Existence of Two Limit Cycles in Zeeman’s Class 30 for 3D Lotka-Volterra Competitive System

Gyllenberg and Yan(Discrete Contin Dyn Syst Ser B 11(2):347–352,2009)presented a system in Zeeman’s class 30 of 3-dimensional Lotka-Volterra(3D LV)competitive systems to admit at least two limit cycles,one of which is generated by the Hopf bifurcation and the other is obtained by the Poincaré-Bendixson theorem.Yu et al.(J Math Anal Appl 436:521–555,2016,Sect.3.4)recalculated the first Liapunov coefficient of Gyllenberg and Yan’s system to be positive,rather than negative as in Gyllenberg and Yan(2009),and pointed out that the Poincaré-Bendixson theorem is not applicable for that system.Jiang et al.(J Differ Equ 284:183–218,2021,p.213)proposed an open question:“whether Zeeman’s class 30 can be rigorously proved to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem?”This paper provides four systems in Zeeman’s class 30 to admit at least two limit cycles by the Hopf theorem and the Poincaré-Bendixson theorem and gives an answer to the above question.

ClassⅡ细菌素乳酸菌的筛选与定性及群体感应系统鉴定

筛选具有Class Ⅱ细菌素群体感应系统广谱抑菌作用的乳酸菌并进行鉴定,为产Class Ⅱ细菌素乳酸菌的研究应用奠定基础。将排除过氧化氢和有机酸干扰作用的10株乳酸菌,经胰蛋白酶、胃蛋白酶和蛋白酶K处理,采用牛津杯法筛选具有分泌细菌素广谱抑菌效果的乳酸菌和最小抑菌实验检测其最小抑菌浓度,通过16S rDNA同源性分析构建系统发育树,设计合成乳杆菌Class Ⅱ细菌素5个操纵子plnEFI、plnJKLR、plnGHSTUV、plnABCD和plnMNOP的特异性引物,PCR和电泳鉴定L-4分泌Class Ⅱ细菌素基因群体感应系统,通过UPLC和尿素-SDS-PAGE确定细菌素的分子质量。L-4为可能具有广谱抑菌作用革兰氏阳性植物乳杆菌,它对指示菌产生的抑菌圈分别为(18.83±0.39)mm和(19.96±0.49)mm,最小抑菌浓度分别为55μg/mL和57μg/mL;L-4具有分泌Class Ⅱ细菌素群体感应基因系统,能够分泌分子质量为10 ku蛋白类细菌素且符合Class Ⅱ细菌素分子量大小范围。L-4是1株具广谱抑菌作用且能分泌10 ku Class Ⅱ细菌素的植物乳杆菌。

草药S抑制大鼠移植肾排斥反应中MHC Class Ⅱ分子表达的研究

为探索草药Ｓ抗大鼠同种异体肾移植急性排斥的作用机理，采用改进的Ｆａｂｒｅ和Ｋａ－ｍａｄａ大鼠原位肾移植模型，将ＳＤ大鼠肾移植给Ｗｉｓｔａｒ大鼠为同种异体移植，Ｗｉｓｔａｒ移植给Ｗｉｓｔａｒ大鼠为同品系移植（空白对照），共设五个实验组，观察移植后受体鼠存活、检测移植肾功能及定量测定移植肾内ＭＨＣＣｌａｓⅡ抗原分子的表达。结果表明，草药Ｓ能延长受体鼠存活时间，并抑制ＭＨＣＣｌａｓⅡ在移植肾内的表达（与不用药物组比较Ｐ＜０．０１），Ｓ药加小剂量环孢素Ａ（ｃｙｃｌｏｓｐｏｒｉｎｅＡ，ＣｓＡ）治疗组与同系组相比差异无显著性（Ｐ＞０．０５）。这些结果提示，移植肾内ＭＨＣＣｌａｓｓⅡ表达水平的高低与其排斥的强弱有相关性。

LEIBNIZ′FORMULA OF GENERALIZED DIFFERENCE WITH RESPECT TO A CLASS OF DIFFERENTIAL OPERATORS AND RECURRENCE FORMULA OF THEIR GREEN′S FUNCTION

In this paper, Leibniz' formula of generalized divided difference with respect to a class of differential operators whose basic sets of solutions have power form, is considered. The recurrence formula of Green function about the operators is also given.

On M–Term Approximations of the Nikol'skii–Besov Class in the Lorentz Spaces

In this paper, we consider a Lorentz space with a mixed norm of periodic functions of many variables. We obtain the exact estimation of the best M-term approximations of Nikol＇skii＇s and Besov＇s classes in the Lorentz space with the mixed norm.

On Approximation of Function Classes in Lorentz Spaces with Anisotropic Norm

In this paper, Lorentz space of functions of several variables and Besov＇s class are considered. We establish an exact approximation order of Besov＇s class by partial sums of Fourier＇s series for multiple trigonometric system.

A Gauss-Newton-Based Broyden’s Class Algorithm for Parameters of Regression Analysis

In this paper, a Gauss-Newton-based Broyden’s class method for parameters of regression problems is presented. The global convergence of this given method will be established under suitable conditions. Numerical results show that the proposed method is interesting.

Understanding the Effects of Various Factors on the Public Response to Congestion Charge: A Latent Class Modeling Approach

The standard ordered response model (SORM) is a common disaggregate approach with ordered outcomes in which the effects of various exogenous attributes are assumed constant across ordinal choices. In this study, an innovative latent class based generalized ordered response model (LC-GORM) is formulated and used to assess the effects of various factors on respondents’ choice behavior with respect to congestion charge proposal for Jakarta, Indonesia. The proposed model probabilistically assigns respondents into selfish and altruistic class memberships (latently) based on their knowledge of the proposed scheme and their specific attributes. Aiming to capture observable preference heterogeneity across ordinal choices and allow the thresholds to be varied across observations, we parameterize the thresholds as a linear function of the exogenous variables for each ordinal preference. Using stated preference data collected in Jakarta in December 2013, we incorporate the influence of a comprehensive set of explanatory variables into four categories: charges, latent variables related to respondent’s psychological motivations, mobility attributes and socio-demographic characteristics. Empirical results obviously verify the existence of preference heterogeneity across outcomes. The findings confirm that the altruistic class are more sensitive with respect to acceptance of the scheme, while the selfish class are more sensitive with respect to rejection. The key factors influencing public acceptability include the charge level and respondent variables such as car dependency, awareness of the problem of cars in society, frequency of visits to the city center and frequency of private mode usage.

PNY 8GB Class 4 SDHC存储卡容量大速度快

晕近必恩威（PNY）推出了一款特别的SDHC闪存卡新品——Class 4规格的SDHC卡。我们以前曾经介绍过，SDHC卡是SD卡的下一代产品，主要优势在于容量更大，分为Class 6、Class4和Class 2三种规格，要求写入速度分别达到6MB／s、4MB／s和2MB／s。

The Importance of Design Spectra and Site Class for the Design of High-Rise Buildings

On November 26,2019 a strong earthquake of magnitude M6.4 occurred close to the City of Durrës,Albania(15.6 km WSW(west southwest)of Mamurras and 22 km SSW(south southwest)of Durrës),causing fatalities and considerable damages in many buildings.In this article we present and analyze,by means of observational data and numerical simulation,the behavior under this earthquake of an 8-floor RC(reinforcement concrete)building,by using design spectra referring to KTP-N.2-89 and Eurocode 8.The main purpose of the authors is to better understand and evaluate the seismic performance of high-rise buildings under the design spectra with a period of soil oscillation close to the fundamental period of the structure.

A NEW CLASS OF LOCALLY CONVEX SPACES AND THE GENERALIZATION OF KALTON'S CLOSED GRAPH THEOREM

By introducing the notions of L-spaces and L_r-spaces, a complete generalization of Kalton's closed graph theorem is obtained. It points out the class of L_r-spaces is the maximal class of range spaces for the closed graph theorem when the class of domain spaces is the class of Mackey spaces with weakly * sequentially complete dual.Some examples are constructed showing that the class of L_r-spaces is strictly larger than the class of separable B_r-complete spaces.Some properties of L-spaces and L_r-spaces are discussed and the relations between B-complete (resp. B_r-complete) spaces and L-spaces (resp. L_r-spaces) are given.

Expression and Characterization of a Sigma-Class Glutathione S-transferase of the Oriental Migratory Locust, Locusta migratoria manilensis (Meyen)

A cDNA encoding a sigma-class glutathione S-transferase of the locust, Locusta migratoria manilensis （LmGSTs1）, was cloned by reverse transcriptase-polymerase chain reaction. The 830 bp-long cDNA encoded a 615 bp open reading frame （204 amino acid polypeptide）, which exhibited the structural motif and domain organization characteristic of GST sigma-class. It revealed 59, 57, 57, and 56% identities to sigma-class GSTs from Blattella germanica, Gryllotalpa orientalis, Nasonia vitripennis, and Pediculus humanus corporis, respectively. A recombinant protein （LmGSTs1） was functionally expressed in Escherichia coli cells in a soluble form and purified to homogeneity. LmGSTs1 was able to catalyze the biotranslation of glutathione with 1-chloro-2,4-dinitrobenzene, a model substrate for GSTs, as well as with p-nitro-benzyl chloride. Its optimal activity was observed at pH 8.0 and at 30℃. Incubation for 30 min at temperatures below 50℃ scarcely affected the activity. The I50 of reactive blue （RB） was 18.5 μmol L-1. In the presence of 0.05 mmol L-1 ethacrynic acid （ECA）, LmGSTs1 showed （81±3）% of the original activities.

