The rapid expansion of Great Cormorant populations during the second part of the 20th century has caused many conflicts, mostly with fisheries. Cormorants are often considered as important reason for depleted fish stocks, although evidences are often insufficient. This study of the Great Cormorant diet took place in the largest Lithuanian colony near Juodkrantė. Important for the impact evaluation cormorant nutrition aspects, including diet composition, its temporal variation and feeding selectivity, were determined. The reliability of pellet analysis for quantitative dietary assessments was evaluated for the first time using a stable isotope mixing model. Great Cormorant impact on spatial fish distribution was also assessed for the first time. Long-term fish community monitoring data were used for Cormorant impact assessment in the Curonian Lagoon. The results of our study are important for providing improved assessments of the long-term effects of Cormorants on fish communities in large, complex, highly productive aquatic systems. The practical significance of this study is its evaluation of competition between cormorants and commercial fishermen, which enables to substantiate the need to regulate cormorant population. Assessments of Cormorant impact on invasive Round Goby populations is also important. / XX amžiaus antroje pusėje didžiųjų kormoranų populiacijos Europoje staigus augimas sukėlė eilę konfliktų, daugiausia su žvejais ir žuvų augintojais. Kormoranai dažnai kaltinami dėl mažėjančių žuvų išteklių, tačiau moksliniais tyrimais pagrįstų įrodymų dažnai trūksta. Šiame tyrime buvo tiriama didžiųjų kormoranų mityba didžiausioje Lietuvoje Juodkrantės kolonijoje. Darbe buvo nustatyti svarbūs kormoranų poveikio vertinimui mitybos aspektai – raciono sudėtis ir jos kitimas laike, mitybos selektyvumas. Pirmą kartą buvo įvertintas atrajų analizės metodo patikimumas raciono sudėties kiekybiniam vertinimui, naudojant stabiliųjų izotopų sudėties analizės metodą. Taip pat pirmą kartą buvo vertinamas didžiųjų kormoranų poveikis žuvų populiacijoms erdvėje. Remiantis daugiamečio monitoringo duomenimis, buvo įvertintas kormoranų poveikis žuvų populiacijoms Kuršių mariose. Šio tyrimo rezultatai leidžia geriau įvertinti didžiųjų kormoranų ilgalaikį poveikį žuvų bendrijoms didelėse sudėtingose aukšto produktyvumo vandens sistemose. Praktinę vertę šiame darbe turi kormoranų ir žvejų verslininkų tiesioginės ir netiesioginės konkurencijos įvertinimas, leidžiantis pagrįsti kormoranų populiacijos reguliavimo priemonių tikslingumą. Svarbus praktiškai yra ir kormoranų poveikio invazinio juodažiočio grundalo populiacijai įvertinimas.

Ces travaux de thèse ont permis de développer une voie d’accès à des systèmes polycycliques complexes contenant un cyclooctatétraène par réactions en cascade palladocatalysées à partir de substrats de départ originaux. Le mécanisme de formation de ces composés est tout à fait particulier. Une étude mécanistique approfondie, corroborée notamment par des calculs DFT, a mis en avant une étape de réaction inédite : une électrocyclisation conrotatoire 8pi d’un système triènyne formant ainsi un cyclooctadiènallène palladé. Cette méthodologie a permis de synthétiser de nombreux cyclooctatétraènes présentant une large diversité moléculaire. Les différents substituants du cyclooctatétraène ont pu être variés ainsi que la taille des cycles fusionnés à ce cyclooctatétraène. / This thesis work focused on the development of a new synthetic pathway leading to complex polycyclic molecules containing a cyclooctatetraene moiety via palladium-catalyzed cascade reactions from original starting substrates. The mechanism of formation of these compounds is very special. A thorough mechanistic study, supported in particular by DFT calculations, highlighted an unprecedented reaction step: an conrotatory 8pi electrocyclization of a trienyne system forming a palladiated cyclooctadienallene. This methodology allowed the synthesis of many cyclooctatetraenes showing a broad molecular diversity. The different substituents bearing by the cyclooctatetraene core were varied as well as the size of the fused rings to the cyclooctatetraene.

