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Size segregation will lead to stratification of a particle system. At present, people have not fully understood the segregation mechanism. In this work, we have studied the size segregation behavior of two-component disk particles in chute flows. The effects of particle size ratio η, particle density ρ, static friction coefficient μ and chute angle α on size segregation are discussed. We use the discrete element method to simulate and calculate the force of disk large particles during segregation. Results show that the 'squeeze expulsion' mechanism plays a key role in the size segregation of a disk particle flow. We establish a physical model of 'squeeze expulsion' of disk particles and obtain the conditions for the formation of 'squeeze expulsion' mechanism. [ABSTRACT FROM AUTHOR]

Resource availability pre‐hibernation and post‐hibernation may be crucial phases for the survival of hibernators. However, the effects of grazing on food availability in pre‐hibernation and on the winter survival of hibernating rodents remains unstudied. The objective of this study was to investigate the effects of domestic sheep grazing on northern three‐toed jerboa (Dipus sagitta) populations pre‐, post‐, and during hibernation. We conducted a grazing exclusion experiment with randomized complete block design in the Alxa Desert, Inner Mongolia, China, from April to October 2006 to 2011. We live‐trapped jerboas in 3 grazed plots and 3 ungrazed plots. We measured the quantity of vegetation in grazed and ungrazed plots to determine the relationship between jerboas and plant food resources. We observed higher jerboa densities both pre‐ and post‐hibernation, and heavier individual body mass pre‐hibernation, in ungrazed sites. More food availability contributed to higher jerboa body mass in ungrazed areas during pre‐hibernation, and attracted more jerboas immigrating to ungrazed areas during the post‐hibernation period. These results demonstrate that grazing negatively affects the northern three‐toed jerboa population by adjusting food availability pre‐ and post‐hibernation; survival rates were not affected by grazing. © 2018 The Wildlife Society. Grazing exclusion is beneficial for northern three‐toed jerboas by providing increased total food biomass and preferred food biomass before and after hibernation. In grassland management, excluding livestock in overgrazed areas may contribute to an increase in the northern three‐toed jerboa population. To achieve an ecological balance between grass, northern three‐toed jerboa, and livestock, it is necessary to adjust the traditional grazing strategy before and after hibernation in the Alxa Desert. [ABSTRACT FROM AUTHOR]

Rodent pest population outbreaks occur frequently in grassland ecosystems in northern China. The Mongolian gerbil ( Meriones unguiculatus) is a dominant pest rodent which is distributed across the semi-desert grasslands of Inner Mongolia, China. In 2009, we studied the contraceptive effect of levonorgestrel-quinestrol (EP-1), concentration 50 ppm, on a wild Mongolian gerbil population. The one-off contraceptive treatment was compared with a control group using a semi-monthly live trapping method in the Ordos Semi-desert Grassland Region of Inner Mongolia. The results show that juveniles were not recruited in spring in the treatment group. Ratios of juveniles in the control and treatment groups showed significant semi-monthly differences from spring to summer (one-way ANOVA, F2, 14= 7.53, P < 0.05). Between both groups, annual fluctuations of juvenile and total population densities were significantly different respectively ( F2, 14= 4.64, P < 0.05; F2, 18= 7.72, P < 0.05). The contraceptive EP-1 delayed the normal reproductive pattern of Mongolian gerbil populations. This suppressed birth rates of gerbil populations, reduced their densities, and changed their age structures. The period of EP-1 baiting should be extended but it could be an ideal method for controlling Mongolian gerbil populations during each breeding season. [ABSTRACT FROM AUTHOR]

