Centre de Recherches Interdisciplinaires en Histoire, Histoire de l'Art et Musicologie

Abstract Introduction Diagnostic relevance of plasma amyloid β (Aβ) for Alzheimer's disease (AD) process yields conflicting results. The objective of the study was to assess plasma levels of Aβ 42 and Aβ 40 in amnestic mild cognitive impairment (MCI), nonamnestic MCI, and AD patients and to investigate relationships between peripheral and central biomarkers. Methods One thousand forty participants (417 amnestic MCI, 122 nonamnestic MCI, and 501 AD) from the Biomarker of AmyLoïd pepTide and AlZheimer's diseAse Risk multicenter prospective study with cognition, plasma, cerebrospinal fluid (CSF), and magnetic resonance imaging assessments were included. Results Plasma Aβ 1–42 and Aβ 1–40 were lower in AD (36.9 [11.7] and 263 [80] pg/mL) than in amnestic MCI (38.2 [11.9] and 269 [68] pg/mL) than in nonamnestic MCI (39.7 [10.5] and 272 [52] pg/mL), respectively ( P = .01 for overall difference between groups for Aβ 1–42 and P = .04 for Aβ 1–40 ). Globally, plasma Aβ 1–42 correlated with age, Mini–Mental State Examination, and APOE ε4 allele. Plasma Aβ 1–42 correlated with all CSF biomarkers in MCI but only with CSF Aβ 42 in AD. Discussion Plasma Aβ was associated with cognitive status and CSF biomarkers, suggesting the interest of plasma amyloid biomarkers for diagnosis purpose.

Fires have played an important role in creating and maintaining savannas over the centuries and are also one of the main natural disturbances in forests. The functional role of fires in savannas and forests can be investigated through examining sedimentary charcoal in order to reconstruct long-term fire history. However, the relationship between charcoal and vegetation structure in tropical grassy ecosystems remains to be elucidated. Here, we compared recent charcoal records from lake sediments in three tropical ecosystems (forest, savanna, and forest–savanna mosaic) with land cover inferred from remote-sensing images. Charcoal width-to-length (W/L) ratio is a good proxy for changes in fuel type. At one of the lakes, a significant W/L modification from values >0.5 (mainly wood) to <0.5 (~grass) was recorded simultaneously with changes in land cover. Indeed, a significant deforestation was recorded around this lake in the remote-sensing imagery between 1984 and 1994. The results also indicate that a riparian forest around a lake could act as a physical filter for charcoal accumulation; we used the mean charcoal size as a proxy to evaluate this process. Charcoal Accumulation Rates (CHAR), a burned biomass proxy, were combined with W/L ratio and the mean charcoal size to investigate the land-use history of the landscapes surrounding the study sites. This combined approach allowed us to distinguish between episodic slash-and-burn practices in the forest and managed fields or pastures burning frequently.

Two Endangered primate taxa, the Tana River red colobus (population estimate less than 1200) and the Tana River mangabey (population estimate less than 2000), are only known from a restricted area of patchy riverine forest in the floodplain of the Lower Tana River in Kenya. This paper describes the discovery of several groups of both species further south, in the Tana Delta, which for the Tana River red colobus represents a marginal extension of its range, and for the Tana River mangabey a substantial extension of the known range. Both the extent and the quality of their previously known habitat continue to decline and the newly discovered sites are under severe threat from forest over-exploitation, attempts to redirect the river course away from the forest patches, expansion of large-scale irrigation both locally and upstream for food and for biofuel production which may affect river flows, and especially by the planned construction of a very large hydropower dam several hundred km upstream at Grand Falls. This sixth dam in the Tana River cascade may put an end to the natural flooding regime that has sustained the riverine forest where the primates reside. In fact, unless the new dam is designed and used to produce large managed flood releases that mimic the natural flooding regime, the entire high biodiversity floodplain and delta, its ecosystems, and the livelihoods dependent on them are in jeopardy. Locally, there is a need to come up with a common vision for the future of the delta and to implement proposed conservation measures.

