Fakultät Agrarwissenschaften

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https://hohpublica.uni-hohenheim.de/handle/123456789/9

Die Fakultät entwickelt in Lehre und Forschung nachhaltige Produktionstechniken der Agrar- und Ernährungswirtschaft. Sie erarbeitet Beiträge für den ländlichen Raum und zum Verbraucher-, Tier- und Umweltschutz.

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A 2004 social accounting matrix for Israel : documentation of an economy-wide database with a focus on agriculture, the labour market, and income distribution
(2011) Siddig, Khalid; Flaig, Dorothee; Luckmann, Jonas; Grethe, Harald
This document describes the Israeli Social Accounting Matrix (SAM) for the year 2004, developed by the Agricultural and Food Policy Group at the University of Hohenheim. The SAM is a part of a larger research project which aims to analyse several economic, trade, and labour policies in the context of economic integration of agriculture between Israel and the West Bank. Data are obtained from various sources in Israel. Sources include the Israeli Central Bureau of Statistics (ICBS), the Central Bank of Israel (CBI), and the Israeli Tax Authority (ITA). Data from sources outside of Israel are used to fill-in some gaps in the domestic reports. External sources include the World Trade Organization (WTO), the Organisation for Economic Co-operation and Development (OECD), and the World Bank. The SAM provides data on 47 sectors with activities separated from commodities, 36 labour force types, 10 household groups, as well as 17 tax accounts in addition to 37 accounts reserved for taxes on production factors. A topdown approach is pursued by first building a balanced macro SAM which is consistent with 2004 national account data. Subsequently, the macro SAM is disaggregated into a micro SAM which is balanced in several steps.
A utility function based approach towards the modeling of migration in village equilibrium models
(2010) Kleinwechter, Ulrich
Village equilibrium models are computable general equilibrium (CGE) implementations of agricultural household models in a village equilibrium framework which have the salient feature of being able to capture general equilibrium effects arising at the level of rural communities. Due to the important role migration plays for livelihoods in developing countries, the approach has been successfully applied to analyze aspects related to migration and village economies. However, the depiction of migration in village equilibrium models is not carried out in a way that captures interactions between migration and household consumption demand while at the same time allows for an endogenous adjustment of the level of migration by the households themselves. Furthermore, approaches to modeling migration are purely demand side oriented. Supply side factors, such as differences between households, which may influence household responses to changes in incentives to migrate, cannot be accommodated in a theoretically convincing manner. To address these issues, a nonseparable household model with endogenous migration decisions and feedback to the consumption sphere is proposed as the theoretical foundation for a village equilibrium model. A composite utility function captures utility which accrues to the household through per capita household consumption of goods and leisure, on the one hand, and utility stemming directly from participation in different activities by the household including migration, on the other hand. It is shown that the allocation of labor among different activities is governed by the size of marginal returns to labor in terms of market returns, changes in household demand and (dis)utility of labor market participation relative to the household shadow wage. The practical implementation of the theoretical framework is achieved by the derivation of two independent demand systems from the composite utility function. A per capita linear expenditure system is proposed to depict household consumption demand. The allocation of labor to migration is assumed to follow a factor demand specification using power functions which translate utility considerations made by the household into imperfectly elastic responses to changes in incentives for participation in the labor market.
Agrivoltaics: The environmental impacts of combining food crop cultivation and solar energy generation
(2023) Wagner, Moritz; Lask, Jan; Kiesel, Andreas; Lewandowski, Iris; Weselek, Axel; Högy, Petra; Trommsdorff, Max; Schnaiker, Marc-André; Bauerle, Andrea
The demand for food and renewable energy is increasing significantly, whereas the availability of land for agricultural use is declining. Agrivoltaic systems (AVS), which combine agricultural production with solar energy generation on the same area, are a promising opportunity with the potential to satisfy this demand while avoiding land-use conflicts. In the current study, a Consequential Life-Cycle Assessment (CLCA) was conducted to holistically assess the environmental consequences arising from a shift from single-use agriculture to AVS in Germany. The results of the study show that the environmental consequences of the installation of overhead AVS on agricultural land are positive and reduce the impacts in 15 of the 16 analysed impact categories especially for climate change, eutrophication and fossil resource use, as well as in the single score assessment, mainly due to the substitution of the marginal energy mix. It was demonstrated that, under certain conditions, AVS can contribute to the extension of renewable energy production resources without reducing food production resources. These include maintaining the agricultural yields underneath the photovoltaic (PV) modules, seeking synergies between solar energy generation and crop production and minimising the loss of good agricultural land.
