2,237 research outputs found
Improved flux limits for neutrinos with energies above 10 eV from observations with the Westerbork Synthesis Radio Telescope
Particle cascades initiated by ultra-high energy (UHE) neutrinos in the lunar
regolith will emit an electromagnetic pulse with a time duration of the order
of nano seconds through a process known as the Askaryan effect. It has been
shown that in an observing window around 150 MHz there is a maximum chance for
detecting this radiation with radio telescopes commonly used in astronomy. In
50 hours of observation time with the Westerbork Synthesis Radio Telescope
array we have set a new limit on the flux of neutrinos, summed over all
flavors, with energies in excess of eV.Comment: Submitted to Phys. Rev. Let
Consequences of wall stiffness for a beta-soft potential
Modifications of the infinite square well E(5) and X(5) descriptions of
transitional nuclear structure are considered. The eigenproblem for a potential
with linear sloped walls is solved. The consequences of the introduction of
sloped walls and of a quadratic transition operator are investigated.Comment: RevTeX 4, 8 pages, as published in Phys. Rev.
Photoproduction of eta meson within a coupled-channels K-matrix approach
We investigate photoproduction of eta mesons off protons and neutrons within
a coupled-channels effective-Lagrangian method which is based on the K-matrix
approach. The two-body final channels included are pi-N, eta-N, phi-N, rho-N,
gamma-N, K-Lambda, and K-Sigma. Non-resonant meson-baryon interactions are
included in the model via nucleon intermediate states in the s- and u-channels,
meson exchanges in the t-channel amplitude and the u-channel resonances. The
nucleon resonances S_{11}(1535), S_{11}(1650), S_{31}(1620), P_{11}(1440),
P_{11}(1710), P_{13}(1720), P_{33}(1232), P_{33}(1600), D_{13}(1520),
D_{13}(1700), and D_{33}(1700) are included explicitly in calculations. Our
model describes simultaneously the available data as well on total and
differential cross sections as on beam and target asymmetries. This holds for
the p(gamma,eta)p reaction for photon energies ranging from very close to
threshold to up to 3 GeV. The polarization observables show strong sensitivity
to resonances that otherwise contribute only weakly to the total cross section.
It is found that the pronounced bump-like structure seen in the excitation
function of the n(gamma,eta)n cross section at gamma energies around 1 GeV, can
be explained by the interference effects of S_{11}, P_{11} and P_{13} resonance
contributions.Comment: 36 pages, 14 figures, one new figure added, discussions revised,
version to appear in Phys. Rev.
Los bijvoeren van gemalen tarwe bij biggen gespeende
Het vervangen van 25% van het mengvoer door gemalen tarwe is bij gespeende biggen mogelijk met behoud van technische resultaten en gezondheid
Enzymtoevoeging aan biggenvoer
Het toevoegen van de enzymen beta-glucanase en xylanase (Porzyme-8 100e) aan biggenvoer met 30% gerst en 15% tarwe(gries) heeft géén positief effect op de technische resultaten, de uitval en het aantal veterinair behandelde gespeende biggen
Het *STAR-concept in vleesvarkensvoer
Het toevoegen van de structuurrijke componenten tarwekorrel en niet-ontsloten strobrok volgens *STAR-concept aan vleesvarkensvoer verlaagt het aantal varkens met maagslijmvliesaandoeningen. Het effect op de mesterijresultaten is gering
Prospects for GMRT to Observe Radio Waves from UHE Particles Interacting with the Moon
Ultra high energy (UHE) particles of cosmic origin impact the lunar regolith
and produce radio signals through Askaryan effect, signals that can be detected
by Earth based radio telescopes. We calculate the expected sensitivity for
observation of such events at the Giant Metrewave Radio Telescope (GMRT), both
for UHE cosmic rays (CR) and UHE neutrino interactions. We find that for 30
days of observation time a significant number of detectable events is expected
above eV for UHECR or neutrino fluxes close to the current limits.
Null detection over a period of 30 days will lower the experimental bounds on
UHE particle fluxes by magnitudes competitive to both present and future
experiments at the very highest energies.Comment: 21 pages, 9 figure
Voedingsonderzoek met tarwe en perspulp bij vleesvarkens
Begin 1997 starten twee nieuwe voedingsproeven bij vleesvarkens. Het eerste onderzoek richt zich op de vraag of er verschil in technische resultaten ontstaat wanneer 50% tarwe los wordt bijgevoerd of 50% tarwe in het mengvoer wordt geperst. Het tweedeonderzoek richt zich op het voeren van 10% perspulp in brijvoer- én droogvoerrantsoenen
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