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Mangroves are critical blue carbon ecosystems. Measurements of methane (CH4) emissions from mangrove tree stems have the potential to reduce uncertainty in the capacity of carbon sequestration. This study is the first to simultaneously measure CH4 fluxes from both stems and soils throughout tidal cycles. We quantified carbon dioxide (CO2) and CH4 fluxes from mangrove tree stems of Avicennia marina and Kandelia obovata, which have distinct root structures, during tidal cycles. Tree stems of both species served as net CO2 and CH4 sources. Compared to fluxes in the soils, the mangrove tree stems exhibited remarkably lower CH4 fluxes but no difference in CO2 fluxes. The stems of A. marina exhibited an increasing trend in CO2 flux from low to high tides. However, CH4 fluxes showed high temporal variability, with the stems of A. marina functioning as a CH4 sink before tidal inundation and becoming a source after ebbing. In contrast, the stems of K. obovata showed no consistent pattern in the CO2 or CH4 fluxes. Based on our findings, the stem CH4 fluxes in A. marina may vary by up to 1200 % when considering tidal influence, compared to when tidal influence is ignored. Therefore, sampling only during low tides might underestimate stem CO2 and CH4 fluxes on a diurnal scale. This study highlights the necessity of considering tidal influence and species when quantifying greenhouse gas (GHG) fluxes from mangrove tree stems. Further study is needed to explore the underlying mechanisms driving the observed flux variations and improve the understanding of GHG dynamics in mangrove ecosystems.

The Okmok volcanic eruption in Alaska has recently been discovered and is precisely dated to have occurred in 43 BCE. Some Chinese climate records of 43–33 BCE have been found in historical documents that provide descriptions of observed environmental abnormities that appear to be consistent with the anticipated changes due to volcanic climate forcing. In this paper, we provide a full translation with discussions of the Chinese climate records that may be related to the Okmok eruption. We have converted ancient Chinese calendar dates to modern Gregorian dates and provided the latitudes and longitudes of the geographical locations mentioned in the records. Relevant climate information in similar areas of China in the decades after the 1783 Laki eruption is also briefly summarized for comparison. We believe the detailed information contained in these records will be useful for further research on the climate impact of volcanic eruptions.

As a typical microdroplet, double emulsion droplet, has received much attention and been widely used in recent years. For a simplified double-cross-shaped microchannel, the process of preparing double emulsion droplets is numerically simulated in this paper. The mechanism of droplet forming was analyzed, and the effects of the angles of the inner-, middle-, and outer-phase channels of the microchip, length of the focusing hole, and expansion angle on the process and quality of the double emulsion droplet formation were investigated. The variation in angles between each inlet channel affects the droplet area; the change in expansion angle affects the flow pattern of droplets; the change in each geometric parameter affects the monodispersity of droplets. The droplet area is fitted to the microchannel geometric parameters and the functional expressions that represent their relationship are derived. The work in this paper provides a reference for the practical production and research of double emulsion droplets.

BackgroundBoth elevated and low resting heart rates are associated with atrial fibrillation (AF), suggesting a U-shaped relationship. However, evidence for a U-shaped causal association between genetically-determined resting heart rate and incident AF is limited. We investigated potential directional changes of the causal association between genetically-determined resting heart rate and incident AF.Method and resultsSeven cohorts of the AFGen consortium contributed data to this meta-analysis. All participants were of European ancestry with known AF status, genotype information, and a heart rate measurement from a baseline electrocardiogram (ECG). Three strata of instrumental variable-free resting heart rate were used to assess possible non-linear associations between genetically-determined resting heart rate and the logarithm of the incident AF hazard rate: 75 beats per minute (bpm). Mendelian randomization analyses using a weighted resting heart rate polygenic risk score were performed for each stratum. We studied 38,981 individuals (mean age 59±10 years, 54% women) with a mean resting heart rate of 67±11 bpm. During a mean follow-up of 13±5 years, 4,779 (12%) individuals developed AF. A U-shaped association between the resting heart rate and the incident AF-hazard ratio was observed. Genetically-determined resting heart rate was inversely associated with incident AF for instrumental variable-free resting heart rates below 65 bpm (hazard ratio for genetically-determined resting heart rate, 0.96; 95% confidence interval, 0.94-0.99; p = 0.01). Genetically-determined resting heart rate was not associated with incident AF in the other two strata.ConclusionsFor resting heart rates below 65 bpm, our results support an inverse causal association between genetically-determined resting heart rate and incident AF.