Broiler production in Ghana and Senegal : farm economics, international competitiveness and policy considerations
(2023) Chibanda, Craig Chikomborero; Wieck, Christine
Chicken meat consumption has rapidly increased in many West African countries in the last three decades. The increase in consumption has been attributed to several factors, which include population growth, urbanization, rising incomes, and the nutritional importance of chicken meat. However, poultry producers in many West African countries were struggling to meet the rising demand. Consequently, the gap in supply and demand led to an increase in frozen poultry meat imports by many African countries at the end of the 1990s. Most of the imports consisted of chicken meat cuts, which were considerably cheaper than domestically produced chicken meat. Price-wise, domestic chicken meat could not compete with imports, which sparked debate over their importation. In West African nations such as Ghana, Senegal, and Ivory Coast, farm closures, income losses, and a precipitous decline in domestic poultry production are believed to have resulted from the imports' low prices. In the early 2000s, countries in the region reacted differently to the influx of low-priced chicken imports, with some countries instituting protectionist measures that halted the imports while others continued to import the low-priced frozen chicken meat as a means of providing their citizens with a source of affordable animal protein. Although there has been much debate about the various pathways that countries have taken, limited research has been conducted to compare the agronomic and economic status quo of broiler chicken production in countries with different policies. Against this backdrop, the overarching objective of this dissertation is to investigate the economics and international competitiveness of broiler production in two West African countries pursuing different poultry trade policies: Ghana (which is heavily reliant on chicken meat imports) and Senegal (which banned poultry meat imports for almost two decades). Five research gaps in the body of literature on broiler production in Ghana and Senegal are identified in this dissertation. First, existing studies classify broiler production in Ghana and Senegal into broad production systems that are ambiguous. Second, although a number of studies have been conducted on the Ghanaian broiler value chain, there are conflicting arguments regarding the reasons for its lack of development. Third, existing studies do not provide comprehensive analyses of the performance (management), cost structure, and profitability of different broiler farm types in Ghana and Senegal. Fourth, there are no existing studies that compare the international competitiveness of broiler farms in West African countries like Ghana and Senegal with those in key chicken meat exporting countries. Fifth, the current body of literature fails to adequately examine some policy-related concerns. Specifically, little consideration is given to the potential effects of implementing alternative poultry trade policies in Ghana on producers. Based on these research gaps, this dissertation attempts to answer three overarching research questions: i. What is the state of broiler farm economics and broiler value chains in Ghana and Senegal? ii. How does the competitiveness of broiler farms in Ghana and Senegal compare with those in key chicken meat exporting countries in Europe (i.e., Germany and the Netherlands)? iii. What are the potential effects of implementing alternative poultry trade policies in Ghana? As this is a cumulative dissertation, the research questions were addressed in a series of journal articles that are included in this dissertation as chapters 2, 3, 4, 5, and 6. Chapter 2 characterizes and analyses the economics of broiler production systems in Ghana. The typical farm approach is used for this purpose. This approach entails constructing empirically grounded farm data sets that are called “typical farms” through the use of a multi-stakeholder workshop, semi-structured interviews, and focus groups. Three broiler production systems in three regions were identified. They include the large-scale integrated production system (> 20,000 birds/year) in the Ashanti (Kumasi) region, the medium-scale system (5,000–20,000 birds/year) in the Brong-Ahafo (Dormaa) region, and the small-scale commercial system (< 5,000 birds/year) in the Greater Accra region. The Technology Impact Policy Impact Calculations (TIPI-CAL) model was then used to determine the performance, costs of production, and profitability of typical farms. TIPI-CAL is a production and accounting model used for farm economic analysis as it allows a detailed examination of farm-level variables and simulations. The findings presented in Chapter 2 show that the typical small-scale farm is performing the least in comparison to the other farm types in the country in terms of feed conversion ratios (FCR) and Broiler farm economy index (BFEI). The low farm performance of the typical small-scale farm is attributed to the use of poor-quality feed, inappropriate husbandry practices, and its long feeding period. Small-scale producers in Ghana attribute the unusually long feeding period (around 63 days) to market competition from low-priced frozen chicken meat imports. The producers explained that instead of selling their chickens in 42 days they had to rear them for up to 63 days because there is no ready market for them. The findings also show that although the typical medium-scale and large-scale integrated farms are generally performing better than the small-scale farm, they are also not performing so well in terms of the