scholarly journals Geomorphic diversity and landslide susceptibility in the Balason River Basin, Darjeeling Himalaya

2020 ◽  
Vol 27 (1) ◽  
pp. 13-24
Author(s):  
Subrata Mondal ◽  
Sujit Mandal
Keyword(s):  
Landslide Susceptibility ◽  
Slope Failure ◽  
Principal Component ◽  
Drainage Density ◽  
Slope Instability ◽  
Operating Characteristics ◽  
Hypsometric Integral ◽  
Data Layer ◽  
Data Layers

This study attempts to assess the role of basin morphometric parameters in slope instability using a morphometric diversity (MD) model, as well as the role of drainage parameters and relief parameters in slope failure using drainage diversity (DD) and relief diversity (RD) models, respectively. For this, a total of 14 morphometric data layers were considered. The relationship of each data layer to landslide susceptibility was judged using a frequency ratio (FR) approach. Parameters like drainage density (Dd), drainage frequency (Df), relative relief (Rr), drainage texture (Dt), junction frequency (Jf), infiltration number (In), ruggedness index (Ri), dissection index (Di), elevation (E), slope (S), relief ratio (Rra) and hypsometric integral (Hi) were positively related with landslide potentiality while bifurcation ratio (Rb) and drainage intensity (Din) negatively correlated with S failure. The principal component analysis (PCA)-based weight assigned to each data layer in each model was multiplied with unidirectional reclassified data layers for each model using a weighted linear combination (WLC) approach to prepare landslide susceptibility maps. The receiver operating characteristics curve showed that the landslide prediction accuracy of the DD, RD and MD models were 71.4%, 73.9% and 76.3%, respectively. The FR plots of the aforesaid three models suggested that the chance of landslide increases from very low to very high in susceptible zones.

scholarly journals LANDSLIDE SUSCEPTIBILITY MAPPING BY GIS-BASED QUALITATIVE WEIGHTING PROCEDURE IN CORINTH AREA

2018 ◽  
Vol 36 (2) ◽  
pp. 904 ◽  
Author(s):  
M. Foumelis ◽  
E. Lekkas ◽  
I. Parcharidis
Keyword(s):  
Landslide Susceptibility ◽  
Rapid Assessment ◽  
Time Frame ◽  
Susceptibility Mapping ◽  
Slope Instability ◽  
Landslide Susceptibility Mapping ◽  
Susceptibility Map ◽  
Potential Index ◽  
Degree Of Stability ◽  
Data Layers

Landslide susceptibility mapping refers to a division of the land into zones of varying degree of stability based on an estimated significance of causative factors in inducing the instability. Maps of landslide susceptibility (relative hazard) are usually prepared on regional scales from 1:25.000 - 1:50.000. An advantage of regional studies is that they allow rapid assessment and hence larger areas can be covered in short durations. Factors (data layers) used for the preparation of the landslide susceptibility map were obtained from different sources such as topographic maps, geological maps and satellite images. All the above data layers were converted to raster format in the GIS, each representing an independent variable of a constructed spatial database. Computerization of the database would be necessary to make such analysis possible within an acceptable time frame. According to their relative importance to slope instability in the study area, the various classes of different data layers were assigned weights between 0,0 and 1,0 (collectively adding to 1,0). The overall susceptibility was calculated as an index named SPI (Susceptibility Potential Index), expressing the combination of the different weighted layers into a single map using a certain combination rule. Reclassification of susceptibility scores, based on natural breaks in the cumulative frequency histogram of SPI values, were used to delineate various susceptibility zones namely, very high, high, moderate, low and very low. Verification of results by overlaying susceptibility map and landslide inventory data and adjustment of zone's boundaries was the last stage of the study, allowing the reconsideration in some cases of the weights given

Quantitative Hazard Analysis for Landslides in Hulu Kelang area, Malaysia

2015 ◽  
Vol 73 (1) ◽  
Author(s):  
Nader Saadatkhah ◽  
Azman Kassim ◽  
Lee Min Lee ◽  
Gambo Haruna Yunusa
Keyword(s):  
Landslide Susceptibility ◽  
Frequency Ratio ◽  
Hazard Analysis ◽  
Drainage Density ◽  
Weighting Factor ◽  
Slope Aspect ◽  
Susceptibility Map ◽  
Operating Characteristics ◽  
Stream Power ◽  
Topographic Wetness Index

