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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.
121

Estimating Bus Passengers' Origin-Destination of Travel Route Using Data Analytics on Wi-Fi and Bluetooth Signals

Jalali, Shahrzad 16 May 2019 (has links)
Accurate estimation of Origin and Destination (O-D) of passengers has been an essential objective for public transit agencies because knowledge of passengers’ flow enables them to forecast ridership, and plan for bus schedules, and bus routes. However, obtaining O-D information using traditional ways, such as conducting surveys, cannot fulfill today’s requirements of intelligent transportation and route planning in smart cities. Estimating bus passengers’ O-D using Wi-Fi and Bluetooth signals detected from their mobile devices is the primary objective of this project. For this purpose, we collected anonymized passengers’ data using SMATS TrafficBoxTM sensor provided by “SMATS Traffic Solutions” company. We then performed pre-processing steps including data cleaning, feature extraction, and data normalization, then, built various models using data mining techniques. The main challenge in this project was to distinguish between passengers’ and non-passengers’ signals since the sensor captures all signals in its surrounding environment including substantial noise from devices outside of the bus. To address this challenge, we applied Hierarchical and K-Means clustering algorithms to separate passengers from non-passengers’ signals automatically. By assigning GPS data to passengers’ signals, we could find commuters’ O-D. Moreover, we developed a second method based on an online analysis of sequential data, where specific thresholds were set to recognize passengers’ signals in real time. This method could create the O-D matrix online. Finally, in the validation phase, we compared the ground truth data with both estimated O-D matrices in both approaches and calculated their accuracy. Based on the final results, our proposed approaches can detect more than 20% of passengers (compared to 5% detection rate of traditional survey-based methods), and estimate the origin and destination of passengers with an accuracy of about 93%. With such promising results, these approaches are suitable alternatives for traditional and time-consuming ways of obtaining O-D data. This enables public transit companies to enhance their service offering by efficiently planning and scheduling the bus routes, improving ride comfort, and lowering operating costs of urban transportation.
122

Alterações locais induzidas pela secreção tóxicas de Philodryas patagoniensis (Girard, 1857) (Serpentes: Colubridae) / Local alterations induced by the toxic secretion of Philodryas patagoniensis (Serpentes: Colubridae)

