Dissertations / Theses on the topic 'Resource intensification'

This analysis of faunal remains from eleven archaeological sites in the northern San Juan region, extensively occupied by the Ancestral Pueblo people until they leave the region by AD 1300, explores the effects of resource intensification of small wild and domestic resources leading up to this regional depopulation. By examining multiple lines of evidence, in addition to faunal abundance, causal factors are identified to address changes in abundances through time. In particular, age- and sex-based mortality are examined for lagomorphs (jackrabbits and cottontails) and domesticated turkey, respectively, to test hypotheses generated using the prey and patch choice models. Analyses of these resources follow a systematic paleontology which provides explicit identifications made of five sites from a large study area, Goodman Point Pueblo Unit. These data are integrated with those from large village sites from the encompassing central Mesa Verde region. The results of both analyses help clarify why the Ancestral Pueblo people left southwestern Colorado. During the final twenty-year occupation period, the results of this study support a shift from reliance on turkey husbandry to intense exploitation of locally available garden resources (i.e. cottontails).

Thesis (Ph.D.)--Indiana University, Dept. of Anthropology, 2005.
Source: Dissertation Abstracts International, Volume: 67-01, Section: A, page: 0232. Adviser: Patrick J. Munson. "Title from dissertation home page (viewed Dec. 12, 2006)."

Abstract The intellectual assets underpinning the modern knowledge economy are not normally associated with activities in the primary sector. This raises the question whether resourcebased developing countries are eternally relegated to the Also-Runs in global competition or at least whether they need to disassociate themselves from their economic mainstay in order for catch-up to materialise. The answer to this question is of paramount importance to many developing countries, especially in Latin America and Africa. This analysis contributes to the discussion in two novel ways. The first is the focus on technological trajectories that start in or around resource-based activities and subsequently become more knowledge intensive. Hence the study shows the direct contribution resource-based activities make towards the development of a knowledge economy. The second is the attempt systematically to compare technological trajectories in Africa’s most sophisticated economy with those in three Latin American countries at different stages of development. By contrast, this study concentrates on countries from continents that are customarily lumped together in the failure category. It analyses examples of technological learning and focuses on what works (not), and why, and whether insights from a collection of case studies can inform a broader policy discussion about how best to reconcile the demands of the knowledge economy with intensive resource endowments.

This dissertation studies agricultural input intensification, defined as the increased use of modern inputs such as hybrid seeds, mineral fertilizer, herbicide, and pesticide in African agriculture. It also analyses the potential of this intensification to accelerate productivity growth and tests the effectiveness of two policies, input subsidies and land reforms, in promoting it and consequently in increasing crop yield. In the first essay, we argue that to create the conditions for the emergence of a green revolution in Africa, modern agricultural technologies have to be adopted as a package, not in a piecemeal fashion. This argument is consistent with a conceptual framework that we develop to illustrate the importance of harnessing strategic complementarities among agricultural technologies by adopting them simultaneously rather than sequentially. Based on this framework, we propose a methodology to estimate an index to measure agricultural input intensification in its many dimensions. The index provides a simple and intuitive measure to quantify joint adoption of several inputs and compare it across plots, crops, farmers, and regions. Applying this methodology to maize producers in Burkina Faso and Tanzania, we show that our estimated index is a valid measure of joint input adoption and effectively captures the relative importance of each input as well as the number of different inputs adopted. Using the estimated index, we find that simultaneous adoption of modern inputs in Burkina Faso and Tanzania is limited but not rare. Most importantly, we find that the impact of the adoption of individual modern input on yield is increasing with the level of intensification for others. In the subsequent two essays, we assess the effectiveness of government’s direct intervention through input subsidies and indirect intervention through land reforms in promoting agricultural input intensification and increasing productivity. Our empirical analyses focus on Burkina Faso, a country that has recently implemented a fertilizer subsidy program and is undertaking profound land reforms to improve land tenure security and land transferability among households. The second essay tests the hypothesis that subsidizing only one input might promote or discourage the use of other inputs. We find that fertilizer subsidy for maize farmers in Burkina Faso crowds in the use of hybrid seeds and crop protection chemicals, but discourages the use of manure. The last essay assesses whether the development of rural land rental markets can facilitate land transferability among farmers and increase input intensification and productivity. The findings suggest that land rental transfers land from less talented or committed farmers to the more able but have minimal impact on input intensification. However, our results show that land renters are more productive and better farm managers. These results suggest that the short-term gains from policies that foster the development of land rental markets in Burkina Faso, and more generally Africa, will likely be in term of efficiency rather than widespread adoption of modern agricultural technologies.