Hulu Kelang is a region in Malaysia which is very susceptible to landslides. From 1990 to 2011, a total of 28 major landslide events had been reported in this area. This paper evaluates and compares the probability-frequency ratio (FR), statistical index (Wi), and weighting factor (Wf), used for assessing landslide susceptibility in the study area. Eleven landslide influencing factors were considered in the analyses. These factors included lithology, land cover, curvature, slope inclination, slope aspect, drainage density, elevation, distance to lake and stream, distance to road and trenches and two indices (the stream power index (SPI) and the topographic wetness index (TWI)) found in the area. The accuracy of the maps produced from the three models was verified using a receiver operating characteristics (ROC). The verification results indicated that the probability-frequency ratio (FR) model which was developed quantitatively based on probabilistic analysis of spatial distribution of historical landslide events was capable of producing a more reliable landslide susceptibility map in this study area compared to its other counterparts. About 89% of the landslide locations have been predicted accurately by using the FR map. 

scholarly journals Distribution and Severity of Placental Lesions Caused by the Chlamydia abortus 1B Vaccine Strain in Vaccinated Ewes

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 543
Author(s):  
Sergio Gastón Caspe ◽  
Javier Palarea-Albaladejo ◽  
Clare Underwood ◽  
Morag Livingstone ◽  
Sean Ranjan Wattegedera ◽  
...  
Keyword(s):  
Disease Outbreaks ◽  
Principal Component ◽  
Placental Pathology ◽  
Wild Type ◽  
Cell Infiltrate ◽  
Chlamydia Abortus ◽  
Vaccine Type ◽  
The Difference ◽  
Enzootic Abortion Of Ewes

Chlamydia abortus infects livestock species worldwide and is the cause of enzootic abortion of ewes (EAE). In Europe, control of the disease is achieved using a live vaccine based on C. abortus 1B strain. Although the vaccine has been useful for controlling disease outbreaks, abortion events due to the vaccine have been reported. Recently, placental pathology resulting from a vaccine type strain (vt) infection has been reported and shown to be similar to that resulting from a natural wild-type (wt) infection. The aim of this study was to extend these observations by comparing the distribution and severity of the lesions, the composition of the predominating cell infiltrate, the amount of bacteria present and the role of the blood supply in infection. A novel system for grading the histological and pathological features present was developed and the resulting multi-parameter data were statistically transformed for exploration and visualisation through a tailored principal component analysis (PCA) to evaluate the difference between them. The analysis provided no evidence of meaningful differences between vt and wt strains in terms of the measured pathological parameters. The study also contributes a novel methodology for analysing the progression of infection in the placenta for other abortifacient pathogens.

scholarly journals From scenario-based seismic hazard to scenario-based landslide hazard: rewinding to the past via statistical simulations

2021 ◽  
Author(s):  
Luguang Luo ◽  
Luigi Lombardo ◽  
Cees van Westen ◽  
Xiangjun Pei ◽  
Runqiu Huang
Keyword(s):  
Ground Motion ◽  
Land Use Planning ◽  
Landslide Susceptibility ◽  
Additive Model ◽  
Slope Instability ◽  
Susceptibility Map ◽  
Jiuzhaigou Earthquake ◽  
Full Spectrum ◽  
The Past ◽  
Time Invariant

AbstractThe vast majority of statistically-based landslide susceptibility studies assumes the slope instability process to be time-invariant under the definition that “the past and present are keys to the future”. This assumption may generally be valid. However, the trigger, be it a rainfall or an earthquake event, clearly varies over time. And yet, the temporal component of the trigger is rarely included in landslide susceptibility studies and only confined to hazard assessment. In this work, we investigate a population of landslides triggered in response to the 2017 Jiuzhaigou earthquake ($$M_w = 6.5$$ M w = 6.5 ) including the associated ground motion in the analyses, these being carried out at the Slope Unit (SU) level. We do this by implementing a Bayesian version of a Generalized Additive Model and assuming that the slope instability across the SUs in the study area behaves according to a Bernoulli probability distribution. This procedure would generally produce a susceptibility map reflecting the spatial pattern of the specific trigger and therefore of limited use for land use planning. However, we implement this first analytical step to reliably estimate the ground motion effect, and its distribution, on unstable SUs. We then assume the effect of the ground motion to be time-invariant, enabling statistical simulations for any ground motion scenario that occurred in the area from 1933 to 2017. As a result, we obtain the full spectrum of potential coseismic susceptibility patterns over the last century and compress this information into a hazard model/map representative of all the possible ground motion patterns since 1933. This backward statistical simulations can also be further exploited in the opposite direction where, by accounting for scenario-based ground motion, one can also use it in a forward direction to estimate future unstable slopes.

