Migration Distance Research Articles

High-Value Resource Utilization of Steel Waste to Prepare Uniform Micronano LiFePO4/C Cathode Material.

Steel slag is a promising secondary resource necessitating recycling and high-value utilization. This study innovatively converted steel slag into micronano FePO4 and well-performing LiFePO4/C through a selective two-step leaching process followed by fast coprecipitation in HMCRR under superior mass transfer, and a subsequent in situ carbothermal reduction afterward, thereby realizing a waste-to-resource conversion pathway. Besides, a metal leaching mechanism was proposed based on comprehensive slag composition analysis, affirming the process selectivity. Thermomechanical analysis for precipitation underscored the importance of controlling reaction pH to prevent the formation of impure sediments. Leveraging efficient leaching and superior mass transfer during precursor preparation, the further-made carbon-coated LiFePO4/C derived from steel slag exhibited favorable morphology and enhanced discharge capacity, especially at high rates, owing to fast ion diffusion kinetics, minimized Li+ migration distance, and improved structure stability. Notably, the discharge capacity could reach 167.44, 153.56, and 119.62 mAh/g at 0.1, 1, and 10 C, respectively.

Estimation of the Maximum Migration Distance of a Finite Volume of Light Fluid in a Saturated Porous Medium

Estimation of the Maximum Migration Distance of a Finite Volume of Light Fluid in a Saturated Porous Medium

The Effect Characterization of Lens on LNAPL Migration Based on High-Density Resistivity Imaging Technique

Light non-aqueous phase liquids (LNAPLs), which include various petroleum products, are a significant source of groundwater contamination globally. Once introduced into the subsurface, these contaminants tend to accumulate in the vadose zone, causing chronic soil and water pollution. The vadose zone often contains lens-shaped bodies with diverse properties that can significantly influence the migration and distribution of LNAPLs. Understanding the interaction between LNAPLs and these lens-shaped bodies is crucial for developing effective environmental management and remediation strategies. Prior research has primarily focused on LNAPL behavior in homogeneous media, with less emphasis on the impact of heterogeneous conditions introduced by lens-shaped bodies. To investigate the impact of lens-shaped structures on the migration of LNAPLs and to assess the specific effects of different types of lens-shaped structures on the distribution characteristics of LNAPL migration, this study simulates the LNAPL leakage process using an indoor two-dimensional sandbox. Three distinct test groups were conducted: one with no lens-shaped aquifer, one with a low-permeability lens, and one with a high-permeability lens. This study employs a combination of oil front curve mapping and high-density resistivity imaging techniques to systematically evaluate how the presence of lens-shaped structures affects the migration behavior, distribution patterns, and corresponding resistivity anomalies of LNAPLs. The results indicate that the migration rate and distribution characteristics of LNAPLs are influenced by the presence of a lens in the gas band of the envelope. The maximum vertical migration distances of the LNAPL are as follows: high-permeability lens (45 cm), no lens-shaped aquifer (40 cm), and low-permeability lens (35 cm). Horizontally, the maximum migration distances of the LNAPL to the upper part of the lens body decreases in the order of low-permeability lens, high-permeability lens, and no lens-shaped aquifer. The low-permeability lens impedes the vertical migration of the LNAPL, significantly affecting its migration path. It creates a flow around effect, hindering the downward migration of the LNAPL. In contrast, the high-permeability lens has a weaker retention effect and creates preferential flow paths, promoting the downward migration of the LNAPL. Under conditions with no lens-shaped aquifer and a high-permeability lens, the region of positive resistivity change rate is symmetrical around the axis where the injection point is located. Future research should explore the impact of various LNAPL types, lens geometries, and water table fluctuations on migration patterns. Incorporating numerical simulations could provide deeper insights into the mechanisms controlling LNAPL migration in heterogeneous subsurface environments.

