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.

Effect of Sr^(2+)on 3D gel-printed Sr_(3-x)Mg_(x)(PO_(4))_(2)composite scaffolds for bone tissue engineering

Porous magnesium strontium phosphate(Sr_(3-x)Mg_(x)(PO_(4))_(2))(x=2,2.5,3)composite scaffolds were successfully prepared by three dimension gel-printing(3DGP)method in this study.The results show that Sr_(0.5)Mg_(2.5)(PO_(4))_(2)scaffolds had good compressive strength,and Sr_(1.0)Mg_(2.0)(PO_(4))_(2)scaffolds had good degradation rate in vitro.The weight loss rate of Sr_(1.0)Mg_(2.0)(PO_(4))_(2)scaffolds soaked in simulated body fluid(SBF)or 6 weeks was 6.96%,and pH value varied between 7.50 and 8.61,which was within the acceptable range of human body.Preliminary biological experiment shows that MC3T3-E1 cells had good adhesion and proliferation on the surface of Sr_(3-x)Mg_(x)(PO_(4))_(2)scaffolds.Compared with pure Mg3(PO_(4))_(2)scaffolds,strontium doped scaffolds had excellent comprehensive properties,which explain that Sr_(3-x)Mg_(x)(PO_(4))_(2)composite scaffolds can be used for bone tissue engineering.

Double-layer Bayesian Classifier Ensembles Based on Frequent Itemsets

Numerous models have been proposed to reduce the classification error of Naive Bayes by weakening its attribute independence assumption and some have demonstrated remarkable error performance. Considering that ensemble learning is an effective method of reducing the classifmation error of the classifier, this paper proposes a double-layer Bayesian classifier ensembles （DLBCE） algorithm based on frequent itemsets. DLBCE constructs a double-layer Bayesian classifier （DLBC） for each frequent itemset the new instance contained and finally ensembles all the classifiers by assigning different weight to different classifier according to the conditional mutual information. The experimental results show that the proposed algorithm outperforms other outstanding algorithms.

Satellite estimates and subpixel variability of rainfall in a semi-arid grassland

卫星估雨精度的不确定性受到当地降雨类型和像元内降雨非均匀性影响,而结合这两个关键因素开展半干旱草原卫星估雨的研究有限.2009年夏,我们在中国锡林郭勒半干旱草原用多部微雨雷达和雨量计构建了9 km卫星像元降雨观测网,观测了像元内降雨非均匀性(空间变异系数CV),并评估了卫星估雨精度.结果表明:(1) CV值受像元内平均降雨量,降雨类型,降雨云面积及移向等影响,如高CV值的降雨过程大多为平均降雨量小,对流性降雨过程,降雨云边缘像元CV值较高;(2) TRMM 3B42V7卫星估雨产品适用性较好,CMORPH和PERSIANN次之,但TRMM3B42V7易在半干旱草原湖泊处高估降雨.

FACT:An Air-Ground Communication Framework for Seeding Quality Control of Aircraft

A new type of air-ground communication application framework named FACT(framework for air-ground communication technology with weather-modification aircraft)is presented to track and command weather-modification aircraft to perform ideal cloud seeding.FACT provides a set of solutions from three perspectives,namely,onboard,onground and air-to-ground,with the core purpose of solving the problems of the rapid exchange of information,contract analysis and identifying potential seeding areas when flight plans and meteorological conditions change.On board,the observed data are processed centrally and transmitted downward through air-to-ground communication.The real-time application and sharing of aircraft detection data are strengthened on the ground,and potential areas of operation are automatically identified based on ground data.The communication between the air and the ground achieves a technical breakthrough by realizing double satellite links,adaptive data transmission and VPN channel encryption.Additionally,an application based on FACT is designed and implemented for the real-time command of weather-modified aircraft.This approach has become the key air-to-ground communication system support for more than 40 Chinese aircraft and the big data service support center of airborne data to ensure improved operation of weather-modification aircraft in China.

Observation of Wind Shear during Evening Transition and an Estimation of Submicron Aerosol Concentrations in Beijing Using a Doppler Wind Lidar

The wind speed and direction measured over six months by a Doppler wind lidar（Windcube-8）were compared with wind cup anemometers mounted on the 325-m Beijing meteorological tower（BMT）.Five mountain–plain wind cases characterized by wind direction shear were selected based on the high-frequency（1.1 s）wind profile of the Windcube-8 and analyzed with 1-h mesoscale surface weather charts.Also analyzed was the relationship between insitu PM_1（aerodynamic diameter≤1μm）concentrations measured at 260 m on BMT and the carrier-to-noise ratio（CNR）of the co-located Windcube-8.The results showed that the 10-min averaged wind speed and direction were highly correlated（R=0.96–0.99）at three matched levels（80,140,and 200 m）.The evening transition duration was1–3 h,with an average wind speed of 1 m s^（–1） at 80 m above the ground.In addition,there was a zero horizontalwind-speed zone along the wind direction shear line,and in one case,the wind speed was characterized by a Kelvin–Helmholtz gravity wave.The variability of the PM_1 concentrations was captured by the CNR of the Windcube-8 in a fair weather period without the long-range transport of dust.

