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Orimoto, Mika. "Regional analysis of extreme gust wind speed." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7043.
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There are two objectives of this study. The first objective is to determine the domain of attraction of an extreme value distribution of gust wind speeds, at a selected station, when only limited samples from the site are available. The second objective is to perform a series of homogeneity tests for the selected stations, such that homogenous regions for these extreme gust winds may be identified. After carefully examining the wind data available, it was decided that 133 out of more than 750 stations in the contiguous United States were selected for the study. These selected stations all have confirmed Exposure C environments, with at least 15 years of records. All wind speeds used in this study were adjusted to 10 meters above ground level. On the basis of a S-statistic method, the proper representations of extreme gust winds at the 133 selected weather stations in the contiguous United States are examined. The results indicate that the annual extreme gust wind speeds at 65 out of the 133 stations are Gumbel extreme value distributions (Type I), whereas the other 68 stations' extreme gust wind speeds are reverse Weibull (Type III), distributed. Nine homogeneous regions, for the annual extreme gust winds, were identified by applying a Type I based regional analysis. This analysis was applied to the 65 stations in the contiguous United States whose annual extreme gust winds are Type I distributed.x, 92 leaves
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Bekemeyer, P. "Rapid computational aerodynamics for aircraft gust response analysis." Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3027827/.
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Computational engineering methods play a more and more important role in building aircraft that move people and goods. Particular in high-speed civil air transport increased usage of higher fidelity simulation tools are expected to enable greener designs with a reduced environmental footprint. The challenge of including computational fluid dynamics in aircraft loads and aeroelasticity is addressed herein. During the aircraft design and certification process a tremendous number of dynamic responses to atmospheric turbulence need to be analysed. Current industrial loads computations are based on corrected linear potential flow methods which offer fast predictions but suffer several drawbacks once aerodynamic non-linearities occur. Instead, aerodynamic loads offered by computational fluid dynamics are highly accurate also at these non-linear conditions. However, computational cost necessary for performing time-marching simulations makes these methods prohibitive for unsteady loads in an industrial context. This work addresses how to efficiently introduce computational fluid dynamics based aerodynamics during gust loads analysis. It is shown that using frequency domain methods in conjunction with reduced order modelling techniques based on modal decomposition and projection offer accurate models which can be analysed at low cost. The three requirements of such an industrial gust loads process are, first, the need for high accuracy, secondly, a significant reduction of runtime compared to unsteady full order time-marching simulations, and thirdly, the ability to automatise the generation and solution process of the reduced model as well as the design and certification process. Therefore, the linearised frequency domain method is extended towards gust responses by altering the right-hand side forcing term. An aerodynamic reduced order model is constructed by computing a modal basis using proper orthogonal decomposition and projecting the linearised equations afterwards. Finally, a coupled aeroelastic model is obtained by combining the aerodynamics model with eigenmodes of the coupled Jacobian matrix for the structural vibration and projecting the coupled linearised equations. The final small sized aeroelastic model enables the inclusion of highly accurate loads during time-critical gust loads analysis and provides the opportunity to introduce these loads in a wider multidisciplinary context. Thus it is a substantial step towards establishing computational fluid dynamics for unsteady aeroelastic analysis.
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Knoblach, Andreas [Verfasser]. "Robust Performance Analysis for Gust Loads Computation / Andreas Knoblach." München : Verlag Dr. Hut, 2015. http://d-nb.info/1076437699/34.
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Miftach, Fetri Emirudin Hartawan. "The application of multivariable control methods to gust load alleviation analysis." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311343.
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Lanier, Prather Jonathan. "Stereovision Correction Using Modal Analysis." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31662.
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Presently, aerial photography remains a popular method for surveillance of landscapes, and its uses continually grow as it is used to monitor trends in areas such as plant distribution and urban construction. The use of computer vision, or more specifically stereo vision, is one common method of gathering this information. By mounting a stereo vision system on the wings of an unmanned aircraft it becomes very useful tool. This technique however, becomes less accurate as stereo vision baselines become longer, aircraft wing spans are increased, and aircraft wings become increasingly flexible. Typically, ideal stereo vision systems involve stationary cameras with parallel fields of view. For an operational aircraft with a stereo vision system installed, stationary cameras can not be expected because the aircraft will experience random atmospheric turbulence in the form of gusts that will excite the dominate frequencies of the aircraft.
A method of stereo image rectification has been developed for cases where cameras that will be allowed to deflect on the wings of an fixed wing aircraft that is subjected to random excitation. The process begins by developing a dynamic model the estimates the behavior of a flexible stereo vision system and corrects images collected at maximum deflection. Testing of this method was performed on a flexible stereo vision system subjected to resonance excitation where a reduction in stereo vision distance error is shown. Successful demonstration of this ability is then repeated on a flying wing aircraft by the using a modal survey to understand its behavior. Finally, the flying wing aircraft is subjected to random excitation and a least square fit of the random excitation signal is used to determine points of maximum deflection suitable for stereo image rectification. Using the same techniques for image rectification in resonance excitation, significant reductions in stereo distance errors are shown.Master of Science
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Jingeleski, David John. "Aerodynamic Analysis of Variable Geometry Raked Wingtips for Mid-Range Transonic Transport Aircraft." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/49562.
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Previous applications have shown that a wingtip treatment on a commercial airliner will reduce drag and increase fuel efficiency and the most common types of treatment are blended winglets and raked wingtips. With Boeing currently investigating novel designs for its next generation of airliners, a variable geometry raked wingtip novel control effector (VGRWT/NCE) was studied to determine the aerodynamic performance benefits over an untreated wingtip. The Boeing SUGAR design employing a truss-braced wing was selected as the baseline. Vortex lattice method (VLM) and computational fluid dynamics (CFD) software was implemented to analyze the aerodynamic performance of such a configuration applied to a next-generation, transonic, mid-range transport aircraft. Several models were created to simulate various sweep positions for the VGRWT/NCE tip, as well as a baseline model with an untreated wingtip. The majority of investigation was conducted using the VLM software, with CFD used largely as a validation of the VLM analysis. The VGRWT/NCE tip was shown to increase the lift of the wing while also decreasing the drag. As expected, the unswept VGRWT/NCE tip increases the amount of lift available over the untreated wingtip, which will be very beneficial for take-off and landing. Similarly, the swept VGRWT/NCE tip reduced the drag of the wing during cruise compared to the unmodified tip, which will favorably impact the fuel efficiency of the aircraft. Also, the swept VGRWT/NCE tip showed an increase in moment compared to the unmodified wingtip, implying an increase in stability, as well providing an avenue for roll control and gust alleviation for flexible wings. CFD analysis validated VLM as a useful low fidelity tool that yielded quite accurate results. The main results of this study are tabulated "deltas" in the forces and moments on the VGRWT/NCE tip as a function of sweep angle and aileron deflection compared to the baseline wing. A side study of the effects of the joint between the main wing and the movable tip showed that the drag impact can be kept small by careful design.Master of Science
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Welstead, Jason Crouse Gilbert L. "Stability analysis of a segmented free-wing concept for UAS gust alleviation in adverse environments." Auburn, Ala, 2009. http://hdl.handle.net/10415/1847.
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Gust, Norbert [Verfasser], Elfgard [Akademischer Betreuer] Kühnicke, and Norbert [Akademischer Betreuer] Meyendorf. "Improvement of signal analysis for the ultrasonic microscopy / Norbert Gust. Gutachter: Elfgard Kühnicke ; Norbert Meyendorf. Betreuer: Elfgard Kühnicke." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://d-nb.info/1067189602/34.
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RONCALLO, LUCA. "Evolutionary spectral model for thunderstorm outflows and application to the analysis of the dynamic response of structures." Doctoral thesis, Università degli studi di Genova, 2022. http://hdl.handle.net/11567/1080956.
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Thunderstorms are destructive phenomena at the mesoscale with extension of few kilometres and short duration, potentially dangerous for mid-low structures. The nonstationary nature of the wind field generated by thunderstorm outflows makes most of the theory and models developed for extra-tropical cyclones unsuitable and their small extension make them difficult to be detected by one single anemometer. These circumstances prevent the collection of precious data over which research can be carried out and the development of robust models for rapid engineering calculations shared by the scientific community. Therefore, a unified and reliable analytical model for the assessment of the maximum dynamic response to thunderstorms coherent with the techniques commonly adopted in wind engineering is not yet available. In this framework, the thesis introduces an Evolutionary Power Spectral Density (EPSD) model of the wind velocity related of thunderstorm outflows, consistent with full-scale records, and studies its application to calculate the alongwind dynamic response of structures and its maximum from an operative perspective.
