Factors affecting formation of methyl nitrite in soils

The formation of CH₃ONO in 11 soils treated with HNO₂ or NaNO₂ in a closed system, was studied by measuring the concentration in the gas space above the soil and by absorbing CH₃ONO in HI. The gaseous concentration of CH₃ONO increased and then decreased following additions of HNO₂ or NaNO₂, and the production of CH₃ONO increased with increasing concentrations of HNO₂ or NaNO₂ added to soils.
The amounts of CH₃ONO trapped in HI were 13.5 to 20.4 times higher than those determined by integrating under the net production curves. The evolved CH₃ONO amounted to 0.4 to 3.5% of added NO₂⁻, and 4.2 to 50% of the gaseous forms of N absorbed by acidic KMnO₄ solution. The CH₃ONO evolved from soils was positively correlated with the methoxy content of the soils, and inversely related to soil pH, with negligible amounts being evolved from alkaline soils. The results show that CH₃ONO is a product of NO₂⁻ decomposition in soils, and indicate that small concentrations of the gas may be produced in N–fertilized soils in which NO₂⁻ accumulates.     

Analgesic and antidiarrheal properties of Ocimum selloi essential oil in mice

Ocimum selloi essential oil (2, 20, and 200 mg/kg; p.o.) reduced, in a dose-dependent way, the abdominal contraction induced by acetic acid (0.6%; i.p.) and the diarrhea episodes induced by castor oil in mice. At the higher dose (200 mg/kg; p.o.), the essential oil significantly reduced intestinal transit (P<0.05) in the charcoal meal test. The main component detected in O. selloi essential oil was methyl chavicol (98%; GC and GC/MS).These effects seems to support the use of O. selloi against diarrhea, intestinal spasm and visceral pain.     

Responsiveness to Progestagen-eCG-Cloprostenol Treatment in Goat Food Restricted for Long Period and Refed

For 6 months, 10 adult Saanen crossbred goats were fed undernutrition diet (70% maintenance), and finally five goats were refed for 6 weeks with 150% maintenance. In all animals oestrus was synchronized using 45 mg FGA vaginal sponge for 11 days, 300 IU eCG and 50 microg cloprostenol 48 h prior to sponge removal. From oestrus onset, during a 24-h period, blood samples were collected for oestradiol and NEFA assay. Ovulation was verified by laparoscopy 3 days after sponge removal. Body mass loss was 18.62 +/- 3.03% of initial weight and in refed goats body weight recovery was 90.63 +/- 3.56%. NEFA level was higher in restricted goats (p < 0.05). Fifty per cent of underfed goats (2/4) and all refed goats (4/4) exhibited oestrus and ovulation. Significant relationship (p < 0.05) was found between weight loss and the interval sponge removal-oestrus onset (r = 0.91) or ovulation rate (r = 0.70). Only in the refed group was the ovulation rate related to the oestradiol amount (r = 0.99) (p < 0.05). Collectively results showed that a short period of improved feeding re-established the responsiveness of oestrus synchronization in chronically fasted goats.     

Mesoscale physical processes and the distribution and composition of ichthyoplankton on the southern Brazilian shelf break

The southern Brazilian shelf supports the largest fish stocks in the country, and studies on physical–biological processes in the ecology of ichthyoplankton have been recommended to provide a better understanding of the variability of the recruitment of fishing resources. This study is the first to examine the influence of mesoscale physical processes on the distribution of early life stages of fish in this shelf‐break region. Collections of fish eggs and larvae and measurements of temperature and salinity were made at 13 stations along cross‐shelf transects in December 1997. Myctophidae, Bregmacerotidae, Clupeidae, Synodontidae and Engraulidae were the most abundant larvae in the northern region, while Engraulidae and Bregmacerotidae prevailed further south. In situ hydrographic data, NOAA/AVHRR images and merged TOPEX/POSEIDON + ERS‐1/2 satellite altimetry taken during the cruise revealed an anticyclonic eddy dominating the shelf around 31°S. Larval fish abundance was lower at the centre of this feature, suggesting that the eddy advected poorer offshore waters of tropical origin towards the inner shelf‐concentrating the larvae around the eddy.     

Combinatorial electrochemistry: A highly parallel, optical screening method for discovery of better electrocatalysts

Combinatorial screening of electrochemical catalysts by current-voltage methods can be unwieldy for large sample sizes. By converting the ions generated in an electrochemical half-cell reaction to a fluorescence signal, the most active compositions in a large electrode array have been identified. A fluorescent acid-base indicator was used to image high concentrations of hydrogen ions, which were generated in the electrooxidation of methanol. A 645-member electrode array containing five elements (platinum, ruthenium, osmium, iridium, and rhodium), 80 binary, 280 ternary, and 280 quaternary combinations was screened to identify the most active regions of phase space. Subsequent "zoom" screens pinpointed several very active compositions, some in ternary and quaternary regions that were bounded by rather inactive binaries. The best catalyst, platinum(44)/ruthenium(41)/osmium(10)/iridium(5) (numbers in parentheses are atomic percent), was significantly more active than platinum(50)/ruthenium(50) in a direct methanol fuel cell operating at 60 degreesC, even though the latter catalyst had about twice the surface area of the former.     

Amino acid availability and protein digestibility of several protein sources for Nile tilapia,Oreochromis niloticus

Apparent amino acid availability coefficients and protein digestibility of four animal products [fish meal (FM), meat and bone meal (MBM), poultry by‐product and feather meal] and four plant protein‐rich products [soybean meal (SBM), cottonseed meal‐28, cottonseed meal‐38 and corn gluten meal (CGM)] were determined for Nile tilapia, Oreochromis niloticus. Ingredients were incorporated to a practical reference diet at a 7 : 3 ratio (70% of reference diet and 30% of test ingredient). Chromic oxide was used as external digestibility marker. Among animal products poultry by‐product meal (PBM; 89.7%) and FM (88.6%) presented the highest apparent protein digestibility (APD) while MBM (78.4%) and feather meal (78.5%) presented the lowest APD. Among plant protein‐rich products CGM (91.4%) and SBM (92.4%) presented the highest APD values while cottonseed meal‐28 presented the lowest APD (78.6%). Average apparent amino acid availability of feed ingredients was similar to protein digestibility with 92.3%, 89.6%, 73.4%, 80.7%, 88.9%, 84.4%, 91.2% and 79.7% values for SBM, CGM, cottonseed meal‐28 and 38, FM, MBM, PBM and feather meal respectively. These results indicate that O. niloticus is able to utilize efficiently different feedstuffs.