Advanced content-based semantic scene analysis and information retrieval: the SCHEMA project

The aim of the SCHEMA Network of Excellence is to bring together a critical mass of universities, research centers, industrial partners and end users, in order to design a reference system for content-based semantic scene analysis, interpretation and understanding. Relevant research areas include: content-based multimedia analysis and automatic annotation of semantic multimedia content, combined textual and multimedia information retrieval, semantic -web, MPEG-7 and MPEG-21 standards, user interfaces and human factors. In this paper, recent advances in content-based analysis, indexing and retrieval of digital media within the SCHEMA Network are presented. These advances will be integrated in the SCHEMA module-based, expandable reference system

Bose-Einstein transition temperature in a dilute repulsive gas

We discuss certain specific features of the calculation of the critical temperature of a dilute repulsive Bose gas. Interactions modify the critical temperature in two different ways. First, for gases in traps, temperature shifts are introduced by a change of the density profile, arising itself from a modification of the equation of state of the gas (reduced compressibility); these shifts can be calculated simply within mean field theory. Second, even in the absence of a trapping potential (homogeneous gas in a box), temperature shifts are introduced by the interactions; they arise from the correlations introduced in the gas, and thus lie inherently beyond mean field theory - in fact, their evaluation requires more elaborate, non-perturbative, calculations. One illustration of this non-perturbative character is provided by the solution of self-consistent equations, which relate together non-linearly the various energy shifts of the single particle levels k. These equations predict that repulsive interactions shift the critical temperature (at constant density) by an amount which is positive, and simply proportional to the scattering length a; nevertheless, the numerical coefficient is difficult to compute. Physically, the increase of the temperature can be interpreted in terms of the reduced density fluctuations introduced by the repulsive interactions, which facilitate the propagation of large exchange cycles across the sample.Comment: two minor corrections, two refs adde

Empirical model for quasi direct current interruption with a convoluted arc

This contribution considers various aspects of a quasi direct current, convoluted arc produced by a magnetic field (B-field) connected in parallel with an RLC circuit that have not been considered in combination. These aspects are the arc current limitation due to the arc convolution, changes in arc resistance due to the B-field and material ablation, and the relative significance of the RLC circuit in producing an artificial current zero. As a result, it has been possible to produce an empirical equation for predicting the current interruption capability in terms of the B-field magnitude and RLC components

Wavelet Decomposition for the Detection and Diagnosis of Faults in Rolling Element Bearings

Condition monitoring and fault diagnosis of equipment and processes are of great concern in industries. Early fault detection in machineries can save millions of dollars in emergency maintenance costs. This paper presents a wavelet-based analysis technique for the diagnosis of faults in rotating machinery from its mechanical vibrations. The choice between the discrete wavelet transform and the discrete wavelet packet transform is discussed, along with the choice of the mother wavelet and some of the common extracted features. It was found that the peak locations in spectrum of the vibration signal could also be efficiently used in the detection of a fault in ball bearings. For the identification of fault location and its size, best results were obtained with the root mean square extracted from the terminal nodes of a wavelet tree of Symlet basis fed to Bayesian classier

What Influences the Diffusion of Grassroots Innovations for Sustainability? Investigating Community Currency Niches

Community action for sustainability is a promising site of socio-technical innovation. Here we test the applicability of co-evolutionary niche theories of innovation diffusion (Strategic Niche Management, SNM) to the context of ‘grassroots innovations’. We present new empirical findings from an international study of 12 community currency niches (such as LETS, time banks, local currencies). These are parallel systems of exchange, designed to operate alongside mainstream money, meeting additional sustainability needs. Our findings confirm SNM predictions that niche-level activity correlates with diffusion success, but we highlight additional or confounding factors, and how niche theories might be adapted to better fit civil-society innovations. In so doing, we develop a model of grassroots innovation niche diffusion which builds on existing work and tailors it to this specific context. The paper concludes with a series of theoretically-informed recommendations for practitioners and policymakers to support the development and potential of grassroots innovations

Elucidating excited state electronic structure and intercomponent interactions in multicomponent and supramolecular systems