The EPSD model is derived starting from the analysis of 129 full-scale thunderstorm records, assuming the turbulent fluctuations uniformly modulated and the turbulence intensity constant. The reliability of the assumptions are verified on the basis of the data available. Three analytical models for the modulating function of the slowly-varying mean wind velocity are proposed. The models are based on the functions extracted from the records and include parameters of physical meaning for the thunderstorm outflow. Moreover, the possibility of adopting the classical spectral models of synoptic winds to model the stationary part of the turbulence is verified. Successively, the EPSD model is adopted to calculate the dynamic response of a set of linear elastic point-like SDOF systems with variable fundamental frequency and damping ratio, both accounting and neglecting the effects of the transient dynamics. In this framework a closed-form solution of the Evolutionary Frequency Response Function (EFRF) is derived. The mean value of the maximum response is estimated based on an Equivalent Parameter Technique (EPT) from literature, generalizing the Davenport’s gust factor technique. The effects of the Poisson hypothesis are investigated and mitigated introducing an equivalent expected frequency. The results are validated with the ones obtained in the time domain starting from the real thunderstorm
records available. Successively, a sensitivity analysis is carried out to assess the influence on the maximum dynamic response of the parameters that shape the modulating function of the velocity.
A closed-form solution for the equivalent parameters and the gust factor is introduced. The comparison with alternative formulations proposed in the literature demonstrates the improved accuracy of the proposed one. Finally, the formulation is extended to the analysis of slender vertical structures, adopting a vertical profile for the mean wind velocity from the literature and the equivalent wind spectrum technique. Two case studies of vertical slender structures are analysed and a comparison with synoptic wind loading conditions is outlined, showing that the proposed model constitutes a valid and handy tool for the evaluation of the wind loading on structures provided by thunderstorm outflows.
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Wojciak, Johannes D. [Verfasser]. "Quantitative Analysis of Vehicle Aerodynamics during Crosswind Gusts / Johannes Wojciak." München : Verlag Dr. Hut, 2012. http://d-nb.info/1028784619/34.
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Hatziioanou, Diane. "Discovery and analysis of novel bacteriocins from gut bacteria." Thesis, University of East Anglia, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539358.
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Durazzi, Francesco. "Comparison of targeted and shotgun animal gut metagenomics." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/17089/.
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The understanding of the composition and functions of the intestinal environment is particularly useful to evaluate and improve productivity and health of farmed animals, such as chickens. By sequencing the metagenome, that represents the genetic material recovered directly from enviromental samples such as gut sections, scientists attempt to retrieve the abundances of microorganisms that inhabit the gut of animals, in order to access information about the interaction with the host. Our purpose is to compare, with a statistical approach, the reliability of two sequencing techniques, called metataxonomics and metagenomics, that can both provide a solid approach to investigate the populations of bacteria in gut microbiome. Although metagenomics, based on shotgun sequencing of the full metagenome, is usually known as the best suited option to recover abundance profiles of bacteria, recent studies have highlighted remarkable results using amplicon sequencing, that targets and recognizes particular regions of 16S rRNA gene. In our study, we take advantage of a well-structured dataset of 78 samples collected from caeca and crops of 40 chickens, at different days of life(1,14,35) and fed (or not) with a probiotic supplemented to drinking water. The study of abundance profiles retrieved by metagenomics and metataxonomics separately, highlights several differences between the two techniques, in terms of detection of rare genera and connection to biological markers. Shotgun sequencing detects around five times more genera than those commonly detected by both techniques, even if several shotgun sets have low coverage. Furthermore, using silhouette scores to evaluate the space segmentation of abundance profiles in a 2-dimensional PCoA space according to biological metadata, we observe that low-abundance bacteria detected only by shotgun contain important biologic information, hidden to 16S sequencing.
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Wallace, Sarah Kate. "Molecular Gut Analysis of Carabids (Coleoptera: carabidae) using Aphid Primers." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/wallace/WallaceS1204.pdf.
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Carabid beetles are found in a variety of Montana crops, although their impact on the food web is poorly known. To detect aphidophagy using the polymerase chain reaction (PCR), carabids were fed a single aphid and allowed to digest for increasing time intervals. Aphidspecific PCR primers were used to amplify aphid DNA from carabid beetles. For the laboratory-fed beetles, PCR detection of aphidophagy decreased with longer digestion periods. Further, there were differences among genera in the proportion of fed beetles positive for aphid DNA at the tested digestion intervals. Field surveys of 273 individual carabid beetle gut contents, representing seven genera, found all genera surveyed in Montana cropping systems, except Microlestes and Pasymachus, positive for aphid DNA. Genera positive for aphid DNA were Calosoma, Harpalus, Pterostichus, Amara, Agonum, and Bembidion. The detectability of prey DNA in the context of predator size is discussed.
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Tweedy, Phillip. "Analysis of Hybrid Electric Autonomous Tactical Support System." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76877.
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The modern day expeditionary warfighter faces extraordinary challenges in the battle field and being a beast of burden should not be one of them. Currently the dismounted warfighter is impeded with carrying over 100lbs of tactical gear and supplies for multiday missions in remote territory. Expeditionary forces are also facing an energy and logistical crisis getting water, fuel, and batteries to the tip of the spear. Finding ways to enable self-sufficiency and reducing resupply tethers for small unit operations is a high priority for the armed forces. The Hybrid Electric Autonomous Tactical Support System directly and efficiently tackles both problems head on by synergizing efforts to lighten the load and self sustaining base power by combining the capabilities of the Ground Unmanned Support Surrogate (GUSS) and the Experimental Forward Operating Base projects. Hybridization of the drivetrain of the GUSS vehicle will provide the reliable power for onboard autonomous systems and also enable silent operation modes. The hybrid onboard generator can efficiently provide generous amounts of exportable DC and AC power on demand and is an ideally sized backup/primary power system for small unit bases and forward command posts. The vehicle's onboard energy storage and generator system can also be linked with renewable energy sources to demonstrate the tactical smart mini grid concept. This thesis develops the power requirements for an autonomous system, GUSS mission derived hybrid electric drivetrain specifications, and Marine Corps small echelon bases for the development of the multifunction Hybrid Electric Autonomous Tactical Support System.Master of Science
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Norrehed, Sara. "Modulation of Molecular Properties : Host–Guest Interactions for Structural Analysis and Chemical Reactions." Doctoral thesis, Uppsala universitet, Syntetisk organisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-207138.
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This thesis concerns the construction, use and modulation of various host–guest systems, from small bispidines for binding of inorganic ions to bisporphyrin clips for supramolecular systems. Small flexible molecules undergo fast conformational movements when in solution. These conformational movements generate time-averaged population-weighted chemical shifts, coupling constants and NOEs when analysed by NMR spectroscopy. A bisporphyrin clip was designed to be used as a host for restriction of conformational movements of small flexible molecules by ditopic metal-ligand binding. Based on conformational analysis in combination with NMR analysis of molecular flexibility in solution (NAMFIS), the relative stereochemistry of flexible alditol-derived diamines containing three or four consecutive stereocentres could be determined. To further explore the idea of conformational deconvolution via host–guest binding, two flexible molecular tweezers with photoswitchable moieties were developed. Upon photoswitching cis/trans isomerisation facilitates the opening and closing of these bisporphyrin hosts. A guest molecule could then be exposed to a “catch and stretch” or “catch and release” effect. Preliminary studies have shown that photoisomerisation of the constructed systems is possible without photodecomposition and preliminary binding studies have been conducted. Controlled modulation of molecular conformations is of interest especially if the conformational steering activates a unit working as a nucleator in a larger structure or facilitates a reaction. The protonation-triggered modulation of bispidine conformations has been investigated. In addition to previously reported conformations we have observed that upon diprotonation a bispidine derivative can be driven into the unusual boat-boat conformation. Finally, the unexpected formation of persistent organic radicals with a cyclophane motif from the reaction of N,N´-diphenyl-1-5-diazacyclooctane and AgBF4 is described. Interestingly, these diradicals exhibit features such as intramolecular π-stacking without lateral displacement and also intramolecular spin pairing.
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Asante, Felix Ankomah. "Economic analysis of decentralisation in rural Ghana /." Frankfurt am Main [u. a.] : Lang, 2003. http://www.gbv.de/dms/zbw/359429173.pdf.
