Potential impacts of climate change on the productivity and soil carbon stocks of managed grasslands.

Rain-fed pastoral systems are tightly connected to meteorological conditions. It is, therefore, likely that climate change, including changing atmospheric CO2 concentration, temperature, precipitation and patterns of climate extremes, will greatly affect pastoral systems. However, exact impacts on the productivity and carbon dynamics of these systems are still poorly understood, particularly over longtime scales. The present study assesses the potential effects of future climatic conditions on productivity and soil organic carbon (SOC) stocks of mowed and rotationally grazed grasslands in France. We used the CenW ecosystem model to simulate carbon, water, and nitrogen cycles in response to changes in environmental drivers and management practices. We first evaluated model responses to individual changes in each key meteorological variable to get better insights into the role and importance of each individual variable. Then, we used 3 sets of meteorological variables corresponding to 3 Representative Concentration Pathways (RCP 2.6, RCP 4.5 and RCP 8.5) for long-term model runs from 1975 to 2100. Finally, we used the same three RCPs to analyze the responses of modelled grasslands to extreme climate events. We found that increasing temperature slightly increased grasslands productivities but strongly reduced SOC stocks. A reduction in precipitation led to reductions of biomass and milk production but increased SOC. Conversely, doubling CO2 concentration strongly increased biomass and milk production and marginally reduced SOC. These SOC trends were unexpected. They arose because both increasing precipitation and CO2 increased photosynthetic carbon gain, but they had an even greater effect on the proportion of biomass that could be grazed. The amount of carbon remaining on site and able to contribute to SOC formation was actually reduced under both higher precipitation and CO2. The simulations under the three RCPs indicated that grassland productivity was increased, but that required higher N fertilizer application rates and also led to substantial SOC losses. We thus conclude that, while milk productivity may continue at current rates under climate change, or even increase slightly, there could be some soil C losses over the 21st century. In addition, under the highest-emission scenario, the increasing importance of extreme climate conditions (heat waves and droughts) might render conditions at our site in some years as unsuitable for milk production. It highlights the importance of tailoring farming practices to achieve the dual goals of maintaining agricultural production while safeguarding soil C stocks.

Ranibizumab for exudative age-related macular degeneration: A five year study of adherence to follow-up in a real-life setting.

PURPOSE: To analyze adherence to follow-up over 5 years in patients treated with intravitreal ranibizumab for exudative age-related macular degeneration (AMD) in a tertiary health care center. To investigate factors associated with failure to continue follow-up. METHODS: Retrospective chart review of all consecutive patients with exudative AMD, who received their first intravitreal ranibizumab injection at the Créteil Intercommunal University Hospital Eye Clinic between October 1, 2006 and March 31, 2007. Patient clinical characteristics at baseline and at the last follow-up visit were recorded. Distance from home to hospital was measured for each patient. A multiple-choice telephone survey was conducted for patients lost to follow-up to determine the main reasons for failure to continue follow-up. RESULTS: Two hundred and one patients were included. The rate of loss to follow-up over the 5-year period was 57% (115/201). Fifty-eight patients lost to follow-up completed the questionnaire. The main reasons reported by patients for follow-up discontinuation were long distance from home to hospital (51.7%, 30/58), subjective dissatisfaction with the benefits of intravitreal injections (34.5%, 20/58), and the excessive burden of periodic follow-up visits (24.1%, 14/58). Three factors were significantly associated with follow-up discontinuation: high age at baseline (82.2 vs. 76.5 years, P<0.001), poor best-corrected visual acuity (BCVA) at baseline (42.5 vs. 51.0 letters, P=0.020), and long distance from home to hospital (132 vs. 17.1km, P<0.001). CONCLUSION: In this study, adherence to follow-up over 5 years was poor. Age and BCVA at baseline and distance from home to hospital were independently associated with long-term adherence.

High-resolution spectral domain optical coherence tomography features in adult onset foveomacular vitelliform dystrophy.

PURPOSE: To describe the different morphological features in adult onset foveomacular vittelliform dystrophy (AOFVD) using high-resolution spectral domain optical coherence tomography (OCT). DESIGN: Prospective observational case series. METHODS: Complete ophthalmologic examination, including spectral domain OCT, was performed in 49 consecutive AOFVD patients (60 eyes). RESULTS: In 28/60 eyes, spectral domain OCT showed hyper-reflective clumps within the outer plexiform and outer nuclear layers. In 9/60 eyes, the photoreceptor inner segment/outer segment (IS/OS) interface appeared highly reflective like a shell all around the vitelliform material, and appeared irregular and discontinued in 27/60 eyes. The Verhoeff membrane was clearly visible at the border of the lesion, disappeared over the vitelliform lesion in 20/60 eyes, became thickened and less defined on the outer aspect of the lesion in 11/60 eyes, appeared without noticeable alterations in 10/60 eyes and not well defined in 19/60 eyes. The vitelliform material appeared as a highly reflective dome-shaped lesion (homogeneous in 14/60 eyes and heterogeneous in 36/60 eyes) located between the photoreceptor layer and the retinal pigment epithelium (RPE). In 10/60 eyes, the macular lesion appeared as hypo/a-reflective. The RPE appeared irregular in 14/60 eyes, with hyper-reflective mottling on its inner aspect. We observed discrete RPE detachments in 29/60 eyes. CONCLUSIONS: We hypothesise that early changes involve the layer between RPE and the IS/OS interface, first with vitelliform material accumulation beneath the sensory retina, and then with IS/OS alterations, pigments migration towards inner layers and fluid accumulation. These changes come with RPE alterations such as hypertrophy or sub-RPE deposits.