In this study, I use bioarchaeological data derived from human burials to evaluate subsistence change in mid-to-late Holocene central California (circa 4950-200 B.P.). Previous investigations in the region have proposed two competing models to account for changes in subsistence patterns. The seasonal stress hypothesis argues that the increased reliance on acorns and small seeds during the late Holocene led to improved health status, since these resources could be stored and used as a “buffer” against seasonal food shortages. In contrast, resource intensification models predict temporal declines in health during the late Holocene, as measured by a decline in dietary quality and health status, increased population crowding, and greater levels of sedentism. I test the hypothesis that health status, as measured by childhood stress and disease indicators, declined during the late Holocene in central California. I analyzed 511 human skeletons from ten archaeological sites in the Sacramento Valley and San Francisco Bay area to investigate temporal and spatial variability in diet and health. I analyzed a subset (n = 111) of this sample to evaluate prehistoric dietary patterns using carbon and nitrogen stable isotope ratios. Indicators of health status show significant temporal and regional variation. In the Valley, tibial periosteal reactions, porotic hyperostosis, and enamel hypoplasias significantly increased through time, implying a decline in health status. In the Bay, health indicators show little temporal variability. However, inter-regional comparisons indicate a higher prevalence of stress and disease indicators among Bay Area skeletons than in the Valley skeletal series. The stable isotope data from human bone collagen and apatite also indicate significant interregional differences in prehistoric diets between the Bay and the Valley. In the Bay, diets shifted from high trophic level marine foods to a more terrestrially focused diet over time. In the Valley, there are no significant dietary trends observed in the data. Dental caries and antemortem tooth loss are significantly more prevalent in the Valley than in the Bay, and closely match the isotopic findings. The paleopathological findings provide support for late Holocene resource intensification models posited for the Valley, but not for the Bay Area.

There have been a lot of questions on impact of greenhouse gas on changes in climate conditions regarding expected future dangers if mitigation measures are not put in place. Carbon dioxide emission from power sector is a major contributor of greenhouse gases. As a result, the sector is key target for deploying carbon abatement technologies such as carbon capture. Post-combustion capture (PCC) based on chemical absorption technology is one of the major capture approaches and the most matured of them. However, it is beset by some challenges such as high capital and operating costs due to required large sizes of packed columns and high solvent re-circulating rate. Through process intensification (PI) technology, the columns could be downsized by an order of magnitude without compromising their processing capacity. However, there have been limited studies on the techno-economics of PI-based technologies. In this study, steady state models for standalone intensified absorber and stripper based on rotating packed bed (RPB) technology were developed and validated with experimental data from Newcastle University UK and Tsing Hua University Taiwan respectively. The models were developed in Aspen Plus® and dynamically linked with visual Fortran subroutines. Therefore, this is same as newly developed RPB models (i.e. absorber and stripper). To obtain more insights into the design and operation of standalone intensified absorber, standalone intensified stripper and close loop intensified PCC process, process analysis was carried out. Process analysis in standalone intensified absorber indicates that: (a) CO₂ capture level increases with increase in rotating speed. (b) Higher lean MEA inlet temperature leads to higher CO₂ capture level. (c) Increase in lean MEA concentration results in increase in CO₂ capture level. (d) Temperature bulge is not present in intensified absorber. (e) With fixed RPB equipment size and fixed Lean MEA flow rate, CO₂ capture level decreases with increase in flue gas flow rate. (f) At higher flue gas temperature (from 30°C to 80°C), the CO₂ capture level of the intensified absorber can be maintained. For standalone intensified stripper, the impact of rotor speed on the regeneration efficiency and energy were studied, the impact of reboiler temperature on the rate of CO₂ stripping was established and the impact of rich-MEA flow rate on regeneration energy and efficiency was determined. From comparative assessment of conventional packed bed and RPB, it was found that a volume reduction factor of 12 and 10 times is possible for the absorber and stripper respectively. The two validated models, together with model for heat exchanger were then linked together to form a closed loop intensified PCC process. Steady state model of the closed loop intensified PCC process was then used to perform process analysis on (i) the impact of liquid to gas (L/G) ratio on regeneration energy and CO₂ capture level, (ii) the impact of lean-MEA loading on regeneration energy and capture level (iii) capital and operating cost estimation for intensified PCC process were done, which shows a reduction in an investment cost compared to conventional PCC process. The findings in this study showed that capital and operating costs can be reduced owing to its smaller size compared to conventional PCC process. Also cooling cost for flue gas and inter-cooling in the absorber can be saved since the RPB absorber can be operated at slightly elevated temperature of up to 80°C without compromising the absorber performance and also since higher lean-MEA temperature and/or higher flue gas temperature shows little or no effect on the performance of the RPB. The newly proposed intensified PCC process PFD in the recommendation section of this thesis if successfully implemented can reduce operating and capital costs of PCC process. Finally, these insights can be useful for the design and operation of intensified PCC process.

