Active Vibration Control of a Single Mass Rotor on Flexible Supports

This paper considers vibration control of a single mass flexible rotor on damped flexible supports with active feedback control. Both proportional and derivative feedback control are utilized. Free vibrations and unbalance response of the rotor-control system are determined. The effect of proportional control is to increase the critical speed of rotating machinery while the effect of derivative control is to reduce the amplitude of vibration. Generally larger ratios of support stiffness to shaft stiffness require larger values of control parameters to produce given amplitudes of vibration.     

Methodological Issues in Ethnic and Racial Identity Research With Ethnic Minority Populations: Theoretical Precision,Measurement Issues,and Research Designs

This article takes stock of research methods employed in the study of racial and ethnic identity with ethnic minority populations. The article is presented in three parts. The first section reviews theories, conceptualizations, and measurement of ethnic and racial identity (ERI) development. The second section reviews theories, conceptualizations, and measurement of ERI content. The final section reviews key methodological and analytic principles that are important to consider for both ERI development and content. The article concludes with suggestions for future research addressing key methodological limitations when studying ERI.     

Personal and situational factors influencing coaches’ perceptions ofstress

Abstract

Coaching has been recognised as a demanding occupation, associated with a range of stressors. The extent to which coaches perceive stress is likely to be influenced by various personal and situational factors. The purpose of this study was to identify coaches' levels of perceived stress and examine the personal and situational factors that may influence coaches' perceptions of stress. In total, 502 coaches working with university, college, Canada Games, and/or nationally identified athletes completed this study. Coaches completed an online survey, which included questions regarding demographics, work/job-related considerations, and aspects relating to their contract. Coaches also completed the Perceived Stress Scale (Cohen, Kamarck, & Mermelstein, 1983 Cohen, S., Kamarck, T. and Mermelstein, R. 1983. A global measure of perceived stress. Journal of Health and Social Behavior, 24: 385–396. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Overall coaches indicated slightly below average levels of perceived stress (M = 15.13 out of 40) compared with norm-values (Cohen & Janicki-Deverts, 2012 Cohen, S. and Janicki-Deverts, D. 2012. Who's stressed? Distributions of psychological stress in the United States in probability samples from 1983, 2006, and 2009. Journal of Applied Social Psychology, 42: 1320–1334. [Crossref], [Web of Science ®] , [Google Scholar]). Demographic factors, job-related characteristics, and certain aspects of their contract were associated with coaches' perceptions of stress. In particular, unclear expectations, long-working hours (>40), lack of agreed evaluation criteria, higher salaries, and a lack of social support were related to higher perceptions of stress. As such, the findings of the current study indicate that a reduction in perceived stress is likely to be achieved through a multifaceted approach that addresses multiple factors associated with coaching.     

Distributed leadership of school curriculum change: an integrative approach

Since its inception in 1999, the distributed leadership framework of Spillane, Halverson, and Diamond [2004. “Towards a Theory of Leadership Practice: A Distributed Perspective.” Journal of Curriculum Studies 36 (1): 3–34. doi:10.1080/0022027032000106726] has supported research into leadership and change in schools. Whilst the conceptual integrity of the framework is sound, research based upon its premises has attracted some criticism. The research has had a narrowed focus which has not generally reflected the inseparability of the elements of the framework and the situation within which leadership is enacted. In addition, it often fails to account for the complexity of critical elements of the environment such as micropolitics. This position paper proposes a reconfiguration of the distributed leadership framework as a research framework in response to this critique. The paper asserts that this new perspective that is presented is able to respond to the critique through an integrated approach that encompasses situation, social distribution and task enactment and which supports an integrated approach to research methodology. This adapted framework has the potential to more fully support research design that is actuality holistic and embedded in the context.     

Relations Among Parenting,Culture, and Prosocial Behaviors in U.S. Mexican Youth: An Integrative Socialization Approach

We examined the longitudinal relations among parental socialization practices—including acceptance or harsh parenting and ethnic socialization—ethnic identity, familism, and prosocial behaviors in a sample of U.S. Mexican youth. Participants included 462 U.S. Mexican adolescents (M_age at Wave 1 = 10.4 years old; 48.1% female), their mothers, and fathers at the 5th, 7th, 10th, and 12th grades. Results showed that maternal and paternal ethnic socialization predicted several forms of prosocial behaviors via ethnic identity and familism. Fathers’, but not mothers’, harsh parenting and acceptance had direct links to specific forms of prosocial behaviors. This study suggests the need for culturally informed theories that examine the reciprocal relations between two distinct domains of cultural socialization.     

Programmed achievement using a within-class control

College students operated under different contingencies in the same classroom. The Programmed Achievement (PA) condition required students to evidence criterion performance (100% mastery) on 12 Chapter quizzes. Failure to evidence mastery performance on any of the quizzes resulted in the loss of a letter grade off the final course grade. The control condition involved a more traditional college classroom structure where students took chapter quizzes with no requirement to evidence mastery. A third group of low achievement students, identified at midterm, operated under control conditions the first half of the semester and were subsequently shifted to the PA contingency the second half of the semester. The results revealed only a slight superiority for PA students over controls and both PA and Control students demonstrated significantly better performance when compared to that of low achievement students prior to midterm. However, following the PA shift these subjects evidenced performance equivalent to that of the other two groups. Procedural and theoretical implications of these data were discussed.     

Cognitive Theory and the Use of Computers in the Primary Classroom

Research investigating the role of computers in the primary classroom is closely linked to the body of knowledge concerned with theories of learning and child development. Research is presented as an attempt to provide scientifically supportable reasons why computers are effective in education. Having established a theoretical base for computer use in primary classrooms, this paper then examines the educational application of cognitive theory to classroom instruction.     

Imagining Democratic Futures for Public Universities: Educational Leadership Against Fatalism's Temptations

At current rates, almost all U.S. public universities could reach a point of zero state subsidy within the next fifty years. What is a public university without public funding? In this essay, Kathleen Knight Abowitz considers the future of public universities, drawing upon the analysis provided in John Dewey's Democracy and Education. Knight Abowitz conducts an initial institutional analysis through two broad prisms: that of the political landscape that authorizes universities as public institutions, and that of the present political–economic context of public education in general and public universities in particular. Dewey's conception of democratic education is then explored; his arguments regarding aims, experience, thinking, and social intelligence provide important tools for imagining the democratic futures of public universities today.