Deleuzian dragons: Thinking Chinese strategic spatial planning with Gilles Deleuze

As symbols of adaptability and transformation, together with qualities of vigilance and intelligence, we argue the relevance of dragons for spatial planning in China. We develop a metaphorical concept - the green dragon - for grasping the condition of contemporary Chinese societies and for facilitating the development of theories and practices of spatial planning which are able to face the challenges of rapid change. We ask Chinese scholars and spatial planners to liberate Deleuzian potential for strategic spatial planning in a 'becoming-between, coming-together' of concepts which can effectively make a difference in the world. Having outlined what we regard as key transversals or diagonals between our reading of Gilles Deleuze and aspects of Chinese philosophy, we then offer the metaphor of strategic spatial planning as Chinese literati landscape painting. This is a form of painting which rejects the idea of the world being supremely organised from a particular point of view, preferring to paint immanence and transformation. Chinese literati landscape paintings, like philosophy and strategic spatial planning, 'look only at the movements'. We conclude that connections between what concepts of Chinese philosophy and those of Gilles Deleuze can do, suggest that in China, a conception of strategic spatial planning as metaphorical green dragon may offer academics and planning practitioners a transverse way to relate the legacies of past philosophies and curren

The UV Scattering Halo of the Central Source Associated with Eta Carinae

We have made an extensive study of the UV spectrum of Eta Carinae, and find that we do not directly observe the star and its wind in the UV. Because of dust along our line of sight, the UV light that we observe arises from bound-bound scattering at large impact parameters. We obtain a reasonable fit to the UV spectrum by using only the flux that originates outside 0.033". This explains why we can still observe the primary star in the UV despite the large optical extinction -- it is due to the presence of an intrinsic coronagraph in the Eta Carinae system, and to the extension of the UV emitting region. It is not due to peculiar dust properties alone. We have computed the spectrum of the purported companion star, and show that it could only be directly detected in the UV spectrum preferentially in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectral region (912-1175 Ang.). However, we find no direct evidence for a companion star, with the properties indicated by X-ray studies and studies of the Weigelt blobs, in UV spectra. This might be due to reprocessing of the companion's light by the dense stellar wind of the primary. Broad FeII and [FeII] emission lines, which form in the stellar wind, are detected in spectra taken in the SE lobe, 0.2" from the central star. The wind spectrum shows some similarities to the spectra of the B & D Weigelt blobs, but also shows some marked differences in that high excitation lines, and lines pumped by Ly-alpha, are not seen. The detection of the broad lines lends support to our interpretation of the UV spectrum, and to our model for Eta Carinae.Comment: To appear in ApJ. 57 pages with 18 figure

On the He II Emission In Eta Carinae and the Origin of Its Spectroscopic Events

We describe and analyze Hubble Space Telescope (HST) observations of transient emission near 4680 {\AA} in Eta Car, reported earlier by Steiner & Damineli (2004). If, as seems probable, this is He II $\lambda$4687, then it is a unique clue to Eta Car's 5.5-year cycle. According to our analysis, several aspects of this feature support a mass-ejection model of the observed spectroscopic events, and not an eclipse model. The He II emission appeared in early 2003, grew to a brief maximum during the 2003.5 spectroscopic event, and then abruptly disappeared. It did not appear in any other HST spectra before or after the event. The peak brightness was larger than previously reported, and is difficult to explain even if one allows for an uncertainty factor of order 3. The stellar wind must provide a temporary larger-than-normal energy supply, and we describe a special form of radiative amplification that may also be needed. These characteristics are consistent with a class of mass-ejection or wind-disturbance scenarios, which have implications for the physical structure and stability of Eta Car.Comment: 47 pages (including all appendices, tabs, & figs), 9 figures, 3 tables; submitted to Astrophysical Journal (2005 March 29), accepted for publication in Ap

Neutron scattering study of magnetic ordering and excitations in the ternary rare-earth diborocarbide Ce^{11}B_2C_2

Neutron scattering experiments have been performed on the ternary rare-earth diborocarbide Ce$^{11}$B$_2$C$_2$. The powder diffraction experiment confirms formation of a long-range magnetic order at $T_{\rm N} = 7.3$ K, where a sinusoidally modulated structure is realized with the modulation vector ${\bm q} = [0.167(3), 0.167(3), 0.114(3)]$. Inelastic excitation spectra in the paramagnetic phase comprise significantly broad quasielastic and inelastic peaks centered at $\hbar \omega \approx 0, 8$ and 65 meV. Crystalline-electric-field (CEF) analysis satisfactorily reproduces the observed spectra, confirming their CEF origin. The broadness of the quasielastic peak indicates strong spin fluctuations due to coupling between localized $4f$ spins and conduction electrons in the paramagnetic phase. A prominent feature is suppression of the quasielastic fluctuations, and concomitant growth of a sharp inelastic peak in a low energy region below $T_{\rm N}$. This suggests dissociation of the conduction and localized $4f$ electrons on ordering, and contrasts the presently observed incommensurate phase with spin-density-wave order frequently seen in heavy fermion compounds, such as Ce(Ru$_{1-x}$La$_x$)$_2$Si$_2$.Comment: accepted for publication in Phys. Rev.

A multispectral view of the periodic events in eta Carinae

A full description of the 5.5-yr low excitation events in Eta Carinae is presented. We show that they are not as simple and brief as previously thought, but a combination of two components. The first, the 'slow variation' component, is revealed by slow changes in the ionization level of circumstellar matter across the whole cycle and is caused by gradual changes in the wind-wind collision shock-cone orientation, angular opening and gaseous content. The second, the 'collapse' component, is restricted to around the minimum, and is due to a temporary global collapse of the wind-wind collision shock. High energy photons (E > 16 eV) from the companion star are strongly shielded, leaving the Weigelt objects at low ionization state for >6 months. High energy phenomena are sensitive only to the 'collapse', low energy only to the 'slow variation' and intermediate energies to both components. Simple eclipses and mechanisms effective only near periastron (e.g., shell ejection or accretion onto the secondary star) cannot account for the whole 5.5-yr cycle. We find anti-correlated changes in the intensity and the radial velocity of P Cygni absorption profiles in FeII 6455 and HeI 7065 lines, indicating that the former is associated to the primary and the latter to the secondary star. We present a set of light curves representative of the whole spectrum, useful for monitoring the next event (2009 January 11).Comment: 16 pages, 7 EPS figures, accepted for publication on MNRA

Characterisation of spatial network-like patterns from junctions' geometry

We propose a new method for quantitative characterization of spatial network-like patterns with loops, such as surface fracture patterns, leaf vein networks and patterns of urban streets. Such patterns are not well characterized by purely topological estimators: also patterns that both look different and result from different morphogenetic processes can have similar topology. A local geometric cue -the angles formed by the different branches at junctions- can complement topological information and allow to quantify the large scale spatial coherence of the pattern. For patterns that grow over time, such as fracture lines on the surface of ceramics, the rank assigned by our method to each individual segment of the pattern approximates the order of appearance of that segment. We apply the method to various network-like patterns and we find a continuous but sharp dichotomy between two classes of spatial networks: hierarchical and homogeneous. The first class results from a sequential growth process and presents large scale organization, the latter presents local, but not global organization.Comment: version 2, 14 page