Boston College

About: Boston College is a education organization based out in Boston, Massachusetts, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 9749 authors who have published 25406 publications receiving 1105145 citations. The organization is also known as: BC.

Atomic-scale imaging of wall-by-wall breakdown and concurrent transport measurements in multiwall carbon nanotubes.

Abstract: We report the atomic-scale imaging with concurrent transport measurements of the breakdown of individual multiwall carbon nanotubes inside a transmission electron microscope equipped with a piezomanipulator. We found unexpectedly three distinct breakdown sequences: namely, from the outermost wall inward, from the innermost wall outward, and alternatively between the innermost and the outmost walls. Remarkably, a significant amount of current drop was observed when an innermost wall is broken, proving unambiguously that every wall is conducting. Moreover, the breakdown of each wall in any sequence initiates in the middle of the nanotube, not at the contact, proving that the transport is not ballistic.

Impact of sudden stratospheric warmings on equatorial ionization anomaly

Abstract: [1] We investigate the ionospheric response to several stratospheric sudden warming events which occurred in Northern Hemisphere winters of 2008 and 2009 during solar minimum conditions. We use GPS total electron content data in a broad latitudinal region at ±40° geographic latitude and a single longitude, 75°W. In all cases, we find a strong daytime ionospheric response to stratospheric sudden warmings. This response is characterized by a semidiurnal character, large amplitude, and persistence of perturbations for up to 3 weeks after the peak in high-latitude stratospheric temperatures. The ionospheric perturbations at the lower latitudes usually begin a few days after the peak in stratospheric temperature and are observed as an enhancement of the equatorial ionization anomaly (EIA) in the morning sector and a suppression of the EIA in the afternoon sector. There is also evidence of a secondary enhancement in the postsunset hours. Once observed in the low latitudes, the phase of semidiurnal perturbations progressively shifts to later local times in subsequent days. This progressive shift occurs at a different rate for different stratospheric warming events. The large magnitude and persistence of ionospheric perturbations, together with the predictability of stratospheric sudden warmings several days in advance, present an opportunity to investigate these phenomena in a systematic manner which may eventually lead to a multiday forecast of low-latitude ionosphere conditions.

Treatment of Compulsive Behavior by Covert Sensitization

Abstract: Behavior therapy has achieved some success in the treatment of homosexuality, obesity, alcoholism and other compulsions. Here-tofore the aversive stimulus has been externally applied in the presence of the pleasurable but undesirable stimulus (or its substitute; e.g., words and pictures). In the method of covert sensitization the subject is asked to visualize the pleasurable stimulus while at the same time he is given instructions to imagine an unpleasant sensation such as vomiting. The method of covert sensitization is described, and two cases are presented illustrating its use.

The Problem of Teacher Education

Abstract: Since the time teacher education emerged as an identifiable activity, there have been few periods when it was not being critiqued, studied, rethought, reformed, and, often, excoriated. The title of this editorial does not refer to the "problem of teacher education" in a pejorative sense, however. Rather, the phrase is intended to draw attention to teacher education as a problem in three senses--the problem or challenge every nation faces in providing well-prepared and effective teachers for its children; teacher education as a research problem, which involves a larger set of educational issues, questions, and conditions that define an important concern of the scholarly community; and teacher education as a problematic and contested enterprise, troubled by enduring and value-laden questions about the purposes and goals of education in a democratic society. This editorial concentrates on teacher education over the last 50 years. It suggests that during that time, as a society and an educational community, we have conceptualized and defined the "problem of teacher education" in three quite different ways: as a training problem, a learning problem, and a policy problem. (1) The editorial concludes with concerns about the current emphasis. TEACHER EDUCATION AS A TRAINING PROBLEM During the period from roughly the late 1950s to the early 1980s, teacher education was defined primarily as a training problem. The essence of this approach was conceptualizing teacher education as a formal educational process intended to ensure that the behaviors of prospective teachers matched those of "effective" teachers. To do this, teacher educators were charged with training teacher candidates to display those behaviors that had been empirically certified through research on effective teaching. Underlying this way of defining teacher education was a technical view of teaching, a behavioral view of learning, and an understanding of science as the solution to educational problems. In a symposium on teacher education that helped to shape this emerging view, B. O. Smith (1971) made this clear: "Generally speaking, ... teacher education attempts to answer the question of how the behavior of an individual in preparation for teaching can be made to conform to acceptable patterns" (p. 2). What was "acceptable" had to do with research. When teacher education was constructed as a training problem, the point of research on teacher education was the identification or the invention of transportable teacher-training procedures that produced the desired behaviors in prospective teachers. This effort in teacher education built on and paralleled the process-product research on teaching that was dominant during the time. With process-product research, the goal was to develop "the scientific basis of the art of teaching" (Gage, 1978) by identifying and specifying teacher behaviors that were correlated with pupil learning and applying them as treatments to classroom situations (Gage, 1963). The version of this that became prominent in research on teacher education was treating the independent variables of process-product research on teaching (i.e., observable teacher behaviors, such as question-asking strategies or clearly stated objectives, which were presumed correlated with Student achievement) as the dependent variables in research on teacher preparation. Teacher-training procedures (e.g., microteaching, training prospective teachers to use interaction analysis or behavior modification, lecture, demonstration, and/or clusters of these procedures with and without different kinds of feedback) were the independent variables. The training approach to teacher education was not without its critics. Some questioned the training approach at its very core by critiquing the effectiveness research on which it was based. They argued that the empirical research base for specific and generally applicable teaching behaviors was thin and that the competency-based, teacher-training programs that arose in the late 1960s and early 1970s did not have a greater amount of empirical support than other teacher education programs. …

