Initial growth and survival of Eucalyptus spp. and Mimosa caesalpiniifolia Benth. in silvopastoral systems and their impact on herbage accumulation of Urochloa decumbens Stapf R. D. Webster

Agroforestry Systems - Silvopastoral systems (SPS) combine tree, herbaceous, and animal components, and may contribute to improve productivity and diversification of activities over time. This...     

Alcohol self-administration disrupts reproductive function in female macaque monkeys

Female macaque monkeys self-administered high doses of alcohol (2.9 to 4.4 grams per kilogram per day) for 3 to 6 1/2 months. Amenorrhea, atrophy of the uterus, decreased ovarian mass, and significant depression of luteinizing hormone levels were associated with chronic alcohol intoxication. Reproductive system failure in female primates following self-induced dependence on alcohol parallels the results of clinical studies of alcoholic women.     

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.     

Assessing the use of erosion modeling to support payment for environmental services programs

Purpose

Payment for environmental services (PES) has assumed increasing importance in discussions about sustainable development strategies. Many of the PES programs are based on water erosion control and the corresponding environmental and economic benefits generated in the basins where they are implemented. The main objective of this study was to show how erosion susceptibility models can support PES programs.

Materials and methods

The application of the Universal Soil Loss Equation (USLE) in the Sarandi Experimental River Basin (32.7 km²), located in the Federal District, Brazil, was used as a study case. Then a scheme for organizing knowledge about ecosystem services related to erosion control and water resources was performed. Considering the generated scheme, the USLE results, the land use map, and the water use in the region, we evaluated how erosion modeling could support PES programs.

Results and discussion

The results show that a large part of the study basin (90%) presents “low” susceptibility to erosion, which is significant in terms of the use and conservation of ecosystem services, as well as being a limitation regarding the need for the implantation of PES programs for erosion control. Incentives for maintaining the natural vegetation in areas with higher erosion susceptibility have the greatest potential to justify PES programs in the study basin, and the sanitation company is the potential payer for erosion control in the Sarandi River Basin.

Conclusions

The application of the USLE in a spatially distributed form proved to be an important support tool for land management and the implementation of PES policies.     

Antinociceptive effect of Hyptis pectinata leaves extracts

Oral administration of hexanes, chloroform, and ethyl acetate extracts of the leaves of Hyptis pectinata significantly reduced the number of writhing induced by acetic acid and increased the response to thermal stimuli in hot-plate test. Such effect was completely reversed by the opioid antagonist naloxone.     

Accompanying ions of ammonium sources and nitrate : ammonium ratios in tomato plants

The tomato (Solanum lycopersicum L.) cultivar Micro‐Tom (MT) is widely used in physiological studies, but the effects of nitrate ( ) and ammonium ( ) ratios ( : ratios) and, in particular, the effects of the accompanying ions in sources are unknown. To determine whether the accompanying ions in sources influence toxicity, the effects of : ratios on the physiology, electrolyte leakage index, nutrition, and dry weight were studied using hydroponics. The sources were ammonium chloride (NH₄Cl) or ammonium sulfate [(NH₄)₂SO₄], and five : ratios were used: 100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100. The source was calcium nitrate [Ca(NO₃)₂], and the nitrogen (N) concentration was 15 mmol L^?1. The results indicate that NH₄Cl or (NH₄)₂SO₄ can be used in studies on toxicity because the accompanying ions did not influence the tomato plants. In addition, : ratios of 100 : 0 and 75 : 25 resulted in the highest dry weight of tomato plants, whereas ratios of 25 : 75 or 0 : 100 were toxic.     

Growth of juvenile common snook (Centropomus undecimalis Bloch, 1792) reared at different temperatures and salinities: Morphometric parameters,RNA/DNA,and protein/DNA ratios

We investigated the growth of juvenile common snook (Centropomus undecimalis) reared at 25°C and 28°C and salinities of 0.3, 15, and 32 g L^?1. Total length, weight, RNA/DNA, and protein/DNA ratios were determined after 90 days of experiment. Higher growth was observed at 28ºC compared with 25°C, at the same salinity. At 28°C and 15 g L^?1 salinity, the weight (25.14 g) of juveniles was twice that of the juveniles reared at the lower temperature. At different salinities, only higher temperature affected growth, with higher weight values obtained at 15 g L^?1 in comparison with 0.3 and 32 g L^?1. Length was similar at 0.3 and 15 g L^?1. The RNA/DNA ratio was greater in juveniles reared at a salinity of 15 g L^?1 when compared with 0.3 and 32 g L^?1. This study shows that the combination of higher temperature and intermediate salinity promotes better growth of common snook juveniles.     

Two epizootic Perkinsus spp. events in commercial oyster farms at Santa Catarina,Brazil

Perkinsus spp. have been detected in various bivalve species from north‐east Brazil. Santa Catarina is a South Brasil state with the highest national oyster production. Considering the pathogenicity of some Perkinsus spp., a study was carried out to survey perkinsosis in two oyster species cultured in this State, the mangrove oyster Crassostrea gasar and the Pacific oyster Crassostrea gigas. Sampling involved eight sites along the state coast, and oyster sampling was collected during the period between January 2013 and December 2014. For the detection of Perkinsus, Ray's fluid thioglycollate medium (RFTM) and histology were used, and for the identification of the species, PCR and DNA sequencing were used. Perkinsus spp. was found by RFTM in C. gigas and C. gasar from São Francisco do Sul. This pathology was also detected in C. gasar from Balneário Barra do Sul both, by RFTM and histology. Perkinsus marinus was identified in C. gigas and C. gasar from São Francisco do Sul and Perkinsus beihaiensis in C. gasar from Balneário Barra do Sul. This is the first report of P. marinus in C. gigas from South America. Results of this preliminary study suggest that both oyster species tolerate the species of Perkinsus identified, without suffering heavy lesions.