Surface Depth Research Articles

Tropical cyclone effects enhance limnetic plankton trophic‐level relationships in a subtropical oligotrophic freshwater ecosystem

Abstract Tropical cyclones (TCs), as natural extreme weather events, alter plankton and hydrological environments, affecting the stability of biological processes in freshwater ecosystems, and such TC effects vary with water depths. Previous studies have found increased phytoplankton biomass resulting from TC effects has been observed, leading to potential strong grazing of zooplankton and enhanced plankton trophic‐level relationships. However, this remains understudied, particularly under in situ conditions. Using a zooplankton to phytoplankton (ZB/PB) ratio to represent the plankton trophic‐level relationship, we estimated the ZB/PB ratios at various depth intervals, including surface (2 m depth) and euphotic (depths between 0 and 20 m) depths and depth layer 0–50 m (depths between 0 and 50 m), in a subtropical deep oligotrophic freshwater ecosystem from 2012 to 2015 to understand how TC effects would influence changes in the ZB/PB ratio variations. TCs affected the surface and euphotic ZB/PB ratios but not those at the depth layer 0–50 m. The TC durations had an initially negative and then positive impact on the surface ZB/PB ratio, indicating that slow‐moving TCs might restructure surface plankton trophic‐level relationships. The water temperature and nutrient dynamics during the TC weeks showed the highest correlations with the ZB/PB ratios at the surface and euphotic depths. The combined environmental effects influenced the ZB/PB ratios at the surface and euphotic depths during the TC weeks, with 65.1% and 72.2% of the total variations explained in the multivariate regressions, respectively. There were greater impacts of TCs in shallow water (surface and euphotic depth) than in deep water. Aquatic food chains may be unexpectedly vulnerable to natural extreme weather events, such as TCs, and continuous assessments of food chain dynamics are necessary to better manage potential risks from natural extreme weather events in freshwater ecosystems.

Effect of alkali and alkaline-earth metal oxides on the chemical strengthening properties of sodium alumino-silicate glasses

Silicate based alumino-sodium (SAS) glasses were fabricated with various alkali (Li2O and K2O) and alkaline-earth metal (MgO and CaO) oxides to study their influence on chemical strengthening characteristics such as surface compression stress (CS) and depth of layer (DOL) after ion exchange of Na+ with K+. Introducing Li2O instead of Na2O decreased DOL while increasing CS up to 5.0 mol. % of Li2O. In contrast, replacing Na2O content with K2O increased DOL while decreasing CS. When alkaline-earth oxides such as MgO and CaO were substituted for Na2O, both CS and DOL decreased. Micro-Raman spectroscopy was used to study structural changes induced by alkali and alkaline-earth oxides and their impact on ion exchange properties. The inter-diffusion coefficients of K+ ions were predicted by employing the Boltzmann-Matano equation to support the chemical strengthening effect of various alkali and alkaline-earth elements in SAS glasses.

Deep learning–based lesion detection and severity grading of small-bowel Crohn’s disease ulcers on double-balloon endoscopy images

Double-balloon endoscopy (DBE) is widely used in diagnosing small-bowel Crohn's disease (CD). However, CD misdiagnosis frequently occurs if inexperienced endoscopists cannot accurately detect the lesions. The CD evaluation may also be inaccurate owing to the subjectivity of endoscopists. This study aimed to use artificial intelligence (AI) to accurately detect and objectively assess small-bowel CD for more refined disease management. We collected 28,155 small-bowel DBE images from 628 patients from January 2018 to December 2022. Four expert gastroenterologists labeled the images, and at least 2 endoscopists made the final decision with agreement. A state-of-the-art deep learning model, EfficientNet-b5, was trained to detect CD lesions and evaluate CD ulcers. The detection included lesions of ulcer, noninflammatory stenosis, and inflammatory stenosis. Ulcer grading included ulcerated surface, ulcer size, and ulcer depth. A comparison of AI model performance with endoscopists was performed. The EfficientNet-b5 achieved high accuracies of 96.3% (95% confidence interval [CI], 95.7%-96.7%), 95.7% (95% CI, 95.1%-96.2%), and 96.7% (95% CI, 96.2%-97.2%) for the detection of ulcers, noninflammatory stenosis, and inflammatory stenosis, respectively. In ulcer grading, the EfficientNet-b5 exhibited average accuracies of 87.3% (95% CI, 84.6%-89.6%) for grading the ulcerated surface, 87.8% (95% CI, 85.0%-90.2%) for grading the size of ulcers, and 85.2% (95% CI, 83.2%-87.0%) for ulcer depth assessment. The EfficientNet-b5 achieved high accuracy in detecting CD lesions and grading CD ulcers. The AI model can provide expert-level accuracy and objective evaluation of small-bowel CD to optimize the clinical treatment plans.

