Geomorphology最新文献

{"title":"Geomorphologic mapping and analysis of fault activities along the northern margin of the Yanfan Basin, China","authors":"Jiajun Sun ,&nbsp;Honglin He ,&nbsp;Takashi Oguchi ,&nbsp;Zhanyu Wei ,&nbsp;Shuai Zhao ,&nbsp;Yueren Xu ,&nbsp;Yongqi Meng ,&nbsp;Xiaodi Tan","doi":"10.1016/j.geomorph.2024.109568","DOIUrl":"10.1016/j.geomorph.2024.109568","url":null,"abstract":"<div><div>The proximity of Beijing to active faults at the northeastern end of the Shanxi Rift System has heightened seismic concerns since the 1976 Tangshan <em>M</em> 7.8 earthquake. This study examines the 105-km-long northern margin fault of the Yanfan Basin in the rift system. Previous studies indicated that the alluvial fans and terraces along the fault have been displaced due to large earthquakes over the past ~30 ka. Analysis of 0.5 m resolution terrain data enabled the identification of six surface levels of alluvial fans and five river terraces. We measured 373 vertical displacements across these geomorphic features and grouped the distribution of these values into five categories based on their probability density. These groups correspond to repeated faulting events since ~14 ka, with data from prior paleoseismological studies aiding in dating these offsets. The most recent displacements are potentially linked to the 1484 <em>M</em> 6.8 Juyongguan and 1337 <em>M</em> 6.5 Huailai earthquakes. The ~2 m difference between the offset sets suggests that similar multiple seismic events could have caused each set. The empirical relationship between surface rupture length and earthquake magnitude for the recorded events indicates that the fault's complex geometry likely contributed to segmented ruptures during these events. This study highlights the need to scrutinize fault activity near densely populated regions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109568"},"PeriodicalIF":3.1,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ephemeral geomorphodiversity: Conceptual debate, valuation, and heritage management","authors":"Juan López Bedoya ,&nbsp;Raúl A. Mikkan ,&nbsp;Marcos Valcárcel Díaz","doi":"10.1016/j.geomorph.2024.109569","DOIUrl":"10.1016/j.geomorph.2024.109569","url":null,"abstract":"<div><div>This work engages in a discussion on the concept of the ephemeral and the active in Geomorphology, serving as the foundation to explore the potentiality of its heritage aspect. Commencing with conceptual aspects to reach a well-considered definition, an attempt is made to classify ephemeral phenomena from three perspectives: the chronological, based on the duration of landforms; that related to geomorphological dynamics; and the recurrence of the phenomena that modify them. The proposed objective is for this classification to define and differentiate various types of ephemeral geomorphological heritage, enabling their proper assessment and management from an original and specific perspective.</div><div>Subsequently, the article directs its attention to the keys that allow for the comprehension and organization of ephemeral geomorphological heritage resources. It advocates for focusing on the scientific significance of these phenomena rather than their formal appearance. Emphasis is placed on their role as indicators of environmental and climatic changes, in addition to their value for education and raising awareness about current and future environmental challenges.</div><div>The conclusion is reached that the treatment of these resources requires a strategy tailored to their essence, as their changing and mobile nature hinders the use of management plans successfully applied to other types of heritage. The key lies in understanding that the evolution of landforms and their dismantling are not synonymous with degradation but represent another facet of heritage value to be enhanced through innovative techniques. A final compendium establishes the foundations underpinning this specific strategy, seeking to elevate this heritage to a status on par with other well-established heritage categories within the realm of Geomorphology.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109569"},"PeriodicalIF":3.1,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analog modeling of landslide dynamics: Case study from the Andean Mesón Alto deposit, Central Chile (∼33°40′S)","authors":"L. Pinto ,&nbsp;S.A. Sepúlveda ,&nbsp;C. Lefeuvre ,&nbsp;C. Albornoz ,&nbsp;J. Rhodes ,&nbsp;P. Jara ,&nbsp;P. Muñoz ,&nbsp;K. Deckart","doi":"10.1016/j.geomorph.2024.109564","DOIUrl":"10.1016/j.geomorph.2024.109564","url":null,"abstract":"<div><div>The Mesón Alto deposit in the Central Chilean Andes (∼33°40′S) is a large-volume rock avalanche deposit (∼4.5 km³) formed in a glacial valley, presenting four distinct lithological bands whose origin is uncertain. This study employs analog modeling to investigate the influence of different kinematic variables on the deposit characteristics of landslides inspired in the Mesón Alto deposit. Field mapping has identified two primary lithological groups in the Mesón Alto deposit: andesitic fragments from the Oligo-Miocene formation and Miocene granodioritic rocks. The deposit displays a complex distribution of materials, including areas with well-sorted and poorly sorted deposits and varying grain sizes, from very large blocks to a locally significant presence of fine sediments. We developed analog models using a custom device that simulates the fluvial and glacial valley topography, varying factors such as valley geometry (U- or V-valley), opposite slope angles, and the number and proportion of landslide events. The measured parameters for comparisons included the deposit's width, length, and vertical and horizontal distances from the landslide crown to the toe. Our results highlight that variations in valley geometry and the number of events significantly influence the observed deposit structure. The study's findings provide insights into the dynamics of large-volume landslides and contribute to understanding the Mesón Alto deposit's formation. Results suggest that its complexity is primarily driven by a combination of geomorphological factors and the number of rock avalanche events: U-valley in confined conditions and two events, with the first larger than the second (70 %–30 %). Our results shed light on the processes shaping the Mesón Alto deposit and offer a framework for interpreting similar deposits in other glacial valleys worldwide, enhancing our understanding of variables that potentially influence the distribution and characteristics of landslide deposits in diverse settings.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109564"},"PeriodicalIF":3.1,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"When tableland flows: Insights from the east Patagonian landslide inventory","authors":"Tomáš Pánek ,&nbsp;Michal Břežný ,&nbsp;Jakub Kilnar ,&nbsp;Diego Winocur","doi":"10.1016/j.geomorph.2024.109567","DOIUrl":"10.1016/j.geomorph.2024.109567","url":null,"abstract":"<div><div>Landslides in volcanic and sedimentary tablelands encompass some of the world's largest subaerial landslide areas, yet the controls on their distribution and dominant landslide types remain unclear. Our landslide inventory across 517,000 km² of volcanic tableland in extra-Andean Patagonia reveals that, alongside common rotational slides and spreads forming nearly continuous fringes around plateaus, flow-type landslides dominated by earthflows are very common. Most of these flows are concentrated in the highest and most humid western part of the tableland, formerly covered by the Pleistocene Patagonian Ice Sheet (PIS), where they constitute three-quarters of the landslide area. Nevertheless, many of the longest flows (&gt;10 km) are located in the steepest parts of the tableland outside the PIS limits, paradoxically often in the driest areas. This suggests that these flows are inherited landforms originating during more humid Quaternary or older periods. Multivariate statistical analysis highlights that the distribution of flow-type landslides is largely influenced by caprock thickness. Decreasing caprock exposes larger areas of weak sub-caprock units such as sedimentary rocks and volcaniclastics on escarpments, thereby increasing the potential for viscoplastic flows. Future studies will require detailed exploration of the geomechanical properties of weak layers within sub-caprock units to achieve a comprehensive understanding of the lithological predisposition of flow-type landslides in the Patagonian tableland.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109567"},"PeriodicalIF":3.1,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The influence of grain size sorting on the roughness parametrization of gravel riverbeds","authors":"Ariel Henrique do Prado ,&nbsp;David Mair ,&nbsp;Philippos Garefalakis ,&nbsp;Beatriz C. Silveira ,&nbsp;Alexander C. Whittaker ,&nbsp;Fritz Schlunegger","doi":"10.1016/j.geomorph.2024.109565","DOIUrl":"10.1016/j.geomorph.2024.109565","url":null,"abstract":"<div><div>Grain size and surface roughness play crucial roles in modelling flow resistance and boundary shear stress in fluvial systems. However, the impact of grain size sorting on surface roughness, particularly for gravel-bed rivers composed of poorly-sorted sediments, has yet to be elucidated. Here we utilize a stochastic model to simulate generic riverbed surfaces, investigating the influence of sediment sorting on roughness. Through comparison with field-acquired data, we explore the relationships between grain size, sorting, presence of textural patches, and local roughness. Our analysis reveals significant spatial roughness variations on surfaces with poorer sorting conditions, driven by stochastic grain arrangements. Notably, surfaces with poorly sorted grains exhibit meter-scale patches, each with distinct roughness attributes. Consequently, upon characterizing the roughness of riverbeds made up of m-scale gravel bars, the sorting of the grains needs to be considered to account for the complexity of the relationships between water flow and riverbed.