本文延伸並修正Dornbusch (1976)的模型，據以討論匯率重整與投機性炒作的問題。我們所選取的題材為，一個原先實施固定匯率制度的國家。假設初始時，匯率固定在期初的匯率水準及所對應的長期均衡物價。經濟體系基於某種因素，民眾自我預期固定匯率制度無法繼續維持，此時刻匯率由初始的靜止狀態產生變化，理性的民眾迅速地改變其資產組合。一且面臨民眾的投機性炒作，資金外流使得國內貨幣供給數量降至門檻水準，則政府當局放棄維持固定匯率制度，允許匯率浮動。政府當局的匯率重整法則是允許匯率浮動時，當物價上升至匯率重整的物價水準，政府當局又重新將匯率釘在一個更高的水準。在此，又須假設匯率重整的匯率水準大於其物價水準，此情況的解釋為當物價上升至匯率重整的物價水準時，政府當局的貨幣貶值至少使國內商品的競爭力不低於長期均衡解。同時，本文引進貨幣學派(Monetary Approach)所主張的匯率變動的貨幣效果，強調匯率與貨幣市場的關係。來重新探討Obstfeld (1988)自我兌現(Self-fulfilling)匯率制度崩潰問題的多重解(Multiple-equilibria)現象。茲將本文所得到的主要結論，摘述如下。 　　(1)本文所討論的自我兌現匯率制度崩潰的多重解問題，實為國際金融理論中「匯率制度崩潰」的範疇，此制度更迭的時刻（匯率重整的時點）為內生變數，此一更迭時刻為模型所決定。且本文所討論的匯率制度更迭順序為，先固定匯率制度，再更迭為浮動匯率制度，再回復至固定匯率制度。 　　(2)由於引進貨幣學派所強調的緊縮銀根效果，不管是固定匯率制度還是浮動匯率制度，支出移轉效果與支出減少效果的相對大小，都是決定變數動態走勢及最後均衡解的關鍵因素。同時政府擁有外匯存底的多寡，也與自我兌現匯率制度是否崩潰息息相關。 　　(3)當支出移轉效果大於支出減少效果，自我兌現匯率制度崩潰的問題共有五個均衡解。而其均衡解決定於政府當局決定匯率重整的物價水準及擁有外匯存底的多寡。 　　(4)當支出移轉效果小於支出減少效果，亦即支出減少效果很大時，自我兌現匯率制度崩潰的問題共有二個均衡解。此二解皆無匯率重整的現象。 　　(5)在本文所分析的體制變革中，共有二次投機性炒作發生。第一次發生在固定匯率制度崩潰的時刻，第二次則發生在匯率重整的時刻。前者使外匯存底大量流失，貨幣供給數量瞬間減少。後者使外匯存底大量流入，貨幣供給數量瞬間增加。 　　由於本文將貨幣學派所主張的匯率變動的貨幣效果引進Dornbusch (1976)的模型中，支出移轉效果與支出減少效果兩個關鏈因素的相對大小，決定了經濟體系的靜止狀態條件及動態調整性質。換言之，不將緊縮銀根效果引進，回復其原設定模型，則影響經濟體系的只有貶值的支出移轉效果。支出減少效果很大時，匯率重整法則無從實施的現象也不曾出現在本文的分析中，亦即為本文與眾不同之所在。

<p>This PhD thesis, consisting of an introduction, four papers, and some supplementary results, studies the problem of finding an <i>optimal realization</i> of a given finite metric space: a weighted graph which preserves the metric's distances and has minimal total edge weight. This problem is known to be NP-hard, and solutions are not necessarily unique.</p><p>It has been conjectured that <i>extremally weighted</i> optimal realizations may be found as subgraphs of the <i>hereditarily optimal realization</i> Γ_d, a graph which in general has a higher total edge weight than the optimal realization but has the advantages of being unique, and possible to construct explicitly via the <i>tight span</i> of the metric.</p><p>In Paper I, we prove that the graph Γ_d is equivalent to the 1-skeleton of the tight span precisely when the metric considered is <i>totally split-decomposable</i>. For the subset of totally split-decomposable metrics known as <i>consistent</i> metrics this implies that Γ_d is isomorphic to the easily constructed <i>Buneman graph</i>.</p><p>In Paper II, we show that for any metric on at most five points, any optimal realization can be found as a subgraph of Γ_d.</p><p>In Paper III we provide a series of counterexamples; metrics for which there exist extremally weighted optimal realizations which are not subgraphs of Γ_d. However, for these examples there also exists at least one optimal realization which is a subgraph.</p><p>Finally, Paper IV examines a weakened conjecture suggested by the above counterexamples: can we always find some optimal realization as a subgraph in Γ_d? Defining <i>extremal</i> optimal realizations as those having the maximum possible number of shortest paths, we prove that any embedding of the vertices of an extremal optimal realization into Γ_d is injective. Moreover, we prove that this weakened conjecture holds for the subset of consistent metrics which have a 2-dimensional tight span</p>

