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1

Nili, Farhad. "Economic growth, development and exhaustible natural resources". Thesis, University of York, 2002. http://etheses.whiterose.ac.uk/14160/.

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Bergholt, Drago. "Natural Disasters, Economic Growth and Armed Civil Conflict". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for samfunnsøkonomi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10170.

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Catastrophes such as floods, droughts and earthquakes have caused significant human and infrastructural losses throughout history. Nevertheless, researchers struggle to quantify macroeconomic impacts, and the existing literature is ambiguous in its findings. In this study I use econometric methods on panel data from Centre for Research on the Epidemiology of Disasters (CRED), and find that hydrometeorological, climatological and geophysical events all affect economic growth negatively in the short run. Second, while events typically linked to climate change tend to cause negative growth shocks the same year they occur, geophysical disasters do not alter overall economic performance before the next year. With respect to future global warming, these dynamic differences give important insights for the understanding of how economies might be affected by climate change. However, by means of two stage least square methods, I do not find that negative economic shocks caused by weather related disasters increase the likelihood of armed civil conflicts. This latter result is in contrast to conclusions in much of the seminal conflict literature, but similar to findings in other recent cross-country studies that use the instrument variable approach.
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3

Mistry, Manisha. "The surface structure and growth of natural zeolites". Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444850/.

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A systematic study has been carried out in order to investigate two aspects of zeolite chemistry: to determine the external surface structure and to establish the mechanism of crystal growth. The natural zeolite edingtonite (EDI) was chosen as a model material and the surface structures were studied by finding the most stable termination for each face. For each of the four morphologically important faces the surface structure was found to minimise the number of broken bonds created upon cleaving the surface. In the absence of experimental data, the crystal morphologies were used as a proxy indicator of relative growth rate of different faces. Qualitative inspection indicates that only the equilibrium morphology is able to reproduce the habit of the natural crystal. However, quantitative analysis with the crystal habit observed in SEM images reveals a discrepancy in aspect ratios. By predicting the crystal morphology by using a newly proposed, less demanding method of calculating the number of broken bonds upon cleaving the surface per surface area (Nbb/SA), one is able to accurately reproduce the crystal morphology with the correct aspect ratio. The utility of the NBb/SA method has been tested for a sample of zeolites, results show the Nbb/SA technique has correctly predicted the growth rate and crystal habit of merlinoite, analcime, natrolite, and zeolite A. The test on thomsonite was able to reproduce the correct order of stability for each face, however the aspect ratios were not precisely predicted. By the use of atomistic and ab-initio methods, this research has also investigated the growth mechanism of EDI. The total and condensation energies of a range of possible solution fragments have been calculated and the most stable cluster along with the mechanism of formation has been suggested. The energetics of clusters along with the surface structural analysis has shown strong evidence that characteristic building units control the growth and aggregation of EDI, which dictates the extended crystal structure and the rate at which these building units condense onto the surface determines the crystal shape.
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4

Zuo, Na. "NATURAL RESOURCE, REGIONAL GROWTH, AND HUMAN CAPITAL ACCUMULATION". UKnowledge, 2017. http://uknowledge.uky.edu/agecon_etds/58.

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The dissertation research will comprise three essays on the topic of the resource curse hypothesis and its mechanisms. The phenomenon of low economic growth in resource-rich regions is recognized as the “resource curse”. These essays will contribute to an understanding of the regional resource-growth relation within a nation. Essay one tests the resource curse hypothesis at the U.S. state level. With a system of equations model, I decompose the overall resource effect to account for the two leading explanations — crowding-out and institution effects, thus investigate whether the institutions mediate the crowding-out effects. I did not find evidence of an overall negative effect on growth by resource wealth. Both the crowding-out and institution appear present, but they offset: the resource boom crowds out industrial investments, but good institutions mitigate the overall effect. Resources do reduce growth in states with low-quality institutions, including Louisiana, Oklahoma, and Texas. Essay two compares the effects of resource revenues on the economic growth and growth-related factors across Chinese provinces and American states, using panel data from 1990 to 2015. With the Instrumental Variable (IV) strategy, I show that regions with higher resource revenues grow faster than other regions in both China and the U.S. The positive resource effect is larger and more statistically significant in the U.S. Further testing impacts of three resource-related policies in China, e.g. the market price reform, the fiscal reform, and the Western Development Strategy, I show that the market price reform together with the privatization process on coal resources contribute the positive resource effect in China. Though strong and positive resource – growth relations appear in both countries, evidence also suggests consistent negative resource effects on certain growth-related factors in both countries, such as educational attainments and R&D activities. Essay three explores the schooling response to the oil and gas boom, taking advantage of timing and spatial variation in oil and gas well drilling activities. Development of cost-reducing technologies at the time of higher crude oil and natural gas prices in the early 2000s has accelerated shale oil and gas extraction in the United States. I show that intensive drilling activities have decreased grade 11 and 12 enrollment over the 14 year study window − approximately 36 fewer students per county on average and overall, 41,760 fewer students across the 15 states enrolled considered in the analysis. On average, with one additional oil or gas well drilled per thousand initial laborers, grade 11 and 12 enrollment would decrease 0.24 percent at the county level, all else equal. I investigate heterogeneous effects and show that the implied effect of the boom is larger in states with a younger compulsory schooling age requirement (16 years of age instead of 17 or 18), lower state-level effective tax rate on oil and gas productions, traditional mining, non-metro, and persistent poverty counties.
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5

Hermnann, Frederiksen Elisabeth. "Inquiries into economic growth, natural resources, and labour allocation /". Copenhagen, 2007. http://www.gbv.de/dms/zbw/545715474.pdf.

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6

Patey, Susannah Juliet. "Fibroblast growth factor receptor function : analysis through natural mutations". Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400436.

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7

Motie, Richard Edward. "Crystal growth and inhibition mechanisms of natural gas hydrates". Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441228.

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Nguyen, Thi Tuyet Mai. "Essay on natural resources, economic growth, development and equity". Thesis, Paris 1, 2020. http://www.theses.fr/2020PA01E019.