expected performance levels. Furthermore, the results show that broiler production in Ghana is typically seasonal. The seasonal production was attributed to the competition from frozen chicken meat imports, which are cheaper and more readily available in cut pieces, making preparation easier than with domestic chickens that are typically sold live. The results of the farm economic analysis also show that feed and day-old chick (DOC) costs are the most significant production cost items for all three typical farms. Despite the relatively high costs of feed and DOCs, broiler production as a seasonal activity is profitable for all typical farms. Chapter 3 studies the performance of Ghana’s poultry value chain and examines the interlinked challenges that actors in the value chain are facing and their underlying causes. The Sustainable Food Value Chain (SFVC) framework is used to assess and develop strategies to sustainably upgrade the Ghanaian broiler value chain. The SFVC concept moves away from the traditional approach of value chain analysis, where well-known constraints are listed along with proposed recommendations. Instead, the concept takes a universal perspective to identify the interlinked foundational causes of why value chain actors fail to take advantage of existing end-market opportunities. Due to the complex nature of studying value chains, both qualitative and quantitative research methods are employed. These include focus groups, semi-structured interviews, desk reviews, and the Delphi method. The results of the study highlight the poor economic, social, and environmental performance of the Ghanaian poultry sector. Although the results of the Delphi study show that poultry experts in Ghana perceive imports and high feed costs as the most significant challenges facing the value chain, a deeper analysis reveals that weak vertical and horizontal coordination among actors in the value chain, coupled with low commitment from supporting stakeholders, emerge as the root causes of the value chain's challenges. To achieve sustainable growth, the Ghanaian poultry value chain requires commitment and support from the government and other stakeholders, as well as coordination between them. The study also explains that effective vertical relationships (e.g., trust and communication) will play a vital role in the process of upgrading the value chain by promoting conditions that encourage investment. Also, effective cooperation in the horizontal linkages, for example, among producer associations (especially for the many small-scale producers), would contribute to reducing their production costs while facilitating their access to buyers and processors. In addition, competitive improvements would result in more value-added domestic chicken products that cater to the growing demands of Ghanaian consumers at lower prices. Chapter 4 studies the state of broiler production in Senegal after nearly two decades of poultry import restrictions. It provides a synopsis of the Senegalese broiler value chain and evaluates the performance and economics of different farm types. A multi-stakeholder workshop and interviews were conducted with key informants to investigate the structure and activities of the Senegalese broiler value chain. Again, the typical farm approach was used to construct and analyze typical farms that represent the most common broiler production systems in Senegal. Small-scale (<10.000 birds/year), medium scale (10,000–100,000 birds/year), and large-scale integrated (> 100,000 birds/year) production systems were identified as the most prevalent broiler production systems. The findings show that the two typical medium-scale broiler farms in Senegal are performing well in terms of FCRs, BFEI, and mortality rates. The good performance is attributed to the use of high-quality inputs (feed and chicks) and good husbandry practices. The results of the value chain analysis suggest that the country has well-developed feed and hatchery industries. Therefore, the development of these industries has ensured that producers have access to domestically produced, high-quality inputs. Nevertheless, the typical small-scale farm is not performing well, and this is attributed to inappropriate poultry husbandry practices. Additionally, the analysis revealed that feed and day-old chick (DOC) costs are the most significant in conventional broiler production in Senegal. Despite the high costs of feed and DOCs, broiler production is profitable for all typical farms. Chapter 5 examines whether differences in the competitiveness of broiler farms in Ghana, Senegal, Germany, and the Netherlands provide insight into why domestically produced chicken meat in West African countries is more expensive than imports from Europe. For this comparison, farm management (none monetary farm performance indicators) and economic performance indicators (costs of production and profitability) of typical broiler farms in the four countries are derived. The study shows that most of the typical broiler farms in Ghana and Senegal are not competitive with farms in Germany and the Netherlands in terms of farm management. More specifically, the findings show that the typical German and Dutch broiler farms are performing better than all typical farms in Ghana and the typical small-scale farm in Senegal in terms of the FCRs, BFEI, mortality rates, and number of production cycles per year. However, the performance of typical medium scale farms in Senegal is almost comparable to that of German and Dutch farms in terms of all the farm management indicators that were analyzed. The good farm management of medium scale farms in Senegal is attributed to good animal husbandry