Time comparison via OTS-2

The time comparisons carried out via OTS-2 between the Technical University Graz (Austria) and the Van Swinden Laboratory Delft (Netherlands) are discussed. The method is based on the use of the synchronization pulse in the TV-frame of the daily evening broadcasting of a French TV-program to Northern Africa. Corrections, as a consequence of changes in the position of the satellite coordinates are applied weekly after reception of satellite coordinates. A description of the method is given as well as some of the particular techniques used in both the participating laboratories. Preliminary results are presented

Effects of Quaternary Climate Change on Tributary Sedimentation and Geomorphology in Eastern Grand Canyon

Climate variability has had a dramatic impact on eastern Grand Canyon tributaries over the past -100 ky. This is readily observed in the Lava Chuar and Comanche catchments, which host well preserved colluvial remnants and river terraces that resulted from several climate-induced cycles of aggradation and incision. This study investigates these climate responses using surveying, sedimentology, and luminescence geochronology methods to investigate the mechanisms and timing of their deposition. The survey data demonstrate that the concavity of terrace treads is lower than modern drainages. The sedimentology suggests the prevalence of stream-flow reworking of debris flow deposits and portrays an expected down-stream fining of deposits. Results of geochronology indicate that Lava Chuar Creek aggraded from -100-90 ka (S4), 61-55 ka (S3o), 50-35 ka (S3y), and 14-7 ka (S2). Comanche Creek similarly aggraded twice during the time period from 77-35 ka (S3) and also from 26-22 ka (S2). The response of eastern Grand Canyon tributaries to glacial-interglacial climate cycling appears to be more complicated than formerly thought. Previous conceptual models assumed that stream aggradation in arid settings occurred as a response to one specific set of climatic and biologic conditions, but new field data and luminescence dates on terrace materials reveal that there are at least two sets of conditions that were conducive to aggradation along local streams. First, streams aggraded during cooler, wetter climates, which is inferred to be due to increased sediment supply (e.g. S4 and S3y in Lava Chuar). With the transition to warmer interglacial climates came higher intensity storms and decreased vegetation density in catchments, based on previous paleoclimate studies. These conditions caused remobilization and redeposition of older sediment and resulted in a second set of stream aggradation phases (e.g. S3o and S2 in Lava Chuar). Meanwhile, the Colorado River aggraded only once per climate cycle during glacial advances and subsequent climate transitions. Thus, tributaries have responded more frequently and more sensitively to changing local conditions compared to the relatively insensitive Colorado River. This is supported by tighter correlation of tributary records to trends in regional paleoclimate records than to global ice records

Polar UVI images to study steady magnetospheric convection events: Initial results

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94804/1/grl20687.pd

A controlled migration genetic algorithm operator for hardware-in-the-loop experimentation

In this paper, we describe the development of an extended migration operator, which combats the negative effects of noise on the effective search capabilities of genetic algorithms. The research is motivated by the need to minimize the num- ber of evaluations during hardware-in-the-loop experimentation, which can carry a significant cost penalty in terms of time or financial expense. The authors build on previous research, where convergence for search methods such as Simulated Annealing and Variable Neighbourhood search was accelerated by the implementation of an adaptive decision support operator. This methodology was found to be effective in searching noisy data surfaces. Providing that noise is not too significant, Genetic Al- gorithms can prove even more effective guiding experimentation. It will be shown that with the introduction of a Controlled Migration operator into the GA heuristic, data, which repre- sents a significant signal-to-noise ratio, can be searched with significant beneficial effects on the efficiency of hardware-in-the- loop experimentation, without a priori parameter tuning. The method is tested on an engine-in-the-loop experimental example, and shown to bring significant performance benefits

Analysis of seismically-isolated two-block systems using a multi–rocking-body dynamic model

A novel multibody rocking model is developed to investigate the dynamic response of two stacked rigid blocks placed on a linear base isolation device. The model is used to investigate the dynamic response of a realistic statue-pedestal system subject to pulse-like ground motions. The analysis shows that, in general, base isolation increases the safety level of the rocking system. However, for large period pulses or small size blocks, the isolator can amplify the ground motion, resulting in a lower minimum overturning acceleration than for the nonisolated system. Further, the amplification or shock spectrum of a linear mass-dashpot-spring oscillator, was found to be the reciprocal of the minimum nondimensional overturning acceleration of the investigated rocking system. Novel rocking spectra are obtained by normalizing the frequency of the pulse by the frequency of the isolator. The analysis also demonstrates how the dynamic response of the two stacked blocks is equivalent to that of a single-block configuration coincident with the whole system assumed monolithic or the upper block alone, whichever is more slender

