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Farmland abandonment in Rio de Janeiro State, Brazil: underlying, proximate causes, and predisposing factors
No full textAlong the RJ-196 road, where imperial palm trees stand near the ruins of old sugar mills and dirty pastures, the landscape tells a story of change: a story of agricultural abandonment. These abandoned sugarcane fields are the focus of this thesis, which explores the issue of land abandonment in Rio de Janeiro. The transformation of these once-thriving agricultural lands into degraded pastures reflects a broader trend with important consequences for food security, the economy, and the environment.
This thesis examines two key aspects: first, it analyzes the agricultural abandonment in Rio de Janeiro through an established theoretical framework in land-use science; second, it engages with existing studies based on this framework to broaden the discussion. The research focuses on three main categories: underlying and proximate causes, predisposing factors of abandonment, and its occurrence in Northern Rio de Janeiro, where the phenomenon is particularly evident.
The study employs several methodologies to map and analyze the temporal and spatial extent of abandoned farmland. These are structured into four steps: (i) a descriptive analysis of cropping trends and spatial patterns, (ii) a larger-scale investigation of underlying causes, (iii) spatial mapping of sugarcane abandonment, and (iv) an analysis of the proximate causes and biophysical predisposing factors contributing to this abandonment. Interrupted Time Series Analysis (ITSA) was used to test the hypothesis that policy changes such as the end of subsidies and the closure of the IAA played a role in the decline of the sugarcane industry and subsequent land abandonment. Additionally, mapping efforts evaluated whether existing datasets accurately represented the timing and extent of farmland abandonment, particularly for sugarcane. Generalized linear models were employed to explore the biophysical predisposing factors and proximate causes driving farmland abandonment in Rio de Janeiro.
The findings reveal that the primary reason for farmland abandonment in Rio de Janeiro is the decline of sugarcane cultivation in the Norte Fluminense region. Key factors include poor infrastructure, lack of irrigation, urban and industrial development, topographic challenges, uneven rainfall, and policy reforms. This research offers critical insights into the causes and extent of agricultural abandonment in Rio de Janeiro State
Arcyriaflavin A as a Potential Therapeutic Agent for Osteoporosis
Get PDFIn this study, Arcyriaflavin A (ArcyA), a natural compound derived from the marine organism Eudistoma sp., was investigated as a potential therapeutic approach for osteoporosis. To evaluate the inhibitory effects of ArcyA on osteoclast differentiation and function, molecular analyses, cellular functional assays, and in vivo experiments in mouse models were performed on both mouse and human cells.
ArcyA significantly reduced the number of TRAP-positive cells at concentrations that were non-toxic to bone marrow-derived macrophages (BMMs). These inhibitory effects were also confirmed in human osteoclasts derived from peripheral blood mononuclear cells (PBMCs).
At the molecular level, ArcyA treatment downregulated key genes associated with osteoclast differentiation (NFATc1, cFos, TNFRSF11α), fusion and survival (DCSTAMP, ATP6v0d2), as well as resorption (CTSK, MMP9, Integrin β3, ACP5). Western blot analyses confirmed these results at the protein level, particularly for NFATc1, cFos, CTSK, and Integrin β3. Moreover, in vitro functional assays indicated that the ArcyA reduced bone-resorptive activity. Furthermore, the results suggested that IκB may serve as a potential target for the inhibitory effect of ArcyA.
In vivo experiments using an ovariectomy (OVX)-induced osteoporosis model demonstrated that ArcyA treatment significantly attenuated bone loss. Treated mice exhibited an increased bone volume-to-tissue volume (BV/TV) ratio in a dose-dependent manner.
