Graduation Rates, Student Goals, and Measuring Community College Effectiveness

The goal of this study is to determine the institutional characteristics that affect the success of community college students as measured by the individual student probability of completing a certificate or degree or transferring to a baccalaureate institution. While there is extensive research on the institutional determinants of educational outcomes for K-12 education and a growing literature on this topic for baccalaureate institutions, few researchers have attempted to address the issue for community colleges. Using individual level data from the National Education Longitudinal Study of 1988 (NELS:88) and institutional level data from the Integrated Postsecondary Education Data System (IPEDS), we address two methodological challenges associated with research on community college students: unobserved institutional effects and attendance at multiple institutions. The most consistent results across specifications are the negative relationship between individual success and larger institutional size, and the proportion of part-time faculty and minority students

Axonal Membranes and Their Domains: Assembly and Function of the Axon Initial Segment and Node of Ranvier

Neurons are highly specialized cells of the nervous system that receive, process and transmit electrical signals critical for normal brain function. Here, we review the intricate organization of axonal membrane domains that facilitate rapid action potential conduction underlying communication between complex neuronal circuits. Two critical excitable domains of vertebrate axons are the axon initial segment (AIS) and the nodes of Ranvier, which are characterized by the high concentrations of voltage-gated ion channels, cell adhesion molecules and specialized cytoskeletal networks. The AIS is located at the proximal region of the axon and serves as the site of action potential initiation, while nodes of Ranvier, gaps between adjacent myelin sheaths, allow rapid propagation of the action potential through saltatory conduction. The AIS and nodes of Ranvier are assembled by ankyrins, spectrins and their associated binding partners through the clustering of membrane proteins and connection to the underlying cytoskeleton network. Although the AIS and nodes of Ranvier share similar protein composition, their mechanisms of assembly are strikingly different. Here we will cover the mechanisms of formation and maintenance of these axonal excitable membrane domains, specifically highlighting the similarities and differences between them. We will also discuss recent advances in super resolution fluorescence imaging which have elucidated the arrangement of the submembranous axonal cytoskeleton revealing a surprising structural organization necessary to maintain axonal organization and function. Finally, human mutations in axonal domain components have been associated with a growing number of neurological disorders including severe cognitive dysfunction, epilepsy, autism, neurodegenerative diseases and psychiatric disorders. Overall, this review highlights the assembly, maintenance and function of axonal excitable domains, particularly the AIS and nodes of Ranvier, and how abnormalities in these processes may contribute to disease

Understanding of prognosis in non-metastatic prostate cancer: a randomised comparative study of clinician estimates measured against the PREDICT prostate prognostic model

Abstract: PREDICT Prostate is an individualised prognostic model that provides long-term survival estimates for men diagnosed with non-metastatic prostate cancer (www.prostate.predict.nhs.uk). In this study clinician estimates of survival were compared against model predictions and its potential value as a clinical tool was assessed. Prostate cancer (PCa) specialists were invited to participate in the study. 190 clinicians (63% urologists, 17% oncologists, 20% other) were randomised into two groups and shown 12 clinical vignettes through an online portal. Each group viewed opposing vignettes with clinical information alone, or alongside PREDICT Prostate estimates. 15-year clinician survival estimates were compared against model predictions and reported treatment recommendations with and without seeing PREDICT estimates were compared. 155 respondents (81.6%) reported counselling new PCa patients at least weekly. Clinician estimates of PCa-specific mortality exceeded PREDICT estimates in 10/12 vignettes. Their estimates for treatment survival benefit at 15 years were over-optimistic in every vignette, with mean clinician estimates more than 5-fold higher than PREDICT Prostate estimates. Concomitantly seeing PREDICT Prostate estimates led to significantly lower reported likelihoods of recommending radical treatment in 7/12 (58%) vignettes, particularly in older patients. These data suggest clinicians overestimate cancer-related mortality and radical treatment benefit. Using an individualised prognostic tool may help reduce overtreatment

On the conditional frazil ice instability in seawater

It has been suggested that the presence of frazil ice can lead to a conditional instability in seawater. Any frazil forming in the water column reduces the bulk density of a parcel of frazil-seawater mixture, causing it to rise. Due to the pressure-decrease in the freezing point, this causes more frazil to form, causing the parcel to accelerate, and so on. We use linear stability analysis and a non-hydrostatic ocean model to study this instability. We find that frazil ice growth caused by the rising of supercooled water is indeed able to generate a buoyancy-driven instability. Even in a gravitationally stable water column, the frazil ice mechanism can still generate convection. The instability does not operate in the presence of strong density stratification, high thermal driving (warm water), a small initial perturbation, high background mixing or the prevalence of large frazil ice crystals. In an unstable water column the instability is not necessarily expressed in frazil ice at all times; an initial frazil perturbation may melt and refreeze. Given a large enough initial perturbation this instability can allow significant ice growth. A model shows frazil ice growth in an Ice Shelf Water plume several kilometres from an ice shelf, under similar conditions to observations of frazil ice growth under sea ice. The presence of this instability could be a factor affecting the growth of sea ice near ice shelves, with implications for Antarctic bottom water formation

