21,049 research outputs found
Some Tetranychoid Mites of Michigan
Excerpt: Tetranychoid mites are plant feeders, and many of them are of considerable economic importance. Prior to the present study, only seven species of these mites were known from Michigan; Oligonychus ilicis (McGregor) (McGregor, 1931); Tertranychus mcdanieli McGregor (McGregor, 1931; Pritchard and Baker, 1955); Euryteranychus buxi (Garman) (Ries, 1935; McGregor 1950); Tettranychus atlanticus McGregor (Tuttle and Baker, 1964); Bryobia praetiosa Koch, Panoychus ulmi (Koch), and Tetranychus telarius (L.) (Ghate and Howitt, 1965)
Landau theory of restart transitions
We develop a Landau like theory to characterize the phase transitions in
resetting systems. Restart can either accelerate or hinder the completion of a
first passage process. The transition between these two phases is characterized
by the behavioral change in the order parameter of the system namely the
optimal restart rate. Like in the original theory of Landau, the optimal
restart rate can undergo a first or second order transition depending on the
details of the system. Nonetheless, there exists no unified framework which can
capture the onset of such novel phenomena. We unravel this in a comprehensive
manner and show how the transition can be understood by analyzing the first
passage time moments. Power of our approach is demonstrated in two canonical
paradigm setup namely the Michaelis Menten chemical reaction and diffusion
under restart
A class of index coding problems with rate 1/3
An index coding problem with messages has symmetric rate if all
messages can be conveyed at rate . In a recent work, a class of index coding
problems for which symmetric rate is achievable was characterised
using special properties of the side-information available at the receivers. In
this paper, we show a larger class of index coding problems (which includes the
previous class of problems) for which symmetric rate is
achievable. In the process, we also obtain a stricter necessary condition for
rate feasibility than what is known in literature.Comment: Shorter version submitted to ISIT 201
Negative to Positive Magnetoresistance transition in Functionalization of Carbon nanotube and Polyaniline Composite
Electrical resistivity and magnetoresistance(MR) in polyaniline(PANI) with
carbon nanotube(CNT) and functionalized carbon nanotube(fCNT) composites have
been studied for different weight percentage down to the temperature 4.2K and
up to magnetic field 5T. Resistivity increases significantly in composite at
low temperature due to functionalization of CNT compare to only CNT.
Interestingly transition from negative to positive magnetoresistance has been
observed for 10wt% of composite as the effect of disorder is more in fCNT/PANI.
This result depicts that the MR has strong dependency on disorder in the
composite system. The transition of MR has been explained in the basis of
polaron-bipolaron model. The long range Coulomb interaction between two
polarons screened by disorder in the composite of fCNT/PANI, increases the
effective on-site Coulomb repulsion energy to form bipolaron which leads to
change the sign of MR from negative to positive.Comment: 5 pages, 8 figures; typos adde
Incomplete Information in a Long Run Risks Model of Asset Pricing
We study the effects of incorporating incomplete information in the recently developed long run risks model of asset pricing. Studying the effects of incomplete information in such a setting is tractable, especially in the homoskedastic case with no fluctuating economic uncertainty. The incomplete information model is solved using approximate analytical methods as in the complete information framework analyzed in the literature. Model implications on moments of endogenous variables of interest including rates of return are compared in the long run risks model with and without incomplete information.asset pricing; long run risks; incomplete information; Kalman filter; equity returns; riskfree returns
Driven inelastic Maxwell gases
We consider the inelastic Maxwell model, which consists of a collection of
particles that are characterized by only their velocities, and evolving through
binary collisions and external driving. At any instant, a particle is equally
likely to collide with any of the remaining particles. The system evolves in
continuous time with mutual collisions and driving taken to be point processes
with rates and respectively. The mutual collisions
conserve momentum and are inelastic, with a coefficient of restitution . The
velocity change of a particle with velocity , due to driving, is taken to be
, mimicking the collision with a vibrating wall,
where the coefficient of restitution of the particle with the "wall" and
is Gaussian white noise. The Ornstein-Uhlenbeck driving mechanism given
by is found to be a special case of the driving
modeled as a point process. Using both the continuum and discrete versions we
show that while the equations for the one-particle and the two-particle
velocity distribution functions do not close, the joint evolution equations of
the variance and the two-particle velocity correlation functions close. With
the exact formula for the variance we find that, for , the system
goes to a steady state. On the other hand, for , the system does not
have a steady state. Similarly, the system goes to a steady state for the
Ornstein-Uhlenbeck driving with , whereas for the purely
diffusive driving (), the system does not have a steady state.Comment: 9 pages, 4 figure
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