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Crespo, Piazuelo Daniel. "Genomic analysis of fatty acid composition and gut microbiota in pigs." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666884.
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La carne de cerdo es una de las carnes más consumidas en el mundo, cuyo valor se ve afectado por su calidad y las preferencias del consumidor. La composición de los ácidos grasos (AGs) en músculo y tejido adiposo modifica la calidad de la carne. Del mismo modo, la microbiota intestinal, a través de la producción de metabolitos como los ácidos grasos volátiles, puede también afectar su calidad. Sin embargo, la relación entre el genoma del cerdo y su microbiota intestinal no está bien estudiada. En la presente tesis se han realizado una serie de trabajos con el fin de profundizar en los mecanismos genéticos implicados en la determinación de la composición de los AGs. Además, se ha estudiado la composición de la microbiota a lo largo del intestino y su interacción con el genoma porcino.
Se realizaron estudios de asociación del genoma completo (GWAS) entre 38.424 Single Nucleotide Polymorphisms (SNPs) y 60 caracteres fenotípicos relacionados con la composición de los AGs en músculo y grasa dorsal de 441 cerdos pertenecientes a tres retrocruces de la población experimental IBMAP: BC1_LD (25% Ibérico y 75% Landrace), BC1_PI (25% Ibérico y 75% Pietrain), y BC1_DU (25% Ibérico y 75% Duroc). El GWAS reveló nueve regiones del genoma porcino asociadas con doce caracteres de la grasa dorsal y seis regiones asociadas con seis medidas de la grasa intramuscular. Dentro de estas regiones, se identificaron 50 genes como candidatos funcionales a explicar la variación de estos caracteres. Los genes más relevantes fueron ELOVL3, ELOVL6, ELOVL7, FADS2, FASN y SCD. Además, el polimorfismo ELOVL6:c.‑394G>A fue el más asociado con los porcentajes de C14:0, C16:0, y C16:1(n-7) en grasa dorsal.
Para estudiar otras variantes genéticas aparte de los SNPs, se detectaron 1.928.746 indels con tres programas (Dindel, SAMtools mpileup, y GATK) mediante los datos de secuenciación del genoma completo de siete fundadores (dos machos Ibéricos y cinco hembras Landrace) del material IBMAP. Se genotiparon diez indels localizados en genes relacionados con el metabolismo lipídico en los 441 cerdos de los tres retrocruces, encontrándose a distintas frecuencias alélicas. En la grasa intramuscular, el indel C1QTNF12:c.557_559delCCG presentó una asociación significativa con el porcentaje de ácido eicosadienoico (C20:2(n-6)).
Para describir la composición de la microbiota a lo largo del intestino, se recogió el contenido luminal de cinco regiones (duodeno, yeyuno, íleo, colon proximal y distal) de trece cerdos Ibéricos. Posteriormente, mediante el método de amplificación y secuenciación del gen 16S rRNA, se identificaron 1.669 operational taxonomic units (OTUs) agrupados en 179 géneros, siendo los más abundantes Lactobacillus, Clostridium y Prevotella. Las muestras de colon eran más ricas en especies y se parecían más entre cerdos que las muestras del intestino delgado. Además, las predicciones funcionales del metagenoma a lo largo del intestino mostraron que sus rutas energéticas eran distintas.
Finalmente, se estudió la asociación entre el genoma del cerdo y su microbiota intestinal. Se obtuvo la composición de la microbiota del recto de 285 cerdos Ibérico × Duroc mediante la amplificación y secuenciación del gen del 16S rRNA, identificándose un total de 1.257 OTUs agrupados en 101 géneros y 18 filos, siendo los filos más abundantes Firmicutes y Bacteroidetes. El GWAS reveló 17 regiones del genoma porcino asociadas con la abundancia relativa de los géneros Akkermansia, CF231, Phascolarctobacterium, Prevotella, SMB53 y Streptococcus. Dentro de estas regiones, se identificaron 38 genes como candidatos a modular la composición de la microbiota intestinal por su relación con el sistema inmunitario y el metabolismo de los mucopolisacáridos y los ácidos biliares.Pork is one of the most consumed meats worldwide and it is subjected to consumer’s preferences. Meat quality is affected by fatty acid (FA) composition in muscle and adipose tissues. Gut microbiota composition can also affect meat quality through the production of metabolites such as short-chain fatty acids. However, the relationship between pig genome and gut microbiota is not fully understood. In the current thesis, several studies have been performed to improve our knowledge about the genetic determinism of FA composition. In addition, the composition of the microbiota along the pig gut and its interaction with the host genome has been also analysed. Genome-wide association studies (GWAS) were performed among 38,424 single nucleotide polymorphisms (SNPs) and 60 phenotypic traits related to FA composition in backfat and muscle. This analysis was performed in 441 pigs from three different backcrosses: BC1_LD (25% Iberian and 75% Landrace), BC1_PI (25% Iberian and 75% Pietrain), and BC1_DU (25% Iberian and 75% Duroc) belonging to the IBMAP experimental population. Nine regions of the pig genome were associated with twelve backfat traits, while six regions were associated with six intramuscular fat (IMF) traits. A total of 50 candidate genes were proposed to explain the variation in these traits. The most promising candidate genes were ELOVL3, ELOVL6, ELOVL7, FADS2, FASN and SCD. Furthermore, ELOVL6:c.‑394G>A was the most associated SNP with the percentages of C14:0, C16:0, and C16:1(n-7) in backfat. With the aim of detecting other variants apart from SNPs, we performed an indel detection with the whole genome sequencing data from seven founders (two Iberian boars and five Landrace sows) of the IBMAP pigs. A total of 1,928,746 indels were found in common among the three programs used (Dindel, SAMtools mpileup, and GATK). Ten indels inside genes related with lipid metabolism (ASPH, C1QTNF12, CAPN9, CCR7, CRP, GZMA, JMJD1C, LYST, PEX19 and SAMD4B) were genotyped in pigs belonging to the three IBMAP backcrosses, obtaining different allelic frequencies. The C1QTNF12:c.557_559delCCG indel was associated with the percentage of eicosadienoic acid (C20:2(n-6)) in IMF. To describe the microbiota composition along the pig gut, luminal contents of five gut sections (duodenum, jejunum, ileum, and proximal and distal colon) were collected in thirteen Iberian pigs. A total of 1,669 operational taxonomic units (OTUs) grouped in 179 genera were found using the 16S rRNA gene sequencing method. Lactobacillus, Clostridium and Prevotella were the three most abundant genera. Colon samples were more similar among pigs and richer in species than small intestine samples were. The metagenome predictions showed that the energy pathways were different along gut sections. Finally, to reveal the association between host genome and gut microbiota in pigs, the microbiota composition of the rectum of 285 Iberian × Duroc pigs was obtained using the 16S rRNA gene sequencing method, finding 1,257 OTUs distributed in 101 genera and 18 phyla. Firmicutes and Bacteroidetes were the most abundant phyla. GWAS identified 17 genomic regions of the pig genome associated with the relative abundance of six genera (Akkermansia, CF231, Phascolarctobacterium, Prevotella, SMB53 and Streptococcus). A total of 38 candidate genes, related with the host defence system and the metabolism of mucopolysaccharides and bile acids, were suggested to be modulators of the gut microbiota composition.
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Ölander, Tobias. "Culture independent analysis of microbiota in the gut of pine weevils." Thesis, KTH, Skolan för bioteknologi (BIO), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-149650.
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In Sweden, the pine weevil causes damages for several hundreds of millions kronor annually. The discouraged use of insecticides has resulted in that other methods to prevent pine weevil feeding needs to be found. Antifeedants found in the pine weevil own feces is one such alternative. The source of the most active antifeedants in the feces is probably from bacterial or fungal lignin degrading symbionts in the pine weevil gut. The aim of the project was to analyze the pine weevil gut microbiota with the help of culture independent methods. DNA (including bacterial DNA) was extracted from both midgut and egg cells. The extracted DNA was amplified with PCR. A clone library was created by cloning the amplified DNA into plasmid vectors and transforming the vector constructs with chemically competent cells. The clones were amplified again with either colony PCR or plasmid extraction followed by PCR, and used for RFLP (Restriction Fragment Length Polymorphism) and sequencing. Species found in the midgut sample included Acinetobacter sp., Ramlibacter sp., Chryseobacterium sp., Flavisolibacter sp. and Wolbachia sp. Species found in the egg sample included Wolbachia sp. and Halomonas sp. Wolbachia sp. and Halomonas sp. were found to be the dominant members of the midgut and egg cells respectively.
