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Medicine and Health Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

2009

SelectedWorks

Cristina Lanzas

Articles 1 - 2 of 2

Full-Text Articles in Medicine and Health Sciences

Development Of A Mechanistic Model To Represent The Dynamics Of Particle Flow Out Of The Rumen And To Predict Rate Of Passage Of Forage Particles In Dairy Cattle., S Seo, Cristina Lanzas, L O. Tedeschi, A Pell, D G. Fox Aug 2009

Development Of A Mechanistic Model To Represent The Dynamics Of Particle Flow Out Of The Rumen And To Predict Rate Of Passage Of Forage Particles In Dairy Cattle., S Seo, Cristina Lanzas, L O. Tedeschi, A Pell, D G. Fox

Cristina Lanzas

A mechanistic and dynamic model was developed to represent physiological aspects of particle dynamics in the reticulo-rumen (RR) and to predict rate of passage out of the RR (Kp) of forage particles quantitatively. The model consists of 2 conceptual pools with 3 spatial compartments of particles; the compartment the particle enters is based on functional specific gravity (FSG). The model assumes 2 major pressure gradient-driven flows of particles out of the RR through the reticulo-omasal orifice between 2 consecutive primary reticular contractions. One is associated with the second phase of primary reticular contraction and involves propulsion of particles in the …


Modeling On-Farm Escherichia Coli O157:H7 Population Dynamics, P Ayscue, Cristina Lanzas, R Ivanek, Y T. Grohn May 2009

Modeling On-Farm Escherichia Coli O157:H7 Population Dynamics, P Ayscue, Cristina Lanzas, R Ivanek, Y T. Grohn

Cristina Lanzas

Escherichia coli O157:H7 is a potentially fatal foodborne pathogen with a putative reservoir for human infection in feedlot cattle. In order to more effectively identify targets for intervention strategies, we aimed to (1) assess the role of various feedlot habitats in E. coli O157:H7 propagation and (2) provide a framework for examining the relative contributions of animals and the surrounding environment to observed pathogen dynamics. To meet these goals we developed a mathematical model based on an ecological metapopulation framework to track bacterial population dynamics inside and outside the host. We used E. coli O157:H7 microbiological and epidemiological literature to …