690 research outputs found
Flow of Binary and Tertiary Mixtures of Waxes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66517/2/10.1177_00220345660450023101.pd
The production of gibberellin-like substances by Colletotrichum gloeosporioides associated with lupin anthracnose
The most characteristic symptoms of lupin (Lupinus spp.) anthracnose caused by the fungus Colletotrichum gloeosporioides, are twisting and bending of stems and petioles. These might be related to the production of gibberellin-like activity by the pathogen. The barley aleurone bioassay was used to determine whether two isolates of C. gloeosporioides could produce gibberellin-like substances. Ethyl acetate extracts from isolates SHK 2148 and SHK 1033, grown in liquid minimal medium, had gibberellin-like activities of 0.21 μg GA3 equivalents and >0.26μg GA3 equivalents per g dry mass of mycelium, respectively. Provided that the strong association between gibberellins and this specific pathogen/host interaction can be established, this knowledge may be helpful in screening lupin cultivars for anthracnose resistance
Differential Thermal Analysis of Commercial and Dental Waxes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67104/2/10.1177_00220345670460051701.pd
The distribution of transit durations for Kepler planet candidates and implications for their orbital eccentricities
‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at : http://iopscience.iop.org/ Copyright American Astronomical SocietyDoppler planet searches have discovered that giant planets follow orbits with a wide range of orbital eccentricities, revolutionizing theories of planet formation. The discovery of hundreds of exoplanet candidates by NASA's Kepler mission enables astronomers to characterize the eccentricity distribution of small exoplanets. Measuring the eccentricity of individual planets is only practical in favorable cases that are amenable to complementary techniques (e.g., radial velocities, transit timing variations, occultation photometry). Yet even in the absence of individual eccentricities, it is possible to study the distribution of eccentricities based on the distribution of transit durations (relative to the maximum transit duration for a circular orbit). We analyze the transit duration distribution of Kepler planet candidates. We find that for host stars with T > 5100 K we cannot invert this to infer the eccentricity distribution at this time due to uncertainties and possible systematics in the host star densities. With this limitation in mind, we compare the observed transit duration distribution with models to rule out extreme distributions. If we assume a Rayleigh eccentricity distribution for Kepler planet candidates, then we find best fits with a mean eccentricity of 0.1-0.25 for host stars with T ≤ 5100 K. We compare the transit duration distribution for different subsets of Kepler planet candidates and discuss tentative trends with planetary radius and multiplicity. High-precision spectroscopic follow-up observations for a large sample of host stars will be required to confirm which trends are real and which are the results of systematic errors in stellar radii. Finally, we identify planet candidates that must be eccentric or have a significantly underestimated stellar radius.Peer reviewedFinal Accepted Versio
Some closure operations in Zariski-Riemann spaces of valuation domains: a survey
In this survey we present several results concerning various topologies that
were introduced in recent years on spaces of valuation domains
β1-Adrenergic Receptor and Sphingosine- 1-Phosphate Receptor 1 Reciprocal Down-Regulation Influences Cardiac Hypertrophic Response and Progression Toward Heart Failure: Protective Role of S1PR1 Cardiac Gene Therapy
YesThe Sphingosine-1-phosphate receptor 1 (S1PR1) and β1-adrenergic receptor
(β1AR) are G protein-coupled receptors (GPCRs) expressed in the heart. These two GPCRs have
opposing actions on adenylyl cyclase due to differential G protein-coupling. Importantly, both of
these receptors can be regulated by the actions of GPCR kinase-2 (GRK2), which triggers
desensitization and down-regulation processes. Although, classical signaling paradigms suggest
that simultaneous activation of β1ARs and S1PR1s in a myocyte would simply be opposing action
on cAMP production, in this report we have uncovered a direct interaction between these two
receptors with a regulatory involvement of GRK2.
In HEK293 cells overexpressing both β1AR and S1PR1, we
demonstrate that β1AR down-regulation can occur after sphingosine 1-phosphate (S1PR1 agonist)
stimulation while S1PR1 down-regulation can be triggered by isoproterenol (βAR agonist)
treatment. This cross-talk between these two distinct GPCRs appears to have physiological
significance since they interact and show reciprocal regulation in mouse hearts undergoing chronic
βAR stimulation and also in a rat model of post-ischemic heart failure (HF).
