Developmental,Reproductive, and Demographic Alterations in Aquatic Wildlife: Establishing Causality between Exposure to Endocrine‐active Compounds (EACs) and Effects

This brief overview discusses the difficulty of demonstrating causal associations between exposure to endocrine active compounds (EACs) and the occurrence of developmental, reproductive, or demographic disturbances in aquatic wildlife. While for biological responses at the suborganism level correlational or causal evidence of an EAC etiology has been established in a number of cases, well proven examples of ecological consequences of endocrine disruption are rather few in number. The attribution of causality is complicated due to (i) lack of data on EAC exposure and bioaccumulation, (ii) lack of specific biomarkers and endpoints, together with insufficient knowledge on the mechanisms and conditions by which EAC‐induced disruption of endocrine functions translates into impaired organism development and reproduction, and (iii) insufficient understanding of the importance of species diversity in endocrine physiology and life histories for the consequences of endocrine disruption. Future research should address these gaps in our understanding of EAC exposure and effects, but additionally needs to pay more attention (i) to ecological determinants influencing the population‐level consequences of the endocrine disruption of developÍmental and reproductive functions, and (ii) to the use of epidemiological principles and approaches.     

Frontal substructures within the planetary boundary layer

A two-dimensional mesoscale model, extended by a TKE closure for the subgrid-scale terms and coupled with a soil model, is used to investigate the role of the Planetary Boundary Layer (PBL) for the development and the substructures of two different types of cold fronts. The effects of turbulent friction, large-scale (geostrophic) forcing and the diurnal variation of the terms of the surface energy balance (SEB) equation on the frontal development are studied by 10 different model runs. The ageostrophic cross-frontal circulation in the lowest two kilometres of a cold front results from friction as well as from large-scale forcing. The first one dominates the PBL processes and causes a special boundary-layer structure, which becomes apparent through the existence of seven characteristic zones defined for the x-z cross sections of potential temperature. The arrangement of these characteristic zones depends on the sense of rotation of the frictionally induced part of the ageostrophic circulation and hence on the direction of the along-front jet within the boundary layer. The daytime increase of the terms of the SEB equation for a midlatitude midsummer case leads to a strong enhancement of the frictionally induced cross-frontal circulation. The arrangement of the seven characteristic zones, however, is approximately conserved.     

Über den transport von Wolfram und den Absatz von Wolfram-Doppel-Oxiden in fluiden wässrigen LösungenThe transport of tungsten and the deposition of tungsten double oxides in fluid,aqueous solutions

The transportation of W in aqueous gas-phases at and above 500°C is examined using thermodynamic data. The transport of W is possible as fluoride and oxifluoride. The deposition of wolframite continues with decreasing temperature and pressure. The stabilities of wolframates in hydrothermal solutions are examined for temperatures up to 300°C with Eh-pH-diagrams, exchange reactions of wolframite with oxides, sulfides and dissolved ions. Fe₂WO₆ becomes stable against Fe₂O₃ + WO₃ above 126°C. At 300°C its range of stability begins at high pO₂ which is not realised in hydrothennal endogenous solutions. In consequence of the very low Gibbs energies of MgWO₄, CaWO₄ and BaWO₄, the minerals MgWO₄ and BaWO₄ should be more important than wolframite, if Mg and Ba coexist in solution together with W. Co and Ni also should be found as trace elements in wolframite, if Co and Ni were in solution in sufficiently high concentrations together with W.     

People of German descent in CIS States — areas of settlement,territorial autonomy and emigration

Until 1989 the ethnic Germans tended to live in Kazakhstan, Central Asia and South-West Siberia. Not only German but also Russian and Ukrainian residents in Kazakhstan and Central Asia have been induced to leave. In South-West Siberia attempts are beeing made to keep the ethnic Germans there. Two autonomous German districts have been established. The mass scale emigration to Germany has, however, affected these areas, too. That means that not only push factors are effective but also pull factors play a role. They concern the privileged immigrant status of Aussiedler in Germany. The economic damage suffered by Siberia on account of this kind of undifferentiated drain of workers and specialists puts whole economic regions in jeopardy. The German Home Office tried to support the re-establishment of the German Volga Republic which was dissolved by Stalin in 1941. Some German unprofessionally organised economic projects and severe diplomatic mistakes actually strengthened the nationalistic Russian opposition so that the reestablishment failed. An improvement of the ethnic Germans' perspectives in the CIS is only possible if Germany makes use of the tried and tested instruments of development aid and regional planning. German consulates and trade agencies should be opened in the Volga region, and in Siberia. It is necessary to establish a Siberian-German bank and Russian-German universities. A special programme should provide support for well-qualified people whose knowledge and skills are vital for a continuation of the ethnic Germans' economy and culture.     

An earlier explosion date for the Crab Nebula supernova

The Chinese first reported the Crab Nebula supernova on 1054 July 5. Ecclesiastical documents from the near east reported it in April and May of 1054. More than 33 petroglyphs made by Native Americans in the US and Mexico are consistent with sightings both before and after conjunction with the Sun on 1054 May 27. We found a petroglyph showing the new star close to Venus and the Moon, which occurred on 1054 April 12 and April 13, respectively. Collins et al., using the four historical dates, derived a light curve that is like that of a Type Ia supernova. The only remaining problem with this identification is that this supernova was near maximum light for 85 d, which is unlike the behavior of any known supernova.