Results 21 to 30 of about 487,972 (266)
4 open, 2020 The work proposes a new general nonlinear mathematical model describing the social process of two-level assimilation taking into account quadratic members of self-restriction of population growth of three sides.
Chilachava Temur, Pochkhua George
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Vibration of the Liénard Oscillator with Quadratic Damping and Constant Excitation
MathematicsIn this paper, the Liénard oscillator with nonlinear deflection, quadratic damping, and constant excitation is considered. In general, there is no analytic solution for the Liénard equation.
Livija Cveticanin +3 more
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Elementary first integrals of differential equations [PDF]
Transactions of the American Mathematical Society, 1981 It is not always possible and sometimes not even advantageous to write the solutions of a system of differential equations explicitly in terms of elementary functions. Sometimes, though, it is possible to find elementary functions which are constant on solution curves, that is, elementary first integrals. These first integrals allow one to occasionally
Prelle, M. J., Singer, M. F.
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The Global Dynamics of the Painlevé–Gambier Equations XVIII, XXI, and XXII
MathematicsIn this paper, we describe the global dynamics of the Painlevé–Gambier equations numbered XVIII: x″−(x′)2/(2x)−4x2=0, XXI: x″−3(x′)2/(4x)−3x2, and XXII: x″−3(x′)2/(4x)+1=0.
Jie Li, Jaume Llibre
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Exact Solutions for Strong Nonlinear Oscillators with Linear Damping
MathematicsThis paper presents the derivation of an exact solution for a damped nonlinear oscillator of arbitrary order (both integer and non-integer). A coefficient relationship was defined under which such a solution exists. The analytical procedure was developed
Livija Cveticanin
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The FirstINTEGRALAGN Catalog [PDF]
The Astrophysical Journal, 2006 We present the first INTEGRAL AGN catalog, based on observations performed from launch of the mission in October 2002 until January 2004. The catalog includes 42 AGN, of which 10 are Seyfert 1, 17 are Seyfert 2, and 9 are intermediate Seyfert 1.5. The fraction of blazars is rather small with 5 detected objects, and only one galaxy cluster and no star ...
Beckmann, V. +3 more
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Distributions, First Integrals and Legendrian Foliations
Bulletin of the Brazilian Mathematical Society, New Series, 2022 We study germs of holomorphic distributions with "separated variables'. In codimension one, a well know example of this kind of distribution is given by the canonical contact structure on $\mathbb{P}^{2m+1}$ . Another example is the Darboux distribution, which gives the normal local form of any contact structure.
Luza, Maycol Falla, Rosas, Rudy
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Communication and Language Profiles of Children Treated for Posterior Fossa Brain Tumors
Pediatric Blood &Cancer, EarlyView.ABSTRACT Background Cognitive and language deficits are frequently reported sequelae of posterior fossa brain tumors (PFBT). Typically, delayed onset impedes prompt assessment and early intervention. This has devastating implications for quality of life.
Zara Sved +4 more
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Pediatric Blood &Cancer, EarlyView.ABSTRACT Background The HIT network was established in 2000 to create a population‐based structure aiming to improve survival rates and reduce late effects for children with central nervous system (CNS) tumors by conducting comprehensive clinical trials.
Stefan Rutkowski +59 more
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A Note on the First Integrals of Vector Fields with Integrating Factors and Normalizers
Symmetry, Integrability and Geometry: Methods and Applications, 2012 We prove a sufficient condition for the existence of explicit first integrals for vector fields which admit an integrating factor. This theorem recovers and extends previous results in the literature on the integrability of vector fields which are volume
Jaume Llibre, Daniel Peralta-Salas
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