The purpose of this study is: 1) to explore the ways in which the Internet may affect individuals’ political diversity in different strengths of social relationships; 2) to identify which of strong-tie diversity and weak-tie diversity contributes more to political tolerance; and 3) to investigate the extent to which tolerant people are different from the less tolerant in their participation decisions when exposed to political diversity. In order to examine the contribution of Internet news use to political heterogeneity, the current study examines the moderation of the negative influence of politically selective exposure on the Internet on political diversity in social networks by Internet news use. To identify the better contributor to tolerance, the two diversities are compared. To assess the consequence of exposure to political difference for political participation for tolerant and less tolerant people, the present study examines any moderating effect of tolerance between political network heterogeneity and participation. It also observes the moderating effect in different tie strengths. This study utilizes data obtained from the U.S. Citizenship, Involvement, Democracy (CID) survey conducted by a collaboration of Center for Democracy and Civil Society at Georgetown University and the European Social Survey. The sample is 1,001 adults aged 18 and over and representative of the contiguous United States. The dataset contains items concerning Internet use, informal social networks, the composition and diversity of ties and associations, democratic values and tolerance under the primary themes of democracy, social capital and civic engagement. The data are analyzed by hierarchical and OLS regression. According to the findings, Internet news use contributes to individuals’ overall political diversity by reducing the negative influence of the selective exposure occurring from online interaction with homogeneous people. When examined in different strengths of interpersonal relationships, selective exposure discourages strong-tie diversity while encouraging weak-tie diversity. Internet news use positively affects strong-tie diversity but had no influence on weak-tie diversity. Weak-tie diversity is found to be a better contributor to political tolerance. Politically tolerant individuals tend to be discouraged for political participation when exposed to difference in their social relationships. Therefore, while political tolerance may increase overall political diversity, it may as well threaten the balance between deliberation and participation. Closer interpersonal associations are not found to reduce the demobilizing effect of exposure to difference for tolerant individuals. / text

Club Texas: Building Community in Electronic Music Fan Culture through Online Collaboration is a report of results from a content analysis that analyzes the role of online participatory culture for community development and social capital for a local underground EDM ‘scene’ (Electronic Dance Music) in Dallas, TX. This study analyzes DallasDanceMusic.com (DDM), one of the first and largest message board communities to support the EDM community in Dallas, TX since 1994. The study measures participatory culture and social capital using content analysis of the site during high profile activity for a four-month period in 2012. / text

Protein-protein interactions are of great importance to a number of essential biological processes including cell cycle regulation, cell-cell interactions, DNA replication, transcription and translation. Thus, an understanding of protein-protein interactions is critical for understanding many facets of cell function. Unfortunately, the tools and methods currently in use to identify and study protein-protein interactions focus largely on high affinity, stable interactions. However, the majority of the protein-protein interactions involved in regulatory processes have weak affinities and are transient in nature. Therefore, it is important to develop new biotechnology capable of detecting weak and/or transient protein-protein interactions in vivo. Here, we describe four new methods that allow for the identification and study of weak and/or transient protein-protein interactions in vivo. First, we developed a rapid method to convert Escherichia coli orthogonal tRNA/synthetase pairs into an orthogonal system for mammalian cells in order to site-specifically incorporate unnatural amino acids into any gene of interest using stop codon suppression. This method will allow the expression and purification of proteins that carry normally transient post-translational modifications. Second, we successfully employed site-specific unnatural amino acid incorporation to chemically cross-link a known homodimer, Sortase A, in vivo. Third, we developed a novel tetracycline repressor-based mammalian two-hybrid system and successfully detected homo- and hetero-dimers that are known to have weak binding constants. Finally, a synthetic antibody (termed a synbody) that binds weakly to the SH3 domain of the proto-oncogene Abelson tyrosine kinase was developed. The synbody can potentially be used as a first generation drug and/or biomarker. We hope that the methods developed in this dissertation will enable the scientific community to better understand weak/transient protein-protein interactions in vivo. / text

