Bull Math Biol 2020 05 19;82(6):64. Epub 2020 May 19.

Department of Mathematics and Statistics, University of Victoria, Victoria, Canada.

A stochastic model for Bovine Babesiosis (BB) including ticks, and both juvenile and adult cattle is developed. This model is formulated by a system of continuous-time Markov chains (CTMCs) that is derived based on an extension of the deterministic ordinary differential equation model developed by Saad-Roy et al. (Bull Math Biol 77:514-547, 2015). The nonlinear CTMC model is approximated by a multitype branching process, giving a theoretical estimate of the probability of an outbreak of BB. Unlike the deterministic dynamics where the basic reproduction number is a sharp threshold parameter, the stochastic model indicates that there is always a positive probability of disease extinction within the cattle population. For parameter values from Colombia data, conditional probability distributions are numerically obtained for the time to disease extinction or outbreak, and are found to depend on the host type at the initiation of infection. The models with and without the inclusion of juvenile cattle are compared, and our result highlights that neglecting juvenile bovine in the models may lead to faulty predictions of critical disease statistics: particularly, it may underestimate the risk of infection. Endemic disease prevalence in adult cattle is examined for certain parameter values in the corresponding deterministic model. Notably, with long-lasting immunity, increased tick to juvenile infectivity decreases the proportion of infectious adults.

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http://dx.doi.org/10.1007/s11538-020-00734-x | DOI Listing |

Behav Res Methods 2021 Sep 24. Epub 2021 Sep 24.

KU LEUVEN, Tiensestraat 102 - bus 3713, 3000, Leuven, Belgium.

Computational modeling plays an important role in a gamut of research fields. In affect research, continuous-time stochastic models are becoming increasingly popular. Recently, a non-linear, continuous-time, stochastic model has been introduced for affect dynamics, called the Affective Ising Model (AIM). Read More

Phys Med Biol 2021 Sep 24. Epub 2021 Sep 24.

QST hospital, National Institutes for Quantum and Radiological Science and Technology, Chiba, Chiba, JAPAN.

For hypo-fractionated multi-ion therapy (HFMIT), the stochastic microdosimetric kinetic (SMK) model had been developed to estimate the biological effectiveness of radiation beams with wide linear energy transfer (LET) and dose ranges. The HFMIT will be applied to radioresistant tumors with oxygen-deficient regions. The response of cells to radiation is strongly dependent on the oxygen condition in addition to radiation type, LET and absorbed dose. Read More

Comput Biol Med 2021 Sep 10;138:104858. Epub 2021 Sep 10.

Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, NY, USA.

This study presents a series of numerical simulations for airflow field and particle dispersion and deposition around a mannequin inside a ventilated room. A 3-D airway system of a volunteer subject with a large respiratory system was reconstructed from the nostril inlet to the end of the tracheobronchial tree 4th generation and was integrated into a standing mannequin at the center of a room. The room ventilation system supplied air through a diffuser and expelled air via a damper in three modes. Read More

Acta Biomater 2021 Sep 21. Epub 2021 Sep 21.

Department of Mechanical Engineering, The University of Iowa, Iowa City, IA 52242, USA. Electronic address:

A constitutive model that explicitly considers the gradual recruitment of collagen fibers is applied to investigate the uniaxial properties of human ascending aortic aneurysms. The model uses an effective stretch, which is a continuum scale kinematic variable measuring the true stretch of the tissue, to formulate the fiber stress. The constitutive equation contains two shape parameters characterizing the stochastic distribution of fiber waviness, and two elastic parameters accounting for, respectively, the elastic properties of ground substance and the straightened collagen fibers. Read More

Theor Popul Biol 2021 Sep 21. Epub 2021 Sep 21.

School of Mathematics, University of Minnesota, Twin Cities, MN 55455, USA. Electronic address:

The site frequency spectrum (SFS) is a popular summary statistic of genomic data. While the SFS of a constant-sized population undergoing neutral mutations has been extensively studied in population genetics, the rapidly growing amount of cancer genomic data has attracted interest in the spectrum of an exponentially growing population. Recent theoretical results have generally dealt with special or limiting cases, such as considering only cells with an infinite line of descent, assuming deterministic tumor growth, or taking large-time or large-population limits. Read More

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