The Crested Ibises expanding to plain areas exhibit a higher tolerance of human proximity

Animals must strike a balance between anti-predation behavior and other essential behaviors,such as foraging.Within the same species,strategies may vary on individuals’risk-taking preferences,and in this process the environment is a determinant,in addition to predator regime.The Crested Ibis(Nipponia nippon)exhibits such tendency.This is an endangered species,once inhabiting exclusively in China’s Qinling Mountain.This used to be the sole remaining wild population.However,over recent decades,this population has expanded.A portion has relocated to breed in the lower plain area,which is characterized by elevated level of human activities and landscape complexity.We used flight initiation distance(FID)as an indicator of the ibises’risk-taking preference,particularly their response to human proximity.Additionally,we examined the environmental factors influencing their foraging site selection,including altitude,terrain openness,human activity intensity and human construction.Our findings revealed a significantly shorter FID among individuals relocating to plain habitats,indicating a higher tolerance of human proximity.The results showed that FID decreased with distance to the nearest human settlement.Another finding is that FID was independent of instant human activity intensity and environmental factors(altitude and terrain openness).These different may arise from various combinations of human activity,predation risk,and food abundance within the two habitats.These results provide insights into the in situ conservation of the threatened species within the context of global urbanization.

Efficient Environment-friendly Lead-free Tin Perovskite Solar Cells Enabled by Incorporating 4-Fluorobenzylammonium Iodide Additives

Development of tin(Sn)-based perovskite solar cells(PSCs)largely lags behind that of lead counterparts due to fast crystallization process of Sn perovskite and numerous defects in both bulk and surface of Sn perovskite films.Herein,this work reports a facile strategy of introducing 4-fluorobenzylammonium iodide(FBZAI)as additives into Sn perovskite precursor to synergistically modulate the roles of benzylamine and fluorine in Sn-based PSCs.Incorporation of FBZAI can increase crystallinity,passivate defects,and inhibit the oxidation of Sn^(2+),leading to suppression of nonradiative recombination and enhancement of charge transport and collection in devices.As a result,the best-performing Sn-based PSC with the FBZAI additive achieves the maximum PCE of 13.85%with the enhanced fill factor of 77.8%and open-circuit voltage of 0.778 V.Our unencapsulated device exhibits good stability by maintaining 95%of its initial PCE after 160 days of storage.

High level of extra-pair paternity in the socially monogamous Marsh Tits(Poecile palustris)

Background:Extra-pair copulation behavior has been widely studied among socially monogamous birds.Many species revealed high rates of extra-pair paternity.But few of the studies have been carried out in the Asian population.Methods:From 2012 to 2019,we explored the extra-pair paternity of Marsh Tits(Poecile palustris)in Xianrendong National Nature Reserve,Liaoning Province,China.During the study,adult Marsh Tits were captured with mist nets and parental birds,with nest-box traps.Blood samples were taken from the brachial vein.Parentage analyses were carried out using nine highly variable microsatellite loci through Cervus 3.0 software and maximum likelihood approach.Results:Forty-nine offspring(15.08%)from 20 nests(45.45%)were the results of extra-pair fertilization out of a total of 325 offspring in 44 nests.The average extra-pair offspring ratio was 33.54%,with a set varying from 11.11 to 71.43%.Nine extra-pair fathers had been successfully identified,four of whom were the close neighbors of the focus nest while the nests of the remaining five were relatively far.No significant difference was found in the genetic similarity between the social and extra-pair mates of the female,nor in the heterozygosis among the maternal half-siblings.Conclusions:In general,our study proved that the extra-pair paternity in Marsh Tits and its extra-pair mating is independent of the genetic compatibility hypothesis.This complements the understudied bird's extra-pair paternity in Asian area and contributes to the comprehensive insight of birds'extra-pair paternity behaviors.

