Several studies have been performed to evaluate the desertification in Iran andother countries which led to present national and regional models. One of them is IMDPAmodel. This model was used as a case study in Taraz Nahid, Saveh, Iran. In this study, fivefactors including climate, soil, vegetation, irrigation, and socioeconomic ones wereevaluated. According to the region conditions for each c...

[1] The presence of valley networks (VN) on Mars suggests that early Mars was warmer and wetter than present. However, detailed geomorphic analyses of individual networks have not led to a consensus regarding their origin. An additional line of evidence can be provided by the global pattern of dissection on Mars, but the currently available global map of VN, compiled from Viking images, is inco...

The problem of finding the most probable explanation to a designated set of variables given partial evidence (the MAP problem) is a notoriously intractable problem in Bayesian networks, both to compute exactly and to approximate. It is known, both from theoretical considerations and from practical experience, that low tree-width is typically an essential prerequisite to efficient exact computat...

The importance of geographic isolation in speciation has been debated since the 19th century. Since the beginning of the 20th century, the consensus has been that most speciation involves divergence in allopatry. This consensus was based largely on decades of observations by naturalists and verbal arguments against speciation without isolation. Recent attempts to quantify the importance of allo...

We describe a method for numerical construction of a symplectic map for particle propagation in a general accelerator lattice. The generating function of the map is obtained by integrating the Hamilton-Jacobi equation as an initial-value problem on a finite time interval. Given the generating function, the map is put in explicit form by means of a Fourier inversion technique. We give an example...

Conditions are given for a Ck map T to be a Newton map, that is, the map associated with a differentiable real-valued function via Newton’s method. For finitely differentiable maps and functions, these conditions are only necessary, but in the smooth case, i.e. for k = ∞ , they are also sufficient. The characterisation rests upon the structure of the fixed point set of T and the value of the de...

Quantum baker‘s map is a model of chaotic system. We study quantum dynamics for the quantum baker’s map. We use the Schack and Caves symbolic description of the quantum baker‘s map. We find an exact expression for the expectation value of the time dependent position operator. A relation between quantum and classical trajectories is investigated. Breakdown of the quantum-classical correspondence...

A method is presented for estimating the background at a given location on a sky map by interpolating the estimated background from a set of concentric annuli which surround this location. If the background is nonuniform but smoothly varying, this method provides a more accurate (though less precise) estimate than can be obtained with a single annulus. Several applications of multi-annulus back...

The number of distinct maps with a single vertex and valence d is computed for any value of d. The question of what precisely is meant by a map can be answered in several different ways. We enumerate 16 different types of objects where each type is obtained by selecting whether the object is a pre-map or a map, is oriented or general, whether the underlying graph or pre-graph is signed or unsig...