Identification of Convective and Stratiform Clouds Based on the Improved DBSCAN Clustering Algorithm

A convective and stratiform cloud classification method for weather radar is proposed based on the density-based spatial clustering of applications with noise(DBSCAN)algorithm.To identify convective and stratiform clouds in different developmental phases,two-dimensional(2D)and three-dimensional(3D)models are proposed by applying reflectivity factors at 0.5°and at 0.5°,1.5°,and 2.4°elevation angles,respectively.According to the thresholds of the algorithm,which include echo intensity,the echo top height of 35 dBZ(ET),density threshold,andεneighborhood,cloud clusters can be marked into four types:deep-convective cloud(DCC),shallow-convective cloud(SCC),hybrid convective-stratiform cloud(HCS),and stratiform cloud(SFC)types.Each cloud cluster type is further identified as a core area and boundary area,which can provide more abundant cloud structure information.The algorithm is verified using the volume scan data observed with new-generation S-band weather radars in Nanjing,Xuzhou,and Qingdao.The results show that cloud clusters can be intuitively identified as core and boundary points,which change in area continuously during the process of convective evolution,by the improved DBSCAN algorithm.Therefore,the occurrence and disappearance of convective weather can be estimated in advance by observing the changes of the classification.Because density thresholds are different and multiple elevations are utilized in the 3D model,the identified echo types and areas are dissimilar between the 2D and 3D models.The 3D model identifies larger convective and stratiform clouds than the 2D model.However,the developing convective clouds of small areas at lower heights cannot be identified with the 3D model because they are covered by thick stratiform clouds.In addition,the 3D model can avoid the influence of the melting layer and better suggest convective clouds in the developmental stage.

Impact of diabetes mellitus and cardiometabolic syndrome on the risk of Alzheimer’s disease among postmenopausal women

BACKGROUND In spite of an increase in the incidence and prevalence of diabetes mellitus(DM)and Alzheimer’s disease(AD)in the aging population worldwide,limited attention has been paid to their potential association.AIM To investigate the association of DM and cardiometabolic syndrome(CMS,a precursor to DM)with risk of incident AD among postmenopausal women.METHODS Postmenopausal women aged 50-79(n=63117)who participated in the U.S.Women’s Health Initiative Observational Study(WHIOS),recruited in 1993-1998,without baseline AD and followed up through March 1,2019,were analyzed.AD was classified by participant-reported history of doctor-diagnosis of incident AD in the WHIOS.DM was defined by participant-report or treated because of diabetes or serum glucose concentrations≥126 mg/dL.CMS was defined as having≥3 of five CMS components:large waist circumference,high blood pressure,elevated triglycerides,elevated glucose,and low high-density lipoprotein cholesterol.The associations of DM and CMS with AD were analyzed using Cox’s proportional hazards regression analysis.RESULTS During a median follow-up of 20 years(range:3.36 to 23.36 years),of 63117 participants,8340 developed incident AD.Women with DM had significantly higher incidence of AD[8.5,95%confidence interval(CI):8.0-9.0 per 1000 personyears(PY)]than those without DM(7.1,95%CI:6.9-7.2 per 1000 PY).Multivariate Cox’s regression analysis indicated that women with DM or CMS had a significantly higher risk of AD than those without DM or CMS.The corresponding hazard ratios[HR(95%CI)]were 1.22(1.13-1.31,P<0.001)in subjects with DM,and 1.18(1.09-1.27,P<0.001)in subjects with CMS.The HRs diminished with age and became non-significant in the oldest age group.CONCLUSION During a median follow-up of 20 years,DM and CMS were significantly associated with the risk of AD among postmenopausal women.More specifically,women aged 50-69 with DM or CMS vs those without these conditions had significantly higher relative risks of AD than the relative risks of AD in those aged 70-79 with DM or CMS vs those without DM or CMS.

