The role of precursory structures on Tertiary deformation in the Black Forest—Hegau region

International Journal of Earth Sciences - Structural inheritance of preexisting crustal discontinuities is widely accepted to have played a crucial role during the Cenozoic tectonic evolution of...     

Improving exposure assessment in environmental epidemiology: Application of spatio-temporal visualization tools

A thorough assessment of human exposure to environmental agents should incorporate mobility patterns and temporal changes in human behaviors and concentrations of contaminants; yet the temporal dimension is often under-emphasized in exposure assessment endeavors, due in part to insufficient tools for visualizing and examining temporal datasets. Spatio-temporal visualization tools are valuable for integrating a temporal component, thus allowing for examination of continuous exposure histories in environmental epidemiologic investigations. An application of these tools to a bladder cancer case-control study in Michigan illustrates continuous exposure life-lines and maps that display smooth, continuous changes over time. Preliminary results suggest increased risk of bladder cancer from combined exposure to arsenic in drinking water (>25 g/day) and heavy smoking (>30 cigarettes/day) in the 1970s and 1980s, and a possible cancer cluster around automotive, paint, and organic chemical industries in the early 1970s. These tools have broad application for examining spatially- and temporally-specific relationships between exposures to environmental risk factors and disease.This study was supported by grant R01 CA96002-10, Geographic-Based Research in Cancer Control and Epidemiology, from the National Cancer Institute. Development of the STIS^TM software was funded by grants R43 ES10220 from the National Institutes of Environmental Health Sciences and R01 CA92669 from the National Cancer Institute. Access to cancer case records was provided by Michigan Cancer Surveillance Program within the Division for Vital Records and Health Statistics, Michigan Department of Community Health. The authors thank Michigan Public Health Institute for conducting the telephone interview and Stacey Fedewa and Lisa Bailey for entering written surveys into a database. The authors thank 3 anonymous reviewers for their helpful comments.     

A method for arc-second determination of solar burst emission centers with high time resolution and sensitivity at 48 GHz

A 48 GHz five-radiometer front end was installed at the Cassegrain focus of the 13.7-m Itapetinga antenna for the observation of solar bursts. The system works with five beam patterns partly overlapping. The five antenna temperatures are recorded with a temporal resolution of 1 millisecond, including time and antenna position. The ratios of the incoming antenna signals are used to determine the centroid of burst emission. Its coordinates are determined from groups of three receivers by using a least-square fit. In favourable observing conditions we obtain an angular accuracy of about 2 arc sec (r.m.s.), with a time resolution of 1 ms and a sensitivity of 0.05 s.f.u. The accuracy of the antenna tracking, the absolute pointing and the quality of radio seeing at Itapetinga are discussed. A preliminary analysis of an impulsive solar burst event is used to illustrate the capabilities of the method described here.     

Compact sources of suprathermal microwave emission detected in quiescent active regions during lunar occultations

Solar quiescent active regions are known to exhibit radio emission from discrete structures. The knowledge of their dimensions and brightness temperatures is essential for understanding the physics of quiescent, confined plasma regions. Solar eclipses of 10 August, 1980 and 26 January, 1990, observed with high sensitivity and high time resolution at 22 GHz, allowed an unprecedented opportunity to identify Fresnel diffraction effects during lunar occultations of active regions. The results indicate the presence of quiescent discrete sources smaller than one arcsecond in one dimension. Assuming symmetrical sources, their brightness temperatures were larger than 2 × 10⁷ K and 8 × 10⁷ K, for the 1980 and 1990 observations, respectively.In memoriam, 1942–1981.     

Search for circular polarized emission from solar hemispheres at microwaves

Solar mappings with moderate angular resolution at 7 GHz seem to support the hemispherical dependence of the sense of circular polarization being right-handed for the southern hemisphere, and left-handed for the northern hemisphere. One explanation of the effect can be found by taking into account the missing fields from active centers, emerging from one hemisphere and immersing into the other.     

On the long-term behaviour of the circular polarization from coronal condensation radio emission at 4.3 cm wavelength

The circular polarization from coronal condensations at = 4.3 cm correspond to the extraordinary mode of propagation, due to the contribution of preceding spots' polarities, being usually left-handed. The fewer cases of right-handed polarization are normally associated to an excess of sunspot plages in the southern hemisphere, thus making it difficult to give evidence for magnetoionic coupling phenomena as a general rule.     