practices and the use of high-quality feed and high-quality DOCs. The findings also show that typical broiler farms in Ghana and Senegal are not competitive with German and Dutch farms in terms of economic performance. The poor economic performance of the Ghanaian and Senegalese farms is attributed to higher production costs. Apparently, the broiler farms in the two countries have higher production costs due to high feed and DOC costs. In Ghana, high feed costs are attributed to high feed prices and feed-use inefficiency (reflected by high FCRs). In the case of Senegal, high feed costs are largely due to high feed prices. Having established that typical broiler farms in Ghana and Senegal are not competitive in terms of farm management and costs of production , the impact of improving farm management (primarily the FCRs) on production costs was then simulated using the TIPI-CAL model. The results of the simulations demonstrate that improving farm management to optimum levels would lead to a reduction in the costs of production for Ghanaian and Senegalese farms. However, the reduction would not be sufficient to make the farms competitive with those in Germany and the Netherlands because high input costs (feed and DOC) are the primary contributors to high production costs. Improving the competitiveness of broiler farms will therefore require a combination of interventions designed to lower input costs and enhance farm management. For decades, Ghanaian policymakers have been pressured to implement protectionist policies to protect the poultry value chain from low-priced imports. Chapter 6 examines the potential impact of implementing these policies. The Modular Applied General Equilibrium Tool (MAGNET) and TIPI-CAL models are used to examine the: (1) potential impact of a hypothetical complete ban of poultry meat imports in Ghana; (2) potential impact of a partial ban of poultry products (banning poultry products originating from the UK, Germany, the Netherlands, Denmark, and Russia); (3) potential effects of raising the import tariffs on poultry meat in Ghana to 40 percent and 99 percent; and (4) potential effects of abolishing the current 5% import tariff rate on maize imports. The results show that a complete ban on poultry meat imports would have a positive impact on domestic poultry meat production, increasing production by 254%. This increase will be most likely driven by existing farms doubling their production cycles and new producers attracted to a protected broiler sector. The findings also show that a complete ban would increase the importation of maize. Considering the importance of maize for poultry production in Ghana, the effects of abolishing the existing 5% import tariff rate on maize were simulated. The results show that removing the tariff would not lead to a significant increase in poultry production. This is most likely due to the fact that the tariff rate is already very low. In accordance with World Trade Organization (WTO) agreements, Ghana is allowed to increase the tariff rate on poultry meat up to 99% (the maximum level of bound tariff). The findings show that increasing the tariff rate from the current 35% to 99% would result in a 104% increase in domestic poultry meat production. The tariff would offer significant protection to domestic producers and result in a significant reduction in poultry meat imports (around 57% reduction in imports). The typical farm analysis indicates that broiler farms in Ghana are more prevalent in urban and peri-urban areas. Therefore, a boost in domestic poultry meat production would most likely lead to an increase in urban and peri-urban employment. The findings also show that medium- and large-scale farms employ the highest number of people; therefore, such farm types are expected to boost urban and peri-urban employment if they increase production. Also, of importance, an increase in domestic broiler production will most likely have positive knock-on effects on other value chain actors such as slaughterhouses, feed millers, and poultry traders. Although the results indicate that producers will benefit from the implementation of protectionist measures, it is important for policymakers to keep in mind that such measures will most likely also have negative implications. For example, the results show that protectionist measures would lead to a decrease in the Gross domestic product (GDP) as the measures would either reduce or eliminate the imports leading to reduced tariff revenues, which account for a large share of total tariff revenues in Ghana. The dissertation concludes that a comprehensive sector-wide policy-making approach that considers all the challenges facing the different value chain actors (e.g., hatcheries, feed millers, producers, traders, slaughterhouses and consumers) will be more effective in providing a delicate balance that ensures that the broiler value chains in Ghana and Senegal develop and consumers have access to affordable chicken meat. Such an approach would also be useful in addressing the issue of high input prices (mainly feed and day-old chicks), which is at the center of the low competitiveness of broiler farms in the two countries. Additionally, the comprehensive policy-making approach should also consider the need for proper infrastructure and technology to support the growth of broiler value chains. This includes investments in cold storage facilities and slaughterhouses to ensure efficient and cost-effective processing and distribution of chicken meat. By addressing these challenges holistically, policymakers can create an enabling environment for the development of sustainable and competitive broiler value chains in both countries.
