1,143 research outputs found

    Analytic Examples, Measurement Models and Classical Limit of Quantum Backflow

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    We investigate the backflow effect in elementary quantum mechanics - the phenomenon in which a state consisting entirely of positive momenta may have negative current and the probability flows in the opposite direction to the momentum. We compute the current and flux for states consisting of superpositions of gaussian wave packets. These are experimentally realizable but the amount of backflow is small. Inspired by the numerical results of Penz et al (M.Penz, G.Gr\"ubl, S.Kreidl and P.Wagner, J.Phys. A39, 423 (2006)), we find two non-trivial wave functions whose current at any time may be computed analytically and which have periods of significant backflow, in one case with a backwards flux equal to about 70 percent of the maximum possible backflow, a dimensionless number cbm0.04c_{bm} \approx 0.04 , discovered by Bracken and Melloy (A.J.Bracken and G.F.Melloy, J.Phys. A27, 2197 (1994)). This number has the unusual property of being independent of \hbar (and also of all other parameters of the model), despite corresponding to an obviously quantum-mechanical effect, and we shed some light on this surprising property by considering the classical limit of backflow. We discuss some specific measurement models in which backflow may be identified in certain measurable probabilities.Comment: 33 pages, 14 figures. Minor revisions. Published versio

    The Late Quaternary geology of the Housatonic River basin in southwestern Massachusetts and adjacent Connecticut

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    Guidebook for field trips in western Massachusetts, northern Connecticut and adjacent areas of New York: 67th annual meeting October 10, 11, and 12, 1975: Trip B-7; C-

    Sedimentation in a proglacial lake: Glacial Lake Hitchcock

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    Guidebook for field trips in Connecticut and south central Massachusetts: New England Intercollegiate Geological Conference 74th annual meeting, University of Connecticut, Storrs Connecticut , October 2 and 3, 1982: Trip Q-

    Correlates of Homeless Episodes among Indigenous People

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    This study reports the correlates of homeless episodes among 873 Indigenous adults who are part of an ongoing longitudinal study on four reservations in the Northern Midwest and four Canadian First Nation reserves. Descriptive analyses depict differences between those who have and have not experienced an episode of homelessness in their lifetimes. Multivariate analyses assess factors associated with a history of homeless episodes at the time of their first interview. Results show that individuals with a history of homeless episodes had significantly more individual and family health, mental health, and substance abuse problems. Periods of homelessness also were associated with financial problems. Among the female caretakers who experienced episodes of homelessness over the course of the study, the majority had been homeless at least once prior to the start of the study and approximately one–fifth met criteria for lifetime alcohol dependence, drug abuse, or major depression. Family adversity during childhood was also common for women experiencing homelessness during the study

    Correlates of Homeless Episodes among Indigenous People

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    This study reports the correlates of homeless episodes among 873 Indigenous adults who are part of an ongoing longitudinal study on four reservations in the Northern Midwest and four Canadian First Nation reserves. Descriptive analyses depict differences between those who have and have not experienced an episode of homelessness in their lifetimes. Multivariate analyses assess factors associated with a history of homeless episodes at the time of their first interview. Results show that individuals with a history of homeless episodes had significantly more individual and family health, mental health, and substance abuse problems. Periods of homelessness also were associated with financial problems. Among the female caretakers who experienced episodes of homelessness over the course of the study, the majority had been homeless at least once prior to the start of the study and approximately one–fifth met criteria for lifetime alcohol dependence, drug abuse, or major depression. Family adversity during childhood was also common for women experiencing homelessness during the study

    Listening to Adolescent Heartsongs: Phenomenological Possibilities in Teaching Writing

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    ABSTRACT Title of Dissertation: LISTENING TO ADOLESCENT HEARTSONGS: PHENOMENOLOGICAL POSSIBILITIES IN TEACHING WRITING Mary Ann McKenzie Hartshorn Doctor of Philosophy, 2007 Dissertation directed by: Professor Francine Hultgren Department of Education Policy and Leadership College of Education University of Maryland This hermeneutic phenomenological inquiry, is called by the question: What is the lived experience of high school students who share something they have written from the heart? The metaphor of the human heart opens my understanding of the experiences of thirty-two students who write and share their writings in sophomore English class. My understanding of this experience deepens during after-school conversations with twelve of those students. Text, offering words for hermeneutic pondering, was compiled from conversations, journals, student writings and sharing activities. All voices were taped and transcribed to provide a visual remembrance of these lived experiences. The methodology underpinning this human science inquiry, is identified by Max van Manen (2003) as one that "involves description, interpretation, and self-reflective or critical analysis" (p. 4). Through my students' heartfelt words, I see them write their way to self-discovery. The importance of "lived space" (van Manen, 2002, p. 102) is brought forward, and lets me understand that students need to feel at "home" in school if they are to be successful. As we create a sacred space together, my students and I experience safety and freedom. In this space we find our "i-dentities" and hear our heartsongs. When sharing those songs, students announce their fears of failure, death and the swift passage of time; their memories; their longing for communication and disappointment in not connecting. We dwell together in the unique, sacredness of each other, opening a listening space where relationality "allows us to transcend ourselves" (p. 105). It is here that we celebrate more similarities than differences. The valued end of any class should include a place where students feel comfortable with themselves and others. Curriculum should be relevant to each student, providing an opportunity for self discovery and acceptance. Writing of a personal nature must be included across the curriculum so students learn to value themselves, fellow human beings, and the universe

    Factors associated with growth in daily smoking among Indigenous adolescents

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    North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group, yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10-13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder, were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker. © 2012 The Authors. Journal of Research on Adolescence © 2012 Society for Research on Adolescence

    Factors Associated with Growth in Daily Smoking among Indigenous Adolescents

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    North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10 to 13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker

    Factors Associated with Growth in Daily Smoking among Indigenous Adolescents

    Get PDF
    North American Indigenous adolescents smoke earlier, smoke more, and are more likely to become regular smokers as adults than youth from any other ethnic group yet we know very little about their early smoking trajectories. We use multilevel growth modeling across five waves of data from Indigenous adolescents (aged 10 to 13 years at Wave 1) to investigate factors associated with becoming a daily smoker. Several factors, including number of peers who smoked at Wave 1 and meeting diagnostic criteria for major depressive episode and conduct disorder were associated with early daily smoking. Only age and increases in the number of smoking peers were associated with increased odds of becoming a daily smoker
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