Search

High-Sr/Y granitoids in continental settings are sometimes erroneously regarded as the products derived from partial melting of thickened/delaminated mafic lower curst under relatively higher pressures (>1.5 GPa) in a collisional orogenic setting. In fact, multiple magmatic processes in the trans-crustal magma system, such as recycling of antecrysts, crustal assimilation, and fractional crystallization, can create or modify the primary "adakitic" signature. As a result, the generation of adakitic magmas in continental settings remains controversial from a bulk-rock perspective. Here, we address the origin of adakitic plutonic rocks through geochemical and textural characterization of rock-forming minerals in the pyroxene-bearing Zhuyuan granodiorite, West Qinling, China. The Zhuyuan granodiorite formed in a post-collisional setting and primarily consists of resorbed orthopyroxene, three types of clinopyroxene, amphibole, two types of plagioclases, K-feldspar, biotite, and quartz. Type-1 Cpx has high XMg (70.0–81.7). Type-2 Cpx displays normal zoning and decreasing XMg (80.9 to 71.5) from the core to rim. Type-3 Cpx is reversely zoned, where the rims have higher XMg (75.5–86.9), Ni, Cr, suggesting a recharge event. Orthopyroxene has high-Ni and -Cr contents, as well as high XMg (80.9–82.8), indicative of antecrysts that grew in mafic magma reservoirs. The injection of magmas from different sources is supported by sieve-textured plagioclase and crystal size distributions of non-poikilitic amphibole. Finally, non-sieve textured plagioclase, biotite, K-feldspar, and quartz are late-crystallized phases, indicative of an orthocrystic origin. The melts in equilibrium with these orthocrysts display significantly higher Sr/Y values than the magma batches that crystallized other mafic phases (i.e., amphibole, clinopyroxene, and orthopyroxene). Thus, we propose that the system involved an initial high-Sr/Y melts in equilibrium with the orthocryst assemblage was generated by water-fluxed melting of intermediate to felsic sources. The addition of low Sr/Y non-orthocrysts (e.g., amphibole and pyroxene) and associated melt diluted the original "adakitic signal" in the magma reservoir and drove the bulk composition to more mafic values. Consequently, the Zhuyuan pyroxene-bearing granodiorite represents a mixture of crystals with diverse origins and distinct magma batches of various compositions (from felsic to mafic compositions). Our study emphasizes that the origin of adakitic granitoids cannot be clearly deciphered without geochemical analysis of the constituent minerals. We also suggest that Sr/Y values in plutons should be cautiously used in paleo-crustal thickness estimates in collisional settings because of possible open system scenarios as described here. [ABSTRACT FROM AUTHOR]

The main objective of this study is to put forward effective schemes for alleviating reservoir choke caused by emulsification or Jamin's effect using the dilution method by light crude oil, as well as sharply increased viscosity. In this study, water-in-heavy-oil (W/O) emulsions with varying water fractions were prepared with heavy oil from Bohai Bay, China. Mixtures of W/O emulsions and light crude oil samples (light oil and light heavy oil) with varied dilution ratio (1:9, 2:8, 3:7) are tested, respectively by the electron microscope and by the rheometer. W/O droplets' distribution and viscosity variations are obtained to evaluate the emulsion stability and viscosity reduction effects by dilution. Results show that W/O droplets, size distribution range increases with the increase of water fractions. W/O droplets with larger size tend to be broken first in the dilution process. Light oil could reduce emulsions' viscosity more effectively than light heavy oil. Viscosity reduction mechanisms by dilution could be concluded as the synergistic effects of dissolving heavy components and weakening oil–water film stability. Therefore, light oil is suggested as the optimal one for solving formation plugging. The poor performance of Richardson model is related to the re-emulsification between free water and crude oil favored by light heavy oil, and demulsification favored by light oil. The modified model shows a significant improvement in prediction accuracy, especially for W/O emulsions with large water fractions. This study demonstrates a promising and practical strategy of solving heavy oil well shutdown problems and viscosity increasing by injecting light crude oil in the thermal stimulation. [ABSTRACT FROM AUTHOR]

Background: Multidrug resistance in Enterobacteriaceae including resistance to quinolones is rising worldwide. The development of resistance may lead to the emergence of new transmission mechanisms. In this study, the collection of different E. coli was performed from animals and subjected to subsequent procedures including pulsed-field gel electrophoresis, micro-broth dilution method, polymerase chain reaction. Whole genome sequencing of E. coli C3 was performed to detect the affinity, antimicrobial resistance and major carriers of the isolates. Results: A total of 66 E. coli were isolated and their antibiotic resistance genes, frequency of horizontal transfer and genetic environment of E. coli C3 were determined. The results showed there were both different and same types in PFGE typing, indicating clonal transmission of E. coli among different animals. The detection of antimicrobial resistance and major antibiotic resistance genes and the plasmid transfer results showed that strains from different sources had high levels of resistance to commonly used clinical antibiotics and could be spread horizontally. Whole-genome sequencing discovered a novel ICE mobile element. Conclusion: In summary, the antimicrobial resistance of E. coli in northeast China is a serious issue and there is a risk of antimicrobial resistance transmission. Meanwhile, a novel ICE mobile element appeared in the process of antimicrobial resistance formation. [ABSTRACT FROM AUTHOR]

Huangqi Guizhi Wuwu decoction (HGWD), as a classical formula, has been used for thousands of years in China. In this work, a comprehensive strategy was proposed for characterizing the chemical profile of HGWD based on online two-dimensional hydrophilic interaction and reversed-phase liquid chromatography coupled with hybrid linear ion trap-Orbitrap mass spectrometry (online HILIC × RP-ESI/HRMS/MSn). The compounds in HGWD were first separated by the combined use of an XBridge amide column (150 × 4.6 mm, 3.5 μm) and Accucore C18 column (50 mm × 4.6 mm, 2.6 μm). Modulation with assistant technology, including trap columns and online dilution, was optimized and developed to decrease potential analyte loss and improve the resolution of the system. Subsequently, the accurate mass was determined by high-resolution Orbitrap and MSn fragment data by a hybrid linear ion trap (LTQ). In total, 170 chemical constituents were unambiguously identified or tentatively characterized in both positive and negative ion modes. Our study demonstrated that the proposed online HILIC × RP system coupled to the LTQ-Orbitrap MS platform is an efficient analytical technique for characterizing the chemical profile of multicomponent systems. [ABSTRACT FROM AUTHOR]

Objective The aim is to solve the analysis problems on the accurate determination of micro-trace impurity components in the high-quality development of China’s hydrogen energy industry. Methods For the quality analysis of hydrogen fuel, a gas dilution method based on the principle of critical flow orifices was established. As the major component of the sample to be tested is hydrogen rather than nitrogen, the math module of flow response factor is studied to investigate the influences on the flow of different gases. Results The dilution ratio of this method could achieve over 1∶1 000 with a relative expand uncertainty of better than 1%. The gas reference materials, namely formaldehyde and methane in hydrogen, are prepared in a 10-9 molar fraction level dynamically. The measured repeatability of concentrations of the gas reference materials is no more than 7%. The linear correlation coefficient R~2 of each diluted concentration is more than 0.999. Conclusions The analysis results of formaldehyde in nitrogen and in hydrogen respectively conclude that the math module of flow response factor is reliable, and the accuracy of this gas dilution method will be improved after a correction by flow response factor. [ABSTRACT FROM AUTHOR]

Background and aims : N nutrition index (NNI) diagnosis and N requirement (Nfr) estimation are essential for accurate N management in the fertirrigation system. However, the NNI after straw retention and the relationships between NNI, Nfr, and relative yield (RY) are all not fully understood. Methods: A three years field trial with three straw incorporation methods (without straw (NI), with straw (SI), and straw-derived biochar incorporation (BI)) and five N rates (0, 150, 225, 300, and 375 kg ha−1) was conducted on drip-irrigated maize in northwest China. Soil NO3−-N content (CN), N recovery efficiency (REN), NNI, Nfr, and grain yield under NI, SI, and BI were compared. Later, the mathematical relationships between NNI, Nfr, and RY were defined. Results: Results showed that compared with NI, the N input during the reproductive stage could be reduced under SI and BI to achieve higher grain yield with NNI increased due to an increase in CN. In addition, Nfr was calculated by dividing N accumulation deficit (NAD) by REN, where a significant linear relationship existed between NAD and NNI (NAD = S(1-NNI)), and the slope of the NAD-NNI regression (S) varied quadratically with days after sowing (DAS). NNI and RY were also related in linear plus plateau functions, and the maximum RY was achieved when NNI was 0.88. Conclusions: Based on patterns of variance, three easily accessible independent variables (DAS, REN, and NNI) were used to create and verify Nfr estimating techniques for generating higher yields in maize under NI, SI, and BI. [ABSTRACT FROM AUTHOR]

