The re-analysis of the ROSAT data of Nova Mus 1983 using white dwarf atmosphere emission models

The analyses of X-ray emission from classical novae during the outburst stage have shown that the soft X-ray emission below 1 keV, which is thought to originate from the photosphere of the white dwarf, is inconsistent with the simple blackbody model of emission. Thus, ROSAT Position Sensitive Proportional Counter (PSPC) archival data of the classical Nova Mus 1983 (GQ Mus) have been re-analysed in order to understand the spectral development in the X-ray wavelengths during the outburst stage. The X-ray spectra are fitted with the hot white dwarf (WD) atmosphere emission models developed for the remnants of classical novae near the Eddington luminosity. The post-outburst X-ray spectra of the remnant white dwarf are examined in the context of evolution on the Hertzsprung–Russell diagram using C–O enhanced atmosphere models. The data obtained in 1991 August (during the ROSAT All Sky Survey) indicate that the effective temperature is         . The 1992 February data show that the white dwarf had reached an effective temperature in the range         with an unabsorbed X-ray flux (i.e. ∼ bolometric flux) between     and     . We show that the H burning at the surface of the WD had most likely ceased at the time of the X-ray observations. Only the 1991 August data show evidence for ongoing H burning.     

Readout Techniques for Drift and Low Frequency Noise Rejection in Infrared Arrays

Three different methods are presented to subtract thermal drifts and low-frequency noise from the signal of infrared array. The first is dead pixels with open Indium bumps, the second is reference output as implemented on the Hawaii2 multiplexer, and the third is dark pixels to emulate reference cells having a capacity connected to the gate of the unit cell field-effect transistor (FET). The third method is the most effective and yields a reduction in readout noise from15.4–9.4 erms. A novel method will be described to extend this readout technique to the Aladdin 1 K × 1 K InSb array. This revised version was published online in July 2006 with corrections to the Cover Date.     

Modelling the effect of low soil temperatures on transpiration by Scots pine

For ecosystem modelling of the Boreal forest it is important to include processes associated with low soil temperature during spring‐early summer, as these affect the tree water uptake. The COUP model, a physically based SVAT model, was tested with 2 years of soil and snow physical measurements and sap flow measurements in a 70‐year‐old Scots pine stand in the boreal zone of northern Sweden. During the first year the extent and duration of soil frost was manipulated in the field. The model was successful in reproducing the timing of the soil warming after the snowmelt and frost thaw. A delayed soil warming, into the growing season, severely reduced the transpiration. We demonstrated the potential for considerable overestimation of transpiration by the model if the reduction of the trees' capacity to transpire due to low soil temperatures is not taken into account. We also demonstrated that the accumulated effect of aboveground conditions could be included when simulating the relationship between soil temperature and tree water uptake. This improved the estimated transpiration for the control plot and when soil warming was delayed into the growing season. The study illustrates the need of including antecedent conditions on root growth in the model in order to catch these effects on transpiration. The COUP model is a promising tool for predicting transpiration in high‐latitude stands. Copyright © 2006 John Wiley & Sons, Ltd.     

Income distribution dynamics and cross-region convergence in Europe

This paper presents a continuous version of the model of distribution dynamics to analyse the transition dynamics and implied long-run behaviour of the EU-27 NUTS-2 regions over the period 1995–2003. It departs from previous research in two respects: first, by introducing kernel estimation and three-dimensional stacked conditional density plots as well as highest density regions plots for the visualisation of the transition function, based on Hyndman et al. (J Comput Graph Stat 5(4):315–336, 1996), and second, by combining Getis’ spatial filtering view with kernel estimation to explicitly account for the spatial dimension of the growth process. The results of the analysis indicate a very slow catching-up of the poorest regions with the richer ones, a process of shifting away of a small group of very rich regions, and highlight the importance of geography in understanding regional income distribution dynamics.