In Chapters 1 and 2, we introduce the definition of interpolating refinable function vectors in dimension one and high dimensions, characterize such interpolating refinable function vectors in terms of their masks, and derive their sum rule structure explicitly. We study biorthogonal refinable function vectors from interpolating refinable function vectors. We also study the symmetry property of an interpolating refinable function vector and characterize a symmetric interpolating refinable function vector in any dimension with respect to certain symmetry group in terms of its mask. Examples of interpolating refinable function vectors with some desirable properties, such as orthogonality, symmetry, compact support, and so on, are constructed according to our characterization results. In Chapters 3 and 4, we turn to the study of general matrix extension problems with symmetry for the construction of orthogonal and biorthogonal multiwavelets. We give characterization theorems and develop step-by-step algorithms for matrix extension with symmetry. To illustrate our results, we apply our algorithms to several examples of interpolating refinable function vectors with orthogonality or biorthogonality obtained in Chapter 1. In Chapter 5, we discuss some possible future research topics on the subjects of matrix extension with symmetry in high dimensions and frequency-based non-stationary tight wavelet frames with directionality. We demonstrate that one can construct a frequency-based tight wavelet frame with symmetry and show that directional analysis can be easily achieved under the framework of tight wavelet frames. Potential applications and research directions of such tight wavelet frames with directionality are discussed. / Applied Mathematics

This PhD thesis, consisting of an introduction, four papers, and some supplementary results, studies the problem of finding an optimal realization of a given finite metric space: a weighted graph which preserves the metric's distances and has minimal total edge weight. This problem is known to be NP-hard, and solutions are not necessarily unique. It has been conjectured that extremally weighted optimal realizations may be found as subgraphs of the hereditarily optimal realization Γd, a graph which in general has a higher total edge weight than the optimal realization but has the advantages of being unique, and possible to construct explicitly via the tight span of the metric. In Paper I, we prove that the graph Γd is equivalent to the 1-skeleton of the tight span precisely when the metric considered is totally split-decomposable. For the subset of totally split-decomposable metrics known as consistent metrics this implies that Γd is isomorphic to the easily constructed Buneman graph. In Paper II, we show that for any metric on at most five points, any optimal realization can be found as a subgraph of Γd. In Paper III we provide a series of counterexamples; metrics for which there exist extremally weighted optimal realizations which are not subgraphs of Γd. However, for these examples there also exists at least one optimal realization which is a subgraph. Finally, Paper IV examines a weakened conjecture suggested by the above counterexamples: can we always find some optimal realization as a subgraph in Γd? Defining extremal optimal realizations as those having the maximum possible number of shortest paths, we prove that any embedding of the vertices of an extremal optimal realization into Γd is injective. Moreover, we prove that this weakened conjecture holds for the subset of consistent metrics which have a 2-dimensional tight span

Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. Topical gene therapy involves administration of the genetic material onto the surface of skin and mucosal membranes. Cationic gemini surfactants (m-s-m, where m represents the carbon atoms in the alkyl tail and s represents the carbon atoms in the spacer) are a novel category of delivery agents with especially high potential for polynucleotides. This is due to their structural versatility, ability to bind and condense DNA, and relatively low toxicity. <p>The objectives were to design, construct and characterize a cationic, non-viral gemini surfactant-based delivery system for an IFN-ã coding plasmid suitable for cutaneous gene therapy and to evaluate this novel therapeutic approach in a Tsk (tight-skin scleroderma) mouse model to determine its clinical feasibility. <p>The delivery systems were characterized by microscopy, dynamic light scattering (DLS), circular dichroism (CD) and small angle X-ray scattering (SAXS). <i>In vitro</i> gene expression was evaluated in PAM 212 keratinocyte culture. The extent of topical delivery of the plasmid using nanoparticle and nanoemulsion formulations was evaluated by measuring IFN-ã levels in CD1, IFN-ã-deficient and Tsk mice. The effect of transgene expression on collagen synthesis was evaluated in Tsk animals by real-time PCR.<p>The <i>in vitro</i> plasmidgeminilipid (PGL) system showed heterogeneous particle size (100-200 nm small particles and 300-600 nm aggregates). Electrostatic interactions between the DNA and PGL systems shifted the negative æ-potential of the DNA (-47 mV) to positive values (30-50 mV). At the same time, condensation of the DNA, and formation of Ø DNA was indicated by the increase of the overall negative signal in the CD spectra, due to the flattening of the 290 nm peak and shift of the 260 nm peak into the negative region in a structure-dependent manner. Lipid organization of the DNADOPE system, in the absence of gemini surfactants, shows hexagonal structure, while addition of gemini surfactant at +/- charge ratio of 10 caused lamellar phase organization. For short spacers (n=3-6), additional Pn3m cubic phase also appear to be present. <p><i> In vitro</i> transfection efficiency in the 12-n-12 series was found to be dependent on the length of the spacer between the two positively charged head groups, with the n=3 spacer showing the highest activity. The PGL systems with 12-3-12 and 12-4-12 led to significantly higher transgene expression compared to the other surfactants of the series. The transfection efficiency significantly correlated with the surface area occupied by one molecule (a). The effect of the tail length influenced the transfection efficiency, with longer tails being associated with higher protein expression. The highest <i>in vitro</i> transfection efficiency was recorded with the 18:1-3-18:1 surfactant (1.4±0.3 ng/5x10E4 cells). <p><i>In vivo</i>, high levels of IFN-ã expression were detected in the skin of animals treated with both nanoparticle (359±239 pg/cm2) and nanoemulsion (607±411 pg/cm2) formulations compared to topical naked DNA (136±125 pg/cm2). IFN-ã levels in the skin of animals injected with 5 ìg DNA were 256±130 pg/cm2. IFN-ã levels in the lymph nodes were higher for the nanoparticle formulation (433±456 pg/animal) compared to nanoemulsion (131±136 pg/animal) suggesting different delivery pathway of the two formulations.<p>IFN-ã expression was at high levels in the skin of Tsk mice after 4-day and 20-day treatments (472±171 and 345±276 pg/cm2). Both 4-day and 20-day treatments reduced the procollagen type I á1 mRNA levels for the topical treatment (64 and 70% reduction) and intradermal injection (58 and 72% reduction). Intercellular adhesion molecule-1 (ICAM-1) was upregulated by 50% in both topically treated and injected animals after 20-day treatment. <p>Here, it has been demonstrated that cationic gemini surfactant-based delivery systems are able to transfect epidermal cells <i>in vivo</i>, and the transgene IFN-ã expression is sufficient to cause significant reduction of collagen in an animal model of scleroderma. It has been shown for the first time that topical gene therapy is a feasible approach for the modulation of excessive collagen synthesis in scleroderma-affected skin.