The influence of urbanization on the frequent winter aerosol pollution events in Northeast China is not fully understood. The Weather Research and Forecasting Model with Chemistry (WRF–Chem) coupled with urban canopy (UC) models was used to simulate the impact of urbanization on an aerosol pollution process in the Central Liaoning city cluster (CLCC), China. To investigate the main mechanisms of urban expansion and UC on the winter atmospheric environment and the atmospheric diffusion capacity (ADC) in the CLCC, three simulation cases were designed using land-use datasets from different periods and different UC schemes. A comparative analysis of the simulation results showed that the land-use change (LU) and both LU and UC (LUUC) effects lead to higher surface temperature and lower relative humidity and wind speed in the CLCC by decreasing surface albedo, increasing sensible heat flux, and increasing surface roughness, with a spatial distribution similar to the distribution of LU. The thermal effect leads to an increase in atmospheric instability, an increase in boundary layer height and diffusion coefficient, and an increase in the ADC. The LU and LUUC effects lead to a significant decrease in near-surface PM2.5 concentrations in the CLCC due to changes in meteorological conditions and ADC within the boundary layer. The reduction in surface PM2.5 concentrations due to the LU effect is stronger at night than during daytime, while the LUUC effect leads to a greater reduction in surface PM2.5 concentrations during the day, mainly due to stronger diffusion and dilution caused by the effect of urban turbulence within different levels caused by the more complex UC scheme. In this study, the LU and LUUC effects result in greater thermal than dynamic effects, and both have a negative impact on surface PM2.5 concentrations, but redistribute pollutants from the lower urban troposphere to higher altitudes. [ABSTRACT FROM AUTHOR]

Plant N concentration (PNC) has been commonly used to guide farmers in assessing maize (Zea mays L.) N status and making in-season N fertilization decisions. However, PNC varies based on the development stage. Therefore, a relationship between biomass and N concentration is needed (i.e., critical N dilution curve; CNDC) to better understand when plants are N deficient. A few CNDCs have been developed and used for plant N status diagnoses but have not been tested in the US Midwest. The objective of this study was to evaluate under highly diverse soil and weather conditions in the US Midwest the performance of CNDCs developed in France and China for assessing maize N status. Maize N rate response trials were conducted across eight US Midwest states over three years. This analysis utilized plant and soil measurements at V9 and VT development stages and final grain yield. Results showed that the French CNDC (y = 34.0x−0.37, where y is critical PNC, and x is aboveground biomass) was better with a 91% N status classification accuracy compared to only 62% with the Chinese CNDC (y = 36.5x−0.48). The N nutrition index (NNI), which is the quotient of the measured PNC and the calculated critical N concentration (Nc) based on the French CNDC was significantly related to soil nitrate-N content (R2 = 0.38–0.56). Relative grain yield on average reached a plateau at NNI values of 1.36 at V9 and 1.21 at VT but for individual sites ranging from 0.80 to 1.41 at V9 and from 0.62 to 1.75 at VT. The NNI threshold values or ranges optimal for crop biomass production may not be optimal for grain yield production. It is concluded that the CNDC developed in France is suitable as a general diagnostic tool for assessing maize N status in US Midwest. However, the threshold values of NNI for diagnosing maize N status and guiding N applications vary significantly across the region, making it challenging to guide specific on-farm N management. More studies are needed to determine how to effectively use CNDC to make in-season N recommendations in the US Midwest. [ABSTRACT FROM AUTHOR]

Background: Serum C-peptide results from various routine methods used in China are highly variable, warranting well-performing methods to serve as an accuracy base to improve the harmonization of C-peptide measurements in China. We developed an accurate isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for serum C-peptide measurement and explored its use in harmonization. Methods: After protein precipitation with ZnSO4 solution, C-peptide was extracted from serum samples by anion-exchange solid-phase extraction and quantified by ID-LC-MS/MS in positive ion mode. The precision and analytical recovery of the ID-LC-MS/MS method were assessed. Seventy-six serum samples were analyzed using the ID-LC-MS/MS method and six routine immunoassays. Ordinary linear regression (OLR) and Bland-Altman (BA) analyses were conducted to evaluate the relationship between the ID-LC-MS/MS method and routine immunoassays. Five serum pool samples assigned using the IDLC-MS/MS method were used to recalibrate the routine assays. OLR and BA analyses were re-conducted after recalibration. Results: The within-run, between-run, and total precision for the ID-LC-MS/MS method at four concentrations were 1.0%-2.1%, 0.6%-1.2%, and 1.3%-2.2%, respectively. The analytical recoveries for the ID-LC-MS/MS method at three concentrations were 100.3%- 100.7%, 100.4%-101.0%, and 99.6%-100.7%. The developed method and the immunoassays were strongly correlated, with all R2 >0.98. The comparability among the immunoassays was substantially improved after recalibration. Conclusions: The performance of the ID-LC-MS/MS method was carefully validated, and this method can be used to improve the harmonization of serum C-peptide measurements in China. [ABSTRACT FROM AUTHOR]

Under the large-scale application of hydrogen energy and the acceleration of utility tunnel construction in China, the hydrogen pipeline would enter the utility tunnel soon. The explosion-prevention strategy is of important to hydrogen transportation in utility tunnel. Thus, a series of comparative studies were carried out in the present study, to explore the high efficiency dilution methods for unexpected hydrogen leak scenarios. (1) Effects of source type and domain extension were further validated based on our previous numerical model. The small-hole model was found to be simple and feasible for pipe release simulation, and has the same high accuracy like the notional nozzle model. The influence of unexpanded domain is acceptable. (2) Investigation of the explosion-prevention strategies was performed based on the finding of the worst leakage case, and hydrogen leaks at the middle of the upwind tunnel with upward leak direction was found to be the worst leakage case for the normal utility tunnel. (3) Compared with the layouts of lateral vents and the single horizontal air distributor, the middle exhaust vent was found to be the optimal airflow controlling strategy. (4) Furtherly, compared to the optimal airflow controlling strategy, closed-inerting was validated to be the most efficient dilution method. In the closed-inerting cases, the peak value of the flammable gas volume which is only ∼40% of the unimproved case appears. After that, the flammable cloud volume decays gradually, while the value increases steadily in the initial unimproved case. No obvious difference was found between the N 2 and CO 2 injection cases. • The hydrogen explosion-prevention strategies in utility tunnel were explored. • The effects of source model and extension domain were clarified. • The worst leakage case of leak location and leak direction was found. • The airflow controlling and closed-inerting methods were studied. [ABSTRACT FROM AUTHOR]

For the in-situ treatment process of landscape waters, ponds, reservoirs and other water bodies, there is a significant deviation between the experiment results and the actual treatment effect due to volume amplification effect. Therefore, this study systematically explored the influence of hydraulic conditions, dosing frequency, dosing intervals of coagulant, and coagulant dilution multiples on the removal efficiency of particulate and organic matter on a large scale to precisely simulate the practical treatment situation. Results showed that dosing intervals and dosing frequency played an important role in the aggregation and settling process of particulate matter by influencing the energy barrier between particles, while hydraulic conditions affected the structure and settling characteristics of flocs. The overall trend of the total organic matter was consistent with that of particulate matter. However, only the freshly formed aluminum hydroxide precipitates had adsorption activity to humic substances. The adsorption could be completed rapidly so that hydraulic conditions had no influence on the aggregation process of humic substances. While during stirring and aging process, humic substances was found to be released due to the polymerization and crystallization of aluminum precipitates. From the results of pilot tests, a treatment strategy was implemented for a reservoir in southern China and the ideal treatment effect was achieved. This study provided theoretical foundation and design guidance for the in-situ coagulation treatment of landscape waters, ponds and reservoirs. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: A number of studies have shown that E -test overestimated the presence of Helicobacter pylori resistance compared to agar dilution. Objective: The purpose of this study was to explore whether E -test could be an alternative for agar dilution to detect the metronidazole susceptibility of H. pylori. Method: E -test and agar dilution were used to assess the susceptibility of H. pylori to metronidazole, clarithromycin, and levofloxacin in 281 clinical isolates obtained from China where the resistance was high. Cohen's kappa analysis, McNemar's test, and essential and categorical agreement analysis were performed for these two methods. Results: Overall, the result of the E -test showed a similar prevalence of resistance rate to all antibiotics compared with agar dilution. The essential agreement of the E -test method and agar dilution in the evaluation susceptibility of H. pylori to clarithromycin and levofloxacin was moderate at 89.0 and 79.7%, respectively, but only 45.9% for metronidazole. The results shown by a categorical agreement (CA) between the E -test and agar dilution were 100% for both clarithromycin and levofloxacin. As for metronidazole, the CA was 98.7%, no major error was identified, and the rate of a very major error was 1.8%. Conclusion: E -test can be an alternative method to detect the metronidazole susceptibility of H. pylori. [ABSTRACT FROM AUTHOR]

The Karst aquifers are usually characterized by high spatial heterogeneity in the humid tropics and subtropics, evidenced by specific landforms features (e.g., heavily fractured outcrops, sinkholes, etc.) and complex subterranean conduit networks. The marked high heterogeneity leads to the temporal–spatial variability of hydrological and hydro-chemical processes, making its environments extremely vulnerable to natural and anthropogenic hazards. The complicated temporal–spatial variability of hydrochemistry in karst systems depends on several underlying factors which influence the hydro-chemical processes. Investigating the factors of the karst water hydrochemistry variability is necessary to understand the hydro-chemical processes and mitigate natural and anthropogenic hazards for ensuring the sustainability of karst water resources. In this paper, an attempt is made to couple geostatistical and geochemical analysis to extract the underlying controlling factors and effective information about the geochemical evolution behave of karst water in Houzhai karst area, southwestern China. Factor analysis was performed to obtain significant statistical relationship of the hydrochemistry variation in the Houzhai karst basin. The ordinary kriging method was applied to the factor scores to investigate the contributions of factors on different regions. The results of the factor analysis indicated four principal factors which explained > 81.678% of the total sample variance: (1) the dilution effect by rainfall; (2) the dissolution effect dominated by calcite; (3) the human agricultural activities effect; (4) the migration of dissolved components under the control of alkaline environments in karst water. It revealed that the dilution effect was more significant (36.579%) than the dissolution effect (22.036%) and human agricultural activities effect (14.596%). These factors made more significant difference of contributions on the karst area in the dry periods than in the rainy periods. The dilution process by rainfall and the dissolution process of carbonate rock had a great influence on the upstream area whereas the human agricultural activities played important roles in the middle-stream area, especially in the dry periods. This integrated approach which combine factor analysis with kriging method is effective in the identification and interpretation of factors related to the variability of hydrochemistry, as well as the contributions of these factors on space and time. [ABSTRACT FROM AUTHOR]

Jasminum sambac is a flower and usually used in food, cosmetics or other chemical industries for its unique flavour characteristics in China. However, molecular sensory technologies have not applied to identify aroma‐active compounds in J sambac concrete. In this study, gas chromatography‐olfactometry (GC‐O), gas chromatography‐mass spectrometry and solvent‐assisted flavour evaporation were applied to isolate the odorants in three Chinese J sambac concrete (E1, E2 and E3) obtained from different companies. A total of forty‐nine, forty‐eight, thirty‐nine odorants were screened by GC‐O with aroma extract dilution analysis in E1, E2 and E3, respectively. The higher flavour dilution (FD) factors were linalool (19 683‐59 049, floral), methyl anthranilate (6561‐19 683, grape‐like) and benzyl acetate (2187‐19 683, floral). Twenty‐two aroma compounds were quantitated by gas chromatography‐flame ionization detection with internal standard, and then their odour activity values were obtained. Linalool, cis‐3‐hexenyl acetate, linalyl acetate, eugenol and methyl salicylate contributed greatly to the aroma of J sambac concretes. The aroma recombination model was established by mixing twenty‐two key odorants based on their measured concentrations, and the result revealed that the overall aroma profile was similar to that of the original sample. These results proved basic data for improvement of the national standard of jasmine concrete. [ABSTRACT FROM AUTHOR]

The One-Child Policy dramatically changed the Chinese family structure, and the literature indicates that only children may have an advantage in terms of family resource dilution. Moreover, as Chinese families traditionally prioritize investing in sons, only daughters are found to have been empowered by the policy because they did not need to compete with their brothers for parental investment. However, the literature is limited to only teenage children when they were still living in their parents' homes. It is unclear whether—when the generation of only children grew up and married—their family structure differed from that of children with siblings and whether married only daughters retained more family resources from their parents. Based on the data analysis of a 2016 survey, "Study of Youths in 12 Cities of Mainland China," including a sample of 1,007 fathers and 2,168 mothers born between 1975 and 1985, this study explores the empowerment of married only daughters, employing the theory of family resource dilution in expanded Chinese families. Using educational investment in children as an example, and with random intercept models, this study presents empirical evidence that the dilution of family resources in Chinese expanded families still benefits males and patrilineal practices. Thus, this study demonstrates that Chinese families still tend to sacrifice the interests of married daughters to ensure support for their adult sons. However, it also illustrates that married only daughters could still connect to their parents' resources, giving them a relatively dominant position for decision-making regarding the family's educational expenditure on her own children. Thus, this study extends our understanding of the family resource dilution theory to Chinese expanded families, underscoring the need for further research on Chinese only children after they marry and form families of their own. [ABSTRACT FROM AUTHOR]

The positioning performance of BeiDou Navigation Satellite System （BDS） /Quasi⁃Zenith Satel⁃ lite System （QZSS） and its combined systems in China, Japan and their peripheral areas is evaluated and analyzed by using the observation data of the multi⁃GNSS experiment (MGEX) from the number of visible satellites, dilution of precision, the multipath effect, the signal⁃to⁃noise ratio (SNR), the static precise point positioning （PPP） and kinematic PPP . The results show that the combination of QZSS and BDS system can increase the number of satellites and provide better spatial geometry distribution, thus ensuring the accu⁃ racy, reliability and availability of positioning. Because the constellation structure of QZSS satellite is similar to that of BDS satellite, its multipath effect is consistent with that of BDS satellite. The SNR of MEO(medi⁃ um earth orbit) satellite is 2⁃3 dBHz higher than that of inclined geosynchronous orbit(IGSO) satellite at the same altitude angle. For static and kinematic PPP, the improvement of BDS+QZSS combination is more obvious than that of BDS single system at low altitude angle when the altitude angle is larger (40°). The im⁃ provement rate of E, N and U directions static PPP can reach more than 20%， where kinematic PPP can reach more than 30%. QZSS plays a complementary and enhanced role in BDS positioning in Japan, China and surrounding areas. In the complex environment (such as city, building intensive area, mountain area, et al.) where the signal is easy to block, it will have better application value. [ABSTRACT FROM AUTHOR]

Tissue distributions and body‐size dependent and species‐specific bioaccumulation of 12 organic ultraviolet absorbents (UVAs) were investigated in 9 species of wildlife freshwater fish from the Pearl River catchment, South China. The concentrations of the 12 UVAs were from 109 to 2320 ng/g lipid weight in the fish tissue samples. The UVAs 2‐hydroxy‐4‐methoxybenzophenone (BP‐3), octocrylene (OCR), UV531, and 5 benzotriazole UV stabilizers (UVP, UV329, UV234, UV328, and UV327) were detected in more than half of the fish tissue samples. The UVA UV531 showed an obvious potential for bioaccumulation in the wild freshwater fish, with an estimated bioaccumulation factor (log BAF) and a biota–sediment accumulation factor (BSAF) of 4.54 ± 0.55 and 4.88 ± 6.78, respectively. Generally, liver (989 ± 464 ng/g lipid wt) contained the highest level of UVAs, followed in decreasing order by belly fat (599 ± 318 ng/g lipid wt), swimming bladder (494 ± 282 ng/g lipid wt), dorsal muscle (470 ± 240 ng/g lipid wt), and egg (442 ± 238 ng/g lipid wt). The bioaccumulation of UVAs in the freshwater wild fish was species specific and compound dependent. Bottom‐dwelling detritus‐ingesting omnivorous fish contained obviously higher UVA concentrations, suggesting that detritus/sediment ingestion is a significant pathway for exposure of the wild freshwater fish to the UVAs. The UVAs UV531 and BP‐3 demonstrated a potential for growth dilution. Metabolism might play a significant role in elimination of the UVAs in the fish tissues, with the highest rate of metabolism in the liver. The UVAs did not demonstrate obvious trophic magnification in the freshwater ecosystem of the Pearl River catchment. More research is warranted to elucidate maternal transfer of the UVAs. Environ Toxicol Chem 2020;39:343–351. © 2019 SETAC [ABSTRACT FROM AUTHOR]

