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We investigated the relationship between digestive function and ecological distribution for four related species of Gastropoda (Cerithidea rhizophorarum, Cerithidea cingulata, Batillaria multiformis, and Batillaria attra- mentaria) inhabiting the Tanaka River estuary (Mie Prefecture, Japan). We compared the digestive enzyme activities for four hard degradable carbohydrates, namely, cellulose, mannan, xylan, and laminarin. Among the investigated four species, Cerithidea rhizophorarum showed the highest cellulase, mannanase, xylanase, and laminarinase activi- ties, and was also dominantly distributed in the estuary reed bed. The results of CN stable isotopic analysis suggested that this species assimilated organic matter derived from reeds. Hard degradable carbohydrates, including plant com- ponents derived from the reed bed or from dry land, accumulate in the sediment of estuaries. Estuarine benthic ani- mals are assumed to consume these accumulated hard degradable carbohydrates, as well as microphytobenthos and particulate organic matter (including phytoplankton). Our present findings suggest that Cerithidea rhizophorarum is dominant in reed beds because it can more efficiently digest plant-derived carbohydrates than can Cerithidea cingu- lata, B. multiformis, and B. attramentaria. To the best of our knowledge, ours is the first study to demonstrate that the specific ecological distribution of related animal species with similar ecological traits can be explained by the effi- ciency of their digestive enzyme activity.

Background On March 11, 2011, the Tohoku district was struck by the most powerful known earthquake to hit Japan. Although stress-induced heart diseases rise after strong psychosocial stress, little is known about the characteristics of heart failure (HF) caused by psychosocial stress related to earthquakes. Methods We examined patients admitted to our hospital for HF during a three-week period between March 11 and March 31, 2011 (Disaster group) and compared them to patients during the corresponding period of 2010 (Non-Disaster group). Results The number of patients was larger in the Disaster group (n = 30, 18 men, 12 women; mean age 77.3 ± 9.8 years) than in the Non-Disaster group (n = 16, 8 men, 8 women; mean age 77.3 ± 11.6 years). A total of 14 of 30 patients (46.7%) in the Disaster group did not have past history of admission for HF, compared to 2 patients (12.5%) in the Non-Disaster group (p = 0.02). The number of patients with hypertension was larger in the Disaster group than in the Non-Disaster group (53.3% vs. 37.5%, p = 0.04). The number of patients with atrial fibrillation was also larger in the Disaster group than in the Non-Disaster group (56.7% vs. 25.0%, p = 0.03). Left ventricular systolic ejection fraction (EF) did not differ between the Disaster and Non-Disaster groups (45.2 ± 17.8% vs. 45.6 ± 14.0%, p = 0.46), however, the proportion of patients whose EF was more than 45% were significantly higher in the Disaster group more than in the Non-Disaster group (56.7% vs. 43.8%, p = 0.04). The in-hospital mortality rate for patients in the Disaster group was higher than in the Non-Disaster group (20.0% vs. 6.3%, p = 0.04). Conclusion The incidence and in-hospital mortality rate of HF increased after the Great East Japan Earthquake, suggesting that psychosocial stress brought on by such a disaster could lead to the development of HF with preserved EF more than that with reduced EF.

Identifying sources of particulate organic matter (POM) is important for clarifying fundamental mechanisms by which lake food webs are sustained. We determined carbon and nitrogen stable isotope ratios of POM in near-shore waters of Lake Biwa, a large, meso-eutrophic lake in Japan, to estimate relative contributions of terrigenous particulate organic carbon (T-POC), plankton-derived POC (P-POC) and epilithon-derived POC (E-POC) to POC in near-shore waters. Samples were collected during different months (November, February, May and July) at 29 sites located near the mouth of tributary rivers with different discharge and catchment land use. The data revealed that POC mainly consisted of P-POC and T-POC, with relative contributions varying widely over season and among locations. E-POC generally contributed little to the near-shore POC. Path analyses revealed that the concentration of riverine POC whose isotopic signatures were similar to those of rice straws increased with a larger %paddy field area in the catchment of tributary rivers, which subsequently enhanced T-POC inputs to near-shore waters through riverine transportation. Furthermore, our results suggested that T-POC contribution was influenced, with a time lag, by wave-driven turbulence and shore topography, which appear to affect sedimentation and resuspension of T-POC.

