586 research outputs found
Classification of the line-soliton solutions of KPII
In the previous papers (notably, Y. Kodama, J. Phys. A 37, 11169-11190
(2004), and G. Biondini and S. Chakravarty, J. Math. Phys. 47 033514 (2006)),
we found a large variety of line-soliton solutions of the
Kadomtsev-Petviashvili II (KPII) equation. The line-soliton solutions are
solitary waves which decay exponentially in -plane except along certain
rays. In this paper, we show that those solutions are classified by asymptotic
information of the solution as . Our study then unravels some
interesting relations between the line-soliton classification scheme and
classical results in the theory of permutations.Comment: 30 page
ASPECTS OF THE MICROPALAEONTOLOGY AND STRATIGRAPHY OF CRETACEOUS SHELF CARBONATES FROM THE OMAN MOUNTAINS
Five outcrop sections (Wadi Mi'aidin, Wadi Bani Kharus, Jebel Madar, Jebel Madamar and Jebel Salak),
exposing Thamama and Wasia Group sediments were sedimentologically logged and sampled. Thin sections of
each of the Thamama Group samples were prepared for micropalaeontological and microfacies analysis. The
foraminifera, calcareous algae and calpionellids in each sample were recorded in order to provide a means of
biostratigraphic subdivision, and together with microfacies analysis and sedimentological observations made in
the field, provide a means of elucidating the depositional environments of the Thamama Group in the study
area. Correlation between outcrop sections has been attempted using a biozonation scheme developed in the
course of this project, and also by graphic correlation techniques. The taxonomy of 39 genera including 56
species of key foraminifera, calcareous algae and calpionellids is reviewed in detail.
A complete revision of Cretaceous Middle Eastern lithostratigraphic nomenclature is required. Some
recommendations for such a revision are proposed.
Within the Thamama Group, 13 biozones/subzones are recognised using the extinction and inception events for
key taxa. Both biozonal correlation and graphic correlation demonstrate that most Thamama Group formations
are diachronous and may also be condensed at some localities. Biostratigraphic studies demonstrate that in the
Central Oman Mountains region the Thamama Group formations are of the following ages: The Rayda
Formation is of Early Berriasian age. It possibly extends into the earliest Valanginian at some localities (eg.
Wadi Bani Kharus). The Salil Formation is of Berriasian - Valanginian age, possibly Hauterivian in age in its
upper part at some localities. The Habshan Formation is of Hauterivian age everywhere, with possible extension
into the Late Valanginian in its IOWCT part The Lekhwair Formation is essentially of Hauterivian - Barremian
age (often largely Hauterivian). The Kharaib Formation is of typically Late Barremian - Early Aptian age,
whilst the Shuaiba Formation is of Early Aptian age.
Thamama Group deposition took place on an initially downwarped carbonate ramp, prograding towards the
Tethyan Ocean (towards the north and east). Offshore palaeowinds precluded the development of reefs, but an
oolitic shoal was located at the margin of the ramp, at least during Hauterivian times.Earth Sciences Resources Institute at University College of Wales, Swansea and University of South Carolina,
USA and
AMOCO Petroleum Company Limited, Houston, US
An Italian dinosaur LagerstÀtte reveals the tempo and mode of hadrosauriform body size evolution
During the latest Cretaceous, the European Archipelago was characterized by highly fragmented landmasses hosting putative dwarfed, insular dinosaurs, claimed as fossil evidence of the âisland ruleâ. The Villaggio del Pescatore quarry (north-eastern Italy) stands as the most informative locality within the palaeo-Mediterranean region and represents the first, multi-individual Konservat-LagerstĂ€tte type dinosaur-bearing locality in Italy. The site is here critically re-evaluated as early Campanian in age, thus preceding the final fragmentation stages of the European Archipelago, including all other European localities preserving hypothesized dwarfed taxa. New skeletal remains allowed osteohistological analyses on the hadrosauroid
Tethyshadros insularis
indicating subadult features in the type specimen whereas a second, herein newly described, larger individual is likely somatically mature. A phylogenetic comparative framework places the body-size of
T. insularis
in range with other non-hadrosaurid Eurasian hadrosauroids, rejecting any significant evolutionary trend towards miniaturisation in this clade, confuting its âpygmyâ status, and providing unmatched data to infer environmentally-driven body-size trends in Mesozoic dinosaurs
A Study of Form and Structure in Pierre Boulez\u27s Pli selon Pli
In his 1963 treatise, Penser la musique aujourdâhui, Pierre Boulez proposes that there should be no distinction between serial materials and large-scale form. After his self-professed failure with Structures 1a and Polyphonie X due to the incapacity of the twelve-tone series to provide form in and of itself, Boulez reassessed and expanded his compositional approach to include what he refers to as âindiscipline,â which permitted him a new freedom to modify his materials as he saw fit through a plethora of new techniques, and to link these materials to large-scale forms that take their inspiration largely from literary influences. This investigation seeks to concretize Boulezâs proposed relationship between serial content and large-scale form in âDonâ (1962) and âTombeauâ (1959), the framing movements of Pli selon Pli, largely by establishing the nature of their formal organization and the origin of the serial materials used in their construction. The course of this investigation traces the developmental history of materials used in âDonâ and âTombeauâ which includes analyses of materials used in the unpublished Oubli signal lapidĂ© (1952), the retracted drama LâOrestie (1954â55), the unpublished work for solo flute Strophes (1955â56), the TroisiĂšme Sonate (1955â57), Le Marteau sans maĂźtre (1953-55) and the inner movements of Pli selon Pli: the âImprovisation[s] sur MallarmĂ© I, II, and IIIâ (1957, 1957, and 1959 respectively). The materials developed for âDonâ and âTombeauâ are largely continuations of different lineages of serial materials developed for these earlier works and form constellations of structurally related materials that persist beyond the boundaries of individual works. Taken together, the works composed during the period 1952â62 are the most inspired and creative in Boulezâs compositional history. The trajectory of this investigation incrementally introduces the reader to increasingly larger-scale means of organizing serial materials that culminate in Boulezâs evolving theory of discontinuous musical form. Connections among works and their organizational structure are largely derived from sketch studies undertaken at the Paul Sacher Foundation in Basel, Switzerland
-Schur functions and affine Schubert calculus
This book is an exposition of the current state of research of affine
Schubert calculus and -Schur functions. This text is based on a series of
lectures given at a workshop titled "Affine Schubert Calculus" that took place
in July 2010 at the Fields Institute in Toronto, Ontario. The story of this
research is told in three parts: 1. Primer on -Schur Functions 2. Stanley
symmetric functions and Peterson algebras 3. Affine Schubert calculusComment: 213 pages; conference website:
http://www.fields.utoronto.ca/programs/scientific/10-11/schubert/, updates
and corrections since v1. This material is based upon work supported by the
National Science Foundation under Grant No. DMS-065264
Preservation of Proterozoic Microbial Mats
Meso- to Neoproterozoic peritidal carbonate strata commonly contain early diagenetic chert deposits that can record evidence of mineral and organic precursors. Exceptional morphologic preservation can be used to place time constraints on silicification, often indicating silicification is penecontemporaneous with mat growth. Silica-rich sedimentary deposits have also been suggested as potential targets for the search for extraterrestrial life on Mars. The chapters in this dissertation investigate fluid compositions capable of precipitating primary and secondary silica phases and the extent to which microorganisms are preserved, specifically their morphology and chemistry, by early silicification. Twenty potential fluid compositions were modeled using PHREEQC, and the mineral phases capable of precipitating were compared to the mineralogies observed in thin sections from silicified microbial mats of the Angmaat Formation, Bylot Supergroup. This model indicates that silica phases were capable of precipitating as primary or secondary mineral phases over a wide range of fluid chemistries. However, only brine solutions were capable of precipitating each mineral phase observed in the Angmaat Formation samples, including amorphous silica and silica gel.Hydrous silica phases permeate the sheaths of the organisms, which preserves the individual microorganisms and the complexity of microbial mats. Mat morphologies in the Angmaat Formation preserve a range of taphonomic states, including well-preserved mats that are interpreted to reflect the top layers of mats, to poorly-preserved mats that may reflect buried layers in the mat that were exposed to greater heterotrophic degradation. A taphonomic assessment of the individual microfossils reveals preserved complexity within the microbial mats and a new taphonomic assessment technique is introduced to account for the complexity. Regardless of taphonomic grade, coccoidal microfossils exhibit better preservation than filamentous mat-building organisms. Differential preservation may be related to the motility of the organisms.Organic geochemical characterization of the silicified mats indicates that despite exceptional morphologic preservation, lipids are not preserved in early diagenetic chert. Lipids, specifically hopanes and steranes, could be used to elucidate microbial processes active at the time of silicification and paleoenvironmental conditions. The lack of lipid preservation suggests that silica-rich low-temperature deposits may not be ideal targets for the search of ancient extraterrestrial life
- âŠ