11,750 research outputs found
No Evidence for a Aystematic FEII Emission Line Redshift in Type 1 AGN
We test the recent claim by Hu et al. (2008) that FeII emission in Type 1 AGN
shows a systematic redshift relative to the local source rest frame and
broad-line Hbeta. We compile high s/n median composites using SDSS spectra from
both the Hu et al. sample and our own sample of the 469 brightest DR5 spectra.
Our composites are generated in bins of FWHM Hbeta and FeII strength as defined
in our 4D Eigenvector 1 (4DE1) formalism. We find no evidence for a systematic
FeII redshift and consistency with previous assumptions that FeII shift and
width (FWHM) follow Hbeta shift and FWHM in virtually all sources. This result
is consistent with the hypothesis that FeII emission (quasi-ubiquitous in type
1 sources) arises from a broad-line region with geometry and kinematics the
same as that producing the Balmer lines.Comment: 12 pages, 1 table, 1 figure - accepted for publication in ApJ Letter
Iteratively Regularized Methods for Inverse Problems
We are examining iteratively regularized methods for solving nonlinear inverse problems. Of particular interest for these types of methods are application problems which are unstable. For these application problems, special methods of numerical analysis are necessary, since classical algorithms tend to be divergent
Resisting Commodification in Honors Education
The commodification of education is an increasing threat to university honors programs. In honors, we seek to unpack this transactional model of education and uncover the inherent joy of learning. Honors professionals can challenge the commodification of education by helping students contextualize their educational experiences and by facilitating joyful, self-directed learning. Framed by research of both gifted Kā12 students and college honors students, this article explores specific conversations and course designs that may combat a commodification culture and foster self-reflection and self-direction in honors students
How To Promote Self-Determination in Students with Disabilities
Self-determination is defined as āa combination of skills, knowledge, and beliefs that enable a person to engage in goal-directed, self-regulated, autonomous behavior. An understanding of one\u27s strengths and limitations together with a belief in oneself as capable and effective. When acting on the basis of these skills and attitudes, individuals have greater ability to take control of their lives and assume the role of successful adultsā (Denney & Daviso, 2012, pp. 43-44). A lack of self-determination can add to the problems of students with behavior concerns or disabilities. Many of them are on an Individual Education Plan (IEP) because their lack of self-determination is setting them back. They are falling behind not only academically, but socially and emotionally as well. The purpose of this literature review is to analyze what experts have studied about promoting self-determination in students with disabilities and their suggestions for future research. The goal of the research is to find ways to motivate children with disabilities. The principal finding from this literature review is that there are multiple aspects to promoting self-determination. While many authors and researchers have tried to standardize measurement and implementation of self-determination through various practices and perspectives including measurement tools, technology, supports of others, and through types of diversity, there is not a one-size-fits-all answer or solution. There will always be outliers. Self-determination on a broad scheme is a very complex issue that will need to be addressed systemically and individually
Teaching Map Concepts to Poor Readers
There is a concern that children with poor, i.e., below grade level reading ability, have trouble in content area subjects. The subjects of social studies, science, and health are often taught in the elementary grades through the use of textbooks. Because these texts prior to 1979 were written with a readability level at or above the grade level for which the book was designed, the poorer reader cannot read, and therefore learn, the subject matter presented.Children need knowledge of these content areas to function in today\u27s society. They also need the ability to read to increase their knowledge and to develop their interest in these areas. Our society also expects that certain aspects of social studies, science, and health will be taught to children. As teachers there is a responsibility to teach these objectives. The children are also graded and evaluated at the end of each school year in these subject areas. They I therefore I must acquire this knowledge to perform well on these tests. However, children with poor reading ability face difficulties acquiring this knowledge through a textbook oriented curriculum.The problem to be dealt with in this project is how to teach social studies to children with poor reading ability. The ojective is to aid these children in obtaining an understanding of specific social studies concepts. Few materials in the content area are available in Duval County for working with the reader who is below grade level.Specifically, this project will develop a curriculum of teaching techniques and materials to use with third-graders in the social studies area of map skills. This area was chosen because it is tested extensively on the third-grade Stanford Achievement Test. These materials will be used with a class of thirty third-grade students at Hyde Grove School in Duval County, Florida. These students are poor readers who read at least one grade level below their current grade in school, as measured by the Stanford Achievement Test reading section. The curriculum will attempt to facilitate map concept attainment for these children
Effects of Extreme Obliquity Variations on the Habitability of Exoplanets
We explore the impact of obliquity variations on planetary habitability in
hypothetical systems with high mutual inclination. We show that large
amplitude, high frequency obliquity oscillations on Earth-like exoplanets can
suppress the ice-albedo feedback, increasing the outer edge of the habitable
zone. We restrict our exploration to hypothetical systems consisting of a
solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We
verify that these systems are stable for years with N-body simulations,
and calculate the obliquity variations induced by the orbital evolution of the
Earth-mass planet and a torque from the host star. We run a simplified energy
balance model on the terrestrial planet to assess surface temperature and ice
coverage on the planet's surface, and we calculate differences in the outer
edge of the habitable zone for planets with rapid obliquity variations. For
each hypothetical system, we calculate the outer edge of habitability for two
conditions: 1) the full evolution of the planetary spin and orbit, and 2) the
eccentricity and obliquity fixed at their average values. We recover previous
results that higher values of fixed obliquity and eccentricity expand the
habitable zone, but also find that obliquity oscillations further expand
habitable orbits in all cases. Terrestrial planets near the outer edge of the
habitable zone may be more likely to support life in systems that induce rapid
obliquity oscillations as opposed to fixed-spin planets. Such planets may be
the easiest to directly characterize with space-borne telescopes.Comment: 46 pages, 12 Figures, 5 Table
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