In the present work, FLDs of AZ31 magnesium alloy sheet for non-proportional strain paths were investigated by performing two-step stretch forming experiments at various forming speeds (3, 30 and 300 mm.min-1) at elevated temperatures of 150, 200 and 250°C. The forming limit strainSuperscript texts, both for proportional and non-proportional deformations, increased with temperature rise and with decreasing forming speed. A FLC after a uniaxial pre-strain lies outside of the proportional FLC for a given condition of temperature and forming speed, whereas a biaxially pre-strained FLC lies inside of the proportional FLC. It was found that the accumulated effective plastic strain and the direction of plastic strain increment at the final stage of forming are two major factors that influence the forming limits for non-proportional deformations.

We tested the hypothesis that in shallow, eutrophic Lake Kasumigaura, the concentration of particulate phosphorus (PP) is controlled by biogenic P (P in living or dead phytoplankton and bacterial cells), rather than by resuspension of inorganic P in sediment. Increases in wind velocity and turbidity were associated with bottom shear stress exceeding the critical value for the lake (τc=0.15Nm(-2)); this increased turbidity was due to sediment resuspension. However, concentrations of PP; HCl-extractable, reactive P in PP (P-rP); and HCl-extractable, non-reactive P in PP (P-nrP) were not correlated with wind velocity (PP vs. wind velocity: r=0.40, p>0.05). Rather, the P-nrP concentration accounted for approximately 79% of PP, and the concentrations of PP, P-rP, and P-nrP were correlated with the particulate organic carbon (POC) concentration (POC vs. PP: r=0.90, p

Terrestrial–aquatic linkages of Japanese mountain lake ecosystems were examined to identify terrestrial carbon input into mountain lakes and the importance of the allochthonous carbon for the ecosystem metabolism of aquatic food webs therein. Stable carbon isotope analyses revealed that the flux of terrestrial dissolved organic matter from the surrounding catchments was relatively larger in smaller lakes with higher drainage ratios and tended to predominate carbon cycling in the epilimnetic water of such lakes. However, the metabolic balance of epilimnetic lake waters was net autotrophic or approximately in balance between gross primary production (GPP) and community respiration (CR) rates, suggesting that allochthonous organic matter generally subsidizes benthic and hypolimnetic communities. Empirical models established based on these observed GPP and CR values predict that climate change may increase carbon flows from both autochthonous and allochthonous pathways in epilimnetic communities of unproductive mountain lakes, directly through the functional dependence of community metabolism on the projected temperature rise and indirectly through the increased supply of terrestrial organic matter.

The LeX glycoside having an N3 moiety at the ω position, which was prepared by using living cells from GlcNAcO(CH2)12N3 as a starting material, was efficiently introduced into a trivalent-type carbosilane core scaffold by means of Huisgen cycloaddition reaction to yield the corresponding glycocluster having three LeX moieties at each end. Structural elucidation of the product was performed by a combination of NMR and mass spectroscopic analyses, and the results of the analyses supported the structure of the glycocluster. Evaluation of the glycocluster was carried out using Lotus lectin as a model lectin. Environmental changes of tryptophan residues located at or near the binding sites of Lotus lectin caused fluorescence intensity change.

Differences in biogenic phosphorus (P) compounds between sediment and suspended particles in aquatic environments are important for understanding the mechanisms of internal P loading, but these differences are still unknown. We used solution-state (31)P-nuclear magnetic resonance spectroscopy ((31)P NMR) with NaOH-ethylenediaminetetraacetic extraction to detect the multiple P compounds in suspended particles and sediment in the eutrophic Lake Kasumigaura, including orthophosphate monoesters, orthophosphate diesters, pyrophosphate, and polyphosphate. We tested the hypothesis that there is a significant difference between these groups in suspended particles and sediment. Biogenic P other than orthophosphate was found in significantly higher proportions in suspended particles (74.3% of total P) than in sediment (25.6%). Orthophosphate monoesters were comparatively more abundant in suspended particles, as indicated by the ratio of orthophosphate diesters to monoesters (average, 0.31 for suspended particles; 1.05 for sediment). The compounds identified as orthophosphate monoesters by (31)P NMR spectroscopy originated mainly from phospholipids (α-glycerophosphate and β-glycerophosphate) and ribonucleic acid (RNA-P), whereas the orthophosphate diesters included mostly DNA (DNA-P). These results suggest that the dynamics of orthophosphate diesters, the production of DNA-P, or the degradation of phospholipids, play an important role in P cycling in Lake Kasumigaura.