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Chandra, Manosree. "Molecular analysis of a tsetse gut protein with putative agglutinating activity." Thesis, University of Glasgow, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300658.
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Dodd, Ciara Siobhan. "Development and optimisation of PCR-based techniques in predator gut analysis." Thesis, Cardiff University, 2004. http://orca.cf.ac.uk/55533/.
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Pterostichus melanarius (Illiger) has been established as an important predator of slugs in the laboratory, semi-natural environments and in the field. The current method of choice for studying these predator-prey interactions is using monoclonal antibodies (MAbs) coupled with enzyme linked immunosorbent assay (ELISA). Recently, DNA-based detection methods have been suggested as a viable alternative in this area of research. DNA-based detection methods proved suitable for investigating predation by P. melanarius on economically damaging slug species. Mitochondrial DNA primers were designed for the 12S ribosomal RNA gene that were specific for Deroceras reticulatum, members of the Arion hortensis aggregate and the Arion genus. The detection limit and rate of decay of slug DNA in the beetle gut was determined using the slug-specific primers in laboratory-based feeding trials. Slug remains could be reliably detected within beetle guts for at least 24 hours following ingestion, suggesting that this technique would be suitable for detecting predation in the field. Direct comparison of immunological and DNA-based detection methods revealed that the sensitivity of MAb-ELISA is greater than amplification of prey DNA using the polymerase chain reaction (PCR). The implications of these findings are discussed. DNA-based detection methods were suitable for detecting predation by beetles on slugs in the field. The number of slug-positive beetles identified using MAb-ELISA was greater than when PCR and prey-specific primers were used. These results are discussed in the context of the availability of target and alternative prey in the field. Sequence data was also analysed to reveal the population structure and demographic history of A. hortensis aggregate in the British Isles. A high level of differentiation between populations was revealed. The rate of molecular evolution in these species is rapid with high levels of inter-specific divergence. The 12s rRNA gene proved especially useful in phylogenetic reconstruction and corroborated previous results based on morphology and enzyme electrophoresis that the congener, Arion intermedius belongs to the same subgenus (Kobelita) as the aggregate species.
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Athey, Kacie J. "Exploring Predator-Prey Interactions in Agroecosystems through Molecular Gut-Content Analysis." UKnowledge, 2017. http://uknowledge.uky.edu/entomology_etds/35.
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Generalist predators can contribute to vital ecosystem services by potentially inducing trophic cascades as natural enemies of pests in agroecosystems. As the human population of the world gets larger, we need to produce more food on ever-smaller swaths of available land relying on ecosystem services, in the form of pest control, that may contribute to agricultural sustainability. Teasing apart the exact trophic linkages between predators and prey is a vital first step and essential to uncovering which predators are inducing trophic cascades and should be enhanced through conservation biological control.
Combined with ecological experimentation, the main tool used throughout my research to identify trophic linkages is molecular gut-content analysis. I began by investigating mass sampling techniques and found they do not cause contamination in gut-content analysis and may be a simple method for collecting large numbers of cryptic predators for use in determining trophic linkages. Additionally, my research uncovered trophic interactions between stink bugs and generalist predators at multiple scales. Overall, I successfully designed molecular methods to investigate relationships between agricultural pests and generalist predators. A multi-year field study uncovered low predation on stink bug pests in contrast to previous research suggesting that generalist predators were contributing highly to biological control. This research highlights the need for replicated studies before making broad conservation biological control decisions. Although generalist predators were not consuming stink bugs in large numbers, my field cage study showed evidence of superfluous killing by spiders on adult stink bugs, highlighting the need to combine ecological studies with molecular methods to understand consumptive and non-consumptive effects on prey items. Gut-content analysis showed no evidence of consumption, but the field cage study allowed me to uncover the complicated relationships between spiders and stink bugs. In addition, I showed an invasive species can be detected in new areas through molecular gut-content analysis of predators before other sampling methods.
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Meijer, Albert. "Be My Guest: Nation branding and national representation in the Eurovision Song Contest." Thesis, Uppsala universitet, Teologiska institutionen, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208098.
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Since its inception in 1956, the EurovisionSong Contest has been a stage for national representation and an opportunityfor countries to brand themselves. The 2012 Eurovision Song Contest in Baku,Azerbaijan is a prime example of nation branding, both for the host country aswell as the participating countries. Hosting the event gives a country the opportunity to present a specific nation brand, but there are other opportunities for those countries which only have a three-minute time-frame for their performance in presenting a national image. These performances are themain subject of this thesis, which main question is: How do nation-states use the Eurovision Song Contest as a means of nation branding? To answer this question, I use three sub-questions. First, I focus on the concept of identity: how does musical performance represent national and European identity in the context of the Eurovision Song Contest? Secondly, I study the translation of national identity into an image that should appeal to all of Europe, by creating a specific nation brand: how do nations use nation branding through culture as a tool to build an appealing image within the context of Eurovision? Lastly, I study the performance of these nation brands in specific cases during the 2012 Eurovision Song Contest: how is a nation-branded image performed in the Eurovision Song Contest? The first two chapters of my thesis consist of an analysis of literature on identity and nation branding in combination with national representation in Eurovision. My third and last chapter consists of performance analyses of 2012 participants, focusing on performances from Romania, Russia, Ukraine and Montenegro, which in 2012 were some of the richest performances in terms of symbolism concerningnational representation.
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Baker, Ryan. "IMAGING AND ANALYSIS OF LARVAL ZEBRAFISH GUT MOTILITY, AND AUTOMATED TOOLS FOR 3D MICROSCOPY." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23133.
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Nearly all individual members of the animal kingdom have gastrointestinal tracts which feature unique cellular compositions, geometries, and temporal dynamics. These guts are distinct enough from one another, even across siblings or even across the same individual at different points in space and time, that defining meaningful scientific representations of those features is difficult. Studying these guts is also innately challenging as it requires accessing to the insides of the enclosed 3D volumes.
The work presented here describes tools and methodologies designed to address these difficulties. To investigate gut motility, we constructed a combined light sheet fluorescence and differential interference contrast microscope to obtain videos of larval zebrafish (Danio rerio) gut motility and to obtain 3D information about nearby fluorescently tagged cells. Using advanced computer vision algorithms, we quantified aspects of zebrafish gut motility which have never before been characterized, then used that information to identify the effects of different genetic, chemical, and physiological states of zebrafish gut motility. Finally, we designed and constructed an instrument for automating 3D microscopy for future studies.
This dissertation includes previously published and unpublished co-authored material.
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Szczepanska, Anna. "Functional metagenomic analysis of carbohydrate degrading enzymes from the human gut microbiota." Thesis, University of East Anglia, 2011. https://ueaeprints.uea.ac.uk/47983/.
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The gut microbiota is a complex and diverse microbial community that is adapted to a carbohydrate-rich ecosystem. Plant cell wall components (cellulose, hemicelluloses and pectins), resistant starch and various oligosaccharides reach the colon by escaping digestion in the upper gastrointestinal tract. Fermentation of these dietary carbohydrates by the gut microbiota has well-recognised beneficial effects on host health. The microbial community in the human gut requires specific enzymes to efficiently degrade these carbohydrates. In this project, a culture-independent approach based on functional screening of genomic and metagenomic libraries using Escherichia coli and Lactococcus lactis as heterologous expression hosts, was used to isolate novel genes encoding glycoside hydrolase (GH) enzymes. The study identified several active GH enzymes involved in the breakdown of dietary polysaccharides such as starch, cellulose, xylan and β-glucan, recovered from the E. coli metagenomic library. The bioinformatic analysis of the insert from positive clones showed the presence of ORFs with the similarity to enzymes from GH families 13, 43 and 51 encoded by dominant bacterial genera from the human colon (Bacteroides sp., Roseburia sp., Ruminococcus sp.). A group of clones encoding potentially novel GH enzymes was also identified, emphasising the importance of functional-based study. One highly active clone was detected during screening of the L. lactis metagenomic library and showed fibrolytic activity on cellulose-, lichenanand xylan-containing plates. The insert contained a partial gene with the GH9 catalytic domain and identity to the protein from Coprococcus eutactus ART55/1. Further functional analysis established the fibrolytic activity of selected Coprococcus species. Moreover, several active clones were isolated from the Ruminococcus sp. 80/3 genomic library which encoded protein with the similarity to enzymes from GH families 2, 3 and 5. In this work, the traditional approach of expression in E. coli was complemented by using an alternative host – L. lactis. While this did not improve the screening efficiency in terms of number of recovered clones, differences in gene expression and protein export between E. coli and L. lactis were noted during this study which highlights the benefits of using different heterologous hosts in functional metagenomic approaches.