Lopes, Priscila Hess 17 June 2008 (has links)
O veneno de Philodryas patagoniensis ocasiona lesões locais importantes e similares as que ocorrem nos acidentes botrópicos. Os mecanismos envolvidos nas ações locais deste veneno são pouco conhecidos. Este estudo tem como objetivo investigar as ações locais morfológicas e inflamatórias do veneno de Philodryas patagoniensis e os mecanismos envolvidos no desenvolvimento da dor e edema, por meio de modulação farmacológica. O teor protéico total do veneno foi de 70-75% de proteínas. A análise eletroforética (SDS-PAGE 7,5-17,5%) apresentou bandas protéicas com pesos moleculares entre 62 e 14 kDa, sendo quatro majoritárias em 62, 48, 35 e 30 kDa. O edema mensurado por pletismografia foi máximo 30 min após a inoculação (53,33 ± 1,43 %), regredindo a partir da 6º hora, mostrou-se dose-dependente sendo a dose mínima edematogênica de 0,82µg e inibido em 45% por EDTA. A atividade nociceptiva foi avaliada pelo tempo (em segundos) em que os animais lambiam ou mordiam a pata injetada, e os resultados mostraram que tal atividade é dose-dependente, sendo significativamente diferente do controle e independente de metaloproteinases, uma vez que não foi inibida pelo EDTA. Através da modulação farmacológica foi possível observar que a dor causada pelo veneno foi inibida pela Indometacina, Cyproheptadina e Tramal, indicando que a mediação é por opióides, prostaglandinas e serotonina. A ação foi potencializada pelo Captopril, sugerindo a possível participação de cininas, bem como pelo L-NAME (10mg/kg). Dexametasona, Prometazina, Arcoxia, Celebra e L-NAME (50mg/kg) não interferiram nesta atividade. O edema foi inibido pela Dexametasona e Indometacina e, portanto, mediado por prostaglandinas e leucotrienos. Captopril, Tramal, Prometazina, L-NAME, Arcoxia e Celebra não foram capazes de interferir significativamente no edema. A injeção intramuscular de 30µg do veneno produziu efeitos de desorganização das fibrilas musculares, hemorragia interfibrilar, edema, infiltrado inflamatório e mionecrose dos tipos coagulativa e miolítica, as quais foram inibidas na presença de PMSF e 1-10Phenantrolina. Três, seis e 24 horas após a inoculação intra-muscular de 60µg de veneno, ocorreu um decréscimo gradativo de proteínas não-colágenas com leve redução em alguns componentes miofibrilares observados por SDS-PAGE. O infiltrado inflamatório induzido em cavidade peritoneal foi máximo três horas após a injeção e a contagem celular diferencial apresentou predominantemente leucócitos polimorfonucleares. A técnica de microscopia intravital direta demonstrou que a administração tópica de 0,1µg de veneno induziu distúrbios marcantes em vênulas pós-capilares, caracterizados por vasodilatação, lesões hemorrágicas distribuídas em focos (microsangramentos) e alterações nas interações leucócito-endotélio, tais como redução do número de leucócitos em rolling, aumento da adesão e indução da migração de células através da parede do endotélio. A inoculação subcutânea do veneno na bolsa escrotal de camundongos induziu efeitos típicos de inflamação aguda, com leucócitos migrados vistos a partir de uma hora após a inoculação, regredindo em 48 horas. O veneno age sobre mastócitos in vitro, causando degranulação e conseqüente liberação de histamina concentração dependente. Os resultados obtidos indicam o potencial inflamatório deste veneno e a cinética dos eventos sugere uma complexa sinergia de diversos efeitos, contribuindo para a severidade do quadro local nos envenenamentos. / The venom of Philodryas patagoniensis causes important and similar local lesions the ones that happen in the botropic accidents. The mechanisms involved in the local actions of this venom are little known. This study has as objective investigates the morphologic and inflammatory local actions of the venom of Philodryas patagoniensis and the mechanisms involved in the development of the pain and edema, through pharmacological modulation. The protein content of the venom was of 70-75%. The eletrophoretic analysis (SDS-PAGE 7,5-17,5%) it presented bands of protein with molecular weights between 62 and 14 kDa, being four majority in 62, 48, 35 and 30 kDa. The edema measured by pletismography, it was maximum 30 min after the inoculation (53,33 ± 1,43%), regressing starting from at 6th hour, it was shown dose-dependent, the edematogenic minimum dose was of 0,82µg and it was inhibited in 45% by EDTA. The nociceptive activity was evaluated by the time (in seconds) in that the animals licked or they bit the injected paw, and the results showed that such activity is dose-dependent, being significantly different from the control and independent of metaloproteinases, once it was not inhibited by EDTA. Through the pharmacological modulation it was possible to observe that the pain caused by the venom was inhibited by Indometacin, Cyproheptadine and Tramal, being mediated by opioids, prostaglandins and serotonin. It was potentiated by Captopril, suggesting the possible participation of kinins, as well as for L-NAME (10mg/kg). Dexamethasone, Prometazine, Arcoxia, Celebra and L-NAME (50mg/kg) didn\'t interfere in this activity. The edema was inhibited by Dexamethasone and Indometacin and, therefore, mediated for prostaglandins and leukotrienos. Captopril, Tramal, Prometazine, L-NAME, Arcoxia and Celebra were not capable to interfere significantly in the edema. The intramuscular injection of 30µg of the venom produced effects as disorganization of the muscular fibrils, hemorrhage, edema, inflammatory infiltrated and mionecrosis of the coagulative and miolitic types, which were inhibited in the presence of PMSF and 1-10Phenantrolina. Three, six and 24 hours after the intra-muscular inoculation of 60µg of venom, happened a gradual decrease of proteins no-colagen with light reduction in some miofibrilar components observed by SDS-PAGE (17,5%). The inflammatory infiltrated induced in cavity peritoneal was maximum three hours after the injection and the differential cellular counting presented polimorfonuclear leukocytes predominantly. The technique of intravital microscopy direct demonstrated that the topical administration of venom 0,1µg induced outstanding disturbances in post-capillary venules, characterized by vasodilatation, hemorrhagic lesions distributed in focuses (microbleedings) and alterations in the interactions leukocyte-endothelium, such as reduction of the number of leukocytes in rolling, increase of the adhesion and induction of the migration of cells through the wall of the endothelium. The subcutaneous inoculation of the venom in the scrotal bag of mice induced typical effects of sharp inflammation, with migrated leukocytes seen starting from one hour after the inoculation, regressing in 48 hours. The venom acts on mast cells in vitro, causing degranulating and consequent liberation of histamine concentration-dependent. The results obtained indicate the inflammatory potential of this venom and the kinetics of the events suggests a complex synergy of several effects, contributing to the severity of the local picture in the envenomings.
123

