Spatial heterogeneity of land cover response to climatic change in the Nilgiri highlands (southern India) since the Last Glacial Maximum

25 pagesFourteen hillslope soil profiles were sampled under natural vegetation (i.e., grassland or forest) and plantations in the Nilgiri highlands, southern India. Delta 13C ratios were measured at different depths and 14C ages determined for six profiles. In these highland soils where the turnover rate of organic matter is extremely low, the Δ13C ratios of entire soil profiles have recorded signatures of past land cover. By correlating the data with results previously obtained from peat bogs and with knowledge concerning the history of human settlement, we distinguish three contrasting trajectories of palaeoenvironmental history and landscape change since the Last Glacial Maximum. In the central Nilgiris, between 18 and 10 ka BP, forest expansion occurred due to the conjunction of a wetter climate (the maximum of southwest monsoon-related humidity occurring at ca. 11 ka BP) and higher temperatures; since 10 ka BP, the reversal towards grassland vegetation is attributed to drier conditions. In the western Nilgiris, where strong southwest monsoon winds permanently restrict forest patches to sheltered valley sites, steady but limited expansion of forest from 18 ka BP to the present is recorded and attributed to rising temperatures. The southern and eastern Nilgiris, where the northeast monsoon contributes 20% of the annual rainfall, are the less sensitive to fluctuations in the southwest monsoon. In these areas, rapid and extensive expansion of forest occurred mainly as a consequence of higher temperatures from 18 ka BP to the present. Massive deforestation by Badaga cultivators and Europeans planters followed after the 16th century AD. As a result, and in contrast with the western Nilgiris where the land cover mosaic has remained remarkably stable in the last 18 ka BP, the current landscape differs sharply from the land cover pattern detected by the soil record

Effet de différents systèmes de culture à couverture végétale sur le stockage du carbone dans un sol argileux des Hautes Terres de Madagascar

Stocker du carbone dans le sol permet d'améliorer ses propriétés physico-chimiques et de réduire les émissions de dioxyde de carbone vers l'atmosphère. L'effet des systèmes en semis direct avec couverture végétale (SCV) sur le stockage de C dans le sol est étudié sur un dispositif agronomique de longue durée (11 ans) à Antsirabe, Madagascar (16°C, 1 300 mm). Quatre systèmes sont étudiés: un système en labour conventionnel avec exportation des résidus de récolte [CT m/s, rotation maïs (Zea mays L.)-soja (Glycine max. L.)], et trois systèmes en SCV sans travail du sol, et avec restitution des résidus de récolte [NT m/s, rotation maïs-soja; NT m/m-d, rotation maïs-maïs avec une couverture végétale de Desmodium uncinatum; et NT h/s-k, rotation haricot (Phaseolus vulgaris)-soja avec une couverture végétale de Pennissetum clandestinum]. Le sol est très argileux, à faible capacité d'échange cationique mais possédant des propriétés andiques pouvant influencer les potentialités de stockage du C du sol. A 0-5 cm, les teneurs en C sont plus élevées sous SCV (NT m/s, NT m/m-d et NT his) que sous labour (CT m/s), et à 5-10 cm, elles sont plus élevées sous NT m/m-d et NT m/s que sous NT h/s-k et CT m/s. Le stockage annuel de C, à masse de sol équivalente, est de 0,69 et 1,01 mg C.ha-1.an-1, sous NT m/s et NT m/m-d pour l'horizon équivalent à 0-20 cm, alors qu'il n'y a pas d'effet SCV observé pour l'horizon équivalent à 0-40 cm. Ceci peut être dû à la fois à l'absence réelle de stockage comme à une variabilité initiale des teneurs en C dans les horizons de profondeurs, car le labour n'est effectué que jusqu'à 20 cm de profondeur. Les différences de stockage de C entre NT et CT dans la couche 0-20 cm sont essentiellement attribuées aux quantités beaucoup plus importantes de résidus organiques restituées par les systèmes NT par rapport au système labouré CT, mais on peut aussi envisager qu'une partie de cette différence soit le fait d'une perte de C par érosion sous labour. Les teneurs en macroagrégats stables (MA, 200-2 000 [mu]m) sont plus élevées sous NT m/s, NT h/s-k et NT m/m-d que sous CT m/s à 0-5 cm et à 5-10 cm. Cette teneur en MA est corrélée positivement (R = 0,408, p < 0,05, n = 24) avec la teneur en C du sol, ce qui pourrait induire (i) une amélioration de l'agrégation en fonction de l'augmentation de la teneur en C du sol et (ii) une protection du C se trouvant à l'intérieur de ces agrégats contre la minéralisation microbienne. Toutefois, la respirométrie ne montre pas une protection physique de C dans les sites de protection supérieurs à 200 [mu]m pour NT m/s et CT m/s. Dans cette étude, le C stocké dans le sol pourrait alors être protégé contre la minéralisation par d'autres processus comme l'adsorption sur les colloïdes du sol ou la recalcitrance biochimique de la matière organique du sol. (Résumé d'auteur

