Mathematical models of plant–soil interaction

2008 ◽  
Vol 366 (1885) ◽  
pp. 4597-4611 ◽  
Author(s):  
Tiina Roose ◽  
Andrea Schnepf
Keyword(s):  
Mathematical Models ◽  
Single Root ◽  
Advantages And Disadvantages ◽  
Plant Soil ◽  
Whole Plant ◽  
Scale Models ◽  
Food Shortages ◽  
Mathematical Techniques ◽  
Homogenization Methods

In this paper, we set out to illustrate and discuss how mathematical modelling could and should be applied to aid our understanding of plants and, in particular, plant–soil interactions. Our aim is to persuade members of both the biological and mathematical communities of the need to collaborate in developing quantitative mechanistic models. We believe that such models will lead to a more profound understanding of the fundamental science of plants and may help us with managing real-world problems such as food shortages and global warming. We start the paper by reviewing mathematical models that have been developed to describe nutrient and water uptake by a single root. We discuss briefly the mathematical techniques involved in analysing these models and present some of the analytical results of these models. Then, we describe how the information gained from the single-root scale models can be translated to root system and field scales. We discuss the advantages and disadvantages of different mathematical approaches and make a case that mechanistic rather than phenomenological models will in the end be more trustworthy. We also discuss the need for a considerable amount of effort on the fundamental mathematics of upscaling and homogenization methods specialized for branched networks such as roots. Finally, we discuss different future avenues of research and how we believe these should be approached so that in the long term it will be possible to develop a valid, quantitative whole-plant model.

Problems of Distance Education

2018 ◽  
Vol 7 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Rostislav Fojtík
Keyword(s):  
Distance Education ◽  
Distance Learning ◽  
Computer Science ◽  
Full Time ◽  
Advantages And Disadvantages ◽  
E Learning ◽  
Educational Requirements

Abstract Distance learning and e-learning have significantly developed in recent years. It is also due to changing educational requirements, especially for adults. The article aims to show the advantages and disadvantages of distance learning. Examples of the 20-year use of the distance learning form of computer science describe the difficulties associated with the implementation and implementation of this form of teaching. The results of students in the full-time and distance form of teaching in the bachelor’s study of computer science are compared. Long-term findings show that distant students have significantly lower scores in the first years of study than full-time bachelor students. In the following years of study, the differences diminish, and students’ results are comparable. The article describes the possibilities of improving the quality of distance learning.

Review of classification studies for machine learning in the development of intelligent management decision support systems

2020 ◽  
Vol 89 ◽  
pp. 20-29
Author(s):  
Sh. K. Kadiev ◽  
◽  
R. Sh. Khabibulin ◽  
P. P. Godlevskiy ◽  
V. L. Semikov ◽  
...  
Keyword(s):  
Machine Learning ◽  
Decision Support ◽  
Mathematical Models ◽  
Decision Support Systems ◽  
Support Systems ◽  
Management Decision ◽  
Classification Methods ◽  
Advantages And Disadvantages ◽  
Intelligent Management ◽  
Management Decision Support

Introduction. An overview of research in the field of classification as a method of machine learning is given. Articles containing mathematical models and algorithms for classification were selected. The use of classification in intelligent management decision support systems in various subject areas is also relevant. Goal and objectives. The purpose of the study is to analyze papers on the classification as a machine learning method. To achieve the objective, it is necessary to solve the following tasks: 1) to identify the most used classification methods in machine learning; 2) to highlight the advantages and disadvantages of each of the selected methods; 3) to analyze the possibility of using classification methods in intelligent systems to support management decisions to solve issues of forecasting, prevention and elimination of emergencies. Methods. To obtain the results, general scientific and special methods of scientific knowledge were used - analysis, synthesis, generalization, as well as the classification method. Results and discussion thereof. According to the results of the analysis, studies with a mathematical formulation and the availability of software developments were identified. The issues of classification in the implementation of machine learning in the development of intelligent decision support systems are considered. Conclusion. The analysis revealed that enough algorithms were used to perform the classification while sorting the acquired knowledge within the subject area. The implementation of an accurate classification is one of the fundamental problems in the development of management decision support systems, including for fire and emergency prevention and response. Timely and effective decision by officials of operational shifts for the disaster management is also relevant. Key words: decision support, analysis, classification, machine learning, algorithm, mathematical models.