Great cormorant (Phalacrocorax carbo) populations have experienced a rapid growth in Europe since the 1980s, resulting in conflicts with fisheries over local fish resources. The 8-fjords area is a marine protected area on the Swedish west coast, where long term overfishing has led to a collapse of several local demersal fish stocks. Subsequently, fishing regulations have been implemented to protect and re-establish the stocks of cod- and flatfish species, at the same time as cormorants have increased largely in numbers. The increased predation pressure has raised concerns about the recovery of local fish stocks, although knowledge about cormorant feeding habits are lacking. Here, cormorant prey choice in two subareas of the 8-fjords area is investigated, using morphological identification of prey remains in regurgitated pellets. An estimated 15 077 fishes were identified from a total of 480 pellets. The most important prey families based on relative abundance were flatfish (Pleuronectidae 48%), gobies (Gobiidae 21%) and codfish (Gadidae 13%). Pairwise ANOSIM analyses showed extremely small differences in diet composition between sites (p≤0.003, R<0.08). In comparison to available monitoring fishery data, the diet did not correspond to prey abundance. Estimated fish sizes of a subsample of flat- and codfish showed that juveniles seemed to be preferred. Pellet analysis provided limited information about consumed species and should be combined with other methods for more detailed assessments of cormorant prey choice in the 8-fjords area.

Workers involved in hydraulic fracking processes are exposed to various types of chemicals and dusts in their workplaces, such as proppants, which hold open the fissures created in the fracking process. Recently, ceramic proppants have been developed that may be less hazardous to workers than traditional proppants. Pulmonary function testing of workers producing ceramic proppant was used to assess the potential inhalation hazards of ceramic proppant. Male workers (n = 100) from a producer of ceramic proppant were evaluated with pulmonary function test data collected and evaluated using The American Thoracic Society (ATS) acceptability criteria. A comparison group was selected from the Third National Health and Nutrition Examination Survey (NHANES III) spirometry laboratory subset. No pulmonary function deficits were found in the worker group in comparison to the NHANES III population. Multiple linear regression analysis showed that the mean FEV1 and FVC values in workers were 0.11 and 0.08 liters respectively, and were greater as compared to the NHANES III population. Curiously, an FEV1/FVC ratio of less than 0.8, when compared to the NHANES III group, produced an odds ratio of 0.44 in worker group, indicating less risk of preclinical pulmonary dysfunction. Overall, exposure to ceramic proppant was not found to produce an adverse impact on pulmonary function in workers engaged in the manufacture of ceramic proppant.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22488号 / 農博第2392号 / 新制||農||1076(附属図書館) / 学位論文||R2||N5268(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 藤原 正幸, 教授 村上 章, 准教授 宇波 耕一 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Yes / Bifractional transformations which lead to quantities that interpolate between other known quantities are considered. They do not form a group, and groupoids are used to describe their mathematical structure. Bifractional coherent states and bifractional Wigner functions are also defined. The properties of the bifractional coherent states are studied. The bifractional Wigner functions are used in generalizations of the Moyal star formalism. A generalized Berezin formalism in this context is also studied.

Les réactions multicomposants radicalaires sont d’une grande efficacité synthétique et s’avèrent en phase avec les principes de la chimie dite "verte". Ce manuscrit s’articule autour de trois axes : l’étude de la réaction de carbo-alcénylation radicalaire d’oléfines azotées riches en électrons, la valorisation des structures obtenues en se dirigeant vers la synthèse de molécules cycliques ou polycycliques complexes, et pour finir la mise au point de nouveaux médiateurs radicalaires sans étain. Dans un premiers temps, sur la base de travaux antérieurs de notre laboratoire, la réaction de carbo-alcénylation radicalaire a été étendue avec succès à l’utilisation d’énamides et d’ène-carbamates. Cette étude a permis de montrer la forte réactivité de ces oléfines vis-à-vis de