Dans la péninsule du Cap Bon, située au Nord Est de la Tunisie, le boisement des dunes de Menzel<br />Belgacem constitue l'une des premières tentatives de reconstitution de la forêt sous le protectorat<br />français. Depuis 1930, les sables connaissent une stabilisation progressive et, aujourd'hui, la<br />nouvelle forêt a pris le dessus sur les accumulations dunaires. La forêt de Dar Chichou, de plus de<br />6000 ha d'un seul tenant, représente un remarquable exemple de forêt dunaire méditerranéenne.<br />L'étude entreprise cherche avant tout à réaliser un bilan des interventions menées par les services<br />forestiers depuis le début du XXème siècle. L'approche adoptée repose sur l'utilisation de données<br />issues de télédétection, confrontées à des relevés de terrain, pour la réalisation d'une carte des unités<br />paysagères.<br />La région Nord du Cap Bon, où l'empreinte du domaine littoral est omniprésente, se caractérise par<br />une évolution très rapide du milieu naturel et par d'importantes transformations paysagères. Les<br />aménagements en cours sont nombreux et les attentes de la société y sont très pressantes et souvent<br />contradictoires. Ainsi notre étude tentera de participer à l'analyse des changements qui ont affecté<br />les caractéristiques paysagères de la région. La comparaison de données géoréférencées multidates<br />permet de suivre l'évolution de l'espace rural dans le nord du Cap Bon depuis les années 1900. Elle<br />montre une modification sensible des paysages qui s'illustre, en particulier, par la mise en forêt<br />progressive de l'importante écharpe dunaire de Dar Chichou.<br />Nous tenterons de démontrer l'intérêt d'une telle méthodologie pour parvenir à la proposition de<br />nouveaux modes de gestion capables d'intégrer les diverses fonctions du milieu forestier.

<p>The aim of this essay is to give the reader an idea of how the European agricultural policies have developed, in regard of sustainable development, since Sweden became a member in the union 1995. The main aspect that’s been investigated is the issues regarding sustainable development and how the issues regarding the ecological farming methods have been dealt with. My research questions are:</p><p>- How has the European environment- and agricultural politics changed since Sweden</p><p>joined the union in 1995?</p><p>- What consequences have the changes had for ecological farming?</p><p>The answers to the stated questions are that there have been several treaties in the field of environmental development of the agricultural policy, starting with the Maastricht treaty and ends up with the European Action Plan for Organic Food and Farming. Since there are economical aid to back up the decisions there have been some restructuring of the farming policies in the way that makes it’s possible to produce ecological products even if that’s more expensive than the regular actions.</p>

Texte remanié de: Thèse de doctorat--Histoire--Paris--EHESS, 2001. / Glossaire. IFAS = Institut français d'Afrique du Sud.

Disputats. Rheinische Friedrick-Wilhelms-Universität, 2002. / Haves kun i elektronisk udg.

Since 2006 California has been pursuing the most ambitious climate change policy in the United States, implementing a suite of greenhouse gas reduction measures ranging from automobile refrigerant disposal rules to clean energy standards for electric power utilities. The most significant of these measures is the creation of a cap‐and‐trade program. Through this program, regulators seek to create a knowable price‐signal to incentivize emissions reductions among polluters. Using a suite of ethnographic methods, this dissertation looks at the people, ideas, and institutions that have been mobilized in the creation of California’s cap‐and‐ trade program. Substantively, the dissertation engages with three key aspects of the program. First, the way that economic theory is deployed in the creation of the rules of exchange, and how that theory is made to take a compromised but still structuring role in light of the political pressures on regulators in writing the rules of exchange in financial representations of greenhouse gases. Second, the dissertation examines the diverse values, economic and non‐economic, in play during the creation of financial representations of greenhouse gases; and third, the environmental and social justice ramifications of structuring an emissions reduction program around the motivation of doing so at the lowest possible cost to polluters. Theoretically, this dissertation is informed by political ecology on the commodification of nature, commodity theory drawn from economic geography and political economy, and sociological theories of economic practice primarily originating from the social studies of finance. The conclusion of the dissertation is that the result of countless hours of work by regulators and their interlocutors is a suite of market‐like mechanisms that ultimately function more like the administrative tool that environmental markets’ early advocates envisioned rather than the full‐blown financialization of the atmosphere, though with potentially detrimental environmental impacts for vulnerable communities.

In many wireless devices, antennas occupy the majority of the overall size. As compact device sizes become a greater focus in industry, the demand for small antennas escalates. In this thesis, detailed investigations on the design of a planar meandered line antenna with truncated ground plane and 3D dipole antenna at 2.4 GHz (ISM band) are presented. The primary goal of this research is to develop small, low coast, and low profile antennas for wireless sensor applications. The planar meandered line antenna was designed based on a study of different miniaturization techniques and a study of the ground plane effect. The study of the ground plane effect proved that it has a pivotal role on balancing the antenna current. The study of the miniaturization process proved that it affects directly the gain, bandwidth, and efficiency. The antenna efficiency and gain were improved using the truncated ground plane. This antenna has a measured gain of -0.86 dBi and measured efficiency of 49.7%, making it one of the efficient and high gain small antennas. The 3D dipole antenna was designed using a novel method for efficiently exploiting the available volume. This method consists of fabricating the dipole on a cube configuration with opening up the internal volume for other uses. This antenna was tested, and it was found that this antenna has good radiation characteristics according to its occupied volume. Ka of this antenna is 0.55, its measured gain is 1.69 dBi with 64.2% measured efficiency. Therefore, this design is very promising in low-power sensing applications. A Wheeler Cap was designed for measuring the efficiency and the 3-antenna method was used for measuring the designed antennas gain.

In recent decades, climate change has become one of the most crucial challenges for humanity. Climate change has a direct correlation with global warming, caused mainly by the green house gas emissions (GHG). The Environmental Protection Agency in the U.S. (EPA) attributes carbon dioxide to account for approximately 82\% of the GHG emissions. Unfortunately, the energy sector is the main producer of carbon dioxide, with China and the U.S. as the highest emitters. Therefore, there is a strong (positive) correlation between energy production, global warming, and climate change. Stringent carbon emissions reduction targets have been established in order to reduce the impacts of GHG. Achieving these emissions reduction goals will require implementation of policies like as cap-and-trade and carbon taxes, together with transformation of the electricity grid into a smarter system with high green energy penetration. However, the consideration of policies solely in view of carbon emissions reduction may adversely impact other market outcomes such as electricity prices and consumption. In this dissertation, a two-layer mathematical-statistical framework is presented, that serves to develop carbon policies to reduce emissions level while minimizing the negative impacts on other market outcomes. The bottom layer of the two layer model comprises a bi-level optimization problem. The top layer comprises a statistical model and a Pareto analysis. Two related but different problems are studied under this methodology. The first problem looks into the design of cap-and-trade policies for deregulated electricity markets that satisfy the interest of different market constituents. Via the second problem, it is demonstrated how the framework can be used to obtain levels of carbon emissions reduction while minimizing the negative impact on electricity demand and maximizing green penetration from microgrids. In the aforementioned studies, forecasts for electricity prices and production cost are considered. This, this dissertation also presents anew forecast model that can be easily integrated in the two-layer framework. It is demonstrated in this dissertation that the proposed framework can be utilized by policy-makers, power companies, consumers, and market regulators in developing emissions policy decisions, bidding strategies, market regulations, and electricity dispatch strategies.

Strut-and-tie modeling (STM) is a versatile, lower-bound (i.e. conservative) design method for reinforced concrete structural components. Uncertainty expressed by engineers related to the implementation of existing STM code specifications as well as a growing inventory of distressed in-service bent caps exhibiting diagonal cracking was the impetus for the Texas Department of Transportation (TxDOT) to fund research project 0-5253, D-Region Strength and Serviceability Design, and the current implementation project (5-5253-01). As part of these projects, simple, accurate STM specifications were developed. This thesis acts as a guidebook for application of the proposed specifications and is intended to clarify any remaining uncertainties associated with strut-and-tie modeling. A series of five detailed design examples feature the application of the STM specifications. A brief overview of each design example is provided below. The examples are prefaced with a review of the theoretical background and fundamental design process of STM (Chapter 2). • Example 1: Five-Column Bent Cap of a Skewed Bridge - This design example serves as an introduction to the application of STM. Challenges are introduced by the bridge’s skew and complicated loading pattern. A clear procedure for defining relatively complex nodal geometries is presented. • Example 2: Cantilever Bent Cap - A strut-and-tie model is developed to represent the flow of forces around a frame corner subjected to closing loads. The design and detailing of a curved-bar node at the outside of the frame corner is described. • Example 3a: Inverted-T Straddle Bent Cap (Moment Frame) - An inverted-T straddle bent cap is modeled as a component within a moment frame. Bottom-chord (ledge) loading of the inverted-T necessitates the use of local STMs to model the flow of forces through the bent cap’s cross section. • Example 3b: Inverted-T Straddle Bent Cap (Simply Supported) - The inverted-T bent cap of Example 3a is designed as a member that is simply supported at the columns. • Example 4: Drilled-Shaft Footing - Three-dimensional STMs are developed to properly model the flow of forces through a deep drilled-shaft footing. Two unique load cases are considered to familiarize the designer with the development of such models. / text

Anthropogenic global changes are altering properties and functions of social and ecological systems at multiple spatial and temporal scales. In addition to climate change, the Peruvian Southern Andes has also experienced dramatic political and social change. This dissertation addresses the responses of plants, humans, communities and sub-national governments to the impacts of these changes. Methods from both the social and natural sciences were used at three levels: 1) on the forelands of the Quelccaya ice cap a chronosequence approach was used and 113 quadrats (1m2) sampled the vegetation covering an altitudinal range from 5113 to 4830 m.a.s.l.; 2) with the households of herders in the Quelcaya community surveys, interviews, participant observation, and archival research were employed; and 3) with the three Regional Governments (Arequipa, Cusco, and Puno) interviews with officials and stakeholders were conducted. The results show an upward displacement of the elevational limit of plants and a trend towards homogenization of vegetation. Warming climate, a shortened rainy season, and longer dry and cold spells are the most relevant impacts of climate change in the study area. Responses to these changes occur within households, supra-household units and communities, through dynamic institutions, traditional knowledge, and flexible polycentric social organization. These responses originate from path dependencies generated by human-environment interactions in the Peruvian Southern Andes. For instance, pastoralists increased livestock mobility within their pastures, created wetlands through irrigation, and introduced agriculture of bitter potatoes. The women agriculturalists modified the productive calendar to adjust agricultural tasks to changes in the rainfall regime; they replaced maize for wheat and fava bean, because these crops are more resistant to cold spells. Agro-pastoralists increase institutional water governance and demand infrastructure to improve efficient water use. Synergies between local and regional adaptive responses to climate change may be led by projects like building irrigation infrastructure and strengthening local resource governance, although there are also disjunctions that limit adaption. Local social ecological systems are adaptive and resilient to multi-scale social environmental disturbances by a malleable forging of former strategies to face change, innovation, polycentric social organization, and a dynamic institutional body that promptly response to change. / text

Significant diagonal cracking in reinforced concrete inverted-T straddle bent caps has been reported throughout the State of Texas. Many of the distressed structures were recently constructed and all have been in service for less than two decades. The unique nature of the problem prompted a more detailed look into the design and behavior of such structural components. Strut-and-tie modeling is currently recommended for design of deep (rectangular) beams, but its application to more complex structures has not been fully explored. Due to concerns with current design provisions the application of strut-and-tie modeling to inverted-T beams was investigated along with serviceability-related considerations in this dissertation. An experimental study was conducted in which thirty-three reinforced concrete inverted-T beam tests were conducted. The effects of the following variables were evaluated: ledge depth and length, quantity of web reinforcement, number of point loads, member depth, and shear span-to-depth ratio. A strut-and-tie design method proposed by Birrcher et. al (2009), initially calibrated for compression-chord loaded deep beams, was investigated. It was concluded that the strut-and-tie method was a simple and accurate design method, and it was recommended for use in inverted-T beam design. A vi recommendation was also made for the amount of minimum web reinforcement needed for strength and serviceability considerations. A simple service-load check was proposed for the purpose of limiting diagonal cracking under service loads. Finally, a chart was created to aid in the evaluation of distressed, diagonally-cracked inverted-T bent caps in the field. / text