scholarly journals The lung microbiota in Korean patients with non-tuberculous mycobacterial pulmonary disease

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sung-Yoon Kang ◽  
Hyojung Kim ◽  
Sungwon Jung ◽  
Sang Min Lee ◽  
Sang Pyo Lee
Keyword(s):  
Principal Component Analysis ◽  
Respiratory Tract ◽  
Pulmonary Disease ◽  
Beta Diversity ◽  
Lower Respiratory Tract ◽  
Principal Component ◽  
Control Group ◽  
Flexible Bronchoscope ◽  
Bronchial Washing

Abstract Background The microbiota of the lower respiratory tract in patients with non-tuberculous mycobacterial pulmonary disease (NTM-PD) has not been fully evaluated. We explored the role of the lung microbiota in NTM-PD by analyzing protected specimen brushing (PSB) and bronchial washing samples from patients with NTM-PD obtained using a flexible bronchoscope. Results Bronchial washing and PSB samples from the NTM-PD group tended to have fewer OTUs and lower Chao1 richness values compared with those from the control group. In both bronchial washing and PSB samples, beta diversity was significantly lower in the NTM-PD group than in the control group (P = 2.25E-6 and P = 4.13E-4, respectively). Principal component analysis showed that the PSBs and bronchial washings exhibited similar patterns within each group but differed between the two groups. The volcano plots indicated differences in several phyla and genera between the two groups. Conclusions The lower respiratory tract of patients with NTM-PD has a unique microbiota distribution that is low in richness/diversity.

scholarly journals Formation Patterns of Mediterranean High-Mountain Water-Bodies in Sierra-Nevada, SE Spain

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 438
Author(s):  
Jose Luis Diaz-Hernandez ◽  
Antonio Jose Herrera-Martinez
Keyword(s):  
Sierra Nevada ◽  
Unknown Origin ◽  
Slope Instability ◽  
Water Bodies ◽  
High Mountain ◽  
Mountain Areas ◽  
Glacial Processes ◽  
The Mediterranean ◽  
Water Volumes

At present, there is a lack of detailed understanding on how the factors converging on water variables from mountain areas modify the quantity and quality of their watercourses, which are features determining these areas’ hydrological contribution to downstream regions. In order to remedy this situation to some extent, we studied the water-bodies of the western sector of the Sierra Nevada massif (Spain). Since thaw is a necessary but not sufficient contributor to the formation of these fragile water-bodies, we carried out field visits to identify their number, size and spatial distribution as well as their different modelling processes. The best-defined water-bodies were the result of glacial processes, such as overdeepening and moraine dams. These water-bodies are the highest in the massif (2918 m mean altitude), the largest and the deepest, making up 72% of the total. Another group is formed by hillside instability phenomena, which are very dynamic and are related to a variety of processes. The resulting water-bodies are irregular and located at lower altitudes (2842 m mean altitude), representing 25% of the total. The third group is the smallest (3%), with one subgroup formed by anthropic causes and another formed from unknown origin. It has recently been found that the Mediterranean and Atlantic watersheds of this massif are somewhat paradoxical in behaviour, since, despite its higher xericity, the Mediterranean watershed generally has higher water contents than the Atlantic. The overall cause of these discrepancies between watersheds is not connected to their formation processes. However, we found that the classification of water volumes by the manners of formation of their water-bodies is not coherent with the associated green fringes because of the anomalous behaviour of the water-bodies formed by moraine dams. This discrepancy is largely due to the passive role of the water retained in this type of water-body as it depends on the characteristics of its hollows. The water-bodies of Sierra Nevada close to the peak line (2918 m mean altitude) are therefore highly dependent on the glacial processes that created the hollows in which they are located. Slope instability created water-bodies mainly located at lower altitudes (2842 m mean altitude), representing tectonic weak zones or accumulation of debris, which are influenced by intense slope dynamics. These water-bodies are therefore more fragile, and their existence is probably more short-lived than that of bodies created under glacial conditions.

scholarly journals Metabolome Shift in Both Metastatic Breast Cancer Cells and Astrocytes Which May Contribute to the Tumor Microenvironment

