135 research outputs found
Assessment of the performance of X-band satellite radar data for landslide mapping and monitoring: Upper Tena Valley case study.
Abstract. The aim of this work is to analyse the advantages and disadvantages of using the new X-band SAR data acquired by TerraSAR-X sensors for landslides mapping. This dataset has been processed using a Persistent Scatterer Interferometry technique over the Upper Tena Valley (Central Pyrenees, Spain). In the first section, the geological and geomorphological setting of the study area is introduced, focusing on the description of the landslide inventory. Then the Stable Point Network technique is briefly described, followed by the assessment of the performance of the X-band SAR dataset. In this context, we present first a model to predict the distribution of Persistent Scatterers based on the slope geometry and the land use information, which has then been validated with X-band data results. On a second stage, we have assessed the performance of X-band dataset to detect and monitor mapped landslides. Finally some illustrative case studies are shown demonstrating the potential of using X-band SAR data not only for landslide mapping but also to detect and monitor deformations affecting human infrastructures
Semi-automatic mapping of shallow landslides using free Sentinel-2 images and Google Earth Engine
The global availability of Sentinel-2 data and the widespread coverage of cost-free and high-resolution images nowadays give opportunities to map, at a low cost, shallow landslides triggered by extreme events (e.g. rainfall, earthquakes). Rapid and low-cost shallow landslide mapping could improve damage estimations, susceptibility models and land management.
This work presents a two-phase procedure to detect and map shallow
landslides. The first is a semi-automatic methodology allowing for mapping
potential shallow landslides (PLs) using Sentinel-2 images. The PL aims to
detect the most affected areas and to focus on them an high-resolution mapping and further investigations. We create a GIS-based and user-friendly methodology to extract PL based on pre- and post-event normalised difference vegetation index (NDVI) variation and
geomorphological filtering. In the second phase, the semi-automatic
inventory was compared with a benchmark landslide inventory drawn on
high-resolution images. We also used Google Earth Engine scripts to
extract the NDVI time series and to make a multi-temporal analysis.
We apply this procedure to two study areas in NW Italy, hit in 2016 and 2019 by extreme rainfall events. The results show that the semi-automatic mapping based on Sentinel-2 allows for detecting the majority of shallow landslides larger than satellite ground pixel (100 m2). PL density and distribution match well with the benchmark. However, the false positives (30 % to 50 % of cases) are challenging to filter, especially when they
correspond to riverbank erosions or cultivated land.</p
Assessment of the performance of X-band satellite radar data for landslide mapping and monitoring: Upper Tena Valley case study
The aim of this work is to analyse the advantages and disadvantages of using the new X-band SAR data acquired by TerraSAR-X sensors for landslides mapping. This dataset has been processed using a Persistent Scatterer Interferometry technique over the Upper Tena Valley (Central Pyrenees, Spain). In the first section, the geological and geomorphological setting of the study area is introduced, focusing on the description of the landslide inventory. Then the Stable Point Network technique is briefly described, followed by the assessment of the performance of the X-band SAR dataset. In this context, we present first a model to predict the distribution of Persistent Scatterers based on the slope geometry and the land use information, which has then been validated with X-band data results. On a second stage, we have assessed the performance of X-band dataset to detect and monitor mapped landslides. Finally some illustrative case studies are shown demonstrating the potential of using X-band SAR data not only for landslide mapping but also to detect and monitor deformations affecting human infrastructures
Az elĹ‘szerzĹ‘dĂ©s, mint a jövĹ‘beli ismĂ©telt foglalkoztatás jogi keretbe foglalt ĂgĂ©rete
