Tameness on the boundary and Ahlfors' measure conjecture

Let N be a complete hyperbolic 3-manifold that is an algebraic limit of geometrically finite hyperbolic 3-manifolds. We show N is homeomorphic to the interior of a compact 3-manifold, or tame, if one of the following conditions holds: (1) N has non-empty conformal boundary, (2) N is not homotopy equivalent to a compression body, or (3) N is a strong limit of geometrically finite manifolds. The first case proves Ahlfors' measure conjecture for Kleinian groups in the closure of the geometrically finite locus: given any algebraic limit G of geometrically finite Kleinian groups, the limit set of G is either of Lebesgue measure zero or all of the Riemann sphere. Thus, Ahlfors' conjecture is reduced to the density conjecture of Bers, Sullivan, and Thurston.Comment: New revised version, 22 pages. To appear, Publ. I.H.E.S. This version represents a fairly substantial reorganization of the logical structure of the pape

Late Weichselian and Holocene Glacimarine Sedimentation and Environments in Kejser Franz Josephs Fjord and On The Adjacent Continental Margin, East Greenland

The study outlines the glacimarine sedimentation patters and processes and environments in the Kejser Franz Josephs Fjord and on the adjacent continental margin of East Greenland during the Late Weichselian and Holocene. A variety of techniques are adpoted in this study in order to address the objectives outlined previously. The study is based on a suite of 8 cores from the, mid to outer region of Kejser Franz Josephs Fjord, and the continental shelf and slope. Core analyses included i) logging (core and x-radiographs), ii) determination of grain size distribution, iceberg rafted debris and physical properties (water content, porosity, grain density), iii) determination of stable oxygen and carbon isotopes, iv) radiocarbon dating, and v) calculation of sedimentation and accumulation rates. Additionaly, acoustic data is incorporated into the study to place the sediment cores within a regional context in terms of the sedimentation patterns and processed throughout the study area. The sedimentary record within the study dates back to the Late Weichselian glaciation. The record is confined to the continental slope and partly the continental shelf. The nature, extend and mechanisms of ice advance during the Late Weichselian glaciation could not be determined in this study. The upper continental slope is characterised by iceberg sedimentation with additional contribution from distal remnant of meltwater outflows escaping from East Greenland, sea ice rafting and pelagic settling. Mass wasting is recognised by the prescence of debris flows, which are derived from the rapid and unstable build-up of large volumes of glacigenic sediment. Mass wasting events are intermittent, vary from small scale to large scale., and are derived from local slope regions. The mid to lower continental slope are characterised by rain out and suspension settling punctuated by intermittent sediment gravity flows. Sea ice conditions during the Late Weichselian are extended resulting in reduced ventialtion of ocean surface waters and decreased exchange of CO$^{2}$ between the atmosphere and ocean. Sedimentation rates are high in response to the focusing of sedimentation on the continental margin as ice advances to the continental shelf. The onset of the Late Weichselian deglaciation is dated to occur after 15,250 yr BP. Degalciation is recognised by a rapid depletion of oxygen isotopes to very light values, indicating the massive discahrge of meltwater to the oceans in response to the decay of the Greenland Ice Sheet. The meltwater pulse culminated at 13,020 yr BP on the continental slope and sometime between 10,000 - 13,010 yr BP on the continental shelf. The subsequent stratification of ocean surface waters leads to the reduced ventilation of ocean surgace waters and decreased exchange of CO$^{2}$ between the atmosphere and ocean. The presence of significant volumes of iceberg rafted sediments on the continental shelf between 10,000 - 13,010 yr BP, and pre-13,010 yr BP indicates that mass ice loss from the Greenland Ice Sheet is through iceberg calving. The lower contintental slope between 13,020-15,250 yr BP is dominated by repetitive turbidity current activity derived from upper continental slope mass wasting, which reverts to more quiescent rain out and suspension settling after 13,020 yr BP. The exact nature of ice retreat could not be reconstructed in this study. The Younger Dryas Stadial is poorly represented in the sedimentary record of this study relating to low sedimentation rates and the low resolution of the sedimentary during this interval. Isotopic records indicate extended sea ice conditions over the contintental slope, resulting in reduced ventilation of ocean surface waters and decreased exchange of CO$^{2}$ between the atmosphere and ocean. The stillstand position of glacier ice during the Yonger Dryas is not well constrained in this study. The onset of the post Younger Dryas deglaciation occurs soon after 10,000 yr BP and is marked by a meltwater pulse that influences the fjord and inner continental shelf. The meltwater discharge culminated at 9,540 yr BP on the inner contintental shelf and sometime before 7,440 yr BP in the outer fjord. The meltwaters are produced from the final retreat of the glacier-ice of the Greenland Ice Sheet to present day positions. The presence of laminated mud facies and iceberg rafted debris (sandy mud diamicton and mud with dropstones) indicate that ice mass loss is through ablation and iceberg calving. The subsequent stratification of ocean surface waters leads to the reduced ventilation of ocean surface waters and decreased exchange of CO$^{2}$ between the atmosphere and ocean. Sedimentation and accumulation rates are high in reponse to deglaciation. Deglaciation sequences are recognised from the outer fjord and inner continental shelf, comprising laminated mud facies, diamicton facies, bioturbated mud facies representing increasingly ice distal settings as glacier-ice retreats into the fjord system. The Holocene is characterised by decreased sea ice conditions leading to increased ventilation of ocean/fjord surface waters and the increased exchange of CO$^{2}$ between the atmosphere and fjord/ocean. Sedimentation within the fjord margins into the deeper basins. Rain out and suspension settling also occurs and dominates sedimentation over bathymetric highs and also occurs with the fjord basins (accounts for the most recent sedimentation). Sedimentation across the continental shelf is prevented by the erosive action of the East Greenland Current. Sedimentation is pronounced within the inner continental slope as composed of rain out and suspension settling deposits with virtually no iceberg rafted debris related to its ice-distal setting

