Vegetation height products between 60° S and 60° N from ICESat GLAS data.

We present new coarse resolution (0.5� ×0.5�)vegetation height and vegetation-cover fraction data sets between 60� S and 60� N for use in climate models and ecological models. The data sets are derived from 2003–2009 measurements collected by the Geoscience Laser Altimeter System (GLAS) on the Ice, Cloud and land Elevation Satellite (ICESat), the only LiDAR instrument that provides close to global coverage. Initial vegetation height is calculated from GLAS data using a development of the model of Rosette et al. (2008) with further calibration on desert sites. Filters are developed to identify and eliminate spurious observations in the GLAS data, e.g. data that are affected by clouds, atmosphere and terrain and as such result in erroneous estimates of vegetation height or vegetation cover. Filtered GLAS vegetation height estimates are aggregated in histograms from 0 to 70m in 0.5m intervals for each 0.5�×0.5�. The GLAS vegetation height product is evaluated in four ways. Firstly, the Vegetation height data and data filters are evaluated using aircraft LiDAR measurements of the same for ten sites in the Americas, Europe, and Australia. Application of filters to the GLAS vegetation height estimates increases the correlation with aircraft data from r =0.33 to r =0.78, decreases the root-mean-square error by a factor 3 to about 6m (RMSE) or 4.5m (68% error distribution) and decreases the bias from 5.7m to −1.3 m. Secondly, the global aggregated GLAS vegetation height product is tested for sensitivity towards the choice of data quality filters; areas with frequent cloud cover and areas with steep terrain are the most sensitive to the choice of thresholds for the filters. The changes in height estimates by applying different filters are, for the main part, smaller than the overall uncertainty of 4.5–6m established from the site measurements. Thirdly, the GLAS global vegetation height product is compared with a global vegetation height product typically used in a climate model, a recent global tree height product, and a vegetation greenness product and is shown to produce realistic estimates of vegetation height. Finally, the GLAS bare soil cover fraction is compared globally with the MODIS bare soil fraction (r = 0.65) and with bare soil cover fraction estimates derived from AVHRR NDVI data (r =0.67); the GLAS treecover fraction is compared with the MODIS tree-cover fraction (r =0.79). The evaluation indicates that filters applied to the GLAS data are conservative and eliminate a large proportion of spurious data, while only in a minority of cases at the cost of removing reliable data as well. The new GLAS vegetation height product appears more realistic than previous data sets used in climate models and ecological models and hence should significantly improve simulations that involve the land surface

Improved global simulations of gross primary product based on a separate and explicit treatment of diffuse and direct sunlight

For computational expediency, regional and global land-surface models (LSMs), especially those coupled to climate simulations, adopt simple algorithms when calculating radiative transfer (RT) and canopy photosynthesis at the vegetated land surface. Nevertheless, the interaction of sunlight with vegetation is recognized as one of the most critical processes represented in LSMs. The present study calculates global, terrestrial Gross Primary Product (GPP) with a version of the land-surface model JULES which has been modified to take explicit account of sunfleck penetration and leaf orientation within the canopy. A comparison with equivalent simulations adopting the Big Leaf (BL) or two-stream (2ST) RT scheme, indicate that current regional/global LSMs may overestimate GPP by 10% globally and up to 25% regionally. Specifically, their use of average light profiles, and consequent neglect of the dispersion in leaf irradiance, at any given height in the canopy leads to both a general overestimation of canopy light-use efficiency (LUE) and a failure to capture the LUE-enhancement under diffuse sunlight (“diffuse fertilization effect”). We also examine the current limitations of regionally/globally implemented RT schemes with respect to canopy architecture. This is done by coupling JULES to the ray-tracing numerical model FLIGHT, the latter simulating light transfer and photosynthesis in both uniform one-dimensional (1-D) canopies and 3-D tree crowns. When the distribution of leaf nitrogen (N) is configured in a manner consistent with field measurements, output from the 3-D and 1-D FLIGHT simulations is fairly similar (predicted GPP differs by ≤5%). Similarly, both Leaf Angle Distribution (LAD), when restricted to its observed range, and leaf-clumping appear to have a minor influence over canopy productivity. We conclude that current LSMs can radically improve their calculation of regional/global GPP by adopting a multilayer approach. This will allow the separate treatment of sunlit and shaded foliage, at discrete heights within the canopy, as well as the accurate representation of active leaf-

Interactions between vegetation and climate: radiative and physiological effects of doubled atmospheric co2

The radiative and physiological effects of doubled atmospheric carbon dioxide (CO2) on climate are investigated using a coupled biosphere atmosphere model. Five 30-yr climate simulations, designed to assess the radiative and physiological effects of doubled CO2, were compared to a 30-yr control run. When the CO2 concentration was doubled for the vegetation physiological calculations only assuming no changes in vegetation biochemistry, the mean temperature increase over land was rather small (0.3 K) and was associated with a slight decrease in precipitation (20.3 percent). In a second case, the vegetation was assumed to have adapted its biochemistry to a doubled CO2 (2-3 CO2) atmosphere and this down regulation caused a 35 percent decrease in stomatal conductance and a 0.7-K increase in land surface temperature. The response of the terrestrial biosphere to radiative forcing alone that is, a conventional greenhouse warming effect revealed important interactions between the climate and the vegetation. Although the global mean photosynthesis exhibited no change, a slight stimulation was observed in the tropical regions, whereas in the northern latitudes photosynthesis and canopy conductance decreased as a result of high temperature stress during the growing season. This was associated with a temperature increase of more than 2 K greater in the northern latitudes than in the Tropics (4.0 K vs 1.7 K). These interactions also resulted in an asymmetry in the diurnal temperature cycle, especially in the Tropics where the nighttime temperature increase due to radiative forcing was about twice that of the daytime, an effect not discernible in the daily mean temperatures. The radiative forcing resulted in a mean temperature increase over land of 2.6 K and 7 percent increase in precipitation with the least effect in the Tropics. As the physiological effects were imposed along with the radiative effects, the overall temperature increase over land was 2.7 K but with a smaller difference (0.7 K) between the northern latitudes and the Tropics. The radiative forcing resulted in an increase in available energy at the earth's surface and, in the absence of physiological effects, the evapotranspiration increased. However, changes in the physiological control of evapotranspiration due to increased CO2 largely compensated for the radiative effects and reduced the evapotranspiration approximately to its control value

z Phase II Feasibility and Biomarker Study of Neoadjuvant Trastuzumab and Pertuzumab With Chemoradiotherapy for Resectable Human Epidermal Growth Factor Receptor 2-Positive Esophageal Adenocarcinoma: TRAP Study

PURPOSE Approximately 15% to 43% of esophageal adenocarcinomas (EACs) are human epidermal growth factor receptor 2 (HER2) positive. Because dual-agent HER2 blockade demonstrated a survival benefit in breast cancer, we conducted a phase II feasibility study of trastuzumab and pertuzumab added to neoadjuvant chemoradiotherapy (nCRT) in patients with EAC.PATIENTS AND METHODS Patients with resectable HER2-positive EAC received standard nCRT with carboplatin and paclitaxel and 41.4 Gy of radiotherapy, with 4 mg/kg of trastuzumab on day 1, 2 mg/kg per week during weeks 2 to 6, and 6 mg/kg per week during weeks 7, 10, and 13 and 840 mg of pertuzumab every 3 weeks. The primary end point was feasibility, defined as >= 80% completion of treatment with both trastuzumab and pertuzumab. An exploratory comparison of survival with a propensity score-matched cohort receiving standard nCRT was performed, as were exploratory pharmacokinetic and biomarker analyses.RESULTS Of the 40 enrolled patients (78% men; median age, 63 years), 33 (83%) completed treatment with trastuzumab and pertuzumab. No unexpected safety events were observed. R0 resection was achieved in all patients undergoing surgery, with pathologic complete response in 13 patients (34%). Three-year progression-free and overall survival (OS) were 57% and 71%, respectively (median follow-up, 32.1 months). Compared with the propensity score-matched cohort, a significantly longer OS was observed with HER2 blockade (hazard ratio, 0.58; 95% CI, 0.34 to 0.97). Results of pharmacokinetic analysis and activity on [F-18]fluorodeoxyglucose positron emission tomography scans did not correlate with survival or pathologic response. Patients with HER2 3+ overexpression or growth factor receptor-bound protein 7 (Grb7) -positive tumors at baseline demonstrated significantly better survival (P = .007) or treatment response (P = .016), respectively.CONCLUSION Addition of trastuzumab and pertuzumab to nCRT in patients with HER2-positive EAC is feasible and demonstrates potentially promising activity compared with historical controls. HER2 3+ overexpression and Grb7 positivity are potentially predictive for survival and treatment response, respectively. (C) 2019 by American Society of Clinical OncologyExperimentele farmacotherapi