scholarly journals Novel mathematical approach to covid-19 studies with reproduction-like number and acceleration parameter

2021 ◽  
Author(s):  
Eckhard Rebhan
Keyword(s):  
Exponential Growth ◽  
Reproduction Number ◽  
Analytical Form ◽  
Mathematical Approach ◽  
Acceleration Parameter ◽  
Infection Dynamics ◽  
Least Squares Fit ◽  
The World ◽  
Close Relationship

Abstract To study the progression of a pandemic, the cumulative case numbers Zn, assigned to discrete time steps tn, are transferred into a continuously differentiable function Z(t) by means of a best least squares fit. In this setting, a reproduction- like number is introduced which is easily applicable to many different situations due to its handy analytical form. It can be understood as a cross between a volatile in- stantaneous reproduction number and the more robust effective reproduction number commonly used. Starting from it, a further quantity, termed acceleration parameter, is introduced, which facilitates a more differentiated characterization of the infection dynamics. In particular, it allows to determine precisely when the limit to exponential growth is reached and exceeded. In this context, the frequently encountered equaliza- tion of dangerous and exponential growth of the infection numbers is shown to be rather misleading. Hence it is extensively studied how different kinds of growth can be correctly described. In many situations exponential growth is just a timeless tran- sient between sub- and super-exponential growth, and, quite generally, it proves to be much more complex than commonly assumed. It turned out useful to incorporate the incidence as a further epidemiological indicator, and for comparison purposes the effective reproduction number is also included. A close relationship is found between the two. In addition, the incidence is used for calculating the trace that the progres- sion of the pandemic leaves behind on a plain spanned by itself and the acceleration parameter. This plane can be divided into a dangerous area, where the pandemic is uncontrollable, and a safer area that must be the target of mitigation efforts. At present, many countries and the world as a whole are mired in the dangerous area. The latter was chosen as an example for all applications to the covid-19 pandemic.

scholarly journals New reproduction number and acceleration parameter introduced and applied to COVID-19

2021 ◽  
Author(s):  
Eckhard Rebhan
Keyword(s):  
Exponential Growth ◽  
Reproduction Number ◽  
Analytical Form ◽  
Precise Determination ◽  
Acceleration Parameter ◽  
Infection Dynamics ◽  
The World

Abstract To characterize the progression of a pandemic, a well interpretable reproduction number is introduced which is easily applicable to many different situations due to its handy analytical form. On the basis of its derivation it can be understood as a cross between a volatile instantaneous reproduction number and the more robust effective reproduction number commonly used. Starting from it, a further quantity, termed acceleration parameter, is introduced, which facilitates a more differentiated characterization of the infection dynamics. In particular, it enables the precise determination of when the limit to exponential growth is reached and exceeded. A variety of possible developments is examined, including linear and exponential growth of the infection numbers as well as sub- and super-exponential growth. It turned out useful to incorporate the incidence as a further epidemiological indicator. It is used for calculating the trace that the progression of the pandemic leaves behind on a plain spanned by itself and the acceleration parameter. This plane can be divided into a dangerous area, where the pandemic becomes uncontrollable, and a safer area that must be the target of mitigation efforts. At present, many countries and the world as a whole are mired in the dangerous area.

scholarly journals Estimation of the Basic Reproduction Number of SARS-CoV-2 in Bangladesh Using Exponential Growth Method

2020 ◽  
Author(s):  
Riaz Mahmud ◽  
H. M. Abrar Fahim Patwari
Keyword(s):  
Standard Deviation ◽  
Basic Reproduction Number ◽  
Exponential Growth ◽  
Generation Time ◽  
Reproduction Number ◽  
First Case ◽  
The World ◽  
Growth Method ◽  
Novel Coronavirus ◽  
The Basic Reproduction Number