论当代非洲文学对外国文学课程的补充与拓新

在国际化、全球化发展的大背景下,培养具有文化理解力和沟通能力的外语人才变得愈发重要。随着2013年“一带一路”倡议的提出,一方面中非经贸交流越来越频繁与深入,另一方面在文化交流上,出现了当代非洲文学在国际文坛上崛起与我国外国文学课程中相应内容的缺失形成的鲜明反差。本文介绍了当代非洲文学的复杂性与世界性两个总体特征,对国内外国文学课程设置的现状进行了描述,并论述了当代非洲文学对外国文学课程的补充与拓新意义。

Computing payment for ecosystem services in watersheds: An analysis of the Middle Route Project of South-to-North Water Diversion in China

Payment for ecosystem services （PES） has attracted considerable attention as an economic incentive for promoting natural resource management recently. As emphasis has been placed on using the incentive-based mechanism by the central government, rapid progress on PES research and practice has been achieved. However PES still faces many difficulties. A key issue is the lack of a fully-fledged theory and method to clearly define the design scope, accounting and feasibility of PES criteria. An improved watershed criteria model was developed in light of research on PES practices in China, investigations on the water source area for the Middle Route Project of South-to-North Water Diversion and ecosystem services outflows theory. The basic principle of assessment is the direct and opportunity cost for ecological conservation and environmental protection in the water source area deduct nationally-financed PES and internal effect. Then the scope and the criteria methods were determined, and internal effect was put forward to define benefits brought from water source area. Finally, Shiyan City, which is the main water source area for the Project of Water Diversion, was analyzed by this model and its payment was calculated. The results showed that： （1） during 2003–2050, the total direct cost and opportunity cost would reach up to 262.70 billion and 256.33 billion Chinese Yuan （CNY, 2000 constant prices）, i.e., 50.61% and 49.38% of total cost, respectively; （2） Shiyan City would gain 0.23, 0.06 and 0.03 CNY/m3 in 2014–2020, 2021–2030, and 2031–2050, respectively.

Isolation and identification of sinapine-degrading bacteria from the intestinal tract of laying hens

This study was aimed to isolate sinapine-degrading bacteria from the intestinal tract of laying hens and to identify the predominant bacteria. Thirty-week old healthy laying hens were killed, and the chyme in the digestive tract was inoculated into modified Czapek medium containing sinapin and cultivated at 37 ℃for 10 days. The optical density(OD) values of the bacterial solutions at different cultivating times were detected by a spectrophotometric method. The predominant strains were identified by 16 S rRNA gene analysis. We extracted the extracellular products of the predominant strains to determine the total protein using the Coomassie brilliant blue method, and to determine the activities of some extracellular enzymes using the agar plate diffusion method. Nine strains were isolated from the lower intestinal tract of laying hens. Among the 9 strains, 5 were from the ileum, 2 were from the ceca and 2 were from the jejunum. We could not isolate any strains from the upper intestinal tract, such as the stomach and duodenum. Eight of those 9 isolated strains were gram negative and one was gram positive. Strains YD-1 and YD-2 were better than other strains in their abilities to degrade sinapine. Strains YD-1 and YD-2 were identified as Escherichia coli and Klebsiella spp., respectively, by the 16 S rRNA sequence analysis.The total protein level of the extracellular products was 1.213 g/L for YD-1 and 1.990 g/L for YD-2. Both extracellular products of YD-1 and YD-2 had the activities of protease, amylase and urease. This study confirmed that the primary site of sinapine degradation is in the lower intestinal tract of laying hens. The sinapine-degrading strains are mainly gram negative. Strains YD-1 and YD-2 are predominant in degrading sinapine and they belong to E. coli and Klebsiella spp., respectively. Both extracellular products of YD-1 and YD-2 contain protease, amylase and urease. Strain YD-2 is better than strain YD-1 in its ability to degrade sinapine.

Development of a test strip based on DNA-functionalized gold nanoparticles for rapid detection of mercury(II) ions

快速、敏感、选择、可靠的长带试金基于为 Hg2+ 察觉的 DNA-functionalized 金 nanoparticles 被开发了，与察觉限制 5 nmol/L。测量原则基于 thymineHg2+thymine (THg2+T ) 协作化学和 streptavidinbiotin 相互作用。这试金的主要优点是没有任何仪器，结果能在不到 10 min 视觉上被读并且它不要求任何样品预告的处理。

Development of stem cell-based therapy for Parkinson’s disease

Parkinson’s disease(PD)is one of the most common neurodegenerative disorders of aging,characterized by the degeneration of dopamine neurons(DA neurons)in the substantial nigra,leading to the advent of both motor symptoms and non-motor symptoms.Current treatments include electrical stimulation of the affected brain areas and dopamine replacement therapy.Even though both categories are effective in treating PD patients,the disease progression cannot be stopped.The research advance into cell therapies provides exciting potential for the treatment of PD.Current cell sources include neural stem cells(NSCs)from fetal brain tissues,human embryonic stem cells(hESCs),induced pluripotent stem cells(iPSCs)and directly induced dopamine neurons(iDA neurons).Here,we evaluate the research progress in different cell sources with a focus on using iPSCs as a valuable source and propose key challenges for developing cells suitable for large-scale clinical applications in the treatment of PD.

Use of Whole-Exome Sequencing for the Diagnosis of Atypical Birte-Hogge-Dubé Syndrome

Destruction of the lung parenchyma may result in the forma- tion of cysts, cavities and bullae. Definition of the type of destructive lesion is best achieved by high-resolution computed tomography （HRCT） scans of the chest （Trotman- Dickenson, 2014）. The loss of lung parenchyma may result in respiratory compromise and pneumothoraces. In the case of cystic lung destruction, multiple causes have been identified, with the cysts being a manifestation of inherited and non- inherited diseases （Sahn and Heffner, 2000）. Compared with sporadic cases, familial lung cysts/spontaneous pneumothorax are rare and are manifestation of some Mendelian genetic diseases.