La titulatura faraònica dels emperadors romans: un cas particular de la imitatio Alexandri

Estudi realitzat a partir d’una estada a la University of Oxford, Gran Bretanya, entre 2010 i 2012. Durant l’estada postdoctoral a la University of Oxford s’han efectuat dos estudis relacionats amb l’onomàstica dels faraons d’Egipte i que constitueixen una continuació de l’anàlisi de la titulatura d’Alexandre el Gran realitzada prèviament per l’investigador en la seva recerca doctoral. El primer estudi examina la titulatura faraònica dels emperadors romans en comparació amb la d’Alexandre i, en especial, la significació ideològica i política dels paral•lelismes onomàstics existents entre elles, els quals han estat analitzats en el marc de la imitatio-aemulatio-comparatio Alexandri. Per al cas d’August, s’ha arribat a la conclusió que l’adopció de determinats apel•latius egipcis utilitzats anteriorment per Alexandre pot ser interpretada com un exemple local o estrictament egipci d’imitatio Alexandri, mentre que, en relació amb la resta d’emperadors, atès que les seves titulatures faraòniques es basen o imiten la del primer emperador, aquestes represes han de ser vistes més aviat com un exemple d’imitatio (o comparatio) Augusti. El segon estudi versa sobre la titulatura faraònica egípcia i la tradició annalística. A partir d’una anàlisi comparativa dels protocols onomàstics dels fundadores de cadascuna de les dinasties, s’ha intentat determinar si determinats noms o epítets s’empren de forma recurrent i d’una manera deliberada per tal de senyalar canvis dinàstics, és a dir, noves realitats polítiques. En concret, s’ha pretès establir fins a quin punt determinats recursos onomàstics tenen el seu reflex en la divisió en dinasties de Manetó i, alhora, determinar en quina mesura l’estudi de l’onomàstica faraònica pot contribuir al coneixement de com els egipcis conceptualitzaren i organitzaren el seu propi passat.

Selective neurodegeneration induced in rotation-mediated aggregate cell cultures by a transient switch to stationary culture conditions: a potential model to study ischemia-related pathogenic mechanisms.

Aggregating brain cell cultures at an advanced maturational stage (20-21 days in vitro) were subjected for 1-3 h to anaerobic (hypoxic) and/or stationary (ischemic) conditions. After restoration of the normal culture conditions, cell loss was estimated by measuring the release of lactate dehydrogenase as well as the irreversible decrease of cell type-specific enzyme activities, total protein and DNA content. Ischemia for 2 h induced significant neuronal cell death. Hypoxia combined with ischemia affected both neuronal and glial cells to different degrees (GABAergic neurons>cholinergic neurons>astrocytes). Hypoxic and ischemic conditions greatly stimulated the uptake of 2-deoxy-D-glucose, indicating increased glucose consumption. Furthermore, glucose restriction (5.5 mM instead of 25 mM) dramatically increased the susceptibility of neuronal and glial cells to hypoxic and ischemic conditions. Glucose media concentrations below 2 mM caused selective neuronal cell death in otherwise normal culture conditions. GABAergic neurons showed a particularly high sensitivity to glucose restriction, hypoxia, and ischemia. The pattern of ischemia-induced changes in vitro showed many similarities to in vivo findings, suggesting that aggregating brain cell cultures provide a useful in vitro model to study pathogenic mechanisms related to brain ischemia.

Bristle pattern formation in the thorax formation of Drosophila: a systems level approach

A fundamental question in developmental biology is how tissues are patterned to give rise to differentiated body structures with distinct morphologies. The Drosophila wing disc offers an accessible model to understand epithelial spatial patterning. It has been studied extensively using genetic and molecular approaches. Bristle patterns on the thorax, which arise from the medial part of the wing disc, are a classical model of pattern formation, dependent on a pre-pattern of trans-activators and –repressors. Despite of decades of molecular studies, we still only know a subset of the factors that determine the pre-pattern. We are applying a novel and interdisciplinary approach to predict regulatory interactions in this system. It is based on the description of expression patterns by simple logical relations (addition, subtraction, intersection and union) between simple shapes (graphical primitives). Similarities and relations between primitives have been shown to be predictive of regulatory relationships between the corresponding regulatory factors in other Systems, such as the Drosophila egg. Furthermore, they provide the basis for dynamical models of the bristle-patterning network, which enable us to make even more detailed predictions on gene regulation and expression dynamics. We have obtained a data-set of wing disc expression patterns which we are now processing to obtain average expression patterns for each gene. Through triangulation of the images we can transform the expression patterns into vectors which can easily be analysed by Standard clustering methods. These analyses will allow us to identify primitives and regulatory interactions. We expect to identify new regulatory interactions and to understand the basic Dynamics of the regulatory network responsible for thorax patterning. These results will provide us with a better understanding of the rules governing gene regulatory networks in general, and provide the basis for future studies of the evolution of the thorax-patterning network in particular.