TMOD-14. ESTABLISHING A CLINICALLY RELEVANT MOUSE MODEL TO STUDY NECROSIS AS A PRIMARY VARIABLE IN GLIOBLASTOMA

Abstract All glioblastoma (GBM) molecular subsets share the common trait of accelerated progression following necrosis, which cannot be adequately explained by cellular proliferation arising from accumulated genetic alterations. We suggest that necrosis is much more than a passive phenomenon related to rapid growth but rather is a driving force causing tumor microenvironment (TME) restructuring and biologic progression. yet mechanisms remain poorly understood due to a lack of animal models to study necrosis as a primary variable. In GBM, the most malignant primary brain tumor, vascular pathology and central necrosis precede rapid, radial expansion. To reveal spatio-temporal changes directly following vascular damage in the brain, we developed methodology to induce clinically relevant thrombosis vaso-occlusion within GBMs in immunocompetent RCAS/tv-a mouse model to study TME restructuring by intravital microscopy and demonstrate its impact on glioma progression in real-time. We found that following Rose Bengal photothrombosis, GBMs rapidly expanded radially, with glioma migration away from central necrosis and tumor-associated macrophages (TAMs) and glioma stem cells (GSCs) increased dramatically in the peri-necrotic zones. Through the single cell tracking analysis, we found that TAMs displaying increased displacement toward necrosis and greater overall migration distances. Collectively, this model introduces necrosis as the primary variable and captures glioma growth dynamics and TME restructuring in a manner that will facilitate the development of therapies that antagonize these mechanisms to improve outcomes.

DNAR-01. THERAPEUTIC APPLICATIONS OF MESENCHYMAL STEM CELL LOADED WITH GOLD NANOPARTICLES FOR REGENERATIVE MEDICINE

Abstract In the present study, the various concentrations of AuNP (1.25, 2.5, 5, 10 ppm) were prepared to investigate the biocompatibility, biological performances and cell uptake efficiency via Wharton’s jelly mesenchymal stem cells and rat model. The pure AuNP, AuNP combined with Col (AuNP-Col) and FITC conjugated AuNP-Col (AuNP-Col-FITC) were characterized by Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and Dynamic Light Scattering (DLS) assays. For in vitro examinations, we explored whether the Wharton’s jelly MSCs had better viability, higher CXCR4 expression, greater migration distance and lower apoptotic-related proteins expression with AuNP 1.25 and 2.5 ppm treatments. Furthermore, we considered whether the treatments of 1.25 and 2.5 ppm AuNP could induce the CXCR4 knocked down Wharton’s jelly MSCs to express CXCR4 and reduce the expression level of apoptotic proteins. We also treated the Wharton’s jelly MSCs with AuNP-Col to investigate the intracellular uptake mechanisms. The evidence demonstrated the cells uptake AuNP-Col through clathrin-mediated endocytosis and the vacuolar-type H+-ATPase pathway with good stability inside the cells to avoid lysosomal degradation as well as better uptake efficiency. Additionally, the results from in vivo examinations elucidated the 2.5 ppm of AuNP attenuated foreign body responses and had better retention efficacy with tissue integrity in animal model. In conclusion, the evidence demonstrates that AuNP shows promise as a biosafe nanodrug delivery system for development of regenerative medicine coupled with Wharton’s jelly MSCs.

The underlying causes of differential migration: assumptions, hypotheses, and predictions.

