Mathematical Analysis of West Nile Virus Model with Discrete Delays

The paper presents the basic model for the transmission dynamics of West Nile virus (WNV). The model, which consists of seven mutually-exclusive compartments representing the birds and vector dynamics, has a locally-asymptotically stable disease-free equilibrium whenever the associated reproduction number (?₀) is less than unity. As reveal in [3, 20], the analyses of the model show the existence of the phenomenon of backward bifurcation (where the stable disease-free equilibrium of the model co-exists with a stable endemic equilibrium when the reproduction number of the disease is less than unity). It is shown, that the backward bifurcation phenomenon can be removed by substituting the associated standard incidence function with a mass action incidence. Analysis of the reproduction number of the model shows that, the disease will persist, whenever ?₀ > 1, and increase in the length of incubation period can help reduce WNV burden in the community if a certain threshold quantities, denoted by Δ_b and Δ_v are negative. On the other hand, increasing the length of the incubation period increases disease burden if Δ_b > 0 and Δ_v > 0. Furthermore, it is shown that adding time delay to the corresponding autonomous model with standard incidence (considered in [2]) does not alter the qualitative dynamics of the autonomous system (with respect to the elimination or persistence of the disease).     

Erythrina alkaloids from leaves of Erythrina arborescens

Continued interest in Erythrina alkaloids resulted in the isolation of 38 alkaloids including 7 undescribed ones from the leaves of Erythrina arborescens Roxburgh. Among the new compounds, erythrivarines H-I were two dimeric alkaloids, while others were Erythrina alkaloid glucosides. Dimeric Erythrina alkaloids and monomers, turcomanidine and isoboldine, showed medium xanthine oxidase inhibition.     

长期精神紧张建立抑郁症模型

目的 采用长期精神紧张刺激建立动物抑郁症模型。方法 选用C57BL/6 J雄性4周龄小鼠17只,体质量(11. 05±1. 65) g,随机分为对照组、长期精神紧张刺激(LTMS)组。LTMS组单笼饲养并连续21 d每天给予猫惊吓3 h和剥夺睡眠12 h。实验组通过测定摄食量变化和高架十字迷宫实验、旷场实验、强迫游泳行为学变化来判断建模是否成功。结果 与对照组相比,LTMS组摄食量明显降低(P<0. 01),强迫游泳不动时间显著延长(P<0. 01)。旷场试验中,LTMS组小鼠穿越格数和直立次数均明显少于对照组,差异具有极显著性(P<0. 01)。高架十字迷宫实验中,LTMS组小鼠闭合臂停留时间明显延长,差异具有极显著性(P<0. 01);进入开臂次数比例减少,差异具有显著性(P<0. 05)。结论 长期精神紧张模型表现出行为绝望、活动能力下降、兴趣丧失、焦虑与抑郁症临床表现相似的症状,可作为抑郁症模型。     

江汉盐湖盆地油气形成与运聚特征

为厘清陆相盐湖盆地油气形成和运聚特征，以江汉盆地潜江凹陷潜江组为研究对象，通过岩芯分析的古生物、地球化学测试数据等，恢复盐湖古环境，分析盐湖沉积特征，厘定烃源岩发育及其演化特征，探讨油气排烃及运聚特征。研究结果表明，盐湖干湿交替周期变化的古气候，造成了湖盆咸淡交替，形成了碎屑岩、碳酸盐岩、蒸发岩有规律地韵律沉积，沉积岩性为成分复杂的混积岩；盐湖优质烃源岩发育在咸淡转化期，盐湖烃源岩演化相对滞后，发育未熟低熟油演化阶段；特殊的盐湖沉积特征导致了烃源岩排烃效率低，形成了规模巨大的烃源岩油藏；油气主要沿侧向运移，常规砂岩油藏具有顺层、近源、砂控、源控的特点。陆相盐湖盆地的沉积、油气形成与运聚特征与海相或淡水湖盆具有明显差异性，在勘探中应当引起重视。     

