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"Bray, Dennis"
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The Body of the Artist, in the Body of Christ: Toward a Theology of the Embodied Arts
One insight at the heart of embodiment research is that the particular, material human body is the nexus of two loci: as an integration of sensory apparatuses, the body is the receptive locus of the world; at the same time, the body is the locus of responsive engagement with the world. Working from the framework of embodiment, this essay is a theological exploration of the arts, with particular attention given to the artist. The first half details two controlling ideas about the nature of embodiment and the arts: (i) the arts are necessarily embodied, and (ii) the Christian artist is in Christ’s body. Here I examine how the artwork and the artist are necessarily embodied—the body is the horizon on which the arts are possible. With these two controlling ideas in hand, the second half of the essay considers three implications: (i) the artist works in and for the church; (ii) the arts are a gift of the Holy Spirit; and (iii) the arts are a place where the church experiences the Spirit’s working. These implications yield, among other insights, the finding that Christ’s body is the horizon on which the Christian arts are possible.
Journal Article
Bacterial Chemotaxis and the Question of Gain
Bray discusses clinical and experimental arguments over the question of the gain shown by swimming bacteria when they respond to chemical attractants. He examines the history of research into this area, the complications that surround it, and potential research avenues that may yield effective results.
Journal Article
Receptor clustering as a cellular mechanism to control sensitivity
Chemotactic bacteria such as
Escherichia coli
can detect and respond to extremely low concentrations of attractants, concentrations of less than 5 nM in the case of aspartate
1
. They also sense gradients of attractants extending over five orders of magnitude in concentration (up to 1 mM aspartate)
2
,
3
. Here we consider the possibility that this combination of sensitivity and range of response depends on the clustering of chemotactic receptors on the surface of the bacterium
4
. We examine what will happen if ligand binding changes the activity of a receptor, propagating this change in activity to neighbouring receptors in a cluster
5
,
6
. Calculations based on these assumptions show that sensitivity to extracellular ligands increases with the extent of spread of activity through an array of receptors, but that the range of concentrations over which the array works is severely diminished. However, a combination of low threshold of response and wide dynamic range can be attained if the cell has both clusters and single receptors on its surface, particularly if the extent of activity spread can adapt to external conditions. A mechanism of this kind can account quantitatively for the sensitivity and response range of
E. coli
to aspartate.
Journal Article
Molecular Networks: The Top-down View
Bray provides an overview of basic network properties that tells how a biological system works. Several types of molecular networks, including regular network, random network, and scale-free network, are discussed.
Journal Article
The Normative Orientations of Climate Scientists
In 1942 Robert K. Merton tried to demonstrate the structure of the normative system of science by specifying the norms that characterized it. The norms were assigned the abbreviation CUDOs: Communism, Universalism, Disinterestedness, and Organized skepticism. Using the results of an on-line survey of climate scientists concerning the norms of science, this paper explores the climate scientists’ subscription to these norms. The data suggests that while Merton’s CUDOs remain the overall guiding moral principles, they are not fully endorsed or present in the conduct of climate scientists: there is a tendency to withhold results until publication, there is the intention of maintaining property rights, there is external influence defining research and the tendency to assign the significance of authored work according to the status of the author rather than content of the paper. These are contrary to the norms of science as proposed by Robert K. Merton.
Journal Article
Computer-Based Analysis of the Binding Steps in Protein Complex Formation
Computer models were used to examine whether and under what conditions the multimeric protein complex is inhibited by high concentrations of one of its components--an effect analogous to the prozone phenomenon in precipitin tests. A series of idealized simple ``ball-and-stick'' structures representing small oligomeric complexes of protein molecules formed by reversible binding reactions were analyzed to determine the binding steps leading to each structure. The equilibrium state of each system was then determined over a range of starting concentrations and Kds and the steady-state concentration of structurally complete oligomer calculated for each situation. A strong inhibitory effect at high concentrations was shown by any protein molecule forming a bridge between two or more separable parts of the complex. By contrast, proteins linked to the outside of the complex by a single bond showed no inhibition whatsoever at any concentration. Nonbridging, multivalent proteins in the body of the complex could show an inhibitory effect or not depending on the structure of the complex and the strength of its bonds. On the basis of this study, we suggest that the prozone phenomenon will occur widely in living cells and that it could be a crucial factor in the regulation of protein complex formation.
Journal Article
Protein molecules as computational elements in living cells
Many proteins in living cells appear to have as their primary function the transfer and processing of information, rather than the chemical transformation of metabolic intermediates or the building of cellular structures. Such proteins are functionally linked through allosteric or other mechanisms into biochemical 'circuits' that perform a variety of simple computational tasks including amplification, integration and information storage.
Journal Article
B Cell Ligand Discrimination Through a Spreading and Contraction Response
B cells recognize foreign antigens by virtue of cell surface immunoglobulin receptors and are most effectively activated by membrane-bound ligands. Here, we show that in the early stages of this process, B cells exhibit a two-phase response in which they first spread over the antigen-bearing membrane and then contract, thereby collecting bound antigen into a central aggregate. The extent of this response, which is both signaling- and actin-dependent, determines the quantity of antigen accumulated and hence the degree of B cell activation. Brownian dynamic simulations reproduce essential features of the antigen collection process and suggest a possible basis for affinity discrimination. We propose that dynamic spreading is an important step of the immune response.
Journal Article