The effect of beam-driven return current instability on solar hard X-ray bursts

The problem of electrostatic wave generation by a return current driven by a small area electron beam during solar hard X-ray bursts is discussed. The marginal stability method is used to solve numerically the electron and ion heating equations for a prescribed beam current evolution. When ion-acoustic waves are considered, the method appears satisfactory and, following an initial phase of Coulomb resistivity in which T sub e/T sub i rise, predicts a rapid heating of substantial plasma volumes by anomalous ohmic dissipation. This hot plasma emits so much thermal bremsstrahlung that, contrary to previous expectations, the unstable beam-plasma system actually emits more hard X-rays than does the beam in the purely collisional thick target regime relevant to larger injection areas. Inclusion of ion-cyclotron waves results in ion-acoustic wave onset at lower T sub e/T sub i and a marginal stability treatment yields unphysical results

Towards the Green-Griffiths-Lang conjecture

The Green-Griffiths-Lang conjecture stipulates that for every projective variety X of general type over C, there exists a proper algebraic subvariety of X containing all non constant entire curves f : C $\rightarrow$ X. Using the formalism of directed varieties, we prove here that this assertion holds true in case X satisfies a strong general type condition that is related to a certain jet-semistability property of the tangent bundle TX . We then give a sufficient criterion for the Kobayashi hyperbolicity of an arbitrary directed variety (X,V). This work is dedicated to the memory of Professor Salah Baouendi.Comment: version 2 has been expanded and improved (15 pages

What Does the Research Teach Feminists about the Possibility of Organizational Change?

At the winter meeting of SWS [Sociologists for Women in Society] in 2019, Barbara [Risman] heard Julia [McQuillan] give her SWS Feminist Lecture and was totally fascinated. The U.S. National Science Foundation had been spending millions of dollars each year to promote gender transformation on college campuses, hoping to increase the participation of women in science, technology, engineering, and math (STEM) disciplines. What had we learned about the organizational policies that were changed to overcome gender bias? What interventions made the most change? What did not seem to make any difference? Julia presented data on 19 years (at the time) at her own school, where she had been a major player in the feminist change agenda. When she gave the Feminist Lecture, she also talked about the potential for valuable insights from the many feminist sociologists who were working on institutional change projects with and without ADVANCE funding. . . . This special issue shows that the insights from feminist sociological research are vital for attempts to create more equitable universities. We must change structures and policies. But we should also pay close attention to how those policies begin to change cultural logics, and how that cultural change can simmer undetected for years. And then those seeds planted with ADVANCE grants can produce fruit in new organizational policies years later

Sur le lemme de Brody

Brody's lemma is a basic tool in complex hyperbolicity. We present a version of it making more precise the localization of an entire curve coming from a diverging sequence of holomorphic discs. As a byproduct we characterize hyperbolicity in terms of an isoperimetric inequality

Exploration Life Support Technology Development for Lunar Missions

Exploration Life Support (ELS) is one of NASA's Exploration Technology Development Projects. ELS plans, coordinates and implements the development of new life support technologies for human exploration missions as outlined in NASA's Vision for Space Exploration. ELS technology development currently supports three major projects of the Constellation Program - the Orion Crew Exploration Vehicle (CEV), the Altair Lunar Lander and Lunar Surface Systems. ELS content includes Air Revitalization Systems (ARS), Water Recovery Systems (WRS), Waste Management Systems (WMS), Habitation Engineering, Systems Integration, Modeling and Analysis (SIMA), and Validation and Testing. The primary goal of the ELS project is to provide different technology options to Constellation which fill gaps or provide substantial improvements over the state-of-the-art in life support systems. Since the Constellation missions are so challenging, mass, power, and volume must be reduced from Space Shuttle and Space Station technologies. Systems engineering analysis also optimizes the overall architecture by considering all interfaces with the life support system and potential for reduction or reuse of resources. For long duration missions, technologies which aid in closure of air and water loops with increased reliability are essential as well as techniques to minimize or deal with waste. The ELS project utilizes in-house efforts at five NASA centers, aerospace industry contracts, Small Business Innovative Research contracts and other means to develop advanced life support technologies. Testing, analysis and reduced gravity flight experiments are also conducted at the NASA field centers. This paper gives a current status of technologies under development by ELS and relates them to the Constellation customers who will eventually use them

A Vision for Catholic Higher Education in the 21st Century: Reflecting on the Boston College Roundtable

The nucleus of any university is the intellectual life that unfolds among faculty and students. Inevitably, that intellectual life is shaped by the broader university context. Examining that process—in particular, its connection to a Catholic understanding of university mission—offers insight into pressing issues. For instance, what shifting social and academic conditions—both opportunities and challenges—set a context for campus conversations? How might Catholic institutions respond to these conditions? Can Catholic institutions provide a hospitable place for integrating faith and reason at the institutional and personal levels? Can the Catholic intellectual tradition serve as a constructive and creative lens for transforming Catholic higher education? And drawing on ideas that emerged during the Boston College Roundtable seminars, how might change occur

Baumgarten on Sensible Perfection

One of the most important concepts Baumgarten introduces in his Reflections on Poetry is the concept of sensible perfection. It is surprising that Baumgarten does not elaborate upon this concept in his Metaphysics, since it plays such an important role in the new science of aesthetics that he proposes at the end of the Reflections on Poetry and then further develops in the Aesthetics. This article considers the significance of the absence of sensible perfection from the Metaphysics and its implications for Baumgarten’s aesthetics, before turning to the use Meier and Kant make of Baumgarten’s concept. In the end, this article shows that Baumgarten did not abandon his conception of sensible perfection in the Metaphysics, though its influence declined significantly after Kant rejected the idea that sensibility and the understanding could be distinguished by the perfections of their cognition.info:eu-repo/semantics/publishedVersio

Beyond the Analytic of Finitude: Kant, Heidegger, Foucault

The editors of the French edition of Michel Foucault's Introduction to Kant's Anthropology claim that Foucault started rereading Kant through Nietzsche in 1952 and then began rereading Kant and Nietzsche through Heidegger in 1953. This claim has not received much attention in the scholarly literature, but its significance should not be underestimated. In this article, I assess the likelihood that the editor’s claim is true and show how Foucault’s introduction to Kant’s Anthropology and his comments about Kant in The Order of Things echo the concerns about finitude and subjectivity in Heidegger’s Kant and the Problem of Metaphysics. I then argue that Foucault's later preoccupation with Kant's essay An Answer to the Question: What is Enlightenment? should be regarded as an attempt to develop an alternative to the Heideggerian interpretation of Kant, and the preoccupation with finitude, that had played such an important role in Foucault’s earlier works

The Science of Aesthetics, the Critique of Taste, and the Philosophy of Art

Aesthetics is the part of contemporary academic philosophy that is concerned with art, beauty, criticism, and taste. As such, it must address metaphysical issues (distinguishing works of art from other kinds of things), epistemic problems (the experience of beauty, the standards of critical judgment), and questions of value (the difference between good and bad taste). This makes it difficult to present a coherent account of the subject matter of aesthetics. In this article, I argue that this difficulty is the result of ambiguities and contradictions that arose in disputes about the relationship between the science of aesthetics, the critique of taste, and the philosophy of art in German philosophy during the eighteenth and early nineteenth century. By reconstructing the history of these debates, I hope to shed new light on the origins of aesthetics as a discipline and to explain why its subject matter and status within philosophy are still so difficult to define