Stimulated Compton effect and quasi-stellar objects

A computation is presented that predicts with sufficient accuracy the energy transfer between relativistic electrons and radio photons by means of stimulated Compton events. It is shown that the majority of currently assumed parameters for quasi-stellar objects result in situations where the relativistic electrons must be producedinitially at rather high energies (10²–10³) in order to survive for any appreciable length of time.     

Predicting the impact of land use on the major element and nutrient fluxes in coastal Mediterranean rivers: The case of the Têt River (Southern France)

This study presents a detailed discrimination between the natural and anthropogenic sources of dissolved major elements in the Têt River, a typical small coastal river in the south of France. The main objectives were to quantify the materials that were released by human activities in the basin, and to determine the specific element inputs for the major land use forms. The dissolved material fluxes were estimated by weekly monitoring over a hydrological year (2000–2001) along the major water gauging stations, and the flux relationships were examined in the context of anthropogenic and natural basin characteristics as determined by a Geographical Information System (GIS). Intensive agricultural land use in the form of fruit tree cultures and vineyards has a strong control on the dissolved element fluxes in the river. Area specific element releases for these cultures are greatest for SO₄, with an estimated average of about 430 ± 18 keq km⁻² a⁻¹. This is ?11 times the natural SO₄ release by rock weathering. Also for K, NO₃, PO₄ and Mg, the specific releases were ?6 times the natural weathering rates (respectively about 44, 60, 4 and 265 keq km⁻² a⁻¹). Waste-waters are the other major source of anthropogenic elements in the river. They have an important role for the fluxes of inorganic P and N, but they are also a considerable source of Cl and Na to the river. For example, the average annual release of Cl is around 150 moles/inhabitant in the rural basin parts. Further downstream, however, where population density strongly increases, industrial effluents can enhance this value (>300 moles/inhabitant). The waste-waters contribute more than 70% of the dissolved inorganic N export to the sea, although their contribution to the average DOC export is almost negligible (3%).     

Li abundances in eclogite minerals: a clue to a crustal or mantle origin?

The mineral phases of 33 eclogite and garnet clinopyroxenite samples from various tectonic settings were analysed for Li by secondary ion mass spectrometry (SIMS). In all samples, Li is preferentially incorporated into clinopyroxene (0.4 to 80 µg/g), whereas co-existing garnet contains only minor amounts of Li (0.01 to 3.7 µg/g). When present, glaucophane shows Li abundances which are similar to those of clinopyroxene, but phengite contains significantly less Li than clinopyroxene. Additional phases, such as amphibole, quartz, clinozoisite and kyanite, have low Li concentrations (<1 µg/g). No correlation is apparent between the Li contents and major-element compositions of clinopyroxene or garnet. On the basis of both measured Li concentrations in clinopyroxene and estimated Li abundances in the whole rocks, the investigated samples can be subdivided into high-Li and low-Li groups. These groups coincide with the mode of origin of the rocks. Metabasaltic (metagabbroic) eclogites from high-pressure terranes belong to the high-Li group whereas, except for one eclogite, all kimberlite- and basanite-hosted xenoliths have low Li contents. Samples from eclogites and garnet clinopyroxenites associated with orogenic peridotites fall into both groups. It is suggested that the high-Li eclogites originated from basaltic oceanic crust whereby the notable Li enrichment of some samples was probably caused by low-temperature hydrothermal alteration prior to subduction. Furthermore, the low-Li eclogites and garnet clinopyroxenites may represent high-pressure cumulates from mafic melts percolating through the mantle.     

Creep stress analysis of frozen soils under multiaxial states of stress

Creep behaviour of the so called Emscher-Marl is investigated in uniaxial compression tests under a temperature of −10°C. Similar to the results of creep tests published elsewhere, it is shown that the secondary creep controls the deformation. In cases of stationary creep the material behaves like a nonlinear elasto-viscous Maxwell fluid. Assuming no hydrostatic pressure effect, the power law applied to the uniaxial case can be transformed to multiaxial states of stress. For structures of frozen soil with a long-term deformation process Norton's power relationship between stress and rate of steady flow leads to reasonable results. As a numerical solution a finite-element computer program in connection with incremental procedure is developed for treatment of creep problems in groundfreezing technology. The calculation of a simply supported beam demonstrates the important influence of the high nonlinearity in stress and strain for frozen soils.     

Elektroklimatologie

Zusammenfassung Von den physiologisch interessanten Umwelteinflüssen (Tabelle 1) werden die Atmospherics betrachtet. Die bekannten örtlichen Schwankungen der Atmospherics nach Feldstärke, Träger- und Folgefrequenz werden anhand eines Modells (Abb. 2, 3) mit Mikrowellen nachgebildet, (Abb. 4) und Messungen an natürlichen Atmospherics im Freien und in abschirmenden Gebäuden gegenübergestellt (Abb. 5 und Tabellen 3, 4). Der örtliche mittlere Atmosphericspegel ist entscheidend vom Grundwassergehalt abhängig; die mittlere Folgefrequenz aller Impulse obserhalb einer elektrischen Feldstärke von 100 mV/m liegt bei einer Bandbreite von 100 kHz zwischen 0,05 Hz (Schonklima) und 1,40 Hz (Reizklima).Für die Schwankungen der Folgefrequenz wird eine statistische FunktionS eingeführt. Die Atmospherics-Transparenzen von Gebäuden liegen zwischen 95% (Stein) und 3% (Stahl-Aluminium-Haus).

