Stable isotope and trace element stratigraphy across the Permian-Triassic transition: A redefinition of the boundary in the Velebit Mountain, Croatia

Stable isotopes of carbonates (delta(13)C(carb), delta(18)O(carb)), organic matter (delta(13)C(org), delta(15)N(org)) and major, trace and rare earth element (REE) compositions of marine carbonate rocks of Late Permian to Early Triassic age were used to establish the position of the Permian-Triassic boundary (PTB) at two continuous sections in the Velebit Mountain, Croatia. The chosen sections - Rizvanusa and Brezimenjaca - are composed of two lithostratigraphic units, the Upper Permian Transitional Dolomite and the overlying Sandy Dolomite. The contact between these units, characterized by the erosional features and sudden occurrence of ooids and siliciclastic grains, was previously considered as the chronostratigraphic PTB. The Sandy Dolomite is characterized by high content of non-carbonate material (up to similar to 30 wt.% insoluble residue), originated from erosion of the uplifted hinterland. A relatively rich assemblage of Permian fossils (including Geinitzina, Globivalvulina, Hemigordius, bioclasts of gastropods, ostracods and brachiopods) was found for the first time in Sandy Dolomite, 5 m above the lithologic boundary in the Rizvanusa section. A rather abrupt negative delta(13)C(carb) excursion in both sections appears in rocks showing no recognizable facies change within the Sandy Dolomite, -2 parts per thousand at Rizvanusa and -1.2 parts per thousand at Brezimenjaca, 11 m and 0.2 m above the lithologic contact, respectively. This level within the lower part of the Sandy Dolomite is proposed as the chemostratigraphic PTB. In the Rizvanusa section, the delta(13)C(org) values decline gradually from similar to-25 parts per thousand in the Upper Permian to similar to-29 parts per thousand in the Lower Triassic. The first negative delta(13)C(org) excursion occurs above the lithologic contact, within the uppermost Permian deposits, and appears to be related to the input of terrigenous material. The release of isotopically light microbial soil-biomass into the shallow-marine water may explain this sudden decrease of delta(13)C(org) values below the PTB. This would support the hypothesis that in the western Tethyan realm the land extinction, triggering a sudden drop of woody vegetation and related land erosion, preceded the marine extinction. The relatively low delta(15)N(org) values at the Permian-Triassic (P-Tr) transition level, close to approximate to 0 parts per thousand, and a secondary negative delta(13)C(org) excursion of -0.5 parts per thousand point to significant terrestrial input and primary contribution of cyanobacteria. The profiles of the concentrations of redox-sensitive elements (Ce, Mn, Fe, V), biogenic or biogenic-scavenged elements (P, Ba, Zn, V), Ce/Ce* values, and normalized trace elements, including Ba/Al, Ba/Fe, Ti/Al, Al/(Al + Fe + Mn) and Mn/Ti show clear excursions at the Transitional Dolomite-Sandy Dolomite lithologic boundary and the chemostratigraphic P-Tr boundary. The stratigraphic variations indicate a major regression phase marking the lithologic boundary, transgressive phases in the latest Permian and a gradual change into shallow/stagnant anoxic marine environment towards the P-Tr boundary level and during the earliest Triassic. (C) 2010 Elsevier B.V. All rights reserved.

Epithelial to mesenchymal transition in the pathogenesis of uterine malignant mixed Müllerian tumours: the role of ubiquitin proteasome system and therapeutic opportunities.

Malignant mixed Müllerian tumours (malignant mixed mesodermal tumours, MMMT) of the uterus are metaplastic carcinomas with a sarcomatous component and thus they are also called carcinosarcomas. It has now been accepted that the sarcomatous component is derived from epithelial elements that have undergone metaplasia. The process that produces this metaplasia is epithelial to mesenchymal transition (EMT), which has recently been described as a neoplasia-associated programme shared with embryonic development and enabling neoplastic cells to move and metastasise. The ubiquitin proteasome system (UPS) regulates the turnover and functions of hundreds of cellular proteins. It plays important roles in EMT by being involved in the regulation of several pathways participating in the execution of this metastasis-associated programme. In this review the specifi c role of UPS in EMT of MMMT is discussed and therapeutic opportunities from UPS manipulations are proposed.