In conclusion, ArcyA shows promising therapeutic potential for the treatment of osteoporosis by inhibiting osteoclastogenesis and bone resorption
The role of G-quadruplexes in myeloid dendritic cells
Get PDFDNA can fold into different secondary structures such as G-quadruplexes (G4s). G4s are highly stable and can form in specific guanine-rich regions within DNA and RNA both in vitro and in vivo. Due to their conserved localization within the genome, G4s are suggested to affect different cellular processes, such as DNA replication, gene expression and genome stability. Their formation is cell type specific and dynamically regulated by G4-interacting proteins, cell stages and exogenous stimuli. G4 structures have already been investigated in several cell types, including stem cells and cancer cells, but little is known about G4s in immune cells such as dendritic cells (DCs). DCs are antigen-presenting cells, that link the innate and adaptive immunity by inducing an antigen-specific immune response. Here, we characterise the molecular effects of G4 stabilisation on dendritic cell (DC) phenotype and function using the G4 ligand pyridostatin (PDS). Stabilisation of G4s in bone marrow-derived dendritic cells (BMDCs) induced DC activation and maturation as indicated by elevated levels of co-stimulatory molecules CD40, CD80 and CD86, MHC molecules. G4 stabilisation in DCs also stimulate DC migration, in line with enhanced expression of the chemokine receptor CCR7. Furthermore, coculture experiments revealed that activation of DCs by PDS is enough to trigger the ability of T cell activation, indicated by the upregulation of the specific T cell markers CD69 and CD25 and respective cytokine secretion. Using a B16Ova melanoma model, we show that intratumoral injection of PDS leads to enhanced DC activation within the tumor as well. To further characterise the molecular mechanisms of how G4 formation leads to these cellular changes, we identified proteins that interact with G4s in DCs. Strikingly, among those were STAT3 and STAT1. In subsequent work, we confirmed this interaction and even demonstrated that it binds to a G4 of PD-L1.
With this study, we could show that G4 stabilisation in DCs can be used to affect gene expression of specific genes, leading to enhanced DC activation and functionality
Motivational drivers and the effectiveness of conservation incentives
Get PDFThe debate about how external incentives (e.g., payments for ecosystem services) and internal motivations (e.g., intrinsic values) interact in producing conservation outcomes is still unresolved. This paper examines the role of personal values (biospheric and egoistic) as intrinsic motivational drivers for conservation and their potential to affect conditional payments to enhance conservation behavior. We used a lab-in-the-field experiment with rural farmers in two ecological corridors of Tanzania to assess their conservation behavior under two payment modalities, namely a fixed individual payment and a fixed individual payment with an agglomeration bonus. In addition, a post-experiment survey was conducted to determine the levels of personal value endorsement for each individual participant. We consistently found that biospheric values increased conservation behavior, while egoistic values decreased it. The positive effect of biospheric values was higher than the negative effect of egoistic values. Both payments do not seem to affect the conservation behavior of farmers with high biospheric value endorsement. Heterogeneity in personal values thus likely has economic implications for the design of real-world PES schemes. Our results suggest that educational investments in training future generations of farmers with strong pro-environmental values can reduce future pressure on the environment and the costs of associated policy action. Areas for further research are discussed
Impacts of Supermarkets on Food Consumers and Producers in China
No full textSupermarkets are expanding rapidly in low- and middle-income countries. Compared to traditional food markets, supermarkets are larger, more integrated, and more efficient in procurement and sales. Hence, supermarkets have a more powerful influence on all actors along agri-food value chains. A key question is whether supermarkets are inclusive and beneficial to disadvantaged groups of consumers and producers. This dissertation addresses this knowledge gap through examining the impact of supermarkets on children, women, and smallholder farmers using panel data from China and econometric difference-in-differences techniques.
For consumers, increased supermarket access can improve nutrition. Chapter 2 shows that the nearby establishment of a supermarket increase dietary diversity and nutrient intake among children, with effects being particularly strong in rural areas and low-income households. The key mechanism is that supermarkets improve the availability and affordability of diverse foods. Notably, supermarkets also increase children’s height-for-age, a marker of better long-term nutrition, without increasing weight-for-age or the risk of overweight and obesity.
For women, the expansion of supermarkets alleviates the burden of unpaid work associated with gender-based social norms. Chapter 3 demonstrates that supermarkets offer convenient one-stop shopping and a wide variety of foods, which significantly reduces the time women spend on shopping and cooking. Importantly, these time savings are achieved without harming household dietary quality. In fact, we find positive nutritional effects on those with lower dietary quality. Such time savings also empower women through increasing their participation in paid employment, contributing to greater gender equality.
Supermarket expansion also affects smallholder farmers, though in nuanced ways. Chapter 4 finds positive income effects for remote grain farmers but neutral effects for peri-urban grain farmers. Specifically, supermarkets expand market access for remote farmers, leading to higher farm-gate prices and increased commercialization. Remote farmers also allocate more resources (i.e., land, labor, and purchased inputs) to grain production and finally earn higher income. Meanwhile, peri-urban farmers experience price declines and reduced commercialization due to intensified market competition. However, they adapt by shifting resources to off-farm work to maintain household income.
Overall, the key takeaway of this dissertation is that supermarket-led modernization of agri-food value chains fosters inclusive growth in the context of China: it uplifts disadvantaged consumers and producers without significant negative impacts on nutrition or welfare among other groups.Supermärkte expandieren in Entwicklungsländern rapide. Im Vergleich zu traditionellen Lebensmittelmärkten sind sie größer, stärker integriert und effizienter im Einkauf und in der Vermarktung. Daher haben sie einen stärkeren Einfluss auf alle Akteure entlang der agrarischen Wertschöpfungsketten. Eine zentrale Frage ist, ob Supermärkte inklusiv wirken und benachteiligten Konsumenten und Produzenten zugutekommen. Diese Dissertation adressiert diese Frage. Konkret werden die Auswirkungen von Supermärkten auf Kinder, Frauen und Kleinbauern mithilfe von Paneldaten aus China und ökonometrischen „Difference-in-Differences“ Ansätzen untersucht.
Für Konsumenten, insbesondere Kinder, verbessert ein erhöhter Zugang zu Supermärkten die Ernährung. Kapitel 2 zeigt, dass die Eröffnung von Supermärkten im lokalen Kontext zu einer höheren Ernährungsvielfalt und einer verbesserten Nährstoffaufnahme bei Kindern führt, wobei die positiven Effekte in ländlichen Gebieten und einkommensschwachen Haushalten besonders ausgeprägt sind. Der zentrale Mechanismus besteht darin, dass Supermärkte die Verfügbarkeit und Erschwinglichkeit vielfältiger Lebensmittel verbessern. Bemerkenswert ist zudem, dass Supermärkte das lineare Größenwachstum der Kinder fördern – ein Indikator für verbesserte langfristige Ernährung –, ohne dabei das Risiko von Übergewicht und Adipositas zu erhöhen.
Für Frauen reduziert die Expansion von Supermärkten die Belastung durch unbezahlte Arbeit im Haushalt, die aus geschlechtsspezifischen sozialen Normen resultiert. Kapitel 3 zeigt, dass Supermärkte mit ihrem bequemen “One-Stop-Shopping”-Angebot und ihrer großen Auswahl an Lebensmitteln die Zeit, die Frauen für Einkäufe und Kochen aufwenden müssen, erheblich verringern. Wichtig dabei ist, dass diese Zeitersparnis nicht zu einer Verschlechterung der Ernährungsqualität im Haushalt führt. Vielmehr finden wir positive Ernährungseffekte bei Haushalten, deren Ernährungsqualität zuvor niedrig war. Die eingesparte Zeit stärkt zudem die Position der Frauen, indem sie ihre Teilhabe an bezahlter Beschäftigung erhöht und somit zur Geschlechtergleichstellung beiträgt.
Die Supermarktexpansion wirkt sich auch auf Kleinbauern aus, jedoch auf differenzierte Weise. Kapitel 4 zeigt positive Einkommenseffekte für Getreidebauern in abgelegenen Gebieten, während periurbane Getreidebauern keine wesentlichen Einkommensänderungen erfahren. Supermärkte erweitern den Marktzugang für abgelegene Bauern, was zu höheren Ab-Hof-Preisen und einer verstärkten Kommerzialisierung führt. Ferner investieren abgelegene Bauern mehr Ressourcen (Land, Arbeit und zugekaufte Betriebsmittel) in den Getreideanbau und erzielen dadurch höhere Einkommen. Periurbane Bauern hingegen erleben Preisrückgänge und eine reduzierte Kommerzialisierung aufgrund verstärkten Wettbewerbs am Markt. Sie passen sich jedoch an, indem sie Ressourcen stärker in außerlandwirtschaftliche Tätigkeiten verlagern, um das Haushaltseinkommen aufrechtzuerhalten.
Zusammenfassend lässt sich festhalten, dass die durch Supermärkte vorangetriebene Modernisierung der agrarischen Wertschöpfungsketten inklusives Wachstum fördert: Sie verbessert die Lage benachteiligter Konsumenten und Produzenten, ohne nennenswerte negative Auswirkungen auf Ernährung oder Wohlbefinden anderer Gruppen hervorzurufen
Modeling AMPA receptor trafficking dynamics during long-term potentiation
Get PDFNeurons are excitable cells with a highly complex morphology. Their dendritic arbors stretch across thousands of micrometers and house tiny protrusion-like structures called "Spine," where they receive signals from other neurons. This signal transfer relies on the binding of neurotransmitters released from the presynaptic neuron the receptors localized in the post-synaptic density in the spine head. One of the essential types of receptors is the α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs). They mediate fast-excitatory currents necessary for information transfer from one neuron to another. Given the extensive dendritic structure, localizing AMPARs and modulating their copy numbers at each spine pose a tremendous logistical challenge for the neuron to ensure its function. In this thesis, I aim to provide novel insight into how neurons solve this logistical challenge and how their copy numbers are regulated by synaptic plasticity.
Modern microscopy techniques coupled with advanced labeling methods allow the investigation of molecular composition and visualization of individual molecules in neuronal compartments such as dendrites and spines. However, analyzing this data is a challenging task.
In this thesis, I introduce a novel tool called SpyDen, which I built to efficiently and robustly analyze neuronal imaging data and extract biologically meaningful information from them (discussed in Chapter 2). I discuss the details of my algorithmic solutions to trace dendritic branches and analyze fluorescent puncta like those found in neuronal imaging data. I also provide evidence of thorough validation of the tool to test its efficiency and robustness.
Next, using a combination of mathematical models and experimental data analysis, I investigate the key trafficking steps and their kinetics necessary to explain the experimentally observed distribution of AMPARs and the distinct response of AMPAR subtype to LTP induction (discussed in Chapters 3 and 4). My findings reveal that mRNAs encoding for the AMPAR pore-forming subunits are localized predominantly in the somata. On the other hand, mRNA encoding for one of the most abundant AMPAR auxiliary subunits, CNIH-2, is highly enriched in the dendrites, undergoes local translation, and its rate of synthesis increases following chemical LTP induction. Next, I show that CNIH-2 translation is essential for inserting GluA2-containing AMPAR but not GluA1-homomeric receptors into the neuronal plasma membrane. Furthermore, including this selective trafficking of the AMAPR subtype in my mathematical model, I could accurately recapitulate the distinct temporal profiles of two major AMAPR subtypes: the fast and transient kinetics of calcium-permeable (GluA1-homomeric) AMPAR and the slow and persistent response of GluA2-containing AMPARs to plasticity induction
Deep Learning–Based SD-OCT Layer Segmentation Quantifies Outer Retina Changes in Patients With Biallelic RPE65 Mutations Undergoing Gene Therapy