"In vitro" reconstitution of the fragmentation of vacuoles

Résumé La fragmentation des membranes est un processus commun à beaucoup d'organelles dans une cellule. Les mitochondries, le noyau, le réticulum endoplasmique, les phagosomes, les peroxisomes, l'appareil de Golgi et les lysosomes (vacuoles chez la levure) se fragmentent en plusieurs copies en réponse à des sitmulis environnementaux, tels que des stresses, ou dans une situtation normale durant le cycle cellulaire, afin d' être transférer dans les cellules filles. La fragmentation des membranes est également observée pendant le processus d'endocytose, lors de la formation de vésicules endocytiques, mais également dans tout le traffic intracellulaire, lors de la genèse d'une vésicule de transport. Le processus de fragmentation est donc généralement important. La découverte en 1991 d'une dynamin-like GTPase comme protéine impliquée dans la fragmentation de la membrane plasmique durant l'endocytose a ouvert ce domaine de recherche. Dès lors des dynamines ont été découvertes sur la pluspart des organelles, ce qui suggère un processus de fragmentation des membranes commun à l'ensemble de la cellule. Cependant, l'ensemble des protéines impliquées ainsi que le mécanisme de la fragmentation reste encore à élucider. Mon projet de thèse était d'établir un test in vitro de fragmentation des vacuoles utile à la compréhension du mécanisme de ce processus. Le choix de ce système est judicieux pour plusieurs raisons; premièrement les vacuoles fragmentent naturellement durant le cycle cellulaire, deuxièment leur taille permet de visualiser facilement leur morphologie par simple microscopie optique, finalement elles peuvent être isolées en quantité intéressante avec un haut degré de pureté. In vivo, les vacuoles peuvent être facilement fragmentées par un stress osmotique. Un tel test permet d'identifier des protéines impliquées dans le mécanisme comme dans le criblage que j'ai effectué sur l'ensemble de la collection de délétions des gènes non-essentiels chez la levure. Cependant un test in vitro est ensuite indispensable pour jouer avec les protéines découvertes afin d'en élucider le mécanisme. Avec mon test in vitro, j'ai confirmé l'implication des protéines SNAREs dans la fragmentation et j'ai permis de comprendre la régulation de la quantité de vacuoles et de leur taille par le complexe TORC1 dans une situation de stress. 7 Résumé large public Les cellules de chaque organisme sont composées de différents compartiments appelés organelles. Chacun possède une fonction bien définie afin de permettre la vie et la croissance de la cellule. Ils sont entourés de membrane, qui joue le role de barrière spécifiquement perméable, afin de garder l'intégrité de chacun. Dans des conditions de croissance normale, les cellules prolifèrent. Durant la division cellulaire amenant à la formation d'une nouvelle cellule, chaque organelle doit se diviser afin de fournir l'ensemble des organelles à la cellule fille. La division de chaque organelle nécessite la fragmentation de la membrane les entourant. Des protéines dynamine-like GTPase ont été découvertes sur presque l'ensemble des organelles d'une cellule. Elles sont impliquées dans les processus de fragmentation des membranes. Dès lors l'idée d'un mécanisme commun est apparu. Cependant cette réaction, par sa complexité, ne peut pas impliquer une protéine unique. La découverte d'autres facteurs et la compréhension du mécanisme reste à faire. La première étape peut se faire par étude in vivo, c'est-à-dire avec des cellules entières, la deuxième étape, quant à elle, nécessite d'isoler les protéines impliquées et de jouer avec les différents paramètres, ce qui signifie donc un travail in vitro, séparé des cellules. Mon travail a constisté à établir un procédé expérimental in vitro pour étudier la fragmentation des membranes. Je travaille avec des vacuoles de levures pour étudier les réactions membranaires. Les vacuoles sont les plus grandes organelles présentes dans les levures. Elles sont impliquées principalement dans la digestion. Comme toute organelle, elles se fragmentent durant la division cellulaire. Le procédé expérimental comporte une première étape, l'isolation des vacuoles et, deuxièmement, l'incubation de celles-ci avec des composés essentiels à la réaction. En parallèle, j'ai mis en évidence, par un travail in vivo, de nouvelles protéines impliquées dans le processus de fragmentation des membranes. Ceci a été fait en réalisant un criblage par microscopie d'une collection de mutants. Parmi ces mutants, j'ai cherché ceux qui présentaient un défaut dans la fragmentation des vacuoles. Ces deux procédés expérimentaux, in vitro et in vivo, m'ont permis de découvrir de nouvelles protéines impliquées dans cette réaction, ainsi que de mettre en évidence un mécanisme utlilisé par la cellule pour réguler la fragmentation des vacuoles. 8 Summary Fragmentation of membranes is common for many organelles in a cell. Mitochondria, nucleus, endoplasmic reticulum, phagosomes, peroxisomes, Golgi and lysosomes (vacuoles in yeast) fragment into multiple copies in response to environmental stimuli, such as stresses, or in a normal situation during the cell cycle in order to be transferred into the daughter cell. Fragmentation of membrane occurs during endocytosis, at the latest step in endocytic vesicle formation, and also in intracellular trafficking, when traffic vesicles bud. This field of research was opened in 1991 when a dynamin-like GTPase was found to be involved in fragmentation of the plasma membrane during endocytosis. Since dynamin-like GTPases have been found on most organelles, similarities in their mechanisms of fragmentation might exist. However, many proteins involved in the mechanism of fragmentation remain unknown. My thesis project was to establish an in vitro assay for membrane fragmentation in order to create a tool to study the mechanism of this process. I chose vacuoles as a model organelle for several reasons: first of all, vacuoles fragment under physiological conditions during cell cycle, secondly their size makes their morphology easily visible under the light microscope, and finally vacuoles can be isolated in good amounts with relatively high degrees of purity. In vivo, vacuole fragmentation can be induced with an osmotic shock. Such a simple assay facilitates the identification of new proteins involved in the process. I used this tool to screen of the entire knockout collection of non-essential genes in Saccharomyces cerevisiae for mutants defective in vacuole fragmentation. The in vitro system will be useful to characterize the mutants and to study the mechanism of fragmentation in detail. I used my in vitro assay to confirm the involvement of vacuolar SNARE proteins in fragmentation of the organelle and to uncover that number and size of vacuoles in the cell is regulated by the TORC1 complex via selective stimulation of fragmentation activity.

