Quantifying the ecosystem service of non-native weed seed predation provided by invertebrates and vertebrates in upland wheat fields converted from paddy fields

The extent of post-dispersal weed seed predation in upland wheat fields converted from paddy fields was quantified in Shizuoka Prefecture, central Japan. We investigated the temporal variability in seed predation of Italian ryegrass (Lolium multiflorum Lam.), a non-native winter annual weed in Japan, during summer after the seed shed in both the field interior areas and boundary strips, and estimated the total seed loss due to predation during the summer. Furthermore, the contribution of invertebrates and vertebrates to seed predation was estimated by using exclosures. The total seed loss due to predation during four months (from late June to late October) in the field interior areas and boundary strips was estimated to be 35–43% (the maximum proportion of seed predation per two weeks = 27%) and 42% (25%), respectively. The seed predators in the field interior areas were vertebrates (rodents or birds) and invertebrates (crickets and ground beetles). In contrast, seed predators in the boundary strips were mainly invertebrates (crickets and ground beetles). The results of this study suggest that predators make a substantial contribution in the depletion of post-dispersal seeds of Italian ryegrass in converted paddy fields.     

Integrated control of the root-knot nematode, Meloidogyne incognita, on black-pepper plantations in the amazonian region

In the Amazonian region, so-called foot-rot disease, caused by a fungus Nectria, occurs widely on black-peppers, Piper nigrum L., the roots of which are also heavily infested by the root-knot nematode, Meloidogyne incognita. Factorial experiments were conducted in this region during 1976–1978 to attempt to find out the effect of nematicide treatment, mulching with Imperata cylindrica, and non-host cover plantings, on the growth of black-peppers as well as on nematode population levels. Temic or Furadan treatment resulted in better plant growth and a reduced nematode population in the first year. Mulching resulted in exceedingly high plant growth, even though higher nematode populations were also observed. Under mulching conditions, soil temperatures at 5-cm depth seldom rose beyond 30°C throughout the year. Cover plantings of non-hosts, which had been selected by earlier inoculation tests, indicated remarkable retardation of plant growth of black-peppers, evidently due to the competition, and this also reduced the nematode population. Macroptilium atropurpureum (siratro) gave the smallest growth retardation of black-peppers. From these results, a combination of three procedures, i.e. Temic or Furadan treatment, mulching with grass straw, and cover-planting of non-hosts such as siratro, is recommended on black-pepper plantations for better plant growth and eventually better yield of black-peppers in the fields infested by root-knot nematodes.     

Microbial characteristics in anaerobic membrane bioreactor treating domestic sewage: Effects of HRT and process performance

Two anaerobic membrane bioreactors (AnMBRs) equipped with different membrane pore size (0.4 or 0.05μm) were operated at 25℃ and fed with domestic wastewater.The hydraulic retention time (HRT) of the reactors was shortened.The microbial communities of the two AnMBRs were investigated by 16S rRNA gene amplicon sequencing to see the effects of HRT.The predominant Archaea was an aceticlastic methanogen Methanosaeta.The composition of hydrogenotrophic methanogens changed with the HRTs:the population ...     

Development of a three-year-old child FE model

OBJECTIVE: Child crash dummies are conventionally used for safety performance evaluations of the child restraint system (CRS) in vehicle crash tests. To investigate injuries to various body regions of a child in detail, mathematical models are useful, and provide information that cannot be analyzed by crash dummies. Therefore, in the present research, a finite element (FE) model of a 3-year-old child has been developed by model-based scaling from the AM50 human FE model, THUMS (Total HUman body for Safety). METHODS: The dimensions of each body region were based on the anthropometry data of United States children, and material properties of child bone were estimated from data reported in the literature. Neck flexion, thorax impact responses, and torso flexion were validated against the response corridor of the 3-year-old Hybrid III dummy in calibration tests. A test of lap belt loading to the abdomen was also conducted. FE models of two different types of CRS, a 5-point harness and a tray shield CRS, were also made, and ECE R44 sled impact test simulations were conducted using the child FE model. RESULTS: The characteristics of the child FE model proved to be close to the Hybrid III and child volunteer corridor. In the ECE R44 sled test simulations using the child FE model, the head movement down and head rotation were large in the 5-point harness CRS, and chest deflection was large in the tray shield CRS. In both CRS types, the whole spine flexed in the child FE model. This behavior is different from that of the Hybrid III, where the thorax spine is stiff and only the cervical spine and lumbar spine flex. CONCLUSIONS: Although this child FE model has several limitations in areas such as the anatomical shapes and material properties of a child, this model can be a useful tool to examine the behavior of a child in impacts, which may be difficult to predict by using the Hybrid III dummy with its stiff thorax spine box.     

Distribution patterns of larval myctophid fishes in the transition region of the western North Pacific

We examined the species composition and horizontal distribution of myctophid fish larvae in the transition region of the western North Pacific during the early summer. In total, 4,760 myctophid larvae were collected at 44 stations; 18 species of myctophids from 15 genera were collected, and the 8 most abundant species accounted for >95% of larvae. The distribution patterns of these larvae were well defined by the hydrographic structures of the study area including the Oyashio and Kuroshio fronts, the Subarctic Boundary, and a warm core ring. The horizontal distribution patterns of the eight dominant species were categorized into three groups: northern transition water (Stenobrachius nannochir, Tarletonbeania taylori, and Lampanyctus jordani), southern transition water (Symbolophorus californiensis, Diaphus theta, and Nannobrachium regale), and Kuroshio (Myctophum asperum and Diaphus garmani). The Subarctic Boundary defined the distributions of the northern and southern transition-water groups. The importance of areas of western North Pacific transition water as spawning and nursery grounds for subarctic, transitional, and subtropical myctophid fishes was indicated by the relationship between the horizontal distribution patterns of larvae, juveniles, and adults and the physical oceanographic structures.Communicated by T. Ikeda, Hakodate     

Time series analysis for the estimation of tidal fluctuation effect on different aquifers in a small coastal area of Saijo plain, Ehime prefecture, Japan

Considering the current poor understanding of the seawater–freshwater (SW–FW) interaction pattern at dynamic hydro-geological boundary of coastal aquifers, this work strives to study tidal effect on groundwater quality using chemical tracers combined with environmental isotopes. In situ measurement data of electrical conductivity and groundwater level along with laboratory measurement data of hydro-chemical species were compared with tidal level data measured by Hydrographic and Oceanographic Department, Saijo City, Japan for time series analysis. Result shows that diurnal tides have significant effect on groundwater level as well as its chemical characteristics; however, the magnitude of effect is different in case of different aquifers. Various scatter diagrams were plotted in order to infer mechanisms responsible for water quality change with tidal phase, and results show that cations exchange, selective movement and local SW–FW mixing were likely to be the main processes responsible for water quality changes. It was also found that geological structure of the aquifers is the most important factor affecting the intensity of tidal effect on water quality.     

Sorption of biodegradation end products of nonylphenol polyethoxylates onto activated sludge

IntroductionRecently ,nonylphenolpolyethoxylates (NPnEO (n :numberofethoxyunits(EOs) )havebecomeaproblematicissueforthereasonthatthesecompounds,animportantgroupofnonionicsurfactants ,havebeenusedwidelyinvariousindustriesasflocculants,dispersants,emulsifie…