Media 1: Plasmonic particles set into fast orbital motion by an optical vortex beam

Originally published in Optics Express on 24 February 2014 (oe-22-4-4349

A Minimal Skeletal Mechanism for Combustion of CH₄/O₂/CO₂ Mixtures

In this paper, a minimal skeletal mechanism involving 20 species and 56 reactions was generated for CH₄/O₂/CO₂ mixtures from the GRI Mech 3.0 mechanism. The directed relation graph-aided sensitivity analysis (DRGASA) method was applied for mechanism reduction at the first step. Then, principle component analysis (PCA) was used for further reduction. The chemical reality of the generated skeletal mechanism was checked by the reaction pathways analysis of CH₄/O₂/CO₂ mixtures in a constant-pressure ignition process. Finally, the generated skeletal mechanism was validated by the ignition delay times, laminar flame speeds, important species concentrations, and extinction turning points in the conditions of various pressures, temperatures, O₂/CO₂ ratios, and equivalence ratios. Results showed that the developed skeletal mechanism could reproduce the results from the detailed mechanism

Evaluation of limited irrigation strategies to improve water use efficiency and wheat yield in the North China Plain

<div><p>The North China Plain is one of the most important grain production regions in China, but is facing serious water shortages. To achieve a balance between water use and the need for food self-sufficiency, new water efficient irrigation strategies need to be developed that balance water use with farmer net return. The Crop Environment Resource Synthesis Wheat (CERES-Wheat model) was calibrated and evaluated with two years of data which consisted of 3–4 irrigation treatments, and the model was used to investigate long-term winter wheat productivity and water use from irrigation management in the North China Plain. The calibrated model simulated accurately above-ground biomass, grain yield and evapotranspiration of winter wheat in response to irrigation management. The calibrated model was then run using weather data from 1994–2016 in order to evaluate different irrigation strategies. The simulated results using historical weather data showed that grain yield and water use was sensitive to different irrigation strategies including amounts and dates of irrigation applications. The model simulated the highest yield when irrigation was applied at jointing (T9) in normal and dry rainfall years, and gave the highest simulated yields for irrigation at double ridge (T8) in wet years. A single simulated irrigation at jointing (T9) produced yields that were 88% compared to using a double irrigation treatment at T1 and T9 in wet years, 86% of that in normal years, and 91% of that in dry years. A single irrigation at jointing or double ridge produced higher water use efficiency because it obtained higher evapotranspiration. The simulated farmer irrigation practices produced the highest yield and net income. When the cost of water was taken into account, limited irrigation was found to be more profitable based on assumptions about future water costs. In order to increase farmer income, a subsidy will likely be needed to compensate farmers for yield reductions due to water savings. These results showed that there is a cost to the farmer for water conservation, but limiting irrigation to a single irrigation at jointing would minimize impact on farmer net return in North China Plain.</p></div

Irrigation schedules simulated with the CERES-Wheat model.

<p>Irrigation schedules simulated with the CERES-Wheat model.</p

Distribution of precipitation, maximum (Tmax) and minimum temperature (Tmin) at Gaocheng, over 22 growth season.

<p>Distribution of precipitation, maximum (Tmax) and minimum temperature (Tmin) at Gaocheng, over 22 growth season.</p

Modeling Time-Varying Effects With Large-Scale Survival Data: An Efficient Quasi-Newton Approach

<p>Nonproportional hazards models often arise in biomedical studies, as evidenced by a recent national kidney transplant study. During the follow-up, the effects of baseline risk factors, such as patients’ comorbidity conditions collected at transplantation, may vary over time. To model such dynamic changes of covariate effects, time-varying survival models have emerged as powerful tools. However, traditional methods of fitting time-varying effects survival model rely on an expansion of the original dataset in a repeated measurement format, which, even with a moderate sample size, leads to an extremely large working dataset. Consequently, the computational burden increases quickly as the sample size grows, and analyses of a large dataset such as our motivating example defy any existing statistical methods and software. We propose a novel application of quasi-Newton iteration method to model time-varying effects in survival analysis. We show that the algorithm converges superlinearly and is computationally efficient for large-scale datasets. We apply the proposed methods, via a stratified procedure, to analyze the national kidney transplant data and study the impact of potential risk factors on post-transplant survival. Supplementary materials for this article are available online.</p

Simulated marginal net return (MNR), relative marginal net return (RMNR) and net water use (NWU) for different irrigation over 22 year seasons.

<p>Simulated marginal net return (MNR), relative marginal net return (RMNR) and net water use (NWU) for different irrigation over 22 year seasons.</p

Simulated grain and biomass yield for different irrigation treatments.

<p>The triangle indicates the median. The circle indicates the 75 and 25 percent. The middle line indicates 50 percent.</p

Water and nitrogen treatments in the experiments conducted at Gaocheng, China (2013–2015).

<p>Water and nitrogen treatments in the experiments conducted at Gaocheng, China (2013–2015).</p

Comparisons of measured and observed above-ground biomass (a for 2013–2014 and b for 2014–2015) and LAI (c for 2013–2014 and d for 2014–2015).

<p>a and c were used to calibrate the model, b and d were used to validate the model.</p