Search results for "ASTER"

Artificial mosaics

2005

Art often provides valuable insight that can be applied to technological innovations, especially in the fields of image processing and computer graphics. In this paper we present a method to transform a raster input image into a good-quality mosaic: an “artificial mosaic.” The creation of mosaics of artistic quality is challenging because the tiles that compose a mosaic, typically small polygons, must be packed tightly and yet must follow and emphasize orientations chosen by the artist. The proposed method can reproduce the colors of the original image and emphasize relevant boundaries by placing tiles along edge directions. No user intervention is needed to detect the boundaries: they are …

Giant Quantum Oscillators from Rydberg Atoms: Atomic Coherent States and Their Squeezing from Rydberg Atoms

1989

This paper summarises work since about 1979 by all the authors indicated: RKB is given prominence only because he bears the responsibility for the present paper. All the work has proved relevant to Rydberg atoms. Here we lay particular stress on recent results for squeezing by Rydberg atoms.

Electrical fluctuations in monolayer-protected metal nanoclusters

2008

Abstract Monolayer-protected clusters (MPCs) are formed by a neutral or charged metallic core surrounded by an organic ligand monolayer. We estimate the electric potential fluctuations of a MPC in an electrolyte solution by using the equilibrium fluctuation–dissipation theorem and the non-linear Poisson–Boltzmann equation extended to account for ion penetration in the monolayer. Significant fluctuations are predicted because the MPC capacitance is small (approximately 1 aF). We study also the non-equilibrium case of a MPC sandwiched between two electrodes and estimate the current noise considering the nanocluster as a single electron transistor and using a theoretical approach based on the …

Adatom Island Diffusion on Metal Fcc(100) Surfaces

2001

We study the energetics and atomic mechanisms of diffusion of adatom islands on fcc(100) metal surfaces. For small islands, we perform detailed microscopic calculations using semi-empirical embedded-atom model and glue potentials in the case of Cu and Al, respectively. Combining systematic saddle-point search methods and molecular statics simulations allows us to find all the relevant transition paths for island motion. In particular, we demonstrate that there are novel many-body mechanisms such as internal row shearing which can, in some cases, control the island dynamics. Next, we show how using the master equation formalism, diffusion coefficients for small islands up to about five atoms…

Community Turnover of Wood-Inhabiting Fungi across Hierarchical Spatial Scales

2014

For efficient use of conservation resources it is important to determine how species diversity changes across spatial scales. In many poorly known species groups little is known about at which spatial scales the conservation efforts should be focused. Here we examined how the community turnover of wood-inhabiting fungi is realised at three hierarchical levels, and how much of community variation is explained by variation in resource composition and spatial proximity. The hierarchical study design consisted of management type (fixed factor), forest site (random factor, nested within management type) and study plots (randomly placed plots within each study site). To examine how species richne…

A new mathematical tool for an exact treatment of open quantum system dynamics

2005

A new method to obtain an operatorial exact solution of a wide class of Markovian master equations is presented. Its key point is the existence of a constant of motion partitioning the Hilbert space into finite-dimensional subspaces. The consequent possibility of representing the reduced density operator as a block diagonal matrix is shown. Each “block operator” evolves under the action of a non-unitary operator explicitly derived. Our mathematical approach is illustrated applying it to simple physical systems.

Synthesis of potentially anti-inflammatory IPL576,092-contignasterol and IPL576,092-manoalide hybrids

2004

The synthesis of two potentially anti-inflammatory steroidal hybrid compounds has been accomplished through a 16- and 17-step sequence, respectively, starting from commercially available androst-5-en-3β-ol-17-one. The synthetic strategies are based both on stereoselective side chains elaboration and high yielding functional group transformations.

The Master Equation

2009

Per gli antichi chiostri. Monache e badesse nella Palermo medievale

2020

Il libro inquadra la storia degli otto monasteri femminili fondati a Palermo tra l’XI e il XIV secolo sul piano sociale, economico e culturale, ricostruendo le vicende fondative, il patrimonio, il profilo di monache e badesse. All’atto della fondazione i monasteri ricevettero beni di diversa entità, concentrati nella città e nel territorio di Palermo, che divennero il principale cespite finanziario. Solo la metà dei monasteri ebbe in dotazione un feudo che forniva i prodotti agro-pastorali indispensabili per il fabbisogno interno. La monacazione era considerata la forma di esistenza più alta e perfetta; inoltre, le doti monastiche erano di gran lunga inferiori a quelle matrimoniali e consen…

Cognitive emotion regulation and psychopathology across cultures: A comparison between six European countries

2016

Abstract Use of cognitive emotion regulation strategies in response to stressful life events varies by country, though research has been limited to comparisons between American and Asian cultures. This study aimed to compare six European countries to investigate cross-cultural differences in the use of cognitive strategies and test if the relationship between specific strategies and psychopathology varies across countries. Data arrays were collected from the Netherlands, Hungary, Spain, Italy, Portugal and Germany (N = 1553) and cross-cultural measures of cognitive emotion regulation using the Cognitive Emotion Regulation Questionnaire (CERQ) were included. Measures of depression and anxiet…