A Bayesian Approach to the Understanding of Exoplanet Populations and the Origin of Life

Chen, Jingjing January 2018 (has links)
The study of extrasolar planets, or exoplanets for short, has developed rapidly over the last decade. While we have spent much effort building both ground-based and space telescopes to search for exoplanets, it is even more important that we use the observational data wisely to understand them. Exoplanets are of great interest to both astronomers and the general public because they have shown varieties of characteristics that we couldn't have anticipated from planets within our Solar System. To properly analyze the exoplanet populations, we need the tools of statistics. Therefore, in Chapter 1, I describe the science background as well as the statistical methods which will be applied in this thesis. In Chapter 2, I discuss how to train a hierarchical Bayesian model in detail to fit the relationship between masses and radii of exoplanets and categorize exoplanets based on that. A natural application that comes with the model is to use it for future observations of mass/radius and predict the other measurement. Thus I will show two application cases in Chapter 3. Composition of an exoplanet is also very much constrained by its mass and radius. I will show an easy way to constrain the composition of exoplanets in Chapter 4 and discuss how more complicated methods can be applied in future works. Of even greater interest is whether there is life elsewhere in the Universe. Although the future discovery of extraterrestrial life might be totally a fluke, a clear sketched plan always gives us some directions. Research in this area is still very preliminary. Fortunately, besides directly searching for extraterrestrial life, we can also apply statistical reasoning to first estimate the rate of abiogenesis, which will give us some clue on the question of whether there is extraterrestrial life in a probabilistic way. In Chapter 5, I will discuss how different methods can constrain the abiogenesis rate in an informatics perspective. Finally I will give a brief summary in Chapter 6.
124

Multi-scale metabolism: from the origin of life to microbial ecology

Goldford, Joshua Elliot 11 December 2018 (has links)
Metabolism is a key attribute of life on Earth at multiple spatial and temporal scales, involved in processes ranging from cellular reproduction to biogeochemical cycles. While metabolic network modeling approaches have enabled significant progress at the cellular-scale, extending these techniques to address questions at both the ecosystem and planetary-scales remains highly unexplored. In this thesis, I integrate various multi-scale metabolic network modeling approaches to address key questions with regard to both the long-term evolution of metabolism in the biosphere and the metabolic processes that take place in complex microbial communities. The first portion of my thesis work, focused on the evolution of ancient metabolic networks, attempts to model the emergence of ecosystem-level metabolism from simple geochemical precursors. By integrating network-based algorithms, physiochemical constraints, and geochemical estimates of ancient Earth, I explored whether a complex metabolic network could have emerged without phosphate, a key molecular component in modern-day living systems, known to be poorly available at the onset of life. We found that phosphate may have not been essential in early living systems, and that thioesters may have been the primitive energy currency in ancient metabolic networks. By generalizing this approach to explore the scope of geochemical scenarios that could have given rise to living systems, I found that other key biomolecules, including fixed nitrogen, may have not been required at the earliest stages in biochemical evolution. The second portion of my thesis deals with a different aspect of ecosystem-level metabolism, namely the role of metabolism in shaping the structure of microbial communities. I studied the relationship between metabolism and microbial community assembly using microbial communities grown in synthetic laboratory environments. We found that a generalized statistical consumer-resource model recapitulates the emergent phenomena observed in these experiments. Future work could seek to better clarify the connection between the fundamental rules that led to life’s emergence over 4 billion years ago and the laws that shape microbial ecosystems today. An ecosystems-level metabolic perspective may aid in our understanding of both the emergence and maintenance of the biosphere.
125

Towards constructing functional protocells for origin of life studies

Jin, Lin 03 July 2018 (has links)
Earth’s crust and primordial ocean formed more than 4 billion years ago and life is believed to have originated on earth at least 3.6 billion years ago. This suggests that primitive cellular life must have evolved from non-living matter during that period of several hundred million years. To study the transition from chemistry to biology, a simple vesicular system called a protocell is an ideal model that is self-organized and contains informational or metabolic materials. This thesis starts by exploring the replication of a model genetic material under plausible prebiotic conditions. The non-enzymatic copying of RNA was found to be catalyzed by Fe2+, which used to be abundant in aqueous environments on the early anoxic earth. Fe2+ was found to be a better catalyst of non-enzymatic RNA copying and ligation in slightly acidic to neutral pH conditions than Mg2+, the divalent cation used to catalyze these reactions in previous studies. This finding suggests that ferrous iron could have facilitated the replication and evolution of RNA on the prebiotic earth. To gain a better understanding of the properties of protocell membranes, the impact of membrane composition and multi-bilayer structure on non-enzymatic and enzymatic biochemical reactions was studied. A fatty acid/phospholipid hybrid membrane system was proposed as a potential intermediate state in protocellular evolution. This membrane composition was investigated for its stability and permeability, two fundamental features of functional protocells. The system proved stable in the presence of divalent cations and retained permeability to small building block molecule. Vesicles with this composition were shown to host faster non-enzymatic RNA copying, and to enable enzymatic protein synthesis. To study the effects of multi-lamellarity, giant multilamellar vesicles (GMVs) were prepared by an extrusion-dialysis method. Compared with small unilamellar vesicles (SUVs), GMVs show slightly better ability to retain encapsulated RNA, while maintaining good permeability for small charged molecules. The multilamellar structure also promotes non-enzymatic RNA copying, providing preliminary evidence that membranes could also mediate catalytic functions as well as acting as a compartment. / 2020-07-02T00:00:00Z
126

Spontaneous Cooperative Assembly of Replicative Catalytic RNA Systems

Vaidya, Nilesh 01 January 2012 (has links)
The RNA World hypothesis proposes a period of time during the origins of life in which RNA molecules were the only source of both genotypes and phenotypes. Although a vast amount of evidence has been obtained in support of this hypothesis, a few critical demonstrations are lacking. A most crucial one is a demonstration of self-replication of RNA molecule from prebiotic soup. Previously in the Lehman laboratory, it has been demonstrated that a 198-nucleotide molecule derived from the Azoarcus group I intron can self-assemble from up to four fragments of RNA via recombination. Furthermore, the covalent full-length molecules are catalytically active and can make copies of themselves from the remaining pieces in the solution leading to their autocatalytic growth. I was able to demonstrate how this recombination system can overcome different obstacles and evolve to be an efficient replicating system. I discovered the ability of a single RNA fragment to be multifunctional in a single reaction pathway during RNA recombination events that avoids the necessity of multiple genotypes. I also confirmed the capacity of self-replicating ribozymes to form cooperative catalytic cycles and networks that would potentially prevent informational decay. Finally, I have discovered a recycling phenomenon in the RNA recombination system that exploits dynamic covalent chemistry. Recycling provides the earliest replicating system with adequate concentrations of reagents and ability to explore sequence space. Together these findings have improved our understanding of RNA recombination and bolstered the plausibility of the RNA World.
127

