Le Pacifique de 5000 à 2000 avant le présent : suppléments à l'histoire d'une colonisation = The Pacific from 5000 to 2000 BP : colonisation and transformations

La colonisation préhistorique de l'Océanie a provoqué l'extinction de plusieurs milliers de populations et d'espèces entières d'oiseaux. A l'échelle de l'espèce, c'est l'extinction la plus grande jamais attestée par les collections de vertébrés fossiles. Il n'y a pratiquement aucune preuve d'extinction d'espèces d'oiseaux en Océanie avant l'arrivée de l'homme. Nous ne savons pas, cependant, si l'extinction des espèces indigènes a eu lieu en quelques années, décennies, siècles ou millénaires après la colonisation initiale par l'homme d'îles précédemment vierges. Trois séries de facteurs corrélés (physique intrinsèque, biologique intrinsèque et humain) influencent la vitesse et l'ampleur de l'extinction dans une île donnée. Tenant compte de ces facteurs, j'examine une série de données préliminaires provenant de sites Lapita de l'archipel de Ha'apai à Tonga qui suggère que l'extinction de la plupart des espèces d'oiseaux a eu lieu dans ces îles en quelques siècles et peut donc être qualifiée d'extinction catastrophique ou explosive. (Résumé d'auteur

The phonetics of Wa

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN026405 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

‘Weihing’ Great Northern Disease-resistant Dry Bean

Nebraska is the leading provider in the United States of Great Northern (GN) dry beans (Phaseolus vulgaris L.). Rust [(Uromyces appendiculatus (Pers.) Unger], common bacterial blight [(Xanthomonas campestris pv. phaseoli (Smith) Dye] (Xcp), and white mold [Sclerotinia sclerotiorum (Lib.) de Bary] diseases cause serious reductions in bean yield and seed quality in Nebraska. Halo blight (Pseudomonas syringae pv. syringae van Hall) has been observed in some years, but is not considered a major problem. Diseaseresistant cultivars should ensure improved seed yields and yield stability, and seed quality, and reduce pesticide application. Upright growth habit, combined with a porous plant canopy, can provide an avoidance mechanism to reduce white mold by improving air circulation, resulting in rapid drying of dew on the foliage (Deshpande et al., 1995). An adapted, highyielding Great Northern cultivar with resistance to strains of the above bacterial and rust pathogens prevailing in Nebraska is needed. An architectural avoidance of white mold is also required because there is no high level of physiological resistance in common beans to that pathogen. Presently, there is no Great Northern variety with this combination of desirable traits. The Great Northern ‘Weihing’ cultivar released in 1998 has the above combination of traits, and should reduce production costs. Origin ‘Weihing’ was derived from intercrosses of advanced lines developed from crosses of adapted and exotic dry bean parents possessing desired traits (Fig. 1). Pedigree selection was used to develop near-homozygous lines for intercrossing cycles. The advanced lines used for intercrossing possessed resistance to rust and levels of resistance to common bacterial blight and halo blight, as well as some avoidance of white mold disease because of upright and more open architecture. Multiple parents were used in the crosses. GN Nebr. #1 sel. 27 was a source of resistance to common blight and halo blight (Coyne and Schuster, 1974). ‘Tacaragua’ (black bean) (source: N.E. Valladares-Sanchez, Universidad de Oriente, Jusepin, Venezuela), ‘Aurora’ (small white), and Pinto 12689 (source: D. Wood, Colorado State Univ., Fort Collins, Colo.) provided resistance to rust. Pinto ‘UI 111’ and GN ‘1140’ contributed genes for earliness. GN ‘Emerson’ and ‘Bulgarian White’ possessed bright white seedcoats (Korban et al., 1981a), and were resistant to seedcoat cracking (Korban et al., 1981b). The upright and porous plant habit of ‘Tacaragua’, ‘Aurora’ (Anderson et al., 1974), and lines A222 and A51-1 [Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia] provided some architectural avoidance to the white mold pathogen. Fuller et al. (1984), using plastic-covered ground beds in greenhouse tests, also found that ‘Tacaragua’ had partial resistance to white mold

Implantation of a polycaprolactone scaffold with subchondral bone anchoring ameliorates nodules formation and other tissue alterations

PURPOSE: Articular cartilage has limited repair capacity. Two different implant devices for articular cartilage regeneration were tested in vivo in a sheep model to evaluate the effect of subchondral bone anchoring for tissue repair. METHODS: The implants were placed with press-fit technique in a cartilage defect after microfracture surgery in the femoral condyle of the knee joint of the sheep and histologic and mechanical evaluation was done 4.5 months later. The first group consisted of a biodegradable polycaprolactone (PCL) scaffold with double porosity. The second test group consisted of a PCL scaffold attached to a poly(L-lactic acid) (PLLA) pin anchored to the subchondral bone. RESULTS: For both groups most of the defects (75%) showed an articular surface that was completely or almost completely repaired with a neotissue. Nevertheless, the surface had a rougher appearance than controls and the repair tissue was immature. In the trials with solely scaffold implantation, severe subchondral bone alterations were seen with many large nodular formations. These alterations were ameliorated when implanting the scaffold with a subchondral bone anchoring pin. DISCUSSIONS: The results show that tissue repair is improved by implanting a PCL scaffold compared to solely microfracture surgery, and most importantly, that subchondral bone alterations, normally seen after microfracture surgery, were partially prevented when implanting the PCL scaffold with a fixation system to the subchondral bone.This work was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2013-46467-C4-R (including the FEDER financial support). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008–2011, Iniciativa Ingenio 2010, Consolider Program. CIBER actions are financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund