A cana-de-açúcar é uma das principais culturas do sistema agrícola brasileiro, e apresenta-se atualmente em plena expansão. Porém o uso do solo e a implementação de diferentes tecnologias de manejo têm originado alterações no equilíbrio ambiental, onde importantes interações microbianas ocorrem de forma essencial para o desenvolvimento vegetal. Dentre a vasta diversidade de microrganismos do solo, destacam-se os fungos micorrízicos, organismos intimamente associados as raízes das plantas, auxiliando a mesma, dentre outras formas, na obtenção de água e nutrientes. Estes fungos, no entanto, interagem também com outros organismos do solo, como por exemplo, com a comunidade bacteriana presente neste ambiente. Desta forma, o presente trabalho buscou estudar a dinâmica de interação entre cana-de-açúcar e o fungo micorrízico arbuscular (FMA) G.clarum em solos com diferentes composições da comunidade bacteriana. A metodologia utilizada foi a \'diluição para extinção\', onde diluições seriadas (10-1; 10-3; 10-6 e 10-9) de um solo natural foram usadas para inocular o solo estéril. Sobre esta base, foi monitorada pelo período de 60 dias, a colonização da planta pelo FMA e a estruturação das comunidades bacterianas. Como resultado, foi observada uma maior colonização das raízes de cana-de-açúcar para os tratamentos inoculada com menores diluições da comunidade original (solo natural e diluições 10-1 e 10-3), sendo da mesma forma observada uma distinção entre as comunidades bacterianas destes tratamentos para os demais. Estabelecendo correlações entre os grupos microbianos e as taxas de colonização micorrízica, foi possível nomear, com base no sequenciamento massivo da região V6 do gene ribossomal 16S DNAr, a alteração conjunta da micorrização com mudanças nos grupos de Actinobacteria,Bacteriodetes,Firmicutes,Proteobacteria,Verrucomicrobiae Acidobacteria. Concluindo, este trabalho demonstra a dependência que um processo importante, como a micorrização, possui da comunidade bacteriana do solo, e indica que em áreas degradadas, com menores níveis de diversidade bacteriana, tal processo pode ocorrer com menor eficiência. / Sugarcane is an important Brazilian agricultural system crop and presents currently booming. Nevertheless, land use, and implementation of different management technologies have originated changes in environmental balance, where important microbial interactions occur as essential for plant development. Among the wide diversity of soil microorganisms, the mycorrhizal fungi is highilighted as organisms closely associated with plant roots, helping plants, in any way, to obtain water and nutrients. These fungi however, also interact with other soil organisms, such as for example, bacterial community in these environments. Thus, the present work aimed to study the dynamics of interaction between sugarcane and arbuscularmycorrhizal fungi (AMF) Glomusclarum in soils with different compositions of the bacterial community. The methodology used was \"dilution to extinction\", where serial dilutions (10-1, 10-3, 10-6 and 10-9) of a natural soil were used to inoculate a sterile soil. On this basis, were monitored along a period of 60 days, plant colonization by AMF, and structure of bacterial communities. As a result, we observed a higher colonization of roots of cane sugar for treatments inoculated with lower dilutions of the original community (natural soil and dilutions 10-1 and 10-3), and likewise observed a distinction between these bacterial communities treatments to others. Establishing correlations between microbial groups with observed rates of colonization, it was possible to name, based on the massive sequencing of the region V6 ribosomal gene 16S rDNA, the joint amendment of mycorrhiza with changes in groups of Actinobacteria; Bacteriodetes; Firmicutes, Proteobacteria; Verrucomicrobia and Acidobacteria. In conclusion, this work demonstrates the dependence of an important process, as the AMF, has tosoil bacterial community, and indicates that degraded areas, with lower levels of bacterial diversity, such a process can occur with lower efficiency.

