308 research outputs found
AI For Sheep Using Frozen-thawed Semen.
End of Project ReportInternational experience has been that cervical insemination of sheep with
frozen-thawed semen usually yields unacceptably low pregnancy rates (10
to 30%). An exceptional case has been Norway where non-return rates in
on-farm usage are around 60%. The objective of the work described in this
report was to develop an AI procedure for Irish conditions, based initially
on Norwegian protocols, using semen from individual rams. Such a
procedure would greatly facilitate and enhance genetic improvement
programmes for sheep.
The work undertaken had two separate aspects:-
(i) studies on semen, including processing and freezing methods,
laboratory evaluation of semen quality post thawing and the
relationship of in vitro evaluation to fertilisation rate in vivo
(ii) studies on pregnancy rate following AI in relation to issues such as
ram breed effects, effects of synchronisation, operator differences and
the role of ewe breed inducing the timing of ovulation and various
physical and physiological assessments of the cervix at AI.
The main results in relation to semen studies were that, while a range of
differential staining procedures could be used to objectively evaluate semen
with respect to proportion of live speramatozoa and the integrity of sperm
cells after thawing, these results were not useful as indicators of fertilisation
capacity in vivo. The in vitro fertilisation (IVF) of sheep oocytes recovered
from abattoir material gave promising results as a method for evaluating the
fertilisation capacity of frozen-thawed semen. The technique requires
further validation.Department of Agriculture, Food and the Marin
Unsettling play: perceptions of Agonistic Games
In this article, we propose Agonistic Games (AGs) as a serious games subcategory that can stimulate critical reflection on topics of dark heritage through multiperspectivity and unsettling play. We first discuss the emerging topic of agonism in memory studies, and then how games can be used to support its objectives. We then discuss the development of two original AGs: Endless Blitz and Umschlagplatz ’43. We explore whether these two AGs were perceived as capable of stimulating critical reflection by collecting data from visitors to the exhibition “Krieg. Macht. Sinn” at the Ruhr Museum in Germany where the games were installed, and from participants in an online course describing the games. From analysing data collected, we outline four factors inhibiting the capacity of AGs to stimulate critical reflection (topic, context, design, and assumptions about games) and propose strategies for overcoming these inhibitors. Our findings are valuable to scholars, game researchers, and designers, strengthening the foundations for the design and development of future AGs
Two-Dimensional Vortex Lattice Melting
We report on a Monte-Carlo study of two-dimensional Ginzburg-Landau
superconductors in a magnetic field which finds clear evidence for a
first-order phase transition characterized by broken translational symmetry of
the superfluid density. A key aspect of our study is the introduction of a
quantity proportional to the Fourier transform of the superfluid density which
can be sampled efficiently in Landau gauge Monte-Carlo simulations and which
satisfies a useful sum rule. We estimate the latent heat per vortex of the
melting transition to be where is the melting
temperature.Comment: 10 pages (4 figures available on request), RevTex 3.0, IUCM93-00
A-dependence of nuclear transparency in quasielastic A(e,e'p) at high Q^2
The A-dependence of the quasielastic A(e,e'p) reaction has been studied at
SLAC with H-2, C, Fe, and Au nuclei at momentum transfers Q^2 = 1, 3, 5, and
6.8 (GeV/c)^2. We extract the nuclear transparency T(A,Q^2), a measure of the
average probability that the struck proton escapes from the nucleus A without
interaction. Several calculations predict a significant increase in T with
momentum transfer, a phenomenon known as Color Transparency. No significant
rise within errors is seen for any of the nuclei studied.Comment: 5 pages incl. 2 figures, Caltech preprint OAP-73
Measurement of the branching fraction for
We have studied the leptonic decay of the resonance into tau
pairs using the CLEO II detector. A clean sample of tau pair events is
identified via events containing two charged particles where exactly one of the
particles is an identified electron. We find . The result is consistent with
expectations from lepton universality.Comment: 9 pages, RevTeX, two Postscript figures available upon request, CLNS
94/1297, CLEO 94-20 (submitted to Physics Letters B
Study of the B^0 Semileptonic Decay Spectrum at the Upsilon(4S) Resonance
We have made a first measurement of the lepton momentum spectrum in a sample
of events enriched in neutral B's through a partial reconstruction of B0 -->
D*- l+ nu. This spectrum, measured with 2.38 fb**-1 of data collected at the
Upsilon(4S) resonance by the CLEO II detector, is compared directly to the
inclusive lepton spectrum from all Upsilon(4S) events in the same data set.
These two spectra are consistent with having the same shape above 1.5 GeV/c.
From the two spectra and two other CLEO measurements, we obtain the B0 and B+
semileptonic branching fractions, b0 and b+, their ratio, and the production
ratio f+-/f00 of B+ and B0 pairs at the Upsilon(4S). We report b+/b0=0.950
(+0.117-0.080) +- 0.091, b0 = (10.78 +- 0.60 +- 0.69)%, and b+ = (10.25 +- 0.57
+- 0.65)%. b+/b0 is equivalent to the ratio of charged to neutral B lifetimes,
tau+/tau0.Comment: 14 page, postscript file also available at
http://w4.lns.cornell.edu/public/CLN
Measurement of the Decay Asymmetry Parameters in and
We have measured the weak decay asymmetry parameters (\aLC ) for two \LC\
decay modes. Our measurements are \aLC = -0.94^{+0.21+0.12}_{-0.06-0.06} for
the decay mode and \aLC = -0.45\pm 0.31 \pm
0.06 for the decay mode . By combining these
measurements with the previously measured decay rates, we have extracted the
parity-violating and parity-conserving amplitudes. These amplitudes are used to
test models of nonleptonic charmed baryon decay.Comment: 11 pages including the figures. Uses REVTEX and psfig macros. Figures
as uuencoded postscript. Also available as
http://w4.lns.cornell.edu/public/CLNS/1995/CLNS95-1319.p
Observation of the Charmed Baryon Decays to , , and
We have observed two new decay modes of the charmed baryon into
and using data collected with the
CLEO II detector. We also present the first measurement of the branching
fraction for the previously observed decay mode . The branching fractions for these three modes relative to
are measured to be , , and , respectively.Comment: 12 page uuencoded postscript file, postscript file also available
through http://w4.lns.cornell.edu/public/CLN
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