezogen und anhand eines eigenen Modells angepasst. Dies ermöglicht, zwischen dem jeweils regional anzusiedelnden Verfahren und ansässiger Biogasproduktion die ökonomischen Vor- und Nachteile im Wettbewerb festzustellen. In einem zweiten Schritt gibt eine Betriebsleiterbefragung Aufschluss darüber, wie die Wettbewerbsfähigkeit seitens der Biogas- und Nichtbiogasbetreiber empfunden wird. Darüber hinaus fängt die Befragung die maximalen Faktorentlohnungen der Betriebsleiter ein. Somit ergänzen sich die objektive und subjektive Messung betrieblicher Wettbewerbsfähigkeit. Die Ergebnisse der vorliegenden Arbeit kommen wie erwartet zu dem Schluss, dass die Biogasproduktion in den von Viehwirtschaft gekennzeichneten Regionen Niedersachsens Wettbewerbsvorteile besitzt. Dieser Vorteil ist in der von Milchviehhaltung geprägten Region aber geringer als bislang angenommen. Während sich die Biogasproduktion mit gemischtem Ackerbau auf gesamtwettbewerblicher Augenhöhe befindet, sehen sich die Landwirte in der von Kartoffelanbau charakterisierten Region gegenüber Biogasbetrieben in einem Wettbewerbsnachteil, der allerdings objektiv nicht nachgewiesen werden kann. / This paper examines the question of whether and to what extent biogas production has an impact on the competitiveness of other agricultural production methods, both in general and in particular under the German Renewable Energy Act (EEG) 2012 guidelines. For this purpose, four regions at municipal level within Lower Saxony are identified which can be characterised by production focuses of agricultural activities. These include dairy farming, pig and bull fattening, arable farming with a focus on potato cultivation and finally mixed arable farming. The procedure and the result of this classification are to be considered as completely new and lead to the respective intensive regions of the respective operational orientations. The instrument of the branch analyses is used and adapted on an own model. This makes it possible to determine the economic advantages and disadvantages in competition between the respective regionally based process and the local biogas production. In a second step, a survey of farm managers provides information on how the competitiveness of biogas and non-biogas operators is perceived. In addition, the survey captures the maximum factor remuneration of the farm managers. Thus, the objective and subjective measurement of operational competitiveness complement each other. As expected, the results of the present study conclude that biogas production has competitive advantages in the regions of Lower Saxony characterised by livestock farming. However, this advantage is lower than previously assumed in the region dominated by dairy farming. While biogas production with mixed arable farming is on a level with overall competition, farmers in the region characterised by potato cultivation see themselves at a competitive disadvantage compared to biogas farms, which however cannot be objectively proven.

Spargelanlagen werden fast ausschließlich durch Pflanzung einjähriger Kronen im Frühjahr etabliert. Die spätere Ertragsleistung wird neben verschiedenen Maßnahmen in der Kulturführung auch maßgeblich vom Wachstum der Pflanzen im ersten Standjahr beeinflusst. In der vorliegenden Arbeit wurde der Einfluss unterschiedlicher Merkmale und Maßnahmen bei Spargeljungpflanzen anhand von Feld- und Gefäßversuchen auf das Wachstum im ersten Standjahr untersucht. Als wichtigstes Kriterium zur Beurteilung der Qualität von Spargeljungpflanzen hat sich eine hohe Pflanzmasse im Frühjahr herausgestellt. Jeweils im Vergleich zu 100-g-Pflanzen im Frühjahr war bei 50g der Verlust an Zuwachs jedoch größer, als der Zugewinn bei 150g. Aus diesem Grund ist nicht nur die durchschnittliche Pflanzmasse für eine gute Etablierung von Interesse, sondern auch der Anteil kleinerer Pflanzen. Ein Verlust an Wurzelmasse brachte bis auf die Auswirkungen der geringeren Pflanzmasse keine zusätzlichen Effekte auf die Etablierung. Auch der Gehalt löslicher Reservekohlenhydrate im Frühjahr erwies sich von eher untergeordneter Rolle. Bezüglich unterschiedlicher Behandlungen vor der Pflanzung konnten keine ausgeprägten Effekte der Temperatur bei einer kurzfristigen Lagerung und eines unterschiedlichen Pflanztermins bzw. der Lagerdauer nachgewiesen werden. Zwar zeigte sich bei einer Lagerung von über zwei Monaten eine Reduktion der Laub- und Kronenmasse im Herbst, jedoch ist die Ursache hierfür eher in der Verkürzung der Vegetationszeit zu suchen. Als ein wichtiges Qualitätsmerkmal sind in Fungizidlösungen getauchte Pflanzen (Beizung) zu nennen. Zwar ergaben sich je nach Pflanzbedingungen nicht in jedem Fall fördernde Effekte, in der Summe der Versuchsauswertungen über mehrere Jahre und Mittel war aber eine deutliche Steigerung des Wachstums durch Tauchbehandlungen nachzuweisen. Da auch die alleinige Tauchung der Jungpflanzen in Wasser zu einer Vitalitätssteigerung führte, sollte die Beizung möglichst direkt vor der Pflanzung durchgeführt werden. Als Fazit der vorliegenden Untersuchungen ist bezüglich der Jungpflanzenqualität bei Spargel vornehmlich auf gleichmäßig hohe Pflanzmassen sowie einer kurz vor der Pflanzung erfolgten Beizung Wert zu legen. / Asparagus plantings are usually established by planting one year old crowns in the spring. The later yield potential is influenced by culture practical measurements and the growth of the plants in the first year. This work deals with the influence of different characters and measurements of young asparagus plants on the growth in the first year by trials in the field and pots. The most important criterion of the evaluation of the quality of asparagus plants had been the weight of the plants in spring. Comparing with 100-g-plants in the spring the lack of growing of plants with 50g was higher than the better growing with 150g. So it is not only interesting to have a high average plant weight for a good establishment of an asparagus planting but although the part of smaller plants. A lack of root weight showed not more effects than only the lack of plant weight. Although the content of soluble concentration of carbohydrates in the spring showed no to be important. Due to different treatments before planting there were no strange effects of the temperature during a short storage and a different time of planting or period of storage. There was a reduction of fern- and crown weight in autumn after storage before planting over a period of two months, but the reason seems to be the reduction of the vegetation period. An important criterion of quality is a preplant fungicide dip for asparagus crowns. Although because of different conditions after planting there was not every time a better establishment of the plants, but in consideration of all trials in different years and fungicides there was a significant increase of the growth because of dipping treatments. Because the dipping of the crowns only in water before planting showed effects of a better vitality the fungicide dips should be done directly before planting. The result of this work concerning the quality of asparagus crowns is a constant high crown weight and a fungicide dip just before planting.

Eine geringe Wertschätzung von Zwischenhändlern wie in vielen Entwicklungsländern ist auch in Ghana vorzufinden, was einerseits aus geschichtlichen Gründen aber auch aus Unwissenheit entsteht. Der Bereich der Zwischenhändler ist vorwiegend durch Frauen aus ruralen Gebieten betrieben, die Analphabeten und Autodidakten sind. Der Handel ist auf jeder Ebene organisiert, von den Kommunen über die Distriktstädte, die regionalen Hauptstädte und auch über die Grenzen des Landes hinaus. Die Händlerinnen organisieren damit den Warenfluss von den entlegenen Plätzen der Produktion oder aus dem Ausland, um es zu den Märkten mit der Nachfrage in den Ballungszentren und den großen städtischen Märkten zukommen zu lassen. Nichtsdestotrotz werden bei diversen Programmen der Entwicklungsorganisationen die Händler und vor allem Händlerinnen außen vor gelassen, die Konzentration und Aktivitäten wird auf die Produktion und teilweise auf die Handhabung nach der Ernte fokussiert. Der Wertschöpfungsketten-Ansatz verfolgt jedoch per definitionem alle Akteure in der Kette der Wertschöpfung, allein hierbei fehlen die Händler in der Umsetzung. Die Arbeit soll daher aufzeigen, welche Funktionen die Händlerinnen in den drei ausgewählten Fällen übernehmen und wie somit die Entwicklung von Wertschöpfungsketten optimiert werden und letztendlich die beteiligten Händlerinnen zu einer Verbesserung der Wertschöpfungskette beitragen können. / Trade is a widespread occupation for women in West Africa; such as petty traders that are involved with informal trade mainly. The case in Ghana is different as most of these traders are facing hostile treatment and harassment from many sides. Nevertheless, in development cooperation projects, rural economic development and development of its population is often targeted; whereas solely rural development projects have become projects to support value chains and its stakeholders. These value chains start at agricultural production, further on to processing and altering the raw product until its final condition for sale to the end consumer. The entire value chain deals with many diverse actors in rural and urban areas and also diverse areas of economies, such as micro and small enterprises, and other in private sector or public sector. Therefore, development cooperation dealing with value chain enhancement would address all actors. In Ghana, mainly production side and post-harvest management are dealt with and trade or intermediary trade is circumvented. Some projects openly state that they leave out traders from their interventions in value chains. Most prejudices of this type have derived from historical events and official institutions, also a lack of knowledge. Traders are by contrast those who are coordinating streams of goods from beyond borders to supply to domestic markets and vice versa, manage large quantities for export. The reason that women continue to work in trade is that they barely have alternatives.

