Slope Factor Research Articles

Minimum Safety Factor Evaluation of Slopes Using Hybrid Chaotic Sand Cat and Pattern Search Approach

This study developed an efficient evolutionary hybrid optimization technique based on chaotic sand cat optimization (CSCO) and pattern search (PS) for the evaluation of the minimum safety factor of earth slopes under static and earthquake loading conditions. To improve the sand cat optimization approach’s exploration ability, while also avoiding premature convergence, the chaotic sequence was implemented. The proposed hybrid algorithm (CSCPS) benefits from the effective global search ability of the chaotic sand cat optimization, as well as the powerful local search capability of the pattern search method. The suggested CSCPS algorithm’s efficiency was confirmed by using mathematical test functions, and its findings were compared with standard SCO, as well as some efficient optimization techniques. Then the CSCPS was applied for the calculation of the minimum safety factors of the earth slope exposed to both static and seismic loads, and the objective function was modeled based on the Morgenstern–Price limit equilibrium method, along with the pseudo-static approach. The CSCPS’s efficacy for the evaluation of the minimum safety factor of slopes was investigated by considering two case studies from the literature. The numerical experiments demonstrate that the new algorithm could generate better optimal solutions via calculating lower values of safety factors by up to 10% compared with some other methods in the literature. Furthermore, the results show that, through an increase in the acceleration coefficient to 0.1 and 0.2, the factor of safety decreased by 19% and 32%, respectively.

Development of a land stability index for land damage assessment: the case of a nickel mine, North Konawe, Indonesia

Assessment of land damage has been included in several Indonesian government policies, but it tends to have zero dimensions or only one point in the year. This study tried to propose an inter-time assessment of land damage with a land stability index by including the development of knowledge and technology at nickel mining sites in the easternmost part of North Konawe Regency. Orthophoto and Digital Elevation Model (DEM) images from drones in 2020 were taken in a field survey and used as primary data. While the SPOT 5 Imagery in 2014 and National DEM were collected as secondary data. The developed method combining slope, soil, TRI (Terrain Ruggedness Index), and land cover factor has been considered moderately accurate. Applying the method between different periods has produced a temporal land stability index where a positive value means more unstable, zero means unchanged, and a negative value means more stable. The results showed that after six years, the largest area due to nickel mining in the area has not changed much or had zero value. This is because the area tends to remain a natural forest. The more stable area is located in the southern part of the study site. However, the increasingly unstable area is located in the northern part of the study site. If no reclamation action is taken, the potential for further damage will occur.

Influence of Unsaturated Hydraulic Properties on Transient Seepage and Stability Analysis of an Earthen Dam

Traditionally, the seepage through embankments and other geotechnical structures is estimated using the hydraulic properties of saturated soil. In most cases, the soil is not fully saturated, and the use of saturated soil properties can lead to erroneous results. A reliable assessment of slope stability needs comprehensive characterization of both unsaturated and hydraulic properties of saturated soil. The permeability coefficient of unsaturated soil is usually estimated using existing permeability models derived from the soil water characteristic curve (SWCC) of soil. The performance of these prediction models has not been consistent in the past. A proper determination of unsaturated soil permeability properties will be needed for better stability designs and checks of earth structures. In this study, an experimental program is designed to evaluate the influence of matric suction, net confining stress, and wetting and drying cycles on the hydraulic conductivity of a clayey soil over a wide range of suction values. Modified suction-controlled triaxial equipment was used to apply and maintain suction and hydraulic head in a soil specimen to measure the coefficient of permeability for drying and wetting cycles. Additionally, a series of fully coupled hydromechanic numerical analyses was performed to examine the effect of hydraulic properties of unsaturated soil on pore water pressure response and safety factors of slope for transient seepage conditions during drawdown. The effects of stress-dependent hydraulic properties and hydraulic hysteresis on transient seepage were also investigated. The findings from this study highlight the role of hydraulic properties of partially saturated soil in seepage and slope stability analysis of earthen dams.

