The uptake and flow of C, N and ions between roots and shoots in Ricinus communis L. II. Grown with low or high nitrate supply

Seedlings of Ricinus communis L. cultivated in quartz sand weresupplied with a nutrient solution containing either 0.2 molm^–3     

Carbon-specific phytoplankton growth rates: a comparison of methods

Measurements of biomass and growth rate of two axenic algalcultures were carried out using three different methodologicalapproaches: the specific ¹⁴C-labelling of chlorophyll a, [³H]adenineincorporation into DNA and net organic carbon assimilation.Time-course experiments revealed that the specific activitiesof chlorophyll a were significantly higher than the specificactivity of total algal carbon in six of seven experiments.When the specific activity of chlorophyll a is used to calculatethe carbon biomass and growth rate, the carbon biomass of thealgae will thus be underestimated and the specific growth ratewill be too high. Determination of growth rates from incorporationof [³H]adenine gave lower values than those obtained from netorganic carbon assimilation and from ¹⁴C incorporation intochlorophyll a. Problems with adenine saturation are suggested.When [³H]adenine is used to measure growth rates in dense algalcultures, additions of >1 µM [³H]adenine are oftenrequired to maximally label the extracellular and intracellularadenine pools and hence DNA.     

The first fossil Dipsocoridae found in the early Eocene amber of France (Hemiptera: Heteroptera)

Cryptostemma eocenica sp. nov., the first fossil representative of the family Dipsocoridae (Heteroptera: Dipsocoromorpha), is described from Eocene amber of France on the basis of a single macropterous female. The specimen is very ‘modern’ in appearance, demonstrating the remarkable morphological stability of this family since 53 Ma. Its generic affinities are difficult to estimate because the modern genera are mostly separated by male genitalia or female internal structures.     

A novel HLA-DRB1-DR2 allele associated with HLA mistyping

This work was supported by a research grant from the Federal Ministry of Research and Technology (BMFT/DFVLR) 01 VM 8608/9.     

Brief International Cognitive Assessment for MS (BICAMS): international standards for validation

ABSTRACT: An international expert consensus committee recently recommended a brief battery of tests for cognitive evaluation in multiple sclerosis. The Brief International Cognitive Assessment for MS (BICAMS) battery includes tests of mental processing speed and memory. Recognizing that resources for validation will vary internationally, the committee identified validation priorities, to facilitate international acceptance of BICAMS. Practical matters pertaining to implementation across different languages and countries were discussed. Five steps to achieve optimal psychometric validation were proposed. In Step 1, test stimuli should be standardized for the target culture or language under consideration. In Step 2, examiner instructions must be standardized and translated, including all information from manuals necessary for administration and interpretation. In Step 3, samples of at least 65 healthy persons should be studied for normalization, matched to patients on demographics such as age, gender and education. The objective of Step 4 is test-retest reliability, which can be investigated in a small sample of MS and/or healthy volunteers over 1-3 weeks. Finally, in Step 5, criterion validity should be established by comparing MS and healthy controls. At this time, preliminary studies are underway in a number of countries as we move forward with this international assessment tool for cognition in MS.