We consider three problems in this dissertation, all under the unifying theme of random matrix products. The first and second problems are concerned with weak convergence in stochastic matrices and circulant matrices, respectively, and the third is concerned with the numerical calculation of the Lyapunov exponent associated with some random Fibonacci sequences. Stochastic matrices are nonnegative matrices whose row sums are all equal to 1. They are most commonly encountered as transition matrices of Markov chains. Circulant matrices, on the other hand, are matrices where each row after the first is just the previous row cyclically shifted to the right by one position. Like stochastic matrices, circulant matrices are ubiquitous in the literature.In the first problem, we study the weak convergence of the convolution sequence mu to the n, where mu is a probability measure with support S sub mu inside the space S of d by d stochastic matrices, d greater than or equal to 3. Note that mu to the n is precisely the distribution of the product X sub 1 times X sub 2 times and so on times X sub n of the mu distributed independent random variables X sub 1, X sub 2, and so on, X sub n taking values in S. In [CR] Santanu Chakraborty and B.V. Rao introduced a cyclicity condition on S sub mu and showed that this condition is necessary and sufficient for mu to the n to not converge weakly when d is equal to 3 and the minimal rank r of the matrices in the closed semigroup S generated by S sub mu is 2. Here, we extend this result to any d bigger than 3. Moreover, we show that when the minimal rank r is not 2, this result does not always hold.The second problem is an investigation of weak convergence in another direction, namely the case when the probability measure mu's support S sub mu consists of d by d circulant matrices, d greater than or equal to 3, which are not necessarily nonnegative. The resulting semigroup S generated by S sub mu now lacking the nice property of compactness in the case of stochastic matrices, we assume tightness of the sequence mu to the n to analyze the problem. Our approach is based on the work of Mukherjea and his collaborators, who in [LM] and [DM] presented a method based on a bookkeeping of the possible structure of the compact kernel K of S.The third problem considered in this dissertation is the numerical determination of Lyapunov exponents of some random Fibonacci sequences, which are stochastic versions of the classical Fibonacci sequence f sub (n plus 1) equals f sub n plus f sub (n minus 1), n greater than or equal to 1, and f sub 0 equal f sub 1 equals 1, obtained by randomizing one or both signs on the right side of the defining equation and or adding a "growth parameter." These sequences may be viewed as coming from a sequence of products of i.i.d. random matrices and their rate of growth measured by the associated Lyapunov exponent. Following techniques presented by Embree and Trefethen in their numerical paper [ET], we study the behavior of the Lyapunov exponents as a function of the probability p of choosing plus in the sign randomization.

Mutually unbiased bases is an important topic in the recent quantum system researches. Although there is much work in this area, many problems related to mutually unbiased bases are still open. For example, constructing a complete set of mutually unbiased bases in the Hilbert spaces with composite dimensions has not been achieved yet. This thesis defines a weaker concept than mutually unbiased bases in the Hilbert spaces with composite dimensions. We call this concept, weak mutually unbiased bases. There is a duality between such bases and the geometry of the phase space Zd × Zd, where d is the phase space dimension. To show this duality we study the properties of lines through the origin in Zd × Zd, then we explain the correspondence between the properties of these lines and the properties of the weak mutually unbiased bases. We give an explicit construction of a complete set of weak mutually unbiased bases in the Hilbert space Hd, where d is odd and d = p1p2; p1, p2 are prime numbers. We apply the concept of weak mutually unbiased bases in the context of quantum tomography and quantum cryptography.

This study aims at providing results for the analysis of the stratigraphy underlying contaminated sediments in Ångermanälven. The contaminated sediments, containing heavy metals and persistent organic pollutants, are derived from wastewater discharged into Ångermanälven from nearby paper and pulp industries. These sediments consist of cellulose fibres deposited as fibrebanks, or as fibre-rich sediments in the case where fibres are mixed with natural sediments. The importance of the underlying geology is enhanced since the contaminated sediments are deposited in an area where submarine landslides and slope movements occur frequently. In this study two sediment cores from a fibrebank in Ångermanälven are analysed. This is done in order to assess the risk of contaminants being dispersed in the ecosystem as a result of mass movements. Stratigraphic correlation with results from previous sediment core analysis in the middle of the estuary (International Ocean Discovery Program expedition #347) is achieved through magnetic susceptibility and density measurements of the sediment. Results show that silt layers and clay units situated throughout the estuary are potentially weak and geotechnical investigations are necessary to assess the risk of slope movements over these units. With further analysis of fibrebanks and the use of a vibro-corer, the contact between the fibrebanks and underlying sediment could be captured and further correlation establishing the stratigraphy of the estuary achieved. / Denna studie syftar till att tillhandahålla resultat och tolkningar för analys av den underliggande stratigrafin i Ångermanälven, som överlagrats av förorenade antropogena sediment. De förorenade sedimenten, vilka innehåller tungmetaller samt organiska föroreningar, härrör från avfallsvatten som släppts ut i älven från pappers- och massaindustrin. Sedimenten består av cellulosafibrer och har deponerats som fiberbankar eller fiberrika sediment, varav det sistnämnda består av cellulosa uppblandat med naturliga sediment. Eftersom fiberbankarna och de fiberrika sedimenten är avsatta i ett område där jordskred är vanligt förekommande, är den underliggande geologin som de miljöfarliga sedimenten är avsatta på av avsevärd betydelse. I studien ingår analys av två sedimentborrkärnor från en fiberbank i Ångermanälven. Syftet är att ta fram underlag för att möjliggöra riskbedömning kring spridning av föroreningarna som följd av potentiella jordskred, där de förorenade sedimenten är inblandade. Stratigrafisk korrelation med resultat från tidigare studier i den djupare delen av älven (International Ocean Discovery Program expedition #347) har uppnåtts genom jämförelse av två sedimentegenskaper: sedimentens respons av magnetisk susceptibilitet och densitet. Resultaten visar att silt- och lerlager som återfinns genom hela älven är potentiellt svaga. Vidare är geotekniska undersökningar nödvändiga för att bedöma risken för skred över dessa lager. Analys av fler fiberbankar och användning av ”vibro-corer” istället för kolvbaserad borrmetod, skulle möjliggöra analys av kontakten mellan fiberavsättningarna och den underliggande geologin, samt ytterligare tydliggöra stratigrafin i Ångermanälven.

