• Background and Aims Elucidating the stoichiometry and resorption patterns of multiple nutrients is an essential requirement for a holistic understanding of plant nutrition and biogeochemical ...cycling. However, most studies have focused on nitrogen (N) and phosphorus (P), and largely ignored other nutrients. The current study aimed to determine relationships between résorption patterns and leaf nutrient status for 13 nutrient elements in a karst vegetation region. • Methods Plant and soil samples were collected from four vegetation types in the karst region of south-western China and divided into eight plant functional types. Samples of newly expanded and recently senesced leaves were analysed to determine concentrations of boron (B), calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), molybdenum (Mo), N, sodium (Na), P, sulphur (S) and zinc (Zn). • Key Results Nutrient concentrations of the karst plants were lower than those normally found in other regions of China and the rest of the world, and plant growth was mainly limited by P. Overall, four nutrients revealed resorption N (resorption efficiency 34·6 %), P (48·4 %), K (63·2 %) and Mg (13·2 %), seven nutrients B (–16·1 %), Ca (–44·0 %), Cu (–14·5 %), Fe (–205·5 %), Mn (–72·5 %), Mo(–35·6 %) and Zn (–184·3 %) showed accumulation in senesced leaves and two nutrients (Na and S) showed no resorption or accumulation. Resorption efficiencies of K and Mg and accumulation of B, Ca, Fe and Mn differed among plant functional types, and this strongly affected litter quality. Resorption efficiencies of N, P and K and accumulation of Ca and Zn increased with decreasing concentrations of these nutrients in green leaves. The N:P, N:K and N:Mg ratios in green leaves predicted resorption proficiency for N, K and Mg, respectively. • Conclusions The results emphasize the fact that nutrient resorption patterns strongly depend on element and plant functional type, which provides new insights into plant nutrient use strategies and nutrient cycling in karst ecosystems.
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BFBNIB, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Drought-associated tree mortality and forest decline have been increasingly observed across the globe due to warmer and drier climates, particularly in drought-prone environments. Understanding how ...forests respond to the increasing inter-annual climate variability and frequent severe drought events in the context of global change is of great significance for predicting the dynamics of forest ecosystems under future warming-drying climate scenarios. This study combined tree-ring series, xylem anatomy, wood isotope signatures, and remote sensing methods to examine the physiological mechanisms underlying the response of natural H. davidii forests in Horqin Sandy Land, a water-limited area in northern China, to the identified severe drought events and long-term climatic variability. Our results indicated that the climatic variables related to environmental moisture conditions exert the most profound influence on the performance of the studied species, with severe drought events significantly reducing growth vigor. The concurrent reduction in water-transporting conductivity and increase in water-use efficiency signified the prevalence of a more conservative water-use strategy in response to severe droughts at the holistic level of the whole tree, which physiologically accounts for the increased hydraulic safety and diminished radial growth during the period. Remotely sensed vegetation indices appeared to respond less conspicuously to severe drought events compared to radial growth, xylem anatomical traits, and water use efficiency. Nonetheless, a coordinated response to climatic variability between tree canopy and individual-level performance was found over the long-term time series, implying that a multiscale approach enhances our comprehension of the long-term forest responses to climatic variability. In short, this study highlights the role of water-related physiology in modulating the performance of H. davidii trees during severe droughts by adjusting xylem hydraulic functioning and tree water use efficiency. The findings lay a theoretical foundation for the use of native tree species for sustainable afforestation in vulnerable sandy land environments.
•Multiple approaches were used to examine Hemiptelea davidii forest responses.•Inter-annual responses to climate at individual and stand levels were coordinated.•Water exerts the strongest influence on forest performance of different levels.•Xylem hydraulics and water use efficiency adjusted significantly during droughts.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•The gasification properties of four cokes were studied by the thermogravimetric analysis.•Component and structural analysis of four cokes were systematically tested.•Microcrystalline structure of ...carbon was an important factor affecting the gasification reactivity.•The single-step global model and distributed activation energy model were used to investigated kinetic characteristic.
