942 resultados para nested-PCR_
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A new Coastal Rapid Environmental Assessment (CREA) strategy has been developed and successfully applied to the Northern Adriatic Sea. CREA strategy exploits the recent advent of operational oceanography to establish a CREA system based on an operational regional forecasting system and coastal monitoring networks of opportunity. The methodology wishes to initialize a coastal high resolution model, nested within the regional forecasting system, blending the large scale parent model fields with the available coastal observations to generate the requisite field estimates. CREA modeling system consists of a high resolution, O(800m), Adriatic SHELF model (ASHELF) implemented into the Northern Adriatic basin and nested within the Adriatic Forecasting System (AFS) (Oddo et al. 2006). The observational system is composed by the coastal networks established in the framework of ADRICOSM (ADRiatic sea integrated COastal areaS and river basin Managment system) Pilot Project. An assimilation technique exerts a correction of the initial field provided by AFS on the basis of the available observations. The blending of the two data sets has been carried out through a multi-scale optimal interpolation technique developed by Mariano and Brown (1992). Two CREA weekly exercises have been conducted: the first, at the beginning of May (spring experiment); the second in middle August (summer experiment). The weeks have been chosen looking at the availability of all coastal observations in the initialization day and one week later to validate model results, verifying our predictive skills. ASHELF spin up time has been investigated too, through a dedicated experiment, in order to obtain the maximum forecast accuracy within a minimum time. Energetic evaluations show that for the Northern Adriatic Sea and for the forcing applied, a spin-up period of one week allows ASHELF to generate new circulation features enabled by the increased resolution and its total kinetic energy to establish a new dynamical balance. CREA results, evaluated by mean of standard statistics between ASHELF and coastal CTDs, show improvement deriving from the initialization technique and a good model performance in the coastal areas of the Northern Adriatic basin, characterized by a shallow and wide continental shelf subject to substantial freshwater influence from rivers. Results demonstrate the feasibility of our CREA strategy to support coastal zone management and wish an additional establishment of operational coastal monitoring activities to advance it.
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While the use of distributed intelligence has been incrementally spreading in the design of a great number of intelligent systems, the field of Artificial Intelligence in Real Time Strategy games has remained mostly a centralized environment. Despite turn-based games have attained AIs of world-class level, the fast paced nature of RTS games has proven to be a significant obstacle to the quality of its AIs. Chapter 1 introduces RTS games describing their characteristics, mechanics and elements. Chapter 2 introduces Multi-Agent Systems and the use of the Beliefs-Desires-Intentions abstraction, analysing the possibilities given by self-computing properties. In Chapter 3 the current state of AI development in RTS games is analyzed highlighting the struggles of the gaming industry to produce valuable. The focus on improving multiplayer experience has impacted gravely on the quality of the AIs thus leaving them with serious flaws that impair their ability to challenge and entertain players. Chapter 4 explores different aspects of AI development for RTS, evaluating the potential strengths and weaknesses of an agent-based approach and analysing which aspects can benefit the most against centralized AIs. Chapter 5 describes a generic agent-based framework for RTS games where every game entity becomes an agent, each of which having its own knowledge and set of goals. Different aspects of the game, like economy, exploration and warfare are also analysed, and some agent-based solutions are outlined. The possible exploitation of self-computing properties to efficiently organize the agents activity is then inspected. Chapter 6 presents the design and implementation of an AI for an existing Open Source game in beta development stage: 0 a.d., an historical RTS game on ancient warfare which features a modern graphical engine and evolved mechanics. The entities in the conceptual framework are implemented in a new agent-based platform seamlessly nested inside the existing game engine, called ABot, widely described in Chapters 7, 8 and 9. Chapter 10 and 11 include the design and realization of a new agent based language useful for defining behavioural modules for the agents in ABot, paving the way for a wider spectrum of contributors. Chapter 12 concludes the work analysing the outcome of tests meant to evaluate strategies, realism and pure performance, finally drawing conclusions and future works in Chapter 13.
