In December 2019, a novel coronavirus was found in a seafood wholesale market in Wuhan, China. WHO officially named this coronavirus as COVID-19. Since the first patient was hospitalized on December 12, 2019, China has reported a total of 78,824 confirmed CONID-19 cases and 2,788 deaths as of February 28, 2020. Wuhan's cumulative confirmed cases and deaths accounted for 61.1% and 76.5% of the whole China mainland , making it the priority center for epidemic prevention and control. Meanwhile, 51 countries and regions outside China have reported 4,879 confirmed cases and 79 deaths as of February 28, 2020. COVID-19 epidemic does great harm to people's daily life and country's economic development. This paper adopts three kinds of mathematical models, i.e., Logistic model, Bertalanffy model and Gompertz model. The epidemic trends of SARS were first fitted and analyzed in order to prove the validity of the existing mathematical models. The results were then used to fit and analyze the situation of COVID-19. The prediction results of three different mathematical models are different for different parameters and in different regions. In general, the fitting effect of Logistic model may be the best among the three models studied in this paper, while the fitting effect of Gompertz model may be better than Bertalanffy model. According to the current trend, based on the three models, the total number of people expected to be infected is 49852-57447 in Wuhan,12972-13405 in non-Hubei areas and 80261-85140 in China respectively. The total death toll is 2502-5108 in Wuhan, 107-125 in Non-Hubei areas and 3150-6286 in China respetively. COVID-19 will be over p robably in late-April, 2020 in Wuhan and before late-March, 2020 in other areas respectively.

Prediction and analysis of Coronavirus Disease 2019

Bifurcation analysis of two disc dynamos with viscous friction and multiple time delays

The Mathematical theory of the dynamics of biological populations II : based on the proceedings of a conference on the mathematical theory of the dynamics of biological populations held in Oxford, 1st-3rd July, 1980

De novo motif discovery is a difficult computational task. Historically, dedicated algorithms always reported a high percentage of false positives. Their performance did not improve considerably even after they adapted to handle large amounts of chromatin immunoprecipitation sequencing (ChIP-Seq) data. Several studies have advocated aggregating complementary algorithms, combining their predictions to increase the accuracy of the results. This led to the development of ensemble methods. To form a better view on modern ensembles, we review all compound tools designed for ChIP-Seq. After a brief introduction to basic algorithms and early ensembles, we describe the most recent tools. We highlight their limitations and strengths by presenting their architecture, the input options and their output. To provide guidance for next-generation sequencing practitioners, we observe the differences and similarities between them. Last but not least, we identify and recommend several features to be implemented by any novel ensemble algorithm.

/pdf/a-review-of-ensemble-methods-for-de-novo-motif-discovery-in-dx1hqm8oo7.pdf

A review of ensemble methods for de novo motif discovery in ChIP-Seq data

On the Hamilton–Poisson realizations of the integrable deformations of the Maxwell–Bloch equations

A Rikitake type system with one control is defined and some of this geometrical and dynamical properties are pointed out.

A Rikitake type system with one control

Integrable deformations of an integrable case of the Rikitake system are constructed by modifying its constants of motions. Hamilton-Poisson realizations of these integrable deformations are given. Considering two concrete deformation functions, a Hamilton-Poisson approach of the obtained system is presented. More precisely, the stability of the equilibrium points and the existence of the periodic orbits are proved. Furthermore, the image of the energy-Casimir mapping is determined and its connections with the dynamical elements of the considered system are pointed out.

/pdf/hamilton-poisson-realizations-of-the-integrable-deformations-4aw7dew54m.pdf

Hamilton-Poisson Realizations of the Integrable Deformations of the Rikitake System

On some dynamical and geometrical properties of the Maxwell–Bloch equations with a quadratic control

In this paper we consider the 3D real-valued Maxwell-Bloch equations with a parametric control given by $\dot {x}=y+az+byz,\dot {y}=xz,\dot {z}=-xy$
 (
 $a,b\in \mathbb {R}$
 ). We give two Lie-Poisson structures of this system that are related with well-known Lie algebras. Moreover, we construct infinitely many Hamilton-Poisson realizations of this system. We also analyze the stability of the equilibrium points, as well as the existence of periodic orbits. In addition, we emphasize some connections between the energy-Casimir mapping of the considered system and the above-mentioned dynamical elements.

Cristian Lăzureanu

Papers

On the Hamilton–Poisson realizations of the integrable deformations of the Maxwell–Bloch equations

A Rikitake type system with one control

Hamilton-Poisson Realizations of the Integrable Deformations of the Rikitake System

On some dynamical and geometrical properties of the Maxwell–Bloch equations with a quadratic control

On a Hamilton-Poisson Approach of the Maxwell-Bloch Equations with a Control