We investigate the electronic structure of LaCoO_{3} across the gradual spin-state and insulator-to-metal transitions using bulk-sensitive hard x-ray photoelectron and soft x-ray absorption spectroscopies. The spectra exhibit strong variations with temperature. The energy gap is reduced by about 0.6 eV in going from 80 to 650 K but the near Fermi level intensity remains small, classifying LaCoO_{3} as a bad metal even in the metallic phase. We are able to explain the spectra in terms of incoherent sums of low-spin and high-spin Co^{3+} spectra. We also find that the energy parameters for the two Co sites are very different, revealing that paramagnetic LaCoO_{3} is a highly inhomogeneous system with local lattice relaxations that are spin-state-specific. This, in turn, provides a natural explanation for the much-debated temperature dependence of the activation energy for the transitions.

Abstract This investigation reports on anisotropy in the magnetic interaction, lattice-orbital coupling and degree of phonon softening in single crystal Ni3TeO6 (NTO) using temperature- and polarization-dependent X-ray absorption spectroscopic techniques. The magnetic field-cooled and zero-field-cooled measurements and temperature-dependent Ni L 3,2-edge X-ray magnetic circular dichroism spectra of NTO reveal a weak Ni-Ni ferromagnetic interaction close to ~60 K (T SO: temperature of the onset of spin ordering) with a net alignment of Ni spins (the uncompensated components of the Ni moments) along the crystallographic c-axis, which is absent from the ab-plane. Below the Néel temperature, T N~ 52 K, NTO is stable in the antiferromagnetic state with its spin axis parallel to the c-axis. The Ni L 3,2-edge X-ray linear dichroism results indicate that above T SO, the Ni 3d e g electrons preferentially occupy the out-of-plane 3d 3z 2 −r 2 orbitals and switch to the in-plane 3d x 2 −y 2 orbitals below T SO. The inherent distortion of the NiO6 octahedra and anisotropic nearest-neighbor Ni-O bond lengths between the c-axis and the ab-plane of NTO, followed by anomalous Debye-Waller factors and orbital-lattice in conjunction with spin-phonon couplings, stabilize the occupied out-of-plane (3d 3z 2 −r 2) and in-plane (3d x 2 −y 2) Ni e g orbitals above and below T SO, respectively.

Abstract The local electronic and atomic structures of the high-quality single crystal of SrFeO3-δ (δ~0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of anisotropic resistivity in the ab-plane and along the c-axis close to the region of thermal hysteresis (near temperature for susceptibility maximum, Tm~78 K). All experiments herein were conducted during warming and cooling processes. The Fe L 3,2-edge X-ray linear dichroism results show that during cooling from room temperature to below the transition temperature, the unoccupied Fe 3d e g states remain in persistently out-of-plane 3d 3z 2 -r 2 orbitals. In contrast, in the warming process below the transition temperature, they change from 3d 3z 2 -r 2 to in-plane 3d x 2 -y 2 orbitals. The nearest-neighbor (NN) Fe-O bond lengths also exhibit anisotropic behavior in the ab-plane and along the c-axis below Tm. The anisotropic NN Fe-O bond lengths and Debye-Waller factors stabilize the in-plane Fe 3d x 2 -y 2 and out-of-plane 3d 3z 2 -r 2 orbitals during warming and cooling, respectively. Additionally, a VB-PES study further confirms that a relative band gap opens at low temperature in both the ab-plane and along the c-axis, providing the clear evidence of the charge-density-wave nature of SrFeO3-δ (δ~0.19) single crystal.

Herein we show that nonresonant inelastic x-ray scattering involving an s core level is a powerful spectroscopic method to characterize the excited states of transition metal compounds. The spherical charge distribution of the s core hole allows the orientational dependence of the intensities of the various spectral features to produce a spatial charge image of the associated multiplet states in a straightforward manner, thereby facilitating the identification of their orbital character. In addition, the s core hole does not add an extra orbital angular momentum component to the multiplet structure so that the well-established Sugano-Tanabe-Kamimura diagrams can be used for the analysis of the spectra. For α-MnS we observe the spherical charge density corresponding to its high-spin 3d^{5} (^{6}A_{1}) ground state configuration and we were able to selectively image its excited states and identify them as t_{2g} (^{5}T_{2}) and e_{g} (^{5}E) with an energy splitting 10Dq of 0.78 eV.

