scholarly journals Switchover phenomenon induced by epidemic seeding on geometric networks

2021 ◽  
Vol 118 (41) ◽  
pp. e2112607118
Author(s):  
Gergely Ódor ◽  
Domonkos Czifra ◽  
Júlia Komjáthy ◽  
László Lovász ◽  
Márton Karsai
Keyword(s):  
Disease Modeling ◽  
Initial Conditions ◽  
Real Life ◽  
Epidemic Spreading ◽  
Final Size ◽  
Initial State ◽  
Underlying Network ◽  
Optimal Configurations ◽  
Insight Into ◽  
Initial Seeding

It is a fundamental question in disease modeling how the initial seeding of an epidemic, spreading over a network, determines its final outcome. One important goal has been to find the seed configuration, which infects the most individuals. Although the identified optimal configurations give insight into how the initial state affects the outcome of an epidemic, they are unlikely to occur in real life. In this paper we identify two important seeding scenarios, both motivated by historical data, that reveal a complex phenomenon. In one scenario, the seeds are concentrated on the central nodes of a network, while in the second one, they are spread uniformly in the population. Comparing the final size of the epidemic started from these two initial conditions through data-driven and synthetic simulations on real and modeled geometric metapopulation networks, we find evidence for a switchover phenomenon: When the basic reproduction number R0 is close to its critical value, more individuals become infected in the first seeding scenario, but for larger values of R0, the second scenario is more dangerous. We find that the switchover phenomenon is amplified by the geometric nature of the underlying network and confirm our results via mathematically rigorous proofs, by mapping the network epidemic processes to bond percolation. Our results expand on the previous finding that, in the case of a single seed, the first scenario is always more dangerous and further our understanding of why the sizes of consecutive waves of a pandemic can differ even if their epidemic characters are similar.

scholarly journals Modeling In-Match Sports Dynamics Using the Evolving Probability Method

2021 ◽  
Vol 11 (10) ◽  
pp. 4429
Author(s):  
Ana Šarčević ◽  
Damir Pintar ◽  
Mihaela Vranić ◽  
Ante Gojsalić
Keyword(s):  
Monte Carlo Simulation ◽  
Statistical Models ◽  
Empirical Bayes ◽  
Hybrid Approach ◽  
Real Life ◽  
Bayes Estimation ◽  
Probability Method ◽  
Specific Nature ◽  
Sport Event ◽  
Insight Into

The prediction of sport event results has always drawn attention from a vast variety of different groups of people, such as club managers, coaches, betting companies, and the general population. The specific nature of each sport has an important role in the adaption of various predictive techniques founded on different mathematical and statistical models. In this paper, a common approach of modeling sports with a strongly defined structure and a rigid scoring system that relies on an assumption of independent and identical point distributions is challenged. It is demonstrated that such models can be improved by introducing dynamics into the match models in the form of sport momentums. Formal mathematical models for implementing these momentums based on conditional probability and empirical Bayes estimation are proposed, which are ultimately combined through a unifying hybrid approach based on the Monte Carlo simulation. Finally, the method is applied to real-life volleyball data demonstrating noticeable improvements over the previous approaches when it comes to predicting match outcomes. The method can be implemented into an expert system to obtain insight into the performance of players at different stages of the match or to study field scenarios that may arise under different circumstances.

scholarly journals Handling Initial Conditions in Vector Fitting for Real Time Modeling of Power System Dynamics

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2471
Author(s):  
Tommaso Bradde ◽  
Samuel Chevalier ◽  
Marco De Stefano ◽  
Stefano Grivet-Talocia ◽  
Luca Daniel
Keyword(s):  
Dynamical Systems ◽  
Power System ◽  
System Dynamics ◽  
Real Time ◽  
Initial Conditions ◽  
Test System ◽  
Initial State ◽  
Power System Dynamics ◽  
Vector Fitting ◽  
Time Modeling

This paper develops a predictive modeling algorithm, denoted as Real-Time Vector Fitting (RTVF), which is capable of approximating the real-time linearized dynamics of multi-input multi-output (MIMO) dynamical systems via rational transfer function matrices. Based on a generalization of the well-known Time-Domain Vector Fitting (TDVF) algorithm, RTVF is suitable for online modeling of dynamical systems which experience both initial-state decay contributions in the measured output signals and concurrently active input signals. These adaptations were specifically contrived to meet the needs currently present in the electrical power systems community, where real-time modeling of low frequency power system dynamics is becoming an increasingly coveted tool by power system operators. After introducing and validating the RTVF scheme on synthetic test cases, this paper presents a series of numerical tests on high-order closed-loop generator systems in the IEEE 39-bus test system.

