Defining honeybee subspecies in an evolutionary context warrants strategized conservation

Despite the urgent need for conservation consideration,strategic action plans for the preservation of the Asian honeybee,Apis cerana Fabricius,1793,remain lacking.Both the convergent and divergent adaptations of this widespread insect have led to confusing phenotypical traits and inconsistent infraspecific taxonomy.Unclear subspecies boundaries pose a significant challenge to honeybee conservation efforts,as it is difficult to effectively prioritize conservation targets without a clear understanding of subspecies identities.Here,we investigated genome variations in 362 worker bees representing almost all populations of mainland A.cerana to understand how evolution has shaped its population structure.Whole-genome single nucleotide polymorphisms(SNPs)based on nuclear sequences revealed eight putative subspecies,with all seven peripheral subspecies exhibiting mutually exclusive monophyly and distinct genetic divergence from the widespread central subspecies.Our results demonstrated that most classic morphological traits,including body size,were related to the climatic variables of the local habitats and did not reflect the true evolutionary history of the organism.Thus,such morphological traits were not suitable for subspecific delineation.Conversely,wing vein characters showed relative independence to the environment and supported the subspecies boundaries inferred from nuclear genomes.Mitochondrial phylogeny further indicated that the present subspecies structure was a result of multiple waves of population divergence from a common ancestor.Based on our findings,we propose that criteria for subspecies delineation should be based on evolutionary independence,trait distinction,and geographic isolation.We formally defined and described eight subspecies of mainland A.cerana.Elucidation of the evolutionary history and subspecies boundaries enables a customized conservation strategy for both widespread and endemic honeybee conservation units,guiding colony introduction and breeding.

Lead-free perovskite Cs_(2)AgBiBr_(6)photodetector detecting NIR light driven by titanium nitride plasmonic hot holes

Lead-free perovskite Cs_(2)AgBiBr_(6)manifests great potential in developing high-performance,environmentally friendly,solution-processable photodetectors(PDs).However,due to the relatively large energy bandgap,the spectrum responses of Cs_(2)AgBiBr_(6)PDs are limited to the ultraviolet and visible region with wavelengths shorter than 560 nm.In this work,a broadband Cs_(2)AgBiBr_(6)PD covering the ultraviolet,visible,and near infrared(NIR)range is demonstrated by incorporating titanium nitride(TiN)nanoparticles that are prepared with the assistance of self-assembled polystyrene sphere array.In addition,an atomically thick Al2O3layer is introduced at the interface between the Cs_(2)AgBiBr_(6)film and TiN nanoparticles to alleviate the dark current deterioration caused by nanoparticle incorporation.As a result,beyond the spectrum range where Cs_(2)AgBiBr_(6)absorbs light,the external quantum efficiency(EQE)of the TiN nanoparticle incorporated Cs_(2)AgBiBr_(6)PD is enhanced significantly compared with that of the control,displaying enhancement factors as high as 2000 over a broadband NIR wavelength range.The demonstrated enhancement in EQE arises from the photocurrent contribution of plasmonic hot holes injected from TiN nanoparticles into Cs_(2)AgBiBr_(6).This work promotes the development of broadband solution-processable perovskite PDs,providing a promising strategy for realizing photodetection in the NIR region.

拟线性椭圆系统非径向爆破解的非存在性

该文考虑拟线性椭圆系统△_(pi)u_i+ζ_i(|x|)|▽u_i|^(pi-1)=η_i(|x|)f_i(u_1,…,u_m),其中i=1,…,m,pi≥2,ζ_i和η_i是正连续函数,f_i是非负连续函数且关于每个分量是非减的.通过应用新建立的比较原理证明系统不存在非径向爆破解.

Optimization of Ultrasonic Extraction Conditions of Polyphenols from the Needles of Black Pine (Pinus thunbergii) Using Response Surface Methodology (RSM)

Ultrasonic extraction conditions of polyphenols from the needles of black pine(Pinus thunbergii) were optimized by single factors analysis and Box-Behnken experiment design. The results showed that both of ethanol concentration and ultrasonic time had a significant effect on polyphenol extraction, and there was significant interaction between any two variables in the three parameters of ethanol concentration, ultrasonic temperature and ultrasonic time. The optimal parameters for polyphenol extraction were the ethanol concentration of 52.67%, ultrasonic temperature at 49.21 ℃and ultrasonic time of 30.76 min. Under these conditions, the actual content of polyphenols was close to the predicted value. Therefore, the process can be used to extract polyphenols from black pine needles.

Biotic and abiotic stresses on honeybee health

Honeybees are the most critical pollinators providing key ecosystem services that underpin crop production and sustainable agriculture.Amidst a backdrop of rapid global change,this eusocial insect encounters a succession of stressors during nesting,foraging,and pollination.Ectoparasitic mites,together with vectored viruses,have been recognized as central biotic threats to honeybee health,while the spread of invasive giant hornets and small hive beetles also increasingly threatens colonies worldwide.Cocktails of agrochemicals,including acaricides used for mite treatment,and other pollutants of the environment have been widely documented to affect bee health in various ways.Additionally,expanding urbanization,climate change,and agricultural intensification often result in the destruction or fragmentation of flower-rich bee habitats.The anthropogenic pressures exerted by beekeeping management practices affect the natural selection and evolution of honeybees,and colony translocations facilitate alien species invasion and disease transmission.In this review,the multiple biotic and abiotic threats and their interactions that potentially undermine bee colony health are discussed,while taking into consideration the sensitivity,large foraging area,dense network among related nestmates,and social behaviors of honeybees.

