999 resultados para Early Medieval


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In order to complete the study of the very rich early Tithonian (Hybonoticeras hybonotum Zone) radiolarian fauna from the Muhlheim Member of the Mornsheim Formation outcropping in the Solnhofen area, the taxa of the family Saturnalidae are described. Although rather rare, the Saturnalidae of this member contain 14 species, ten of which are new. These species belong to four genera, one of which is new (Moebicircus n. gen.), and two subfamilies (Hexasaturnalinae and Saturnalinae). The taxonomy at generic level of these late Jurassic radiolarians is founded on the basis of the position of the blades along the ring and number and morphology of the spines. Type of spines (simple or forked) has either species level value or none, depending on species. Special attention was given to anomalies, which sometimes are rather frequent, since they can give information of paleobiological and paleoecological orders. Among them frequent cases of open ring and additional spines with Dicerosaturnalis and Siamese twins skeletons with Spongosaturninus and Dicerosaturnalis are to be noted. The authors hope that this new taxonomy will give a better image of the evolution and radiation of the Saturnalidae during the Tithonian.

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Gestures are the first forms of conventional communication that young children develop in order to intentionally convey a specific message. However, at first, infants rarely communicate successfully with their gestures, prompting caregivers to interpret them. Although the role of caregivers in early communication development has been examined, little is known about how caregivers attribute a specific communicative function to infants' gestures. In this study, we argue that caregivers rely on the knowledge about the referent that is shared with infants in order to interpret what communicative function infants wish to convey with their gestures. We videotaped interactions from six caregiver-infant dyads playing with toys when infants were 8, 10, 12, 14, and 16 months old. We coded infants' gesture production and we determined whether caregivers interpreted those gestures as conveying a clear communicative function or not; we also coded whether infants used objects according to their conventions of use as a measure of shared knowledge about the referent. Results revealed an association between infants' increasing knowledge of object use and maternal interpretations of infants' gestures as conveying a clear communicative function. Our findings emphasize the importance of shared knowledge in shaping infants' emergent communicative skills.

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Oxygen uptake was studied during the establishment of cephalocaudal polarity in the very early chick embryo, i.e., 10 hr before (stage VI) and at laying (stage X). Oxygen fluxes in minute regions of the intact blastoderms were measured in vitro by scanning microspectrophotometry in the presence or absence of glucose. The oxygen consumption of the whole blastoderm remained constant (6 nmol O2 X hr-1) throughout the period studied, although the number of cells increased more than twofold. The regional oxygen fluxes varied from 0.41 to 1.13 nmol O2 X hr-1 X mm-2 at stage VI and from 0.42 to 0.70 nmol O2 X hr-1 X mm-2 at stage X. At stage VI, the oxygen flux in the center of the blastoderm was significantly higher than that in its periphery. This pattern remained evident when the values were corrected for cell number or for cytoplasmic volume. At stage X, there was a tendency for the oxygen fluxes to decrease from the posterior to the anterior regions of the area pellucida. Thus the pattern of oxidative metabolism in the late uterine embryos seems to change from radial to bilateral. This change of symmetry probably reflects the process of formation of the embryonic axis. In addition, the fact that the oxygen uptake was similar in the presence or absence of glucose suggests that early chick embryos metabolize essentially intracellular stores.

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Acquired behavioral changes have essentially been described in advanced multiple sclerosis (MS). The present study was designed to determine whether behavioral modifications specifically related to the MS pathological process could be identified in the initial phase of the disease, as compared to control patients with chronic, relapsing and progressive inflammatory disorders not involving the central nervous system (CNS). Eighty-eight early MS patients (Expanded Disability Status Scale score <or= 2.5) and 48 controls were tested. Perceived changes by informants in behavioral control, goal-directed behavior, decision making, emotional expression, insight and interpersonal relationships were assessed using the Iowa Scale of Personality Change (ISPC). Executive behavioral disturbances were screened using the Dysexecutive Questionnaire (DEX). The mean change between the premorbid and postmorbid ISPC ratings was similar in the MS [12.2 (SD 15.6)] and in the control [11.5 (SD 15.1)] group. The perceived behavioral changes (PBCs) most frequently reported in both groups were lack of stamina, lability/moodiness, anxiety, vulnerability to stress and irritability. Pathological scores in the DEX were also similar in both groups. Correlations between PBCs and DEX scores were different in MS and control groups. MS patients with cognitive impairment had a marginally higher number of PBCs than control patients (p=0.056) and a significantly higher DEXp score (p=0.04). These results suggest that (1) PBCs occurring in early MS patients were not different from those induced by comparable chronic non-CNS disorders, (2) qualitative differences in the relationship between behavioral symptoms and executive-behavioral changes may exist between MS and control groups, and (3) behavioral symptoms seem associated with cognitive deficits in MS. We further plan to assess these observations longitudinally.