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109565"},"PeriodicalIF":3.1,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of forest fluvial geomorphological parameters through geospatial and machine learning approach for efficient watershed management","authors":"P. Ponnuchakkammal ,&nbsp;A. Raviraj ,&nbsp;D. Suresh Kumar ,&nbsp;Balaji Kannan ,&nbsp;C.S. Sumathi ,&nbsp;K. Boomiraj","doi":"10.1016/j.geomorph.2024.109561","DOIUrl":"10.1016/j.geomorph.2024.109561","url":null,"abstract":"<div><div>Forest watersheds, as providers of ecosystem services, are becoming increasingly vulnerable due to climate change. Urgent investigation and management of watershed parameters that are prioritized by sub-watersheds are necessary. This study provides a holistic view of the forest watershed by investigating fluvial geomorphological descriptions, land use land cover changes, Sediment parameter for better management of watershed. These factors were significantly influencing the watershed's capacity to store water, runoff, infiltration capacity, peak flow, susceptibility to erosion and landslides, etc. Morphometric analysis, Hypsometric analysis, Random Forest Algorithm, Composite Intensity Mapping Unit, Principal Component Analysis methods were utilized for the computation, extraction of watershed parameters to construct Compound parameter as a basis for watershed ranking. In this case of investigation, The Kundha River Sub-watershed with 160 km² of catchment area of Upper Bhavani River Basin in Tamil Nadu, South India was investigated. It has 14 sub-watersheds (KSW1-KSW14) with elevation variation about 1618 to 2623 m above Mean Sea Level. The KSW14 &amp; KSW11 are more vulnerable to soil erosion due to high basin relief. The Kundha Sub-watershed is characterized by features such as 47 % of the total area having steep slopes, 50 % of the total area belonging to the Hydrologic Soil Group (HSG) A, an 11 % reduction in the vegetation class over a five-year period, and a very high Sediment Yield Index value. The much-influenced parameters viz., vegetation class, stream frequency, drainage density and Sediment Yield Index were detected and there are strongly recommended for the prioritization of any identical forest watersheds. According to the investigation, the area of 10.09 km² including KSW11 required instantaneous implementation of catchment area treatment measures to conserve natural resources and to ensure the water security.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109561"},"PeriodicalIF":3.1,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstructing bed topography of a shallow river from close-range aerial imagery: Multi-UAV experimental campaign in the Izera river (SW Poland/N Czechia)","authors":"Matylda Witek ,&nbsp;Grzegorz Walusiak ,&nbsp;Michał Halicki ,&nbsp;Joanna Remisz ,&nbsp;Dorota Borowicz ,&nbsp;Krzysztof Parzóch ,&nbsp;Łukasz Kasprzak ,&nbsp;Jakub Langhammer ,&nbsp;Michal Gallay ,&nbsp;Jakub Miřijovský ,&nbsp;Jan Šašak ,&nbsp;Jan Kaňuk ,&nbsp;Theodora Lendzioch ,&nbsp;Robert Minařík ,&nbsp;Stanislav Popelka ,&nbsp;Tomasz Niedzielski","doi":"10.1016/j.geomorph.2024.109544","DOIUrl":"10.1016/j.geomorph.2024.109544","url":null,"abstract":"<div><div>The objective of the study is to reconstruct the bathymetry of a shallow river using the Structure-from-Motion algorithm and to evaluate the robustness of the approach by exploring its repeatability and reproducibility. To address this issue, the multi-UAV experimental campaign was organized in SW Poland/N Czechia, and focused on the smoothly flowing Izera river. Unmanned aerial vehicles used to conduct the experiment were: one fixed-wing aircraft (eBee by SenseFly) and three multi-rotor aircrafts (DJI Matrice 210-RTK V2, DJI Mavic 2 Pro, DJI Phantom 4 Pro). Riverbed topography was reconstructed 48 times (2 sites × 4 platforms × 3 resolutions × 2 repetitions) using Structure-from-Motion algorithm, corrected for refraction. The reference elevations of riverbed were obtained using leveling, while water surface elevations were determined by a terrestrial laser scanner. Root mean square errors (RMSE) of the reconstructions of river bottom topography (mostly underestimated) varied between 2.6 cm and 109.3 cm, with the median of 17.5 cm. The error of reconstruction of river bottom topography falls within a typical error range known for through-water photogrammetry. RMSE of the repeatability test for all platforms is smaller than 10 cm in 57 % (up to 76 % for only multi-rotor aircrafts) of the cases and for the reproducibility test in 47 % (up to 60 % for only multi-rotor aircrafts) of the cases. Hence, it was found that the studied approach is robust in terms of its repeatability and reproducibility, predominantly when multi-rotor aircrafts are utilized. The effectiveness of the bottom reconstruction, however, depends on the channel morphology, and specifically decreases at the vicinity of the river banks.