Competitive exclusion, a mechanism for local extinction of organisms, has been well established among taxonomically related species, including those within the same genus, family, or class in animal ...communities. This study, however, focuses on competitive exclusion that occurs across phyla, exemplified by the exclusion of a native insect by an invading exotic mammal, where food resources overlap. The hypothesis proposed in this study is that the small Indian mongoose (
Urva auropunctata
) has caused the local extinction of a burying beetle (
Nicrophorus nepalensis
) on Okinawa Is., Japan due to competition for carcasses of small vertebrates. To test this hypothesis, a comparison of beetle abundance was conducted between the area intensively controlled for mongoose and the area where mongoose control was weak or nonexistent. The former situated north of the boundary to prevent mongoose from crossing, and the latter located south of the boundary. To determine the user of carcasses on the forest floor, mouse carcasses were laid and their consumers were observed in each area. The results showed that the beetle abundance was clearly higher in the former than in the latter, and no beetles were collected where mongoose have never been controlled. The beetles often buried the mouse carcasses for their reproduction in the former, whereas in the latter, mongoose frequently consumed the mouse carcasses. These results provide evidence of competitive exclusion of the burying beetle by mongoose. This conclusion represents the first demonstration of competitive exclusion across phyla in an animal community.
•Chemical composition and hydrogen and oxygen isotopes of hot spring waters in Toyama were determined.•The origin and underground temperature condition for geothermal exploration were discussed.•High ...salinity groups of hot spring waters are a mixture of fossil sea water and meteoric water.•The low salinity groups are of meteoric origin.•There are high-temperature geothermal resources in the eastern area.
The chemical compositions, including hydrogen and oxygen isotopes, of 35 hot spring waters in Toyama Prefecture, central Japan, were analyzed to examine their geochemical characteristics and geothermal resources. The hot spring water samples were classified into two groups: low and high chloride (Cl−) concentrations of less than and greater than 2000 mg/L, respectively. The samples in the low-salinity group were determined to be of meteoric origin and Ca2+–HCO3− type. The samples in the high-salinity group were determined to be of Na+–Ca2+–Cl− type and assumed to contain a mixture of fossil seawater and meteoric water. In the eastern area of the study region, the Na+/K+ and SiO2 concentrations were lower and higher, respectively, than those in other areas, which corresponded to high-temperature geothermal resources. Thus, the subsurface information obtained in this study enabled effective use of the low to medium geothermal resources in Toyama Prefecture.
•Column flow tests were conducted to evaluate inhibitors for the prevention of silica scaling.•Nine different inhibitors were examined at concentrations up to 25mg/L.•The most effective inhibitors ...were found to be polyacrylic and phosphinocarboxylic acid salts.•The projected cost for silica scale control is on the order of 1 US cent/ton brine.•These inhibitors can be expected to be put into practical use relative to the pH adjustment method.
A number of geothermal brine column flow tests were conducted at the Sumikawa geothermal power plant to evaluate inhibitors for the prevention of silica scaling. The silica concentration of the brine was 1150mg/L and nine inhibitors were examined at concentrations up to 25mg/L. The most effective inhibitors and concentration were found to be polyacrylic and phosphinocarboxylic acid salts and 1mg/L, respectively that higher concentrations were not necessarily better in suppressing scaling and generally the inhibiters were better than acidification. The projected cost associated with this inhibition method is close to that of the standard pH adjustment method.
The chemical carrier doping of molecular Mott insulators has been poorly investigated to date due to its difficulty. In this study, iodine doping of a molecular Mott insulator, lithium phthalocyanine ...crystallized in the x‐form (x‐LiPc), was performed to obtain metallic x‐LiPcI. Crystal structure analysis revealed that iodine atoms penetrated channels of x‐LiPc and formed one‐dimensional chains. The Raman spectroscopy of x‐LiPcI indicated the existence of linear I5−, demonstrating a transition from a half‐filled band of the Mott insulating state to a 2/5‐filled band of the metallic state. Electrical resistivity measurements confirmed the metallic nature of x‐LiPcI, whereas a thermally activated behavior was observed for pristine x‐LiPc. Furthermore, the x‐LiPc Mott insulator was reproduced by dedoping iodine from x‐LiPcI, suggesting that the electronic state can be reversibly tuned between the Mott insulating and metallic states by chemical doping and dedoping.
Chemical carrier doping of an x‐LiPc molecular Mott insulator (Pc=phthalocyanine) induced an insulator–metal transition, and the obtained metallic x‐LiPcI reverted to the pristine x‐LiPc Mott insulator through dedoping iodine. The advent of the reversible insulator–metal transition by doping and dedoping of the molecular Mott insulator could lead to a new class of strongly correlated materials.
Mesoporous silica was successfully synthesized for the first time using geothermal water from the Onuma Geothermal Power Plant, Akita Prefecture, Japan. Cetyltrimethylammonium bromide (CTAB) was used ...as an organic template for the synthesis. CTAB with a concentration of 2.4 × 10
mol/L was reacted for 30 min with geothermal water at a temperature of 90 °C, which had a total silicic acid concentration of 475 mg/L (SiO
), at pH 7.0, pH 8.2 (raw water) and pH 9.0. By calcination of the resulting precipitate at 550 °C, mesoporous silica with a pore size of about 2.8 nm and a specific surface area of > 800 m
/g was formed. The total silicic acid concentration in the solution after formation of the mesoporous precipitates was reduced to < 280 mg/L, indicating efficient recovery of supersaturated silicic acid from geothermal water. The monosilicic acid in geothermal water plays an important role in the formation of mesoporous silica. Production of mesoporous silica by our method will contribute not only to prevention of silica scale formation in the piping systems of geothermal power plants but also to its use as an industrial resource.