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Cerebral microangiopathy (CMA) has been associated with executive dysfunction and fronto-parietal neural network disruption. Advances in magnetic resonance imaging allow more detailed analyses of gray (e.g., voxel-based morphometry-VBM) and white matter (e.g., diffusion tensor imaging-DTI) than traditional visual rating scales. The current study investigated patients with early CMA and healthy control subjects with all three approaches. Neuropsychological assessment focused on executive functions, the cognitive domain most discussed in CMA. The DTI and age-related white matter changes rating scales revealed convergent results showing widespread white matter changes in early CMA. Correlations were found in frontal and parietal areas exclusively with speeded, but not with speed-corrected executive measures. The VBM analyses showed reduced gray matter in frontal areas. All three approaches confirmed the hypothesized fronto-parietal network disruption in early CMA. Innovative methods (DTI) converged with results from conventional methods (visual rating) while allowing greater spatial and tissue accuracy. They are thus valid additions to the analysis of neural correlates of cognitive dysfunction. We found a clear distinction between speeded and nonspeeded executive measures in relationship to imaging parameters. Cognitive slowing is related to disease severity in early CMA and therefore important for early diagnostics.

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Animal models of infective endocarditis (IE) induced by high-grade bacteremia revealed the pathogenic roles of Staphylococcus aureus surface adhesins and platelet aggregation in the infection process. In humans, however, S. aureus IE possibly occurs through repeated bouts of low-grade bacteremia from a colonized site or intravenous device. Here we used a rat model of IE induced by continuous low-grade bacteremia to explore further the contributions of S. aureus virulence factors to the initiation of IE. Rats with aortic vegetations were inoculated by continuous intravenous infusion (0.0017 ml/min over 10 h) with 10(6) CFU of Lactococcus lactis pIL253 or a recombinant L. lactis strain expressing an individual S. aureus surface protein (ClfA, FnbpA, BCD, or SdrE) conferring a particular adhesive or platelet aggregation property. Vegetation infection was assessed 24 h later. Plasma was collected at 0, 2, and 6 h postinoculation to quantify the expression of tumor necrosis factor (TNF), interleukin 1α (IL-1α), IL-1β, IL-6, and IL-10. The percentage of vegetation infection relative to that with strain pIL253 (11%) increased when binding to fibrinogen was conferred on L. lactis (ClfA strain) (52%; P = 0.007) and increased further with adhesion to fibronectin (FnbpA strain) (75%; P < 0.001). Expression of fibronectin binding alone was not sufficient to induce IE (BCD strain) (10% of infection). Platelet aggregation increased the risk of vegetation infection (SdrE strain) (30%). Conferring adhesion to fibrinogen and fibronectin favored IL-1β and IL-6 production. Our results, with a model of IE induced by low-grade bacteremia, resembling human disease, extend the essential role of fibrinogen binding in the initiation of S. aureus IE. Triggering of platelet aggregation or an inflammatory response may contribute to or promote the development of IE.

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Background: Infection with EBV and a lack in vitamin D may be important environmental triggers of MS. 1,25-(OH)2D3 mediates a shift of antigen presenting cells (APC) and CD4+ T cells to a less inflammatory profile. Although CD8+ T cells do express the vitamin D receptor, a direct effect of 1,25(OH)2D3 on these cells has not been demonstrated until now. Since CD8+ T cells are important immune mediators of the inflammatory response in MS, we examined whether vitamin D directly affects the CD8+ T cell response, and more specifically if it modulates the EBV-specific CD8+ T cell response. Material and Methods: To explore whether the vitamin D status may influence the pattern of the EBV-specific CD8+ T cell response, PBMC of 10 patients with early MS and 10 healthy controls (HC) were stimulated with a pool of immunodominant 8-10 mer peptide epitopes known to elicit CD8+ T cell responses. PBMC were stimulated with this EBV CD8 peptide pool, medium (negative control) or anti- CD3/anti-CD28 beads (positive control). The following assays were performed: ELISPOT to assess the secretion of IFN-gamma by T cells in general; cytometric beads array (CBA) and ELISA to determine whichcytokines were released by EBV-specific CD8+ T cells after six days of culture; and intracellular cytokine staining assay to determine by which subtype of T cells secreted given cytokines. To examine whether vitamin D could directly modulate CD8+ T cell immune responses, we depleted CD4+ T cells using negative selection. Results: We found that pre-treatment of vitamin D had an antiinflammatory action on both EBV-specific CD8+ T cells and on CD3/ CD28-stimulated T cells: secretion of pro-inflammatory cytokines (IFNgamma and TNF-alpha) was decreased, whereas secretion of antiinflammatory cytokines (IL-5 and TGF-beta) was increased. At baseline, CD8+ T cells of early MS patients showed a higher secretion of TNFalpha and lower secretion of IL-5. Addition of vitamin D did not restore the same levels of both cytokines as compared to HC. Vitamin D-pretreated CD8+T cells exhibited a decreased secretion of IFN-gamma and TNF-alpha, even after depletion of CD4+ T cells from culture. Conclusion: Vitamin D has a direct anti-inflammatory effect on CD8+ T cells independently from CD4+ T cells. CD8+ T cells of patients with earlyMS are less responsive to the inflammatory effect of vitamin D than HC, pointing toward an intrinsic dysregulation of CD8+ T cells. The modulation of EBV-specific CD8+T cells by vitaminDsuggests that there may be interplay between these twomajor environmental factors of MS. This study was supported by a grant from the Swiss National Foundation (PP00P3-124893), and by an unrestricted research grant from Bayer to RDP.

