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A review of the Yorkshire and Humber regional waste strategy
Managing waste has become a primary issue for regional planners. This article reports on the institutional process underpinning the region’s strategy and the stages in its production. It emphasises that there has been a watering down of the target for household waste production without appropriate explanation
Quantum tunneling of the Neel vector in antiferromagnetic [3 x 3] grid molecules
Based on numerical calculations it is shown that the antiferromagnetic grid
molecule Mn-[3 x 3] is a very promising candidate to experimentally detect the
phenomenon of quantum tunneling of the Neel vector.Comment: 4 pages, 3 figures, REVTEX 4, to appear in PR
Condensation Transition in Polydisperse Hard Rods
We study a mass transport model, where spherical particles diffusing on a
ring can stochastically exchange volume , with the constraint of a fixed
total volume , being the total number of particles. The
particles, referred to as -spheres, have a linear size that behaves as
and our model thus represents a gas of polydisperse hard rods with
variable diameters . We show that our model admits a factorized
steady state distribution which provides the size distribution that minimizes
the free energy of a polydisperse hard rod system, under the constraints of
fixed and . Complementary approaches (explicit construction of the
steady state distribution on the one hand ; density functional theory on the
other hand) completely and consistently specify the behaviour of the system. A
real space condensation transition is shown to take place for : beyond a
critical density a macroscopic aggregate is formed and coexists with a critical
fluid phase. Our work establishes the bridge between stochastic mass transport
approaches and the optimal polydispersity of hard sphere fluids studied in
previous articles
Comptonisation of Cosmic Microwave Background Photons in Dwarf Spheroidal Galaxies
We present theoretical modelling of the electron distribution produced by
annihilating neutralino dark matter in dwarf spheroidal galaxies (dSphs). In
particular, we follow up the idea of Colafrancesco (2004) and find that such
electrons distort the cosmic microwave background (CMB) by the
Sunyaev-Zeldovich effect. For an assumed neutralino mass of 10 GeV and beam
size of 1'', the SZ temperature decrement is of the order of nano-Kelvin for
dSph models with a soft core. By contrast, it is of the order of micro-Kelvin
for the strongly cusped dSph models favoured by some cosmological simulations.
Although this is out of reach of current instruments, it may well be detectable
by future mm telescopes, such as ALMA. We also show that the upscattered CMB
photons have energies within reach of upcoming X-ray observatories, but that
the flux of such photons is too small to be detectable soon. Nonetheless, we
conclude that searching for the dark matter induced Sunyaev-Zeldovich effect is
a promising way of constraining the dark distribution in dSphs, especially if
the particles are light.Comment: 10 pages, 5 figures, MNRAS, in pres
Interaction driven real-space condensation
We study real-space condensation in a broad class of stochastic mass
transport models. We show that the steady state of such models has a
pair-factorised form which generalizes the standard factorized steady states.
The condensation in this class of models is driven by interactions which give
rise to a spatially extended condensate that differs fundamentally from the
previously studied examples. We present numerical results as well as a
theoretical analysis of the condensation transition and show that the criterion
for condensation is related to the binding-unbinding transition of
solid-on-solid interfaces.Comment: 4 page
Construction of the factorized steady state distribution in models of mass transport
For a class of one-dimensional mass transport models we present a simple and
direct test on the chipping functions, which define the probabilities for mass
to be transferred to neighbouring sites, to determine whether the stationary
distribution is factorized. In cases where the answer is affirmative, we
provide an explicit method for constructing the single-site weight function. As
an illustration of the power of this approach, previously known results on the
Zero-range process and Asymmetric random average process are recovered in a few
lines. We also construct new models, namely a generalized Zero-range process
and a binomial chipping model, which have factorized steady states.Comment: 6 pages, no figure
Condensation transitions in a model for a directed network with weighted links
An exactly solvable model for the rewiring dynamics of weighted, directed
networks is introduced. Simulations indicate that the model exhibits two types
of condensation: (i) a phase in which, for each node, a finite fraction of its
total out-strength condenses onto a single link; (ii) a phase in which a finite
fraction of the total weight in the system is directed into a single node. A
virtue of the model is that its dynamics can be mapped onto those of a
zero-range process with many species of interacting particles -- an exactly
solvable model of particles hopping between the sites of a lattice. This
mapping, which is described in detail, guides the analysis of the steady state
of the network model and leads to theoretical predictions for the conditions
under which the different types of condensation may be observed. A further
advantage of the mapping is that, by exploiting what is known about exactly
solvable generalisations of the zero-range process, one can infer a number of
generalisations of the network model and dynamics which remain exactly
solvable.Comment: 23 pages, 8 figure
NICMOS Observations of Interaction Triggered Star Formation in the Luminous Infrared Galaxy NGC 6090
High resolution, 1.1, 1.6, and 2.2 micron imaging of the luminous infrared
galaxy NGC 6090 obtained with NICMOS of the Hubble Space Telescope are
presented. These new observations are centered on the two nuclei of the merger,
and reveal the spiral structure of the eastern galaxy and the amorphous nature
of the western galaxy. The nuclear separation of 3.2 kpc (H_0 = 75 km/s/Mpc)
indicates that NGC 6090 is at an intermediate stage of merging. Bright
knots/clusters are also visible in the region overlapping the merging galaxies;
four of these knots appear bluer than the underlying galaxies and have colors
consistent with young (<~ 10^7 yr) star clusters. The spatial coincidence of
the knots with the molecular gas in NGC 6090 indicates that much of the present
star formation is occuring outside of the nuclear region of merging galaxies,
consistent with recent studies of other double nuclei luminous infrared
galaxies.Comment: LaTex, 18 pages with 4 jpg figures, ApJ, in pres
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