Evidence for J and H-band excess in classical T Tauri stars and the implications for disk structure and estimated ages

We argue that classical T Tauri stars (cTTs) possess significant non- photospheric excess in the J and H bands. We first show that normalizing the spectral energy distributions (SEDs) of cTTs to the J-band leads to a poor fit of the optical fluxes, while normalizing the SEDs to the Ic-band produces a better fit to the optical bands and in many cases reveals the presence of a considerable excess at J and H. NIR spectroscopic veiling measurements from the literature support this result. We find that J and H-band excesses correlate well with the K-band excess, and that the J-K and H-K colors of the excess emission are consistent with that of a black body at the dust sublimation temperature (~ 1500-2000 K). We propose that this near-IR excess originates at a hot inner rim, analogous to those suggested to explain the near-IR bump in the SEDs of Herbig Ae/Be stars. To test our hypothesis, we use the model presented by Dullemond et al. (2001) to fit the photometry data between 0.5 um and 24 um of 10 cTTs associated with the Chamaeleon II molecular cloud. The models that best fit the data are those where the inner radius of the disk is larger than expected for a rim in thermal equilibrium with the photospheric radiation field alone. In particular, we find that large inner rims are necessary to account for the mid infrared fluxes (3.6-8.0 um) obtained by the Spitzer Space Telescope. Finally, we argue that deriving the stellar luminosities of cTTs by making bolometric corrections to the J-band fluxes systematically overestimates these luminosities. The overestimated luminosities translate into underestimated ages when the stars are placed in the H-R diagram. Thus, the results presented herein have important implications for the dissipation timescale of inner accretion disks.Comment: 45 pages, 13 figure

Full Financial Aid in the Ivy League: How High-Achieving, Low-Income Undergraduates Negotiate the Elite College Environment

Thesis advisor: Karen ArnoldCurrently, there are nearly a million high-achieving, low-income students in the United States. In the nation's most selective institutions of higher education, students from low-income families have been persistently under-represented. Elite colleges, in particular, have only recently begun admitting low-income students in large numbers, a result of full need-based financial aid programs that began in the early 2000s as a way to attract a more socioeconomically diverse student body. This hermeneutic phenomenological study describes the lived experiences of these undergraduates and how they navigated a college environment historically reserved for wealthy students. Although participants initially expected to feel marginalized due to unfounded concerns of elitism, they formed friendships both within and across socioeconomic class divisions and described feeling integrated within the elite college. Participants developed self-protective narratives to compensate for their low-income backgrounds and employed strategies to make up for poor high-school preparation. Participants were grateful for the opportunity to attend an elite college and were proud and relatively forthcoming about their financial aid status because they considered it a reward for their intellectual ability. Three main conclusions derive from the findings of this research: Low-income students' tendency to make a distinction between socioeconomic and financial aid status; the notion of a new cultural capital hierarchy for high-achieving, low-income students within an elite college setting; and, a specific application of Bronfenbrenner's ecological developmental model for this niche population. The results of this study indicate that high-achieving, low-income students are flourishing in full need-based financial aid programs as a result of their own resilience and intellectual capital. Participants' experiences indicate that this population of undergraduates faces unique challenges and requires specific support services to equalize their opportunities vis-à-vis higher-income peers. From these findings, implications for colleges and universities and full need-based financial aid programs are discussed.Thesis (PhD) — Boston College, 2011.Submitted to: Boston College. Lynch School of Education.Discipline: Educational Administration and Higher Education

Academic Major, Gender, Personal Values, And Reactions To An Ethical Dilemma

Recent corporate scandals have increased public interest in the area of business ethics.  This study examines the relationship of gender and choice of academic major to personal values and to ethical choices, and the relationship of personal values to ethical choices.  Two hundred fifty three subjects read a case that presented a tax evasion dilemma.  The subjects responded to a series of action statements related to the ethical dilemma and completed a personal values survey.  The responses to the action statements were used to calculate a tax compliance score.  Participants were also asked to make a choice as to whether the taxpayer should or should not report all of the taxable income.  The results indicate that both the tax compliance score and the tax payment choice differed by gender and academic major.  Furthermore, gender differences were found on five of the ten personal value constructs and academic major differences were found on four of the ten personal value constructs.  With regard to the relationship of personal values to ethical choices, it was found that three of the personal value constructs were correlated with the compliance score and the tax payment decision

