The amount and intensity of precipitation may have important effects on plant growth and ecosystem carbon exchange in semiarid desert steppes; further understanding of how the dryland carbon cycle ...responds to changes in precipitation and its underlying mechanisms is necessary for an accurate understanding of the global carbon cycle. A field experiment was conducted in a semiarid desert steppe in Ningxia, China, to clarify the response patterns of ecosystem carbon fluxes along five levels of precipitation gradients (Simulating the natural precipitation percentages of 33 % (−33 %, 84 mm), 66 % (−66 %, 167 mm), 100 % (CK, 253 mm), 133 % (+33 %, 336 mm) and 166 % (+66 %, 420 mm) by rain shelters and sprinklers; CK is natural precipitation). The result showed that the trends of net ecosystem CO2 exchange (NEE) and gross ecosystem photosynthesis (GEP) were consistent and those of ecosystem respiration (ER) and Soil respiration (SR) and autotrophic (Ra) and heterotrophic (Rh) components of SR were also consistent. NEE, ER, GEP and SR all reached their highest values in August. Changes in precipitation significantly affected ecosystem carbon fluxes, with NEE, ER and SR decreasing with decreasing precipitation and NEE, ER and GEP increasing with increasing precipitation. Soil respiration was more sensitive to the decreased precipitation treatment. During the growing season, NEE, ER, GEP, and SR were significantly positively correlated with precipitation, soil moisture (SM) and aboveground biomass (AGB). With the increase of precipitation variability, the promotion effect of increasing precipitation on GEP will exceed the promotion effect on ER, causing changes in carbon exchange and carbon sinks. Photosynthesis and respiration appeared tightly coupled, indicating that photosynthetic products regulate above- and belowground carbon cycling in semiarid steppe. Our study highlights the importance of water availability in carbon exchange processes in semiarid desert steppe of northern China. Decreased precipitation can lead to significant changes in SM and AGB, with negative impacts on GEP and SR, resulting in uncertainty in regional carbon sequestration. These findings will help us understand the vulnerability of semiarid steppe ecosystems under the influence of future precipitation changes and aim to provide a scientific reference for ecological management and restoration of semiarid desert steppes.
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•Effect of precipitation changes on above- and below-ground carbon fluxes was studied.•Increased precipitation promotes GEP more than ER, leading to carbon sinks.•Soil respiration was more sensitive to the decreased precipitation treatment.•There is a strong coupling between photosynthesis and soil respiration.
The origins and logging responses of flushed zones in some blocks of Orinoco heavy oil belt, Venezuela are still unclear. To solve this issue, we examined the conventional logging, nuclear magnetic ...resonance logging, fluid viscosity, core analysis and oil field production data comprehensively to find out the logging responses and origins of the flushed zones. The results show that the main reason for the formation of flushed zone is surface water invasion, which leads to crude oil densification. The crude oil densification produces asphalt membrane (asphalt crust) which wraps up free water, causing special logging responses of the flushed zones. According to the different logging responses, we classified the flushed zones into two types and analyzed the formation processes of the two types of flushed zones. According to the characteristics of logging curves after water flush, we confirmed that the water flush began earlier than the reservoir accumulation.
We aimed to investigate the prevalence of hyperhomocysteinaemia (total plasma homocysteine (tHcy) ≥ 10 μmol/l) and its major determinants in rural Chinese hypertensive patients. A cross-sectional ...investigation was carried out in Lianyungang of Jiangsu province, China. This analysis included 13 946 hypertensive adults. The prevalence of hyperhomocysteinaemia was 51.6 % (42.7 % in women and 65.6 % in men). The OR of hyperhomocysteinaemia were 1.52 (95 % CI 1.39, 1.67) and 2.32 (95 % CI 2.07, 2.61) for participants aged 55-65 and 65-75 v. 45-55 years; 1.27 (95 % CI 1.18, 1.37) for participants with a BMI ≥ 25 v. < 25 kg/m²; 1.14 (95 % CI 1.06, 1.23) for participants with v. without antihypertensive treatment; 1.09 (95 % CI 1.00, 1.18) for residents inland v. coastal; 0.89 (95 % CI 0.82, 0.97) and 0.83 (95 % CI 0.74, 0.92) for participants with moderate and high v. low physical activity levels; 1.54 (95 % CI 1.41, 1.68) and 2.47 (95 % CI 2.17, 2.81) for participants with a glomerular filtration rate 60-90 and < 60 v. ≥ 90 ml/min per 1.73 m²; and 1.20 (95 % CI 1.07, 1.35) and 3.81 (95 % CI 3.33, 4.36) for participants with CT and TT v. CC genotype at methylenetetrahydrofolate reductase 677C>T polymorphism, respectively. Furthermore, higher tHcy concentrations were observed in smokers of both sexes (men: geometric mean 12.1 (interquartile range (IQR) 9.2-14.5) v. 11.9 (IQR 9.-14.) μmol/l, P= 0.005; women: geometric mean 10·3 (IQR 8.3-13.0) v. 9.6 (IQR 7.8-11.6) μmol/l, P= 0.010), and only in males with hypertension grade 3 (v. grade 1 or controlled blood pressure) (geometric mean 12.1 (IQR 9.2-14.4) v. 11.7 (IQR 9.2-14.0), P= 0.016) and in male non-drinkers (yes v. no) (geometric mean 12.3 (IQR 9.4-14.8) v. 11.7 (IQR 9.1-13.9), P= 0.014). In conclusion, there was a high prevalence of hyperhomocysteinaemia in Chinese hypertensive adults, particularly in the inlanders, who may benefit greatly from tHcy-lowering strategies, such as folic acid supplementation and lifestyle change.
