Uncertainties in the adaptation of alpine pastures to climate change based on remote sensing products and modelling.

Over the last century, the management of pastoral systems has undergone major changes to meet the livelihood needs of alpine communities. Faced with the changes induced by recent global warming, the ecological status of many pastoral systems has seriously deteriorated in the western alpine region. We assessed changes in pasture dynamics by integrating information from remote-sensing products and two process-based models, i.e. the grassland-specific, biogeochemical growth model PaSim and the generic crop-growth model DayCent. Meteorological observations and satellite-derived Normalised Difference Vegetation Index (NDVI) trajectories of three pasture macro-types (high, medium and low productivity classes) in two study areas - Parc National des Écrins (PNE) in France and Parco Nazionale Gran Paradiso (PNGP) in Italy - were used as a basis for the model calibration work. The performance of the models was satisfactory in reproducing pasture production dynamics (R2 = 0.52 to 0.83). Projected changes in alpine pastures due to climate-change impacts and adaptation strategies indicate that: i) the length of the growing season is expected to increase between 15 and 40 days, resulting in changes in the timing and amount of biomass production, ii) summer water stress could limit pasture productivity; iii) earlier onset of grazing could enhance pasture productivity; iv) higher livestock densities could increase the rate of biomass regrowth, but major uncertainties in modelling processes need to be considered; and v) the carbon sequestration potential of pastures could decrease under limited water availability and warming.

Detection of HCV RNA in serum and seminal fluid from HIV-1 co-infected intravenous drug addicts.

The presence of hepatitis C virus (HCV) RNA in serum and seminal fluid was investigated in eleven drug addicts coinfected with HIV-1 and HCV. Serum and seminal fluid were taken from each patient at the same time point. HCV RNA was found in ten of the eleven serum samples tested, but only in one of the semen samples. No relationship was observed between CD4 cell counts, the stage of HIV infection, extent of liver damage and the presence of HCV RNA in serum and semen. The results indicate that HCV is not usually present in the semen and provide further evidence against sexual transmission as an important mode of transmission of HCV infection.