Identification of methane origins remains a challenging work as current diagnostic signals are often not sufficient to resolve individual formation and post-formation processes. To address such a knowledge gap in a tectonically active and fragmented terrain, samples from mud volcanoes, gas seeps, and springs distributed along structural features onshore and offshore of Taiwan were analyzed for their isotopic compositions of methane, nitrogen, helium, dissolved inorganic carbon, CO2, and water. Our analyses yielded & UDelta;13CH3D and & UDelta;12CH2D2 values ranging between +1.9 & PTSTHOUSND; and +7.8 & PTSTHOUSND; and between +3.0 & PTSTHOUSND; and +19.9 & PTSTHOUSND;, respectively. A portion of the samples were characterized by values that represent the thermodynamic equilibrium at temperatures of 99 & DEG;-260 & DEG;C. These temperature estimates, together with the bulk isotopic compositions and local geothermal gradients (25 & DEG;-30 & DEG;C/km), suggest that methane was formed by thermal maturation of organic matter at depths of 2-9 km below the land surface and channeled upward along faults. Other samples were found to deviate from equilibrium by varying degrees. Considering the geological background, helium isotopic ratios, and nitrogen isotopologue compositions, and methanogens detected at some sites, these gases are either abiotic in origin or a mixture of microbial and thermogenic sources. Regardless of whether the equilibrium of methane isotopologues was reached, few sites hosted by sedimentary formations were characterized by mantle-like helium signatures, indicating decoupled origins and potential degassing of helium from the relic igneous source. Overall, these results suggest the extraction of methane and other gases from multiple depths from strata fragmented by fault displacement in an active orogenic belt.

To ensure the accuracy and reliability of crustal strain measures, sensors require a thorough calibration. In Taiwan, the complicated dynamics of surface and subsurface hydrological processes under semi-tropical climate conditions conjugated with the rough surface topography could have impacted strainmeter deployment, pushing the installation conditions astray from the optimal ones. Here, we analyze the complex response of 11 Gladwin Strain Monitor (GTSM) strainmeter type deployed in north and central Taiwan and we propose a novel calibration methodology which relies on waveform modeling of Earth and ocean tidal strain-related deformations. The approach is completely data-driven, starting from a simple calibration framework and progressively adding complexity in the model depending on the quality of the data. However, we show that a simple quasi-isotropic model (three calibration factors) is generally suitable to resolve the orientation and calibration of 8 instruments out of 11. We also highlight the difficulty of clearly defining the behavior of instruments that are highly affected by hydrological forcing.

A widespread episode of intraplate volcanism followed the cessation of sea-floor spreading in the South China Basin approximately 32-17 Ma BP), affecting large parts of southern China and Indochina, and penetrating oceanic basement and stranded microcontinent fragments. Geochemical data for post-spreading seamount and island lavas define suites of quartz tholeiite, olivine tholeiite, alkali olivine basalt and nephelinite, characterised by OIB-type incompatible-element distributions. High-K alkalic lavas show extreme enrichment in large-ion lithophile and high-field-strength elements relative to N-MORB. Sr-87/Sr-86 and Nd-143/Nd-144 ratios are depleted relative to bulk Earth values and partially overlap with Central Indian Ridge MORB and associated OIB. In contrast, Pb-208/Pb-204 and Pb-207/Pb-204 ratios are variable and surprisingly radiogenic for given MORB-like Pb-206/Pb-204. The isotopic and trace-element systematics confirm source heterogeneity but appear to be decoupled, implying complex mantle enrichment histories. At least two heterogeneous source components are required: a depleted but "contaminated" Indian Ocean MORB type, and an EM-2 reservoir whose isotopic composition corresponds to continent-derived sediment. Dupal-like Pb isotopic compositions (DELTA-7/4Pb=2-13, DELTA-8/4Pb=45-73) are shared by intraplate basalts from Hainan Island, the Penghu Islands, northern Taiwan and post-collision arc basalts from the Philippines. It is proposed these reflect endogenous mantle processes related to disaggregation of the south China margin rather than a northward extension of the southern hemisphere Dupal anomaly.

Light and brassinosteroid (BR) antagonistically regulate the developmental switch from etiolation in the dark to photomorphogenesis in the light in plants. Here, we identify GATA2 as a key transcriptional regulator that mediates the crosstalk between BR- and light-signaling pathways. Overexpression of GATA2 causes constitutive photomorphogenesis in the dark, whereas suppression of GATA2 reduces photomorphogenesis caused by light, BR deficiency, or the constitutive photomorphogenesis mutant cop1. Genome profiling and chromatin immunoprecipitation experiments show that GATA2 directly regulates genes that respond to both light and BR. BR represses GATA2 transcription through the BR-activated transcription factor BZR1, whereas light causes accumulation of GATA2 protein and feedback inhibition of GATA2 transcription. Dark-induced proteasomal degradation of GATA2 is dependent on the COP1 E3 ubiquitin ligase, and COP1 can ubiquitinate GATA2 in vitro. This study illustrates a molecular framework for antagonistic regulation of gene expression and seedling photomorphogenesis by BR and light.

