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Economy-Wide Effects of Agricultural Value-Chain Enhancement in Agriculture-Based Economies
Get PDFAgrarbasierte Volkswirtschaften in Afrika streben danach, die Produktivität und Produktion gemäß den Empfehlungen der Afrikanischen Union zu steigern. Allerdings kann eine bloße Produktionssteigerung den Landwirten schaden, wenn die Ab-Hof-Preise fallen als die Produktionskosten. Diese Dissertation analysiert die Implikationen der Verbesserung landwirtschaftlicher Wertschöpfungsketten am Beispiel Benin. Eine detaillierte Social Accounting Matrix (SAM) für Benin aus dem Jahr 2019 wird erstellt, die offizielle Statistiken und Stakeholder-Umfragedaten integriert. Diese SAM dient als Grundlage für die Kalibrierung von Computable General Equilibrium (CGE) Modellen, um die gesamtwirtschaftlichen Auswirkungen der Entwicklung landwirtschaftlicher Wertschöpfungsketten zu analysieren. Die Forschung zeigt, dass die Entwicklung des Lebensmittelverarbeitungssektors, beispielhaft durch die Verarbeitung von Cashewkernen und Ananas, positive, armutsreduzierende Wohlfahrtseffekte hat und zum Wirtschaftswachstum beiträgt. Präferenzverschiebungen hin zu heimischem Geflügelfleisch stellen eine Alternative zu Handelspolitiken dar, um den heimischen Sektor zu stärken. Die Verarbeitung von Cashew-Nebenprodukten birgt Potenzial für die wirtschaftliche, soziale und ökologische Nachhaltigkeit der Agrar- und Ernährungssysteme. Investitionen in eine stabile Strominfrastruktur zur Unterstützung des industriellen Wachstums können die Produktionskosten senken und die Nachfrage nach landwirtschaftlichen Produkten erhöhen, was insbesondere einkommensschwachen Haushalten zugutekommt.
Insgesamt kommt die Studie zu dem Schluss, dass die Entwicklung landwirtschaftlicher Wertschöpfungsketten in agrarwirtschaftlich geprägten Volkswirtschaften das Haushaltseinkommen erhöht, die Armut verringert, die makroökonomischen Indikatoren verbessert und die allgemeine wirtschaftliche Entwicklung fördert.Agriculture-based economies in Africa are striving to boost productivity and production following the African Union's recommendations. However, merely increasing production can harm farmers if farm-gate prices drop more than production costs. Research on the broader economic effects of agricultural value-chain development is limited. This thesis addresses this gap by examining the economy-wide implications of enhancing agricultural value-chains, using Benin as a case study. A detailed 2019 Social Accounting Matrix (SAM) for Benin is constructed, incorporating official statistics and stakeholder survey data. This SAM is used as the basis for calibrating Computable General Equilibrium (CGE) models. These models were adapted to analyze the impact of developing the food-processing sector, preference shifts, and stable electricity supply on the economy. The research reveals that developing the food-processing sector, exemplified by cashew nut and pineapple processing, has positive, pro-poor welfare effects and contributes to economic growth. Preference shifts towards domestic poultry meat is an alternative to trade policies in boosting the domestic sector. Processing of cashew byproducts has potential for economic, social and environmental sustainability of the agri-food systems. Investing in stable electricity infrastructure to support industrial growth can reduce production costs and increase demand for agricultural products, benefiting low-income households disproportionately. Overall, the study concludes that developing agricultural value-chains in agriculture-based economies enhances household income, reduces poverty, improves macroeconomic indicators, and fosters overall economic development
Three Essays on Unconventional Monetary Policy, Credit Supply and Investment
Get PDFDiese Dissertation umfasst drei Aufsätze, die untersuchen, wie sich Veränderungen im Kreditangebot auf Investitionen auswirken. Ein besonderes Augenmerk liegt hierbei auf der Relevanz von Firmenheterogenität und Finanzfriktionen. Der erste Aufsatz untersucht die Rolle von Heterogenität im Kreditausfallrisiko verschiedener Unternehmen für die Transmissionsmechanismen unkonventioneller Geldpolitik. Hierbei geht es insbesondere um Politikmaßnahmen, welche das Kreditangebot erhöhen (sogenannte Credit Policy). Die Analyse basiert auf einem Neukeynesianischen Modell mit zwei Agenten. Im Vergleich zu einem Modell mit einem einzigen repräsentativen Unternehmen, ist die Effektivität von Credit Policy in diesem Modell geringer. Darüber hinaus ist Credit Policy am effektivsten, wenn sie auf jene Unternehmen abzielt, die vergleichsweise schwach von Kreditbeschränkungen betroffen sind. Der zweite Aufsatz beinhaltet eine detaillierte empirische Analyse der Auswirkungen von Kreditangebotsschocks auf der Unternehmensebene. Im Rahmen sogenannter Panel-Local-Projections wird gezeigt, dass Unternehmen unterschiedlich und asymmetrisch auf solche Schocks reagieren. Die Asymmetrie in den Reaktionen der Unternehmen lässt sich nicht auf Zweitrundeneffekte über Kreditbeschränkungen zurückführen. Im dritten Aufsatz wird ein partielles