Quantifying water-use efficiency in plant canopies with varying leaf angle and density distribution.

BACKGROUND AND AIMS: Variation in architectural traits related to the spatial and angular distribution of leaf area can have considerable impacts on canopy-scale fluxes contributing to water-use efficiency (WUE). These architectural traits are frequent targets for crop improvement and for improving the understanding and predictions of net ecosystem carbon and water fluxes. METHODS: A three-dimensional, leaf-resolving model along with a range of virtually generated hypothetical canopies were used to quantify interactions between canopy structure and WUE by examining its response to variation of leaf inclination independent of leaf azimuth, canopy heterogeneity, vegetation density and physiological parameters. KEY RESULTS: Overall, increasing leaf area index (LAI), increasing the daily-averaged fraction of leaf area projected in the sun direction (Gavg) via the leaf inclination or azimuth distribution and increasing homogeneity had a similar effect on canopy-scale daily fluxes contributing to WUE. Increasing any of these parameters tended to increase daily light interception, increase daily net photosynthesis at low LAI and decrease it at high LAI, increase daily transpiration and decrease WUE. Isolated spherical crowns could decrease photosynthesis by ~60 % but increase daily WUE ≤130 % relative to a homogeneous canopy with equivalent leaf area density. There was no observed optimum in daily canopy WUE as LAI, leaf angle distribution or heterogeneity was varied. However, when the canopy was dense, a more vertical leaf angle distribution could increase both photosynthesis and WUE simultaneously. CONCLUSIONS: Variation in leaf angle and density distributions can have a substantial impact on canopy-level carbon and water fluxes, with potential trade-offs between the two. These traits might therefore be viable target traits for increasing or maintaining crop productivity while using less water, and for improvement of simplified models. Increasing canopy density or decreasing canopy heterogeneity increases the impact of leaf angle on WUE and its dependent processes.

Kinetic factors of physiology and the dynamic light environment influence the economic landscape of short-term hydraulic risk.

Optimality-based models of stomatal conductance unify biophysical and evolutionary constraints and can improve predictions of land-atmosphere carbon and water exchange. Recent models incorporate hydraulic constraints by penalizing excessive stomatal opening in relation to hydraulic damage caused by low water potentials. We used simulation models to test whether penalties based solely on vulnerability curves adequately represent the optimality hypothesis, given that they exclude the effects of kinetic factors on stomatal behavior and integrated carbon balance. To quantify the effects of nonsteady-state phenomena on the landscape of short-term hydraulic risk, we simulated diurnal dynamics of leaf physiology for 10 000 patches of leaf in a canopy and used a ray-tracing model, Helios, to simulate realistic variation in sunfleck dynamics. Our simulations demonstrated that kinetic parameters of leaf physiology and sunfleck properties influence the economic landscape of short-term hydraulic risk, as characterized by the effect of stomatal strategy (gauged by the water potential causing a 50% hydraulic penalty) on both aggregated carbon gain and the aggregated carbon cost of short-term hydraulic risk. Hydraulic penalties in optimization models should be generalized to allow their parameters to account for kinetic factors, in addition to parameters of hydraulic vulnerability.

Catching Spores: Linking Epidemiology, Pathogen Biology, and Physics to Ground-Based Airborne Inoculum Monitoring.

Monitoring airborne inoculum is gaining interest as a potential means of giving growers an earlier warning of disease risk in a management unit or region. This information is sought by growers to aid in adapting to changes in the management tools at their disposal and the market-driven need to reduce the use of fungicides and cost of production. To effectively use inoculum monitoring as a decision aid, there is an increasing need to understand the physics of particle transport in managed and natural plant canopies to effectively deploy and use near-ground aerial inoculum data. This understanding, combined with the nuances of pathogen-specific biology and disease epidemiology, can serve as a guide to designing improved monitoring approaches. The complexity of any pathosystem and local environment are such that there is not a generalized approach to near-ground air sampler placement, but there is a conceptual framework to arrive at a "semi-optimal" solution based on available resources. This review is intended as a brief synopsis of the linkages among pathogen biology, disease epidemiology, and the physics of the aerial dispersion of pathogen inoculum and what to consider when deciding where to locate ground-based air samplers. We leverage prior work in developing airborne monitoring tools for hops, grapes, spinach, and turf, and research into the fluid mechanics governing particle transport in sparse canopies and urban and forest environments. We present simulation studies to demonstrate how particles move in the complex environments of agricultural fields and to illustrate the limited sampling area of common air samplers.