Traditional excess Gibbs energy models in terms of temperature, pressure, and concentration become progressively less effective in describing the thermodynamics of aqueous solutions at temperatures above 300 ¢ªC, and are totally inadequate in the critical region of water. This deficiency is due to the strong ion association and the large property fluctuations (such as density) with small variations in pressure, temperature, and solute concentration around the critical point of water. In this work, a speciation-based model has been developed to describe the thermodynamic properties of aqueous sodium chloride solutions in the critical region of water. The anomalous fluctuation problem is avoided by adopting a residual Helmholtz energy approach in terms of temperature, density, and solute concentration. Partial ion dissociation is accounted for by including an isochoric equilibrium constant equation and a mean spherical approximation in the present model. The present model includes such classical interactions or effects as hard-sphere interactions, dipole-dipole interactions, ion dissociation effects, long-range ion-ion interactions, and a non-classical perturbation term. The related parameters that account for these effects were regressed to fit the measured values in the critical region of water. Densities, compressibility factors, apparent molar volumes, heats of dilution, and apparent isobaric molar heat capacities were used to test the validity of the model. The predicted values in this work agree well with the literature data over a wide range of temperatures (350 to 400 ¢ªC), pressures (17.5 to 40 MPa), and sodium chloride concentrations (0 to 5 mol/kg). Comparisons with other models are also included in this work. This model can be used to predict speciation, solute dissociation reaction, and many other comprehensive properties in aqueous sodium chloride solutions at near-critical conditions.

La mise au point d’une méthode d’analyse par UPLC-MS/MS et dilution isotopique nous a permis d’identifier pour la première fois dans un moût le S-3-(hexan-1-ol)-<gamma>-glutamyl-cystéine (<gamma>GluCys-3MH). Suite à cette découverte, l’étude des interconversions entre les glutathionylés, dipeptides et cystéinylés S-conjugués au 3-mercaptohexan-1-ol (3MH) ou à la 4-mercapto-4-méthyl-pentan-2-one (4MMP), a permis de mettre en évidence deux nouvelles formes de précurseurs. Le suivi de l’évolution de ces différents composés au cours de fermentations alcooliques à l’échelle laboratoire a permis de clarifier leur rôle de précurseurs et d’établir les éventuels mécanismes d’interconversion. Par ailleurs, à travers plusieurs expérimentations viticoles et œnologiques conduites à l’échelle pilote en Languedoc et Val de Loire pendant trois années consécutives, des éléments nouveaux ont pu être apportés quant à l’impact de la maturation du raisin et son hétérogénéité, ainsi qu’à l’importance des opérations pré-fermentaires comme la macération pelliculaire ou la stabulation sur bourbes. / The development of a method using UPLC-MS/MS and stable isotope dilution assay allowed us to identify for the first time the S-3-(hexan-1-ol)-<gamma>-glutamyl-cysteine (<gamma>GluCys-3MH) in musts. Following this discovery, the study of interconversions between glutathione, dipeptides and cysteine S-conjugates to 3-mercaptohexan-1-ol (3MH) or 4-mercapto-4-methyl-pentan-2-one (4MMP) highlighted two new forms of precursors. The evolution monitoring of these compounds during alcoholic fermentations at laboratory scale allowed us to clarify their role as precursors and to establish the possible interconversion mechanisms. In addition, through several viticultural and oenological experiments carried out at pilot scale in Languedoc and Val de Loire during three consecutive years, new elements could be … about the impact of grape ripening and its heterogeneity, as well as the importance of prefermentative processes, such as skin maceration and must conservation on lees.