Denna rapport ger förslag på olika metoder att automatiskt justera flytläget på en statiskt förankrad boj, en överblick över de processer som styr ändringen av vattennivån och en statisktisk analys på vattennivåförändringarna vid Stockholm, Kungsholmsfort och Kungsvik. Beroende på vattenivåns variation finns olika metoder för justering. Områden med små variationer av vattennivå lämpar det sig bäst utan någon som helst justering av flytläget. Områden med inte för stora tidvattensförändringar bör justeras med ett system bestående av vinsch, växellåda med en utväxling på 10 000:1, en 12 V DC motor, ett skötselfritt 12 V batteri, en luftlindad linjärgenerator och en trådtöjningsgivare. Områden med stora variationer i tidvatten behöver en avlastning för motorn i form av en fjäder och dämpare. De monteras horizontellt inuti bojen för att skyddas från den yttre miljön. Den statistiska analysen påvisade de största vattennivåändringarna vid både Kungsviks och Kungsholmsforts mätstationer, båda uppvisade ett intervall på 1,6 m mellan minimum och maximum. Kungsvik var den station med de största dagliga variationerna, detta på grund av tidvattnets påverkan i området. / This thesis gives examples of different methods of automated adjustment of floatation level for a static moored buoy, an overview of the theories behind water level change and a statistical analysis of the water level changes for Stockholm, Kungsholmsfort and Kungsvik. Depending on the range and frequency of the water level change different methods of adjustment are recommended. For areas with small changes in sea level the best choice would be no adjustment of the floatation level. Areas that are influenced by moderate tidal ranges should incorporate a system of regulation consisting of a winch, gearbox with a gear ratio of around 10,000:1, 12 V DC motor, 12 V maintenance free battery, air coiled linear generator and a strain gauge. For areas with large tidal ranges the previous system should be complimented with a horizontally mounted spring, inside the buoy, to lessen the loads on the motor. The statistical analysis found the largest extremes in water level of the three sites to be at Kungsvik and Kungsholmsfort, both exhibiting a range of almost 1.6 m. Kungsvik was the station with the largest daily variations, this is because this is the only station influenced by tidal variations.

Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. Topical gene therapy involves administration of the genetic material onto the surface of skin and mucosal membranes. Cationic gemini surfactants (m-s-m, where m represents the carbon atoms in the alkyl tail and s represents the carbon atoms in the spacer) are a novel category of delivery agents with especially high potential for polynucleotides. This is due to their structural versatility, ability to bind and condense DNA, and relatively low toxicity. <p>The objectives were to design, construct and characterize a cationic, non-viral gemini surfactant-based delivery system for an IFN-ã coding plasmid suitable for cutaneous gene therapy and to evaluate this novel therapeutic approach in a Tsk (tight-skin scleroderma) mouse model to determine its clinical feasibility. <p>The delivery systems were characterized by microscopy, dynamic light scattering (DLS), circular dichroism (CD) and small angle X-ray scattering (SAXS). <i>In vitro</i> gene expression was evaluated in PAM 212 keratinocyte culture. The extent of topical delivery of the plasmid using nanoparticle and nanoemulsion formulations was evaluated by measuring IFN-ã levels in CD1, IFN-ã-deficient and Tsk mice. The effect of transgene expression on collagen synthesis was evaluated in Tsk animals by real-time PCR.<p>The <i>in vitro</i> plasmidgeminilipid (PGL) system showed heterogeneous particle size (100-200 nm small particles and 300-600 nm aggregates). Electrostatic interactions between the DNA and PGL systems shifted the negative æ-potential of the DNA (-47 mV) to positive values (30-50 mV). At the same time, condensation of the DNA, and formation of Ø DNA was indicated by the increase of the overall negative signal in the CD spectra, due to the flattening of the 290 nm peak and shift of the 260 nm peak into the negative region in a structure-dependent manner. Lipid organization of the DNADOPE system, in the absence of gemini surfactants, shows hexagonal structure, while addition of gemini surfactant at +/- charge ratio of 10 caused lamellar phase organization. For short spacers (n=3-6), additional Pn3m cubic phase also appear to be present. <p><i> In vitro</i> transfection efficiency in the 12-n-12 series was found to be dependent on the length of the spacer between the two positively charged head groups, with the n=3 spacer showing the highest activity. The PGL systems with 12-3-12 and 12-4-12 led to significantly higher transgene expression compared to the other surfactants of the