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Holocene peat bog deposits in Northem Germany have been studied by physical, chemical, and petrological methods for the presence of (microscopic) tephra layers. Aim of this study was the detection, chemical-petrological characterization and conelation of isochronous tephra layers in the peat sequences, and the identification of their volcanic sources, and contribution to a tephrostratigraphic dating framework of Northem Europe through the definition and coITelation of regionally widespread tephrostratigraphic marker horizons. The raised peat bogs studied (Jardelunder Moor, Dosenmoor/Neumünster, Grambower Moor) are located along a northwest-southeast transsect, extending from Denmark via Schleswig-Holstein to Mecklenburg-Vorpommern. Their Holocene peat deposits comprise a time span ranging from Preboreal to present. A total of four cores was analyzed, three of which represent the central ranges of the peat bogs. In order to verify the local reproducibility/persistance of tephra layers, an additional core was studied from the marginal facies of the Dosenmoor, the bog showing the highest peat accumulation rate among the sections studied. None of the cores contained visible ash layers. Moreover, volcanic ash horizons could not be detected by non-destructive physical detection methods, including measurements of magnetic suszeptibility, saturation isothermal remanent magnetization (SIRM), and detection of natural gamma and alpha ray emmissions. By contiguous sampling in 4-6 cm intervals of the up to 750 cm long cores and enrichment of inorganic components by buming and chemical digestion techniques, 37 tephra horizons were found within the mineral residue at different levels of the cores. Glass shards occur in well-defined horizons with concentrations ranging from 30 shards/cm3 sample. Single glass shards are up to 115 μm in diameter, the median of the glass shards being generelly 65 wt%), and rarely andesitic (Si02 1000 years) were also identified in Northern German sections (Hekla 5: JART-2/LairgA; JART-1/LairgB/Hoy; Hekla 4: DOST-9; DOST-5/Glen Garry; DOST-2/Sluggan B; oblique = local British tephra names). Two of the most prominent tephra layers found in Northern German peat sections, however, Hekla-3 ash and DOST-6 ("Microlite-tephra"), have only been identified in Northern Germany as yet. Glass particles occuring in the younger sections ( 2000 km) facies, at least during the last 7 000 years. Transport directions and dispersal pattem of Holocene Icelandic tephra fall out fans petfectly agree with present-day wind directions and velocities in the Northern hemispheric tropopause. Nanow, highly elongated fallout fans (Hekla-3) reflect the control of high jetstream wind velocities on the ash dispersal. A relatively low tropopause height above Iceland (8-11 km), and frequent establishment of a polar front jetstream over Northern Europe during much of the Holocene, are considered to represent the cause of the unusually wide ash dispersal. Entry into the tropopause and transport by high-speed polar front jetstreams resulted in aerial and grain-size distributions even of minor (VEI≤3) Icelandic eruptions, which are otherwise characteristic of major explosive events with orders of magnitude larger tephra and magma eruption volumes.

To investigate the value of the plain abdominal radiograph in the assessment of constipation we prospectively studied 30 patients (20 females, 10 males, mean age 48.6 years, range 21-76 years). These patients underwent the following tests: plain abdominal radiograph in supine position, measurement of stool weight (mean of 5 days) and whole gut transit time (20 radioopaque pellets, fluoroscopy of stools). All patients completed a questionnaire regarding their defaecation characteristics (a.o. average defaecation frequency and faecal consistency). The abdominal films were coded and independently scored for the degree of faecal stasis in ascending, transverse, descending colon and rectosigmoid by four gastroenterologists. To each of these parts of the colon a score of 1 (no faeces) to 4 (loaded with faeces) was assigned. The film scores given by the four observers were significantly correlated (p less than 0.001). Significant correlations were found between the radiograph scores and frequency of defaecation, faecal consistency and stool weight. The strength of these correlations were of the same order of magnitude as those between the other subjective and objective defaecation variables. The scores for the left colon (descending colon and rectosigmoid) showed a better correlation with the other defaecation parameters than the scores for the right colon. It is concluded that in the assessment of constipation a simple plain abdominal radiograph is as reliable as measurement of faecal weight or marker transit and can thus be advocated as the first procedure. When an abdominal radiograph is used for this purpose the stasis in the descending and sigmoid colon provides most information

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