Interfacial engineering in lead-free tin-based perovskite solar cells

Lead(Pb)-free Tin(Sn)-based perovskite solar cells(PSCs)have been favored by the community due to their low toxicity,preferable bandgaps,and great potential to achieve high power conversion efficiencies(PCEs).Interfaces engineering plays important roles in developing highly efficient Sn-based PSCs via passivation of trap defects,alignment of energy levels,and incorporation of low-dimensional Sn-based perovskites.In this review,we summarize the development of Pb-free Sn-based perovskites and their applications in devices,especially the strategies of improving the interfaces.We also provide perspectives for future research.Our aim is to help the development of new and advanced approaches to achieving high-performance environment-friendly Pb-free Sn-based PSCs.

The spatial distribution and breeding behavior of neighbors affect the reproductive success of tits

The spatial distribution and breeding behavior of neighboring birds(conspecific and heterospecific)may influence reproduction and the effects differ across species.In this study,we investigated intra-and inter-specific spatial distribution of breeding via artificial nestboxes and examined whether overlap with neighbors affected reproductive success of the focal breeding pair.Regarding spatial distribution,Varied Tits(Sittiparus varius)and Cinereous Tits(Parus cinereus)showed similar pattern:distances of nestboxes containing conspecific tits were greater than those with heterospecific ones.In terms of breeding behavior,reproductive success was not significantly related to the distance from their neighbor’s nest.The reproductive success of Varied Tits was significantly related to that of their neighbors,while in Cinereous Tits,no strong link was found to any recorded reproductive behavior of the neighbors.These findings explain spatial variation in nest site selection of Varied Tits and Cinereous Tits.Reproductive success rate of Varied Tits is affected by that of the neighbors while that of Cinereous Tits is not.The results highlight that there are differences in reproductive outcome among related species and offer suggestions on the use of artificial nestboxes in experiment and conservation programs.

Three-dimensional niche partitioning between two colonially nesting ardeid species in central China

Background:Interspecific competition is known to be strongest between those species that are both closely related and sympatric.Egrets are colonially nesting wetland birds that often overlap and can therefore be expected to compete in roosting and nesting habitat as well as in diet.According to the niche partitioning hypothesis,it is to be expected that these similar species would show differentiation in at least one of the main niche dimensions to reduce competition.We tested niche partitioning between the colonially nesting Little Egret(Egretta garzetta)and Cattle Egret(Bubulcus ibis)in temporal,spatial and trophic dimensions.Methods:Field study was conducted in three mixed egret colonies in Yangxian County,southwest Shaanxi Prov-ince,central China.For each nest colony we recorded its spatial location,the height of nesting trees and of nests,the height of roosting trees and of roosting individuals within the trees.We determined the first egg-laying and first hatching dates of the two species.Craw dissection of storm-killed egret nestlings was used to measure the diet.Six transects were surveyed to study foraging habitat selection.Results:We found that hatching time of Little Egrets peaked earlier(by about 1 month)than that of Cattle Egrets.Cattle Egrets nested and roosted higher than Little Egrets.The foraging habitats used by Little Egrets were dominated by river banks(73.49%),followed by paddy fields(13.25%)and reservoirs(10.84%),whereas Cattle Egret foraging sites were characterized by grasslands(44.44%),paddy fields(33.33%)and river banks(22.22%).Little Egrets consumed more fishes(65.66%)and Odonata larvae(13.69%)than Cattle Egrets,while Cattle Egrets were found feeding mainly on Coleoptera(29.69%)and Orthoptera(23.29%).Little Egrets preyed on larger mean biomasses of food items than Cattle Egrets.Conclusions:Our results confirm the niche partitioning hypothesis as a mechanism for coexistence among ecologi-cally similar species.In two coexisting egret species,niche partitioning is multidimensional,such that the two coexist-ent species occupy differing ecological space based on all three temporal,spatial and trophic niche dimensions.

