“预聘-长聘制”对高校科研产出的影响机制与成效分析

近年来,我国部分高校实施了以"预聘-长聘制"为核心的教师聘任制度改革,促进高水平科研成果产出是这一改革的重要目标之一。研究利用布兰德科研生产力三因素影响模型,从教师个体、组织机构、学术共同体三个层面论证了改革对科研产出的正向促进作用,并以71所研究型大学为研究对象,借助改革准实验进行定量研究。研究发现,第一,实行"预聘-长聘制"后,已改革高校的国际期刊论文发表量和论文影响力指数(CNCI)都得到了显著提高;第二,实行"预聘-长聘制"后,已改革高校发表论文的数量并无显著优势,但其论文影响力明显高于未改革高校。

Nocturnal Low-levelWinds and Their Impacts on Particulate Matter over the Beijing Area

Three-month wind profiles, 260 m PM_1 concentrations [i.e., particulate matter(PM) with an aerodynamic diameter ≤1μm], and carrier-to-noise ratio data at two Beijing sites 55 km apart(urban and suburban) were collected to analyze the characteristics of low-level nocturnal wind and PM in autumn and winter. Three mountain-plain wind events with wind shear were selected for analysis. The measurements indicated that the maximum wind speeds of the northerly weak low-level jet(LLJ) below 320 m at the suburban site were weaker than those at the urban site, and the LLJ heights and depths at the suburban site were lower than those at the urban site. The nocturnal 140 m mean vertical velocities and the variations in vertical velocity at the urban site were larger than those at the suburban site. A nocturnal breeze with a weak LLJ of ～3 m s^(-1) noticeably offset nocturnal PM transport due to southerly flow and convergence within the northern urban area of Beijing. Characteristics of the nocturnal LLJ, such as start-up time, structure, intensity, and duration, were important factors in determining the decrease in the nocturnal horizontal range and site-based low-level variations in PM.

A Monophyletic Status of Axis Genus in Subfamily Cervinae Supported by the Complete Mitochondrial Genome of Chinese Hog Deer(Axis porcinus)

Hog deer(Axis porcinus)is a small mammal and listed in the International Union for Conservation of Nature.However,phylogenetic position of hog deer within Axis genus has remained controversial.In the present study,we first assembled complete mitochondrial genome of Chinese hog deer reared in Chengdu Zoo,Sichuan,by the second-generation sequencing technology.This newly assembled mitochondrial genome of hog deer is 16376 bp in length and consists of 13 protein-encoding genes,23 transfer RNA genes and 2 ribosomal RNA genes.Phylogenetic analyses based on complete mitochondrial genome and cytochrome b gene sequences revealed that hog deer is closely clustered together and placed with sister taxon of spotted deer(A.Axis),which therefore supported monophyletic statue of Axis genus.Furthermore,considerable genetic differentiation,up to 139 mutations of complete mitochondrial genome was revealed between geographical populations of hog deer in France and Southeast Asia.However,only six variable sites(nucleotide diversity of 0.00007)and four haplotypes(haplotype diversity of 0.533)were totally detected among ten newly sequenced Chinese hog deer.The results provide a better understanding on the phylogeny of hog deer.

彝良县水稻三化螟发生特点与测控效应

水稻螟虫是彝良县水稻生产上的重要虫害之一。文章阐述水稻三化螟在彝良县的发生危害特点、影响因素、预测方法与防控技术及其测控效应,以期为其它病虫测报与持续控制提供借鉴。

Chromatin Remodeling Factor SMARCA5 is Essential for Hippocampal Memory Maintenance via Metabolic Pathways in Mice