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Le développement durable est un sujet attractif pour les économistes. Dans la littérature sur la croissance économique et le développement durable, deux approches fondamentales sont utilisées dans la plupart des discussions. Le premier est de reconnaître l'importance des ressources naturelles ainsi que les stratégies d'utilisation de ces ressources pour le développement économique dans le contexte de leur épuisement. Le deuxième est la question de l'équité intergénérationnelle dans laquelle les besoins des générations présentes peuvent être assurés sans compromettre la capacité de répondre aux besoins des générations futures. Ma thèse vise à étudier des modèles théoriques sur les ressources naturelles, la croissance économique, le développement et l'équité. Le chapitre 1 examine une économie à deux secteurs avec des externalités. Nous étudions un modèle théorique qui étudie la relation entre la dynamique optimale de la croissance économique utilisant des ressources renouvelables et la qualité de l'environnement. Dans ce modèle, le secteur industriel utilise des intrants intermédiaires pour produire un bien de consommation finale, et un autre secteur, appelé secteur d’exploitation, s’engage dans l’exploitation d’une ressource renouvelable. Cette ressource peut être vendue directement à un prix de marché déterminé de manière exogène, générant une source de revenus supplémentaire. Nous prenons également en compte les externalités négatives du secteur industriel polluant sur la capacité de régénération du secteur des ressources renouvelables. Sans la convexité habituelle ou la super-modularité, nous prouvons que l'économie évolue pour augmenter le gain net de stock un jour dans le futur. Cette propriété garantit qu'à long terme. L’économie se rapproche beaucoup d'un état stable. Nous établissons également les conditions assurant la convergence de l'économie à long terme. Pour le développement durable, l'un des problèmes les plus difficiles liés aux critères de la fonction de protection sociale est la réconciliation entre l'égalité et l'efficacité. L'Axiome d’anonymat déclare que l’ordre social est invariant aux informations concernant les ordres individuels. L’axiome de Pareto impose que si au moins une génération augmente son utilité, le bien-être social doit s’améliorer. Cependant aucun SWF ne satisfait à la fois les axiomes d'anonymat et de pareto. Afin de surmonter cette difficulté, certains auteurs proposent plusieurs approches pour atténuer ces axiomes. Par conséquent, de nombreux critères ont été introduits, tels que : dominance, domination faible, pareto faible, monotonie, etc. Dans le deuxième chapitre de ma thèse, nous avons revisité certaines propriétés d’un SWF dans la littérature, en tenant compte de la continuité de ce SWF sous différentes topologies. De plus, nous proposons les notions de non-dictature faible et de forte dictature du présent et du futur suivant l’esprit de Chichilniski, et fournissons une description détaillée des paramètres caractérisant les deux non-dictature. Dans le chapitre 3, nous étudions un problème d’optimisation inter-temporelle en utilisant un critère qui est une combinaison entre les critères de Ramsey et Rawls. Une description détaillée du comportement d’économie dans le temps est fournie.[...] Le dernier chapitre développe un modèle théorique pour accéder aux déterminants de l’efficacité de la Zone Économique Spéciale et aux conditions de la mise en œuvre. Les résultats de cette étude montrent qu’il existe un seuil tel que pour toutes les économies initiales d’un pays au-dessus de ce niveau, il sera optimal d’investir dans de nouvelles technologies. De plus, plusieurs facteurs dont le prix du capital technologique, le salaire de la main d’œuvre hautement qualifiée, le revenu initial de l’économie et la productivité totale des facteurs dans le secteur des ZES, déterminent de manière endogène ce seuil
Sustainable development is an attractive topic for economists. In the literature on economic growth and sustainable development, there are two core approaches used in most discussions. The first one is recognizing the importance of natural resources as well as strategies for using these resources for economic development in the context of their depletion. The second one is the issue of intergenerational equity in which the needs of the present generations can be assured without compromising the ability to meet the needs of the future generation. My thesis aims to study theoretical models on natural resources, economic growth, development and equity. Chapter I considers a two-sector economy with externalities. We study a theoretical model that investigates the relationship between the optimal dynamics of economic growth using renewable resources and environmental quality. In this model, the industrial sector uses intermediate inputs to produce a final consumption good, and another sector, called the exploitation sector, engages in exploiting a renewable resource. This resource can be sold directly at an exogenously determined market price, generating an additional source of income. We also take into account the negative externalities of the polluting industrial sector on the regenerating capacity of the renewable resource sector. Without the usual convexity or the super-modularity, we prove that the economy evolves to increase the net gain of stock some day in the future. This property ensures that in the long run, the economy gets very close to a steady state. We also establish the conditions ensuring the convergence of the economy in the long run. For sustainable development, one of the most difficult problems relying on criteria for Social Welfare Function is the reconciliation between equality and efficiency. The Anonymity Axiom states that the social ordering is invariant to the information regarding individual orderings. The Pareto Axiom imposes that if at least one generation increases its utility then the social welfare must improve. However, there is no SWF which satisfies both the Anonymity and Pareto Axioms. To overcome this difficulty, some authors propose several approaches to mitigate these axioms. Therefore, a lot of criteria have been introduced such as: Dominance, Weak Dominance, Weak Pareto, Monotonicity and so on. In the second chapter of my thesis, we have revisited some properties of a SWF in the literature taking into account the continuity of this SWF under different topologies. […] Furthermore, we propose the notions weak no-dictactorship and strong no-dictatorship of the present and the future following the spirit of Chichilniski and provide a detailed description for parameters characterizing the two No dictatorship. In chapter 3, we study an inter-temporal optimization problem using a criterion which is a combination of Ramsey and Rawls criteria. A detailed description of the saving behavior through time is provided. […] The last chapter develops a theoretical model to access the determinants of the effectiveness of Special Economic Zone and the conditions for its implementation. The results of this study show that there is a threshold such that for all the initial savings of a country above this level, it will be optimal to invest in new technology. Moreover, several factors including the price of technological capital, the wage of high-skilled labor, the initial income of the economy and the total factor productivity in the SEZ sector, endogenously determine this threshold. This chapter also proposes a service sector as an additional source to the accumulated capital, that can help the country pass this threshold
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9

Hashemi, Mohammad. "Lattice Boltzmann Simulation of Natural Convection During Dendritic Growth". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1459444594.

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Reavis, Dena L. "Natural resources, investment, and growth in low income countries /". View online, 2009. http://repository.eiu.edu/theses/docs/32211131590402.pdf.

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11

Frederiksen, Elisabeth Hermann. "Inquiries into economic growth, natural resources, and labor allocation". Kbh. : Department of Economics, University of Copenhagen, 2007. http://www.econ.ku.dk/Research/Publications/red/Red120.pdf.

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12

Gerard, Bryce. "A Natural Resource Curse: Does it Exist Within the United States?" Scholarship @ Claremont, 2011. http://scholarship.claremont.edu/cmc_theses/158.

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In this paper, we examine data on U.S. GDP/Capita and natural resource share of GDP by state. We then run growth regressions and build on a previous model of dynamic equations to account for the spatial equilibrium that exists between U.S. states. Our results show that there exists evidence that overinvestment in oil and mining sectors has negative effects on state TFP growth, thus giving positive evidence for the existence of a natural resource curse between U.S. states.
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13

Leone, Stefano. "Advances in SiC growth using chloride-based CVD". Doctoral thesis, Linköpings universitet, Halvledarmaterial, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-60226.

