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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

On eigenvalues of the Schrödinger operator with a complex-valued polynomial potential

Alexandersson, Per January 2010 (has links)
In this thesis, we generalize a recent result of A. Eremenko and A. Gabrielov on irreducibility of the spectral discriminant for the Schroedinger equation with quartic potentials. In the first paper, we consider the eigenvalue problem with a complex-valued polynomial potential of arbitrary degree d and show that the spectral determinant of this problem is connected and irreducible. In other words, every eigenvalue can be reached from any other by analytic continuation. We also prove connectedness of the parameter spaces of the potentials that admit eigenfunctions satisfying k > 2 boundary conditions, except for the case d is even and k = d/2. In the latter case, connected components of the parameter space are distinguished by the number of zeros of the eigenfunctions. In the second paper, we only consider even polynomial potentials, and show that the spectral determinant for the eigenvalue problem consists of two irreducible components. A similar result to that of paper I is proved for k boundary conditions.
72

An Investigation of the Attractiveness and Feasibility of Introducing Temocillin to the Swedish or Scandinavian Market

Hultqvist, Lovisa, Jonsson, Cajsa, Kani, Sufyan, Regnell, Julia, Weiden, Lovisa January 2023 (has links)
Antibiotic resistance is a global health concern. Its increasing development is seemingly due to the irresponsible use of antibiotics and their availability. To ensure the correct treatment of patients and avoid unnecessary strain on the individual and society as a whole, it is vital to ensure access to both new and old antibiotics where there is a distinct need. Temocillin is an antibiotic used in the treatment of febrile UTIs. It is currently unavailable in Sweden, although being well-established and proven effective in other European countries. Hence, this report aims to investigate the introduction of temocillin to the Swedish or Scandinavian market in regards to the economic, technical, medical, and regulatory possibilities and barriers. The research is based on literature, internet, and database reviews and empirical data collection through interviews with people of expertise within the fields of antibiotic resistance and concerned aspects. This study emphasizes the great potential of introducing temocillin to Sweden. The evident conclusion drawn is that a production of the antibiotic is not possible in Sweden in the near future. Despite this, an identified supply chain in Europe can enable a role for Sweden as a distribution country. Through a performed break-even analysis, the calculated break-even point and profit margins indicated a low risk of financial loss for a MAH acting as the supplier of temocillin, such as the company Eumedica S.A.. Only 1 % of the Swedish market would have to be covered to break even, and regardless of the estimated volumes of usage upon introduction being either 50 % or 25 % of the total medical need, a profit is likely. In addition, temocillin holds a great medical and social value. However, the obvious obstacle observed is its out-dated documentation. The dossier is of the wrong format, which complicates the regulatory procedure. Thus, this needs to be taken into consideration for an introduction to be possible.
73

Bivariate C1 Cubic Spline Spaces Over Even Stratified Triangulations

Liu, Huan Wen, Hong, Don 01 December 2002 (has links)
It is well-known that the basic properties of a bivariate spline space such as dimension and approximation order depend on the geometric structure of the partition. The dependence of geometric structure results in the fact that the dimension of a C1 cubic spline space over an arbitrary triangulation becomes a well-known open problem. In this paper, by employing a new group of smoothness conditions and conformality conditions, we determine the dimension of bivariate C1 cubic spline spaces over a so-called even stratified triangulation.
74

A Phan-like theorem for orthogonal groups in even characteristic

Iverson, Nate 07 August 2010 (has links)
No description available.
75

SCENARIO CLUSTERING AND DYNAMIC PROBABILISTIC RISK ASSESSMENT

Mandelli, Diego 25 July 2011 (has links)
No description available.
76

Effects of Low-Input Vegetation Management on Pine-Hardwood Mixed Stands in the Northern Piedmont