Fast discrete emissions at hard X-rays and sub-mm-IR waves in the impulsive phase of solar bursts

The time profiles of electromagnetic fluxes at hard X-rays and short microwaves are signatures of the energy conversion mechanisms at the origin of solar flares. The distinction between continuum and discrete energy production brings drastic conceptual consequences for the interpretation of the energy conversion processes. As more sensitive detectors were used on measurements with higher time resolution, the notion of continuum energy release in the impulsive phase is being replaced by the concept of repetitive energy production or Elementary Flare Bursts manifested at hard X-rays and by rapid time structures in microwave emissions. These discrete time structures are now known to be as short as tens of milliseconds, and part of their emissions are possibly produced by the same populations of accelerated electrons. Fast spikes, with mm-wave emission fluxes increasing for shorter wavelengths, simultaneous with hard X-rays, bring severe constraints for interpretation. This problem is reviewed, with the suggestion of a possible significant burst emission component in the sub-mm-IR range, due to primeval short-lived explosive compact sources, for which there are still no diagnostics.Dedicated to Cornelis de Jager     

Holocene relative sea-level change, isostatic subsidence and the radial viscosity structure of the mantle of northwest Europe (Belgium, the Netherlands, Germany, southern North Sea)

A comprehensive observational database of Holocene relative sea-level (RSL) index points from northwest Europe (Belgium, the Netherlands, northwest Germany, southern North Sea) has been compiled in order to compare and reassess the data collected from the different countries/regions and by different workers on a common time–depth scale. RSL rise varies in magnitude and form between these regions, revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity. It clearly contains a non-linear, glacio- and/or hydro-isostatic subsidence component, which is only small on the Belgian coastal plain but increases significantly to a value of ca 7.5 m relative to Belgium since 8 cal. ka BP along the northwest German coast. The subsidence is at least in part related to the Post-Glacial collapse of the so-called peripheral forebulge which developed around the Fennoscandian centre of ice loading during the Last Glacial Maximum. The RSL data have been compared to geodynamic Earth models in order to infer the radial viscosity structure of the Earth's mantle underneath NW Europe (lithosphere thickness, upper- and lower-mantle viscosity), and conversely to predict RSL in regions where we have only few observational data (e.g. in the southern North Sea). A very broad range of Earth parameters fit the Belgian RSL data, suggesting that glacial isostatic adjustment (GIA) only had a minor effect on Belgian crustal dynamics during and after the Last Ice Age. In contrast, a narrow range of Earth parameters define the southern North Sea region, reflecting the greater influence of GIA on these deeper/older samples. Modelled RSL data suggest that the zone of maximum forebulge subsidence runs in a relatively narrow, WNW–ESE trending band connecting the German federal state of Lower Saxony with the Dogger Bank area in the southern North Sea. Identification of the effects of local-scale factors such as past changes in tidal range or tectonic activity on the spatial and temporal variations of sea-level index points based on model-data comparisons is possible but is still complicated by the relatively large range of Earth model parameters fitting each RSL curve, emphasising the need for more high-quality observational data.     

Design and implementation of a Space-Time Intelligence System for disease surveillance

Modeling chronic and infectious diseases entails tracking and describing individuals and their attributes (such as disease status, date of diagnosis, risk factors and so on) as they move and change through space and time. Using Geographic Information Systems, researchers can model, visualize and query spatial data, but their ability to address time has been limited by the lack of temporal referencing in the underlying data structures. In this paper, we discuss issues in designing data structures, indexing, and queries for spatio-temporal data within the context of health surveillance. We describe a space-time object model that treats modeled individuals as a chain of linked observations comprised of an ID, space-time coordinate, and time-referenced attributes. Movement models for these modeled individuals are functions that may be simple (e.g. linear, using vector representation) or more complex. We present several spatial, temporal, spatio-temporal and epidemiological queries emergent from the data model. We demonstrate this approach in a representative application, a simulation of the spread of influenza in a hospital ward.This research was supported by grant R44ES010220 from the National Institute of Environmental Health Sciences (NIEHS) and by grants R01CA092669 and R01CA96002 from the National Cancer Institute (NCI). The content of this paper does not necessarily represent the official views of the NIEHS or the NCI.