中国入境旅游经济的影响因素分析——基于省际面板数据的实证检验

旅游业是国家或地区之间文化交流与增进友谊的桥梁,而目前我国的入境旅游市场仍存在较大发展空间。本文基于中国2000~2019年31个省市(不包括港澳台地区)的面板数据,实证分析入境旅游经济的影响因素,并进一步比较东部、中部和西部的地区差异。研究结果表明:经济发展水平、产业结构水平、贸易开放度、生态气候条件、旅游接待能力和旅游资源禀赋是促进入境旅游经济发展的重要因素;其中,经济发展水平的促进程度呈现中部、东部和西部递减,生态气候条件则呈现西部、中部、东部递减趋势,而贸易开放度和旅游禀赋程度在西部地区的正向影响程度高于东部地区。

实体企业债务风险评估的主体泛化与信息误导——以华夏幸福为例

传统的企业债务风险分析指标存在主体泛化问题,无法准确体现金融债权人所面临的债务风险。重构的财务分析体系指出,企业应当进一步区分金融债权人的金融性负债与非金融债权人的营业性负债,企业债务风险评估指标应衡量在优先偿还营业性负债的前提下,企业金融债权人所面临的债务风险。这能够在一定程度上解决债务风险测度的平均化问题,更加保守且精准地测度金融债权人的债务风险。通过对具体案例的分析,我们发现:在传统财务风险分析体系下,主体泛化导致的企业债务风险评估信息偏误容易误导企业金融债权人的决策,从而削弱会计信息的决策有用性;而在重构的财务风险分析体系下,从理论上不存在主体泛化导致的信息误导现象,相关指标能够精准评估企业债务风险,提升了会计信息的决策有用性。

Recent progress in perovskite solar cells:material science

Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency.In light of the rapid development of perovskite materials and devices,a systematic survey on the latest advancements covering a broad range of related work is urgently needed.This review summarizes the recent major advances in the research of perovskite solar cells from a material science perspective.The discussed topics include the devices based on different type of perovskites(organic-inorganic hybrid,all-inorganic,and lead-free perovskite and perovskite quantum dots),the properties of perovskite defects,different type of charge transport materials(organic,polymeric,and inorganic hole transport materials and inorganic and organic electron transport materials),counter electrodes,and interfacial materials used to improve the efficiency and stability of devices.Most discussions focus on the key progresses reported within the recent five years.Meanwhile,the major issues limiting the production of perovskite solar cells and the prospects for the future development of related materials are discussed.

Enhancing performance of tin-based perovskite solar cells via fused-ring electron acceptor

The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron acceptor based on indacenodithiophene(IDIC)was for the first time introduced as a transition layer between a tin-based perovskite layer and a C 60 electron transport layer,leading to better matched energy levels in the device.In addition,coordination interactions between IDIC and perovskite improved the latter's crystallinity.The introduction of IDIC raised the power conversion efficiency from 8.98%to 11.5%and improved the device's stability.The decomposition mechanism of tin-based perovskite was also revealed by detecting the optical properties of perovskite microdomains through innovative integration of confocal laser scanning microscopy and photoluminescence spectroscopy.

DNA Dumbbell and Chameleon Silver Nanoclusters for miRNA Logic Operations

Multiplex miRNA analysis is a fundamental issue for exploring a complex biological system and early diagnosis of miRNA-related diseases.Herein,we have developed a series of novel logic gates for miRNA analysis coupling DNA nanostructures and chameleon silver nanoclusters(AgNCs).DNA dumbbell structures are firstly designed with two independent nucleation sequences for AgNCs at the 5′and 3′ends,respectively.By introducing different miRNA inputs,separations of two AgNCs are controlled and the fluorescence property of AgNCs changes.By studying the ratiometric fluorescence responses,sensitive and selective analysis of multiple miRNAs can be achieved.The present work provides powerful tools for miRNA diagnostics and may also guide future DNA nanostructure-based logic gates.