Oxygen isotopes, major and minor chemical compositions of 23 groundwater and 5 river water samples from the southern part of Nanto City were analyzed. From these results, the possibility of ...groundwater heat utilization was discussed. The water temperatures fluctuated between summer and winter. The groundwater in this area nearby Sho River is strongly influenced by river water infiltration and most groundwater in other areas is considered to be derived from precipitation. The Ca
2+
, HCO
3
−
, and SiO
2
concentrations increase due to reactions with rocks during water flow from the surrounding mountains to the alluvial fan areas. In some areas, Fe scale (goethite) is assumed to be precipitated from groundwater in heat exchangers and water pipes. Based on these results, an area around Sakuragaike potentially suitable for utilization of groundwater heat was selected for study.
A hydrogen bond (H-bond) is one of the most fundamental and important noncovalent interactions in chemistry, biology, physics, and all other molecular sciences. Especially, the dynamics of a proton ...or a hydrogen atom in the H-bond has attracted increasing attention, because it plays a crucial role in (bio)chemical reactions and some physical properties, such as dielectricity and proton conductivity. Here we report unprecedented H-bond-dynamics-based switching of electrical conductivity and magnetism in a H-bonded purely organic conductor crystal, κ-D3(Cat-EDT-TTF)2 (abbreviated as κ-D). This novel crystal κ-D, a deuterated analogue of κ-H3(Cat-EDT-TTF)2 (abbreviated as κ-H), is composed only of a H-bonded molecular unit, in which two crystallographically equivalent catechol-fused ethylenedithiotetrathiafulvalene (Cat-EDT-TTF) skeletons with a +0.5 charge are linked by a symmetric anionic O···D···O(-1)-type strong H-bond. Although the deuterated and parent hydrogen systems, κ-D and κ-H, are isostructural paramagnetic semiconductors with a dimer-Mott-type electronic structure at room temperature (space group: C2/c), only κ-D undergoes a phase transition at 185 K, to change to a nonmagnetic insulator with a charge-ordered electronic structure (space group: P1). The X-ray crystal structure analysis demonstrates that this dramatic switching of the electronic structure and physical properties originates from deuterium transfer or displacement within the H-bond accompanied by electron transfer between the Cat-EDT-TTF π-systems, proving that the H-bonded deuterium dynamics and the conducting TTF π-electron are cooperatively coupled. Furthermore, the reason why this unique phase transition occurs only in κ-D is qualitatively discussed in terms of the H/D isotope effect on the H-bond geometry and potential energy curve.
To mitigate the impact of clear-cutting, strip-cutting has been prescribed in Japan. When harvesting trees, logging to construct strip roads is often conducted in adjacent forests. To evaluate the ...impacts of these logging practices, we collected necrophagous silphid and dung beetles in conifer plantation stands that were connected and partly harvested by strip-cuttings and clear-cuttings, with the construction of strip roads a few months before trapping. The abundances of two of the five species abundant in the uncut forests and the total beetle biomass (dry weight) were higher at the centers of 40-m-wide strip-cuts than near edges and/or at the centers of clear-cuts (≥ 60-m-wide). The beetle assemblages differed between the uncut forests and the uncut strips (unharvested areas of strip-cuttings). However, the abundances of four species abundant in the uncut forests and the biomass were higher in the uncut strips than the strip-cuts. Therefore, we concluded that strip-cutting is a better harvesting method than clear-cutting because strip-cutting mitigated the impact on the beetle assemblages in forests and the ecosystem service estimated from biomass, and the uncut strips retained the beetle assemblages and ecosystem services observed in the uncut forests. The abundances of four species abundant in the uncut forests and the biomass were lower beside the ~2.5-m-wide strip roads than in the uncut forests but were higher than in the strip-cuts, indicating that logging to construct strip roads negatively affected to the forest species and the services, but the negative effect was lower than that of 40-m-wide logging.
Seasonal variations of water temperature, electric conductivity, and oxygen isotope and chemical composition of shallow groundwaters and river waters were determined in the Sho River alluvial fan, ...western Toyama Prefecture, Japan, to examine groundwater heat utilization for indoor climate control. Samples were collected at 31 sites every 2 months for 1 year and at 11 representative sites monthly. In addition, the results of monthly precipitation amount and oxygen isotope composition of precipitation collected within the region during the same period were also taken into account. The sources of the shallow groundwaters are a mixture of river water and precipitation. The contribution of precipitation to groundwater is generally small along the Sho River but reaches as much as 80% along the Oyabe River and in the south and west of the alluvial fan. Though the origin of the groundwater differs regionally, water temperature is fixed at around 15 °C throughout the year in the northern part of the alluvial fan, and open-type ground source heat pump systems can be used for cooling and heating there, if adequate quantitative aquifer properties (exploitable groundwater amounts) are present.
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