Exploring the conditions for a mortality crisis: bringing context back into the debate

This study engages with the debate over the mortality crises in the former Soviet Union and Central and Eastern Europe by 1) considering at length and as complementary to each other the two most prominent explanations for the post-communist mortality crisis, stress and alcohol consumption; 2) emphasizing the importance of context by exploiting systematic similarities and differences across the region. Differential mortality trajectories reveal three country groups that cluster both spatially and in terms of economic transition experiences. The first group are the countries furthest west in which mortality rates increased minimally after the transition began. The second group experienced a severe increase in mortality rates in the early 1990s, but recovered previous levels within a few years. These countries are located peripherally to Russia and its nearest neighbours. The final group consists of countries that experienced two mortality increases or in which mortality levels had not recovered to pre-transition levels well into the 21st century. Cross-sectional time-series data analyses of men’s and women’s age and cause-specific death rates reveal that the clustering of these countries and their mortality trajectories can be partially explained by the economic context, which is argued to be linked to stress and alcohol consumption. Above and beyond many basic differences in the country groups that are held constant—including geographically and historically shared cultural, lifestyle and social characteristics—poor economic conditions account for a remarkably consistent share of excess age-specific and cause-specific deaths.

On the morphological nature of spanish adverbs ending in -mente

The morphological status of adverbs ending in -mente in Spanish (-ly in English) has been the object of many studies and continues to be the subject of debate. The two main proposals regarding the morphology of these adverbs treat them as either compounds or derivatives as the result of suffixation, but bothhypotheses present problems. In this study an analysis will be defended which treats -mente as a phrasal affix (cf. Zwicky 1987, Nevis 1985 and Miller 1992). The notion of phrasal affix has been used to describe clitics which, from a morphological standpoint, are similar to affixes but which, simultaneously manifest characteristics of independent words. The argument for analyzing -mente as a phrasal affix is based on both synchronic and diachronic data, including some similarities with object clitic pronouns.

