Point Mutation of Hoxd12 in Mice

Purpose: Genes of the HoxD cluster play a major role in vertebrate limb development, and changes that modify the Hoxd12 locus affect other genes also, suggesting that HoxD function is coordinated by a control mechanism involving multiple genes during limb morphogenesis. In this study, mutant phenotypes were produced by treatment of mice with chemical mutagen, N-ethyl-N-nitrosourea (ENU). We analyzed mutant mice exhibiting the specific microdactyly phenotype and examined the genes affected. Materials and Methods: We focused on phenotype characteristics including size, bone formation, and digit morphology of ENU-induced microdactyly mice. The expressions of several molecules were analyzed by genome-wide screening and quantitative real-time PCR to define the affected genes. Results: We report on limb phenotypes of an ENU-induced A-to-C mutation in the Hoxd12 gene, resulting in alanine-to-serine conversion. Microdactyly mice exhibited growth defects in the zeugopod and autopod, shortening of digits, a missing tip of digit I, limb growth affected, and dramatic increases in the expressions of Fgf4 and Lmx1b. However, the expression level of Shh was not changed Hoxd12 point mutated mice. Conclusion: These results suggest that point mutation rather than the entire deletion of Hoxd12, such as in knockout and transgenic mice, causes the abnormal limb phenotype in microdactyly mice. The precise nature of the spectrum of differences requires further investigation.link_to_subscribed_fulltex

Student Progression Through Developmental Sequences in Community Colleges

Developmental education is designed to provide students with weak academic skills the opportunity to strengthen those skills enough to prepare them for college-level coursework. The concept is simple enough—students who arrive unprepared for college are provided instruction to bring them up to an adequate level. But in practice, developmental education (or “remedial” education, we use these terms interchangeably) is complex and confusing. Experts do not agree on the meaning of being “college ready,” and policies governing assessment, placement, pedagogy, staffing, completion, and eligibility for enrollment in college-level, credit-bearing courses vary from state to state, college to college, and program to program. The developmental education process is confusing enough simply to describe, yet from the point of view of the student, especially one with very weak academic skills and little previous success in school, it may appear as a bewildering set of unanticipated obstacles involving several assessments, classes in more than one subject area, and sequences of courses requiring three or more semesters of study before the student (often a high school graduate) is judged prepared for college-level work

Lingerers in the Community College

Many community college students fail to graduate. Even among those students who enroll for a substantial period of time and who earn a significant number of college credits, many fail to complete an award. To improve completion rates in community colleges, administrators may want to focus attention on this group of students we call “lingerers.” Compared with other students, such as those who drop out early in their college careers, lingerers demonstrate persistence and a strong intention to complete a college program, yet they do not earn an award. This result is costly both for the students and the colleges they attend. In this analysis, we examine the following questions: What are the characteristics of lingerers in community college? How do their course-taking behaviors differ from those of students who complete an award? What prevents them from completing? Our analysis is based on extensive unit record data on cohorts of students at nine community colleges in three states. The data include information on student demographics, course enrollment and performance, credential completion, and transfer. We track students for up to five academic years. The data used in this analysis are from the 2005–06 first-time-in-college (FTIC) student cohort at these nine colleges. Credit students (i.e., those students who either placed into or enrolled in developmental education or those who either placed into or enrolled in college-level coursework) constituted 36 percent of the full FTIC sample. We limit our study to this subset of credit students in order to restrict our analysis to students who were mostly likely to earn an award or transfer to a four-year college. As a result, the full sample used in our analysis is 27,713 students. We define lingerers as students in the sample who completed 30 or more college-level semester credits and were still enrolled in the same community college in their fifth year but who had not yet earned a credential. About 9 percent of students in our sample were lingerers. We also make comparisons with “completers,” students who earned an associate degree at the community college within five years. About 6 percent of students in our sample were completers

New Evidence of Success for Community College Remedial English Students: Tracking the Outcomes of Students in the Accelerated Learning Program (ALP)