Gene transcription and new protein synthesis regulated by epigenetics play integral roles in the formation of new memories.However,as an important part of epigenetics,the function of chromatin remodeling in learning and memory has been less studied.Here,we showed that SMARCA5(SWI/SNF related,matrix-associated,actin-dependent regulator of chromatin,subfamily A,member 5),a critical chromatin remodeler,was responsible for hippocampus-dependent memory maintenance and neurogenesis.Using proteomics analysis,we found protein expression changes in the hippocampal dentate gyrus(DG)after the knockdown of SMARCA5 during contextual fear conditioning(CFC)memory maintenance in mice.Moreover,SMARCA5 was revealed to participate in CFC memory maintenance via modulating the proteins of metabolic pathways such as nucleoside diphosphate kinase-3(NME3)and aminoacylase 1(ACY1).This work is the first to describe the role of SMARCA5 in memory maintenance and to demonstrate the involvement of metabolic pathways regulated by SMARCA5 in learning and memory.

Characteristics of one-year observation of VOCs,NOx, and O_3 at an urban site in Wuhan, China

A continuous online observation of ozone and its precursors(NOx, VOCs) was carried out in central urban Wuhan from September 2016 to August 2017. The concentration levels of ozone,NOx, VOCs and their variations in urban Wuhan were analyzed, as well as effects of VOCs on ozone photochemical generation and the main controlling factors for ozone production. During the observation period, the average concentrations of ozone and NOx in Wuhan was 22.63 and30.14 ppbv, respectively, and the average concentration of VOCs was 32.61 ppbv(42.3% alkanes,13.0% alkenes, 10.0% aromatics, 7.3% acetylene, 9.9% OVOCs, and 10.5% halohydrocarbons).Ozone concentration was higher in spring and summer as compared with autumn and winter,wheras VOCs and NOx concentratios were lower in spring and summer but higher in autumn and winter. Aromatics and alkenes, two of VOCs species, showed the highest contributions to ozone formation potential in Wuhan(35.7% alkenes, 35.4 aromatics, 17.5% alkanes, 8.6% OVOCs,1.6% halogenated hydrocarbons, and 1.4% acetylene). Among all VOCs species, those with the highest contribution were ethylene, m-xylene, toluene, propylene and o-xylene. The contribution of these five compounds to the total ozone formation potential concentration was 43.90%.Ozone-controlling factors in Wuhan changed within one day; during the early morning hours(6:00–9:00), VOCs/NOx was low, and ozone generation followed a VOCs-limited regime.However, during the peak time of ozone concentration(12:00–16:00), the ratio of VOCs/NOx was relatively high, suggesting that ozone generation followed a NOx-limited regime.

Chemical characteristics of size-resolved aerosols in winter in Beijing

Size-resolved aerosols were continuously collected by a Nano Sampler for 13 days at an urban site in Beijing during winter 2012 to measure the chemical composition of ambient aerosol particles. Data collected by the Nano Sampler and an ACSM（Aerodyne Aerosol Chemical Speciation Monitor） were compared. Between the data sets,similar trends and strong correlations were observed,demonstrating the validity of the Nano Sampler. PM10 and PM2.5concentrations during the measurement were 150.5 ± 96.0 μg/m3（mean ± standard variation）and 106.9 ± 71.6 μg/m3,respectively. The PM2.5/PM10 ratio was 0.70 ± 0.10,indicating that PM2.5dominated PM10. The aerosol size distributions showed that three size bins of 0.5–1,1–2.5 and 2.5–10 μm contributed 21.8%,23.3% and 26.0% to the total mass concentration（TMC）,respectively. OM（organic matter） and SIA（secondary ionic aerosol,mainly SO42-,NO3-and NH4＋） were major components of PM2.5. Secondary compounds（SIA and secondary organic carbon） accounted for half of TMC（about 49.8%） in PM2.5,and suggested that secondary aerosols significantly contributed to the serious particulate matter pollution observed in winter. Coal burning,biomass combustion,vehicle emissions and SIA were found to be the main sources of PM2.5. Mass concentrations of water-soluble ions and undetected materials,as well as their fractions in TMC,strikingly increased with deteriorating particle pollution conditions,while OM and EC（elemental carbon） exhibited different variations,with mass concentrations slightly increasing but fractions in TMC decreasing.