Some applications of FISST to wireless communications

This paper aims at illustrating some applications of Finite Random Set (FRS) theory to the design and analysis of wireless communication receivers, and at pointing out similarities and differences between this scenario and that pertaining to multi-target tracking, where the use of FRS has been traditionally advocated. Two case studies are considered, l.e., multiuser detection in a dynamic environment, and multicarrier (OFDM) transmission on a frequency-selective channel. Detector designand performance evaluation are discussed, along with the advantages of importing FRS-based estimation techniques to the context of wireless communications.

ATS3-testausjärjestelmän evaluointi

Työ tehtiin Nokia Technology Platforms S60 Mobile Runtime-yksikölle. Työn tavoitteena oli evaluoida ATS3-testausjärjestelmä. ATS3-järjestelmällä voidaan automatisoida ohjelmistotestausta. Evaluoinnilla pyrittiin selvittämään voidaanko tuotekehitysvaiheessa oleva järjestelmä ottaa jo käyttöön vai vaatiiko se vielä lisäkehitystä. Työssä kerrotaan aluksi yleisesti ohjelmistotestauksesta. Siinä käydään läpi myös testausprosessin vaiheet sekä kerrotaan lyhyesti avuksi kehitetyistä työkaluista. Työssä kerrotaan myös ATS3-järjestelmän edeltäjien ominaisuuksista, sekä miten ne eroavat tarkastelun kohteena olevasta järjestelmästä. Varsinainen evaluointi alkoi tutustumalla ja asentamalla järjestelmä. Tämän jälkeen suoritettiin samat testit sekä ATS2.x-järjestelmässä että ATS3-järjestelmäss. Testauksen jälkeen analysoitiin testitulosten yhdenmukaisuuden perusteella, voidaanko siirtyä käyttömään ATS3-järjestelmää. Testitulokset olivat käytännässä yhdenmukaiset suoritettaessa testejä matkapuhelimessa, mutta emulaattoritestaus täytyi jättää väliin. Lukuisista yrityksistä sekä järjestelmän kehittäjän avusta huolimatta testejä ei onnistuttu suorittamaan ATS3-järjestelmän emulaattoriympäristössä. Näin ollen päädyttiin tulokseen, ettei järjestelmää voida ottaa vielä käytöön emulaattoritestauksessa, vaan se vaatii lisätutkimusta sekä perehtymistä järjestelmään.

Young people, parents and radical right voting: The case of the Swiss People's Party

It is commonly found that young people tend to adopt the political party choice of their parents. However, far less is known about the applicability of this theory when investigating radical right support. Using the Swiss Household panel data (1999e2007), this study empirically identifies the relationship between parents' preference for the Swiss radical right party SVP and their attitudes toward immigrants and the EU, and their offspring's preference for the SVP. Disaggregating fathers' and mothers' influence reveals that in particular, mothers' SVP support plays a role in SVP support among young people, even after controlling for educational similarities. We also demonstrate that girls are more likely to be influenced by their mothers than are boys. Furthermore, parents' negative attitudes toward the EU exert a positive influence on their children's radical right voting, independent of their voting pattern.

International nursing : cultivating a culture of empowerment

International nursing has been a growing phenomenon throughout the globe. International nurses have been found to be an asset to healthcare organizations and an important part of the health care team. However, growing concern for the plight of international nurses facing obstacles such as professional stagnation and exploitation has spurred the development of strategies to mitigate and ameliorate the experiences of nurses working abroad. In this respect, the purpose of this study was to explore the management-influenced factors and the nurse team-influenced factors that promote the empowerment of the international nurse in the health care setting. The methodology used in this study was a systemic review. After a rigorous search for relevant empirical studies using OVID database, eight empirical research studies were selected using systematic review methodology to collect, analyze and synthesize data. The selected eight empirical studies were then subjected to a content analysis. The results suggested that the empowerment of an international nurse is inseparable from the empowerment of the health care organization. Based on the findings in this study, strategies to promote international nurses were found to mirror strategies evidenced to empower the nursing organization. Some of the management-influenced factors which were found to facilitate empowerment included a diversity rich work culture, transformational leadership at the management level, and a responsibility to foster the values of the organization. The team-influenced factors which were found to contribute to the empowerment of the international nurse included a united mutually-interdependent nurse team, shared accountability among the members of the nurse team, and the building of trust in work relationships. To conlude, this study indicates that efforts to empower international nurses without considering the work culture and the organization as a whole are futile because empowerment cannot take place in an environment that lacks antecedent conditions. Strategies to empower the international nurse should not focus on the deficits and special needs of the international nurse, but should focus on the similarities and commonalities of the nursing body. Empowerment of the international nurse mean open honest communication, supportive work environment, and a firm policy to quell disruptive elements that threaten the organization's values, mission, and philosophy of care.