Environmental stressors and disturbances can cause changes in an ecosystem's community structure, which can be reflected in its functional diversity. As grazing intensity increases, this causes changes in the environment that inevitably lead to changes in the community structure, which can especially affect rodents due to their sensitivity to the environment. The effects of grazing prohibition and overgrazing on the functional diversity of desert rodent communities in Alxa were studied in April, July, and October of 2018–2020. The trap‐day method was used to study rodent communities in disturbed habitats. Five functional traits were selected and quantified: nutrition, life history, physiology, morphology, and activity rhythm. The results showed that: (1) The species composition of rodent communities in the Alxa Desert in spring and autumn was significantly correlated with the functional traits of the hibernation, reproductive cycle, and feeding habits. The species composition in the summer was only significantly correlated with the functional traits of reproductive cycle and diet. (2) The effects of overgrazing on the functional diversity of rodents in desert areas have significant temporal and spatial characteristics. (3) In spring and summer, overgrazing made the Functional Richness index of the rodent community lower than that of areas where grazing is prohibited, but the Functional Evenness index was higher than that of grazing‐prohibition areas. In autumn, overgrazing increased the Functional Richness index of the rodent community and decreased the Functional Evenness index. The Functional Divergence index was higher in overgrazing areas than in grazing‐prohibited ones. These results suggest that, in spring and summer, overgrazing reduced the ecological space utilization ability of rodent communities; however, the impact on the degree of utilization of community resources is more comprehensive. In autumn, overgrazing increases the ability of rodent communities to use ecological space but reduces resource efficiency. Overgrazing makes the niche differentiation of rodent communities higher, the degree of overlap lower, and the competition between species weaker. Therefore, overgrazing will affect the functional diversity of the community through the utilization of ecological space, resource utilization, interspecific competition, and niche. [ABSTRACT FROM AUTHOR]

Grassland is not only an important part of the terrestrial ecosystem with multiple ecological functions, but also an important base for Chinese herdsmen to produce and live. However, the occurrence and spread of rodent infestation reduces the biodiversity and productivity of grassland ecosystems. It also severely threatens human life, health, and biosecurity through disease transmission. In this study, we explored the ability of the nanocomposite sterilant ND-1 to control grassland rodent populations. Semi-closed experimental and control plots were established in the desert area of Alashan, Inner Mongolia, China. In spring 2018, the nanocomposite sterile ND-1 (Nongda-1) was introduced once, and the control effect of ND-1 on the growth of the wild population of midday gerbils was measured for two years. We show that ND-1 significantly reduced the population of midday gerbils in the experimental area, with a negative population growth rate. In addition, in the second year, the ratio of female midday gerbils to sub-adults in the experimental area was significantly lower than that in the control area, which resulted in a significant difference in the sex ratio of midday gerbils. There were significantly fewer females than males, and the population growth of midday gerbils in the experimental area was significantly inhibited. ND-1 had no significant effect on the home range of midday gerbils, and sterile individuals continued to occupy the home range and consume resources. Therefore, ND-1 reduced the number of female midday gerbils during the breeding period and the sex ratio and population density and altered the age structure of the wild population. Additionally, competition between sterile and normal individuals had a significant control effect on the growth of wild populations. Our studies demonstrate the significance of ND-1 in the sustainable control of grassland rodent pests, with the potential for limiting grassland rodent damage in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel DEM-based method to simulate granular flow with dust effectively. • A model of granule equivalent friction coefficient and dust effect is established. • Simulation and experiment results appear equal changes following dust contents. The simulation of dust-bearing granular accumulation flow in the theoretical and practical aspects of the engineering field poses a significant challenge due to the massive computational requirements associated with cross-scale simulations. In this study, a novel approach is proposed to address this issue by developing a model that accounts for the impact of dust on granular flow through changes in the granule friction coefficient. Initially, the theoretical analysis was conducted to examine the effects of dust on granular flow. Subsequently, a method was developed to measure the equivalent friction coefficient of granules by combining theoretical analysis and experimental work. The proposed method was then employed to simulate the stability of a spherical granule pile in a drum influenced by dust content and compared against experimental results. The simulation results demonstrate agreement with the experimental results, indicating the feasibility of modeling the effect of dust on dust-bearing granular flow through the granule equivalent friction coefficient. The dust effect can be considered equivalent to a change in the granule friction coefficient, which facilitates the reduction of the computational load generated by the Discrete Element Method (DEM) method and enables cross-scale simulations. [ABSTRACT FROM AUTHOR]

