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Subaqueous deltas are facing growing threats of erosion. Tropical cyclones (TCs), which are predicted to affect mid‐latitude estuaries more frequently with higher intensity in the future, can play an important role in subaqueous delta geomorphology change. Nevertheless, direct in situ measurement of TC‐induced bed elevation change (BEC) was rarely reported before. In this study, four tripods were deployed at different parts of the Changjiang River subaqueous delta (CRSD) to capture BEC during TCs in July 2019. Rapid erosion (20 mm day−1) during TC Danas (2019) was observed by high precision bed elevation measurement, over 10 times faster than that during calm weather conditions. Moreover, the recorded rates of BEC varied substantially among these stations. A coupled three‐dimensional wave‐current‐sediment model was then developed for the CRSD to help understand the spatial variability of observed BEC. The model results showed two striking features of BEC during TC Danas: (a) enhanced sediment accretion near the sharp bottom salinity front offshore of the north channel; (b) marked erosion near the front of CRSD. Further analysis showed that the converging bottom currents in concert with enhanced sediment resuspension during TC Danas led to significant convergence of sediment flux near the bottom salinity front. In addition, the diverging isobaths along the front of the CRSD resulted in the onshore deviation of bottom current and diverging sediment flux under the downwelling‐favorable winds of Danas. Many TCs in the CRSD generate similar downwelling‐favorable winds and currents, growing TC threats in the future may therefore exacerbate erosion in this region. Plain Language Summary: Submerged river deltas are vulnerable to erosion, and this problem may worsen due to the increased frequency and intensity of tropical cyclones (TCs) in the future. However, the impact of TCs on delta erosion is not fully clear. To address this issue, this study deployed four tripods in different parts of the Changjiang River submerged delta during TC Danas (2019). The observed data showed that erosion occurred much faster during the storm than during calm weather. Interestingly, the erosion rate was different at each tripod. A computer model was built to help understand why the erosion rate varied in space. Model results showed that sediment built up in the region where fresh water meets seawater (known as front), since the front can act as a barrier to the seaward movement of sediment brought by the river. In contrast, strong erosion occurred at the offshore edge of the delta. This is caused by diverging ocean currents along widened submerged delta driven by north winds, which carried sediments away from this region. Computer simulations of more storm events confirmed that such erosion can frequently occur at the same location during TCs. This highlights the importance of protecting these areas in the future. Key Points: Fast erosion near the 30 m isobath of the Changjiang River subaqueous delta (CRSD) was captured by in situ measurement during Cyclone DanasConverging flows near the bottom salinity front led to continuous deposition around the 10 m isobath of the CRSDDiverging isobaths facilitate the erosion of subaqueous delta during downwelling‐favorable storm winds [ABSTRACT FROM AUTHOR]

Many of the world's mega‐river deltas are currently degrading due to a shortage of sediment supply feeding their construction. Here, using bathymetric and seismic data, the geomorphological/sedimentary evolution on and near a recently abandoned (1976 CE) Huanghe delta lobe is investigated. The delta front (DF) exhibits a lobe switching‐controlled pattern of progradation followed by mass wasting on the upper front, and redeposition at the seaward toe of the front; the latter process appears to be associated with sediment failure and contributes to delta degradation. During degradation, mass wasting‐driven deepening of the upper DF was initially up to ∼0.86 m/yr from 1978 to 1985 CE, slowed to ∼0.12 m/yr from 1985 to 2000 CE, and has been negligible since. In either prograding or degrading, gravity‐driven sedimentation results in a downlapping seismic unit superimposed on the bottomset of an earlier converging clinoform, with numerous buried/exposed submarine channels at its seaward terminus. These units exhibit a shore‐parallel elongated and continuous geometry, suggesting lateral spreading, which we attribute to alongshore hydrodynamic (especially tidal) remolding. Our findings underscore the significance of sediment gravity flows in the evolution of a degrading delta front, particularly as a principal mechanism of downslope mass transport that gentled (halving the gradient) and reshaped the DF over time. Gravity‐driven accumulations sourced from upper DF collapse can account for ∼1/3 of the previous DF and laterally extend over an unexpectedly large area (∼60‐km long) through hydrodynamic redistribution. Both processes should be considered for modeling other subaqueous deltas. Plain Language Summary: At underwater river deltas, gravity can cause sediment to flow downhill, which alters geological, chemical and biological processes and poses hazards to human infrastructures. Due to changes in the river on land, delta lobes can switch from one part of the coast to another, which alters the conditions that cause gravity flows. Our understanding of how the gravity flows respond to channel switching is very limited. This paper reports on seven repeated bathymetric surveys and a seismic survey collected at a recently abandoned Huanghe (Yellow River) delta lobe over four decades. We found that the gravity flows take place both when the delta lobe is active and after abandonment. Gravity flows make the underwater delta slope gentler by taking away sediment from the upper slope and moving it to the lower slope. This happened rapidly within the first decade after abandonment and slowed down thereafter. The redeposited sediments were spread out parallel to the shoreline by ocean currents. Our study highlights the significance of gravity flows in reshaping the underwater delta slope after abandonment, which may provide implications for enabling better societal response to the global deltaic degradation caused by reductions in river sediments transported to oceans. Key Points: Sediment gravity flows reshape and gentle the abandoned delta front (DF) slope over timeGravity flows dominated delta degradation via mass wasting on the upper DF and accumulating on the lower frontGravity‐driven sedimentation laterally spread over decadal span likely due to hydrodynamic redistribution [ABSTRACT FROM AUTHOR]