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109544"},"PeriodicalIF":3.1,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revised wind-driven sand transport model based on turbulent kinetic energy","authors":"Yuxin Liu ,&nbsp;Xin Gao ,&nbsp;Yongcheng Zhao ,&nbsp;Hongjing Ren ,&nbsp;Jiaqiang Lei","doi":"10.1016/j.geomorph.2024.109562","DOIUrl":"10.1016/j.geomorph.2024.109562","url":null,"abstract":"<div><div>Wind is the primary driving factor of sand transport and shapes diverse landscapes. Owing to the inherent intermittency and pulsation of winds, existing models cannot accurately predict sand fluxes as a function of winds. When wind speed is below the fluid threshold, turbulent kinetic energy dominates sand transport, preventing accurate predictions of sand flux. This study proposes a term derived from wind turbulent kinetic energy to revise the classical wind-blown sand transport models. We combined both low- and high-frequency field measurements of wind in the revised model and found that the new model not only overcomes the inaccuracies in predicting sand fluxes caused by low-frequency winds but also avoids the flux uncertainties associated with excessive turbulent pulsation caused by high-frequency winds. This newly developed model reduced biases in sand flux predictions under low-frequency wind speeds. Furthermore, in terms of turbulent pulsation, the optimal wind sampling frequency for accurately predicting sand fluxes over long timescales was also determined. However, the current model proposed the initial assumptions and local validation, and its applicability requires more validation.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109562"},"PeriodicalIF":3.1,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study of sand splash-saltation process in different moisture","authors":"Zhenghu Ge ,&nbsp;Chao Zhang ,&nbsp;Hongchao Dun ,&nbsp;Ning Huang","doi":"10.1016/j.geomorph.2024.109553","DOIUrl":"10.1016/j.geomorph.2024.109553","url":null,"abstract":"<div><div>Moisture significantly influences the splash-saltation process of sand, which is a pivotal mechanism in aeolian sand transport and the evolution of dunes. Although the impact of soil moisture on the principles governing the wind-driven initiation of sand lift-off has been thoroughly explored, its contribution to sand impact incipience formed by sand-bed collision can be substantial. In fact, the absence of soil moisture mechanism in splash-saltation limits the calculation accuracy and prediction ability of the aeolian sand transport model in wet areas. In this work, we present an experimental setup to study the law of sand movement in the splash-saltation process with different moisture using the high-speed digital camera and sand particle launcher. The results reveal that the restitution coefficient, ejection speed and number of liftoff particles follow a lognormal distribution. The restitution coefficients of rebounding sand grains first increase and then decrease with the increase of surface moisture content. The multi particle liquid-bridge system around the collision point significantly reduces the number of splashed sand particles on the one hand, and on the other hand, concentrates the energy more on the splashed sand particles and thus increases their speeds. This study enhances the understanding of wind-sand movement within the context of global warming. The insights derived from our research have the potential to improve the accuracy of wind-sand transport modeling and forecasting.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109553"},"PeriodicalIF":3.1,"publicationDate":"2024-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deciphering the grain size fining and provenance variation of lower Yellow River fluvial sediments in light of Holocene climatic changes and anthropogenic influences","authors":"Qinmian Xu ,&nbsp;Shuangwen Yi ,&nbsp;Zhibin Xiao ,&nbsp;Xiaodong Miao ,&nbsp;Shi-Yong Yu ,&nbsp;Junsheng Nie ,&nbsp;Huayu Lu","doi":"10.1016/j.geomorph.2024.109552","DOIUrl":"10.1016/j.geomorph.2024.109552","url":null,"abstract":"<div><div>The dynamics of fluvial processes in the lower Yellow River during the warm Early and Middle Holocene can serve as an analogue for future global warming, thus providing a scientific basis for addressing contemporary river issues. However, the Early and Middle Holocene riverbed sediments in the lower Yellow River have rarely been investigated. Here, we conducted detrital zircon U<img>Pb dating and grain-size analysis of four riverbed samples with different ages collected via four boreholes across the North China Plain. Our results revealed that during the Early Holocene, coarse-grained sediments derived from upstream mountains were widely present as a result of gradually increasing precipitation. During the Middle Holocene, riverbed sediments gradually became finer due to the increased input of fine-grained sediments from the Chinese Loess Plateau following the northward shift of the rain belt. During the Late Holocene, riverbed sands continued the fining trend because of reduced stream flow, which limited the transport of coarse-grained sediments into the lower reaches. Continuous enhanced anthropogenic influences resulted in more fine-grained sediments in the riverbed. We conclude that millennial-scale precipitation variation controlled the flow discharge and sediment composition in the lower Yellow River during the Holocene. Our findings suggest that increasing flow discharge through water regulation can effectively address current challenges and help adapt to future global warming.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109552"},"PeriodicalIF":3.1,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}