Gleichgewichtsmodell entworfen, um diese empirischen Resultate zu erklären. In diesem Modell führen zeitweise bindende Beschränkungen von Finanzintermediären zu Asymmetrie in den Auswirkungen von Kreditangebotsschocks. Die Interpretation der empirischen Resultate im Rahmen dieses theoretischen Modells deutet darauf hin, dass Beschränkungen von Finanzintermediären entscheidend für die Effekte von Kreditangebotsschocks sind. Dies ist relevant für die gesamtwirtschaftlichen Auswirkungen und die Verteilungswirkung von Credit Policy.This thesis contains three essays, which study the transmission of changes in credit supply to investment, focusing on the role of firm heterogeneity and financial frictions. The first essay theoretically investigates the role of default risk heterogeneity for the transmission of unconventional monetary policy. Specifically, I consider the effects of policies expanding the supply of credit (credit policy) in the context of a Two-Agent New-Keynesian model with financial frictions. In this model with firm heterogeneity, the effectiveness of credit policy is reduced compared to a representative firm model. Moreover, credit policy is most effective when targeted at firms that are relatively less affected by financial constraints. The second essay features a detailed empirical analysis of the firm-level effects of credit supply shocks. Using a panel local-projections analysis, I show that there is pronounced heterogeneity and asymmetry in the investment effects of these shocks. I also document that asymmetry in investment responses is not driven by differences in the strength of second round amplification effects via firm-level borrowing constraints. In the third essay, I construct a partial equilibrium model to rationalize these empirical findings. In this model, occasionally binding constraints of financial intermediaries give rise to asymmetry in the effects of credit supply shocks. Interpreted in the context of the partial equilibrium model, my empirical findings indicate that constraints of financial intermediaries are crucial for the transmission of credit supply shocks. This may have implications for the aggregate and distributional consequences of credit policy
Reducing neuroendocrine psychosocial stress response through socio-emotional dyadic but not mindfulness online training
Get PDFIntroduction: Stress-related diseases pose significant health risks and show wide prevalence. Empirical evidence suggests that contemplative practices, such as socio-emotional dyadic mental exercises, hold promise in mitigating the adverse effects of stress and promoting psychosocial well-being. This study aimed to investigate the differential effects of two online contemplative mental training programs on the psychosocial stress response: the first involved classic mindfulness practices, while the second incorporated a socio-emotional dyadic approach known as Affect Dyad.
Methods: The study was conducted as part of the longitudinal CovSocial project’s phase 2 in the context of the COVID-19 pandemic. 140 individuals participated in the Trier Social Stress Task (TSST), where the psychosocial stress response was assessed with cortisol saliva samples and subjective stress questionnaires in a cross-sectional design after the active training groups finished their intervention period. Participants were randomly assigned to the socio-emotional training group, mindfulness-based training group, or a control group that did not receive any training. Both training programs consisted of a ten-week intervention period with a daily 12-minute app-based mental training practice and weekly 2-hour online coaching sessions led by mental training teachers.
Results: Results showed that the socio-emotional Dyad group but not the mindfulness-based group exhibited significantly lower cortisol levels at 10, 20, 30, and 40 minutes after the stressor as well as lower total cortisol output compared to the control group during the TSST, indicating a reduced hormonal stress response to a social stressor. Subjective markers did not show differences between the three groups.
Discussion: These findings indicate that the daily socio-emotional dyadic practice, which emphasizes non-judgmental and empathic listening as well as the acceptance of challenging emotions in the presence of others within one's daily life context, may serve as a protective factor against the adverse effects of psychosocial stress triggered by the fear of negative social judgments. Given the high prevalence of stress-related diseases, such online mental training programs based on dyadic practices may thus represent an efficient and scalable approach for stress reduction.Peer Reviewe
Analysis of Biotic and Abiotic Factors on the Life History Traits of Anopheles Mosquitoes
No full textEiner der ausschlaggebenden Faktoren für das Übertragungspotenzial von Malaria ist die Häufigkeit ihres Überträgers, der Anopheles-Mücke. Da diese Insekten besonders empfindlich auf ihre Umgebung reagieren, wurde in vielen Laborexperimenten das Verhältnis zwischen Umweltfaktoren und Malaria untersucht. In natürlichen Umgebungen ist über diesen Zusammenhang wenig bekannt.
