The effects of dietary mannaoligosaccharides on cecal parameters and the concentrations of enteric bacteria in the ceca of salmonella-challenged broiler chicks

The ability of different enteric pathogens and coliforms to trigger agglutination of yeast cells (Saccharomyces cerevisiae, NCYC 1026) and a yeast cell wall preparation (MOS) was examined. Five of seven strains of Escherichia coli and 7 of 10 strains of Salmonella typhimurium and Salmonella enteritidis agglutinated MOS and Sac. cerevisiae cells. Strains of Salmonella choleraesuis, Salmonella pullorum, and Campylobacter did not lead to agglutination. Two strains that agglutinated MOS (S. typhimurium 29E and Salmonella dublin) and one nonagglutinating strain (S. typhimurium 27A) were selected as challenge organisms for in vivo studies in chicks under controlled conditions. In a series of three trials in which 3-d-old chicks were orally challenged with 10(4) cfu of S. typhimurium 29E, birds receiving 4,000 ppm of dietary MOS had reduced cecal S. typhimurium 29E concentrations (5.40 vs 4.01 log cfu/ g; P < 0.05) at Day 10. In a second series of three trials with S. dublin as challenge organism, the number of birds that tested salmonella positive in the ceca at Day 10 was less when MOS was part of the diet (90 vs 56%; P < 0.05). To test the effect of MOS on concentrations of bacteria that do not express Type 1 fimbriae, a challenge trial was conducted with S. typhimurium 27A. However, strain 27A did not colonize the birds sufficiently to evaluate whether MOS affected its cecal concentration. Mannanoligosaccharide did not significantly reduce the concentrations of cecal coliforms (P < 0.10) although they were numerically lower. It had no effect on cecal concentrations of lactobacilli, enterococci, anaerobic bacteria, lactate, volatile fatty acid, or cecal p

Towards robust experimental design for user studies in security and privacy

Background: Human beings are an integral part of computer security, whether we actively participate or simply build the systems. Despite this importance, understanding users and their interaction with security is a blind spot for most security practitioners and designers. / Aim: Define principles for conducting experiments into usable security and privacy, to improve study robustness and usefulness. / Data: The authors’ experiences conducting several research projects complemented with a literature survey. Method: We extract principles based on relevance to the advancement of the state of the art. We then justify our choices by providing published experiments as cases of where the principles are and are not followed in practice to demonstrate the impact. Each principle is a discipline specific instantiation of desirable experiment-design elements as previously established in the domain of philosophy of science. / Results: Five high-priority principles – (i) give participants a primary task; (ii) incorporate realistic risk; (iii) avoid priming the participants; (iv) perform doubleblind experiments whenever possible and (v) think carefully about how meaning is assigned to the terms threat model, security, privacy, and usability. / Conclusion: The principles do not replace researcher acumen or experience, however they can provide a valuable service for facilitating evaluation, guiding younger researchers and students, and marking a baseline common language for discussing further improvements

Histological and biochemical criteria for objective and early selection of grapevine cultivars resistant to Plasmopara viticola

Grapevine breeding is the most effective way to create cultivars resistant to downy mildew (Plasmopara viticola), and to reduce the number of fungicide applications. Four criteria, including histological and biochemical analyses, based on the level of different mechanisms of resistance to grapevine downy mildew, were tested on 42 different cultivars. Plantlets were artificially inoculated with downy mildew and the sporangia density was measured spectrophotometrically 6 d after infection. Callose synthesis in stomata and δ- and ε-viniferin levels at the site of infection were recorded 48 h after inoculation. These observations have allowed the 42 cultivars to be divided into 5 groups: very resistant (VR), resistant (R), less susceptible (LS), susceptible (S) and highly susceptible (HS). All 4 criteria have to be applied to assign the resistance level closer to field conditions. This method allows to rapidly evaluate the level of resistance of seedlings to downy mildew thereby leading to a reduction in duration  of the breeding program by several years.