Objectives: In December 2019, a novel coronavirus (SARS-CoV-2) outbreak emerged in Wuhan, Hubei Province, China. Soon, it has spread out across the world and become an ongoing pandemic. In Bangladesh, the first case of novel coronavirus (SARS-CoV-2) was detected on March 8, 2020. Since then, not many significant studies have been conducted to understand the transmission dynamics of novel coronavirus (SARS-CoV-2) in Bangladesh. In this study, we estimated the basic reproduction number R0 of novel coronavirus (SARS-CoV-2) in Bangladesh. Methods: The data of daily confirmed cases of novel coronavirus (SARS-CoV-2) in Bangladesh and the reported values of generation time of novel coronavirus (SARS-CoV-2) for Singapore and Tianjin, China, were collected. We calculated the basic reproduction number R0 by applying the exponential growth (EG) method. Epidemic data of the first 76 days and different values of generation time were used for the calculation. Results: The basic reproduction number R0 of novel coronavirus (SARS-CoV-2) in Bangladesh is estimated to be 2.66 [95% CI: 2.58-2.75], optimized R0 is 2.78 [95% CI: 2.69-2.88] using generation time 5.20 with a standard deviation of 1.72 for Singapore. Using generation time 3.95 with a standard deviation of 1.51 for Tianjin, China, R0 is estimated to be 2.15 [95% CI: 2.09-2.20], optimized R0 is 2.22 [95% CI: 2.16-2.29]. Conclusions: The calculated basic reproduction number R0 of novel coronavirus (SARS-CoV-2) in Bangladesh is significantly higher than 1, which indicates its high transmissibility and contagiousness.

scholarly journals Modified SIR-model applied to covid-19, similarity solutions and projections to further development

2020 ◽  
Author(s):  
Eckhard Rebhan
Keyword(s):  
Exponential Growth ◽  
Reproduction Number ◽  
Analytic Form ◽  
Sir Model ◽  
Similarity Solutions ◽  
Acceleration Parameter ◽  
Similarity Transformations ◽  
Number Dynamics ◽  
Simple Analytic Form ◽  
Net Reproduction

The SIR-model is adapted to the covid-19 pandemic through a modification that consists in making the basic reproduction number variable. Independent of it, another reproduction number is introduced, which is defined similarly to the usual net reproduction number. Due to its simple analytic form, it enables a clear interpretation for all values. A further parameter, provisionally called acceleration parameter, is introduced and applied, which enables a more differentiated characterization of the infection number dynamics. By a variable transformation the 3 equations of the modified SIR-model can be reduced to 2. The latter are solved up to ordinary integrations. The solutions are evaluated for current situations, yielding a pretty good match with the data reported. Encouraged by this, a variety of possible future developments is examined, including linear and exponential growth of the infection numbers as well as sub- and super-exponential growth. In particular, the behavior of the two reproduction numbers and the acceleration parameter is studied, which in some cases leads to surprising results. With regard to the number of unreported infections it is shown, that from the solution for a special one solutions for others can be derived by similarity transformations.

Impact of Globalisation on Pandemics: A comparative study on SARS and Covid-19 (Preprint)

2020 ◽  
Author(s):  
Johann Johann And Devika
Keyword(s):  
Comparative Analysis ◽  
Comparative Study ◽  
Descriptive Analysis ◽  
Qualitative Comparative Analysis ◽  
Global Scale ◽  
Global Level ◽  
Economic Stability ◽  
The Past ◽  
The World ◽  
Close Relationship

BACKGROUND Since November 2019, Covid - 19 has spread across the globe costing people their lives and countries their economic stability. The world has become more interconnected over the past few decades owing to globalisation and such pandemics as the Covid -19 are cons of that. This paper attempts to gain deeper understanding into the correlation between globalisation and pandemics. It is a descriptive analysis on how one of the factors that was responsible for the spread of this virus on a global scale is globalisation. OBJECTIVE - To understand the close relationship that globalisation and pandemics share. - To understand the scale of the spread of viruses on a global scale though a comparison between SARS and Covid -19. - To understand the sale of globalisation present during SARS and Covid - 19. METHODS A descriptive qualitative comparative analysis was used throughout this research. RESULTS Globalisation does play a significant role in the spread of pandemics on a global level. CONCLUSIONS - SARS and Covid - 19 were varied in terms of severity and spread. - The scale of globalisation was different during the time of SARS and Covid - 19. - Globalisation can be the reason for the faster spread in Pandemics.