Sedimentological and chronological analyses of coastal dunes can determine their sedimentation processes and yield information that can reflect changes in local marine environments (e.g., information on climate, biology, and sea‐level changes in tectonically stable areas). In this study, Late Quaternary deposits on Shidao Island, one of the Xisha Islands, South China Sea, were analysed using techniques such as U/Th dating to obtain the following results: (1) Four lithofacies associations and two unconformities were identified from the deposits on Shidao Island. On this basis, the Shidao Island sediments can be divided into three stages of aeolian sediments and one stage of beach rock sediments. (2) U/Th dating revealed that the aeolian deposits on Shidao Island formed during three periods, namely, marine isotope stages 5.2, 5.1, and 4, and that the beachrocks were formed in the Holocene when the sea level rose to its present height. (3) The aeolianites on Shidao Island all formed in an environment in which the sea level was relatively stable or slowly falling. This study determined for the first time the specific sedimentary ages of the aeolianites on Shidao Island, and reconstructed the sedimentation process of the deposits on Shidao Island based on palaeo‐sea‐level changes. These results can provide more reliable geochronology data for the future study of Late Quaternary marine environments across the East Asian region. [ABSTRACT FROM AUTHOR]

The moving granular filter technology based on size segregation is a promising technology for hot gas cleanup. A moving granular bed that can separate a mixture of particles spontaneously and replace the particles continuously layer by layer was design in this work. We experimentally studied the effects of free slope length (L), particle replacement rate (Q), and inlet large particle mass fraction (α) on the degree of size segregation. Results showed that the degree of size segregation increased with an increase in L and decreased with an increase in α. Q exerted little effect on size segregation. The control of the layer thickness and flow velocity of the particles after segregation was achieved by changing α and the angle of the movable plate (θ). We also captured the size segregation process of the particles with a camera and analyzed the influence mechanisms of L , Q , and α on size segregation. [Display omitted] • The velocity distribution of particles on the chute was obtained. • The control of the layer thickness and flow velocity of the particles was realized. • Size segregation depended on the coupling of kinetic sieving and squeeze expulsion. [ABSTRACT FROM AUTHOR]

High-temperature dust removal is one of the important procedures for integrated coal gasification combined cycle. In this work, a moving granular bed filter that can separate the mixture of particles of different sizes spontaneously was designed. We studied the flow characteristics of binary particles in the filter based on the discrete element method (DEM). We gave the formation process of the boundary between the stationary layer and the flowing layer, which should have a reference value for the control of the stationary layer and the design of the filter inclined groove. Typical separation trajectories of large and small particles during size segregation were also given. The degree of size segregation decreased with the increase of the mass flux of particles. Real-time control of the large particle layer thickness in the filter area can be achieved by changing the mass fraction of the inlet large particles. [Display omitted] • The spontaneous separation of particle mixtures of different sizes was realized. • The formation process of stationary layer and the flowing layer was given. • Real-time control of the large particle layer thickness in the filter was achieved. [ABSTRACT FROM AUTHOR]

False zokor (Myospalax aspalax) is one of the subterranean rodents distributed in East Asia. Molecular data and demography ofM. aspalaxare unknown, and the population management is difficult, because it is specialized for underground life. In this study, the complete mitochondrial DNA genome ofM. aspalaxwas determined. The results suggested that the mitogenome was 16,436 bp in length, and consisted of 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one displacement loop. The overall base composition of the heavy strand was A 33.40%, T 29.34%, C 24.90%, and G 12.36%, with A + T > C + G.Myospalax aspalaxis a sister to the genusMyospalax,and have a most closely relationship withM. psilurus. The mitogenome data are potentially important for population management ofM. aspalaxand should contribute to the interspecies comparative analyses of genusMyospalax. [ABSTRACT FROM AUTHOR]