Residual Strength Parameter Method for Slope stability on a Toll Road with Expansive Clay

The decreasing stability phenomenon needs to be considered during the design of cut slopes on problematic soil. Excavation slope of toll road construction tends to fail when it lies above clay-shale strata. Certain common correlations and ordinary analytical methods are not recommended for safety calculation. This study is intended to find out the characteristic of clay-shale and proper slope inclination design on Semarang Batang Toll Road. The behaviour of a clay-shale area on the cut slope of Batang-Semarang toll road segment STA 438+000–STA 439+000 was identified. The degradable and expansive properties caused slope failure of the initial design with an inclination of 1 H: 1 V. Laboratory tests found that the soil had a clay faction > 40% and can be categorized as high plasticity (LL > 50%). An empirical approach determined that the residual shear strength decreased to phi < 6 degrees. To describe the swelling after the excavation stage, the flow deformation was determined by a finite element simulation. During the swelling phase, the pore water pressure was maintained at a certain value, and a gentler slope fulfilled the minimum safety factor with an inclination of 1 V: 3 H. Furthermore, the shear strength of the clay-shale was reduced to that for a fully softened material, and all the slope factors for safety moved to a critical state. According to the simulation, the minimum suggested slope inclination is 5 H: 1 V. This approach is important for the maintenance of pore water pressure and the prevention of an additional reduction in the shear strength so as to avoid slope failure on clay-shale regions in the yielding stage.

Stability Assessment of Multi-Stage Slopes Considering Local Failure

The analytical method for slope stability analysis requires a collapse mechanism in advance. The collapse mechanism for a multi-staged slope is generally assumed to be overall failure, whereas this kind of slope may suffer from local failure. However, a local failure is rarely reported in the previous research for multi-staged slopes, which may result in an overestimate for slope stability. To this end, local failure is incorporated into the collapse mechanism for the first time, so as to develop a complete approach to assess the stability of multi-stage slopes. The modified pseudo-dynamic method is conducted to properly account for seismic effects. Thanks to the limit analysis method and strength reduction technique, the safety factor of a multi-stage slope is obtained. The result obtained by the presented approach shows a good agreement with that of previous literature and numerical calculations. The collapse mechanism of multi-stage slopes is studied, and the safety factor is presented schematically for a wide range of parameters. The results show that the local failure for a multi-stage slope often manifests under the intense seismic effects.

Effect of Chlorophyll in Garlic Chives (Allium tuberosum) Leaves by Drought and pH

Allium tuberosum Rotter (garlic chives) is a species of plant native to the Chinese province and naturalized elsewhere in Asia and around the world. In Korea, chives are boiled and used as seasoned vegetables or as soup ingredients, and are also used for chive kimchi and cucumber pickles. This paper describes experimental results for chlorophyll content and efficiency with drought stress and soil acidity on garlic chives. Analytical determination of total chlorophyll (a, b) was performed with spectrophotometer. Chlorophyll fluorescence analysis was used to measure photosynthetic parameters with the Imaging-PAM Chlorophyll Fluorometer. The content of total chlorophyll was 0.711 at 80% moisture. The content for chlorophylls a, b, and total were 0.333, 0.151, and 0.390 at 10% moisture, respectively. The simple type of regression showed the relation between chlorophylls as a function of acidity. The slope factors for chlorophyll content (a, b, and total) were 0.866, 0.903, and 0.910, respectively. The current fluorescence yield (Ft) was increased to the decrease of water in soils. The maximal PSII quantum yield, Fv/Fm was the highest at 70% moisture among nine moisture percentage stages. The slope factors of Ft, Fm (maximum fluorescence yield), Fv (quenched state), and Fv/Fm for chlorophyll efficient indicators were -0.873, 0.977, 969, and 0.897, respectively. Water stress decreased chlorophyll a, chl b, chl (a + b) contents, and the chl a/b ratio in the A. tuberosum. Low soil pH also affected the chlorophyll content and efficiency of A. tuberosum.

IN-SITU REMEDIATION OF HEAVY METAL CONTAMINATED SITES THROUGH MECHANICAL STABILIZATION USING INDUSTRIAL WASTE PRODUCTS

The present study aimed to assess the stabilization performance of fly ash, blast furnace slag and quick lime for heavy metals in contaminated soil at a landfill site at Kolkata, West Bengal, India. The physical properties and strength parameters of the contaminated soil substantially increased after additives application. Moreover, the heavy metal concentrations in the leachate of the polluted soil were found almost nil after optimum blending of the additives mechanically with the soil and post-curing for 7 days. The numerical modeling studies were also carried out using PLAXISTM 3D software to ascertain the improvement of safety factor and deformation caused at the foundation level of an embankment constructed on such stabilized soil. The vertical displacement of the embankment founded on stabilized soil reduced from 194.3 to 136.3 mm and the safety factor of the embankment slope (1 V:1.5 H) increased from 2.5 to 3.2 under drained condition.

Development of a Comprehensive Approach to Assessing the Content of Elemental Contaminants in Native Herbal Medicinal Products, Using Pumpkin Seeds as a Case Study

Native herbal medicinal products (NHMPs) are medicinal products derived from plant raw materials. NHMPs are characterised by a complete transfer of contaminants from raw materials to finished products and comparability of therapeutic doses to daily consumption of many foods. The aim of the study was to develop an approach to assessing the content of elemental contaminants in NHMPs, based on public health risk assessment methods, and exemplify its use by applying it to pumpkin seeds. Materials and methods : the study analysed national and international regulatory documents governing the control of elemental contaminants in medicinal products and food, as well as literature on the ability of pumpkin seeds to accumulate such contaminants. In order to determine permitted concentrations, hazard quotients and cancer slope factors, the authors used internationally accepted risk assessment criteria. Results : the study identified the elemental contaminants to be controlled during risk assessment of NHMPs (i.e., As, Cd, Co, Cr, Pb, Hg, Ni, and V). The authors calculated permitted concentrations of the elements for a therapeutic dose of pumpkin seeds; hazard quotients for the essential (Co, Cr, Cu, Fe, Mn, Mo, Se, Zn), probably essential (As, Ni, V) and toxic (Al, Cd, Hg, Pb, Sr, Tl) elements consumed with the dose; and individual cancer risks associated with As, Cd, Cr, Pb. Conclusions : the total health impact of the studied elements in a therapeutic dose of pumpkin seeds is permissible, and there is no risk of non-carcinogenic effects. The content of each carcinogenic element in pumpkin seeds corresponds to the acceptable level of maximum individual cancer risk. These risk levels are to be controlled at all times. The results of this study may support the development of a compendial monograph on pumpkin seeds.

Assessment of the inhalation exposure and incremental lifetime cancer risk of PM2.5 bounded polycyclic aromatic hydrocarbons (PAHs) by different toxic equivalent factors and occupancy probability, in the case of Xi'an.

Polycyclic aromatic hydrocarbons (PAHs) are widespread toxic pollutants in the atmosphere and have attracted much attention for decades. In this study, we compared the health risks of PAHs based on different toxic equivalent factors (TEFs) in a heavily polluted area during heating and non-heating periods. We also pay attention to occupancy probability (OP) in different polluted areas. The results showed that there were big differences for calculations by different TEFs, and also by OP or not. Age groups except adults were all lower calculated by OP than not. The sensitivity analysis results on the incremental lifetime cancer risks (ILCR) for population groups by Monte Carlo simulation identified that the cancer slope factor extremely affected the health risk assessment in heating periods, followed by daily inhalation exposure levels. However, daily inhalation exposure levels have dominated the effect on the inhalation ILCR and then followed by the cancer slope factor in non-heating periods. The big differences by different calculations investigated that it is important to set up the correlations between the pollution level and health risks, especially for the longtime health assessment.

