612 research outputs found
Hydrolyzed Tuna Meat By-Product Supplement for Juvenile Red Sea Bream, Pagrus major, and its Effect on Growth, Enzyme Activity, Plasma Parameters, and Apparent Nutrient Digestibility
A growth experiment was conducted on juvenile red sea bream, Pagrus major to investigate the effect of the inclusion in fish diets, of tuna meat by-product hydrolysate which was processed through enzymatic hydrolysis using a commercially available enzyme, derived from Bacillus subtilis. Six experimental diets were formulated in the experiment. Three diets contained 50, 150 and 250 g/kg of TPM-H (tuna meat by-product hydrolysate), and two diets with the unprocessed TPM (tuna meat by-product) at an inclusion level of 50 and 250 g/kg. A control diet was formulated without any addition of the test ingredients. Treatment diets were fed ad libitum to juvenile fish with an initial average body weight of 0.81 ±0.13 g for 56 days. Results of the feeding trial suggest that the inclusion of TPM-H at 250 g/kg in fish diets improved body weight gain rate (3271.58%), feed intake (24.55 g/fish/56 days) and feed conversion efficiency (1.12) of the fish. Apparent nutrient digestibility of hydrolyzed tuna meat by-product improved compared to the unhydrolyzed ingredient. These results suggest that TPM processed as hydrolysates can be efficiently utilized by fish
Review of Methods of Power-Spectrum Analysis as Applied to Super-Kamiokande Solar Neutrino Data
To help understand why different published analyses of the Super-Kamiokande
solar neutrino data arrive at different conclusions, we have applied six
different methods to a standardized problem. The key difference between the
various methods rests in the amount of information that each processes. A
Lomb-Scargle analysis that uses the mid times of the time bins and ignores
experimental error estimates uses the least information. A likelihood analysis
that uses the start times, end times, and mean live times, and takes account of
the experimental error estimates, makes the greatest use of the available
information. We carry out power-spectrum analyses of the Super-Kamiokande 5-day
solar neutrino data, using each method in turn, for a standard search band (0
to 50 yr-1). For each method, we also carry out a fixed number (10,000) of
Monte-Carlo simulations for the purpose of estimating the significance of the
leading peak in each power spectrum. We find that, with one exception, the
results of these calculations are compatible with those of previously published
analyses. (We are unable to replicate Koshio's recent results.) We find that
the significance of the peaks at 9.43 yr-1 and at 43.72 yr-1 increases
progressively as one incorporates more information into the analysis procedure.Comment: 21 pages, 25 figure
Observing Supernova Neutrino Light Curves with Super-Kamiokande. III. Extraction of Mass and Radius of Neutron Stars from Synthetic Data
Neutrinos are guaranteed to be observable from the next Galactic supernova (SN). Optical light and gravitational waves are also observable, but may be difficult to observe if the location of the SN in the Galaxy or the details of the explosion are unsuitable. The key to observing the next SN is to first use neutrinos to understand various physical quantities and then link them to other signals. In this paper, we present Monte Carlo sampling calculations of neutrino events from Galactic SN explosions observed with Super-Kamiokande. The analytical solution of neutrino emission, which represents the long-term evolution of the neutrino light curve from SNe, is used as a theoretical template. It gives the event rate and event spectrum through inverse beta decay interactions with explicit model parameter dependence. Parameter estimation is performed on these simulated sample data by fitting least squares using the analytical solution. The results show that the mass, radius, and total energy of a remnant neutron star produced by an SN can be determined with an accuracy of ∼ 0.1 M⊙, ∼1 km, and ∼ 10⁵¹ erg, respectively, for a Galactic SN at 8 kpc
Effects of organic plant oils and role of oxidation on nutrient utilization in juvenile rainbow trout (Oncorhynchus mykiss)
