773 research outputs found

    Comparing Welfare Regime Changes: Living Standards and the Unequal Life Chances of Different Birth Cohorts

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    The cohort sustainability of welfare regimes is of central importance to most long-term analyses of welfare state reforms (see for example: Esping-Andersen et al., 2002). A complement to these analyses shows that changes in intra versus inter cohort inequalities are major outcomes or consequences of the trajectories of the different welfare regimes. Previous comparative research papers show the difference between France and the United-States, since the American intra-cohort inequalities have increased strongly for the last three decades, when the French case show less intra-cohort inequalities and more inter-cohort imbalances at the expense of younger generations of adults (Chauvel 2006). Here, we propose a comparison between the US, Danish, French, and Italian dynamics of distribution of after tax and transfers equivalised income by age, period and cohort, to assess how different welfare regimes gave different trade-offs between intra and inter cohort inequality. The Luxembourg Income Study (LIS) data are used to analyze the transformations of the intra cohort inequalities (based on interdecile ratios) and the changes in the cohort life chances. The main result is that the conservative and the familialistic welfare regimes are marked by more inter-cohort inequalities to the expense of young social generations, who are relatively impoverished, when the social-democrat and the liberal ones show less inter-cohort redistribution of resources, but increasing intra-cohort inequality, particularly in the case of the US. In terms of cohort sustainability of welfare regimes, the French and Italian dynamics seem to be unsustainable since the contemporary well-off seniors are flowed by impoverished mid-aged groups who will be poor seniors of the 2020s

    Changes of the forest-savanna boundary in Brazilian Amazonia during the holocene revealed by stable isotope ratios of soil organic carbon

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    The possibility of ecosystem boundary changes in northern Brazilian Amazonia during the Holocene period was investigated using soil organic carbon isotope ratios. Determination of past and present fluctuations of the forest-savanna boundary involved the measurement of natural 13C isotope abundance, expressed as delta 13C, in soil organic matter (SOM). SOM 13C analyses and radiocarbon dating of charcoal fragments were carried out on samples derived from soil profiles taken along transects perpendicular to the ecotonal boundary. SOM delta 13C values in the upper soil horizons appeared to be in equilibrium with the overlying vegetation types and did not point to a movement of the boundary during the last decades. However, delta 13C values obtained from deeper savanna and forest soil layers indicated that the vegetation type has changed in the past. In current savanna soil profiles, we observed the presence of mid-Holocene charcoals derived from forest species : fire frequency at that time was probably greater, and more extensive savanna may have resulted. Isotope data and the presence of these charcoals thus suggest that the forest-savanna boundary has shifted significantly in the recent Holocene period, forest being more extensive during the early Holocene than today. During the middle Holocene, the forest could have strongly regressed, and fires appeared, with a maximum development of the savanna vegetation. At the beginning of the late Holocene, the forest may have invaded a part of this savanna, and fires occurred again. (Résumé d'auteur

    The size of plume heterogeneities constrained by Marquesas isotopic stripes

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    International audienceThe scale and geometry of chemical and isotopic heterogeneities in the source of plumes have important scientific implications on the nature, composition and origin of plumes and on the dynamics of mantle mixing over time. Here, we address these issues through the study of Marquesas Islands, one of the Archipelagoes in Polynesia. We present new Sr, Nd, Pb, Hf isotopes as well as trace element data on lavas from several Marquesas Islands and demonstrate that this archipelago consists of two adjacent and distinct rows of islands with significantly different isotopic compositions. For the entire 5.5 Ma construction period, the northern islands, hereafter called the Ua Huka group, has had systematically higher 87Sr/86Sr and lower 206Pb/204Pb ratios than the southern Fatu Hiva group at any given 143Nd/144Nd value. The shape and curvature of mixing arrays preclude the ambient depleted MORB mantle as one of the mixing end-members. We believe therefore that the entire isotopic heterogeneity originates in the plume itself. We suggest that the two Marquesas isotopic stripes originate from partial melting of two adjacent filaments contained in small plumes or "plumelets" that came from a large dome structure located deep in the mantle under Polynesia. Low-degree partial melting under Marquesas and other "weak" Polynesian hot spot chains (Pitcairn-Gambier, Austral-Cook, Society) sample small areas of the dome and preserve source heterogeneities. In contrast, more productive hot spots build up large islands such as Big Island in Hawaii or RĂ©union Island, and the higher degrees of melting blur the isotopic variability of the plume source

    Différenciation hémisphérique auditive par analyse de potentiels évoqués auditifs