Stayers, leavers, lovers, and dreamers: insights about teacher retention

Abstract: Teacher shortages are not new. Periodically, throughout the past half century, there have been fewer teachers available than were needed, and policy makers at the state and federal levels have responded by stepping up recruitment efforts and issuing temporary teaching credentials to those without qualifications. Three things are new, however: the requirement that teachers in all schools be "highly qualified"; the realization that it is not so much teacher recruitment that is the problem in staffing the nation's K-12 schools but teacher retention; and growing evidence that, similar to every other problem that plagues the nation's schools, the problem of teacher retention is most severe in hard-to-staff schools. In 1999, in an article in Education Week, John Merrow reported that recruitment was both the "wrong diagnosis" and a "phony cure" (p. 38) for the teacher shortage. By 2003, the National Commission on Teaching & America's Future (NCTAF) had announced that teacher retention was a "national crisis" (p. 21). Drawing heavily on Richard Ingersoll's (2001, 2002) analyses of retention and attrition patterns in K-12 schools and on other analyses of large-scale state and national data sets, the NCTAF (2003) report concluded that the teacher shortage was caused primarily by early attrition of those in the teaching pool rather than by insufficient numbers of people preparing to teach. The report also made it clear that the retention problem was most severe in urban and rural schools where there were large numbers of poor and minority students. This editorial highlights five new analyses of teacher retention, which frame the problem in conceptually and methodologically different ways. (1) Due to space constraints, the editorial does not critique the five studies or offer extensive analysis that cuts across them, although this kind of analysis is needed. Rather, the purpose of the editorial is to highlight important insights about retention from each of the five pieces and invite readers to review each of them thoroughly. It's Retention, Not Recruitment: The Need for "Demand-Side" Analyses and Solutions Throughout the past decade, Richard Ingersoll (2001, 2002, 2003, 2004) has conducted a series of studies about the teacher workforce from the perspective of the sociology of organizations, occupations, and work. In many of these studies, Ingersoll uses data from the Schools and Staffing Survey (SASS) and its Teacher Follow Up Survey (TFS) to look at patterns and trends in the supply and demand of teachers for the nation's K-12 schools. Ingersoll's analyses challenge the conventional wisdom that the teacher shortage in the United States is due to a simple imbalance between supply and demand caused by large numbers of teacher retirements, increased student enrollments, and an insufficient supply of new teachers. Instead, Ingersoll reveals that it is true that both student enrollments and teacher retirements have increased since the mid-1980s, that most schools now have job openings, and that a significant number of schools have been unable to find enough qualified teachers. However, it is not true that most teachers who leave teaching do so because of retirement, and it also is not true that an insufficient number of teachers is being produced. To the contrary, Ingersoll (2004) argues that although there are not necessarily enough teachers produced in every field, there are overall, "more than enough prospective teachers produced each year in the U.S." (p. 8). Ingersoll argues that the crux of the retention problem is the teacher turnover rate, that is, the number of teachers per year who move from one teaching job to another or leave teaching altogether. As Ingersoll (2004) points out, the sheer size of the teaching force coupled with its annual turnover rate (about 14%) means that almost one third of the teacher workforce (more than one million teachers) move into, out of, or between schools in any given year. …