Mechanisms governing the migratory decisions of birds have long fascinated ecologists and sparked considerable debate. Identifying factors responsible for variation in migration distance, also known as differential migration, has been a popular approach to understanding the mechanisms underlying migratory behaviour more generally. However, research progress has been slowed by the continued testing of overlapping, non-mechanistic, and circular predictions among a small set of historically entrenched hypotheses. We highlight the body size hypothesis and suggest that the predictions commonly tested have impeded progress because body size relationships with migration distance are predictions made by several distinct hypotheses with contrasting mechanisms. The cost of migration itself has not been adequately accounted for in most hypotheses, and we propose two flight efficiency hypotheses with time- and energy-minimizing mechanisms that allow individuals to mitigate the risks inherent to longer migrations. We also advance two conceptual versions of the social dominance hypothesis based on two distinct underlying mechanisms related to distance minimization and food maximization that will help clarify the role of competition in driving migratory decisions. Overall, we describe and refine 12 mechanistic hypotheses proposed to explain differential migration (along with several other special-case hypotheses), seven of which have underlying mechanisms related to food limitation as past research has identified this to be an important driver of differential migration. We also thoroughly reviewed 145 publications to assess the amount of support for 10 critical assumptions underlying alternative hypotheses for differential migration in birds. Our review reveals that surprisingly few studies explicitly evaluate assumptions within a differential migration context. Generating and testing strong predictions and critical assumptions underlying mechanisms of alternative hypotheses will improve our ability to differentiate among these explanations of differential migration. Additionally, future intraspecific progress will be greatest if investigators continue to focus on mechanisms underlying variation in migration distance within rather than among demographic classes, as previous research has found differing mechanisms to be responsible for differential migration among demographic classes. Interspecifically, a thorough comparative analysis that seeks to explain variation in migration distance among species would broaden both our understanding of the mechanisms regulating current differential migration patterns and those that led to the evolution of migration more generally. Collectively, we provide a framework that, together with advances in animal-borne tracking and other technology, can be used to advance our understanding of the causes of differential migration distance, and migratory decisions more generally.

Comparative analysis of climate-induced habitat shift of economically significant species with diverse ecological preferences in the Northwest Pacific

The Northwest Pacific Ocean is the most productive fishing ground in the Pacific Ocean, with a continuous rise in water temperature since 1990. We developed stacked species distribution models (SSDMs) to estimate the impacts of climate change on the distribution dynamics of economically significant species under three climate change scenarios for the periods 2040-2060 and 2080-2100. Overall, water temperature is the most important factor in shaping the distribution patterns of species, followed by water depth. The predictive results indicate that all the species show a northward migration in the future, and the migration distance varies greatly among species. Most pelagic species will expand their habitats under climate change, implying their stronger adaptability than benthic species. Tropical fishes are more adaptable to climate change than species in other climate zones. Though limitations existed, our study provided baseline information for designing a climate-adaptive, dynamic fishery management strategy for maintaining sustainable fisheries.

Comediating Adsorption and Electron Transfer via Dual‐Active Site Catalyst Construction for Improving the Treatment of Extraction Wastewater

Solvent extraction is widely applied, while extraction wastewater treatment remains a huge challenge because of the stability of extractants. Heterogeneous Fenton‐like catalysis is a promising method, but the short half‐life of hydroxyl radicals (•OH) generated by hydrogen peroxide (H2O2) activation results in unsatisfactory •OH utilization and organics removal. Herein, an efficient strategy for treating extraction wastewater based on comediating adsorption and electron transfer by fluorine and nitrogen co‐doped carbon (FNC) catalyst with dual‐active site was developed. Specially, N sites adsorb organics and F sites activate H2O2, shortening the migration distance of •OH. Theoretical calculation and di(2‐ethylhexyl) phosphoric acid (D2EHPA) extraction wastewater degradation experiment showed that F site with electron acquisition can transfer electrons provided by electron‐rich D2EHPA enriched at N sites to H2O2, facilitating the continuous generation of •OH through lowering the energy barrier for H2O2 activation. As a result, 96.49% D2EHPA in simulated wastewater and 90.26% total organic carbon in real extraction wastewater were removed. Moreover, FNC catalyst exhibited excellent reusability and ionic adaptability, and can be extended to the removal of various extractants. The proposed dual‐active site catalyst provides an effective strategy for Fenton‐like reaction to treat refractory extraction wastewater, promoting sustainable development of solvent extraction industry.