Geochronology of Middle and Upper Pleistocene Loess Sections in Hungary

The application of both thermoluminescence and infrared stimulated luminescence dating to the extensively studied “classical” Hungarian loess/paleosol sequences from Basaharc, Mende, and Paks provides a reliable chronological framework and climatostratigraphic reconstruction for the last interglacial/glacial cycle. Based on this combined luminescence dating study a new chronology is proposed for the “Young Loess” in Hungary. Luminescence dating suggests that the loess below the MF2 horizon formed during the penultimate glaciation. The MF1 horizon probably formed during an interstade within oxygen isotope stage 3. For the youngest loess, overlying MF1, a very high accumulation rate was determined. Large time gaps occur above MF2 and MF1, indicating that most of the record of the last glaciation is missing in the standard sections at Basaharc, Mende, and Paks. Either large discontinuities or a very low accumulation rate occurred in all three type sections during the soil-forming periods. High-resolution studies of climatic proxies using this combined luminescence dating approach provide a reliable chronological framework for loess and loess derivatives of the last glacial cycle in Hungary, although a precise and complete chronostratigraphic reconstruction cannot be achieved from the incomplete records found at these sites.     

探测冰盖和多年冻土层的融冰探头研发

The exploration of ice sheets by melting vertical holes into the ground has some tradition in terrestrial glaciology. Such probes have been used since the 1960's to investigate the vertical structure of the ice in Greenland and Antarctica and in alpine glaciers. In this paper we look into the possibility to develop similar devices for use on extraterrestrial icy bodies, like e.g. the polar areas on Mars or the icy satellites of the outer solar system. We report on some basic experiments performed in the cryo-vacuum laboratory of the Space Research Institute of the Austrian Academy of Sciences, Graz. In these experiments the penetration of a simple melting probe into compact and porous water ice (with a snow-like texture) was monitored, both under vacuum conditions and under air pressure. The observed penetration speeds for a given power supply are compared with a simple mathematical model. We conclude that a miniature melting probe with small overall dimensions and a reasonable power demand could well be part of the payload of a future planetary mission, for example to the poles of Mars. Such missions are currently under discussion in several space agencies. Moreover such probes could also e? ectively be used in terrestrial environments. A possible design is presented at the end of the paper.     

Mauer – the type site of Homo heidelbergensis: palaeoenvironment and age

The mandible of Homo heidelbergensis was found 1907 in the sand pit Grafenrain at Mauer in coarse fluvial sands 24 m below the surface, deposited in a former course of the Neckar River. These ‘Mauer sands’ are overlain by a series of glacial-climate loess deposits with intercalated interglacial palaeosols, which can be correlated with Quaternary climate history, thus indicating an early Middle Pleistocene age for H. heidelbergensis. The ‘Mauer sands’ are famous for their rather rich mammal fauna, which clearly indicates interglacial climate conditions. The faunal evidence – in particular the micromammals – place the ‘Mauer sands’ into MIS 15 or MIS 13 although most stratigraphic arguments favour correlation to MIS 15 and therefore to an age of ca 600 ka.     

Kenntnis der Randstrukturen des Witwatersrand-Beckens im nördlichen Oranje-Freistaat-Goldfeld (Südafrika)