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Two Amerindian populations from the Peruvian Amazon (Yanesha) and from rural lowlands of the Argentinean Gran Chaco (Wichi) were analyzed. They represent two case study of the South American genetic variability. The Yanesha represent a model of population isolated for long-time in the Amazon rainforest, characterized by environmental and altitudinal stratifications. The Wichi represent a model of population living in an area recently colonized by European populations (the Criollos are the population of the admixed descendents), whose aim is to depict the native ancestral gene pool and the degree of admixture, in relation to the very high prevalence of Chagas disease. The methods used for the genotyping are common, concerning the Y chromosome markers (male lineage) and the mitochondrial markers (maternal lineage). The determination of the phylogeographic diagnostic polymorphisms was carried out by the classical techniques of PCR, restriction enzymes, sequencing and specific mini-sequencing. New method for the detection of the protozoa Trypanosoma cruzi was developed by means of the nested PCR. The main results show patterns of genetic stratification in Yanesha forest communities, referable to different migrations at different times, estimated by Bayesian analyses. In particular Yanesha were considered as a population of transition between the Amazon basin and the Andean Cordillera, evaluating the potential migration routes and the separation of clusters of community in relation to different genetic bio-ancestry. As the Wichi, the gene pool analyzed appears clearly differentiated by the admixed sympatric Criollos, due to strict social practices (deeply analyzed with the support of cultural anthropological tools) that have preserved the native identity at a diachronic level. A pattern of distribution of the seropositivity in relation to the different phylogenetic lineages (the adaptation in evolutionary terms) does not appear, neither Amerindian nor European, but in relation to environmental and living conditions of the two distinct subpopulations.
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Phylogeography is a recent field of biological research that links phylogenetics to biogeography through deciphering the imprint that evolutionary history has left on the genetic structure of extant populations. During the cold phases of the successive ice ages, which drastically shaped species’ distributions since the Pliocene, populations of numerous species were isolated in refugia where many of them evolved into different genetic lineages. My dissertation deals with the phylogeography of the Woodland Ringlet (Erebia medusa [Denis and Schiffermüller] 1775) in Central and Eastern Europe. This Palaearctic butterfly species is currently distributed from central France and south eastern Belgium over large parts of Central Europe and southern Siberia to the Pacific. It is absent from those parts of Europe with mediterranean, oceanic and boreal climates. It was supposed to be a Siberian faunal element with a rather homogeneous population structure in Central Europe due to its postglacial expansion out of a single eastern refugium. An already existing evolutionary scenario for the Woodland Ringlet in Central and Eastern Europe is based on nuclear data (allozymes). To know if this is corroborated by organelle evolutionary history, I sequenced two mitochondrial markers (part of the cytochrome oxydase subunit one and the control region) for populations sampled over the same area. Phylogeography largely relies on the construction of networks of uniparentally inherited haplotypes that are compared to geographic haplotype distribution thanks to recent developed methods such as nested clade phylogeographic analysis (NCPA). Several ring-shaped ambiguities (loops) emerged from both haplotype networks in E. medusa. They can be attributed to recombination and homoplasy. Such loops usually avert the straightforward extraction of the phylogeographic signal contained in a gene tree. I developed several new approaches to extract phylogeographic information in the presence of loops, considering either homoplasy or recombination. This allowed me to deduce a consistent evolutionary history for the species from the mitochondrial data and also adds plausibility for the occurrence of recombination in E. medusa mitochondria. Despite the fact that the control region is assumed to have a lack of resolving power in other species, I found a considerable genetic variation of this marker in E. medusa which makes it a useful tool for phylogeographic studies. In combination with the allozyme data, the mitochondrial genome supports the following phylogeographic scenario for E. medusa in Europe: (i) a first vicariance, due to the onset of the Würm glaciation, led to the formation of several major lineages, and is mirrored in the NCPA by restricted gene flow, (ii) later on further vicariances led to the formation of two sub-lineages in the Western lineage and two sub-lineages in the Eastern lineage during the Last Glacial Maximum or Older Dryas; additionally the NCPA supports a restriction of gene flow with isolation by distance, (iii) finally, vicariance resulted in two secondary sub-lineages in the area of Germany and, maybe, to two other secondary sub-lineages in the Czech Republic. The last postglacial warming was accompanied by strong range expansions in most of the genetic lineages. The scenario expected for a presumably Siberian faunal element such as E. medusa is a continuous loss of genetic diversity during postglacial westward expansion. Hence, the pattern found in this thesis contradicts a typical Siberian origin of E. medusa. In contrast, it corroboratess the importance of multiple extra-Mediterranean refugia for European fauna as it was recently assumed for other continental species.