Research on controllable processing technology of microsphere cavity inside silicon substrates utilizing thermoelectric coupling effect

Micro cavity structures are extensively utilized in semiconductor micro- and nanosensor devices, especially spherical microcavity, whose high Q value not only significantly improves the sensitivity of the sensors, but also enhances their reliability in complex environments. The integration of this structure not only optimizes the performance of the sensor, but also provides the possibility for high-precision detection. In this study, a thermoelectric coupling method for controllable migration of microsphere cavity inside silicon materials is proposed in order to achieve stable formation of the internal microsphere cavity structure. The directional migration mechanism of atoms on the surface of microsphere cavities in silicon substrates under an electric field is explored using a phase field model. The model indicates that changes in the total free energy density induce a solid-gas phase transition on the surface of the microsphere cavity. It is shown that the migration velocity of the microsphere cavity increases proportionally with the electric field strength, and the migration distance increases by approximately 9% for every 10% increase in electric field strength. The migration direction aligns with the direction of the electric field. Simulation results validate the theoretical accuracy, the feasibility of controllable migration by thermoelectric coupling effect in conductive materials through experimental studies. This study provides novel methods and insights for fabricating high-quality spherical cavity in silicon materials and preparing highly sensitive micro- and nanosensor devices.

Geological and hydrological controls on the pressure regime of coalbed methane reservoir in the Yanchuannan field: Implications for deep coalbed methane exploitation in the eastern Ordos Basin, China

The pressure regimes of the No. 2 coalbed methane (CBM) reservoir in the Yanchuannan field located in the southeastern Ordos Basin are highly variable and divided into overpressured (pressure gradient >9.80 kPa/m), slightly underpressured (pressure gradient of 8–9.80 kPa/m), and moderately underpressured (pressure gradient of 5–8 kPa/m). The controlling factors for the variable pressure regimes were investigated through the analysis of geological and hydrological characteristics. The pressure regimes are controlled by different mechanisms in different hydrodynamic environments. In the closed hydrodynamic environment characterized by TDS > 10,000 mg/L and NaCl type of groundwater, the pressure regime is dominated by overpressured to slightly underpressured and is controlled by CBM migration. Overpressure was developed by thermogenic CBM generation during the coalification process and is maintained by thermogenic CBM migration from the extended northwestward and deeply buried CBM reservoir during tectonic uplift. The transition from overpressure to slight underpressure and then to moderate underpressure towards the southeast is the result of the progressively weakened migrated thermogenic CBM with increasing migration distance. In the open hydrodynamic environment characterized by TDS < 10,000 mg/L and NaHCO3 type of groundwater, the pressure regime is dominated by slightly to moderately underpressured and is governed by hydrodynamics. Groundwater is fed by meteoric recharge along the structurally upturned basin margin and creates the hydrodynamic framework during tectonic uplift. The transition from moderate to slight underpressure towards the southwest is associated with the minor decrease range in ground elevation from basin margin to basin interior and the gradually weakened runoff intensity of groundwater with increasing distance to meteoric recharge. The idealized models for the pressure regimes are established, which can provide guidance to deep CBM sweet spot identification in CBM fields in the eastern Ordos Basin and elsewhere.

Evolution of the Caprock Sealing Capacity Induced by CO2 Intrusion: A Simulation of the Dezhou Dongying Formation

CO2–water–rock interactions have an important impact on the stability and integrity of the caprock in CO2 geological storage projects. The injected CO2 in the reservoir enters the caprock via different mechanisms, leading to either the dissolution or precipitation of minerals. The mineral alterations change the porosity, permeability, and mechanical properties of the caprock, affecting its sealing capability. To evaluate the sealing effectiveness of overlying caprock and identify the influencing factors, numerical simulations and experiments were carried out on the mudstone Dongying Formation in Dezhou, China. Based on high-temperature and high-pressure autoclave experiments, batch reaction simulations were performed to obtain some key kinetic parameters for mineral dissolution/precipitation. Then, they were applied to the following simulation. The simulation results indicate that gaseous CO2 has migrated 7 m in the caprock, while dissolved CO2 migrated to the top of the caprock. Calcite is the dominant mineral within 1 m of the bottom of the caprock. The dissolution of calcite increases the porosity from 0.0625 to 0.4, but the overall porosity of the caprock decreases, with a minimum of 0.054, mainly due to the precipitation of montmorillonite and K-feldspar. A sensitivity analysis of the factors affecting the sealing performance of the caprock considered the changes in sealing performance under different reservoir sealing conditions. Sensitivity analysis of the factors affecting the sealing performance of the caprock indicates that the difference in pressure between reservoir and caprock affects the range of CO2 transport and the degree of mineral reaction, and the sealing of the caprock increases with the difference in pressure. Increasing the initial reservoir gas saturation can weaken the caprock’s self-sealing behavior but shorten the migration distance of CO2 within the caprock. When the content is lower than 2%, the presence of chlorite improves the sealing performance of the caprock and does not increase with further chlorite content. This study elucidates the factors that affect the sealing ability of the caprock, providing a theoretical basis for the selection and safety evaluation of CO2 geological storage sites.