Rational design of supramolecular systems for application in photonic devices requires a clear understanding of both the mechanism of energy and electron transfer processes and how these processes can be manipulated. Central to achieving these goals is a detailed picture of their electronic structure and of the interaction between the constituent components. We review several approaches that have been taken towards gaining such understanding, with particular focus on the physical techniques employed. In the discussion, case studies are introduced to illustrate the key issues under consideration

Tuning magnetic hysteresis of electrodeposited Fe 3 O 4

We demonstrate that changes in electrolyte composition and applied potential during aqueous electrodeposition can be used to tune the magnetic hysteresis response of thin-film Fe3O4 (magnetite) on polycrystalline metal substrates. X-ray diffraction data confirmed that magnetite formation in electrolytes containing KCH3COO (0.04–2.0 M) and Fe(SO4)2(NH4)2 (0.01M) required temperatures between 60 and 85 °C, and deposition potentials between −0.300 and −0.575 V or galvanostatic current densities between 50 and 88 μA/cm2. Scanning electron microscopy studies show that magnetite crystallites tend to adopt different habits depending on the electrolyte composition. Room-temperature magnetic hysteresis responses (squareness and coercivity) are dependent upon the crystal habit of deposits, implying that the electrolyte’s acetate concentration influences the magnetic domain structure of the resulting magnetite deposits. Magnetite crystallites grown from electrolytes with low acetate concentrations showed pseudo-single-domain magnetic response, while magnetite grown from acetate-enriched electrolytes showed multidomain magnetic response

Factors that affect proliferation of Salmonella in tomatoes post-harvest: the roles of seasonal effects, irrigation regime, crop and pathogen genotype

MAIN OBJECTIVES: Fresh fruits and vegetables become increasingly recognized as vehicles of human salmonellosis. Physiological, ecological, and environmental factors are all thought to contribute to the ability of Salmonella to colonize fruits and vegetables pre- and post-harvest. The goal of this study was to test how irrigation levels, fruit water congestion, crop and pathogen genotypes affect the ability of Salmonella to multiply in tomatoes post-harvest. EXPERIMENTAL DESIGN: Fruits from three tomato varieties, grown over three production seasons in two Florida locations, were infected with seven strains of Salmonella and their ability to multiply post-harvest in field-grown tomatoes was tested. The field experiments were set up as a two-factor factorial split plot experiment, with the whole-plot treatments arranged in a randomized complete-block design. The irrigation treatment (at three levels) was the whole-plot factor, and the split-plot factor was tomato variety, with three levels. The significance of the main, two-way, and three-way interaction effects was tested using the (type III) F-tests for fixed effects. Mean separation for each significant fixed effect in the model was performed using Tukey's multiple comparison testing procedure. MOST IMPORTANT DISCOVERIES AND SIGNIFICANCE: The irrigation regime per se did not affect susceptibility of the crop to post-harvest proliferation of Salmonella. However, Salmonella grew significantly better in water-congested tissues of green tomatoes. Tomato maturity and genotype, Salmonella genotype, and inter-seasonal differences were the strongest factors affecting proliferation. Red ripe tomatoes were significantly and consistently more conducive to proliferation of Salmonella. Tomatoes harvested in the driest, sunniest season were the most conducive to post-harvest proliferation of the pathogen. Statistically significant interactions between production conditions affected post-harvest susceptibility of the crop to the pathogen. UV irradiation of tomatoes post-harvest promoted Salmonella growth

Gating mechanism of elongating β-ketoacyl-ACP synthases.

Carbon-carbon bond forming reactions are essential transformations in natural product biosynthesis. During de novo fatty acid and polyketide biosynthesis, β-ketoacyl-acyl carrier protein (ACP) synthases (KS), catalyze this process via a decarboxylative Claisen-like condensation reaction. KSs must recognize multiple chemically distinct ACPs and choreograph a ping-pong mechanism, often in an iterative fashion. Here, we report crystal structures of substrate mimetic bearing ACPs in complex with the elongating KSs from Escherichia coli, FabF and FabB, in order to better understand the stereochemical features governing substrate discrimination by KSs. Complemented by molecular dynamics (MD) simulations and mutagenesis studies, these structures reveal conformational states accessed during KS catalysis. These data taken together support a gating mechanism that regulates acyl-ACP binding and substrate delivery to the KS active site. Two active site loops undergo large conformational excursions during this dynamic gating mechanism and are likely evolutionarily conserved features in elongating KSs