“You can help people”: Adolescents’ Views on Engaging Young People in Longitudinal Research

We sought to discover adolescents’ thoughts about participation in longitudinal research and identify recruitment and retention strategies that were meaningful to them. We conducted seven focus groups with 10–15-year-olds in two large rural centers in New South Wales, Australia, and all focus groups were digitally recorded, transcribed, and analyzed. Adolescents discussed factors salient to their involvement in focus groups, as well as factors that may influence involvement in a longitudinal study. At the outset of the focus groups, adolescents had a positive view of “research,” but were reluctant to engage in research that involved biologic samples. Effective recruitment of adolescents requires an appreciation of motivators, and time and resources to extend potential participants’ understanding.Supported by Sydney Medical School Foundation

Effect of Pelleting Temperature on the Activity of Different Enzymes

The effects of different pelleting temperatures on the activity of cellulase, bacterial amylase, fungal amylase, and pentosanase were tested. Samples of a commercial barley-wheat-soybean diet containing different enzyme preparations were pelleted at 60, 70, 80, 90, and 100 C (pellet temperature measured at the die outlet) through a die containing holes 2.5 mm in diameter. Enzymatic analyses were conducted on either soluble substrates or by measuring the ability of the tested enzymes to decrease the viscosity of the diet. Measurements made on soluble substrates suggest that cellulase, fungal amylase, and pentosanase maintained activity when being pelleted at temperatures up to 80 C and bacterial amylase maintained activity at temperatures up to 90 C. Pentosanase and amylases showed little or no effect on the viscosity of the diet. Cellulase addition decreased the viscosity at all temperature levels, even after being pelleted at 90 and 100 C (P < 0.05). No cellulolytic activity was detected on the soluble substrate after these pelleting temperatures. Measurements on a soluble substrate might therefore not always reflect the true stability of a preparation because the ability of a carbohydrase to decrease the viscosity of the digesta is important to its effect in the gastrointestinal tract. Measurements on soluble substrates suggest that cellulase, fungal amylase, and pentosanase can be pelleted at temperatures up to at least 80 C and bacterial amylase up to 90 C without a considerable loss in analyzed activit

Hydrogenophaga defluvii sp nov and Hydrogenophaga atypica sp nov., isolated from activated sludge

Two Gram-negative, oxidase-positive rods (strains BSB 9.5T and BSB 41.8T) isolated from wastewater were studied using a polyphasic approach. 16S rRNA gene sequence comparisons demonstrated that both strains cluster phylogenetically within the family Comamonadaceae: the two strains shared 99·9 % 16S rRNA gene sequence similarity and were most closely related to the type strains of Hydrogenophaga palleronii (98·5 %) and Hydrogenophaga taeniospiralis (98·0 %). The fatty acid patterns and substrate-utilization profiles displayed similarity to the those of the five Hydrogenophaga species with validly published names, although clear differentiating characteristics were also observed. The two strains showed DNA–DNA hybridization values of 51 % with respect to each other. No close similarities to any other Hydrogenophaga species were detected in hybridization experiments with the genomic DNAs. On the basis of these results, two novel Hydrogenophaga species, Hydrogenophaga defluvii sp. nov. and Hydrogenophaga atypica sp. nov. are proposed, with BSB 9.5T (=DSM 15341T=CIP 108119T) and BSB 41.8T (=DSM 15342T=CIP 108118T) as the respective type strains

Skylab S-193 Radscat microwave measurements of sea surface winds

The S-193 Radscat made extensive measurements of many sea conditions. Measurements were taken in a tropical hurricane (Ava), a tropical storm (Christine), and in portions of extratropical cyclones. Approximately 200 scans of ocean data at 105 kilometer spacings were taken during the first two Skylab missions and another 200 during the final mission when the characteristics of the measurements changed due to damage of the antenna. Backscatter with four transmit/receive polarization combinations and emissions with horizontal and vertical receive polarizations were measured. Other surface parameters investigated for correlation with the measurements included sea temperature, air/sea temperature difference, and gravity-wave spectrum. Methods were developed to correct the microwave measurements for atmospheric effects. The radiometric data were corrected accurately for clear sky and light cloud conditions only. The radiometer measurements were used to recover the surface scattering characteristics for all atmospheric conditions excluding rain. The radiometer measurements also detected the presence of rain which signaled when the scattering measurement should not be used for surface wind estimation. Regression analysis was used to determine empirically the relation between surface parameters and the microwave measurements, after correction for atmospheric effects. Results indicate a relationship approaching square-law at 50 deg between differential scattering coefficient and wind speed with horizontally polarized scattering data showing slightly more sensitivity to wind speed than vertically polarized data