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Bassignani, Ariane. "Metaproteomics analysis to study functionalities of the gut microbiota in large cohorts." Electronic Thesis or Diss., Sorbonne université, 2019. https://theses.hal.science/tel-02871891.
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La métaprotéomique s’attache à identifier et quantifier les protéines d’échantillons biologiques complexes comme le microbiote intestinal humain. L’analyse de plusieurs centaines d’échantillons revêt un intérêt évident compte tenu de la reconnaissance croissante de cet écosystème en tant que partenaire santé. Cependant, les méthodes et protocoles utilisés jusqu’à ce jour en métaprotéomique ne sont pas adaptés à des études de grande ampleur. Nous avons développé des algorithmes, évalué et comparé plusieurs approches d’identification des peptides et protéines et proposé des critères d’évaluation systématiques, avec un intérêt particulier porté sur la réplicabilité des identifications, afin de développer un pipeline de prétraitement adapté à des études d’envergure. Ce travail apporte un socle méthodologique jusqu’ici manquant dans le domaine de la métaprotéomique du microbiote intestinal humain. Nous avons également comparé des méthodes de normalisation des XIC et développé une méthodologie d’imputation des données manquantes permettant d’affiner les estimations d’abondances obtenues par la méthode de SC. Ce travail de thèse a permis de mettre en évidence des biomarqueurs microbiens potentiellement d’intérêt pour prédire la réponse à un régime amaigrissant ou pour caractériser différents phénotypes de MICI. Nous avons également analysé le métaprotéome de plus de 200 patients dans le cadre de l’ANR ProteoCardis adossée au projet MetaCardis, et s’intéressant au lien possible entre microbiote intestinal et maladies cardiovasculaires. La recherche de protéines d’intérêt parmi ces données devrait permettre de découvrir des candidats biomarqueurs de maladies cardiovasculairesMetaproteomics focuses on identifying and quantifying proteins in complex biological samples such as the human gut microbiota. The analysis of several hundred of samples is of interest given the growing recognition of this ecosystem as a health partner. However, the methods and protocols used so far in metaproteomics are not suitable for large-scale studies. We have therefore developed algorithms, evaluated and compared several identification approaches for peptides and proteins and proposed systematic evaluation criteria, with a particular interest in the replicability of identifications, in order to develop a pre-treatment pipeline suitable for wide-ranging studies. This work bring a methodological base so far missing in the field of the metaproteomics of the human gut microbiota. Quantification of peptides and proteins by XIC has never been performed on this type of data, we have also compared normalization methods and developed a methodology for imputing missing data to refine the abundance estimations obtained by the more classical method of SC. This thesis work has highlighted microbial biomarkers of potential interest for predicting the response to a slimming diet, or to characterize various phenotypes of IBD. We have also been able to analyse the metaproteome of more than 200 patients in the framework of the ProteoCardis ANR, which is ancillary to the European project MetaCardis, and which focuses on the potential link between gut microbiota and cardiovascular diseases. The search for proteins of interest among these data should allow us to discover protective or aggravating candidate biomarkers of cardiovascular diseases
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Meier, Stephan. "An economic analysis of pro-social behavior : decisions to contribute money and time to public goods /." Zürich, 2004. http://aleph.unisg.ch/hsgscan/hm00148514.pdf.
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Trautman, Laurie. "Temporary Worker, Permanent Alien: An Analysis of Guest Worker Programs in the United States and Canada." Thesis, University of Oregon, 2014. http://hdl.handle.net/1794/18516.
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Over the last several decades, economic globalization has presented many `advanced' economies with a dilemma between facilitating the flow of goods while simultaneously regulating the flow of labor. This contradiction has manifested itself in the immigration policies of Canada and the U.S., which have each pursued distinct strategies for importing foreign workers to maintain global economic competition. Such workers, whether legal `guest workers' or `illegal' immigrants, reside within the boundaries of the state, yet remain permanent aliens. This dissertation explores how guest worker policy specifically and immigration policy more broadly have been constructed and debated in national political discourse from 1990 to 2010. In addition, research in two rural case study communities reveals how labor markets and social geographies are re-shaped by the interaction between workers of varying legal and `illegal' statuses. This multi-scaled and comparative analysis of the understudied issue of guest worker programs reveals how different forms of exclusion, constructed at national and local scales, become deeply interwoven together to produce new labor market realities and reinforce national identities predicated on protecting the composition of the nation while actively promoting global economic competition.
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Ďurkechová, Zuzana. "Návrh na zlepšení marketingového mixu ve vybrané společnosti." Master's thesis, Vysoké učení technické v Brně. Fakulta podnikatelská, 2021. http://www.nusl.cz/ntk/nusl-442966.
Full textAbstract:
The diploma thesis deals with a proposal to improve the marketing mix of the pension with restaurant Koliba pod skalami. The thesis consists of three parts, theoretical part, analytical part and the proposal. The introductory, theoretical part deals with the definitions of basic concepts associated with marketing, marketing mix and forms the theoretical framework of the work. The analytical part of the work deals with the characteristics of the company, a description of the current situation, analysis of the external and internal environment, marketing mix and the results of a questionnaire survey. Based on the results of the analytical part, the proposal part of the thesis contains suggestions for improving the marketing mix.
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Lima, M. "Analysis of advanced glycation end-products (ages) and their impact on gut health." Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517389.
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Philipson, Casandra Washington. "Systems analysis and characterization of mucosal immunity." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/74392.
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During acute and chronic infectious diseases hosts develop complex immune responses to cope with bacterial persistence. Depending on a variety of host and microbe factors, outcomes range from peaceful co-existence to detrimental disease. Mechanisms underlying immunity to bacterial stimuli span several spatiotemporal magnitudes and the summation of these hierarchical interactions plays a decisive role in pathogenic versus tolerogenic fate for the host. This dissertation integrates diverse data from immunoinformatics analyses, experimental validation and mathematical modeling to investigate a series of hypotheses driven by computational modeling to study mucosal immunity. Two contrasting microbes, enteroaggregative Escherichia coli and Helicobacter pylori, are used to perturb gut immunity in order to discover host-centric targets for modulating the host immune system. These findings have the potential to be broadly applicable to other infectious and immune-mediated diseases and could assist in the development of antibiotic-free and host-targeted treatments that modulate tolerance to prevent disease.Ph. D.
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Marschner, Caroline A. "ANALYSIS OF DIETARY OVERLAP BETWEEN YELLOW PERCH (PERCA FLAVESCENS) AND ROUND GOBY (NEOGOBIUS MELANOSTOMUS) IN WESTERN LAKE ERIE THROUGH GUT AND STABLE ISOTOPE ANALYSES." Miami University / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=miami1069365415.
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Makwana, R. "Pharmacological analysis of cannabinoid receptor activity in isolated nerve-smooth muscle and epithelial preparations." Thesis, University of Hertfordshire, 2007. http://hdl.handle.net/2299/1182.
