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.
Proton-electron-coupled reactions, specifically proton-coupled electron transfer (PCET), in biological and chemical processes have been extensively investigated for use in a wide variety of ...applications, including energy conversion and storage. However, the exploration of the functionalities of the conductivity, magnetism, and dielectrics by proton-electron coupling in molecular materials is challenging. Dynamic and static proton-electron-coupled functionalities are to be expected. This feature article highlights the recent progress in the development of functionalities of dynamic proton-electron coupling in molecular materials. Herein, single-unit conductivity by self-doping, quantum spin liquid state coupled with quantum fluctuation of protons, switching of conductivity and magnetism triggered by the disorder-order transition of deuterons, and their external responses under pressure and in the presence of an electric field are introduced. In addition, as for the functionalities of proton-d/π-electron coupling in metal dithiolene complexes, magnetic switching with multiple PCET and vapochromism induced by electron transfer through hydrogen-bond (H-bond) formation is introduced experimentally and theoretically. We also outlined the basic and applied issues and potential challenges for development of proton-electron-coupled molecular materials, functionalities, and devices.
Organic acid–base salts have attracted increasing attention as a promising candidate of anhydrous proton conductors. In this study, we have successfully disclosed the relationship between proton ...conductivity and hydrogen-bond (H-bond) interactions in such kinds of organic salts, composed of dicarboxylic acid and imidazole. We have grown high-quality single crystals of imidazolium succinate (Im-Suc) or glutarate (Im-Glu) with two-dimensional H-bonding networks and measured the proton conductivity within and perpendicular to the networks. On the basis of the observed “intrinsic” proton conductivities without grain boundary contributions, their relationship to the crystal structure and molecular arrangement was investigated in detail. Importantly, in both materials, the proton conductivities within the H-bonding networks are almost 2 orders of magnitude higher than those perpendicular to the networks, demonstrating that the proton conduction is highly mediated by the H-bonds. In addition, a suitable combination and arrangement of acid and base molecules for realizing high proton conductivity is discussed in terms of their proton donating/accepting abilities (pK a) and molecular motions. These results provide important insights into the effects of H-bonds on proton conductivity in this kind of anhydrous organic acid–base salts.
•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.
We report the synthesis, structures, and transistor properties of benzothienobenzothiophene (BTBT) derivatives tailored by introducing methoxy groups at the 2,3- and 2,3,7,8-positions ...(2,3-dimethoxy-BTBT: BTBT(OMe)2 and 2,3,7,8-tetramethoxy-BTBT: BTBT(OMe)4 ). Both of these compounds form a herringbone packing in the crystal; however, their molecular arrangements are significantly different: the tetramethoxy derivative BTBT(OMe)4 shows no dimerization, whereas the dimethoxy derivative BTBT(OMe)2 shows significant tetramerization with two dimers. This difference, attributable to the difference in the substitution pattern of the methoxy groups or the molecular symmetry, leads to a drastic difference in their charge transport properties. In the vapor-deposited thin films, BTBT(OMe)4 exhibits a crystalline architecture similar to the bulk phase stabilized by weak hydrogen bonds, showing good p-channel transistor performance, while BTBT(OMe)2 exhibits an amorphous-like structure without any observable transport properties.
Formation of a partially charge-transfer or partially oxidized/reduced state has been one of the most important requirements for the development of highly conducting molecular materials, such as ...organic metals and superconductors. This requirement has been fulfilled by combining appropriate electron-donor and acceptor molecules to construct multi-component molecular complexes/salts, such as (TTF+0.59)(TCNQ–0.59) and (BEDT-TTF+0.5)2X–, where TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane, BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, and X = monovalent inorganic anion. Here, we propose a methodology to fulfill this requirement by a single neutral molecule; namely, we have connected two TTF+0.5-type partially oxidized π-skeletons through a boron anion to design a purely organic zwitterionic neutral radical {(PDT-TTF-Cat) 2 + B – } • . This molecule was successfully obtained as air-stable crystals containing solvent tetrahydrofuran (THF) molecules. Measurements of electrical resistivity, magnetic susceptibility, and X-ray diffraction reveal that the partially oxidized state is certainly formed, which enables realization of a 3/4-filled electron band. Furthermore, this system has intramolecular charge degrees of freedom, attributable to the two TTF+0.5 π-skeletons introduced into the molecule. The resulting interplay of intra- and intermolecular charge degrees of freedom (or simply, intra- and intermolecular electronic interactions) has led to multi-step phase transitions and crossover, providing unique strongly correlated electron properties, such as the formation of a three-dimensional charge-ordered dimer-Mott insulating state and its melting triggered by disorder–order transformation of the co-crystallized solvent THF molecules at low temperatures.
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.
•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.
Retention forestry and small-sized clear-cuttings are thought to partially mitigate the impacts of logging. To evaluate the impacts of these two harvesting methods, a variety of logging operations ...were conducted in mature Sakhalin fir plantation forests in Hokkaido, northern Japan. The stands were logged with the following approaches: dispersed retention of naturally regenerated broad-leaved trees in large (100 trees/ha), medium (50), or small (10) amounts; 60 × 60 m aggregated retention; quadrilateral small-sized (ca 1-ha) clear-cutting; and whole clear-cutting. We collected necrophagous silphid and dung beetles from these stands and from unharvested natural broad-leaved forests and plantation forests using carrion-baited pitfall traps. All logging operations clearly affected the beetle assemblages. The 0.36 ha unharvested forest patches under aggregated retention did not act as refugia for forest species because their assemblages were almost identical to those outside the forest patches and in the whole clear-cuts. However, the total abundance of forest species and, specifically, the abundances of two dominant forest species were significantly and positively related to the trunk basal area of retained trees in the dispersed retention sites. The total abundance of forest species was significantly higher in the small clear-cuts than in the whole clear-cuts. A dominant open-land species was abundant in the harvested areas irrespective of the type of logging operation. Thus, we concluded that dispersed retention and small-sized clear-cuttings were beneficial harvesting methods for the beetle conservation because they conserved forest species compared to whole clear-cuttings and preserved the habitats of open-land species as well as whole clear-cuttings.
Implications for insect conservation
Our results indicated that large areas of unharvested forest patches are needed to conserve the habitat of forest necrophagous silphid and dung beetles, most species of which are adept at flying. Our results also indicated that the higher density of retained trees in dispersed retention forestry and the smaller areas of clear-cuttings were better for conserving forest species. Our findings provide useful information for selecting methods and designs of logging practices for species protection of flying insects in logged areas.
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.
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