Essays on the principles and adoption of entreprise-wide architecture

Enterprise-wide architecture has become a necessity for organizations to (re)align information technology (IT) to changing business requirements. Since a city planning metaphor inspired enterprise-wide architecture, this dissertation's research axes can be outlined by similarities between cities and enterprises. Both are characterized as dynamic super-systems that need to address the evolving interest of various architecture stakeholders. Further, both should simultaneously adhere to a set of principles to guide the evolution of architecture towards the expected benefits. The extant literature on enterprise-wide architecture not only disregards architecture adoption's complexities but also remains vague about how principles guide architecture evolution. To bridge this gap, this dissertation contains three interrelated research streams examining the principles and adoption of enterprise-wide architecture. The first research stream investigates organizational intricacies inherent in architecture adoption. It characterizes architecture adoption as an ongoing organizational adaptation process. By analyzing organizational response behaviors in this adaptation process, it also identifies four archetypes that represent very diverse architecture approaches. The second research stream ontologically clarifies the nature of architecture principles along with outlining new avenues for theoretical contributions. This research stream also provides an empirically validated set of principles and proposes a research model illustrating how principles can be applied to generate expected architecture benefits. The third research stream examines architecture adoption in multinational corporations (MNCs). MNCs are Specified by unique organizational characteristics that constantly strive for balancing global integration and local responsiveness. This research stream characterizes MNCs' architecture adoption as a continuous endeavor. This endeavor tries to constantly synchron ize architecture with stakeholders' beliefs about how to balance global integration and local responsiveness. To conclude, this dissertation provides a thorough explanation of a long-term journey in Which organizations learn over time to adopt an effective architecture approach. It also clarifies the role of principles to purposefully guide the aforementioned learning process. - L'Architecture d'Entreprise (AE) est devenue une nécessité pour permettre aux organisations de (ré)aligner les technologies de l'information (TI) avec les changements en termes de besoins métiers. En se basant sur la métaphore de la planification urbaine dont l'AE s'est inspirée, cette dissertation peut être présentée comme une comparaison entre les villes et les entreprises; les deux sont des super-systèmes dynamiques ayant besoin de répondre aux intérêts d'acteurs divers et variés en constants évolution. De plus, les deux devraient souscrire simultanément à un ensemble de principes afin de faire converger l'évolution de l'architecture vers les bénéfices attendus. La littérature sur l'AE, non seulement ne prend pas en considération les complexités de l'adoption d'architecture, mais aussi reste vague sur la manière dont les principes guident l'évolution de l'architecture. Pour pallier ce manque, cette dissertation est composée de trois volets de recherche étroitement liés examinant les principes et l'adoption de l'AE. Le premier volet examine la complexité organisationnelle inhérente à l'adoption de l'architecture. Il caractérise l'adoption de l'architecture en tant que processus d'adaptation continu. En analysant le comportement organisationnel en réponse à ce processus d'adaptation, ce volet distingue quatre archétypes représentant la diversité des approches de l'architecture. Le deuxième volet de recherche clarifie de manière ontologique la nature des principes d'architecture et envisage les contributions théoriques futures possibles. Cet axe de recherche fournit aussi un ensemble de principes, validés de manière empirique, et propose un modèle de recherche illustrant la manière dont ces principes peuvent être appliqués afin de générer les bénéfices attendus de l'architecture. Le troisième volet examine l'adoption de l'architecture dans les entreprises multinationales. Ces dernières possèdent des caractéristiques organisationnelles uniques et sont constamment à la recherche d'un équilibre entre une intégration globale et une flexibilité locale tout en prenant en compte les convictions des divers acteurs sur la manière d'atteindre cet équilibre. Pour conclure, cette dissertation fournit une explication sur le long voyage au cours duquel les entreprises apprennent à adopter une approche d'architecture efficace. Elle clarifie aussi le rôle des principes dans l'accompagnement de ce processus d'apprentissage.

