University of Trento

About: University of Trento is a education organization based out in Trento, Italy. It is known for research contribution in the topics: Population & Context (language use). The organization has 10527 authors who have published 30978 publications receiving 896614 citations. The organization is also known as: Universitá degli Studi di Trento & Universita degli Studi di Trento.

Brain tissue deforms similarly to filled elastomers and follows consolidation theory

Abstract: Slow, large deformations of human brain tissue—accompanying cranial vault deformation induced by positional plagiocephaly, occurring during hydrocephalus, and in the convolutional development—has surprisingly received scarce mechanical investigation. Since the effects of these deformations may be important, we performed a systematic series of in vitro experiments on human brain tissue, revealing the following features. (i) Under uniaxial (quasi-static), cyclic loading, brain tissue exhibits a peculiar nonlinear mechanical behaviour, exhibiting hysteresis, Mullins effect and residual strain, qualitatively similar to that observed in filled elastomers. As a consequence, the loading and unloading uniaxial curves have been found to follow the Ogden nonlinear elastic theory of rubber (and its variants to include Mullins effect and permanent strain). (ii) Loaded up to failure, the “shape” of the stress/strain curve qualitatively changes, evidencing softening related to local failure. (iii) Uniaxial (quasi-static) strain experiments under controlled drainage conditions provide the first direct evidence that the tissue obeys consolidation theory involving fluid migration, with properties similar to fine soils, but having much smaller volumetric compressibility. (iv) Our experimental findings also support the existence of a viscous component of the solid phase deformation. Brain tissue should, therefore, be modelled as a porous, fluid-saturated, nonlinear solid with very small volumetric (drained) compressibility.

Laser-induced phase explosion: new physical problems when a condensed phase approaches the thermodynamic critical temperature

Abstract: Three kinds of thermal processes may lead to material loss from a laser-irradiated surface: 1) vaporization, 2) normal boiling, and 3) explosive boiling. The latter is equivalent to phase explosion. It is appropriate, at this point, to exclude “subsurface heating”, as there are strong doubts about its existence. The relevance of the three processes depends on the laser pulse duration as well as on the temperature attained in the irradiated zone. We revisit the three thermal processes by noting that: 1) vaporization is not important for the shortest time-scales (<1 ns). 2) Normal boiling is subject to a major kinetic obstacle in the process of bubble diffusion, such motion being sufficiently slow that it will simply not occur for t<100 ns. This is because the value of the bubble diffusion coefficient leads to distances traveled which are atomically small for both 1 ns and 100 ns, and for both T=Tm and T=2Tm, with Tm being the melting temperature. 3) Phase explosion, notwithstanding the unfavorable time-scale (1–100 ns) advocated by Martynyuk, as carefully analyzed in this paper, is found to be the most efficient mechanism in the ablation process when looking at thermal processes. Here it should be recognized that a new field in the physics of condensed matter may be emerging when looking at physical properties near the thermodynamic critical temperature, Ttc. In fact, laser irradiation experiments probably represent a unique tool to investigate matter under extreme thermodynamic conditions and on very short time-scales (ps or fs).

Unconventional Phased Array Architectures and Design Methodologies—A Review

Abstract: The proliferation of wireless services is driving innovative phased array solutions that are able to provide better cost/performance tradeoffs. In this context, the use of irregular array architectures provides a viable solution. This paper reviews and highlights some of the most recent advances in this field, including clustered, thinned, sparse, and time-modulated arrays, and their proposed design methodologies.

Organizational Learning: Diverging Communities of Practice?

Abstract: This article provides an overview of current debates in the field of organizational learning through the device of examining key `divergencies' within the literature. Clear divergencies are noted in two areas: first, between the practitioner literature which is primarily engaged in creating learning organizations and the academic literature which is engaged in the study of learning processes in organizations; and, second, in the views of both academics and practitioners about the nature and essence of organizational learning. In addition, but with somewhat less significance, divergencies are noted in the preferred ways of investigating and researching into organizational learning, and ways of improving the ability of organizations to learn. The article then identifies power as an issue that has received limited attention in the literature, but which appears to underlie many of the above divergencies.

Strain-level microbial epidemiology and population genomics from shotgun metagenomics

Abstract: Identifying microbial strains and characterizing their functional potential is essential for pathogen discovery, epidemiology and population genomics. We present pangenome-based phylogenomic analysis (PanPhlAn; http://segatalab.cibio.unitn.it/tools/panphlan), a tool that uses metagenomic data to achieve strain-level microbial profiling resolution. PanPhlAn recognized outbreak strains, produced the largest strain-level population genomic study of human-associated bacteria and, in combination with metatranscriptomics, profiled the transcriptional activity of strains in complex communities.