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Silicon Carbide (SiC) is a wide band-gap semiconductor. Similar to silicon it can be used to make electronic devices which can be employed in several applications. SiC has some unique features, such as wide band-gap, high hardness, chemical inertness, and capability to withstand high temperatures. Its high breakdown electric field, high saturated drift velocity and high thermal conductivity are some of the most important characteristics to understand why SiC has superior electrical properties compared to silicon, and make it very attractive for power devices especially at high voltages and high frequency. The gain in reduced device sizes, reduced cooling requirements, and especially in improved energy efficiency for AC/DC conversion are a very important reasons to keep working in improving the material quality. Yet several issues still limit its full employment in all its potential applications, and many more steps have thus to be done for its complete success. The core of an electric device is the epitaxial layer grown on a substrate by chemical vapor deposition (CVD). Gases containing silicon and carbon atoms, such as silane and ethylene, are often used to grow SiC, but limits in high growth rate are given by silicon cluster formation in the gas phase which is detrimental for the epitaxial layer quality. High growth rates are needed to deposit thick layers ( > 100 μm) which are required for high power devices. Chloride-based CVD, which is usually employed in the silicon epitaxial growth industry, is based on the presence of chlorinated species in the gas mixture which prevent the formation of silicon clusters, therefore resulting in very high growth rates. This chloride-based CVD process was first started to be investigated a few years ago and then only at typical growth conditions, without exploring all its full potential, such as its performance at low or high temperature growth. In addition important parameters affecting the epitaxial layer quality in terms of defect formation and electrical characteristics are the substrate orientation and its off-cut angle. Standard processes are run on substrates having an 8° off-cut angle towards a specific crystallographic direction. On lower off-cut angles, such as 4° or almost 0° (also called on-axis) which would be more economical and could resolve problems related to bipolar degradation, many typical issues should be solved or at least minimized. For 4° off-cut angle the main problem is the step-bunching resulting in high roughness of the epi surface whereas for nominally on-axis the formation of 3C inclusions is the main problem. In this thesis we discuss and present results on the use of the chloride-based CVD process in a hot-wall reactor to further explore most of the above mentioned topics. Onaxis substrates are used to grow homopolytypic epitaxial layers; detailed experiments on the gas phase composition adopting high contents of chlorine made it possible (Paper 1). Optimization of the on-axis surface preparation prior to the growth in combination with a correct choice of chlorinated precursors and growth conditions were required to reach a growth rate of 100 μm/h of 100% 4H polytype (Paper 2). Substrates with a 4° off-cut angle could be grown free from step-bunching, one of the most common morphological issue and usually detrimental for devices. Both the standard and chlorinated-process were successfully used, but at different growth rates (Paper 3). Also for this off-cut substrate a specific surface preparation and selected growth parameters made the growth possible at rates exceeding 100 μm/h (Paper 4). The benefit of the chlorinated chemistry was tested under unusual growth conditions, such as under a concentrated gas mixture (i.e. at very low carrier gas flow) tested on different off-cut substrates (Paper 5). A great advantage of chloride-based chemistry is the feasibility of growing at very low temperatures (1300 to 1400 °C compared to the 1600 °C standard temperature). At such low temperatures 4H-SiC epitaxial layers could be grown on 8° off-axis substrates (Paper 6), while high quality heteroepitaxial 3C-SiC layers were grown on on-axis 6H-SiC substrates (Paper 7). Finally, the very high growth rates achieved by the chloride-based CVD were applied in a vertical hot-wall reactor configuration, demonstrating the ability to grow very thick SiC layers at higher rates and lower temperatures than what is typically used for bulk growth (Paper 8). This work demonstrated that a new bulk growth process could be developed based on this approach.
Kiselkarbid (SiC) är en halvledare med ett stort bandgap och precis som den mycket vanliga halvledaren kisel kan SiC användas till elektroniska komponenter för många olika tillämpningar. SiC har unika materialegenskaper så som dess stora bandgap, dess höga hårdhet och motståndskraft både mot kemiskt aggressiva miljöer och höga temperaturer. Det som framförallt gör SiC så mycket bättre än kisel är främst den höga genombrottsfältstyrkan som gör att SiC klarar höga spänningar vilket är särskilt intressant för kraftkomponenter, för användning vid höga spänningar och höga frekvenser. Med elektroniska komponenter av SiC kan man, jämfört med samma komponenter av kisel, minska komponenternas storlek och kylbehov, men den huvudsakliga vinsten är en högre energieffektivitet vid AC/DC-omvandling. De minskade energiförlusterna är ett mycket starkt argument för att fortsätta att förbättra materialkvalitén på SiC. Det är materialrelaterade problem som idag håller tillbaka SiC-teknologin och ett antal problem måste lösas för att SiC ska få sitt stora genombrott. Kärnan i en elektronisk komponent är det epitaxiella skikt som har växts ovanpå ett substrat. Ordet epitaxi kommer från grekiskans epi, som betyder ovanpå, och taxis, som betyder i ordning, så ett epitaxiellt skikt har alltså odlats på ett substrat och kopierat substratets kristallstruktur. Den vanligaste tekniken för att odla epitaxiella skikt i halvledarindustrin kallas på engelska chemical vapor deposition. Någon bra svensk översättning finns inte men tekniken innebär att man deponerar ett tunt skikt via kemiska reaktioner mellan gaser. Tekniken förkortas generallt för CVD från dess engelska namn. För att odla ett epitaxiellt skikt av SiC använder man gaser med kisel och kol, så som silan (SiH4) och eten (C2H4), som späds ut kraftigt i vätgas. För att öka tillväxthastigheten i processen måste man öka mängden silan och eten i gasblandningen. Ett problem är dock att vid höga koncentrationer av kisel bildas kiseldroppar som regnar ner på substratytan och förstör det epitaxiella skiktet. Detta faktum gör att man inte kan odla epitaxiella skikt av SiC snabbare än ca 5-10 μm i timmen. För många kraftkomponenter krävs epitaxiella skikt med en tjocklek på 100 μm, eller mer och för att kunna odla sådana skikt på rimlig tid används kloridbaserad CVD. Kloridbaserad CVD är idag standard i kiselindustrin och bygger på närvaron av klorföreningar i gasblandningen. Eftersom klor binder starkare till kisel än vad kisel gör, hindrar närvaron av klor bildningen av kiseldroppar och man kan öka koncentrationen av kisel i gasblandningen och därmed öka tillväxthastigheten betydligt. Kloridbaserad CVD för kiselkarbid började på allvar undersökas för snart tio år sedan och då var fokus främst på redan välkända tillväxtförhållanden, men den fulla potentialen hos kloridbaserad CVD, så som dess effekt på låg-  eller högtemperatur tillväxt har ännu inte studerats. Inte heller har grundliga undersökningar gjorts av vad det är i processen som har betydelse för det epitaxiella skiktets elektriska egenskaper eller för bildandet av olika defekter under tillväxten. När man kapar upp en kiselkarbidkristall i tunna skivor för att kunna odla epitaxiella skikt på dem, kapar man ofta kristallen lite snett i förhållande till hur atomplanen ligger i den. Detta gör att man får en kristallyta som ser ut lite som en trappa på atomär nivå. Detta är bra eftersom atomer som ska bygga upp det epitaxiella skiktet gärna binder till ytan vid ett sådant trappsteg eftersom de där kan binda till flera atomer samtidigt. Substrat som har kapats snett på det viset kallas off-axis substrat och för 4H-polytypen av SiC kapar man vanligen substraten 8 eller 4° snett. Substrat som kapats helt parallellt med kristallplanen kallas on-axis substrat, dessa är generellt sett svåra att odla bra epitaxiella skikt på, men man får inga spillbitar när man kapar kristallen och vissa kristalldefekter i substratet tränger inte igenom till episkiktet vilket ger bättre livslängd för de elektroniska komponenterna. För att kunna odla på on-axis substrat gjordes detaljerade undersökningar av olika gasblandningar för processen och en hög klorhalt i gasblandningen möjliggjorde en process med hög tillväxthastighet på on-axis substrat (Artikel 1). Ytterligare optimering av både gaskemin och etsning av substratytan innan tillväxt gjorde att tillväxthastigheter på 100 μm i timmen kunde användas (Artikel 2). För substrat med 4° off-axis-vinkel utvecklades en process för odling av epitaxiella skikt där vanliga kristalldefekter, som är förödande för en elektrisk komponent, eliminerades och tack vare den kloridbaserade kemin kunde skikten odlas med relativt hög hastighet (Artikel 3). Även denna process utvecklades så att tillväxthastigheten överskred 100 μm i timmen (Artikel 4). Den kloridbaserade processen testades även under mera ovanliga tillväxtförhållanden, så som under väldigt lågt vätgasflöde, alltså väldigt hög koncentration av både kisel och kol i gasblandningen (Artikel 5). Den kloridbaserade kemin möjliggjorde även tillväxt vid låga temperaturer, 1300-1400 °C i stället för 1600 °C vilket är av stort intresse för vissa applikationer. Epitaxiella skikt hög kvalité av både hexagonal 4H-SiC (Artikel 6) och kubisk 3CSiC (Artikel 7) odlades vid låga temperaturer på substrat av hexagonal SiC. Slutligen användes även den kloridbaserade kemin för att odla tjocka epitaxiella skikt vid högre temperaturer, 1700-1800 °C, med en mycket hög tillväxthastighet (Artikel 8). Detta är ett första steg mot en kloridbaserad process för att odla SiC bulkkristaller som sedan kan kapas till SiC substrat. Tack vare den kloridbaserade kemin kan betydligt lägre temperaturer än standard bulkprocesser användas som har en process temperatur på ca 2100-2400 °C.
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14

Žukauskaitė, Agnė. "Metastable YAlN and ScAlN thin films : growth and characterization". Licentiate thesis, Linköpings universitet, Tunnfilmsfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76474.