In the last decade, the myth of the pristine tropical forest has been seriously challenged. In central Africa, there is a growing body of evidence for past human settlements along the Atlantic forests, but very little information is available about human activities further inland. Therefore, this study aimed at determining the temporal and spatial patterns of human activities in an archaeologically unexplored area of 110,000 km 2 located in the northern Congo Basin and currently covered by dense forest. Fieldwork involving archaeology as well as archaeobotany was undertaken in 36 sites located in southeastern Cameroon and in the northern Republic of Congo. Evidence of past human activities through either artifacts or charred botanical remains was observed in all excavated test pits across the study area. The set of 43 radiocarbon dates extending from 15,000 BP to the present time showed a bimodal distribution in the Late Holocene, which was interpreted as two phases of human expansion with an intermediate phase of depopulation. The 2300–1300 BP phase is correlated with the migrations of supposed farming populations from northwestern Cameroon. Between 1300 and 670 BP, less material could be dated. This is in agreement with the population collapse already reported for central Africa. Following this, the 670–20 BP phase corresponds to a new period of human expansion known as the Late Iron Age. These results bring new and extensive evidence of human activities in the northern Congo Basin and support the established chronology for human history in central Africa.

Abstract. Natural disturbances are the dominant form of forest regeneration and dynamics in unmanaged tropical forests. Monitoring the size distribution of treefall gaps is important to better understand and predict the carbon budget in response to land use and other global changes. In this study, we model the size frequency distribution of natural canopy gaps with a discrete power law distribution. We use a Bayesian framework to introduce and test, using Monte Carlo Markov chain and Kuo–Mallick algorithms, the effect of local physical environment on gap size distribution. We apply our methodological framework to an original light detecting and ranging dataset in which natural forest gaps were delineated over 30 000 ha of unmanaged forest. We highlight strong links between gap size distribution and environment, primarily hydrological conditions and topography, with large gaps being more frequent on floodplains and in wind-exposed areas. In the future, we plan to apply our methodological framework on a larger scale using satellite data. Additionally, although gap size distribution variation is clearly under environmental control, variation in gap size distribution in time should be tested against climate variability.

Alors que Bingu wa Mutharika a été reconduit à la présidence du Malawi, la multiplication des candidatures indépendantes lors des scrutins présidentiel et législatifs de mai 2009 a semblé remettre en cause le rôle d’intermédiaire obligé joué par les partis politiques dans la compétition électorale. Au prix d’un travail parfois contradictoire, ces derniers ont néanmoins réussi à opérer une clôture du champ électoral : étroitement liées aux partis dans leur genèse, les candidatures indépendantes connaissent en effet une carrière fortement déterminée par leur capacité à se référer au modèle partisan.

Abstract Introduction Blood‐based biomarkers are the next challenge for Alzheimer's disease (AD) diagnosis and prognosis. Methods Mild cognitive impairment (MCI) participants (N = 485) of the BALTAZAR study, a large‐scale longitudinal multicenter cohort, were followed‐up for 3 years. A total of 165 of them converted to dementia (95% AD). Associations of conversion and plasma amyloid beta (Aβ) 1‐42 , Aβ 1‐40 , Aβ 1‐42 /Aβ 1‐40 ratio were analyzed with logistic and Cox models. Results Converters to dementia had lower level of plasma Aβ 1‐42 (37.1 pg/mL [12.5] vs. 39.2 [11.1] , P value = .03) and lower Aβ 1‐42 /Aβ 1‐40 ratio than non‐converters (0.148 [0.125] vs. 0.154 [0.076], P value = .02). MCI participants in the highest quartile of Aβ 1‐42 /Aβ 1‐40 ratio (>0.169) had a significant lower risk of conversion (hazard ratio adjusted for age, sex, education, apolipoprotein E ε4, hippocampus atrophy = 0.52 (95% confidence interval [0.31–0.86], P value = .01). Discussion In this large cohort of MCI subjects we identified a threshold for plasma Aβ 1‐42 /Aβ 1‐40 ratio that may detect patients with a low risk of conversion to dementia within 3 years.