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A major achievement of new institutionalism in economics and political science is the formalisation of the idea that certain policies are more efficient when administered by a politically independent organisation. Based on this insight, several policy actors and scholars criticise the European Community for relying too much on a multi-task, collegial, and politicised organisation, the European Commission. This raises important questions, some constitutional (who should be able to change the corresponding procedural rules?) and some political-economic (is Europe truly committed to free and competitive markets?). Though acknowledging the relevance of legal and normative arguments, this paper contributes to the debate with a positive political-scientific perspective. Based on the view that institutional equilibria raise the question of equilibrium institutions, it shows that collegiality was (a) an equilibrium institution during the Paris negotiations of 1950-51; and (b) an institutional equilibrium for the following 50 years. The conclusion points to some recent changes in the way that European competition policy is implemented, and discusses how these affect the “constitutional” principle of collegial European governance.

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Prognosis of early breast cancer patients is significantly improved with the use of adjuvant therapies. Various guidelines have been proposed to select patients who will derive the most benefit from such treatments. However, classifications have limited usefulness in subsets of patients such as those with node negative breast cancer. The 2007 St. Paul de Vence Clinical Practice Recommendations proposed to consider adjuvant therapy in accordance with the 10-year relapse-free survival reduction estimated by Adjuvant! Online. However, many limitations remain regarding the use of Adjuvant! Online. Among them, adverse prognostic and/or predictive factors such as vascular invasion, mitotic activity, progesterone receptor negativity, and HER-2 expression are not incorporated in the routine clinical decision process. Our group has therefore issued guidelines based on the consideration of both Adjuvant! Online calculations and the prognostic and/or predictive effects of these markers. In addition, web-accessible comprehensive tables summarizing these recommendations are provided.

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In the southwestern part of the Aiguilles Rouges massif (pre-Alpine basement of the Helvetic realm, western Alps), a metavolcanic sequence, newly defined as the ``Greenstone Unit'',is exposed in two NS trending belts of several 100 metres in thickness. It consists of epidote amphibolites, partly epidote and/or calcic amphibole-bearing greenschists, and small amounts of alkali feldspar-bearing greenschists, which underwent low- to medium-grade metamorphism during Visean oblique collision. Metamorphic calcic amphiboles and epidotes show strong chemical zoning, whereas metamorphic plagioclase is exclusively albitic in composition (An 1-3). The SiO2 content of the subalkaline tholeiitic to calc-alkaline suite ranges continuously from 44 wt% to 73 wt%,but andesitic rocks predominate. The majority of samples have chemical compositions close to recent subduction-related lavas; some are even restricted to recent oceanic arcs (extremely low Ta and Nb contents, high La/Nb and Th/Ta ratios). But several basaltic to basalto-andesitic samples resemble continental tholeiites (low Th/Ta, La/Nb ratio). As it is very probable that both lava types are to some extent contemporaneous, it is proposed that the Greenstone Unit represents a former oceanic volcanic are which temporarily underwent extension during which emplacement of continental tholeiite-like rocks occurred. The cause of the extension remains ambiguous. Considering palaeotectonic significance and age of other metavolcanic units in the Aiguilles Rouges massif, the Greenstone Unit most likely formed in the Early Palaeozoic.

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La transmission de l'alphabet aux Grecs est un sujet encore très débattu. Les plus anciennes inscriptions alphabétiques grecques datent du VIIIe s. av. J.-C. et une majorité d'entre elles a été trouvée dans des sites eubéens. Une trentaine a été mise au jour à Erétrie, dont 26 proviennent du sanctuaire d'Apollon Daphnéphoros. Ces inscriptions, pour la plupart inscrites sur des coupes à boire, contribuaient à personnaliser des offrandes ou à leur donner de la valeur. Le sanctuaire et les pratiques rituelles qui s'y déroulaient offraient un cadre propice à l'usage précoce de l'écriture, au moment où la polis grecque se constituait.

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This paper analyzes the early research performance of PhD graduates in labor economics, addressing the following questions: Are there major productivity differences between graduates from American and European institutions? If so, how relevant is the quality of the training received (i.e. ranking of institution and supervisor) and the research environment in the subsequent job placement institution? The population under study consists of labor economics PhD graduates who received their degree in the years 2000 to 2005 in Europe or the USA. Research productivity is evaluated alternatively as the number of publications or the quality-adjusted number of publications of an individual. When restricting the analysis to the number of publications, results suggest a higher productivity by graduates from European universities than from USA universities, but this difference vanishes when accounting for the quality of the publication. The results also indicate that graduates placed at American institutions, in particular top ones, are likely to publish more quality-adjusted articles than their European counterparts. This may be because, when hired, they already have several good acceptances or because of more focused research efforts and clearer career incentives.