33 research outputs found
Anomalous diffusion and anisotropic nonlinear Fokker-Planck equation
We analyse a bidimensional nonlinear Fokker-Planck equation by considering an
anisotropic case, whose diffusion coefficients are
and with . In this
context, we also investigate two situations with the drift force
. The first one is characterized by
and the second is given by and
. In these cases, we can verify an anomalous behavior induced in
different directions by the drift force applied. The found results are exact
and exhibit, in terms of the -exponentials, functions which emerge from the
Tsallis formalism. The generalization for the -dimensional case is
discussed.Comment: 6 pages, tex fil
Remarks on expansion and factorization approximation in the Tsallis nonextensive statistical mechanics
The validity of (1-q) expansion and factorization approximations are analysed
in the framework of Tsallis statistics. We employ exact expressions for
classical independent systems (harmonic oscillators) by considering the
unnormalized and normalized constrainsts. We show that these approxiamtions can
not be accurate in the analysis of systems with many degrees of freedom.Comment: Latex, 6 pages, 2 figure
Path Integral Approach to the Nonextensive Canonical Density Matrix
Feynman's path integral is herein generalized to the nonextensive canonical
density matrix based on Tsallis entropy. This generalization is done in two
ways by using unnormalized and normalized constraints. Firstly, we consider the
path integral formulation with unnormalized constraints, and this
generalization is worked out through two different ways, which are shown to be
equivalent. These formulations with unnormalized constraints are solutions to
two generalized Bloch equations proposed in this work. The first form of the
generalized Bloch equation is linear, but with a temperature-dependent
effective Hamiltonian; the second form is nonlinear and resembles the anomalous
correlated diffusion equation (porous medium equation). Furthermore, we can
extend these results to the prescription of field theory using integral
representations. The second development is dedicated to analyzing the path
integral formulation with normalized constraints.
To illustrate the methods introduced here, we analyze the free particle case
and a non-interacting scalar field. The results herein obtained are expected to
be useful in the discussion of generic nonextensive contexts.Comment: (Univ. Est. de Maringa, PR- Brazil),17 pages, Late
Anomalous diffusion, nonlinear fractional Fokker-Planck equation and solutions
We obtain new exact classes of solutions for the nonlinear fractional
Fokker-Planck-like equation partial_t rho = partial_x{D(x) partial^{mu -1}_x
rho^{nu} - F(x) rho} by considering a diffusion coefficient D = D|x|^{-theta}
(theta in R and D>0) and a drift force F = -k_1 x + k-bar_{gamma}
x|x|^{gamma-1} (k_1, k-bar_{gamma}, gamma in R). Connection with nonextensive
statistical mechanics based on Tsallis entropy is also discussed.Comment: latex, 5 pages. Submitted to Physica
Nonextensive Statistical Mechanics Application to Vibrational Dynamics of Protein Folding
The vibrational dynamics of protein folding is analyzed in the framework of
Tsallis thermostatistics. The generalized partition functions, internal
energies, free energies and temperature factor (or Debye-Waller factor) are
calculated. It has also been observed that the temperature factor is dependent
on the non-extensive parameter q which behaves like a scale parameter in the
harmonic oscillator model. As , we also show that these approximations
agree with the result of Gaussian network model.Comment: 8 pages, 2 figure
Isospin symmetry in the odd-odd mirror nuclei 44V/44Sc
Excited states in the N=Z-2 nucleus 44V have been observed for the first time. The states have been identified through particle-γ-γ coincidence relationships and comparison with analog states in the mirror nucleus 44Sc. Mirror energy differences have been extracted and compared to state-of-the-art shell-model calculations which include charge-symmetry-breaking forces. Observed decay pattern asymmetries between the mirror pair are discussed in terms of core excitations, electromagnetic spin-orbit effects and isospin mixing
A critique of non-extensive q-entropy for thermal statistics
During the past dozen years there have been numerous articles on a relation
between entropy and probability which is non-additive and has a parameter
that depends on the nature of the thermodynamic system under consideration. For
this relation corresponds to the Boltzmann-Gibbs entropy, but for other
values of it is claimed that it leads to a formalism which is consistent
with the laws of thermodynamics. However, it is shown here that the joint
entropy for systems having {\it different} values of is not defined in this
formalism, and consequently fundamental thermodynamic concepts such as
temperature and heat exchange cannot be considered for such systems. Moreover,
for the probability distribution for weakly interacting systems does
not factor into the product of the probability distribution for the separate
systems, leading to spurious correlations and other unphysical consequences,
e.g. non-extensive energy, that have been ignored in various applications given
in the literature
Thermodynamic Derivation of the Tsallis and R\'enyi Entropy Formulas and the Temperature of Quark-Gluon Plasma
We derive Tsallis entropy, Sq, from universal thermostat independence and
obtain the functional form of the corresponding generalized entropy-probability
relation. Our result for finite thermostats interprets thermodynamically the
subsystem temperature, T1, and the index q in terms of the temperature, T,
entropy, S, and heat capacity, C of the reservoir as T1 = T exp(-S/C) and q = 1
- 1/C. In the infinite C limit, irrespective to the value of S, the
Boltzmann-Gibbs approach is fully recovered. We apply this framework for the
experimental determination of the original temperature of a finite thermostat,
T, from the analysis of hadron spectra produced in high energy collisions, by
analyzing frequently considered simple models of the quark-gluon plasma.Comment: 4 pages 1 Figure PRL style, revised presentatio
Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries
Background
Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.
Methods
This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries.
Results
In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.
Conclusion
This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries