170,361 research outputs found
An inverse modeling approach to obtain P-T conditions of metamorphic stages involving garnet growth and resorption
Get PDFThis contribution presents an approach and a computer program (GRTMOD) for numerical simulation of garnet evolution based on compositions of successive growth zones in natural samples. For each garnet growth stage, a new local effective bulk composition is optimized, allowing for resorption and/or fractionation of previously crystallized garnet. The successive minimizations are performed using the Nelder-Mead algorithm; a heuristic search method. An automated strategy including two optimization stages and one refinement stage is described and tested. This program is used to calculate pressure-temperature (P-T) conditions of crystal growth as archived in garnet from the Sesia Zone (Western Alps). The compositional variability of successive growth zones is characterized using standardized X-ray maps and the program XMapTools. The model suggests that Permian garnet cores crystallized under granulite-facies conditions at T>800 °C and P = 6 kbar. During Alpine times, a first garnet rim grew at eclogite-facies conditions (650 °C, 16 kbar) at the expense of the garnet core. A second rim was added at lower P (∼11 kbar) and 630 °C. In total, garnet resorption is modeled to amount to ∼9 vol% during the Alpine evolution; this value is supported by our observations in X-ray compositional maps
Thinking Race, Making Nation (reviewing Glenn C. Loury, The Anatomy of Racial Inequality)
Get PDFWe live in a race-conscious culture. As Americans, we are a nation of people who self-consciously chose to adopt a vision of society that embraced lofty ideals of individual freedom and democracy for all along with powerful mechanisms for devastating racial oppression. Our history is replete with instances of differential treatment on account of race - slavery being only the most egregious example - that achieved the desired effect of generating remarkable disparities in socioeconomic well-being among individuals and between different racial groups. Such disparities are not simply historical artifacts. They are facts of the contemporary American racial landscape as well. Racial disparity in socioeconomic well-being has always been, and continues to be, a central feature of American life. Of course, we each choose how we come to terms with racial inequality, how we rationalize, compartmentalize, or explain this phenomenon, and how we integrate our raced existence into our personal view of the world. For nearly three generations, we have undertaken a largely sustained collective effort to eliminate racial discrimination in American society. For some, the persistence of chronic racial inequality in the face of sustained efforts to ameliorate racial discrimination provides subtle confirmation of deeply held suspicions regarding the intellectual, cultural, or economic capacity of African Americans. For others, the persistence of racial disparity highlights the limits of the prevailing approach to antidiscrimination law and makes the case for greater intervention. Professor Glenn C. Loury\u27s The Anatomy of Racial Inequality is a thoroughgoing attempt to ascertain the root causes of racial inequality and provide insight into the thought process that causes us to view racial disparity with complacency and indifference. However, Loury\u27s project is not merely descriptive. His structural account of racial inequality provides the staging ground from which he launches a deep critique of prevailing views on American race relations. Racial inequity is not the product of some inherent deficiency in the minds and hearts of African Americans. Rather, it is a social pathology deeply rooted in American history - a pathology that evolved in tandem with American political and economic institutions, and with cultural practices that supported and legitimated those institutions . . . that were often deeply biased against blacks. Loury therefore rejects the conservative policy of indifference toward racial disparities, and declares emphatically that racial inequality is an American tragedy [and] a national, not merely a communal disgrace. In a very real sense, Loury\u27s free and extended meditation on racial inequality and the prospects of racial reform provides us with an insightful theoretical and discursive structure through which we can engage the struggle for racial justice anew. In this review essay, I offer an extended examination and critique of the major arguments presented in the book. In the course of connecting Loury\u27s work with historic and contemporary literature on racial disparities in American life, I offer some thoughts on the impact his project may have upon the shape of American race relations to come
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Affirmative Action and Its Mythology
Get PDFFor more than three decades, critics and supporters of affirmative action have fought for the moral high ground through ballot initiatives and lawsuits, in state legislatures, and in varied courts of public opinion. The goal of this paper is to show the clarifying power of economic reasoning to dispel some myths and misconceptions in the racial affirmative action debates. We enumerate seven commonly held (but mistaken) views one often encounters in the folklore about affirmative action (affirmative action may involve goals and timelines, but definitely not quotas, e.g.). Simple economic arguments reveal these seven views to be more myth than fact.
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Toward An Economic Theory of Dysfunctional Identity
Get PDFWe advance a novel choice-theoretic model of "identity" based on the notions of categories and narratives. Identity is conceived as a matter of "reflexive perception" -- how people understand themselves. Choosing an identity is equivalent to making a generalization about one's past that highlights the most salient aspects of experience. When many individuals make a common choice in this regard, they embrace a collective identity which is dysfunctional if it is Pareto dominated by an alternative self-classificatory schema. Using a simple multi-stage risk sharing game, we explore conditions under which dysfunctional collective identities might be expected to emerge.Identity; Dysfunctional Collective Identity
A 0.12mm<sup>2</sup> Wien-Bridge Temperature Sensor with 0.1°C (3σ) Inaccuracy from -40°C to 180°C
No full text Resistor-based temperature sensors can achieve much higher resolution and energy efficiency than conventional BJT-based sensors [1], but they typically occupy more area (> 0.25 mm 2 ) and have lower operating temperatures (le 125 {circ} {C}) [2]-[4]. This work describes a 0.12mm 2 resistor-based sensor that uses a Wien-bridge (WB) filter to achieve 0.1 {circ} {C} (3 sigma) inaccuracy from - 40 {circ} {C} to 180 {circ} {C}. Compared to a state-of-the-art WB sensor [4], it occupies 6 × less area and achieves comparable relative accuracy over a 76% wider operating range. Session 10.3 Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Electronic InstrumentationMicroelectronic
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