gamma-Lactones are found in a wide variety of food and beverage products, in particular grapes and wine. This thesis details the work completed on some gamma-lactones in wine: their synthetic preparation, development of quantification methodologies and sensory studies. Chapter 1 outlines the history of the Australian wine industry from the arrival of the first vines on the First Fleet in 1788 with Captain Arthur Philip. This chapter provides: an overview of Australia’s position in the world of grape and wine production; an analysis of the export arm of the industry; and a look at the different wine producing regions around the country. The latter part of the chapter focuses on the different volatile compounds found in wine. Part A: Chapter 2 provides an overview on the history of barrel manufacture and the use of oak wood in cooperage, with an emphasis on oak’s well known ability to impart desirable characteristics to wine through the extraction of volatile aroma compounds. This chapter provides a summary of these odorants with a particular emphasis on the oak lactones. Previous sensory studies and synthetic work are discussed. Of great importance to this work are the recent advancements in 1,2-dioxine chemistry, highlighted in this chapter. Chapter 3 details the synthetic work completed for the preparation of all four possible oak lactone stereoisomers. A suitably substituted racemic 1,2-dioxine featured as the common intermediate and enabled preparation of the gamma-lactone moiety upon reaction with a chiral malonate diester and separation of the diastereomers by column chromatography. A key step involved the decarboxylation of the ester cleaved gamma-lactone diastereomers, which could be directed to give either the cis- or trans-products. Standard chemical transformations were then utilised to produce the desired stereoisomers of oak lactone. Chapter 4 describes the results from the sensory studies that were completed on the synthetic oak lactone samples. Odour detection thresholds were measured in both a white and a red wine. The thresholds in the former medium were calculated to be 24 ug/L, 172 ug/L, 132 ug/L and 305 ug/L, while in the latter medium the thresholds were calculated to be 57 ug/L, 380 ug/L, 175 ug/L and 285 ug/L, for (4S,5S)-cis-, (4S,5R)-trans-, (4R,5R)-cis- and (4R,5S)-trans-oak lactone, respectively. Difference testings were completed on the pairs of enantiomers and also on mixtures of the nature-identical isomers: between the cis-enantiomers a significant difference was found at the 99% confidence level, while between the trans-enantiomers and also the mixtures of cis- and trans-isomers little difference was observed. Chapter 5 contains the experimental procedures for Part A. Part B: Chapter 6 discusses the sensory properties of some gamma- and delta-lactones, with the focus on a series of five-alkyl substituted gamma-lactones: gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone. Topics covered in this chapter include chirality, biosynthetic pathways and quantification results in wine from previous studies for these gamma-lactones. Chapter 7 concerns the method development for the quantification of gamma-lactones in wine using a stable isotope dilution assay (SIDA). Deuterated analogues were prepared from commercially available racemic gamma-lactones for use as internal standards. Initially a head space solid-phase microextraction (HS SPME) method was developed using d5-standards; however, analysis of bottled wine samples revealed the presence of co-eluting compounds that contained several of the selected ions. Thus an alternative method was developed using d7-standards, with a specific focus on sample clean-up, via solid-phase extraction (SPE). Using this procedure, 44 white and 120 red wines were analysed for their gamma-lactone content. The lactones were found to be significantly more common in the red wines, with gamma-nonalactone the most abundant lactone in this series. Chapter 8 deals with the extension of the SIDA method, as developed in Chapter 7, for use with a chiral gas chromatography column. Optically pure standards were prepared, from either L- or D-glutamic acid, and used to determine the order of elution of the enantiomers. A method was developed for the quantification of the individual enantiomers of gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone. The enantiomeric distribution of gamma-nonalactone was investigated in 34 red wines; the (R)-stereoisomer was found to be dominant with an average of 59%, although there were wines analysed that did contain the (S)-stereoisomer in greater amounts. Chapter 9 describes the results from the sensory studies that were completed on the individual enantiomers of the gamma-lactones. Odour detection thresholds were measured in a red wine. The thresholds were calculated to be 238 ug/L, 285 ug/L, 34 ug/L and 8 ug/L for the (R)-enantiomers, while the thresholds were calculated to be 135 ug/L, 91 ug/L, 47 ug/L and 39 ug/L for the (S)-enantiomers, of gamma-octalactone, gamma-nonalactone, gamma-decalactone and gamma-dodecalactone, respectively. Chapter 10 contains the experimental procedures for Part B. Chapter 11 contains the appendices, followed by the references in Chapter 12.