In order to satisfy the global requirement for transport fuel sustainably, renewable liquid biofuels must be developed. Currently, two biofuels dominate the market; bioethanol for spark ignition and biodiesel for compression ignition engines. However, both fuels exhibit technical issues such as low energy density, poor low temperature performance and poor stability. In addition, bioethanol and biodiesel sourced from first generation feedstocks use arable land in competition with food production, and can only meet a fraction of the current demand. To address these issues it is vital that biofuels be developed from truly sustainable sources, such as lignocellulosic waste resources, and possess improved physical properties. To improve and control the physical properties of a fuel for specific application, one must be able to tailor the products formed in its production process. All studies within this thesis, therefore, have the aim of assessing the fuels produced for their variability in physical property, or the aim of directing the process considered to specific fuel molecules. In Chapter 2, spent coffee grounds from a range of geographical locations, bean types and brewing processes were assessed as a potential feedstock for biodiesel production. While the lipid yield was comparable to that of conventional biodiesel sources, the fatty acid profile remained constant irrespective of the coffee source. Despite this lack of variation, the fuel properties varied widely, presumably due to a range of alternative biomolecules present in the lipid. Though coffee biodiesel was produced from a waste product, the fuel properties were found to be akin to palm oil biodiesel, with a high viscosity and pour point. The blend level would therefore be restricted. In Chapter 3 the coffee lipid, as well as a range of microbial oils potentially derived from renewable sources were transformed into a novel aviation and road transport fuel through cross-metathesis with ethene. Hoveyda-Grubbs 2nd generation catalyst was found to be the most suitable, achieving 41% terminal bond selectivity under optimum conditions. Metathesis yielded three fractions: an alkene hydrocarbon fraction suitable for aviation, a shorter chain triglyceride fraction that upon transesterification produced a short chain biodiesel fuel, and a multifunctional volatile alkene fraction that could potentially have application in the polymer industry. Though there was variation for the road transport fuel fraction due to the presence of long chain saturates, the compounds fell within the US standard for biodiesel. The aviation fraction lowered the viscosity, increased the energy density, and remained soluble with Jet A-1 down to the required freezing point. Oleaginous organisms generally only produce a maximum of 40% lipid, leaving a large portion of fermentable biomass. In Chapter 4, a variety of ethyl and butyl esters of organic acids – potentially obtainable from fermentation – were assessed for their suitability as fuels in comparison to bioethanol. One product, butyl butyrate, was deemed suitable as a Jet A-1 replacement while four products, diethyl succinate, dibutyl succinate, dibutyl fumarate and dibutyl malonate, were considered as potential blending agents for diesel. Diethyl succinate, being the most economically viable of the four, was chosen for an on-engine test using a 20 vol% blend of DES (DES 20) on a chassis dynamometer under pseudo-steady state conditions. DES20 was found to cause an increase in fuel demand and NOx emissions, and a decrease in exhaust temperature, wheel force, and CO emissions. While fermentation is generally directed to one product, producing unimolecular fuels, they do not convert the entirety of the biomass available. An alternative chemical transformation is pyrolysis. In Chapter 5, zeolite-catalysed fast pyrolysis of a model compound representative of the ketonic portion of biomass pyrolysis vapour – mesityl oxide – was carried out. The aim of this study was to understand the mechanistic changes that occur, which could lead to improved bio-oil yields and more directed fuel properties of the pyrolysis oil. While HZSM-5 and Cu ZSM-5 showed no activity for hydrogenation and little activity for oligomerisation, Pd ZSM-5 led to near-complete selective hydrogenation of mesityl oxide to methyl isobutyl ketone, though this reduced at higher temperatures. At lower temperature (150-250 °C), a small amount of useful oligomerisation was observed, which could potentially lead to a selective pyrolysis oligomerisation reaction pathway.