A Comparison of the Management Models of Protected Areas between China and the Southern African Region

A Comparison of the Management Models of Protected Areas between China and the African South Region allows reading and evaluating the similarities and differences in the use of management model as a management tool for protected areas in China and South African Region. Specifically, some positive and negative features of the management approaches for the two regions. Secondary data was collected from various related literature such as policy documents, students‟ dissertations/thesis, scientific articles and magazines. Based on the method above, the study found out that China's first nature reserve was the Dingus Mountain Nature Reserve in Zhaoqing, Guangdong province established in 1956. By the end of 2005, about 2,349 nature reserves of various kinds were set up throughout the country, covering a total area of 149.95 million ha and accounting for 15 percent of the total land territory. The study further found that Southern Africa has approximately 4,390 protected areas out of 11487920 total land areas and Eastern Africa has approximately 1838144 protected areas, which is equivalent to 15.0% of the total land areas. South Africa in this region had its first declared natural park in 1926 after Paul Kruger (a war hero) had alerted the authorities of the extinguishing threat of some animal species of region.

Mapping the nursing care with the NIC for patients in risk for pressure ulcer

Objective:To identify the nursing care prescribed for patients in risk for pressure ulcer (PU) and to compare those with the Nursing Interventions Classification (NIC) interventions. Method: Cross mapping study conducted in a university hospital. The sample was composed of 219 adult patients hospitalized in clinical and surgical units. The inclusion criteria were: score ≤ 13 in the Braden Scale and one of the nursing diagnoses, Self-Care deficit syndrome, Impaired physical mobility, Impaired tissue integrity, Impaired skin integrity, Risk for impaired skin integrity. The data were collected retrospectively in a nursing prescription system and statistically analyzed by crossed mapping. Result: It was identified 32 different nursing cares to prevent PU, mapped in 17 different NIC interventions, within them: Skin surveillance, Pressure ulcer prevention and Positioning. Conclusion: The cross mapping showed similarities between the prescribed nursing care and the NIC interventions.

Pneumopathie interstitielle granulomato-lymphocytaire dans l'immunodéficience commune variable [Granulomatous lymphocytic interstitial lung disease in common variable immunodeficiency].

Common variable immunodeficiency (CVID) is the most frequent primary immune deficiency. Recurrent infections are classical consequences of CVID, but their impact has been largely reduced by immunoglobulin replacement. CVID is also associated with various inflammatory and autoimmune manifestations resulting from abnormal cellular immunity. The lungs are especially affected by a recently described entity called granulomatous lymphocytic interstitial lung disease (GLILD). GLILD currently constitutes an important cause of morbidity and mortality in these patients. It is distinct from bronchiectasis secondary to recurrent infections, and presents similarities but also striking differences with sarcoidosis.

Late Early Triassic climate change: Insights from carbonate carbon isotopes, sedimentary evolution and ammonoid paleobiogeography

The late Early Triassic sedimentary-facies evolution and carbonate carbon-isotope marine record (delta(13)C(carb)) of ammonoid-rich, outer platform settings show striking similarities between the South ChinaBlock (SCB) and the widely distant Northern Indian Margin (NIM). The studied sections are located within the Triassic Tethys Himalayan belt (Losar section, Himachal Pradesh, India) and the Nanpanjiang Basin in the South China Block (Jinya section, Guangxi Province), respectively. Carbon isotopes from the studied sections confirm the previously observed carbon cycle perturbations at a time of major paleoceanographic changes in the wake of the end-Permian biotic crisis. This study documents the coincidence between a sharp increase in the carbon isotope composition and the worldwide ammonoid evolutionary turnover (extinction followed by a radiation) occurring around the Smithian-Spathian boundary. Based on recent modeling studies on ammonoid paleobiogeography and taxonomic diversity, we demonstrate that the late Early Triassic (Smithian and Spathian) was a time of a major climate change. More precisely, the end Smithian climate can be characterized by a warm and equable climate underlined by a flat, pole-to-equator, sea surface temperature (SST) gradient, while the steep Spathian SST gradient suggests latitudinally differentiated climatic conditions. Moreover, sedimentary evidence suggests a transition from a humid and hot climate during the Smithian to a dryer climate from the Spathian onwards. By analogy with comparable carbon isotope perturbations in the Late Devonian, Jurassic and Cretaceous we propose that high atmospheric CO(2) levels could have been responsible for the observed carbon cycle disturbance at the Smithian-Spathian boundary. We suggest that the end Smithian ammonoid extinction has been essentially caused by a warm and equable climate related to an increased CO(2) flux possibly originating from a short eruptive event of the Siberian igneous province. This increase in atmospheric CO(2) concentrations could have additionally reduced the marine calcium carbonate oversaturation and weakened the calcification potential of marine organisms, including ammonoids, in late Smithian oceans. (c) 2006 Elsevier B.V. All rights reserved.