Untersuchungsgegenstand dieser Arbeit mit multidisziplinärem Ansatz ist die Beziehung zwischen verschiedenen Umwelteinflüssen und der Häufigkeit von Anopheles-Mücken in natürlicher Umgebung sowie die möglichen diesem Prozess zugrundeliegenden Mechanismen. Zunächst lässt sich anhand von Feldstudien und empirischen dynamischen Modellen eine verzögerte Auswirkung der Umwelt auf die Mückenhäufigkeit feststellen, was wiederum einen Einfluss auf die Entwicklung der Larvenstadien bedeuten könnte. Im Anschluss werden mögliche Hintergründe untersucht mit Hilfe eines kontrollierten Versuchsaufbaus, in dem Anopheles-coluzzii-Larven und Erwachsenentiere auf Umweltbedingungen reagieren. Dabei lässt sich feststellen, dass Temperatur und Besatzdichte vielschichtige Auswirkungen auf Larvenentwicklung und -sterblichkeit haben. Darüber hinaus gibt es Übertragungseffekte auf die Alterung und Fruchtbarkeit der Erwachsenentiere. Abschließend zeigt sich durch die Entwicklung eines vollständigen Modells für den Lebenszyklus von Anopheles-Mücken, dass die ermittelten Umwelteinflüsse auf Larven und erwachsene Mücken einen komplexen Einfluss auf die Größe der Mückenpopulation haben.
Anhand mehrere mathematischer Methoden werden in dieser Arbeit Informationen aus Feldsammlungen und Versuchsdaten erfolgreich kombiniert. Dies unterstreicht die Bedeutung multidisziplinärer Ansätze für das Verständnis der komplexen Dynamik zwischen Mücken und der Umwelt. So entsteht ein detailliertes Bild der Lebensmerkmale der Mücken, die von der Umwelt beeinflusst werden, und deren Auswirkungen auf die Populationsdynamik.One of the main determinants of malaria transmission is the abundance of its vector, the Anopheles mosquito. As these insects are susceptible to the environment in which they live, many laboratory experiments have explored the connection between environmental factors and the abundance of mosquitoes. However, little is known about this relationship in natural settings.
In this work, I used a multidisciplinary approach to determine the relationship between environmental drivers and Anopheles abundance and the possible mechanisms that characterise these relationships. First, using field study data and an empirical dynamic modelling approach, I identified a delayed effect of the environment on mosquito abundance, suggesting an impact on the development of larval stages. Second, I explored the possible mechanisms behind this process using a controlled experimental setup in which Anopheles coluzzii larvae and adults responded to the environmental conditions. I identified a complex response to temperature and rearing density of larval development and mortality, as well as carry-over effects on adult ageing and fecundity. Finally, by developing a full model for the life cycle of Anopheles mosquitoes, I determined that the identified environmental impacts on larvae and adult mosquitoes have a complex impact on the mosquito population size.
