On the complete width and edge clique cover problems

A complete graph is the graph in which every two vertices are adjacent. For a graph \(G=(V,E)\), the complete width of G is the minimum k such that there exist k independent sets \(\mathtt {N}_i\subseteq V\), \(1\le i\le k\), such that the graph \(G'\) obtained from G by adding some new edges between certain vertices inside the sets \(\mathtt {N}_i\), \(1\le i\le k\), is a complete graph. The complete width problem is to decide whether the complete width of a given graph is at most k or not. In this paper we study the complete width problem. We show that the complete width problem is NP-complete on \(3K_2\)-free bipartite graphs and polynomially solvable on \(2K_2\)-free bipartite graphs and on \((2K_2,C_4)\)-free graphs. As a by-product, we obtain the following new results: the edge clique cover problem is NP-complete on \(\overline{3K_2}\)-free co-bipartite graphs and polynomially solvable on \(C_4\)-free co-bipartite graphs and on \((2K_2, C_4)\)-free graphs. We also give a characterization for k-probe complete graphs which implies that the complete width problem admits a kernel of at most \(2^k\) vertices. This provides another proof for the known fact that the edge clique cover problem admits a kernel of at most \(2^k\) vertices. Finally we determine all graphs of small complete width \(k\le 3\).     

领导者信息获取偏好对领导有效性的权变影响机制研究

通过227名中国企业中高层领导者样本,基于心理类型论和管理认知过滤机制理论,分析了领导者信息获取偏好通过变革型领导对领导有效性产生影响的内在作用机制,即领导行为的中介效应;同时,基于素质激活理论,揭示了状态不确定性对上述间接作用机制的有调节的中介效应。研究表明:变革型领导部分中介了领导者信息获取偏好对领导有效性的作用;状态不确定性对上述中介关系起到调节效应。此外,对研究结果的理论和实践意义进行了探讨,并指出了未来的研究方向。     

计算机辅助外语教学

计算机辅助教学可优化语言学习环境、充分利用教师资源,使互动式教学成为可能.语言教师要从思想概念上进行角色转换,在行动上作好准备,接受在线外语教学这一大趋势的挑战.     

El modelo de reactancia-indefensión de Wortman y Brehm desde la perspectiva de la psicofisiología social

Resumen

Este estudio fue diseñado para poner a prueba la hipótesis de reactancia-indefensión de Wortman y Brehm (según la cual los efectos producidos por la incontrolabilidad están mediados por la duración del evento incontrolable) en relación al funcionamiento corporal. Para ello, se eligió como principal variable dependiente el control de la respuesta electromiográfica de la musculatura frontal. Se utilizó un diseño factorial 3 (expectativa de control alta, baja y nula) X 2 (entrenamiento en incontrolabilidad corto y largo). Asimismo, se incluyeron medidas sobre «locus de control», estilo atribucional, percepción y estrategias de control. Los resultados obtenidos confirman parcialmente la hipótesis establecida y son discutidos dentro del ámbito de la Psicofisiologia Social.     

Age,religious beliefs,and sexual attitudes

Age effects on sexual attitudes were examined using the Hendrick and Hendrick (1987a) Sexual Attitude Scale. The study was cross‐sectional, including people from various age groups, from young adults to older adults. The religious beliefs variable, which covaries substantially both with age and sexual attitudes, was controlled. Three main questions guided the study: (a) Is the four‐factor structure (Permissiveness, Instrumentality, Communion, and Sexual Practices) previously identified in a sample of young students able to accurately account for data gathered over a full range of adult ages, (b) are older adults much less permissive and less instrumentalist than young people, and (c) to what extent are believers less permissive and instrumentalist than young people when age is taken into account? Factor analyses showed that at least five correlated factors were needed to account for the data; the fourth factor, Sexual Practices, divided itself into two distinct factors: Pleasure and Responsibility. Older adults and believers were shown to be less permissive than young people and nonbelievers, and this result held regardless of the participants’ educational level. As regards to instrumentality, however, the pattern of differences was extremely complex.     

HIV Risk Behaviors Among Three Classes of Female Sex Workers in Vietnam

Increases in the rate of HIV infection in Vietnam among female sex workers and their clients require more effective preventive interventions based on a better understanding of this population and important subgroups within it. Because little was known about women in the hospitality sex industry, this study compared demographic and work characteristics, history of sexually transmitted infections (STIs), and condom use among a sample of 310 female sex workers in low-, middle-, and high-class hospitality businesses in Ho Chi Minh City (mean age = 26.77 years, SD = 6.17). Data were collected through individual, face-to-face, semistructured interviews. Logistic regression models were used to identify demographic predictors of the incidence of STIs and reported condom use. Low occupational status was most strongly associated with a history of STIs, and use of condoms with new and regular clients also differed by occupational class. Implications are discussed.     

Vitebsk. The Life of Art

Deych, Genrich M., Putevoditel. Arkhivnye dokumenty po istorii evreev v Rossii v XlX‐nachale XXw. (A Research Guide to Materials on the History of Russian Jewry (Nineteenth and Early 20th Centuries) in Selected Archives of the Former Soviet Union.? Edited and introduced by Benjamin Nathans. (Moscow: Blagovest n.d., xii +149pp.)