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Summary The atmospherics among the physiological interesting parameters are examined. Well known local variations of electrical field strength, carrierfrequency and series-frequency are discussed by means of a microwave-model (Figs. 2, 3, 4).The results of measurments of natural atmospherics outside and inside houses are collected in Fig. 5 and Tables 3, 4. Local distribution of atmospherics is a function of underground waterlevel. Mean series-frequency of impulses greater than 100 mV/m, measured with 100 kcps bandwidth lies between 0.05 cps (tender climate) and 1.40 cps (stimulating climate). A statistical functionS is introduced to describe variations of the series-frequency. The transparency of brickhouses reaches 95%, while houses made of steel-aluminium combination-walls have transparencies down to 3%.

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Résumé On considère ici les atmosphériques parmi les influences du milieu les plus intéressantes du point de vue physiologique (Tableau 1). On reproduit au moyen d'un modèle d'ondes micrométriques (Fig. 4) les variations locales connues des atmosphériques selon l'intensité du champ, la fréquence des ondes porteuses et celle de succession. On les compare ensuite à des mesures d'atmosphériques naturels effectuées à l'air libre et dans des locaux sous écrans (Fig. 5 et Tableaux 3 et 4). Le niveau local moyen des atmosphériques dépend étroitement de la nappe phréatique. La fréquence moyenne de succession de tous les impulsions supérieurs à une intensité du champs de 100 mV/m se trouve, dans une bande de 100 kHz, située entre 0,05 Hz (climat sédatif) et 1,40 Hz (climat stimulant). On introduit ensuite une fonction statistiqueS pour les fluctuations de la fréquence de succession. La perméabilité des bâtiments aux atmosphériques se situe entre 95% pour la pierre et 3% pour les maisons d'acier et d'aluminium.

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Mit 5 Abbildungen     

Origins and genesis of loess deposits in central Spain,as indicated by heavy mineral compositions and grain‐size variability

The formation of loess deposits strongly depends on the availability of deflatable dust‐sized material. Identification of source areas and mechanisms of dust production is essential for an appropriate characterization of related palaeoenvironmental conditions. So far, little research has been done on loess deposits in the Mediterranean region and information about mechanisms of dust production is very rare. In this context, it is not clear from where the loess deposits from the upper Tagus Basin in central Spain originated. The main objective of this study was to find out whether these loess deposits were formed primarily by mountain processes and fluvial comminution, or whether they have their origin in the weathering of Tertiary marls in the centre of the Madrid Basin. A further concern was to link the determined source areas with loess formation mechanisms and concomitant environmental contexts. Following a comprehensive approach using heavy minerals and grain‐size data, together with information on stratigraphic features and geomorphic positions, different local loess sources could be identified. This study shows that during the last 35 kyr a major proportion of the Tagus loess deposits was deflated from river floodplains, while the mountain region of the Iberian Range was identified as a significant source of respective floodplain sediments. Based on heavy mineral compositions and dating results, it was found that during Heinrich Stadial 3, sediment supply from the Iberian Range strongly increased, suggesting an environmental shift from initially warmer towards colder temperatures in late Marine Isotope Stage 3. Furthermore, it was found that grain‐size patterns clearly indicate maximum wind strengths during Heinrich Stadial 3, followed by Heinrich Stadial 2 and Heinrich Stadial 1. These results demonstrate that the formation of dust‐sized particles in this part of the Mediterranean operated similar to many other places in temperate and continental regions, and that weathering processes linked to hot and dry environments were only of minor importance.     

Influence of glacier advance on the development of the multipart Riffeltal rock glacier,Central Austrian Alps

The multipart Riffeltal rock glacier, located in a tributary valley of the Kaunertal, Tyrol, Austria is investigated to enlarge the knowledge about spatial and temporal development of rock glaciers in and at the margins of pro‐glacial areas and to get a better understanding of glacier–rock glacier interactions. The subject of interest consists of a complex system of two adjacent rock glacier tongues and various superposed lobes with differing ages, origin and root zones, and therefore diverse development. To determine the reasons for their diverging development, the internal structure and permafrost occurrence on and in the surrounding area of the rock glacier were studied by application of geomorphological mapping, geophysical methods and measurement of the basal temperature of the winter snow cover (BTS). Permafrost modelling was performed on the basis of BTS data and land surface parameters derived from a high resolution airborne laser scanning (ALS) digital elevation model (DEM). Additionally, the ALS data were used to measure vertical and horizontal changes of the rock glacier surface between 2006 and 2012. Glacier–rock glacier interactions during and since the Little Ice Age (LIA) are evident for the development of the studied rock glacier. A geomorphic map gives important information about the connection between glacial advance or retreat and permafrost or ground ice occurrence. The combination of all information helps in the analysis of diverse kinematic action of neighbouring rock glacier tongues. Copyright © 2014 John Wiley & Sons, Ltd.     

Aurora borealis lag during the Maunder minimum

Observations of 121 occurrences of the aurora borealis recorded in Central Europe from 1645 to 1712 C.E. are compared with known phase relationships between auroral activity and sunspot cycles in modern times. A remarkable analogy of the aurora borealis cycles during the Maunder minimum is found, both with respect to phase-dependent frequency and to delayed maxima, with aurorae during the 19th and 20th centuries.