scholarly journals Abnormal Strain Induced by Heavy Rainfall on Borehole Strainmeters Observed in Taiwan

2021 ◽  
Vol 11 (3) ◽  
pp. 1301
Author(s):  
Chih-Yen Chen ◽  
Jyr-Ching Hu ◽  
Chi-Ching Liu ◽  
Chun-Ying Chiu
Keyword(s):  
Debris Flow ◽  
Heavy Rainfall ◽  
Quick Response ◽  
River Channels ◽  
Response Curves ◽  
Mountain Areas ◽  
Vertical Coupling ◽  
Cumulative Rainfall ◽  
Strain Data ◽  
The Hill

We found some obvious abnormal strain induced by heavy rainfall from borehole strainmeters deployed in Western Taiwan. The strain induced by rainfall can be divided into two parts, one is the quick response for extra loads of rainwater on the ground, and another one is the slow response for rainwater infiltrating into the strata. The quick and slow rainfall responses of areal strain data are analyzed using the technique of recursive digital filtering. Moreover, the rainfall impact functions of the studied stations are calculated using deconvolution. We found, in most cases, the response strain will reach the maximum in half an hour after heavy rainfall, and then show an exponential decay, it might persist more than 200 h depending on the hydrogeological condition around the station. Whereas the river flowing beside the station will help accelerating the runoff dispersion and reducing rainfall decay time in the hill or mountain region. We also compare the results after calibration in term of isotropic and vertical coupling individually. We found that the response strains are smaller in vertical coupling rather than isotropic coupling. The effects of debris avalanches caused by intensive rainfall in the mountain areas can be viewed as two types of rock deformation: generated only under the influence of rainfall and generated by the increased load in the river channels due to rainfall-induced landslides or debris flow. When the cumulative rainfall exceeds a certain threshold, the strain response curves show a noticeable anomaly likely due to the effects of the debris flow events in places prone to landslides.

scholarly journals 2D Runout Modelling of Hillslope Debris Flows, Based on Well-Documented Events in Switzerland

Geosciences ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 70 ◽  
Author(s):  
Florian Zimmermann ◽  
Brian W. McArdell ◽  
Christian Rickli ◽  
Christian Scheidl
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Mass Movement ◽  
Clay Content ◽  
Systematic Evaluation ◽  
Mountain Areas ◽  
Flow Processes ◽  
Friction Parameters ◽  
Cohesive Interaction ◽  
Hillslope Debris Flow

In mountain areas, mass movements, such as hillslope debris flows, pose a serious threat to people and infrastructure, although size and runout distances are often smaller than those of debris avalanches or in-channel-based processes like debris floods or debris flows. Hillslope debris-flow events can be regarded as a unique process that generally can be observed at steep slopes. The delimitation of endangered areas and the implementation of protective measures are therefore an important instrument within the framework of a risk analysis, especially in the densely populated area of the alpine region. Here, two-dimensional runout prediction methods are helpful tools in estimating possible travel lengths and affected areas. However, not many studies focus on 2D runout estimations specifically for hillslope debris-flow processes. Based on data from 19 well-documented hillslope debris-flow events in Switzerland, we performed a systematic evaluation of runout simulations conducted with the software Rapid Mass Movement Simulation: Debris Flow (RAMMS DF)—a program originally developed for runout estimation of debris flows and snow avalanches. RAMMS offers the possibility to use a conventional Voellmy-type shear stress approach to describe the flow resistance as well as to consider cohesive interaction as it occurs in the core of dense flows with low shear rates, like we also expect for hillslope debris-flow processes. The results of our study show a correlation between the back-calculated dry Coulomb friction parameters and the percentage of clay content of the mobilised soils. Considering cohesive interaction, the performance of all simulations was improved in terms of reducing the overestimation of the observed deposition areas. However, the results also indicate that the parameter which accounts for cohesive interaction can neither be related to soil physical properties nor to different saturation conditions.

scholarly journals The polyaminoisoprenyl potentiator NV716 revives old disused antibiotics against intracellular forms of infection by Pseudomonas aeruginosa