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In the marine Jurassic deposits of Europe, a group of marine crocodilians, the Thalattosuchia, belongs to the frequently found reptiles. Thalattosuchia are widely spread in Central Europe from the Jurassic to Lower Cretaceous, and some taxa are also distributed worldwide. The task of the work was to examine all taxa known from the Liassic of Europe. The most frequently known taxa Steneosaurus bollensis and Pelagosaurus typus are anatomically revised. New discoveries at the skull of Pelagosaurus typus e.g., the fact of a partly paired frontal are described by means of computed tomography investigations. In addition, juvenile specimens of this taxon are studied in detail for the first time. The rarely occurring taxon Platysuchus multiscrobiculatus is anatomically described in detail for the first time. It shows both in the skull and in the postcranial material morphological differences to Steneosaurus bollensis and Pelagosaurus typus. Thus Pl. multiscrobiculatus possesses, e.g., an ilium with a deeper acetabulum and a femur with a distinctly flexed femoral head. A juvenile specimen of Pl. multiscrobiculatus is now discovered and is described in parts for the first time, too. Furthermore, Steneosaurus gracilirostris and Steneosaurus brevior known from Lower Jurassic deposits of England are examined and in parts revised. In this work, Steneosaurs brevior is discovered with one specimen from the Upper Liassic of Holzmaden, Germany for the first time, and provides new evidence for the palaeobiogeographical distribution of the taxon. Because of the high number of investigated specimens, it is possible to study ontogenetic development from juvenile to adult stage in Steneosaurus bollensis, Pelagosaurus typus, and Platysuchus multiscrobiculatus. Biometric data are collected from thalattosuchians and extant crocodilians (e.g. Gavialis gangeticus) to investigate intraspecific variation, ontogenetic development, and taxa differentiation. The skulls of Platysuchus multiscrobiculatus and Steneosaurus bollensis are reconstructed three-dimensionally as wax models. The skull reconstructions form the basis of the jaw muscle restoration of Steneosaurus bollensis in connection with comparative studies at extant crocodilians. By means of functional morphologic analysis of the jaw musculature, the dentition, and the locomotor system of S. bollensis, possible conclusions are drawn for the prey options and the hunting behaviour. To clarify the relationships within the Thalattosuchia, a computer-based cladistic phylogenetic in-group analyse of 25 Thalattosuchia taxa is performed. For the analysis, following Thalattosuchia taxa are studied likewise at original material for comparisons: Metriorhynchus superciliosus, Metriorhynchus hastifer, Metriorhynchus leedsi, Geosaurus gracilis, Geosaurus giganteus, Teleidosaurus calvadosi, Teleidosaurus gaudryi, Teleosaurus cadomensis, Teleosaurus geoffroyi, Steneosaurus priscus, Steneosaurus edwardsi, Steneosaurus heberti, Steneosaurus leedsi, Steneosaurus boutilieri, Steneosaurus megarhinus, Steneosaurus obtusidens, and Machimosaurus hugii. The phylogenetic in-group analyse based on 115 characters, reveals a sister-group relationship of the monophyletic Teleosauridae and monophyletic Metriorhynchidae. Within the groups, some taxa are probably paraphyletic. The taxon Pelagosaurus typus is nested inside the Teleosauridae and not outside or within the Metriorhynchidae, as many authors suggested it so far. Based on these results, a tentative palaeobiogeographical-evolutionary scenario is developed.