This paper presents the findings from a follow-up quantitative analysis of the Community College of Baltimore County’s Accelerated Learning Program (ALP). Our results suggest that among students who enroll in the highest level developmental writing course, participation in ALP is associated with substantially better outcomes in terms of English 101 completion and English 102 completion (college-level English courses), which corroborates the results of a similar analysis completed in 2010. These results were consistent, and in some cases, even stronger, when we used propensity score matching. Moreover, using a larger number of cohorts and tracking students over a longer period of time, we also found that ALP students were more likely to persist to the next year than non-ALP students. Specific subgroup analyses for earlier versus later cohorts, as well as for Black and low-income students, revealed relationships between ALP participation and student outcomes that were similar to those found in the larger sample, although ALP appeared to be more effective for White and high-income students on some outcomes. Finally, we compared college-ready students enrolled in ALP sections of English 101 with their counterparts in wholly college-ready sections, and found that those in ALP sections had equivalent performance within English 101 itself, but slightly lower subsequent college-level course enrollment and completion

Get with the Program: Accelerating Community College Students' Entry into and Completion of Programs of Study

Most students who enter higher education through a community college fail to earn a postsecondary credential. One reason for this that has not received enough attention is that many students do not enter a college-level program of study. Many new students arrive at community colleges without clear goals for college and careers. Community colleges offer a wide array of programs but typically provide little guidance to help students choose and successfully enter a program of study. Community college departments often do not closely monitor the progress of students who do enter their programs to ensure that they complete. This paper, originally released in April 2011, presents a simple method that community colleges can use to measure rates of program entry and completion using data on students' actual course-taking behaviors rather than declared major or intent. This method is used to track the progress and outcomes of first-time college students over five years using data from an anonymous sample of community colleges. The analysis shows that it is essential for students to enter a program of study as soon as possible. Students who do not enter a program within a year of enrollment are far less likely to ever enter a program and therefore less likely to earn a credential. The paper offers suggestions for ways community colleges can rethink their practices at key stages of students' engagement to substantially increase rates of program entry and completion

Timing of Concentration, Completion, and Exit in Community Colleges

To develop policies aimed at increasing student success and institutional effectiveness, it is useful for colleges to understand when students reach significant academic milestones, what students do if they exit college before completion, and whether the timing of these events differs among students with different levels of academic preparedness. Research suggests that students who reach important milestones early in their college careers are more likely than others to achieve their education goals (Edgecombe, 2011). And knowing when particular kinds of students reach academic milestones (or when they exit college without attaining a degree) can shed light on common patterns of student progression (Moore and Shulock, 2009). This report examines how the timing of important events in community college student progression— reaching program concentration by earning nine college-level credits in a single area of study, completing a program of study, and exiting college prior to program completion—differs by students who upon entry to college are deemed college ready or are referred to developmental education in either one, two, or three subject areas. It also examines the timing of additional post-exit education outcomes of students who leave their first college prior to program completion. Using five years of course-level transcript data on 14,617 first-time-in-college students who in the 2005-06 academic year enrolled in one of eight community colleges across three different states, this descriptive analysis identifies in which term students at various levels of college preparedness reached program concentration, earned a degree or certificate, or exited college without completing a program. Students who entered community college as college ready in math, reading, and writing (16 percent of students in the sample) are compared to students who were referred to developmental education in one (32 percent), two (21 percent), or all three (31 percent) of those subject areas

Get With the Program... and Finish It: Building Guided Pathways to Accelerate Student Completion

Most community colleges offer a wide array of programs. Yet they typically provide little guidance to help new students choose a program of study and develop a plan for completing it, despite the fact that many new students enroll without clear goals for college and careers. In prior research charting the educational pathways and outcomes of community college students, we found that students who enter a program of study in their first year are much more likely to complete a credential or transfer successfully than are students who do not enter a program until the second year or later. With so many choices available and without a clear roadmap or someone monitoring their progress, it is not surprising that many community college students indicate that they are confused and often frustrated navigating their way through college. In this paper, we describe efforts by a growing number of colleges and universities to redesign academic programs and support services to create “guided pathways” designed to increase the rate at which students enter and complete a program of study