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ScxAl1-xN and YxAl1-xN thin films were deposited in a ultra high vacuum system using reactive magnetron co-sputtering from elemental Al, Sc and Y targets in Ar/N2. Their mechanical, electrical, optical, and piezoelectrical properties were investigated with the help of transmission electron microscopy, xray diffraction, ellipsometry, I-V and C-V measurements, and two different techniques for piezoelectric characterization: piezoresponse force microscopy and double beam interferometry. Compared to AlN, improved electromechanical coupling and increase in piezoelectric response was found in ScxAl1-xN/TiN/Al2O3 structures with Sc content up to x=0.2. Microstructure of the films had a stronger influence on piezoelectric properties than the crystalline quality, which affected the leakage currents. YxAl1-xN thin films show a formation of solid solution up to x=0.22. Lattice constants obtained experimentally are in good agreement with theoretical predictions obtained through first principle (ab initio) calculations using density-functional formalism. The mixing enthalpy for wurtzite, cubic, and layered hexagonal phases of the YxAl1-xN system was also calculated.
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15

Elíasson, Lúðvík. "Economic growth with a renewable resource sector /". Thesis, Connect to this title online; UW restricted, 2001. http://hdl.handle.net/1773/7378.

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McGonigle, T. P. "Vesicular-arbuscular mycorrhizas and plant performance in a semi-natural grassland". Thesis, University of York, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379456.

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ul, Hassan Jawad. "Epitaxial Growth and Characterization of SiC for High Power Devices". Doctoral thesis, Linköpings universitet, Halvledarmaterial, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17440.

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Silicon Carbide (SiC) is a semiconductor with a set of superior properties, including wide bandgap, high thermal conductivity, high critical electric field and high electron mobility. This makes it an excellent material for unipolar and bipolar electronic device applications that can operate under high temperature and high power conditions. Despite major advancements in SiC bulk growth technology, during last decade, the crystalline quality of bulk grown material is still not good enough to be used as the active device structure. Also, doping of the material through high temperature diffusion is not possible while ion implantation leads to severe damage to the crystalline quality of the material. Therefore, to exploit the superior quality of the material, epitaxial growth is a preferred technology for the active layers in SiC-based devices. Horizontal Hot-wall chemical vapor deposition is probably the best way to produce high quality epitaxial layers where complete device structure with different doping type or concentrations can be grown during a single growth run. SiC exists in many different polytypes and to maintain the polytype stability during epitaxial growth, off-cut substrates are required to utilize step-flow growth. The major disadvantage of growth on off-cut substrates is the replication of basal plane dislocations from the substrate into the epilayer. These are known to be the main source of degradation of bipolar devices during forward current injection. The bipolar degradation is caused by expanding stacking faults which increases the resistance and leads to fatal damage to the device. Structural defects replicated from the substrate are also important for the formation of defects in the epitaxial layer. In this thesis we have developed an epitaxial growth process to reduce the basal plane dislocations and the bipolar degradation. We have further studied the properties of the epitaxial layer with a focus on morphological defects and structural defects in the epitaxial layer. The approach to avoid basal plane dislocation penetration from the substrate is to grow on nominally on-axis substrate. The main obstacle with on-axis growth is to avoid the formation of parasitic 3C polytype inclusions. The first results (Paper 1) on epitaxial growth on nominally on-axis Si-face substrates showed that the 3C inclusions nucleated at the beginning of the growth and expand laterally without following any particular crystallographic direction. Also, the extended defects in the substrate like micropipes, clusters of threading screw and edge dislocations do not give rise to 3C inclusion. The substrate surface damage was instead found to be the main source. To improve the starting surface different in-situ etching conditions were studied (Paper 2) and Si-rich conditions were found to effectively remove the substrate surface damages with lowest roughness and more importantly uniform distribution of steps on the surface. Therefore, in-situ etching under Si-rich conditions was performed before epitaxial growth. Using this 100 % 4H polytype was obtained in the epilayer on full 2” wafer (Paper 3) using an improved set of growth parameters with Si-rich conditions at the beginning of the growth. Simple PiN diodes were processed on the on-axis material, and tested for bipolar degradation. More than 70 % of these (Paper 4) showed a stable forward voltage drop during constant high current injection. High voltage power devices require thick epitaxial layers with low doping. In addition, the high current needs large area devices with a reduced number of defects. Growth and properties of thick epilayers have been studied in details (Paper 5) and the process parameters in Horizontal Hotwall chemical vapor deposition reactor are found to be stable during the growth of over 100 µm thick epilayers. An extensive study of epitaxial defect known as the carrot defect has been conducted to investigate the structure of the defect and its probable relation to the extended defects in the substrate (Paper 6). Other epitaxial defects observed and studied were different in-grown stacking faults which frequently occur in as-grown epilayers (Paper 7) and also play an important role in the device performance. Minority carrier lifetime is an important property especially for high power bipolar devices. The influence of structural defects on minority carrier lifetime has been studied (Paper 8) in several epilayers, using a unique high resolution photoluminescence decay mapping. The technique has shown the influence on carrier lifetime from different structural defects, and also revealed the presence of non-visible structural defects such as dislocations and stacking faults, normally not observed with standard techniques.
Kiselkarbid (SiC) är en halvledare med överlägsna materialegenskaper, stort bandgap, hög termisk konduktivitet, hög kritisk fältstyrka och hög elektron mobilitet. Dessa gör den till ett utmärkt material för unipolära och bipolära komponenter som kan användas vid höga temperaturer, höga spänningar och höga strömmar. Trots stora framsteg under de senaste åren inom SiC bulk tillväxt, är material kvalitén hos bulk material fortfarande inte tillräckligt bra för att användas för aktiva skikt i komponenterna. Dessutom är dopning av materialet genom diffusion vid höga temperaturer inte möjligt, medan dopning via jonimplantation ger upphov till stora skador i kristallstrukturen. Därför behövs epitaxiell tillväxt av de aktive skikten i SiC baserade komponenter, för att fullt kunna utnyttja materialets egenskaper. Horisontell CVD (Hot-Wall Chemical Vapor Deposition) är en av de bästa tekniker att producera epitaxiella skikt med hög kvalité, där kompletta komponent strukturer med olika dopnings typ och koncentrationer kan växas i samma körning. SiC existerar i många polytyper och för att bibehålla polytype stabiliteten under tillväxt, används substrat med lutande kristallplan för använda s.k. step-flow tillväxt. En stor nackdel med substrat med lutande kristallplan är dock att dislokationer i basalplanet kommer att propagera från substratet in i det epitaxiella skiktet under tillväxten. Dessa dislokationer är den huvudsakliga orsaken till den degradering av bipolära komponenter som uppstår då höga strömmar går igenom komponenten. Den bipolära degraderingen orsakas av expanderade staplingsfel, som successivt ökar resistansen och slutligen förstörs komponenten. Strukturella defekter som replikeras från substratet är ofta även orsaken till kritiska defekter som skapas i det epitaxiella skiktet under tillväxt. I den här avhandlingen har vi utvecklat en epitaxiell som minskar problemet med basalplans dislokationer och bipolär degradering. Vi har även studerat egenskaper hos de epitaxiella skikten med fokus på morfologiska och strukturella defekter. Tekniken att hindra dislokationerna att replikeras in i de epitaxiella skikten bygger på att använda substrat utan lutning hos kristallplanen, s.k. on-axis substrat. Det hittills stora problemet med att växa på on-axis substrat har varit svårigheterna att bibehålla polytyp stabiliteten och undvika framförallt 3C polytyp inklusioner. Första försöken (Papper 1) försöken att växa epitaxi på on-axis substrat på Si sidan visade att 3C inklusionerna alltid startade i början av tillväxten för att sedan sprida sig lateralt under den fortsatta tillväxten. Vi kunde också visa att strukturella defekter som mikropipor, eller kluster av skruv- eller kant- dislokationer inte orsakade 3C inklusionerna. Den dominerande orsaken till 3C inklusionerna var istället skador eller repor på substratets yta. För att förbättra ytan innan den epitaxiella tillväxten studerade vi olika in-situ etsningar av ytan (Papper 2), och vi fann att etsning under Si dominerande förhållanden effektivast tog bort de flesta skador på substratets yta och gav en yta med minst ojämnheter. Dessutom skapades en homogen fördelning av atomära steg på ytan, och denna förbehandling användes sedan inför den epitaxiella tillväxten. Genom att dessutom optimera tillväxt förhållandena i inledningen av tillväxten kunde vi till 100% bibehålla samma polytyp från substratet in i det epitaxiella skiktet för hela 2” substrat (Papper 3). Enkla bipolära PiN dioder tillverkades och testades med avseende på bipolär degradering och mer än 70% av dioderna (Papper 4) visade ett stabilt framspänningsfall vid höga strömtätheter. Kraftkomponenter för höga spänningar kräver tjocka epitaxiella skikt med låg dopning. Dessutom, för höga strömmar krävs komponenter med stor aktiv area där kravet på lägre defekt täthet blir allt viktigare. Vi har i detalj studerat tillväxt och egenskaper av tjocka skikt (Papper 5), och funnit att de flesta material egenskaperna är stabila vid tillväxt av över 100 mm tjocka skikt i vår horisontella CVD reaktor. Vi har även i detalj studerat uppkomst och egenskaper av en av de mest kritiska epitaxiella defekterna, dem s.k. moroten (Papper 6). Speciellt har vi studerat dess uppkomst i relation till strukturella defekter i substratet. Vi har även studerat ända epitaxiella defekter i form av olika typer av staplingsfel (Papper 7), som även dessa har stor inverkan på komponenter. Livstiden för minoritetsladdningsbärarna är en viktig egenskap hos speciellt bipolära komponenter. I (Papper 8) har vi studerat hur denna påverkas av strukturella defekter i de epitaxiella skikten. Vi har använt en unik mätmetod för att optiskt kunna mäta över hela skivor, med hög upplösning. Mätningarna har lyckats påvisa hur olika strukturella defekter påverkar livstiden, och även kunnat visa på förekomsten av defekter som inte har upptäckts med andra mätmetoder.
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18