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This study was directed at characterising the cannabinoid receptor activity modulating the electrical field stimulation (EFS) evoked contractions of the rat isolated ileum myenteric plexus longitudinal muscle (MPLM) preparation, and the capsaicin, nicotine and veratridine evoked secretory responses of the rat isolated colonic submucosal plexus-mucosal (SPM) preparation. EFS of the MPLM preparation with single pulses at a repetition frequency of 0.05 Hz elicited a transient twitch contraction immediately in response to each electrical pulse. In contrast, stimulation of the MPLM preparation with 2 second trains of pulses every minute at a frequency of 30 Hz elicited a rapid transient rebound contraction on termination of each train of EFS. The non-selective cannabinoid receptor agonists AEA, CP 55,940, D9-THC and WIN 55,212-2 inhibited both EFS-evoked twitch and rebound contractions of the rat ileum MPLM elicited by 0.05 Hz and 30 Hz EFS respectively. The inhibition of the twitch contractions was competitively antagonised by the cannabinoid CB1 receptor antagonist / inverse agonist SR 141716 with pKB values of 8.60. In contrast, SR 141716 only antagonised the ability of AEA, D9-THC and WIN 55,212-2 but not CP 55,940 to inhibit the rebound contractions with pA2 values of 6.60. These observations extended to the inhibitory effect of WIN 55,212-2 on the twitch and rebound contractions of the guinea-pig ileum MPLM. The CB2 antagonist / inverse agonist SR 144528 did not alter the effects of the agonists. Additionally, the inhibitory effect of AEA was refractory to the vanilloid TRPV1 receptor antagonist capsazepine. WIN 55,212-3 a stereoisomer of WIN 55,212-2 was without effect on the rat MPLM. SR 141716 alone concentration-dependently increased the twitch contractions but inhibited the rebound contractions. Both types of the EFS-evoked contractions were abolished by the Na+ channel blocker tetrodotoxin or the muscarinic acetylcholine (ACh) receptor antagonist atropine but not the nicotinic ACh receptor antagonist hexamethonium. None of the cannabinoids altered the contractions to exogenously applied ACh. These data suggested that the cannabinoid agonists inhibited the twitch contractions through a stereospecific presynaptic CB1 receptor-mediated reduction in the release of ACh. Additionally, the inhibition of the rebound contractions occurred because of an inhibition of ACh release by a novel stereospecific presynaptic non-CB1 -non CB2 -non -TRPV1 site. The ability of SR 141716 to inhibit the rebound contractions and antagonise AEA, D9-THC and WIN 55,212-2 may be though partial agonism at the non-CB1-non CB2-non-TRPV1 site. The ability of SR 141716 to potentiate the twitch contractions by increasing the release of ACh suggested that the CB1 receptor was constitutively active or was subjected to a tonic activation by endocannabinoid agonists. A comparison between the maximal enhancement of the twitch contractions of the rat and the guinea-pig ileum MPLM caused by three CB1 receptor antagonists/inverse agonists AM 251, SR 141716 and O-2050 showed that each cannabinoid had a different maximum. This suggested inverse agonism. These data were supported with studies showing the lack of effect of three fatty acid amide hydrolase (FAAH) inhibitors AA-5HT, PMSF, URB–597 and VDM-11, an inhibitor of the AEA uptake transporter on EFS-evoked contractions. These studies showed that all three FAAH inhibitors increased the potency of exogenously applied AEA but not WIN 55,212-2, and that VDM-11 had no effect on the potency of exogenously applied AEA. This data suggested that a functional endocannabinoid tone and the uptake transporter were not present in the MPLM, but FAAH was present. These data provide supporting evidence that SR 141716 behaved as an inverse agonist in the MPLM to augment twitch contractions. The interaction between CP 55,940 or WIN 55,212-2 with SR 141716 was investigated using the rat colonic SPM sheet. Both CP 55,940 and WIN 55,212-2 attenuated the secretory responses to capsaicin and nicotine in a SR 141716 sensitive manner. SR 140333, a neurokinin 1 receptor antagonist, abolished the capsaicin and nicotine. This suggested that CP 55,940 and WIN 55,212-2 inhibited the capsaicin and nicotine response through a CB1 receptor-mediated inhibition of the release of substance P or neurokinin A. The sensitivity of the veratridine response to TTX and a-chymotrypsin and the failure of the cannabinoids to attenuate the response suggested the absence of the CB1 receptor on the neurones releasing the undetermined neuropeptide. Together, these data suggest that both the CB1 receptor and non-CB1-non-CB2 -non-TRPV1 receptor can mediate the inhibitory effects of cannabinoid agonists in the rat ileum MPLM depending on the frequency of EFS. These data also show that SR 141716 is an inverse agonist in the MPLM. In the SPM preparation, the CB1 receptor appears to be involved in the modulation of some forms of peptidergic transmission.
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Haines, Lauren E. "Mesenchymal Analysis of Human Pluripotent Stem Cell-Derived Gastrointestinal Organoids." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563873084551926.
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Blom, Magnus. "Light-Triggered Conformational Switches for Modulation of Molecular Recognition : Applications for Peptidomimetics and Supramolecular Systems." Doctoral thesis, Uppsala universitet, Syntetisk organisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267845.
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The main focus of this thesis is on photochemical modulation of molecular recognition in various host-guest systems. This involves the design, synthesis and integration of light-triggered conformational switches into peptidomimetic guests and molecular tweezer hosts. The impact of the switches on guest and host structures has been assessed by spectroscopic and computational conformational analysis. Effects of photochemical structure modulation on molecular recognition in protein-ligand and supramolecular host-guest systems are discussed. Phototriggerable peptidomimetic inhibitors of the enzyme M. tuberculosis ribonucleotide reductase (RNR) were obtained by incorporation of a stilbene based amino acid moiety into oligopeptides between 3-9 residues long (Paper I). Interstrand hydrogen bond probability in the E and Z forms of the peptidomimetics was used as a tool for predicting conformational preferences. Considerable differences in inhibitory potency for the E and Z photoisomers were demonstrated in a binding assay. In order to advance the concept of photomodulable inhibitors, synthetic routes towards amino acid derivatives based on the more rigid stiff-stilbene chromophore were developed (Paper II). The effect of E-Z isomerization on the conformational properties of peptidomimetic inhibitors incorporating the stiff-stilbene chromophore was also assessed computationally (Paper III). It was indicated that inhibitors with the more rigid amino acid derivative should display larger conformational divergence between photoisomers than corresponding stilbene derivatives. Bisporphyrin tweezers with enediyne and stiff-stilbene spacers have been synthesized, and the conformational characteristics imposed by the spacers have been studied and compared to a glycoluril linked tweezer. The effects of spacers on tweezer binding of diamine guests and helicity induction by chiral guests have been investigated (Paper IV). Connections between spacer flexibility and host-guest binding strength have been established. The structural properties of the stiff-stilbene spaced tweezer made it particularly susceptible to helicity induction by both monotopic and bitopic chiral guests. Finally, the possibility of photochemical bite-size variation of tweezers with photoswitchable spacers has been assessed. Initial studies have shown that photoisomerization of the tweezers is possible without photochemical decomposition. Conformational analyses indicate that isomerization should impact binding characteristics of the tweezers to a significant extent (Paper V).
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Wickey, Jessica. "Guest Satisfaction Analysis of a Casual Dining Restaurant: A comparison of tourist VS non-tourist satisfaction scores." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6035.
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Purpose - The purpose of this study is to analyze guest/customer satisfaction surveys of a casual dining restaurant in the Orlando, Florida area; specifically, to analyze if there is a difference between satisfaction levels of tourist and non-tourist guests.
The guest satisfaction surveys were analyzed on eight dimensions of satisfaction; Pace of Service, Service Overall, Server Communication & Accuracy, Food (Taste & Quality), Food Preparation, Bar (Beer, Wine, & Cocktail), Gratefulness, and Atmosphere in whole (including atmosphere and cleanliness).The eight dimensions were evaluated in the GPS (guest pulse survey) based on a Net Promoter Score, or NPS&"174; system, and were compared by guest type: tourist versus non-tourist. Multiple linear regression analyses results concluded that the dimensions of Pace, Service Overall, Food, Food Preparation, and Atmosphere were predicators of Overall Satisfaction for tourist respondents. Service Overall, Server Communication, and Gratefulness were predictors of Overall Satisfaction for non-tourist respondents.M.S.
Masters
Hospitality Services
Hospitality Management
Hospitality and Tourism Management
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Collison, Matthew Geoffrey. "Human-microbiota interactions in health and disease : bioinformatics analyses of gut microbiome datasets." Thesis, University of Newcastle upon Tyne, 2018. http://hdl.handle.net/10443/4154.
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The human gut harbours a vast diversity of microbial cells, collectively known as the gut microbiota, that are crucial for human health and dysfunctional in many of the most prevalent chronic diseases. Until recently culture dependent methods limited our ability to study the microbiota in depth including the collective genomes of the microbiota, the microbiome. Advances in culture independent metagenomic sequencing technologies have since provided new insights into the microbiome and lead to a rapid expansion of data rich resources for microbiome research. These high throughput sequencing methods and large datasets provide new opportunities for research with an emphasis on bioinformatics analyses and a novel field for drug discovery through data mining. In this thesis I explore a range of metagenomics analyses to extract insights from metagenomics data and inform drug discovery in the microbiota. Firstly I survey the existing technologies and data sources available for data mining therapeutic targets. Then I analyse 16S metagenomics data combined with metabolite data from mice to investigate the treatment model of a proposed antibiotic treatment targetting the microbiota. Then I investigate the occurence frequency and diversity of proteases in metagenomics data in order to inform understanding of host-microbiota-diet interactions through protein and peptide associated glycan degradation by the gut microbiota. Finally I develop a system to facilitate the process of integrating metagenomics data for gene annotations. One of the main challenges in leveraging the scale of data availability in microbiome research is managing the data resources from microbiome studies. Through a series of analytical studies I used metagenomics data to identify community trends, to demonstrate therapeutic interventions and to do a wide scale screen for proteases that are central to human-microbiota interactions. These studies articulated the requirement for a computational framework to integrate and access metagenomics data in a reproducible way using a scalable data store. The thesis concludes explaining how data integration in microbiome research is needed to provide the insights into metagenomics data that are required for drug discovery.
