Subseasonal to seasonal Arctic sea-ice prediction:A grand challenge of climate science

On 15 September 2020,the Arctic sea-ice extent(SIE)reached its annual minimum,which,based on data from the National Snow and Ice Data Center(NSIDC,2020a),was about 3.74 million km^(2)(1.44 million square miles).This value was about 40%less than the climate average(~6.27 million km^(2))during 1980–2010.It was second only to the record low(3.34 million km^(2))set on 16 September 2012,but significantly smaller than the previous second-lowest(4.145 million km^(2),set on 7 September 2016)and third-lowest(4.147 million km^(2),set on 14 September 2007)values,making 2020 the second-lowest SIE year of the satellite era(42 years of data).

Experimental Investigation on Fracture Performance of Short Basalt Fiber Bundle Reinforced Concrete

In this paper,a notched three-point bending test is used to study the fracture performance of the short basalt fiber bundle reinforced concrete(SBFBRC).To compare and analyze the enhancement effect of different diameters and different content of basalt fiber bundles on the fracture performance of concrete,some groups are set up,and the P-CMOD curves of each group of specimens are measured,and the fracture toughness and fracture energy of each control group are calculated.The fracture toughness and fracture energy are two important fracture performance parameters to study the effect and law of the new basalt fiber bundles on the fracture performance of concrete.The research results show that the diameter and content of the new basalt fiber bundles have a certain effect on the fracture performance of concrete.With the increase of the content of basalt fiber bundles,the peak load,crack initiation toughness,instability toughness and fracture energy of SBFBRC are greatly improved compared with the benchmark group.When the fiber bundle diameter is 0.2 mm,the peak load increases by 69.5%compared with the reference group.The instability toughness reaches its maximum value at 0.2 mm diameter,which is 59.7%higher than the benchmark.

Atmospheric Rivers and Mei-yu Rainfall in China:A Case Study of Summer 2020

Atmospheric rivers(ARs)are long,narrow,and transient filaments of strong horizontal water vapor transport that can lead to extreme precipitation.To investigate the relationship between ARs and mei-yu rainfall in China,the mei-yu season of 2020 in the Yangtze-Huaihe River basin is taken as an example.An adjusted AR-detection algorithm is applied on integrated water vapor transport(IVT)of the ERA5 reanalysis.The JRA-55 reanalysis and the data from Integrated Multi-satellite Retrievals for GPM(IMERG)are also utilized to study the impacts of ARs on mei-yu rainfall in 2020.The results reveal that ARs in East Asia have an average length of 5400 km,a width of 600 km,a length/width ratio of 9.3,and a northeastward orientation of 30°.ARs are modulated by the western North Pacific subtropical high.The IVT core is located at the south side of low pressure systems,moving eastward with a speed of 10°d−1.For the cross sections of ARs in the Yangtze-Huaihe River basin,75%of the total flux is concentrated below 4 km with low-level jets near AR cores.Moreover,ARs occur mainly in the mei-yu period with a frequency of 20%–60%.The intensity of AR-related precipitation is 6–12 times that of AR-unrelated precipitation,and AR-related precipitation contributes about 50%–80%to total mei-yu precipitation.As shown in this case study of summer 2020,ARs are an essential part of the mei-yu system and have great impacts on mei-yu rainfall.Thus,ARs should receive more attention in research and weather forecast practices.

Tissue plasminogen activator-independent roles of neuroserpin in the central nervous system

A number of studies have confirmed the existence of tissue-type plasminogen activator-independent roles of neuroserpin, a member of the serine protease inhibitor superfamily. In this review article, we aim to clarify this role. These unique roles of neuroserpin are involved in its neuroprotective effect during ischemic brain injury, its regulation of tumorigenesis, and the mediation of emotion and cognition through the inhibition of urokinase-type plasminogen activator and fibrinolysin, modification of Th cells, reducing plaque formation, promoting process growth and intracellular adhesion, and alterina the expression of cadherin and nuclear factor kaooa B.

Adult-born neurons in critical period maintain hippocampal seizures via local aberrant excitatory circuits

Temporal lobe epilepsy(TLE),one common type of medically refractory epilepsy,is accompanied with altered adult-born dentate granule cells(abDGCs).However,the causal role of abDGCs in recurrent seizures of TLE is not fully understood.Here,taking advantage of optogenetic and chemogenetic tools to selectively manipulate abDGCs in a reversible manner.