The study compared the effect of four either fresh or force oxidized organic plant oils in diets for juvenile rainbow trout (Oncorhynchus mykiss) in which 47% of conventional LT fish meal protein was substituted by a mixture of 3 organic plant protein concentrates. Fish oil was completely substituted with either organic linseed oil; rape seed oil; sunflower oil or grape seed oil and evaluated based on feed intake, feed utilization, growth and digestibility. None of the plant oils affected feed intake and growth parameters. Organic plant oils had all a positive effect on lipid digestibility as compared with the fish oil based control diet, despite the very different FA profiles. The organic vegetable oils did not undergo autoxidation, as opposed to the fish oil control for which lipid digestibility was significantly negative influenced
Scintillation-only Based Pulse Shape Discrimination for Nuclear and Electron Recoils in Liquid Xenon
In a dedicated test setup at the Kamioka Observatory we studied pulse shape
discrimination (PSD) in liquid xenon (LXe) for dark matter searches. PSD in LXe
was based on the observation that scintillation light from electron events was
emitted over a longer period of time than that of nuclear recoil events, and
our method used a simple ratio of early to total scintillation light emission
in a single scintillation event. Requiring an efficiency of 50% for nuclear
recoil retention we reduced the electron background to 7.7\pm1.1(stat)\pm1.2
0.6(sys)\times10-2 at energies between 4.8 and 7.2 keVee and to
7.7\pm2.8(stat)\pm2.5 2.8(sys)\times10-3 at energies between 9.6 and 12 keVee
for a scintillation light yield of 20.9 p.e./keV. Further study was done by
masking some of that light to reduce this yield to 4.6 p.e./keV, the same
method results in an electron event reduction of 2.4\pm0.2(stat)\pm0.3
0.2(sys)\times10-1 for the lower of the energy regions above. We also observe
that in contrast to nuclear recoils the fluctuations in our early to total
ratio for electron events are larger than expected from statistical
fluctuations.Comment: 25 pages, 15 figure
Measurement of -ray production via neutron-O reaction using a 77 MeV quasi-monoenergetic neutron beam
Understanding of -ray production via neutron interactions on oxygen
is essential for the study of neutrino neutral-current quasielastic
interactions in water Cherenkov detectors. A measurement of -ray
production from such reactions was performed using a 77~MeV quasi-monoenergetic
neutron beam. Several -ray peaks, which are expected to come from
neutron- reactions, are observed and production cross sections
are measured for nine -ray components of energies between 2 and 8~MeV.
These are the first measurements at this neutron energy using a nearly
monoenergitic beam.Comment: 16 pages, 20 figures, 4 table
Distillation of Liquid Xenon to Remove Krypton
A high performance distillation system to remove krypton from xenon was
constructed, and a purity level of Kr/Xe = was
achieved. This development is crucial in facilitating high sensitivity low
background experiments such as the search for dark matter in the universe.Comment: 15 pages, 11 figure
Self-shielding effect of a single phase liquid xenon detector for direct dark matter search
Liquid xenon is a suitable material for a dark matter search. For future
large scale experiments, single phase detectors are attractive due to their
simple configuration and scalability. However, in order to reduce backgrounds,
they need to fully rely on liquid xenon's self-shielding property. A prototype
detector was developed at Kamioka Observatory to establish vertex and energy
reconstruction methods and to demonstrate the self-shielding power against
gamma rays from outside of the detector. Sufficient self-shielding power for
future experiments was obtained.Comment: 8 pages, 8 figure
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Search for Solar Axions Produced in Reaction with Borexino Detector
A search for 5.5-MeV solar axions produced in the reaction was performed using the Borexino detector. The Compton
conversion of axions to photons, ; the
axio-electric effect, ; the decay of axions into
two photons, ; and inverse Primakoff conversion on
nuclei, , are considered. Model independent
limits on axion-electron (), axion-photon (), and
isovector axion-nucleon () couplings are obtained: and at 1 MeV (90% c.l.). These limits are
2-4 orders of magnitude stronger than those obtained in previous
laboratory-based experiments using nuclear reactors and accelerators.Comment: 11 pages, 7 figures, submitted to Phys.Rev.
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