Abstract: In this paper a methodology is proposed to elaborate landslide activity maps through the use of PS (Persistent Scatterer) data. This is illustrated through the case study of Tramuntana Range in the island of Majorca (Spain), where ALOS (Advanced Land Observing Satellite) images have been processed through a Persistent Scatterer Interferometry (PSI) technique during the period of 2007–2010. The landslide activity map provides, for every monitored landslide, an assessment of the PS visibility according to the relief, land use, and satellite acquisition parameters. Landslide displacement measurements are projected along the steepest slope, in order to compare landslide velocities with different slope orientations. Additionally, a ground motion activity map is also generated, based on active PS clusters not included within any known landslide phenomenon, butRemote Sens. 2013, 5 6199 even moving, potentially referred to unmapped landslides or triggered by other kinds o
Twenty-year advanced DInSAR analysis of severe land subsidence: The Alto Guadalentin Basin (Spain) case study
A twenty-year period of severe land subsidence evolution in the Alto Guadalentin Basin (southeast Spain) is monitored using multi-sensor SAR images, processed by advanced differential interferometric synthetic aperture radar (DInSAR) techniques. The SAR images used in this study consist of four datasets acquired by ERS-1/2, ENVISAT, ALOS and COSMO-SkyMed satellites between 1992 and 2012. The integration of ground surface displacement maps retrieved for different time periods allows us to quantify up to 2.50 m of cumulated displacements that occurred between 1992 and 2012 in the Alto Guadalentin Basin. DInSAR results were locally compared with global positioning system (GPS) data available for two continuous stations located in the study area, demonstrating the high consistency of local vertical motion measurements between the two different surveying techniques. An average absolute error of 4.6 +/- 4 mm for the ALOS data and of 4.8 +/- 3.5 mm for the COSMO-SkyMed data confirmed the reliability of the analysis. The spatial analysis of DInSAR ground surface displacement reveals a direct correlation with the thickness of the compressible alluvial deposits. Detected ground subsidence in the past 20 years is most likely a consequence of a 100-200 m groundwater level drop that has persisted since the 1970s due to the overexploitation of the Alto Guadalentin aquifer system. The negative gradient of the pore pressure is responsible for the extremely slow consolidation of a very thick (> 100 m) layer of fine-grained silt and clay layers with low vertical hydraulic permeability (approximately 50 mm/h) wherein the maximum settlement has still not been reached. (C) 2015 Published by Elsevier B.V
Application of multi-sensor advanced DInSAR analysis to severe land subsidence recognition: Alto GuadalentĂn Basin (Spain)
Multi-sensor advanced DInSAR analyses have been performed and compared with
two GPS station measurements, in order to evaluate the land subsidence
evolution in a 20-year period, in the Alto GuadalentĂn Basin where the
highest rate of man-induced subsidence (> 10 cm yr−1) of
Europe had been detected. The control mechanisms have been examined
comparing the advanced DInSAR data with conditioning and triggering factors
(i.e. isobaths of Plio-Quaternary deposits, soft soil thickness and
piezometric level)
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Review of battery electric vehicle propulsion systems incorporating flywheel energy storage
The development of battery electric vehicles (BEV) must continue since this can lead us towards a zero emission transport system. There has been an advent of the production BEVs in recent years; however their low range and high cost still remain the two important drawbacks. The battery is the element which strongly affects the cost and range of the BEV. The batteries offer either high specific power or high specific energy but not both. To provide the BEVs with the characteristic to compete with conventional vehicles it is beneficial to hybridize the energy storage combining a high energy battery with a high power source. This shields the battery from peak currents and improves its capacity and life. There are various devices which could qualify as a secondary storage system for the BEV such as high power battery, supercapacitor and high speed flywheel (FW). This paper aims to review a specific type of hybridisation of energy storage which combines batteries and high speed flywheels. The flywheel has been used as a secondary energy system in BEVs from the early 1970s when the oil crises triggered an interest in BEVs. Since the last decade the interest in flywheels has strengthened and their application in the kinetic energy recovery system (KERS) in Formula 1 has further bolstered the case for flywheels. With a number of automotive manufacturers getting involved in developing flywheels for road applications, the authors believe commercial flywheel based powertrains are likely to be seen in the near future. It is hence timely to produce a review of research and development in the area of flywheel assisted BEVs
