1,545 research outputs found
Are artificial semi-dry wetlands efficient in wastewater treatment from different fish densities and for lettuce production?
This study aimed to determine artifcial semi-dry wetlands' performance to wastewater treatment from fish farming and Lactuca sativa production in an aquaponics system. This trial model observed the effects of different stocking biomass on the growth rate of Colossoma macropomum and yield of two L. sativa varieties. A factorial design consisting of three fish density treatments in quadruplicate and two Lettuces variety was used. Nine hundred and sixty fingerlings with 8.35±0.91 g were stocked at three stocking biomass treatments in quadruplicate: 40 fingerlings or 334 g m-3; 80 fingerlings 668 g m-3; 120 fingerlings or 1002 g m-3. Delice American Lettuce and Purple Crested Lettuce were cultured in the semi-dry wetlands. The fnal mass (g), consumed food, feed conversion ratio, and yield of fngerling were statistically diferent between the tested densities, but survival did not. The artificial semi-dry wetlands were efcient on water treatment and the recovery of nutrients in all fsh densities trials, and it has potential as support for lettuce production. The recovery of nutrients was shown on the increment of the number of leaves, total fresh mass (g), and lettuces yield by area (kg m-2) in both varieties of plants tested. Precocious fowering in 30% of lettuce varieties, incidence of mealybug and whitefly, temperature and defciency of calcium and magnesium were factors that may have compromised the full lettuce development. The aquaponics system eficiently treated the fsh efuent at the densities tested, being appropriate for fish farming and lettuces production
Produção de mudas de marmeleiro (Croton blanchetianus Baill - Euphorbiaceae).
Objetivou-se com este trabalho avaliar o efeito da auxina ácido indolbutírico no enraizamento de estacas da espécie
Open and Hidden Charm Production in 920 GeV Proton-Nucleus Collisions
The HERA-B collaboration has studied the production of charmonium and open
charm states in collisions of 920 GeV protons with wire targets of different
materials. The acceptance of the HERA-B spectrometer covers negative values of
xF up to xF=-0.3 and a broad range in transverse momentum from 0.0 to 4.8
GeV/c. The studies presented in this paper include J/psi differential
distributions and the suppression of J/psi production in nuclear media.
Furthermore, production cross sections and cross section ratios for open charm
mesons are discussed.Comment: 5 pages, 9 figures, to be published in the proceedings of the 6th
International Conference on Hyperons, Charm & Beauty Hadrons (BEACH04),
Chicago, IL, June 27 - July 3, 200
Inclusive Production Cross Sections from 920 GeV Fixed Target Proton-Nucleus Collisions
Inclusive differential cross sections and
for the production of \kzeros, \lambdazero, and
\antilambda particles are measured at HERA in proton-induced reactions on C,
Al, Ti, and W targets. The incident beam energy is 920 GeV, corresponding to
GeV in the proton-nucleon system. The ratios of differential
cross sections \rklpa and \rllpa are measured to be and , respectively, for \xf . No significant dependence upon the
target material is observed. Within errors, the slopes of the transverse
momentum distributions also show no significant
dependence upon the target material. The dependence of the extrapolated total
cross sections on the atomic mass of the target material is
discussed, and the deduced cross sections per nucleon are
compared with results obtained at other energies.Comment: 17 pages, 7 figures, 5 table
Measurement of the J/Psi Production Cross Section in 920 GeV/c Fixed-Target Proton-Nucleus Interactions
The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production
cross sections of J/Psi mesons are measured in proton-nucleus interactions.
Data collected by the HERA-B experiment in interactions of 920 GeV/c protons
with carbon, titanium and tungsten targets are used for this analysis. The
J/Psi mesons are reconstructed by their decay into lepton pairs. The total
production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46
nb/nucleon. In addition, our result is compared with previous measurements
Search for the Flavor-Changing Neutral Current Decay with the HERA-B Detector
We report on a search for the flavor-changing neutral current decay using events recorded with a dimuon trigger in
interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find
no evidence for such decays and set a 90% confidence level upper limit on the
branching fraction .Comment: 17 pages, 4 figures (of which 1 double), paper to be submitted to
Physics Letters
- …