623 research outputs found
Municipal Solid Waste Flow Control in the Post-Carbone World
Garbage will always ultimately be the government\u27s problem. Evolving environmental standards and state and federal policies will continue to require reasoned responses from local governments and municipal solid waste flow control is a vital cog in many jurisdictions\u27 solid waste management solutions. Without flow control of some form, governments\u27 ability to plan and provide for the most environmentally sound and economically acceptable solutions will wane, leaving the public vulnerable to the vagaries of a private market that does not have a duty to protect the public health and safety. The Carbone decision has blunted one of the local governments chief weapons-legislative flow control-and it appears Congress will not supply an adequate answer for many solid waste systems. More than ever, alternatives to legislative flow control will be needed to enable municipalities to fulfill their solid waste duties, to comply with federal and state mandates, and to provide workable, environmentally-sound, long-term solid waste programs serving the interests of the public health and safety. Local governments must act soon by examining these options and deciding which will best serve the public
Comparison of Four Different Embolic Materials For Uterine Artery Embolization In Post-Procedure MRI Enhancement
The aim of this study was to assess embolic agent equivalency in uterine artery embolization (UAE) using post-procedure MRI enhancement of uterine fibroids in patients embolized using Embosphere Microspheres, (EM) Contour SE spheres (CSE), Poly-Vinyl Alcohol particles (PVA) and Bead Block spheres (BB). A total of 84 women with 6-month MRI follow-up constituted this retrospective study. Within this group, 25 women were treated with PVA, 23 were treated with CSE, 19 were treated with EM and 17 were treated with BB. Pre- and post-procedure MRI exams were analyzed for the total number of fibroids present in the uterus of each patient and the percentage individual fibroid enhancement of each fibroid was scored in quartile intervals. The overall percentage change in enhancement was then calculated for each patient. Bivariate analysis using Generalized Linear Modeling and one-way ANOVA was used to assess differences in infarction by different embolic materials. Of patients treated with PVA and EM, there was a mean reduction in enhancement by 76.60% and 83.07%, respectively, compared to a mean reduction of 52.53% and 49.78% in patients treated with CSE and BB, respectively. There was a statistically significant difference between CSE or BB and EM or PVA. Patients treated with BB and CSE demonstrate a reduced degree of infarction on follow-up MRI than those patients treated with PVA or EM
Safeguarding Due Process in a Hostile Environment: Foreign Lawyers in South Africa
Part I of this note briefly describes the effect of apartheid on human rights in South Africa. It then examines how liberal South African attorneys use procedural due process, as defined by the rule of law, to counter these effects. Part II discusses the methods used by foreign attorneys to support South African human rights lawyers. In particular, this section focuses on the activities of the International Commission of Jurists and the Lawyers\u27 Committee for Civil Rights Under Law. The note concludes that infusing fair process into the South African legal order is the most significant contribution foreign lawyers can make to the protection of human rights within South Africa
Analytical Galaxy Profiles for Photometric and Lensing Analysis
This article introduces a family of analytical functions of the form x^{\nu}
K_{\nu}(x), where K_{\nu} is the incomplete Bessel function of the third kind.
This family of functions can describe the density profile, projected and
integrated light profiles and the gravitational potentials of galaxies. For the
proper choice of parameters, these functions accurately approximate Sersic
functions over a range of indices and are good fits to galaxy light profiles.
With an additional parameter corresponding to a galaxy core radius, these
functions can fit galaxy like M87 over a factor of 100,000 in radius. Unlike
Sersic profiles, these functions have simple analytical 2-dimensional and
3-dimensional Fourier transforms, so they are easily convolved with spatially
varying point spread function and are well suited for photometric and lensing
analysis. We use these functions to estimate the effects of seeing on lensing
measurements and show that high S/N measurements, even when the PSF is larger
than the galaxy effective radius, should be able to recover accurate estimates
of lensing distortions by weighting light in the outer isophotes that are less
effected by seeing
Denaturation of Circular DNA: Supercoil Mechanism
The denaturation transition which takes place in circular DNA is analyzed by
extending the Poland-Scheraga model to include the winding degrees of freedom.
