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Omnivorous insects make foraging decisions between plant and prey resources depending on their accessibility, availability, and nutritional value. This shapes the stability and complexity of foodwebs, but also pest control services in agroecosystems. The mirid bug Lygus pratensis is a common cotton pest in China, but it also feeds on a variety of prey species. However, little is known about how different types of available resources affect its fitness and foraging behaviour. In laboratory experiments, we measured the fitness (survival, longevity and fecundity) of L. pratensis fed with bean pod only, bean + Aphis gossypii nymphs, or bean + Helicoverpa armigera eggs, and we also conducted focal observations of its foraging behaviour when provided the latter two. Adding H. armigera to its diet increased its fitness (both survival and fecundity), while adding A. gossypii was marginally detrimental. The different diets did not affect the time spent walking (searching for food resources) or preying, but significantly affected the time spent sapping bean tissue depending on L. pratensis life stage. Nymphs spent more time sapping plant when provided with H. armigera than A. gossypii (possibly through higher efficiency of handling prey). In addition, adults spent less time sapping plant than did nymphs (possibly through good efficiency of handling A. gossypii mobile prey and due to higher protein requirements). This special case of life-history omnivory highlights the complexity of natural foodwebs, where a major pest at the juvenile stage may reduce pest damage by preying on other pests species at the adult stage.

Trace fossils are structures left in a substrate as the result of the activities of living organisms. The producer of the spindle-shaped trace fossil Rosselia incorporates fine-grained organic rich material into concentric layers surrounding the central shaft. Because Rosselia is common in stressed shallow marine environments where the preservation potential of organic material is generally poor, these trace fossils may act as natural archives, recording changes in the provenance of organic material. Carbon isotope values of organic carbon preserved in laminae of the studied Rosselia typically lie around − 26‰, suggesting a primary terrestrial source. However, increased levels of S and Ca detected from XRF scanning of the laminae indicate that at least some marine material is incorporated. Examination of a diagenetically altered specimen also demonstrates that both elemental composition and δ13C values can be substantially altered diagenesis. Nevertheless, the long stratigraphic range of Rosselia, from the Cambrian to the Present, and its ubiquitous occurrence in stressed shallow-marine settings make it a potentially powerful tool to reconstruct variations in the input of organic material in settings otherwise devoid of fine-grained organic matter.

With large topographic gradients, rifted basins serve as efficient traps for particulate matter from adjacent lands and the ocean surface. However, the fate of organic carbon in the sediment, mostly unaltered by the hydrothermal activities known to occur in young rifts, remains poorly understood. In this study, we present an examination of diagenetic activities and carbon remineralization based on the first complete suite of pore-water data of sediment marginally affected by hydrothermal activities in the Southern Okinawa Trough (SOT). The sediment showed an oxygen penetration depth of 1 cm, consumption of NO3- in the top 1 cm, smeared profiles of Mn2+ and Fe2+ with the latter reaching up to 450 μmol L-1, and relatively unchanged SO42- concentrations with depth. Net production rates of dissolved species resolved from pore-water profiles provide an estimate of 1.68 ± 0.21 mmol C m-2 d-1 as the total carbon remineralization rate in the upper 30 cm sediment column, with aerobic carbon oxidation being the major pathway. The rate, one order of magnitude lower than that of the adjacent East China Sea, is attributed to the lower bottom-water temperature and carbon flux in the trough. The high carbon burial efficiency of SOT (68% of carbon reaching the seafloor and processed thereunder) reflects the combined effects of small mountain rivers and rifting-induced particle trapping.

Qualitative and quantitative assessments of fluid cycling are essential to address the role and transport of deeply sourced fluids in subduction systems. In this study, sediment cores distributed across a submarine mud volcano (SMV) offshore southwestern Taiwan were investigated to determine the characteristics of fluids generated through the convergence between the Eurasian and Phillippine Sea Plates. The low dissolved chloride concentration combined with the enrichment of 18O, and depletion of 2H of pore fluids suggest the discharge of deep freshwater formed by smectite dehydration at an equilibrium temperature of 100 to 150 °C. The upward fluid velocities, decreasing from 2.0 to 5.0 cm yr−1 at the center to a negligible value at margin sites, varied with the rate and efficiency of anaerobic methanotrophy, demonstrating the impact of fluid migration on biogeochemical processes and carbon cycling. By extrapolating the velocity pattern, the flux of fluids exported from 13 SMVs into seawater amounted up to 1.3–2.5 × 107 kg yr−1, a quantity accounting for 1.1–28.6% of the smectite-bound water originally stored in the incoming sediments. Our results imply that SMVs could act as a conduit to channel the fluids produced from great depth/temperature into seafloor environments in a subduction system of the western Pacific Ocean.