Comprendre comment la biodiversité des prairies répond aux changements d’utilisation des terres constitue un enjeu majeur pour la conservation de la biodiversité et le maintien des services écosystémiques dans les paysages agricoles. Dans ce travail de thèse, nous avons cherché (i) à analyser la réponse simultanée d’un ensemble de taxons appartenant à différents niveaux trophiques (plantes, herbivores, pollinisateurs, prédateurs) aux changements d’utilisation des terres agissant à différentes échelles spatiales et temporelles ; (ii) à approcher les mécanismes impliqués dans cette réponse et notamment le rôle des interactions trophiques. Notre approche est basée sur l’utilisation de multiples traits fonctionnels liés à l’acquisition des ressources, la taille et la mobilité des organismes. Nous avons testé la réponse de ces traits à l’histoire des paysages, leur configuration et leur composition. Nous montrons qu’il existe une réponse générale de la diversité fonctionnelle multitrophique aux changements d’utilisation des terres. Nous mettons en évidence l’importance des effets historiques du changement d’utilisation des terres à l’échelle des paysages agricoles menaçant le maintien de communautés fonctionnellement diversifiées dans ces paysages. En considérant un set de traits multiples, notre travail a permis d’approcher certains mécanismes par lesquels les changements d’utilisation des terres présents et passés impactent différentes facettes de la biodiversité. Enfin, l’utilisation des traits fonctionnels a permis d’appréhender l’importance des interactions trophiques et leur implication dans la structuration des communautés animales dans les milieux agricoles
Understanding how grassland biodiversity responds to land use intensification is crucial for both biodiversity conservation and the management of key ecosystem services in agricultural landscapes. My PhD aims at (i) identifying and generalising the effects of land use intensification operating at different spatial and temporal scales across multiple taxonomic groups and trophic levels (plants, herbivores, pollinators, predators and top-predators) ; (ii) investigating the underlying mechanisms of biodiversity response, and particularly the role of trophic interactions. We used multiple functional traits related to resource acquisition, the size of the organisms and their mobility. We tested how multitrophic functional trait diversity responded to landscape history, composition and heterogeneity. Considering multiple taxonomic groups simultaneously, our study brings out a clear response of overall biodiversity to land use intensification. We found that legacy effects of land use intensification operating at the landscape scale are major drivers of present-day multitrophic functional trait diversity in agricultural landscapes. By considering a core set of organismal traits reflecting similar functions across trophic levels, our approach reveals multiple dimensions by which land use intensification filters out biodiversity over time and allows us to generalise its effect across multiple trophic levels and trait-spectrum. Finally, trait-based approach allowed us to assess the importance of trophic interactions and their contribution in shaping animal communities in agricultural landscapes