Taken together, this work combined the information from field collections and experimental data successfully using multiple mathematical methods, highlighting the importance of multidisciplinary approaches in understanding the complex dynamics between mosquitoes and the environment. With this approach, we obtained a detailed picture of the mosquito life traits that are impacted by the environment and its effects on mosquito population dynamics
Chemically accurate predictions for water adsorption on Brønsted sites of zeolite H-MFI
Get PDFWe investigate the adsorption of water molecules in the zeolite H-MFI at isolated Brønsted acid sites (BAS) for loadings of 1, 2, and 3 H2O/BAS. We consider two approaches to the O3Al–O(H)–Si sites: the Brønsted-type approach of H2O to the acidic proton and the Lewis-type approach to the aluminium atom of the AlO4 tetrahedron. From the twelve crystallographically inequivalent framework sites for Al, a representative set of six active site positions is chosen. For them, we calculate CCSD(T)-quality adsorption energies at MP2-quality adsorption structures for different approaches, 48 in total. The Brønsted-type approach is favoured for most cases but the Lewis-type approach has similar stability for some framework positions. We predict heats of adsorption per molecule ranging from 60 to 76, 56 to 65, and 56 to 64 kJ mol−1 for loadings of 1, 2, and 3 H2O/BAS, respectively. For 1 H2O/BAS, the experimental result (70 kJ mol−1) falls into the range of our predictions, whereas for 2 and 3 H2O/BAS, the measured adsorption heats per molecule (74 and 70 kJ mol−1, respectively) are larger than our predictions. For 2 H2O/BAS, the ion-pair structure generated by proton transfer to the water dimer competes with the neutral adsorption complex. The DFT adsorption energies (PBE+D2) deviate significantly from the CCSD(T)-quality reference energies, by up to 25 kJ mol−1 for 1 H2O/BAS, 25 kJ mol−1 per H2O for 2 H2O/BAS, and 18 kJ mol−1 per H2O for 3 H2O/BAS. Specifically, PBE+D2 overstabilises the ion-pair structure, i.e. in many cases the PBE+D2 error is much larger for ionic than for neutral adsorption structures.Norddeutscher Verbund für Hoch- und Höchstleistungsrechnen 10.13039/100030685Deutsche Forschungsgemeinschaft 10.13039/501100001659Peer Reviewe
Determinants of changes in harvested area and yields of major crops in China
Get PDFGlobal agricultural production has risen substantially in recent decades and needs to rise further to meet the ever-growing food demand. While higher production can be directly attributed to agricultural expansion and intensification, the underlying factors behind the changes in cultivated areas and yields can be complicated and have not been well understood. China has dramatically increased its food production in past decades, especially during the initial approximately 30 years following the commencement of the rural reform in the late 1970s. The agricultural land use, including cropland areas, the composition of different crops and their spatial distributions, and crop yields have experienced substantial changes. In this research, we quantitatively analysed the changes in the harvested areas and yields of the four most widely cultivated crops in China (rice, wheat, maize, and soybean) at the county level from 1980 to 2011. We used spatial panel regressions to quantify the determinants of the observed changes in harvested area and yields for the major cultivation region of each of the four crops. Results showed that growth in population, gross domestic product, and urbanisation are positively associated with harvested areas. Higher usage of machinery and fertiliser inputs increased yields of the three cereal crops, while the harvested area of soybean decreased, particularly after China’s accession to the WTO. Our findings reveal how domestic urbanisation and changes in consumption patterns, coupled with the rising globalisation of agricultural markets, shaped China’s agricultural production and land use over the three decades. These insights shed light on the determinants of long-term agricultural dynamics and thus inform evidence-based decision-making.Peer Reviewe
Correction: El-Harairy et al. Aphid-Ant Relationships: The Role of Cuticular Hydrocarbons and Different Chemical Stimuli in Triggering Mutualistic Behavior. Agriculture 2024, 14, 529
Get PDFA corrected version of this publication is available at: https://doi.org/10.18452/30206Peer Reviewe
On the origins of national identity. German nation-building after Napoleon☆
No full textWhat are the origins of national identity? We investigate the success of propaganda as one the first nation-building policies conducted in the German lands around 1815. To elicit identity changes at the level of individuals we use data on first names across German cities and villages. To validate the approach of using first names, we show that soldiers with national names had a higher likelihood to be honored for bravery during the German-French War. Exploiting unanticipated border changes together with variation within the same families over time, i.e., family fixed effects, we find that parents in treated cities responded by choosing national (rather than ruler) first names for their children. We do not find a corresponding increase in villages suggesting that national identity was more prevalent among the urban population, in particular the elite, during this period.Peer Reviewe
Data repository for submitting "Terrylene on monolayer WS2: coverage-dependent molecular re-orientation and interfacial electronic energy levels" to "Mater. Adv."
No full textThis repository contains the original experimental data plotted in the paper titled "Terrylene on monolayer WS2: coverage-dependent molecular re-orientation and interfacial electronic energy levels" submitted to the journal Materials Advances.Dieses Repository enthält die ursprünglichen experimentellen Daten, die in dem Artikel mit dem Titel „Terrylene on monolayer WS2: coverage-dependent molecular re-orientation and interfacial electronic energy levels“ aufgezeichnet wurden, der bei der Zeitschrift Materials Advances eingereicht wurde. Der Datensatz enthält alle relevanten Roh- und verarbeiteten Daten, die den im Artikel vorgestellten Erkenntnissen zugrunde liegen.This repository contains the original experimental data plotted in the paper titled "Terrylene on monolayer WS2: coverage-dependent molecular re-orientation and interfacial electronic energy levels" submitted to the journal Materials Advances. The dataset includes all relevant raw and processed data that underpin the findings presented in the paper