scholarly journals Modeling of a Real-Life Industrial Reactor for Hydrogenation of Benzene Process

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Mirosław K. Szukiewicz ◽  
Krzysztof Kaczmarski
Keyword(s):  
Catalyst Activity ◽  
Real Life ◽  
Operating Conditions ◽  
Reactor Operation ◽  
Reactor Model ◽  
High Scale ◽  
Industrial Reactor ◽  
Knowledge Based ◽  
Operation Conditions ◽  
Insight Into

A dynamic model of the hydrogenation of benzene to cyclohexane reaction in a real-life industrial reactor is elaborated. Transformations of the model leading to satisfactory results are presented and discussed. Operating conditions accepted in the simulations are identical to those observed in the chemical plant. Under those conditions, some components of the reaction mixture vanish, and the diffusion coefficients of the components vary along the reactor (they are strongly concentration-dependent). We came up with a final reactor model predicting with reasonable accuracy the reaction mixture’s outlet composition and temperature profile throughout the process. Additionally, the model enables the anticipation of catalyst activity and the remaining deactivated catalyst lifetime. Conclusions concerning reactor operation conditions resulting from the simulations are presented as well. Since the model provides deep insight into the process of simulating, it allows us to make knowledge-based decisions. It should be pointed out that improvements in the process run, related to operating conditions, or catalyst application, or both on account of the high scale of the process and its expected growth, will remarkably influence both the profits and environmental protection.

scholarly journals Transformation of Uncertain Linear Systems with Real Eigenvalues into Cooperative Form: The Case of Constant and Time-Varying Bounded Parameters

Algorithms ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 85
Author(s):  
Andreas Rauh ◽  
Julia Kersten
Keyword(s):  
Linear Systems ◽  
Initial Conditions ◽  
A Priori ◽  
Real Life ◽  
Reachability Analysis ◽  
Interval Methods ◽  
Space Representation ◽  
Uncertain Parameters ◽  
Time Varying ◽  
Similarity Transformations

Continuous-time linear systems with uncertain parameters are widely used for modeling real-life processes. The uncertain parameters, contained in the system and input matrices, can be constant or time-varying. In the latter case, they may represent state dependencies of these matrices. Assuming bounded uncertainties, interval methods become applicable for a verified reachability analysis, for feasibility analysis of feedback controllers, or for the design of robust set-valued state estimators. The evaluation of these system models becomes computationally efficient after a transformation into a cooperative state-space representation, where the dynamics satisfy certain monotonicity properties with respect to the initial conditions. To obtain such representations, similarity transformations are required which are not trivial to find for sufficiently wide a-priori bounds of the uncertain parameters. This paper deals with the derivation and algorithmic comparison of two different transformation techniques for which their applicability to processes with constant and time-varying parameters has to be distinguished. An interval-based reachability analysis of the states of a simple electric step-down converter concludes this paper.

scholarly journals Study of the influence of initial-state fluctuations on hydrodynamic simulations

2020 ◽  
Vol 245 ◽  
pp. 06005
Author(s):  
Marcin Słodkowski ◽  
Patryk Gawryszewski ◽  
Dominik Setniewski
Keyword(s):  
Initial Conditions ◽  
Graphics Processing Unit ◽  
Heavy Ion ◽  
Processing Unit ◽  
Initial State ◽  
Final State ◽  
Hydrodynamic Simulation ◽  
Hydrodynamic Simulations ◽  
Cartesian Coordinate ◽  
Ion Collision