Geological and geographical parameters including land use, stratigraphic structure, groundwater quality, and N- and O-isotopic compositions of nitrate in groundwater were investigated to elucidate the mechanism of groundwater pollution by NO3− in the agricultural area of Katori, Chiba, Japan. An aquitard distributed in the western part of the study area has produced two unconfined aquifers. The average concentrations of NO3− and dissolved oxygen (DO) were high in the aquifer above the aquitard (7.5 and 7.6 mg/L, respectively) and in the aquifer of the eastern part of the study area that was not influenced by the aquitard (11.9 and 7.8 mg/L, respectively); however, the levels in the aquifer under the aquitard were relatively low (2.2 and 3.7 mg/L, respectively). The δ15N and δ18O values of NO3− generally increased exponentially in the groundwater that flowed into the aquifer under the aquitard as the concentration of NO3− decreased, although this decrease in NO3− also occasionally occurred without isotopic changes. These results indicated that the aquitard prevented the penetration of NO3−, DO, and gaseous O2. Under the aquitard, denitrification and dilution with unpolluted water that entered from natural forested areas reduced the NO3− concentrations in the groundwater. The major sources of NO3− in groundwater in the study area were estimated to be NH4-chemical fertilizer, livestock waste, and manure.

A new type of high-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) system with ultraviolet (UV) absorbance detection and non-dispersive infrared (NDIR) detection of total organic carbon is described. The introduction of an online degassing tube and a low-volume HPLC column helped to reduce the analytical time and increase the sensitivity of the SEC system. This study is the first in which linear calibration curves (R(2)>0.99) were obtained for both UV absorbance and NDIR data for polystyrene sulfonate standards, which are the most suitable standards for molecular size analysis of aquatic humic substances as well as dissolved organic matter (DOM). Using the calibration curves, the molecular size distribution of DOM in water collected from Lake Kasumigaura and in pore water from lake sediments was estimated. Most of the DOM had a molecular weight less than 4000 Daltons (Da), and the amount of low-molecular-weight DOM (∼ 2000 Da) with low UV absorbance increased with depth in the sediment pore water. This result shows the importance of combining quantitative analysis by NDIR detection with qualitative analysis by UV detection to determine the chemical and physical properties of DOM. The possible sources and reactivity of DOM in Lake Kasumigaura and its sediment pore water are also discussed.

The stable nitrogen (N) isotope ratio (δ15N) has been used to examine the anthropogenic N input (i.e., septic water, wastewater, and manure) to aquatic ecosystems, because anthropogenic N generally has a δ15N signature distinct from that found in nature. Aquatic organisms and the derived organic matter such as sediments are reported to become increasingly enriched in 15N as the human population density increases in watersheds. However, little is known about the relationship in steppe ecosystems, where the livestock population is greater than that of humans. Here, we conducted a preliminary study in the Selenga river mainstream watershed in Mongolia, which covers an area of approximately 300,000 km2. A multiple regression analysis revealed that the δ15N of the riverine sediment was significantly affected by the human population density and more significantly by livestock population density. The population density, including both humans and livestock, significantly influenced δ15N of the macrophytic Potamogeton spp. The results showed that δ15N of riverine organic matter can be an indicator of the human and livestock population density, which is likely associated with the status of N cycles in livestock-dominated watersheds.

Sediment core samples from the center of Lake Kasumigaura, Japan, were collected from 1979 to 2007 at intervals of 1 month to 5 yr. We evaluated the degree of modification in N isotope composition during sedimentation and diagenesis. We estimated the degree of isotope discrimination during diagenesis by comparing historical changes in N isotope composition of the surface sediment (top 2 cm) against the vertical profile of the isotope composition of sediment core samples (15 cm depth). The degree of 15 N enrichment during sedimentation appeared to be significant under the preferential N decomposition that occurred in the periods with low C/N ratio values of suspended particulate organic matter. We documented 15 N depletion in sediment deeper than approximately 3 cm during diagenesis. The contrasting directions of N isotope discrimination during sedimentation and diagenesis suggest changing mechanisms of isotopic shift across an oxidation–reduction boundary.