series. The transfection efficiency significantly correlated with the surface area occupied by one molecule (a). The effect of the tail length influenced the transfection efficiency, with longer tails being associated with higher protein expression. The highest <i>in vitro</i> transfection efficiency was recorded with the 18:1-3-18:1 surfactant (1.4±0.3 ng/5x10E4 cells). <p><i>In vivo</i>, high levels of IFN-ã expression were detected in the skin of animals treated with both nanoparticle (359±239 pg/cm2) and nanoemulsion (607±411 pg/cm2) formulations compared to topical naked DNA (136±125 pg/cm2). IFN-ã levels in the skin of animals injected with 5 ìg DNA were 256±130 pg/cm2. IFN-ã levels in the lymph nodes were higher for the nanoparticle formulation (433±456 pg/animal) compared to nanoemulsion (131±136 pg/animal) suggesting different delivery pathway of the two formulations.<p>IFN-ã expression was at high levels in the skin of Tsk mice after 4-day and 20-day treatments (472±171 and 345±276 pg/cm2). Both 4-day and 20-day treatments reduced the procollagen type I á1 mRNA levels for the topical treatment (64 and 70% reduction) and intradermal injection (58 and 72% reduction). Intercellular adhesion molecule-1 (ICAM-1) was upregulated by 50% in both topically treated and injected animals after 20-day treatment. <p>Here, it has been demonstrated that cationic gemini surfactant-based delivery systems are able to transfect epidermal cells <i>in vivo</i>, and the transgene IFN-ã expression is sufficient to cause significant reduction of collagen in an animal model of scleroderma. It has been shown for the first time that topical gene therapy is a feasible approach for the modulation of excessive collagen synthesis in scleroderma-affected skin.

The supply and demand situation is crucial for the oil and gas industry during the first half of the 21st century. For the future, we will see two trends going in opposite directions: a decline in discoveries of conventional oil and gas reservoirs and an increase in world energy demand. Therefore, the need to develop and produce unconventional oil and gas resources, which encompass coal-bed methane, gas-shale, tight sands and heavy oil, will be of utmost importance in the coming decades. In the past, large-scale production from tight gas reservoirs occurred only in the U.S. and was boosted by both price incentives and well stimulation technology. A conservative study from Rogner (1997) has shown that tight gas sandstone reservoirs would represent at least over 7,000 trillion cubic feet (Tcf) of natural gas in place worldwide. However, most of the studies such as the ones by the U.S. Geological Survey (U.S.G.S.) and Kuuskraa have focused on assessing the technically recoverable gas resources in the U.S. with numbers ranging between 177 Tcf and 379 Tcf. During the past few decades, gas production from tight sands field developments have taken place all around the world from South America (Argentina), Australia, Asia (China, Indonesia), the Russian Federation, Northern Europe (Germany, Norway) and the Middle East (Oman). However, the U.S. remains the region where the most extensive exploration and production for unconventional gas resources occur. In fact, unconventional gas formations accounted for 43% of natural gas production and tight gas sandstones represented 66% of the total of unconventional resources produced in the U.S. in 2006. As compared to a conventional gas well, a tight gas well will have a very low productivity index and a small drainage area. Therefore, to extract the same amount of natural gas out of the reservoir, many more wells will have to be drilled and stimulated to efficiently develop and produce these reservoirs. Thus, the risk involved is much higher than the development of conventional gas resources and the economics of developing most tight gas reservoirs borders on the margin of profitability. To develop tight gas reservoirs, engineers face complex problems because there is no typical tight gas field. In reality, a wide range of geological and reservoir differences exist for these formations. For instance, a tight gas sandstone reservoir can be shallow or deep, low or high pressure, low or high temperature, bearing continuous (blanket) or lenticular shaped bodies, being naturally fractured, single or multi-layered, and holding contaminants such as CO2 and H2S which all combined increase considerably the complexity of how to drill a well. Since the first tight gas wells were drilled in the 1940's in the U.S., a considerable amount of information has been collected and documented within the industry literature. The main objective of this research project is to develop a computer program dedicated to applying the drilling technologies and methods selection for drilling tight gas sandstone formations that have been documented as best practices in the petroleum literature.

