Search results for "Dimension"
showing 10 items of 2766 documents
Preference for Fractal-Scaling Properties Across Synthetic Noise Images and Artworks
2018
A large number of studies support the notion that synthetic images within a certain intermediate fractal-scaling range possess an intrinsic esthetic value. Interestingly, the fractal-scaling properties that define this intermediate range have also been found to characterize a vast collection of representational, abstract, and graphic art. While some have argued that these statistic properties only serve to maximize the visibility of the artworks’ spatial structure, others argue that they are intrinsically tied to the artworks’ esthetic appeal. In this study, we bring together these two threads of research and make a direct comparison between visual preference for varying fractal-scaling cha…
Sparse relative risk survival modelling
2016
Cancer survival is thought to closed linked to the genimic constitution of the tumour. Discovering such signatures will be useful in the diagnosis of the patient and may be used for treatment decisions and perhaps even the development of new treatments. However, genomic data are typically noisy and high-dimensional, often outstripping the number included in the study. Regularized survival models have been proposed to deal with such scenary. These methods typically induce sparsity by means of a coincidental match of the geometry of the convex likelihood and (near) non-convex regularizer.
Communication between iron(II) building blocks in cooperative spin transition phenomena
2003
[EN] In the present article we discuss the cooperative nature of the spin crossover phenomenon in iron(II) complexes, providing a perspective of the state of the art in this area. The first aspect we discuss is the role of the intermolecular interactions, more precisely the ¿-interactions, in mononuclear complexes. We show that by playing with the nature of the ligands, aliphatic, aromatic, or extended aromatic, it is possible to create stronger cohesive forces and receive a more cooperative response from the compound. In the next step the singular family of bipyrimidine-bridged iron(II) dinuclear compounds is presented as the simplest example of polynuclear spin crossover complexes exhibit…
Some Considerations on 3-D and 2-D Numerical Models for the Assessment of the Stability of Underground Caves
2014
The application of numerical modeling to the analysis of the stability of both natural and man-made underground caves is rapidly increasing due to the availability of powerful numerical codes, that can account for either continuum or discontinuum behavior of the rock masses. Numerical methods allow to overcome traditional methods for cave stability analysis that assume too simplified geometrical, geological and geomechanical conditions. Further, they are also able to assess the potential failure mechanisms of underground systems. On the other hand, the application of numerical methods requires availability of a detailed geo-structural survey of the cave, as well as a proper geomechanical ch…
The effect of plasticity in crumpling of thin sheets
2008
Bridging the gap between theoretical and experimental work to understand the effect of plasticity on the crumpling of thin sheets into a small volume has proved difficult. A realistic numerical model now makes a distinction between elastic and elasto-plastic behaviour. Crumpling a thin sheet of material into a small volume requires energy for creating a network of deformations such as vertices and ridges1,2. Scaling properties of a single elastic vertex3,4,5 or ridge have been analysed theoretically6,7,8, and crumpling of a sheet by numerical simulations1,9,10. Real materials are however elasto-plastic11,12,13,14,15 and large local strains induce irreversible plastic deformations. Hence, a …
Comment on “Effects of different tillage practices on the hydraulic resistance of concentrated flow on the loess plateau in China” by J. Sun et al
2020
Abstract For concentrated flows, which are characterized by small water depth and steep sloping beds, hydraulic conditions different from those typical of streams and rivers occur. In this study a new theoretically deduced flow resistance equation was tested using the experimental data by Sun et al. for three different tilled surfaces (Manual Dibbling, MD, Manual Hoeing, MH, and Contour Drilling, CD). At first, the profile parameter-relationship, which is the relationship between the velocity profile parameter Γ, the channel slope and the flow Froude number, was calibrated using rill flow data by Di Stefano et al. Then, the applicability of this relationship was tested by the measurements o…
A new empirical model for estimating calanchi Erosion in Sicily, Italy
2015
Abstract Calanchi (plural of calanco) are typical badland landforms of the Italian landscape. They consist of dense networks of V-shaped valleys, with a sparse or absent vegetation cover, which frequently develop on unconsolidated or poorly consolidated clayey deposits. In this paper, the dimensional analysis and the incomplete self-similarity theory were used to deduce a model relating the volume of sediments eroded from the calanchi area to a set of geometric attributes of their tributary areas. The morphometric characteristics of 209 calanchi basins were used to calibrate and validate the model. The predictive skill of the model was assessed by calculating the mean square error and the N…
A full‐scale study of Darcy‐Weisbach friction factor for channels vegetated by riparian species
2021
In this article, an open channel flow resistance equation, deduced applying dimensional analysis and incomplete self-similarity condition for the flow velocity distribution, was tested using measurements carried out in a full-scale channel equipped with three types of riparian plants (Salix alba L., Salix caprea L. and Alnus glutinosa L.). In the experimental channel, having banks lined with boulders, the vegetation branches were anchored in a concrete bottom. For each species, the measurements were carried out with plants having different amounts of leaves, different plant density and plant area index. The relationship between the scale factor Γ of the velocity profile and the Froude numbe…
The shell matrix of the freshwater mussel Unio pictorum (Paleoheterodonta, Unionoida). Involvement of acidic polysaccharides from glycoproteins in na…
2007
13 pages; International audience; Among molluscs, the shell biomineralization process is controlled by a set of extracellular macromolecular components secreted by the calcifying mantle. In spite of several studies, these components are mainly known in bivalves from only few members of pteriomorph groups. In the present case, we investigated the biochemical properties of the aragonitic shell of the freshwater bivalve Unio pictorum (Paleoheterodonta, Unionoida). Analysis of the amino acid composition reveals a high amount of glycine, aspartate and alanine in the acid-soluble extract, whereas the acid-insoluble one is rich in alanine and glycine. Monosaccharidic analysis indicates that the in…