Reconstruction of Current Flow and Imaging of Current-Limiting Defects in Polycrystalline Superconducting Films

Magneto-optical imaging was used to visualize the inhomogeneous penetration of magnetic flux into polycrystalline TlBa2Ca2Cu3Ox films with high critical current densities, to reconstruct the local two-dimensional supercurrent flow patterns and to correlate inhomogeneities in this flow with the local crystallographic misorientation. The films have almost perfect c-axis alignment and considerable local a- and b-axis texture because the grains tend to form colonies with only slightly misaligned a and b axes. Current flows freely over these low-angle grain boundaries but is strongly reduced at intermittent colony boundaries of high misorientation. The local (<10-micrometer scale) critical current density Jc varies widely, being up to 10 times as great as the transport Jc (scale of approximately 1 millimeter), which itself varies by a factor of about 5 in different sections of the film. The combined experiments show that the magnitude of the transport Jc is largely determined by a few high-angle boundaries.     

Sequential extraction methods for soil organic nitrogen

(pp. 825–831)
This study was carried out to clarify the effects of soil nitrate before cultivation and amounts of basal-dressed nitrogen on additional N application rate and yields of semi-forced tomato for three years from 1998 to 2000. The amounts and timing of additional N dressing were determined based on diagnosis of petiole sap nitrate. The top-dressing was carried out with a liquid fertilizer when the nitrate concentration of a leaflet's petiole sap of leaf beneath fruit which is 2–4 cm declined below 2000 mg L⁻¹.
For standard yield by the method of fertilizer application based on this condition, no basal-dressed nitrogen was required when soil nitrate before cultivation was 150 mg kg⁻¹ dry soil or higher in the 0–30 cm layer; 38 kg ha⁻¹ of basal-dressed nitrogen, which corresponds to 25% of the standard rate of fertilizer application of Chiba Prefecture, was optimum when soil nitrate before cultivation was 100150 mg kg⁻¹ dry soil; 75 kg ha⁻¹ of basal-dressed nitrogen, which corresponds to 50% of the standard, was optimum when soil nitrate before cultivation was under 100 mg kg⁻¹ dry soil. A standard yield was secured and the rate of nitrogen fertilizer application decreased by 49–76% of the standard by keeping the nitrate concentration of tomato petiole sap between 1000–2000 mg L⁻¹ from early harvest time to topping time under these conditions.     

Introduction into Italy of Gryon pennsylvanicum (Ashmead), an egg parasitoid of the alien invasive bug Leptoglossus occidentalis Heidemann

Leptoglossus occidentalis (Heteroptera, Coreidae), a Nearctic species, was accidentally introduced into Northern Italy in the late 1990s, from where it has spread throughout Europe. The bug causes abortion of immature cones of Pinus pinea L., with economic impact on the pine‐nut industry. As part of a pest control research program, the egg parasitoid Gryon pennsylvanicum Ashmead (Hymenoptera, Platygastridae) was collected from British Columbia, Canada, and legally introduced to a quarantine climatic chamber in Florence, Italy. The egg parasitoid will be tested against native non‐target heteropterans, an environmental impact assessment will be conducted, and a mass rearing method will be developed if appropriate. The ultimate goal is to release G. pennsylvanicum into Italian P. pinea forests for classical biological control of L. occidentalis.     

Suppression of nematodes in a coastal grassland soil

The nematophagous fungi Arthrobotrys oligospora and Myzocytiopsis glutinospora increase to large numbers (>10³ propagules/g of soil) when moth larvae killed by entomopathogenic nematodes are added to soil microcosms. In spite of these increases, it is unclear how effective these nematophagous fungi are in suppressing nematodes. We measured nematode mortality in microcosms with small numbers of assay nematodes, and we examined assay nematodes recovered at the end of the experiment for signs of fungal parasites. Because the microcosms did not have a moat or other refuge, the assay nematodes remained vulnerable for the 3 days that they were in the soil. Mortality in this experiment was not substantially increased compared to a previous experiment, which measured the mortality of a larger number of assay nematodes in microcosms surrounded by a moat. Mortality, however, increased from 34 to 50% when recovered assay nematodes were examined and when those with conidia of the nematophagous fungus Hirsutella rhossiliensis were considered dead. The zoosporic fungus M. glutinospora was not detected, perhaps because the soil water potential was too low. Contrary to our expectations, there was no evidence of negative feedback on nematodes (i.e., no evidence of density-dependent mortality) because the addition of dead moth larvae greatly increased numbers of resident nematodes and A. oligospora but did not greatly affect the probability of nematode mortality.     

In this issue – August 2011

History of veterinary education in Australia · Neurological diseases following bacterial and protozoal infections · Lameness model in sheep · Effects of barefoot trimming · EGFR and HER‐2 as prognostic makers in mammary tumours · Bacteria in semen fractions in dogs     

In this issue – April 2011

Lomustine‐associated toxicity · Iliopsoas fibrotic myopathy · Porcine circovirus‐associated disease in weaner pigs · Measures of welfare in Bos indicus heifers · eFSH for superovulation in mares · Recurrent Actinobacillus peritonitis in a horse