Radar detection of the nucleus and coma of comet hyakutake

Radar observations of comet Hyakutake (C/1996 B2) made at the Goldstone Deep Space Communications Complex in California have detected echoes from the nucleus and from large grains in the inner coma. The nucleus of this bright comet was estimated to be only 2 to 3 kilometers in diameter. Models of the coma echo indicate backscatter from porous, centimeter-size grains ejected anisotropically at velocities of tens of meters per second. The radar observations suggest that a comet's activity may be a poor indicator of its size and provide evidence that large grains constitute an important component of the mass loss from a typical active comet.     

Land-use allocation protects the Peruvian Amazon

Disturbance and deforestation have profound ecological and socioeconomic effects on tropical forests, but their diffuse patterns are difficult to detect and quantify at regional scales. We expanded the Carnegie forest damage detection system to show that, between 1999 and 2005, disturbance and deforestation rates throughout the Peruvian Amazon averaged 632 square kilometers per year and 645 square kilometers per year, respectively. However, only 1 to 2% occurred within natural protected areas, indigenous territories contained only 11% of the forest disturbances and 9% of the deforestation, and recent forest concessions effectively protected against clear-cutting. Although the region shows recent increases in disturbance and deforestation rates and leakage into forests surrounding concession areas, land-use policy and remoteness are serving to protect the Peruvian Amazon.     

Separation and purification of anthocyanins by high-speed countercurrent chromatography and screening for antioxidant activity

The all-liquid chromatographic technique of high-speed countercurrent chromatography (HSCCC) has been applied for separations of anthocyanins. The biphasic mixture of tert-butyl methyl ether/n-butanol/acetonitrile/water (2:2:1:5) acidified with trifluoroacetic acid was found to be a suitable solvent system for anthocyanin separation. In some cases, enrichment of the pigments on Amberlite XAD-7 resin prior to HSCCC has been carried out. The anthocyanin mixtures from red cabbage, black currant, black chokeberry, and roselle were successfully fractionated using HSCCC. Peak purity control was done by nuclear magnetic resonance spectroscopy as well as electrospray ionization ion trap multiple mass spectrometry. Finally, antioxidant activity of the purified pigments was determined using the Trolox equivalent antioxidant capacity test.     

Recurrent Mass Selection for Reduced Seed Dormancy in Cuphea lanceolata and Cuphea laminuligera

Seed dormancy is a domestication barrier in certain Cuphea species. Between and within species variation has been observed for seed dormancy in agronomically promising Cuphea species, e.g., C. laminuligera Koehne and C lanceolata Ait. In tins note, we report on progress made in reducing seed dormancy through recurrent mass selection in the C. lanceolata population LN43 and LN78. The germination percentages of unselected LA12 and LN43 populations increased from 0.0 % to greater than 95.0 % following an after-ripening period of 20 weeks. We observed no germination percentage differences between unselected and selected LN43 populations following two cycles of selection. In contrast, there were highly significant differences between the unselected and selected populations of LA12 following two cycles of selection. The germination percentages of cycle zero (C₀) and cycle two (C₂) populations after-ripened 10 weeks were 10.7 and 92.7 %, respectively. After one cycle of selection in the C. Lanceolata population LN78, the germination percentage of seed after-ripened 10 weeks had increased from 1.3 % for the C_o population to 28.7 % for the C₀ population. In summary, mass selection greatly reduced seed dormancy in LA12 and LN78, but had no effect in LN43.     

Microbial respiration and growth during the decomposition of wheat straw

The effect of N on the disappearance of C from 1.5 g wheat (Triticum aestivum L. var. “Nugaines”) straw decomposing in sand and the response of the biomass to addition of N (adequate to bring the C:N ratio to 48:1) and C (200 mg of glucose-C) were determined. A concept was used that assumed the change in the microbial biomass was proportional to the change in acid hydrolyzable amino acid-N. Microbial respiration (CO₂ evolution and O₂ uptake) and growth were stimulated by the initial addition of N (which brought the original C:N ratio from 150:1 to 48:1), but the addition of the same amount of N to the system at 240 h that had received no N initially resulted in slight if any increase in respiration or microbial growth. The response of the microflora to the 200 mg of glucose-C additions after 240 h indicated the microbial populations were primarily limited by available C rather than available N after only 240 h incubation, even though about 95% of the original straw residue-C plus biomass C remained in the system. Respiratory quotients indicated a qualitative shift over time in the average oxidation state of the substrates being metabolized. It is postulated that the RQ shift resulted, at least in part, from death of the population rather than totally from the availability of the straw substrate.The initial addition of N resulted in 3.8 times the net amino acid production, but only 1.6 times the CO₂-C production over 240 h compared with the control without added N. These results suggest that N availability might result in a change in the growth yield of the microbial population.     

Carryover of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from soil to plant and distribution to the different plant compartments studied in cultures of carrots (Daucus carota ssp. Sativus), potatoes (Solanum tuberosum), and cucumbers (Cucumis Sativus)

A vegetation study was carried out to investigate the carryover of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) from soil mixed with contaminated sewage sludge to potato, carrot, and cucumber plants. Analysis was done by liquid-extraction using acetonitrile with dispersive SPE cleanup and subsequent HPLC-MS/MS. In order to assess the transfer potential from soil, transfer factors (TF) were calculated for the different plant compartments: TF = [PFC](plant (wet substance))/[PFC](soil (dry weight)). The highest TF were found for the vegetative plant compartments with average values for PFOS below those for PFOA: cucumber, 0.17 (PFOS), 0.88 (PFOA); potato, 0.36 (PFOS), 0.40 (PFOA); carrot, 0.38 (PFOS), 0.53 (PFOA). Transfer of PFOA and PFOS into potato peelings (average values of TF: PFOA 0.03, PFOS 0.04) exceeded the carryover to the peeled tubers (PFOA 0.01, PFOS < 0.01). In carrots, this difference did not occur (average values of TF: PFOA 0.04, PFOS 0.04). Transfer of PFOS into the unpeeled cucumbers was low and comparable to that of peeled potatoes (TF < 0.01). For PFOA, it was higher (TF: 0.03).