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Aldis, Gary. "Analysis of the infant gut microbiota and investigation of bifidobacterial diversity and anti-microbial activity." Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.632825.
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Selected bacterial groups within the infant gut micro biota were investigated in relation to mode of delivery, initial diet (i.e. breast-fed versus formula-fed) and weaning. Colonic bacteria from 50 faecal samples (obtained from 30 infants during the milk-fed and, post-weaning phases) were enumerated by fluorescence in situ hybridisation. The probes used were as follows: Bac 303 (bacteroides), Bif 164 (bifidobacteria), Chis 150 (Clostridium clusters I and II), Erec 482 (Clostridium cluster XIVa), EC 1531 (Escherichia coli), Lab 158 (lactobacilli/enterococci group) and the DAPI nucleic acid stain (total cell count). In all cases bifidobacteria were identified as the major group. The mode of delivery did not influence the composition of the gut microbiota. Exclusively breast-fed infants had significantly lower Clostridium cluster XIVa counts than those exclusively formula-fed. Infants fed predominantly breast-milk had significantly lower Clostridium cluster XIVa, and higher total and bifidobacterial counts than predominantly formula-fed infants. Amongst the samples obtained following the introduction of solid food, no differences were observed following segregation into original cohorts (of delivery mode and initial diet). Furthermore, such faecal samples had significantly lower E. coli, total bacterial and bifidobacterial counts than those obtained during the milk-fed phase. Subsequently, the bifidobacterial component was further examined in relation to diversity and anti-microbial activity. Predominant biotypes (as determined by genetic fingerprinting of isolates) were identified by partial16S rRNA gene sequencing as five recognised bifidobacterial species, novel Bifidobacterium spp., Enterococcus faecalis and Lactobacillus plantarum. B. breve was the principle species isolated. However the bifidobacterial composition differed between infant cohorts.
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Hu, Mirko. "Network analysis of a complex disease: the gut microbiota in the inflammatory bowel disease case." Thesis, IMT Alti Studi Lucca, 2022. http://e-theses.imtlucca.it/353/1/Hu_phdthesis.pdf.
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The gut microbiota contains hundreds of types of microbes
and dysbiosis can lead to infammatory bowel diseases (IBD),
which comprise Crohn’s disease (CD) and ulcerative colitis
(UC). Due to the complex nature of the IBD, it is interest-
ing to understand the differences between a control (NI) and
an IBD gut microbiome by using new tools offered by net-
work science. In particular, when metagenomic data are con-
sidered, it is possible to build networks according to the co-variance, the co-occurrence and multiple layers of networks(multilayer networks). In addition to the construction of the
networks, an analysis of the differential expressed pathways
is carried out, several centrality measures are calculated, and community detection is performed to explore the topological differences between the diagnosis networks. The analysis of the correlation network topology highlights that, in IBD net-works, the pathway involving coenzyme A of the unclassifed species becomes central. Furthermore, the modularity in the IBD networks is higher. In both the correlation network and the co-occurrence network, the modules belonging to B. ova-tus and B. caccae are positioned differently in each diagnosis.
Furthermore, the difference between the NI and the UC diag-
nosis networks lies in a change in the wiring that preserves
the centralities. Moreover, the fundamental role of two of the Roseburia species in the NI is evidenced. A further step will consist of identifying the minimum number of pathways on which it would be ideal to intervene to drive the system back to a healthy state by the precision medicine way of operating.
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Cariani, Alessia <1979>. "Development and use of DNA microarray platform for gut content analysis and microbial pathogen identification." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1741/1/AlessiaCariani_PhD.pdf.
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Cariani, Alessia <1979>. "Development and use of DNA microarray platform for gut content analysis and microbial pathogen identification." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1741/.
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Wuttke, Axel. "Computational Study of Dispersion Interactions through Local Orbital Analysis." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/11858/00-1735-0000-002E-E606-7.
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Li, Chi-kwan, and 李志君. "Gold(I) and Gold(II) phosphine complexes exhibiting weak AuI... AuI interactions and unsupported AuII-AuII bonds: syntheses, spectroscopy, host-guest chemistry and reactivity studies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31243332.
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Wojciak, Johannes D. [Verfasser], Nikolaus A. [Akademischer Betreuer] Adams, and Christian J. [Akademischer Betreuer] Kähler. "Quantitative Analysis of Vehicle Aerodynamics during Crosswind Gusts / Johannes Wojciak. Gutachter: Christian J. Kähler. Betreuer: Nikolaus A. Adams." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1029818932/34.
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Lynch, Christine Ann. "Exploring consumption by two generalist predators in potatoes using molecular gut content analysis and behavioral studies." Thesis, Washington State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3587135.
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Molecular gut-content analysis is an established and increasingly important approach for tracking arthropod predation in the field. Previously, it is difficult to know what hemipteran generalist predators consume because there are no pieces of prey in their gut that could be identified following dissection. However, DNA of the prey item is present in a predator's gut for a certain amount of time. In order to relate the proportion of predator individuals found to contain pest DNA to the number of pests eaten over a given time period, it is necessary to determine how long pest DNA can be detected after predation has occurred. Studies were done to explore consumption of Geocoris and Nabis with green peach aphids and Colorado potato beetles.
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Johnston, Stephanie Lauren. "Identification of multigene cysteine protease gene families in Haemonchus contortus and analysis of gut gene expression." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3735/.
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Haemonchus contortus is a blood-feeding Strongylid parasite that is economically significant worldwide. Due to the increasing problem of anthelmintic resistance, alternative approaches are urgently required for parasitic nematode control. H. contortus cathepsin B gut cysteine proteases have received attention as potential vaccine candidates because of their proposed role in blood feeding. The increasing amount of H. contortus genome information has now enabled detailed identification and annotation of cathepsin B protease gene families. In this study H. contortus BAC 18f22 was annotated and found to encode eight tandemly arranged cysteine proteases related to the previously identified AC family, but with six novel genes identified. Annotation of supercontig and scaffold sequence identified many more members of the HmCP and GCP-7 cathepsin B families. In total this work has shown that the H. contortus genome encodes at least 41 cathepsin B protease genes, more than in other nematodes, to date. In contrast, Hc-cpr-6 is present as a single copy gene that is highly conserved in a number of species, suggesting an important conserved function. Further work examined regulation of gut gene expression in H. contortus, in particular the H. contortus ELT-2 GATA transcription factor (TF), as it has been shown to be the major TF in C. elegans controlling gut gene expression. A high throughput assay was developed and used to screen an integrated C. elegans worm strain expressing GFP in the gut and hypodermis (Ce-cpl-1::gfp) against 594 chemical compounds. Compounds were identified that specifically cause a decrease in gut GFP expression, affect larval development and show a degree of lethality. Further work on two of the compounds identified an embryonic effect, with a significant decrease in number of progeny. To conclude, this thesis identified a number of novel cathepsin B genes as well as two compounds potentially interfering with TF activity and gut gene expression which may be of use as novel anthelmintics.
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Stämmler, Frank Michael Nikolaus [Verfasser], and Rainer [Akademischer Betreuer] Spang. "Standardisation and optimisation techniques in gut microbiome community analysis / Frank Michael Nikolaus Stämmler ; Betreuer: Rainer Spang." Regensburg : Universitätsbibliothek Regensburg, 2020. http://d-nb.info/1204635862/34.
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Guse, Björn Felix [Verfasser], and Bruno [Akademischer Betreuer] Merz. "Improving flood frequency analysis by integration of empirical and probabilistic regional envelope curves / Björn Felix Guse ; Betreuer: Bruno Merz." Potsdam : Universität Potsdam, 2010. http://d-nb.info/1218391049/34.
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Hladilek, Erin Elizabeth. "THE ROLE OF SPIDERS IN THE DETRITAL FOOD WEB OF AN EASTERN DECIDUOUS FOREST." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/682.