Die Ernährungssicherung der Bevölkerung im ländlichen Raum in Sub-Sahara Afrika ist eine der dringlichsten Herausforderungen unserer Zeit. Der Großteil der Bevölkerung ist von der eigenen landwirtschaftlichen Produktion für die Ernährung und die Existenzsicherung abhängig. Eine nachhaltige Entwicklung kleinbäuerlicher Landwirtschaft ist daher eine Grundvoraussetzung für Ernährungssicherung und Armutsbekämpfung. Eine Vielzahl von Entwicklungsmaßnahmen zielt auf die Verbesserung der Agrarproduktion von Kleinbauern und Kleinbäuerinnen ab, um die Ernährungssituation zu verbessern. Die Konsequenzen dieser Entwicklungsmaßnahmen sind oft vielfältig; neben gewollten, intendierten Wirkungen, können sich Entwicklungsmaßnahmen auch negativ auswirken. Daher ist es essentiell ein ex-ante impact assessment vor der Umsetzung durchzuführen, um eventuelle negative Auswirkungen frühzeitig zu identifizieren und die geplanten Maßnahmen dementsprechend anzupassen. Der theoretische Diskurs hinsichtlich der Charakteristika von ex-ante sustainability impact assessment ist sehr umfassend erarbeitet. Hier werden vor allem die gleichwertige Integration der drei Nachhaltigkeitsdimensionen (Soziales, Wirtschaft und Ökologie), die aktive Partizipation verschiedener Stakeholder auf unterschiedlichen Ebenen und der Austausch- und Lernprozess in den Mittelpunkt gerückt. In der Praxis wird die lokale Bevölkerung hingegen selten in ex-ante Wirkungsanalysen von geplanten Entwicklungsmaßnahmen involviert. Auch wenn in sustainability impact assessment ein interaktiver Einbezug der lokalen Bevölkerung unterstrichen wird, existieren kaum einfach anwendbare methodische Vorgehensweisen, um dies durchzuführen. Zudem gibt es bisher nur wenige Fallstudien, die das Einbeziehen von lokalen Stakeholdern beschreiben, systematisch analysieren und den Mehrwert für die Planung von landwirtschaftlichen Entwicklungsmaßnahmen herausstellen. Die vorliegende Arbeit hat zum Ziel diese Forschungslücke zu schließen. Im Rahmen der Dissertation wurde ein methodischer Ansatz für ein ex-ante sustainability impact assessment für die Anwendung mit der lokalen Bevölkerung entwickelt. Diese Methode wurde angewendet, um die positiven und negativen Auswirkungen von geplanten landwirtschaftlichen Entwicklungsmaßnahmen aus Sicht der Kleinbauern und Kleinbäuerinnen zu analysieren. Die Forschung wurde in vier Dörfern im semi-ariden Dodoma und im semi-humiden Morogoro in Tansania durchgeführt. / Food security remains a major challenge in Sub-Saharan Africa. Sustainable agricultural development is fundamental for food security and poverty alleviation, notably in developing countries. Many development initiatives focus on enhancing smallholder production because the majority of poor people in developing countries live in rural areas where agriculture is the main source of livelihood. However, the consequences of these development initiatives are often diverse, having intended effects as well as unforeseen adverse impacts. Therefore, there is a need to assess development strategies/projects prior to their implementation to reduce the risk of possible negative impacts and to allow for adjustments, if necessary. This can be achieved by applying ex-ante sustainability impact assessment. The theoretical discourse on ex-ante sustainability impact assessment is comprehensive, emphasising the equal integration of all three sustainability dimensions (social, economic and environmental), the active involvement of stakeholders at every step of the assessment process and a focus on exchange and learning among the involved stakeholders. In practice, local communities are rarely involved in ex-ante impact assessment. Moreover, despite a strong emphasis on their involvement in theory, there remains a lack of easily applicable frameworks for sustainability impact assessment. Hence, there are only few concrete case studies having analysed the value added by applying sustainability impact assessment with local stakeholders and its benefit for planning agricultural measures to enhance food security and sustainable development. This PhD thesis closes the gap by developing and applying an ex-ante impact assessment approach that is based upon the Framework for Participatory Impact Assessment (FoPIA) method and is applicable at small-scale farmer level in the development context. The framework was applied to assess the sustainability of upgrading strategies along the farmers’ food value chains to improve food security in rural Tanzania at four contrasting case study villages in the semi-arid Dodoma Region and the semi-humid Morogoro Region.