Terrestrial mud volcanism represents the prominent surface geological feature, where fluids and hydrocarbons are discharged along deeply rooted structures in tectonically active regimes. Terrestrial mud volcanoes (MVs) directly emit the major gas phase, methane, into the atmosphere, making them important sources of greenhouse gases over geological time. Quantification of methane emission would require detailed insights into the capacity and efficiency of microbial metabolisms either consuming or producing methane in the subsurface, and establishment of the linkage between these methane-related metabolisms and other microbial or abiotic processes. Here we conducted geochemical, microbiological and genetic analyses of sediments, gases, and pore and surface fluids to characterize fluid processes, community assemblages, functions and activities in a methane-emitting MV of southwestern Taiwan. Multiple lines of evidence suggest that aerobic/anaerobic methane oxidation, sulfate reduction and methanogenesis are active and compartmentalized into discrete, stratified niches, resembling those in marine settings. Surface evaporation and oxidation of sulfide minerals are required to account for the enhanced levels of sulfate that fuels subsurface sulfate reduction and anaerobic methanotrophy. Methane flux generated by in situ methanogenesis appears to alter the isotopic compositions and abundances of thermogenic methane migrating from deep sources, and to exceed the capacity of microbial consumption. This metabolic stratification is sustained by chemical disequilibria induced by the mixing between upward, anoxic, methane-rich fluids and downward, oxic, sulfate-rich fluids.

Local dopant compositions within individual α-Sialon grains were measured by analytical electron microscopy (AEM) in hot-pressed CaxSi12−3xAl3xOxN16−x (x = 0.3–1.4) ceramics. The reduction of local x values from the nominal dopant compositions is about 40% in general, and it reaches 60% for the end member (x = 1.4) which contains inclusions of AlN-based 21R phase. This results exhibit stronger departures from x than the previous report of 30% dopants missing in α-Sialon phase by electron probe micro-analysis (EPMA) [J Eur Ceram Soc 19:1637, 1999]. Amorphous films of ~1 nm thick were commonly found at grain boundaries (GBs), which could only take a small fraction of undetected dopants while the film composition exhibits a quite different behavior. The general presence of GB films can rationalize the discrepancy between AEM and EPMA results by their differences in probe size and detection geometry, while the much larger gap in the end member suggests the existence of Ca-rich glasses in the intergranular regions. By excluding this end member, a linear relation between dopant solution and lattice expansion is restored in α-Sialon structure, which leads to 20 and 80% increases of the expansion coefficients from those given in the previous and original reports, respectively. This study not only demonstrated the necessity of solubility study in ceramics by AEM refinement, but also opens a new front to correlate the solution behavior with the intergranular glass/amorphous structures, both were regarded so far as largely independent.

The isothermal oxidation behavior of Cr2AlC ceramics oxidized in air at 1,100 and 1,250 °C for 20 h was studied. The phase compositions and microstructure of the oxidized surface were identified and observed by XRD and electron probe microanalysis (EMPA), respectively, while the cross sections of oxidized samples were also examined by EMPA equipped with energy dispersive spectrum capabilities. The results indicated that the oxidation of Cr2AlC samples was carried out by the outward diffusion of Al, together with small amounts of Cr, and the inward diffusion of O to form a surface layer of α-Al2O3, while carbides (Cr7C3 and Cr3C2), rather than oxides (Cr2O3), were formed in a layer under the surface. The mass gain per unit surface area of oxidized Cr2AlC followed a parabolic relation with oxidation time, and the parabolic rates, kp, for oxidation at 1,100 and 1,250 °C were 1.1 × 10−12 and 7.1 × 10−10 kg2 m4 s−1, respectively.

On the basis of the assumption that ω 2 model accords with source displacement spectra of moderate-small shocks, we calculate the apparent stress values of 1 020 moderate-small shocks recorded by the Digital Seismic Network of Yunnan Province by using the low-frequency flat level and corner frequencies. The results show that the apparent stress is of good significance in earthquake prediction. The moderate-small shock with apparent stress larger than 0.9 MPa can be used as a referential index to predict moderate-strong earthquakes in Yunnan area. And its relevant predictability evaluation (R value) has a high confidence level.