The Interplay Between Law School Rankings, Reputations, and Resource Allocation: Ways Rankings Mislead

Symposium: The Next Generation of Law School Rankings held April 15, 2005 at Indiana University School of Law-Bloomington

Cryosphere: Antarctic ice growth and retreat

Antarctic Ice Sheet change during the last glacial cycle is unclear. The timing of moraine development in the Ross basin suggests that the ice sheet reached maximum thickness under the warming temperatures of the last termination

Alamitos Gap: A Case Study Using the Trench Remixing and Deep Wall Method

The trench remixing and deep wall method (TRD) is a one-phase process for excavation and in situ mixing of a vertical barrier. While the TRD method was developed and has been widely employed in Japan for more than a decade, it has only recently been used in the United States. Since the TRD method mixes the entire depth of the vertical profile, this method can be used to construct a more homogeneous wall than other in situ methods. Using a large revolving chain and cutter bar, the TRD equipment simultaneously excavates and mixes in situ soils and added slurry resulting in a continuous soil mixed wall. The blend of slag, Portland cement and clay-water slurry is added as the excavation moves along the alignment of the barrier and produces continuous vertical mixing of in situ soils with the added blend. This paper presents a case study of the first TRD project in the United States involved the construction of closed cells to allow full evaluation of the method. This installation was part of a larger evaluation of the use of a vertical passive barrier to prevent the intrusion of salt water into fresh ground water aquifers in Southern California. The paper describes the site characterization, an extensive laboratory study conducted to investigate the appropriate mix design, field construction and post-construction testing. The case study shows the methodology used to develop design mixtures and presents information showing the successful completion of a barrier wall by the TRD method

Void-for-Vagueness—Judicial Response to Allegedly Vague Statutes—\u3ci\u3eState v. Zuanich\u3c/i\u3e, 92 Wn. 2d 61, 593 P.2d 1314 (1979)

In light of the problematic nature of the void-for-vagueness doctrine, this note argues that a defendant should never have standing to challenge a statute as unconstitutionally vague unless sufficient facts have been established to allow the court to review the statute in its actual application to the defendant. If, however, Washington courts insist upon reviewing a challenged statute on its face, they should be alert to the possibility that judicial review under the void-for-vagueness doctrine will become unduly expansive. This note suggests that courts can minimize potential abuse by carefully framing the constitutional issue and by appropriately construing the challenged statute