Different migration patterns of Wahlberg's eagles Hieraaetus wahlbergi across Africa

Intra‐Africa movements of most African migratory birds remain an enigma. We describe the migrations of Wahlberg's eagle Hieraaetus wahlbergi using GPS‐GSM transmitters on adult eagles in their South African (n = 3) and Kenyan (n = 7) breeding areas between 2018 and 2022. The dataset included 57 migratory tracks, 29 post‐breeding and 28 pre‐breeding. We found long‐distance migrants (LDMs; from South Africa) and short‐distance migrants (SDMs; from Kenya) using common non‐breeding areas centered in the Sudans and Central African Republic. The timing of annual phases was similar, but LDMs departed on their pre‐breeding migration on average later than SDMs (13 August versus 31 July) and arrived later on their breeding grounds (13 September versus 10 August). Conversely, the average departure date on the post‐breeding migration was 4 April for SDM and 23 March for LDMs. LDMs spent significantly less time of the year than SDMs on breeding grounds (44 versus 57%), and slightly but not significantly more time (40 versus 38%) on non‐breeding areas. The post‐breeding migration distance was on average 3413.9 ± 170.9 km for LDMs and 491.9 ± 158.5 km for SDMs. At non‐breeding areas, LDMs reached more northerly latitudes than SDMs, increasing the pre‐breeding migration distance to 4495.9 ± 372.5 km for LDMs versus 1701.9 ± 167.3 for SDMs. Daily flight distances back to the breeding areas averaged 153.4 ± 130.3 km for LDMs and 167.4 ± 122.3 km for SDMs and to non‐breeding areas were shorter for SDMs (124.8 ± 113.0 km) than LDMs (178.0 ± 134.4 km). Migration speed was similar across populations and for pre‐ and post‐breeding migrations. LDMs used more stopover days than SDMs. We conclude that Wahlberg's eagles from different parts of Africa have adapted their migration to differences in timing of the breeding season, distance of travel, and resources in the landscapes encountered during migration.

Diacylglycerol kinase γ facilitates the proliferation and migration of neural stem cells in the developing neural tube.

In this study, we aim to investigate diacylglycerol kinase (DGK) γ expression in developing neural tubes (NTs) and its effects on neural stem cell (NSC) proliferation and migration. Whole-mount in situ hybridization (WMISH) and immunohistochemistry are performed to explore DGKγ localization in developing NTs in vivo. NSCs are treated with sh-DGKγ, R59949, or PMA in vitro. Cell counting kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay and neurosphere formation assay are utilized to evaluate NSC proliferation. Neurosphere migration assay and a transwell chamber assay are used to assess NSC migration. The diacylglycerol (DAG) content is detected via enzyme-linked immunosorbent assay (ELISA). The mRNA expression of DGKγ is detected via quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression levels of DGKγ, protein kinase C (PKC) and phosphorylated PKC (p-PKC) are detected via western blot analysis. The results show that DGKγ mRNA is expressed predominantly in developing NTs. The neuroepithelium in developing NTs is positive for NSC markers, including Nestin, glial fibrillary acidic protein (GFAP), and DGKγ. DGKγ is expressed in the cytoplasm and nucleus of the neuroepithelium and is coexpressed with p-PKCγ and p-PKCδ. The proliferation of NSCs, the number of EdU-positive NSCs, and the number of neurospheres are decreased by sh-DGKγ and R59949 but increased by PMA. There is a shorter migration distance of NSCs and fewer migrated NSCs in the sh-DGKγ, R59949 and PMA groups. DAG content and the p-PKCδ/PKCδ ratio are increased by sh-DGKγ, R59949 and PMA, whereas the p-PKCγ/PKCγ ratio is decreased by PMA. Taken together, our findings indicate that DGKγ facilitates NSC proliferation and migration, which is responsible for the participation of DGK in NT development. DGKγ facilitates NSC migration via the DAG/PKCδ pathway.

Target-Triggered Ultrafast Chondroitin Gelation Enabled Power-Free and Point-of-Care Bioassays.

Point-of-care (POC) tests increasingly highlight the importance of portable, cost-effective, and visually quantitative detection of biomarkers. Herein, we developed a power-free and visual signal-readout POC sensor based on the target-triggered ultrafast gelation process. In the gelation process, the target triggered the cascade reaction catalyzed by oxidase and ferrous glycinate to produce carbon radicals that immediately initiated the rapid polymerization and cross-linking of acryloylated chondroitin sulfate and dimethylacrylamide. This highly efficient enzymatic polymerization process contributed to the ultrafast generation of chondroitin hydrogel within 1 min at 25 °C. The increase in viscosity of aqueous solution resulted from hydrogel formation was then visually measured according to the distance of solution migration on a tick-labeled pH test strip, which thus realized the quantification of a target. By utilizing glucose oxidase as an oxidase model during the gelation process, this POC sensor was successfully employed in the rapid quantitative detection of glucose without the need for any auxiliary instruments. Benefiting from the specificity and stability of the enzymatic polymerization reaction, the sensor exhibited excellent performance in the detection of glucose in clinical blood samples. Moreover, the sensor was further extended to uric acid detection and enabled accurate assay in clinical urine samples, which indicated the versatility and practicability of this sensor in the POC test.

Is sexual size dimorphism in walleye, Sander vitreus, a driver of seasonal movements in Lake Erie?

Walleye (Sander vitreus) are a sexually dimorphic species in which females are larger than males in adulthood. Walleye can also exhibit sex- and population-based differences in migration behavior. In Lake Erie, we used acoustic telemetry to test the prediction that female walleye exhibit larger broad-scale movements than males during the summer and autumn. This prediction was based on the hypothesis that greater foraging in females would be needed to satisfy their higher energy requirements. We quantified movements of males and females from distinct spawning populations from Lake Erie's west and east basins using a lake-wide grid of acoustic receivers in 2017 and 2018. We found no differences between male and female home range sizes, core range sizes, or distances travelled in either population. Fish length-at-tagging was unrelated to the size of a fish's home range or to its distance travelled, contrary to previous predictions about body size as a driver of migration distance in the Lake Erie population. We found that west basin walleye occupied large and indiscrete portions of the lake, but the core range of females extended into the central basin, whereas males were concentrated in the west basin. Walleye originating from the east basin confined their movements primarily to the east basin and showed stronger home range overlap among members of their population than did walleye from the west basin population. Within either population, walleye had more home range overlap with members of the same sex, which likely reflects differences in the migratory tendencies of males and females.

Oxidative state is associated with migration distance, but not traits linked to flight energetics

Flight can be highly energy demanding, but its efficiency depends largely on flight style, wing shape and wing loading, and a range of morphological and lifestyle adaptations that can modify the cost of sustained flight. Such behavioural and morphological adaptations can also influence the physiological costs associated with migration. For instance, during intense flight and catabolism of reserves, lipid damage induced by pro‐oxidants increases, and to keep oxidative physiological homeostasis under control, the antioxidant machinery can be upregulated. Studies on the oxidative physiology of endurance flight have produced contradictory results, making generalization difficult, especially because multispecies studies are missing. Therefore, to explore the oxidative cost of flight and migration, we used samples collected during the breeding season from 113 European bird species and explored the associations of measures of antioxidant capacity (total antioxidant status, uric acid and glutathione concentration) and oxidative damage of lipids (malondialdehyde) with variables reflecting flight energetics (year‐round or specifically during migration) using a phylogenetic framework. We found that none of the traits predicting year‐round flight energy expenditure (flight style, wing morphology and flight muscle morphology) explained any measures of oxidative state. Our results suggest that birds endure their everyday flight exercise without or with low oxidative cost. However, oxidative damage to lipids and one component of the endogenous antioxidant system (uric acid), measured after the end of spring migration on breeding adult birds, increased with migration distance. Our results suggest that migration could have oxidative consequences that might be carried over to subsequent life‐history stages (breeding).