Ubiquitination and the Ubiquitin-Proteasome System as regulators of transcription and transcription factorsin epithelial mesenchymal transition of cancer.

Epithelial to Mesenchymal Transition (EMT) in cancer is a process that allows cancer cells to detach from neighboring cells, become mobile and metastasize and shares many signaling pathways with development. Several molecular mechanisms which regulate oncogenic properties in neoplastic cells such as proliferation, resistance to apoptosis and angiogenesis through transcription factors or other mediators are also regulators of EMT. These pathways and downstream transcription factors are, in their turn, regulated by ubiquitination and the Ubiquitin-Proteasome System (UPS). Ubiquitination, the covalent link of the small 76-amino acid protein ubiquitin to target proteins, serves as a signal for protein degradation by the proteasome or for other outcomes such as endocytosis, degradation by the lysosome or directing these proteins to specific cellular compartments. This review discusses aspects of the regulation of EMT by ubiquitination and the UPS and underlines its complexity focusing on transcription and transcription factors regulating EMT and are being regulated by ubiquitination.

Maladies cardiovasculaires: une cible de prévention pour contrecarrer les effets de l'évolution démographique [Cardiovascular diseases: a target for prevention to thwart the effects of population aging]

The prevalence of cardiovascular diseases is high in the old age. These conditions have a negative impact on the quality of life and are associated with a high risk of disability. A marked increase in the number of affected individuals is likely, in coming decades, with population aging. Primary cardiovascular prevention, but also an early recognition of subclinical heart diseases and secondary and tertiary prevention will be of up most importance for individuals (quality of life) and for societies (burden of functional impairments) as the baby-boom generation reaches retirement age.

An evolutionary model explaining the Neolithic transition from egalitarianism to leadership and despotism.

The Neolithic was marked by a transition from small and relatively egalitarian groups to much larger groups with increased stratification. But, the dynamics of this remain poorly understood. It is hard to see how despotism can arise without coercion, yet coercion could not easily have occurred in an egalitarian setting. Using a quantitative model of evolution in a patch-structured population, we demonstrate that the interaction between demographic and ecological factors can overcome this conundrum. We model the coevolution of individual preferences for hierarchy alongside the degree of despotism of leaders, and the dispersal preferences of followers. We show that voluntary leadership without coercion can evolve in small groups, when leaders help to solve coordination problems related to resource production. An example is coordinating construction of an irrigation system. Our model predicts that the transition to larger despotic groups will then occur when: (i) surplus resources lead to demographic expansion of groups, removing the viability of an acephalous niche in the same area and so locking individuals into hierarchy; (ii) high dispersal costs limit followers' ability to escape a despot. Empirical evidence suggests that these conditions were probably met, for the first time, during the subsistence intensification of the Neolithic.

Open to closed system transition traced through the TDIC isotopic signature at the aquifer recharge stage, implications for groundwater 14C dating