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Das Wachstum von Milchsäurebakterien-Arten der Gattungen Lactobacillus, Pediococcus und Leuconostoc während der Weinfermentation kann durch die Bildung verschiedener Stoffwechselprodukte zu Weinfehlern führen. Um rechtzeitig Gegenmaßnahmen ergreifen zu können und einem Weinverderb vorzubeugen, bedarf es geeigneter Identifizierungsmethoden. Klassische mikrobiologische Methoden reichen oft nicht aus, um Mikroorganismen auf Art- und Stammniveau gezielt zu identifizieren. Wegen ihrer schnellen Durchführbarkeit und Zuverlässigkeit sind molekularbiologische Identifizierungsmethoden zur Kontrolle der mikrobiellen Flora während der Lebensmittelfermentierung in der heutigen Zeit unabdingbar. In der vorliegenden Forschungsarbeit wurden die 23S rRNA-Gensequenzen von neun Pediococcus-Typstämmen sequenziert, analysiert und phylogenetische Analysen durchgeführt. Zur Art-Identifizierung der Pediokokken wurden PCR-Primer generiert und ein Multiplex PCR System entwickelt, mit dem alle typischen Arten simultan in einer Reaktion nachgewiesen werden konnten. Die Ergebnisse der Multiplex PCR-Identifizierung von 62 Pediococcus-Stämmen aus Kulturensammlungen und 47 neu isolierten Stämmen aus Wein zeigten, dass einige Stämme unter falschen Artnamen hinterlegt waren, und dass P. parvulus im Weinanbaugebiet Rheinhessen weit verbreitet war. Die Fähigkeit der Pediococcus-Stämme zur Exopolysaccharid-Synthese wurde durch den Nachweis zweier Gene überprüft. Auf Basis der 23S rDNA-Sequenzen wurden rRNA-Sekundärstrukturen mit der neu entwickelten Software Structure Star generiert, die zum Auffinden von Zielbereichen für fluoreszenzmarkierte DNA-Sonden geeignet waren. Die Sequenzunterschiede zwischen den Pediococcus-Arten reichten aus, um zwei Gruppen durch Fluoreszenz in situ Hybridisierung differenzieren zu können. Die Verwendung unmarkierter Helfer-sonden verbesserte die Zugänglichkeit der Sonden an die rRNA, wodurch das Fluoreszenz-Signal verstärkt wurde. Um Milchsäurebakterien durch Denaturierende Gradienten Gel Elektrophorese differenzieren zu können, wurden Primer entwickelt, mit denen ein hochvariabler 23S rDNA-Bereich amplifiziert werden konnte. Die Nested Specifically Amplified Polymorphic DNA (nSAPD)-PCR wurde in der vorliegenden Arbeit zur Art- und Stamm-Differenzierung pro- und eukaryotischer Organismen angewandt. Es wurden vor allem weinrelevante Milchsäurebakterien der Gattungen Oenococcus, Lactobacillus, Pediococcus und Leuconostoc und Hefen der Gattungen Dekkera / Brettanomyces und Saccharomyces untersucht. Die Cluster-Analyse der Pediococcus-Typstämme führte zu einer unterschiedlichen Baum-Topologie im Vergleich zum phylogenetischen 23S rDNA-Stammbaum. Die Verwandtschaftsverhältnisse der untersuchten O. oeni-Stämme aus Starterkulturen konnten in Bezug auf eine frühere Cluster-Analyse reproduziert werden. Die Untersuchung von 40 B. bruxellensis-Stämmen aus rheinhessischen Weinproben zeigte eine Gruppierung der Stämme gemäß dem Ort der Probennahme. Beim Vergleich der Verwandtschaftsverhältnisse von Stämmen der Arten P. parvulus und B. bruxellensis, die aus denselben Weinproben isoliert wurden, konnte eine hohe Übereinstimmung der beiden Baum-Topologien beobachtet werden. Anhand der SAPD-PCR Untersuchung von Sekthefen aus Starterkulturen konnten alle Stämme der Art S. cerevisiae zugeordnet werden. Die nSAPD-PCR war darüber hinaus geeignet, um höhere Eukaryoten wie Weinreben zu differenzieren und es konnten die Verwandtschaftsverhältnisse von Mäusen und menschlichen Individuen durch Cluster-Analysen nachvollzogen werden. Mit Hilfe der Sequence Characterized Amplified Region (SCAR)-Technik wurden (n)SAPD-Marker in SCAR-Marker konvertiert. Die neu generierten SCAR-Primer konnten zur simultanen Art-Identifizierung von sieben weinschädlichen Milchsäurebakterien in einer Multiplex PCR erfolgreich eingesetzt werden. Die in dieser Arbeit entwickelten molekularbiologischen Identifizierungsmethoden können zum Beispiel in der mikrobiologischen Qualitätskontrolle Anwendung finden.