Summary: Background: Increased blood pressure is the biggest contributor to the global burden of disease and mortality. Data suggest that less than half of the population with hypertension is aware of it. May Measurement Month was initiated to raise awareness of the importance of blood pressure and as a pragmatic interim solution to the shortfall in screening programmes. Methods: This cross-sectional survey included volunteer adults (≥18 years) who ideally had not had their blood pressures measured in the past year. Each participant had their blood pressure measured three times and received a a questionnaire about demographic, lifestyle, and environmental factors. The primary objective was to raise awareness of blood pressure, measured by number of countries involved, number of people screened, and number of people who have untreated or inadequately treated hypertension (defined as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg, or both, or on the basis of receiving antihypertensive medication). Multiple imputation was used to estimate the mean of the second and third blood pressure readings if these were not recorded. Measures of association were analysed using linear mixed models. Findings: Data were collected from 1 201 570 individuals in 80 countries. After imputation, of the 1 128 635 individuals for whom a mean of the second and third readings was available, 393 924 (34·9%) individuals had hypertension. 153 905 (17·3%) of 888 616 individuals who were not receiving antihypertensive treatment were hypertensive, and 105 456 (46·3%) of the 227 721 individuals receiving treatment did not have controlled blood pressure. Significant differences in adjusted blood pressures and hypertension prevalence were apparent between regions. Adjusted blood pressure was higher in association with antihypertensive medication, diabetes, cerebrovascular disease, smoking, and alcohol consumption. Blood pressure was higher when measured on the right arm than on the left arm, and blood pressure was highest on Saturdays. Interpretation: Inexpensive global screening of blood pressure is achievable using volunteers and convenience sampling. Pending the set-up of systematic surveillance systems worldwide, MMM will be repeated annually to raise awareness of blood pressure. Funding: International Society of Hypertension, Centers for Disease Control and Prevention, Servier Pharmaceutical Co.

Nitrate export in small subtropical watersheds is rarely observed and the estimation of individual land use nitrate yield from a mixed combination within catchments has scarcely been studied. In this study the nitrate concentrations at 16 nested catchments in the Chi-Chia-Wan watershed in Central Taiwan were measured during 2007–2008. A 3-layer TOPMODEL was applied to estimate daily discharge for ungauged sub-catchments. The observed nitrate concentrations and the simulated discharges were used for nitrate flux estimations through four flux methods. Meanwhile, a new deconvolution computation was developed to resolve the nitrate yield of each land use from within the mixed combinations. The results showed that the observed mean NO3-N concentration in relatively pristine catchments was approximately 0.145 ± 0.103 mg l−1, which is comparable with other forestry catchments around the world. However, the higher rainfall/runoff, substantial N deposition, and other nitrogen sources resulted in significantly higher annual export of approximately 238–1018 kg-N km−2 yr−1. Our deconvolution computation showed that the background yield of natural forestry was ~351 ±62 kg-N km−2 yr−1. On the other hand, the extremely high nitrate yield of active farmland was ~308, 170 ± 19 241 kg-N km−2 yr−1 due to over-fertilization. The deconvolution computation technique is capable of tracing the mixed signals at the outlet back to the nitrate productions from varied land use patterns. It advances the application of river monitoring network. The typical values of nitrate yields can serve as a guideline for land management. Comparing the nitrogen input and output, we found some nitrogen missing in the cycling which may indicate certain removal processes and we therefore suggest further study to be carried out to fully understand nitrogen cycling in subtropics.

We report on our investigation of the electronic structure of Ti_{2}O_{3} using (hard) x-ray photoelectron and soft x-ray absorption spectroscopy. From the distinct satellite structures in the spectra, we have been able to establish unambiguously that the Ti-Ti c-axis dimer in the corundum crystal structure is electronically present and forms an a_{1g}a_{1g} molecular singlet in the low-temperature insulating phase. Upon heating, we observe a considerable spectral weight transfer to lower energies with orbital reconstruction. The insulator-metal transition may be viewed as a transition from a solid of isolated Ti-Ti molecules into a solid of electronically partially broken dimers, where the Ti ions acquire additional hopping in the a-b plane via the e_{g}^{π} channel, the opening of which requires consideration of the multiplet structure of the on-site Coulomb interaction.

Polar catastrophe at the interface of oxide materials with strongly correlated electrons has triggered a flurry of new research activities. The expectations are that the design of such advanced interfaces will become a powerful route to engineer devices with novel functionalities. Here, we investigate the initial stages of growth and the electronic structure of the spintronic Fe_{3}O_{4}/MgO(001) interface. Using soft x-ray absorption spectroscopy, we have discovered that the so-called A-sites are completely missing in the first Fe_{3}O_{4} monolayer. This discovery allows us to develop an unexpected but elegant growth principle in which, during deposition, the Fe atoms are constantly on the move to solve the divergent electrostatic potential problem, thereby ensuring epitaxy and stoichiometry at the same time. This growth principle provides a new perspective for the design of interfaces.