Thermodynamic assessment in the ternary systems ZrO2-CeO2-Y2O2 , ZrO2-CeO2-Ce2O3 and the limiting binaries ZrO2-Y2O3, ZrO2-CeO2 ,CeO2-Y2O2, ZrO2-Ce2O3, CeO2-Ce2O3 as well as the modeling for oxides are reviewed comprehensively. Based on the recent estimations on the YO1,5-CeO2, ZrO2-CeO2 and ZrO2-YO1,5 systems, isothermal sections at 1 273 and 1 973 K of the ternary CeO2-ZrO2-YO1,5 system are calculated. In the system of ZrO2-CeO2-Ce2O3, the complex relation between the nonstoichiometry (y) in CeO−y , the composition of the ZrO2-CeO2 solid solution and the oxygen partial pressure (P o 2) for different ZrO2 containing solid solutions Ce2Zri2−y are evaluated from 1 473 to 1 773 K. The relation between the degree of Ce+4 reduction to Ce+3 under different P 0 2 in the fluorite CeO2−y and Ce z Zr1−z O2−x solid solutions at different temperatures can be used as a guide in the development of functional ceramics.

Y0.67Si9Al3ON15 and Dy0.4Y0.3Si8.85Al3.15O1.05N14.95 ceramics were prepared by Spark Plasma Sintering (SPS) with and without heat treatment at 1700°C for 7 h or 17 h, and their optical transmittance were investigated over the wavenumber range 4000–1500 cm−1. The results showed that the assemblages of the SPS-ed samples consisted of single crystallized α-sialon phase in both compositions. EDS analysis indicated that α-sialon was mainly stabilized by Dy3+ in the multi-cation (Dy,Y)-α-sialon composition. The SPS-ed specimens showed relatively high optical transmission properties, and the maximum transmittance reached around 65% at 2800 cm−1 for 0.5 mm thick specimens of both compositions. The 7 h heat treatment caused the formation of small amount of melilite phase, resulting in non-uniform microstructure and decrease in optical transmittance. Extended heat treatment for 17 h led to more homogenous microstructure and increased the transmittance to some extent. Less melilite was formed in the multi-cation (Dy,Y)-α-sialon composition than in the single cation Y-α-sialon after heat treatment, and the transmittance of (Dy,Y)-α-sialon was also higher than that of Y-α-sialon.

A proper powder preparation was used to develop α-Sialon single crystals as seeds. The microstructure and fracture toughness of seed-containing α-Sialon ceramics sintered by hot-pressing were investigated. The specimen without seeding consisted of fine grains and a small amount of coarse grains. Specimens seeded with α-Sialon single crystal particles presented a large amount of elongated α-Sialon grains. The aspect ratio and the amount of elongated α-Sialon grains can be tailored by using different sizes and amounts of the seeds. The fracture toughness of seed-containing α-Sialon ceramics is improved, which is attributed to grain pullout and bridging of elongated grains.

Ca-α-sialon compacts pressureless-sintered to intermediate temperatures, which consisted of both α-sialon and unreacted α–Si3N4 grains, were investigated with transmission electron microscopy for an overall composition Ca1.8Si6.6Al5.4O1.8N14.2. Special attention was paid to identification of the possible crystallographic orientation between a-sialon and the α–Si3N4 particles. In contrast to the frequently occurring heteroepitaxial nucleation of α-sialon in rare-earth-doped samples with low x values, this study showed that most of the newly formed α-sialon grains had no epitaxial orientation relationship with the α–Si3N4 particles, suggesting nonepitaxial heterogeneous nucleation to be a more probable mechanism for the Ca–α-sialon phase with high Ca concentrations.

Ca α-Sialon compacts pressurelessly-sintered to the intermediate temperature (1 450°C) were investigated with TEM for an overall composition Ca1.8Si6.6Al5.4O1.8N14.2. It was found that in most cases, the newly-formed α-Sialon grains had no epitaxial orientation relationship with the Si3N4 particles; only occasionally heteroepitaxial nucleation of α-Sialon on α-Si3N4 was detected. Further EDAX analysis revealed a much higher Ca concentration in the non-epitaxially nucleated α-Sialon than in the heteroepitaxially nucleated α-Sialon. Thus a possible correlation between the concentration of metal cations in the α-Sialon structure and the nucleation mechanism has been proposed, i.e. α-Sialon compositions with higher Ca concentration show a stronger trend of non-epitaxial nucleation.

Two R-α-sialon (R0.6Si9.3Al2.7O0.9N15.1, R=Nd and Er) compositions were first fired at 1750°C/25 min and 1650°C/2 h respectively for completion of the α → α′ phase transformation. Elongated α-sialon grain morphology was developed in both samples after being re-fired at 1800°C for different periods of time. The growth in width of R-α-sialon grains is controlled by diffusion in the liquid, while the length growth tends to be interfacial reaction controlled. The anisotropic growth of R-α-sialon is attributed to the large difference in the growth rate constant between the length and the width directions of the grain.