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Na atualidade, as sociedades tradicionais da Amazônia experimentam fortes mudanças com efeitos diretos sobre os sistemas agrícolas tradicionais, como a tendência à homogeneização de espécies e técnicas juntamente com uma dependência maior do mercado. Porém, as agriculturas amazônicas continuam diversificadas e valorizando a diversidade. O artigo descreve particularidades da agricultura Mebêngôkre-Kayapó a partir de uma metodologia elaborada com ferramentas da antropologia, da geografia e da etnobotânica em aldeias indígenas do sul do Pará. O manejo atual da agrobiodiversidade é analisado por meio da organização das roças no espaço e no tempo, e a partir de levantamentos realizados com foco na diversidade em nível de espécies e variedades de cultivos. Os resultados mostram que um grande número de plantas continua sendo cultivado e confirmam a vitalidade dos conhecimentos indígenas associados à agrobiodiversidade, mesmo em tempos de forte mudança. Os princípios de repartição, conservação, reprodução e fabricação da biodiversidade Mebêngôkre estão associados ao conceito de 'beleza' (mex), que valoriza, muito além de paisagens e técnicas agrícolas, o bom estado das redes sociais de trocas dentro e fora da aldeia, assim como valores essenciais dos Mebêngôkre.

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Understanding the patterns and processes underlying the heterogeneous distribution of traditional ecological knowledge (TEK) across communities of natural resource users is a growing research topic. However, social organization as a factor potentially shaping TEK intracultural distribution has received scant attention. Here, we analyze the role played by kinship groups—namely, patrilineal lineages and segments—in shaping bodies of TEK among a group of seminomadic pastoralists in India. We use two quantitative approaches (score based and similarity based) to analyze variations in four TEK domains: soils, ethnoveterinary, breeds, and ethnobotany. We find that kinship groups share divergent bodies of knowledge, a finding that we interpret in light of the social organization of migration, in which kinship provides a privileged basis that structures migratory groups and, as such, favors the constitution of shared bodies of knowledge. We conclude by advocating for a better inclusion of the organizational features that structure the collective life of local communities in research aiming at understanding TEK dynamics.

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Das Buch begibt sich auf die Suche nach dem verlorenen Reich des karolingischen Königs Lothar II., das 855 als »Lotharingien« eingerichtet wurde und bis zu seiner Auflösung im 10. Jahrhundert vielfache Veränderungen erfuhr. Stellte dieses politische Gebilde von der Nordsee bis zum Alpenrand einen kohärenten Raum mit einem für den Historiker fassbaren »Wir-Gefühl« dar? Die Studie beschäftigt sich umfassend mit diesen lotharingischen Gebieten und betrachtet sie aus institutioneller, ökonomischer, gesellschaftlicher und kultureller Perspektive. Die Auswertung wichtiger volkssprachiger Texte wie etwa des Ludwigslieds erlaubt eine Dekonstruktion der Vorstellung von einer lotharingischen Identität. Lotharingien erscheint damit als europäischer Erinnerungsort

Résumé En Amazonie, le développement des mobilités urbain-rural soulève la question des liens entre territorialités et gestion des ressources. Avec l’exemple de la région de Cruzeiro do Sul (Acre, Brésil), nous montrons que les échanges de plantes cultivées entre les agriculteurs constituent un vecteur de l’appropriation de l’espace, de l’entretien de la mémoire familiale et de la continuité géographique entre les lieux de vie. Les réseaux d’échanges reflètent des dynamiques de fixation collective et de mobilité individuelle sur le front pionnier. Ils témoignent de la gestion collective de ressources biologiques dans des espaces marqués par l’appropriation privée des moyens de production.

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The West Digital Conservatory of Archaeological Heritage project, a.k.a. WDCAH, is a new French research organization whose aim is to both ensure the preservation of digital archaeological data, and deliver expertise in production, analysis, visualization and virtual reality exploration techniques. This project is an interdisciplinary project composed of engineers and researchers in archaeology, computer science, virtual reality and 3D interaction with virtual environments. The major objectives of this conservatory project are: (i) sustainable and centralized safeguarding and archiving of 2D/3D data produced by the archaeological community; (ii) free access to metadata; (iii) secure access to data for the different actors involved in scientific projects and (iv) the support and advice for these actors in the 3D data production and exploration through the latest digital technologies, modeling tools and virtual reality systems. This paper focuses on the first activities of the WDCAH which mainly concern digital models production using photogrammetry, 3D laser scans, and 3D computer graphics software. We are currently working on the reconstitution of six archaeological sites located in the west of France ranging from prehistory to the Middle Ages: the Cairn of Carn Island, the covered pathway of Roh Coh Coet, the Goh Min Ru megalithic site, the gallo-roman mansion of Vanesia, the keep of the Château de Sainte-Suzanne, the Porte des Champs of the Château d'Angers. Other proposals are currently under study.