Variability of the respiratory surface area of pupae in Simulium monticola species group (Diptera, Simuliidae)

The variability of the respiratory surface area of Simulium monticola Friederichs, 1920 and Simulium argyreatum Meigen, 1838 pupae was studied in detail. 333 pupae from Western Carpathian Mts. were investigated. According to the tubercles on thorax and head of the pupa of S. monticola, two morphological forms were distinguished (S. monticola 1 and S. monticola 2). Both were studied separately. In any species or form respectively we measured the lengths of all respiratory filaments and basal trunks, the widths of the basal trunks, the widths of the filaments on their proximal and distal end and the widths 0.25 mm from the proximal end. In all species (forms) differences in the size of the respiratory surface area between the first (April – June) and the second generation (August – October) were found. In S. monticola 1 the mean real respiratory surface area was significantly (p < 0.001) larger in spring (3.67 mm²) than in summer (2.19 mm²). In S. monticola 2 the mean real respiratory surface area was 3.45 mm² in spring, and it was significantly larger in females than in males (p = 0.034). In S. argyreatum the mean real respiratory surface area was 2.80 mm² in spring 2001 while in different summer generations it was significantly smaller: 1.58 mm² in 1999, 1.84 mm² in 2000 and 2.12 mm² in 2001. All these groups differed significantly from each other. Regression models could explain 64.5% (power model) of the real respiratory surface area in S. monticola 1 and 19.9% (various models) of the real respiratory surface area in S. argyreatum due to the variability of the adult size.     

Influence of atmospheric pressure variations on measurements made with Sharpe and Worden gravimeters

Summary The paper deals with the influence of the atmospheric pressure variations on Sharpe gravimeters CG 2 No. 226 and 280 and on the Worden gravimeter No. 978, equipped with a thermostat.Dedicated to RNDr. Jan Pícha, CSc., on his 60th Birthday     

Important flare events in variations of the auroral electrojet index

Summary The effects of solar proton flares and enhanced solar activity, indicated by intensive radio bursts in the decimetre range, on the Auroral Electrojet (AE) Index at the time these events occurred, are investigated. A significant increase in the level of the AE index was observed after the occurrence of these events.     

Refraction anomalies determined from meteorological sounding measurements

Summary The paper outlines some new approaches to discovering refraction anomalies using available meteorological data which characterize the vertical condition of the atmosphere in the neighbourhood of an observatory. Due to the limited number of data and the methods of processing, the resultant refraction anomalies refer to only a part of the atmosphere, approximately 10 km in height.     

Origin of siderite mineralisation in Petrova and Trgovska Gora Mts., NW Dinarides

