Refine
Year of publication
Document Type
- Article (1291) (remove)
Keywords
- gamma rays: general (41)
- gamma rays: galaxies (33)
- radiation mechanisms: non-thermal (27)
- galaxies: active (23)
- ISM: supernova remnants (18)
- acceleration of particles (18)
- cosmic rays (15)
- BL Lacertae objects: general (14)
- astroparticle physics (14)
- X-rays: stars (12)
Institute
- Institut für Physik und Astronomie (435)
- Institut für Biochemie und Biologie (242)
- Institut für Geowissenschaften (179)
- Institut für Chemie (90)
- Institut für Ernährungswissenschaft (57)
- Institut für Anglistik und Amerikanistik (44)
- Department Psychologie (31)
- Sozialwissenschaften (31)
- Department Sport- und Gesundheitswissenschaften (20)
- Strukturbereich Kognitionswissenschaften (18)
A necessary adjustment of protocol for use of DPC Coat-a-Count Total Testosterone assay with saliva
(1999)
Chromosomal assignment of the human gene for endosarcomeric cytoskeletal M-protein (MYOM2) to 8p23.3
(1999)
If an atom is able to exhibit macroscopic dark periods, or electron shelving, then a driven system of tow atoms has three types of these fluorescence types as a simple and easily accessible indivator of cooperative effects. As an examble, we study two dipole-interacting V systems by simulation techniques. We show that the durations of the two types of light periods exhibit marked sepatation-dependent oscillations and that they vary in phase with the real part of the dipole-dipole coupling constant.
Effect of parturition on levels of vitamins A and E and of ß-carotene in plasma and milk of mares
(1999)
In this brochure, Tristram argues that Standard English may be more indebted to the influence of 'Late British' than hitherto acknowledged by mainstream historical scholarship. By 'Late British' the native (or source) language of the about 2m language shifters in the wake of the Anglo-Saxon Conquest is meant who constituted the bulk of the native population of the island of Britain in the early middle ages. Although predictably, the influence of 'Late British' on Old English neither shows in the lexis of written Old English nor in its core grammar, it does show in the phonology (Peter Schrijver) and the inflectional syncretism of the Northern dialect texts. The influence of the interlanguage of the shifters only really surfaces in Middle English texts, after the diglossia between the language of the HIGH variety of Old English of the ruling elite and the LOW variety of the working population was discontinued under Norman rule. A number of grammatical features are listed in this brochure, which show that Present Day Standard English typologically sides with the Celtic languages, and with the Neo-Brittonic languages in particular, rather than with the other Continental Germanic languages. The brochure also calls for more research into this matter and in particular detailed investigations into the individual features mentioned.
The human p53 gene mutated at position 249 per se is not sufficient to immortalize human liver cells
(1999)
Unmixing hyperspectral data
(2000)
The growth rates of heterotrophic nanoflagellates (HNAN), mixotrophic cryptophytes, dinoflagellates and ciliates in field assemblages from Ace Lake in the Vestfold Hills (eastern Antarctica) and Lakes Fryxell and Hoare (McMurdo Dry Valleys, western Antarctica), were determined during the austral summers of 1996/1997 and 1997/1998. The response of the nanoflagellates to temperature differed between lakes in eastern and western Antarctica. In Ace Lake the available bacterial food resources had little impact on growth rate, while temperature imposed an impact, whereas in Lake Hoare increased bacterial food resources elicited an increase in growth rate. However, the incorporation of published data from across Antarctica showed that temperature had the greater effect, but that growth is probably controlled by a suite of factors not solely related to bacterial food resources and temperature. Dinoflagellates had relatively high specific growth rates (0.0057-0.384 h(-1)), which were comparable to Antarctic lake ciliates and to dinoflagellates from warmer, lower latitude locations. Temperature did not appear to impose any significant impact on growth rates. Mixotrophic cryptophytes in Lake Hoare had lower specific growth rates than HNAN (0.0029-0.0059 h(-1) and 0.0056-0.0127 h(-1), respectively). They showed a marked seasonal variation in growth rate, which was probably related to photosynthetically active radiation under the ice at different depths in the water column. Ciliates' growth rates showed no relationship between food supply and mean cell volume, but did show a response to temperature. Specific growth rates ranged between 0.0033 and 0.150 h(-1) for heterotrophic ciliates, 0.0143 h(-1) for a mixotrophic Plagiocampa species and 0.0075 h(-1) for the entirely autotrophic ciliate, Mesodinium rubrum. The data indicated that the scope for growth among planktonic Protozoa living in oligotrophic, cold extreme lake ecosystems is limited. These organisms are likely to suffer prolonged physiological stress, which may account for the highly variable growth rates seen within and between Antarctic lakes.
Mixotrophy is a widespread phenomenon among planktonic protists. It involves the combination of autotrophy and heterotrophy in varying degrees. Many phytoflagellate species ingest bacteria as a means of obtaining nutrients for photosynthesis or for supplementing their carbon budget under light limitation. Ciliates either sequester the plastids of their algal prey or harbour endosymbiotic algae. In the saline lakes of the Vestfold Hills and in Lakes Hoare and Fryxell in the McMurdo Dry Valleys the dominant phytoflagellates ingest bacteria, and there is evidence to suggest that during the winter months they lack chlorophyll and may become entirely heterotrophic. In Lake Fryxell phagotrophic pyhtoflagellates (cryptophytes) made a significant impact on bacterial production, removing up to 13% of the bacterial biomass day-1. These cryptophytes suffered predation from Plagiocampa (a ciliate), which appears to harbour them for a significant period before digesting them. We suspect that this may be equivalent to an intermediate stage in the evolution of mixotrophy. A significant number of the planktonic ciliates in Antarctic lakes were mixotrophic. The final evolutionary end point is the situation seen in Mesodinium rubrum, which now relies entirely on its cryptophycean endosymbiont and no longer ingests food. Mesodinium is the dominant ciliate in many of the saline lakes of the Vestfold Hills, which are of marine origin. It can reach abundances in excess of 60,000l-1 in Ace Lake, This ciliate is a ubiquitous member of the marine plankton worldwide and has successfully adapted to the lacustrine environment in Antarctica. The evidence suggests that among the survival strategies seen in Antarctic lake plankton, mixotrophy plays and important role among a number of the dominant protozoan species.