Fager, Hanna. "Growth and Characterization of Amorphous TiAlSiN and HfAlSiN Thin Films". Licentiate thesis, Linköpings universitet, Tunnfilmsfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-80211.

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This Thesis explores amorphous transition metal nitrides for cutting tool applications. The aim is to extend the knowledge on amorphous nitride thin lms, to describe the growth process, and to explore ways of characterizing these novel complex materials. Thin lms of Ti-Al-Si-N and Hf-Al-Si-N were fabricated using industrial cathodic arc evaporation and magnetically-unbalanced reactive magnetron sputtering, respectively. The microstructure of the lms was studied using x-ray diraction (XRD) and transmission electron microscopy (TEM), while compositional analysis of the lms was performed by spectroscopic techniques (EDS, SIMS, and RBS). The mechanical properties were investigated by nanoindentation. The Ti-Al-Si-N lms were grown on cemented carbide substrates using Ti-Al-Si compound cathodes in an N2 atmosphere. High Al and Si concentrations in the lms (i.e., 12 at% Si and 18 at% Al) promote renucleation and result in x-ray amorphous lms. High resolution TEM (HRTEM) reveals isolated grains, ~2 nm in size, embedded in an amorphous matrix. Annealing experiments show that the lms are thermally stable up to 900 oC. They exhibit age hardening, with an increase in hardness from 21.9 GPa for as-deposited lms to 31.6 GPa at 1000 oC. At 1100 oC severe out-diusion of Co and W from the substrate occurs, and the lms recrystallize into c-TiN and w-AlN. The single layer Hf-Al-Si-N and multilayer Hf-Al-Si-N/HfN lms were grown on Si(001) substrates from a single Hf0:60Al0:20Si0:20 alloy target in an N2/Ar atmosphere. The composition and nanostructure of the lms was controlled during growth by independently varying the ion energy (Ei) and the ion-to-metal flux ratio (Ji=JMe). With Ji/JMe=8, the nanostructure and composition of the lms changes from x-ray amorphous with a Hf content of 0.6, to an amorphous matrix with encapsulated nanocrystals with 0.66≤Hf≤0.84, to nanocrystalline with 0.96≤Hf≤1.00, when increasing Ei from 15 to 65 eV. Varying Ji=JMe with Ei=13 eV yields electron-diraction amorphous lms at substrate temperatures of 100 oC. Hf-Al-Si-N/HfN multilayers with periods Λ=2-20 nm exhibit enhanced fracture toughness compared to polycrystalline VN, TiN, and Ti0:5Al0:5N reference samples; multilayer hardness values increase from 20 GPa with Λ=20 nm to 27 GPa with Λ=2 nm. ̴
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19

Choi, Francis C. "Growing a healthy church the concept and proposed training program of natural church development /". Online full text .pdf document, available to Fuller patrons only, 2000. http://www.tren.com.

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20

Garcia, Sharon Louise. "THE IMPACT OF NATURAL DISASTERS ON ECONOMIC GROWTH: A STUDY OF MEXICO AND CENTRAL AMERICA". Lexington, Ky. : [University of Kentucky Libraries], 2002. http://lib.uky.edu/ETD/ukyagec2002t00032/00Garcia.pdf.

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Thesis (M.S.)--University of Kentucky, 2002.
Title from document title page. Document formatted into pages; contains ix, 150 p. : ill. Includes abstract. Includes bibliographical references (p. 148-149).
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21

Malkani, Anum. "From Riches to Rags: The Political Economy of the Natural Resource Curse". Scholarship @ Claremont, 2011. http://scholarship.claremont.edu/cmc_theses/142.

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The natural resource curse paradox has given rise to a wide range of explanations, which look at the economic, social and political characteristics of resource-rich countries. This paper focuses on the political economy of natural resources and finds that controlling for sociopolitical factors eliminates the natural resource curse. The analysis then turns to these sociopolitical factors and examines the significant, complex and varied effects of democratization on economic growth in general, as well as in resource-rich countries in particular. I conclude that the type of institutions needed for economic development in resource-rich countries are not specific to either democratic or autocratic systems, but are equally likely to be adopted by either regime, so that no one ideology is more suitable than the other. A corollary to this, however, is the case of weak democracies or low democratization levels. Such states are unable to adopt the necessary strategies and institutions and, thus, pose the greatest threat to economic growth in resource-rich countries. On the other hand, highly autocratic systems in resource-rich countries, such as those in Bahrain and UAE, or perfectly democratic systems, such as those in Norway and Iceland, utilize resources more efficiently for economic development.
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22

Khattak, Asif. "Natural variation in Arabidopsis thaliana growth in response to ambient temperatures". Thesis, University of East Anglia, 2014. https://ueaeprints.uea.ac.uk/48817/.