Oilfield brines are a significant alternative lithium resource to meet the global demand in the next decades. However, their metallogenic characteristics and mechanism remain unclear. To constrain the source and enrichment process, this study presents chemical and multi-isotope data for oilfield brines from the Middle Eocene to Lower Oligocene Qianjiang Formation of the Jianghan Basin, central China. These formation water samples collected from 159 oil wells have salinities of 47–355 g/L and lithium contents of 5.36–150.00 mg/L. The good linear relationship between δD and δ18O values indicates that the salinities are achieved by dilution of the primary brine by meteoric water. Waters from the lower of the Qianjiang Formation have higher δD and δ18O values and 87Sr/86Sr ratios than those from the upper, in conjunction with the low correlation between the δD and δ18O value and the salinity and between the Sr content and the 87Sr/86Sr ratio, indicating the impact of associated water-rock interactions. Moreover, contributions from diagenetic processes of dolomitization, dissolution of evaporites and albitization are also indicated by the high Cl/Br mass and Na/Cl molar ratios and the Ca excess and Na deficit. Chemical geothermometers give reservoir temperature values of 118 °C and 138 °C on average for the oilfield brines from the upper and lower formation, respectively. The binary linear relationships between Li contents and TDS values and Br contents imply specific enrichment processes in addition to evapo-concentration. Variations in δ7Li values (+10.6‰–+21.3%) and 87Sr/86Sr ratios (0.709479–0.711516) were used to trace the process of Li enrichment in oilfield brines. The lower δ7Li values with more enriched Li in comparison to Na indicate a significant lithium input from clastic host rocks, which is also confirmed by the fact that more radiogenic waters have relatively lower δ7Li values. Overall, these results suggest that Li enrichment in the Qianjiang oilfield brines was generated by the interaction of Li-bearing minerals in the clastic host rocks with water formed by original evaporitic brines diluted by meteoric water. This work represents a significant role of lithium and strontium isotopic systematics in elucidating the Li origins of deep-seated oilfield brines in continental petroliferous basins. [Display omitted] • Halite dissolution contributes to the salinity of oilfield brines. • H, O and Sr isotopes suggest meteoric invasion and water-rock reaction. • Lithium isotope signature indicates a water-rock interaction trend. • Interaction with reservoir host rocks results in lithium enrichment in brines. [ABSTRACT FROM AUTHOR]

China is the largest producer of sweetpotato in the world. The unreasonable application of fertilizer in actual production has led to the imbalance of sweetpotato source and sink. Reasonable use of fertilizer requires proper proportion of nitrogen (N) and potassium (K) to balance nutrients of shoots and roots to achieve optimal growth. The changes of critical N dilution curves of shoot, root and whole plant of sweetpotato were analyzed according to different K levels to quantify the effect of K levels on critical N concentration. In this study, two sweetpotato varieties (Yan25 and Shang19), two K application levels (K0 and K1) and five N application levels (N0-N4) were used to construct a dilution model for the critical N concentration of sweetpotato shoot, root and whole plant. Xinxiang was used for model validation. The critical N concentration dilution model of sweetpotato shoot is as follows: K0: Nc = 4.391DM−0.504; K1: Nc = 4.572DM−0.418. The critical N concentration dilution model of sweetpotato root is as follows: K0: Nc = 0.93DM−0.24; K1: Nc = 1.06DM−0.205. The critical N concentration dilution model of sweetpotato whole plant is as follows: K0: Nc = 3.44DM−0.415; K1: Nc = 3.742DM−0.348. Application of K fertilizer increased the dilution curve of critical N concentration in all parts of sweetpotato. At the K0 level, the optimal N application rate of Yan25 and Shang19 was 120 kg N ha−1 (N2), and at the K1 level, the optimal N application rate was 180 kg N ha−1 (N3). We found that (i) K has greater ability to improve the N absorption of sweetpotato than its ability to increase the dry matter. Differences in critical N curves between different K levels could quantify the effect of K on critical N concentration of sweetpotato. (ii) Under low N conditions, applying K fertilizer will make N more deficient; Under high N conditions, applying K fertilizer will make N suitable and inhibit overgrowth of shoots. (iii) The critical N concentration dilution model based on the whole plant is more suitable for root crops such as sweetpotato and shows high practicability. This study identified changes in the critical N concentration of sweetpotato under different K application levels. ● Construction of critical nitrogen concentration model for different parts of sweetpotato. ● Potassium increased critical nitrogen concentration model of sweetpotato. ● NNI for diagnosis of nitrogen concentration in sweet potato under different potassium fertilizer models. ● The effect of K levels on critical N concentration of sweetpotato was quantified. [ABSTRACT FROM AUTHOR]

GPS tracking has been increasingly used for wildlife studies in recent decades, but its performance has not been fully assessed, especially for newly developed lightweight transmitters. We assessed the performance of eight GPS transmitters developed in China by attaching them to Crested Ibises Nipponia nippon confined to two acclimation cages mimicking real habitats. We calculated the distance between GPS locations and the centroid of the cages as the positioning error, and used the 95% (95th percentile) positioning errors to define the accuracy. The positioning success averaged 92.0%, which is much higher than that of previous studies. Locations were not evenly distributed by Location Class (LC), with the LC A and B locations accounting for 88.7%. The observed 95% positioning error in the locations of LC A (9-39 m) and B (11-41 m) was quite accurate, while up to 6.9-8.8% of poor-quality locations were detected in LC C and D with >100mor even >1;000mpositioning error. Positioning success and accuracy were different between the test sites, probably due to the difference in vegetation structure. Thus, we argue that the tested transmitters could provide a large proportion of high-quality data for fine-scale studies, and a number of poor- quality locations that need attention. We suggest that the HPOD (horizontal dilution of precision) or PDOP (positional dilution of precision) be reported instead of the LC as a measurement of location accuracy for each location to ensure identification and filtering of implausible locations. [ABSTRACT FROM AUTHOR]

Biomass-burning emissions are a significant source of primary organic aerosol (POA). Volatility is one of the most important physical properties of organic aerosol (OA). Dilution and thermodenuder (TD) measurements were used to investigate the volatility of POA from household crop waste combustion in China. Between 10% and 30% of the POA desorbed when diluted from 20:1 to 120:1, while 10%–40% of POA evaporated in the TD when heated to 150 °C. Thus, a considerable proportion of the POA emissions were volatile. A dynamic mass transfer model was applied to derived volatility distributions of POA based on TD data. A best fit volatility distributions for POA and associated mass accommodation coefficients (α), and the enthalpy of vaporization (ΔH vap) were presented. The emissions factors and volatility distribution of POA emission from household crop waste combustion in this study can be used to improve emission inventories and simulate gas-particle partitioning of organic aerosol in chemical transport models. [Display omitted] • Volatility of primary organic aerosol from biomass combustion was investigated. • Primary organic aerosol emissions were affected by dilution ratio. • 10%–40% of primary organic aerosol evaporated when heated. • A considerable proportion of primary organic aerosol were volatile. • A best fit volatility distributions for primary organic aerosol were determined. [ABSTRACT FROM AUTHOR]

Formation waters from the Huanghekou Sag, offshore Bohai Bay Basin, exhibited two depth zones with elevated total dissolved solid (TDS) composition. The shallow diagenetic zone at a depth of ∼1200–2000 m (∼45–70 °C) and the deep diagenetic zone at a depth of ∼3000–4000 m (∼100–130 °C) have TDS concentrations exceeding 70,000 mg/L, while the depth interval in between the two zones has TDS concentrations lower than 35,000 mg/L. Isometric log-ratio interpretations of the reconstructed formation water compositions, crude oil compositions, stable hydrogen and oxygen isotopes, light microscopy and clay mineral analysis were used to interpret the origins of the two diagenetic depth zones. Formation waters within each stratigraphic unit were dominantly composed of Na–K–Cl type. Processes affecting the deep diagenetic zone were attributed to (1) the dissolution of halite, albite and albitization, which predominantly caused the TDS enrichment, and (2) the dilution of TDS caused by the inter-layer H 2 O released from the transformation of smectite to illite (salinity reversal at depths > ∼3500 m). In comparison, the enrichment in TDS in the shallow diagenetic zone was attributed to hydrocarbon biodegradation, which consumed free water. The crude oil composition indicates severe hydrocarbon biodegradation. Biodegradation of low-molecular-weight organic carbons such as hexadecane (through methanogenesis) and benzene (through microbial sulfate reduction) could consume sufficient H 2 O to enrich TDS to the observed levels. At the same time, relatively constant Na/Cl and Ca/Cl ratios versus TDS can be explained by water consumption as well. This work could serve as a reference for the interpretation of two diagenetic zones characterised by distinct TDS enrichments in other hydrocarbon-bearing sedimentary basins. • A deep (3000–4000 m) and a shallow (1200–2000 m) zones exhibited elevated TDS. • Dissolution of evaporites and albitization caused TDS enrichment in the deep zone. • Smectite-illite transition caused reverse salinity decrease in the deep zone. • Hydrocarbon biodegradation caused TDS enrichment in the shallow zone. [ABSTRACT FROM AUTHOR]