2021 ◽  
Vol 22 (14) ◽  
pp. 7430
Author(s):  
Hiromi Sato ◽  
Ayaka Shimizu ◽  
Toya Okawa ◽  
Miaki Uzu ◽  
Momoko Goto ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Metastatic Breast ◽  
Principal Component ◽  
Pentose Phosphate ◽  
Metastatic Brain Tumors ◽  
Pentose Phosphate Pathways ◽  
Culture Supernatants

The role of astrocytes in the periphery of metastatic brain tumors is unclear. Since astrocytes regulate central nervous metabolism, we hypothesized that changes in astrocytes induced by contact with cancer cells would appear in the metabolome of both cells and contribute to malignant transformation. Coculture of astrocytes with breast cancer cell supernatants altered glutamate (Glu)-centered arginine–proline metabolism. Similarly, the metabolome of cancer cells was also altered by astrocyte culture supernatants, and the changes were further amplified in astrocytes exposed to Glu. Inhibition of Glu uptake in astrocytes reduces the variability in cancer cells. Principal component analysis of the cancer cells revealed that all these changes were in the first principal component (PC1) axis, where the responsible metabolites were involved in the metabolism of the arginine–proline, pyrimidine, and pentose phosphate pathways. The contribution of these changes to the tumor microenvironment needs to be further pursued.

scholarly journals Reconstruction of river valley evolution before and after the emplacement of the giant Seymareh rock avalanche (Zagros Mts., Iran)

2019 ◽  
Vol 7 (4) ◽  
pp. 929-947 ◽  
Author(s):  
Michele Delchiaro ◽  
Marta Della Seta ◽  
Salvatore Martino ◽  
Maryam Dehbozorgi ◽  
Reza Nozaem
Keyword(s):  
Slope Failure ◽  
Rock Avalanche ◽  
Evolutionary Model ◽  
River Valley ◽  
Time To Failure ◽  
Stress Release ◽  
Seismic Triggering ◽  
Rock Creep ◽  
Before And After

Abstract. The Seymareh landslide, detached ∼10 ka from the northeastern flank of the Kabir-kuh fold (Zagros Mts., Iran), is recognized worldwide as the largest rock slope failure (44 Gm3) ever recorded on the exposed Earth surface. Detailed studies have been performed that have described the landslide mechanism and different scenarios have been proposed for explaining the induced landscape changes. The purpose of this study is to provide still missing time constraints on the evolution of the Seymareh River valley, before and after the emplacement of the Seymareh landslide, to highlight the role of geomorphic processes both as predisposing factors and as response to the landslide debris emplacement. We used optically stimulated luminescence (OSL) to date lacustrine and fluvial terrace sediments, whose plano-altimetric distribution has been correlated to the detectable knickpoints along the Seymareh River longitudinal profile, allowing the reconstruction of the evolutionary model of the fluvial valley. We infer that the knickpoint migration along the main river and the erosion wave propagation upstream through the whole drainage network caused the stress release and the ultimate failure of the rock mass involved in the landslide. We estimated that the stress release activated a mass rock creep (MRC) process with gravity-driven deformation processes occurring over an elapsed time-to-failure value on the order of 102 kyr. We estimated also that the Seymareh damming lake persisted for ∼3500 years before starting to empty ∼6.6 ka due to lake overflow. A sedimentation rate of 10 mm yr−1 was estimated for the lacustrine deposits, which increased up to 17 mm yr−1 during the early stage of lake emptying due to the increased sediment yield from the lake tributaries. We calculated an erosion rate of 1.8 cm yr−1 since the initiation of dam breaching by the Seymareh River, which propagated through the drainage system up to the landslide source area. The evolutionary model of the Seymareh River valley can provide the necessary constraints for future stress–strain numerical modeling of the landslide slope to reproduce the MRC and demonstrate the possible role of seismic triggering in prematurely terminating the creep-controlled time-to-failure pathway for such an extremely large case study.

Landslide susceptibility in a mountainous geoecosystem, Tijuca Massif, Rio de Janeiro: The role of morphometric subdivision of the terrain

Geomorphology ◽  
2007 ◽  
Vol 87 (3) ◽  
pp. 120-131 ◽  
Author(s):  
Ana Luiza Coelho-Netto ◽  
André S. Avelar ◽  
Manoel C. Fernandes ◽  
Willy A. Lacerda
Keyword(s):  
Landslide Susceptibility ◽  
Rio De Janeiro
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