The Effectiveness of Support and Rehabilitation Services for Women Offenders

There is a large body of research evidence suggesting that support, rehabilitation, and supervision programs can help offenders to reduce recidivism. However, the effectiveness of these services is dependent upon the extent to which the workers who deliver them comply with "what works" principles and practices. Because most of this research has been conducted with men, this study focused on the extent to which these principles and practices apply to women. In particular, the study examined services offered to a group of women in prison in Victoria, Australia, and following their release to the community; and the relationship between these women's views about the services, recidivism, and the characteristics of the services. Results were generally consistent with earlier research. The women favoured services that are delivered by workers who are reliable, holistic, collaborative, who understand the women's perspective, and that focus on strengths. They did not support services that challenged the women, focused on their offences, or on the things they did badly

L'HYDROPTERE: HOW MULTIDISCIPLINARY SCIENTIFIC RESEARCH MAY HELP BREAK THE SAILING SPEED RECORD

In 2009, l’Hydroptère broke the symbolic barrier of 50 knots and became the world fastest sailing boat over both 500 meters and 1 nautical mile. This major achievement relied on the high skills of the sailing team but also on technical advances of the boat, resulting from the scientific collaboration between the Hydroptère Design Team and the Ecole Polytechnique Fédérale de Lausanne (EPFL). In the present article, we highlight the multidisciplinary research activity performed within EPFL in the course of this collaboration involving aero- and hydrodynamics, materials and structure as well as computer vision. Various foils were tested at reduced scale in a high speed water tunnel, and the results used to validate the numerical simulations. Composite materials, their processing parameters and assembly components were tested. The structural behaviour was also investigated to determine strains and stresses in normal and extreme sailing conditions, taking waves into account, and a combined model was derived for dynamic simulation. Finally, advanced computer vision methods were developed and implemented on the boat to monitor foil immersion and cross beams deformations

Differential Effects of Early- and Late-Life Access to Carotenoids on Adult Immune Function and Ornamentation in Mallard Ducks (Anas platyrhynchos)

Environmental conditions early in life can affect an organism’s phenotype at adulthood, which may be tuned to perform optimally in conditions that mimic those experienced during development (Environmental Matching hypothesis), or may be generally superior when conditions during development were of higher quality (Silver Spoon hypothesis). Here, we tested these hypotheses by examining how diet during development interacted with diet during adulthood to affect adult sexually selected ornamentation and immune function in male mallard ducks (Anas platyrhynchos). Mallards have yellow, carotenoid-pigmented beaks that are used in mate choice, and the degree of beak coloration has been linked to adult immune function. Using a 2×2 factorial experimental design, we reared mallards on diets containing either low or high levels of carotenoids (nutrients that cannot be synthesized de novo) throughout the period of growth, and then provided adults with one of these two diets while simultaneously quantifying beak coloration and response to a variety of immune challenges. We found that both developmental and adult carotenoid supplementation increased circulating carotenoid levels during dietary treatment, but that birds that received low-carotenoid diets during development maintained relatively higher circulating carotenoid levels during an adult immune challenge. Individuals that received low levels of carotenoids during development had larger phytohemagglutinin (PHA)-induced cutaneous immune responses at adulthood; however, dietary treatment during development and adulthood did not affect antibody response to a novel antigen, nitric oxide production, natural antibody levels, hemolytic capacity of the plasma, or beak coloration. However, beak coloration prior to immune challenges positively predicted PHA response, and strong PHA responses were correlated with losses in carotenoid-pigmented coloration. In sum, we did not find consistent support for either the Environmental Matching or Silver Spoon hypotheses. We then describe a new hypothesis that should be tested in future studies examining developmental plasticity

Cheek Tooth Morphology and Ancient Mitochondrial DNA of Late Pleistocene Horses from the Western Interior of North America: Implications for the Taxonomy of North American Late Pleistocene Equus

Horses were a dominant component of North American Pleistocene land mammal communities and their remains are well represented in the fossil record. Despite the abundant material available for study, there is still considerable disagreement over the number of species of Equus that inhabited the different regions of the continent and on their taxonomic nomenclature. In this study, we investigated cheek tooth morphology and ancient mtDNA of late Pleistocene Equus specimens from the Western Interior of North America, with the objective of clarifying the species that lived in this region prior to the end-Pleistocene extinction. Based on the morphological and molecular data analyzed, a caballine (Equus ferus) and a non-caballine (E. conversidens) species were identified from different localities across most of the Western Interior. A second non-caballine species (E. cedralensis) was recognized from southern localities based exclusively on the morphological analyses of the cheek teeth. Notably the separation into caballine and non-caballine species was observed in the Bayesian phylogenetic analysis of ancient mtDNA as well as in the geometric morphometric analyses of the upper and lower premolars. Teeth morphologically identified as E. conversidens that yielded ancient mtDNA fall within the New World stilt-legged clade recognized in previous studies and this is the name we apply to this group. Geographic variation in morphology in the caballine species is indicated by statistically different occlusal enamel patterns in the specimens from Bluefish Caves, Yukon Territory, relative to the specimens from the other geographic regions. Whether this represents ecomorphological variation and/or a certain degree of geographic and genetic isolation of these Arctic populations requires further study