Full textAbstract:
Historically, terrestrial food web research has focused on describing the structure of aboveground grazing webs, and determining how interactions among plants, herbivores and higher trophic levels influence primary productivity. Detrital food webs however, play a significant role in regulation of ecosystem dynamics through direct impacts on decomposition. Unraveling the complex nature of detrital food web structure is critical to developing a better understanding of ecosystem function. Therefore the primary objective of this research was to describe the structure of the leaf-litter food web in a temperate deciduous forest, with emphasis on interactions between a community of generalist predators, the forest-floor spiders, and arthropod prey.
Elucidating occurrence of trophic interactions in the forest-floor food web was a formidable task due to the high diversity, small body sizes and cryptic habits of many litter-dwelling arthropods. Analysis of natural variation in consumer stable isotope ratios (δ13C and δ15N) formed the crux of this research because it simultaneously permitted quantification of the trophic positions of litterdwelling arthropods and identification of spider resources, including prey subsidies from the grazing web. A monoclonal antibody-based ELISA was employed to analyze the gut contents of spiders to quantify predation on a major arthropod taxon, the forest-floor flies. Surveys of spider distributions and prey availability in the litter layer also provided fundamental knowledge of community structure.
Stable isotope analyses suggested that most spiders exhibited strong trophic connections to the detrital web, but weak links to herbivorous prey. Several lines of evidence supported a strong trophic link between large, litterdwelling collembolans (Tomoceridae) and cursorial spiders, including correlation between spider and tomocerid densities on the forest-floor, similarities in spider and tomocerid carbon signatures, and nitrogen enrichment of tomocerids relative to other prey types. Conversely, this research provided conflicting evidence regarding spider consumption of flies. Gut content assays indicated consistent predation on flies by cursorial spiders, while stable isotope models suggested that flies are likely of little importance in the spiders’ diets. This project yielded valuable insights into the role of spiders in the forest-floor food web and the potential importance of species-specific variation in prey consumption for detrital food web dynamics.
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Botha, Jonathan. "Qualitative GUS and targeted yeast one-hybrid analyses of the Eucalyptus grandis SND2 promoter region." Diss., University of Pretoria, 2013. http://hdl.handle.net/2263/79297.
Full textAbstract:
The secondary cell walls of woody plant species are a major source of cellulose. This biopolymer is among the most abundant on the planet and is very useful to industry, having many applications, such as in the paper industry and as a possible source of fermentable sugar for biofuel production. Therefore, much emphasis is placed on understanding the formation of woody biomass (mainly comprising of secondary cell walls) as a possible feedstock for cellulose extraction. Wood fibres are of particular interest as they are most useful for the paper industry and have thick, cellulose rich secondary cell walls. Transcriptional regulation of secondary cell wall biosynthesis is facilitated through a complex network of proteins and genes operating in a semi-hierarchical manner. In xylem, each cell type is controlled by a "master switch", a transcription factor (TF) which is able to activate the entire secondary cell wall biosynthetic program for that particular cell type. In Arabidopsis xylem fibres, SECONDARY WALL ASSOCIATED NAC DOMAIN PROTEIN1 (SND1) is the master regulator for secondary cell wall deposition. Overexpression of SND1 results in the upregulation of a number TFs important for secondary cell wall biosynthesis. Three of the upregulated TFs were able to induce expression of a reporter gene under the control of a cellulose synthase (AtCesA8) promoter, indicating these TFs may be involved in cellulose biosynthesis. Of these, only SECONDARY WALL ASSOCIATED NAC DOMAIN PROTEIN2 (SND2) is not a direct target of SND1. While much work has been done on the regulatory network in the model plant Arabidopsis, there are still major gaps in our understanding. Comparatively little work has been done to study this network in hardwood crop tree species such as Eucalyptus grandis. Properly characterising and understanding this network will allow us to manipulate hardwood crops to obtain trees with commercially desirable traits and will also provide a platform for future studies in the field of transcriptional regulation of wood formation.Dissertation (MSc)--University of Pretoria, 2013.
Genetics
MSc
Unrestricted
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Zheng, Hongjun. "Nutrient acquisition in a human gut symbiont : molecular analysis of the carbohydrate utilisation apparatus of Bacteroides thetaiotaomicron." Thesis, University of Newcastle Upon Tyne, 2009. http://hdl.handle.net/10443/275.
Full textAbstract:
The gut microbiota play a significant role in human health and nutrition, although the mechanisms these organisms use to survive in this densely populated environment are not well understood. Bacteroides thetaiotaomicron is a dominant member of the gut bacterial community whose genome sequence reveals large expansions in protein families involved in the sensing, acquisition and utilisation of complex carbohydrates, pointing to the ability to access a wide range of glycans as playing a significant role in becoming a successful resident of the human gut. Here we have characterised components of the B. thetaiotaomicron polysaccharide utilisation apparatus at molecular level, focusing mainly on fructan sensing, binding and degradation systems. Microarray data from our collaborators revealed that growth of B. thetaiotaomicron on inulin (β-2,1-linked fructan) specifically upregulated a locus of nine genes BT1757-BT1765 and an orphan gene BT3082, encoding a glycoside hydrolase from family 32 (GH32). The locus contains three other GH32s, two predicted polysaccharide binding outer membrane proteins (SusC and SusD homologues), a fructokinase, and an inner membrane monosaccharide transporter. Together these components form a polysaccharide utilisation locus (PUL). The nearest regulatory gene to the PUL is BT1754, a hybrid two component system. Here we show that the periplasmic sensor domain of BT1754 (BT1754peri) binds specifically to fructose, with a Kd of ~2 μM and a stoichiometry of 1:1, but not fructooligosaccharides or other monosaccharides. The crystal structure of BT1754peri revealed a two domain periplasmic binding protein (PBP)-fold with the ligand fructose sandwiched between the two domains. BT1754 is the first periplasmic sensor histidine kinase domain to display a non-PAS fold. The structure in combination with biophysical and site-directed mutagenesis studies also shows how the protein displays such specificity in ligand recognition and provides insights into the mechanism of signal transduction across the inner membrane. The four glycoside hydrolase family 32 members regulated by BT1754 were also biochemically and structurally characterised in this thesis. Three of four GH32 enzymes BT1759, BT1765 and BT3082, digest both β-2,1-linked (inulin) and β-2,6-linked (levan) fructans, indicating that levan is also utilised by the same locus. BT1759 and BT3082 are exo-acting enzymes releasing fructose from both long-chain and short-chain inulins and levans, while BT1765 is also exo-acting and produces fructose, but preferred short-chain sugars. BT1760 is unusual for GH32 as it is specific for levan and has an endo-like activity, releasing a range of different size oligosaccharides from the polysaccharide. The crystal structures of wild type BT3082 and a nucleophile mutant in complex with substrate (kestose) were solved to 2.2 Å and revealed a typical GH32 β-propeller fold as the catalytic domain. Like all other GH32s solved to date, the enzyme has a C-terminal β-sheet domain of unknown function that was shown to be necessary for correct folding of the enzyme. BT3082 also has a unique N-terminal β-sheet domain that was shown to be essential for enzyme activity but not correct folding. Extensive site-directed mutagenesis was carried out to provide insight into the relative importance of different residues in substrate binding and catalysis in BT3082. The crystal structure of wild type BT1760 was solved to 2.6 Å, revealing a surprisingly similar structure to that of the exo-acting enzymes. A rationale for the endo-like activity of this enzyme and the role each of the four GH32s in fructan utilisation by B. thetaiotaomicron is discussed. The outer membrane SusD homologue BT1762 from the fructan locus was shown to bind preferentially to long chain levans, with no recognition of inulin. The crystal structure of BT1762 was solved to 1.9 Å and was shown to share the same novel α-helical fold as SusD. Site-directed mutagenesis of a number of residues in the same region as the SusD binding site showed that while the location of the ligand binding sites are conserved between these two proteins, the identity of the residues involved in polysaccharide recognition are not the same. A model is proposed for levan recognition in BT1762 and also its role in polysaccharide utilisation. B. thetaiotaomicron also has at least 12 ECF sigma/anti-sigma factor gene pairs likely involved in polysaccharide utilisation. Here we show that these systems form a trans-envelope signalling apparatus with their cognate SusC-transducer homologue, but that there is no cross talk between different systems. The significance of this finding in relation to survival of this important gut bacterium is discussed.