Teaching Ethics in Child and Adolescent Psychiatry: Vignette-Based Curriculum

Introduction: Ethics is an integral component of child and adolescent psychiatry. While ethics can seem abstract or philosophical, its tenets are fundamental to the practice of medicine. Understanding relevant ethical principles shapes how practitioners make decisions in all activities, including clinical, administrative, research, and scholarly. Methods: Using the American Academy of Child and Adolescent Psychiatry (AACAP) Code of Ethics as the framework, these vignettes serve as stimulus material to help teach the ethical principles relevant to child and adolescent psychiatry practice. Each vignette briefly describes a clinical situation in practice, followed by questions and possible appropriate responses. The teacher\u27s guide includes a discussion of the relevant ethical principles and perspectives on how to think about the issues involved. A supplementary overview of ethical issues in child and adolescent psychiatry and a list of resources are also provided. Results: We and other child and adolescent psychiatrists have used this curriculum at professional organizational meetings, in residency programs, and in teaching medical students with positive learner responses. Discussion: This curriculum was developed by members of the AACAP Ethics Committee with input from the entire committee in an effort to produce material that was easy to use and provided valuable content about an essential aspect of practice that is relevant to all practitioners at all levels. While designed for child and adolescent psychiatrists, the content is relevant to all physicians working with children, adolescents, and families

Using The Past As The Key To The Present: Informing Coastal Resource Management With Geologic Records

Rising sea levels present an ongoing threat to communities and resources around the Chesapeake Bay, east coast, USA, where tide gauges indicate that the relative rise of sea level is approximately twice the rate of average, eustatic sea-level rise. This has significantly compromised the health and viability of salt marsh habitat on the Eastern Shore during the 20th century, and the biologists who are charged with managing coastal resources in the coming decades need to understand the nature and causes of high rates of regional sea-level rise to develop suitable adaptation plans. Dated geologic deposits and geophysical models suggest that sea-level rise is relatively high on mid-Atlantic coastlines because the land surface is subsiding due to a collapsing glacial forebulge following the Last Glacial Maximum (LGM). To fully understand this process, past sea-level indicators such as dated shoreline deposits are needed to reconstruct regional sea-level behavior in the past, but rigorous age control on geologic deposits is largely restricted to the Holocene and to marine isotope stage (MIS) 5, so the rates and timescales over which these processes operate remain unknown. This research provides long-term paleoenvironmental records from ancient environments under east-central Chesapeake Bay to place the current sea-level threats into the context of a long geologic history of sea-level fluctuations. First, the Pleistocene geologic framework of the region is reconstructed through borehole drilling. Sediments from boreholes provided material for interpreting depositional environments, and for establishing age control for deposits, so that the entire stratigraphy was constrained both in space and time. The geologic framework and ages indicate that Chesapeake Bay alternated between a deeply incised fluvial system and a filled estuary repeatedly in response to major climate fluctuations since at least the early Pleistocene, ~2 Ma. The ages and sedimentology indicate that the field area was submerged intermittently in a shallow estuary until nearly the end of marine isotope stage 3. Because global sea-level proxies suggest that sea level was ~40-80 meters lower than present at that time, these ages suggest that the penultimate glacial forebulge must have remained significantly lowered for nearly 100 ky following the retreat of ice. The implication of this time lag is that mid-Atlantic coastlines are still in a relatively early state of forebulge collapse, and subsidence following retreat of ice from the Last Glacial Maximum will likely continue for the foreseeable future. Ongoing subsidence will continue to exacerbate projected eustatic sea-level rise due to changing global climate, and coastal adaptation plans must remain focused on encouraging the migration of vital habitat toward higher elevations in the landscape

Multi-Temporal InSAR Structural Damage Assessment: The London Crossrail Case Study

Spaceborne multi-temporal interferometric synthetic aperture radar (MT-InSAR) is a monitoring technique capable of extracting line of sight (LOS) cumulative surface displacement measurements with millimeter accuracy. Several improvements in the techniques and datasets quality lead to more effective, near real time assessment and response, and a greater ability of constraining dynamically changing physical processes. Using examples of the COSMO-SkyMed (CSK) system, we present a methodology that bridges the gaps between MT-InSAR and the relative stiffness method for tunnel-induced subsidence damage assessment. The results allow quantification of the effect of the building on the settlement profile. As expected the greenfield deformation assessment tends to provide a conservative estimate in the majority of cases (~ 71% of the analyzed buildings), overestimating tensile strains up to 50%. With this work we show how these two techniques in the field of remote sensing and structural engineering can be synergistically used to complement and replace the traditional ground based analysis by providing an extended coverage and a temporally dense set of data