3,310 research outputs found
Economic Evaluation of Agricultural Research in Australia and New Zealand - A workshop held in conjunction with the 40th annual conference of the Australian Agricultural and Resource Economics Society 11-16 February 1996, Melbourne, Australia
Research and Development/Tech Change/Emerging Technologies,
Measuring Galaxy Environments with Deep Redshift Surveys
We study the applicability of several galaxy environment measures
(n^th-nearest-neighbor distance, counts in an aperture, and Voronoi volume)
within deep redshift surveys. Mock galaxy catalogs are employed to mimic
representative photometric and spectroscopic surveys at high redshift (z ~ 1).
We investigate the effects of survey edges, redshift precision, redshift-space
distortions, and target selection upon each environment measure. We find that
even optimistic photometric redshift errors (\sigma_z = 0.02) smear out the
line-of-sight galaxy distribution irretrievably on small scales; this
significantly limits the application of photometric redshift surveys to
environment studies. Edges and holes in a survey field dramatically affect the
estimation of environment, with the impact of edge effects depending upon the
adopted environment measure. These edge effects considerably limit the
usefulness of smaller survey fields (e.g. the GOODS fields) for studies of
galaxy environment. In even the poorest groups and clusters, redshift-space
distortions limit the effectiveness of each environment statistic; measuring
density in projection (e.g. using counts in a cylindrical aperture or a
projected n^th-nearest-neighbor distance measure) significantly improves the
accuracy of measures in such over-dense environments. For the DEEP2 Galaxy
Redshift Survey, we conclude that among the environment estimators tested the
projected n^th-nearest-neighbor distance measure provides the most accurate
estimate of local galaxy density over a continuous and broad range of scales.Comment: 17 pages including 16 figures, accepted to Ap
Measuring the Cosmic Equation of State with Counts of Galaxies
The classical dN/dz test allows the determination of fundamental cosmological
parameters from the evolution of the cosmic volume element. This test is
applied by measuring the redshift distribution of a tracer whose evolution in
number density is known. In the past, ordinary galaxies have been used as such
a tracer; however, in the absence of a complete theory of galaxy formation,
that method is fraught with difficulties. In this paper, we propose studying
instead the evolution of the apparent abundance of dark matter halos as a
function of their circular velocity, observable via the linewidths or rotation
speeds of visible galaxies. Upcoming redshift surveys will allow the linewidth
distribution of galaxies to be determined at both z~1 and the present day. In
the course of studying this test, we have devised a rapid, improved
semi-analytic method for calculating the circular velocity distribution of dark
halos based upon the analytic mass function of Sheth et al. (1999) and the
formation time distribution of Lacey & Cole (1993). We find that if selection
effects are well-controlled and minimal external constraints are applied, the
planned DEEP Redshift Survey should allow the measurement of the cosmic
equation-of-state parameter w to 10% (as little as 3% if Omega_m has been
well-determined from other observations). This type of test has the potential
also to provide a constraint on any evolution of w such as that predicted by
``tracker'' models.Comment: 4 pages plus 3 embedded figures; version approved by Ap. J. Letters.
A greatly improved error analysis has been added, along with a figure showing
complementarity to other cosmological test
Estrous expression of sows after altered suckling and boar exposure
In two different experiments, we studied the influence of: 1) separating litters from their dams (altered suckling) during the last 8 days of lactation, which included a change in housing and social interaction with other sows; 2) providing boar exposure (1 hr/d); and 3) parity on the ability of sows to come into heat during lactation and after weaning. Our studies indicated that: 1) 6 hr of altered suckling and 1 hr of boar exposure may shorten the interval to heat for sows that express estrus during lactation, but 3 hr of altered suckling and 1 h of boar exposure are sufficient to induce estrus in 65 to 79% of the sows; 2) boar exposure (1 hr /day) of sows is not sufficient to induce estrus during lactation; 3) pre weaning boar exposure (1 hr/day) reduced intervals to heat after weaning; and 4) breed composition and season may alter the responsiveness of sows to treatments that induce estrus during lactation and after weaning.; Swine Day, Manhattan, KS, November 19, 198
Estrous synchronization and scheduled artificial insemination for gilts
Gilts were artificially inseminated on the fifth, sixth and seventh days after estrous synchronization with altrenogest (scheduled AI). Contemporary controls also were synchronized but were checked for estrus twice daily. Scheduled AI gilts had farrowing rates and litter sizes similar to controls. Altrenogest is not presently available to pork producers but these results suggest that it could be used in combination with artificial insemination to schedule breeding according to a predetermined schedule.; Swine Day, Manhattan, KS, November 10, 198