Neogene integrative stratigraphy,biotas,and paleogeographical evolution of the Qinghai-Tibetan Plateau and its surrounding areas

The remarkable uplift of the Tibetan Plateau in the Neogene had great impacts on the climate and environment of East Asia and even the world.Therefore,establishment of the Neogene stratigraphic framework of the Tibetan Plateau is of great significance to research in various fields of geosciences.Based on marine sediments,the international chronostratigraphic system of the Neogene is divided into six stages in the Miocene and two stages in the Pliocene.Since the beginning of the Cenozoic,the share of terrestrial strata on continents has increased rapidly.By the Neogene,it had far exceeded that of marine strata,and almost all deposits on the Tibetan Plateau and its surrounding areas were terrestrial strata.In China,the Miocene includes five stages and the Pliocene includes two stages.Except for the Tunggurian of the Miocene,which has a lower boundary at 15 Ma,the other stages have the same paleomagnetic definitions and time intervals as the corresponding international marine stages.Mammalian fossils play a very important role in the division and correlation of Cenozoic terrestrial strata,and rodent,carnivore,proboscidean,perissodactyl and artiodactyl fossils are especially important in Neogene terrestrial biostratigraphy.There are many basins with well-exposed strata and abundant mammalian fossils in the Tibetan Plateau.The lower boundary stratotype sections of the Neogene Xiejian and Bahean stages are located respectively in the Xining and Linxia basins,and there are precise paleomagnetic dates in coordination with mammalian fossils.The lower boundary stratotypes of other stages can also be effectively determined in the Tibetan Plateau.Many first appearing mammalian genera in East Asia also appeared in the Tibetan Plateau and its surrounding areas,especially in the Linxia Basin on the northeast margin and in the Siwaliks on the southwest margin.Among them,Prodeinotherium first appeared at the bottom of the Miocene in the Siwaliks,and the earliest Hipparion of the Old World first appeared at the bottom of the Bahean Stage in the Linxia Basin.Carbon and oxygen isotope analysis of enamel and paleosols of Cenozoic sediments and mammal fossils in the Tibetan Plateau and its surrounding areas have been used to reconstruct the climate,environment and vegetation development characteristics,and revealed that these changes were not only related to global change,but also had regional features.Evidence of the Late Miocene C4plant expansion event based on carbon isotope changes comes from the southern margin of the Tibetan Plateau,but in sharp contrast,δ13C indicates that there was still no clear or significant C4plant signal on the northern margin of the Tibetan Plateau until the end of the Neogene.Theδ18O analysis shows that there were several major climate change events in the Cenozoic,especially in the Late Miocene at about 7 Ma,when positive drift ofδ18O indicates that the northern and southern sides of the Tibetan Plateau were changing to drier environments.The strong uplift of the Tibetan Plateau in the Late Miocene strengthened the thermal contrast between sea and land,which strengthened monsoon circulation and led to the expansion of C4vegetation in South Asia.However,the East Asian summer monsoon,which can bring atmospheric precipitation and a climate suitable for C4plants to northern China,was not enough to affect the northern Tibetan Plateau.The Tibetan Plateau on the whole rose to an altitude of about 3000 m in the Miocene,becoming a barrier to mammalian migration;it reached its modern altitude of more than 4000 m in the Pliocene,thus forming a cryosphere environment,which led to the emergence of ancestral types of the Ice Age fauna.

Porphyrin-based framework materials for energy conversion

With the increasing demand for fuel causing serious environmental pollution,it is urgent to develop new and environmentally friendly energy conversion devices.These energy conversion devices,however,require good,inexpensive materials for electrodes and so on.The multifunctional properties of porphyrins enable framework materials(e.g.,metal-organic frameworks and covalent organic frameworks)to be applied in energy conversion devices due to their simple synthesis,high chemical stability,abundant metallic active sites,adjustable crystalline structure and high specific surface area.Herein,the types of porphyrin structural blocks are briefly reviewed.They can be used as organic ligands or directly assembled with framework materials to generate high-performance electro-/photo-catalysts.These types of catalysts applied in electro-/photo-catalytic water splitting,electro-/photo-catalytic carbon dioxide reduction,and electrocatalytic oxygen reduction are also summarized and introduced.At the end of the article,we present the challenges of porphyrin-based framework materials in the above application and corresponding solutions.We expect porphyrin-based framework materials to flourish energy conversion in the coming years.

