scholarly journals A theoretical model for optimal control of banana Moko (Musa AAB Simmonds)

F1000Research ◽  
2021 ◽  
Vol 9 ◽  
pp. 1443
Author(s):  
Marly Grajales Amorocho ◽  
Anibal Muñoz Loaiza
Keyword(s):  
Threshold Value ◽  
Production Costs ◽  
Logistic Growth ◽  
Optimal Conditions ◽  
Prevention Strategies ◽  
Maximum Capacity ◽  
Linear Ordinary Differential Equations ◽  
Variable Population ◽  
Population Simulation ◽  
Over Time

A population simulation model with non-linear ordinary differential equations is presented, which interprets the dynamics of the banana Moko, with prevention of the disease and population of susceptible and infected plants over time. A crop with a variable population of plants and a logistic growth of replanting is assumed, taking into account the maximum capacity of plants in the delimited study area. Also, with the help of farmers, the costs of implementing prevention strategies and elimination of infected plants were calculated per week in order to determine the optimal conditions that control the disease and reduce production costs. We found that the implementation of prevention strategies (f) plays an important role, but the parameter that most influences the threshold value is the elimination of infected plants g.  However, to reduce production costs due to the high implementation of prevention strategies and to maintain the disease in a controlled state, both controls u1 and u2 should be implemented between 40% and 60%, obtaining with this percentage an approximate reduction of 51.37% in production costs per week, where in 23 weeks following the same conditions it is expected to have a healthy plantation without infected plants.

scholarly journals A theoretical model for the prevention of Banana Moko (Musa AAB Simmonds)

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1443
Author(s):  
Marly Grajales Amorocho ◽  
Anibal Muñoz Loaiza
Keyword(s):  
Theoretical Model ◽  
Differential Equations ◽  
Simulation Model ◽  
Ordinary Differential Equations ◽  
Logistic Growth ◽  
Maximum Capacity ◽  
Linear Ordinary Differential Equations ◽  
Variable Population ◽  
Population Simulation ◽  
Over Time

A population simulation model with non-linear ordinary differential equations is presented, which interprets the dynamics of the banana Moko, with prevention of the disease and population of susceptible and infected plants over time. A crop with a variable population of plants and a logistic growth of replanting is assumed, taking into account the maximum capacity of plants in the delimited study area.

scholarly journals Stability and Hopf Bifurcation for a Delayed SIR Epidemic Model with Logistic Growth

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Yakui Xue ◽  
Tiantian Li
Keyword(s):  
Incidence Rate ◽  
Epidemic Model ◽  
Threshold Value ◽  
Endemic Equilibrium ◽  
Logistic Growth ◽  
Global Dynamics ◽  
Asymptotically Stable ◽  
Sir Epidemic Model ◽  
Globally Asymptotically Stable ◽  
Sir Epidemic

We study a delayed SIR epidemic model and get the threshold value which determines the global dynamics and outcome of the disease. First of all, for anyτ, we show that the disease-free equilibrium is globally asymptotically stable; whenR0<1, the disease will die out. Directly afterwards, we prove that the endemic equilibrium is locally asymptotically stable for anyτ=0; whenR0>1, the disease will persist. However, for anyτ≠0, the existence conditions for Hopf bifurcations at the endemic equilibrium are obtained. Besides, we compare the delayed SIR epidemic model with nonlinear incidence rate to the one with bilinear incidence rate. At last, numerical simulations are performed to illustrate and verify the conclusions.

scholarly journals Calculation and Interpretation of Substrate Assimilation Rates in Microbial Cells Based on Isotopic Composition Data Obtained by nanoSIMS

2021 ◽  
Vol 12 ◽  
Author(s):  
Lubos Polerecky ◽  
Meri Eichner ◽  
Takako Masuda ◽  
Tomáš Zavřel ◽  
Sophie Rabouille ◽  
...  
Keyword(s):  
Cell Division ◽  
Secondary Ion Mass Spectrometry ◽  
Isotopic Labeling ◽  
Threshold Value ◽  
Stable Isotope Probing ◽  
Microbial Cells ◽  
Simplifying Assumptions ◽  
A Cell ◽  
C And N ◽  
Over Time

