Brown University

About: Brown University is a education organization based out in Providence, Rhode Island, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 35778 authors who have published 90896 publications receiving 4471489 citations. The organization is also known as: brown.edu & Brown.

Ordinary and Delay Differential Equations

Abstract: Ordinary differential equations on singular spaces, Z. Bartosiewicz stability in delayed neural networks, J. Belair a condition on multi-existence of periodic solutions for a differential delay equation, Y. Cao control of global economic growth - will the centre hold?, E.N. Chukwu asymptotic behaviour of the Titchmarsh-Weyl coefficient for a coupled second order system, S.L. Clark stability problems for systems of nuclear reactors, C. Cordoneanu comparison theorems for disconjugate linear differential equations, M. Gaudenzi oscillation results for higher order nonlinear neutral delay equations with periodic coefficients, J.R. Graef, M.K. Grammatikopoulos and P.W. Spikes an implicit differential equation related to epidemic models, K.P. Hadeler and R. Shonkwiler the relationship between stability under disturbances and uniform stability in a periodic integrodifferential equation, Y. Hamaya on the asymptotic stability of the equilibrium of the damped oscillator, L. Hatvani on higher order nonlinear differential-difference equations, U. An Der Heiden vector field approximations flow homogencity, H. Hermes hopf bifurcation for a differential-difference equation from climate modeling, G. Hetzer shock layer behaviour for vector boundary value problems, S.J. Kirschvink properties of solutions of nth order equations, W.A.J. Kosmala small solutions to BVP's at resonance with nonhomogeneous nonlinearity, L. Lefton vibrational control of time delay systems, B. Lehman bifurcation set and compound eyes in a perturbed cubic Hamiltonian system, J. Li and Z. Lu gevrey character of formal solutions of nonlinear differential equations, X. Liu finite-difference schemes having the correct linear stability properties for all finite step-sizes, R.E. Mickens evolution of surface functionals and differential equations, Y. Li and J.S. Muldowney some remarks on stability properties in functional differential equations with infinite delay, S. Murakami and T. Yoshizawa periodic orbits of the Froeschle's map, A. Olvera and C. Vargas rotated vector fields, global families of limit cycles and Hilbert's 16th problem, L.M. Perko green's matrices and disconjugacy of a vector difference equation, A. Peterson the poincare manifold for the general case of a planar flow, W. Rivera hopf bifurcation in a class of ODE systems related to climate modeling, P.G. Schmidt on second order two point boundary value problems at resonance, M. Hihnala and S. Seikkala separatrix connections of quadratic gradient vector fields, D.S. Shafer. Part contents.

Pre-colonial Ethnic Institutions and Contemporary African Development

Abstract: We investigate the role of deeply rooted pre-colonial ethnic institutions in shaping comparative regional development within African countries. We combine information on the spatial distribution of ethnicities before colonization with regional variation in contemporary economic performance, as proxied by satellite images of light density at night. We document a strong association between pre-colonial ethnic political centralization and regional development. This pattern is not driven by differences in local geographic features or by other observable ethnic-specific cultural and economic variables. The strong positive association between pre-colonial political complexity and contemporary development also holds within pairs of adjacent ethnic homelands with different legacies of pre-colonial political institutions.

Type 1 Interferons and the Virus-Host Relationship: A Lesson in Détente

Abstract: The interface between an infectious agent and its host represents the ultimate battleground for survival: The microbe must secure a niche for replication, whereas the host must limit the pathogen's advance. Among the host's arsenal of antimicrobial factors, the type 1 interferons (IFNs) induce potent defense mechanisms against viruses and are key in the host-virus standoff. Viruses have evolved multiple tricks to avoid the immediate antiviral effects of IFNs and, in turn, hosts have adapted use of this innate cytokine system to galvanize multiple additional layers of immune defense. The plasticity that exists in these interactions provides us with a lesson in detente.

Kinetics of biopolymerization on nucleic acid templates.

Abstract: The kinetics of biopolymerization on nucleic acid templates is discussed. The model introduced allows for the simultaneous synthesis of several chains, of a given type, on a common template, e.g., the polyribosome situation. Each growth center [growing chain end plus enzyme(s)] moves one template site at a time, but blocks L adjacent sites. Solutions are found for the probability nj(t) that a template has a growing center that occupies the sites j — L + 1,…, j at time t. Two special sets of solutions are considered, the uniform-density solutions, for which nj(t) = n, and the more general steady-state solutions, for which dnj(t)/dt = 0. In the uniform-density case, there is an upper bound to the range of rates of polymerization that can occur. Corresponding to this maximum rate, there is one uniform solution. For a polymerization rate less than this maximum, there are two uniform solutions that give the same rate. In the steady-state case, only L = 1 is discussed. For a steady-state polymerization rate less than the maximum uniform-density rate, the steady-state solutions consist of either one or two regions of nearly uniform density, with the density value(s) assumed in the uniform region(s) being either or both of the uniform-density solutions corresponding to that polymerization rate. For a steady-state polymerization rate equal to or slightly larger than the maximum uniform-density rate, the steady-state solutions are nearly uniform to the single uniform-density solution for the maximum rate. The boundary conditions (rate of initiation and rate, of release of completed chains from the template) govern the choice among the possible solutions, i.e., determine the region(s) of uniformity and the value(s) assumed in the uniform region(s).

Stability of Intelligence from Preschool to Adolescence: The Influence of Social and Family Risk Factors

Abstract: Intelligence scores of children in a longitudinal study were assessed at 4 and 13 years and related to social and family risk factors. A multiple environmental risk score was calculated for each child by counting the number of high-risk conditions from 10 risk factors: mother's behavior, mother's developmental beliefs, mother's anxiety, mother's mental health, mother's educational attainment, family social support, family size, major stressful life events, occupation of head of household, and disadvantaged minority status. Multiple risk scores explained one-third to one-half of IQ variance at 4 and 13 years. The stability between 4- and 13-year environmental risk scores (r = .77) was not less than the stability between between 4- and 13-year IQ scores (r = .72). Effects remained after SES and race, or maternal IQ, were partialled; multiple risk was important in longitudinal prediction, even after prior measurement of child IQ was accounted for; the pattern of risk was less important than the total amount of risk present in the child's context.