615 research outputs found
Integro-differential diffusion equation for continuous time random walk
In this paper we present an integro-differential diffusion equation for
continuous time random walk that is valid for a generic waiting time
probability density function. Using this equation we also study diffusion
behaviors for a couple of specific waiting time probability density functions
such as exponential, and a combination of power law and generalized
Mittag-Leffler function. We show that for the case of the exponential waiting
time probability density function a normal diffusion is generated and the
probability density function is Gaussian distribution. In the case of the
combination of a power-law and generalized Mittag-Leffler waiting probability
density function we obtain the subdiffusive behavior for all the time regions
from small to large times, and probability density function is non-Gaussian
distribution.Comment: 12 page
Relationship and Network Approach to Innovation and Capabilities Building in Small and Medium-Sized UK Organic Food and Drink Suppliers: A Literature Review
Both business and consumer markets of food and drink are increasingly changing, concomitant with changing consumer habits and lifestyles. Particularly in industrialised countries, there has been a tremendous growth in consumer interest for organic food in the last fifteen years, largely driven by the need for healthy food. These market changes have implications for the way firms in the food and
drink industry conduct their business. Nevertheless, unlike large firms, small suppliers tend to be constrained in terms of innovations and capabilities, for instance to enable them keep pace with market changes. Based on the literature review, this paper develops a framework that suggests that market-driven innovations may be developed and implemented through augmentation of small and
medium-sized suppliers’ (SMEs) own capabilities with those of their larger customers. This consequently would enable SMEs to keep pace with market changes and hence sustain their survival
Statistical Analysis of Small Ellerman Bomb Events
The properties of Ellerman bombs (EBs), small-scale brightenings in the
H-alpha line wings, have proved difficult to establish due to their size being
close to the spatial resolution of even the most advanced telescopes. Here, we
aim to infer the size and lifetime of EBs using high-resolution data of an
emerging active region collected using the Interferometric BIdimensional
Spectrometer (IBIS) and Rapid Oscillations of the Solar Atmosphere (ROSA)
instruments as well as the Helioseismic and Magnetic Imager (HMI) onboard the
Solar Dynamics Observatory (SDO). We develop an algorithm to track EBs through
their evolution, finding that EBs can often be much smaller (around 0.3") and
shorter lived (less than 1 minute) than previous estimates. A correlation
between G-band magnetic bright points and EBs is also found. Combining SDO/HMI
and G-band data gives a good proxy of the polarity for the vertical magnetic
field. It is found that EBs often occur both over regions of opposite polarity
flux and strong unipolar fields, possibly hinting at magnetic reconnection as a
driver of these events.The energetics of EB events is found to follow a
power-law distribution in the range of "nano-flare" (10^{22-25} ergs).Comment: 19 pages. 7 Figure
Static interactions and stability of matter in Rindler space
Dynamical issues associated with quantum fields in Rindler space are
addressed in a study of the interaction between two sources at rest generated
by the exchange of scalar particles, photons and gravitons. These static
interaction energies in Rindler space are shown to be scale invariant, complex
quantities. The imaginary part will be seen to have its quantum mechanical
origin in the presence of an infinity of zero modes in uniformly accelerated
frames which in turn are related to the radiation observed in inertial frames.
The impact of a uniform acceleration on the stability of matter and the
properties of particles is discussed and estimates are presented of the
instability of hydrogen atoms when approaching the horizon.Comment: 28 pages, 4 figure
Quasi-Moessbauer effect in two dimensions
Expressions for the absorption spectrum of a nucleus in a three- and a
two-dimensional crystal respectively are obtained analytically at zero and at
finite temperature respectively. It is found that for finite temperature in two
dimensions the Moessbauer effect vanishes but is replaced by what we call a
Quasi-Moessbauer effect. Possibilities to identify two-dimensional elastic
behavior are discussed.Comment: 18 pages, 5 figures, notation simplifie
Atom-atom correlations in colliding Bose-Einstein condensates
We analyze atom-atom correlations in the s-wave scattering halo of two colliding condensates. By developing a simple perturbative approach, we obtain explicit analytic results for the collinear (CL) and back-to-back (BB) correlations corresponding to realistic density profiles of the colliding condensates with interactions. The results in the short-time limit are in agreement with the first-principles simulations using the positive-P representation and provide analytic insights into the experimental observations of Perrin et al. [Phys. Rev. Lett. 99, 150405 (2007)]. For long collision durations, we predict that the BB correlation becomes broader than the CL correlatio
Spectra and Symmetry in Nuclear Pairing
We apply the algebraic Bethe ansatz technique to the nuclear pairing problem
with orbit dependent coupling constants and degenerate single particle energy
levels. We find the exact energies and eigenstates. We show that for a given
shell, there are degeneracies between the states corresponding to less and more
than half full shell. We also provide a technique to solve the equations of
Bethe ansatz.Comment: 15 pages of REVTEX with 2 eps figure
Critical properties and Bose Einstein Condensation in dimer spin systems
We analyze the spin relaxation time for a system made of weakly
coupled one dimensional ladders.This system allows to probe the dimensional
crossover between a Luttinger liquid and a Bose-Einstein condensateof magnons.
We obtain the temperature dependence of in the various dimensional
regimes, and discuss the experimental consequences.Comment: 4 pages, RevTeX 4, 3 EPS figure
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