Heinze, Jason A. 26 June 2000 (has links)
In an attempt to provide low-cost, low-input alternatives for regenerating pine-hardwood mixtures, this study examined several mechanisms that influence the growth of pine-hardwood stands. The Regeneration Alternatives Study is an ongoing experiment that was designed to gain biological and economical information concerning the growth and yield of loblolly pine and mixed hardwood species. Low-cost herbicide applications (stump treatment, basal stem spray, release, and soil spot release) were used to control competing vegetation during the study. The four even-aged regeneration treatments applied to loblolly pine and mixed hardwood stands of this study had a significant effect on their growth. Loblolly pine growth increased and mixed hardwood growth decreased as the intensity of herbicide treatment increased for all age classes. In general, loblolly pine was more productive with more intense treatment applications on poorer sites following a growing season harvest. Hardwood species were more productive with less intense treatment applications on higher-quality sites following a dormant season harvest for all age classes. Loblolly pine planting following clearfelling, coupled with a herbicide stump and release treatment (treatment 4), resulted in the highest yields of loblolly pine, the greatest economic returns, and the greatest level of site utilization. However, treatment 4 also resulted in the lowest yield of mixed hardwoods and the lowest level of species richness. Loblolly pine planting following clearfelling, with (treatment 3) and without (treatment 2) a hardwood stump treatment application, resulted in a more even distribution of pines and hardwoods, depending on the treatment. Treatment 3 favored loblolly pine growth, especially following a growing season harvest on poor sites. Treatment 2 favored mixed hardwood growth, especially following a dormant season harvest on good sites. There were no differences between methods of release (basal spray or soil spot herbicide application). Economically, treatments 2 and 3 did not realize a profit on returns. Pine yields, dbh, and basal area were all significantly greater following a summer season harvest as opposed to pine growth following a winter harvest with the same chemical treatments. The pine growth data indicated that less intense chemical treatments following a summer harvest can achieve the same or greater growth results than more intense chemical treatments following a winter harvest. The results of this study indicate a significant biological and economic tradeoff, depending on the level of hardwood control applied and the time of harvesting. / Master of Science
77

Economic Comparisons Between an Even-Aged and an Uneven-Aged Loblolly Pine Silvicultural System

Cafferata, Michael J.S. 28 May 1997 (has links)
This study compares financially optimal uneven-aged and even-aged silvicultural regimes of loblolly pine (Pinus Taeda). Uneven-aged regimes which maximize net present value (NPV) are found by quantifying the effects of diameter distribution (Q factor), maximum diameter, cutting cycle, and residual basal area on NPV. For the benchmark inputs, the regime yielding the highest NPV had a maximum diameter of 12 inches, residual basal area of 45 ft²/acre, and a cutting cycle of 11 years. Financially optimal even-aged regimes are taken from published literature of even-aged silviculture. Even-aged and uneven-aged silvicultural regimes are simulated starting from, 1) bare land, 2) a balanced uneven-aged loblolly pine stand, and 3) a mature even-aged loblolly pine stand. For the three starting conditions and selected benchmark variable values, simulation of even-aged silviculture yields NPVs of $877, $2,152 and $3,400 per acre and simulation of uneven-aged silviculture yields NPVs of $644, $2,084, and $2,569 per acre. Sensitivity analysis shows, for the levels of the variables tested, that even-aged silviculture yields higher NPVs than uneven-aged silviculture when starting from bare land or from a mature even-aged stand. When starting from an uneven-aged stand, for the variable values tested, uneven and even-aged silviculture are financially very competitive. Aside from the aesthetic benefits of avoiding clearcutting under uneven-aged silviculture, non-timber considerations between loblolly pine silvicultural systems are not well documented. Resource professionals hold opinions often in direct conflict with each other regarding the non-timber costs and benefits of even-aged and uneven-aged silviculture when considering wildlife, soil and water, and catastrophic damage events. / Master of Science
78

A compact filtering antenna with step and continuous tuning modes for WiMAX cognitive radio communication

Alnahwi, F.M., Abdulhameed, A.A., Ali, N.T., Al-Yasir, Yasir I.A., Kubik, Z., Abdullah, A.S., Abd-Alhameed, Raed 19 December 2023 (has links)
Yes / This work presents a combination of a cup-shaped monopole antenna and an E-shaped Multi-Mode Resonator (MMR) with the presence of a pair of PIN diodes and a varactor diode to form a compact reconfigurable communication filtering antenna for interweave Cognitive Radio (CR) systems. The proposed filtering antenna operates in the WiMAX band, and it is fabricated on an FR4 substrate with overall dimensions normalized to the wavelength ( λ o ) of the first resonant frequency (0.413λ o × 0.516λ o × 0.0165λ o ). The step and continuous tuning serve the secondary user of the WiMAX CR system to communicate in the absence of the primary users at modifiable resonant frequencies and data rates.When the PIN diodes are OFF, the filtering antenna operates with a fixed odd mode resonant frequency and tunable even mode resonant frequency. This state results in a tunable antenna bandwidth covering a maximum measured frequency range of 3.25-4.02~ GHz and a minimum measured range equal to 3.25-3.58~ GHz. The ON state of the PIN diodes eliminates the antenna matching at the even mode resonant frequency while keeping a strong matching at the odd mode resonant frequency. The resulted operational measured frequency range of the antenna in this state is fixed at 2.9-3.28~ GHz. The filtering antenna has acceptable gain values at the pass band of the E-shaped MMR with a maximum simulated gain value equal to 2.5~ dB and a measured maximum gain equal to 2.48~ dB. The simulated and measured power patterns of the antenna for all diodes states are omnidirectional, which are convenient for portable CR gadgets. / This work was supported in part by the Innovation Programme under Grant H2020-MSCA-ITN-2016 SECRET-722424, and in part by the U.K. Engineering and Physical Sciences Research Council (EPSRC) under Grant EP/E022936/1.
79

Resonances: Marcel Duchamp and the Comte de Lautréamont

Cushing, Douglas Clifton 12 September 2014 (has links)
This thesis explores the relationship between Marcel Duchamp’s oeuvre and the texts of the Comte de Lautréamont, arguing that the author’s works comprise an overlooked and undervalued source of interest and ideas for the artist. Scholars have done an extraordinary job of documenting and analyzing a number of Duchamp’s literary sources and inspirations. Their work has elucidated the roles of Raymond Roussel, Alfred Jarry, Stéphane Mallarmé, Jules Laforgue, and Jean-Pierre Brisset, among others, for Duchamp. The work of Lautréamont, however, has received proportionally little attention, despite several indications of its importance for the artist. Among the few who have proposed such a connection, none have yet offered a broadly documented or sustained argument. Other historians, generally working under the premise that Lautréamont only came to Duchamp’s attention by way of the Surrealists, have explicitly rejected the possibility that the Uruguayan-French poet had any meaningful position in Duchamp’s library prior to the Surrealist championing of the author. This thesis proposes otherwise, making the case that Lautréamont was more fundamentally important to Duchamp than yet realized. Historical documents as well as statements by the artist himself and those closest to him suggest a stronger engagement by Duchamp with the works of Lautréamont than has been previously proposed. This relationship seems to have begun by as early as 1912, well in advance of the Surrealists’ discovery of the author, and it lasted throughout Duchamp’s life. Furthermore, an examination of Duchamp’s body of work demonstrates a number of strategic and thematic resonances between artist and author that reinforce what the archival evidence suggests. These resonances should be understood as open readings, rather than exclusive readings. They are proposed as additions to the existing constellation of understanding of Duchamp’s oeuvre, rather than as foreclosures upon other ways of reading Duchamp’s body of work. / text
80

Loops de código: automorfismos e representações / Code loops: automorphisms and representations

Pires, Rosemary Miguel 16 May 2011 (has links)
Neste trabalho, estudamos Loops de Código. Para este estudo, introduzimos os loops de código a partir de códigos pares e depois, provamos que loops de código de posto $n$ podem ser caracterizados como imagem homomórfica de certos loops de Moufang livres com n geradores. Além disso, introduzimos o conceito de vetores característicos associados a um loop de código. Com os resultados da teoria estudada, classificamos todos os loops de código de posto 3 e 4, encontramos todos os grupos de automorfismos externos destes loops e, finalmente, determinamos todas as suas respectivas representações básicas. / This work is about code loops. For this study, we introduce the code loops from even codes and then we prove that code loops of rank n can be characterized as a homomorphic image of a certain free Moufang loops with $n$ generators. Moreover, we introduce the concept of characteristic vectors associated with code loops. With the results of this theory, we classify all the code loops of rank 3 and 4, we find all the groups of outer automorphisms of these loops and finally we determine all their basic representations.

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