Aerosol optical properties under different pollution levels in the Pearl River Delta(PRD) region of China

To clarify the aerosol hygroscopic growth and optical properties of the Pearl River Delta(PRD)region,integrated observations were conducted in Heshan City of Guangdong Province from October 19 to November 17,2014.The concentrations and chemical compositions of PM2.5,aerosol optical properties and meteorological parameters were measured.The mean value of PM2.5 increased from less than 35(excellent)to 35-75μg/m^3(good)and then to greater than 75μg/m^3(pollution),corresponding to mean PM2.5 values of 24.9,51.2,and 93.3μg/m^3,respectively.The aerosol scattering hygroscopic growth factor(f(RH=80%))values were 2.0,2.12,and 2.18 for the excellent,good,and pollution levels,respectively.The atmospheric extinction coefficient(σext)and the absorption coefficient of aerosols(σap)increased,and the single scattering albedo(SSA)decreased from the excellent to the pollution levels.For different air mass sources,under excellent and good levels,the land air mass from northern Heshan had lower f(RH)andσsp values.In addition,the mixed aerosol from the sea and coastal cities had lower f(RH)and showed that the local sources of coastal cities have higher scattering characteristics in pollution periods.

Effect of potential HONO sources on peroxyacetyl nitrate(PAN)formation in eastern China in winter

As an important secondary photochemical pollutant,peroxyacetyl nitrate(PAN)has been studied over decades,yet its simulations usually underestimate the corresponding observations,especially in polluted areas.Recent observations in north China found unusually high concentrations of PAN during wintertime heavy haze events,but the current model still cannot reproduce the observations,and researchers speculated that nitrous acid(HONO)played a key role in PAN formation.For the first time we systematically assessed the impact of potential HONO sources on PAN formation mechanisms in eastern China using the Weather Research and Forecasting/Chemistry(WRF-Chem)model in February of 2017.The results showed that the potential HONO sources significantly improved the PAN simulations,remarkably accelerated the RO x(sum of hydroxyl,hydroperoxyl,and organic peroxy radicals)cycles,and resulted in 80%–150%enhancements of PAN near the ground in the coastal areas of eastern China and 10%–50%enhancements in the areas around 35–40°N within 3 km during a heavy haze period.The direct precursors of PAN were aldehyde and methylglyoxal,and the primary precursors of PAN were alkenes with C>3,xylenes,propene and toluene.The above results suggest that the potential HONO sources should be considered in regional and global chemical transport models when conducting PAN studies.

Role of secondary aerosols in haze formation in summer in the Megacity Beijing

A field experiment from 18 August to 8 September 2006 in Beijing, China, was carried out. A hazy day was defined as visibility 〈 10 km and RH（relative humidity） 〈 90%. Four haze episodes, which accounted for ～ 60% of the time during the whole campaign, were characterized by increases of SNA（sulfate, nitrate, and ammonium） and SOA（secondary organic aerosol） concentrations. The average values with standard deviation of SO2-＋4, NO-3, NH4 and SOA were 49.8（± 31.6）, 31.4（±22.3）, 25.8（±16.6） and 8.9（±4.1） μg/m3, respectively, during the haze episodes, which were 4.3, 3.4, 4.1, and 1.7 times those in the non-haze days. The SO2-4,NO-3, NH＋4, and SOA accounted for 15.8%, 8.8%, 7.3%, and 6.0% of the total mass concentration of PM10 during the non-haze days. The respective contributions of SNA species to PM10 rose to about27.2%, 15.9%, and 13.9% during the haze days, while the contributions of SOA maintained the same level with a slight decrease to about 4.9%. The observed mass concentrations of SNA and SOA increased with the increase of PM10 mass concentration, however, the rate of increase of SNA was much faster than that of the SOA. The SOR（sulfur oxidation ratio） and NOR（nitrogen oxidation ratio） increased from non-haze days to hazy days, and increased with the increase of RH. High concentrations of aerosols and water vapor favored the conversion of SO2 to SO2-4and NO2 to NO-3, which accelerated the accumulation of the aerosols and resulted in the formation of haze in Beijing.

Chemical characterization of size-resolved aerosols in four seasons and hazy days in the megacity Beijing of China

Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m^3, respectively,throughout the measurement, with seasonal variation： nearly two times higher in autumn than in summer and spring. Serious fine particle pollution occurred in winter with the PM1.8/PM10 ratio of 0.63, which was higher than other seasons. The size distribution of PM showed obvious seasonal and diurnal variation, with a smaller fine mode peak in spring and in the daytime. OM（organic matter = 1.6 × OC（organic carbon）） and SIA（secondary inorganic aerosol） were major components of fine particles, while OM, SIA and Ca^2＋were major components in coarse particles. Moreover, secondary components, mainly SOA（secondary organic aerosol） and SIA,accounted for 46%-96% of each size bin in fine particles, which meant that secondary pollution existed all year. Sulfates and nitrates, primarily in the form of（NH4）2SO4, NH4NO3, Ca SO4, Na2SO4 and K2SO4, calculated by the model ISORROPIA II, were major components of the solid phase in fine particles. The PM concentration and size distribution were similar in the four seasons on non-haze days, while large differences occurred on haze days, which indicated seasonal variation of PM concentration and size distribution were dominated by haze days. The SIA concentrations and fractions of nearly all size bins were higher on haze days than on non-haze days, which was attributed to heterogeneous aqueous reactions on haze days in the four seasons.

Insights into the phenomenon of an explosive growth and sharp decline in haze:A case study in Beijing

A severe haze episode occurred in winter in the North China Plain(NCP),and the phenomenon of an explosive growth and sharp decline in PM2.5(particulate matter with an aerodynamic diameter equal to or less than 2.5μm)concentration was observed.To study the systematic causes for this phenomenon,comprehensive observations were conducted in Beijing from November 26 to December 2,2015;during this period,meteorological parameters,LIDAR data,and the chemical compositions of aerosols were determined.The haze episode was characterized by rapidly varying PM2.5 concentration,and the highest PM2.5 concentration reached 667μg/m3.During the haze episode,the NCP was dominated by a weak high-pressure system and continuously low PBL(planetary boundary layer)heights,which are unfavorable conditions for the diffusion of pollutants.The large increases in the concentrations of SNA(SO42-,NO3-and NH4+)during the haze implied that the formation of SNA was the largest contribution.Water vapor also played a vital role in the formation of haze by promoting the chemical transformation of secondary pollutants,which led to higher PM2.5 concentrations.The spatial distributions of PM2.5 in Beijing at different times and the backward trajectories of the air masses also indicated that pollutants from surrounding provinces in particular,contributed to the higher PM2.5concentration.

Chemical and optical properties of aerosols and their interrelationship in winter in the megacity Shanghai of China

A field campaign on air quality was carried out in Shanghai in winter of 2012. The concentrations of NO, NO2, NOx, SO2, CO, and PM2.5increased during haze formation. The average masses of SO4^2-, NO3^-and NH4^＋were 10.3, 11.7 and 6.7 μg/m^3 during the haze episodes, which exceeded the average（9.2, 7.9, and 3.4 μg/m3） of these components in the non-haze days. The mean values for the aerosol scattering coefficient（b sp）, aerosol absorption coefficient（b ap） and single scattering albedo（SSA） were 288.7, 27.7 and0.91 Mm-1, respectively. A bi-peak distribution was observed for the mass concentrations of CO, NO, NO2, and NOx. More sulfate was produced during daytime than that in the evening due to photochemical reactions. The mass concentration of NH4＋achieved a small peak at noontime. NO3-showed lower concentrations in the afternoon and higher concentrations in the early morning. There were obvious bi-peak diurnal patterns for b sp and b ap as well as SSA. b sp and b ap showed a positive correlation with PM2.5mass concentration.（NH4）2SO4, NH4NO3, organic mass, elemental carbon and coarse mass accounted for 21.7%, 19.3%, 31.0%, 9.3% and 12.3% of the total extinction coefficient during non-haze days, and 25.6%, 24.3%, 30.1%, 8.1% and 8.2% during hazy days. Organic matter was the largest contributor to light extinction. The contribution proportions of ammonium sulfate and ammonium nitrate to light extinction were significantly higher during the hazy time than during the non-haze days.

