Nitrate content and nitrogen loss in drainwater.

On cropped arable land, the nitrate content of drainage water showed a distinct maximum in spring (Mar.-May) and a minimum in autumn (Nov.). On grassland it was more constant during the year, except when N was applied in autumn or winter (liquid manure, f.y.m., liquid ammonia) when the situation was the same as for cropped arable land. An average content of 1-2 mg N/1. was found for grassland, and of 4-10 mg/1. for cropped arable land, depending on the clay content of the soil. From lysi-meter experiments it was found that on cropped arable land (350 mm drainage water per year) and from a soil profile of 100-125 cm with a clay content of 35% or more, little N was lost by leaching. On sandy soils (0-10% clay), however, about 60 kg N/ha could be lost yearly and 20% of the applied fertilizer N was leached out of the profile. On grassland, leaching losses depended on time of application of the N. A better distribution of the applied N during the growing season than on arable land and the high rate of N uptake by the grass greatly reduced the losses of applied N during the period Mar.-June, even on sandy soils. Later on, the losses could rise to a maximum of 40% for N applied in Nov.-A.G.G.H. (Abstract retrieved from CAB Abstracts by CABI’s permission

Streptococcal Receptor Polysaccharides: Recognition Molecules for Oral Biofilm Formation

<p>Abstract</p> <p>Background</p> <p>Strains of viridans group <it>streptococci </it>that initiate colonization of the human tooth surface typically coaggregate with each other and with <it>Actinomyces naeslundii</it>, another member of the developing biofilm community. These interactions generally involve adhesin-mediated recognition of streptococcal receptor polysaccharides (RPS). The objective of our studies is to understand the role of these polysaccharides in oral biofilm development.</p> <p>Methods</p> <p>Different structural types of RPS have been characterized by their reactions with specific antibodies and lectin-like adhesins. Streptococcal gene clusters for RPS biosynthesis were identified, sequenced, characterized and compared. RPS-producing bacteria were detected in biofilm samples using specific antibodies and gene probes.</p> <p>Results</p> <p>Six different types of RPS have been identified from representative viridans group <it>streptococci </it>that coaggregate with <it>A. naeslundii</it>. Each type is composed of a different hexa- or heptasaccharide repeating unit, the structures of which contain host-like motifs, either GalNAcβ1-3Gal or Galβ1-3GalNAc. These motifs account for RPS-mediated recognition, whereas other features of these polysaccharides are more closely associated with RPS antigenicity. The RPS-dependent interaction of <it>S. oralis </it>with <it>A. naeslundii </it>promotes growth of these bacteria and biofilm formation in flowing saliva. Type specific differences in RPS production have been noted among the resident streptococcal floras of different individuals, raising the possibility of RPS-based differences in the composition of oral biofilm communities.</p> <p>Conclusion</p> <p>The structural, functional and molecular properties of streptococcal RPS support a recognition role of these cell surface molecules in oral biofilm formation.</p

The reliability and usability of the Anesthesiologists’ Non-Technical Skills (ANTS) system in simulation research

Background: Non-technical skills (NTS) such as leadership and team work are important in providing good quality of care. One system to assess physicians’ NTS is the Anesthesiologists’ Non-Technical Skills (ANTS) system. The present study evaluates the ANTS system on the interrater reliability and usability for research purposes. Methods: Ten anesthesiologists and 20 anesthesiology residents performed two resuscitation scenarios (with and without the presence of distractors) in a simulation room with a full-scale patient simulator. The scenarios were videotaped. Two independent raters rated the NTS of the anesthesiologists using the ANTS system. The intraclass correlation coefficients (ICC) were calculated to determine the interrater reliability of both the total NTS score and the measured differences between the two scenarios. The raters filled out a questionnaire to obtain insights in the usability of the ANTS system for research purposes. Results: The ICC for the total score of the NTS was substantial (0.683), and the ICC of the elements varied between 0.371 for assessing capabilities and 0.670 for providing and maintaining standards. The intraclass correlation coefficient of measuring differences was fair (0.502). The raters judged the usability as good. Conclusions: The ANTS system was reliable for the total score and usable to measure physicians’ NTS in a research setting. However, there was variation between the reliability of the elements. We recommend that if the ANTS is used for research, a pilot study should determine elements not applicable or observable in the scenario of interest; these elements should be excluded from the study.</p