Frequency changes in intense typhoons are of great concern to modern society. However, current understanding of the influence of climate on typhoon activity on the millennial scale is restricted by the sparseness of pre‐observational reconstructions in the north‐western Pacific. This study presents a 5500 year long typhoon record from the Jiangsu coast that provides the first >2 ka record in eastern China. Variations in the D90 grain size are the best predictor of recent typhoons in a second short high‐resolution core. Comparison with other typhoon records from south‐eastern China establishes a China millennial typhoon variability index during the middle to late Holocene, with maxima at ca 4750 ± 170, 3500 ± 220, 1500 ± 480 and 250 ± 170 yr bp and minima at ca 5200 ± 300, 4150 ± 430, 2600 ± 650 and 750 ± 270 yr bp. Peaks in typhoon activity in south‐eastern China (compared with Japan) correlate with damped (enhanced) El Niño–Southern Oscillation and weak (strong) East Asian Summer Monsoon, indicating a seesaw pattern in typhoon activity between the two regions. A shift in typhoon frequency pattern was also identified around 2000 yr bp in south‐eastern China, with subsequent more frequent typhoon activity. At that time there was sustained Atlantic Meridional Overturning Circulation reduction and its associated El Niño–Southern Oscillation enhancement, so Atlantic Meridional Overturning Circulation‐driven El Niño–Southern Oscillation changes are likely to be the major cause of the significant increase in typhoon activity since 2000 yr bp, resulting in the 1500 ± 480 and 250 ± 170 yr bp China millennial typhoon variability peaks. To accurately predict changes in intense typhoon activity, it is therefore important to understand how the Atlantic Meridional Overturning Circulation and El Niño–Southern Oscillation will respond to future climate change. [ABSTRACT FROM AUTHOR]

Facing considerable challenges associated with aging and dementia, China urgently needs an evidence‐based health‐care system for prevention and management of dementia. The Beijing Aging Brain Rejuvenation Initiative (BABRI) is a community‐based cohort study initiated in 2008 that focuses on asymptomatic stages of dementia, aims to develop community‐based prevention strategies for cognitive impairment, and provides a platform for scientific research and clinical trials. Thus far, BABRI has recruited 10,255 participants (aged 50 and over, 60.3% female), 2021 of whom have been followed up at least once at a 2‐ or 3‐year interval. This article presents aims and study design of BABRI; summarizes preliminary behavioral and neuroimaging findings on mild cognitive impairment (MCI) and results of clinical trials on MCI; and discusses issues concerning early prevention in community, MCI diagnosis methods, and applications of database of aging and dementia. BABRI is proposed to build a systematic framework on brain health in old age. [ABSTRACT FROM AUTHOR]

Coastal deltaic deposits are the primary locations for sediment storage on Earth, and quantifying their source contributions is a critical prerequisite for delineating S2S patterns in marginal seas. In most cases, quantification for the contribution by fine‐grained sediments (i.e. particle size < 63 μm) is considered to be representative to constrain the overall sediment supply. However, this approach may be inappropriate because large differences exist between the two quantities. Here we propose an approach to solve the problem, which is based on the maximum number of tracers from multiple sediment size fractions incorporating the content of all size fractions of sediment. Using this approach, absolute source contributions during the Holocene are reconstructed that provide a first‐order model for the S2S pattern of the central Jiangsu coast, China. The Huanghe River is the strongest driver for the Holocene sedimentation, with a mean contribution of ~72 ± 6% (1417 × 108 t). The absolute contributions from the Changjiang and offshore areas were of secondary importance, (i.e. ~17 ± 1% (330 × 108 t) and ~11 ± 5% (217 × 108 t), respectively). The results show that a large difference between the relative and absolute source contributions and the assumption that the relative contribution represents the absolute contribution is invalid in a coastal setting. The impact of the Huanghe is mainly based on episodic events, such as the event of 1128–1855 AD. The model also reveals that the offshore sediments are as important as the Changjiang sediments for the central Jiangsu coast during the Holocene. Thus, the model provides both the time series and overall quantities of sediment supply during the formation and evolution of the Holocene tidal flats on the Jiangsu coast. Our findings shed new light on quantitative analysis of sediment sources applicable to future S2S studies of marginal seas. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Cognitive impairment of cerebral small vessel disease (CSVD) is one of the most common cognitive disorders. It has a high incidence and results in heavy social burden; thus, it is essential to provide reasonable diagnosis and treatment in clinical practice. Based on the results of clinical research and related reports, combined with the actual situation in China, we propose a diagnosis and treatment guideline for cognitive impairment of CSVD. [ABSTRACT FROM AUTHOR]