PREDIKSI LAJU EROSI PADA DAERAH TANGKAPAN AIR BENDUNGAN DENGAN METODE USLE (STUDI KASUS : BENDUNGAN TITAB)

Erosion is a serious problem in watershed management. The Saba watershed is a water catchment area at the Titab Dam in Buleleng Regency, Bali Province. The existence of the Titab Dam is accompanied by the development of activities of the surrounding community, both tourism, economic and daily activities. Unfortunately, this activity in the future will have a negative impact on the condition of the dam so that it poses a risk. This study aims to determine the amount of sediment inflow with land erosion approach at the Titab Dam using the USLE (Universal Soil Loss Equation) method. Erosion rate prediction was carried out using the USLE method and with the help of ArcGIS 10.8 software. From the results of the analysis, it was found that in the Titab Dam catchment area, only 3 classes were obtained. The results of the calculation of the erosion rate using the USLE method showed that the magnitude of the erosion was 439,962 tons/year or 53.05 tons/ha/year. In addition, the most influential factors on the rate of erosion are the length and slope factors. In addition, land cover is also one of the most influential factors.

The codevelopment of reading and attention from middle childhood to early adolescence: A multivariate latent growth curve study.

Attention skills are strong cross-sectional predictors of reading comprehension from childhood through to adolescence. However, less is known about the developmental relations between these two domains across this period. This study examined the codevelopment of reading and attention in a community sample of 614 Australian school students (50% female). Reading and attention were assessed at ages 8, 10, 12, and 14. Results of univariate latent growth models demonstrated, on average, curvilinear trajectories for reading in which rapid growth across younger age spans decelerates as children reach adolescence. By contrast, attention skills remained relatively stable on average. Significant negative correlations were observed between the intercept and slope factors in separate reading (r = -.62) and attention models (r = -.39) suggesting compensatory growth patterns in which poorer performing students in both domains at age 8 have steeper trajectories than their higher performing peers. A comparison of a multivariate latent growth model and an autoregressive latent trajectory model with structured residuals (ALT-SR) examined the interrelatedness of development in reading and attention. Both between-individual and within-individual cross-domain parameters showed reading and attention to be positively related at Grade 3, indicating an association between better attention and higher reading achievement at age 8. However, there was little evidence for interrelated growth across domains in this sample. The results contribute to theories which explain whether and how multiple cognitive domains codevelop over a substantial period of childhood and early adolescence. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

A Study on the Influence of Vegetation Growth on Slope Stability

Vegetation plays a major role in terms of slope stability. Roots of grass and trees can increase the strength properties of soil which improves the stability of slope. A natural slope consists of grass and infinite number of trees inclined in different directions along with inclined roots. The aim of the paper is to study the effects of vegetation growth on slope stability for different root reinforced soil depth by varying tree inclination (along with roots), root spread and tree spacing for different slope geometry. The study involves determination of safety factor (FOS) of natural slope existing with and without vegetation growth (such as only grass, grass and trees). GeoStudio Slope/w software with limit equilibrium method was used for stability analysis of different slope inclinations. A tree was modelled as a point load and its roots were represented as reinforced soil properties with anchors and only as root reinforced soil. When compared to the bare slope, it was observed that there was an increase in FOS of slope on both the models of vegetation. Variations in FOS by varying root reinforced soil depth, tree inclinations and spacings were reported for different slope geometry and compared. Considering all these parameters, an empirical corelation for computation of vegetation influenced FOS has been developed. This study provides a mechanical accountability of vegetation cover on the stability of slopes.

Combination of Hyperspectral and Machine Learning to Invert Soil Electrical Conductivity