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    - Par opposition aux Ă©tudes subjectives adressant le problĂšme de la spĂ©cialisation hĂ©misphĂ©rique auditive, le but de ce travail est de proposer des mesures objectives permettant de diffĂ©rencier le comportement des deux hĂ©misphĂšres vis-Ă -vis des stimuli. Pour ce faire, nous disposons de signaux intracĂ©rĂ©braux enregistrĂ©s en rĂ©ponse Ă  divers stimuli. Ce papier ne traite que des rĂ©ponses aux sons verbaux voisĂ© /ba/, non voisĂ© /pa/ et Ă  la voyelle /a/ et prĂ©sente trois mĂ©thodes. La premiĂšre calcule le coefficient de corrĂ©lation entre les rĂ©ponses Ă  deux stimuli, recueillies sur le mĂȘme plot. La seconde porte sur l'Ă©volution de la corrĂ©lation au cours du temps. Sur les valeurs de corrĂ©lation obtenues est effectuĂ©e une analyse factorielle des correspondances (AFC) suivie d'une classification hiĂ©rarchique ascendante appliquĂ©e sur les facteurs de l'AFC. Finalement, les rĂ©ponses sont caractĂ©risĂ©es selon le nombre d'extrema en fonction de l'hĂ©misphĂšre et du stimulus considĂ©rĂ©s. Les trois mĂ©thodes permettent de mettre en avant certains paramĂštres rĂ©vĂ©lateurs de diffĂ©rence de comportement des deux hĂ©misphĂšres

    Identification and Characterization of Mediators of Fluconazole Tolerance in Candida albicans.

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    Candida albicans is an important human pathogen and a major concern in intensive care units around the world. C. albicans infections are associated with a high mortality despite the use of antifungal treatments. One of the causes of therapeutic failures is the acquisition of antifungal resistance by mutations in the C. albicans genome. Fluconazole (FLC) is one of the most widely used antifungal and mechanisms of FLC resistance occurring by mutations have been extensively investigated. However, some clinical isolates are known to be able to survive at high FLC concentrations without acquiring resistance mutations, a phenotype known as tolerance. Mechanisms behind FLC tolerance are not well studied, mainly due to the lack of a proper way to identify and quantify tolerance in clinical isolates. We proposed here culture conditions to investigate FLC tolerance as well as an easy and efficient method to identity and quantify tolerance to FLC. The screening of C. albicans strain collections revealed that FLC tolerance is pH- and strain-dependent, suggesting the involvement of multiple mechanisms. Here, we addressed the identification of FLC tolerance mediators in C. albicans by an overexpression strategy focusing on 572 C. albicans genes. This strategy led to the identification of two transcription factors, CRZ1 and GZF3. CRZ1 is a C2H2-type transcription factor that is part of the calcineurin-dependent pathway in C. albicans, while GZF3 is a GATA-type transcription factor of unknown function in C. albicans. Overexpression of each gene resulted in an increase of FLC tolerance, however, only the deletion of CRZ1 in clinical FLC-tolerant strains consistently decreased their FLC tolerance. Transcription profiling of clinical isolates with variable levels of FLC tolerance confirmed a calcineurin-dependent signature in these isolates when exposed to FLC

    Étude et analyse statistique de potentiels Ă©voquĂ©s auditifs sous l'influence de radiofrĂ©quences

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    Ce papier traite de l'étude de l'influence des champs radioélectriques émis par les téléphones portables sur l'activité cérébrale humaine. Notre travail est réalisé sur le systÚme auditif à partir du recueil de Potentiels Evoqués Auditifs (PEA) à la surface du scalp. Le protocole permet de comparer les PEA enregistrés avec ou sans exposition aux radiofréquences. Les stimuli sont deux sons purs et un systÚme permet de contrÎler la puissance des radiofréquences émises. Pour obtenir une référence et tenir compte de la fatigue, l'effet placebo est également considéré. Notre étude consiste à mettre en oeuvre des mesures fiables qui soient révélatrices de certains changements ou de certaines constances dans les signaux enregistrés. Elles concernent ici les corrélations calculées entre signaux moyens, les amplitudes de l'onde N100, ainsi que les corrélations entre ces amplitudes. La comparaison des corrélations calculées entre signaux recueillis avec et sans exposition aux radiofréquences fait apparaßtre une différence. Un point important de cette étude concerne le rÎle de l'effet de fatigue dans l'analyse des PEA

    Epileptic networks in focal cortical dysplasia revealed using electroencephalography-functional magnetic resonance imaging.

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    Surgical treatment of focal epilepsy in patients with focal cortical dysplasia (FCD) is most successful if all epileptogenic tissue is resected. This may not be evident on structural magnetic resonance imaging (MRI), so intracranial electroencephalography (icEEG) is needed to delineate the seizure onset zone (SOZ). EEG-functional MRI (fMRI) can reveal interictal discharge (IED)-related hemodynamic changes in the irritative zone (IZ). We assessed the value of EEG-fMRI in patients with FCD-associated focal epilepsy by examining the relationship between IED-related hemodynamic changes, icEEG findings, and postoperative outcome
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