GONG Observations of Solar Surface Flows

Doppler velocity observations obtained by the Global Oscillation Network Group (GONG) instruments directly measure the nearly steady flows in the solar photosphere. The sun's differential rotation is accurately determined from single observations. The rotation profile with respect to latitude agrees well with previous measures, but it also shows a slight north-south asymmetry. Rotation profiles averaged over 27-day rotations of the sun reveal the torsional oscillation signal-weak, jetlike features, with amplitudes of 5 meters per second, that are associated with the sunspot latitude activity belts. A meridional circulation with a poleward flow of about 20 meters per second is also evident. Several characteristics of the surface flows suggest the presence of large convection cells.     

Single-Electron Transport in Ropes of Carbon Nanotubes

The electrical properties of individual bundles, or "ropes," of single-walled carbon nanotubes have been measured. Below about 10 kelvin, the low-bias conductance was suppressed for voltages less than a few millivolts. In addition, dramatic peaks were observed in the conductance as a function of a gate voltage that modulated the number of electrons in the rope. These results are interpreted in terms of single-electron charging and resonant tunneling through the quantized energy levels of the nanotubes composing the rope.     

True potato seed research and development in Vietnam

Quality tuber planting material is unavailable in the Red River Delta (RRD). The use of True Potato Seed (TPS) was considered as an alternative planting material. During the 1985–86 and 1986–87 seasons, 21 and 40 kilos of open pollinated TPS, respectively, were collected in the southern highlands and distributed to over 40 cooperative groups of farmers in the RRD. Fifty-two hectares (1985-86) and 120 hectares (1986-87) of potatoes were produced from transplants in the two years of on-farm production. Approximately 50% of the farmers were successful in both years. Lack of experience and too wet or too dry growing conditions caused most of the failures. Yields from transplants ranged from 5 to 13 t/ha with 150 to 300 seedling tubers/m². Seedling tubers can be stored for eight months with low storage losses and when replanted give substantially higher yields than those obtained from locally grown, degenerated seed tubers.     

A Review of Probiotics in Shrimp Aquaculture

Development of shrimp aquaculture has been associated with increases in infectious diseases and environmental degradation. An effective alternative to chemicals and antibiotics used for the prevention of these problems is to administer probiotics into the rearing system. Three bacterial genera, Bacillus, Vibrio, and Pseudomonas, are commonly administered as probiotics in shrimp aquaculture. Candidate probiotics are species specific and need to be tested for their effectiveness for certain species in in vitro and in vivo. Supplementation into feed is more effective in conveying probiotics into animals compared to direct application into rearing systems. Overdosage or prolonged administration of probiotics can induce immunosuppression. A cell-density of 10⁵ colony-forming units (CFU) per ml is widely recommended. A combination of probiotics results in better outcomes for the host than individual probiotics. Probiotics improve water quality while reducing pathogenic bacteria. Probiotics show positive effects through an improvement in the physiological and immune responses of shrimps. Probiotics are increasingly becoming important and more common in any organic shrimp farming.     

Effects of probiotics (Pseudomonas synxantha and Pseudomonas aeruginosa) on the growth, survival and immune parameters of juvenile western king prawns (Penaeus latisulcatus Kishinouye, 1896)

The effects of two selected probiotics ( Pseudomonas synxantha and Pseudomonas aeruginosa ) on the specific growth rate (SGR), survival and immune parameters of juvenile western king prawns ( Penaeus latisulcatus ) were examined for 84 days. Pseudomonas synxantha and P. aeruginosa were either applied into the rearing medium or supplemented in the formulated feed at a concentration of 10⁵ colony forming unit (CFU) mL⁻¹ for each probiotic. The results showed that applications of the probiotics resulted in no significant difference ( P >0.05) in the SGR and survival of the prawns, but significantly decreased the food conversion ratios ( P <0.05) compared with the control where no probiotics were applied. The supplement of the probiotics with the formulated feed enhanced the probiotic numbers in the intestines of the prawns and low bacteria numbers in the haemolymph. The prawns were significantly ( P <0.05) healthier, as indicated by the immune response obtained when both probiotics were given in combination compared with when individual probiotics were used. When applied singly, P. aeruginosa resulted in a higher health status of the prawns compared with P. synxantha . Overall, equal combinations (10⁵ CFU mL⁻¹) and volumes of P. synxantha and P. aeruginosa used as a supplement in the formulated feed resulted in an improvement in the health of the juvenile western king prawns.     

Characterization and Optimization of Culture Conditions for Aurantiochytrium sp. SC145 Isolated from Sand Cay (Son Ca) Island,Vietnam, and Antioxidative and Neuroprotective Activities of Its Polyunsaturated Fatty Acid Mixture

Aurantiochytrium is a heterotrophic marine microalga that has potential industrial applications. The main objectives of this study were to isolate an Aurantiochytrium strain from Sand Cay (Son Ca) Island, Vietnam, optimize its culture conditions, determine its nutritional composition, extract polyunsaturated fatty acids (PUFAs) in the free (FFA) and the alkyl ester (FAAE) forms, and evaluate the antioxidation and neuroprotection properties of the PUFAs. Aurantiochytrium sp. SC145 can be grown stably under laboratory conditions. Its culture conditions were optimized for a dry cell weight (DCW) of 31.18 g/L, with total lipids comprising 25.29%, proteins 7.93%, carbohydrates 15.21%, and carotenoid at 143.67 µg/L of DCW. The FAAEs and FFAs extracted from Aurantiochytrium sp. SC145 were rich in omega 3–6–9 fatty acids (40.73% and 44.00% of total fatty acids, respectively). No acute or subchronic oral toxicity was determined in mice fed with the PUFAs in FFA or FAAE forms at different doses over 90 days. Furthermore, the PUFAs in the FFA or FAAE forms and their main constituents of EPA, DHA, and ALA showed antioxidant and AChE inhibitory properties and neuroprotective activities against damage caused by H₂O₂- and amyloid-ß protein fragment 25–35 (Aβ_25-35)-induced C6 cells. These data suggest that PUFAs extracted from Aurantiochytrium sp. SC145 may be a potential therapeutic target for the treatment of neurodegenerative disorders.