Multifactorial Analysis of the Effect of Applied Gamma-Polyglutamic Acid on Soil Infiltration Characteristics

To investigate the mechanism and influence of applying gamma-polyglutamic acid (γ-PGA) on soil water infiltration, laboratory experiments and numerical simulations were conducted using Hydrus-1D. These studies assessed the impact of various application rates of γ-PGA on soil water characteristic parameters. Orthogonal simulation experiments on soil bulk density, γ-PGA application rates, and burial depths were performed utilizing predefined soil water characteristic values (twelve groups: nine groups of numerical simulation experiments and three groups of laboratory verification tests), and the soil infiltration characteristics were analyzed. Concurrently, an empirical model was developed to elucidate the relationships between the empirical model parameters and influencing factors, as well as to examine the sensitivity of these factors to changes in soil infiltration rate. The relationship between cumulative infiltration and the distance of wetting front movement, based on the water balance equation, was refined. The results indicated that γ-PGA significantly affected soil water characteristic parameters, where the saturated water content and the reciprocal of soil intake suction increased with rising γ-PGA applications (p &lt; 0.01), while the saturated hydraulic conductivity and the parameter n decreased (p &lt; 0.01), with no notable changes in the retained water content (p &gt; 0.05). The trend in cumulative infiltration influenced by various factors could be modeled by a capacitive charging model function, which yielded a superior fit. A negative correlation existed between the sensitivity index and all the influencing factors (p &lt; 0.05), with the order of influence being soil bulk density, γ-PGA application rate, and γ-PGA burial depth, respectively. Utilizing the modified water balance equation, the ratio of cumulative infiltration to wetting front migration distance corresponded more closely with a power function. These findings provide a theoretical foundation for further studies on the effects of γ-PGA on crop growth characteristics in fields and the optimization of γ-PGA technical element combinations.

Spatial and Temporal Change Analysis of Urban Built-Up Area via Nighttime Lighting Data—A Case Study with Yunnan and Guizhou Provinces

As urbanization accelerates, characteristics of urban spatial expansion play a significant role in the future utilization of land resources, the protection of the ecological environment, and the coordinated development of population and land. In this study, Yunnan and Guizhou provinces were selected as the study area, and the 2013–2021 National Polar-Orbiting Partnership’s Visible Infrared Imaging Radiometer Suite (NPP-VIIRS) nighttime light (NTL) data were utilized for spatial and temporal change analysis of urban built-up areas. Firstly, the built-up areas in Yunnan and Guizhou provinces were extracted through ENUI (Enhanced Nighttime Lighting Urban Index) indices, and then the urban expansion speed and urban center of gravity migration were constructed and used to explore and analyze the spatial and temporal change and expansion characteristics of built-up areas in Yunnan and Guizhou provinces. The results showed the following. (1) Due to the complementarity between data types, such as NTL, EVI, NDBI, and NDWI, ENUI has better performance in expressing urban characteristics. (2) Influenced by national and local policies, such as “One Belt, One Road”, transportation infrastructure construction, geographic location, the historical background, and other factors, the urban expansion rate of Yunnan and Guizhou provinces in general showed a continuous advancement from 2013 to 2021, and there were three years in which the expansion rate was positive. (3) The center of gravity migration distance of most cities in Guizhou Province shows a trend of increasing and then decreasing, while the center of gravity migration distance in Yunnan Province shows a trend of continuous decrease in general. From the perspective of migration direction, Guizhou Province has the largest number of migrations to the northeast, while Yunnan Province has the largest number of migrations to the southeast. (4) Influenced by policy, economy, population, geography, and other factors, urban compactness in Yunnan and Guizhou provinces continued to grow from 2013 to 2021. The results of this study can help us better understand urbanization in western China, reveal the urban expansion patterns and spatial characteristics of Yunnan and Guizhou provinces, and provide valuable references for development planning and policymaking in Yunnan and Guizhou provinces.

Characteristics of Rock Avalanche Deposit in Wangjiapo, Ludian Based on UAV Aerial Image Recognition

Rock avalanche disasters in alpine and gorge regions are frequent and large in scale and cause severe damage. The movement of a rock avalanche is complex and has not been fully studied. The deposits of a rock avalanche can provide valuable insights into its movement process, which is crucial in understanding the rock fragmentation mechanism and predicting disaster-affected areas. Taking the Wangjiapo rock avalanche in Yunnan Province of China as an example, the size, shape and distribution characteristics of the deposit were analyzed based on field surveys, unmanned aerial vehicle (UAV) photography and image recognition technology. Initially, 3062 deposited rock blocks were manually measured in the field. Subsequently, the Particles/Pores and Cracks Analysis System (PCAS) was employed to identify 11,357 rock blocks with an area greater than 0.1 m2 from UAV orthophotos. By comparing the characteristics of the rock blocks obtained through image recognition and manual measurement, the statistical analysis of UAV aerial imagery combined with PACS proved feasible in studying the Wangjiapo rock avalanche. The results showed that the rock block movement was accompanied by fragmentation and sorting processes; furthermore, the roundness increased with the migration distance. Small blocks were more prevalent at the foot of the slope, while irregularly shaped, large blocks dominated in source areas. The movement of huge blocks was characterized by significant potential energy-driven features and inertia advantages, allowing them to travel farther than smaller blocks, and they tended to be concentrated in the central area of the deposit. Additionally, affected by the cementation degree of breccia and the topography, the blocks in the eastern and western deposit areas exhibited different fragmentation and deposition characteristics.

Avian diversity across guilds in North America versus vegetation structure as measured by the Global Ecosystem Dynamics Investigation (GEDI)

Avian diversity, a key indicator of ecosystem health, is closely related to canopy structure. Most avian diversity models are based on either optical remote sensing or airborne lidar data, but the latter is limited to small study areas. The launch of the Global Ecosystem Dynamics Investigation (GEDI) instrument in 2018 has opened new avenues for exploring the influence of vegetation structure on avian diversity. To examine how direct measurements of canopy structural characteristics explain bird diversity across North America, we analyzed 18 GEDI metrics from 2019 to 2022, along with corresponding Breeding Bird Survey (BBS) counts and AVONET morphological data, analyzing effects across broad regions and at varying spatial extents. We grouped 440 bird species into 20 ecological guilds under six guild categories and employed random forest algorithms to model avian diversity across eight spatial extents (1, 2, 3, 4, 5, 10, 20, and 39.2 km). The models predicted six diversity indices, including species richness (sRich), functional richness (fRich), evenness (fEve), dispersion (fDis), divergence (fDiv), and redundancy (fRed) across eight spatial extents. The best-predicted guilds varied for each diversity index. The most accurate models were sRich (pseudo-R2 = 0.71, RMSE = 4.28) and fRed (pseudo-R2 = 0.60, RMSE = 0.13) for forest specialists guilds; fRich (pseudo-R2 = 0.55, RMSE = 0.18) for urban guilds; fEve (pseudo-R2 = 0.28, RMSE = 0.08) for insectivore guilds; and fDiv (pseudo-R2 = 0.38, RMSE = 0.12) and fDis (pseudo-R2 = 0.53, RMSE = 0.87) for short distance migrants guilds. Our results highlight the critical role of canopy structure, including its horizontal and vertical distribution and variation, in predicting avian diversity, as measured by the mean number of detected modes (num_detectedmodes), the standard deviation of foliage height diversity (FHD), num_detectedmodes, canopy cover, and plant area index (PAI) across the spatial extents centered on BBS routes. Therefore, we recommend incorporating the GEDI metrics into avian diversity modeling and mapping across North America, thereby potentially enhancing bird habitat management and conservation efforts.