Structural Transformation in Pyrolytic Graphite Accompanying Deformation

Pyrolytic graphite deformation and structural transformatio

Tensile Properties of Five Low-Alloy and Stainless Steels Under High-Heating-Rate and Constant-Temperature Conditions

Tensile properties of five low-alloy and stainless steels under high heating rate and constant temperatur

The genotype-phenotype relationship in multicellular pattern-generating models - the neglected role of pattern descriptors

Background: A deep understanding of what causes the phenotypic variation arising from biological patterning processes, cannot be claimed before we are able to recreate this variation by mathematical models capable of generating genotype-phenotype maps in a causally cohesive way. However, the concept of pattern in a multicellular context implies that what matters is not the state of every single cell, but certain emergent qualities of the total cell aggregate. Thus, in order to set up a genotype-phenotype map in such a spatiotemporal pattern setting one is actually forced to establish new pattern descriptors and derive their relations to parameters of the original model. A pattern descriptor is a variable that describes and quantifies a certain qualitative feature of the pattern, for example the degree to which certain macroscopic structures are present. There is today no general procedure for how to relate a set of patterns and their characteristic features to the functional relationships, parameter values and initial values of an original pattern-generating model. Here we present a new, generic approach for explorative analysis of complex patterning models which focuses on the essential pattern features and their relations to the model parameters. The approach is illustrated on an existing model for Delta-Notch lateral inhibition over a two-dimensional lattice. Results: By combining computer simulations according to a succession of statistical experimental designs, computer graphics, automatic image analysis, human sensory descriptive analysis and multivariate data modelling, we derive a pattern descriptor model of those macroscopic, emergent aspects of the patterns that we consider of interest. The pattern descriptor model relates the values of the new, dedicated pattern descriptors to the parameter values of the original model, for example by predicting the parameter values leading to particular patterns, and provides insights that would have been hard to obtain by traditional methods. Conclusion: The results suggest that our approach may qualify as a general procedure for how to discover and relate relevant features and characteristics of emergent patterns to the functional relationships, parameter values and initial values of an underlying pattern-generating mathematical model

Nonlinear wavelength selection in surface faceting under electromigration

We report on the control of the faceting of crystal surfaces by means of surface electromigration. When electromigration reinforces the faceting instability, we find perpetual coarsening with a wavelength increasing as $t^{1/2}$. For strongly stabilizing electromigration, the surface is stable. For weakly stabilizing electromigration, a cellular pattern is obtained, with a nonlinearly selected wavelength. The selection mechanism is not caused by an instability of steady-states, as suggested by previous works in the literature. Instead, the dynamics is found to exhibit coarsening {\it before} reaching a continuous family of stable non-equilibrium steady-states.Comment: 5 pages, 4 figures, submitte

Health impacts of climate change and ozone depletion: an ecoepidemiologic modeling approach.

Anthropogenic climate changes and stratospheric ozone depletion affect human health in various ways. Current mainstream epidemiologic research methods do not appear well adapted to analyze these health impacts, which involve complex systems influenced by human interventions or simpler processes that will take place in the future. This paper discusses a different paradigm for studying the health impacts of global environmental changes and focuses on the development of integrated ecoepidemiologic models using three examples--the effect of climate change on vector-borne diseases, the effect of climate change on thermal-related mortality, and the effects of increasing ultraviolet levels because of ozone depletion on the rates of skin cancer

Subjective evaluation of auditory spatial imagery associated with decorrelated subwoofer signals

Presented at the 8th International Conference on Auditory Display (ICAD), Kyoto, Japan, July 2-5, 2002.Although only a single subwoofer is typically used in two-channel and multichannel stereophonic sound reproduction, the use of two subwoofers enables manipulation of low-frequency interaural crosscorrelation (IACC), and this manipulation is particularly effective in producing variation in auditory spatial imagery. In order to document this variation objectively, a series of listening experiments were executed using a set of stimuli generated at five correlation values and presented in two reproduction modes. Both modes used two subwoofers, but in one of the reproduction modes identical signals were applied to the two subwoofers. The results of both exploratory and confirmatory listening experiments showed that the range of variation in both perceived auditory source width (ASW) and perceived auditory source distance (ASD) is reduced when negatively correlated signals are not reproduced at low frequencies. Global dissimilarity judgments were made for this set of ten stimuli in an exploratory study designed to reveal the salient perceptual dimensions of the stimuli. A subsequent confirmatory study employed a two-alternative forced-choice task in order to determine how identifiably different the stimuli were with respect to the two perceptual attributes revealed in the exploratory study, those two attributes being ASW and ASD. The implications of these findings for loudspeaker-based spatial auditory display are discussed

The multipliers of periodic points in one-dimensional dynamics

It will be shown that the smooth conjugacy class of an $S-$unimodal map which does not have a periodic attractor neither a Cantor attractor is determined by the multipliers of the periodic orbits. This generalizes a result by M.Shub and D.Sullivan for smooth expanding maps of the circle