Changing conditions for local food actors to operate towards agroecology during the COVID-19 pandemic
(2022) Frank, Markus; Kaufmann, Brigitte; Ejarque, Mercedes; Lamaison, María Guadalupe; Nessi, María Virginia; Amoroso, Mariano Martin
Given the novel character of disturbances caused by the pandemic in food systems, initial studies have been conducted to stress the reinforced urgent need for food systems' transformation toward sustainability. First assessments, conducted in the early months of the pandemic, found that local food actors responded to changing production and marketing conditions by implementing alternative practices under the umbrella of agroecology. However, given the unprecedented and dynamic character of the pandemic in regional situations, and related context-specific changes caused in food system actors' operations, case studies are needed to assess in more detail under which changing conditions food actors implemented alternative practices. Moreover, the maintenance of practices as conditions normalize, and food actors' transformative potential in relation to the principles of agroecology, need further assessment. In response to these emerging issues, we provide insights into our case study research conducted during 2021 in a local food system in Argentina. The aim of this research was to study how changing conditions triggered local food actors to (re-)frame their objectives and activities regarding marketing, and to assess the relevance of agroecological principles as a means of responding to changing conditions and to unfold longer-term transitions. We identified local producer shops (n = 5) and markets (n = 4) that were established or consolidated by self-organized producer groups (SOPGs) during the first months of the pandemic. Using semi-structured interviews with SOPG members (n = 12) and qualitative content analysis, we found that alternative practices were adopted in response to different changing conditions, and new needs and opportunities for producers and consumers brought about by the pandemic. Objectives pursued, and activities undertaken by the groups revealed reactive short-term mitigation strategies, and proactive longer-term transformative objectives. The relational analysis between practices and agroecological principles showed that the principles became important means of responding to changing conditions and to unfold longer-term transitions. The cases illustrate how local food actors operationalized agroecological principles, and in turn how principles can be used to investigate the nature and potentials of food actors' alternative practices, highlighting the relevance of agroecology to co-design sustainability transitions in local food systems and to mitigate possible future crisis.
Climate‐based identification of suitable cropping areas for giant reed and reed canary grass on marginal land in Central and Southern Europe under climate change
(2023) Ferdini, Sofia; von Cossel, Moritz; Wulfmeyer, Volker; Warrach‐Sagi, Kirsten
Giant reed (GR) and reed canary grass (RCG) have emerged as promising perennial industrial crops for providing sustainable bioenergy from marginal land. However, there is great uncertainty among farmers and researchers about where these crops can be grown in the future due to climate change, which complicates a timely transition to a bioeconomy. Therefore, this study quantifies marginal land and suitable cropping areas for GR and RCG in Europe, as well as their overlap. To derive these areas, the present (1991–2020) and future (2071–2100, RCP8.5) growing degree days, growing season length, annual precipitation, and aridity index were analyzed using the E‐OBS observational dataset and EURO‐CORDEX regional climate simulations. The study concludes that while marginal land will decrease by ~18%, GR and RCG will profit from the changing European climate, increasing by ~24% and ~13%, respectively. Looking at regions of overlap between marginal land and the selected crops, a decrease of ~87% and an increase of ~462% is projected for RCG and GR, respectively. This is due to marginal land shifting southward, benefitting the warm‐season grass GR, while RCG prefers cooler climates.