2020 ◽  
pp. AAC.02028-20
Author(s):  
Gang W. Wang ◽  
Jean-Michel Brunel ◽  
Jean-Michel Bolla ◽  
Françoise Van Bambeke
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Efflux Pump ◽  
Hill Equation ◽  
Intrinsic Resistance ◽  
Bacterial Persistence ◽  
Response Curves ◽  
Active Efflux ◽  
Efflux Pump Inhibitors ◽  
The Hill ◽  
Multiple Antibiotics

Active efflux confers intrinsic resistance to multiple antibiotics in Pseudomonas aeruginosa, including old disused molecules. Beside resistance, intracellular survival is another reason for failure to eradicate bacteria with antibiotics. We evaluated the capacity of polyaminoisoprenyl potentiators (designed as efflux pump inhibitors [EPIs]) NV716 and NV731 compared to PAβN to restore the activity of disused antibiotics (doxycycline, chloramphenicol [substrates for efflux], rifampin [not substrate]) in comparison with ciprofloxacin against intracellular P. aeruginosa (strains with variable efflux levels) in THP-1 monocytes exposed during 24h to antibiotics alone (0.003-100x MIC) or combined with EPIs. Pharmacodynamic parameters (apparent static concentrations [Cs]; maximal relative efficacy [Emax]) were calculated using the Hill equation of concentration-response curves. PAβN and NV731 moderately reduced (0-4 doubling dilutions) antibiotic MICs but did not affect their intracellular activity. NV716 markedly reduced (1-16 doubling dilutions) the MIC of all antibiotics (substrates or not for efflux; strains expressing efflux or not); it improved their relative potency and maximal efficacy (lower Cs; more negative Emax) intracellularly. In parallel, NV716 reduced the persister fraction in stationary cultures when combined with ciprofloxacin. In contrast to PAβN and NV731 that act as EPIs against extracellular bacteria only, NV716 can resensitize P. aeruginosa to antibiotics whether substrates or not for efflux, both extracellularly and intracellularly. This suggests a complex mode of action that goes beyond a simple inhibition of efflux and reduces bacterial persistence. NV716 may appear as a useful adjuvant, including to disused antibiotics with low antipseudomonal activity, to improve their activity, including against intracellular P. aeruginosa.

Heavy-rainfall-induced catastrophic rockslide-debris flow at Sanxicun, Dujiangyan, after the Wenchuan Ms 8.0 earthquake

Landslides ◽  
2015 ◽  
Vol 13 (1) ◽  
pp. 9-23 ◽  
Author(s):  
Yueping Yin ◽  
Yuliang Cheng ◽  
Jingtao Liang ◽  
Wenpei Wang
Keyword(s):  
Debris Flow ◽  
Heavy Rainfall ◽  
Wenchuan Ms 8.0 Earthquake

Simulating debris flows triggered by rainfall in Shiyang gully, China

2020 ◽  
Author(s):  
Jiaoyang Li
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Rainfall Intensity ◽  
Intensity Increase ◽  
Short Term ◽  
Rain Area ◽  
Cumulative Rainfall ◽  
Event Flow ◽  
Warning Time ◽  
Main Factor

<p>A debris flow occurred in Shiyang gully, located between Hebei Province and Beijing, on 8 June 2017, resulting in 6 people dead or injured. Short-term heavy rainfall is the main factor that triggered this event, however, the meteorological agency didn’t forecast this event very well. In this study, numerical simulation using FLO-2D was performed to reproduce the debris flow event (flow depths, flow velocities, and sediment depositions)occurred in 2017. The results of the field survey showed that the influential range of debris flow is consistent with the simulation results. Simulated depth accuracy is greater than 70%. Then, we used FLO-2D is calibrated to simulate debris flows disasters under different rainfall scenarios. The results showed that, the Beijing needs to be warned when the accumulated precipitation is 40mm at the rainfall intensity of 1mm/min. As cumulative rainfall and rainfall intensity increase, the risk of Shiyang gully is increasing.  This study used FLO-2D simulated process of debris flows triggered by rainfall. The results showed the early warning time and influential range for different intensity ,accumulated precipitation, and rain area, which is beneficial to the debris flow management in the western mountainous areas of Beijing.</p>