Characteristics and formation mechanism of regional haze episodes in the Pearl River Delta of China

To investigate the characteristics and the specific mechanism of continuous haze,comprehensive measurements were conducted from 15 October to 19 November in the Atmospheric Environment Monitoring Super-Station in Heshan of Guangdong province.Five haze episodes occurred in October and November 2014 in the Pearl River Delta（PRD）region. The meteorological parameters, gas data, chemical compositions, and optical parameters of the aerosols were obtained. Among these events, the second haze episode,with the highest concentration of PM2.5 of 187.51 μg/m^3, was the most severe. NO^3-was always higher than SO_4^（2-）, which indicated that motor vehicles played an important role in the haze, even though the oxidation rate from SO_2 to SO_4^（2-）was faster than that of NOXto NO_3^-. The difference between the hourly averages of Na＋and K＋during the haze episode and clean days was small, implying that straw combustion and sea salt had no significant effect on the occurrence of haze, and the backward trajectories of the air masses also conformed with this result. The air pollutants were difficult to disperse because of the significant decrease in the planetary boundary layer（PBL） height. Relative humidity played a crucial role in the formation of haze by leading to hygroscopic growth of the diameter of aerosols.

An overview of emissions of SO2 and NOx and the long-range transport of oxidized sulfur and nitrogen pollutants in East Asia

The long-range transport of oxidized sulfur（sulfur dioxide（SO2） and sulfate） and oxidized nitrogen（nitrogen oxides（NOx ） and nitrate） in East Asia is an area of increasing scientific interest and political concern. This paper reviews various published papers, including ground- and satellite-based observations and numerical simulations. The aim is to assess the status of the anthropogenic emissions of SO2 and NOx and the long-range transport of oxidized S and N pollutants over source and downwind region. China has dominated the emissions of SO2 and NOx in East Asia and urgently needs to strengthen the control of their emissions, especially NOx emissions. Oxidized S and N pollutants emitted from China are transported to Korea and Japan, due to persistent westerly winds, in winter and spring.However, the total contributions of China to S and N pollutants across Korea and Japan were not found to be dominant over longer time scales（e.g., a year）. The source–receptor relationships for oxidized S and N pollutants in East Asia varied widely among the different studies. This is because：（1） the nonlinear effects of atmospheric chemistry and deposition processes were not well considered, when calculating the source–receptor relationships;（2） different meteorological and emission data inputs and solution schemes for key physical and chemical processes were used; and（3） different temporal and spatial scales were employed. Therefore, simulations using the same input fields and similar model configurations would be of benefit, to further evaluate the source–receptor relationships of the oxidized S and N pollutants.

Synergistic impacts of anthropogenic and biogenic emissions on summer surface O_3 in East Asia

