University of Copenhagen

About: University of Copenhagen is a education organization based out in Copenhagen, Denmark. It is known for research contribution in the topics: Population & Galaxy. The organization has 57645 authors who have published 149740 publications receiving 5903093 citations. The organization is also known as: Copenhagen University & Københavns Universitet.

Environmental and engineering geophysics

Abstract: Geophysical imaging methods provide solutions to a wide range of environmental and engineering problems: protection of soil and groundwater from contamination, disposal of chemical and nuclear waste, geotechnical site testing, landslide and ground subsidence hazard detection, location of archaeological artefacts This book comprehensively describes the theory, data acquisition and interpretation of all of the principal techniques of geophysical surveying: gravity, magnetic, seismic, self-potential, resistivity, induced polarization, electromagnetic, ground-probing radar, radioactivity, geothermal, and geophysical borehole logging A final chapter is devoted to inversion theory and tomography Each chapter is supported by a large number of richly illustrated case histories This book will prove to be a valuable course-book for advanced undergraduates and postgraduates in environmental and applied geophysics, a supplementary course-book for students of geology, engineering geophysics, civil and mining engineering, and a reference work for professional earth scientists, engineers and town planners

Monte carlo methods in geophysical inverse problems

Abstract: [1] Monte Carlo inversion techniques were first used by Earth scientists more than 30 years ago. Since that time they have been applied to a wide range of problems, from the inversion of free oscillation data for whole Earth seismic structure to studies at the meter-scale lengths encountered in exploration seismology. This paper traces the development and application of Monte Carlo methods for inverse problems in the Earth sciences and in particular geophysics. The major developments in theory and application are traced from the earliest work of the Russian school and the pioneering studies in the west by Press [1968] to modern importance sampling and ensemble inference methods. The paper is divided into two parts. The first is a literature review, and the second is a summary of Monte Carlo techniques that are currently popular in geophysics. These include simulated annealing, genetic algorithms, and other importance sampling approaches. The objective is to act as both an introduction for newcomers to the field and a comprehensive reference source for researchers already familiar with Monte Carlo inversion. It is our hope that the paper will serve as a timely summary of an expanding and versatile methodology and also encourage applications to new areas of the Earth sciences.

A Family of Insulin-Like Growth Factor II mRNA-Binding Proteins Represses Translation in Late Development

Abstract: Insulin-like growth factor II (IGF-II) is a major fetal growth factor. The IGF-II gene generates multiple mRNAs with different 5' untranslated regions (5' UTRs) that are translated in a differential manner during development. We have identified a human family of three IGF-II mRNA-binding proteins (IMPs) that exhibit multiple attachments to the 5' UTR from the translationally regulated IGF-II leader 3 mRNA but are unable to bind to the 5' UTR from the constitutively translated IGF-II leader 4 mRNA. IMPs contain the unique combination of two RNA recognition motifs and four hnRNP K homology domains and are homologous to the Xenopus Vera and chicken zipcode-binding proteins. IMP localizes to subcytoplasmic domains in a growth-dependent and cell-specific manner and causes a dose-dependent translational repression of IGF-II leader 3 -luciferase mRNA. Mouse IMPs are produced in a burst at embryonic day 12.5 followed by a decline towards birth, and, similar to IGF-II, IMPs are especially expressed in developing epithelia, muscle, and placenta in both mouse and human embryos. The results imply that cytoplasmic 5' UTR-binding proteins control IGF-II biosynthesis during late mammalian development.

Overview of the Spirit Mars Exploration Rover Mission to Gusev Crater: Landing site to Backstay Rock in the Columbia Hills

Abstract: Spirit landed on the floor of Gusev Crater and conducted initial operations on soil covered, rock-strewn cratered plains underlain by olivine-bearing basalts. Plains surface rocks are covered by wind-blown dust and show evidence for surface enrichment of soluble species as vein and void-filling materials and coatings. The surface enrichment is the result of a minor amount of transport and deposition by aqueous processes. Layered granular deposits were discovered in the Columbia Hills, with outcrops that tend to dip conformably with the topography. The granular rocks are interpreted to be volcanic ash and/or impact ejecta deposits that have been modified by aqueous fluids during and/or after emplacement. Soils consist of basaltic deposits that are weakly cohesive, relatively poorly sorted, and covered by a veneer of wind blown dust. The soils have been homogenized by wind transport over at least the several kilometer length scale traversed by the rover. Mobilization of soluble species has occurred within at least two soil deposits examined. The presence of mono-layers of coarse sand on wind-blown bedforms, together with even spacing of granule-sized surface clasts, suggest that some of the soil surfaces encountered by Spirit have not been modified by wind for some time. On the other hand, dust deposits on the surface and rover deck have changed during the course of the mission. Detection of dust devils, monitoring of the dust opacity and lower boundary layer, and coordinated experiments with orbiters provided new insights into atmosphere-surface dynamics.