Using Longitudinal Data to Increase Community College Student Success: A Guide to Measuring Milestone and Momentum Point Attainment

Most community colleges and many state community college systems collect extensive data on individual students. Unfortunately, these data are often underutilized in efforts to improve outcomes for individual students and colleges. Community college systems and their constituent colleges have only recently come to realize the potential for using student unit record (SUR) data for more than reporting student enrollments and program graduates. By organizing these data into term-by-term student transcript records over several years and incorporating individual student demographic data, colleges and states can create a powerful resource for understanding patterns of student progression and achievement over time. Understanding how students actually progress through their college programs is essential in developing strategies and choosing appropriate interventions to improve student outcomes. The challenge is to build expertise and capacity in college and state agency research departments to transform raw SUR data into meaningful information of practical use for policymakers and practitioners. Longitudinal SUR data can be used to answer many important questions about student progression (see Jenkins and Ewell, forthcoming). This Research Tool presents a guide to using such data to measure milestone achievements and momentum point attainments of community college students. Milestones are measurable educational achievements that include both conventional terminal completions, such as earning a credential or transferring to a baccalaureate program, and intermediate outcomes, such as completing developmental education or adult basic skills requirements. Momentum points are measurable educational attainments, such as completing a college-level math course, that are empirically correlated with the completion of a milestone. Milestone and momentum point data help to illuminate patterns of student progression and achievement. This guide is intended to help researchers in colleges and state agencies to use longitudinal SUR data to create simple and meaningful statistics on student achievement. The model presented in this guide will enable researchers to use longitudinal SUR data to identify different student groups among first-time community college students, calculate rates of attainment of milestones and momentum points for each group, and identify barriers to success for each group. The information from such an analysis can be used to identify college practices and student behaviors that are associated with successful outcomes and inform the development of policies and practices that address barriers to achievement. By continuing to track the progress of students over time, colleges and state agencies can also measure their progress in promoting student advancement and success

The Effects of Institutional Factors on the Success of Community College Students

Community colleges are the gateway to higher education for many students who would otherwise have limited access to college, particularly those who are from low-income households or are ethnic minorities, first generation college students, or immigrants. Yet only about one-third of all community college students receives any degree or certificate even eight years after initial college enrollment. And credit accumulation and completion rates are even lower for minority and low-income students. Meanwhile, community college student outcomes, as measures of college effectiveness, are of increasing concern for institutional accountability. The Bush administration and many legislators in Congress would like to hold postsecondary institutions to higher standards of accountability, just as they have done with elementary and secondary schools. Institutional reporting requirements to the Department of Education now include data for graduation rates overall and broken out by gender and race/ethnicity. More than half of all states take into account the performance of public colleges when determining higher education appropriations

Beyond Student Right-to-Know Data: Factors That Can Explain Community College Graduation Rates

Policymakers, educators, and researchers recognize the importance of community colleges as open door institutions that provide a wide range of students with access to college. At the same time, competing demands for the state funds that would support community colleges have resulted in reduced public allocations and higher student tuition fees. Understandably, therefore, both state policymakers and parents are increasingly focused on the returns to their public or private investments in education, and the outcomes of community college attendance are now under greater scrutiny. To facilitate the evaluation of the colleges, there are now available data, through the Student Right-to-Know and Campus Security Act (1990), which amended the Higher Education Act, on every college’s graduation rate for fall semester cohorts of first-time, fulltime (FTFT) students in degree programs. This information is known as the Student Right-to-Know (SRK) data. A related public concern is how the outcomes of community college students can be improved. Therefore, attempts are now being made to clarify the way that specific students define success and to identify the college policies and practices that can promote success for all students. For some community college students, college completion, defined as earning a degree or certificate, is the appropriate measure of success. For other students, success is demonstrated by transferring to a baccalaureate institution. Still others are satisfied with completing courses that increase their knowledge or skill level in a particular area even though their educational experience is not considered successful as defined by traditional educational outcomes

Influence of dna repair on nonlinear dose-responses for mutation

Recent evidence has challenged the default assumption that all DNA-reactive alkylating agents exhibit a linear dose-response. Emerging evidence suggests that the model alkylating agents methyl- and ethylmethanesulfonate and methylnitrosourea (MNU) and ethylnitrosourea observe a nonlinear dose-response with a no observed genotoxic effect level (NOGEL). Follow-up mechanistic studies are essential to understand the mechanism of cellular tolerance and biological relevance of such NOGELs. MNU is one of the most mutagenic simple alkylators. Therefore, understanding the mechanism of mutation induction, following low-dose MNU treatment, sets precedence for weaker mutagenic alkylating agents. Here, we tested MNU at 10-fold lower concentrations than a previous study and report a NOGEL of 0.0075μg/ml (72.8nM) in human lymphoblastoid cells, quantified through the hypoxanthine (guanine) phosphoribosyltransferase assay (OECD 476). Mechanistic studies reveal that the NOGEL is dependent upon repair of O6-methylguanine (O6MeG) by the suicide enzyme O6MeG-DNA methyltransferase (MGMT). Inactivation of MGMT sensitizes cells to MNU-induced mutagenesis and shifts the NOGEL to the left on the dose axis. © The Author 2013. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved