Exploring Agricultural Production Systems and Their Fundamental Components with System Dynamics Modelling

Agricultural production in the United States is undergoing marked changes due to rapid shifts in consumer demands, input costs, and concerns for food safety and environmental impact. Agricultural production systems are comprised of multidimensional components and drivers that interact in complex ways to influence production sustainability. In a mixed-methods approach, we combine qualitative and quantitative data to develop and simulate a system dynamics model that explores the systemic interaction of these drivers on the economic, environmental and social sustainability of agricultural production. We then use this model to evaluate the role of each driver in determining the differences in sustainability between three distinct production systems: crops only, livestock only, and an integrated crops and livestock system. The result from these modelling efforts found that the greatest potential for sustainability existed with the crops only production system. While this study presents a stand-alone contribution to sector knowledge and practice, it encourages future research in this sector that employs similar systems-based methods to enable more sustainable practices and policies within agricultural production

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

The global retinoblastoma outcome study : a prospective, cluster-based analysis of 4064 patients from 149 countries

DATA SHARING : The study data will become available online once all analyses are complete.BACKGROUND : Retinoblastoma is the most common intraocular cancer worldwide. There is some evidence to suggest that major differences exist in treatment outcomes for children with retinoblastoma from different regions, but these differences have not been assessed on a global scale. We aimed to report 3-year outcomes for children with retinoblastoma globally and to investigate factors associated with survival. METHODS : We did a prospective cluster-based analysis of treatment-naive patients with retinoblastoma who were diagnosed between Jan 1, 2017, and Dec 31, 2017, then treated and followed up for 3 years. Patients were recruited from 260 specialised treatment centres worldwide. Data were obtained from participating centres on primary and additional treatments, duration of follow-up, metastasis, eye globe salvage, and survival outcome. We analysed time to death and time to enucleation with Cox regression models. FINDINGS : The cohort included 4064 children from 149 countries. The median age at diagnosis was 23·2 months (IQR 11·0–36·5). Extraocular tumour spread (cT4 of the cTNMH classification) at diagnosis was reported in five (0·8%) of 636 children from high-income countries, 55 (5·4%) of 1027 children from upper-middle-income countries, 342 (19·7%) of 1738 children from lower-middle-income countries, and 196 (42·9%) of 457 children from low-income countries. Enucleation surgery was available for all children and intravenous chemotherapy was available for 4014 (98·8%) of 4064 children. The 3-year survival rate was 99·5% (95% CI 98·8–100·0) for children from high-income countries, 91·2% (89·5–93·0) for children from upper-middle-income countries, 80·3% (78·3–82·3) for children from lower-middle-income countries, and 57·3% (52·1-63·0) for children from low-income countries. On analysis, independent factors for worse survival were residence in low-income countries compared to high-income countries (hazard ratio 16·67; 95% CI 4·76–50·00), cT4 advanced tumour compared to cT1 (8·98; 4·44–18·18), and older age at diagnosis in children up to 3 years (1·38 per year; 1·23–1·56). For children aged 3–7 years, the mortality risk decreased slightly (p=0·0104 for the change in slope). INTERPRETATION : This study, estimated to include approximately half of all new retinoblastoma cases worldwide in 2017, shows profound inequity in survival of children depending on the national income level of their country of residence. In high-income countries, death from retinoblastoma is rare, whereas in low-income countries estimated 3-year survival is just over 50%. Although essential treatments are available in nearly all countries, early diagnosis and treatment in low-income countries are key to improving survival outcomes.The Queen Elizabeth Diamond Jubilee Trust and the Wellcome Trust.https://www.thelancet.com/journals/langlo/homeam2023Paediatrics and Child Healt

Computational experiments on three-dimensional molecular diffusion in porous media

ABSTRACT Estimations of apparent diffusion coefficients usually consist of curve-fitting the output of 1-D models to experimental laboratory-measured data from porous aggregates shaped in different forms. In this research, a computational exploration is presented on the alternative use of three-dimensional models for the same purpose. The outputs of the 3-D models were compared to results generated by one-dimensional formulations. The comparison showed that there are significant discrepancies in the concentration values output by the models. Percent differences ranging from 30 to 90% were calculated. Those different estimations suggest that different values of the apparent diffusion coefficient may be obtained if the threedimensional solution of the diffusion equation would be used to match experimental results

Advanced Techniques for Watershed Visualization

Analytical shaded relief is commonly used for visualization of Digital Elevation Models (DEMs). Sometimes, the quality of unaltered analytical shaded relief can be lacking for identification of streams and water divides. Hydroshading [1] is a technique that provides enhanced capabilities of visualization of hydrologically-meaningful topographical features. In this research, hydroshading algorithms are applied to NASA’s Shuttle Radar Topography Mission (SRTM) DEM datasets. The visualization technique is applied to coastal and inland watersheds in Mississippi (Saint Louis Bay and Luxapallila, respectively). The testing of hydroshading in these two areas shows that the technique is more effective in areas with moderate topographical relief than in low relief terrain. Combining hydroshading with standard threedimensional visualization of DEMs enhances identification of water divides and streams. Hydroshaded DEMs were used to manually delineate Luxapallila and Saint Louis Bay’s Wolf River catchments. Delineation results are comparable to output of standard automated delineation produced by GIS software (BASINS). 1

A Web-based Simulation System for Transport and Retention of Dissolved Contaminants in Soil

The movement of contaminants through the soil matrix is primarily a liquid phase process in which the chemical partitions between sorbed and dissolved phases. These phenomena have been modeled extensively and several computer models were developed. The use of those computer programs requires installation of the software in the users machine. Usually, post-processing of the numerical output provided by the software is required. In this paper, a web-based simulation environment for retention and transport of dissolved organic and inorganic compounds in soils is presented. The system was developed using Java and is based on the Multi-reaction Transport Model of heavy metals in soil. The mathematical and numerical formulation of the model is briefly sketched. The core computing components of the simulation environment were written in C or fortran for their computational efficiency. The emerging Java Native Interface (JNI) technique and the Swing interface were used to design a user-friendly simulator. Java security problems (due to the use of applets calling native libraries) are discussed and a solution to avoid security restrictions is provided. The simulation system provides interactive user control and real time visualization through standard web browsers. The Java-based simulation code was used to analyze a hypothetical soil contamination problem. The almost instantaneous visualization of results provided by the Java-based interface resulted in efficient and easy analyses. Although a performance comparison was not in mind, the evaluation of the same scenario using the original fortran code took three times as much total time (program run, evaluation of results and post-processing) as that using the Java simulation syste