radicaux électrophiles ainsi que l’importante force motrice que constitue la formation du radical amidoyle intermédiaire.Parmi tous les énamides et ène-carbamates testés, seules les structures cycliques ont permis d’obtenir une excellente diastéréosélectivité en faveur des produits trans. Dans un second temps, une valorisation des structures obtenues lors de la réaction de carbo-alcénylation a été réalisée par la mise au point de processus de cyclisations radicalaires et ioniques. Des cyclisations par activation via des énamines ont permis d’obtenir diastéréosélectivement des squelettes aza-décalones, présents notamment dans les alcaloïdes de la famille des lycopodiums. Un processus de double cyclisations de type 5-exo-trig/6-exo-trig, totalement diastéréosélectif, a également été établi donnant accès à des composés tri- et tétracycliques diversement substitués présents dans d’autres types d’alcaloïdes.Enfin, le développement de nouveaux médiateurs radicalaires silylés non réducteurs, comme substituts aux diétains, a été réalisé. L’intérêt s’est porté sur divers disilanes, thiosilanes, borosilanes et borothiosilanes, précurseurs de radicaux silyles permettant de promouvoir la propagation de chaînes radicalaires. Ces médiateurs ont été testés dans des réactions de vinylation directes de bromures d’alkyle ou dans des processus de carbo-alcénylation à trois composants. Dans le cas des thiosilanes et borosilanes des résultats encourageants et prometteurs ont été obtenus. / Multicomponent radical reactions have high synthetic efficiency and are in line with "green"chemistry concepts. This manuscript focuses on three topics: the study of the radical carboalkenylation reactions on electrons-rich olefins, the further elaboration of the structures directed towards the synthesis of complex cyclic or polycyclic molecules, and finally the development of newtin-free radical mediators.In the first part, based on previous work from our laboratory, the radical carbo-alkenylation reaction was successfully extended to enamides and ene-carbamates. This study demonstrated the high reactivity of these olefins towards electrophilic radical species and also the major driving force which constitutes the formation of the intermediate amidoyl radical. Amongst all enamides and enecarbamates tested, only the cyclic compounds led to a good diastereocontrol in the favor of transproducts.In a second part, the structures obtained in the carbo-alkenylation reaction were further elaborated through the development of radical and ionic cyclization processes. Activation via enamines allowed the diastereoselective formation of aza-decalin backbones, presents in the lycopodium alkaloid family. A totally diastereoselective double 5-exo-trig/6-exo-trig cyclization process was also achieved,generating various substituted tri- and tetracyclic compounds present in other classes of alkaloids. Finally, the development of new non-reductive free-radical silylated mediators as ditin surrogates was achieved. The research focused on various disilanes, thiosilanes, borosilanes and borothiosilanes,precursors of silyl radicals sustaining the radical chain. These mediators were tested in directvinylation reactions of alkyl bromides or in three components carbo-alkenylation processes. Forthiosilanes and borosilanes encouraging and promising results were obtained.

In Karpfen sächsischer Karpfenteichwirtschaften spielen u.a. die Zestoden Neogryporhynchus cheilancristrotus und Paradilepis scolecina und der Trematode Diplostomum pseudospathaceum eine Rolle (KAPPE 2004, PIETROCK et al. 2006, KAPPE & SEIFERT unveröff.). Weitere Fischarten (Schleie, Plötze, Regenbogenforelle) sind mit den Trematoden Diplostomum sp., Hysteromorpha triloba, Posthodiplostomum cuticola infiziert (PIETROCK et al. 2006). Mit dieser Arbeit sollte der Versuch unternommen werden, die Bedeutung Fisch fressender Vögel als Vektor Fisch pathogener Helminthen in Sachsen aufzuklären. Dafür wurden im Zeitraum von Juni 2003 bis Dezember 2004 97 Kormorane (Phalacrocorax carbo) und 46 Graureiher (Ardea cinerea) aus dem Einzugsgebiet sächsischer Teichwirtschaften auf ihren Befall mit Endohelminthen untersucht. Im Winter 2004 konnte zusätzlich ein Silberreiher (Casmerodius albus) und eine Silbermöwe (Larus argentatus) in die Untersuchungen einbezogen werden. Während des Untersuchungszeitraumes konnten so insgesamt 29 Parasitengattungen bzw. -arten nachgewiesen werden, denen z.T. kommerziell genutzte Süßwasserfische als Zwischenwirte oder paratenische