scholarly journals Shaping Microstructure and Mechanical Properties of High-Carbon Bainitic Steel in Hot-Rolling and Long-Term Low-Temperature Annealing

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 384
Author(s):  
Tomasz Dembiczak ◽  
Marcin Knapiński
Keyword(s):  
Mathematical Models ◽  
Hot Rolling ◽  
Constitutive Equations ◽  
Rolling Process ◽  
Bainitic Steel ◽  
Compression Tests ◽  
High Carbon ◽  
Bainite Steel ◽  
Dilatometric Studies

Based on the research results, coefficients in constitutive equations, describing the kinetics of dynamic, meta-dynamic, and static recrystallization in high-carbon bainitic steel during hot deformation were determined. The developed mathematical model takes into account the dependence of the changing kinetics in the structural size of the preliminary austenite grains, the value of strain, strain rate, temperature, and time. Physical simulations were carried out on rectangular specimens. Compression tests with a flat state of deformation were carried out using a Gleeble 3800. Based on dilatometric studies, coefficients were determined in constitutive equations, describing the grain growth of the austenite of high-carbon bainite steel under isothermal annealing conditions. The aim of the research was to verify the developed mathematical models in semi-industrial conditions during the hot-rolling process of high-carbon bainite steel. Analysis of the semi-industrial studies of the hot-rolling and long-term annealing process confirmed the correctness of the predicted mathematical models describing the microstructure evolution.

scholarly journals Circular Agreements—Exploring the Role of Agreements and Deals as a Political Tool for a Circular Economy

2021 ◽  
Author(s):  
Nils Johansson
Keyword(s):  
Value Chain ◽  
Circular Economy ◽  
Policy Instruments ◽  
Alternative Form ◽  
Advantages And Disadvantages ◽  
Free Rider Problem ◽  
Political Governance ◽  
The Eu

AbstractA problem for a circular economy, embedded in its policies, tools, technologies and models, is that it is driven by the interests and needs of producers, rather than customers and users. This opinion paper focuses on an alternative form of governance—agreements, which thanks to their bargaining approach brings actors from across the value chain into the policy process. The purpose of this opinion paper is to uncover and analyse the potential of such agreements for a circular economy. Circular agreements aim at increasing the circulation of materials and are an emerging form of political governance within the EU. These agreements have different names, involve different actors and govern in different ways. However, circular agreements seem to work when other types of regulations fail to establish circulation. These agreements bring actors together and offer a platform for negotiating how advantages and disadvantages can be redistributed between actors in a way that is more suitable for a circular economy. However, circular agreements are dependent on other policy instruments to work and can generate a free-rider problem with uninvolved actors. The agreements may also become too detailed and long term, which leads to problem shifting and lock-ins, respectively.

scholarly journals COVID-19 Shutdown: A Qualitative Study on Pearls and Pitfalls

Proceedings ◽  
2021 ◽  
Vol 74 (1) ◽  
pp. 4
Author(s):  
Naciye Güliz Uğur
Keyword(s):  
Qualitative Study ◽  
Human Health ◽  
Social Distance ◽  
The Other ◽  
Adoption Of Technology ◽  
Family Ties ◽  
Advantages And Disadvantages ◽  
Modern Period ◽  
Long Term Impact

The extraordinary and tragic conditions that humanity has not experienced before in the modern period have become ordinary, namely, a “new normal” with the presence of the COVID-19 pandemic. COVID-19 has had frightening consequences for human health and has caused one million deaths as of September 2020. On the other hand, it has set a new standard of good habits, approaches, and benefits. Due to its global and long-term impact, this unique virus has laid the groundwork for unprecedented helping and sharing behaviors between people and countries. In this study, findings are compiled from the open-ended responses of 626 individuals, all of whom live in Turkey. Within the study’s scope, individuals were asked about the unique advantages and disadvantages of the restrictions imposed under COVID-19. While the categories of economy, social distance, and health came to the fore among the harms, the strengthening of family ties, adoption of technology, and the spread of solidarity culture were mentioned among the advantages.

