Search

Changes in land use and landscapes have a direct impact on the regional eco-environment. It is of great importance to understand the change pattern of land use, landscapes, and their mechanism on the ecological quality, especially ecologically fragile areas. The northern sand-prevention belt (NSPB) is an important ecologically fragile area in China, which has a large influence on the ecological security of the entire country. Based on the land use data of the NSPB in 2000, 2010, and 2018, we studied the spatio-temporal characteristics of land-use change and change in landscape patterns. The ecological quality represented by the remote sensing-based desertification index (RSDI) was calculated using satellite images. The effects of land use and landscape patterns on RSDI were analyzed by geographic detector and geographically weighted regression. Important results include the following: (1) Land-use change in the study area was high during 2000–2010 but slower in 2010–2018. Grassland was the largest land-use type in the NSPB, and varied greatly in terms of total change and spatial location. The major change was the conversion between dense and moderate grass, with 64,860 km2 of dense grass turning into moderate grass, and 48,505 km2 changing the other way. (2) Among the four landscape metrics, patch density, area-weighted mean fractal dimension, and edge density increased, whereas the aggregation index decreased, which indicated that the landscape was developing towards heterogeneity, fragmentation, complexity, and aggregation. Spatially, the landscape metrics presented a strip distribution in the east of the NSPB. (3) The effects of various land-use types on ecological quality, from high to low, were unused land, woodland, dense grass, cropland, moderate grass, built-up land, sparse grass, and waterbody. The areas where the ecological quality was greatly affected by the landscape patterns were concentrated in the agro-pastoral ecotone and the forest-steppe ecotone. The results of this study reveal the trends of land use and landscape patterns in the NSPB over 18 years and can help to understand their mechanism on ecological quality, which is of significance for the management of this area. • LUC in the NSPB was active from 2000 to 2010 and weakened from 2010 to 2018. • The landscape was developing towards heterogeneity, fragmentation, complexity, and aggregation. • The effects of land use and landscape on ecological quality were studied by GD and GWR. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we estimate the size of ''s in the famous L. Zalcman''s lemma. With it, we obtain some uniqueness theorems for meromorphic functions f and when they share two transcendental meromorphic functions. [Copyright &y& Elsevier]

Abstract: Students’ learning has been the center of schooling. This study examined the contribution of situational interest motivation and cognitive engagement in workbooks to student achievement in learning health-related fitness knowledge. Situational interest, performance on solving workbook problems, and knowledge gain in cardio-respiratory fitness and benefits were measured in 670 third-grade students from 13 randomly selected urban elementary schools. Structural equation modeling and regression curve estimation analyses revealed that situational interest contributed little to workbook performance and knowledge gain. Performance on solving workbook problems contributed significantly to knowledge gain. The results also show that skipping workbook tasks had stronger negative impact on knowledge gain than performing the tasks incorrectly, suggesting the importance of engaging students in the learning process by attempting the workbook tasks. The findings reinforced the value of using workbooks to facilitate cognitive knowledge learning in physical education, but raised questions about the direct function of situational interest on engaging students in cognitive learning. [Copyright &y& Elsevier]

The purpose of this study was to examine individual and situational interests in learning motor skills as associated with gender and skill. Individual and situational interests and motor skill were measured in middle school girls (n = 109) and boys (n = 82). A correlation analysis for the entire sample showed a moderate correlation between skill and individual interest (r = .63) and weak relationships between individual and situational interest (r < .10) and between situational interest and skill (r < .18). A MANOVA analysis revealed a difference between the boys and girls in situational interest at a borderline significance level (p = .05). However, when individual interest, skill, and gender were compared between students with high or low situational interest in a hierarchical log linear model, it was found that both groups did not differ in number of boys and girls (p = .98). But the high situational interest group had more students with high skill (p = .001) and high individual interest (p = .02). The results suggest that discrepancies in acquired skill accounted for the gender difference and that acquired skill is associated with individual interest and high situational interest in learning motor skills. [Copyright &y& Elsevier]

Cell-in-cell structure is prevalent in human cancer, and associated with several specific pathophysiological phenomena. Although cell membrane adhesion molecules were found critical for cell-in-cell formation, the roles of other membrane components, such as lipids, remain to be explored. In this study, we attempted to investigate the effects of cholesterol and phospholipids on the formation of cell-in-cell structures by utilizing liposome as a vector. We found that Lipofectamine-2000, the reagent commonly used for routine transfection, could significantly reduce entotic cell-in-cell formation in a cell-specific manner, which is correlated with suppressed actomyosin contraction as indicated by reduced β-actin expression and myosin light chain phosphorylation. The influence on cell-in-cell formation was likely dictated by specific liposome components as some liposomes affected cell-in-cell formation while some others didn't. Screening on a limited number of lipids, the major components of liposome, identified phosphatidylethanolamine (PE), stearamide (SA), lysophosphatidic acid (LPA) and cholesterol (CHOL) as the inhibitors of cell-in-cell formation. Importantly, cholesterol treatment significantly inhibited myosin light chain phosphorylation, which resembles the effect of Lipofectamine-2000, suggesting cholesterol might be partially responsible for liposomes' effects on cell-in-cell formation. Together, our findings supporting a role of membrane lipids and cholesterol in cell-in-cell formation probably via regulating actomyosin contraction. [ABSTRACT FROM AUTHOR]