• A hybrid 3He Joule-Thomson (JT) cryocooler is designed for precooling the space closed-cycle dilution refrigerator. • With a power consumption of 320 W, the 3He JT cryocooler attains a cooling power of 3.75 mW at 1.54 K with temperature fluctuation lower than ± 0.02 K. Space sub-Kelvin refrigeration technology is an indispensable part of many deep space exploration missions. The dilution refrigerator (DR) is one of the sub-Kelvin refrigerators used in space missions. The space DR requires a closed-cycle design for a longer service life. The 3He Joule-Thomson (JT) cryocooler is an excellent choice among the space mechanical cryocoolers for precooling the space closed-cycle DR (CCDR) because it can provide a stable, vibration-free precooling environment. In this paper, the required cooling capacity of the CCDR's final precooling stage is calculated. The design goal of the 3He JT cryocooler is to obtain 3.6 mW of cooling power at or below 1.7 K. A third-stage counter-flow heat exchanger (CFHX3) is designed for the 3He JT cryocooler with an actual heat exchange efficiency higher than 99 %. A four-stage JT compression system consisting of two oil-free linear compressors is developed based on space compressors verified by many space missions of China. The JT expansion impedance consists of two orifices with diameters of 27 μm and 26 μm in series. Then, experiments are conducted on the coordination of the CFHX3, the JT expansion impedance, and the JT compression system. Hence, a hybrid 3He JT cryocooler is successfully designed, fabricated, and tested for the CCDR and obtains a no-load temperature of 1.40 K with a power consumption of 277 W. Furthermore, with a power consumption of 320 W, the 3He JT cryocooler attains a cooling power of 3.75 mW at 1.54 K with temperature fluctuation lower than ±0.02 K. [ABSTRACT FROM AUTHOR]

Background: Proteeae isolates displaying multidrug-resistance (MDR) are the second most common causes of hospital-associated infections. The aim of this study was to screen class 1-3 integrons and plasmid-mediated quinolone resistance (PMQR) genes in Proteeae isolates from the First Affiliated Hospital of the Wenzhou Medical University. Materials and Methods: 176 Proteeae isolates were collected from clinical specimens of inpatients between January 2011 and December 2013. Susceptibility testing was determined by the agar dilution method. Class 1-3 integrons and PMQR genes were amplified by polymerase chain reaction, and the variable regions of integrons were determined by restriction fragment length polymorphisms. Results: 68.2% Proteeae isolates exhibited MDR phenotypes: 46.6 and 10.8% Proteeae isolates were positive for intI1 and intI2, respectively. The resistance rate of integron-positive isolates to aminoglycosides, fluoroquinolones, and trimethoprim/sulfamethoxazole was significantly higher than integron-negative isolates. Sequence analysis revealed that dfrA1-sat2-aadA1, dfrA1-catB2-sat2-aadA1, and sat2-aadA1 were first detected in Morganella morganii strains isolated from China. PMQR was determined by qnrD in 40 strains (22.7%). Conclusion: Our results indicate that class 1 and 2 integrons are common among Proteeae isolates. Meanwhile, qnrD are highly prevalent in Proteeae isolated from our hospital. [ABSTRACT FROM AUTHOR]

With recent improvements to living standards and renovations to many residential buildings, a large volume of new building materials have been utilized throughout China. Formaldehyde and other kinds of VOC pollutants, such as benzene, toluene and xylene found in new building materials, however, emit gases that may lead to some direct or potential health problems. Bake-out with dilution ventilation technology has the potential to shorten emission cycles of indoor air pollution, by which off-gassing from building materials can be reduced. In this paper, a test chamber was used to represent a newly renovated residential room in China. Experiments were conducted to study the applicability of the technology for removing of formaldehyde, benzene, toluene and xylene. A numerical method was used to simulate a 1 m3-chamber-TVOC removing amount under different operating conditions and the concentration change of TVOC during the bake-out exhaust dilution process. The effects of bake-out temperatures and times, ventilation times, and air change rates on removal are also discussed. Implications:VOCs are the main study objective in this paper. With higher baking temperature, longer baking time and longer ventilation time, the removal efficiency is higher in experiment. Removal content of TVOC increases with the increasing number of ACH. With the consideration of energy consumption, it is more reasonable to choose a ventilation time of 4 hours if ACH is 1.2 times/h. [ABSTRACT FROM AUTHOR]

The transport and storage of phosphorus in estuary is a complex biogeochemical process as the result of the convergence of fresh and saline water. The objective of the current study is to investigate the spatial-temporal variations of phosphorus fractions in surface water and suspended particles of Daliao River Estuary, China. Samples were collected in August (wet season) and November (dry season), 2013. The results showed that total particulate phosphorus (TPP) in water accounted for more than 50 % of the total phosphorus (TP). Meanwhile, in suspended particles, more than 62 % of particulate phosphorus was in the form of bioavailable phosphorus, including exchangeable phosphorus (Exc-P), extractable organic phosphorus (Exo-P), and iron-bound phosphorus (Fe-P), which meant that the potential impacts of bioavailable phosphorus in suspended particles on estuarine water environment cannot be ignored. There were significantly seasonal variations of phosphorus fractions in the Daliao River Estuary. The concentrations of phosphorus fractions in water in wet season were much lower than that in dry season because of the dilution effect of larger rainfall in wet season. In addition, spatial distribution characteristics of phosphorus fractions were also obvious. Due to terrigenous phosphorus input from the upstream of tidal reach and seawater dilution effect in coastal estuary, total dissolved phosphorus (TDP) concentrations in water gradually decreased from tidal reach to coastal estuary. However, the concentrations of TPP and TP in water and Exo-P in suspended particles presented spatial fluctuation, and these were greatly attributed to sediment re-suspension in coastal estuary. [ABSTRACT FROM AUTHOR]

The environmental constraint caused by intensification of rice production in China has raised the need to adjust crop nitrogen (N) fertilizer requirement. Leaf area index (LAI)-based assessment of crop N status can be an effective approach to optimizing N management in rice production. This study was designed to develop a new methodology for establishing the critical nitrogen (N c ) dilution curve based on LAI, to compare if a N c dilution curve based on LAI would allow a better diagnosis of N nutrition status than that on plant dry matter (PDM) basis and to assess its applicability for estimating plant N status in Japonica rice ( Oryza sativa L) in east China. Three field experiments with varied N rates (0–360 kg N ha −1 ) were conducted using three Japonica rice hybrids, Lingxiangyou-18 (LXY-18), Wuxiangjing-14 (WXJ-14) and Wuyunjing (WYJ) in lower Yangtze River reaches. LAI and plant N concentration (PNC) were determined from active tillering to heading for growth analysis in each experiment. The LAI and PNC ranged from 0.29 to 7.46 and 0.99 to 3.11%, respectively, under the varied experiment conditions. The relationship between N uptake and LAI expansion are strictly proportional and robust across the environments. The N c dilution curve (N c = 3.70LAI −0.35 ) was validated for N-limiting and non-N-limiting growth conditions. The N nutrition index (NNI) and accumulated N deficit (N and ) ranged from 0.69 to 1.06 and 88.8 to −7.54 kg ha −1 , respectively, over main growth stages. The values of Δ N derived from either NNI or N and could be used as references for in-season N dressing management in rice. Our results indicate that N c dilution curve as a function of LAI efficiently identified the conditions of limiting and non-limiting N nutrition and can be adopted as a novel tool for evaluating plant N status for precision N management in Japonica rice of east China. [ABSTRACT FROM AUTHOR]

Highlights: [•] A new critical nitrogen (N c) dilution curve based on leaf dry matter (L DM) was developed for Japonica rice in east China. [•] The N c was proposed for diagnosis of the in-season N status in rice plants. [•] The present results could be reliably used for assessing N status and guiding N management during growth of Japonica rice in east China. [ABSTRACT FROM AUTHOR]