The effect of ablation settings on lesion characteristics with DiamondTemp ablation system: An exvivo experiment.

Creating large lesion in ablations using the DiamondTemp (DTA) ablation system may reduce the frequency of arrhythmia recurrence and allow the treatment of ventricular arrhythmias. Therefore, this study aimed to investigate whether power, application time, contact force (CF), and contact angle affect lesion formation in the ventricles. Ablations were delivered to porcine myocardial preps to evaluate the lesion characteristics. Ablations were conducted with a maximum power of 50 W, target temperature of 58°C, CF of 10, 20, or 30 g, and contact angle between the catheter tip and tissue. The ablation durations were 15, 30, 60 s, 15 s × 2, or 30 s × 2. Steam pops occurred only in cases with perpendicular contact. The lesion depth was larger in all settings in the perpendicular orientation than in the parallel orientation. The temperatures were lower in all settings in the perpendicular orientation than in the parallel orientation. The lesions became larger as CF increased with perpendicular contact and duration of ≥30 s. The longer application time resulted in larger surface area, depth, and volume of the lesion. Lesion depth was greater with single application of 30 and 60 s than with 15 s × 2 and 30 s × 2, respectively. It is important to perform a single prolonged application as much as possible to create deeper lesions. Parallel contact with the tissue should be maintained to take advantage of the temperature sensor's capabilities to avoid pop phenomenon.

Determination of Sustainable Groundwater Conservation Zones Based on Groundwater Recharge Areas: Case Study: Denpasar City

Groundwater is a valuable resource for meeting the daily needs of humans, which continues to increase along with population growth. Therefore, it is essential to maintain groundwater properly. Groundwater management can be carried out comprehensively in groundwater basins, including determining groundwater recharge areas. This study aims to determine the location of groundwater recharge to conserve groundwater in Denpasar City to create groundwater sustainability. The geospatial analysis uses a weighting and scoring approach (Overlay Weighted Sum) to determine the groundwater recharge area. Retrieval data in the field by observing geological conditions and measuring the depth of the phreatic surface in Denpasar City. The determination of recharge and discharge areas was analyzed using the geospatial method using the ArcGIS 10.8 application using Interpolation Inverse Distance Weighted (IDW). The five parameters used in this scoring assessment are lithology, rainfall, soil cover type, slope, and phreatic surface depth. The highest score obtained from the weighting of the scoring is 46, while the lowest score is 36. The recharge area is found in the weighted value of 41-46, which is in the northern region of Denpasar City. The discharge area is located at a weight value of 36-41 in the southern area of Denpasar City.

Use of Electrical Resistivity Tomography for Joint Geophysical and Geotechnical Landslide Characterization: A Case Study