Zusammenfassung Eine Analyse der Randstrukturen des Witwatersrand-Beckens im nördlichen Oranje-Freistaat-Goldfeld zeigt, daß das tektonische Bild der Beckenrandregion nacheinander durch verschiedene Deformationsakte von unterschiedlichem Charakter geprägt worden ist. Auf eine Einengungsphase von spät-Witwatersrand-Alter, die zur Bildung einer randlichen Aufrichtungszone und zum Aufreißen eines Systems von 'normalen und antivergenten Aufschiebungen führte, folgte während des Unteren Ventersdorp eine jüngere Zerrungsphase, bei der es zu einem staffeiförmlgen Zerbrechen der ursprünglich eingeengten Scholle kam. Die Zerrung hängt sehr wahrscheinlich mit dem Zerbrechen der Beckenrandregion während oder unmittelbar nach der Extrusion der Unteren Ventersdorp-Laven zusammen. Dabei wurde ein schmaler randparalleler Streifen der Beckenfüllung in einem Graben versenkt ('Odendaalsrus-Graben). Die abgesunkenen Schollenteile sind in sich noch stark zerbrochen und gewöhnlich schiefgestellt. Da der versenkte Streifen durch ein primäres Einmuldungsstadium hindurchgegangen ist, deutet die Grabenbildung offenbar eine Fortsetzung der Beckenbildungsvorgänge 'mit anderen Mitteln an. — Die Bewegungen haben ein Alter von etwa 2,1 Mrd. Jahren; sie fallen somit ins frühe Präkambrium und sind keinesfalls 'intraalgonkisch, wie es noch bis in die jüngste Vergangenheit angenommen wurde.Tektonische Experimente haben ergeben, daß sich die wichtigsten Störungssysteme der realen Beckenrandstrukturen bei entsprechend gewählter Versuchsanordnung auch künstlich erzeugen lassen.

---

The Orange Free State goldfield represents the southernmost part of the Witwatersrand Basin (Fig. 1) which is completely buried under a cover of Ventersdorp and Karroo rocks. The pre-Karroo geology of this area is characterized by a major rift system trending SSW-NNE ('Odendaalsrus graben), followed to the east by a V-shaped horst and two minor rift blocks (Fig. 2). The main graben is bounded by two principal faults (Border Fault, De Bron Fault, Fig. 4) which are roughly parallel to the western rim of the basin.A tectonic analysis of the basin-edge structures in the northern part of the graben reveals that the basin rim has been subjected to a sequence of deformational acts working over a considerable period of time. A primary compression of the basin-edge region in Upper Witwatersrand times resulted in the formation of a marginal fold; since sedimentation continued, the different stages of the folding process were sometimes preserved by a set of minor unconformities within the youngest sediments (Elsburg A Reefs, Fig. 5). With increasing lateral pressure a couple of reverse faults developed to support the folding (faults No. 10 and 11, Figs. 6 and 7); the minor thrust faults No. 19 and 21 represent the second component of this fault system. A reconstruction of the original depositional plain of the Lower Agglomerate shows that the main thrust faults (No. 10 and 11) are definitely older than the Elsburg A 1 Reef and have been obviously revived after the younger sediments had been laid down (Fig. 8 a).In a later stage compression gave way to tensional forces bringing about a fracturing of the overturned limb of the marginal fold along normal faults (faults No. 4 and 7, Figs. 6 and 7). There is reason to believe that the tensional phase was associated with the incipient rifting during early Ventersdorp times and that these faults were more or less contemporaneous with the general tilting of the basin-edge as displayed to-day (cf. Figs. 3 and 4). Because of the westerly tilt the Boulder Beds dip towards the west, although they must have been originally deposited on a ± horizontal or slightly basinward dipping plain. Faulting was mostly accomplished before deposition of the Ventersdorp sediments and the Upper Ventersdorp Lavas took place; the latter are seldom or only to a small degree affected by the fractures (Figs. 3 and 4). — The age of the tectonics is about 2,1×10⁹ years, i. e. early Precambrian and not Algonkian as formerly supposed.Experimental work aiming at an imitation of the observed basin-edge structures has shown that the principal tectonic features can be produced artificially (Figs. 8 a and b). This refers in particular to the main system of thrust-faults as well as to the younger step-faults caused by tension.

