Search results for "Mechanism"

Feeding ecology and chewing mechanics in hoofed mammals: 3D tribology of enamel wear.

2013

11 pages; International audience; Large herbivorous mammals have evolved chewing systems capable of processing a large variety of structurally diverse foods. Three-dimensional (3D) surface texture parameters are applied to investigate wear mechanisms related to tooth morphology, food source, and chewing dynamics. We tested 46 industrial 3D surface texture parameters for their capability to robustly indicate specific biomechanics in two grazing (Blue Wildebeest and Grevy's Zebra) and two browsing (Giraffe and Black Rhinoceros) ungulate mammals. These species inhabit sub-Saharan Africa and represent foregut and hindgut fermenters. The results did not indicate a wavelength threshold that can c…

Kindergarten teachers adjust their teaching practices in accordance with children's academic pre-skills

2011

This study examined the extent to which kindergarten children’s academic pre‐skills are associated with their teachers’ subsequent teaching practices. The pre‐skills in reading and math of 1268 children (655 boys, 613 girls) were measured in kindergarten in the fall. A pair of trained observers used the Classroom Assessment Scoring System instrument to observe 49 kindergarten teachers on their emotional support, classroom organisation and instructional support in kindergarten in the spring. The results of the multilevel modelling showed that low levels of academic pre‐skills in kindergarten classrooms in the fall predicted high classroom quality in the classrooms later on. The results sugge…

Unemployment and Migration: Does Moving Help?

2002

Abstract The migration behaviour of the unemployed in Finland is analysed in terms of the causal effectof moving on individual employment status. In 1994, 17 percent of the labour force wasunemployed and the unemployment rate exhibited a very slow decline in 1994–1996. Overhalf of those who were unemployed at the end of 1994 were still unemployed two years later.The propensity to find a job is somewhat greater among migrants. However, the positive effectof moving diminishes once other personal characteristics are accounted for. Moreover, whencontrolling for endogenous migrant selectivity, an insignificant or even negative effect onemployment status emerges. This indicates that the relatively …

Accumulation and self-organization in hydrofracturetransport of fluids

2003

Abstract Propagation of “mobile hydrofractures” is one of several mechanisms to transport fluids. Analogue experiments show howthis transport mechanism is intimately linked with accumulation, by stepwise mergers of fluid batches. Analogue experiments and numerical modelling indicate that such stepwise transport and accumulation may lead to the establishment of a self-organised critical state.

Mechanics and self-organization in tissue development

2021

Self-organization is an all-important feature of living systems that provides the means to achieve specialization and functionality at distinct spatio-temporal scales. Herein, we review this concept by addressing the packing organization of cells, the sorting/compartmentalization phenomenon of cell populations, and the propagation of organizing cues at the tissue level through traveling waves. We elaborate on how different theoretical models and tools from Topology, Physics, and Dynamical Systems have improved the understanding of self-organization by shedding light on the role played by mechanics as a driver of morphogenesis. Altogether, by providing a historical perspective, we show how i…

Anti-inflammatory glycoterpenoids from Scrophularia auriculata.

2000

The activity of the four glycoterpenoids: two saponins, verbascosaponin A and verbascosaponin, and two iridoids, scropolioside A and scrovalentinoside, isolated from Scrophularia auriculata ssp. pseudoauriculata, were studied in different models of acute and chronic inflammation. Both saponins significantly inhibited the mouse paw edema induced by carrageenan and ear edema induced by single and multiple doses of 12-O-tetradecanoylphorbol 13-acetate (TPA). Verbascosaponin A showed a potency twice as high as that of indomethacin in the acute TPA model. Verbascosaponin A and scropolioside A were active after a long latency period against ethyl phenylpropiolate edema, as are glucocorticoids. Wh…

Interaction Mechanism of Humans in a Cyber-Physical Environment

2015

The research initiative “Industrie 4.0” (I4.0) of the high-tech strategy announced by the German government targets the deployment of a cyber-physical system (CPS) in production and logistics. Such CPS-based environments are characterized by an increasing number of heterogeneous intelligent autonomous and communicating artifacts tightly integrated with humans. Thus, the human’s role will become a composite factor (“man-in-the-mesh”) for this future CPS environment, playing more than just a simple role inside the control loop. This paper investigates the need of a robust communication between CPS and humans, which includes a clear semantic of the exchanged information. For this purpose, a me…

Chronic myeloid leukaemia-derived exosomes promote tumour growth through an autocrine mechanism

2014

The influence of substitution in the quinoxaline nucleus on 1,3-dipolar cycloaddition reactions

2013

The reaction mechanism of 1,3-dipolar cycloadditions of both symmetric and unsymmetric benzo-condensed diazines with a nitrilimine dipole, to give two different mono- and bis-cycloadducts, in tetrahydrofuran (THF) solution, was studied by DFT calculatio ns. The results obtained show that each 1,3-dipolar cycloaddition reaction always proceeds by a two steps mechanism, in which the first intermediate shows only one covalent bond between the beta carbon of the nitrilimine and the aromatic nitrogen of the diazine molecule. The structure and energy content of the two transition states of the two cycloaddition steps, in the case of the unsymmetric benzo-condensed diazine, nicely explains why the…

A contribution to a seismotectonic model of the hinge zone between northern Sicily and southern Tyrrhenian by some seismological and structural const…

2013

An integrated research on the hinge zone between northern Sicily and its Tyrrhenian off-shore has been carried out, by means of structural, seismological and statistical analyses. The main structural features of the area are represented by both NWSE to W–E striking right-lateral and N–S to NE-SW striking leftlateral fault systems, responsible of uplifting (restraining) and subsiding (releasing) zones. Within this hinge zone the seismicity is mainly located between 10 and 20 km of depth and clustered according to the orientation of the outcropping fault systems. The brittle strain partitioning related to a right-lateral simple shear zone has been reconstructed in the onshore sector, while in…