On September 14, 2019, a reactivated landslide with a volume of 1.3 × 10
7
m
3
occurred in Changhe Town, Tongwei County, Gansu Province, China. As a result, a provincial highway, brickfield, and ...bridge were destroyed. Based on field investigation, interferometric synthetic aperture radar (InSAR) as well as unmanned aerial vehicle (UAV) photogrammetry, high-resolution remote sensing imagery, and digital elevation model, we addressed the surface displacement, travel distance, topographic changes, and causative factors of the Changhe landslide. The result shows the combination of ascending and descending orbit datasets can not only be used to monitor the landslide surface displacement but also to verify the deformation results. This landslide is a typical retrogressive landslide where large pre-failure deformation exists in the lower part of the landslide body. We detected the surface travel distance of the landslide and found spatial differences exist in the surface travel distance of the landslide. The deposit volume slightly exceeds erosion volume due to decompaction during the landslide. The frequency distribution of the basic topographic factors before and after the landslide is different, which indicates that the landslide event significantly changed the local topography and geomorphology. This study provides an insight into the spatiotemporal evolution of the landslide and has practical importance for early warning of landslides and risk mitigation.
High-strength steel suffers from an increasing susceptibility to solidification cracking in welding due to increasing carbon equivalents. However, the cracking mechanism is not fully clear for a ...confidently completely crack-free welding process. To present a full, direct knowledge of fracture behavior in high-strength steel welding, a three-dimensional (3-D) modeling method is developed using the extended finite element method (XFEM). The XFEM model and fracture loads are linked with the full model and the output of the thermo-mechanical finite element method (TM-FEM), respectively. Solidification cracks in welds are predicted to initiate at the upper tip at the current cross-section, propagate upward to and then through the upper weld surface, thereby propagating the lower crack tip down to the bottom until the final failure. This behavior indicates that solidification cracking is preferred on the upper weld surface, which has higher weld stress introduced by thermal contraction and solidification shrinkage. The modeling results show good agreement with the solidification crack fractography and in situ observations. Further XFEM results show that the initial defects that exhibit higher susceptibility to solidification cracking are those that are vertical to the weld plate plane, open to the current cross-section and concentratedly distributed compared to tilted, closed and dispersedly distributed ones, respectively.
Information about the long-term spatiotemporal evolution of landslides can improve our understanding of the landslide development process and can help prevent landslide disasters. However, few ...studies have been devoted to the pre- and post-failure spatiotemporal evolution process and pattern of landslides. Therefore, we studied the pre- and post-failure geomorphic changes and spatiotemporal evolution of the 2019 Jiangou landslide based on field investigations, interferometric synthetic aperture radar (InSAR), unmanned aerial vehicle (UAV) observations, and remote sensing techniques. The results show that the volume of the deposition of the Jiangou landslide is less than the depletion volume, which means the remaining landslide materials were washed away when the dammed lake collapsed. Moreover, the InSAR technique has an advantage in terms of the retrieval of pre- and post-failure creep deformation. Our analysis suggests that the Jiangou landslide has experienced long-term creep. Potential landslide risks still exist after the previous failure event. Furthermore, we found that the pre- and post-failure spatiotemporal deformation processes and evolutionary patterns of the landslide are different. The pre-failure evolutionary pattern of the landslide is a progressive failure mode, while the post-failure evolutionary pattern is a retrogressive failure mode. This evolution provides a reference for local governments to further monitor or take effective prevention measures against future landslide failures.
Copy number variants (CNVs) are suggested to have a widespread impact on the human genome and phenotypes. To understand the role of CNVs across human diseases, we examine the CNV genomic landscape of ...100,028 unrelated individuals of European ancestry, using SNP and CGH array datasets. We observe an average CNV burden of ~650 kb, identifying a total of 11,314 deletion, 5625 duplication, and 2746 homozygous deletion CNV regions (CNVRs). In all, 13.7% are unreported, 58.6% overlap with at least one gene, and 32.8% interrupt coding exons. These CNVRs are significantly more likely to overlap OMIM genes (2.94-fold), GWAS loci (1.52-fold), and non-coding RNAs (1.44-fold), compared with random distribution (P < 1 × 10
). We uncover CNV associations with four major disease categories, including autoimmune, cardio-metabolic, oncologic, and neurological/psychiatric diseases, and identify several drug-repurposing opportunities. Our results demonstrate robust frequency definition for large-scale rare variant association studies, identify CNVs associated with major disease categories, and illustrate the pleiotropic impact of CNVs in human disease.
The aeolian loess-paleosol sections on the northeast Tibetan Plateau (NETP) are a valuable source of paleoclimatic information because of their geographical location. In this study, two late ...Pleistocene–Holocene aeolian loess-paleosol sections were identified based on detailed field investigations in the Maqu reach in the Yellow River source area on the NETP. A robust chronostratigraphic framework for these two sections was established using AMS 14C dating, optically stimulated luminescence (OSL) dating, Bacon age-depth modelling and stratigraphic correlation. Measurements of magnetic susceptibility, hygroscopic water, loss-on-ignition, grain-size, micromorphology, and chemical element analysis suggest that most stratigraphic units in these aeolian loess-paleosol sections are in weak weathering and pedogenesis, whereas the mid-Holocene paleosol approaches to the moderate weathering and pedogenesis, and the sediments are in initial weathering stage of Na+ and Ca2+ leaching is dominated by plagioclase weathering. The main pedogenesis in the mid-Holocene paleosol is calcification process. In terms of intensity of weathering and pedogenesis, the stratigraphic units can be ordered as follows: paleosol > modern soil > transitional loess > aeolian loess. Multi-index comparison shows that the local climatic evolution during the late Pleistocene–Holocene was closely related to the evolution of the East Asian summer monsoon (EASM) and the Westerlies. Overall, the results provide a foundation for further exploration of the pedogenic and paleoclimatic evolution on the NETP.