14C dating models are limited when considering recent groundwater for which the carbon isotopic signature of the total dissolved inorganic carbon (TDIC) is mainly acquired in the unsaturated zone. Reducing the uncertainties of dating thus implies a better identification of the processes controlling the carbon isotopic composition of the TDIC during groundwater recharge. Geochemical interactions between gas, water and carbonates in the unsaturated zone were investigated for two aquifers (the carbonate-free Fontainebleau sands and carbonate-bearing Astian sands, France) in order to identify the respective roles of CO2 and carbonates on the carbon isotopic signatures of the TDIC; this analysis is usually approached using open or closed system terms. Under fully open system conditions, the seasonality of the 13C values in the soil CO2 can lead to important uncertainties regarding the so-called "initial 14C activity" used in 14C correction models. In a carbonate-bearing unsaturated zone such as in the Astian aquifer, we show that an approach based on fully open or closed system conditions is not appropriate. Although the chemical saturation between water and calcite occurs rapidly within the first metre of the unsaturated zone, the carbon isotopic contents (δ13C) of the CO2 and the TDIC evolve downward, impacted by the dissolution-precipitation of the carbonates. In this study, we propose a numerical approach to describe this evolution. The δ13C and the A 14C (radiocarbon activity) of the TDIC at the base of the carbonate-hearing unsaturated zone depends on (i) the δ13C and the A 14C of the TDIC in the soil determined by the soil CO2, (ii) the water's residence time in the unsaturated zone and (iii) the carbonate precipitation-dissolution fluxes. In this type of situation, the carbonate δ13C-A 14C evolutions indicate the presence of secondary calcite and permit the calculation of its accretion flux, equal to ~ 4.5 ± 0.5 x 10-9 mol grock-1 yr-1. More generally, for other sites under temperate climate and with similar properties to the Astian sands site, this approach allows for a reliable determination of the carbon isotopic composition at the base of the unsaturated zone as the indispensable "input function" data of the carbon cycle into the aquifer.

Effects of the transition time between muscle-tendon stretch and shortening on mechanical efficiency.

The net mechanical efficiency of positive work (eta(pos)) has been shown to increase if it is immediately preceded by negative work. This phenomenon is explained by the storage of elastic energy during the negative phase and its release during the subsequent positive phase. If a transition time (T) takes place, the elastic energy is dissipated into heat. The aim of the present study was to investigate the relationship between eta(pos) and T, and to determine the minimal T required so that eta(pos) reached its minimal value. Seven healthy male subjects were tested during four series of lowering-raising of the body mass. In the first series (S (0)), the negative and positive phases were executed without any transition time. In the three other series, T was varied by a timer (0.12, 0.24 and 0.56 s for series S (1), S (2) and S (3), respectively). These exercises were performed on a force platform sensitive to vertical forces to measure the mechanical work and a gas analyser was used to determine the energy expenditure. The results indicated that eta(pos) was the highest (31.1%) for the series without any transition time (S (0)). The efficiencies observed with transition times (S (1), S (2) and S (3)) were 27.7, 26.0 and 23.8%, respectively, demonstrating that T plays an important role for mechanical efficiency. The investigation of the relationship between eta(pos) and T revealed that the minimal T required so that eta(pos) reached its minimal value is 0.59 s.

IDENTITÉ, PROJET, CHANGEMENT : DES REPRÉSENTATIONS SOCIALES AUX LEVIERS DE L'ACTION PUBLIQUE. POUR UN MODE DE GOUVERNANCE AXÉ SUR LE DÉVELOPPEMENT TERRITORIAL. ETUDE DE CAS : CANTON DU JURA (SUISSE)

Thirty years after the Canton of Jura entered sovereignty, it has to be admited that the creation of the newly canton did't fullfill the hopes of economic and demografic growth that many could have expected from political independance. Through a plurality of complementary approaches, the research suggest a closer look at, on one hand, the position of the Canton in its territorial context as well as its structure and dynamics and on the other hand, the representations of the territory and its evolution by the social actors. This in order to formulate a set of social demands (of debate, of openness and of overcoming cleavages) which augurs for a new territoriality regime and testify of a requirement of reflexivity toward the state institutions and actions. The analysis allowed to set in evidence the central role of the couple identity-project in the dynamics of change, and to identifiy three main periods in the recent past of the Canton: a period of territorialization, during which grew a strong collective identity, coupled with a major project of society (the creation of the canton of Jura); then followed a period of deterritorialization, with the fragmentation of the collective identity and the lack of a project of society. Then, the third period, with a paradoxical event, the failure in public vote of the the project Jura open Land (Jura Pays ouvert), which was meant to give a second wind to the Canton. We consider this turning point as the start of a new period (of reterritorialization), with an issue linked with the outlines of a renewed "jurassian" identity and the elaboration of a shared territory project.Trente ans après l'entrée en souveraineté, force est de constater que la création du canton du Jura n'a pas permis de répondre aux espérances de développement économique et démographique que l'indépendance politique devait entraîner dans son sillage. Cette recherche se propose, à travers une pluralité d'approches complémentaires, d'examiner d'une part la position du Canton dans son contexte territorial ainsi que sa structure et sa dynamique; d'autre part, les représentations que se font les acteurs du territoire et de son évolution, pour déboucher sur une série de demandes sociales (de débat, d'ouverture et de dépassement des clivages) qui augurent de la transition vers un nouveau régime de territorialité et témoignent d'une exigence de réflexivité envers les institutions et les actions de l'Etat. L'analyse a permis de mettre en évidence le rôle central du couple identité-projet dans la dynamique de changement et d'identifier trois temps forts dans l'évolution récente du Canton, une phase de territorialisation au cours de laquelle s'est constituée une identité forte doublée d'un projet de société majeur, suivie d'une phase de déterritorialisation avec une fragmentation de l'identité collective et l'absence de projet mobilisateur. Enfin, un moment paradoxal, l'échec du projet Jura Pays ouvert, censé redonner un second souffle au Canton, qui amorce une nouvelle étape (de reterritorialisation) avec un questionnement lié aux contours d'une identité jurassienne renouvelée et à l'élaboration d'un projet de territoire partagé.Les ressorts de la production du territoire et de son développement sont analysés à travers le rôle des représentations sociales dans la constitution identitaire et le projet territorial, à l'exemple du canton du Jura. La mise en évidence du rôle central du couple identité-projet dans la dynamique de changement a permis d'identifier trois temps forts dans l'évolution récente du Canton. Une première phase (la création du canton du Jura), au cours de laquelle s'est constituée une identité forte doublée d'un projet de société majeur, suivie d'une phase au cours de laquelle l'identité collective s'est fragmentée en l'absence de projet mobilisateur (la phase de « gestion » de l'Etat). Puis un moment de rupture (l'échec du projet Jura Pays ouvert) et l'amorce d'une transition vers une nouvelle étape, avec un questionnement lié aux contours d'une identité jurassienne renouvelée, à l'élaboration d'un projet de territoire partagé, et à l'action des pouvoirs publics dans un contexte de repositionnement du Canton.

How adult specialists deal with the principles of a successful transition.

OBJECTIVES: To evaluate whether adult specialists comply with the basic principles for a successful transition of adolescents with chronic disorders, and to determine whether the characteristics of the adult specialists have an influence on applying these principles. METHODS: Out of 299 adult specialists in four French-speaking Swiss cantons, 209 (70%) answered a paper-and-pencil mailed questionnaire between May and July 2007. Only those having received the transfer of at least one adolescent in the previous 2 years (N=102) were included in the analysis. We analyzed four dependent variables: discussing common concerns of adolescent patients, seeing the patient alone, having a transition protocol, and having a previous contact with the pediatric specialist. A logistic regression was performed for each dependent variable controlling for the physicians' characteristics (number of transfers, age, gender, workplace, and perceived experience). RESULTS: Fifty-four percent of the physicians did not spend time alone with their patients, and sensitive issues such as sexuality or substance use were not widely discussed with their young patients. Most respondents (59%) did not have an established protocol, and 54% did not have any contact with the pediatric specialist. In the multivariate analyses, the adult specialists' characteristics had little impact. CONCLUSIONS: For many adolescents with chronic disorders the transition from pediatric to adult healthcare seems to be limited to a simple transfer, often lacking adequate communication between physicians. Applying simple but basic principles such as a good coordination between providers would probably improve the quality of healthcare of adolescents with chronic illness.

Administrative Transition Planning Notebook, November 15, 2006

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