The influence of processing on microstructural development of Ca α-sialon composition (CaxSi12−3xAl3xOxN16−x) with x = 1.8 was studied by dwelling at different intermediate temperatures before reaching the final sintering temperature. The microstructural observation results have showed the different aspect ratios of elongated grains obtained by the various processing conditions, reflecting the effect of the number of nuclei of α-sialon on morphology of grains during sintering. Improved toughness was achieved by applying low temperature dwelling for Ca α-sialon compositions with low x values. The toughness showed an increase of 33% and 16% for x = 0.6 and 1.0 compositions respectively with middle dwelling processing at 1350°C for 3 h before reaching 1750°C for 1 h by hot-pressing.

Multi-cation α-Sialons ceramics containing calcium and magnesium for the compositions ((Ca,Mg)xSi12 − 3xAl3xOxN16 − x), where x equals 0.6 and 1.0 with the different atomic ratios of Ca to Mg, were fabricated by hot-pressing. An exploration for Ca,Mg-α-Sialon involving phase compositions, cell dimensions, microstructure and mechanical properties were carried out in the present work.

The uplift of the Tibetan plateau is generally regarded as a response to the convective removal of the lower portion of the thickened Asian lithosphere1. This removal is also thought to be responsible for the east–west extension2 that took place during the India–Asia collision. The timing of these events has been a subject of great interest for understanding mountain-building processes, collisional tectonics and the influence of these processes on climate change3,4. In western Tibet, potassic lavas related to east–west extension were found to have been extruded over the past 20?Myr (refs 5, 6). Here we report the widespread occurrence of magmas in eastern Tibet which show similar geochemical signatures to the potassic lavas to the west but formed 40–30?Myr ago. These magmatic activities suggest a diachronous uplift history for the Tibetan plateau, with the convective removal of the lower lithosphere inducing rapid uplift in the east beginning some 40?Myr ago and in the west about 20?Myr later. This observation is consistent with sedimentation records from the Ganges–Brahmaputra delta to the Bengal fan7,8 and can better account for the tectonically driven models for strontium isotope evolution in the ocean9 and global cooling10 over the past 40?Myr.

Rietveld refinements have been used to determine the structure of Y2Si3O3N4 from X-ray data and Nd2Si2.5Al0.5O3.5N3.5 from neutron powder diffraction data. The refinements show that in the melilite phase Y2Si3O3N4 and melilite solid solution Nd2Si2.5Al0.5O3.5N3.5 the distributions of cations and anions are almost identical. They are analogous to the akermanite (Ca2MgSi2O7) structure, with Si/Si,Al atoms at the origin and centre of the unit cell and with four N/N,O atoms forming the SiN4/(Si,Al)(N3.5O0.5) tetrahedra which share corners with SiO2N2/(Si,Al)O2.25N1.75 tetrahedra to form a continuous sheet structure. Each Y3+ or Nd3+ ion is surrounded by eight N/O atoms forming the coordination polyhedron in Y2Si3O3N4 and Nd2Si2.5Al0.5O3.5N3.5 respectively. The arrangement of Al, Si atoms in the tetrahedra in Nd2Si2.5Al0.5O3.5N3.5 structure is also discussed.

We report the glass-forming region at 1700°C for N-rich compositions of the Sm-Si-Al-O-N system

The Taiwan Chelungpu Drilling Project (TCDP) has provided an unprecedented opportunity to reveal a terrestrial subsurface microbial ecosystem that has possibly experienced continuous disturbance by the arccontinental collision since 5 Ma. The drilling penetrated Pliocene-Pleistocene sedimentary rocks to a depth of 2000 meters below the land surface (mbls) and encountered two major fault zones. Sixteen samples retrieved from the drilled cores at depths between 464 to 1451 mbls were examined to characterize microbial community structures through cultivation-based approaches. Cultivation experiments were performed with various media at temperatures ranging from 30 to 50¢XC. The results indicate that fermenters and heterotrophic sulfate reducers, using complex organic carbon, were ubiquitously present in most samples. Acetate-utilizing and H2 ¡Vutilizing sulfate reducers were restricted to shallower intervals along the depth profile. Iron reducers and methanogens were only cultivated in a few shallow samples. Twelve pure strains including 8 fermenters, 3 iron reducers and 1 sulfate reducer originally enriched at 30 or 40¢XC were isolated and identified with 16S rDNA sequence analyses. They were phylogenetically affiliated with Firmicutes, Bacteriodes, Actinobacteria, and Proteobacteria in various degrees of similarity. The presence of metabolism was not correlated with lithology, depth, temperature and the appearance of fracture throughout the core. The ubiquitous appearance of fermentation and organotrophic sulfate reduction suggests that organic carbon sources were readily accessible in this deep terrestrial subsurface environment. These results infer that the foreland sedimentary strata disturbed by tectonic activities over a geological time scale might support a heterotrophy-dominated deep terrestrial subsurface microbial ecosystem.