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Temperature is one of the most important abiotic environmental regulators of plant growth and development. The temperature-dependent elongation of the Arabidopsis thaliana hypocotyls (seedling stems) is a well-characterised environmental response. The aim of this study was to identify allelic variants underlying Quantitative Trait Loci (QTL) responsible for the natural genetic variation of hypocotyl length in response to ambient temperatures. The Arabidopsis thaliana accessions were phenotyped for hypocotyl length at 12°C, 17°C, 22°C and 27°C ambient temperature environments and substantial genetic variation was established. This facilitated a forward genetic approach by performing a QTL analysis to identify the genetic basis of thermal sensitivity. Firstly, fine-mapped QTL were identified for hypocotyl length in response to different temperatures. SMALL AUXIN UPREGULATED RNA 38 (SAUR38) is a novel candidate gene for a QTL. Another major-effect QTL ‘Temp22.2’ was also identified which harbours the candidate gene PHYTOCHROME B (PHYB). Secondly, fine-mapped ‘Environmental QTL’ were also discovered for the genotype by environment (G x E) interaction. PHYTOCHROME D (PHYD) is a candidate for a temperature-responsiveness QTL. For QTL cloning, functional characterisation of SAUR38 and PHYB was carried out by knockout analysis and transgenic allelic complementation. The results showed that SAUR38 controlled natural variation in the Tsu-0 accession by increasing elongation. The PHYB alleles of Ct-1, Sf-2 and Col-0 accessions explain the Temp22.2 QTL. Ct-1 and Sf-2 alleles are positive regulators increasing elongation, whereas Col-0 allele is a negative regulator. Temp22.2 QTL was cloned and novel alleles were discovered revealing the molecular basis of quantitative variation in hypocotyl length in response to temperature.
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23

Kalish, Alexander P. "The Effect of Natural Disasters on Volunteerism". Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/cmc_theses/916.

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The power of natural disasters to significantly and drastically alter the lives of the people they touch is vast, and the response rate of the provided aid can be the difference between a successful recovery and not. This study examines the relationship between natural disasters and volunteerism. The analysis makes use of panel data measurements on volunteer rate and volunteer hours per resident as well as FEMA measurements of major natural disasters from 2005 – 2012. I find that states that experience a natural disaster in the current year experience a significant and positive increase in volunteer rate in the year following the disaster. The findings highlight the importance of policy focused on harnessing volunteer labor in the wake of natural disasters.
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24

Robinson, R. Mark. "An evaluation and implementation of the natural church development survey". Theological Research Exchange Network (TREN), 2005. http://www.tren.com.

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25

Brousseau, Jennifer Peterson. "Growth of natural phytoplankton populations of Wilson Bay : a nutrient bioassay approach /". Electronic version, 2005. http://dl.uncw.edu/etd/2005/brousseauj/jenniferbrousseau.html.

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26

Hooper, Emma. "Essays on international finance and sustainable growth in natural resource rich countries". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM2027/document.

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Les questions de croissance durable mêlées aux enjeux d’accès aux marchés financiers internationaux des pays riches en ressources naturelles ont souvent été occultées dans la littérature économique. Or, ces enjeux s’avèrent de plus en plus présents dans le débat public face à la baisse récente des prix du pétrole. Cette thèse tente de mieux comprendre comment des économies dépendantes de leur production de ressources épuisables gèrent leur dette externe en vue d’une croissance soutenable dans le long-terme et comment les marchés financiers perçoivent le risque souverain lors de l’émission de leur dette. Pour y répondre, elle recourt à de la modélisation dynamique, à travers un cadre théorique, ainsi qu’à des études économétriques. Elle contribue à la littérature en intégrant de nouvelles dimensions, comme l’ouverture financière dans un modèle de croissance avec des ressources épuisables, modèles qui jusque-là étaient étudiés sous la forme d'économies fermées. Par ses analyses empiriques, elle prend en compte la notion de volume à travers l’étude des réserves de pétrole et de gaz. Les principaux résultats sont que l'ouverture financière ne permet pas d’avoir une croissance soutenable à taux d’intérêt constant, mais la consommation peut croître un temps lorsque le taux d’intérêt est endogène à la dette du pays. Les réserves de pétrole et de gaz ont un effet significatif sur les spreads souverains. La thèse n'élude pas pour autant la question des prix, puisqu'elle montre que les rendements et la volatilité des prix du pétrole sont des déterminants significatifs des CDS du Venezuela, alors que l'effet des prix se répercute à travers le canal du taux de change pour la Russie
The relationship between sustainable growth and international financial market access in natural resource rich countries has been overlooked in the economic literature. However, those issues have become more present in the public debate with the recent drop in oil prices. This thesis tries to better understand how natural resource dependent economies can deal with their external debt and how financial markets view this sovereign risk. To address those issues, this dissertation refers to dynamic optimization, as well as econometric studies. It contributes to the natural resource literature by including new dimensions, such as financial openness in a growth model with exhaustible resources, contrary to most growth models which are studied as closed economies. Concerning its empirical applications, this thesis takes into account natural resource stocks, through oil and gas reserves, whereas most of the empirical literature focuses on the natural resource price dimension. This price issue is also part of the analysis, especially with oil price returns and oil price volatility. The main results are that long-term sustainability is not feasible with a constant interest rate, but the consumption growth rate can be positive in the case of a debt elastic interest rate, before declining in the long-term. It is also shown that oil and gas reserves have a significant impact on sovereign spreads. Moreover, oil price returns are significant determinants of Venezuela's Credit Default Swaps (CDS), contrary to the case of Russia, where oil prices seem to impact CDS spreads through the exchange rate canal
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27

Veisi, Mohsen. "Essays on the links between natural resources, corruption, taxation and economic growth". Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/essays-on-the-links-between-naturalresources-corruption-taxation-andeconomic-growth(a839015d-f21e-4dad-bb0c-8ea96036512c).html.

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This thesis studies the poor development performance of resource-rich developing economies, known as the resource curse. In the first chapter we provide a comprehensive literature review of the topic and the channels through which resource abundance can result in the resource curse. Issues of corruption and governance have been emphasised to be the main driver of the resource curse. This has been illustrated by a negative relationship between resource abundance and corruption control in the literature. However, there is a gap in how natural resources facilitate corruption. In the second chapter, using empirical analysis, we study the role of taxation in the relationship between natural resources and corruption. Taxation is usually seen as a social contract between citizens and government -- people pay taxes and in return they hold their government accountable for efficient allocation of their taxes. Resource abundance shifts the reliance of government from tax incomes to resource rents. People therefore, have no sustainable mechanism to hold their government responsible for corruption and wrongdoings inside public institutions. Using different econometric methods, Pooled OLS, Fixed Effects and 3SLS, our results show that natural resource revenues crowd out incomes from tax revenues. Meanwhile, taxation has a positive and significant impact on the control of corruption throughout our analysis. The results suggest that resource-rich developing countries should invest in building their tax systems to increase their non-resource tax revenues. This will increase state capacity and demand for accountability in the public sector among citizens and hence decreases corruption. Related to our second chapter, in the third chapter we study a cash transfer programme, known as oil-to-cash, which has gained support as a tool to re-establish taxation and fight corruption. Under such a plan, resource revenues are distributed directly among the public and then each citizen is taxed optimally. Through this, government relies directly and fully on its citizens for its income. Hence, taxation is reinstated and the social contract is revived. Within a general equilibrium model we show how this happens and what the implications are of the oil-to-cash programme for economic growth. Our results clearly show how corruption results in a resource curse. Furthermore, the model explains the variation that is seen in the degree of the resource curse across countries. The study also analyses the practical barriers of the oil-to-cash plan. The study suggests that parallel to (or even prior to) such a plan countries need to invest in building their tax system and increasing their administrative capacities.
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28

Fonseca, Mariana Ribeiro da Silva Lopes da. "Economic rents, institutions and growth: international aid and natural resources: a comparative analysis". Master's thesis, NSBE - UNL, 2012. http://hdl.handle.net/10362/9603.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics
The aim of this study is to investigate to what extent foreign aid rents and natural resource rents can be compared with respect to their impact on economic growth. For this purpose, the direct impact of both economic rents on GDP growth, as well as their impact conditional on the quality of the institutional environment is assessed in cross-country and panel contexts. A natural resource curse is indeed identified in countries with poor institutional quality, however results regarding the impact of international aid rents are ambiguous.
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29

Leite, Anna Olimpia de Moura. "Endogeneidade da taxa natural de crescimento". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/12/12138/tde-30012013-200904/.