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Enterobacteriaceae genomes evolve through mutations, rearrangements and horizontal gene transfer (HGT). The latter evolutionary pathway works through the acquisition DNA (GEI) modules of foreign origin that enhances fitness of the host to a given environment. The genome of E. coli IHE3034, a strain isolated from a case of neonatal meningitis, has recently been sequenced and its subsequent sequence analysis has predicted 18 possible GEIs, of which: 8 have not been previously described, 5 fully meet the pathogenic island definition and at least 10 that seem to be of prophagic origin. In order to study the GEI distribution of our reference strain, we screened for the presence 18 GEIs a panel of 132 strains, representative of E. coli diversity. Also, using an inverse nested PCR approach we identified 9 GEI that can form an extrachromosomal circular intermediate (CI) and their respective attachment sites (att). Further, we set up a qPCR approach that allowed us to determine the excision rates of 5 genomic islands in different growth conditions. Four islands, specific for strains appertaining to the sequence type complex 95 (STC95), have been deleted in order to assess their function in a Dictyostelium discoideum grazing assays. Overall, the distribution data presented here indicate that 16 IHE3034 GEIs are more associated to the STC95 strains. Also the functional and genetic characterization has uncovered that GEI 13, 17 and 19 are involved in the resistance to phagocitation by Dictyostelium d thus suggesting a possible role in the adaptation of the pathogen during certain stages of infection.
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Dealing with latent constructs (loaded by reflective and congeneric measures) cross-culturally compared means studying how these unobserved variables vary, and/or covary each other, after controlling for possibly disturbing cultural forces. This yields to the so-called ‘measurement invariance’ matter that refers to the extent to which data collected by the same multi-item measurement instrument (i.e., self-reported questionnaire of items underlying common latent constructs) are comparable across different cultural environments. As a matter of fact, it would be unthinkable exploring latent variables heterogeneity (e.g., latent means; latent levels of deviations from the means (i.e., latent variances), latent levels of shared variation from the respective means (i.e., latent covariances), levels of magnitude of structural path coefficients with regard to causal relations among latent variables) across different populations without controlling for cultural bias in the underlying measures. Furthermore, it would be unrealistic to assess this latter correction without using a framework that is able to take into account all these potential cultural biases across populations simultaneously. Since the real world ‘acts’ in a simultaneous way as well. As a consequence, I, as researcher, may want to control for cultural forces hypothesizing they are all acting at the same time throughout groups of comparison and therefore examining if they are inflating or suppressing my new estimations with hierarchical nested constraints on the original estimated parameters. Multi Sample Structural Equation Modeling-based Confirmatory Factor Analysis (MS-SEM-based CFA) still represents a dominant and flexible statistical framework to work out this potential cultural bias in a simultaneous way. With this dissertation I wanted to make an attempt to introduce new viewpoints on measurement invariance handled under covariance-based SEM framework by means of a consumer behavior modeling application on functional food choices.
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Superconduttori bulk in MgB2, ottenuti con tecnologia Mg-RLI brevettata da Edison Spa, sono stati oggetto di un'approfondita analisi in termini di forze di levitazione. Questo studio è stato preliminare per la progettazione di un innovativo sistema di levitazione lineare. I risultati ottenuti sperimentalmente sono stati validati attraverso modelli numerici sviluppati ad hoc. I campioni oggetto dello studio sono tre bulk in MgB2 rappresentativi delle tipiche forme usate nelle applicazioni reali: un disco, un cilindro, una piastra. I bulk sono stati misurati con un sistema di misura per le forze di levitazione realizzato a tale scopo. Un protocollo sperimentale è stato seguito per la caratterizzazione di base, sia in condizioni Field Cooling sia Zero Field Cooling, al quale sono state affiancate prove specifiche come la possibilità di mantenere inalterate le proprietà superconduttive attraverso la giunzione di più campioni con la tecnologia Mg-RLI. Un modello numerico è stato sviluppato per convalidare i risultati sperimentali e per studiare l'elettrodinamica della levitazione. Diverse configurazioni di rotori magnetici sono state accoppiate con un cilindro in MgB2 con lo scopo di valutare la soluzione ottimale; questo tema è stato apporofondito attraverso lo sviluppo di un software di simulazione che può tenere conto sia del numero di magneti sia della presenza di anelli in materiale magneti intercalati fra di essi. Studi analoghi sono stati portati avanti su una piastra di MgB2 per simulare il comportamento di una geometria piana. Un sistema di raffreddamento innovativo basato sull'azoto solido è stato studiato per poterlo accoppiare con un sistema di levitazione. Il criostato progettato è costituito da due dewar, uno dentro l'altro; quello interno ha lo scopo di raffreddare l'MgB2 mentre quello esterno di limitare delle perdite verso l'esterno. Il criopattino così ottenuto è accoppiato in condizioni FC ad una rotaia formata da magneti permanenti in NdFeB.
