265 research outputs found
Effect of Corn Stalk Grazing and Baling on Cattle Performance and Irrigation Needs
The effects of removing corn residue by grazing and baling on continuous corn production were investigated. Initial data showed a trend toward keeping more water in the soil in the treatment with the most residue left on the field (no grazing or baling), but there was no effect of either grazing or baling on subsequent corn yield. Water conservation resulting from maintaining residue on the field may help reduce pumping costs or increase yields when water is limited. However, this benefit is likely to be outweighed by feed cost savings or grazing rental income, and good cow performance
Effect of Grazing Corn Residue on Corn and Soybean Yields
Grazing corn residue in the fall/winter or spring in either a corn-soybean rotation or a continuous corn system shows generally positive effects on yields. Soybean yields for both fall/winter and spring-grazed corn residue when compared to ungrazed corn residue in a corn followed by soybean rotation show an increase in yields
Effect of Grazing Corn Residue on Corn and Soybean Yields
Grazing corn residue in the fall/winter or spring in either a corn-soybean rotation or a continuous corn system shows generally positive effects on yields. Soybean yields for both fall/winter and spring-grazed corn residue when compared to ungrazed corn residue in a corn followed by soybean rotation show an increase in yields
Evidence for the inside-out growth of the stellar mass distribution in galaxy clusters since z ~ 1
International audienceWe study the radial number density and stellar mass density distributions of satellite galaxies in a sample of 60 massive clusters at 0.04 <z< 0.26 selected from the Multi-Epoch Nearby Cluster Survey (MENeaCS) and the Canadian Cluster Comparison Project (CCCP). In addition to ~10 000 spectroscopically confirmed member galaxies, we use deep ugri-band imaging to estimate photometric redshifts and stellar masses, and then statistically subtract fore- and background sources using data from the COSMOS survey. We measure the galaxy number density and stellar mass density distributions in logarithmically spaced bins over 2 orders of magnitude in radial distance from the BCGs. For projected distances in the range 0.1 <R/R200< 2.0, we find that the stellar mass distribution is well-described by an NFW profile with a concentration of c = 2.03 ± 0.20. However, at smaller radii we measure a significant excess in the stellar mass in satellite galaxies of about 1011M⊙ per cluster, compared to these NFW profiles. We do obtain good fits to generalised NFW profiles with free inner slopes and to Einasto profiles. To examine how clusters assemble their stellar mass component over cosmic time, we compare this local sample to the GCLASS cluster sample at z ~ 1, which represents the approximate progenitor sample of the low-z clusters. This allows for a direct comparison, which suggests that the central parts (R< 0.4 Mpc) of the stellar mass distributions of satellites in local galaxy clusters are already in place at z ~ 1, and contain sufficient excess material for further BCG growth. Evolving towards z = 0, clusters appear to assemble their stellar mass primarily onto the outskirts, making them grow in an inside-out fashion
The Phase Space and Stellar Populations of Cluster Galaxies at z ~ 1: Simultaneous Constraints on the Location and Timescale of Satellite Quenching
We investigate the velocity vs. position phase space of z ~ 1 cluster
galaxies using a set of 424 spectroscopic redshifts in 9 clusters drawn from
the GCLASS survey. Dividing the galaxy population into three categories:
quiescent, star-forming, and poststarburst, we find that these populations have
distinct distributions in phase space. Most striking are the poststarburst
galaxies, which are commonly found at small clustercentric radii with high
clustercentric velocities, and appear to trace a coherent ``ring" in phase
space. Using several zoom simulations of clusters we show that the coherent
distribution of the poststarbursts can be reasonably well-reproduced using a
simple quenching scenario. Specifically, the phase space is best reproduced if
satellite quenching occurs on a rapid timescale (0.1 < tau_{Q} < 0.5 Gyr) after
galaxies make their first passage of R ~ 0.5R_{200}, a process that takes a
total time of ~ 1 Gyr after first infall. We compare this quenching timescale
to the timescale implied by the stellar populations of the poststarburst
galaxies and find that the poststarburst spectra are well-fit by a rapid
quenching (tau_{Q} = 0.4^{+0.3}_{-0.4} Gyr) of a typical star-forming galaxy.
The similarity between the quenching timescales derived from these independent
indicators is a strong consistency check of the quenching model. Given that the
model implies satellite quenching is rapid, and occurs well within R_{200},
this would suggest that ram-pressure stripping of either the hot or cold gas
component of galaxies are the most plausible candidates for the physical
mechanism. The high cold gas consumption rates at z ~ 1 make it difficult to
determine if hot or cold gas stripping is dominant; however, measurements of
the redshift evolution of the satellite quenching timescale and location may be
capable of distinguishing between the two.Comment: 10 pages, 4 figures, submitted to the Ap
Covariant description of inelastic electron--deuteron scattering:predictions of the relativistic impulse approximation
Using the covariant spectator theory and the transversity formalism, the
unpolarized, coincidence cross section for deuteron electrodisintegration,
, is studied. The relativistic kinematics are reviewed, and simple
theoretical formulae for the relativistic impulse approximation (RIA) are
derived and discussed. Numerical predictions for the scattering in the high
region obtained from the RIA and five other approximations are presented
and compared. We conclude that measurements of the unpolarized coincidence
cross section and the asymmetry , to an accuracy that will distinguish
between different theoretical models, is feasible over most of the wide
kinematic range accessible at Jefferson Lab.Comment: 54 pages and 24 figure
Branching Fractions of tau Leptons to Three Charged Hadrons
From electron-positron collision data collected with the CLEO detector
operating at CESR near \sqrt{s}=10.6 GeV, improved measurements of the
branching fractions for tau decays into three explicitly identified hadrons and
a neutrino are presented as {\cal
B}(\tau^-\to\pi^-\pi^+\pi^-\nu_\tau)=(9.13\pm0.05\pm0.46)%, {\cal B}(\tau^-\to
K^-\pi^+\pi^-\nu_\tau)=(3.84\pm0.14\pm0.38)\times10^{-3}, {\cal B}(\tau^-\to
K^-K^+\pi^-\nu_\tau)=(1.55\pm0.06\pm0.09)\times10^{-3}, and {\cal B}(\tau^-\to
K^-K^+K^-\nu_\tau)<3.7\times10^{-5} at 90% C.L., where the uncertainties are
statistical and systematic, respectively.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, to appear in Phys. Rev. Let
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