Macroscopic, neat, single-walled carbon nanotube fibers

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties.     

Three-year growth responses of Pinus taeda L. to simulated rain chemistry,soil magnesium status,and ozone

Height, diameter, and biomass were measured for loblolly pine (Pinus taeda L) seedlings grown in soil containing 15 or 35 Μg Mg g^?1 and exposed from May to October in 1987, 1988, and 1989 to three O₃ concentrations (sub-ambient, ambient, or twice-ambient) and to rain pH levels of 3.8 or 5.2. Reduction in biomass accumulation in seedlings exposed to twice-ambient O₃ vs sub-ambient O₃ was 14% (P = 0.03) in 1987, 11.4% (P = 0.002) by 1988, and 8% (P = 0.15) by 1989. The greatest height growth occurred in seedlings exposed to twice-ambient O₃, and the greatest stem diameter growth occurred in seedlings exposed to sub-ambient O₃. A comparison of stem volume (d²h) with stem biomass suggested that tissue density was reduced by elevated O₃. Biomass accumulation response to rainfall chemistry was small (5.5% reduction in the low pH treatment in 1989) and not statistically significant for most plant tissues. Growth response to soil Mg status was not significant. Hoewever, in 1989 treatment interactions between rainfall chemistry and soil Mg status were observed. Height was 5% greater (P = 0.02) and biomass was 6% greater (P = 0.10) in seedlings grown in higher-Mg soil and receiving higher-pH rainfall than seedlings grown in any of the other pH-Mg treatment combinations. The data suggest direct adverse effects of near ambient O₃ and indirect, slower acting and interacting adverse effects of rainfall chemistry and soil nutrient status on growth of loblolly pine.     

IHHN Virus as an Etiological Factor in Runt-Deformity Syndrome (RDS) of Juvenile Penaeus vannamei Cultured in Hawaii

Runtdeformity syndrome (RDS) is an economically significant, frequent disease problem of cultured Penaeus vannamei . RDS is characterized by variable, often greatly reduced, growth rate of up to 30% of a cultured population and many shrimp with cuticle deformities of the rostrum, anterior appendages or other parts. The cause of RDS is undetermined.
Nursery trials comparing histologically IHHN-positive and histologically IHHN-negative Penaeus vannamei cultured under identical conditions were conducted at The Oceanic Institute. The IHHN-positive populations developed RDS symptoms including increased individual size variation, reduced population growth, and high prevalance of rostrum, antennae or cuticle deformity, while the IHHN-negative groups displayed none of these symptoms. No other diseases or parasites were identified in the IHHN-positive populations that would account for the RDS symptoms.
A single commercialele nursery was stocked with histologidly IHHN-positive P. vannamei and a high prevalence of RDS was observed. Shrimp growth was bimodal with a subpopulation growing normally and a subpopulation growing slowly. Significant relationships between shrimp harvest size and IHHN prevalance, selected individual organ IHHN severity grades and IHHN severity index (six organs evaluated) were found. Large, apparently normal shrimp were less severely infected with virus and did not display any cuticle deformities.
In sum, these data provide epidemiological and histopathological evidence for the hypothesis that infection by IHHN virus is the cause of RDS in cultured P. vannamei .     

Effect of soil application of cadmium contaminated lime on soil cadmium distribution and cadmium concentration in strawberry leaves and fruit

Heavy metal environmental pollution which occurs as a result of lime contaminated with cadmium (Cd) poses a potential health hazard. This investigation was undertaken to study uptake of Cd by strawberry plants grown in soil amended with three different sources and two different rates of industry waste lime containing 3.4, 14.3, and 60.0 mg Cd/kg, respectively. The effects of Cd applied to the soil were investigated, including its distribution in the soil and effect on Cd concentration in strawberry cv. Senga Sengana (Fragaria anassa) leaves and fruit in response to soil organic matter content and lime rates. Cadmium accumulated mainly in the plough layer, increasing from 0.170 mg Cd/kg (background level) to a maximum of 1.2 mg Cd/kg. Fruit had very high, hazardous Cd concentrations regardless of its content in the soil. This indicates that Cd was easily taken up by strawberry plants and accumulated in upper plant parts, including the fruit. Soil Cd content had no effect on concentration of this element in strawberry fruit. However, plant Cd uptake and fruit concentration was increased in acid soils even when soil Cd concentration was low.     

Assignment testing reveals multiple introduced source populations including potential ash hybrids (Fraxinus excelsior × F. angustifolia) in Ireland

Large-scale reforestation programmes are a major source of unwarranted gene flow and can have profound consequences on local genetic diversity. Recently, ash has been introduced to Ireland from continental Europe to stock plantations but has often exhibited poor stem form. It was not known whether these trees were Fraxinus excelsior, Fraxinus angustifolia or interspecific hybrids that are known to occur in continental Europe. F. excelsior is the only native ash in Ireland, so the introduced populations represent a potential threat for the genetic diversity of native populations. We characterized the introduced trees within two plantations (Clonee and Kildalkey) using morphological characters and six microsatellite markers. Samples from continental Europe were included for comparison. Plantations exhibited higher genetic diversity than control populations because our data suggest they contain a mixture of several provenances. There was a small but significant differentiation between plantations and control populations (Ф_CT = 0.0211). Bayesian analysis to infer population structure and to assign introduced individuals to reference populations clearly demonstrated the presence of hybrid individuals within the plantations. The percentage of trees detected with potential hybrid origin ranged from 28 to 58 % depending on the plantation and the threshold data analysis level chosen. Most hybrids could be considered cryptic because there was a lack of intermediate morphology for hybrid individuals that mainly clustered with F. excelsior. The results indicated that the source of material at the two plantation sites differed. Management options to minimize the impact of these introduced populations are discussed.