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61.
François Gay-Balmaz Darryl D. Holm Vakhtang Putkaradze Tudor S. Ratiu 《Advances in Applied Mathematics》2012
Dendronized polymers consist of an elastic backbone with a set of iterated branch structures (dendrimers) attached at every base point of the backbone. The conformations of such molecules depend on the elastic deformation of the backbone and the branches, as well as on nonlocal (e.g., electrostatic, or Lennard–Jones) interactions between the elementary molecular units comprising the dendrimers and/or backbone. We develop a geometrically exact theory for the dynamics of such polymers, taking into account both local (elastic) and nonlocal interactions. The theory is based on applying symmetry reduction of Hamilton?s principle for a Lagrangian defined on the tangent bundle of iterated semidirect products of the rotation groups that represent the relative orientations of the dendritic branches of the polymer. The resulting symmetry-reduced equations of motion are written in conservative form. 相似文献
62.
63.
In this paper we study the problem of the approximation in
law of the fractional Brownian sheet in the topology of the
anisotropic Besov spaces. We prove the convergence in law of two
families of processes to the fractional Brownian sheet: the
first family is constructed from a Poisson procces in the plane
and the second family is defined by the partial sums of two
sequences of real independent fractional brownian
motions. 相似文献
64.
Oana M. Dragulete Tudor S. Ratiu Miguel Rodrí guez-Olmos 《Transactions of the American Mathematical Society》2007,359(9):4209-4235
This paper studies singular contact reduction for cosphere bundles at the zero value of the momentum map. A stratification of the singular quotient, finer than the contact one and better adapted to the bundle structure of the problem, is obtained. The strata of this new stratification are a collection of cosphere bundles and coisotropic or Legendrian submanifolds of their corresponding contact components.
65.
66.
Tudor Mihai Stoenescu Mingyan Liu Demosthenis Teneketzis 《Mathematical Methods of Operations Research》2007,65(3):389-415
In multirate multicast different users in the same multicast group can receive services at different rates depending on their
own requirements and the congestion level of the network. In this two-part paper we present a general framework for addressing
the optimal rate control problem in multirate multicast where the objective is the maximization of a social welfare function
expressed by the sum of the users’ utility functions. In Part II we present a market based mechanism and an adjustment process
that have the following features. They satisfy the informational constraints imposed by the nature of multirate multicast;
and when they are combined with the results of Part I they result in an optimal solution of the corresponding centralized
multirate multicast problem. 相似文献
67.
We derive simple formulas for the higher-order moments of the quadrature operators operators of a two-field superposition by introducing a new generalized characteristic function depending on two complex variables. Using this formalism we investigate the preservation of higher-order squeezing during weak thermalization of an even coherent state. 相似文献
68.
Oprea TI 《Journal of computer-aided molecular design》2002,16(5-6):325-334
The new drug discovery paradigm is based on high-throughput technologies, both with respect to synthesis and screening. The progression HTS hits lead series candidate drug marketed drug appears to indicate that the probability of reaching launched status is one in a million. This has shifted the focus from good quality candidate drugs to good quality leads. We examined the current trends in lead discovery by comparing MW (molecular weight), LogP (octanol/water partition coefficient, estimated by Kowwin [17]) and LogSw (intrinsic water solubility, estimated by Wskowwin [18]) for the following categories: 62 leads and 75 drugs [11]; compounds in the development phase (I, II, III and launched), as indexed in MDDR; and compounds indexed in medicinal chemistry journals [ref. 20], categorized according to their biological activity. Comparing the distribution of the above properties, the 62 lead structures show the lowest median with respect to MW (smaller) and LogP (less hydrophobic), and the highest median with respect to LogSw (more soluble). By contrast, over 50% of the medicinal chemistry compounds with activities above 1 nanomolar have MW > 425, LogP > 4.25 and LogSw < -4.75, indicating that the reported active compounds are larger, more hydrophobic and less soluble when compared to time-tested quality leads. In the MDDR set, a progressive constraint to reduce MW and LogP, and to increase LogSw, can be observed when examining trends in the developmental sequence: phase I, II, III and launched drugs. These trends indicate that other properties besides binding affinity, e.g., solubility and hydrophobicity, need to be considered when choosing the appropriate leads. 相似文献
69.
Let S be a compact set in R
2. For S simply connected, S is a union of two starshaped sets if and only if for every F finite, F
bdry S, there exist a set G
bdry S arbitrarily close to F and points s, t depending on G such that each point of G is clearly visible via S from one of s, t. In the case where S has at most finitely many components, the necessity of the condition still holds while the sufficiency fails. 相似文献
70.