Crop load regulation in modern apple fruit growing is an essential tool for obtaining regular and high quality yields. Common applied thinning products in Italy, such as naphthaleneacetic acid (NAA), ...naphtaleneacetamide (NAD), benzyladenine (BA), 2-chloroethylphosphonic acid (ethephon) and ammonium thiosulphate (ATS), do not always give satisfactory and consistent thinning results. Therefore, the interest farmers have in finding new thinning agents remains high. Within the present study, the impact of metamitron as a thinning compound was tested on 'Golden Delicious' CloneB Lb®, 'Golden Delicious' Reinders® and 'Fuji' KIKU®8 apple plants, in different open field trials. Results indicate that metamitron reduced fruit set in a concentration-dependent manner and highest abscission rates were encountered when thinning was conducted at 12 mm fruit diameter. Fruit drop increased generally in those plants, where leaf net photosynthesis was strongly inhibited by metamitron. At the same time, an increase in leaf chlorophyll fluorescence of photosystem I was detected. Maximum photosynthetic stress levels were recorded approximately 6 days after application, whereas a complete recovering occurred within 3-4 weeks. Fruit quality parameters such as fruit size, fruit color, soluble solid content, and titratable acidity were improved by metamitron. Fruit russeting remained unaltered, besides some leaf phytotoxic effects compared to treated plants. So far, only the poor return bloom remains a concern. To sum up, the present study shows that metamitron would represent a very promising and powerful tool for regulating apple crop load.
A comprehensive and reliable water balance of snow‐dominated alpine catchments is required for a holistic analysis of the hydrological and hydrogeological processes. A major limitation to the ...elaboration of this balance in alpine terrain is the difficulty of data acquisition as well as the limited presence of meteorological stations. Remotely sensed data can provide valuable information for the water balance assessment on a regional scale. We exploited Sentinel‐satellite data to estimate the groundwater storage for one hydrologic year in an extensive Alpine catchment located in northern Italy by means of the residual water balance approach. In particular, Evapotranspiration (ET) and Snow Water Equivalent were estimated with the combined use of Sentinel data, at a spatial resolution of 20 and 30 m, respectively. The results show that the adopted satellite‐based methods allow obtaining consistent and physically realistic values to describe the groundwater storage dynamics. In the period 2018–2020, a positive storage occurred only during the snowmelt period and the overall storage was negative, leading to a net lowering of the groundwater level in the floodplain. In addition, the influence of physiographic parameters (altitude, slope, and aspect) and seasonality on the estimates of ET and snow‐depth were investigated.
Key Points
A new methodology to quantify groundwater storage dynamics in snow‐dominated catchments by the residual water balance approach is presented
Hydrological components are estimated with a high temporal and spatial resolution by a novel approach based on synergistic use of Sentinel data
Results contribute to the understanding of hydrological processes in Alpine areas and the expected effects of climate change
Highly simplified approaches continue to underpin hydrological climate change impact assessments across the Earth's mountainous regions. Fully‐integrated surface‐subsurface models may hold far ...greater potential to represent the distinctive regimes of steep, geologically‐complex headwater catchments. However, their utility has not yet been tested across a wide range of mountainous settings. Here, an integrated model of two adjacent calcareous Alpine headwaters that accounts for two‐dimensional surface flow, three‐dimensional (3D) variably‐saturated groundwater flow, and evapotranspiration is presented. An energy balance‐based representation of snow dynamics contributed to the model's high‐resolution forcing data, and a sophisticated 3D geological model helped to define and parameterize its subsurface structure. In the first known attempt to calibrate a catchment‐scale integrated model of a mountainous region automatically, numerous uncertain model parameters were estimated. The salient features of the hydrological regime could ultimately be satisfactorily reproduced – over an 11‐month evaluation period, the Nash‐Sutcliffe efficiency of simulated streamflow at the main gauging station was 0.76. Spatio‐temporal visualization of the forcing data and simulated responses further confirmed the model's broad coherence. Presumably due to unresolved local subsurface heterogeneity, closely replicating the somewhat contrasting groundwater level signals observed near to one another proved more elusive. Finally, we assessed the impacts of various simplifications and assumptions that are commonly employed in physically‐based modeling – including the use of spatially uniform forcings, a vertically limited model domain, and global geological data products – on key simulated outputs, finding strongly affected model performance in many cases. Although certain outstanding challenges must be overcome if the uptake of integrated models in mountain regions around the world is to increase, our work demonstrates the feasibility and benefits of their application in such complex systems.
Plain Language Summary
Most popular hydrological models, which are tailored toward reproducing stream discharge measurements, neglect or strongly simplify spatial differences in environmental properties and/or physical processes, especially those related to the subsurface. This may limit their ability to provide reliable and useful future predictions, especially in regions with considerable climatic, topographic, geological, and hydrological complexity, such as the world's mountains. Here, we developed a more comprehensive and explicit representation of an Alpine hydrological system that is based on established physical principles and extensive data. We then applied the model to demonstrate that historical stream discharge and groundwater observations could be reproduced acceptably. We further generated several additional versions of the model by replicating current standard practices in physically‐based simulation approaches in order to test their impacts on model outputs. We report high sensitivity in certain instances. Overall, our approach offers the possibility to test alternative conceptual models or hypotheses of system behavior, better understand the data requirements and degree of model complexity necessary to robustly simulate the hydrology of relatively data poor mountain regions, and ultimately deliver more reliable and holistic hydrological climate change impact assessments to policy and decision makers.
Key Points
A structurally detailed integrated model of two adjacent steep, snow‐dominated, geologically complex Alpine headwaters was developed and calibrated automatically
Spatio‐temporal dynamics and interdependencies of snow, surface water, groundwater, and evapotranspiration processes were represented
Systematically substituting commonly used subsurface simplifications into the reference model strongly affected simulated dynamics
It is difficult to predict adverse patient outcomes associated with transvenous lead extraction (TLE) procedures.
The purpose of this study was to examine the safety and efficacy of chronic ...endovascular pacemaker and implantable cardioverter-defibrillator (ICD) lead extraction and risk factors associated with adverse patient outcomes.
Consecutive patients undergoing TLE at the Cleveland Clinic between August 1996 and August 2011 were included in the analysis. Univariate and multivariable logistic regression analyses were performed to evaluate for associations with outcomes. Continuous data are given as median (25th, 75th percentile). Categorical data are given as number (percentage).
In total, 5521 leads (4137 74.9% pacemaker, 1384 25.1% ICD) were extracted during 2999 TLE procedures (patient age 67.2 55.2, 76.2 years, 30.2% female). Lead implant duration was 4.7 (2.4, 8.3) years, and 2.0 (1.0, 2.0) leads were extracted per procedure. Powered sheaths were used in 74.9% of procedures. Overall, there was 95.1% complete procedural success, 98.9% clinical success, and 1.1% failure, with 3.6% minor complications and 1.8% major complications. All-cause mortality within 30 days of TLE was 2.2%. Multivariable predictors of major complications included cerebrovascular disease, ejection fraction ≤15%, lower platelet count, international normalized ratio ≥1.2, mechanical sheaths, and powered sheaths. Multivariable predictors of all-cause mortality within 30 days of TLE included body mass index <25 kg/m(2), end-stage renal disease, higher New York Heart Association functional class, lower hemoglobin, higher international normalized ratio, lead extraction for infection, and extraction of a dual-coil ICD lead.
TLE in this single-center experience was highly successful. Risk factors associated with adverse patient outcomes were identified.
Alluvial sand and gravel (ASG) aquifers are highly heterogeneous and exhibit strong, spatially variable anisotropy, often interspersed by buried paleo‐channels of increased hydraulic conductivity. ...Groundwater flow and solute transport is often characterized by preferential flow caused by anisotropic properties in ASG aquifers. Connected ASG subsurface structures such as buried paleo‐channels, however, are difficult to reproduce with commonly used techniques, and anisotropy is rarely considered in applied groundwater models. To ease the notoriously difficult problem of how to consider anisotropy, we propose a novel modeling framework based on calibration of an integrated surface‐subsurface hydrological model via spatially varying, preferred anisotropy pilot point inversion. The inversion leverages hydraulic and tracer‐based observations representing multiple spatial and temporal scales. We demonstrate the applicability of the framework on a real‐world ASG site used for drinking water production, and we quantify the information content of observations to identify connected paleo‐channels and provide guidance for optimal field‐data acquisition.
Plain Language Summary
Mountainous river corridors are used worldwide for drinking water production, as they represent a relatively safe and sustainable source of drinking water. The valley‐fill of mountainous river corridors is a result of millennia of fluvio‐glacial erosion and deposition via braided river systems and consists primarily of poorly sorted sand and gravel. Groundwater flow and solute transport through such alluvial sand and gravel (ASG) aquifers is characterized by preferential flow paths caused by formerly active, now buried meanders (i.e., paleo‐channels). The identification of paleo‐channels in ASG aquifers is crucial for safe drinking water production, but they are notoriously difficult to identify with the commonly used techniques. We propose a new modeling framework based on the calibration of an integrated surface‐subsurface hydrological model via spatially varying, preferred anisotropy pilot point inversion using both hydraulic and tracer observations. The new modeling framework is more efficient than other approaches to model flow through complex ASG aquifers and doesn't require precise prior knowledge of the location of paleo‐channels. The applicability and robustness of the framework is demonstrated on an ASG drinking water wellfield located in the Swiss Alps.
Key Points
Novel framework for identifying and quantifying groundwater flow through buried paleo‐channels
Heterogeneous hydraulic conductivity fields were identified based on spatially varying, preferred anisotropy‐constrained inversion
The fraction of infiltrating stream water in the aquifer and stream‐aquifer exchange fluxes best inform the paleo‐channel
The outcomes of patients requiring emergent surgical or endovascular intervention during transvenous lead extraction (TLE) have not been well characterized.
To evaluate the incidence of catastrophic ...complications requiring emergent surgical or endovascular intervention during TLE, to describe the injuries, and to review patient management and outcomes.
Consecutive patients undergoing TLE of pacemaker and implantable cardioverter-defibrillator (ICD) leads at the Cleveland Clinic between August 1996 and September 2012 were included in the analysis.
A total of 5973 (4436 74.3% pacemaker and 1537 25.7% ICD) leads were extracted during 3258 TLE procedures (median 25th, 75th percentile patient age 67.0 55.0, 76.1 years; 69.2% men). The median (25th, 75th percentile) lead implant duration was 4.9 (2.4, 8.4) years, and 2.0 (1.0, 2.0) leads were extracted per procedure. Powered sheaths were used in 2369 (72.7%) procedures. Twenty-five (0.8%) patients experienced catastrophic complications requiring emergent surgical or endovascular intervention. Twenty patients (0.6%) required either sternotomy (n = 18) or thoracotomy (n = 2) for superior vena cava laceration (n = 15) and right atrial (n = 2) or ventricular (n = 3) perforation. Two patients required vascular repair at the procedural access site for either subclavian vein or artery laceration. Three patients were managed with an endovascular approach for superior vena cava laceration, left axillary artery laceration, and brachiocephalic vein and artery fistula. In-hospital mortality was 36.0% (6 procedural/operative deaths and 3 deaths during the same hospitalization).
Major vascular injury or cardiac perforation requiring emergent surgical or endovascular intervention during TLE is uncommon but carries significant in-hospital mortality. Despite high mortality, nearly two-thirds of these patients were rescued with immediate response and surgical or endovascular intervention.
Snow depth mapping in Alpine forests is of high importance for hydrogeology, ecology, tourism, and natural hazards prevention. Different remote sensing approaches have been employed for the precise ...mapping of snow depth within forests. However, optical sensors cannot provide below-canopy information. While Airborne Laser Scanning (ALS) systems have been used successfully in this context and allow obtaining data below canopies, the costs of acquisitions are very high, not allowing frequent data acquisitions. UAV-based Lidar technology potentially can provide the critical below-canopy information at lower cost and allows for frequent acquisitions.First attempts to employ a UAV-based Lidar system in forests have proven promising, but they are limited to flat forests and to grid-level snow depth calculations. In this study, we present UAV-based Lidar data of both flat and steep forests. Different Lidar processing workflows are analyzed and compared, and snow depth algorithms are used both at the point and the grid level. Whereas the UAV-Lidar system proved capable of mapping snow in both environments, the steep forests' data processing comes with greater challenges, especially for the 3D registration, ground classification, and point-to-point snow depth calculations.
Climate change affects both water resources and agricultural production. With rising temperatures and decreasing summer precipitation, it is expected that agricultural production will be increasingly ...limited by drought. Where surface- or groundwater resources are available for irrigation, an increase in water withdrawals for irrigation is to be expected. Therefore, quantitative approaches are required to anticipate and manage the expected conflicts related to increased water abstraction for irrigation. This project aims to investigate how agricultural production, water demand for irrigation, runoff and groundwater dynamics are affected by future climate change and how climate change impacts combined with changes in agricultural water use affect groundwater dynamics. To answer these research questions, a comprehensive, loosely coupled model approach was developed, combining models from three disciplines: an agricultural plant growth model, a hydrological model and a hydrogeological model. The model coupling was implemented and tested for an agricultural area located in Switzerland in which groundwater plays a significant role in providing irrigation water. Our suggested modelling approach can be easily adapted to other areas.
The model results show that yield changes are driven by drought limitations and rising temperatures. However, an increase in yield may be realized with an increase in irrigation. Simulation results show that the water requirement for irrigation without climate protection (RCP8.5) could increase by 40% by the end of the century with an unchanged growing season and by up to 80% with varietal adaptations. With climate change mitigation (RCP2.6) the increase in water demand for irrigation would be limited to 7%. The increase in irrigation (+12 mm) and the summer decrease in recharge rates (~20 mm/month) with decreasing summer precipitation causes a lowering of groundwater levels (40 mm) in the area in the late summer and autumn. This impact may be accentuated by an intensification of irrigation and reduced by extensification.
Display omitted
•Climate change affects both water resources and agricultural production. Decision making has to balance resources and food production.•An agricultural crop growth model, a hydrological model and a hydrogeological model were loosely coupled.•The model indicates to what extent the climate change induced decreasing yield can be balanced by irrigation.•The irrigation water requirement could increase by 7% (RCP2.6) and by 40% (RCP8.5) by the end of the century.•Increasing irrigation water abstractions would amplify seasonal groundwater fluctuations.
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