Wirte dienen. Die Parasiten des Kormorans umfassten 15 verschiedene Parasitenarten. Dabei handelte es sich um die beiden Zestoden Ligula intestinalis und Paradilepis scolecina, die sechs Nematoden Baruscapillaria spp., Contracaecum rudolphii, Cyathostoma microspiculum, Desmidocercella incognita, Eucoleus contortus und Syncuaria squamata und die sieben Trematoden Clinostomum complanatum, Holostephanus dubinini, Hysteromorpha triloba, Metorchis xanthosomus, Paryphostomum radiatum, Petasiger exaeretus und P. phalacrocoracis. Außerdem wurden die zwei Kratzer Corynosoma strumosum und Polymorphus sp. nachgewiesen. Im Graureiher konnten dagegen nur neun Helminthenarten nachgewiesen werden. So der Zestode Neogryporhynchus cheilancristrotus, die sechs Trematoden Apharyngostrigea cornu, Bilharziella polonica, Diplostomum sp., Echinoasmus belocephalus, Posthodiplostomum cuticola und Tylodelphis excavata und die drei Nematoden Avioserpens galliardi, Desmidocercella incognita und Desmidocercella numidica. In der Silbermöwe konnten der Zestode Echinocotyle verschureni, die vier Trematoden Apophallus mühlingi, Diplostomum pseudospathaceum, Renicola lari und Metorchis xanthosomus sowie die drei Nematoden Desmidocercella incognita, Cosmocephalus obvelatus und Paracuaria tridentata nachgewiesen werden. Die parasitologischen Befunde des Silberreihers beschränkten sich auf Apharyngostrigea sp., Desmidocercella incognita und Desmidocercella numidica. Eine Beeinflussung der Helminthenfauna von Karpfen durch Kormoran und Reiher als auch umgekehrt konnte anhand der eigenen Untersuchungen in sächsischen Teichwirtschaften nicht sicher nachgewiesen werden. / In Saxonian carp ponds the cestodes Neogryporhynchus cheilancristrotus and Paradilepis scolecina and the trematode Diplostomum pseudospathaceum occur amongst others in carps (KAPPE 2004, PIETROCK et al. 2006, KAPPE & SEIFERT unpublished). Further fish species (tench, roach, rainbow trout) are infected with the trematodes Diplostomum sp., Hysteromorpha triloba and Posthodiplostomum cuticola (PIETROCK et al. 2006). This work was performed to analyse the importance of fish eating birds as vectors of fish pathogenic helminths. For this purpose 97 common cormorants (Phalacrocorax carbo) and 46 grey herons (Ardea cinerea) were examined on their infestation with endohelminths during the term of June 2003 to December 2004. All these birds came from the vicinity of Saxonian fish ponds. In winter 2004 additionally an egret (Casmerodius albus) and an hering gull (Larus argentatus) were included into the investigations. Altogether 29 parasite species and genus respectively could be detected. Some of these endohelminths use fresh water fishes as intermediate or paratenic hosts. The cormorants harboured 15 different parasite species and genus respectively: the two cestodes Ligula intestinalis and Paradilepis scolecina, the six nematodes Baruscapillaria carbonis, Contracaecum rudolphii, Cyathostoma microspiculum, Desmidocercella incognita, Eucoleus contortus and Syncuaria squamata and seven trematodes the Clinostomum complanatum, Holostephanus dubinini, Hysteromorpha triloba, Metorchis xanthosomus, Paryphostomum radiatum, Petasiger exaeretus and P. phalacrocoracis. In addition the two acanthocephales Corynosoma strumosum and Polymorphus sp. were detected. In the grey heron nine helminth species/genus could be detected: the cestode Neogryporhynchus cheilancristrotus, the six trematodes Apharyngostrigea cornu, Bilharziella polonica, Diplostomum sp., Echinoasmus belocephalus, Posthodiplostomum cuticola and Tylodelphis excavata and the three nematodes Avioserpens galliardi, Desmidocercella incognita and Desmidocercella numidica. In the hering gull the cestode Echinocotyle verschureni, the four trematodes Apophallus muehlingi, Diplostomum pseudospathaceum, Renicola lari and Metorchis xanthosomus as well as the three nematodes Desmidocercella incognita, Cosmocephalus obvelatus and Paracuaria tridentata were detected. Merely three endohelminths could be demonstrated in the investigated egret: Apharyngostrigea sp., Desmidocercella incognita and D. numidica. Six of the 29 endohelminth species and genus respectively were found in this examination to infest both fish and birds in Saxonian fish ponds. Nevertheless the helminth fauna of the inestigated birds, in particular of cormorants and herons did not make a definite impact on the carps´ infestation with endohelminths. As well as the fish helminth fauna were not unequivocally linked to those of the birds.

