In vivo cell synchrony in the L1210 mouse leukaemia studied with 5-fluorouracil or 5-fluorouracil followed by cold thymidine infusion.

[3H]-TdR and [3]-udR labelling indices and mitotic indices were followed in tumour-bearing mice after application of either 5-fluorouracil (FU) alone or of FU followed by cold TdR infusion. With FU alone, accumulation of cells at the beginning of S was found, but there was no indication of a synchronous passage of the accumulated cells further round the cycle. When FU injection was followed by cold TdR infusion, a synchronous passage of the accumulated cells through the cycle was observed. However, there was a large variation in the response of individual mice to this treatment

Enhancement of the ferromagnetic order of graphite after sulphuric acid treatment

We have studied the changes in the ferromagnetic behavior of graphite powder and graphite flakes after treatment with diluted sulphuric acid. We show that this kind of acid treatment enhances substantially the ferromagnetic magnetization of virgin graphite micrometer size powder as well as in graphite flakes. The anisotropic magnetoresistance (AMR) amplitude at 300 K measured in a micrometer size thin graphite flake after acid treatment reaches values comparable to polycrystalline cobalt.Comment: 3.2 pages, 4 figure

Integrating Pastures into the Traditional Slash-and-Burn Cycle in Northeastern Pará, Brazil

A project to test possibilities to integrate pastures into the traditional slash-and-burn cycle of small farmers in the Bragantina region in northeastern Pará, Brazil, is presented. Whereas in practice the traditional grass-only pasture is managed separately from the crop/fallow cycle, two options for integration are tested: a Brachiaria humidicola pasture enriched with two bushy and one herbaceous legume, Cratylia argentea, Chamaecrista rotundifolia and Arachis pintoi, and a B. humidicola pasture allowing a controlled regrowth of secondary vegetation ( Capoeira ). The regeneration performance of these pastures for a subsequent cropping period is compared with plots of undisturbed regrowth of Capoeira concerning soil chemical and physical properties, botanical composition and biomass accumulation. To evaluate comparative pasture productivity and animal performance, a traditional grass-only pasture is included in the comparisons. The results will show if these alternative pastures lead to an ecologically more appropriate management concept for grasslands in the humid tropics

The response of the smallholder farm to the introduction of cattle in eastern amazon: the case of the Bragantina region.

Editado por Reinhard Lieberei, Helmut Bianchi, Vera Boehm, Christoph Reisdorff

Parallel Measurement and Modeling of Transport in the Darht II Beamline on ETA II

To successfully tune the DARHT II transport beamline requires the close coupling of a model of the beam transport and the measurement of the beam observables as the beam conditions and magnet settings are varied. For the ETA II experiment using the DARHT II beamline components this was achieved using the SUICIDE (Simple User Interface Connecting to an Integrated Data Environment) data analysis environment and the FITS (Fully Integrated Transport Simulation) model. The SUICIDE environment has direct access to the experimental beam transport data at acquisition and the FITS predictions of the transport for immediate comparison. The FITS model is coupled into the control system where it can read magnet current settings for real time modeling. We find this integrated coupling is essential for model verification and the successful development of a tuning aid for the efficient convergence on a useable tune. We show the real time comparisons of simulation and experiment and explore the successes and limitations of this close coupled approach

Experiences with Establishing Legumes as Part of a Ley Pasture in a Low-Input Farming System of the Eastern Amazon, Brazil

In the Eastern Amazon extensive pasture management by smallholders can result in degradation of grassland, leading to unproductive and abandoned agricultural areas (Dias-Filho, 2003). To avoid long and costly restoration of those areas, ley-systems with alternating cropping and pasture phases might offer a promising solution. The inclusion of N-fixing legumes is seen as a suitable method to improve soil fertility during the pasture phase. As mono-cultures seem not to be appropriate, given the phytodiverse climax vegetation in the humid tropics, a combination of various shrub and herbaceous legume species is proposed. Thus, this paper tests a grass-legume mixture to replace the fallow phase in the slash-and-burn agriculture practised by smallholders

From monotonous to enriched bushy pastures to replace the traditional smallholder management in north-eastern Pará, Brazil.

Editado por Reinhard Lieberei, Helmut Bianchi, Vera Boehm, Christoph Reisdorff