On the geometry of the smallest circle enclosing a finite set of points

A number of numerical codes have been written for the problem of finding the circle of smallest radius in the Euclidean plane that encloses a finite set P of points, but these do not give much insight into the geometry of this circle. We investigate geometric properties of the minimal circle that may be useful in the theoretical analysis of applications. We show that a circle C enclosing P is minimal if and only if it is rigid in the sense that it cannot be translated while still enclosing P. We show that the center of the minimal circle is in the convex hull of P. We use this rigidity result and an analysis of the case of three points to find sharp estimates on the diameter of the minimal circle in terms of the diameter of P.     

Care practice #3: continuous labor support

This updated edition of Care Practice Paper #3 presents the evidence for the benefits of continuous support in labor. The role of the doula is explained. Women are encouraged to plan for continuous support during labor and to consider including a woman experienced with childbirth among their labor support team.     

本期话题：多元语境中的话语场——文艺复兴时期关于亚里士多德《修辞学》的论争：传播理论的跨文化解读

本演讲探讨了欧洲早期艺复兴期间（大约1350—1700）为解读亚里士多德的（修辞学）中的论述所做出的努力,讨论了欧洲的注释在理解亚里士多德的（修辞学〉中所遇到的困难,关注了当时学意料之外的某些论争,并力图阐释引起这些论争的原因。作认为,人们力图阐释关于一种化的论述并力图从另一种化的需求和兴趣来解读这种论述的努力对中美两国具有重要意义,这些阐释所可能引发的结果也具有积极意义。作的这种解读对当今世界——对中国和“西方”国家富有更为广泛的意义——因为他在试图解读产生于一种化而被转译到另一种化的修辞学和传播学理论。作指出,在欧洲艺复兴时期,人们相信修辞学和社会很大程度上是一回事。修辞学能够使人们避免暴力、摆脱兽性,使许多不同人的思想统一起来,促成一种包容各种矛盾的和谐社会。修辞学使我们变得明。[第一段]     

Phonological processing and emergent literacy in younger and older preschool children

Phonological awareness, phonological memory, and phonological access to lexical storage play important roles in acquiring literacy. We examined the convergent, discriminant, and predictive validity of these phonological processing abilities (PPA) in 389 3-, 4-, and 5-year-old children. Confirmatory factor analysis supported the validity of each PPA as separate from general cognitive ability and separate from each other. Multigroup structural equation modeling (SEM) with mean structure demonstrated that older preschoolers have better developed latent PPA than younger preschoolers but that the structure of PPA is equivalent. RAN was found uniquely associated with letter knowledge and text discrimination in younger preschoolers, and PA was found uniquely associated with word reading skills in older preschoolers. Finally, general cognitive ability was only indirectly associated with emergent literacy via PPA. These results highlight the importance of PPA in the early literacy development of English-speaking preschool children.     

Fostering creative performance in art and design education via self-regulated learning

Instructional Science - There is a lack of research and practice focused on how to foster higher-order processing, such as creative performance, within higher education settings. To address this...     

Interventions supporting baccalaureate achievement of Latinx STEM students matriculating at 2-year institutions: A systematic review

Numerous national reports have identified the importance of significantly improving pathways that begin with Latinx students enrolling in 2-year institutions and ultimately completing baccalaureate degrees in STEM fields at 4-year institutions. Many programs using multiple interventions have been designed, implemented, and studied to achieve this goal. To synthesize what has been learned from studies of these programs, this article presents a systematic review of published studies of programs designed to support Latinx student success in 2-year institutions and successful transfer to 4-year institutions, particularly for STEM majors. A total of 49 quantitative, 9 qualitative, and 16 mixed-methods studies published as reports, articles, or dissertations since 1980 were identified that met the criteria for the review. Studies covered a wide range of interventions, including mentoring, counseling, advising, study groups, tutoring, scholarships, orientations, career services, undergraduate research, articulation agreements, and transfer programs. Individually, these studies report positive influences on student success outcomes, including 2- and 4-year graduation, transfer to a 4-year institution, retention, and success in individual courses. However, the number of qualifying studies was surprisingly small, considering the importance of improving success of Latinx students and the length of time during which the problem has been repeatedly emphasized. Few interventions have been undertaken from explicitly assets-based perspectives or theoretical frameworks. The lack of explicit frameworks underlying interventions—combined with a sole/primary focus on students—suggests many interventions were approached from a deficit-based perspective. Further, the study found no pattern of replication studies that might confirm effectiveness of potentially promising interventions. Based on our analysis of evaluations presented in the studies, it does not appear that the research community has developed agreed-upon methods to evaluate commonly agreed-upon outcomes. Finally, no intervention has been sufficiently supported that widespread implementation could be recommended.     

Assessing Marijuana Use,Anxiety, and Academic Performance Among College Students

This article examines the relationship between marijuana use and anxiety symptoms among college students, with a secondary focus on marijuana use and grade point average (GPA). A secondary analysis was conducted on data obtained from the American College Health Association–National College Health Assessment. Results indicated that marijuana use was negatively associated with GPA among students with current anxiety and no formal treatment. The relationships between these variables may be more complex than previously thought.     

Predicting University Students’ Academic Success and Major Using Random Forests

Research in Higher Education - In this article, a large data set containing every course taken by every undergraduate student in a major university in Canada over 10 years is analysed. Modern...     

Concurrent and predictive validity of the LET-II for average children

Memory tests, such as the Learning Efficiency Test-II (LET-II), have frequently been used to describe the memory characteristics of special populations such as persons with learning disabilities, brain damage, or Alzheimer's disease. Yet, few research studies have examined the memory characteristics of normally functioning children and compared these characteristics to their performance on ability tests or real-life achievement criteria. This study investigates the predictive and concurrent validities of the LET-II for performance on the Kuhlmann-Anderson Tests (K-A), class grades, and actual grade level functioning in reading and mathematics for third and fourth grade children of average intelligence. The LET-II memory factor scores correlated significantly with the K-A scores, class grades and actual grade level functioning in reading. The relevance of these findings for norm-referenced psychological tests, and in particular memory tests, in real-life settings is examined. © 1996 John Wiley & Sons, Inc.