Single-Step Integration of Poly(3-Octylthiophene) and Single-Walled Carbon Nanotubes for Highly Reproducible Paper-Based Ion-Selective Electrodes.

Calibration of ion-selective electrodes (ISEs) is cumbersome, time-consuming, and constitutes a significant limitation for the development of single-use and wearable disposable sensors. To address this problem, we have studied the effect of ion-selective membrane solvent on ISE reproducibility by comparing tetrahydrofuran (THF) (a typical solvent for membrane preparation) and cyclohexanone. In addition, a single-step integration of semiconducting/transducer polymer poly(3-octylthiophene) (POT) with single-walled carbon nanotubes (SWCNTs) into the paper-based ISEs (PBISEs) substrate was introduced. PBISEs for potassium and sodium ions were developed, and these ISEs present outstanding sensor performance and high potential reproducibility, as low as ±1.0 mV (n = 3).

Radiation exposure during cardiac catheterisation is similar for both femoral and radial approaches.

OBJECTIVES: Radial approach invasive coronary angiography has been shown to be superior to the femoral approach in terms of reducing vascular access complications and improving patient comfort. However, one major limitation has been the perception of higher patient radiation exposure, with guidelines recommending 7mSv as an appropriate average effective dose (E) for routine coronary angiography. Therefore, we sought here to assess differences in radiation exposure between the femoral and radial access routes in patients undergoing diagnostic coronary angiography with or without angioplasty (CA +/- PCI), as performed by two operators, experienced in both techniques. METHODS: Consecutive patients (n=870) from July 2011-December 2012, undergoing routine CA +/- PCI at Royal Prince Alfred Hospital, Sydney by two experienced interventional cardiologists were identified. Radiation doses were automatically recorded as dose area products (DAPs) at procedure time and converted into E using a conversion factor of 0.18 mSv/(Gycm2), as validated by the National Radiological Protection Board (NRPB). RESULTS: Of the 870 patients, 598 underwent diagnostic CA (347 femoral, 251 radial); and 272 underwent CA+ PCI (179 femoral, 93 radial). The mean age of the patients was 65±12 years and the majority (n=617, 71%) were male. Both groups were well matched with respect to baseline demographics, clinical presentation and angiographic characteristics, though there was an excess of patients with a history of coronary grafts in the femoral group, due to operator preference. In the patients who underwent diagnostic CA, there was no significant difference in the average effective radiation dose for femoral versus radial arterial access (E=7.9±8.2 vs. 8.3±10.6mSv; p=0.66). Similarly, there was also no difference in average effective radiation dose for femoral versus radial arterial access in patients undergoing CA+PCI (E=13.2±8.1 vs E=14.4±8.3 mSv; p=0.26). CONCLUSION: In our high volume cardiac catheterisation laboratory, radiation doses for routine angiography were near UNSC targets. Patient radiation exposure was comparable between femoral and radial approaches, for both CA and CA +/- PCI. Thus, our results allay concerns that radial cardiac catheterisation might be associated with greater radiation exposure.

The accuracy of the compressible Reynolds equation for predicting the local pressure in gas-lubricated textured parallel slider bearings.

The validity of the compressible Reynolds equation to predict the local pressure in a gas-lubricated, textured parallel slider bearing is investigated. The local bearing pressure is numerically simulated using the Reynolds equation and the Navier-Stokes equations for different texture geometries and operating conditions. The respective results are compared and the simplifying assumptions inherent in the application of the Reynolds equation are quantitatively evaluated. The deviation between the local bearing pressure obtained with the Reynolds equation and the Navier-Stokes equations increases with increasing texture aspect ratio, because a significant cross-film pressure gradient and a large velocity gradient in the sliding direction develop in the lubricant film. Inertia is found to be negligible throughout this study.

Simulation of Automatically Annotated Visible and Multi-/Hyperspectral Images Using the Helios 3D Plant and Radiative Transfer Modeling Framework.

Deep learning and multimodal remote and proximal sensing are widely used for analyzing plant and crop traits, but many of these deep learning models are supervised and necessitate reference datasets with image annotations. Acquiring these datasets often demands experiments that are both labor-intensive and time-consuming. Furthermore, extracting traits from remote sensing data beyond simple geometric features remains a challenge. To address these challenges, we proposed a radiative transfer modeling framework based on the Helios 3-dimensional (3D) plant modeling software designed for plant remote and proximal sensing image simulation. The framework has the capability to simulate RGB, multi-/hyperspectral, thermal, and depth cameras, and produce associated plant images with fully resolved reference labels such as plant physical traits, leaf chemical concentrations, and leaf physiological traits. Helios offers a simulated environment that enables generation of 3D geometric models of plants and soil with random variation, and specification or simulation of their properties and function. This approach differs from traditional computer graphics rendering by explicitly modeling radiation transfer physics, which provides a critical link to underlying plant biophysical processes. Results indicate that the framework is capable of generating high-quality, labeled synthetic plant images under given lighting scenarios, which can lessen or remove the need for manually collected and annotated data. Two example applications are presented that demonstrate the feasibility of using the model to enable unsupervised learning by training deep learning models exclusively with simulated images and performing prediction tasks using real images.

Practical Considerations and Limitations of Using Leaf and Canopy Temperature Measurements as a Stomatal Conductance Proxy: Sensitivity across Environmental Conditions, Scale, and Sample Size.

Stomatal conductance (gs) is a crucial component of plant physiology, as it links plant productivity and water loss through transpiration. Estimating gs indirectly through leaf temperature (Tl) measurement is common for reducing the high labor cost associated with direct gs measurement. However, the relationship between observed Tl and gs can be notably affected by local environmental conditions, canopy structure, measurement scale, sample size, and gs itself. To better understand and quantify the variation in the relationship between Tl measurements to gs, this study analyzed the sensitivity of Tl to gs using a high-resolution three-dimensional model that resolves interactions between microclimate and canopy structure. The model was used to simulate the sensitivity of Tl to gs across different environmental conditions, aggregation scales (point measurement, infrared thermometer, and thermographic image), and sample sizes. Results showed that leaf-level sensitivity of Tl to gs was highest under conditions of high net radiation flux, high vapor pressure deficit, and low boundary layer conductance. The study findings also highlighted the trade-off between measurement scale and sample size to maximize sensitivity. Smaller scale measurements (e.g., thermocouple) provided maximal sensitivity because they allow for exclusion of shaded leaves and the ground, which have low sensitivity. However, large sample sizes (up to 50 to 75) may be needed to differentiate genotypes. Larger-scale measurements (e.g., thermal camera) reduced sample size requirements but include low-sensitivity elements in the measurement. This work provides a means of estimating leaf-level sensitivity and offers quantitative guidance for balancing scale and sample size issues.

Improving a patient appointment call center at Mayo Clinic.

PURPOSE: Contact centers for patient and referring physician are important to large medical-centers such as the Mayo Clinic's Central Appointment Office (CAO). The aim of this case study is to report the process and results of a major process improvement effort, designed to simultaneously improve service quality and efficiency. DESIGN/METHODOLOGY/APPROACH: Discrete-event simulation and optimization are used and linked to significant service improvements. FINDINGS: The process improvement efforts led to about a 70 percent improvement in patient service performance as measured by average answering-speed (ASA) and average abandonment rate (AAR). This was achieved without adding additional staff, despite call volume increasing by 12 percent. Evaluating process improvement projects is difficult owing to the "phased" implementation of changes. Thus, there is no true control against which to compare. Additionally, the results are based on a single case study. RESEARCH LIMITATIONS/IMPLICATIONS: Evaluation of process improvement projects is difficult due to the "phased" implementation of changes. Thus, there is no true control to compare against. PRACTICAL IMPLICATIONS: Contact center data and operations research methods, such as discrete-event simulation and optimization, can be integrated with change management, which results in significant process improvements in medical call-centers. ORIGINALITY/VALUE: Structured quantitative modeling of contact centers can be an important extension to traditional quality and process improvement techniques.

Appointment Pathways: Yield Management via Cause-and-Effect Modeling in the Outpatient Setting at Mayo Clinic.

Patients have multiple outpatient appointments for various reasons. Analyzing patients' related appointments provides insight into referral patterns, leading to recommendations for ideal care and more efficient planning. We model these appointments with causal graphs via Judea Pearl's causal graph approach. Once we define the causal relationships in the appointment data, we leverage a graph database and visualization software to investigate valuable patterns and relationships in patient care over time. The Pathways tool allows yield management at specialty, provider, or appointment levels. Leaders use this tool to anticipate a patient's downstream appointments; the tool provides insights into staffing and the impact of growing demand.

Platypnea-Orthodeoxia Syndrome in the Setting of Patent Foramen Ovale Without Pulmonary Hypertension or Major Lung Disease.

Background Patent foramen ovale (PFO)-associated platypnea-orthodeoxia syndrome is characterized by dyspnea and hypoxemia when upright. The pathogenesis is thought to involve an increase in right atrial pressure or change in degree of right to left shunting with upright posture. Methods and Results We sought to characterize patients with platypnea-orthodeoxia syndrome related to PFO without pulmonary hypertension. We retrospectively reviewed databases at 3 tertiary referral hospitals in New South Wales, Australia from 2000 to 2019. Fourteen patients with a mean age of 69±14 years had a PFO with wide tunnel separation. Mean New York Heart Association Classification was II (±0.9) and 7 inpatients had been confined to bed (from postural symptoms). Baseline oxygen saturations supine were 93%±5% and 84%±6% upright. Two patients had a minor congenital heart defect and 4 had mild parenchymal lung disease with preserved lung function. The mean aortic root diameter was 37±6 mm and distance between aortic root and posterior atrial wall was 16±2 mm. Platypnea-orthodeoxia syndrome was preceded by surgery in 5 patients and 1 patient had mild pneumonia. Successful closure of the PFO using an Amplatzer device was performed in 11 of 14 patients. Post-closure, all patients had New York Heart Association Classification I (improvement 1.6±0.9, P<0.003) and semi-recumbent oxygen saturations increased by 13%±8% (P<0.001, n=10). Conclusions Platypnea-orthodeoxia syndrome is a debilitating condition, curable by PFO closure. Anatomical distortion of the atrial septum related to a dilated aortic root or shortening of the distance between the aortic root and posterior atrial wall may contribute to the syndrome.

The relationship between pulmonary artery and pulmonary capillary wedge pressure for the diagnosis of pulmonary vascular disease.

BACKGROUND: Left heart disease and pulmonary vascular disease (PVD) both lead to raised pulmonary artery pressure (PAP) but differ in pathophysiology, prognosis and treatment. There are currently no criteria for diagnosing PVD in the presence of left heart disease. We therefore studied the relationship between PAP and pulmonary capillary wedge pressure (PCWP, a measure of left atrial pressure) to help define when PAP should be considered 'out-of-proportion' to PCWP, thus suggestive of PVD. METHODS: Retrospective analysis of 898 consecutive simultaneous left and right heart catheterisations. Of these, 684 patients (age 63+/-14 years) were classified according to presence of absence of left heart disease. Multilinear regression explored the relationship between mean PAP and PCWP, age, gender, systemic haemodynamics and left heart disease diagnosis. RESULTS: Increasing PCWP, age and heart rate and female gender were associated with higher PAP (p<0.0001, p=0.049, p<0.0001 and p=0.0015, respectively). Thus, in males: (mean PAP)=0.94+[1.15 x (mean PCWP)]+[0.03 x (age)]+[0.07 x (heart rate)] (for females add 1.38 mm Hg). This model accounted for 75% of variability in PAP, with PCWP alone accounting for 74%. CONCLUSIONS: A strong linear relationship exists between PAP and PCWP, which may help identify PAP 'out-of-proportion' to PCWP, facilitating the diagnosis of PVD in patients with pulmonary hypertension and left heart disease.

