40,658 research outputs found
A biologically active peptide in the skin of lampreys (Eudontomyzon danfordi vladykovi). [Translation from: Z.Naturforsch. (B), 26(10), 1021-1023, 1971. ]
In recent years interest in the production and description of kinin-type substances has been greatly intensified. So, for example, bradykinin, phyllokinin, physalaemin, ranatensin and caerulein could be extracted from the skin of amphibians as well as. eledoisin out of the salivary glands of Eledon moschata. An examination of lampreys seemed to us particularly profitable in the search for the incidence of further kinins. Ammocoetes of different sizes and also adults of both sexes of the species Eudontomyzon danfordi vladykovi were studied in this research. This species is found in many tributaries of the Danube. Skin extracts were tested on on isolated rat uterus, rat duodenum, guinea pig ileum and rabbit jejunum, further tests were done in order to determine a peptide character of the biologically active substance
Long-range beam-beam experiments in the relativistic heavy ion collider
Long-range beam-beam effects are a potential limit to the LHC performance
with the nominal design parameters, and certain upgrade scenarios under
discussion. To mitigate long-range effects, current carrying wires parallel to
the beam were proposed and space is reserved in the LHC for such wires. Two
current carrying wires were installed in RHIC to study the effect of strong
long-range beam-beam effects in a collider, as well as test the compensation of
a single long-range interaction. The experimental data were used to benchmark
simulations. We summarize this work.Comment: 12 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects
in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201
Radiant heat exchange in a space environment Scientific technical report, 1 Feb. - 31 Jul. 1970
Spectral and directional surface property effects on radiant heat transfer in space environmen
Radiant heat exchange in a space environment Scientific technical report, 1 Aug. 1969 - 31 Jan. 1970
Spectral surface property effects on radiant heat transfer in aerospace environmen
High resolution frequency selective photochemistry of phycobilisomes at cryogenic temperatures
A Third Planet Orbiting HIP 14810
We present new precision radial velocities and a three-planet Keplerian orbit
fit for the V = 8.5, G5 V star HIP 14810. We began observing this star at Keck
Observatory as part of the N2K Planet Search Project. Wright et al. (2007)
announced the inner two planets to this system, and subsequent observations
have revealed the outer planet planet and the proper orbital solution for the
middle planet. The planets have minimum masses of 3.9, 1.3, and 0.6 M_Jup and
orbital periods of 6.67, 147.7, and 952 d, respectively. We have numerically
integrated the family of orbital solutions consistent with the data and find
that they are stable for at least 10^6 yr. Our photometric search shows that
the inner planet does not transit.Comment: ApJL, accepte
ZZE-Configuration of chromophore ß-153 in C-phycocyanin from Mastigocladus laminosus
The photochemistry of C-phycocyanin has been studied after denaturation in the dark. It shows
an irreversible reaction which has characteristics of a Ζ,Ζ,Ε- to Z,Z,Z-isomerization of dihydrobilins.
Its amplitude depends on the reaction conditions, with a maximum corresponding to 15%
conversion of one of the three PC chromophores. This chromophore is suggested to be ß-153, for
which recent X-ray data T. Schirmer, W. Bode, and R. Huber, J. Mol. Biol., submitted, show
ring D being highly twisted out of the plane of the other rings. During unfolding, there is thus a
probability of falling into the photochemically labile Z,Z,^-configuration
Six-dimensional weak-strong simulations of head-on beam-beam compensation in RHIC
To compensate the large beam-beam tune spread and beam-beam resonance driving
terms in the polarized proton operation in the Relativistic Heavy Ion Collider
(RHIC), we will introduce a low-energy DC electron beam into each ring to
collide head-on with the opposing proton beam. The device to provide the
electron beam is called an electron lens. In this article, using a 6-D
weak-strong-beam-beam interaction simulation model, we investigate the effects
of head-on beam-beam compensation with electron lenses on the proton beam
dynamics in the RHIC 250 GeV polarized proton operation. This article is
abridged from the published article [1].Comment: 5 pages, contribution to the ICFA Mini-Workshop on Beam-Beam Effects
in Hadron Colliders, CERN, Geneva, Switzerland, 18-22 Mar 201
An Introduction to Conformal Ricci Flow
We introduce a variation of the classical Ricci flow equation that modifies
the unit volume constraint of that equation to a scalar curvature constraint.
The resulting equations are named the Conformal Ricci Flow Equations because of
the role that conformal geometry plays in constraining the scalar curvature.
These equations are analogous to the incompressible Navier-Stokes equations of
fluid mechanics inasmuch as a conformal pressure arises as a Lagrange
multiplier to conformally deform the metric flow so as to maintain the scalar
curvature constraint. The equilibrium points are Einstein metrics with a
negative Einstein constant and the conformal pressue is shown to be zero at an
equilibrium point and strictly positive otherwise. The geometry of the
conformal Ricci flow is discussed as well as the remarkable analytic fact that
the constraint force does not lose derivatives and thus analytically the
conformal Ricci equation is a bounded perturbation of the classical
unnormalized Ricci equation. That the constraint force does not lose
derivatives is exactly analogous to the fact that the real physical pressure
force that occurs in the Navier-Stokes equations is a bounded function of the
velocity. Using a nonlinear Trotter product formula, existence and uniqueness
of solutions to the conformal Ricci flow equations is proven. Lastly, we
discuss potential applications to Perelman's proposed implementation of
Hamilton's program to prove Thurston's 3-manifold geometrization conjectures.Comment: 52 pages, 1 figur
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