Various models featuring horizontal wells with multiple induced fractures have been proposed to characterize flow behavior over time in tight gas and shale gas systems. Currently, there is little consensus regarding the effects of non-ideal fracture geometries and coupled primary-secondary fracture interactions on reservoir performance in these unconventional gas reservoirs. This thesis provides a grid construction tool to generate high-resolution unstructured meshes using Voronoi grids, which provides the flexibility required to accurately represent complex geologic domains and fractures in three dimensions. Using these Voronoi grids, the interaction between propped hydraulic fractures and secondary "stress-release" fractures were evaluated. Additionally, various primary fracture configurations were examined, where the fractures may be non-planar or non-orthogonal. For this study, a numerical model was developed to assess the potential performance of tight gas and shale gas reservoirs. These simulations utilized up to a half-million grid-blocks and consider a period of up to 3,000 years in some cases. The aim is to provide very high-definition reference numerical solutions that will exhibit virtually all flow regimes we can expect in these unconventional gas reservoirs. The simulation results are analyzed to identify production signatures and flow regimes using diagnostic plots, and these interpretations are confirmed using pressure maps where useful. The coupled primary-secondary fracture systems with the largest fracture surface areas are shown to give the highest production in the traditional "linear flow" regime (which occurs for very high conductivity vertical fracture cases). The non-ideal hydraulic fracture geometries are shown to yield progressively lower production as the angularity of these fractures increases. Hence, to design optimum fracture completions, we should endeavor to keep the fractures as orthogonal to the horizontal well as possible. This work expands the current understanding of flow behavior in fractured tight-gas and shale-gas systems and may be used to optimize fracture and completion design, to validate analytical models and to facilitate more accurate reserves estimation.

Es werden physikallische Eigenschaften von Quasikristallen anhand von quasiperiodischen Ising- und Tight-Binding-Modellen auf dem fuenfzaehligen Penrose- und achtzaehligen Amman-Beenker-Muster untersucht. Bei den Ising-Modellen wird eine graphische Hochtemperaturentwicklung der freien Energie ausgerechnet und die kritischen Parameter des ferromagnetischen Phasenueberganges abgeschaetzt. Weiterhin wird mittels eines analytischen Resultates die freie Energie auf den periodischen Approximanten quasiperiodischer Muster exakt ausgerechnet und zur Bestimmung der Verteilung komplexer (Fisher-)Nullstellen herangezogen. Letztendlich wird noch ein Ising-Modell mit einem verschiedenen, nicht-Onsager kritischen Verhalten konstruiert und untersucht. Im zweiten Kapitel werden kritische, nichtnormierbare Eigenzustaende eines quasiperiodischen Tight-Binding-Modells exakt berechnet. Es stellt sich heraus, dass die Eigenzustaende eine selbstaehnliche, fraktale Struktur aufweisen die in Details untersucht wird.