We consider the case of a homopolymer whereby the winding number of the double
stranded helix, released by a loop denaturation, is absorbed by
\emph{supercoils}. We find that as in the case of linear DNA, the order of the
transition is determined by the loop exponent . However the first order
transition displayed by the PS model for in linear DNA is replaced by a
continuous transition with arbitrarily high order as approaches 2, while
the second-order transition found in the linear case in the regime
disappears. In addition, our analysis reveals that melting under fixed linking
number is a \emph{condensation transition}, where the condensate is a
macroscopic loop which appears above the critical temperature.Comment: 9 pages, 4 figure
Finite Mirror Effects in Advanced Interferometric Gravitational Wave Detectors
Thermal noise is expected to be the dominant source of noise in the most
sensitive frequency band of second generation ground based gravitational wave
detectors. Reshaping the beam to a flatter wider profile which probes more of
the mirror surface reduces this noise. The "Mesa" beam shape has been proposed
for this purpose and was subsequently generalized to a family of hyperboloidal
beams with two parameters: twist angle alpha and beam width D. Varying alpha
allows a continuous transition from the nearly-flat to the nearly-concentric
Mesa beam configurations. We analytically prove that in the limit of infinite D
hyperboloidal beams become Gaussians. The Advanced LIGO diffraction loss design
constraint is 1 ppm per bounce. In the past the diffraction loss has often been
calculated using the clipping approximation that, in general, underestimates
the diffraction loss. We develop a code using pseudo-spectral methods to
compute the diffraction loss directly from the propagator. We find that the
diffraction loss is not a strictly monotonic function of beam width, but has
local minima that occur due to finite mirror effects and leads to natural
choices of D. For the Mesa beam a local minimum occurs at D = 10.67 cm and
leads to a diffraction loss of 1.4 ppm. We find that if one requires a
diffraction loss of strictly 1 ppm, the alpha = 0.91 pi hyperboloidal beam is
optimal, leading to the coating thermal noise being lower by about 10% than for
a Mesa beam while other types of thermal noise decrease as well. We then
develop an iterative process that reconstructs the mirror to specifically
account for finite mirror effects. This allows us to increase the D parameter
and lower the coating noise by about 30% compared to the original Mesa
configuration.Comment: 13 pages, 12 figures, 4 tables. Referee input included and typos
fixed. Accepted by Phys. Rev.
Quarkonium states in a complex-valued potential
We calculate quarkonium binding energies using a realistic complex-valued
potential for both an isotropic and anisotropic quark-gluon plasma. We
determine the disassociation temperatures of the ground and first excited
states considering both the real and imaginary parts of the binding energy. We
show that the effect of momentum-space anisotropy is smaller on the imaginary
part of the binding energy than on the real part of the binding energy. In the
case that one assumes an isotropic plasma, we find disassociation temperatures
for the J/psi, Upsilon and chi_b of 1.6 T_c, 2.8 T_c, and 1.5 T_c,
respectively. We find that a finite oblate momentum-space anisotropy increases
the disassociation temperature for all states considered and results in a
splitting of the p-wave states associated with the chi_b first excited state of
bottomonium.Comment: 23 pages, 9 figures; v4: subtraction of V_infinity corrected to only
subtract Re[V_infinity
Approach to equilibrium of diffusion in a logarithmic potential
The late-time distribution function P(x,t) of a particle diffusing in a
one-dimensional logarithmic potential is calculated for arbitrary initial
conditions. We find a scaling solution with three surprising features: (i) the
solution is given by two distinct scaling forms, corresponding to a diffusive
(x ~ t^(1/2)) and a subdiffusive (x ~ t^{\gamma} with a given {\gamma} < 1/2)
length scale, respectively, (ii) the overall scaling function is selected by
the initial condition, and (iii) depending on the tail of the initial
condition, the scaling exponent which characterizes the scaling function is
found to exhibit a transition from a continuously varying to a fixed value.Comment: 4 pages, 3 figures; Published versio
Master-equation analysis of accelerating networks
In many real-world networks, the rates of node and link addition are time
dependent. This observation motivates the definition of accelerating networks.
There has been relatively little investigation of accelerating networks and
previous efforts at analyzing their degree distributions have employed
mean-field techniques. By contrast, we show that it is possible to apply a
master-equation approach to such network development. We provide full
time-dependent expressions for the evolution of the degree distributions for
the canonical situations of random and preferential attachment in networks
undergoing constant acceleration. These results are in excellent agreement with
results obtained from simulations. We note that a growing, non-equilibrium
network undergoing constant acceleration with random attachment is equivalent
to a classical random graph, bridging the gap between non-equilibrium and
classical equilibrium networks.Comment: 6 pages, 1 figure, 1 tabl
Spherical single-roll dynamos at large magnetic Reynolds numbers
This paper concerns kinematic helical dynamos in a spherical fluid body
surrounded by an insulator. In particular, we examine their behaviour in the
regime of large magnetic Reynolds number \Rm, for which dynamo action is
usually concentrated upon a simple resonant stream-surface. The dynamo
eigensolutions are computed numerically for two representative single-roll
flows using a compact spherical harmonic decomposition and fourth-order
finite-differences in radius. These solutions are then compared with the growth
rates and eigenfunctions of the Gilbert and Ponty (2000) large \Rm asymptotic
theory. We find good agreement between the growth rates when \Rm>10^4, and
between the eigenfunctions when \Rm>10^5.Comment: 36 pages, 8 figures. V2: incorrect labels in Fig3 corrected. The
article appears in Physics of Fluids, 22, 066601, and may be found at
http://pof.aip.org/phfle6/v22/i6/p066601_s1 . (Copyright 2010 American
Institute of Physics. This article may be downloaded for personal use only.
Any other use requires prior permission of the author and the American
Institute of Physics
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