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

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

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

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

Ursinus College Bulletin, Fall 1983

Rediscovering the roots of Ursinus • Pooling our alumni resources • Ursinus: One of the best deals in town • The non-traditional student: It\u27s never too late • All-American visit • Sendai scrapbook • Pennsylvania German archives have busy Fall • $13,000 grant given Ursinus • Additions to faculty, staff • Ursinus phonatics • New business • Fall-Winter sports schedule • Women national lacrosse champs • \u2783 Loyalty Fund hits 57% • Missing alumni • Do you remember? • Zacharias commemoration readied • Memorial fund • Kennedy collection • Thank-you notes • Department chairmen named • News notes • Evening School • Marriages • Births • Deathshttps://digitalcommons.ursinus.edu/new_bulletin/1036/thumbnail.jp

Effective algebraic degeneracy

We prove that any nonconstant entire holomorphic curve from the complex line C into a projective algebraic hypersurface X = X^n in P^{n+1}(C) of arbitrary dimension n (at least 2) must be algebraically degenerate provided X is generic if its degree d = deg(X) satisfies the effective lower bound: d larger than or equal to n^{{(n+1)}^{n+5}}

Vegetation communities and edaphic relationships along a typical coastal saltmarsh to woodland gradient in eastern Tasmania

Saltmarsh soils impose harsh selection pressures on vegetation resulting in characteristic plant communities. For our study of the effect of edaphic factors on vegetation we chose Long Point in Moulting Lagoon, Tasmania’s largest saltmarsh, which is dominated by a diverse assemblage of halophytic succulents and graminoids. Three transects were established to sample variations in vegetation along the gradient from saltmarsh to woodland. Soil samples were analysed for summer and winter moisture, pH, and electrical conductivity (EC); a mixed summer and winter sample from each point was analysed for soil organic matter (SOM) and carbon. Additionally, a particle size analysis was carried out on all summer samples. Aspects of soil characteristics were aligned to classified vegetation groups and elevation. Moisture, pH, EC, SOM and carbon were all negatively correlated with elevation; the saltmarsh zone displaying higher levels of all variables than those in the adjacent woodland zone. Clay content decreased and sand content increased from the marine margin of the saltmarsh zone to the woodland zone. Within the saltmarsh zone, soil moisture, EC and carbon had highest values in the low marsh area, with values decreasing towards the upper marsh area. This study deepens our understanding of the roles various edaphic factors play in the floristic composition of coastal saltmarshes