Le lac Tchad étonne par sa singularité. Alors que le développement des autres grandes zones humides sahéliennes a reposé sur les périmètres irrigués, le sien a reposé sur la valorisation du mouvement des eaux par l'agriculture, l'élevage et la pêche, et par les mobilités. Quasi espace vierge dans les années 1940, le Lac est devenu une région densément peuplée et cosmopolite exportant des vivriers diversifiés sur les marchés urbains de la sous-région. À travers l'analyse des dynamiques agraires et territoriales de la fenêtre lacustre camerounaise, ce travail interroge les opportunités qu'offrent, dans un environnement incertain, le multiusage des ressources et les mobilités à l'intensification des processus productifs et à la densification démographique.Le renforcement des complémentarités et synergies entre activités dégage les voies d'une intensification écologique du mode d'exploitation et d'un développement territorial, créateurs de richesse et d'emplois. En favorisant l'émergence de rapports sociaux et d'institutions innovantes assurant l'accès aux ressources productives et aux marchés à une grande diversité de populations, le statut de marge territoriale de la fenêtre lacustre a été déterminant dans la dynamique d'intensification. L'incertitude hydro-écologique, économique et démographique a été intégrée au fonctionnement « normal » du système agraire et à celui de territoires qui se singularisent par leur mobilité. Aujourd'hui, c'est l'incertitude politique qui menace l'avenir du lac Tchad. Elle résulte des conflits de pouvoirs locaux constitutifs du rapport de l'État aux populations, et de l'action publique à travers les politiques agricoles et environnementales
The Lake Chad is unique in the Sahelian band. Whereas large scale irrigated schemes has characterized the other wetlands, here the development of agriculture, cattle breeding and fishing has been based on the use of the water floods and on mobilities. Almost virgin until the 1940s, the Lake has become a highly populated and cosmopolitan area, exporting diversified foodstuffs to the urban markets of the sub-region. Through the analysis of agrarian and territorial dynamics of the Cameroonian lake shores, this research questions to which extent multi-use of the natural resources and mobilities may allow further agricultural intensification and population increase in such an uncertain environment.Closer complementarity and synergy between activities pave the way for ecological intensification and territorial development inducing wealth and job generation. Due to its marginal nature, the Cameroonian part of the Lake has been the place of continuous social innovations, ensuring to a great diversity of people the access to productive assets and markets. In this sense, it has been actually decisive for the dynamic of intensification. Hydro-ecological, economic and demographic uncertainty has been integrated into the “normal” functioning of the agrarian system and territory. Nowadays, the political uncertainty threatens the future of the Lake Chad. It results both from agricultural and environmental policies and from conflicts between local authorities, that are constitutives of the relation between the State and the populations

It is now widely accepted that over one-third of the global food supply depends upon pollinators. Risking severe ecological and economic implications, the status of the 4000 species of bees native to North America has been poorly understood due to a lack of long-term survey data. In this study, I conducted bee surveys on Massachusetts cranberry (Vaccinium macrocarpon Ait.) bogs from 2007-2009 and compared diversity and abundance data to those from historical surveys performed in 1990-1992 on the same bogs. I found that overall bee diversity declined severely in the 19-year survey period, while total bee abundance remained consistent. My data provide supporting evidence for the loss of North American bumble bees (Bombus spp.), but also provide the first evidence for declines in the U.S. in overall wild bee diversity. Maximizing the potential for agricultural landscapes to serve as quality pollinator habitat and identifying appropriate integrated pest management strategies should involve a comprehensive understanding of each species’ life history traits and conservation status. The loss of biodiversity associated with the intensification of agriculture has been well documented for several wildlife species but remains poorly understood for bees, which provide pollination to many agricultural crops. Most pollinator-dependent crops rely heavily on managed honey bees (Apis mellifera L.) for pollination. Four thousand other species of bees native to North America may provide pollination insurance in the event of honey bee losses, but without a clear understanding of how agricultural intensification affects wild bees, habitat conservation measures aimed at protecting them may be futile. In the second part of this study, I evaluated six metrics of agricultural intensification with respect to native bee diversity and abundance in Massachusetts cranberry bogs, including honey bee competition, bog management type (i.e. organic versus conventional), distance from epicenter of cranberry-growing region, toxicity of insecticide program, susceptibility of reproductive bees to insecticide, and surrounding land use. I found a clear association between reduced native bee diversity and abundance and the effects of increased agricultural intensification of the landscape. Recognition that native bee communities in North America are diminishing as a consequence of agricultural intensification may help to unify a movement toward improved conservation management.