Effect of temperature on embryonic and larval development of bream (Abramis brama L.)

Influence of water temperature on embryonic and larval development of bream (Abramis brama L.) was stdied. Eggs of bream were incubated at eight constant water temperatures between 13.2 and 26.8°C. The temperature of 21.1°C gave highest hatching success, with no abnormalities in the eleutheroembryos and lowest mortality observed between eyed egg stage and the time of hatching. Developmental rate increased with increasing temperature. Duration of embryonic development (y; hours) decreased with increasing incubation temperature (x; °C) according to the formula: y=910.1−65.88 x+1.318 x². Larvae were reared at eight constant temperatures ranging from 13.5 to 34.0°C. The instantaneous growth rate in wet weight increased with increasing test temperature from 13.5 to 29.9°C, and then decreased at higher temperatures. Individual growth of fish and biomass production rate were highest at 27.9°C. This temperature is considered optimal when food availability and photoperiod are no limiting factors.     

The use of heavy metal concentrations and dendrochronology in the reconstruction of sediment accumulation, Ma a Panew River Valley, southern Poland

Heavy metal concentrations were investigated in overbank sediments of the Mala Panew River, southern Poland. Samples were collected from seven vertical profiles located within channel infills of a 20th century floodplain at three sites, each up to 50 m wide. In each profile, 15–24 samples were collected and analysed for Ba, Cd, Cu, Pb, and Zn. Sequential extraction of these elements was carried out in the 0.063-mm fraction of selected samples. Additionally, the age of the oldest trees growing close to the profiles has been used to estimate the initiation of sediment accumulation there. Ba, Cu, and Pb, which occur mostly in less mobile, moderately reducible, and residual fractions, were used for sediment dating. Zn and Cd, which in 50–75% occur in the mobile exchangeable fraction, were not suitable for dating. Correlation of Ba, Cu, and Pb concentrations in vertical profiles with changes in the load of effluents discharged to the river showed abrupt changes in the thickness of the strongly polluted sediments across the floodplains. A comparison of the relative changes between heavy metal peaks in sediments of similar age in the different profiles suggests a variable rate of downward metal migration. In general, none of the heavy metals investigated seems to have been mobilised within the stratigraphic layers above the water table. In layers located at stratigraphically lower levels, the Zn and Cd peaks seem to migrate several centimetres to several decimetres down in the profile. In profiles inundated for several weeks every year, Zn and Cd, as well as the relatively less mobile Ba, Cu, and Pb, have migrated downward by several decimetres. The investigation shows that frequent fluctuations of the water table have blurred the original depositional metal patterns of metal concentrations within a period of less than 40 years.     

Preliminary Photometric Results for the 2003 Eclipse of Ee Cep

We report multicolour photometric observations of the 2003 eclipse of the long-period (5.6 yr) eclipsing binary EE Cep. Measurements were obtained with ten telescopes at eight observatories in four countries. In most cases, UBV(RI)_C broad band filters have been used. The light curve shape shows that the obscuring body is an almost dark disk around a low-luminosity central object. However, variations of the colour indices during the eclipse indicate that the obscuring body emits a considerable amount of radiation in the near infrared.     

Neotectonic Deformation of Pleistocene Deposits Along the Sudetic Marginal Fault,Southwestern Poland

The 160 km long Sudetic Marginal Fault (SMF) of Middle Silesia, southwestern Poland, is a main Alpine fault oriented NW–SE. This paper provides evidence of possible neotectonic activity in front of the SMF. The data are based on three exposures in the Roztoka–Mokrzeszow Graben near the city of Swidnica. Morphotectonic evidence in front of the SMF is also examined. Two sets of extensional deformation features are exposed and analysed. The main one includes gently inclined normal faults and flexures, with displacements in the bedrock of at least several metres. Based on the Quaternary stratigraphy of the region, the age of deformation is most probably Lower Saalian (Upper Pleistocene). The trigger for the deformation was probably the re-reactivation of the SMF and other faults due to the advance of the Lower Saalian Scandinavian ice-sheet into the Sudetic Mountains. The secondary deformation system includes sub-vertical, often conjugate faults with displacements up to 0·5 m superimposed on former structures. Its dominant normal faulting mode suggests an extensional stress regime that apparently coincides with the post-glacial glacioisostatic rebound. © 1997 John Wiley & Sons, Ltd.     