Exportstrategien und deren Anforderungen an Management und Organisation
(2019) Raupp, Manfred G.
Hohenheimer Genossenschaftsforschung 2013
(2014) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2014
(2015) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2015
(2016) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2016
(2017) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2017
(2018) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2018
(2019) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2019
(2020) Forschungsstelle Genossenschaftswesen; Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2020
(2021) Doluschitz, Reiner
Hohenheimer Genossenschaftsforschung 2021
(2022) Hess, Sebastian
Hohenheimer Genossenschaftsforschung 2022
(2023) Hess, Sebastian
Land use land/cover change reduces woody plant diversity and carbon stocks in a lowland coastal forest ecosystem, Tanzania
(2022) Ntukey, Lucas Theodori; Munishi, Linus Kasian; Treydte, Anna Christina
The East-African lowland coastal forest (LCF) is one of Africa’s centres of species endemism, representing an important biodiversity hotspot. However, deforestation and forest degradation due to the high demand for fuelwood has reduced forest cover and diversity, with unknown consequences for associated terrestrial carbon stocks in this LCF system. Our study assessed spatio-temporal land use and land cover changes (LULC) in 1998, 2008, 2018 in the LCF ecosystem, Tanzania. In addition, we conducted a forest inventory survey and calculated associated carbon storage for this LCF ecosystem. Using methods of land use change evaluation plug-in in QGIS based on historical land use data, we modelled carbon stock trends post-2018 in associated LULC for the future 30 years. We found that agriculture and grassland combined increased substantially by 21.5% between the year 1998 and 2018 while forest cover declined by 29%. Furthermore, forest above-ground live biomass carbon (AGC) was 2.4 times higher in forest than in the bushland, 5.8 times in the agriculture with scattered settlement and 14.8 times higher than in the grassland. The estimated average soil organic carbon (SOC) was 76.03 ± 6.26 t/ha across the entire study area. Our study helps to identify land use impacts on ecosystem services, supporting decision-makers in future land-use planning.
Method of 3D voxel prescription map construction in digital orchard management based on LiDAR-RTK boarded on a UGV
(2023) Han, Leng; Wang, Shubo; Wang, Zhichong; Jin, Liujian; He, Xiongkui
Precision application of pesticides based on tree canopy characteristics such as tree height is more environmentally friendly and healthier for humans. Offline prescription maps can be used to achieve precise pesticide application at low cost. To obtain a complete point cloud with detailed tree canopy information in orchards, a LiDAR-RTK fusion information acquisition system was developed on an all-terrain vehicle (ATV) with an autonomous driving system. The point cloud was transformed into a geographic coordinate system for registration, and the Random sample consensus (RANSAC) was used to segment it into ground and canopy. A 3D voxel prescription map with a unit size of 0.25 m was constructed from the tree canopy point cloud. The height of 20 trees was geometrically measured to evaluate the accuracy of the voxel prescription map. The results showed that the RMSE between tree height calculated from the LiDAR obtained point cloud and the actual measured tree height was 0.42 m, the relative RMSE (rRMSE) was 10.86%, and the mean of absolute percentage error (MAPE) was 8.16%. The developed LiDAR-RTK fusion acquisition system can generate 3D prescription maps that meet the requirements of precision pesticide application. The information acquisition system of developed LiDAR-RTK fusion could construct 3D prescription maps autonomously that match the application requirements in digital orchard management.
Nachhaltigkeitswettbewerbe in Deutschland 2020 : Übersicht und Methodik der Bestandsaufnahme
(2020) Gebhardt, Beate
This working paper present a systematic collection of German sustainability competitions in 2020 to all interested readers. The collection of 141 sustainability competitions serves as a basis for further projects and studies by the Business Excellence and Sustainability Transformation Working Group (AK BEST), University of Hohenheim. The present collection updates a previous list from 2017.

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