scholarly journals Pharmacodynamics of TRPV1 Agonists in a Bioassay Using Human PC-3 Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Daniel Alvarez-Berdugo ◽  
Marcel Jiménez ◽  
Pere Clavé ◽  
Laia Rofes
Keyword(s):  
Sensory Neurons ◽  
Fluorescence Emission ◽  
Hill Equation ◽  
Hill Coefficient ◽  
Response Curves ◽  
Trpv1 Receptor ◽  
Specific Antagonist ◽  
Emission Changes ◽  
The Hill

Purpose. TRPV1 is a multimodal channel mainly expressed in sensory neurons. We aimed to explore the pharmacodynamics of the TRPV1 agonists, capsaicin, natural capsaicinoids, and piperine in anin vitrobioassay using human PC-3 cells and to examine desensitization and the effect of the specific antagonist SB366791.Methods. PC-3 cells expressing TRPV1 were incubated with Fluo-4. Fluorescence emission changes following exposition to agonists with and without preincubation with antagonists were assessed and referred to maximal fluorescence following the addition of ionomycin. Concentration-response curves were fitted to the Hill equation.Results. Capsaicin and piperine had similar pharmacodynamics (Emax204.8 ± 184.3% piperine versus 176.6 ± 35.83% capsaicin,P=0.8814, Hill coefficient 0.70 ± 0.50 piperine versus 1.59 ± 0.86 capsaicin,P=0.3752). In contrast, capsaicinoids had lowerEmax(40.99 ± 6.14% capsaicinoids versus 176.6 ± 35.83% capsaicin,P<0.001). All the TRPV1 agonists showed significant desensitization after the second exposition and their effects were strongly inhibited by SB366791.Conclusion. TRPV1 receptor is successfully stimulated by capsaicin, piperine, and natural capsaicinoids. These agonists present desensitization and their effect is significantly reduced by a TRPV1-specific antagonist. In addition, PC-3 cell bioassays proved useful in the study of TRPV1 pharmacodynamics.

Cause Analysis of Zhaohe Debris Flow in Erlong Town in Zhenping County in Henan Province

2014 ◽  
Vol 638-640 ◽  
pp. 2071-2074
Author(s):  
Wei Zhang
Keyword(s):  
Debris Flow ◽  
Wide Distribution ◽  
Human Engineering ◽  
Mountain Areas ◽  
Flow Area ◽  
Cause Analysis ◽  
Climate Conditions ◽  
Neotectonic Movement ◽  
Engineering Activity ◽  
Steep Terrain

Debris flow is one of the major geological disasters in mountain areas. This paper systematically analyzes the influence of steep terrain conditions, the development of regional structure, neotectonic movement and earthquake, wide distribution of debris, human engineering activity and rainfall concentrated climate conditions in debris flow area. The dominant factors inducing Zhaohe debris flow were revealed, providing guidance for the debris flow disaster prevention, as well as reference for the same area debris flow cause analysis.

scholarly journals Horizontal channel development on the upper Jizera and the upper Vltava Rivers between 1938 and 2012

Geografie ◽  
2014 ◽  
Vol 119 (2) ◽  
pp. 105-125 ◽  
Author(s):  
Martin Hložek
Keyword(s):  
River Basin ◽  
Bohemian Massif ◽  
Natural Environments ◽  
River Channels ◽  
Mountain Areas ◽  
Channel Changes ◽  
Mountainous Regions ◽  
Lateral Erosion ◽  
Study Sites ◽  
Channel Development