Abstract Slope movement processes include complex soil and rock failure mechanisms. Their study benefits from a multidisciplinary approach based on a wide range of information including geological and geomorphological mapping, and geotechnical and geophysical investigations. This research paper focuses on the characterization of the Tamentout landslide that occurs in the southeast of Jijel province. The study area belongs to the Tellian domain in which the geological outcrops are dominated by Senonian formations, composed of marl deposits overlain by Numidian flysch of Aquitano-Burdigalian age, with a sloping topography ranging from 20° to 30°. The geophysical approach consists of processing the available geophysical data of resistivity, obtained by the Electrical Resistivity Tomography (ERT). This study aims to characterize the internal structure, and the changes in water saturation within the unstable mass and locate the depth of slip surface associated with this landslide. Through this work, we combined geological and geotechnical investigations with electrical resistivity tomography (ERT). This combination gave a more detailed image of the substrate geology and structure of the landslide zone. The 2D resistivity results show that the basement consists of two main formations. The first one is a highly conductive formation with a resistivity range between 2 and 25 Ωm, a depth of 0-8 m, and is interpreted as a saturated marl-clay overlaying. The second, a hard and compact formation with a resistivity range between 50 and 200 Ωm and a depth range of 8 to 40 m, was interpreted as a substrate of tellian marls. The presence of boulders of Numidian sandstone within the two formations is materialized by a very high resistivity value ranging from 500 to 1000 Ωm. The slip surface was located on the layer with low resistivity (2-25 Ωm). The precise determination of the depth of the shear zone is of vital use in implementing mitigation measures and carrying out the stabilization work of this unstable zone. Through this work, we will highlight the advantage of the combination of available results of the geological, geotechnical investigations and electrical resistivity tomography (ERT) carried out in the study area.

Combined Effects of Fronts, Upwelling and the Biological Pump on Organophosphate Esters in the Changjiang (Yangtze) River Estuary During Summer

AbstractEstuarine and coastal environments are important transport pathways and regional sinks for anthropogenic pollutants. In this study, the occurrence and transport of the continuously released organophosphate esters (OPEs) was investigated together with physical and biochemical parameters throughout the water column in the Changjiang (Yangtze) River estuary during the summer. Total dissolved and particulate OPEs showed great spatial heterogeneity, with mean concentrations of 550 ± 280 ng/L in the estuary, 110 ± 270 ng/L in the front/upwelling zone, and 410 ± 450 ng/L in the continental shelf. OPE concentrations in the estuarine bottom waters were high due to massive terrestrial/sediment inputs. In contrast, the “surface enrichment and depth depletion” of OPEs in the continental shelf was closely related to seasonal stratification. Reduced OPE concentrations were observed in the frontal/upwelling zone due to isopycnal heaving. Frontal activity and upwelling induced phytoplankton blooms in the coastal regions, which jointly contributed to elevated OPEs beneath surface water with high phytoplankton aggregation. The OPEs mainly originated from wastewater treatment plant discharges, industrial pollution and consumer products. These OPEs generally posed a low ecological risk to aquatic lives, but their long‐term effects cannot be ignored due to their continuous high production, usage and release.

Reconciliation of total particulate organic carbon and nitrogen measurements determined using contrasting methods in the North Pacific Ocean as part of the NASA EXPORTS field campaign

Measurements of particulate organic carbon (POC) are critical for understanding the ocean carbon cycle, including biogenic particle formation and removal processes, and for constraining models of carbon cycling at local, regional, and global scales. Despite the importance and ubiquity of POC measurements, discrepancies in methods across platforms and users, necessary to accommodate a multitude of needs and logistical constraints, commonly result in disparate results. Considerations of filter type and pore size, sample volume, collection method, and contamination sources underscore the potential for dissimilar measurements of the same variable assessed using similar and different approaches. During the NASA EXport Processes in the Ocean from RemoTe Sensing (EXPORTS) 2018 field campaign in the North Pacific Ocean, multiple methodologies and sampling approaches for determining POC were applied, including surface inline flow-through systems and depth profiles using Niskin bottles, in situ pumps, and Marine Snow Catchers. A comparison of results from each approach and platform often resulted in significant differences. Supporting measurements, however, provided the means to normalize results across datasets. Using knowledge of contrasting protocols and synchronous or near-synchronous measurements of associated environmental variables, we were able to reconcile dataset differences to account for undersampling of some particle types and sizes, possible sample contamination and blank corrections. These efforts resulted in measurement agreement between initially contrasting datasets and insights on long-acknowledged but rarely resolved discrepancies among contrasting methods for assessing POC concentrations in the ocean.