Stable isotope probing (SIP) combined with nano-scale secondary ion mass spectrometry (nanoSIMS) is a powerful approach to quantify assimilation rates of elements such as C and N into individual microbial cells. Here, we use mathematical modeling to investigate how the derived rate estimates depend on the model used to describe substrate assimilation by a cell during a SIP incubation. We show that the most commonly used model, which is based on the simplifying assumptions of linearly increasing biomass of individual cells over time and no cell division, can yield underestimated assimilation rates when compared to rates derived from a model that accounts for cell division. This difference occurs because the isotopic labeling of a dividing cell increases more rapidly over time compared to a non-dividing cell and becomes more pronounced as the labeling increases above a threshold value that depends on the cell cycle stage of the measured cell. Based on the modeling results, we present formulae for estimating assimilation rates in cells and discuss their underlying assumptions, conditions of applicability, and implications for the interpretation of intercellular variability in assimilation rates derived from nanoSIMS data, including the impacts of storage inclusion metabolism. We offer the formulae as a Matlab script to facilitate rapid data evaluation by nanoSIMS users.

Finding Minimal Infrequent Elements in Multi-Dimensional Data Defined over Partially Ordered Sets and its Applications

2010 ◽  
pp. 98-116
Author(s):  
Khaled M. Elbassioni
Keyword(s):  
Association Rules ◽  
Partially Ordered Set ◽  
Quantitative Data ◽  
Partially Ordered Sets ◽  
Threshold Value ◽  
Ordered Sets ◽  
Time Intervals ◽  
Partially Ordered ◽  
The Given ◽  
Over Time

The authors consider databases in which each attribute takes values from a partially ordered set (poset). This allows one to model a number of interesting scenarios arising in different applications, including quantitative databases, taxonomies, and databases in which each attribute is an interval representing the duration of a certain event occurring over time. A natural problem that arises in such circumstances is the following: given a database D and a threshold value t, find all collections of “generalizations” of attributes which are “supported” by less than t transactions from D. They call such collections infrequent elements. Due to monotonicity, they can reduce the output size by considering only minimal infrequent elements. We study the complexity of finding all minimal infrequent elements for some interesting classes of posets. The authors show how this problem can be applied to mining association rules in different types of databases, and to finding “sparse regions” or “holes” in quantitative data or in databases recording the time intervals during which a re-occurring event appears over time. Their main focus will be on these applications rather than on the correctness or analysis of the given algorithms.

scholarly journals Purifying selection determines the short-term time dependency of evolutionary rates in SARS-CoV-2 and pH1N1 influenza

2021 ◽  
Author(s):  
Mahan Ghafari ◽  
Louis du Plessis ◽  
Jayna Raghwani ◽  
Samir Bhatt ◽  
Bo Xu ◽  
...  
Keyword(s):  
Growth Rates ◽  
High Throughput Sequencing ◽  
Evolutionary Dynamics ◽  
Disease Outbreaks ◽  
Purifying Selection ◽  
Evolutionary Rates ◽  
Logistic Growth ◽  
Time Dependency ◽  
Sampling Window ◽  
Over Time

High throughput sequencing enables rapid genome sequencing during infectious disease outbreaks and provides an opportunity to quantify the evolutionary dynamics of pathogens in near real-time. One difficulty of undertaking evolutionary analyses over short timescales is the dependency of the inferred evolutionary parameters on the timespan of observation. Here, we characterise the molecular evolutionary dynamics of SARS-CoV-2 and 2009 pandemic H1N1 (pH1N1) influenza during the first 12 months of their respective pandemics. We use Bayesian phylogenetic methods to estimate the dates of emergence, evolutionary rates, and growth rates of SARS-CoV-2 and pH1N1 over time and investigate how varying sampling window and dataset sizes affects the accuracy of parameter estimation. We further use a generalised McDonald-Kreitman test to estimate the number of segregating non-neutral sites over time. We find that the inferred evolutionary parameters for both pandemics are time-dependent, and that the inferred rates of SARS-CoV-2 and pH1N1 decline by ~50% and ~100%, respectively, over the course of one year. After at least 4 months since the start of sequence sampling, inferred growth rates and emergence dates remain relatively stable and can be inferred reliably using a logistic growth coalescent model. We show that the time-dependency of the mean substitution rate is due to elevated substitution rates at terminal branches which are 2-4 times higher than those of internal branches for both viruses. The elevated rate at terminal branches is strongly correlated with an increasing number of segregating non-neutral sites, demonstrating the role of purifying selection in generating the time-dependency of evolutionary parameters during pandemics.