Through the use of orthophotomaps from 1938 and 1952, this paper examines the development of horizontal channels of selected rivers in mountain areas of the Bohemian Massif. Two study sites in northern and southern part of Bohemian Massif were analysed in order to evaluate changes in river channels under similar natural conditions. Developments on the Upper Jizera River and its tributary, the Jizerka River, were investigated for the time period of 1938–2012. The Upper Vltava (Moldau) river, along with its tributaries, was studied in regards to developments taking place over the period of 1952–2012. Historical orthophotomaps were georeferenced and river banks were subsequently determined through the use of ArcGIS software. Both sites are situated in wide valleys with a low gradient, representing an exceptional relief in generally mountainous regions. Channel changes are documented via fluvial lakes, paleomeander remnants and meander cut-offs. Together with high precipitation rates in both basins, periods of extreme floodings seem to have a significant influence on channel development and transformation. Lateral erosion is somewhat less intense when compared to other rivers in similar natural environments across Central Europe. The estimated maximum lateral erosion in the Upper Jizera River basin is 0.5 m.year−1, whereas in the Vltava River basin, the lateral erosion reaches up to 1.1 m.year−1.

scholarly journals Flash flood and debris flow in the Harihara River, Kyushu, Japan

2000 ◽  
Vol 22 ◽  
Author(s):  
N. Gurung ◽  
A. Rahman ◽  
Y. Iwao
Keyword(s):  
Debris Flow ◽  
Heavy Rainfall ◽  
Flash Flood ◽  
Soil Mass ◽  
Field Investigation ◽  
Great Loss ◽  
Electrical Survey ◽  
Main Factors ◽  
Hidden Fault

The flash flood and debris flow after a heavy rainfall wiped out a village of southern Japan on the tragic midnight of 10 July 1997, and a great loss of property and lives took place in this ill-fated incident. After the heavy rainfall, the debris flow induced by a sudden flash flood took 21 lives in Southern Kyushu. Detailed field investigation, in situ survey, electrical survey, and hydrogeological analyses were conducted to find out the triggering factors of the disaster. The main factors of this disaster were a hidden fault and the perched groundwater. Moving soil mass downhill into the agricultural pond had triggered the flash flood. The details of sequential disaster events as perceived from the observation and analyses are presented in this paper.

Suppression by Zinc of AMPA Receptor-Mediated Synaptic Transmission in the Retina

2002 ◽  
Vol 88 (3) ◽  
pp. 1245-1251 ◽  
Author(s):  
Dao-Qi Zhang ◽  
Christophe Ribelayga ◽  
Stuart C. Mangel ◽  
Douglas G. McMahon
Keyword(s):  
Glutamate Receptor ◽  
Ampa Receptors ◽  
Bipolar Cells ◽  
Horizontal Cells ◽  
Hill Coefficient ◽  
Receptor Desensitization ◽  
Patch Clamp Recording ◽  
Response Curves ◽  
Peak Current ◽  
The Hill

Zinc is strikingly co-localized with glutamate-containing vesicles in the synaptic terminals of retinal photoreceptors, and it is thought to be co-released with glutamate onto postsynaptic neurons such as horizontal cells and bipolar cells. Here we examined exogenous zinc modulation of glutamate receptors on cultured retinal horizontal cells using patch-clamp recording and endogenous zinc effect on intact horizontal cells using intracellular recording techniques. Application of 3, 30, and 300 μM zinc reduced the whole cell peak current of response to 200 μM glutamate by 2, 30, and 56%, respectively. Zinc suppression of glutamate response persisted in the presence of 10 μM cyclothiazide (CTZ). Glutamate responses of outside-out patches were completely abolished by 30 μM 1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine (GYKI 52466), and the receptor desensitization was blocked by 30 μM CTZ, indicating that receptor target for the zinc action on horizontal cells is α-amino-3-hydroxy-5-methyl-4-isoxazoleproponic acid (AMPA) receptors. Zinc decreased the amplitude of outside-out patch peak current without an effect on either its 10–90% rise time or the rate of receptor desensitization. Dose-response curves for glutamate show that zinc reduced the maximal current evoked by glutamate and increased EC50 from 50 ± 3 to 70 ± 6 μM without changing the Hill coefficient. Chelation of endogenous zinc with 1 mM Ca-EDTA depolarized horizontal cells in the intact retina by 3 mV, consistent with relief of the partial glutamate receptor inhibition by zinc. Overall, the results describe a unimodal form of zinc modulation of AMPA-type glutamate receptor responses not previously described in native neuronal preparations and a novel role for endogenous zinc in modulating neurotransmission.

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