This work studied the gasification reaction of four different metallurgical cokes (Coke-A, Coke-B, Coke-C, Coke-D) with CO2 by the thermogravimetric analysis. The physical, chemical and structure features were also analyzed systematically. It is found that with increasing the heating rate, the conversion curves move to high temperature for all these four cokes, and the maximum gasification rate also increases. Meanwhile, at the same heating rate, the gasification reactivity of these four cokes is ordered as: Coke-D > Coke-C > Coke-B > Coke-A. According to the component and structural analysis, the gasification reactivity was mainly due to the microcrystalline structure of the carbon in the coke, and the gasification reactivity of coke increases when the content of amorphous carbon increases. Comparing with the single-step global model, the distributed activation energy model (DAEM) is more accurate to characterize the gasification kinetics for the studied cokes, and the activation energies are in the range of 159.8–254.1 kJ/mol.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Regarding the issue of intense mining pressure appearing in the underlying gateway below the remaining coal pillar in the close‐distance coal seam (the remaining coal pillar is perpendicular to the ...underlying section coal pillar), 401 working face is used as the engineering background. Field measurements, laboratory experiments, numerical simulations, and engineering verification techniques are used to study the abutment pressure's evolution properties and the plastic zone's propagation laws before and after the underlying coal seam roadway experienced the mining impact. The conclusions are as follows: ① The maximum plastic area on the two sides and the roof of the roadway underlying the gob are up to 2 and 1.5 m, whereas the maximum plastic area on the two sides and the roof of the roadway underlying the remaining coal pillar are up to 5 and 4.5 m, respectively. Moreover, the plastic area extends along the two sides, and the section coal pillar is completely broken when the working face is mined below the remaining coal pillar. ② The stress increase coefficient K in the overlap area of the remaining coal pillar and the underlying section coal pillar reaches 3.4 when the mining face penetrates the underlying remaining coal pillar and the advance abutment pressure is overlaid with the concentrated stress of the coal pillar. ③ When the underlying working face is mined to 4, −2, −8, and −14 m away from the remaining coal pillar, the damage range of the roadway 5–10 m ahead increases in turn. At the same time, the maximum plastic area of the roof passes through the plastic area of the upper coal seam floor. Therefore, the underlying and transition areas on both sides of the remaining coal pillar are divided into Area I (15 m) → Area II (the most complicated area to control under the remaining coal pillar, 20 m) → Area III (25 m) according to the width. Furthermore, the divisional differentiated combined control technology of channel steel truss anchor cable with joint double‐way locking control function of roof and coal pillar in Areas I and III, while channel steel truss anchor cable with joint double‐way locking control function of roof and side + high resistance integral door‐type support is proposed in Area II. Field engineering practice shows that the deformation of the roadway surrounding rock can be controlled within 210 mm after adopting the above divisional combined control technology. Finally, the mining operation can safely and efficiently pass through the remaining coal pillar. The research results have important reference values for surrounding rock control of mining roadways in the overlapping area of similar “+”‐type cross‐working face.
Regarding the issue of intense mining pressure appearing in the underlying gateway below the remaining coal pillar in the close‐distance coal seam (the remaining coal pillar is perpendicular to the underlying section coal pillar), 4#–401 working face is used as the engineering background. The evolution characteristics of the abutment pressure and the expansion regulation of the plastic zone before and after the underlying coal seam roadway experienced the mining impact are analyzed using field measurements, laboratory tests, numerical simulations, and engineering verification methods.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
The relationship between eczema, wheeze or asthma, and rhinitis is complex, and epidemiology and mechanisms of their comorbidities is unclear.
To investigate within-individual patterns of morbidity ...of eczema, wheeze, and rhinitis from birth to adolescence/early adulthood.
We investigated onset, progression, and resolution of eczema, wheeze, and rhinitis using descriptive statistics, sequence mining, and latent Markov modeling in four population-based birth cohorts. We used logistic regression to ascertain if early-life eczema or wheeze, or genetic factors (
mutations and 17q21 variants), increase the risk of multimorbidity.
Single conditions, although the most prevalent, were observed significantly less frequently than by chance. There was considerable variation in the timing of onset/remission/persistence/intermittence. Multimorbidity of eczema+wheeze+rhinitis was rare but significantly overrepresented (three to six times more often than by chance). Although infantile eczema was associated with subsequent multimorbidity, most children with eczema (75.4%) did not progress to any multimorbidity pattern.
mutations and rs7216389 were not associated with persistence of eczema/wheeze as single conditions, but both increased the risk of multimorbidity (
by 2- to 3-fold, rs7216389 risk variant by 1.4- to 1.7-fold). Latent Markov modeling revealed five latent states (no disease/low risk, mainly eczema, mainly wheeze, mainly rhinitis, multimorbidity). The most likely transition to multimorbidity was from eczema state (0.21). However, although this was one of the highest transition probabilities, only one-fifth of those with eczema transitioned to multimorbidity.
Atopic diseases fit a multimorbidity framework, with no evidence for sequential atopic march progression. The highest transition to multimorbidity was from eczema, but most children with eczema (more than three-quarters) had no comorbidities.
