The July 2015 Debris flow in Barsem, Western Pamir (GBAO) Tajikistan: Description and causes

Tajikistan is a landlocked country in the Central Asia republics of the former Soviet Union. Tajikistan is prone to many natural disasters. Most commonly in Tajikistan, mudflows occur in the South and North parts of the country. The 2015 Barsem mudflow caused significant damage to the entire village, a territory of the Western Pamir Gorno-Badakhshan Autonomous Region (GBAO), Tajikistan; fortunately, no human casualties. The total volume of debris flow is about 4.9 million m3. Typically, precipitation above 15-20mm per day in arid areas causes mudflow. Accumulated water during the intensive melting of the glacier and snowfields was saturated with water by the moraine sediment blocking its paths (which served as a dam for the lake that formed). Several studies indicate that mudflow triggers excess pore pressure or liquefaction of the soil; consequently, sudden and high shear resistance losses eventually generate a mudflow [5][6]. Although mudflows and landslides occur annually, after the 2015 Barsem mudflow, it becomes clear that the intensity and frequency of new events are increasing. Consequently, the author strongly believes establishing and implementing an early warning system can be essential

Estudio del mecanismo de falla de terraplenes debido a la infiltración de aguas lluvias mediante el monitoreo de presiones de poros y contenidos de agua

El presente artículo muestra experimentos realizados utilizando modelos a escala para estudiar el proceso de infiltración en terraplenes sometidos a aguas lluvias. Varios modelos a escala fueron construidos usando un suelo arenoso con alto contenido de finos; para aplicar la lluvia artificial y observar el proceso de infiltración del agua se utilizó un tubo de irrigación. Para monitorear los cambios en succión ocasionados por los ciclos de humedecimiento y secado se instalaron dentro del suelo varios sensores de presión de poros, contenido de agua y de desplazamiento en diferentes puntos. El cambio de la presión de poros en el tiempo, el contenido de agua y las relaciones entre las mediciones de presión de poros y desplazamientos del suelo son presentados. Este estudio muestra que el movimiento del suelo en un talud está directamente relacionado con el contenido de agua del suelo y las presiones de poros existentes en él, sugiriendo que por medio del monitoreo de estos dos parámetros es posible predecir fallas locales inducidas por infiltración de aguas lluvias en los talude

Association Analysis of Nuclear Receptor Rev-erb Alpha Gene (NR1D1) and Japanese Methamphetamine Dependence

Several investigations suggested abnormalities in circadian rhythms are related to the pathophysiology of psychiatric disorders, including drug addiction. Recently, orphan nuclear receptor rev-erb alpha and glycogen synthase kinase-3 β (GSK-3β) were shown to be important circadian components. In addition, the orphan nuclear receptor rev-erb alpha is a key negative feedback regulator of the circadian clock. These evidences indicate that rev-erb alpha gene (NR1D1) is a good candidate gene for the pathogenesis of methamphetamine dependence. To evaluate the association between NR1D1 and methamphetamine dependence, we conducted a case-control study of Japanese samples (215 methamphetamine dependence and 232 controls) with three tagging SNPs selected by HapMap database. Written informed consent was obtained from each subject. This study was approved by the ethics committees at Fujita Health University, Nagoya University Graduate School of Medicine and each participating member of the Institute of the Japanese Genetics Initiative for Drug Abuse (JGIDA). We did not detect an association between NR1D1 and Japanese methamphetamine dependence patients in allele/genotype-wise analysis, or the haplotype analysis. Our findings suggest that NR1D1 does not play a major role in the pathophysiology of methamphetamine dependence in the Japanese population

Genetic Association Analysis of NOS1 and Methamphetamine-Induced Psychosis Among Japanese

The neuronal nitric oxide synthase gene (NOS1) is located at 12q24, a susceptibility region for schizophrenia, and produces nitric oxide (NO). NO has been reported to play important roles as a gaseous neurotransmitter in brain. NO is a second messenger for the N-methyl-D aspartate (NMDA) receptor and is related to the dopaminergic system. Because the symptomatology of methamphetamine (METH) use disorder patients with psychosis is similar to that of patients with schizophrenia, NOS1 is a good candidate gene for METH-induced psychosis. Therefore, we conducted a case-control association study between NOS1 and METH-induced psychosis with Japanese subjects (183 with METH-induced psychosis patients and 519 controls). We selected seven SNPs (rs41279104, rs3782221, rs3782219, rs561712, rs3782206, rs6490121, rs2682826) in NOS1 from previous reports. Written informed consent was obtained from each subject. This study was approved by the Ethics Committee at Fujita Health University School of Medicine and each participating institute of the Japanese Genetics Initiative for Drug Abuse (JGIDA). No significant association was found between NOS1 and METH-induced psychosis in the allele/genotype-wise or haplotype-wise analyses. In conclusion, we suggest that NOS1 might not contribute to the risk of METH-induced psychosis in the Japanese population