La mesure du rayonnement cosmologique (CMB pour Cosmic Microwave Background) en est à un point crucial. Les expériences qui le mesurent sont de plus en plus sensibles et précises. Ce manuscrit présente deux instruments dont l'objectif est de mesurer les anisotropies de température de ce rayonnement. Dans une première partie nous présentons le travail effectué sur l'optimisation du refroidissement des détecteurs grâce a une dilution en cycle ouvert de l'3He dans l'4He dans le cadre de l'expérience satellite Planck. Trois types de supports pour l'échangeur à contre-courant permettant d'atteindre 100 mK avec une puissance disponible de 100 nW sont étudiés. Lors des essais, nous avons approfondi la compréhension de phénomènes physiques présents dans une dilution à cycle ouvert. La deuxième partie présente un filtrage original pour atteindre une grande stabilité de température à 100 mK. En réalisant différentes expériences nous démontrons l'efficacité d'un filtre continu à forte capacité calorifique. Ce filtre, en HoY, a été qualifié d'un point de vue spatial afin d'être utilisé pour le satellite Planck. La troisième partie de ce manuscrit est entièrement consacrée à l'expérience Archeops. Dans ce cadre nous avons développé un cryostat spécifique pour la mesure en ballon stratosphérique. Cette expérience nous a permis d'approfondir plusieurs domaines de la mesure du CMB telles que la bolométrie, l'électronique et l'analyse d'un signal complexe. Les données prometteuses du dernier vol devraient contraindre les paramètres cosmologiques.

Användandet av olika incitamentsprogram och aktierelaterade ersättningar i synnerhet har ökat sen 80-talet. Aktierelaterade ersättningsprogram används för att uppmuntra persona-len att aktivt deltaga för att förbättra företagets resultat. Ersättningarna i dessa program be-står antingen av köpotioner, teckningsoptioner, syntetiska optioner eller konvertibler. Sedan den 1 januari 2005 gäller de nya redovisningsreglerna IFRS 2. Dessa regler styr redo-visningen av aktierelaterade ersättningar. IFRS 2 kräver att alla företag noterade på någon börs inom EU kostnadsför dessa ersättningar i resultaträkningen. Innan implementeringen av de nya reglerna räckte det med att ta upp dessa ersättningar i notform. IFRS 2 kräver att dessa regler retroaktivt skall användas för att påvisa dess effekter på 2004 års resultaträk-ning. Anledningen till detta är att potentiella investerare skall ha möjlighet att kunna jämfö-ra resultaträkningar från olika år. Syftet med uppsatsen är att undersöka vilka effekter företagen på den svenska A-listan skul-le få erfara om IFRS 2 var implementerad redan år 2004. Vidare ämnar vi att beskriva hur aktierelaterade ersättningsprogram används och hur detta påverkar företagen. Uppsatsen är genomförd med en kvantitativ ansats och har baserats på sekundärdata från företagens årsrapporter. Vårt urval är det samma som totalpopulationen på den svenska A-listan. De slutsatser som vi kunnat dra i vår uppsats är att majoriteten av de noterade företagen på A-listan använder någon form av aktierelaterade ersättningsprogram. Den mest använda optionstypen är teckningsoptioner. I medel skulle resultatet minskat med 0,89 procent på grund av IFRS 2. Utspädningseffekten som orsakats av aktierelaterade ersättningar var i medel 0,54 procent. Företagen på A-listan använder i huvudsak Black &amp; Scholes-modellen vid värdering av de aktierelaterade ersättningsprogrammen. Vidare indikerar resultatet av vår studie att företag som använder köpoptioner skulle ha haft mest negativ resultatpåver-kan på grund av IFRS 2. En annan