11,962 research outputs found
Phosphoproteins associated with cyclic nucleotide stimulation of ciliary motility in Paramecium
Permeabilized, MgATP-reactivated cells of Paramecium (models) respond to cyclic AMP and cyclic GMP by increasing forward swimming speed. In association with the motile response, cyclic AMP and 8-bromo-cyclic GMP (8-Br-cyclic GMP) stimulated protein phosphorylation. Cyclic AMP addition to permeabilized cells reproducibly stimulated the phosphorylation of 10 proteins, ranging in molecular weight from 15 to 110K (K = 10^3 M_r). 8-Br-cyclic GMP, which selectively activates the cyclic GMP-dependent protein kinase of Paramecium, stimulated the phosphorylation of a subset of the proteins phosphorylated by cyclic AMP. Ca^(2+) addition caused backward swimming and stimulated the phosphorylation of four substrates, including a 25K target that may also be phosphorylated in response to cyclic nucleotide addition. Ba^(2+) and Sr^(2+) also induced backward swimming, but did not cause detectable phosphorylation. To identify ciliary targets of cyclic nucleotide-dependent protein kinase activity, permeabilized cells were deciliated following reactivation of motility with Mg-[y-^(32)P]ATP in the presence or absence of cyclic nucleotide. Soluble proteins of the deciliation supernatant were enriched in 15 cyclic AMP-stimulated phosphoproteins, ranging in molecular weight from 15 to 95K. Most of the ciliary substrates were axonemal and could be released by high salt solution. A 29K protein that copurified in sucrose gradients with the 22S dynein, and a high molecular weight protein (greater than 300K) in the 19 S region were phosphorylated when cyclic AMP was added to permeabilized, motile cells. These data suggest that regulation of ciliary motility by cyclic AMP may include phosphorylation of dynein-associated proteins
Realization of a Laser Cooled Microwave Power Standard (conference digest)
We demonstrate the feasibility of a novel microwave power standard based on
the electromagnetic interaction with cold atoms. Under the effect of the
radiation, the internal state populations will undergo a Rabi oscillation. The
measurement of its frequency will allow the determination of the
electromagnetic field strength.Comment: 2 pages, 1 figur
Accuracy of an Atomic Microwave Power Standard
We have built an atomic microwave power standard based on the electromagnetic
interaction with laser-cooled atoms. The atoms traversed a waveguide
transmission line, and under the effect of the radiation, the internal state
populations underwent a Rabi flopping oscillation. Measurement of the
oscillation frequency allowed the determination of the incident microwave
power. As many of 60 oscillations were observed over a dynamic range of 20 dB
and the standard deviation of the measurements was about 0.02%. The measured
frequency was compared to a calculated one and an agreement of 1.3% with an
uncertainty of 5% (rectangular) was found.Comment: 5 figure
CONNECTING TAXES AND WILLINGNESS TO PAY FOR FARMLAND PROTECTION: A COMPARISON OF LOCAL AND STATE FUNDED ALTERNATIVES IN NEW YORK
The costs of tax relief for New York agricultural landowners is compared with the willingness-to-pay for farmland protection as measured in valuation research. Under an income tax rebate, the program cost is positively related with the perceived household benefits, whereas this trend is reversed under a local property tax exemption.Agricultural and Food Policy, Public Economics,
Personal Property - Gifts Causa Mortis - Effect of Informal Writing Where There is No Actual Delivery
Prior to entering the hospital to undergo a serious operation, the decedent wrote an informal note to her husband telling him where he would find some money, a bank passbook, and a building and loan association stock book, which were hidden in their home. The note stated that this property was his. While the wife was under ether on the operating table, her husband found the note, after being directed to its location by a friend of the wife, and took possession of the items referred to. The wife did not recover consciousness and subsequently died. In an action by the personal representatives of the decedent to recover possession of the property, the trial court found that there was not sufficient delivery to perfect a gift causa mortis. The appellate division of the Superior Court reversed. On certification to the Supreme Court of New Jersey, held, reversed, three justices dissenting. An informal ·writing does not satisfy the separate and distinct requirement of delivery for a gift causa mortis. Foster v. Reiss, 18 N.J. 41, 112 A. (2d) 553 (1955)
Localization transitions in non-Hermitian quantum mechanics
We study the localization transitions which arise in both one and two
dimensions when quantum mechanical particles described by a random
Schr\"odinger equation are subjected to a constant imaginary vector potential.
A path-integral formulation relates the transition to flux lines depinned from
columnar defects by a transverse magnetic field in superconductors. The theory
predicts that the transverse Meissner effect is accompanied by stretched
exponential relaxation of the field into the bulk and a diverging penetration
depth at the transition.Comment: 4 pages (latex) with 3 figures (epsf) embedded in the text using the
style file epsf.st
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