Current modified higher-order Schrödinger equation of broader bandwidth capillary-gravity waves

A higher-order nonlinear Schrödinger equation of capillary-gravity waves for broader bandwidth on infinite depth of water including the effect of depth uniform current is established. The derivation is made from Zakharov's integral equation by extending the narrow bandwidth restriction to make it more suited for application to problems involving actual sea waves. On the basis of this equation, a stability analysis is made for uniform Stokes waves. After obtaining an instability condition, instability regions in the perturbed wave number space are displayed that are in good agreement with the exact numerical findings. It is found that the modifications in the stability characteristics at the fourth-order term are due to the interaction between the frequency-dispersion term and the mean flow. It is seen that the growth rate of sideband instability decreases due to the effects of both surface tension and depth uniform following currents. Significant deviations of the instability regions are observed between narrow-banded and broader-banded results. In addition, we have depicted the instability growth rate for the case of pure capillary waves.

Comparative analysis of effects of climate-smart agriculture practices and conventional agriculture on selected soil physicochemical properties in Nyimba district, Zambia

Background. Many smallholder farmers in the developing world live in adverse poverty and rely on agriculture as their primary source of income and household food. In Zambia, agriculture production is the main activity for people in rural areas of the country. The study evaluated the effects of climate-smart practices: Gliricidia sepium alley cropping, conservation agriculture basin, ripping, and conventional agriculture cropland on selected physicochemical properties of soil among smallholder farmers’ croplands in Nyimba district, Zambia. Materials and Methods. Cropland under conservation agriculture basin, ripping, agroforestry gliricidia alleyed cropping, and conventional agriculture cropland hosting the practices for more than five years were considered for soil sample collection. Thirty (30) composite soil samples were collected: gliricidia alley cropping (n = 6), conservation agriculture ripping (n = 6), basin (n = 6), conventional agriculture one (n = 6), and conventional agriculture two (n = 6) following a zigzag pattern on soil surface depth of 0–30 cm. The collected composite soil samples were analyzed at the University of Zambia Soil Science Laboratory. Soil laboratory results were analyzed with Minitab Statistical Software version 17 for mean squares, standard deviations, and Tukey’s LSD. Results and Discussion. The study revealed significant effects (p <0.05) of gliricidia alley cropping, conservation agriculture ripping, and basin on soil bulk density, porosity, power of hydrogen (pH), cation exchange capacity, available phosphorus, total nitrogen, exchangeable bases sodium, calcium, and potassium. Exchangeable base magnesium was recorded as insignificant across the considered practices off-course with minimal mean variations with conventional agriculture cropland. Conclusion. The study shows that implementing climate-smart agriculture practices has the potential to improve crop productivity per hectare through reclaiming and amending depleted soil physicochemical properties in a mid and long run. This also indicates the importance of climate-smart agricultural practices implementation among smallholder farmers’ cropping fields.

Interaction of contour geometry and optic flow in determining relative depth of surfaces.

Dynamic occlusion, such as the accretion and deletion of texture near a boundary, is a major factor in determining relative depth of surfaces. However, the shape of the contour bounding the dynamic texture can significantly influence what kind of 3D shape, and what relative depth, are conveyed by the optic flow. This can lead to percepts that are inconsistent with traditional accounts of shape and depth from motion, where accreting/deleting texture can indicate the figural region, and/or 3D rotation can be perceived despite the constant speed of the optic flow. This suggests that the speed profile of the dynamic texture and the shape of its bounding contours combine to determine relative depth in a way that is not explained by existing models. Here, we investigated how traditional structure-from-motion principles and contour geometry interact to determine the relative-depth interpretation of dynamic textures. We manipulated the consistency of the dynamic texture with rotational or translational motion by varying the speed profile of the texture. In Experiment 1, we used a multi-region figure-ground display consisting of regions with dots moving horizontally in opposite directions in adjacent regions. In Experiment 2, we used stimuli including two regions separated by a common border, with dot textures moving horizontally in opposite directions. Both contour geometry (convexity) and the speed profile of the dynamic dot texture influenced relative-depth judgments, but contour geometry was the stronger factor. The results underscore the importance of contour geometry, which most current models disregard, in determining depth from motion.