Aboveground biomass (AGB) in grasslands directly reflects the net primary productivity, making it a sensitive indicator of grassland resource quality and ecological degradation. Accurately estimating AGB over large regions to reveal long-term AGB evolution trends remains a formidable challenge. In this study, we divided Inner Mongolia Autonomous Region (IMAR) grasslands into three study regions based on their spatial distribution of grassland types. We combined remote sensing data with ground-based sample data collected over the past 19 years from 6114 field plots using the Google Earth Engine platform. We constructed random forest (RF) and traditional regression AGB inversion models for each region and selected the best-performing model through accuracy assessment to estimate IMAR grassland AGB for the period 2000–2022. We also examined the trends in AGB changes and identified the driving forces affecting IMAR grasslands through the application of Theil-Sen estimation, Mann-Kendall trend analysis, and the Geodetector model. The main findings are as follows: (1) Compared with the univariate parametric traditional regression model, the AGB monitoring accuracy of the multivariate non-parametric RF model in the three study regions increased by 5.94%, 5.08% and 19.14%, respectively. (2) The average AGB per unit area of IMAR grasslands from 2000 to 2022 was 731.41 kg/hm2, with alpine meadow having the highest average AGB (1271.70 kg/hm2) and temperate grassland desertification having the lowest (469.06 kg/hm2). IMAR grasslands exhibited an overall increasing trend in AGB over the past 23 years (6.01 kg/hm2•yr), with the increasing trend covering 83.52% of the grassland area and the decreasing trend covering 16.48%. (3) Spatially, IMAR grassland AGB showed a gradual decline from northeast to southwest and exhibited an increasing trend with increasing longitude (45.423 kg/hm2 per degree) and latitude (71.9 kg/hm2 per degree). (4) Meteorological factors were the most significant factors affecting IMAR grassland AGB, with precipitation (five-year average q value of 0.61) being the most prominent. In the western part of IMAR, where precipitation is consistently limited throughout the year, the primary drivers of influence were human activities, with particular emphasis on the number of livestock (with a five-year average q value of 0.44). It is evident that reducing human activity disturbance and pressure in fragile grassland areas or implementing near-natural restoration measures will be beneficial for the sustainable development of grassland ecosystems. The results of this research hold substantial reference importance for the protection and restoration of grasslands, the supervision and administration of grassland resources, as well as the development of policies related to grassland management. [Display omitted] • The aboveground biomass (AGB) of grasslands in IMAR increased over the past 23 years. • IMAR grassland AGB shows an upward trend with increasing longitude and latitude. • Precipitation is the main factor affecting grassland AGB in IMAR. • Human activities have a greater impact on the grassland AGB in western IMAR. [ABSTRACT FROM AUTHOR]

Dissipation, residues and risk assessment of lufenuron during kumquat growing and kumquat processing were investigated under field and household conditions. The QuEChERS technique with high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used to detect lufenuron residues content in kumquats and its processed products. The recoveries were 82.3–102.8% at a spike level of 0.005–0.5 mg kg−1, the relative standard deviations (RSDs) were 1.1–9.4%. The dissipation kinetics data showed that lufenuron in kumquats were degraded with the half-lives of 9.12–12.60 days. The terminal residues of lufenuron in kumquats were 0.064–0.107 mg kg−1 after application one times with a pre-harvest interval (PHI) of 14 days under the designed dosages. The juicing process can significantly reduce the residues of lufenuron in kumquats juice, and the processing factor (PF) value of juicing process was 0.15. The chronic dietary exposure assessment risk quotient (RQ) values of lufenuron in kumquats fruit and juice for different consumers were 0.71–2.13% and 0.37–0.86%, all of the RQ values were lower than 100%. The results from this study are important reference for Chinese governments to develop criteria for the safe and rational use of lufenuron on kumquats and monitor the quality safety of agricultural products and protecting consumer health. • Residue behaviorof lufenuron in kumquats during growing and processing is reported for the first time. • The degradation half-life of lufenuron showed that lufenuron degrades relatively slowly. • The juicing process can significantly reduce the residues of lufenuron in kumquats juice. • Dietary exposure risks associated with lufenuron in kumquats fruit and juice in China are all not a health concern. [ABSTRACT FROM AUTHOR]