•Chronostratigraphic framework for two aeolian loess-paleosol sections is established.•Sediments are at initial stage of Na+ and Ca2+ leaching.•Pedogenesis in the mid-Holocene paleosol is calcification process.•Pedogenic intensity is paleosol > modern soil > transitional soil > aeolian loess.
•Two aeolian loess-paleosol sections have a basal age of 14000–11500 yr BP.•Four stages of paleoclimate evolution have been identified since the last deglaciation.•Westerlies and the Tibetan Plateau ...Monsoon dominate dust transport.
Two late Pleistocene-Holocene aeolian loess-paleosol sections were identified in the Yellow River source area on the northeast (NE) Tibetan Plateau. Based on the comprehensive study on multiple proxies, AMS 14C and optically stimulated luminescence (OSL) dates, these two sections have a basal age of 14000–11500 yr BP, suggesting that they accumulated since the last deglaciation. Four stages of paleoclimate evolution can be summarized as follows. (1) A cold-dry period was dominated by the Westerlies in the late Pleistocene (ca. 14000–11500 yr BP). (2) A gradual transition to warm-wet with the weakened Westerlies and strengthened East Asian summer monsoon (EASM) occurredin the early Holocene (ca. 11500–9000 yr BP). (3) A warm-wet episode was under strong EASM in the middle Holocene (ca. 9000–3100 yr BP), however, a cold event was identified at 5000–3500 yr BP, which was caused by the abrupt weakening of the EASM and the strengthening of the Westerlies. (4) A phase of gradually shifting to dry-cold was controlled by the weakened EASM and strengthened Westerlies (after ca. 3100 yr BP). The assemblage of grain-size end-member modelling analysis (EM1-EM5) and heavy minerals indicated that aeolian deposit units have multiple sediment provenances and transport processes. EM1 is clay deposits composed of secondary clay minerals produced during weathering and pedogenesis, whereas EM2 is fine silts derived from distant dust transported through long-existing high-level Westerlies. EM3 and EM4 are coarse silts that originated from the moraines and periglacial deposits in the middle and distant source areas transported by the Westerlies and Tibetan Plateau Monsoon. Lastly, EM5 is sand from fluvial deposits and slope clastics transported by strong valley wind within the local area. This study is helpful to understand the mechanisms of paleoclimate evolution on the NE Tibetan Plateau. It also has important implications for characterizing and subdividing aeolian loess in China.
Diabetes impacts approximately 200 million people worldwide, of whom approximately 10% are affected by type 1 diabetes (T1D). The application of genome-wide association studies (GWAS) has robustly ...revealed dozens of genetic contributors to the pathogenesis of T1D, with the most recent meta-analysis identifying in excess of 40 loci. To identify additional genetic loci for T1D susceptibility, we examined associations in the largest meta-analysis to date between the disease and ∼2.54 million SNPs in a combined cohort of 9,934 cases and 16,956 controls. Targeted follow-up of 53 SNPs in 1,120 affected trios uncovered three new loci associated with T1D that reached genome-wide significance. The most significantly associated SNP (rs539514, P = 5.66×10⁻¹¹) resides in an intronic region of the LMO7 (LIM domain only 7) gene on 13q22. The second most significantly associated SNP (rs478222, P = 3.50×10⁻⁹ resides in an intronic region of the EFR3B (protein EFR3 homolog B) gene on 2p23; however, the region of linkage disequilibrium is approximately 800 kb and harbors additional multiple genes, including NCOA1, C2orf79, CENPO, ADCY3, DNAJC27, POMC, and DNMT3A. The third most significantly associated SNP (rs924043, P = 8.06×10⁻⁹ lies in an intergenic region on 6q27, where the region of association is approximately 900 kb and harbors multiple genes including WDR27, C6orf120, PHF10, TCTE3, C6orf208, LOC154449, DLL1, FAM120B, PSMB1, TBP, and PCD2. These latest associated regions add to the growing repertoire of gene networks predisposing to T1D.
Rainfall-induced shallow landslides are widespread throughout the world, and vegetation is frequently utilized to control them. However, in recent years, shallow landslides have continued to ...frequently occur during the rainy season on the vegetated slopes of the Loess Plateau in China. To better probe this phenomenon, we considered vegetation cover in the sensitivity analysis of landslide hazards and used the transient rainfall infiltration and grid-based regional slope stability (TRIGRS) model to quantitatively describe the impacts of different types of vegetation cover on slope stability. Based on the rainfall information for landslide events, the spatiotemporal distributions of the pore water pressure and the factor of safety of the vegetated slopes were inverted under the driving changes in the soil properties under different vegetation types, and the average prediction accuracy reached 79.88%. It was found that there was a strong positive correlation between the cumulative precipitation and the proportion of landslide-prone areas in woodland covered by tall trees, grassland covered by shrubs and grasses, and cultivated land. The highest landslide susceptibility, which has the greatest potential to hasten the occurrence of rainfall-induced landslides, is found in woodland with tall trees. Therefore, this paper proposes the promoting relationship between vegetation and landslide erosion, which provides a new scientific perspective on watershed management to prevent shallow landslide disasters and manage and develop watershed vegetation.
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