16,318 research outputs found
Canonical partition function for anomalous systems described by the -entropy
Starting from the -distribution function, obtained by applying the
maximal entropy principle to the -entropy [G. Kaniadakis, Phys. Rev. E
66 (2002), 056125], we derive the expression of the canonical
-partition function and discuss its main properties. It is shown that
all important macroscopical quantities of the system can be expressed employing
only the -partition function. The relationship between the associated
-free energy and the -entropy is also discussed.Comment: 8 pages, no figures. Work presented at the International conference
Complexity and Nonextensivity: New Trends in Statistical Mechanics. - Yukawa
Institute for Theoretical Physics - (14-18 March 2005) Kyoto, Japa
Sequencing Renewables: Groundwater, Recycled Water, and Desalination
Optimal recycling of minerals can be thought of as an integral part of the theory of the mine. In this paper, we consider the role that wastewater recycling plays in the optimal extraction of groundwater, a renewable resource. We develop a two-sector dynamic optimization model to solve for the optimal trajectories of groundwater extraction and water recycling. For the case of spatially increasing recycling costs, recycled water serves as a supplemental resource in transition to the steady state. For constant unit recycling cost, recycled wastewater is eventually used as a sector-specific backstop for agricultural users, while desalination supplements household groundwater in the steady state. In both cases, recycling water increases welfare by shifting demand away from the aquifer, thus delaying implementation of costly desalination. The model provides guidance on when and how much to develop resource alternatives.Renewable resources, dynamic optimization, groundwater allocation, wastewater reuse, recycling, reclamation, water quality, Environmental Economics and Policy, Resource /Energy Economics and Policy, Q25, Q28, C6,
Partly melted DNA conformations obtained with a probability peak finding method
Peaks in the probabilities of loops or bubbles, helical segments, and
unzipping ends in melting DNA are found in this article using a peak finding
method that maps the hierarchical structure of certain energy landscapes. The
peaks indicate the alternative conformations that coexist in equilibrium and
the range of their fluctuations. This yields a representation of the
conformational ensemble at a given temperature, which is illustrated in a
single diagram called a stitch profile. This article describes the methodology
and discusses stitch profiles vs. the ordinary probability profiles using the
phage lambda genome as an example.Comment: 11 pages, 9 figures; v3: major changes; v4: applications sectio
Composition law of -entropy for statistically independent systems
The intriguing and still open question concerning the composition law of
-entropy with and is here
reconsidered and solved. It is shown that, for a statistical system described
by the probability distribution , made up of two statistically
independent subsystems, described through the probability distributions and , respectively, with , the joint entropy
can be obtained starting from the and
entropies, and additionally from the entropic functionals
and , being
the -Napier number. The composition law of the -entropy is
given in closed form, and emerges as a one-parameter generalization of the
ordinary additivity law of Boltzmann-Shannon entropy recovered in the limit.Comment: 14 page
Non-equilibrium hydrodynamics of a rotating filament
The nonlinear dynamics of an elastic filament that is forced to rotate at its
base is studied by hydrodynamic simulation techniques; coupling between
stretch, bend, twist elasticity and thermal fluctuations is included. The
twirling-overwhirling transition is located and found to be strongly
discontinuous. For finite bend and twist persistence length, thermal
fluctuations lower the threshold rotational frequency, for infinite persistence
length the threshold agrees with previous analytical predictions
Density PDFs of diffuse gas in the Milky Way
The probability distribution functions (PDFs) of the average densities of the
diffuse ionized gas (DIG) and the diffuse atomic gas are close to lognormal,
especially when lines of sight at |b|5 degree are considered
separately. Our results provide strong support for the existence of a lognormal
density PDF in the diffuse ISM, consistent with a turbulent origin of density
structure in the diffuse gas.Comment: 4 pages, 1 figure. To be published in the proceedings of the August
2008 conference (held in Eapinho, Portugal) "The Role of Disk-Halo
Interaction in Galaxy Evolution: Outflow vs Infall?", Ed. M. A. de Avillez,
EAS Publications Serie
Obscuring Material around Seyfert Nuclei with Starbursts
The structure of obscuring matter in the environment of active galactic
nuclei with associated nuclear starbursts is investigated using 3-D
hydrodynamical simulations. Simple analytical estimates suggest that the
obscuring matter with energy feedback from supernovae has a torus-like
structure with a radius of several tens of parsecs and a scale height of about
10 pc. These estimates are confirmed by the fully non-linear numerical
simulations, in which the multi-phase inhomogeneous interstellar matter and its
interaction with the supernovae are consistently followed. The globally stable,
torus-like structure is highly inhomogeneous and turbulent. To achieve the high
column densities (> 10^{24} cm^{-2}) as suggested by observations of some
Seyfert 2 galaxies with nuclear starbursts, the viewing angle should be larger
than about 70 degree from the pole-on for a 10^8 solar mass massive black hole.
Due to the inhomogeneous internal structure of the torus, the observed column
density is sensitive to the line-of-sight, and it fluctuates by a factor of
order 100. The covering fraction for N > 10^{23} cm^{-2} is about 0.4. The
average accretion rate toward R < 1 pc is 0.4 solar mass/yr, which is boosted
to twice that in the model without the energy feedback.Comment: ApJL in press (4 pages, 3 figures) A gziped ps file with high
resolution figures is available at http://th.nao.ac.jp/~wada/AGN
A non self-referential expression of Tsallis' probability distribution function
The canonical probability distribution function (pdf) obtained by optimizing
the Tsallis entropy under the linear mean energy constraint (first formalism)
or the escort mean energy constraint (third formalism) suffer
self-referentiality. In a recent paper [Phys. Lett. A {\bf335} (2005) 351-362]
the authors have shown that the pdfs obtained in the two formalisms are
equivalent to the pdf in non self-referential form. Based on this result we
derive an alternative expression, which is non self-referential, for the
Tsallis distributions in both first and third formalisms.Comment: 3 page
Discrete elastic model for stretching-induced flagellar polymorphs
Force-induced reversible transformations between coiled and normal polymorphs
of bacterial flagella have been observed in recent optical-tweezer experiment.
We introduce a discrete elastic rod model with two competing helical states
governed by a fluctuating spin-like variable that represents the underlying
conformational states of flagellin monomers. Using hybrid Brownian dynamics
Monte-Carlo simulations, we show that a helix undergoes shape transitions
dominated by domain wall nucleation and motion in response to externally
applied uniaxial tension. A scaling argument for the critical force is
presented in good agreement with experimental and simulation results.
Stretching rate-dependent elasticity including a buckling instability are
found, also consistent with the experiment
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