Comment

This report describes a fourth order tensor defined on projective spaces which can be used for the representation of medium-level features, e.g., one or more oriented segments. The tensor has one part which describes what type of local structures are present in a region, and one part which describes where they are located. This information can be used, e.g., to represent multiple orientations, corners, and line-endings. The tensor can be defined for arbitrary signal dimension, but the presentation focuses on the properties of the fourth order tensor for the case of 2D and 3D image data. A method for estimating the proposed tensor representation by means of simple computations directly from the structure tensor is presented. Given a simple matrix representation of the tensor, it can be shown that there is a direct correspondence between the number of oriented segments and the rank of the matrix provided that the number of segments is three or less. The \publication also presents techniques for extracting information about the oriented segments which the tensor represent. Finally, it shown that a small set of coefficients can be computed from the proposed tensor which are invariant to changes of the coordinate system

Evidence for prelocalization of cytoplasmic factors affecting gene activation in early embryogenesis

Differentiation begins early in embryogenesis as different genes become active in different cells. Within the closed system of the early embryo, equal genomes thus direct the creation of diverse cell types. Though the nuclei of these cells contain complete copies of the same genome,(1,2) the nucleoplasmic and cytoplasmic environments of these genomes are not the same, as a result of the distribution of cleavage nuclei into diverse areas of egg cytoplasm early in the cleavage process. In some cases the fate of these nuclei, i.e., the type of differentiated cell to which they or their descendants give rise, has been seen to depend on the area of cytoplasm in which they come to lie

Investigation into high-temperature corrosion in a large-scale municipal waste-to-energy plant

High-temperature corrosion in the superheater of a large-scale waste-to-energy plant was investigated. A comparison of nickel-/iron-based alloys and austenitic stainless steel probes placed in the furnace demonstrated that temperature and particle deposition greatly influence corrosion. Nickel-based alloys performed better than the other metal alloys, though an aluminide coating further increased their corrosion resistance. Sacrificial baffles provided additional room for deposit accumulation, resulting in vigorous deposit-induced corrosion. Computational modelling (FLUENT code) was used to simulate flow characteristics and heat transfer. This study has shown that the use of aluminide coatings is a promising technique for minimising superheater corrosion in such facilities. (C) 2010 Elsevier Ltd. All rights reserved

SBML models and MathSBML

MathSBML is an open-source, freely-downloadable Mathematica package that facilitates working with Systems Biology Markup Language (SBML) models. SBML is a toolneutral,computer-readable format for representing models of biochemical reaction networks, applicable to metabolic networks, cell-signaling pathways, genomic regulatory networks, and other modeling problems in systems biology that is widely supported by the systems biology community. SBML is based on XML, a standard medium for representing and transporting data that is widely supported on the internet as well as in computational biology and bioinformatics. Because SBML is tool-independent, it enables model transportability, reuse, publication and survival. In addition to MathSBML, a number of other tools that support SBML model examination and manipulation are provided on the sbml.org website, including libSBML, a C/C++ library for reading SBML models; an SBML Toolbox for MatLab; file conversion programs; an SBML model validator and visualizer; and SBML specifications and schemas. MathSBML enables SBML file import to and export from Mathematica as well as providing an API for model manipulation and simulation

Linearized large signal modeling, analysis, and control design of phase-controlled series-parallel resonant converters using state feedback

This paper proposes a linearized large signal state-space model for the fixed-frequency phase-controlled series-parallel resonant converter. The proposed model utilizes state feedback of the output filter inductor current to perform linearization. The model combines multiple-frequency and average state-space modeling techniques to generate an aggregate model with dc state variables that are relatively easier to control and slower than the fast resonant tank dynamics. The main objective of the linearized model is to provide a linear representation of the converter behavior under large signal variation which is suitable for faster simulation and large signal estimation/calculation of the converter state variables. The model also provides insight into converter dynamics as well as a simplified reduced order transfer function for PI closed-loop design. Experimental and simulation results from a detailed switched converter model are compared with the proposed state-space model output to verify its accuracy and robustness

The enemy within:designing a cell-based gameplay system for cancer education

This paper outlines the design and preliminary evaluation of The Enemy Within, a browser-based game produced to raise awareness of the nature of cancer as a progressive disease. Aimed at high school and young adult audiences, the ambition with the game is to make visible to players the myriad ways in which healthy cells can mutate and ultimately inherit hallmarks of cancer, whilst also demonstrating how both real-world behaviours and underlying genetics impact both positively and negatively on cell health

Structure of a new dense amorphous ice

The detailed structure of a new dense amorphous ice, VHDA, is determined by isotope substitution neutron diffraction. Its structure is characterized by a doubled occupancy of the stabilizing interstitial location that was found in high density amorphous ice, HDA. As would be expected for a thermally activated unlocking of the stabilizing "interstitial," the transition from VHDA to LDA (low-density amorphous ice) is very sharp. Although its higher density makes VHDA a better candidate than HDA for a physical manifestation of the second putative liquid phase of water, as for the HDA case, the VHDA to LDA transition also appears to be kinetically controlled

Special Issue Paper

An exploratory data analysis of the temperature fluctuations in a spreading fir

Suppression of allergic airway inflammation by helminth-induced regulatory T cells

Allergic diseases mediated by T helper type (Th) 2 cell immune responses are rising dramatically in most developed countries. Exaggerated Th2 cell reactivity could result, for example, from diminished exposure to Th1 cell–inducing microbial infections. Epidemiological studies, however, indicate that Th2 cell–stimulating helminth parasites may also counteract allergies, possibly by generating regulatory T cells which suppress both Th1 and Th2 arms of immunity. We therefore tested the ability of the Th2 cell–inducing gastrointestinal nematode Heligmosomoides polygyrus to influence experimentally induced airway allergy to ovalbumin and the house dust mite allergen Der p 1. Inflammatory cell infiltrates in the lung were suppressed in infected mice compared with uninfected controls. Suppression was reversed in mice treated with antibodies to CD25. Most notably, suppression was transferable with mesenteric lymph node cells (MLNC) from infected animals to uninfected sensitized mice, demonstrating that the effector phase was targeted. MLNC from infected animals contained elevated numbers of CD4(+)CD25(+)Foxp3(+) T cells, higher TGF-β expression, and produced strong interleukin (IL)-10 responses to parasite antigen. However, MLNC from IL-10–deficient animals transferred suppression to sensitized hosts, indicating that IL-10 is not the primary modulator of the allergic response. Suppression was associated with CD4(+) T cells from MLNC, with the CD4(+)CD25(+) marker defining the most active population. These data support the contention that helminth infections elicit a regulatory T cell population able to down-regulate allergen induced lung pathology in vivo