1987 Update of Agronomic Performance of Tall Fescue Varieties

Tall fescue (Festuca arundinacea, Schreb.) is a well adapted, widely used pasture species occupying approximately 5.5 million acres in Kentucky and 35 million acres in the south central United States. Commercial tall fescue varieties have been developed from plant materials of either northern European or Mediterranean origin. Varieties developed at the University of Kentucky -- Kentucky 31, Kenmont, Kenwell, Kenhy, and Johnstone -- trace to plant materials of northern European origin. The Kentucky varieties have later maturity dates and have greater resistance to certain foliar diseases during summer than varieties that are of Mediterranean origin (i.e., Alta, Fawn, Goar, and AU-Triumph) when grown under environmental conditions and management regimes prevailing in Kentucky. Varieties of Mediterranean origin have excellent ear1y spring and late fall growth when foliar diseases are not a problem. Foliar diseases, however, may cause them to be of inferior quality and to make poor growth during the summer. Generally, in Kentucky, tall fescue is used for hay and for pasture in spring, summer and fall. Agronomic research data indicate that varieties of northern European origin are superior to varieties of Mediterranean origin for forage purposes in Kentucky

Oral Advocacy Before the United States Supreme Court: Does It Affect the Justices\u27 Decisions?

Our empirical investigation focuses on two areas. First, we are interested in the quality of the oral advocacy presented to the Court, especially in terms of its etiology, as well as its effectiveness. We investigate these questions empirically by utilizing notes taken by Blackmun during oral arguments while he sat on the Court. Specifically, we here utilize the grades that Justice Blackmun assigned to each attorney’s oral arguments. This information allows us to answer two related questions: (1) why do some attorneys make better arguments before the Court; and (2) does the quality of oral advocacy influence who wins and loses? Second, we turn our attention to the information the Justices elicit about themselves during oral arguments. We analyze data on how often Justice Blackmun paid attention to the views expressed by his brethren during oral arguments (by examining when and why he recorded the comments of a particular colleague during orals) and the factors that led him to pay attention to some, but not all, of his colleagues. Additionally, we utilize Blackmun’s notes to demonstrate that what transpired during oral arguments provided him with an indication of whether his colleagues would vote to affirm or reverse the lower court decision at issue. We do so through an examination of when Justice Blackmun attempted to predict the votes of his colleagues in his oral argument notes. The Article proceeds as follows. In the next two Parts, we take up our first set of questions, which focuses on whether experienced and resourceful attorneys provide better arguments and whether arguments presented by counsel can affect decisions Justices make. Part IV focuses on whether Justices attempt to learn about their colleagues during oral arguments and whether such information affects the coalition-formation process that follows the arguments. Finally, we analyze whether what transpires during oral arguments can help a Justice make predictions about how a case will ultimately be decided

Think-Pair-Share as a Springboard for Study Buddies in a Virtual Environment

Many powerful teaching techniques have not yet fully transitioned from face-to-face use to the new remote instructional paradigm forced on teacher educators and teacher candidates during the pandemic. Experiences by candidates and by instructors in this new environment need to be compiled and shared as we head forward into structures and situations. This article describes how one such technique, Think-Pair-Share (Lyman, 1981) inspired assigning Study Buddies in a co-taught graduate level teacher education course, Managing Culturally Responsive Classrooms, in the summer of 2020. Two teacher candidates, two professors and Dr. Frank Lyman, offer insight and suggestions about this practice, its possibilities and its limitations as the course moved from a traditional implementation to a virtual setting

Herschel Observations of the T Cha Transition Disk: Constraining the Outer Disk Properties

T Cha is a nearby (d similar to 100 pc) transition disk known to have an optically thin gap separating optically thick inner and outer disk components. Huelamo et al. recently reported the presence of a low-mass object candidate within the gap of the T Cha disk, giving credence to the suspected planetary origin of this gap. Here we present the Herschel photometry (70, 160, 250, 350, and 500 mu m) of T Cha from the "Dust, Ice, and Gas in Time" Key Program, which bridges the wavelength range between existing Spitzer and millimeter data and provide important constraints on the outer disk properties of this extraordinary system. We model the entire optical to millimeter wavelength spectral energy distribution (SED) of T Cha (19 data points between 0.36 and 3300 mu m without any major gaps in wavelength coverage). T Cha shows a steep spectral slope in the far-IR, which we find clearly favors models with outer disks containing little or no dust beyond similar to 40 AU. The full SED can be modeled equally well with either an outer disk that is very compact (only a few AU wide) or a much larger one that has a very steep surface density profile. That is, T Cha's outer disk seems to be either very small or very tenuous. Both scenarios suggest a highly unusual outer disk and have important but different implications for the nature of T Cha. Spatially resolved images are needed to distinguish between the two scenarios.DIGIT Herschel Open Time Key ProgramNASAAlexander von Humboldt FoundationEuropean CommissionAgence Nationale pour la Recherche of France PERG06-GA-2009-256513, ANR-07-BLAN-0221, ANR-2010-JCJC-0504-01CNRS/INSU, FranceAstronom

Simulated Tractor Chassis Suspension System

The development of a chassis suspension system for an agricultural tractor has been described to improve the operator ride comfort. Computer simulation tech-niques were used to formulate the tractor models and to compute the natural frequencies and frequency response of the models, as well as the RMS acceleration response, to evaluate the effect of the suspension system and cab position on operator ride comfort