This thesis aims at implementing methods for factorisation of large numbers. Seeing that there is no deterministic algorithm for finding the prime factors of a given number, the task proves rather difficult. Luckily, there have been developed some effective probabilistic methods since the invention of the computer so that it is now possible to factor numbers having about 200 decimal digits. This however consumes a large amount of resources and therefore, virtually all new factorisations are achieved using the combined power of many computers in a distributed system. The nature of the distributed system can vary. The original goal of the thesis was to develop a client/server system that allows clients to carry out a portion of the overall computations and submit the result to the server. Methods for factorisation discussed for implementation in the thesis are: the quadratic sieve, the number field sieve and the elliptic curve method. Actually implemented was only a variant of the quadratic sieve: the multiple polynomial quadratic sieve (MPQS).

The individual behaviour of prokaryotic organisms such as bacteria often gives rise to complexity that is commonly associated with multicellular behaviour. The transition from unicellular to multicellular behaviour occurs in response to chemical signals, called autoinducers, which bacteria generate and receive internally within a given population. These autoinducers control the gene expression necessary for the emergence of group-behaviour-phenotype. This phenomenon is called quorum sensing (QS). An example of the quorum sensing control of gene regulation has been the luminescence (lux) operon in Vibrio fischeri. The luxI and ainS quorum signalling systems work in conjunction to regulate luminescence in V. fischeri. LuxI and AinS are acyl-synthases that catalyse the production of the autoinducers C6-HSL and C8-HSL respectively. These autoinducers bind to LuxR, a transcriptional activator of the lux operon, which activates expression of the lux genes causing an increase in luminescence. It was shown that quorum signalling also affects motility and biofilm formation in bacteria. However, the evidence with respect to these phenotypes is conflicting and inconclusive, the reason being the state of quorum is ambiguously defined. It is not properly known whether the observed collective behaviour is purely a result of physical crowding of bacteria, or that both chemical signalling and crowding contribute to this phenomenon. This work attempts to address these issues by studying luminescence, motility, and biofilm, a diverse set of behaviours, yet closely linked to each other in V. fischeri-squid symbiosis. We studied the luminescence response of V. fischeri to both endogenous and externally added signals at per-cell and population level. Experiments with ES114, a wild-type strain of V. fischeri, and ainS mutant showed that (i) luminescence per cell does not mutually correlate with the cell-density, indicating that bacteria do not show greater response to the signal at higher densities; (ii) the activity of the lux signalling circuit shows a strong dependence on the growth stage, (iii) the cells do not show enhanced growth, i.e., they do not derive fitness benefits at higher densities in response to the signal. We anticipated that the culture with a higher cell-density should exhibit greater per-cell-luminescence. However, we found that the luminescence curve of the culture with lower density crosses that of the cultures with higher densities during the exponential phase. Kinetic modelling of the luxI mRNA expression showed that the expression profile qualitatively agrees with the luminescence trend observed in the cultures, supporting the observation that growth-phase plays a major role in regulating the luminescence gene expression. We also studied the effect of autoinducers on motility of V. fischeri. V. fischeri uses flagella to move into the inner crypts of the light organ of the squid. The bacterium secretes autoinducers, encounters secretions of the light organ, and slows down during the final stage of colonization process. Studies have shown that flagellar elaboration is repressed as a consequence of ainS signalling. However, those studies were soft-agar migration assays and carried out with the mutant strain of ainS. We measured real-time planktonic motility of ES114 and the signalling mutant strains of V. fischeri in response to autoinducers added exogenously at different concentrations. We found that the autoinducers do not affect the motility of the strains. We also showed that reduction in motility is purely a consequence of physical crowding of bacteria, and chemical signalling may not be involved in the process. It was shown that reduction in motility leads to