ABSTRACT Due to the temporal decoupling of water and sediment sources in a large river basin, a flood from a sediment source area with high suspended sediment concentration (SSC) may be diluted by flow from a major runoff source area with low SSC. In this paper, this dilution effect is considered for 145 flood events from the Yellow River, China. Two indices ( β1 and β2) describing the dilution effect are proposed, based on water and sediment from the clear water source area and the coarse sediment producing area. Regression equations between channel sedimentation ( Sdep) and β1 and β2 are established based on flood events and annual data, respectively. The results show that dilution reduces channel sedimentation in the lower reaches by 34∙1% and that this is related to a reduced frequency of hyperconcentrated flows in the lower reaches. The Longyangxia Reservoir for hydro-electric generation has stored huge quantities of clear runoff from the upper Yellow River during high-flow season since 1985, greatly reducing the dilution of the hyperconcentrated floods and therefore enhancing sedimentation in the lower reaches. For the purpose of reducing sedimentation, changing the operational mode of the Longyangxia Reservoir to restore the dilution effect is suggested. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] The leaf Nc curve developed in this paper has not been reported in previous research. [•] The present leaf Nc curve was lower than the reference plant Nc curve. [•] There was a significant positive relationship between NNI and N applications. [•] The leaf Nc curve can be used to diagnose the N status of winter wheat in eastern China. [ABSTRACT FROM AUTHOR]

High sediment flux in large rivers provide sufficient dilution to the heavy metals' concentration. However, sediment starvation caused by hydrological engineering in recent decades has been reported worldwide. Thus, a study is necessary on the influences of recent declining sediment flux on heavy metal pollution change in the suspended sediments. In this study, heavy metal concentrations and speciation (Cd, Pb, Zn, Cu, Co, Ni, and Cr) in suspended sediments were investigated downstream the Three Gorges Dam (TGD) during dry and flood seasons. Substantial changes of Pb, Zn, Cd, and Cu along the river channel were found which were constrained by the dilution efficiency of suspended sediment during the dry season. High proportion of labile fraction revealed anthropogenic sources of heavy metal. Moreover, the historical trend of metal content illustrated TGD construction together with anthropogenic influx both contribute to the increasing environmental risk in the Yangtze River basin., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

In the present study, δ15N and δ18O-NO3- values, as well as concentrations of some major ion tracers were determined in seasonal water samples from Taihu Lake and major watersheds to investigate the temporal and spatial variations of nitrate sources and assess the underlying nitrogen (N) biogeochemistry process. The results lead to the conclusion that the nitrate concentrations in Taihu Lake are lower in summer than that in winter due to the dilution effect of wet deposition. In winter, sewage and manure were the primary nitrate sources in major inflow rivers and North Taihu Lake (NTL), while nitrate sources in East Taihu Lake (ETL) probably derived from soil organic N. In summer, atmospheric deposition and sewage/manure inputs appear to play an important role in controlling the distribution of nitrates in the whole lake. The δ18O-NO3- values suggest that the nitrate produced from microbial nitrification is another major nitrate source during both winter and summer months. The variations in isotopic values in nitrate suggest denitrification enriched the heavier isotopes of nitrate in NTL in winter and in ETL in summer. [ABSTRACT FROM AUTHOR]

Abstract: By means of computational fluid dynamic (CFD) simulations, this paper investigated how rural winds transport relatively clean air into high-rise urban areas to dilute airborne pollutants. Two ventilation concepts for indoor environments were applied: the age of air to quantify the time taken by rural young air to reach a given place after it enters an urban area and the air exchange efficiency to evaluate the efficiency of rural winds flushing the entire urban canopy layer. Several square building arrays with street aspect ratios (building height/street width, H/W) ranging from 1.5 to 5.3 and building area densities of 0.25 (medium) or 0.4 (compact) were considered as the approaching wind is parallel to the main street whose length varies from street scales to neighborhood scales (330–510 m to 1.03–1.65 km in full-scale). Results show that considerable young rural air enters windward entries but a major fraction of air is vertically driven out as flowing deeper into such high-rise building arrays. So air exchange efficiencies are less than 50% in street-scale arrays, and smaller in longer (neighborhood-scale) or narrower arrays. For the neighborhood-scale medium arrays, considering the power-law velocity profile in the upstream free flow, a taller array gains a larger inflow rate across its windward entry and experiences younger air and greater air exchange efficiency than a lower one. If all buildings are theoretically open-based in a neighborhood-scale compact array, air becomes much younger everywhere and the air exchange efficiency doubles. In arrays of buildings with different heights, the secondary streets in front of taller buildings get younger air due to the downward flows within them. Although further investigations are still required before providing a practical framework, this paper is one of the first attempts to find ways in improving the ventilation performance in high-rise cities like Hong Kong. [Copyright &y& Elsevier]

A new type of REE tetrad effect, a composite M- and W-type, was recognized in the K-feldsparthized and silicificated Shuiquangou alkaline syenites, Dongping, Hebei Province. Different analytical methods such as ICP-MS and isotopic dilution thermal ion mass spectrometer were exploited to verify the REE concentrations of the samples in three laboratories in China, France and Korea. The results are reliable and consistent within errors. In situ quantitative analysis of REE concentrations of individual zircons and apatites extracted from the very same sample has shown that fractional crystallization of magma and the superimposed hydrothermal alteration might have taken place in at least two-stage hydrothermal activities to generate the composite M- and W-type REE tetrad effect. The coexisting melt and aqueous phases, the superimposed alteration by volatile (Cl, CO2)- and Si, K, Al-enriched high temperature hydrothermal fluids might be the important facts for this new MW-type of REE tetrad effect. In addition, the peculiar MW-type tetrad effect might be an indicator for Au mineralization of reworked plutons. [ABSTRACT FROM AUTHOR]

Abstract: Compositing of borehole assay intervals based on economic aspects is a primary step when the cross-sectional method is applied in orebody modelling and mineral resources estimation. The compositing is important because the resulting ore composites eventually determine the outlines of orebody models. However, numerous boreholes and borehole intervals make ore compositing tedious and time-consuming for manual work. A computer program for compositing is desirable to facilitate the task and to obtain accurate results. In the design of computer algorithms for such a computer program, dilution is the most difficult part because dilution means adding waste intervals into an ore composite in order to transfer it from unminable to minable and this causes some special situations in a compositing procedure. In order to obtain economically optimized compositing results, we paid special attention to dilution in the designed algorithms. A demo program has been developed to test and implement these algorithms using borehole assay datasets from a mine site in China. Results show the accuracy of designed computer algorithms and the feasibility of applying a computer program in compositing of borehole assay intervals. [Copyright &y& Elsevier]

Neo-liberalism is an important means of strategy for the Western to do evolution to the Socialist countries. On the economic level, it impacts the building of the Socialism with Chinese Characteristics and the direction of reform; at the political level, it pushes forward the change of the basic political system of the Socialism with Chinese Characteristics; on the cultural level, it promotes the so-called "Universal Value" to dilute the Core Values of the Socialism with Chinese Characteristics. In this regard, it is necessary to understand the essential of the characteristics of neo--liberalism correctly, to realize the achievements and problems of China's reform and opening up comprehensively and to recognize the importance of the construction of Core Values of the Socialism with Chinese Characteristics in guiding China's cultural construction scientifically. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the effects of enhanced nutrient loading in estuarine waters on the growth of phytoplankton, and grazing of microzooplankton through monthly dilution experiments conducted at two contrasting sites in the coastal waters of Hong Kong, China. It discusses the contrasting trophic conditions of the two sites which include the western estuarine station (WE) near the Pearl River estuary, and the eastern oceanic station (EO). The study reveals that nutrient limitation of phytoplankton growth occurred more often at EO than WE, while the latter demonstrated higher phytoplankton growth and microzooplankton grazing rates. The study confirms the role of microzooplankton grazing as a dominant loss pathway for phytoplankton in eutrophic coastal environments.

