14,358 research outputs found
More on the Cohort-Component Model of Population Projection in the Context of HIV/AIDS: A Leslie Matrix Representation and New Estimates
This article presents an extension of the cohort component model of population projection (CCMPP) first formulated by Heuveline that is capable of modeling a population affected by HIV. We extend this work by developing the Leslie matrix representation of the CCMPP that greatly facilitates implementation of the model for parameter estimation and projecting. The Leslie matrix also contains information about the stable tendencies of the corresponding population, such as the stable age distribution and time to stability. We validate our reformulation of the model by comparing parameter estimates obtained through maximum likelihood and bootstrap methods to those presented by Heuveline.Africa, AIDS/HIV, cohort component method, estimation, incidence, Leslie matrices, model, prevalence
Comparing Powers of Edge Ideals
Given a nontrivial homogeneous ideal , a
problem of great recent interest has been the comparison of the th ordinary
power of and the th symbolic power .
This comparison has been undertaken directly via an exploration of which
exponents and guarantee the subset containment
and asymptotically via a computation of the resurgence , a number for
which any guarantees .
Recently, a third quantity, the symbolic defect, was introduced; as
, the symbolic defect is the minimal number of generators
required to add to in order to get .
We consider these various means of comparison when is the edge ideal of
certain graphs by describing an ideal for which .
When is the edge ideal of an odd cycle, our description of the structure
of yields solutions to both the direct and asymptotic containment
questions, as well as a partial computation of the sequence of symbolic
defects.Comment: Version 2: Revised based on referee suggestions. Lemma 5.12 was added
to clarify the proof of Theorem 5.13. To appear in the Journal of Algebra and
its Applications. Version 1: 20 pages. This project was supported by Dordt
College's undergraduate research program in summer 201
Mathematical approaches to scale degrees and harmonic functions in analytical dialogue
Published versio
Extending General Equilibrium to the Tariff Line: U.S. Dairy in the Doha Development Agenda
International Relations/Trade,
A contact process with mutations on a tree
Consider the following stochastic model for immune response. Each pathogen
gives birth to a new pathogen at rate . When a new pathogen is born,
it has the same type as its parent with probability . With probability
, a mutation occurs, and the new pathogen has a different type from all
previously observed pathogens. When a new type appears in the population, it
survives for an exponential amount of time with mean 1, independently of all
the other types. All pathogens of that type are killed simultaneously. Schinazi
and Schweinsberg (2006) have shown that this model on behaves rather
differently from its non-spatial version. In this paper, we show that this
model on a homogeneous tree captures features from both the non-spatial version
and the version. We also obtain comparison results between this model
and the basic contact process on general graphs
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