Regime shifts of Mediterranean forest carbon uptake and reduced resilience driven by multidecadal ocean surface temperatures.

The mechanisms translating global circulation changes into rapid abrupt shifts in forest carbon capture in semi-arid biomes remain poorly understood. Here, we report unprecedented multidecadal shifts in forest carbon uptake in semi-arid Mediterranean pine forests in Spain over 1950-2012. The averaged carbon sink reduction varies between 31% and 37%, and reaches values in the range of 50% in the most affected forest stands. Regime shifts in forest carbon uptake are associated with climatic early warning signals, decreased forest regional synchrony and reduced long-term carbon sink resilience. We identify the mechanisms linked to ocean multidecadal variability that shape regime shifts in carbon capture. First, we show that low-frequency variations of the surface temperature of the Atlantic Ocean induce shifts in the non-stationary effects of El Niño Southern Oscillation (ENSO) on regional forest carbon capture. Modelling evidence supports that the non-stationary effects of ENSO can be propagated from tropical areas to semi-arid Mediterranean biomes through atmospheric wave trains. Second, decadal changes in the Atlantic Multidecadal Oscillation (AMO) significantly alter sea-air heat exchanges, modifying in turn ocean vapour transport over land and land surface temperatures, and promoting sustained drought conditions in spring and summer that reduce forest carbon uptake. Third, we show that lagged effects of AMO on the winter North Atlantic Oscillation also contribute to the maintenance of long-term droughts. Finally, we show that the reported strong, negative effects of ocean surface temperature (AMO) on forest carbon uptake in the last decades are unprecedented over the last 150 years. Our results provide new, unreported explanations for carbon uptake shifts in these drought-prone forests and review the expected impacts of global warming on the profiled mechanisms.

Perioperative intense pulsed light to prevent and improve symptoms of post-laser corneal refractive surgery dry eye. A randomized clinical trial.

PURPOSE: To evaluate the efficacy of perioperative IPL therapy in preventing postoperative ocular surface disorders in patients undergoing corneal laser refractive surgery. DESIGN: randomized, controlled, clinical trial with triple-blinding. METHODS: Setting: Vissum Miranza - Alicante; Study population: 61 patients randomized in two groups: 31 study patients (perioperative IPL + laser refractive surgery) and 30 control patients (perioperative placebo + laser refractive surgery). Follow-up was conducted over a 6-month period; Intervention: Each participants underwent three IPL sessions with a two-week interval between each session (pre-surgery, post-surgery week-one, and post-surgery week-three). For controls, placebo was administered following the same protocol. MAIN OUTCOMES MEASURES: visual outcomes and refraction, slit-lamp examination, corneal topography, visual analogue scale questionnaire and Oculus Keratograph 5 M including tear meniscus height, non-invasive tear break- up time, ocular redness, infrared meibography and Ocular Surface Disease Index (OSDI) questionnaire. RESULTS: 61 randomized eyes were included. No significant differences were observed in terms of uncorrected and corrected distance visual acuity (UDVA, CDVA), refractive error or corneal aberrations. A statistically significant improvement in OSDI score (change -8.47, p = 0.043), tear meniscus (change 0.05 mm, p = 0.004) and Meibography (change -0.42, p = 0.012) was observed at the third postoperative month in the study group. Additionally, at the sixth postoperative month, there were statistically significant improvements in tear meniscus (change 0.06 mm, p = 0.018), tear break-up-time (change 1.68 s, p = 0.039) and Meibography (change -0.37, p = 0.030). CONCLUSIONS: Results suggest that perioperative IPL therapy applied to laser corneal refractive surgery improves objective and subjective ocular surface parameters over non-IPL-treated control patients and early postoperative dry eye symptoms.

Optical sensors for operando stress monitoring in lithium-based batteries containing solid-state or liquid electrolytes.

The study of chemo-mechanical stress taking place in the electrodes of a battery during cycling is of paramount importance to extend the lifetime of the device. This aspect is particularly relevant for all-solid-state batteries where the stress can be transmitted across the device due to the stiff nature of the solid electrolyte. However, stress monitoring generally relies on sensors located outside of the battery, therefore providing information only at device level and failing to detect local changes. Here, we report a method to investigate the chemo-mechanical stress occurring at both positive and negative electrodes and at the electrode/electrolyte interface during battery operation. To such effect, optical fiber Bragg grating sensors were embedded inside coin and Swagelok cells containing either liquid or solid-state electrolyte. The optical signal was monitored during battery cycling, further translated into stress and correlated with the voltage profile. This work proposes an operando technique for stress monitoring with potential use in cell diagnosis and battery design.