The Petrova and Trgovska Gora Mts. (Gora=Mountain) are Variscan basement units incorporated into the northwestern Dinarides during the Alpine orogeny. They host numerous siderite-quartz-polysulphide, siderite-chalcopyrite, siderite-galena and barite veins, as well as stratabound hydrothermal-replacement ankerite bodies within carbonates in non-metamorphosed, flysch-like Permo-Carboniferous sequences. The deposits have been mined for Cu, Pb, Ag and Fe ores since Medieval times. Fluid inclusion studies of quartz from siderite-polysulphide-quartz and barite veins of both regions have shown the presence of primary aqueous NaCl?CaCl₂±MgCl₂?H₂O±CO₂ inclusions. The quartz-sulphide stage of both regions show variable salinities; 2.7–26.2 wt% NaCl eq. for the Trgovska Gora region and 3.4–23.4 wt% NaCl eq. for the Petrova gora region, and similar homogenisation temperatures (100–230°C). Finally, barite is precipitated from low salinity-low temperature solutions (3.7–15.8 wt % NaCl equ. and 115–145°C). P-t conditions estimated via isochore construction yield formation temperatures between 180–250°C for the quartz-sulphide stage and 160–180°C for the barite stage, using a maximum lithostatic pressure of 1 kbar (cc. 3 km of overburden). The sulphur isotope composition of barite from both deposits indicates the involvement of Permian seawater in ore fluids. This is supported by the elevated bromium content of the fluid inclusion leachates (120–660 ppm in quartz, 420–960 ppm in barite) with respect to the seawater, indicating evaporated seawater as the major portion of the ore-forming fluids. Variable sulphur isotope compositions of galena, pyrite and chalcopyrite, between ?3.2 and +2.7‰, are interpreted as a product of incomplete thermal reduction of the Permian marine sulphate mixed with organically- and pyrite-bound sulphur from the host sedimentary rocks. Ore-forming fluids are interpreted as deep-circulating fluids derived primarily from evaporated Permian seawater and later modified by interaction with the Variscan basement rocks. ⁴⁰Ar/³⁹Ar data of the detrital mica from the host rocks yielded the Variscan age overprinted by an Early Permian tectonothermal event dated at 266–274 Ma. These ages are interpreted as those reflecting hydrothermal activity correlated with an incipient intracontinental rifting in the Tethyan domain. Nevertheless, 75 Ma recorded at a fine-grained sericite sample from the alteration zone is interpreted as a result of later resetting of white mica during Campanian opening/closure of the Sava back arc in the neighbouring Sava suture zone (Ustaszewski et al. 2008).     

Motion of a Meteoroid Released from an Asteroid

Evidence of asteroid surface features as regolith grains and larger boulders implies resurfacing possibility due to external forces such as gravitational tidal force during close planet encounters. Motion of a meteoroid released from an asteroid in the gravitational fields of the asteroid and the Earth is modeled. We are interested mainly in a distance between the meteoroid and the asteroid as a function of the time. Applications to Itokawa and some close approaching NEAs are presented.     

Schroeter's ratios for Martian craters: Radar results

Schroeter's ratios (ratios of the rim volume to the apparent volume) are determined for a sample of 29 large, degraded Martian craters selected from the Goldstone Mars radar altimetry data. On the average, the values of the calculated Schroeter's ratios are about two orders of magnitude smaller than the same ratios for fresh lunar craters. This indicates a severe rim volume deficit in degraded Martian craters and it provides an additional support to the notion of a widespread resurfacing of intercrater plains on Mars. Schroeter's ratios for degraded craters could provide a semi-quantitative measure of the effects of the modification processes that had been active on Mars and on the other planetary bodies.     

Solar magnetic field distribution and geomagnetic activity

Summary Regularities in the solar background magnetic field distribution are described and some of their specific patterns and their structures are studied. The influence of the solar differential rotation on the behaviour of Magnetic Active Longitudes is demonstrated. The origin of some specific details different in both polarities is discussed. The relation of this longitudinal solar magnetic field distribution to the longitudinal distribution of the daily geomagnetic character figures C9 is investigated. Some correlational characteristics are given. The specific Index of Geomagnetic Recurrence is estimated and the changes of its values in time are demonstrated.

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Site formation processes in loess areas: A case study from moravany-žakovska,western slovakia

The site of Moravany-Žakovska in western Slovakia is situated in a loessic terrain and is dated to the end of the Late Glacial Maximum. This article shows the importance of analyzing the 0.01-0.1 mm fraction to interpret the sedimentological environment and a number of measured anthropogenic indices, such as burnt quartz grains, charcoal, radiolarite chips, microflakes, and microfragments of bone. Analysis of the profile of the site through time reveals the relationship between occupational levels and phases of slope wash that occurred during wetter climatic episodes; these are separated by phases of aeolian sedimentation. At the same time, analysis of anthropogenic indices in this size fraction permitted the identification of occupational levels, including those not recorded by macrofinds. Analysis of anthropogenic indices in horizontal exposures enabled the identification of latent settlement structures such as hearths, areas of radiolarite processing, zones where mineral dyes were prepared, and other structures not recorded by macrofinds.