Climate induced human demographic and cultural change in northern Europe during the mid-Holocene.

The transition from hunter-gatherer-fisher groups to agrarian societies is arguably the most significant change in human prehistory. In the European plain there is evidence for fully developed agrarian societies by 7,500 cal. yr BP, yet a well-established agrarian society does not appear in the north until 6,000 cal. yr BP for unknown reasons. Here we show a sudden increase in summer temperature at 6,000 cal. yr BP in northern Europe using a well-dated, high resolution record of sea surface temperature (SST) from the Baltic Sea. This temperature rise resulted in hypoxic conditions across the entire Baltic sea as revealed by multiple sedimentary records and supported by marine ecosystem modeling. Comparison with summed probability distributions of radiocarbon dates from archaeological sites indicate that this temperature rise coincided with both the introduction of farming, and a dramatic population increase. The evidence supports the hypothesis that the boundary of farming rapidly extended north at 6,000 cal. yr BP because terrestrial conditions in a previously marginal region improved.

Polyploidy and hybridization as main factors of speciation: complex reticulate evolution within the grass genus Helictochloa.

To study the origin and evolution of naturally occurring polyploids, we performed phylogenetic analyses of nuclear ribosomal DNA spacers combined with molecular cytogenetics in 55 accessions of 27 taxa of the oat genus Helictochloa. A complex pattern of reticulate evolution was revealed with many diploid species and extensive polyploidy up to 20x. Altogether 11 groups of internal transcribed spacer (ITS) sequences can be distinguished. Sequences from 1-3 different ITS lineages were detected in polyploids. Cytogenetic data allow reconstruction of 8 basic monoploid chromosome sets. Six of these genomes occur in different combinations in the polyploid species. Two genomes are only found in diploids. Our sequence and karyological data highlight the occurrence of autopolyploidy and allopolyploidy, provide new information about the evolutionary history of taxa, and allow a more accurate systematic treatment of the concerned species. The geographical distribution of the 11 ITS lineages distinguished is highly structured and points to an origin of the genus in western Asia, presumably in grasslands like steppes or mountain steppes and meadows. The evolutionary basal lineages are of Asian, Minor Asian and east Mediterranean distribution and are present also in North America. The western and central parts of the Mediterranean and northern Europe harbor the modern lineages.

Contamination of arctic Fjord sediments by Pb-Zn mining at Maarmorilik in central West Greenland.

This study focuses on heavy metal contamination of arctic sediments from a small Fjord system adjacent to the Pb-Zn "Black Angel" mine (West Greenland) to investigate the temporal and spatial development of contamination and to provide baseline levels before the mines re-opening in January 2009. For this purpose we collected multi-cores along a transect from Affarlikassaa Fjord, which received high amounts of tailings from 1973 to 1990, to the mouth of Qaumarujuk Fjord. Along with radiochemical dating by (210)Pb and (137)Cs, geochemical analyses of heavy metals (e.g. As, Cd, Hg, Pb, and Zn) were carried out. Maximum contents were found at 12 cm depth in Affarlikassaa. After 17 years the mine last closed, specific local hydrographic conditions continue to disperse heavy metal enriched material derived from the Affarlikassaa into Qaumarujuk. Total Hg profiles from multi-cores along the transect clearly illustrate this transport and spatial distribution pattern of the contaminated material.

[Primary Zweymuller total hip arthroplasty for osteoarthritis secondary to congenital acetabular dysplasia].

OBJECTIVE: To evaluate the effectiveness of Zweymuller prothesis in replacing osteoarthritis secondary to congenital dysplasia of the hip. METHODS: From January 1996 to June 2000, Zweymuller prothesis was used to reconstruct 32 hips in 29 patients with congenital acetabular dysplasia(3 bilateral cases). All patients were female. According to the classification of Perner, 19 hips belonged to type I, 7 type II, 5 type III, and 1 type IV. The mean follow-up period was 27.5 months (6-53 months). The preoperative Harris hip score ranged from 25 to 59(average 44.5). RESULTS: The pain was completely relieved, and the Harris hip score ranged from 63 to 97(average 85). CONCLUSION: We consider that the Zweymuller total hip arthroplasty provides stable fixation of the cup in the presence of moderate acetabular dysplasia without structural bone grafting or cementing.

[Cementless implantation of Zweymueller-Endler total endoprosthesis of the hip. Clinical, radiologic and scintigraphic follow-up of 2 years]. / Zementfreie Implantation von Zweymüller-Endler-Totalendoprothesen der Hüfte--Klinische, röntgenologische und szintigraphische Verlaufs kontrolle über zwei Jahre.

Sixty-four patients with cementless Zweymueller-Endler total endoprostheses of the hip underwent follow-up postoperatively for 2 years. In 3 patients loosening or infection occurred. In 61 patients no complications were observed. However, in 74% of these patients increasing activity uptake at the tip of the shaft was found by scintigraphy. This was associated with hypertrophy of the corticalis and/or with a marrow cavity reaction, observed radiologically. The results show that scintigraphic evaluation of cementlessly implanted Zweymueller-Endler endoprostheses of the hip must be interpreted differently compared to isoelastic or to cemented prostheses.