A lattice model that displays anomalous density behavior and exhibits a reentrant spinodal is developed. This model is solved in the mean field approximation and the interrelation between density maxima and the reentrance of the spinodal is explicitly demonstrated. The limits of stability of the liquid phase are obtained at positive as well as negative pressures, and the nature of the limits of...

Using precision measurements of tracer particle trajectories in a two-dimensional fluid flow producing chaotic mixing, we directly measure the time-dependent stretching field. This quantity, previously available only numerically, attains local maxima along lines that coincide with the stable and unstable manifolds of hyperbolic fixed points of Poincaré maps. Contours of a passive impurity field...

We propose a principal curve tracing algorithm that uses the gradient and the Hessian of a given density estimate. Curve definition requires the local smoothness of data density and is based on the concept of subspace local maxima. Tracing of the curve is handled through the leading eigenvector where fixed-step updates are used. We also propose an image segmentation algorithm based on the origi...

There is a sequence of random numbers x1, x2 . . . , xn and so on. Numbers are independent of each other, but all numbers are from the same continuous distribution. If xi−1 < xi > xi+1, then xi is a local maximum. Here, we show that the probability mass function (PMF) fm(d) of distances d between local maxima is non-parametric and the same for any probability distribution of random numbers in t...

Idealized dynamical theories that employ a convective quasi-equilibrium (QE) treatment for the diabatic effects of moist convection have been used to explain the location, intensity, and intraseasonal evolution of monsoons. This paper examines whether observations of Earth’s regional monsoons are consistent with the assumption of QE. It is shown here that in local summer climatologies based on ...

Cancer cell transformation is often accompanied by a modification of their viscoelastic properties. When capturing the stress-to-strain response of primary chronic myelogenous leukemia (CML) cells, from two data sets of CD34+ hematopoietic cells isolated from healthy and leukemic bone marrows, we show that the mean shear relaxation modulus increases upon cancer transformation. This stiffening o...

A maximum stable set in a graph G is a stable set of maximum cardinality. S is a local maximum stable set if it is a maximum stable set of the subgraph of G spanned by S ∪N(S), where N(S) is the neighborhood of S. One theorem of Nemhauser and Trotter Jr. [10], working as a useful sufficient local optimality condition for the weighted maximum stable set problem, ensures that any local maximum st...

We compare two forms of hybrid genetic search. The rst uses Lamarckian evolution, while the second uses a related method where local search is employed to change the tness of strings, but the acquired improvements do not change the genetic encoding of the individual. The latter search method exploits the Baldwin eeect. By modeling a simple genetic algorithm we show that functions exist where si...

In this paper we present a new heuristic solution method for two-dimensional nesting problems. It is based on a simple local search scheme in which the neighborhood is any horizontal or vertical translation of a given polygon from its current position. To escape local minima we apply the meta-heuristic method Guided Local Search. The strength of our solution method comes from a new algorithm wh...

Variable neighborhood search (VNS) [4, 5] is a metaheuristic for solving optimization problems based on a simple principle: systematic changes of neighborhoods within the search, both in the descent to local minima and in the escape from the valleys which contain them. VNS applications have been numerous and successful. Many extensions have been made, mainly to be able to solve large problem in...