Leaf area index (LAI) estimates can inform decision-making in crop management. The European Space Agency’s Sentinel-2 satellite, with observations in the red-edge spectral region, can monitor crops ...globally at sub-field spatial resolutions (10–20 m). However, satellite LAI estimates require calibration with ground measurements. Calibration is challenged by spatial heterogeneity and scale mismatches between field and satellite measurements. Unmanned Aerial Vehicles (UAVs), generating high-resolution (cm-scale) LAI estimates, provide intermediary observations that we use here to characterise uncertainty and reduce spatial scaling discrepancies between Sentinel-2 observations and field surveys. We use a novel UAV multispectral sensor that matches Sentinel-2 spectral bands, flown in conjunction with LAI ground measurements. UAV and field surveys were conducted on multiple dates—coinciding with different wheat growth stages—that corresponded to Sentinel-2 overpasses. We compared chlorophyll red-edge index (CIred-edge) maps, derived from the Sentinel-2 and UAV platforms. We used Gaussian processes regression machine learning to calibrate a UAV model for LAI, based on ground data. Using the UAV LAI, we evaluated a two-stage calibration approach for generating robust LAI estimates from Sentinel-2. The agreement between Sentinel-2 and UAV CIred-edge values increased with growth stage—R2 ranged from 0.32 (stem elongation) to 0.75 (milk development). The CIred-edge variance between the two platforms was more comparable later in the growing season due to a more homogeneous and closed wheat canopy. The single-stage Sentinel-2 LAI calibration (i.e., direct calibration from ground measurements) performed poorly (mean R2 = 0.29, mean NRMSE = 17%) when compared to the two-stage calibration using the UAV data (mean R2 = 0.88, mean NRMSE = 8%). The two-stage approach reduced both errors and biases by >50%. By upscaling ground measurements and providing more representative model training samples, UAV observations provide an effective and viable means of enhancing Sentinel-2 wheat LAI retrievals. We anticipate that our UAV calibration approach to resolving spatial heterogeneity would enhance the retrieval accuracy of LAI and additional biophysical variables for other arable crop types and a broader range of vegetation cover types.
The third-generation MitraClip NTR/XTR transcatheter edge-to-edge repair system was introduced to assist in leaflet grasping with the longer clip arms of MitraClip XTR and to improve ease of use with ...the modified delivery catheter.
The EXPAND study evaluated contemporary real-world outcomes in subjects with mitral regurgitation (MR) treated with the third-generation MitraClip NTR/XTR transcatheter edge-to-edge repair system.
EXPAND is a prospective, multicenter, international, single-arm study that enrolled patients with primary MR and secondary MR at 57 centers. Follow-up was conducted through 12 months. Echocardiograms were analyzed by an echocardiographic core laboratories. Study outcomes included: MR severity, functional capacity measured by New York Heart Association functional class, quality of life measured by Kansas City Cardiomyopathy Questionnaire, heart failure hospitalizations, all-cause mortality.
1,041 patients were enrolled from April 2018 through March 2019, of which 50.5% had primary or mixed etiology. Implant success was 98.9%; 1.5 ± 0.6 clips were implanted per subject. Significant MR reduction from baseline (≥MR 3+: 56.0%) to 30 days (≤MR 1+:88.8%) was maintained through 1 year (MR ≤1+: 89.2%). A total of 84.5% and 93.0% of subjects in primary MR and secondary MR, respectively, had ≤1+ MR at 1 year. Significant improvements were observed in clinical outcomes (New York Heart Association functional class I/II in 80.3%, +21.6 improvement in Kansas City Cardiomyopathy Questionnaire score) at 1 year. All-cause mortality and heart failure hospitalizations at 1 year were 14.9% and 18.9%, respectively, which was significantly lower than previous studies.
The study demonstrates treatment with the third-generation system resulted in substantial reduction of MR in a contemporary real-world practice, compared with the results of earlier EVEREST and COAPT trials.(The MitraClip® EXPAND Study of the Next Generation of MitraClip® Devices EXPAND; NCT03502811)
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Female sex is associated with poorer outcomes after surgical aortic valve replacement (SAVR). Data on sex-specific differences after transcatheter aortic valve replacement (TAVR) are conflicting.
To ...examine sex-specific differences in patients undergoing TAVR in the PARTNER (Placement of Aortic Transcatheter Valves) trial.
Secondary analysis of the randomized and nonrandomized portions of the PARTNER trial. (ClinicalTrials.gov: NCT00530894).
25 hospitals in the United States, Canada, and Germany.
High-risk and inoperable patients (1220 women and 1339 men).
TAVR.
Demographic characteristics, cardiac and noncardiac comorbidities, mortality, stroke, rehospitalization, vascular complications, bleeding complications, and echocardiographic valve parameters.
At baseline, women had lower rates of hyperlipidemia, diabetes, smoking, and renal disease but higher Society of Thoracic Surgeons Predicted Risk of Mortality scores (11.9% vs. 11.1%; P < 0.001). After TAVR, women had more vascular complications (17.3% vs. 10.0%; difference, 7.29 percentage points 95% CI, 4.63 to 9.95 percentage points; P < 0.001) and major bleeding (10.5% vs. 7.7%; difference, 2.8 percentage points CI, 0.57 to 5.04 percentage points; P = 0.012) but less frequent moderate and severe paravalvular regurgitation (6.0% vs. 14.3%; difference, -8.3 percentage points CI, -11.7 to -5.0 percentage points; P < 0.001). At 30 days, the unadjusted all-cause mortality rate (6.5% vs. 5.9%; difference, 0.6 percentage point CI, -1.29 to 2.45 percentage points; P = 0.52) and stroke incidence (3.8% vs. 3.0%; difference, 0.8 percentage point CI, -0.62 to 2.19 percentage points; P = 0.28) were similar. At 1 year, all-cause mortality was significantly lower in women than in men (19.0% vs. 25.9%; hazard ratio, 0.72 CI, 0.61 to 0.85; P < 0.001).
Secondary analysis that included nonrandomized trial data.
Despite a higher incidence of vascular and bleeding complications, women having TAVR had lower mortality than men at 1 year. Thus, sex-specific risk in TAVR is the opposite of that in SAVR, for which female sex has been shown to be independently associated with an adverse prognosis.
Edwards Lifesciences.
The terrestrial carbon sink has significantly increased in the past decades, but the underlying mechanisms are still unclear. The current synthesis of process-based estimates of land and ocean sinks ...requires an additional sink of 0.6 PgC yr
in the last decade to explain the observed airborne fraction. A concurrent global fire decline was observed in association with tropical agriculture expansion and landscape fragmentation. Here we show that a decline of 0.2 ± 0.1 PgC yr
in fire emissions during 2008-2014 relative to 2001-2007 also induced an additional carbon sink enhancement of 0.4 ± 0.2 PgC yr
attributable to carbon cycle feedbacks, amounting to a combined sink increase comparable to the 0.6 PgC yr
budget imbalance. Our results suggest that the indirect effects of fire, in addition to the direct emissions, is an overlooked mechanism for explaining decadal-scale changes in the land carbon sink and highlight the importance of fire management in climate mitigation.
Del Nido (DN) cardioplegia solution provides a depolarized hyperkalemic arrest lasting up to 60 minutes, and the addition of lidocaine may limit intracellular calcium influx. Single-dose DN ...cardioplegia solution may offer an alternative myocardial protection strategy to multi-dose cold whole blood (WB) cardioplegia following acute myocardial infarction (AMI).
We retrospectively reviewed 88 consecutive patients with AMI undergoing coronary artery bypass (CABG) surgery with cardioplegic arrest between June 2010 to June 2012. Patients exclusively received WB (n = 40, June 2010-July 2011) or DN (n = 48, August 2011-June 2012) cardioplegia. Preoperative and postoperative data were retrospectively reviewed and compared using propensity scoring.
No significant difference in age, maximum preoperative serum troponin level, ejection fraction, and STS score was present between DN and WB. A single cardioplegia dose was given in 41 DN vs. 0 WB patients (p < 0.001), and retrograde cardioplegia was used 10 DN vs. 31 WB patients (p < 0.001). Mean cardiopulmonary bypass and cross clamp times were significantly shorter in the DN group versus WB group. Transfusion rate, length of stay, intra-aortic balloon pump requirement, post-operative inotropic support, and 30-day mortality was no different between groups. One patient in the WB group required a mechanical support due to profound cardiogenic shock.
DN cardioplegia may provide equivalent myocardial protection to existing cardioplegia without negative inotropic effects in the setting of acute myocardial infarction.
Mangrove forests are important coastal wetlands because of the ecosystem services they provide especially their carbon potential. Mangrove forests productivity in the Niger Delta are poorly ...quantified and at risk of loss from oil pollution, deforestation, and invasive species. Here, we report the most extensive stem girth survey yet of mangrove plots for stand and canopy structure in the Niger Delta, across tidal and disturbance gradients. We established twenty-five geo-referenced 0.25-ha plots across two estuarine basins. We estimated aboveground biomass (AGB) from established allometric equations based on stem surveys. Leaf area index (LAI) was recorded using hemispherical photos. We estimated a mean AGB of 83.7 Mg ha
–1
with an order of magnitude range, from 11 to 241 Mg ha
–1
. We found significantly higher plot biomass in close proximity to a protected site and tidal channels, and the lowest in the sites where urbanization and wood exploitation was actively taking place. The mean LAI was 1.45 and ranged fivefold from 0.46 to 2.41 and there was a significant positive correlation between AGB and LAI (
R
2
= 0.31). We divided the plots into two disturbance regimes and three nipa palm (
Nypa fruticans
) invasion levels. Lower stem diameter (5–15 cm) accounted for 70% of the total biomass in disturbed plots, while undisturbed regimes had a more even (∼25%) contribution of different diameter at breast height (DBH) size classes to AGB. Nipa palm invasion also showed a significant link to larger variations in LAI and the proportion of basal area removed from plots. We conclude that mangrove forest degradation and exploitation is removing larger stems (>15 cm DBH), preferentially from these mangroves forests and creates an avenue for nipa palm colonization. This research identifies opportunities to manage the utilization of mangrove resources and reduce any negative impact. Our data can be used with remote sensing to estimate biomass in the Niger Delta and the inclusion of soil, leaf properties and demographic rates can analyze mangrove-nipa competition in the region.
The large-scale loss of Amazonian rainforest under some future climate scenarios has generally been considered to be driven by increased drying over Amazonia predicted by some general circulation ...models (GCMs). However, the importance of rainfall relative to other drivers has never been formally examined. Here, we conducted factorial simulations to ascertain the contributions of four environmental drivers (precipitation, temperature, humidity and CO₂) to simulated changes in Amazonian vegetation carbon (Cveg), in three dynamic global vegetation models (DGVMs) forced with climate data based on HadCM3 for four SRES scenarios. Increased temperature was found to be more important than precipitation reduction in causing losses of Amazonian Cveg in two DGVMs (Hyland and TRIFFID), and as important as precipitation reduction in a third DGVM (LPJ). Increases in plant respiration, direct declines in photosynthesis and increases in vapour pressure deficit (VPD) all contributed to reduce Cveg under high temperature, but the contribution of each mechanism varied greatly across models. Rising CO₂ mitigated much of the climate-driven biomass losses in the models. Additional work is required to constrain model behaviour with experimental data under conditions of high temperature and drought. Current models may be overly sensitive to long-term elevated temperatures as they do not account for physiological acclimation.
The long-term outcomes of transcatheter aortic valve replacement (TAVR) in inoperable patients with severe aortic stenosis remain unknown.
In the Placement of Aortic Transcatheter Valves (PARTNER) ...study, 358 patients were randomly assigned to TAVR or standard therapy. We report the 3-year outcomes on these patients, and the pooled outcomes for all randomly assigned inoperable patients (n=449) in PARTNER, as well, including the randomized portion of the continued access study (n=91). The 3-year mortality rate in the TAVR and standard therapy groups was 54.1% and 80.9%, respectively (P<0.001; hazard ratio, 0.53; 95% confidence interval, 0.41-0.68; P<0.001). In survivors, there was significant improvement in New York Heart Association functional class sustained at 3 years. The cumulative incidence of strokes at 3-year follow-up was 15.7% in TAVR patients versus 5.5% in patients undergoing standard therapy (hazard ratio, 2.81; 95% confidence interval, 1.26-6.26; P=0.012); however, the composite of death or strokes was significantly lower after TAVR versus standard therapy (57.4% versus 80.9%, P<0.001; hazard ratio, 0.60; 95% confidence interval, 0.46-0.77; P<0.001). Echocardiography showed a sustained increase in aortic valve area and decrease in transvalvular gradient after TAVR. Analysis of the 449 pooled randomly assigned patients (TAVR, n=220; standard therapy, n=229) demonstrated significant improvement in all-cause mortality and functional status during early and 3-year follow-up. The results of the pooled cohort were similar to the results obtained from the pivotal PARTNER trial.
TAVR resulted in better survival and functional status in inoperable patients with severe aortic stenosis with durable hemodynamic benefit on long-term follow-up. However, high residual mortality, even in successfully treated TAVR patients, highlights the need for more strategic patient selection.
http://www.clinicaltrials.gov. Unique identifier: NCT00530894.
Background and Aims
The immediate postischemic period is marked by elevated intracellular calcium levels, which can lead to irreversible myocyte injury. Del Nido cardioplegia was developed for use in ...the pediatric population to address the inability of immature myocardium to tolerate high levels of intracellular calcium following cardiac surgery. Our aim in this study is to determine if this solution can be used safely and effectively in an adult, reoperative population.
Methods
All patients undergoing isolated reoperative aortic valve replacement at our institution from 2010 to 2012 were retrospectively reviewed. Demographics, comorbidities, operative variables, postoperative complications, and patient outcomes were collected. Patients were divided into two groups based on cardioplegia strategy used: whole blood cardioplegia (WB, n = 61) and del Nido cardioplegia (DN, n = 52).
Results
Mean age in the study was 73.4 ± 14.3 years and 86 patients were male (76.1%). Eighty‐four patients had undergone prior coronary artery bypass graft (CABG) (74.3%). Patients in the DN group required significantly lower total volume of cardioplegia (1147.6 ± 447.2 mL DN vs. 1985.4 ± 691.1 mL WB, p < 0.001) and retrograde cardioplegia dose (279.3 ± 445.1 mL DN vs. 1341.2 ± 690.8 mL WB, p < 0.001). There were no differences in cross‐clamp time, bypass time, postoperative complication rate, or patient outcomes between groups.
Conclusions
Del Nido cardioplegia use in an adult, reoperative aortic valve population offers equivalent postoperative outcomes when compared with whole blood cardioplegia. In addition, use of del Nido solution requires lower total and retrograde cardioplegia volumes in order to achieve adequate myocardial protection. doi: 10.1111/jocs.12360 (J Card Surg 2014;29:445–449)
Considerable uncertainty surrounds the fate of Amazon rainforests in response to
climate change.
Here, carbon (C) flux predictions of five terrestrial biosphere models (Community
Land Model version ...3.5 (CLM3.5), Ecosystem Demography model version 2.1 (ED2),
Integrated BIosphere Simulator version 2.6.4 (IBIS), Joint UK Land Environment
Simulator version 2.1 (JULES) and Simple Biosphere model version 3 (SiB3)) and a
hydrodynamic terrestrial ecosystem model (the
Soil–Plant–Atmosphere (SPA) model) were evaluated against
measurements from two large-scale Amazon drought experiments.
Model predictions agreed with the observed C fluxes in the control plots of both
experiments, but poorly replicated the responses to the drought treatments. Most
notably, with the exception of ED2, the models predicted negligible reductions
in aboveground biomass in response to the drought treatments, which was in
contrast to an observed c. 20% reduction at both sites.
For ED2, the timing of the decline in aboveground biomass was accurate, but the
magnitude was too high for one site and too low for the other.
Three key findings indicate critical areas for future research and model
development. First, the models predicted declines in autotrophic respiration
under prolonged drought in contrast to measured increases at one of the sites.
Secondly, models lacking a phenological response to drought introduced bias in
the sensitivity of canopy productivity and respiration to drought. Thirdly, the
phenomenological water-stress functions used by the terrestrial biosphere models
to represent the effects of soil moisture on stomatal conductance yielded
unrealistic diurnal and seasonal responses to drought.
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