intressant slutsats är att större företag tenderar att in-volvera alla anställda i sina aktieoptionsprogram medan mindre bolag föredrar att rikta des-sa aktierelaterade ersättningar endast till chefer och ledning. / The use of incitement programs and share-based programs in particular has increased since the 1980`s. These share-based programs are used to encourage the employees to actively participate in increasing the company’s result. The payment in these share-based compen-sations either is; call options, subscription options, synthetic options or convertibles. From January 1 2005, the new accounting regulation IFRS 2 regarding share-based pay-ments are implemented. The IFRS 2 demands all companies noted on a stock exchange in the European Union to account for the share-based payments and expense these in the in-come statement. Before this implementation, these payments only had to be described in a disclosed form. However for the year 2004, the effects due to the IFRS 2 have to be taken into consideration in the income statement. The reason for this is that potential investors must have the possibility to compare the financial statements between different time peri-ods. The purpose with thesis is to cover what effects the companies’ on the Swedish A-list should have had if the IFRS 2 were implemented already the year 2004. Secondly, the aim is to cover and describe the utilization of share-based programs among these companies and to explain how they are affected. The thesis is conducted through a quantitative approach and based on secondary data from annual reports of the companies’. Our selection is the total population on the Swedish A-list. The conclusions made in our thesis are that the majority of the A-listed companies’ use some kind of share-based programs. The most frequently used option type is the subscrip-tion option. On average, the decrease in result was 0,89 percent due to IFRS 2. On average the dilution effect due to the use of share-based programs decreased the result per share by 0,54 percent. The companies on the A-list use the Black &amp; Scholes formula to valuate the share-based payments. Our study also indicates that the companies using call options should have experienced the greatest result decrease due to the IFRS 2. Another interesting conclusion is that the larger companies in our study are most likely to involve all the em-ployees’ in the share-based programs while the smaller companies prefer to only involve executives and other leading personnel.

Clinical management of esophageal adenocarcinoma (EAC) relies on radiation therapy, yet radioresistance is a pervasive challenge in this disease. The mechanisms of EAC radioresistance remain largely unknown due to a paucity of validated preclinical models. The present studies report on the development of seven primary xenograft models established from patient tumours. These models are used to interrogate the range of radiosensitivities and mechanisms of radioresistance in EAC tumours. We found that radiation enriches the tumour-initiating cell population in two xenograft lines tested. Furthermore, three tested xenograft lines respond to irradiation by upregulating Hedgehog transcripts, a pathway involved in stem cell maintenance and proliferation. Upregulation occurs in autocrine and paracrine patterns simultaneously, suggesting that Hedgehog signalling may have a complex role in the radioresponse of EAC tumours. These findings suggest that inhibiting stem cell pathways in combination with radiotherapy may have an important role in the clinical management of EAC.