Microglial Depletion does not Afect the Laterality of Mechanical Allodynia in Mice

Mechanical allodynia(MA),including punctate and dynamic forms,is a common and debilitating symptom suffered by millions of chronic pain patients.Some peripheral injuries result in the development of bilateral MA,while most injuries usually led to unilateral MA.To date,the control of such laterality remains poorly understood.Here,to study the role of microglia in the control of MA laterality,we used genetic strategies to deplete microglia and tested both dynamic and punctate forms of MA in mice.Surprisingly,the depletion of central microglia did not prevent the induction of bilateral dynamic and punctate MA.Moreover,in dorsal root ganglion-dorsal root-sagittal spinal cord slice preparations we recorded the low-threshold Aβ-fiber stimulation-evoked inputs and outputs of superficial dorsal horn neurons.Consistent with behavioral results,microglial depletion did not prevent the opening of bilateral gates for Aβpathways in the superficial dorsal horn.This study challenges the role of microglia in the control of MA laterality in mice.Future studies are needed to further understand whether the role of microglia in the control of MA laterality is etiology-or species-specific.

Applications of metal nanoparticles/metal-organic frameworks composites in sensing field

Metal nanoparticles(MNPs) possess size-dependent desirable electronic and optical properties while metal-organic frameworks(MOFs) have an edge over extremely large specific surface areas, homogeneous structure, high porosity and remarkable chemical stability. Their combination(MNPs/MOFs) is a novel nanomaterial with broad application prospect in sensing field. To improve performance in sensing applications, we have paid great attention to synergistic effects between the two compositions above. Because of the synergistic effects between MNPs and MOFs, sensors on the basis of MNPs/MOFs composites show significant sensing enhancement with respect to stability, selectivity and sensitivity. In this review, various applications for MNPs/MOFs composites in electrochemical sensing, fluorescent sensing, colorimetric sensing, surface-enhanced Raman scattering sensing and chemiluminescence/electrochemiluminescence sensing are focused and summarized. Besides, the synergistic interactions between MNPs and MOFs was investigated. Finally, based on theoretical information from the reports as well as experimental experience, this review offers the challenges and opportunities for future research on MNPs/MOFs composites.

Correction:Microglial Depletion does not Affect the Laterality of Mechanical Allodynia in Mice

The original version of this article unfortunately contained one error.The authors found that in the middle panel of Fig.2A,the example traces recorded from a contralateral dorsal horn neuron of the capsaicin-treated mouse were wrong,and the corrected Fig.2 was as follows.

Reflections on the Catastrophic 2020 Yangtze River Basin Flooding in Southern China

During the summer of 2020,southern China suffered from catastrophic flooding,the massive basin flood mainly occurred in the Yangtze River's middle and lower reaches.As of July 20,2020,the cumulative precipitation since the rain season started exceeded 500 mm over most of the Yangtze River Basin,reaching>1,200 mm in some areas of the lower reaches,exceeding the same period in 1998,the severest flood year in the past 60 years.Several water gauge stations at Poyang Lake and Chaohu Lake exceeded their historical record values.The water levels in the Wuhan section of the Yangtze River were among the highest ever recorded.As of July 22,2020,45.5 million people had been affected by the floods,with 142 people having died or were missing,and the direct economic losses expected to be around 116 billion RMB(~16.5 billion US dollars).However,the losses from this flood are much lower than those of previous major floods.For example,the catastrophic 1998 flooding led to 1,526 deaths and economic losses of 255 billion RMB(~36.4 billion US dollars).The reasons behind this are worthy of further study and discussion,and may be used for reference in the future and for other countries.

Lin28a is Essential for Synaptic Plasticity in Dentate Granule Cells and Spatial Memory

Dear Editor,The dentate gyrus(DG),a subregion of the hippocampus,is involved in multiple physiological functions such as cognition and mood regulation.Dentate granule cells(DGCs),the primary neurons in the DG,are essential for coding spatial and contextual memories in the hippocampal neural circuits.The entorhinal cortex provides a majority of cortical projections to the DG via the perforant path,and forms synaptic connections with DGCs within the outer two-thirds of the molecular layer of the DG[1].The plasticity of the perforant path-to-DGC synapses strengthens the connections of ensembles encoding spatial,contextual,or temporal information,and promotes the recall of related memories when certain perforant path inputs are reactivated[2].