---

Résumé Les structures tectoniques au bord du Bassin de Witwatersrand dans le district de mines d'or septentrional de la République d'Orange (Afrique du Sud) ont été analysées. Il s'est montré qu'elles sont déterminées par l'action de plusieurs phases de déformation successives de caractères différents. Une phase de compression d'âge Witwatersrand supérieur a d'abord amené un redressement des couches dans une zone marginale du bassin, avec chevauchements à vergences «normales» et inverses. Elle était suivie pendant le Ventersdorp inférieur d'une phase de traction qui produisit des cassures en gradins dans le secteur primitivement comprimé. La traction est très vraisemblablement en relation avec l'effondrement de la zone marginale du bassin pendant ou peu après l'extrusion des laves inférieures de Ventersdorp. Une bande étroite de sédiments, parallèle au bord du bassin, fut alors affectée d'un affaissement (formation du «graben d'Odendaalsrus») où de nombreuses cassures à l'intérieur des compartiments affaissés ont résulté dans la formation de blocs plus ou moins inclinés. Puisque cette zone a d'abord passé par un stade synclinal, on a l'impression que l'effondrement du graben ne représente que la reprise de l'affaissement général du bassin à l'aide d'une «technique nouvelle». - Les mouvements ont un âge de 2.1 milliards d'années, ils datent par conséquent du Précambrien inférieur et ne sont point «intra-algonkiques» comme il fut encore admis tout récemment.Il a été possible de reproduire artificiellement les systèmes de failles les plus importants de la zone marginale du bassin, si les conditions de l'expériment étaient favorables.

---

Witwatersrand . . 2,1 , . . . , .

     

Correlation of the Quaternary terrace sequence in the Lower Rhine valley and northern Alpine foothills of central Europe

Thirteen glacial terraces are known from the western part of the northern Alpine foothills between the Lech and Iller Rivers. In the Lower Rhine region of West Germany, a similar number of terraces are capped by interglacial floodloams and soils. Whereas the environment during individual interglaciations did not differ substantially, the glaciations were progressively more severe. The Main Terrace system of the Rhine may be an exception. The duration of the Quaternary, starting at the base of Praetiglian, is estimated at approximately 2 million yr by paleomagnetic dating. The major cold-warm climatic cycles of the earliest Pleistocene lasted approximately 100,000 yr, the same as those of the Brunhes Chron. The intervening Main Terrace system has not yet been climatically subdivided. Correlation with the Netherlands is possible because of an abundance of paleobotanic and paleomagnetic evidence. In the Alpine foothills, stratigraphically useful indicators of warm climates are missing, but analogies in terrace development permit comparison with the Lower Rhine and Danube. The terrace sequence in the Alpine foothills is incomplete, as are those along most of the other rivers in Europe. Some of the older terraces may have been eroded.     

Numerical modeling for analyzing thermal surface anomalies induced by underground coal fires

Coal seams burning underneath the surface are recognized all over the world and have drawn increasing public attention in the past years. Frequently, such fires are analyzed by detecting anomalies like increased exhaust gas concentrations and soil temperatures at the surface. A proper analysis presumes the understanding of involved processes, which determine the spatial distribution and dynamic behavior of the anomalies.In this paper, we explain the relevance of mechanical and energy transport processes with respect to the occurrence of temperature anomalies at the surface. Two approaches are presented, aiming to obtain insight into the underground coal fire situation: In-situ temperature mapping and numerical simulation. In 2000 to 2005, annual temperature mapping in the Wuda (Inner Mongolia, PR China) coal fire area showed that most thermal anomalies on the surface are closely related to fractures, where hot exhaust gases from the coal fire are released. Those fractures develop due to rock mechanical failure after volume reduction in the seams. The measured signals at the surface are therefore strongly affected by mechanical processes.More insight into causes and effects of involved energy transport processes is obtained by numerical simulation of the dynamic behavior of coal fires. Simulations show the inter-relation between release and transport of thermal energy in and around underground coal fires. Our simulation results show a time delay between the coal fire propagation and the observed appearance of the surface temperature signal. Additionally, the overall energy flux away from the burning coal seam into the surrounding bedrock is about 30-times higher than the flux through the surface. This is of particular importance for an estimation of the energy released based on surface temperature measurements. Finally, the simulation results also prove that a fire propagation rate estimated from the interpretation of surface anomalies can differ from the actual rate in the seam.