scholarly journals The absence of the caffeine synthase gene is involved in the naturally decaffeinated status of Coffea humblotiana, a wild species from Comoro archipelago

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nathalie Raharimalala ◽  
Stephane Rombauts ◽  
Andrew McCarthy ◽  
Andréa Garavito ◽  
Simon Orozco-Arias ◽  
...  
Keyword(s):  
Wild Species ◽  
Illegitimate Recombination ◽  
Recombination Mechanism ◽  
Comparative Analyses ◽  
Robusta Coffee ◽  
Caffeine Synthase ◽  
The World ◽  
Decaffeinated Coffee ◽  
Chromosome Level

AbstractCaffeine is the most consumed alkaloid stimulant in the world. It is synthesized through the activity of three known N-methyltransferase proteins. Here we are reporting on the 422-Mb chromosome-level assembly of the Coffea humblotiana genome, a wild and endangered, naturally caffeine-free, species from the Comoro archipelago. We predicted 32,874 genes and anchored 88.7% of the sequence onto the 11 chromosomes. Comparative analyses with the African Robusta coffee genome (C. canephora) revealed an extensive genome conservation, despite an estimated 11 million years of divergence and a broad diversity of genome sizes within the Coffea genus. In this genome, the absence of caffeine is likely due to the absence of the caffeine synthase gene which converts theobromine into caffeine through an illegitimate recombination mechanism. These findings pave the way for further characterization of caffeine-free species in the Coffea genus and will guide research towards naturally-decaffeinated coffee drinks for consumers.

scholarly journals Theoretical and Empirical Characterization of Water as a Factor: Examples and Related Issues with the World Trade Model

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 459
Author(s):  
Ignacio Cazcarro ◽  
Albert E. Steenge
Keyword(s):  
World Trade ◽  
Low Cost ◽  
Virtual Water ◽  
Considerable Change ◽  
Water Research ◽  
Trade Model ◽  
The World ◽  
Main Model ◽  
Selection Of

This article originates from the theoretical and empirical characterization of factors in the World Trade Model (WTM). It first illustrates the usefulness of this type of model for water research to address policy questions related to virtual water trade, water constraints and water scarcity. It also illustrates the importance of certain key decisions regarding the heterogeneity of water and its relation to the technologies being employed and the prices obtained. With regard to WTM, the global economic input–output model in which multiple technologies can produce a “homogeneous output”, it was recently shown that two different mechanisms should be distinguished by which multiple technologies can arise, i.e., from “technology-specific” or from “shared” factors, which implies a mechanism-specific set of prices, quantities and rents. We discuss and extend these characterizations, notably in relation to the real-world characterization of water as a factor (for which we use the terms technology specific, fully shared and “mixed”). We propose that the presence of these separate mechanisms results in the models being sensitive to relatively small variations in specific numerical values. To address this sensitivity, we suggest a specific role for specific (sub)models or key choices to counter unrealistic model outcomes. To support our proposal we present a selection of simulations for aggregated world regions, and show how key results concerning quantities, prices and rents can be subject to considerable change depending on the precise definitions of resource endowments and the technology-specificity of the factors. For instance, depending on the adopted water heterogeneity level, outcomes can vary from relatively low-cost solutions to higher cost ones and can even reach infeasibility. In the main model discussed here (WTM) factor prices are exogenous, which also contributes to the overall numerical sensitivity of the model. All this affects to a large extent our interpretation of the water challenges, which preferably need to be assessed in integrated frameworks, to account for the main socioeconomic variables, technologies and resources.