In Karpfen sächsischer Karpfenteichwirtschaften spielen u.a. die Zestoden Neogryporhynchus cheilancristrotus und Paradilepis scolecina und der Trematode Diplostomum pseudospathaceum eine Rolle (KAPPE 2004, PIETROCK et al. 2006, KAPPE & SEIFERT unveröff.). Weitere Fischarten (Schleie, Plötze, Regenbogenforelle) sind mit den Trematoden Diplostomum sp., Hysteromorpha triloba, Posthodiplostomum cuticola infiziert (PIETROCK et al. 2006). Mit dieser Arbeit sollte der Versuch unternommen werden, die Bedeutung Fisch fressender Vögel als Vektor Fisch pathogener Helminthen in Sachsen aufzuklären. Dafür wurden im Zeitraum von Juni 2003 bis Dezember 2004 97 Kormorane (Phalacrocorax carbo) und 46 Graureiher (Ardea cinerea) aus dem Einzugsgebiet sächsischer Teichwirtschaften auf ihren Befall mit Endohelminthen untersucht. Im Winter 2004 konnte zusätzlich ein Silberreiher (Casmerodius albus) und eine Silbermöwe (Larus argentatus) in die Untersuchungen einbezogen werden. Während des Untersuchungszeitraumes konnten so insgesamt 29 Parasitengattungen bzw. -arten nachgewiesen werden, denen z.T. kommerziell genutzte Süßwasserfische als Zwischenwirte oder paratenische Wirte dienen. Die Parasiten des Kormorans umfassten 15 verschiedene Parasitenarten. Dabei handelte es sich um die beiden Zestoden Ligula intestinalis und Paradilepis scolecina, die sechs Nematoden Baruscapillaria spp., Contracaecum rudolphii, Cyathostoma microspiculum, Desmidocercella incognita, Eucoleus contortus und Syncuaria squamata und die sieben Trematoden Clinostomum complanatum, Holostephanus dubinini, Hysteromorpha triloba, Metorchis xanthosomus, Paryphostomum radiatum, Petasiger exaeretus und P. phalacrocoracis. Außerdem wurden die zwei Kratzer Corynosoma strumosum und Polymorphus sp. nachgewiesen. Im Graureiher konnten dagegen nur neun Helminthenarten nachgewiesen werden. So der Zestode Neogryporhynchus cheilancristrotus, die sechs Trematoden Apharyngostrigea cornu, Bilharziella polonica, Diplostomum sp., Echinoasmus belocephalus, Posthodiplostomum cuticola und Tylodelphis excavata und die drei Nematoden Avioserpens galliardi, Desmidocercella incognita und Desmidocercella numidica. In der Silbermöwe konnten der Zestode Echinocotyle verschureni, die vier Trematoden Apophallus mühlingi, Diplostomum pseudospathaceum, Renicola lari und Metorchis xanthosomus sowie die drei Nematoden Desmidocercella incognita, Cosmocephalus obvelatus und Paracuaria tridentata nachgewiesen werden. Die parasitologischen Befunde des Silberreihers beschränkten sich auf Apharyngostrigea sp., Desmidocercella incognita und Desmidocercella numidica. Eine Beeinflussung der Helminthenfauna von Karpfen durch Kormoran und Reiher als auch umgekehrt konnte anhand der eigenen Untersuchungen in sächsischen Teichwirtschaften nicht sicher nachgewiesen werden. / In Saxonian carp ponds the cestodes Neogryporhynchus cheilancristrotus and Paradilepis scolecina and the trematode Diplostomum pseudospathaceum occur amongst others in carps (KAPPE 2004, PIETROCK et al. 2006, KAPPE & SEIFERT unpublished). Further fish species (tench, roach, rainbow trout) are infected with the trematodes Diplostomum sp., Hysteromorpha triloba and Posthodiplostomum cuticola (PIETROCK et al. 2006). This work was performed to analyse the importance of fish eating birds as vectors of fish pathogenic helminths. For this purpose 97 common cormorants (Phalacrocorax carbo) and 46 grey herons (Ardea cinerea) were examined on their infestation with endohelminths during the term of June 2003 to December 2004. All these birds came from the vicinity of Saxonian fish ponds. In winter 2004 additionally an egret (Casmerodius albus) and an hering gull (Larus argentatus) were included into the investigations. Altogether 29 parasite species and genus respectively could be detected. Some of these endohelminths use fresh water fishes as intermediate or paratenic hosts. The cormorants harboured 15 different parasite species and genus respectively: the two cestodes Ligula intestinalis and Paradilepis scolecina, the six nematodes Baruscapillaria carbonis, Contracaecum rudolphii, Cyathostoma microspiculum, Desmidocercella incognita, Eucoleus contortus and Syncuaria squamata and seven trematodes the Clinostomum complanatum, Holostephanus dubinini, Hysteromorpha triloba, Metorchis xanthosomus, Paryphostomum radiatum, Petasiger