The Tuul River, which provides water for the daily needs of many residents of Ulaanbaatar, Mongolia, has been increasingly polluted by wastewater from the city's sewage treatment plant. Information on water movement and the transformation of water-borne materials is required to alleviate the deterioration of water quality. We conducted a synoptic survey of general water movement, water quality including inorganic nitrogen concentrations, and isotopic composition of nitrogen (δ 15 N-NO 3 − , δ 18 O-NO 3 − , and δ 15 N-NH 4 + ) and water (δ 18 O-H 2 O) in a wetland area that receives wastewater before it enters the Tuul River. We sampled surface water, groundwater, and spring water along the two major water routes in the wetland that flow from the drain of the sewage treatment plant to the Tuul River: a continuous tributary and a discontinuous tributary. The continuous tributary had high ammonium (NH 4 + ) concentrations and nearly stable δ 15 N-NH 4 + , δ 15 N-NO 3 − , and δ 18 O-NO 3 − concentrations throughout its length, indicating that nitrogen transformation (i.e., nitrification and denitrification) during transit was small. In contrast, NH 4 + concentrations decreased along the discontinuous tributary and nitrate (NO 3 − ) concentrations were low at many points. Values of δ 15 N-NH 4 + , δ 15 N-NO 3 − , and δ 18 O-NO 3 − increased with flow along the discontinuous route. Our results indicate that nitrification and denitrification contribute to nitrogen removal in the wetland area along the discontinuous tributary with slow water transport. Differences in hydrological pathways and the velocity of wastewater transport through the wetland area greatly affect the extent of nitrogen removal.

Recently, ultra high strength steel plate such as 1000N (950N/mm2 Class) class strength is focused as material of various type of steel structure. 1000N class steel has already applied in hydropower plant in order to enjoy its effect on weight and cost reduction. However, in building construction field, high strength steel remains unfamiliar material. There are only a few example of application of 780N/mm2 class strength steel in building field. Authors have already developed 1000N class steel plate and welding consumables for building. However, from viewpoint of actual application, structural performance under massive earthquake must be evaluated. Local area of column-to-beam connection seems be subject to large amount of strain when seismic event. So, in this report, low cycle fatigue properties of 1000N class steel and its weld was evaluated and structural experiments were conducted. As a result, it is revealed that Low fatigue property of 1000N class steel is equivalent to that of 780N class and can maintain the loading capacity under 26∼51 times of strain amplitude at cδp. Furthermore, it is also shown that structural performance can be estimated by test results of small specimen with strain calculation by FE analysis and finishing of edge of beam is effective for extension of lifetime through decrease of strain.

硝酸イオンの窒素・酸素安定同位体比(δ15N，δ18O)はその高い起源推定能から海洋，湖沼，河川，地下水での物質循環の研究に用いられてきた。1990年代半ばに開発された脱窒菌法により，硝酸イオンのδ15N，δ18Oを微量で同時に測定できるようになった。脱窒菌法で多量のサンプルを短時間に精度よく測定するには前処理ライン(N2Oガスを質量分析計に導入するための前処理)が必要不可欠である。しかしながら，こうした前処理ラインの分析機器は高額(数千万円程度)である。著者らは多くの研究室に設置されている通常の固体粉末試料の同位体測定ライン(質量分析計と元素分析計がConflo IIIで連結された測定システム)を活用し，測定精度や処理速度を落とすことなく，安価に自動前処理できるラインを開発することに成功したのでここに報告する。

Grain refinement and crystal orientation of magnesium alloy AZ31 under torsion extrusion with a square-hole die are investigated. The optimum temperature and ratio of the die rotation speed to the extrusion speed were clarified, resulting in uniformly distributed fine grains with sizes in the range 1- m over the entire cross section of the worked specimen. The crystal orientation of the specimen was determined by electron backscatter diffraction and compared with that of a conventionally extruded specimen. In the case of torsion extrusion, a very strong texture was observed along the extrusion axis, especially in the center region of the cross section. In contrast, the direction of many grains in the conventionally extruded specimen tended to be perpendicular to the extrusion axis.

