Diets of the demersal fishes on the shelf off Iwate,northern Japan

Diets of demersal fishes were determined on the shelf (ca. 130 m deep) off Iwate, Japan. Samples were taken in three different types of habitat, an artificial reef (AR) site, a natural reef (NR) site, and sandymud bottom (SB) site, from May 1987 to September 1991, mostly every two months. A total of 67 prey items were recognized in the stomachs of 45 predator fish species. The most important preys were the pelagic fishes Sardinops melanostictus and Engraulis japonicus, which comprised 37% wet wt of the overall stomach contents. The percentage of pelagic fishes was highest at AR site, where fish density was highest. The dominant ten species could be divided into five feeding types. The pelagic fish feeders Physiculus maximowiczi and Gadus macrocephalus fed mainly on S. melanostictus. The dietary breadth of P. maximowiczi was wide, while that of Gadus macrocephalus was narrow. The pelagic crustacean feeder Theragra chalcogramma mostly consumed Themisto japonica and euphausiids and showed the least dietary overlap with other fishes. Benthic fish feeders were Hemitripterus villosus and Liparis tanakai. The benthic crustacean feeders Alcichthys alcicornis and Hexagrammos otakii consumed benthic crustaceans as well as pelagic and benthic fishes and showed the largest dietary breadth. The benthic invertebrate feeders Gymnocanthus intermedius, Dexistes rikuzenius and Tanakius kitaharai fed mainly on polychaetes and benthic crustaceans. But Gymnocanthus intermedius consumed a significant proportion of pelagic fishes. Ontogenetic dietary shift was recognized for these fishes. Pelagic fishes were consumed more intensively by larger individuals, especially true of A. alcicornis, Theragra chalcogramma and Gadus macrocephalus. Predominancy of the two most adundant species, P. maximowiczi and A. alcicornis, may be supported by their wide dietary breadth and the significant proportion of pelagic fish in their diets. Interspecific dietary overlap was low in most cases suggesting that food resources were well partitioned, although some high overlap was observed among the pelagic fish feeders, A. alcicornis, and Gymnocanthus intermedius, and among the benthic invertebrate feeders. Interspecific competition seemed more likely in the benthic invertebrate feeders than in the pelagic fish feeders partly because of superabundance of the pelagic prey S. melanostictus.     

Phylloplane algae of standing dead Spartina alterniflora

Phylloplane (leaf surface) algae on leaves from standing dead Spartina alterniflora Loisel in Sapelo Island marshes were enumerated by epifluorescence microscopy. The green alga Pseudendoclonium submarinum Wille dominated algal biovolume on both short-and tall-form plants during summer and winter. Intra-leaf and intra-plant patterns of algal biovolume and diversity indicated that desiccation stress may be an important selective factor. Observed epiphyte densities are 10- to 200-fold lower than values reported for communities on continuously submerged aquatic vegetation. Algal biovolume was less than 10% of that contained in the saprophytic (fungal and bacterial) community.     

The effect of ink types and printing processes on flotation deinking efficiency of wastepaper recycling

Wastepaper is the largest fraction of solid waste. Flotation deinking plays an essential role in the product quality and process cost of wastepaper recycling. This paper investigated the effect of ink types and printing processes on flotation deinking. Examination of ink types in this study revealed that newsprint oil-based offset-cold and offset-heat inks contain substantial oil (45 to 60%) and resin (5 to 35%); water-based ink contains water (40%) and resin (polystyrene, 30%); and these inks are liquids with densities around 1 g/cm³ at 25 °C. On the other hand, photocopy and laser-print toners were found to be solid powders with particle diameters of about 20 μm, densities of 1 to 1.5 g/cm³, and a composition that consists primarily of styrene-acrylate copolymers (60 to 90%). Except for water-based ink, which is water soluble, all inks in their initial state are hydrophobic. It was found that for newsprint oil based offset-cold inks there is little change in their surface chemical properties, and their hydrophobic character is retained. These inks in the newsprint wastepaper pulp can be effectively removed by flotation. On the other hand, it was found that during the printing processes, the toner particles undergo polymerization (fusion) and oxidation with the subsequent formation of peroxide bonds due to exposure to heat, light, and oxygen (air). The fusion due to polymerization causes bonding to the paper fibers and the creation of larger toner particle sizes. The oxidation creates a greater polarity at the toner particle surface. These effects account for the poor efficiency in the flotation deinking of office waste. In order to improve office wastepaper recycling, it is evident, based on this study and policy considerations, that there is a need to find ways of improving the efficiency and effectiveness of flotation deinking by modification of the surface properties of printed toner particles, or designing new toner particles.     

北极苔原和森林地区的稳定性及脆弱性与社会和环境变化

北极苔原带和北方森林(北部地区)因其分布广阔并远离农业土地利用变化及工业发展的影响,而一度被认为是地球上最后的净土.但如今这些地区如同地球上任何别的地区一样,也正经受着环境和社会变化的影响.本文总结了北部地区在全球系统中所起的作用,并提出方案以便对导致该地区对社会和环境变化敏感的那些因子进行评价.     

Comparison of chorionic villus sampling and amniocentesis: Current status of prenatal diagnosis in Japan

Data were tabulated and compared for cases involving prenatal diagnostic procedures performed in the 8 years between January 1985 and December 1992. Of a total of 2781 pregnancies, 2546 cases (91·5 per cent) were diagnosed by amniocentesis, and 235 (8·5 per cent) by chorionic villus sampling (CVS). These findings reflect the fact that amniocentesis has taken deep root as the prenatal diagnostic procedure widely acknowledged by society, whereas even the existence of CVS has yet to be generally recognized. Analysis of our clinical and laboratory results and complication rates, however, suggests that CVS is a safe and accurate alternative to amniocentesis which should and can be positively presented to all patients who are candidates for prenatal diagnosis.     

Malachite green in synthetic medium for the isolation ofFusarium spp. from plant tissues

The Science of Nature -     

Prenatal diagnosis of a fetus with partial monosomy 7(q34→qter) and partial trisomy 18(q21→qter)

Ultrasound examination of a 31-year-old woman at 27 weeks' gestation revealed fetal growth retardation, a bilateral cleft lip and palate, and the absence of median cerebral structures. Chromosome analysis after cordocentesis showed an abnormal karyotype with a structural abnormality of the long arm of chromosome 7: 46,XX,—7,+der(7), t(7;18) (q34;q21.3)mat. The pregnancy was terminated at week 29. The ultrasound findings were confirmed by post-mortem examination, which also revealed a semilobar holoprosencephaly.