An accurate estimation of soil electrical conductivity (EC) using hyperspectral techniques is of great significance for understanding the spatial distribution of solutes and soil salinization. Although spectral transformation has been widely used in data pre-processing, the performance of different pre-processing techniques (or combination methods) on different models of the same data set is still ambiguous. Moreover, extremely randomized trees (ERT) and light gradient boosting machine (LightGBM) models are new learning algorithms with good generalization performance (soil moisture and above-ground biomass), but are less studied in estimating soil salinity in the visible and near-infrared spectra. In this study, 130 soil EC data, soil measured hyperspectral data, topographic factors, conventional salinity indices such as Salinity Index 1, and two-band (2D) salinity indices such as ratio indices, were introduced. The five spectral pre-processing methods of standard normal variate (SNV), standard normal variate and detrend (SNV-DT), inverse (1/OR) (OR is original spectrum), inverse-log (Log(1/OR) and fractional order derivative (FOD) (range 0–2, with intervals of 0.25) were performed. A gradient boosting machine (GBM) was used to select sensitive spectral parameters. Models (extreme gradient boosting (XGBoost), LightGBM, random forest (RF), ERT, classification and regression tree (CART), and ridge regression (RR)) were used for inversion soil EC and model validation. The results reveal that the two-dimensional correlation coefficient highlighted EC more effectively than the one-dimensional. Under SNV and the second order derivative, the two-dimensional correlation coefficient increased by 0.286 and 0.258 compared to the one-dimension, respectively. The 13 characteristic factors of slope, NDI, SI-T, RI, profile curvature, DOA, plane curvature, SI (conventional), elevation, Int2, aspect, S1 and TWI provided 90% of the cumulative importance for EC using GBM. Among the six machine models, the ERT model performed the best for simulation (R2 = 0.98) and validation (R2 = 0.96). The ERT model showed the best performance among the EC estimation models from the reference data. The kriging map based on the ERT simulation showed a close relationship with the measured data. Our study selected the effective pre-processing methods (SNV and the 2 order derivative) using one- and two-dimensional correlation, 13 important factors and the ERT model for EC hyperspectral inversion. This provides a theoretical support for the quantitative monitoring of soil salinization on a larger scale using remote sensing techniques.

Characterization, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in urban soils from 23 cities in China.

Concentrations, composition profiles, sources, and health risks of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in urban soils from 23 cities across China based on metadata collected from previous studies between 2005 and 2021 were investigated. ΣPAH concentrations in urban soils from 23 cities across China ranged from 0.1231 to 17.2000mg/kg (mean = 2.7171 ± 3.8276mg/kg). Overall PAH contamination in urban soils across China was moderate compared to that in global cities. Based on energy consumption and climate conditions, the spatial distributions of mean ΣPAH concentrations in Northeast China were highest, followed by those in North China, West China, East China, and South China. Individual PAH composition profiles decreased in the order: 4-ring PAHs (41.36%) > 5-ring PAHs (21.77%) > 3-ring PAHs (18.53%) > 6-ring PAHs (14.00%) > 2-ring PAHs (2.27%). Diagnostic ratios and positive matrix factorization (PMF) revealed that PAHs in urban soils were mainly derived from fossil fuel combustion (from coal, natural gas, and biomass), especially in North, Northeast, and East China, with smaller contributions from petrogenic sources. Health risk assessment results suggest that although there are potential cancer risks from PAHs, risks were acceptable. Toxic equivalent concentration (TEQ) and the corresponding oral cancer slope factor (CFS0) contributed most to the uncertainty of total risks. This study will help develop strategies to reduce PAH risk management in urban soils in China.

Mathematics Students’ Characteristics of Basic Mental Models of the Derivative

The concept of derivative is characterised with reference to four basic mental models. These are described as theoretical constructs based on theoretical considerations. The four basic mental models—local rate of change, tangent slope, local linearity and amplification factor—are not only quantified empirically but are also validated. To this end, a test instrument for measuring students’ characteristics of basic mental models is presented and analysed regarding quality criteria.Mathematics students (n = 266) were tested with this instrument. The test results show that the four basic mental models of the derivative can be reconstructed among the students with different characteristics. The tangent slope has the highest agreement values across all tasks. The agreement on explanations based on the basic mental model of rate of change is not as strongly established among students as one would expect due to framework settings in the school system by means of curricula and educational standards. The basic mental model of local linearity plays a rather subordinate role. The amplification factor achieves the lowest agreement values. In addition, cluster analysis was conducted to identify different subgroups of the student population. Moreover, the test results can be attributed to characteristics of the task types as well as to the students’ previous experiences from mathematics classes by means of qualitative interpretation. These and other results of students’ basic mental models of the derivative are presented and discussed in detail.

Study on Stability Analysis of Soil-Rock-Mixture Slopes under Freeze-Thaw Erosion in Greater Khingan Mountains

Abstract Under the action of freeze-thaw erosion, slopes in permafrost regions frequently suffer from geological disasters. The unique properties of soil-rock-mixture slopes further complicate this freeze-thaw stability problem. To study the effects of freeze-thaw erosion on the stability of soil-rock-mixture slopes, several indoor tests were first carried out on the specimens collected from the target bare slope at the K105+750~K105+850 section of the Ali River to the Kubuchun Forest Farm along National Highway 332 in permafrost regions of Greater Khingan Mountains, and then, according to the test results, damage theory, strength reduction method, Python script, and ABAQUS numerical analysis software, the slippage and safety factor of the bare slope under freeze-thaw cycles were obtained, and finally, the damage degree of freeze-thaw erosion to the bare slope was quantified. To improve the stability of bare slope in the freeze-thaw environment, the composite ecological slope protection measures of arched skeleton + three-dimensional net + grass planting were finally selected, and its feasibility is verified with the help of on-site monitoring and numerical simulation; then, the long-term freeze-thaw stability of the slope after revetment was studied. Key findings indicated that (1) the threshold between soil and rock in the target slope was 5 mm, the soil-to-rock mass and volume ratios of the slope were 55.04% : 44.96% and 69.38% : 30.62%, respectively. (2) After the 150 freeze-thaw cycles, the peak strength and elastic modulus of the specimens decreased 59.7% and 79.50%, respectively. (3) Meanwhile, the freeze-thaw damage was 0.79. (4) The slope safety factor was inversely proportional to the number of freeze-thaw cycles. The target bare slope was unstable after 150 freeze-thaw cycles, and the safety stability reduction rate was 41%. (5) Compared with the bare slope, the shallow horizontal slip of the slope after revetment decreased from 1.528 m to 4.971 cm, and the slope safety factor increased from 0.997 to 4.501, which shows that the slope protection measures are initially feasible. In addition, the numerical analysis results are consistent with the field monitoring data, and the error between the two is ≤2.01%, which proves the rationality of the numerical model established in this paper and provides data support for subsequent research.

Soil erosion spatio-temporal exploration and Geodetection of driving factors using InVEST-sediment delivery ratio and Geodetector models in Dongsheng, China

Assessment of soil erosion processes and accurately identifying erosion drivers is crucial for effective control and conservation strategies. We introduced a new approach involving the integration of the SDR of the InVEST and Geodetector models to explore the spatio-temporal variability of erosion and investigate the key drivers contributing to soil erosion. The results revealed an average soil loss increase of 19 to 37 t ha−1 yr−1 in the watershed from 1990 to 2020, respectively. Cropland areas had the highest growth in soil loss from 26.53 in 1990 to 118.76 t ha−1 yr−1 in 2020. The Geodetector revealed that the key variables influencing erosion are vegetation, slope, precipitation, and aspect factors. The interaction of slope and aspect, slope and precipitation, had the strongest influence on erosion than other variables, with q values of 0.80 and 0.79, respectively. The approach of this study can be used in other regions characterized by severe soil erosion.

Aging Stability Analysis of Slope Considering Cumulative Effect of Freeze–Thaw Damage—A Case Study

The change of physical and mechanical properties of slope rock mass in open-pit mines in seasonally frozen area under the action of freeze–thaw cycles is one of the main reasons for slope instability. In this paper, taking the mechanical parameters of coal seam and sandstone layer in the Beitashan Pasture Open-Pit Mine in Xinjiang as the research object, considering the combined effect of the frost-heave tensile stress in the crack perpendicular to the crack surface and the three-dimensional confining pressure in the crack, the criterion for cracking of fractured rock mass under freeze-thaw condition is determined by applying the principle of stress superposition and the theory of strain energy density factor, and the theoretical frost-heave stress required for cracking is deduced. On this basis, the sensitivity analysis of the fixed factors and variable factors to the theoretical frost-heave stress was performed, respectively. Finite element analysis was utilized to analyze the slope stability under the attenuation of five groups of different rock mass mechanical properties and to determine the slope angle required for the slope stability. Seven different slope angles of sidewall mining ranging from 36° to 51° are analyzed. The results of finite element analysis show that considering the timeliness difference of rock mass parameters with time, the safety factor of slope is reduced from the original 1.70 to 1.18, and 91,500 tons of coal resources can be recovered every year, with remarkable economic benefits.