Kinase-Impaired BTK Mutations Are Susceptible to Clinical-Stage BTK and IKZF1/3 Degrader NX-2127
INTRODUCTION: Bruton’s tyrosine kinase (BTK) is a nonreceptor kinase in the B cell receptor (BCR) signaling cascade critical for B cell survival. As such, chronic lymphocytic leukemia (CLL) and other B cell cancers are sensitive to inhibition of BTK. Covalent and noncovalent inhibitors of BTK have revolutionized the treatment of these cancers. Therefore, understanding mechanisms by which acquired mutation in BTK confer drug resistance and developing new therapies to overcome resistance are critically important. RATIONALE: We recently discovered BTK mutations that confer resistance across covalent and noncovalent BTK inhibitors. In this study, we found that a group of these mutants impair BTK kinase activity despite still enabling downstream BCR signaling. We therefore set out to understand the nonenzymatic functions of BTK and explored targeted protein degradation to overcome the oncogenic scaffold function of mutant BTK. This effort included evaluation of BTK degradation in patients with CLL treated in a phase 1 clinical trial of NX-2127, a first-in-class BTK degrader (NCT04830137). RESULTS: BTK enzymatic activity assays revealed that drug resistance mutations in BTK fall into two distinct groups: kinase proficient and kinase impaired. Immunoprecipitation mass spectrometry of kinase-impaired BTK L528W (Leu528→Trp) revealed a scaffold function of BTK with downstream signaling and survival dependent on surrogate kinases that bind to kinase-impaired BTK proteoforms. To target the nonenzymatic functions of BTK, we developed NX-2127, a heterobifunctional molecule that engages the ubiquitin-proteasome system to simultaneously bind both BTK and the cereblon E3 ubiquitin ligase complex, inducing polyubiquitination and proteasome-dependent degradation of IKZF1/3 and all recurrent drug-resistant forms of mutant BTK. The activity of NX-2127 on BTK degradation was further demonstrated in patients with CLL treated in a phase 1 clinical trial of NX-2127, where \u3e80% BTK degradation was achieved and clinical responses were also seen in 79% of evaluable patients, independent of mutant BTK genotypes. CONCLUSION: We identified that BTK inhibitor resistance mutations fall into two distinct functional categories. Kinase-impaired BTK mutants disable BTK kinase activity while promoting physical interactions with other kinases to sustain downstream BCR signaling. This scaffold function of BTK was disrupted by NX-2127, a potent BTK degrader, which showed promising responses for patients with relapsed and refractory CLL, independently of mutant BTK functional category
Mechanisms of Resistance to Noncovalent Bruton's Tyrosine Kinase Inhibitors
Background Covalent (irreversible) Bruton's tyrosine kinase (BTK) inhibitors have transformed the treatment of multiple B-cell cancers, especially chronic lymphocytic leukemia (CLL). However, resistance can arise through multiple mechanisms, including acquired mutations in BTK at residue C481, the binding site of covalent BTK inhibitors. Noncovalent (reversible) BTK inhibitors overcome this mechanism and other sources of resistance, but the mechanisms of resistance to these therapies are currently not well understood. Methods We performed genomic analyses of pretreatment specimens as well as specimens obtained at the time of disease progression from patients with CLL who had been treated with the noncovalent BTK inhibitor pirtobrutinib. Structural modeling, BTK-binding assays, and cell-based assays were conducted to study mutations that confer resistance to noncovalent BTK inhibitors. Results Among 55 treated patients, we identified 9 patients with relapsed or refractory CLL and acquired mechanisms of genetic resistance to pirtobrutinib. We found mutations (V416L, A428D, M437R, T474I, and L528W) that were clustered in the kinase domain of BTK and that conferred resistance to both noncovalent BTK inhibitors and certain covalent BTK inhibitors. Mutations in BTK or phospholipase C gamma 2 (PLCÎł2), a signaling molecule and downstream substrate of BTK, were found in all 9 patients. Transcriptional activation reflecting B-cell-receptor signaling persisted despite continued therapy with noncovalent BTK inhibitors.Conclusions Resistance to noncovalent BTK inhibitors arose through on-target BTK mutations and downstream PLCÎł2 mutations that allowed escape from BTK inhibition. A proportion of these mutations also conferred resistance across clinically approved covalent BTK inhibitors. These data suggested new mechanisms of genomic escape from established covalent and novel noncovalent BTK inhibitors. (Funded by the American Society of Hematology and others.
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