We demonstrate that restoring cardiac plasma membrane levels of S1PR1
produce beneficial effects counterbalancing deleterious β1AR overstimulation in HF
Tracking azimuthons in nonlocal nonlinear media
We study the formation of azimuthons, i.e., rotating spatial solitons, in
media with nonlocal focusing nonlinearity. We show that whole families of these
solutions can be found by considering internal modes of classical non-rotating
stationary solutions, namely vortex solitons. This offers an exhaustive method
to identify azimuthons in a given nonlocal medium. We demonstrate formation of
azimuthons of different vorticities and explain their properties by considering
the strongly nonlocal limit of accessible solitons.Comment: 11 pages, 7 figure
Strange Meson Enhancement in PbPb Collisions
The NA44 Collaboration has measured yields and differential distributions of
K+, K-, pi+, pi- in transverse kinetic energy and rapidity, around the
center-of-mass rapidity in 158 A GeV/c Pb+Pb collisions at the CERN SPS. A
considerable enhancement of K+ production per pi is observed, as compared to
p+p collisions at this energy. To illustrate the importance of secondary hadron
rescattering as an enhancement mechanism, we compare strangeness production at
the SPS and AGS with predictions of the transport model RQMD.Comment: 11 pages, including 4 figures, LATE
Kepler-22b: A 2.4 Earth-radius Planet in the Habitable Zone of a Sun-like Star
A search of the time-series photometry from NASA's Kepler spacecraft reveals
a transiting planet candidate orbiting the 11th magnitude G5 dwarf KIC 10593626
with a period of 290 days. The characteristics of the host star are well
constrained by high-resolution spectroscopy combined with an asteroseismic
analysis of the Kepler photometry, leading to an estimated mass and radius of
0.970 +/- 0.060 MSun and 0.979 +/- 0.020 RSun. The depth of 492 +/- 10ppm for
the three observed transits yields a radius of 2.38 +/- 0.13 REarth for the
planet. The system passes a battery of tests for false positives, including
reconnaissance spectroscopy, high-resolution imaging, and centroid motion. A
full BLENDER analysis provides further validation of the planet interpretation
by showing that contamination of the target by an eclipsing system would rarely
mimic the observed shape of the transits. The final validation of the planet is
provided by 16 radial velocities obtained with HIRES on Keck 1 over a one year
span. Although the velocities do not lead to a reliable orbit and mass
determination, they are able to constrain the mass to a 3{\sigma} upper limit
of 124 MEarth, safely in the regime of planetary masses, thus earning the
designation Kepler-22b. The radiative equilibrium temperature is 262K for a
planet in Kepler-22b's orbit. Although there is no evidence that Kepler-22b is
a rocky planet, it is the first confirmed planet with a measured radius to
orbit in the Habitable Zone of any star other than the Sun.Comment: Accepted to Ap
Production of Lambda and Sigma^0 hyperons in proton-proton collisions
This paper reports results on simultaneous measurements of the reaction
channels pp -> pK+\Lambda and pp -> pK+\Sigma^0 at excess energies of 204, 239,
and 284 MeV (\Lambda) and 127, 162, and 207 MeV (\Sigma^0). Total and
differential cross sections are given for both reactions. It is concluded from
the measured total cross sections that the high energy limit of the cross
section ratio is almost reached at an excess energy of only about 200 MeV. From
the differential distributions observed in the overall CMS as well as in the
Jackson and helicity frames, a significant contribution of interfering nucleon
resonances to the \Lambda production mechanism is concluded while resonant
\Sigma^0-production seems to be of lesser importance and takes place only
through specific partial waves of the entrance channel. The data also indicate
that kaon exchange plays a minor role in the case of \Lambda- but an important
role for \Sigma^0-production. Thus the peculiar energy dependence of the
\Lambda-to-\Sigma^0 cross section ratio appears in a new light as its
explanation requires more than mere differences between the p\Lambda and the
p\Sigma^0 final state interaction. The data provide a benchmark for theoretical
models already available or yet to come.Comment: 18 pages, 10 figures; accepted by The European Physical Journal A
(EPJ A
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