biofilm formation. Motile bacteria must lose flagella in order to form biofilm, and signalling controls biofilm formation in many species. Our study on motility showed that reduction in motility occurs because of physical crowding in V. fischeri. Hence, we explored the possibility that physical crowding might lead to formation of biofilm rather than signalling in this species. We quantified exopolysaccharide production by crystal violet assay, which revealed that planktonic cells produce exopolysaccharides, in addition to biofilm cells. The study revealed that V. fischeri cells always produce exopolysaccharides irrespective of their physiological state. We examined the effect of signalling on biofilm in ES114 and the mutant strains using gene-expression analysis. We quantified the expression of various genes involved in biofilm formation and found that both ES114 and the mutants expressed rscS and sypP indicating that exopolysaccharide production is not under the control of autoinducers. Therefore, we hypothesized that biofilm formation in V. fischeri may be a result of physical agglomeration of cells. Our observations indicate that the state of quorum is inadequately defined and there is no direct measure of the underlying process. Multicellular behaviour in V. fischeri is regulated by a complex interplay of cell-density, signalling, and other factors such as the growth phase of the culture, indicating that the state of quorum employs different mechanisms to regulate various phenotypes. Our study reveals that QS is an intricate process, and the accepted mechanisms for QS are incomplete at best.

Die vorliegende Studie ist ein Beitrag zu einem wachsenden Bestand zeitgenössischer wissenschaftlicher Arbeiten zur politischen Ökonomie staatlich getriebenen Agrarwandels. Arbeiten zum Thema fragen, wie und warum Agrarwandel stattfindet und welches „Ergebnis“ dieser Wandel vor dem Hintergrund der vielfältigen sozialen und ökologischen Funktionen der Landwirtschaft haben sollte. Die Studie leistet zwei wesentliche Beiträge. Der erste Beitrag ist eine vertiefte empirische Fallstudie zur politischen Ökonomie des agrarischen Wandels auf der Kızıltepe Ebene inmitten der stark verarmten und notorisch gewalttätigen Region Südostanatolien. Der zweite Beitrag liegt in einer Integration von empirischen und theoretischen Arbeiten verschiedener Denkschulen und Disziplinen. Statt in epistemischen Silos zu verharren, wird hier argumentiert, dass die Integration verschiedener Perspektiven vielversprechend und notwendig ist, um die Forschung über den Agrarwandel voranzutreiben. Dies erfolgt zunächst durch eine bewusste und systematische Nutzung von Literatur aus verschiedenen Denkschulen und Wissenschaftsbereichen. Zweitens wird auf der Grundlage des von Hagedorn (2008) entwickelten Institutions of Sustainability Frameworks ein integrativer theoriebasierter Analyserahmen vorgestellt. Wichtige Bausteine hierfür ergeben sich aus Ansätzen der neoklassischen Agrarökonomie, der marxistischen Politischen Ökonomie und ökonomischer Theorien institutionellen Wandels. Die Fallstudie zeigt, wie staatliche Politik zu einer grundlegenden Veränderung der Agrarproduktion im Sinne einer deutlichen Intensivierung und Produktivitätssteigerung geführt hat. Gleichzeitig hat der Agrarwandel, im Widerspruch zu offiziellen Verlautbarungen zu schwerwiegenden negativen Auswirkungen auf die sozialen Produktions- und Reproduktionsbeziehungen und zu massiven ökologischen Problemen geführt. Der Agrarwandel in Kızıltepe erscheint so vor allem als Negativbeispiel staatlicher Einflussnahme. / This study is a contribution to a growing body of research on the political economy of state-driven agrarian change. Scholarship on agrarian change commonly asks how, why and to what end agrarian change occurs. Related to this is an on-going debate about what “kind of agriculture” humanity should strive for to fulfil multiple social purposes and meet ecological needs today and in the future. The study’s contribution is twofold. First, it provides an in-depth empirical case study on the political economy of agrarian change on south-eastern Turkey’s Kızıltepe plain. The plain is located amidst Turkey’s impoverished and violence-stricken South-east Anatolia region, which has been at the centre of major development efforts since the late 1990s. Second, the study seeks to integrate empirical and theoretical works from different epistemic communities. In stressing the need to avoid the common tendency of remaining within epistemic silos, the study argues that integrating these different perspectives is both promising and necessary to further advance research on agrarian change. Using Hagedorn’s (2008) Institutions of Sustainability framework as a point of departure, an integrative theory-based analytical framework is introduced. Important building blocks are derived from neoclassical agricultural economics, Marxist agrarian political economy and economic theories of institutional change. The case study shows how the state’s policies have resulted in a fundamental change to the modus operandi of local agricultural production. State intervention has been highly successful in catalysing intensification and productivity. Yet, contrary to official claims, agrarian change has not yielded prosperity and growth across all social strata. Intensified agriculture has led to severe repercussions for the social relations of production and reproduction and major ecological problems. Agrarian change in Kızıltepe is thus much less a success story, but rather a cautionary tale.

Aus theoretischer und empirischer Sicht ist zu diskutieren, ob die Genossenschaften positive Auswirkungen für ihre Mitglieder haben. Das Forschungsziel dieser Dissertation ist die Erklärung und Bewertung der Auswirkungen, die landwirtschaftliche Genossenschaften auf ihre Mitglieder in diesen Kontexten haben. Die Leitfragen lauten: (1) welches sind die sozioökonomischen Merkmale der Landwirte, die Mitglieder von Genossenschaften sind? und (2) welche spezifischen Auswirkungen haben landwirtschaftliche Genossenschaften auf ihre Mitglieder? Die Fragen werden in einer systematischen Literaturarbeit und drei empirischen Artikeln behandelt. Die systematische Literaturrecherche zeigt die empirischen Belege für positive Effekte von Genossenschaften finden sich in den Kategorien Zugang zu und Nutzung von landwirtschaftlichen Betriebsmitteln, Einkommen, Preise sowie Status und Entscheidungsmacht von Frauen. Im zweiten und dritten Artikel werden die Eigenschaften der Mitglieder und Preiswirkungen von Genossenschaften im argentinischen Wein- und Milchsektor untersucht. Landwirte, die an Genossenschaften verkaufen, erhalten in den untersuchten Fällen niedrigere Preise für ihre Produkte als Landwirte, die an anlegerorientierte Unternehmen verkaufen. Das vierte Papier analysiert Mechanismen, die zur Inklusion benachteiligter Haushalte in sambischen Maisgenossenschaften beitragen. Inklusion entwickelt sich in Genossenschaften, die Engagement zeigen und entweder vulnerable Mitglieder mit Finanzdienstleistungen versorgen, soziale Identität fördern oder benachteiligte Mitglieder dafür entschädigen, dass sie keinen Zugang zu subventionierten Betriebsmitteln haben. Die Gesamtergebnisse zeigen, dass Genossenschaften im Allgemeinen mit den am stärksten benachteiligten Landwirten zusammenarbeiten. Sie erzielen verschiedene positive Wirkungen für ihre Mitglieder. Dennoch gibt es auch einen relevanten Anteil von Fällen, in denen es nicht genügend empirische Belege für ihre Auswirkungen gibt. / From both theoretical and empirical perspectives, whether cooperatives provide their members with benefits remains open to debate. The research objective of this thesis is to explain and assess the effects agricultural cooperatives have on their members in developing contexts. The guiding questions are: (1) what are the socio-economic characteristics of farmers who participate in cooperatives? and (2) what are the specific effects of agricultural cooperatives on their farmer members? The questions are addressed in a systematic literature review and three empirical papers. The systematic literature review finds that what is known about cooperatives is based upon a very limited set of cases. The most conclusive evidence of positive effects corresponds to the categories access to and use of inputs, income, prices and women’s status and agency. The Paper Two and Three explore member characteristics and price effects of cooperatives and Investor-Oriented Firms in the Argentinean non-varietal wine and dairy sector, respectively. Farmers selling to cooperatives receive lower prices than farmers selling to Investor-Oriented Firms in the studied cases. Since cooperative members differ from other farmers in terms of size, assets and the cost of accessing the market, it can be concluded that cooperatives deal with more disadvantaged farmers at the expense of lower prices. The Paper Four analyses the mechanisms that contribute towards inclusion of disadvantaged households in Zambian maize cooperatives. Inclusion develops in cooperatives that show commitment and either provide financial services to vulnerable members, promote social identities or compensate disadvantaged members for not being able to access subsidised inputs. The overall results show that cooperatives generally work with the most disadvantaged farmers. They create multiple positive effects for their members. However, there is also a meaningful share of cases with a lack of sufficient evidence of effects.

