Serial population extinctions in a small mammal indicate Late Pleistocene ecosystem instability

in Proceedings of the National Academy of Sciences of the United States of America (2012), 109(50), 20532-20536

The Late Pleistocene global extinction of many terrestrial mammal species has been a subject of intensive scientific study for over a century, yet the relative contributions of environmental changes and ... [more ▼]

The Late Pleistocene global extinction of many terrestrial mammal species has been a subject of intensive scientific study for over a century, yet the relative contributions of environmental changes and the global expansion of humans remain unresolved. A defining component of these extinctions is a bias toward large species, with the majority of small-mammal taxa apparently surviving into the present. Here, we investigate the population-level history of a key tundra-specialist small mammal, the collared lemming (Dicrostonyx torquatus), to explore whether events during the Late Pleistocene had a discernible effect beyond the large mammal fauna. Using ancient DNA techniques to sample across three sites in North-West Europe, we observe a dramatic reduction in genetic diversity in this species over the last 50,000 y. We further identify a series of extinction-recolonization events, indicating a previously unrecognized instability in Late Pleistocene small-mammal populations, which we link with climatic fluctuations. Our results reveal climate-associated, repeated regional extinctions in a keystone prey species across the Late Pleistocene, a pattern likely to have had an impact on the wider steppe-tundra community, and one that is concordant with environmental change as a major force in structuring Late Pleistocene biodiversity. [less ▲]

Serial translocation via circular intermediates underlies color-sidedness in cattle.

Scientific conference (2012, May 04)

Series episcoporum Ecclesiae Catholicae Occidentalis, t. I

in Moyen Age (Le) (1984)

Series production of thixoformed steel parts

in Solid State Phenomena (2006), 116-117

In recent years several attempts were made to transfer the thixoforming technology of steel parts into industrial applicable processes. This paper gives an overview about the progress of a European ... [more ▼]

In recent years several attempts were made to transfer the thixoforming technology of steel parts into industrial applicable processes. This paper gives an overview about the progress of a European consortium that established a fully automated thixoforming process for the series production of automotive steel parts. Due to the multi-faceted nature of this technology, problems concerning the development of suitable steel grades and tool materials as well as the development and application of an inductive heating system, a handling unit and of a complex forming tool had to be solved. Besides the development of adapted steel grades and the inductive heating, the handling of the semi solid billets plays a special role because during the manipulation of the parts from the heating station into the tool a loss of heat is unavoidable. Furthermore, scaling of the parts must be prevented. By means of a fully automated process line existing constraints were reduced and the forming process is kept reproducible. Improved silicon nitride composites have been developed as a tool material, which show good mechanical properties in combination with an acceptable chemical stability at the occurring process temperatures as well as in contact with semi solid steel. Basing on the practical experience a comparison of the thixoforming technology to existing processes and an outlook for the ftiture are, given. [less ▲]

Serine Beta-Lactamases and Penicillin-Binding Proteins

in Annual Review of Microbiology (1991), 45

Serine-Type D-Ala-D-Ala Peptidases and Penicillin-Binding Proteins

in Methods in Enzymology (1994), 244

Le serment de Paneb et de son fils (P Salt 124, V° 1,5-8)

in Bulletin de la Société Égyptologique de Genève (1991), 15

Les Serments de Strasbourg et les débuts de l'histoire du français

in Niederehe, H.-J.; Schlieben-Lange, B. (Eds.) Die Frühgeschichte der romanischen Philologie: von Dante bis Diez (1987)

A seroepidemiological study of human cysticercosis in West Cameroon

in Tropical Medicine & International Health [=TM & IH] (2003), 8(2), 144-149

We studied the occurrence of human cysticercosis in 4993 individuals from three rural communities of Menoua Division, West Province of Cameroon. Circulating antigens of Taenia solium metacestodes were ... [more ▼]

We studied the occurrence of human cysticercosis in 4993 individuals from three rural communities of Menoua Division, West Province of Cameroon. Circulating antigens of Taenia solium metacestodes were detected in 0.4%, 1.0% and 3.0% of the serum samples taken in Bafou, Bamendou and Fonakekeu, respectively, and examined using a monoclonal antibody-based enzyme-linked immunosorbent assay. This test detects only carriers of living cysticerci and gives thus a good idea of the presence of Active cysticercosis. The percentage of persons infected with cysticercosis increased with age. Twenty-two of the 34 seropositives underwent computed tomography (CT) of the brain. Thirteen of them were CT-scan positive, which shows that neurocysticercosis was present in 59.1% of the tested seropositive persons. No living cysticerci were detected among 20 seronegative people. About 20.6% of the seropositives had a history of or current taeniasis against only 1.9% of the seronegatives. Based on these figures and on the data on porcine cysticercosis (prevalence: 11%) and human taeniasis (prevalence: 0.13%) collected in the same region, we conclude that T. solium cysticercosis is an endemic, but overlooked public health problem in West Cameroon. [less ▲]

Serological and cutaneous testing of bovine tuberculosis with the A60 antigen complex from Mycobacterium bovis, strain Calmette-Guérin

in Preventive Veterinary Medicine (1995), 23

A60, a major thermostable macromolecular antigen complex of Mycobacterium bovis strain Calmette-Guerin (BCG), is immunodominant in tuberculosis and able to elicit both humoral and cellular immune ... [more ▼]

A60, a major thermostable macromolecular antigen complex of Mycobacterium bovis strain Calmette-Guerin (BCG), is immunodominant in tuberculosis and able to elicit both humoral and cellular immune reactions in infected hosts. A60-based ELISA and cutaneous tests have been used, in conjunction with the PPD-based skin reaction, in a control group of healthy animals, and in a herd including tuberculous animals. Cutaneous testing with A60 yielded results comparable with those with PPD: both were negative with control cattle and positive with infected animals. Moreover, comparative cutaneous testing with avian tuberculin yielded similar results with PPD and A60. When animals from the infected herd were tested with both avian and bovine sensitins, 54% of cattle were diagnosed as fully positive, 26% suspect, and 20% negative. Serological analysis with the A60-ELISA of part of the infected herd yielded 74% positive, 21% suspect and 5% negative results. Thus, positivity was 74% for serological analysis and 54% for cutaneous testing, whereas positive plus suspect results were 95% for serological analysis and 80% for cutaneous testing. It can be concluded that A60 can be used in place of PPD for cutaneous testing in cattle, and that the diagnostic value of the A60-ELISA is superior to that of the PPD-cutaneous test. [less ▲]