Carbon and nitrogen stable isotope ratios (δ13C and δ15N) have been used for more than two decades in analyses of food web structure. The utility of isotope ratio measurements is based on the observation that consumer δ13C values are similar (

Carbon and nitrogen stable isotope ratios (δ13C and δ15N) of macroinvertebrates inhabiting littoral zones of lakes can serve as useful indicators of material loading from the watershed. We collected snails (Semisulcospira spp.) and bivalves (Unio douglasiae biwae Kobelt) from 29 littoral sites in Lake Biwa near the mouths of river tributaries with various human population density (HPD) and land-use patterns. The δ13C and δ15N signatures were determined for three potential food sources: particulate organic matter in the pelagic zone (PPOM), riverine particulate organic matter from tributaries (RPOM) and epilithic organic matter in the littoral zone (EOM). The stable isotope mixing model revealed that snails relied mainly on EOM, and bivalves on PPOM and RPOM. Multiple regression analysis showed that intersite variation in δ15N for snails was best explained by HPD, while variation in δ15N of EOM and nitrate was explained to a lesser extent by HPD. Comparison with isotope signatures of their food sources and riverine nutrients revealed that snails assimilated anthropogenic nitrogen from wastewater in the watershed. Our results also showed that the δ13C value of bivalves was marginally related to the fraction of paddy fields in the watersheds. In conclusion, the isotope signatures of macroinvertebrates inhabiting the littoral zone can be useful indicators of anthropogenic impacts from the watershed.

To improve the cold formability of AZ31 magnesium alloy sheets, we investigate texture control by rolling and annealing. The texture ideal for forming close to random orientation was obtained by annealing at 773 K before and after isothermal rolling at 298–573 K. For the randomizing process, such a high temperature in pre-annealing was essential, whereas a slightly lower temperature was acceptable for final annealing, assuming a sufficiently long annealing time. The randomized sheet could be obtained in a wide range of rolling temperatures and reductions. It could also be produced easily with a standard mill without roll heating. The microstructure of the randomized sheet consisted of relatively homogeneous grains 25–30 μm large on average. In a 90 degree V-bending test, a well randomized sheet could be bent without cracking with a minimum bending radius per thickness R/t=1.4, which was about half of that in commercial AZ31D-O sheets, in spite of manganese content of over 0.6%.

Overgrazing often lowers species richness and productivity of grassland communities. For Mongolian grassland ecosystems, a lack of detailed information about food-web structures makes it difficult to predict the effects of overgrazing on species diversity and community composition. We analysed the delta13C and delta15N signatures of herbaceous plants, arthropods (grouped by feeding habit), wild and domestic mammals, and humans in central Mongolia to understand the predominant food-web pathways in this grassland ecosystem. The delta13C and delta15N values of mammals showed little variation within species, but varied considerably with slope position for arthropods. The apparent isotopic discrimination between body tissue and hair of mammals was estimated as 2.0 per thousand for delta13C and 2.1 per thousand for delta15N, which was large enough to cause overestimation of the trophic level of mammals if not taken into account when using hair samples to measure isotopic enrichment.

Synthetic construction of a Le(x) determinant was accomplished via slightly modified Gabriel amine synthesis from three building blocks. Further transformations followed by polymerization of the Le(x) derivative gave a glycopolymer having trisaccharidic units as pendant-type epitopes. (C) 2009 Elsevier Ltd. All rights reserved.

Nitrogenous compounds with high delta(15)N values were recently found in human-dominated small rivers in the Lake Biwa area. A detailed survey was performed to determine the distribution and variation of delta(15)N values in nitrogenous compounds in a representative small river (Hebisuna River) that flows into Lake Nishinoko, an inner bay of Lake Biwa. A high delta(15)N value was detected in the lower reaches of the river and the inner bay, most likely due to denitrification. These results strongly suggest that denitrification in small river systems such as the Hebisuna watershed has contributed to (15)N enrichment in the Lake Biwa ecosystem during the past 40 years. We also observed a clear, stepwise, positive correlation between population density and delta(15)N values for particulate organic matter or sediments. These results demonstrate that delta(15)N (POM) and delta(15)N (sediment) are helpful indicators for assessing nitrogen loading from domestic sewage. Moreover, they will aid in the development of new concepts in the environmental capacity of river ecosystems and its relationship to redox conditions. Finally, our data suggest that a population density of 100-200 persons per km(2) is the upper limit for a watershed in which only simple conventional sewage treatment is in effect.

Epilithic bacterial communities play a major role in biogeochemical cycles of rivers; however, distributional patterns and controls of epilithic communities remain unclear. The objective of the present study was to examine possible environmental factors that affect longitudinal distri- butional patterns of epilithic bacterial communities in 2 rivers (Yasu and Ado Rivers) draining the Lake Biwa basin, Japan. Phylogenetic analyses were conducted using denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes and fluorescence in situ hybridization (FISH) with oligonucleotide probes targeted to small subunit rRNA. Non-metric multidimensional scaling and canonical correspondence analysis of the DGGE profile indicated that a clear shift in community composition occurred at the middle reach of the Yasu River. This shift was most closely related to variation in the nitrogen stable isotope ratio (δ 15 N) of epilithic materials (BIOENV analysis, ρw = 0.512), which is an indicator of the extent of anthropogenic nitrogen loading. The concentration of dissolved organic carbon (DOC) also affected community composition (ρw = 0.510 for the combina- tion of δ 15 N and DOC). The longitudinal pattern of the DGGE profile was less evident in the Ado River. In both rivers, FISH results indicated that Alphaproteobacteria and Betaproteobacteria gener- ally accounted for a large fraction (37 to 71%) of total bacterial abundance, indicating that species and clones affiliated with a limited number of the major phylogenetic groups occupy diverse epilithic habitats. Our results are consistent with the hypothesis that nutrients and organic matter of anthropo- genic origin are major determinants of epilithic bacterial community structure in rivers.

The rolling textures evolution of AZ31 magnesium alloy sheets is investigated by the eccentric-rolls drawing as a simulated rolling. The eccentric-rolls provides a sheet continuously changing in rolling reduction, and a exact processing temperature is ensured by uniformly heating the free-rotatable rolls together with a test piece in a furnace. The formed textures at the different rolling rates of 10 and 100 mm·s -1 showed no significant differences in any temperature and rolling reduction. The double peak texture, which appreciably improves low-temperature formability of this alloy, was obtained under rolling reduction of 22% or above at 423-523 K. On the other hand, at 573 K, the texture was typically concentric circle.

Deterioration of aquatic ecosystems resulting from enhanced anthropogenic N loading has become an issue of increasing concern worldwide, and methods are needed to trace sources of N in rivers. Because nitrate from sewage is enriched in 15N relative to nitrate from natural soils, delta(15)N values of stream nitrate (delta(15)Nnitrate) should be an appropriate index of anthropogenic N loading to rivers, as should the delta(15)N values of riparian plants (delta(15)Nplant) because they are consumers of nitrate. We determined the delta(15)N values of stream nitrate and six species of riparian macrophytes in 31 rivers in the Lake Biwa Basin in Japan. We then tested the correlation between these values and various land-use parameters, including the percentage of land used for residential and agricultural purposes as well as for natural areas. These delta(15)N values were significantly positively correlated with land use (%) that had a high N load (i.e., residential or agricultural use) and significantly negatively correlated with forest (%). These findings indicate that delta(15)N values of stream nitrate and riparian plants might be good indicators of anthropogenic inputs of nitrogen.

Low-cycle fatigue behavior during room-temperature superplastic flow was investigated for ultrafine-grained Zn–22 wt.%Al alloy. This alloy exhibited a longer fatigue life and a lower crack propagation rate than other materials at high strain amplitudes above ±5%. In addition, many cavities and secondary cracks were observed near the tips of cracks. These are probably responsible for the apparent reduction in the crack propagation rate and the long fatigue lifetime of this alloy.

