418 research outputs found
Seed Cleaning and Treating Pays Off
Seed cleaning and treating is imperative- whether you do it yourself or have it done for you. It pays off in increased stands, fewer weeds and less trouble from certain diseases in oats, wheat, barley, flax, and rye
RNA Polymerase-Binding and Transcription Initiation Sites Upstream of the Methyl Reductase Operon of Methanococcus vannielii
RNA Polymerase, purified from Methanococcus vannielii, was shown by exonuclease III footprinting to bind
to a 49-base-pair (bp) region of DNA in the intergenic region upstream of mcrB. Sl nuclease protection
experiments demonstrated that transcription Initiation in vivo occurs within this region at 32 or 33 bp 5' to the
A T G translation initiation codon of mcrB and 19 or 20 bp 3' to a T A T A box
Farm Disease Outlook for 1953
Plant diseases have given us trouble for a long time, and they\u27ll be with us in one form or another in 1953. Here are the highlights of what may happen under different conditions and, in turn, what to do
Synaptic motility and functional stability in the whisker cortex
The high motility of synaptic weights raises the question of how the brain
can retain its functionality in the face of constant synaptic remodeling. Here
we used the whisker system of rats and mice to study the interplay between
synaptic plasticity (motility) and the transmission of sensory signals
downstream.
Rats and mice probe their surroundings by rhythmically moving their whiskers
back and forth. The azimuthal position of a whisker can be estimated from the
activity of whisking neurons that respond selectively to a preferred phase
along the whisking cycle. These preferred phases are widely distributed on the
ring. However, simple models for the transmission of the whisking signal
downstream predict a distribution of preferred phases that is an order of
magnitude narrower than empirically observed. Here, we suggest that synaptic
plasticity in the form of spike-timing-dependent plasticity (STDP) may provide
a solution to this conundrum. This hypothesis is addressed in the framework of
a modeling study that investigated the STDP dynamics in a population of
synapses that propagates the whisking signal downstream.
The findings showed that for a wide range of parameters, STDP dynamics do not
relax to a fixed point. As a result, the preferred phases of downstream neurons
drift in time at a non-uniform velocity which in turn, induces a non-uniform
distribution of the preferred phases of the downstream population. This
demonstrates how functionality, in terms of the distribution of preferred
phases, can be retained not simply despite, but because of the constant
synaptic motility. Our analysis leads to several key empirical predictions to
test this hypothesis
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