Based on the spatially resolvable data of the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Nobeyama Radio Heliograph (NoRH), co-analysis of solar hard X-ray and microwave ...spectral evolution is performed in three separate sources located in one looptop (LT) and two footpoints (FPs) of a huge flaring loop in the 2003 October 24 flare. The RHESSI image spectral evolution in 10-100 keV is always fitted by the well-known soft-hard-soft (SHS) pattern in the three sources. When the total energy is divided into four intervals similar to the Yohkoh/Hard X-ray Telescope, i.e., 12.5-32.5 keV, 32.5-52.5 keV, 52.5-72.5 keV, and 72.5-97.5 keV, the SHS pattern in lower energies is converted gradually to the hard-soft-hard (HSH) pattern in higher energies in all three sources. However, the break energy in the LT and the northeast FP (~32.5 keV) is evidently smaller than that in the southwest FP (~72.5 keV). Regarding microwave spectral evolution of the NoRH data, the well-known soft-hard-harder pattern appeared in the southwest FP, while the HSH pattern coexisted in the LT and the northeast FP. The different features of the hard X-ray and microwave spectral evolutions in the three sources may be explained by the loop-loop interaction with another huge loop in the LT and with a compact loop in the northeast FP, where the trapping effect is much stronger than that in the southwest FP. The comparison between the LT and FP spectral indices suggests that the radiation mechanism of X-rays may be quite different in different energy intervals and sources. The calculated electron spectral indices from the predicted mechanisms of X-rays gradually become closer to those from the microwave data with increasing X-ray energies.
Cell-based assays (CBAs) and radioimmunoprecipitation assay (RIPA) are the most sensitive methods for identifying anti-acetylcholine receptor (AChR) antibody in myasthenia gravis (MG). But CBAs are ...limited in clinical practice by transient transfection. We established a stable cell line (KL525) expressing clustered AChR by infecting HEK 293T cells with dual lentiviral vectors expressing the genes encoding the human AChR α1, β1, δ, ϵ and the clustering protein rapsyn. We verified the stable expression of human clustered AChR by immunofluorescence, immunoblotting, and real-time PCR. Fluorescence-activated cell sorting (FACS) was used to detect anti-AChR antibodies in 103 MG patients and 58 healthy individuals. The positive results of MG patients reported by the KL525 was 80.6% (83/103), 29.1% higher than the 51.4% (53/103) of RIPA. 58 healthy individuals tested by both the KL525 CBA and RIPA were all negative. In summary, the stable expression of clustered AChR in our cell line makes it highly sensitive and advantageous for broad clinical application in CBAs.
Rotational grazing is an effective way to improve grassland resources utilization and develop animal husbandry. Rational grazing scheme can avoid eco-environment damage caused by overgrazing, and it ...can ensure the livestock normal feeding. The rationality of rotational grazing management is affected by many complex and dynamic factors. This paper establishes a model of rotational grazing assignment based on grass resource leveling. Firstly, each rotational grazing plot’s forage yield in each rotational grazing assignment stage is predicted by seasonal prediction method. Then, constrained by the rotational grazing plots’ forage yield and livestock’s forage demand, a dynamic rotational grazing assignment model is established, which combines the assignment model and carrying capacity constraint. Thus, the maximum edible forage in a rotational grazing cycle is contained and the distribution of the corresponding rotational grazing plots is determined. In each rotational grazing cycle, each rotational grazing plot can only be assigned once, which embodies the principle of ecological protection. And livestock have as much forage as possible in a rotational grazing cycle. Finally, through a case analysis, a feasible solution in a rotational grazing cycle is obtained. Through taking carrying capacity in each rotational grazing assignment stage as a standard to scheme the grazing order in each plot, the uncertainty of eco-environment is better reflected. A reasonable decision scheme of dynamic rotational grazing can make resources used efficiently in time and space.