In recent years, increasing attention has turned toward the effect of health information or health knowledge on nutrient intake. In determining the effect of health information on nutrient demand, researchers face the estimation problem of dealing with the endogeneity of health information knowledge. The standard approach for dealing with this problem is an instrumental variables (IV) procedure. Unfortunately, recent research has demonstrated that the IV procedure may not be reliable in the types of data sets that contain health information and nutrient intakes because the instruments are not sufficiently correlated with the endogenous variables (i.e., instruments are weak). This thesis compares the reliability of the IV procedure (and the Hausman test) with a relatively new procedure, directed graphs, given weak instruments. The goal is to determine if the method of directed graphs performs better in identifying an endogenous variable and also relevant instruments. The performance of the Hausman test and directed graphs are first assessed through conducting a Monte-Carlo sampling experiment containing weak instruments. Because the structure of the model is known in the Monte-Carlo experiment, these results are used as a guideline to determine which procedure would be more reliable in a real world setting. The procedures are then applied to a real-world cross-sectional dataset on nutrient intake. This thesis provides empirical evidence that neither the IV estimator (and Hausman test) or the directed graphs are reliable when instruments are weak, as in a cross-sectional dataset.

Denna uppsats syftar till att testa The Weak Government Hypothesis. Hypotesen är att en fragmenterad regering ackumulerar större skulder än ickefragmenterade regeringar och att graden av fragmentering påverkar storleken på skulden. Hypotesen testas med paneldata över 283 svenska kommuner under perioden 1996-2004. Resultaten från den empiriska studien ger inte något enhälligt stöd åt hypotesen. Studien finner dock visst stöd för att en lokal koalitionsregering bestående av flera jämnstora partier tenderar att ha en positiv effekt på de långfristiga skuldnivåerna under valår. Lokala koalitionsregeringar med partier från olika ideologiska block, så kallade regnbågskoalitioner, tenderar också att ha en generell positiv effekt på de långfristiga skulderna. Resultaten är dock ingalunda robusta. En studie över en längre tidsperiod är önskvärd för att några konkreta slutsatser kring validiteten i hypotesen ska kunna dras.

Darbe gaunama, jog silpno matų konvergavimo erdvės X prasme išlpaukia charakteringųjų transformacijų konvergavimas ir atvirkščiai, jeigu charakteringosios transformacijos konverguoja į funkcijas tolydžias nuliniame taške, tai iš čia išplaukia matų silpnas konvergavimas erdvės X prasme. / It is obtained, that the weak convergence in the sense of X implies the convergence of characteristic transforms, and, on the contrary, if the characteristic transforms converge weakly to the functions contiuous at zero, the from this the weak convergence in the sense of X for the probability measures fallows.

Darbe įrodyta diskreti ribinė teorema bendrųjų Dirichlė eilučių poklasiui meromorfinių funkcijų erdvėje. Pateiktas ribinio mato išreikštinis pavidalas. / The discrete limit theorem for general Dirichlet series in the space of meromorphic functions was proved in this paper. Expressed shape of limit measue was provided.