Lacustrine rift basins in Eastern China possess large amounts of petroleum, especially the shale gas and tight sand gas in deep formations, where "sweet spots" are closely related to organic-rich shale intervals. However, the OM enrichment of deep formation shale in lacustrine rift basins and the main controlling factors have not been well-researched in previous studies. The organic matter (OM) enrichment is mainly controlled by the OM input, preservation, and/or dilution. The shales deposited in deep formations of Songliao Basin, including the Jurassic Huoshiling (J 3 h), Cretaceous Shahezi (K 1 sh), and Yingcheng (K 1 yc) formations, are evaluated as fair to excellent source rocks. Taking the shales as an example, the characters and impact of input, preservation, and dilution on OM enrichment in shales are discussed by utilizing the parameters of element concentrations and biomarkers. Results show that the OM sources are mixed sources of aquatic microorganisms and higher plant materials, and the higher plant materials are dominant. The bio-productivity were moderate to high. The paleoclimate was mainly the cold and semi-humid to semi-arid. The lake salinity was fresh-to brackish-water. The redox conditions were sub-reducing to sub-oxidizing. The dilution degree in Yingcheng was the strongest, followed by the Shahezi and Huoshiling. Consequently, the OM enrichment in the J 3 h shale was called moderate bio-productivity and preservation model; the OM enrichment in the K 1 sh shale was called high bio-productivity and preservation model; the OM enrichment in the K 1 yc shale was named high dilution model. This study not only improves the model of OM enrichment but also provide some information for the research of "Deep time" in the Cretaceous of Songliao Basin, guiding the prediction of organic-rich shale distribution in lacustrine rift basin. • Fair to excellent hydrocarbon generation potential. • Organic matter origins are mainly a mixture of aquatic microorganisms and terrestrial higher plants. • Arid and cold paleoclimate and fresh- and brackish-water. • Reducing to sub-reducing, sub-reducing to oxidizing, and sub-reducing to sub-oxidizing conditions. • Moderate bio-productivity and preservation model, high bio-productivity and preservation model, high dilution model. [ABSTRACT FROM AUTHOR]

The article reports on a study which examines Chinese Acidithiobacillus and reference strains by randomly amplified polymorphic DNA and sequencing of the 16s rDNA and the 16S-23S rDNA internally transcribed spacer (ITS). According to the authors of the study, samples of water and sediment were collected from different mining sites in China. The samples were serially diluted and spread onto a variety of solid media specifically designed for isolating acidophilic sulfur-oxidizing and iron-oxidizing bacteria. The study showed that ITS may be a potential target for the development of fluorescent in situ hybridization probes for more accurately detecting distinct ecotypes of Acidithiobacillus strains and other closely related sulfur-oxidizing bacteria.

A continuous high-resolution (monthly) record of stable isotopes (δ13C and δ18O) in a well-laminated freshwater travertine deposited at Baishuitai, SW China from May 1998 to November 2001 was presented. The travertine exhibits clear annual bands with coupled brown/white color laminations. Throughout field investigation, it was found that the thin (1.5–2.2 mm), brown porous lamina was formed in the monsoonal rainy season from April to September, whereas the thick (5–8 mm), dense white lamina was formed in the dry season from October to March. The comparisons of lamina thickness and stable isotope signals in the travertine with the meteorological records allow us to constrain the relevant geochemical processes in the travertine formation under different climate conditions and to relate climate variables to their physicochemical proxies in the travertine record. Sympathetic variations in lamina thickness, δ13C and δ18O along the sampled profile reflect changes in hydrogeochemistry, showing that thin lamina and low δ13C and δ18O values occur in warm and rainy seasons. The decreased amount of calcite precipitation and low δ13C values during the warm and rainy seasons is caused by dilution of overland flow after rainfall. The low δ18O values are believed to be related to the rainfall amount effect in subtropical monsoonal regions. This process is thought to be markedly subdued whenever the amount of rainfall is lower than a given threshold. Accordingly, distinct minima in lamina thickness, δ13C and δ18O are interpreted to reflect events with above-average rainfall, possibly heavy floods, and vice versa. This study demonstrates the potential of freshwater travertine to provide valuable information on seasonal or even monthly rainfall variations. [ABSTRACT FROM AUTHOR]

No abstract available. [ABSTRACT FROM AUTHOR]

Abstract: The water column distributions of dissolved cadmium and supporting parameters were determined during a cruise in the South China Sea in October, 2002. The investigation was focused on waters of the shelf and the central basin which have depths of <200m and >2000m, respectively. In the surface waters, concentrations of Cd were 0.07–0.95 and 0.05–0.15nM for the shelf and central basin, respectively. The spatial distributions in the surface waters show that concentrations of Cd were relatively high in the Pearl River Estuary. In contrast, Cd was totally depleted in surface waters of the deep water basin. This is attributed to the riverine inputs from the East Asian continent in the shelf regions. The influence of riverine input is reduced by dilution process with waters containing low concentrations of Cd waters. In the central basin, vertical profiles of Cd show a nutrient-like distribution which is depleted in the surface, increases with depth to about 1000m, and that is finally maintained within a narrow concentration range of 0.94–0.99nM in the deep water. Here, the Cd/PO4 ratio was 0.369±0.011nM Cd/μM PO4, indicating that the biogeochemical processes of Cd and PO4 are similar to that in marginal seas of the western Pacific Ocean. However, the concentration gradients in surface waters show a southward increase. The results indicate that the relative enrichment of nutrients and the nutricline uplifted sharply in surface waters of the southern SCS. [Copyright &y& Elsevier]

In China particulate matter (PM) is the leading environmental risk factor to morbidity and mortality, with transport being the main source of PM pollution in cities. China VI emission limit standards, which are one of the most stringent worldwide, have only recently been introduced and there is lack of studies assessing the PM emissions of new engines. In Europe, there are discussions ongoing to permit sampling directly from the tailpipe with fixed dilution for determining the solid particle number (SPN) emissions during type approval of heavy duty engines; something that is practically allowed for on-road testing. In this study the particulate emissions of seven engines were measured. Three of them were fulfilling the China VI limits, two China V, while two of them were China III engines retrofitted with diesel particulate filters (DPFs). One system with evaporation tube was installed at the full dilution tunnel, as prescribed in the regulation, and another one with catalytic stripper was sampling from the tailpipe, both measuring >23 nm and >10 nm particles. The results showed a wide range of particulate emission levels depending on the engine, the existence of a DPF, the connection point of the crankcase ventilation, and the occurrence of active or passive regeneration. The system at the tailpipe measured on average 20% lower than the system at the dilution tunnel. The system at the dilution tunnel measured much higher during one regeneration due to re-nucleation of volatiles downstream of the evaporation tube. For one engine, the emissions of the evaporation tube system were more than double when the crankcase ventilation was connected downstream of the aftertreatment devices. The main message from this study is that a catalytic stripper is necessary for sub-23 nm measurements and tailpipe sampling with fixed dilution is a plausible option. • China III to VI engine particulate matter (PM) mass and particle number (PN) emissions. • Filtration efficiency of retrofitted diesel particulate filters. • Comparison of PN systems measuring from the tailpipe and the full dilution tunnel. • Contribution of crankcase ventilation to engine emissions. • Passive and active regeneration emissions. [ABSTRACT FROM AUTHOR]

Critical nitrogen (N c) dilution curves have been widely used for the plant N status diagnosis, N management, crop modeling, and remote sensing. Wheat is a major crop worldwide whose N c dilution curves developed under different conditions (genotype × environment × management) show large parameter variations. Herein, a dataset of 19 nitrogen fertilizer experiments (n = 656) from five wheat planting sites in China was used to evaluate the uncertainty in these curves and explain the sources of differences using the Bayesian theory method. The uncertainty of the fitted curve decreased with the increase in plant biomass. The parameter A 2 of fitted curves of genotype × environment × management combinations showed a greater variation than A 1 , with slight parameter differences among different genotypes and planting sites. The variables related to genotype and growth environment, i.e., maximum N concentration, maximum biomass, and accumulated growing degree days during the vegetative growth period, were the sources of differences in curve parameters. Though the N c curve differences between genotype × environment × management were statistically significant, the nitrogen nutrition index (NNI) differences remained relatively small. This study provides insights for developing a more diverse N c dilution curve to aid in optimal nitrogen fertilization management in wheat. [ABSTRACT FROM AUTHOR]

