Listar Matemática por título
Mostrando ítems 211-230 de 232
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The role of SARS-CoV-2 testing on hospitalizations in California
(2021-12-03)The rapid spread of the new SARS-CoV-2 virus triggered a global health crisis, disproportionately impacting people with pre-existing health conditions and particular demographic and socioeconomic characteristics. One of ... -
The role of short-term immigration on disease dynamics: An SIR model with age-structure
(2019-02-18)We formulate an age-structured nonlinear partial differential equation model that features short-term immigration effects in a population. Individuals can immigrate into the population as any of the three stages in the ... -
The set of fiber-bunched cocycles with nonvanishing Lyapunov exponents over a partially hyperbolic map is open
(2018)We prove that the set of fiber-bunched SL(2, R)-valued Hölder cocycles with nonvanishing Lyapunov exponents over a volume preserving, accessible and center-bunched partially hyperbolic diffeomorphism is open. Moreover, we ... -
The significance of physiologically structured models for fish stock dynamics
(1988)The present working document contains the initial papers of a series whose ultimate purpose is to provide a realistic basis for a fresh appraisal of both the surplus production and the dynamic pool approaches to fishery ... -
The Sparse T1 Theorem
(2017)We impose standard T1-type assumptions on a Calderon-Zygmund operator T, and deduce that for bounded compactly supported functions f and g there is a sparse bilinear form B so that |< Tf, g >|; < B(f,g). The proof is short ... -
The Sparse T1 Theorem [presentación]
(2017-03) -
The Stratonovich-Weyl correspondence: A general approach to Wigner functions
(1989)A formalism is proposed for developing phase-space representations of elementary quantum systems under general invariance groups. Several examples are discussed, including the usual Weyl calculus, the Moyal formulation ... -
The Wigner transformation is of finite order
(1987-05)The Wigner integral transformation, which intertwines the twisted product and the composition of kernels, is of order 24. Indeed, it commutes with, and its sixth power equals, the Fourier cotransformation. -
Theta series and number fields: theorems and experiments
(2021-03-01)Let d and n be positive integers and let K be a totally real number field of discriminant d and degree n. We construct a theta series $\theta_K \in \mathcal{M}_{d, n}$ where $\mathcal{M}_{d, n}$ is a space of modular forms ... -
Transmission dynamics of Dengue in Costa Rica: The role of hospitalizations
(2019-12)For decades, dengue virus has caused major problems for public health officials in tropical and subtropical countries around the world. We construct a compartmental model that includes the role of hospitalized individuals ... -
Tres caminos hacia la geometría elemental
(Congreso CANP 2012: "Construcción de Capacidades en Matemáticas y Educación Matemática", 2012-08)La enseñanza de la geometría a nivel preuniversitaria suscita debates sobre su fundamentación, su puesta en práctica y su engranaje con otros áreas de la matemática. Aquí se ofrecen algunas ideas para explorar de qué ... -
Twofold Saddle-Point Formulation of Biot Poroelasticity with Stress-Dependent Diffusion
(2023)We present a new stress/total-pressure formulation for poroelasticity that incorporates the coupling with steady nonlinear diffusion modified by stress. This nonlinear problem is written in mixed-primal form, which combines ... -
Uniform sparse bounds for discrete quadratic phase Hilbert transforms
(2017-09)Consider the discrete quadratic phase Hilbert Transform acting on $\ell^{2}(\mathbb{Z})$ finitely supported functions $$ H^{\alpha} f(n) : = \sum_{m \neq 0} \frac{e^{i\alpha m^2} f(n - m)}{m}. $$ We prove that, ... -
Using generalized logistics regression to forecast population infected by Covid-19
(2020-04-05)In this work, a proposal to forecast the populations using generalized logistics regression curve fitting is presented. This type of curve is used to study population growth, in this case population of people infected ... -
Variations of Hodge Structures of Rank Three k-Higgs Bundles and Moduli Spaces of Holomorphic Triples
(2020)There is an isomorphism between the moduli spaces of σ-stable holomorphic triples and some of the critical submanifolds of the moduli space of k-Higgs bundles of rank three, whose elements (E, ϕk ) correspond to variations ... -
Velocity‑vorticity‑pressure formulation for the Oseen problem with variable viscosity
(2021)We propose and analyse an augmented mixed finite element method for the Oseen equations written in terms of velocity, vorticity, and pressure with non-constant viscosity and homogeneous Dirichlet boundary condition for the ... -
Vertical Transmission in a Two-Strain Model of Dengue Fever
(2014)The role of vertical transmission in vectors has rarely been addressed in the study of dengue dynamics and control, in part because it was not considered a critical population-level factor. In this paper, we apply the ... -
Virtual Coarse Spaces for Irregular Subdomain Decompositions
(2020-10-25)On the other hand, Virtual Element Methods (VEM) [1, 12, 13] allow to handle general polygonal elements. In the case of triangular elements, VEM reduces to the usual FEM. Thus, VEM is a natural choice for constructing space ... -
Wavelet analysis of dengue incidence and its correlation with weather and vegetation variables in Costa Rica
(2021)Dengue represents a serious public health problem in tropical and subtropical regions worldwide. The number of dengue cases and its geographical expansion has increased in recent decades, driven mostly after by social and ... -
Well-posedness and discrete analysis for advection-diffusion-reaction in poroelastic media
(2021)We analyse a PDE system modelling poromechanical processes (formulated in mixed form using the solid deformation, fluid pressure, and total pressure) interacting with diffusing and reacting solutes in the medium. We ...