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Changepoint analysis is a well established area of statistical research, but in the context of spatio-temporal point processes it is as yet relatively unexplored. Some substantial differences with regard to standard changepoint analysis have to be taken into account: firstly, at every time point the datum is an irregular pattern of points; secondly, in real situations issues of spatial dependence between points and temporal dependence within time segments raise. Our motivating example consists of data concerning the monitoring and recovery of radioactive particles from Sandside beach, North of Scotland; there have been two major changes in the equipment used to detect the particles, representing known potential changepoints in the number of retrieved particles. In addition, offshore particle retrieval campaigns are believed may reduce the particle intensity onshore with an unknown temporal lag; in this latter case, the problem concerns multiple unknown changepoints. We therefore propose a Bayesian approach for detecting multiple changepoints in the intensity function of a spatio-temporal point process, allowing for spatial and temporal dependence within segments. We use Log-Gaussian Cox Processes, a very flexible class of models suitable for environmental applications that can be implemented using integrated nested Laplace approximation (INLA), a computationally efficient alternative to Monte Carlo Markov Chain methods for approximating the posterior distribution of the parameters. Once the posterior curve is obtained, we propose a few methods for detecting significant change points. We present a simulation study, which consists in generating spatio-temporal point pattern series under several scenarios; the performance of the methods is assessed in terms of type I and II errors, detected changepoint locations and accuracy of the segment intensity estimates. We finally apply the above methods to the motivating dataset and find good and sensible results about the presence and quality of changes in the process.
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The aim of the work was to explore the practical applicability of molecular dynamics at different length and time scales. From nanoparticles system over colloids and polymers to biological systems like membranes and finally living cells, a broad range of materials was considered from a theoretical standpoint. In this dissertation five chemistry-related problem are addressed by means of theoretical and computational methods. The main results can be outlined as follows. (1) A systematic study of the effect of the concentration, chain length, and charge of surfactants on fullerene aggregation is presented. The long-discussed problem of the location of C60 in micelles was addressed and fullerenes were found in the hydrophobic region of the micelles. (2) The interactions between graphene sheet of increasing size and phospholipid membrane are quantitatively investigated. (3) A model was proposed to study structure, stability, and dynamics of MoS2, a material well-known for its tribological properties. The telescopic movement of nested nanotubes and the sliding of MoS2 layers is simulated. (4) A mathematical model to gain understaning of the coupled diffusion-swelling process in poly(lactic-co-glycolic acid), PLGA, was proposed. (5) A soft matter cell model is developed to explore the interaction of living cell with artificial surfaces. The effect of the surface properties on the adhesion dynamics of cells are discussed.
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In questo elaborato andremo a descrivere, sia a livello strutturale che implementativo, il progetto sperimentale da noi ideato volto alla creazione di un laboratorio virtuale di testing. Lo scopo principale del laboratorio è appunto quello di delocalizzare la fase preliminare di testing di un'applicazione; nel nostro caso specifico siamo partiti dallo scenario riguardante la rete ferroviaria ed abbiamo preso in esame il software utilizzato per la gestione del traffico. Il vincolo principale che grava su questo progetto è che l'applicazione da collaudare non deve minimamente essere modificata, e ciò significa che occorre creare intorno ad essa un ambiente di testing conforme alle caratteristiche in cui il software si aspetta di operare. Ed è qui che entra in gioco la virtualizzazione.