The Role Of Evolution In The Pathogenesis And Virulence Of Mycobacterium Tuberculosis And The Impact On Tuberculosis Control

January 2014 (has links)
Despite the development of a vaccine and several antibiotics, tuberculosis continues to be one of the leading causes in mortality in the world. The pathogenesis of the main causative agent, Mycobacterium tuberculosis, has puzzled many researchers for over a century. Research on the origin of M. tuberculosis can provide new knowledge on how the organism has evolved into the dangerous pathogen it is today. This thesis reviews recent literature on how the evolution of tuberculosis has contributed to the genetic diversity and positive control of select genes in the tuberculosis genome and how this can impact future development of therapeutic agents. / acase@tulane.edu
128

Do consumers value destination of origin labeling? : the case for native plants and seeds in Nevada

Cowee, Margaret W. January 2005 (has links)
Thesis (M.S.)--University of Nevada, Reno, 2005. / "December 2005." Includes bibliographical references (leaves 27-31). Online version available on the World Wide Web.
129

Home Sweet Home

Lejbro, Max, Andersson, Kristoffer January 2009 (has links)
<p>Research Question: What is it that determines if large companies in the same country and industry use their Country of Origin or not when they want to attract new customers abroad?</p><p>Purpose: Our purpose with this Minor Field Study is to find out if companies within the Brazilian textile industry are using their COO and identify which factors that determine why they use it or not. By analyzing these factors, if and why they are important or not, we can develop a model with the purpose to give companies an idea of how close they are from to being able to use their COO. </p><p>Method: We have worked with a qualitative research method where we interviewed two Brazilian companies, CI Hering and Karsten, which is working within the Brazilian textile industry.</p><p>Theoretical framework: Our theories are mainly concerning the subjects of branding, nation brands, COO and competitive identity. We have also studied the so called Nation Brands Index and its hexagon. We will use theories of nation branding and COO to illustrate their importance to a country’s international companies. </p><p>Empirical framework: This part will show the outcome of our interviews with Hering and Karsten but also present some data on the nation brand of Brazil and activities linked to it.</p><p>Conclusion: We have found that there are six factors that mainly determine if a company will use its COO when trying to attract new customers abroad, and how appropriate this will be. The six factors are: Strong identity/image, brand awareness, knowledge, consistent and strong nation brand, research and willingness. Our final conclusions are that international companies that want to manage their reputation can benefit from relating their identity to some of the aspects in the national identity of their country. Associating to your COO is a way of doing this that aligns your company´s image to the image of your home country.</p>
130

Räcker Svenskheten Till? : En studie i svenska företags användning av svenskheten som differentieringsverktyg vid en utlandsetablering

Jägerlind, Susanna, Mårtens, Carolina January 2007 (has links)
<p>Sverige är i ekonomiska sammanhang ett litet land, en begränsad hemmamarknad tvingar företag utomlands för att möjliggöra en expansion. Sverige är internationellt känt som en designnation och uttrycken ”Swedish Grace” samt ”Swedish Modern” har blivit synonymt med kvalitet, säkerhet och nytänkande. Problemet som denna uppsats ämnar att undersöka är i vilken utsträckning svenska design-</p><p>företag anpassar eller standardiserar svenskheten vid en utlandsetablering.</p><p>Syftet med uppsatsen är att med en jämförande studie utvärdera och analysera hur tre stycken små och ett stort svenskt designföretag väljer marknadsföringsstrategi</p><p>vid en utlandsetablering. Vi har ingående studerat dessa fyra företag och datainsamlingen har skett med hjälp av kvalitativa intervjuer med representanter från företagen.</p><p>Vår undersökning har visat att valet att anpassa eller standardisera svenskheten är kunskap- och erfarenhetsstyrt, men även beroende av företagets storlek. Skillnaderna vi sett mellan det stora och de mindre företagen kan följaktligen kopplas samman med ekonomiska förutsättningar samt deras erfarenhet från den nya marknaden.</p>

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