Continuum Model for River Networks

The effects of erosion, avalanching and random precipitation are captured in a simple stochastic partial differential equation for modelling the evolution of river networks. Our model leads to a self-organized structured landscape and to abstraction and piracy of the smaller tributaries as the evolution proceeds. An algebraic distribution of the average basin areas and a power law relationship between the drainage basin area and the river length are found.Comment: 9 pages, Revtex 3.0, 7 figures in compressed format using uufiles command, to appear in Phys. Rev. Lett., for an hard copy or problems e-mail to [email protected]

The Use of the Terms Flint and Chert

Reference to almost any two text books in geology will show that there are different usages for the terms flint and chert. Perhaps much of the confusion is due to the fact that the origin of these substances is unknown, in which case exact definition at this time would be premature. Whatever the reason it seems advisable to bring out the variability of definition, if for no other purpose than to state a problem without attempting its solution. Blackwelder & Barrows- Elements of Geology, 1911, page 39. Flint is defined as a very compact, dark grey, siliceous rock. Farther on, chert is said to be an impure flint, usually of light color; both occur in limestones

What makes you not a Buddhist? : a preliminary mapping of values

This study sets out to establish which Buddhist values contrasted with or were shared by adolescents from a non-Buddhist population. A survey of attitude toward a variety of Buddhist values was fielded in a sample of 352 non-Buddhist schoolchildren aged between 13 and 15 in London. Buddhist values where attitudes were least positive concerned the worth of being a monk/nun or meditating, offering candles & incense on the Buddhist shrine, friendship on Sangha Day, avoiding drinking alcohol, seeing the world as empty or impermanent and Nirvana as the ultimate peace. Buddhist values most closely shared by non-Buddhists concerned the Law of Karma, calming the mind, respecting those deserving of respect, subjectivity of happiness, welfare work, looking after parents in old age and compassion to cuddly animals. Further significant differences of attitude toward Buddhism were found in partial correlations with the independent variables of sex, age and religious affiliation. Correlation patterns paralleled those previously described in theistic religions. Findings are applied to spiritual, moral, social and cultural development and for the teaching of religious to pupils of no faith adherence. The study recommends that quantitative psychometrics employed to conceptualize Buddhist values by discriminant validity in this study could be extended usefully to other aspects of the study of Buddhism, particularly in quest of validity in the conceptualization of Buddhist identity within specifically Buddhist populations

Unified View of Scaling Laws for River Networks

Scaling laws that describe the structure of river networks are shown to follow from three simple assumptions. These assumptions are: (1) river networks are structurally self-similar, (2) single channels are self-affine, and (3) overland flow into channels occurs over a characteristic distance (drainage density is uniform). We obtain a complete set of scaling relations connecting the exponents of these scaling laws and find that only two of these exponents are independent. We further demonstrate that the two predominant descriptions of network structure (Tokunaga's law and Horton's laws) are equivalent in the case of landscapes with uniform drainage density. The results are tested with data from both real landscapes and a special class of random networks.Comment: 14 pages, 9 figures, 4 tables (converted to Revtex4, PRE ref added

Rainbow structures in locally bounded colorings of graphs

We study approximate decompositions of edge-colored quasirandom graphs into rainbow spanning structures: an edge-coloring of a graph is locallyl-bounded if every vertex is incident to at most l edges of each color, and is (globally) g-boundedif every color appears at most g times. Our results imply the existence of: (1) approximate decompositions of properly edge-colored Kn into rainbow almost-spanning cycles; (2) approximate decompositions of edge-colored Kn into rainbow Hamilton cycles, provided that the coloring is (1-o(1))n2-bounded and locally o(nlog4n)-bounded; and (3) an approximate decomposition into full transversals of any nxn array, provided each symbol appears (1-o(1))n times in total and only o(nlog2n) times in each row or column. Apart from the logarithmic factors, these bounds are essentially best possible. We also prove analogues for rainbow F-factors, where F is any fixed graph. Both (1) and (2) imply approximate versions of the Brualdi-Hollingsworth conjecture on decompositions into rainbow spanning trees.

An Analysis of Plantational Terms : An Addition

Author Institution: Ohio State Universit