Optimization of delignification depth of wood surfaces for skin polymer impregnation

We controlled the degree of surface delignification of a wood specimen to impart functionality to its surface and injected a polymer into the porous structure to investigate using it as a functional material. Generally, balsa wood is used in studies aiming to impart functionality through polymer impregnation. However, we used a native Korean tree (Paulownia tomentosa), which has the lowest specific gravity. Peracetic acid (acetic acid and hydrogen peroxide mixture) was used as the delignification solution. Changes in wood surface properties were analyzed according to the delignification treatment duration. Changes in chemical composition, functional groups, cell wall structure, specific gravity, and pores were also observed. Depending on the delignification time, the specific gravity decreased from 0.24 to 0.12. The lignin content was reduced from 29.2% to 0.9%. Fourier Transform Infrared Spectroscopy revealed changes in the lignin functional groups (1 591, 1 507, and 1 240 cm−1), and changes in functional groups derived from hemicellulose (1 720 and 1 182 cm−1). Epoxy infiltration depth was adjusted according to delignification treatment depth to impart wood surface functionality. Our research results indicated that strength and durability could be improved by selectively impregnating polymers into the wood surface requiring functionality, unlike chemically modifying the entire interior of the wood.

Sediment Compaction in Experimental Deltas: Toward a Meso‐Scale Understanding of Coastal Subsidence Patterns

AbstractWe present the first investigation of subsidence due to sediment compaction and consolidation in two laboratory‐scale river delta experiments. Spatial and temporal trends in subsidence rates in the experimental setting may elucidate behavior which cannot be directly observed at sufficiently long timescales, except for in reduced scale models such as the ones studied. We compare subsidence between a control experiment using steady boundary conditions, and an otherwise identical experiment which has been treated with a proxy for highly compressible marsh deposits. Both experiments have non‐negligible compactional subsidence rates across the delta‐top, comparable in magnitude to our boundary condition relative sea level rise rate of 250 μm/hr. Subsidence in the control experiment (on average 54 μm/hr) is concentrated in the lowest elevation (<10 mm above sea level) areas near the coast and is likely related to creep induced by a rising water table near the shoreface. The treatment experiment exhibits larger (on average 126 μm/hr) and more spatially variable subsidence rates controlled mostly by compaction of recent marsh deposits within one channel depth (∼10 mm) of the sediment surface. These rates compare favorably with field and modeling based subsidence measurements both in relative magnitude and location. We find that subsidence “hot spots” may be relatively ephemeral on longer timescales, but average subsidence across the entire delta can be variable even at our shortest measurement window. This suggests that subsidence rates over a short time frame may exceed thresholds for marsh platform drowning, even if the long term trend does not.

Evaluation Heavy Metals Pollution in the Soil from some Regions of Al-Diwaniyah City / Iraq

Soil is the surface layer of the earth’s crust in which plant roots grow and some animals and other microorganisms live in it and it is considered the basis of the ecosystem, so its contamination negatively impact the health of all living organisms, especially humans who are at the top of the food chain. Heavy metals are considered among the most prominent inorganic pollutants in the soil, so this study came to evaluate the concentrations of some toxic heavy metals in areas with different activities in the city of Diwaniyah. The results of the study showed that the concentrations of heavy metals in the surface soil ranged between (0.958-2.292 mg/kg) and (19.132-73.907 mg/kg), (14.882 - 50.012 mg/kg) and (29.689-62.109mg/kg) for cadmium, lead, copper and chromium, respectively, and their concentrations in the soil at depth of 30 cm ranged between (1.529-1.971 mg/kg), (22.160 - 99.885 mg/kg), (12.790-55.630 mg/kg) and (41.278-75.467 mg/kg) for cadmium, lead, copper and chromium, respectively. Soil pollution was evaluated by using some pollution indices such as the geological accumulation index, pollution load index, contamination factor and degree of pollution. The results of pollution indices showed that the surface soil of the surface study sites and depth of 30 cm is contaminated with a very high degree of cadmium. Medium pollution with lead and little pollution with copper and chromium, and this requires great attention in order to reduce soil pollution with heavy metals, especially cadmium and lead.

A comparative Study of the Content of some Microelements in the Soil of the Mouradia Agricultural Project in Babil Governorate

The current study included the selection of three agricultural fields from the soil of the Muradia Agricultural Project of the Directorate of Agriculture in Babil Governorate. Thirty-four samples were taken from them at a surface depth of 0-30 cm, for the purpose of a comparative study of the content of some microelements through soils of various fields with agricultural use. As the size distribution of the soil classes was mostly dominated by silt, and thus the type of tissue ranged from a silty clay mixture to a silty mixture. The soil interaction values ranged between 7.0-7.90, and the electrical conductivity ranged between 1.31-6.23 ds m-1 in all study soils, except for the unexploited comparison soil samples in which the soil interaction values were between 7.36-8.30, and the electrical conductivity ranged between 8.39-24.36. ds m-1. The soil content of organic matter was 10.30-20.00 and 3.40-9.60 g kg-1, respectively. The values of the exchange capacity of the positive ions varied in the soils of the current study, as they ranged between 9.090-14.9 cmol charge kg-1, and its height in other soils ranged between 16.5-25.91 cmol charge kg-1. The values of available iron ranged between 4.12-8.39 mg kg-1 in all the study soils, except for the unexploited comparison soil samples in which it was 4.04-7.63 mg kg-1, while manganese ranged between 5.20-3.55 and 3.16-4.88 mg kg-1, respectively. While copper is between 0.86-2.58 and 0.81-1.99 mg kg-1, respectively, and zinc is 0.87-1.51 and 0.78-1.06 mg kg-1, respectively.

Evaluation of the Readiness of NPK Elements for the Soils of the Mouradia Agricultural Project in Babil Governorate

The current study included the selection of three agricultural fields from the soil of the Muradia Agricultural Project of the Directorate of Agriculture in Babil Governorate. Thirty-four samples were taken from them at a surface depth of 0-30 cm, in order to evaluate the readiness of NPK elements through the soils of various fields with agricultural use. As the size distribution of the soil classes was mostly dominated by silt, and thus the type of tissue ranged from a silty clay mixture to a silty mixture. The soil interaction values ranged between 7.0-7.90, and the electrical conductivity ranged between 1.31-6.23 ds m-1 in all study soils, except for the unexploited comparison soil samples in which the soil interaction values were between 7.36-8.30, and the electrical conductivity ranged between 8.39-24.36 ds m-1. The soil content of organic matter was 10.30-20.00 and 3.40-9.60 mg kg-1, respectively. The values of the exchange capacity of the positive ions varied in the soils of the current study, as they ranged between 9.09-14.9 cmol charge kg-1, and its height in other soils ranged between 16.5-25.91 cmol charge kg-1. The values of available nitrogen ranged between 23.00-48.18 mg kg-1 in all the study soils, except for the unexploited control soil samples in which it was 22.15-30.16 mg kg-1, while phosphorus ranged between -17.54-31.20 and 8.20-17.20 mg kg-1, respectively., while potassium ranged between 175.11-205.16 and 149.30-165.22 mg kg-1, respectively.

Gravity Application to Obtain the Subsurface Structures of Mafid Region, North Nasser Lake, Egypt

This study aims to define structures below the surface of the Mafid Area by using gravity data interpretation. Estimates were made for the contact density contrast and the gravity sources' depths. The source depths and contact locations were estimated using the Euler deconvolution method. Structures with shallow and deep seats were also assessed using power spectrum analysis. The structure at a shallow depth was between 0.032 km and 0.437 km. According to the Euler deconvolution method's outcomes, the basement may be below ground in the area's southernmost portion, and it has grown to between 200 and 300 meters in the area's northernmost portion. Multiple faults affect the region that most trends in the NW-SE, NNW-SSE, E-W, NE-SW, and NNE-SSW directions, according to the structural map that has been interpreted. Three-dimensional gravity modelling shows that the upper surface depth of crystalline rocks (Basement rocks ) ranges from 170 to 374 m.