A review of recent advances in catalytic combustion of VOCs on perovskite-type catalysts

Along with the rapid development of industry, VOCs gradually move into the spotlight, and now become a kind of harmful environmental pollutants that cannot be overlooked. This paper introduces the hazards of VOCs and the common catalytic combustion catalysts, noble metal catalysts and non-noble metal catalysts, for the elimination of VOCs. Perovskite catalysts, as one of the non-noble catalysts, play an important role in the field of catalytic combustion in recent years. According to the classification of elements doping in perovskites, the research achievements in the past five years were analyzed and reviewed. In addition, this paper also analyzes and elaborates the reaction kinetics and QSAR/QSPR models for the introduction of structural properties and reaction mechanisms.     

KL油田沙三下亚段混合沉积特征及演化

针对目前莱州湾凹陷南斜坡带KL油田沙河街组三段下亚段陆源碎屑与碳酸盐岩混合沉积形成条件、沉积特征及模式认识程度较低的问题，利用该区壁芯、薄片及扫描电镜等资料，结合构造演化、古气候和古地貌背景，在层序格架约束下研究沉积环境，分析其沉积特征。结果表明，研究区发育混合沉积，形成于宽缓斜坡、亚热带湿润气候，兼具湖平面、物源、水动力条件周期性变化等条件；该混合沉积包括相缘渐变混合与原地混合两种沉积类型，互层式和组分式两种混合模式，以及4种混合样式。两种混合沉积类型沉积机理不同，混合模式及组合样式表现较大差异，因而具有不同的储层微观特征。     

The detection of cobalt by the microcosmic salt bead

I. The fact, that the blue violet colour of the microcosimic salt bead of cobalt is changed into blue by addition of Na₂CO₃ K₂CO₃, K₂CO₃ NA₂HPO₄ or NA₃PO₄is explained by the formation of pyrophosphate in the melt. II. K₂Na₂P₂O₇ if melted together with CoCl₂ forms blue porcelaneous masses, completely soluble in water.     

西部新建本科院校青年外语教师科研能力培养探究--基于广西某新建本科高校科研现状的个案调查

西部新建本科院校青年外语教师的科研能力相对薄弱,应结合学校实际情况加以培养和提高。青年外语教师应树立科研目标,完善知识结构;高校应做好科研定位,以教学带动科研,开展学术交流,加强科研培训,搭建人文社科网络学术交流平台,实行科研导师制,并健全科研激励机制和文科科研评价体系。     

鲁西隆起区奥陶系碳酸盐岩成岩环境演化

根据野外剖面观察和室内薄片鉴定,鲁西隆起区岩石类型主要为碳酸盐岩,包括白云岩、石灰岩及其过渡类型,其次为蒸发岩和膏溶角砾岩。研究区经历了多期次、多类型的成岩作用。储层储集空间主要包括晶间孔、粒间和粒内溶孔、残余粒内孔和粒间孔、铸模孔、溶洞和裂缝。结合研究区地质背景、岩石学特征和成岩作用分析,将该区成岩环境划分为海水成岩环境、表生成岩环境和埋藏成岩环境。其中:表生成岩环境中发育的溶蚀作用是优质储层形成的关键;海水成岩环境和中埋藏成岩环境中发育的白云石化作用对储层也起到了积极作用;而埋藏成岩环境中发育的胶结作用是造成储层物性变差的主要原因。     

高邮凹陷阜一段差异成岩作用及成因

高邮凹陷阜一段处于不同成岩阶段的储层出现了大致相同的成岩矿物的成岩现象,通过对目的层成岩阶段、成岩现象分析,结合构造、盆地流体等因素,提出差异成岩原理,认为当地层倾斜角度不大时,同一时代的地层往往处于相同的成岩阶段;早期成岩阶段的产物可能会在晚期成岩阶段中残留;当地层倾角较大时,同一时代的地层可能处于不同的成岩阶段,深部成岩流体的向上流动使浅部处于早期成岩阶段的储层具有晚期成岩现象.