scholarly journals Estimating COVID-19 cases infected with the variant alpha (VOC 202012/01): an analysis of screening data in Tokyo, January-March 2021

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Hiroaki Murayama ◽  
Taishi Kayano ◽  
Hiroshi Nishiura
Keyword(s):  
Confidence Interval ◽  
Growth Model ◽  
Exponential Growth ◽  
Reproduction Number ◽  
Hypergeometric Distribution ◽  
Actual Number ◽  
Growth Data ◽  
Exponential Growth Model

Abstract Background In Japan, a part of confirmed patients’ samples have been screened for the variant of concern (VOC), including the variant alpha with N501Y mutation. The present study aimed to estimate the actual number of cases with variant alpha and reconstruct the epidemiological dynamics. Methods The number of cases with variant alpha out of all PCR confirmed cases was estimated, employing a hypergeometric distribution. An exponential growth model was fitted to the growth data of variant alpha cases over fourteen weeks in Tokyo. Results The weekly incidence with variant alpha from 18–24 January 2021 was estimated at 4.2 (95% confidence interval (CI): 0.7, 44.0) cases. The expected incidence in early May ranged from 420–1120 cases per week, and the reproduction number of variant alpha was on the order of 1.5 even under the restriction of contact from January-March, 2021, Tokyo. Conclusions The variant alpha was predicted to swiftly dominate COVID-19 cases in Tokyo, and this has actually occurred by May 2021. Devising the proposed method, any country or location can interpret the virological sampling data.

Area Studies and Desire: Towards a Genealogy

1997 ◽  
Vol 1 (1) ◽  
pp. 52-65
Author(s):  
Hye-Joon Yoon
Keyword(s):  
Chinese Culture ◽  
Geographical Area ◽  
Academic Research ◽  
Past Century ◽  
Area Studies ◽  
Western Area ◽  
The World ◽  
38Th Parallel ◽  
The One

Area studies, as a newly fashionable field of academic research, needs to recognize its less likely precedents if it is going to secure for itself a fresh start. The question of “desire” is relevant here because it indicates the less value-free aspects in its genealogy. As shown in Emma Bovary's embellished representation of Paris at her provincial home, an understanding of an area often reflects the particular needs and desires of the one who understands that area. Such restricted and restricting views of an area repeats itself outside the world of literary fictions, as is shown by the example of Guizot's picture of Europe in which his own country is given a privileged place as the very center of Western civilization itself. An instructive case showing the thin line between the projected desire of one who strives to know a geographical area and the scientific purity of the labor itself is further offered by Napoleon Bonaparte's heavy reliance on Orientalist scholarship in his invasion of Egypt. Moving further east from Egypt to China, we witness the denigrating remarks on China made by the great German thinkers of the past century, Hegel and Weber. Although their characterization of Chinese culture could find echoes in unbiased empirical research, they reveal all the same the trace of Europeans' desire to affirm their superiority over the supposedly inferior and false civilization of the East. Similarly, the Americans who divided the Korean peninsular at the 38th Parallel, with unquestioning confidence in their knowledge of the area and in the justice of their action, rightfully deserve their place in the tradition of Western area studies of serving the needs to dominate, control and exploit an objectified overseas territory. He assumed that words had kept their meaning, that desires still pointed in a single direction, and that ideas retained their logic; and he ignored the fact that the world of speech and desires has known invasions, struggles, plundering, disguises, ploys. From these elements, however, genealogy retrieves an indispensable restraint: it must record the singularity of events outside of any monotonous finality; it must seek them in the most unpromising places, in what we tend to feel is without history—in sentiments, love, conscience, instincts; it must be sensitive to their recurrence, not in order to trace the gradual curve of their evolution, but to isolate the different scenes where they engaged in different roles. — Michel Foucault, “Nietzsche, Genealogy, History” (Foucault 139–40).

scholarly journals Characterization of Two Novel Polyomaviruses of Birds by Using Multiply Primed Rolling-Circle Amplification of Their Genomes