In this work, we are focusing on assessing the contribution of the initial-state fluctuations of heavy ion collision in the hydrodynamic simulations. We are trying to answer the question of whether the hydrodynamic simulation retains the same level of fluctuation in the final-state as for the initial stage. In another scenario, the hydrodynamic simulations of the fluctuation drowns in the final distribution of expanding matter. For this purpose, we prepared sufficient relativistic hydrodynamic program to study A+A interaction which allows analysing initial-state fluctuations in the bulk nuclear matter. For such an assumption, it is better to use high spatial resolution. Therefore, we applied the (3+1) dimensional Cartesian coordinate system. We implemented our program using parallel computing on graphics cards processors - Graphics Processing Unit (GPU). Simulations were carried out with various levels of fluctuation in initial conditions using the average method of events coming from UrQMD models. Energy density distributions were analysed and the contribution of fluctuations in initial conditions was assessed in the hydrodynamic simulation.

scholarly journals Use of standard U-bottom and V-bottom well plates to generate neuroepithelial embryoid bodies

2021 ◽  
Author(s):  
David Choy Buentello ◽  
Lina Sophie Koch ◽  
Grissel Trujillo-de Santiago ◽  
Mario Moisés Alvarez ◽  
Kerensa Broersen
Keyword(s):  
Pluripotent Stem Cells ◽  
Disease Modeling ◽  
Cost Effective ◽  
Embryoid Bodies ◽  
High Yield ◽  
Final Size ◽  
Surface Attachment ◽  
Cellular Aggregation ◽  
Centrifugation Step ◽  
Lower Variability

The use of organoids has become increasingly popular recently due to their self-organizing abilities, which facilitate developmental and disease modeling. Various methods have been described to create embryoid bodies (EBs) generated from embryonic or pluripotent stem cells but with varying levels of differentiation success and producing organoids of variable size. Commercial ultra-low attachment (ULA) V-bottom well plates are frequently used to generate EBs. These plates are relatively expensive and not as widely available as standard concave well plates. Here, we describe a cost-effective and low labor-intensive method that creates homogeneous EBs at high yield in standard V- and U-bottom well plates by applying an anti-adherence solution to reduce surface attachment, followed by centrifugation to enhance cellular aggregation. We also explore the effect of different seeding densities, in the range of 1 to 11 ×10 3 cells per well, for the fabrication of neuroepithelial EBs. Our results show that the use of V-bottom well plates briefly treated with anti-adherent solution (for 5 min at room temperature) consistently yields functional neural EBs in the range of seeding densities from 5 to 11×10 3 cells per well. A brief post-seeding centrifugation step further enhances EB establishment. EBs fabricated using centrifugation exhibited lower variability in their final size than their non-centrifuged counterparts, and centrifugation also improved EB yield. The span of conditions for reliable EB production is narrower in U-bottom wells than in V-bottom wells (i.e., seeding densities between 7×10 3 and 11×10 3 and using a centrifugation step). We show that EBs generated by the protocols introduced here successfully developed into neural organoids and expressed the relevant markers associated with their lineages

Charles Lamb's Insight Into the Nature of the Novel

PMLA ◽  
1952 ◽  
Vol 67 (4) ◽  
pp. 375-382
Author(s):  
Charles I. Patterson
Keyword(s):  
Daniel Defoe ◽  
Real Life ◽  
Narrative Fiction ◽  
The Novel ◽  
Prose Fiction ◽  
Critical Essay ◽  
Ample Evidence ◽  
Henry Mackenzie ◽  
External Events ◽  
Insight Into

Charles Lamb exhibited the same genial attitude toward books as toward people; he never expected too much of either, and was therefore seldom disappointed. This whimsical tolerance was especially evident in his reactions to prose fiction. He never went at a novel too seriously—with hammer and tongs, as we say; yet he could distinguish between the enduring works and the pulp. Moreover, he professed to like the same qualities in books as in people: individuality, personality, and even eccentricity. In 1821 he disclaimed a taste for the external events in narrative fiction, contrasting his attitude with that of his sister: “Narrative teases me. I have little concern with the progress of events. She must have a story.... The fluctuations of fortune in fiction ... and almost in real life ... have ceased to interest, or to operate but dully upon me. Out of the way humours and opinions—heads with some diverting twist in them—the oddities of authorship please me most” (ii, 75). There is, however, ample evidence that Lamb read widely in prose fiction and enjoyed the works of the great eighteenth-century masters—Defoe, Richardson, Fielding, and Smollett. He also was acquainted with the writings of Sterne, Goldsmith, Henry Mackenzie, Robert Paltock, Aleman, Cervantes, Jane and Maria Porter, Godwin, Scott, and many figures of less note, including the Minerva Press offerings. As Lamb himself put it, “Defoe was always my darling” (i, 524). In 1829, at the request of his friend Walter Wilson, Lamb wrote a critical essay on Defoe's secondary novels for Wilson's book Memoirs of the Life and Times of Daniel Defoe.4