Chinese sea buckthorn (Hippophae rhamnoides subsp. sinensis) has considerable economic potential and plays an important role in reclamation and soil and water conservation. For scientific cultivation ...of this species across China, we identified the key climatic factors and explored climatically suitable habitat in order to maximize survival of Chinese sea buckthorn using MaxEnt and GIS tools, based on 98 occurrence records from herbarium and publications and 13 climatic factors from Bioclim, Holdridge life zone and Kria' index variables. Our simulation showed that the MaxEnt model performance was significantly better than random, with an average test AUC value of 0.93 with 10-fold cross validation. A jackknife test and the regularized gain change, which were applied to the training algorithm, showed that precipitation of the driest month (PDM), annual precipitation (AP), coldness index (CI) and annual range of temperature (ART) were the most influential climatic factors in limiting the distribution of Chinese sea buckthorn, which explained 70.1% of the variation. The predicted map showed that the core of climatically suitable habitat was distributed from the southwest to northwest of Gansu, Ningxia, Shaanxi and Shanxi provinces, where the most influential climate variables were PDM of 1.0-7.0 mm, AP of 344.0-1089.0 mm, CI of -47.7-0.0°C, and ART of 26.1-45.0°C. We conclude that the distribution patterns of Chinese sea buckthorn are related to the northwest winter monsoon, the southwest summer monsoon and the southeast summer monsoon systems in China.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We explore the interrelationships between the galaxy group halo mass and various observable group properties. We propose a simple scenario that describes the evolution of the central galaxies and ...their host dark matter halos. Star formation quenching is one key process in this scenario, which leads to the different assembly histories of blue groups (group with a blue central) and red groups (group with a red central). For blue groups, both the central galaxy and the halo continue to grow their mass. For red groups, the central galaxy has been quenched and its stellar mass remains about constant, while its halo continues to grow by merging smaller halos. From this simple scenario, we speculate about the driving properties that should strongly correlate with the group halo mass. We then apply the machine learning algorithm the Random Forest (RF) regressor to blue groups and red groups separately in the semianalytical model L-GALAXIES to explore these nonlinear multicorrelations and to verify the scenario as proposed above. Remarkably, the results given by the RF regressor are fully consistent with the prediction from our simple scenario and hence provide strong support for it. As a consequence, the group halo mass can be more accurately determined from observable galaxy properties by the RF regressor with a 50% reduction in error. A halo mass more accurately determined in this way also enables more accurate investigations on the galaxy-halo connection and other important related issues, including galactic conformity and the effect of halo assembly bias on galaxy assembly.
In this paper, we consider a class of SI epidemic model with nonlinear incidence, feedback controls and four different discrete time delays. By skillfully constructing appropriate Lyapunov ...functionals, and combining Lyapunov-LaSalle invariance principle and Barbalat's lemma, the global dynamics of the model are established. Our results extend and improve related works in the existing literatures.
This study aims to explore the relationship between physical exercise (PE), self-control (SC), physical exercise atmosphere (PEA), and mobile phone addiction tendency (MPAT) among Chinese university ...students. Through the quota sampling, 1,433 students complied with the requirements were surveyed from 10 universities in China. PE, SC, PEA, and MPAT were assessed using standard scales. For data analysis, common method deviation test, mean number, standard deviation, correlation analysis and structural equation model analysis were carried out in turn. The results showed PE and MPAT were negatively related (
= -0.158,
< 0.05); PE significantly positively predicted SC (β = 0.082,
= 3.748,
< 0.01), and SC significantly negatively predicted MPAT (β = -0.743,
= -19.929,
< 0.01). Bootstrap method was used to test the mediating effect of SC. The results showed that 95% confidence interval did not include 0. After adding the mediating variable of SC, PE did not significantly negatively predict the tendency of MPAT (β = -0.027,
= -1.257,
> 0.05). The interaction item PEA and SC could significantly positively predict the tendency of MPAT (β = 0.165,
= 2.545,
< 0.05). In the high PEA group, SC had a significant negative predictive effect on the tendency of MPAT (β = -0.665,
= -14.408,
< 0.01); However, in the low PEA group, the negative predictive effect was stronger (β = -0.834,
= -15.015,
< 0.01). The present study shows that PE significantly negatively predicted the tendency of MPAT, and SC played a complete mediating role in the relationship between PE and MPAT; The second half of the indirect effect of PE and MPAT was regulated by the PEA. The PEA will enhance the influence of SC on MPAT, but the high PEA will increase the level of MPAT of individuals at a very high level of SC.
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