Elyashevich, Dmitry A., compiler, Dokumentalnye materialy po istorii evreevv arkhivakh SNG i stran Baltii (Documentary Sources on Jewish History in the Archives of the CIS and the Baltic Countries) (St Petersburg: Acropolis 1994,134pp.)

Elyashevich, Dmitry A. and Kelner, Viktor, compilers, Literatura o evreyakh na russkom yazyke, 1890–1947: knigi, broshyury, ottiski statey, organy periodicheskoy pechati. Bibliografichesky ukazatel (Russian‐Language Literature on the Jews, 1890–1947: Books, Brochures, Reprints of Articles, Periodical Editions. Bibliographical Index) (St Petersburg: Humane Agency Academic Project 1995, 679pp.)

Freeze, Gregory L. and Mironenko, Sergey V. (eds.), Putevoditel. Tom I. Fondy Gosudarstvennogo arkhiva Rossiyskoy Federatsii po istorii Rossii XlX‐nachala XXw. (Research Guide. Volume I. Collections of the State Archive of the Russian Federation on the History of Russia in the Nineteenth and Early‐Twentieth Centuries) (Moscow: Blagovest 1994, xviii+394pp.)

Sallis, Dorit and Web, Marek (eds.), Jewish Documentary Sources in Russia, Ukraine and Belarus: A Preliminary List (New York: The Jewish Theological Seminary of America 1996, vii+164pp.)

Seriya ‘Evreysky arkhiv’. Obshchestvo ‘Evreyskoe nasledie’ (Jewish Archive Series, Jewish Legacy Society) (Moscow 1994)

Sobolev, V. S., editor and Anferteva, A. N., compiler. Gebraistika i istoriya evreyskoy kultury v Rossii. Tematichesky ukazatel dokumentov po fondam Sankt‐Peterburgskogo Arkhiva Rossiyskoy Akademii nauk (Hebraistics and the History of Jewish Culture in Russia. A Thematic Guide to Documents in the Collections of the St Petersburg Archive of the Russian Academy of Sciences). 2 volumes. (St Petersburg 1994–5, 42pp.+30pp.)     

"三全育人"理念下的《植物生长与环境》课程思政构建

为挖掘和融入《植物生长与环境》课程中的思政元素,落实课程在立德树人中的主渠道作用,该文以《植物生长与环境》教学设计为依托,挖掘每个知识点中蕴含的思政元素,融思想政治教育于专业课程教学中.在传授学生知识的同时引导学生树立远大志向,培养学生吃苦耐劳精神和创新精神,使之成为懂得感恩、德才兼备的栋梁之材,真正做到全员育人、全方位育人、全过程育人.     

Property testing for cyclic groups and beyond

This paper studies the problem of testing if an input (Γ,°), where Γ is a finite set of unknown size and ° is a binary operation over Γ given as an oracle, is close to a specified class of groups. Friedl et al. (Proc. of STOC, 2005) have constructed an efficient tester using poly(log|Γ|) queries for the class of abelian groups. We focus in this paper on subclasses of abelian groups, and show that these problems are much harder: Ω(|Γ|^1/6) queries are necessary to test if the input is close to a cyclic group, and Ω(|Γ| ^c ) queries for some constant c are necessary to test more generally if the input is close to an abelian group generated by k elements, for any fixed integer k≥1. We also show that knowledge of the size of the ground set Γ helps only for k=1, in which case we construct an efficient tester using poly(log|Γ|) queries; for any other value k≥2 the query complexity remains Ω(|Γ| ^c ). All our upper and lower bounds hold for both the edit distance and the Hamming distance. These are, to the best of our knowledge, the first nontrivial lower bounds for such group-theoretic problems in the property testing model and, in particular, they imply the first exponential separations between the classical and quantum query complexities of testing closeness to classes of groups.     

Functional outcomes and complications following B-TURP versus HoLEP for the treatment of benign prostatic hyperplasia: a review of the literature and Meta-analysis

Objective: To conduct a systematic review and Meta-analysis of the literature on the efficacy and safety of B-TURP versus HoLEP for the treatment of benign prostatic hyperplasia (BPH) in terms of demographic and clinical baseline characteristics, peri-operative variables, and postoperative outcomes and complications.

Methods: Trials comparing B-TURP and HoLEP were identified systematically using Pubmed, Embase, CNKI, Web of Science and the Cochrane Library. Primary outcomes were the peak urinary flow rate (Q_max), post-void residual volume (PVR) and international prostate symptom score (IPSS). Secondary outcomes were operation time, irrigation duration, catheterization duration, resected tissue and complications.

Results: Four trials assessing B-TURP and HoLEP were considered eligible for Meta-analysis, including three randomized controlled trials (RCTs) and one retrospective study. There was no statistically significant difference between B-TURP and HoLEP in terms of Q_max, IPSS, PVR at 3–6?months follow-up, operation duration, catheterization duration, resected tissue and complications (p?>?0.05). HoLEP was associated with a significantly shorter irrigation time as compared with B-TURP (p?Conclusion: Both B-TURP and HoLEP are safe and minimally invasive techniques that are similar in terms of symptomatic relief, although these findings need further validation in larger RCTs involving larger numbers of patients and over a longer follow-up duration for B-TURP or HoLEP before a new gold standard procedure emerges for surgical treatment of BPH.