Sometimes in Reality You Kick the Football: A Conversation with Gabrielle Bell

2018 ◽  
pp. 206-217
Author(s):  
James Yeh
Keyword(s):  
Real Life ◽  
Comic Book ◽  
Insight Into

With clear-eyed honesty and poetic detail, Gabrielle Bell’s comics deliver something that is simultaneously intimate, universal, and very funny. I first encountered Bell and her work in 2009, while I was covering the first-ever Brooklyn Comics and Graphics Festival. Since then I’ve wanted to ask her about rendering real life into art, and to gain some insight into her process, but hadn’t quite been able to gather up the time, or perhaps courage—sometimes, I have found, it’s better to admire from a distance. (Or as I saw in a Charlie Kaufman movie: you are what you love, not what loves you.) And yet the desire for companionship is a resonant theme throughout Bell’s work, so maybe it’s inevitable that I should want to connect with Gabrielle the person, as one connects with Gabrielle the comic-book character....

scholarly journals Redox and essential metal status in the brain of Wistar rats acutely exposed to a cadmium and lead mixture

2020 ◽  
Vol 71 (3) ◽  
pp. 197-204
Author(s):  
Dragana Javorac ◽  
Aleksandra Buha Đorđević ◽  
Milena Anđelković ◽  
Simona Tatović ◽  
Katarina Baralić ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Molecular Mechanisms ◽  
Real Life ◽  
Thiobarbituric Acid ◽  
Control Group ◽  
Special Importance ◽  
Essential Metal ◽  
Cadmium And Lead ◽  
The Brain ◽  
Insight Into

AbstractMost Pb and Cd neurotoxicity studies investigate exposure to either of the toxic metals alone, while data on co-exposure are scarce. The aim of our study was to fill that gap by investigating acute combined effects of Pb and Cd on redox and essential metal status in the brain of Wistar rats. Animals were randomised in four groups of six to eight rats, which received 15 or 30 mg/kg of Cd, 150 mg/kg of Pb, or 150 mg/kg of Pb + 15 mg/kg of Cd by gavage. The fifth, control, group received distilled water only. Co-treatment with Pb and Cd induced significant increase in malondialdehyde (MDA) and thiobarbituric acid-reactive substances (TBARS) compared to control and groups receiving either metal alone. This is of special importance, as MDA presence in the brain has been implicated in many neurodegenerative disorders. The groups did not significantly differ in Zn, Cu, Mn, and Fe brain levels. Our findings highlight the importance of metal mixture studies. Neurotoxicity assessments of single chemicals do not provide a real insight into exposure to mixtures in real life. Further research should look into interactions between these metals to reveal complex molecular mechanisms of their neurotoxicity.

scholarly journals Effect of Spheroidization Annealing on Pearlite Banding

2019 ◽  
Vol 949 ◽  
pp. 40-47 ◽  
Author(s):  
Sergey Guk ◽  
Eva Augenstein ◽  
Maksim Zapara ◽  
Rudolf Kawalla ◽  
Ulrich Prahl
Keyword(s):  
Empirical Model ◽  
Initial Conditions ◽  
The Other ◽  
Experimental Investigations ◽  
Initial State ◽  
Ferritic Matrix ◽  
Other Hand ◽  
Initial States ◽  
Hot Rolled

The present paper deals with the influence of the duration of isothermal spheroidization annealing on the evolution of pearlite bands in various initial states. In this study, two initial conditions of the steel 16MnCrS5 are considered: a) industrially hot-rolled pearlite structures in their ferritic matrix and b) a specifically adjusted microstructure in the lab condition. Based on the experimental investigations and quantitative microstructural analyses, an empirical model for the prediction of pearlite banding within a broad range of annealing durations could be derived. Both, experiment and model, agree that pronounced pearlite bands in the initial state almost disappear after 25 h of spheroidization annealing. On the other hand, a marginal degree of pearlite banding in the initial state increases slightly during annealing. This fact could be explained by inhomogeneous cementite formation inside and outside the primary segregation regions of manganese.

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