Charge transporting materials for perovskite solar cells

Perovskite solar cells(PSCs) have made great progress since 2009 and become the focus of current research. As an important part of PSCs, charge transporting materials play an important role in the performance of the devices. In this review, we introduce the evolution of electron and hole transporting materials in PSCs in recent years and summarize some typical charge transporting materials and their applications in PSCs. For electron transporting materials, metal oxides(TiO_(2), SnO_(2) and ZnO) and organic materials(fullerenes, non-fullerenes and their derivatives)are the most widely used materials in PSCs. For hole transporting materials, small molecule spiro-OMeTAD(2,2’,7,7’-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9’-spirobifluorene), polymer PEDOT:PSS(poly(3,4-ethylenedioxythiophene): polystyrene sulfonate), PTAA(poly-[bi(4-phenyl)](2,4,3-trimethylphenyla-mine)), P3 HT(poly(3-hexythiophene)) and inorganic materials(NiOx, CuSCN, CuO) are adopted in PSCs. Finally, different types of charge transporting materials are summarized and their future development is prospected.

原子级化学反应促进可弱光探测有机光电倍增探测器的外量子效率超过10^(8)%

外量子效率远大于100%、低成本、溶液法制备的倍增型有机光电探测器(PM-OPDs)引起广泛关注.但该类器件因阳极欧姆接触带来暗电流的恶化,使其弱光探测并不理想.基于此,本文提出了原子级化学反应改善PM-OPDs暗电流及弱光探测策略,进而带来器件综合性能的显著提升.具体地,本文利用原子层沉积技术在空穴传输层PEDOT:PSS与活性层P3HT:PC71BM(100:1)之间引入0.8 nm厚的Al_(2)O_(3)界面层,通过对薄膜拉曼、XPS及FT-IR性能进行表征,发现原子级厚度的Al_(2)O_(3)可与PEDOT:PSS的化学基团发生反应,调节PEDOT:PSS的功函数,进而在阳极一侧形成肖特基接触.通过与阴极肖特基接触协同,器件在保持高倍增行为的同时,暗电流显著降低.最终,器件的弱光探测性能有所改善,相比于标准器件(可探测64 nW/cm^(2)弱光),Al_(2)O_(3)修饰器件可探测低至2.5 nW/cm^(2)的弱光,且相应的外量子效率和响应率分别达到4.31×10^(8)%,1.85×10^(6)A/W,达到目前报道PM-OPDs的最优值.此策略在新型柔性电子产品及医学成像领域具有很好的应用前景.

采用高导热金刚石基底的高效散热钙钛矿激光

具有低温升的高效散热方案是实现电泵浦激光的关键因素之一.高导热金刚石有望克服钙钛矿激光的散热限制.本文中,我们展示了一种可以将光泵浦过程中产生热量高效耗散的金刚石基底钙钛矿纳米片激光.此外,紧密光学束缚可以通过在纳米片和金刚石基底之间引入一层薄SiO_(2)间隔层而实现.该激光的品质因子高达~1962,激光阈值为52.19μJ cm^(-2).受益于金刚石基底,其泵浦能量密度相关温度灵敏度较低(~0.56±0.01 K cm~2μJ^(-1)).本工作有望促进电泵浦钙钛矿激光的发展.

Chiral hierarchical structure of bone minerals

Chirality is an indispensable integral of biological system.As an important part of organisms,chiral organic structure of bone has been extensively investigated.However,the chirality of bone minerals is unclear and not fully determined.Here,we report nine levels of fractal-like chirality of bone minerals by combining electron microscopic and spectrometric characterizations.The primary helically twisted acicular apatite crystals inside collagen fibrils and between fibrils merge laterally to form secondary helical subplatelets.The chiral arrangement of several subplatelets forms tertiary spiral mineral platelets.Further coherent stepwise stacking of mineral platelets with collagen fibrils leads to quaternary to ninth levels,which reconciled the previous conflicting models.The optical activities in the UV-visible,infrared and terahertz regions demonstrated chirality from atomic to macroscopic scales based on circularly selective absorption and Bragg resonance at different levels of chirality.Our findings provide new insight into the structural integrity of bone,osteology,forensic medicine and archaeology and inspire the design of novel biomaterials.

Fiscal Subsidy Policy on Home Appliances: Its Effects on Domestic Consumption and Exports in China

This paper evaluates the effects of the Home Appliances Going to the Countryside (HAGC) policy, afiscal subsidy program implemented in China to boost private consumption of home appliances in rural areas from 2007 to 2012. Using the policy as anatural experiment and employing the difference-in-difference estimator, we find that the policy did not increase domestic sales of relevant goods as expected;instead, it actually reduced domestic sales and significantly promoted exports. These surprising results are robust across regressions of alternative datasets, more controls, and different regions. We further provide detailed information of undisclosed audit data for acounty in Zhejiang province to shed light on the underlying mechanism of such unexpected results, suggesting loopholes in the HAGC and changes in export tax rebate rates.