Measuring complex for monitoring carbon dioxide in air

2021 ◽  
pp. 68-71
Author(s):  
Igor M. Ageev ◽  
Yuri M. Rybin
Keyword(s):  
Carbon Dioxide ◽  
High Selectivity ◽  
Distilled Water ◽  
Measuring Systems ◽  
Advantages And Disadvantages ◽  
Measuring Complex ◽  
Co2 Level ◽  
Carbon Dioxide Co2 ◽  
Term Monitoring

The advantages and disadvantages of infrared and electrochemical gas analyzers for carbon dioxide CO2 are described. The possibility of using conductometric sensors with distilled water for monitoring the CO2 content in the air has been investigated. Two identical measuring systems were manufactured, each containing two open-type conductometric cells, a matching device and a personal computer. With the help of these complexes, experiments were carried out on the simultaneous measurement of the CO2 content in the air in two places (a laboratory room and a building in a forest, located at a distance of 15 km from each other) with deliberately different daily dynamics of the CO2 level change. A special experiment was carried out, which made it possible to obtain an estimate of the inertia of conductometric cells and a conversion factor for the values of CO2 content into standard units of measurement. It is shown that the daily dynamics of changes in the electrical conductivity of distilled water in open cells corresponds to the expected dynamics of changes in the CO2 content in the rooms where the measurements were carried out. The operability of the measuring complex and the possibility of creating on its basis a device for long-term monitoring of the CO2 content in the air mixture of gases has been confirmed. The principal high selectivity of the measuring complex to CO2 in relation to other gases of the atmosphere has been established.

The role of motivation in talent selection and ­development in competitive sport

2021 ◽  
Keyword(s):  
Measurement Instrument ◽  
Psychological Characteristics ◽  
Advantages And Disadvantages ◽  
Current State ◽  
Talent Selection ◽  
Comprehensive Picture ◽  
Performance Development ◽  
The Right

The early and long-term development of promising young athletes is a decisive factor in being internationally competitive in top-level sports. Among the multitude of talent criteria suggested in the literature, motivation plays a prominent role in the area of psychological characteristics. It is recognised in practice and research as a relevant criterion for performance development across all sports. This article provides an overview of the current state of talent research in the field of motivation. First, the most common theories of motivation in competitive sports are described, then different measurement methods and their advantages and disadvantages as well as the predictive value of motivation for athletic performance are discussed. Finally, implications for practice are suggested. It can be summarised that motivation in sport is conceptualised and operationalised in different ways and that the decision for the right measurement instrument depends on the goal of the assessment. To get a comprehensive picture of an athlete’s motivational status, it is useful to assess several aspects of motivation through different methods.

scholarly journals Effects of Food Deprivation Duration on the Behavior and Metabolism of Black Rockfish (Sebastes schlegelii)

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 58
Author(s):  
Fengyuan Shen ◽  
Zonghang Zhang ◽  
Yiqiu Fu ◽  
Zhen Zhang ◽  
Xin Sun ◽  
...  
Keyword(s):  
Food Deprivation ◽  
Personality Assessment ◽  
Behavioral Assessment ◽  
Standard Metabolic Rate ◽  
Control Group ◽  
Black Rockfish ◽  
Swimming Time ◽  
Sebastes Schlegelii ◽  
Food Shortages

Fish often undergo food shortages in nature, especially for juveniles that are relatively vulnerable in most aspects. Therefore, the effects of food deprivation on fish behavior and physiology are worth exploring. Here, we investigated the behavioral and metabolic adaptations of the juvenile black rockfish Sebastes schlegelii to different durations of food deprivation. In this study, three treatments were set: control group, short-term food deprivation (STFD) group, and long-term food deprivation (LTFD) group. The rearing lasted for six weeks. During this period, videos were recorded three times per week to assess the locomotor activity and aggression. After this, the fishes’ boldness, neophobia, and aggressiveness were assessed using different behavioral assessment devices, while the standard metabolic rate (SMR) was measured by flow-type respirometry. In general, the values of the four indicators (swimming time, the number of turns, movement number, and attack number) for the STFD group were significantly higher than those for the control and LTFD group during the same period of rearing. In a subsequent personality assessment, the STFD group was observed to be significantly bolder in an assessment measuring boldness than the control and LTFD group (indicated by time in the circle, swimming time, number of times through the circle, and frequency in the circle). The LTFD group was observed to be more exploratory in the assessment of neophobia (indicated by duration in the exploratory area, distance from novelty item, and frequency of stay in the exploratory area). Indeed, the LTFD group was observed to be significantly less aggressive in the assessment of aggressiveness than the control and STFD group (indicated by attack number, attack range frequency, first attack, and winner). SMR was noted to be significantly higher in the STFD group than in the control and LTFD group. In conclusion, this study firstly reported the effects of food deprivation duration on the personalities of black rockfish, as well as the behavioral and physiological mechanisms. Thus, we hope to provide insights into the work of stock enhancement.

scholarly journals World Experience in Creating Mathematical Models of Air Springs: Advantages and Disadvantages

2021 ◽  
pp. 25-42
Author(s):  
A. Y Kuzyshyn ◽  
S. A Kostritsia ◽  
Yu. H Sobolevska ◽  
А. V Batih
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Behavior ◽  
High Speed ◽  
Vertical Direction ◽  
Rolling Stock ◽  
Air Spring ◽  
Advantages And Disadvantages ◽  
Mechanical Models

Purpose. Taking into account the production and commissioning of modern high-speed rolling stock, the authors are aimed to analyze the currently created mathematical models describing the dynamic behavior of the air spring, systematize them and consider the advantages and disadvantages of each model type. Methodology. For the analysis, a comparative chronological method was used, which makes it possible to trace the development of several points of view, concepts, theories. In accordance with the adopted decision equations, the existing models of air springs were divided into three groups: mechanical, thermodynamic and finite-elements. When analyzing mathematical models, the influence of a number of parameters on the dynamic behavior of the air spring, such as disturbing force frequency, heat transfer, nonlinear characteristics of materials, the shape of the membrane, etc., was considered. Findings. A feature of mechanical models is the determination of input parameters based on the analysis of experimental results, requires access to complex measuring equipment and must be performed for each new model of an air spring separately. Unlike mechanical models, which allow taking into account the damping effect of an air spring in the horizontal and vertical direction, thermodynamic models are mainly focused on studying the dynamic behavior of an air spring in the vertical direction. The use of the finite element method makes it possible to most accurately reproduce the dynamic behavior of an air spring, however, it requires significant expenditures of time and effort to create a finite element model and perform calculations. Originality. Mathematical models of the dynamic behavior of an air spring are systematized, and the importance of their study in conjunction with a spatial mathematical model of high-speed rolling stock is emphasized. Practical value. The analysis of the mathematical models of the dynamic behavior of the air spring shows the ways of their further improvement, indicates the possibility of their use in the spatial mathematical model of the rolling stock in accordance with the tasks set. It will allow, even at the design stage of high-speed rolling stock, to evaluate its dynamic characteristic and traffic safety indicators when interacting with a railway track.

scholarly journals Closest and long-term prospects of 3D-printing for obstetrics and gynecology

2021 ◽  
Vol 20 (1) ◽  
pp. 76-81
Author(s):  
E. V. Kudryavtseva ◽  
V. V. Kovalev ◽  
E. S. Zakurinova ◽  
G. Muller-Kamskii ◽  
V. V. Popov
Keyword(s):  
3D Printing ◽  
Scientific Literature ◽  
Simulation Models ◽  
Surgical Instruments ◽  
Obstetrics And Gynecology ◽  
Scientific Review ◽  
Advantages And Disadvantages ◽  
The Creation ◽  
Dimensional Printing

Introduction. Despite the notable and rapid progress in the development of medical 3D printing in recent years, not much is known about the use of this technology in obstetrics and gynecology.The purpose of our review of scientific literature was to determine the current level of 3D printing development, discuss the closest and long term prospects for using this technology in obstetrics and gynecology, and analyze its potential advantages and disadvantages.Materials and methods. We searched for scientific literature. 378 papers passed a three-step screening, as a result of which 42 sources were selected for the final scientific review.Results and discussion. The main areas in which dimensional printing can be used in this area of medicine is the creation of simulation models and training for students, the creation of anatomical models for preoperative preparation, the surgical instruments, the creation of new dosage drug forms (including transvaginal ones), and bioprinting of organs and tissues.Conclusion. The presented literary review allows us to conclude that 3D printing the obstetrics and gynecology is a current rapidly developing direction. The organization of 3D modeling and printing laboratories can significantly increase the efficiency of teaching students and residents. In addition, obstetricians-gynecologists and surgeons should be informed about the possibility of 3D printing surgical instruments according to an individual design. It can inspire them to implement their own ideas and develop domestic innovative developments. Three-dimensional printing of dosage forms and bioprostheses requires more complex technological solutions, and is not yet used in clinical practice. However, given the enormous prospects for these areas, various grants should be envisaged for their development in Russia

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