FC025: Physiological Role of KV Channel in Ureter Smooth Muscle Cell Investigated Quantitatively by Electrophysiological Modeling

Abstract BACKGROUND AND AIMS Spontaneous peristaltic contraction disorder of the ureter smooth muscle (USM) is an important etiology of congenital giant ureter, congenital ureteropelvic junction deformity and non-obstructive hydronephrosis [1]. The USM cell action potential (AP) plays a key role in commencing USM contraction by allowing influx of Ca2+ from the extra cellular space [2]. Therefore, an in-depth quantitative investigation of the USM cell AP generation will assist in developing better pharmacological therapies for the USM abnormal contraction. The purpose of this in-silico study is to unfold the physiological role of Kv channel in modulating the USM AP generation. METHOD The model consists voltage- dependent Na+ currents (INa), hyperpolarization-activated cyclic nucleotide- gated current (Ih), voltage- dependent Ca2+ currents (ICa), Ca2+ dependent potassium channel (IBKCa) and voltage-dependent potassium channels (IKv) as the components of active electrophysiological characteristics [3]. All ion channels are represented by the Hodgkin–Huxley formalism. The maximum conductance of the is varied to investigate the physiological role of the Kv channel in modulating the USM AP generation. RESULTS The whole cell IKv current is generated by applying the voltage clamp protocol, where the membrane potential is stepped from a holding potential of –80 mV–60 mV for a duration of 500 ms. The half activation potential, half inactivation potential, activation slope factor and inactivation slope factors are: 43 mV, –76.1 mV, 15.4 mV and 6.5 mV, respectively, to fit the Boltzmann function equation. The model reveals that fast activation and inactivation properties are the essential feature of IKv for the USM cell. The resting membrane potential (RMP) is set at –50 mV. The AP was induced in the whole cell model by applying an external stimulus current (10–30 pA), as a brief square pulse of 500 ms duration. It is demonstrated that IKv opposes the Ca2+ current during the first 50 ms of the AP duration and then inactivated. It doesn't contribute to the repolarizing phase of the AP. CONCLUSION The plateau phase of the USM AP shows that the total AP duration much longer than that in other smooth muscle cells. It strongly supports the phenomenon is due to the activation of Ca2+-dependent K+ channel and inactivation of L-type Ca2+ channel. In ureter cells, the IKv does not contribute significantly to the repolarization of the AP, but it may regulate membrane excitability by opposing Ca2+ current activated around the threshold of the AP. Therefore, the agonist and antagonist of the IKv might be useful partially as new pharmacological targets for the USM abnormal contraction.

THE ANALYSIS LANDSLIDES POTENTIAL DUE TO CHANGES OF LAND-USE IN MIU WATERSHED

This study aims to determine the magnitude of land-use change in the Miu watershed and to determine the relation between slope and soil type to erosions. The method used to predict the rate of erosion is the Universal Soil Loss Equation (USLE) in 2005, 2010, and 2016 with the help of the Geographic Information System (GIS). This study uses data on rainfall, slope, soil type, land use, and conservation and crop management factors which are then entered into the USLE equation. From this equation, the actual erosion rate in 2005 was 2,634,104.25 tons / year, 2010 was 3,285,025.34 tons / year, and 2016 was 1,856,140.79 tons / year. The average actual erosion in 2005, 2010, and 2016 was 2,591,756.79 tons/year, which is classified as minor erosion. The landslide-prone area based on the lowest slope of 5.50% is equivalent to an area of ​​36 km2, for the medium it is 34.81% equivalent to an area of ​​228 km2, and a height of 59.69% covering an area of ​​391 km2 where very steep slopes dominate this river basin. The effect of significant land-use change affects the rate of erosion when there is a high intensity of rain on a steep slope so the potential for erosions in the area.