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I investigated the systematics, phylogeny and biogeographical history of Juncaginaceae, a small family of the early-diverging monocot order Alismatales which comprises about 30 species of annual and perennial herbs. A wide range of methods from classical taxonomy to molecular systematic and biogeographic approaches was used. rnrnIn Chapter 1, a phylogenetic analysis of the family and members of Alismatales was conducted to clarify the circumscription of Juncaginaceae and intrafamilial relationships. For the first time, all accepted genera and those associated with the family in the past were analysed together. Phylogenetic analysis of three molecular markers (rbcL, matK, and atpA) showed that Juncaginaceae are not monophyletic. As a consequence the family is re-circumscribed to exclude Maundia which is pro-posed to belong to a separate family Maundiaceae, reducing Juncaginaceae to include Tetroncium, Cycnogeton and Triglochin. Tetroncium is weakly supported as sister to the rest of the family. The reinstated Cycnogeton (formerly included in Triglochin) is highly supported as sister to Triglochin s.str. Lilaea is nested within Triglochin s. str. and highly supported as sister to the T. bulbosa complex. The results of the molecular analysis are discussed in combination with morphological characters, a key to the genera of the family is given, and several new combinations are made.rnrnIn Chapter 2, phylogenetic relationships in Triglochin were investigated. A species-level phylogeny was constructed based on molecular data obtained from nuclear (ITS, internal transcribed spacer) and chloroplast sequence data (psbA-trnH, matK). Based on the phylogeny of the group, divergence times were estimated and ancestral distribution areas reconstructed. The monophyly of Triglochin is confirmed and relationships between the major lineages of the genus were resolved. A clade comprising the Mediterranean/African T. bulbosa complex and the American T. scilloides (= Lilaea s.) is sister to the rest of the genus which contains two main clades. In the first, the widespread T. striata is sister to a clade comprising annual Triglochin species from Australia. The second clade comprises T. palustris as sister to the T. maritima complex, of which the latter is further divided into a Eurasian and an American subclade. Diversification in Triglochin began in the Miocene or Oligocene, and most disjunctions in Triglochin were dated to the Miocene. Taxonomic diversity in some clades is strongly linked to habitat shifts and can not be observed in old but ecologically invariable lineages such as the non-monophyletic T. maritima.rnrnChapter 3 is a collaborative revision of the Triglochin bulbosa complex, a monophyletic group from the Mediterranean region and Africa. One new species, Triglochin buchenaui, and two new subspecies, T. bulbosa subsp. calcicola and subsp. quarcicola, from South Africa were described. Furthermore, two taxa were elevated to species rank and two reinstated. Altogether, seven species and four subspecies are recognised. An identification key, detailed descriptions and accounts of the ecology and distribution of the taxa are provided. An IUCN conservation status is proposed for each taxon.rnrnChapter 4 deals with the monotypic Tetroncium from southern South America. Tetroncium magellanicum is the only dioecious species in the family. The taxonomic history of the species is described, type material is traced, and a lectotype for the name is designated. Based on an extensive study of herbarium specimens and literature, a detailed description of the species and notes on its ecology and conservation status are provided. A detailed map showing the known distribution area of T. magellanicum is presented. rnrnIn Chapter 5, the flower structure of the rare Australian endemic Maundia triglochinoides (Maundiaceae, see Chapter 1) was studied in a collaborative project. As the morphology of Maundia is poorly known and some characters were described differently in the literature, inflorescences, flowers and fruits were studied using serial mictrotome sections and scanning electron microscopy. The phylogenetic placement, affinities to other taxa, and the evolution of certain characters are discussed. As Maundia exhibits a mosaic of characters of other families of tepaloid core Alismatales, its segregation as a separate family seems plausible.
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Hefen der Gattung Saccharomyces und Milchsäurebakterien sind bei der Weinbereitung von besonderer Bedeutung. Neben der alkoholischen Gärung sind Hefen an der Ausbildung von Aromastoffen beteiligt. Milchsäurebakterien spielen eine Rolle beim biologischen Säureabbau (malolaktische Fermentation), können jedoch aufgrund ihrer Stoffwechseleigenschaft weitere Aromamodifikationen bewirken. Die Zusammensetzung der mikrobiellen Flora zu verschiedenen Zeitpunkten der Weinbereitung hat einen direkten Einfluss auf die Qualität der Weine, welche sich sowohl positiv als auch negativ verändern kann. Daher ist die zuverlässige Identifizierung und Differenzierung verschiedener Mikroorganismen auf Art- aber auch Stamm-Ebene während der Vinifikation von Bedeutung.rnDer erste Teil dieser Arbeit beschäftigte sich mit der Differenzierung von Hefearten der Gattung Saccharomyces, welche mit Hilfe konventioneller Methoden nicht eindeutig identifiziert werden können. Unter Verwendung des DNA-Fingerprintverfahrens Specifically Amplified Polymorphic DNA (SAPD)-PCR sowie der Matrix-Assisted-Laser-Desorption/Ionization-Time-Of-Flight-Mass-Spectrometry (MALDI-TOF-MS) war eine Differenzierung dieser taxonomisch sehr nah verwandten Arten möglich. Weiterhin konnten interspezifische Hybridstämme detektiert werden. In diesem Zusammenhang wurde der Hybridcharakter des Stammes NCYC 3739 (S. cerevisiae x kudriavzevii) entdeckt. Um die Elternspezies eines Hybridstamms zuverlässig zu bestimmen, sind weiterführende Genanalysen notwendig. Hierzu konnte eine Restriktionsfragmentlängenpolymorphismus (RFLP)-Analyse verschiedener genetischer Marker erfolgreich herangezogen werden.rnIm Rahmen dieser Arbeit wurde weiterhin ein Schnellidentifizierungssystem zum Nachweis weinrelevanter Milchsäurebakterien entwickelt. Mit Hilfe der Sequence Characterized Amplified Region (SCAR)-Technik konnten artspezifische Primer generiert werden, welche auf der Grundlage charakteristischer Fragmente der SAPD-PCR abgeleitet wurden. Durch die Anwendung dieser Primer in einer Multiplex-PCR-Reaktion war die Detektion verschiedener, einerseits häufig in Wein vorkommender und andererseits potentiell an der Ausbildung von Weinfehlern beteiligter Milchsäurebakterien-Arten möglich. Die ermittelte Nachweisgrenze dieser Methode lag mit 10^4 - 10^5 Zellen/ml im Bereich der Zelltiter, die in Most und Wein anzutreffen sind. Anhand der Untersuchung verschiedener Weinproben von Winzern in Rheinhessen wurde die Praxistauglichkeit dieser Methode demonstriert. rnUm die gesamten Milchsäurebakterien-Population im Verlauf der Weinbereitung zu kontrollieren, kann die Denaturierende Gradienten-Gelelektrophorese herangezogen werden. Hierzu wurden in dieser Arbeit Primer zur Amplifikation eines Teilbereichs des rpoB-Gens abgeleitet, da dieses Gen eine Alternative zur 16S rDNA darstellt. Die DNA-Region erwies sich als geeignet, um zahlreiche weinrelevante Milchsäurebakterien-Arten zu differenzieren. In einigen ersten Versuchen konnte gezeigt werden, dass diese Methode für eine praktische Anwendung in Frage kommt.rnOenococcus oeni ist das wichtigste Milchsäurebakterien während der malolaktischen Fermentation und wird häufig in Form kommerzieller Starterkulturen eingesetzt. Da verschiedene Stämme unterschiedliche Eigenschaften aufweisen können, ist es von Bedeutung, die Identität eines bestimmten Stammes zweifelsfrei feststellen zu können. Anhand der Analyse verschiedener O. oeni-Stämme aus unterschiedlichen Weinbaugebieten konnte gezeigt werden, dass sowohl die nested SAPD-PCR als auch die MALDI-TOF-MS genügend Sensitivität aufweisen, um eine Unterscheidung auf Stamm-Ebene zu ermöglichen, wobei die mittels nSAPD-PCR ermittelten Distanzen der Stämme zueinander mit deren geographischer Herkunft korrelierte.rnDie in der vorliegenden Arbeit entwickelten Methoden können dazu beitragen, den Prozess der Weinherstellung besser zu kontrollieren und so eine hohe Qualität des Endproduktes zu gewährleisten.rn
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The columnar growth habit of apple is interesting from an economic point of view as the pillar-like trees require little space and labor. Genetic engineering could be used to speed up breeding for columnar trees with high fruit quality and disease resistance. For this purpose, this study dealt with the molecular causes of this interesting phenotype. The original bud sport mutation that led to the columnar growth habit was found to be a novel nested insertion of a Gypsy-44 LTR retrotransposon on chromosome 10 at 18.79 Mb. This subsequently causes tissue-specific differential expression of nearby downstream genes, particularly of a gene encoding a 2OG-Fe(II) oxygenase of unknown function (dmr6-like) that is strongly upregulated in developing aerial tissues of columnar trees. The tissue-specificity of the differential expression suggests involvement of cis-regulatory regions and/or tissue-specific epigenetic markers whose influence on gene expression is altered due to the retrotransposon insertion. This eventually leads to changes in genes associated with stress and defense reactions, cell wall and cell membrane metabolism as well as phytohormone biosynthesis and signaling, which act together to cause the typical phenotype characteristics of columnar trees such as short internodes and the absence of long lateral branches. In future, transformation experiments introducing Gypsy-44 into non-columnar varieties or excising Gypsy-44 from columnar varieties would provide proof for our hypotheses. However, since site-specific transformation of a nested retrotransposon is a (too) ambitious objective, silencing of the Gypsy-44 transcripts or the nearby genes would also provide helpful clues.