Get PDFPURPOSE. To quantify outer retina structural changes and define novel biomarkers of inherited retinal degeneration associated with biallelic mutations in RPE65 (RPE65-IRD) in patients before and after subretinal gene augmentation therapy with voretigene neparvovec (Luxturna). METHODS. Application of advanced deep learning for automated retinal layer segmentation, specifically tailored for RPE65-IRD. Quantification of five novel biomarkers for the ellipsoid zone (EZ): thickness, granularity, reflectivity, and intensity. Estimation of the EZarea in single and volume scans was performed with optimized segmentation boundaries. The control group was age similar and without significant refractive error. Spherical equivalent refraction and ocular length were evaluated in all patients. RESULTS. We observed significant differences in the structural analysis of EZ biomarkers in 22 patients with RPE65-IRD compared with 94 healthy controls. Relative EZ intensities were already reduced in pediatric eyes. Reductions of EZ local granularity and EZ thickness were only significant in adult eyes. Distances of the outer plexiform layer, external limiting membrane, and Bruch’s membrane to EZ were reduced at all ages. EZ diameter and area were better preserved in pediatric eyes undergoing therapy with voretigene neparvovec and in patients with a milder phenotype. CONCLUSIONS. Automated quantitative analysis of biomarkers within EZ visualizes distinct structural differences in the outer retina of patients including treatment-related effects. The automated approach using deep learning strategies allows big data analysis for distinct forms of inherited retinal degeneration. Limitations include a small dataset and potential effects on OCT scans from myopia at least −5 diopters, the latter considered nonsignificant for outer retinal layers
Amtliche Bekanntmachungen, 55. Jahrgang, Nr. 66
No full textPrüfungsordnung für den konsekutiven Masterstudiengang „Tierwissenschaften“ der Agrar-, Ernährungs- und Ingenieurwissenschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität Bonn vom 20. August 202
Distributed Decision Models for Structured Data
Get PDFIn recent years, many approaches for producing machine-readable and semantically enriched information on web data, expressed as knowledge graphs, have emerged. Nowadays, scalable analysis of large-scale knowledge graphs for assisting applications in multiple domains is a major challenge for researchers due to the rapid expansion of semantic data on the Web. The primary objective of this thesis is to lay the groundwork for developing efficient algorithms that can perform complex tasks on large-scale OWL datasets, encompassing parsing, exploration, inference of hidden knowledge, and mining of semantic knowledge graphs.
Initially, we proposed an innovative approach for parsing large-scale OWL datasets that can scale horizontally.
In addition, we introduced an innovative approach for conducting statistical computations on large-scale OWL datasets, which calculates 50 different statistical measures about OWL datasets in a distributed in-memory environment. Further, we proposed a scalable, distributed approach for RDFS and OWL reasoning over large-scale OWL datasets. Finally, we developed an innovative decentralized approach to enhance the efficiency of concept learning that is achieved by allowing the generation of terminological decision trees using the statistics of the input dataset.
We conducted several empirical assessments to evaluate the scalability, performance, and efficiency of our proposed approaches. The results of this evaluation showed that the proposed approaches can enable efficient processing and analysis of large-scale OWL datasets. We successfully incorporated all the proposed approaches into the SANSA framework - a big data engine for scalable processing of large-scale RDF data
Randspaltanalyse eines selbstadhäsiven Komposits
Get PDFSelbstadhäsive Komposite wurden entwickelt, um schnell und ohne ein zusätzliches Adhäsivsystem verwendet zu werden. Es stellte sich die Frage, ob das verwendete selbstadhäsive Flow-Komposit (Constic, DMG, Hamburg) eine ausreichende Verbindung mit der Zahnhartsubstanz eingeht. Das Ziel dieser Promotion war es, mithilfe einer Randspaltanalyse zu überprüfen, ob selbstadhäsive Komposite in der Composite-Bonded-to-Flowable-Technik bei Klasse 2 Kavitäten eine suffiziente und zeitsparende Alternative zu konventionellen Materialien sind