A factor separation technique and an improved regional air quality model （RAQM） were applied to calculate synergistic contributions of anthropogenic volatile organic compounds （AVOCs）,biogenic volatile organic compounds （BVOCs） and nitrogen oxides （NOx） to daily maximum surface O3（O3DM） concentrations in East Asia in summer （June to August 2000）.The summer averaged synergistic impacts of AVOCs and NOx are dominant in most areas of North China,with a maximum of 60 ppbv,while those of BVOCs and NOx are notable only in some limited areas with high BVOC emissions in South China,with a maximum of 25 ppbv.This result implies that BVOCs contribute much less to summer averaged O3DM concentrations than AVOCs in most areas of East Asia at a coarse spatial resolution （1×1） although global emissions of BVOCs are much greater than those of AVOCs.Daily maximum total contributions of BVOCs can approach 20 ppbv in North China,but they can reach 40 ppbv in South China,approaching or exceeding those in some developed countries in Europe and North America.BVOC emissions in such special areas should be considered when O3 control measures are taken.Synergistic contributions among AVOCs,BVOCs and NOx significantly enhance O3 concentrations in the Beijing-Tianjin-Tangshan region and decrease them in some areas in South China.Thus,the total contributions of BVOCs to O3DM vary significantly from day to day and from location to location.This result suggests that O3 control measures obtained from episodic studies could be limited for long-term applications.

Manganese silicate nanospheres-incorporated hydrogels:starvation therapy and tissue regeneration

To prevent postoperative skin tumor recurrence and repair skin wound,a glucose oxidase(GOx)-loaded manganese silicate hollow nanospheres(MS HNSs)-incorporated alginate hydrogel(G/MS-SA)was constructed for starvation-photothermal therapy and skin tissue regeneration.The MS HNSs showed a photothermal conversion efficiency of 38.5%,and endowed composite hydrogels with satisfactory photothermal effect.Taking advantage of the catalytic activity of Mn ions,the composite hydrogels could decompose hydrogen peroxide(H2O2)into oxygen(O2),which can alleviate the problem of tumor hypoxia microenvironment and endow GOx with an ability to consume glucose in the presence of O2 for tumor starvation.Meanwhile,hyperthermia triggered by near infrared(NIR)irradiation could not only accelerate the reaction rate of H2O2 decomposition by MS HNSs and glucose consumption by GOx,but also ablate tumor cells.The anti-tumor results showed that synergistic effect of starvation-photothermal therapy led to the highest death rate of tumor cells among all groups,and its anti-tumor effect was obviously improved as compared with that of single photothermal treatment or starvation treatment.Interestingly,the introduction of MS HNSs into hydrogels could distinctly promote the epithelialization of the wound beds by releasing Mn ions as compared with the hydrogels without MS HNSs.It is expected that such a multifunctional platform with starvation-photothermal therapy will be promising for treating tumor-caused skin defects in combination of its regeneration bioactivity in the future.

‘Aerosol optical properties under different pollution levels in the pearl river delta(PRD)region of China’J.Environ.Sci.87(2020)49–59

The authors regret<In Abstract"The mean value of PM 2.5 increased from less than 35(excellent)to 35–75μg/m^(3)(good)and then to greater than 75μg/m^(3)(pollution),corresponding to mean PM 2.5 values of 24.9,51.2 and 93.3μg/m^(3),respectively.The aerosol scattering hygroscopic growth factor(f(RH=80%))values were 2.0,2.12 and 2.18 for the excellent,good and pollution levels,respectively."should be revised to"The mean value of PM 2.5(24-hr)increased from less than 35μg/m^(3)(excellent)to 35–75μg/m^(3)(good)and then to greater than 75μg/m^(3)(pollution),corresponding to mean PM 2.5 values of 24.9,51.2 and 93.3μg/m^(3),respectively.The aerosol scattering hygroscopic growth factor(f(RH=80%))values were 2.69,2.33 and 2.09 for the excellent,good and pollution levels,respectively."

大学评估何处去?国际评估在中国一流大学的兴起、扩散与制度化

一、导言从20世纪80年代开始,伴随高等教育外部环境变化,如高等教育进入大众化阶段、外部资源竞争加剧社会对高等教育质量保障的日益关注等,越来越多的大学开始经历主动或被动的评估,在英国学者Gregory看来,20世纪80年代甚至可以被视为倡议大学评估的十年。在中国也是如此,早在1985年的《中共中央关于教育体制改革的决定》中,就提出“定期对高等学校的办学水平进行评估”。