Through introducing the generalized Vandermonde determinant, the linear algebraic system of a kind of Vandermonde equations is solved analytically by use of the basic properties of this determinant, ...and then we present general explicit finite difference formulas with arbitrary order accuracy for approximating first and higher derivatives, which are applicable to unequally or equally spaced data. Comparing with other finite difference formulas, the new explicit difference formulas have some important advantages. Basic computer algorithms for the new formulas are given, and numerical results show that the new explicit difference formulas are quite effective for estimating first and higher derivatives of equally and unequally spaced data.
There is an increasing drug resistance of animal-derived pathogens, seriously posing a huge threat to the health of animals and humans. Traditional drug resistance testing methods are expensive, have ...low efficiency, and are time-consuming, making it difficult to evaluate overall drug resistance. To develop a better approach to detect drug resistance, a small sample of Escherichia coli resistance data from 2003 to 2014 in Chengdu, Sichuan Province was used, and multiple regression interpolation was applied to impute missing data based on the time series. Next, cluster analysis was used to classify anti-E. coli drugs. According to the classification results, a GM(1,1)-BP model was selected to analyze the changes in the drug resistance of E. coli, and a drug resistance prediction system was constructed based on the GM(1,1)-BP Neural Network model. The GM(1,1)-BP Neural Network model showed a good prediction effect using a small sample of drug resistance data, with a determination coefficient R2 of 0.7830 and an RMSE of only 0.0527. This model can be applied for the prediction of drug resistance trends of other animal-derived pathogenic bacteria, and provides the scientific and technical means for the effective assessment of bacterial resistance.
Feeding pelleted total mixed rations (TMR) instead of traditional loose concentrate plus forage to fattening lambs is an emerging practice. This study aimed to determine the effects of feeding ...pelleted TMR to fattening lambs on feed intake behaviour, growth performance, feed digestion, rumen fermentation characteristics, rumen microbial community, serum parameters, slaughter performance, meat quality, and the economic outcome. Two physical forms (pelleted vs. un-pelleted) of TMR composed of the same ingredients with the same particle sizes were compared in three animal experiments. Feed intake and average daily gain were higher when the TMR was pelleted, but apparent total tract digestibility of nutrients (organic matter, crude protein, neutral detergent fibre, acid detergent fibre, and ether extract) and serum parameters were not affected and apparent total tract dry matter digestibility was slightly lower. Feeding pelleted TMR increased total short-chain fatty acid concentration and decreased rumen pH. Rumen microbial community was not affected by the physical form of the TMR at phylum level but changed slightly at genus level. Liveweight at slaughter and hot carcass weight were higher for lambs fed the pelleted compared to the un-pelleted TMR, while dressing percentage and meat quality were not affected. In conclusion, feeding pelleted TMR improves growth performance of fattening lambs mainly due to an increase in feed intake. Feeding pelleted TMR is a feasible strategy for intensive lamb fattening operations.
In this study, Fe-25Mn-xAl-8Ni-C alloys (x = 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%) were prepared by a vacuum arc melting method, and the microstructure of this series of alloys and the in situ tensile ...deformation behavior were studied. The results showed that Fe-25Mn-xAl-8Ni-C alloys mainly contained austenite phase with a small amount of NiAl compound. With the content of Al increasing, the amount of austenite decreased while the amount of NiAl compound increased. When the Al content increased to 12 wt.%, the interface between austenite and NiAl compound and austenitic internal started to precipitate k-carbide phase. In situ tensile results also showed that as the content of Al increased, the alloy elongation decreased gradually, and the tensile strength first increased and then decreased. When the Al content was up to 11 wt.%, the elongation and tensile strength were 2.6% and 702.5 MPa, respectively; the results of in situ tensile dynamic observations show that during the process of stretching, austenite deformed first, and crack initiation mainly occurred at the interface between austenite and NiAl compound, and propagated along the interface, resulting in fracture of the alloy.
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