Review of Geotechnical Investigations Resulting from the Roermond April 13, 1992 Earthquake

In 1987 the Engineering Geology section of the Delft University of Technology carried out a survey of the SE Netherlands to determine which areas were susceptible to liquefaction based on soil profile, groundwater levels and a Richter scale magnitude 6 earthquake along the principal rift fault through the Netherlands, the Peelrand fault system. The fault system has been active since the Triassic and forms part of the Rhine-North Sea rift system. The last major earthquake along the Peelrand fault was in 1933. Recently, in 1992, A 5.8 magnitude earthquake occurred at Roermond, near to the Dutch-German border. Though damage resulting from the earthquake was limited, remedial works to structures amounted to US$ 50 million in the Netherlands. The paper reviews geotechnical investigations associated with the earthquake carried out in the Netherlands. Much of the damage is attributed to liquefaction; excess pore pressures resulting from the earthquake caused sand vent eruptions, river-dyke failures and slope failures. Comparisons are made between the predictions of 1987 and that which occurred in 1992. Site investigation works are recording geotechnical and building data so as to allow for correlations between extents of damage, ground geotechnical profiles and building design. Models for liquefaction are reviewed to describe the slope failure as well as the sand vent phenomena. Densification of subsoil has been inferred from CPTs taken before and after the earthquake for some sites. Pile foundation damage has been investigated for buildings in Roermond for which their susceptibility to earthquake lateral forces in terms of stiffness and pile head working load is given

Polymer reptation and nucleosome repositioning

We consider how beads can diffuse along a chain that wraps them, without becoming displaced from the chain; our proposed mechanism is analogous to the reptation of "stored length" in more familiar situations of polymer dynamics. The problem arises in the case of globular aggregates of proteins (histones) that are wound by DNA in the chromosomes of plants and animals; these beads (nucleosomes) are multiply wrapped and yet are able to reposition themselves over long distances, while remaining bound by the DNA chain.Comment: 9 pages, including 2 figures, to be published in Phys. Rev. Let

Sequence Effects on DNA Entropic Elasticity

DNA stretching experiments are usually interpreted using the worm-like chain model; the persistence length A appearing in the model is then interpreted as the elastic stiffness of the double helix. In fact the persistence length obtained by this method is a combination of bend stiffness and intrinsic bend effects reflecting sequence information, just as at zero stretching force. This observation resolves the discrepancy between the value of A measured in these experiments and the larger ``dynamic persistence length'' measured by other means. On the other hand, the twist persistence length deduced from torsionally-constrained stretching experiments suffers no such correction. Our calculation is very simple and analytic; it applies to DNA and other polymers with weak intrinsic disorder.Comment: LaTeX; postscript available at http://dept.physics.upenn.edu/~nelson/index.shtm

Constraints, Histones, and the 30 Nanometer Spiral

We investigate the mechanical stability of a segment of DNA wrapped around a histone in the nucleosome configuration. The assumption underlying this investigation is that the proper model for this packaging arrangement is that of an elastic rod that is free to twist and that writhes subject to mechanical constraints. We find that the number of constraints required to stabilize the nuclesome configuration is determined by the length of the segment, the number of times the DNA wraps around the histone spool, and the specific constraints utilized. While it can be shown that four constraints suffice, in principle, to insure stability of the nucleosome, a proper choice must be made to guarantee the effectiveness of this minimal number. The optimal choice of constraints appears to bear a relation to the existence of a spiral ridge on the surface of the histone octamer. The particular configuration that we investigate is related to the 30 nanometer spiral, a higher-order organization of DNA in chromatin.Comment: ReVTeX, 15 pages, 18 figure

Activity of different desoximetasone preparations compared to other topical corticosteroids in the vasoconstriction assay

Introduction: We report on a double-blind, vehicle-controlled, single-center confirmatory study with random assignment. The purpose of the study was to investigate the topical bioavailability of different topical corticosteroid formulations in healthy human beings focussing on desoximetasone (DM). Materials and Methods: Two DM 0.25% formulations {[}ointment (DM-o) and fatty ointment (DM-fo, water-free); class III corticosteroids], the corresponding active ingredient-free vehicles and three comparators of different strength {[}clobetasol propionate 0.05% (CP 0.05%), fatty ointment, class IV; hydrocortisone (HC) 1%, fatty ointment, class I, and betamethasone (BM) 0.05%, fatty ointment, class III] were tested using the vasoconstriction assay. The degree of vasoconstriction (blanching) in the treatment field was compared to the one found in untreated control fields using chromametric measurements and clinical assessment. Results/Conclusion: DM-o 0.25%, DM-fo 0.25% and BM 0.05% showed similar vasoconstrictive potential, i.e., clear blanching. In fact, both DM preparations were proven to be non-inferior to BM 0.05%, while CP 0.05% was found a little less active. HC 1.0% and the DM vehicles showed no clear-cut vasoconstrictive effect. No adverse events related to the study medications were observed. Good topical bioavailability of both DM formulations was detected by chromametric measurement and clinical assessment. Copyright (C) 2008 S. Karger AG, Basel

VPLanet: The Virtual Planet Simulator

We describe a software package called VPLanet that simulates fundamental aspects of planetary system evolution over Gyr timescales, with a focus on investigating habitable worlds. In this initial release, eleven physics modules are included that model internal, atmospheric, rotational, orbital, stellar, and galactic processes. Many of these modules can be coupled simultaneously to simulate the evolution of terrestrial planets, gaseous planets, and stars. The code is validated by reproducing a selection of observations and past results. VPLanet is written in C and designed so that the user can choose the physics modules to apply to an individual object at runtime without recompiling, i.e., a single executable can simulate the diverse phenomena that are relevant to a wide range of planetary and stellar systems. This feature is enabled by matrices and vectors of function pointers that are dynamically allocated and populated based on user input. The speed and modularity of VPLanet enables large parameter sweeps and the versatility to add/remove physical phenomena to assess their importance. VPLanet is publicly available from a repository that contains extensive documentation, numerous examples, Python scripts for plotting and data management, and infrastructure for community input and future development.Comment: 75 pages, 34 figures, 10 tables, accepted to the Proceedings of the Astronomical Society of the Pacific. Source code, documentation, and examples available at https://github.com/VirtualPlanetaryLaboratory/vplane

Health Information Seeking on Behalf of Others: Characteristics of ‘Surrogate Seekers’

Understanding the health information seeking behaviors of surrogate seekers (those who seek health information for others) may guide efforts to reach disadvantaged populations. We used 2011-2012 data from the Health Information National Trends Survey to describe the behaviors of online surrogate seekers. Respondents were asked about their use of the Internet for surrogate seeking over the prior 12 months. Data were weighted to calculate population estimates. Compared to those who sought health information online for only themselves, surrogate seekers were more likely to live in households with others (weighted percent 89.4% vs. 82.5% of self-seekers; p \u3c 0.05); no significant differences in gender, race, income or education were observed. Surrogate seekers were more likely to report: visits to social networking sites to read and share about medical topics; participation in online health support groups and downloading of health information to electronic devices. On multivariate analysis, those who had looked online for a healthcare provider were more likely to be surrogate seekers (OR 1.67, 95% CI 1.08-2.59). Our results offer insight for leveraging health communication efforts to reach populations who rely upon surrogate seekers for health information