2006 ◽  
Vol 80 (7) ◽  
pp. 3523-3531 ◽  
Author(s):  
Reimar Johne ◽  
Walter Wittig ◽  
Daniel Fernández-de-Luco ◽  
Ursula Höfle ◽  
Hermann Müller
Keyword(s):  
Rolling Circle Amplification ◽  
Large Tumor ◽  
Rolling Circle ◽  
Reading Frame ◽  
Field Samples ◽  
Close Relationship ◽  
Avian Polyomavirus ◽  
Avian Group ◽  
Pyrrhula Pyrrhula

ABSTRACT Polyomaviruses are small nonenveloped particles with a circular double-stranded genome, approximately 5 kbp in size. The mammalian polyomaviruses mainly cause persistent subclinical infections in their natural nonimmunocompromised hosts. In contrast, the polyomaviruses of birds—avian polyomavirus (APV) and goose hemorrhagic polyomavirus (GHPV)—are the primary agents of acute and chronic disease with high mortality rates in young birds. Screening of field samples of diseased birds by consensus PCR revealed the presence of two novel polyomaviruses in the liver of an Eurasian bullfinch (Pyrrhula pyrrhula griseiventris) and in the spleen of a Eurasian jackdaw (Corvus monedula), tentatively designated as finch polyomavirus (FPyV) and crow polyomavirus (CPyV), respectively. The genomes of the viruses were amplified by using multiply primed rolling-circle amplification and cloned. Analysis of the FPyV and CPyV genome sequences revealed a close relationship to APV and GHPV, indicating the existence of a distinct avian group among the polyomaviruses. The main characteristics of this group are (i) involvement in fatal disease, (ii) the existence of an additional open reading frame in the 5′ region of the late mRNAs, and (iii) a different manner of DNA binding of the large tumor antigen compared to that of the mammalian polyomaviruses.

scholarly journals Characterization of three soybean landraces resistant to Asian soybean rust disease

2020 ◽  
Vol 40 (6) ◽  
Author(s):  
Luciano Nobuhiro Aoyagi ◽  
Yukie Muraki ◽  
Naoki Yamanaka
Keyword(s):  
Susceptible Variety ◽  
Soybean Rust ◽  
Resistance Locus ◽  
Chromosome 6 ◽  
Phakopsora Pachyrhizi ◽  
Rust Disease ◽  
Asian Soybean Rust ◽  
The World ◽  
Trait Locus

Abstract Phakopsora pachyrhizi is an obligatory biotrophic fungus that causes Asian soybean rust (ASR) disease. ASR control primarily involves chemical control and the use of resistant soybean cultivars carrying an Rpp (resistance to P. pachyrhizi) gene. This study aimed to characterize the ASR resistance of three soybean Asian landraces. By screening the world core collection (WC) of soybean, which consists of 80 varieties, three landraces were identified in Southeast Asia as resistant to ASR. Genetic mapping using the F2 population derived from a cross with an ASR-susceptible variety, BRS 184, indicated that KS 1034 (WC2) has ASR resistance conferred by a single dominant resistance gene, mapped on chromosome 18, in the same region where Rpp1 was mapped previously. The BRS 184 × WC61 (COL/THAI/1986/THAI-80) F2 population, on the other hand, showed an ASR resistance locus mapped by quantitative trait locus analysis on chromosome 6, in the region where the resistance conferred by PI 416764 Rpp3 resides, with a logarithm of the odds score peak at the same position as the marker, Satt079, while the BRS 184 × WC51 (HM 39) population showed the resistance to ASR allocated between Satt079 and Sat_263 markers, also in the region where Rpp3 was mapped previously. Both WC51 and WC61 have the same infection profile as FT-2 and PI 462312 when tested against the same ASR isolate panel. These three WCs can be used in MAS programs for introgression of Rpp1 and Rpp3 and the development of ASR-resistant cultivars in the breeding program.

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