Inner Mongolia builds up world's class wind power generation farm

The first phase project of Huitengxile Wind Power Generation Farm in Inner Mongolia, with nine 600 kW wind power generators installed, was formally put into commercial operation on November 28,

速度升级——松下Class 10 SDHC闪储卡

3 在各种下一代闪存卡的规格纷纷公布之后．作为SD卡技术领头羊的松下率先推出了Class 10 SDHC卡。相比之前的三种规格来说．数据大小差别似乎并不大，但读写速度却也因此提升至22MB／s。

Peasants and Alligators: A Love Story in China's Countryside

ＰｅａｓａｎｔｓａｎｄＡｌｌｉｇａｔｏｒｓ：ＡＬｏｖｅＳｔｏｒｙｉｎＣｈｉｎａ＇ｓＣｏｕｎｔｒｙｓｉｄｅ￥ＷＵＭＩＮＧ（ＩｎＹｉｎｊｉａｂｉａｎ，ａｓｍａｌｌｖｉｌｌａｇｅｏｎｔｈｅｌｏｗｅｒｒｅａｃｈｅｓｏｆｔｈｅＹａｎｇｔｚｅＲｉｖｅｒ，ｖｉｌｌ...

MERCEDES BENZ E CLASS 拳拳心“E”

毫无疑问,奔驰这次要动真格的!你可以说奔驰E级太像S级会拉低S级的尊贵感,但你不能否定E级的客户基数远大于S级,而S级在中国的销量甚至宝马7系和奥迪A8加起来也难以抗衡的事实。你可以说奔驰E级内饰毫无新意,完全是S级的翻版,但你不能否认,奔驰对豪华的理解和内饰的营造是同级别车企难以望其项背的事实。更何况,全新的9挡变速器、Apple carPlay以及Mercedes me强大的互联系统、全面升级的安全舒适装备,奔驰新E级已经武装到了牙齿,

The Literature Review of Teacher’s Feedback and Students’ Participation in Class

Teacher’s feedback has been studied by a large number of researchers by scholars from various angles.Along with teach⁃er’s feedback,students’participation in class,another vital topic concerning education,has also caught people’s attention in re⁃cent years.This paper is the literature review of teacher’s feedback and students’participation in class.The review of teacher’s feedback focuses on its definition,classification and function;and the literature review of students’participation in class centers around its definition,value and the method to improve students’participation in class.

Quantitative Analysis of the Sized Ranged Plastic Debris on Beach Shoreline along the Limbe Coastline, Cameroon

In recent years, increased interest in investigating the accumulation of sized ranged plastic debris has been observed on beaches along coastlines. The abundance and distribution of the 4M’s sized class plastic debris were quantitatively assessed on five sandy beaches, in Cameroon. Duplicates of 2 × 2 m (4 m2) quadrants were sampled in each beach/month with a total of 80 quadrants. Collected plastic samples were washed, sieved and dried. Particles of size, ≥2 mm, were sorted and measured using a 30 cm ruler, and converted to mm. Overall, 12,822 particles by number (530.59 g) with a mean abundance of 40.07 items/m2 (1.66 g/m2) plastic debris was recorded. ANOVA (p = 0.05) shows a linear relationship between the meso- and micro-sized classes with significantly higher abundance recorded in LDB sites. The highest abundance by weight was recorded in August and June numerically. 80% of the plastic particles were between the size range, of 5 - 20 mm by number and 6 - 100 mm by weight. Moreover, in all beaches micro-sized class plastics were dominated by number 42.40% with fragmented debris dominant, in number/weight, 54.86% (25.69%) while meso-sized class plastics were 29.28% dominated by weight, with fragmented debris type, the most prevalence in number and weight as 46.11% (26.18%). On average, color and shape fractions revealed, colored and irregularly shaped plastics were dominant with an abundance of 80.45 ± 18.17 items/m2 (2.58 ± 0.68 g/m2) and 47.24 ± 20.40 items/m2 (1.39 ± 0.66 g/m2). Finally, the 0.0001 g plastic debris was dominant with a concentration, of 33.68 ± 7.23 items/m2. The intense use of beaches for recreation and poor waste disposal has increased the potential for plastic contamination.

The Cradle of China's First Class Seafarers:Qingdao Ocean Shipping Mariners College——by Lin Jinhe,President of Qingdao Ocean Shipping Mariners College

Qingdao Ocean Shipping Mariners College is a College subordinate to China Ocean Shipping (Group) Company under the Ministry of Communications. In our college there are the Department of Marine Navigation,Department of Marine Engineering, Department of Shipping Management and Department of Foreign Languages, offering speciahies of Marine Navigation, Marine Engine Control, Marine Electrical Equipment Control, Marine Radio Communication, International Shipping Management and International Finance and Accounting. We have 3 types of education: the education of formal college schooling, the training for implementation of the 95 revised STCW Convention and the continuation education. Meanwhile we undertake different training of COSCO’s contracted seafarers overseas and other managerial per-