We examined how nitrogen-stable isotopic signatures of food web components (basal resources, primary and lower consumers, and omnivores) in rivers change with increasing levels of human population density (HPD) in their watersheds. Samples were collected from 22 rivers flowing in the Lake Biwa basin, Japan. Among three potential resources at the base of food webs (epilithon, benthic and suspended particulate organic matter), the mean isotopic values (δ15N) of the epilithon (4.5–7.8%) were consistently higher than those of other items (1.9–4.2%) and displayed the most pronounced elevation (by 3.3%) with increasing HPD. The mean δ15N values of the individual taxa of lower consumers (bivalve, snail and caddisfly) tended to increase with increasing HPD, although the pattern and the extent of the elevation were highly variable among the taxa. These results suggest a taxon-specific feature in the N source (or sources) of lower consumers. Our data suggested that human activities (e.g. nutrient loading) potentially induce changes in the N baselines of river food webs. The major N source of bivalves appeared to be shifted from suspended particulate organic matter to other items with increasing HPD. Trophic levels of goby fish (Rhinogobius sp. OR) and shrimp (Palaemon paucidens), being estimated to be at 2.4–3.8 and 2.1–3.4, respectively, did not differ significantly among rivers with different HPD levels.

Magnesium alloys usually exhibit low ductility at the room temperature due to its hexagonal close-packed structure, but it will be improved at elevated temperature. Therefore, warm press-forming of magnesium alloy sheets is quite attractive. In order to determine the optimum condition of press-forming for magnesium alloy sheets, in the present work, the effects of strain rate, temperature and sheet thickness on the yield locus were experimentally investigated. The yield loci of magnesium alloy (AZ31) sheets with different sheet thickness (0.5 and 0.8 mm) were obtained by performing biaxial tensile tests, using cruciform specimens, at temperatures of 100, 150, 200, 250 and 300 °C at strain rates of 10 −2 , 10 −3 and 10 −4 s −1 . Based on the experimental results, the effects of strain rate, temperature and sheet thickness on the yield locus were discussed. The size of yield locus drastically decreases with increasing temperature and decreases with decreasing strain rate. In contrast with the temperature and strain-rate dependence of the yield locus, sheet thickness has no influence on the yield locus. The shape of the yield locus of magnesium sheet is far from the predictions calculated by the yield functions of von Mises, Hill and Cazacu. Instead of these, the yield functions of Logan-Hosford or Barlat is a better choice for the accurate description of biaxial tension stress–strain responses at high temperature.

We observed the seasonal occurrence and foraging behaviors of a terrestrial red mite, Balaustium murorum (Hermann), on the roof of a building in Osaka and analyzed the stable isotope ratios in the mite and three prey species to study its feeding habits. On direct observation, the adult mites formed groups and fed on small insects and anthers that had fallen on the roof. When pollen of the grass Polypogon fugax Steud. was experimentally added to the roof surface, the adult mites fed more frequently than they did without the pollen. We measured the stable isotope ratios of C and N in the mite and three prey species, P. fugax, a plant louse (Psyliidae sp.), and a cyanobacterium (Hassallia sp.), and estimated the contribution of each to the mite. This showed that P. fugax made the largest contribution, about 50%, irrespective of the estimation method. From these results, we concluded that the pollen was the most important food resource for the mite, although it is an omnivore.

The yield locus of type AZ31 magnesium alloy sheet was obtained by performing biaxial tensile tests, using cruciform specimens, at temperatures of 100, 150, 200, 250 and 300 P o PC at strain rates of 10P -2 P, 10P -3 P and 10P -4 PsP -1 P. Based on the experimental results, the effects of strain-rate and temperature on the yield locus was discussed. The size of yield locus drastically decreased with increasing temperature and decreased with decreasing strain-rate. Neither von Mises’s criterion or Hill’s can well predict the shape of the yield locus of this sheet metal. Instead of these quadratic yield functions, the yield criterion of Logan-Hosford or Barlat is a better choice for the accurate description of biaxial stress-strain responses at high temperature.

Nine species of basidiomycota and one species of ascomycota were grown in an ammonium sulphate media and on beech wood; and the general (15)N dynamic patterns of the hyphae were examined. The fungal body initially became depleted in (15)N in both the types of incubation. However, the underlying mechanisms were quite different, that is, significant fungal (15)N drop on the beech wood is associated with the fungal N reallocation and the uptake of atmospheric ammonia and/or NO(x), in addition to isotope fractionation during assimilation. Although the (15)N values of the wood-decomposing basidiocarps were generally close to the (15)N values of the wood, it does not always indicate that the wood derived N was the sole N source for the fungi throughout the growth periods as shown in our wood-decomposing experiment.