Fluorine-induced reversible cation/anion redox reactions to enhance stability in Li-rich layered oxides

Low-cost Li-rich layered oxides (LLOs) cathode materials offer excellent initial energy density due to the contribution of cation/anion redox chemistry. However, irreversible redox reactions and phase transitions lead to low initial Coulomb efficiency (ICE) and mediocre cycling stability, which hinders their practical applications. Herein, surface depth fluorine (F)-induced achieved phase transform of Li2MnO3 structure in Li1.2Mn0.64Ni0.16O2 cathodes for the first time, generating a large number of phase-like interfaces and ultrathin interfacial integrated layers, which excite the anion/cation activity and accelerate the redox kinetics. The modified material can inhibit defect generation, increase the Li+ diffusion rate, activate reversible Mn3+/Mn4+ redox reactions, enhance oxygen redox (O2−/On−) activity, and suppress adverse phase transitions. The results show that the ICE of modified electrode is improved to 88.2%, and that the capacity retention is as high as 93.1% and 100% for 200 cycles at 1 C and 2 C. Furthermore, the improved electrochemical performance is also attributed to the formation of strong transition metal-fluorine (TM-F) bonds, which inhibit the TM migration that maintains the intact layered structure during cycling. This strategy provides a new path for efficient surface structure modification of high-energy–density LLOs cathodes.

River-Blocking Risk Analysis of the Bageduzhai Landslide Based on Static–Dynamic Simulation

Landslides blocking rivers in alpine canyon areas can cause great harm. Taking the Bageduzhai landslide on the southeastern margin of the Qinghai-Tibet Plateau as an example, the risk of landslides blocking rivers is analyzed by static analysis and dynamic simulation. Through onsite investigation, it is found that the Bageduzhai landslide is a traction-falling landslide, and there are two sliding surfaces: deep and shallow. Through static analysis of the stability of the Bageduzhai landslide under ordinary rainfall conditions and high-intensity rainfall conditions, the sliding surface position is obtained. On this basis, the smooth particle hydrodynamics method is used to analyze the movement process and accumulation form of the landslide under different working conditions. The analysis results show that the instability volume and sliding surface depth of the landslide under ordinary rainfall conditions are significantly smaller than those under high-intensity rainfall conditions. The instability volume and sliding surface depth under ordinary rainfall conditions can reach 31 m. The river-blocking depth under extreme rainfall conditions can exceed 65 m. The research results provide theoretical support for the risk analysis of the potential river-blocking disaster of the Bageduzhai landslide.

On Human-like Biases in Convolutional Neural Networks for the Perception of Slant from Texture

Depth estimation is fundamental to 3D perception, and humans are known to have biased estimates of depth. This study investigates whether convolutional neural networks (CNNs) can be biased when predicting the sign of curvature and depth of surfaces of textured surfaces under different viewing conditions (field of view) and surface parameters (slant and texture irregularity). This hypothesis is drawn from the idea that texture gradients described by local neighborhoods—a cue identified in human vision literature—are also representable within convolutional neural networks. To this end, we trained both unsupervised and supervised CNN models on the renderings of slanted surfaces with random Polka dot patterns and analyzed their internal latent representations. The results show that the unsupervised models have similar prediction biases as humans across all experiments, while supervised CNN models do not exhibit similar biases. The latent spaces of the unsupervised models can be linearly separated into axes representing field of view and optical slant. For supervised models, this ability varies substantially with model architecture and the kind of supervision (continuous slant vs. sign of slant). Even though this study says nothing of any shared mechanism, these findings suggest that unsupervised CNN models can share similar predictions to the human visual system. Code: github.com/brownvc/Slant-CNN-Biases.