4,775 research outputs found
A Study of the Implications of Vandalism with Relationship to Budgeting Costs for Secondary School Buildings in 89 Class III School Districts in 33 Counties, Eastern Nebraska.
Defense is first in this nation. The highest single cost paid out by the government of the United States is for defense of this country and its many holdings and interests in the world. Therefore, it would appear the people of the world are a violent people. Wars have been fought, nations and principalities have been defeated, and a great many lives have been lost in defense of cherished belongings
Bidirectional transport on a dynamic lattice
Bidirectional variants of stochastic many particle models for transport by
molecular motors show a strong tendency to form macroscopic clusters on static
lattices. Inspired by the fact that the microscopic tracks for molecular motors
are dynamical, we study the influence of different types of lattice dynamics on
stochastic bidirectional transport. We observe a transition toward efficient
transport (corresponding to the dissolution of large clusters) controlled by
the lattice dynamics.Comment: 5 pages, 5 figure
Effects of burying and removing dead leaves from the ground on the development of scab epidemics in an apple organic orchard.
Ascospores produced on scabbed leaves in the leaf litter constitute the primary
inoculum causing scab infections in apple orchards during the year. The trial, carried
out in a commercial organic orchard, permitted to evaluate the effects of the
removal of dead leaves located on the inter-row supplemented by the ploughing in of
the leaves left on the row, on the development of scab epidemics. From the first
recorded contamination to harvest time, lesions on leaves and fruits were counted to
determine reduction in disease incidence and severity, compared with the untreated
plots. Disease severity as a function of the distance from the untreated plot was also
observed, to evaluate the spore dispersal gradient within the orchard. The results
show that the ploughing in and the removal of the litter reduced disease incidence by
62% on leaves, and by almost 82% on fruits to harvest. Moreover, measurements of
the dispersal gradient show that the spores do not disperse, or little, beyond 20m of
the untreated zone
Particle interactions and lattice dynamics: Scenarios for efficient bidirectional stochastic transport?
Intracellular transport processes driven by molecular motors can be described
by stochastic lattice models of self-driven particles. Here we focus on
bidirectional transport models excluding the exchange of particles on the same
track. We explore the possibility to have efficient transport in these systems.
One possibility would be to have appropriate interactions between the various
motors' species, so as to form lanes. However, we show that the lane formation
mechanism based on modified attachment/detachment rates as it was proposed
previously is not necessarily connected to an efficient transport state and is
suppressed when the diffusivity of unbound particles is finite. We propose
another interaction mechanism based on obstacle avoidance that allows to have
lane formation for limited diffusion. Besides, we had shown in a separate paper
that the dynamics of the lattice itself could be a key ingredient for the
efficiency of bidirectional transport. Here we show that lattice dynamics and
interactions can both contribute in a cooperative way to the efficiency of
transport. In particular, lattice dynamics can decrease the interaction
threshold beyond which lanes form. Lattice dynamics may also enhance the
transport capacity of the system even when lane formation is suppressed.Comment: 25 pages, 17 figures, 2 table
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