Thoracic cancer surgeries.

In 2005, Cancer Care Ontario (CCO) released Thoracic Surgical Oncology Standards. These standards were aimed at providing the best level of care for those undergoing thoracic surgery and encompass surgeon training, hospital ancillary services and minimum volume thresholds for surgeries of the lung and esophagus. The objective of the current study was to explore variations in thoracic cancer surgical volumes at the hospital level across Canada. Using data from the Discharge Abstract Database for 2007-2008, the cohort included patients admitted to hospital with a most responsible diagnosis of cancer and who had a lung or esophageal surgery. To determine the volume of surgeries performed per facility, we grouped patients according to the hospital facility performing the surgery. In Canada (excluding Quebec and Prince Edward Island), there were a total 4,509 lung and 587 esophageal cancer procedures performed in 94 hospitals in 2007-2008. For both types of surgeries, Ontario hospitals performed approximately half of the procedures. Overall, 12 hospitals performed at or over the volume of surgeries for lung cancer as indentified by the CCO standards, while 10 did so for esophageal cancer. Nine hospitals performed both lung and esophageal cancer surgeries at or over the suggested volumes. Higher volumes of lung and esophageal cancer-related surgeries have been associated with improved patient outcomes. Here we present a snapshot of the distribution of cancer-related lung and esophageal surgeries across Canada (excluding Quebec and Prince Edward Island).

Helios: A Scalable 3D Plant and Environmental Biophysical Modeling Framework.

This article presents an overview of Helios, a new three-dimensional (3D) plant and environmental modeling framework. Helios is a model coupling framework designed to provide maximum flexibility in integrating and running arbitrary 3D environmental system models. Users interact with Helios through a well-documented open-source C++ API. Version 1.0 comes with model plug-ins for radiation transport, the surface energy balance, stomatal conductance, photosynthesis, solar position, and procedural tree generation. Additional plug-ins are also available for visualizing model geometry and data and for processing and integrating LiDAR scanning data. Many of the plug-ins perform calculations on the graphics processing unit, which allows for efficient simulation of very large domains with high detail. An example modeling study is presented in which leaf-level heterogeneity in water usage and photosynthesis of an orchard is examined to understand how this leaf-scale variability contributes to whole-tree and -canopy fluxes.

Determinants of coronary arterial flow-mediated dilatation following percutaneous coronary intervention.

OBJECTIVE: It has previously been observed that coronary diameter may increase following relief of flow-limiting obstruction. Flow mediated dilatation (FMD) is a fundamental adaptive mechanism for arteries, which is dependent on intact endothelial function. We thus aimed to characterize whether the degree of this flow-mediated dilatation was related to risk factors, which may impair endothelial function. DESIGN: We measured coronary diameter with quantitative angiography before and after relief of chronic total or subtotal (>or=99%) occlusion in 171 patients, in which TIMI-0 or TIMI-1 flow was rapidly restored to TIMI-3 (with attendant increase in flow hypothesized to result in FMD). PATIENTS: Of the 171 patients, 73% were male, 62% were current or ex-smokers, 47% were diabetic, 53% had hypertension, 64% had dyslipidemia (documented hypercholesterolemia or total cholesterol >5.0 mg/dL) and 65% were taking statin therapy. RESULTS: Mean vessel diameter was 2.8 +/- 0.7 mm and flow-mediated dilatation measured 15.1% +/- 20.1% in target vessel, compared with 1.6 +/- 3.1 in control vessels (P < 0.05). FMD was strongly and inversely related to baseline vessel diameter (r = -0.48, P < 0.001). The degree of vessel dilation correlated negatively with the presence of diabetes (r = -0.33, P < 0.001), smoking (r = -0.30, P < 0.001) and extent of coronary artery disease (CAD, r = -0.17, P = 0.01) and positively with the use of statins (r = 0.27, P = 0.001). These factors, apart from extent of CAD, remained significant predictors of FMD on multivariate analysis. CONCLUSIONS: FMD occurs in human coronary arteries following restoration of flow. The magnitude of FMD appears related to vascular risk factors and their treatment.

The monocytic lineage specific soluble CD163 is a plasma marker of coronary atherosclerosis.

BACKGROUND: CD163 is a monocyte-macrophage lineage specific scavenger receptor that mediates the uptake and clearance of haptoglobin-haemoglobin complexes, and soluble CD163 (sCD163) is also present in plasma. As atherosclerosis involves infiltration by monocyte-derived macrophages, we investigated whether sCD163 may act as a marker of coronary atherosclerosis (CAD). METHODS AND RESULTS: Clinical features were identified and plasma was collected from 147 consecutive patients presenting for coronary angiography. Patients were classified as having CAD+, or being free of CAD- haemodynamically significant (>50% luminal diameter) coronary stenoses in one or more major coronary arteries (1, 2 or 3 vessel disease), and sCD163 concentration was measured by ELISA. Plasma sCD163 was non-parametrically distributed, being significantly higher in CAD+ patients (median 2.47 mg/L, 25th-75th percentile, 1.79-3.5mg/L) than in CAD- patients (2.09, 1.31-2.72 mg/L) (p=0.021, Mann-Whitney U-test). LogsCD163 increased significantly with increasing CAD extent (p=0.0036) and was significantly greater in patients with 3 vessel disease than in CAD- patients (p<0.001). Whereas logsCD163 correlated with CAD extent (Spearman r=0.22, p=0.008), logCRP did not, and sCD163 was only weakly correlated with CRP (r=0.19, p=0.039). Importantly, multivariate linear regression identified that sCD163 (p=0.0021) was a significant predictor of CAD extent and was independent of conventional risk factors age (p<0.0001), hypercholesterolemia (p=0.0023), hypertension (p=0.068), and current smoking (p=0.066). CONCLUSIONS: The monocyte-specific marker sCD163 is a novel potential plasma marker of coronary atherosclerotic burden.

Validation and clinical utility of a simple in-home testing tool for sleep-disordered breathing and arrhythmias in heart failure: results of the Sleep Events, Arrhythmias, and Respiratory Analysis in Congestive Heart Failure (SEARCH) study.

Fifty patients with New York Heart Association class III systolic heart failure were enrolled in this prospective multicenter study that compared the diagnostic accuracy of a home-based cardiorespiratory testing system with standard attended polysomnography. Patients underwent at least 2 nights of evaluation and were scored by blinded observers. At diagnostic cutoff points of > or =5, > or =10, and > or =15 events per hour for respiratory disturbance severity, polysomnography demonstrated a sleep-disordered breathing prevalence of 69%, 59%, and 49%, respectively. Compared with polysomnography, the cardiorespiratory testing system demonstrated predictive accuracies of 73%, 73%, and 75%, which improved to 87%, 87%, and 83%, respectively, when analysis of covariance suggested reanalysis omitting one site's data. The system accurately identified both suspected and unsuspected arrhythmias. The device was judged by 80% of patients to be easy or very easy to use, and 74% of patients expressed a preference for the in-home system. Therefore, this system represents a reasonable home testing device in these patients.

The effectiveness of a specialized trauma course in the knowledge base and level of job satisfaction in emergency nurses.

The purpose of this study is to evaluate the level of job satisfaction of the emergency department nurses that care for trauma patients. The hospital is a Level I trauma center and tertiary care center that provides multiple services to more than 1.2 million people in 29 counties. The Trauma Service and the Emergency Department (ED) must define and maintain the same expectations. The level of job satisfaction of the emergency department nurses will define the success of safe and effective patient care in a Level I Trauma Center.