Investigation on parameters used in warning systems for rain-induced embankment instability

A number of instrumented laboratory-scale soil embankment slopes were subjected to artificial rainfall until they failed. The factor of safety of the slope based on real-time measurements of pore-water pressure (suction) and laboratory measured soil properties were calculated as the rainfall progressed. Based on the experiment measurements and slope stability analysis, it was observed that slope displacement measurements can be used to warn the slope failure more accurately. Further, moisture content/pore-water pressure measurements near the toe of the slope and the real-time factor of safety can also be used for prediction of rainfall-induced embankment failures with adequate accuracy

Effects of dry density and grain size distribution on soil-water characteristic curves of sandy soils

The unsaturated soil mechanics is receiving increasing attention from researchers and as well as from practicing engineers. However, the requirement of sophisticated devices to measure unsaturated soil properties and time consumption have made the geotechnical engineers keep away from implication of the unsaturated soil mechanics for solving practical geotechnical problems. The application of the conventional laboratory devices with some modifications to measure unsaturated soil properties can promote the application of unsaturated soil mechanics into engineering practice. Therefore, in the present study, a conventional direct shear device was modified to measure unsaturated shear strength parameters at low suction. Specially, for the analysis of rain-induced slope failures, it is important to measure unsaturated shear strength parameters at low suction where slopes become unstable. The modified device was used to measure unsaturated shear strength of two silty soils at low suction values (0 ~ 50 kPa) that were achieved by following drying path and wetting path of soil-water characteristic curves (SWCCs) of soils. The results revealed that the internal friction angle of soil was not significantly affected by the suction and as well as the drying-wetting SWCCs of soils. The apparent cohesion of soil increased with a decreasing rate as the suction increased. Further, the apparent cohesion obtained from soil in wetting was greater than that obtained from soil in drying. Shear stress-shear displacement curves obtained from soil specimens subjected to the same net normal stress and different suction values showed a higher initial stiffness and a greater peak stress as the suction increased. In addition, it was observed that soil became more dilative with the increase of suction. A soil in wetting exhibited slightly higher peak shear stress and more contractive volume change behaviour than that of in drying at the same net normal stress and the suction

Effects of slope inclination on the rain-induced instability of embankment slopes

Rainfall has been identified as one of the main causes for embankment failures in areas where high annual rainfall is experienced. The inclination of the embankment slope is important for its stability during rainfall. In this study, instrumented model embankments were subjected to artificial rainfalls to investigate the effects of the slope inclination on their stability. The results of the study suggested that when the slope inclination is greater than the friction angle of the soil, the failure is initiated by the loss of soil suction and when it is smaller than the friction angle of the soil, the failure is initiated by the positive pore water pressure developed at the toe of the slope. Further, slopes become more susceptible to sudden collapse during rainfall as the slope angle increases

The July 2015 Debris flow in Barsem, Western Pamir (GBAO) Tajikistan: Description and causes

Tajikistan is a landlocked country in the Central Asia republics of the former Soviet Union. Tajikistan is prone to many natural disasters. Most commonly in Tajikistan, mudflows occur in the South and North parts of the country. The 2015 Barsem mudflow caused significant damage to the entire village, a territory of the Western Pamir Gorno-Badakhshan Autonomous Region (GBAO), Tajikistan; fortunately, no human casualties. The total volume of debris flow is about 4.9 million m3. Typically, precipitation above 15-20mm per day in arid areas causes mudflow. Accumulated water during the intensive melting of the glacier and snowfields was saturated with water by the moraine sediment blocking its paths (which served as a dam for the lake that formed). Several studies indicate that mudflow triggers excess pore pressure or liquefaction of the soil; consequently, sudden and high shear resistance losses eventually generate a mudflow [5][6]. Although mudflows and landslides occur annually, after the 2015 Barsem mudflow, it becomes clear that the intensity and frequency of new events are increasing. Consequently, the author strongly believes establishing and implementing an early warning system can be essential