5,944 research outputs found
Delivering Urban Wellbeing through Transformative Community Enterprise
(c) The Author/sChristchurch, New Zealan
Fluctuating loops and glassy dynamics of a pinned line in two dimensions
We represent the slow, glassy equilibrium dynamics of a line in a
two-dimensional random potential landscape as driven by an array of
asymptotically independent two-state systems, or loops, fluctuating on all
length scales. The assumption of independence enables a fairly complete
analytic description. We obtain good agreement with Monte Carlo simulations
when the free energy barriers separating the two sides of a loop of size L are
drawn from a distribution whose width and mean scale as L^(1/3), in agreement
with recent results for scaling of such barriers.Comment: 11 pages, 4 Postscript figure
Energy Barriers for Flux Lines in 3 Dimensions
I determine the scaling behavior of the free energy barriers encountered by a
flux line in moving through a three-dimensional random potential. A combination
of numerical simulations and analytic arguments suggest that these barriers
scale with the length of the line in the same way as the fluctuation in the
free energy.Comment: 12 pages Latex, 4 postscript figures tarred, compressed, uuencoded
using `uufiles', coming with a separate fil
Coupled non-equilibrium growth equations: Self-consistent mode coupling using vertex renormalization
We find that studying the simplest of the coupled non-equilibrium growth
equations of Barabasi by self-consistent mode coupling requires the use of
dressed vertices. Using the vertex renormalization, we find a roughness
exponent which already in the leading order is quite close to the numerical
value.Comment: 7 pages, 3 figure
Single particle characterization using the soot particle aerosol mass spectrometer (SP-AMS)
Understanding the impact of atmospheric black carbon (BC) containing particles on human health and radiative forcing requires knowledge of the mixing state of BC, including the characteristics of the materials with which it is internally mixed. In this study, we demonstrate for the first time the capabilities of the Aerodyne Soot-Particle Aerosol Mass Spectrometer equipped with a light scattering module (LS-SP-AMS) to examine the mixing state of refractory BC (rBC) and other aerosol components in an urban environment (downtown Toronto). K-means clustering analysis was used to classify single particle mass spectra into chemically distinct groups. One resultant cluster is dominated by rBC mass spectral signals (C+1 to C+5) while the organic signals fall into a few major clusters, identified as hydrocarbon-like organic aerosol (HOA), oxygenated organic aerosol (OOA), and cooking emission organic aerosol (COA). A nearly external mixing is observed with small BC particles only thinly coated by HOA ( 28% by mass on average), while over 90% of the HOA-rich particles did not contain detectable amounts of rBC. Most of the particles classified into other inorganic and organic clusters were not significantly associated with BC. The single particle results also suggest that HOA and COA emitted from anthropogenic sources were likely major contributors to organic-rich particles with low to mid-range aerodynamic diameter (dva). The similar temporal profiles and mass spectral features of the organic clusters and the factors from a positive matrix factorization (PMF) analysis of the ensemble aerosol dataset validate the conventional interpretation of the PMF results
Upper critical dimension, dynamic exponent and scaling functions in the mode-coupling theory for the Kardar-Parisi-Zhang equation
We study the mode-coupling approximation for the KPZ equation in the strong
coupling regime. By constructing an ansatz consistent with the asymptotic forms
of the correlation and response functions we determine the upper critical
dimension d_c=4, and the expansion z=2-(d-4)/4+O((4-d)^2) around d_c. We find
the exact z=3/2 value in d=1, and estimate the values 1.62, 1.78 for z, in
d=2,3. The result d_c=4 and the expansion around d_c are very robust and can be
derived just from a mild assumption on the relative scale on which the response
and correlation functions vary as z approaches 2.Comment: RevTex, 4 page
On Critical Exponents and the Renormalization of the Coupling Constant in Growth Models with Surface Diffusion
It is shown by the method of renormalized field theory that in contrast to a
statement based on a mathematically ill-defined invariance transformation and
found in most of the recent publications on growth models with surface
diffusion, the coupling constant of these models renormalizes nontrivially.
This implies that the widely accepted supposedly exact scaling exponents are to
be corrected. A two-loop calculation shows that the corrections are small and
these exponents seem to be very good approximations.Comment: 4 pages, revtex, 2 postscript figures, to appear in Phys.Rev.Let
Quenched Averages for self-avoiding walks and polygons on deterministic fractals
We study rooted self avoiding polygons and self avoiding walks on
deterministic fractal lattices of finite ramification index. Different sites on
such lattices are not equivalent, and the number of rooted open walks W_n(S),
and rooted self-avoiding polygons P_n(S) of n steps depend on the root S. We
use exact recursion equations on the fractal to determine the generating
functions for P_n(S), and W_n(S) for an arbitrary point S on the lattice. These
are used to compute the averages and over different positions of S. We find that the connectivity constant
, and the radius of gyration exponent are the same for the annealed
and quenched averages. However, , and , where the exponents
and take values different from the annealed case. These
are expressed as the Lyapunov exponents of random product of finite-dimensional
matrices. For the 3-simplex lattice, our numerical estimation gives ; and , to be
compared with the annealed values and .Comment: 17 pages, 10 figures, submitted to Journal of Statistical Physic
Parents’ participation in child protection practice: toward respect and inclusion
In this article, we focus on parents' opportunities for, and experiences of, participation in child protection decision making in Queensland, Australia. Drawing on a qualitative analysis of 10 interviews with parents who have children 0-8 years of age and who have been subject to child protection investigation, we examine parents' perceptions of the process. Parents reported a range of difficulties in interactions with practitioners, Including family-related and systemic factors; the most common grievances Involved poor communication practices and negative worker attitudes, which created further disengagement. Conversely, interactions involving a willingness to listen, support, and provide for goal-focused plans were seen as faCilitating positive outcomes. Taking into account the case complexity and Interrelationships between workers' and clients' atfltudes and behaViours, we discuss strategies for promoflng parents' participation
Soluble Infinite-Range Model of Kinetic Roughening
A modified Kardar-Parisi-Zhang (KPZ) equation is introduced, and solved
exactly in the infinite-range limit. In the low-noise limit the system exhibits
a weak-to-strong coupling transition, rounded for non-zero noise, as a function
of the KPZ non-linearity. The strong-coupling regime is characterised by a
double-peaked height distribution in the stationary state. The nonstationary
dynamics is quite different from that of the stationary state.Comment: 13 pages, revtex, 1 postscript figur
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