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De acordo com León-Ledesma and Thirlwall (2002), o presente trabalho se propõe a testar a endogeneidade da taxa natural de crescimento para um conjunto amplo de países, no sentido do crescimento de longo prazo ser determinado pela demanda. Econometricamente, a principal hipótese a ser testada é a presença de não linearidade na Lei de Okun, que implica na existência de duas taxas naturais, cada uma correspondendo a um regime de crescimento. Utilizando dados anuais para o período de 1980 a 2007 e dados trimestrais para o intervalo entre 1980 e 2011, os resultados corroboram a hipótese de endogeneidade quando aplicada a metodologia proposta por LLT. Esta evidência se repete ao definir exogenamente os regimes de crescimento pelos métodos de Markov-Switching e threshold autoregressive regression (TAR) para os dados anuais, no entanto, para os dados trimestrais há indicações de endogeneidade e exogeneidade da taxa natural de crescimento.
Following León-Ledesma and Thirlwall (2002), this master\'s thesis aims to examine the sensitivity of the natural growth rate to the actual growth rate for a broad set of countries, based on demand-led growth theory. The main hypothesis being tested is the presence of non-linearities in Okun\'s Law, which means the existence of two natural growth rates, each corresponding to a growth regime. Using annual data over the period 1980-2007 and quarterly data over the period 1980-2011, the results support the idea that natural growth rate is dependent of the actual growth rate when applying LLT\'s methodology. This evidence repeats when establishing exogenously the regimes of growth by using Markov-Switching and threshold autoregressive regression (TAR) for the annual data, however for quarterly data this is less straightforward, having indication of endogenous and exogenous natural growth rate.
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30

Xuan, Wei. "Lung function growth and natural history of asthma in adolescence and young adulthood". Thesis, The University of Sydney, 2003. https://hdl.handle.net/2123/27925.

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The growth of lung function during adolescence and young adulthood is a complex stage and there are a few questions that remain unanswered. For instance, it is not known whether peak growth in lung function occurs at the same time as peak growth in height. It is also not clear whether growth in lung function ceases at the same age as somatic growth. Normal values of lung function are usually derived from cross-sectional studies using height, age and gender as predictors. However, these reference values do not incorporate the information of previous lung function and growth in height in predicting subsequent development of lung function. Furthermore, lung function growth and decline is a life-Iong cumulative phenomenon and the level of lung function at any point in time may reflect factors that have influenced the growth and decline in lung function many years previously. Although many children with asthma may have a remission as they grow and other children who did not have asthma may develop asthma in adult life, we have very limited knowledge about the factors that influence the onset and prognosis of asthma during adolescence and young adulthood.
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31

Pearson, Audrey F. "Natural disturbance patterns in a coastal temperate rain forest watershed, Clayoquot Sound, British Columbia /". Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5513.

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32

Ramos, Flavio Nunes. "Regeneração natural e crescimento de individuos não reprodutivos de Enterolobium glaziovii Bentham (Minosacea)". [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315728.

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Orientador: Flavio Antonio Maes dos Santos
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Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O objetivo deste estudo foi conhecer a regeneração das plântulas e jovens de Enterolobium glaziovii ao redor dos adultos. Esta espécie é uma árvore de dossel, descídua, e os seus adultos apresentam baixa densidade. Esse estudo foi realizado no estado do Rio de Janeiro, Brasil, em quatro parcelas circulares com 30 m de raio, tendo um indivíduo reprodutivo de E. glaziovii no centro de cada uma. Em todas as parcelas, valores de cobertura de dossel e graus de declividade, a chuva de frutos de E. glaziovii, o recrutamento de novos indivíduos, o padrão espacial, o crescimento e a sobrevivência de jovens coespecíficos, foram estimados anualmente de 1996 a 1999. Houve diferenças na topografia em cada parcela, apesar de todas as parcelas estarem em terreno inclinado. Os indivíduos jovens de E. glaziovii se encontravam sob alta cobertura de dossel (> 80%). O tamanho e a arquitetura da copa das plantas parentais e a inclinação do terreno influenciam a distribuição espacial dos frutos e jovens de E. glaziovii. O crescimento dos jovens de E. glaziovii é afetado negativamente pela densidade de coespecíficos, enquanto que o efeito da planta parental parece não ser importante. As plântulas desta espécie são capazes de sobreviver e crescer em uma grande amplitude de sombreamento por pelo menos 6 meses, mas apresentam maior incremento de altura em ambientes com mais de 80% de cobertura. E. glaziovii apresenta características de espécie tolerante a sombra. Essa espécie é capaz de geminar, se estabelecer, crescer e sobreviver em ambientes pouco iluminados. A taxa anual de mortalidade de indivíduos pequenos foi significativamente maior do que as taxas dos indivíduos médios e grandes. Não houve diferença entre o número de recrutamento observado e esperado tanto embaixo e fora da copa da planta parental, como em parcelas com alta e baixa densidade de frutos coespecíficos. A taxa de mortalidade não foi afetada embaixo da copa da planta parental nem em parcelas com alta densidade de jovens. Portanto, os resultados parecem indicar que os processos ocorrendo na escala espacial e temporal deste estudo não explicam a baixa densidade de adultos de E. glaziovii. Provavelmente, os processos que promovem o esparso padrão espacial dos adultos devem ocorrer em uma maior escala espacial e / ou temporal
Abstract: The purpose of this study was to know how was the regeneration pattem of Enterolobium glaziovii offspring around reproductive ones. This is a canopy and deciduous species and its adults present low density. The study was carried out in four circular plots of 30 m of radius, centered by a reproductive tree of E. glaziovii in Rio de Janeiro State, Brazil. From alI the plots the folIowing estimates were made: canopy coverage values and the declivity degrees, as welI as the E. glaziovii seed shadow, recruitment of new individuaIs, its spatial pattem, its growth, and the survival of its offspring, were estimated yearly from 1996 to 1999. Although alI the studied plots were situated on slope areas, there were differences in topography in each plot. E. glaziovii offspring were under high canopy coverage values (> 80%). The size and architecture of the parental crown and the slope influence the spatial pattem of E. glaziovii ftuit and offspring. Its growth is negatively affected by conspecific density, while the parental effect is not important to it. Seedlings of this species are capable of survive and grow in a broad range of shade levels, at least for 6 months, but they present greater height increments at environments of >80% of shade. E. glaziovii presents several characteristics of a shade-tolerant, "non-gap" species. It is capable to germinate, establish, growth and survive Ín a low light environment. Small individuaIs presented higher annual mortality rate than medium and large ones. There was no significant difference between the recruitment number expect and observed both under and outside of the parental crown and in plots with high and low density of conspecific fruit. The annual mortality rate of offspring was not affected either by offspring density or under parental crown. Therefore, It seems that the processes occurring at spatial and temporal scale of this study do not explain the low density of the E. glaziovii adults. Probably, the processes that explain the sparse spatial pattern of its adults might be occurring in a larger spatial and / or temporal scale
Mestrado
Mestre em Ecologia
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33

Yakushin, Alexander. "Ecology and morphology of selected diatom species in the genus Aulacoseira". Thesis, University of Ulster, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326314.