exaeretus and P. phalacrocoracis. In addition the two acanthocephales Corynosoma strumosum and Polymorphus sp. were detected. In the grey heron nine helminth species/genus could be detected: the cestode Neogryporhynchus cheilancristrotus, the six trematodes Apharyngostrigea cornu, Bilharziella polonica, Diplostomum sp., Echinoasmus belocephalus, Posthodiplostomum cuticola and Tylodelphis excavata and the three nematodes Avioserpens galliardi, Desmidocercella incognita and Desmidocercella numidica. In the hering gull the cestode Echinocotyle verschureni, the four trematodes Apophallus muehlingi, Diplostomum pseudospathaceum, Renicola lari and Metorchis xanthosomus as well as the three nematodes Desmidocercella incognita, Cosmocephalus obvelatus and Paracuaria tridentata were detected. Merely three endohelminths could be demonstrated in the investigated egret: Apharyngostrigea sp., Desmidocercella incognita and D. numidica. Six of the 29 endohelminth species and genus respectively were found in this examination to infest both fish and birds in Saxonian fish ponds. Nevertheless the helminth fauna of the inestigated birds, in particular of cormorants and herons did not make a definite impact on the carps´ infestation with endohelminths. As well as the fish helminth fauna were not unequivocally linked to those of the birds.

In this thesis 9-12 % Cr steels, used for high-temperaturecomponents in fossil-fired power plants are considered. Thecreep strength of thees steels depend on their microstructurethat consists of a matrix of tempered lath martensite withdensely distributed precipitates. The mechanical properties arestrongly influenced by precipitates present in the matrix andthe more densely distributed they are the higher is thehardening effect. These particles nucleate, grow and coarsenduring use in power plants, leading to a degradation ofmechanical properties. In this thesis the nucleation andcoarsening behaviour of the precipitates in the Cr steels aresimulated by new models and the results are compared withtransmission electron microscopy (TEM) observations of testedmaterials. A model of the nucleation of MX, which mainly isvanadium-nitrides, is presented. MX precipitates are assumed tonucleate on dislocations during annealing. The model takes intoaccount the full multicomponent thermodynamical behaviour ofthe system as well as the strain energy caused by a puredilatoric strain and the shape of the nucleus. The calculationsyield a critical size and shape represented by an oblatespheroid with a radius of a few nanometers and a thickness ofan atomic layer. This is in agreement with TEM observations ofsupercritical particles. A new coarsening model, which takes into account themulticomponent effects, is presented and it has been tested ondifferent systems to validate the model.     Four different carbides, Cr7C3, Mo6C, VC and NbC, in austenitic matrix as well asγ ' in ternary Ni-base super-alloy systems (Ni-Al-Mo)were compared with measurements from literature.     TiC-particles in austenitic stainless steel, ASTM 316Ti,were considered. The simulations were performed taking intoaccount iron and 7 alloying elements. The measurements wereperformed with TEM on samples that had been heat-treated at900° C.     MX and M23C6in a 9 % Cr steel were investigated with energyfiltering transmission electron microscopy (EFTEM) andcompared with simulations. The used samples had been heattreated for various periods of time at 600 and 650° Cfor up to 26 000 h. The agreement of the simulations with the experiments wasgood in all cases when reasonable values of the interfacialenergy, the only adjustable parameter, were chosen. Coarsening simulations were also performed to investigatethe influence of changes in composition on the coarsening rate.For MX, in a 9 % Cr steel, the coarsening rate is almostindependent of the V/Nb ratio but highly dependent on theN-content. Also the effect on the coarsening rate for M23C6by adding Co to a Cr steel was investigated bysimulation. Co is known to increase the resistance totempering. The results show that a final average radius of thecarbides after 30 000 h at 600° C decreases with 30 % witha Co addition of 10 mass %. <b>Keywords:</b>Cr steels, nucleation, coarsening, model,DICTRA, precipitates, carbides, carbo-nitrides, MX, VN, M23C6, TiC, TEM, EFTEM, Curie-temperature