MIC17A is a novel diagnostic marker for feline toxoplasmosis

Toxoplasma gondii is a widespread parasitic pathogen that infect humans and all warm-blooded animals,causing abortion and stillbirth in pregnant women and animals,as well as life threatening toxoplasmosis in immune compromised individuals.Felines are the only defnitive hosts of Toxoplasma and oocysts shed by infected felines are the major source of infection for humans and other animals.Given the critical role of felines for T.gondii transmission,control of feline toxoplasmosis has signifcant impacts on reducing the overall prevalence of animal and human toxoplasmosis.However,reliable diagnosis of feline toxoplasmosis is still challenging.In this study,we found that the putative micronemal protein 17A(MIC17A)that was abundantly expressed in Toxoplasma merozoites is a good diagnostic marker for serological diagnosis of Toxoplasma infection in felines.T.gondii encodes four paralogs of MIC17A in total and the expression of three of them is drastically upregulated in merozoites than in tachyzoites.In contrast,when proteins like GRA1 and MIC3 that are more abundantly expressed in tachyzoites than in merozoites were used as diagnostic antigens to test feline toxoplasmosis,they reacted with Toxoplasma specifc IgG antibodies poorly.Taken together,these results suggest that merozoite antigens are better suited for the diagnosis of feline toxoplasmosis than antigens that are highly expressed at tachyzoite or bradyzoite stages.

蠼螋肠道中碱性内切葡聚糖酶基因的克隆表达及功能分析

【目的】从蠼螋肠道细菌菌株Q5中获得一个新型耐碱纤维素酶基因,通过异源表达、酶学性质及功能分析,旨在为以后进一步研究开发高温碱性纤维素酶提供一些理论参考。【方法】采用刚果红平板初筛法,从河南南阳宝天曼国家级自然保护区落叶堆下的昆虫蠼螋肠道中,获得具有分泌较高活性碱性纤维素酶的细菌菌株。基于该菌株的形态学、生理学及16S rRNA序列特征等对高活性菌株进行分类鉴定。并通过设计简并引物,从高活性菌株中克隆出该菌株的纤维素酶基因,并进行序列分析,并导入大肠杆菌BL21中表达。【结果】获得1株具有分泌较高活性碱性内切葡聚糖酶的细菌菌株Q5,经鉴定为甲基营养型芽孢杆菌,进一步从Q5菌株中成功克隆出该菌株的一个全长1500 bp的内切葡聚糖酶基因(GenBank KR067575),在NCBI比对后发现该基因的氨基酸序列与芽孢杆菌菌株LM 4-2的耐碱性β-1,4-内切葡聚糖酶基因(AKE23721.1)有98%的同源性。重组菌经优化培养,细胞破碎后上清液中的酶活力可达3.46 U/mL,是出发菌株Q5(2.05 U/mL)的1.69倍。经正交实验优化后的酶活力为4.99 U/mL。酶学性质研究表明:该酶的最适反应温度与pH值分别为50°C与pH 8.5,在pH 8.0和9.0保温48 h,其酶活力仍然维持到最高酶活的82%和81%;该酶在50°C以下较稳定,60°C以上酶活迅速降低。10 mmol/L的Ca^2+和Mg^2+对酶的活性有明显促进作用,重组酶Ega5的Km和Vmax分别是2.217 mol/mL和9.606μmol/(min·L)。该重组酶对棉花黄萎病病原菌大丽轮枝菌具有显著抑制作用。【结论】本文首次从蠼螋肠道中筛选到了一株产碱性内切葡聚糖酶的细菌菌株并从中克隆出了一个碱性纤维素酶基因,为该酶在碱性条件的应用奠定了理论基础。

The application of the Internet of Things to animal ecology

For ecologists,understanding the reaction of animals to environmental changes is critical.Using networked sensor technology to measure wildlife and environmental parameters can provide accurate,real-time and comprehensive data for monitoring,research and conservation of wildlife.This paper reviews:(i)conventional detection technology;(ii)concepts and applications of the Internet of Things(IoT)in animal ecology;and(iii)the advantages and disadvantages of IoT.The current theoretical limits of IoT in animal ecology are also discussed.Although IoT offers a new direction in animal ecological research,it still needs to be further explored and developed as a theoretical system and applied to the appropriate scientific frameworks for understanding animal ecology.

Heat Shock Protein 90.1 Plays a Role in Agrobacterium- Mediated Plant Transformation

Dear Editor, ManybacterialproteinsareinvolvedinAgrobacterium- mediated plant transformation. By contrast, relatively little is known about plant proteins that play key roles in transformation. Some of these host proteins interact with Virulence effector proteins, including VirE2, that are transferred from Agrobacterium to plants （Gelvin, 2010; Pitzschke and Hirt, 2010）. A recent study indicated that the plant protein SUPPRESSOR OF G2 ALLELE OF SKP1 （SGT1）, a co-chaperone of heat shock protein 90 （HSP90）, is required for Agrobacterium-mediated transformation （Anand et al., 2012）. These studies suggested the involvement of HSPg0 in Agrobacterium-mediated transformation.