• Using different optical sensors indexes for developing nitrogen dilution curves. • Proving plant nitrogen accumulation is more reliable nitrogen status diagnosis indicator. • Comparing the performance of Greenseeker and SPAD meter in nitrogen nutrition diagnosis. Nitrogen (N) plays an essential role in the crop growing cycle. Canopy vegetation indexes and chlorophyll concentration were important tools in-crop N status diagnosis and provided a crucial guide for agricultural managers. This work focused on evaluating the performance of different chlorophyll-related indexes (canopy chlorophyll index, CCI) and Greenseeker RT 200 values (GS values, normalized difference vegetation index, NDVI & Ratio vegetation index, RVI) in crop N nutrient diagnosis. Four experiments were conducted with multiple N fertilizer rates (0 ∼ 390 kg N ha−1) and seven Japonica rice (Oryza sativa L.). Results suggested that the relationship between CCI value and tissue nitrogen accumulation [including leaf nitrogen accumulation (LNA) and plant N accumulation (PNA)] was more reliable than that of GS values. Compered GS values with CCI values-based N concentration dilution curves, CCI-based Nc curve showed better accuracy and lower bias than GS values-based curves. And this curve lower than the reference LAI basis Nc curve and higher than the dry matter-based curve. The N nutrition index (NNI), calculated by the CCI-based curve, ranged from 0.31 to 1.33 during the vegetative stage. A significant positive relationship between CCI values and accumulated N deficit (AND) applications over the rice developmental stages. This present study also proved that CCI could be used to predict grain yield in total growth periods. These developed canopy level vegetation indexes-based Nc curve as a novel tool to offer more choices for evaluating crop N nutrition status and precision N topdressing management in Japonica rice of China. [ABSTRACT FROM AUTHOR]

• There was an rapidly increase in plant critical dilution curve (PCDC) study in recent years. • PCDC has been applied to more than 30 species by the scientists from 40 countries. • INRA developed PCDC theory, institutions from China and Canada are emerging groups. • Crop modeling and remote sensing in PCDC studies significantly increased recently. The concept of plant critical dilution curve (PCDC) has been studied on several crop species for about four decades, which has been widely applied in studies of crop nutrition evaluation, growth predictions, and fertilization management. This bibliometric analysis comprehensively explores the evolution trends in PCDC research based on literature data retrieved from the Web of Science from 1985 to 2019. The dynamics of the basic characteristics such as outputs, citations, institutions, authors, keywords and research topics of the published papers were studied. The results showed that the outputs and citations remained very low in the early years, then increased gradually, and increased quickly in recent years. INRA from France developed the theory, while research institutions from China and Canada as emerging groups applied the theory in different crops for crop N, growth, and quality indices as well as integrated it with non-destructive tools such as chlorophyll meter and remote sensing technologies in recent years. The frequency of the keywords "nitrogen nutrition index", "use efficiency", "management", "leaf area index" and "vegetation index" in the PCDC study increased over years. The PCDCs along with a number of crops, such as wheat, maize, rice, forage grasses, potato, canola, and tomato, have been widely studied in different countries. Research on PCDC has mainly focused on the theory and development of PCDC, including P, K, S, and their interaction, crop modeling, remote sensing and non-destructive techniques, nutrition diagnosis and fertilization management. Analysis of the published papers revealed that crop modeling and remote sensing are emerging fields. The research trends proposed were: generic PCDCs for crop species, the interaction of N-P-K-S for balanced fertilization, and application of PCDC in crop modeling and remote sensing. [ABSTRACT FROM AUTHOR]

• We present a Bayesian method for estimating parameters of critical nitrogen dilution curve. • It does not require the classification of nitrogen-limited against non-nitrogen-limited data. • It can be easily implemented using freely-available software. • This method is useful for analyzing uncertainty in the fitted critical nitrogen curves. • It can take prior knowledge about parameter values into account. Nitrogen critical curves are frequently used to diagnose the N status of crops and grasslands. They play an important role in plant modelling and are frequently used in fertilizer management tools. During the last 20 years, a number of studies have been conducted for comparing critical curves obtained in various conditions (e.g., different cultivars) and understanding the origin of their differences. However, uncertainty in the determination of these curves is generally poorly analyzed in these studies, which increase the risk of false conclusions, in particular on the existence of differences between species, cultivars and cropping systems. Here, we present a Bayesian statistical model for estimating parameters of critical nitrogen dilution curve from experimental data. Contrary to standard methods commonly used for fitting critical nitrogen dilution curves, the proposed approach allows one to fit these curves in only one step, i.e., directly from the original biomass and nitrogen content measurements. Specifically, this method does not require the classification of nitrogen-limited data against non-nitrogen-limited data and does not necessitate the preliminary identification of critical nitrogen concentrations. Another advantage of the proposed method is that it can be easily implemented using freely-available software. We illustrate its practical interest using experimental data collected for winter wheat in France, and for maize and rice in China. We show that this method is useful for analyzing uncertainty in the fitted critical nitrogen curves and for comparing several curves obtained for different crop species and cultivars. The proposed method is based on the specification of prior probability distributions defining plausible ranges of values for the critical curve parameters, and we show here that it is preferable to use prior distributions that are not very informative if we want to limit their influence on the final result. [ABSTRACT FROM AUTHOR]

• Tuff zircon TIMS U-Pb age of 720.16 ± 1.40 Ma was reported from the upper Gongdong Formation; • Monte Carlo simulation suggests a 717.61 ± 1.65 Ma onset age for the Sturtian glaciation in South China; • New age is consistent with the geochronological records in Laurentia and the Arabian-Nubian Shield; • New age represents an important step forward for testing rapid and synchronous global Sturtian glaciation. Neoproterozoic glaciations have drawn worldwide attention in recent years because of their influence on atmosphere, hydrosphere, biosphere, lithosphere, and potential causal relationship to the subsequent Cambrian evolutionary explosion which represents the most important event in the history of life on Earth. The Snowball Earth hypothesis predicts a rapid and synchronous initiation of the Neoproterozoic glaciations, but convincing radiometric dates to constrain this hypothesis are yet to be established. Dating this event is often compromised by indistinct stratigraphic relationships and the presence of detrital zircon grains. In this study, we present a chemical abrasion–isotope dilution–isotope ratio mass spectrometry (CA-ID-IRMS) U-Pb zircon age from the upper Gongdong Formation of South China, ca. 25 m below the base of the Chang'an diamictite. This new data combined with Monte Carlo modelling suggests the onset of the Sturtian glaciation, in South China, occurred after <718.8 Ma, possibly 717.61 ± 1.65 Ma. This new age is consistent with the geochronological records in Laurentia and the Arabian-Nubian Shield, an important step forward for testing rapid and synchronous global Sturtian glaciation. [ABSTRACT FROM AUTHOR]

Hydrochemical behaviour and dissolved carbon dynamics have high sensitivity to hydrologicvariations during high-flow periods in monsoonal-influenced regions, especially inthe critical zone of agricultural karstic catchment where existing anthropogenicinterference and carbonate weathering with rapid kinetics. Here we selected Chenqicatchment, a 1.5 km2 sub-catchment of Houzhai basin in Puding, SW China, as studyarea to analyze the response of hydrochemistry and dissolved carbon dynamicsto discharge changes, through hourly sampling campaigns in the outlet of springwater during the high-flow period. Most dissolved ions exhibit distinct responsesto discharge variations, their concentrations are negatively correlated with springwater discharge, which can be well fitted using power-law function, indicating theirchemostatic behaviours as discharge increases, but biogeochemical processes influencingdifferent ions are miscellaneous. Ca2+, Mg2+ and HCO3− are mainly controlled bydissolved soil CO2 and carbonate weathering, while NO3− and Cl− both haveanthropogenic inputs and may exist some link about their source areas or transport processesactivated during high-flow periods. Other ions are generally affected by the dilution ofrainwater. Hydrological conditions and biogeochemical processes regulate dissolvedcarbon dynamics, resulting in the variation of δ13CDIC. There are two sources forDIC in spring water of Chenqi catchment, namely biological source (DICbio) andgeological source (DICcarb). The contribution ratio of DICbio is around thrice that ofDICcarb, and they both show chemostatic response to varying discharge althoughthe degrees for DICbio is stronger. The response of dissolved carbon dynamics todischarge variations display different degrees at different stages of the wet season. Itwas find that most dissolved solutes (except DOC) normally present clockwisehysteresis loops plotting from the top-left to bottom-right due to the dilution onthe rising limb of the storm, but the loop area and hysteresis index are differentwithin or between diverse storms. The pattern is related to rain intensity/amount andantecedent conditions, which can affect flow pathways and likely source areas, leadingto different transport time and loads. These hysteresis behaviours are generallycontrolled by antecedent conditions of storms, range/peak of discharge and soluteconcentrations, and storm duration. Overall, this study highlighted the sensitivecharacteristics of hydrochemistry and dissolved carbon dynamics to hydrologicalvariations in small agricultural karstic catchment based on high resolution information. [ABSTRACT FROM AUTHOR]