scholarly journals Growth and Yield of Tomato Plants in Response to Age of Transplants

1991 ◽  
Vol 116 (3) ◽  
pp. 416-420 ◽  
Author(s):  
Daniel I. Leskovar ◽  
Daniel J. Cantliffe ◽  
Peter J. Stoffella
Keyword(s):  
Lycopersicon Esculentum ◽  
Root Growth ◽  
Shoot Growth ◽  
Total Yield ◽  
Production Costs ◽  
Growth And Yield ◽  
Irrigation Systems ◽  
Tomato Plants ◽  
Chl A ◽  
Over Time

Studies were conducted to evaluate growth of tomato (Lycopersicon esculentum Mill.) transplants in the field in response to age of transplants in Spring and Fall 1989. Transplants were 2 (2W), 3 (3W), 4 (4W), 5 (SW), or 6 (6W) weeks old. Drip and subseepage irrigation were used. In spring, older transplants produced more shoot and root growth up to 2 (T2) weeks after transplanting. At 3 (T3) and 4 (T4) weeks after transplanting, there were no differences between 4W, 5W, and 6W transplants. These trends were independent of irrigation systems. Total yield and early yield were similar for all transplant ages. In fall, shoot growth increased linearly with increasing transplant age at TO, but not thereafter. Chlorophyll a + b increased over time, but no treatment differences were found at T4. At planting, 2W transplants had a higher Chl a: b ratio than older transplants. This difference was reduced at T1 and T2 and became insignificant at T4. These results indicate that no improvement in yields was obtained using the traditional older transplants. Younger transplants might be used to achieve rapid seedling establishment with-minimal transplant production costs.

scholarly journals POSSIBILITIES TO REDUCE POLLUTANT EMISSIONS IN NAVAL DIESEL ENGINES

2020 ◽  
Vol 10 (3) ◽  
pp. 5-9
Author(s):  
Mihail Lucian DUMITRACHE ◽  
Catalin FAITAR
Keyword(s):  
Mathematical Models ◽  
Computer Technology ◽  
Combustion Process ◽  
Difficult Problem ◽  
Production Costs ◽  
Pollutant Emissions ◽  
Mixture Formation ◽  
Complex Process ◽  
Emission Estimation ◽  
Over Time

The combustion process is, by far, the most important and complex process that takes place in engines. Its importance is given by the fact that it provides the flow of energy used in the engine and is the source of all pollutant emissions, the efficiency of the engine being directly influenced by it. The mechanisms of combustion are particularly complex and are not fully known even today, the most difficult problem being the mechanisms of mixture formation and the chemistry of the combustion process. Over time, depending on the evolution of knowledge in the field and computer technology, various mathematical models have been developed, which have. Emission estimation and theoretical verification, in the first phase, of the solutions applicable to in-service enginescould greatly reduce research and production costs, given that there are a variety of engines onboard ships and measurements in operation are very difficult.

scholarly journals Evaluation of substrates on the emergence of "araticum-de-terra-fria" (Annona emarginata (Schltdl.) H. Rainer) Seedlings

2011 ◽  
Vol 33 (2) ◽  
pp. 575-586 ◽  
Author(s):  
Daniel Baron ◽  
Gisela Ferreira ◽  
Carmen Sílvia Fernandes Boaro ◽  
Martha Maria Mischan
Keyword(s):  
Logistic Growth ◽  
Growth Equation ◽  
Seedling Height ◽  
Coconut Fiber ◽  
Initial Development ◽  
Different Types ◽  
Emergence Percentage ◽  
Mean Time ◽  
Determinant Factor ◽  
Over Time

