17,026 research outputs found
SIC1 is ubiquitinated in vitro by a pathway that requires CDC4, CDC34, and cyclin/CDK activities
Traversal from G1 to S-phase in cycling cells of budding yeast is dependent on the destruction of the S-phase cyclin/CDK inhibitor SIC1. Genetic data suggest that SIC1 proteolysis is mediated by the ubiquitin pathway and requires the action of CDC34, CDC4, CDC53, SKP1, and CLN/CDC28. As a first step in defining the functions of the corresponding gene products, we have reconstituted SIC1 multiubiquitination in DEAE-fractionated yeast extract. Multiubiquitination depends on cyclin/CDC28 protein kinase and the CDC34 ubiquitin-conjugating enzyme. Ubiquitin chain formation is abrogated in cdc4ts mutant extracts and assembly restored by the addition of exogenous CDC4, suggesting a direct role for this protein in SIC1 multiubiquitination. Deletion analysis of SIC1 indicates that the N-terminal 160 residues are both necessary and sufficient to serve as substrate for CDC34-dependent ubiquitination. The complementary C-terminal segment of SIC1 binds to the S-phase cyclin CLB5, indicating a modular structure for SIC1
Incompressible Turbulence as Nonlocal Field Theory
It is well known that incompressible turbulence is nonlocal in real space
because sound speed is infinite in incompressible fluids. The equation in
Fourier space indicates that it is nonlocal in Fourier space as well. Contrast
this with Burgers equation which is local in real space. Note that the sound
speed in Burgers equation is zero. In our presentation we will contrast these
two equations using nonlocal field theory. Energy spectrum and renormalized
parameters will be discussed.Comment: 7 pages; Talk presented in Conference on "Perspectives in Nonlinear
Dynamics (PNLD 2004)" held in Chennai, 200
Dynamics of interacting quintessence
In this paper, we investigate coupled quintessence with scaling potential
assuming specific forms of the coupling as namely, ,
and , and
present phase space analysis for three different interacting models. We focus
on the attractor solutions that can give rise to late time acceleration with
of order unity in order to alleviate the coincidence
problem.Comment: 11 pages, 3 figures, matches with the published versio
Complexing of Metallic Ions with Organic Acids & Their Applications To Analytical Problems
in solutions containing copper and arsenic or antimony, the method of complexing the metallic ions and their estimation have been describe3
Participatory cotton breeding for organic and low input farming in Central India
Up to 80% of world’s organic cotton is produced in India. However, involved producers are facing increased difficulties to find suitable cultivars. Few hybrids selected for high input farming and genetically-modified (GM) cotton, which is explicitly excluded in organic farming, are presently dominating the Indian seed market. In addition farmers have lost their traditional knowledge on seed production and hybrid seed needs to be purchased each season
Efficient absolute aspect determination of a balloon borne far infrared telescope using a solid state optical photometer
The observational and operational efficiency of the TIFR 1 meter balloon
borne far infrared telescope has been improved by incorporating a multielement
solid state optical photometer (SSOP) at the Cassegrain focus of the telescope.
The SSOP is based on a 1-D linear photo diode array (PDA). The online and
offline processing schemes of the PDA signals which have been developed, lead
to improvement in the determination of absolute telescope aspect (
0\farcm8), which is very crucial for carrying out the observations as well as
offline analysis. The SSOP and its performance during a recent balloon flight
are presented here.Comment: To appear in the February 2000 issue of the PAS
Energy fluxes in helical magnetohydrodynamics and dynamo action
Renormalized viscosity, renormalized resistivity, and various energy fluxes
are calculated for helical magnetohydrodynamics using perturbative field
theory. The calculation is to first-order in perturbation. Kinetic and magnetic
helicities do not affect the renormalized parameters, but they induce an
inverse cascade of magnetic energy. The sources for the the large-scale
magnetic field have been shown to be (1) energy flux from large-scale velocity
field to large-scale magnetic field arising due to nonhelical interactions, and
(2) inverse energy flux of magnetic energy caused by helical interactions.
Based on our flux results, a premitive model for galactic dynamo has been
constructed. Our calculations yields dynamo time-scale for a typical galaxy to
be of the order of years. Our field-theoretic calculations also reveal
that the flux of magnetic helicity is backward, consistent with the earlier
observations based on absolute equilibrium theory.Comment: REVTEX4; A factor of 2 corrected in helicit
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