<p>Användandet av olika incitamentsprogram och aktierelaterade ersättningar i synnerhet har ökat sen 80-talet. Aktierelaterade ersättningsprogram används för att uppmuntra persona-len att aktivt deltaga för att förbättra företagets resultat. Ersättningarna i dessa program be-står antingen av köpotioner, teckningsoptioner, syntetiska optioner eller konvertibler.</p><p>Sedan den 1 januari 2005 gäller de nya redovisningsreglerna IFRS 2. Dessa regler styr redo-visningen av aktierelaterade ersättningar. IFRS 2 kräver att alla företag noterade på någon börs inom EU kostnadsför dessa ersättningar i resultaträkningen. Innan implementeringen av de nya reglerna räckte det med att ta upp dessa ersättningar i notform. IFRS 2 kräver att dessa regler retroaktivt skall användas för att påvisa dess effekter på 2004 års resultaträk-ning. Anledningen till detta är att potentiella investerare skall ha möjlighet att kunna jämfö-ra resultaträkningar från olika år.</p><p>Syftet med uppsatsen är att undersöka vilka effekter företagen på den svenska A-listan skul-le få erfara om IFRS 2 var implementerad redan år 2004. Vidare ämnar vi att beskriva hur aktierelaterade ersättningsprogram används och hur detta påverkar företagen.</p><p>Uppsatsen är genomförd med en kvantitativ ansats och har baserats på sekundärdata från företagens årsrapporter. Vårt urval är det samma som totalpopulationen på den svenska A-listan.</p><p>De slutsatser som vi kunnat dra i vår uppsats är att majoriteten av de noterade företagen på A-listan använder någon form av aktierelaterade ersättningsprogram. Den mest använda optionstypen är teckningsoptioner. I medel skulle resultatet minskat med 0,89 procent på grund av IFRS 2. Utspädningseffekten som orsakats av aktierelaterade ersättningar var i medel 0,54 procent. Företagen på A-listan använder i huvudsak Black & Scholes-modellen vid värdering av de aktierelaterade ersättningsprogrammen. Vidare indikerar resultatet av vår studie att företag som använder köpoptioner skulle ha haft mest negativ resultatpåver-kan på grund av IFRS 2. En annan intressant slutsats är att större företag tenderar att in-volvera alla anställda i sina aktieoptionsprogram medan mindre bolag föredrar att rikta des-sa aktierelaterade ersättningar endast till chefer och ledning.</p> / <p>The use of incitement programs and share-based programs in particular has increased since the 1980`s. These share-based programs are used to encourage the employees to actively participate in increasing the company’s result. The payment in these share-based compen-sations either is; call options, subscription options, synthetic options or convertibles.</p><p>From January 1 2005, the new accounting regulation IFRS 2 regarding share-based pay-ments are implemented. The IFRS 2 demands all companies noted on a stock exchange in the European Union to account for the share-based payments and expense these in the in-come statement. Before this implementation, these payments only had to be described in a disclosed form. However for the year 2004, the effects due to the IFRS 2 have to be taken into consideration in the income statement. The reason for this is that potential investors must have the possibility to compare the financial statements between different time peri-ods.</p><p>The purpose with thesis is to cover what effects the companies’ on the Swedish A-list should have had if the IFRS 2 were implemented already the year 2004. Secondly, the aim is to cover and describe the utilization of share-based programs among these companies and to explain how they are affected.</p><p>The thesis is conducted through a quantitative approach and based on secondary data from annual reports of the companies’. Our selection is the total population on the Swedish A-list.</p><p>The conclusions made in our thesis are that the majority of the A-listed companies’ use some kind of share-based programs. The most frequently used option type is the subscrip-tion option. On average, the decrease in result was 0,89 percent due to IFRS 2. On average the dilution effect due to the use of share-based programs decreased the result per share by 0,54 percent. The companies on the A-list use the Black & Scholes formula to valuate the share-based payments. Our study also indicates that the companies using call options should have experienced the greatest result decrease due to the IFRS 2. Another interesting conclusion is that the larger companies in our study are most likely to involve all the em-ployees’ in the share-based programs while the smaller companies prefer to only involve executives and other leading personnel.</p>