Fertility with artificial insemination: gilts that lock on the insemination spirette vs. those that don\u27t
KSU breeding records show a higher farrowing rate for gilts that lock on the insemination spirette at both inseminations as opposed to gilts that lock at one insemination or at neither insemination. Continued research is focusing on factors affecting female response to insemination and fertility.; Swine Day, Manhattan, KS, November 11, 198
Constraining anomalous Higgs boson couplings to virtual photons
We present a study of Higgs boson production in vector boson fusion and in
association with a vector boson and its decay to two vector bosons, with a
focus on the treatment of virtual loops and virtual photons. Our analysis is
performed with the JHU generator framework. Comparisons are made to several
other frameworks, and the results are expressed in terms of an effective field
theory. New features of this study include a proposal on how to handle
singularities involving Higgs boson decays to light fermions via photons,
calculation of the partial Higgs boson width in the presence of anomalous
couplings to photons, a comparison of the next-to-leading-order electroweak
corrections to effects from effective couplings, and phenomenological
observations regarding the special role of intermediate photons in analysis of
LHC data in the effective field theory framework. Some of these features are
illustrated with projections for experimental measurements with the full LHC
and HL-LHC datasets.Comment: 32 pages, 14 figure
On the Origin of [OII] Emission in Red Sequence and Post-starburst Galaxies
We investigate the emission-line properties of galaxies with red rest-frame
colors using spectra from SDSS DR4. Emission lines are detected in more than
half of the red galaxies. We focus on the relationship between two emission
lines commonly used as star formation rate indicators: Ha 6563 and [OII] 3727.
There is a strong bimodality in [OII]/Ha ratio in the full SDSS sample which
closely corresponds to the bimodality in rest-frame color. Nearly all of the
line-emitting red galaxies have line ratios typical of various types of AGN --
most commonly LINERs, a small fraction of transition objects and, more rarely,
Seyferts. Only ~6% of red galaxies display star-forming line ratios. A straight
line in the [OII]-Ha equivalent width plane separates LINER-like galaxies from
other categories. Quiescent galaxies with no detectable emission lines and
LINER-like galaxies combine to form a single, tight red sequence in
color-magnitude-concentration space. [OII] EWs in LINER- and AGN-like galaxies
can be as large as in star-forming galaxies. Thus, unless objects with
AGN/LINER-like line ratios are excluded, [OII] emission cannot be used directly
as a proxy for star formation rate. Lack of [OII] emission is generally used to
indicate lack of star formation when post-starburst galaxies are selected at
high redshift. Our results imply, however, that these samples have been cut on
AGN properties as well as star formation, and therefore may provide seriously
incomplete sets of post-starburst galaxies. Furthermore, post-starburst
galaxies identifed in SDSS by requiring minimal Ha EW generally exhibit weak
but nonzero line emission with ratios typical of AGNs; few of them show
residual star formation. This suggests that most post-starbursts may harbor
AGNs/LINERs.Comment: 21 pages, 15 figures. v2: Added 4 new figures and updated many;
extended text. No conclusions change. v3: minor modifications and figure
updates to match version accepted by Ap
AEGIS: Chandra Observation of DEEP2 Galaxy Groups and Clusters
We present a 200 ksec Chandra observation of seven spectroscopically
selected, high redshift (0.75 < z < 1.03) galaxy groups and clusters discovered
by the DEEP2 Galaxy Redshift Survey in the Extended Groth Strip (EGS). X-ray
emission at the locations of these systems is consistent with background. The
3-sigma upper limits on the bolometric X-ray luminosities (L_X) of these
systems put a strong constraint on the relation between L_X and the velocity
dispersion of member galaxies sigma_gal at z~1; the DEEP2 systems have lower
luminosity than would be predicted by the local relation. Our result is
consistent with recent findings that at high redshift, optically selected
clusters tend to be X-ray underluminous. A comparison with mock catalogs
indicates that it is unlikely that this effect is entirely caused by a
measurement bias between sigma_gal and the dark matter velocity dispersion.
Physically, the DEEP2 systems may still be in the process of forming and hence
not fully virialized, or they may be deficient in hot gas compared to local
systems. We find only one possibly extended source in this Chandra field, which
happens to lie outside the DEEP2 coverage.Comment: 5 pages, 3 figures. Accepted for publication in AEGIS ApJ Letters
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