Choosing a substrate is the determinant factor for the seedling producer; thus, the aim of this study was to evaluate the effect of different types of substrates on the emergence of "araticum-de-terra-fria" (Annona emarginata (Schltdl.) H. Rainer) seedlings. The experiment was carried out in a greenhouse and the experimental design was in randomized blocks, with three treatments and five replicates of 72 seeds per plot. The treatments consisted of the following substrates: coconut fiber, vermiculite and Plantmax® Citrus. The number of emerged seedlings was weekly counted for 105 days. Data regarding seedling height were obtained, and the emergence velocity index and mean time, besides total emergence percentage and that over time were calculated. Results from total mean emergence percentage, seedling height, emergence velocity index (EVI), and mean emergence time (MET) were subjected to analysis of variance and means were compared by the Tukey's test at 5% significance. The curves concerning the emergence percentage over time were fit by the logistic growth equation for each treatment and the means of each parameter (A, B, C) were compared by the Duncan's test at 5% significance. The substrates vermiculite led to the highest values of emergence percentage differing from the PlantMax® Citrus, but not of the coconut fiber, however the vermiculite promoted seedling height in a shorter time; therefore, this substrate is recommended for the initial development of "araticum-de-terra-fria" (Annona emarginata (Schltdl.) H. Rainer) seedlings.

Removal of Cu2+ from Aqueous Water by Adsorption onto the Efficient and Recyclable Durian Shell-Derived Activated Carbon

2018 ◽  
Vol 876 ◽  
pp. 46-51 ◽  
Author(s):  
Long Giang Bach ◽  
Dai Viet Nguyen Vo ◽  
Nguyen Duy Trinh ◽  
Van Thi Thanh Ho ◽  
Van Thuan Tran
Keyword(s):  
Activated Carbon ◽  
Langmuir Model ◽  
Raw Material ◽  
P Value ◽  
Optimal Conditions ◽  
Considerable Decrease ◽  
Maximum Capacity ◽  
Monolayer Adsorption ◽  
Confirmation Test ◽  
Order Polynomial

We investigated the use of durian shell-derived activated carbon (DSAC) for the removal of Cu2+. To determine the optimal condition for Cu2+ removal, the response surface methodology (RSM) was used to establish a second-order polynomial model with variables such as Cu2+ concentration (Ci), adsorbent dosage (dDSAC) and pH. With R2 = 0.9847 and P-value < 0.0001, the model was proved to be statistically significant. The RSM based confirmation test revealed that the removal of Cu2+ was maximum (99.6%) at optimal conditions: Ci = 61.6 mg/L, dDSAC = 5.0 g/L and pH = 5.2. Based on calculated R2, data fitness for adsorption isotherms were positioned as follows: Langmuir > Tempkin > Freundlich. In other words, monolayer adsorption was the most favorable behavior with maximum capacity of 76.92 mg/g from Langmuir model. Interestingly, DSAC was reused at least five times without a considerable decrease of Cu2+ removal efficiency. Therefore, durian shell can be used as a highly effective, reusable and promising raw material to fabricate the activated carbon.

scholarly journals Monitoring of Time and Cost Variances of Schedule Using Simple Earned Value Method Indicators

2021 ◽  
Vol 11 (4) ◽  
pp. 1357
Author(s):  
Daniel Przywara ◽  
Adam Rak
Keyword(s):  
Construction Projects ◽  
Organizational Factors ◽  
Housing Development ◽  
Production Costs ◽  
Time Cost ◽  
Earned Value ◽  
Risk Elements ◽  
Construction Contracts ◽  
Family Housing ◽  
Over Time

The Planning and implementation of construction projects are difficult processes and are burdened with many risk elements. The budget spread over time, which is developed on the basis of the schedule, presents the expected distribution of costs throughout the duration of the works, which during the implementation of the project is subject to constant changes resulting from time, cost, and organizational factors. Managing construction contracts requires managers to be able to analyze on an ongoing basis the variances of production costs-from the values calculated in the offer cost estimate and assumed in the Budgeted Cost of Work Scheduled. The article attempts to analyze the emerging time and cost deviations using proprietary time variances from the schedule (T/S) and variances from planned costs (T/C) monitoring, based on simple indicators of the earned value method (EVM). An example of construction of a multi-family housing development was used to study the variances of planned and incurred costs.

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