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Kiger, Amber A. "Changing Bacterial Growth Efficiencies across a Natural Nutrient Gradient in an Oligotrophic Estuary". FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1758.

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Recent studies have characterized coastal estuarine systems as important components of the global carbon cycle. This study investigated carbon cycling through the microbial loop of Florida Bay by use of bacterial growth efficiency calculations. Bacterial production, bacterial respiration, and other environmental parameters were measured at three sites located along a historic phosphorus-limitation gradient in Florida Bay and compared to a relatively nutrient enriched site in Biscayne Bay. A new method for measuring bacterial respiration in oligotrophic waters involving tracing respiration of 13C-glucose was developed. The results of the study indicate that 13C tracer assays may provide a better means of measuring bacterial respiration in low nutrient environments than traditional dissolved oxygen consumption-based methods due to strong correlations between incubation length and δ13C values. Results also suggest that overall bacterial growth efficiency may be lower at the most nutrient limited sites.
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35

Iji, Paul Ade. "Natural development and dietary regulation of body and intestinal growth in broiler chickens". Title page, contents and summary only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phi25.pdf.

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Corrigenda inserted behind title page. Bibliography: leaves 275-306. The pattern of body growth and intestinal development of an Australian strain of broiler chicken, the Steggles x Ross (F1) in response to different diets was studied. Five experiments were designed to examine the pattern of growth and mechanisms involved. In four other experiments, the mechanisms underlying the gross response of the broiler chicks to dietary ingredients, anti-nutritive factors and growth enhancers were examined. Results indicated that a rapid development of the small intestine preceded significant overall body growth. Body growth would, however, depend more on the various physiological events such as those related to mucosal growth and renewal, digestive enzyme function, and nutrient transport. Some of the differences observed in productivity of broiler chickens on different diets were traced to events at the intestinal level.
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36

Hogan, Holly Ann. "Avian assemblages in natural and second-growth balsam fir forests in Western Newfoundland /". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq23145.pdf.

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Agboraw, Efundem. "Consequences of natural resource constraint on global growth : evidence from the financial sector". Thesis, Anglia Ruskin University, 2016. http://arro.anglia.ac.uk/701715/.

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An investigation and evaluation of the risks involved with resource constraints on global growth, with evidence from the finance sector. This is part of the GRO (Global Resource Observatory) project at the GSI, whose main project aim is to investigate how the scarcity of finite resources will impact global social and political fragility in the short term. This particular research focuses on how the scarcity of these finite resources will impact on the financial sector especially through investments, insurance, pension schemes and banking activities. The finance sector under investigation is the UK finance sector, considered to have one of the most globalised economies worldwide. The resources which were analysed were food, oil and energy/gas. The reason for the selection of food, oil and energy/gas prices is the volatility of its prices during the past decades and its high rate of fluctuations in its price in the last decade. A quantitative analysis is carried out using regression analysis of over 11 models with different combinations of resource and finance variables and a Granger causality analysis. Results show that resources only significantly affect the finance sector holding GDP constant, with exceptions where food and gas prices significantly affect bank variables even with the inclusion of GDP. The Granger causality analysis shows a couple of 1 and 3 year unidirectional relationships between some finance variables which could indicate the possibility of systemic risks in the finance sector caused by resource scarcity.
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Agboraw, Efundem. "Consequences of natural resource constraint on global growth: evidence from the financial sector". Thesis, Anglia Ruskin University, 2016. https://arro.anglia.ac.uk/id/eprint/701715/1/Agboraw_2016.pdf.

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An investigation and evaluation of the risks involved with resource constraints on global growth, with evidence from the finance sector. This is part of the GRO (Global Resource Observatory) project at the GSI, whose main project aim is to investigate how the scarcity of finite resources will impact global social and political fragility in the short term. This particular research focuses on how the scarcity of these finite resources will impact on the financial sector especially through investments, insurance, pension schemes and banking activities. The finance sector under investigation is the UK finance sector, considered to have one of the most globalised economies worldwide. The resources which were analysed were food, oil and energy/gas. The reason for the selection of food, oil and energy/gas prices is the volatility of its prices during the past decades and its high rate of fluctuations in its price in the last decade. A quantitative analysis is carried out using regression analysis of over 11 models with different combinations of resource and finance variables and a Granger causality analysis. Results show that resources only significantly affect the finance sector holding GDP constant, with exceptions where food and gas prices significantly affect bank variables even with the inclusion of GDP. The Granger causality analysis shows a couple of 1 and 3 year unidirectional relationships between some finance variables which could indicate the possibility of systemic risks in the finance sector caused by resource scarcity.
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39

Rodrigues, Carla Sofia Caniçais. "Epigenetic modifications associated with intrauterine growth restriction". Dissertação, 2017. https://hdl.handle.net/10216/110639.

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Santos, João Pedro Ribeiro dos. "Use of environmental bacteria as plant growth promoters". Dissertação, 2018. https://hdl.handle.net/10216/121245.

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Santos, Marino Costa. "Characterization and Biotechnological Applications of Plant Growth Promoting Bacteria". Dissertação, 2020. https://hdl.handle.net/10216/132003.

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42

Fernandes, Helena Raquel dos Santos. "Evaluation of protein requirements for juvenile growth and effect of dietary protein levels on post-juvenile growth and reproduction of zebrafish (Danio rerio)". Dissertação, 2014. https://repositorio-aberto.up.pt/handle/10216/78351.

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Rodrigues, Carla Sofia Caniçais. "Epigenetic modifications associated with intrauterine growth restriction". Master's thesis, 2017. https://hdl.handle.net/10216/110639.

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44

Pinto, Lourenço de Oliveira Coelho e. Ramos. "Effects of dietary creatine supplementation in gilthead seabream (Sparus aurata) muscle growth". Master's thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/82424.

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Pinto, Lourenço de Oliveira Coelho e. Ramos. "Effects of dietary creatine supplementation in gilthead seabream (Sparus aurata) muscle growth". Dissertação, 2015. https://repositorio-aberto.up.pt/handle/10216/82424.

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Santos, João Pedro Ribeiro dos. "Use of environmental bacteria as plant growth promoters". Master's thesis, 2018. https://hdl.handle.net/10216/121245.

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Costa, Ana Rita Pinto. "Dissecting the role of profilin-1 in axon formation, growth and regeneration". Dissertação, 2014. https://repositorio-aberto.up.pt/handle/10216/89178.

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Marques, Joana Beatriz Antunes Moreira Carvalho. "Exploring the role of Profilin 1 in axon formation, growth and regeneration". Dissertação, 2016. https://hdl.handle.net/10216/90974.

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Santos, Marino Costa. "Characterization and Biotechnological Applications of Plant Growth Promoting Bacteria". Master's thesis, 2020. https://hdl.handle.net/10216/132003.

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Mendes, Raquel Albuquerque Simões Baeta. "Modulating actin dynamics during axon growth and regeneration: the role of profilin-1". Dissertação, 2015. https://repositorio-aberto.up.pt/handle/10216/81327.

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