Es wurde ein Modell zur realistischen Beschreibung der Kühlmittelvermischung innerhalb des Reaktordruckbehälters von Druckwasserreaktoren in den gekoppelten Programmkomplex DYN3D/ATHLET implementiert. Diese Modell basiert auf dem Prinzip der linearen Superposition Dirac-Impuls-ähnlicher Störungen und kann für die Modellierung der Vermischung von Kühlmittel unterschiedlicher Temperatur und/oder unterschiedlicher Borsäurekonzentration eingesetzt werden. Der um das Vermischungsmodell erweiterte Programmkomplex DYN3D/ATHLET wurde für Analyse von Borverdünnungsstörfällen und Frischdampflecks angewandt. Für den Fall "Start der ersten Hauptkühlmittelpumpe bei Vorhandensein eines minderborierten Pfropfens im kalten Strang" zeigten die Ergebnisse der durchgeführten Parameterstudie, dass es selbst bei Annahme des maximal möglichen Pfropfenvolumens nicht zu einer Schädigung des Brennstoffes kommt. Mit den Analysen zu einem generischen Frischdampfleckszenario wurde die Anwendbarkeit des Programmkomplexes DYN3D/ATHLET auf die zweite Störfallklasse, in der die Kühlmittelvermischung eine wichtige Rollen spielt, demonstriert. Im Rahmen der Arbeiten zum Projekt wurde außerdem gezeigt, dass der Einfluss der turbulenten Schwankungen des Geschwindigkeitsfeldes innerhalb des Reaktordruckbehälters auf neutronenkinetische Parameter im Nominalbetrieb und unter Störfallbedingungen nicht zu vernachlässigen ist. A model for the realistic description of the coolant mixing inside the pressure vessel of pressurized water reactors was implemented into the coupled code complex DYN3D/ATHLET. This model is based on the linear superposition Dirac-pulse-like perturbations. The model can be applied to the mixing of coolant of different temperature and/or boron concentration. The coupled code complex DYN3D/ATHLET with the newly implemented model was applied to the analysis of boron dilution and steam line break accidents. The results of a parameter study for the case "Start-up of the first main coolant pump with a slug of lower borated water in the cold leg" have shown, that even under the conditions of the maximum slug volume there is no fuel damage. The applicability to the second class of accidents, where the coolant mixing has to be considered, was demonstrated by the analysis of a generic main steam line break scenario. Further it was shown, that the influence of turbulent fluctuations of the velocity inside the reactor pressure vessel during nominal and accident conditions on neutron-kinetic parameters cannot be neglected.

The goal of the work described in this report was the experimental investigation of the mixing of coolant with different quality (temperature, boron concentration) in nuclear reactors on the way from the cold leg through the downcomer and lower plenum to the core inlet in a systematic way. The obtained data were used for the clarification of the mixing mechanisms and form a data basis for the validation of computational fluid dynamics (CFD) codes. For these purposes, experiments on slug mixing have been performed at two test facilities, modelling different reactor types in scale 1:5, the Rossendorf and Vattenfall test facilities. The corresponding accident scenario is the start-up of first main coolant pump (MCP) after formation of a slug of lower borated water during the reflux-condenser mode phase of a small break loss of coolant accident (LOCA). The matrices for the experiments were elaborated on the basis of the key phenomena, being responsible for the coolant mixing during pump start-up. Slug mixing tests have also been performed at the VVER-1000 facility of EDO Gidropress to meet the specifics of this reactor type. The mixing of slugs of water of different quality is also very important for pre-stressed thermal shock (PTS) situations. In emergency core cooling (ECC) situations after a LOCA, cold ECC water is injected into the hot water in the cold leg and downcomer. Due to the large temperature differences, thermal shocks are induced at the reactor pressure vessel (RPV) wall. Temperature distributions near the wall and temperature gradients in time are important to be known for the assessment of thermal stresses. One of the important phenomena in connection with PTS is thermal stratification, a flow condition with a vertical temperature profile in a horizontal pipe. Due to the fluctuating character of the flow, this may cause thermal fatigue in the pipe. Besides of thermal fatigue, a single thermal shock can also be relevant for structural integrity, if it is large enough, especially in the case, that the brittle fracture temperature of the RPV material is reduced due to radiation embrittlement. Therefore, additional to the investigations of slug mixing during re-start of coolant circulation, the mixing of slugs or streams of water with higher density with the ambient fluid in the RPV was investigated. The aim of these investigations was to study the process of turbulent mixing under the influence of buoyancy forces caused by the temperature differences. Heat transfer to the wall and thermal conductivity in the wall material have not been considered. Experiments on density driven mixing were carried out at the Rossendorf and the Fortum PTS facilities.