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A manifold is a space that locally looks like the smooth space $\mathbf{R}^{n}$. It is usually also assumed that the underlying topological space of a manifold is hausdorff. However, there are natural examples of manifolds for which the hausdorff conditions fails. Some but not all of these examples contain bifurcate pairs of curves: pairs of curves that agree on some initial interval but disagree on a later interval. The first part of this note proves that a manifold $M$ is hausdorff if and only if (i) it contains no bifurcate curves and (ii) there is a hausdorff manifold $N$ with the same algebra of smooth real-valued functions as $M$; this confirms a conjecture of Wu and Weatherall. The second part of this note shows that a hausdorff manifold $N$ satisfying (ii) is a certain quotient of $M$., Comment: 11 pages, 0 figures

We describe a distributed processing cluster of inexpensive Linux machines developed jointly by the Astronomy and Computer Science departments at Haverford College which has been successfully used to search a large volume of data from a recent radio pulsar survey. Analysis of radio pulsar surveys requires significant computational resources to handle the demanding data storage and processing needs. One goal of this project was to explore issues encountered when processing a large amount of pulsar survey data with limited computational resources. This cluster, which was developed and activated in only a few weeks by supervised undergraduate summer research students, used existing decommissioned computers, the campus network, and a script-based, client-oriented, self-scheduled data distribution approach to process the data. This setup provided simplicity, efficiency, and "on-the-fly" scalability at low cost. The entire 570 GB data set from the pulsar survey was processed at Haverford over the course of a ten-week summer period using this cluster. We conclude that this cluster can serve as a useful computational model in cases where data processing must be carried out on a limited budget. We have also constructed a DVD archive of the raw survey data in order to investigate the feasibility of using DVD as an inexpensive and easily accessible raw data storage format for pulsar surveys. DVD-based storage has not been widely explored in the pulsar community, but it has several advantages. The DVD archive we have constructed is reliable, portable, inexpensive, and can be easily read by any standard modern machine., Comment: Adapted from a talk given at the Eleventh SIAM Conference on Parallel Computing, February 25-27, 2004 in San Francisco, CA. 18 pages, including 3 figures and 2 tables

Students considered at-risk are defined as students who lack a sense of identity, personal connectedness, and personal power. Another characteristic of at-risk students is the role parents play or fail to play in the at-risk behavior. A case is made for all students being at risk at some point in their lives. Four programs were designed and implemented to help at-risk and marginal students at one junior high school. The four programs include the OK Club, the Quest for Success Skills Program, the I-CANN (Individualized Course Alternative, Now or Never), and the Student Assistance Council. The OK Club is designed to build self-esteem and to provide after school-support and requires a strong parental component. The Quest for Success Skills Program is a transition program which prepares at risk sixth-graders for junior high school. The I-CANN Program provides counseling, development of self-esteem, and a hands-on curriculum. It also has a strong parental component. The Student Assistance Council involves a staff team that assesses the needs of at-risk students and recommends actions to address those needs. A successful program must begin with an attitude of caring. This caring attitude must be reflected by the total school staff toward every student and his or her family. (ABL)

This booklet examines four philosophical approaches which undergird the tenets of middle school: (1) invitational education; (2) democratic schools; (3) constructivist teaching; and (4) reflective teaching. An introduction discusses the history of the middle school movement, lists characteristics of exemplary middle schools, presents recommendations of the Carnegie Task Force for middle school operation, and summarizes the functions of middle schools. A chapter is devoted to each of the philosophical movements; in each chapter, the philosophy is defined, its major principles elucidated, and its implementation at the middle school level discussed. Invitational education involves working from a language that expresses care, reflected through modeling, dialogue, practice, and confirmation. The basis of democratic schools is to make a commitment to conditions and processes that make mutual respect and continuous dialogue possible for all participants. Constructivist teaching entails a belief that learning is a social process in which teachers help learners to internalize and reshape information or reinvent their knowledge. Reflective teaching requires teachers to think seriously about the origins and consequences of their pedagogy and about the situations and constraints embedded in the instructional, curricular, school, and social contexts in which they work. The four philosophical movements are complementary and provide a sound basis for educators to provide meaningful experiences for young adolescents. (Contains 43 references.) (Author/KDFB)