The search for new candidate semiconductors with direct band gaps of similar to 1.4 eV has attracted significant attention, especially among the two-dimensional (2D) materials, which have become potential candidates for next-generation optoelectronics. Herein, we systematically studied 2D Bx/2Nx/2C1-x (0 < x < 1) compounds in particular focus on the four stoichiometric Bx/2Nx/2C1-x (x = 2/3, 1/2, 2/5 and 1/3) using a recently developed global optimization method (CALYPSO) in conjunction with density functional theory. Furthermore, we examine more stoichiometries by the cluster expansion technique based on a hexagonal lattice. The results reveal that all monolayer Bx/2Nx/2C1-x stoichiometries adopt a planar honeycomb character and are dynamically stable. Remarkably, electronic structural calculations show that most of Bx/2Nx/2C1-x phases possess direct band gaps within the optical range, thereby they can potentially be used in high-efficiency conversion of solar energy to electric power, as well as in p-n junction photovoltaic modules. The present results also show that the band gaps of Bx/2Nx/2C1-x can be widely tuned within the optical range by changing the concentration of carbon, thus allowing the fast development of band gap engineered materials in optoelectronics. These new findings may enable new approaches to the design of microelectronic devices.

A new allotrope of nitrogen in which the atoms are connected to form a novel N-6 molecule is predicted to exist at ambient conditions. The N-6 molecule is a charge-transfer complex with an open-chain structure containing both single and triple bonds. The charge transfer induces ionic characteristics in the intermolecular interactions and leads to a much higher cohesive energy for the predicted crystal compared to solid N-2. The N-6 solid is also more stable than a previously reported polymeric solid of nitrogen. Because of the kinetic stability of the molecules and strong intermolecular interactions, the N-6 crystal is shown by metadynamics simulations to be dynamically stable around room temperature and to only dissociate to N-2 molecules above 700 K. The N-6 crystal can likely be synthesized under high-pressure high-temperature conditions, and the considerable metastability may allow for an ambient pressure recovery of the crystal. Because of the large energy difference between the single and triple bonds, the dissociation of the N-6 crystal is expected to release a large amount of energy, placing it among the most efficient energy materials known today.

Using global structure searches, We have explored the structural, stability of CaB3N3, a compound analogous to CaC6, under pressure. There are two high-pressure phases with space groups R3c and Amm2 that were found to be stable between 29 and 42 GPa, and above 42 GPa, respectively. The two phases show different structural frameworks, analogous to graphitic CaC6. Phonon calculations confirm that both structures are also dynamically stable at high pressures. The electronic Structure calculations show that the R3c phase is a semiconductor With a band gap of 2.21 eV and that the Amm2 phase is a semimetal. These findings help advance our understanding of the Ca-B-N ternary system.

Recent hydrodynamic simulations and observations of radio jets have shown that the surrounding environment has a large effect on their resulting morphology. To investigate this, we use a sample of 50 Extended Radio Active Galactic Nuclei (ERAGN) detected in the Observations of Redshift Evolution in Large-Scale Environments survey. These sources are all successfully cross-identified to galaxies within a redshift range of 0.55 <= z <= 1.35, either through spectroscopic redshifts or accurate photometric redshifts. We find that ERAGN are more compact in high-density environments than those in low-density environments at a significance level of 4.5 sigma. Among a series of internal properties under our scrutiny, only the radio power demonstrates a positive correlation with their spatial extent. After removing the possible radio power effect, the difference of size in low- and high-density environments persists. In the global environment analyses, the majority (86%) of high-density ERAGN reside in the cluster/group environment. In addition, ERAGN in the cluster/group central regions are preferentially compact with a small scatter in size, compared to those in the cluster/group intermediate regions and fields. In conclusion, our data appear to support the interpretation that the dense intracluster gas in the central regions of galaxy clusters plays a major role in confining the spatial extent of radio jets.

Solar-induced chlorophyll fluorescence (SIF) shows enormous promise as a proxy for photosynthesis and as a tool for modeling variability in gross primary productivity and net biosphere exchange (NBE). In this study, we explore the skill of SIF and other vegetation indicators in predicting variability in global atmospheric CO2 observations, and thus global variability in NBE. We do so using a 4-year record of CO2 observations from NASA's Orbiting Carbon Observatory 2 satellite and using a geostatistical inverse model. We find that existing SIF products closely correlate with space-time variability in atmospheric CO2 observations, particularly in the extratropics. In the extratropics, all SIF products exhibit greater skill in explaining variability in atmospheric CO2 observations compared to an ensemble of process-based CO2 flux models and other vegetation indicators. With that said, other vegetation indicators, when multiplied by photosynthetically active radiation, yield similar results as SIF and may therefore be an effective structural SIF proxy at regional to global spatial scales. Furthermore, we find that using SIF as a predictor variable in the geostatistical inverse model shifts the seasonal cycle of estimated NBE and yields an earlier end to the growing season relative to other vegetation indicators. These results highlight how SIF can help constrain global-scale variability in NBE.

Defining the age of the Moon has proven to be an elusive task because it requires reliably dating lunar samples using radiometric isotopic systems that record fractionation of parent and daughter elements during events that are petrologically associated with planet formation. Crystallization of the magma ocean is the only event that unambiguously meets this criterion because it probably occurred within tens of millions of years of Moon formation. There are three dateable crystallization products of the magma ocean: mafic mantle cumulates, felsic crustal cumulates, and latestage crystallization products known as urKREEP (uniform residuum K, rare earth elements, and P). Although ages for these materials in the literature span 200 million years, there is a preponderance of reliable ages around 4.35 billion years recorded in all three lunar rock types. This age is also observed in many secondary crustal rocks, indicating that they were produced contemporaneously (within uncertainty of the ages), possibly during crystallization and overturn of the magma ocean.