Brazil’s Financial Centers in the Twenty-first Century: Hierarchy,Specialization, and Concentration

The purpose of this article is to examine how the geography of Brazil’s financial centers changed since 2000 in terms of financial center hierarchy, specialization, and spatial concentration. To address these questions, we use data on employment and mergers and acquisitions in financial and business services, complemented with data on remuneration and bank assets. Our results show that São Paulo has consolidated its dominance as Brazil’s primary financial center, with market for corporate control as an important channel of this process. Rio’s decline as a financial center, which started more than fifty years ago, has continued into this century. At the same time, Brasília has emerged as the third most important financial center of Brazil. We document the recent dynamic of this territorial division of labor, with Rio’s specialization in insurance and Brasília’s dependence on government-owned banks. Finally, we show signs that Brazil’s financial center activities might be following an inverse U-shaped pattern whereby increasing geographical concentration is followed by its slow decline. Key Words: Brazil, concentration, financial centers, São Paulo, territorial division of labor.     

Human‐induced sedimentation patterns of a channelized lowland river

Channelization of the severely polluted Odra and Vistula Rivers in Poland induced intensive accumulation of fine‐grained deposits rich in organic matter and heavy metals. These sediments have been identified in vertical profiles in a narrow zone along river banks both in groyne‐created basins and on the floodplain. Grain size, organic matter, zinc (Zn), lead (Pb), copper (Cu) content and cesium‐137 (¹³⁷Cs) was used for sediment dating and, stratigraphy and chemistry have been diagnostic features for these deposits, named industrial alluvium. In the most polluted river reaches stabilized by bank reinforcements and groynes, 2‐m‐thick slack water groyne deposits are composed of uniform strata of polluted silts with organic matter content over 10%, Zn content over 1000 mg/kg and average Cu and Pb over 100 mg/kg. The average rate of sediment accretion in groynes is higher than on the floodplain and reaches 5 cm/yr. Stratification which appears at higher levels in the groyne fields and on the levees reflects a change from in‐channel to overbank deposition and is typified by dark layers separated by bright, sandy, and less polluted strata. Stratified, 4‐m‐thick, sediment sequences have been found in groyne fields of incised river reaches. The average rate of sediment accretion in these reaches is of the order of 5 cm/yr. In stable and relatively less polluted river reaches, vertical‐accretion organic deposits are finely laminated and the average rate of deposition amounts to a few millimeters per year. Investigations indicate that groyne construction favors conditions for long‐term storage of sediments at channel banks. For this reason, groynes should be considered as structures that efficiently limit sudden release of sediment‐associated heavy metals stored in channels and in floodplains of the historically polluted rivers. Copyright © 2014 John Wiley & Sons, Ltd.     

Foraging strategy of little auks under divergent conditions on feeding grounds

A dual foraging strategy (long versus short trips) has been described for some species of seabirds, such as petrels, albatrosses (Procellariiformes) and penguins (Sphenisciphormes). Such a strategy has recently been reported for little auks ( Alle alle ) from the central coast of west Spitsbergen, Svalbard. This has been explained as a response to poor trophic conditions close to the breeding colony, and better conditions further away (150 km). In the present study, we investigated the foraging strategy of little auks in Hornsund, southern Spitsbergen, during two seasons with contrasting oceanographic conditions. During 2004, foraging conditions for little auks were good: cold Arctic waters rich in profitable high-energy food were dominant in their feeding grounds. Conversely, during 2006 there was a great influx of warm Atlantic water in the feeding area, inducing poor foraging conditions. In both seasons we examined the pattern of foraging trip lengths automatically with a video camera (both adults from four nests in each year), and by direct non-stop observation of 20–54 individually marked birds. Our results showed that the dual strategy and the ratio of short and long trips were consistent, regardless of the conditions in the feeding grounds. This suggests that the strategy is inherent and may be crucial for the self-maintenance of adults.     

Altering Dissolved Oxygen to Determine Flow Conditions in Fractured Bedrock Wells

A new approach to locate transmissive fractures and decipher vertical borehole flow conditions in fractured crystalline bedrock wells is presented, which uses dissolved oxygen (DO) as a benign tracer. The method was tested in two fractured crystalline bedrock wells previously characterized by televiewer and flow meter logging under both ambient and stressed (slug test) conditions. The method entailed elevating wellbore DO concentrations by circulating water through showerheads or injection of compressed air. The DO dilution was used to locate inflowing fractures. Changes in the DO concentration with time were used to ascertain flow within the borehole and to locate outflowing fractures and stagnant zones. Flow rates were also estimated. Fractures detected by the method corresponded to those observed by televiewer logging and for the most part were comparable to flow meter results. Given the effectiveness, time‐efficiency and low cost, the method is a promising alternative to other methods currently in use to characterize transmissive fractures in wells.     

The effect of the distribution of measurement points around the node on the accuracy of interpolation of the digital terrain model

Contemporary land information systems allow the generation of models of numerical surfaces by applying a number of interpolation algorithms. The appropriate selection of measurement points included in the calculations is one of the key factors influencing the quality and accuracy of interpolation. Properly selected points contribute to improving the accuracy of the generated surface models and to shortening the computation process. This paper analyzes the effect of the location and density of measurement points on the accuracy of interpolation surfaces in view of the morphological differentiation of the generated models.