Catastrophic Ice-Debris Flow in the Rishiganga River, Chamoli, Uttarakhand (India)

A catastrophic flood occurred on 7 February 2021 around 10:30 AM (local time) in the Rishiganga River, which has been attributed to a rockslide in the upper reach of the Raunthi River. The Resourcesat 2 LISS IV (8 February 2021) and CNES Airbus satellite imagery (9 February 2021) clearly show the location of displaced materials. The solar radiation observed was higher than normal by 10% and 25% on 6 and 7 February 2021, respectively, however, the temperature shows up to 34% changes. These conditions are responsible for the sudden change in instability in glacier blocks causing deadly rock-ice slides that led to the collapse of the hanging glacier as a wedge failure. The displaced materials mixed with ice, snow, and debris caused catastrophic floods downstream within no time that destroyed critical infrastructure and killed human lives. The hydrodynamic modelling (HEC-RAS software) shows mean flow velocity up to 22.4 ± 8.6 m/s with an average depth of 16.3 ± 6.5 m that caused deadly devastation in the source region and along the rivers due to the flow of water in the valley

Effective Multiple Image Watermarking based on Dither Quantization

ABSTRAC

Study and Comparison Performance of On-demand AODV and DSR, along with the traditional proactive DSDV Routing Protocols for MANET

Abstract- In wireless research area, efficient routing algorithms can provide remarkable benefits in Ad-hoc networks, including higher throughput, lower average end-to-end delay, less number of dropped data packets and generally an ameliorated network performance. Many routing protocols for such networks have been proposed so far. My research work, an attempt has been made to compare the performance of three prominent on-demand reactive routing protocols for mobile ad hoc networks: DSR and AODV, along with the traditional proactive DSDV protocol. A simulation analysis with MAC and physical layer models is used to study interlayer communication and their performance implications. Experimental results obtained, showed that the On-demand protocols, AODV and DSR perform much better than the table-driven DSDV protocol. Although DSR and AODV share similar On-demand behavior, the differences in the protocol mechanics can lead to significant performance differentials. For a variety of scenarios, as characterized by mobility, load and size of the ad-hoc network were simulated. The performance differentials are analyzed using varying network load, mobility pattern, and Network size

An unsuspected foreign body: How we managed it

Ingestion or inhalation of foreign bodies can prove to be a diagnostic challenge. Unexplained throat pain and acute onset of dysphagia in an elderly patient should alert the clinician to the possibility of accidental foreign body ingestion. A patient presented with complaints of sudden onset of difficulty and pain in swallowing associated with ear pain, neck pain, and hypersalivation. The examination was within normal limits. It was on radiology that the suspicion of a foreign body was aroused. During esophagoscopy, an unsuspecting foreign body was discovered; a lower partial denture, swallowed unknowingly by the patient four days previously. Postoperatively the patient was stable. The case demonstrates how the clinician must have a high index of suspicion of foreign body ingestion, should a patient present with such symptoms. It also demonstrates the need for immediate and prompt intervention in order to prevent progression to fatal complications

Land Use Dynamics and Impact on Regional Climate Post-Tehri Dam in the Bhilangana Basin, Garhwal Himalaya

Land use and land cover (LULC) changes are a dynamic process determined by natural factors as well as the degree of human interaction in spatial and temporal perspectives. The present study focuses on analysing the LULC changes in the Bhilangana basin post-Tehri dam construction in the Garhwal Himalaya. Landsat series satellite images were used for three time periods to quantify spatial and temporal changes in the LULC using unsupervised classification techniques. The calculations of the areal coverage and change detection were carried out using the ArcGIS 10.3 software. The study finds that LULC changes were observed in the area surrounding the Tehri reservoir. The area under forest cover decreased by 54.71 km2, which is −5.7% of the geographical area, followed by agricultural land by 6.06 km2 (−0.4%) and scrubland and grass cover by 4.23 km2 (−0.28%) during the decade 2000 to 2010. Gradually, due to compensatory afforestation, forest cover increased by 5.65% in the period 2010–2020. A significant relationship with climatic variability is also established with LULC change in the region. The presence of a large water surface at a high altitude modified the albedo and air temperature and increased the atmospheric humidity and precipitation pattern. This study would be vital in understanding the climatic variability in the Himalayas and its impact on the community, environment and climate