With advanced technology and information explosion, the data of interest often have complex structures, with the large size and dimensions in the form of continuous or discrete features. There is an emerging need for data reduction, efficient modeling, and model inference. For example, data can contain millions of observations with thousands of features. Traditional methods, such as linear regression or LASSO regression, cannot effectively deal with such a large dataset directly. This dissertation aims to develop several techniques to effectively analyze large datasets with complex structures in the observational, experimental and time series data. In Chapter 2, I focus on the data reduction for model estimation of sparse regression. The commonly-used subdata selection method often considers sampling or feature screening. Un- der the case of data with both large number of observation and predictors, we proposed a filtering approach for model estimation (FAME) to reduce both the size of data points and features. The proposed algorithm can be easily extended for data with discrete response or discrete predictors. Through simulations and case studies, the proposed method provides a good performance for parameter estimation with efficient computation. In Chapter 3, I focus on modeling the experimental data with quantitative-sequence (QS) factor. Here the QS factor concerns both quantities and sequence orders of several compo- nents in the experiment. Existing methods usually can only focus on the sequence orders or quantities of the multiple components. To fill this gap, we propose a QS transformation to transform the QS factor to a generalized permutation matrix, and consequently develop a simple Gaussian process approach to model the experimental data with QS factors. In Chapter 4, I focus on forecasting multivariate time series data by leveraging the au- toregression and clustering. Existing time series forecasting method treat each series data independently and ignore their inherent correlation. To fill this gap, I proposed a clustering based on autoregression and control the sparsity of the transition matrix estimation by adap- tive lasso and clustering coefficient. The clustering-based cross prediction can outperforms the conventional time series forecasting methods. Moreover, the the clustering result can also enhance the forecasting accuracy of other forecasting methods. The proposed method can be applied on practical data, such as stock forecasting, topic trend detection. / Doctor of Philosophy / This dissertation focuses on three projects that are related to data reduction and statistical modeling of data with complex structures. In chapter 2, we propose a filtering approach of data for parameter estimation of sparse regression. Given data with thousands of ob- servations and predictors or even more, large storage and computation spaces is need to handle these data. It is challenging to computational power and takes long time in terms of computational cost. So we come up with an algorithm (FAME) that can reduce both the number of observations and predictors. After data reduction, this subdata selected by FAME keeps most information of the original dataset in terms of parameter estimation. Compare with existing methods, the dimension of the subdata generated by the proposed algorithm is smaller while the computational time does not increase. In chapter 3, we use quantitative-sequence (QS) factor to describe experimental data. One simple example of experimental data is milk tea. Adding 1 cup of milk first or adding 2 cup of tea first will influence the flavor. And this case can be extended to cases when there are thousands of ingredients need to be input into the experiment. Then the order and amount of ingredients will generate different experimental results. We use QS factor to describe this kind of order and amount. Then by transforming the QS factor to a matrix containing continuous value and set this matrix as input, we model the experimental results with a simple Gaussian process. In chapter 4, we propose an autoregression-based clustering and forecasting method of multi- variate time series data. Existing research works often treat each time series independently. Our approach incorporates the inherent correlation of data and cluster related series into one group. The forecasting is built based on each cluster and data within one cluster can cross predict each other. One application of this method is on topic trending detection. With thousands of topics, it is unfeasible to apply one model for forecasting all time series. Considering the similarity of trends among related topics, the proposed method can cluster topics based on their similarity, and then perform forecasting in autoregression model based on historical data within each cluster.