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Karim Gharbi Louise Matthews James Bron Ron Roberts Alan Tinch Michael Stear 《Journal of the Royal Society Interface》2015,12(110)
Sea lice threaten the welfare of farmed Atlantic salmon and the sustainability of fish farming across the world. Chemical treatments are the major method of control but drug resistance means that alternatives are urgently needed. Selective breeding can be a cheap and effective alternative. Here, we combine experimental trials and diagnostics to provide a practical protocol for quantifying resistance to sea lice. We then combined quantitative genetics with epidemiological modelling to make the first prediction of the response to selection, quantified in terms of reduced need for chemical treatments. We infected over 1400 young fish with Lepeophtheirus salmonis, the most important species in the Northern Hemisphere. Mechanisms of resistance were expressed early in infection. Consequently, the number of lice per fish and the ranking of families were very similar at 7 and 17 days post infection, providing a stable window for assessing susceptibility to infection. The heritability of lice numbers within this time window was moderately high at 0.3, confirming that selective breeding is viable. We combined an epidemiological model of sea lice infection and control on a salmon farm with genetic variation in susceptibility among individuals. We simulated 10 generations of selective breeding and examined the frequency of treatments needed to control infection. Our model predicted that substantially fewer chemical treatments are needed to control lice outbreaks in selected populations and chemical treatment could be unnecessary after 10 generations of selection. Selective breeding for sea lice resistance should reduce the impact of sea lice on fish health and thus substantially improve the sustainability of Atlantic salmon production. 相似文献
3.
Good requirements practices are neither necessary nor sufficient 总被引:2,自引:2,他引:0
4.
We demonstrate that alkali-halide salts, particularly potassium bromide, can reduce the photothermal emission (PTE) from single walled carbon nanotubes (SWNT). PTE is a prominent spectral feature in Raman spectroscopy when a near infrared laser is used to analyze a dark colored sample. We subsequently show that trapping salts inside SWNT and coating SWNT with the salt has a more pronounced impact on not only reducing PTE, but also enhancing the intensity of the Raman spectral features. The effect, which we have called nanotube enhanced Raman spectroscopy (NERS), has differences and similarities to the widely studied surface enhanced Raman spectroscopy (SERS). 相似文献
5.
Neil P. Soice Adrian C. Maladono Doreen Y. Takigawa Arlan D. Norman William B. Krantz Alan R. Greenberg 《应用聚合物科学杂志》2003,90(5):1173-1184
Selected aromatic amides were used to model the chemical reactivity of aromatic polyamides found in thin‐film composite reverse osmosis (RO) membranes. Chlorination and possible amide bond cleavage of aromatic amides upon exposure to aqueous chlorine, which can lead to membrane failure, were investigated. Correlations are made of the available chlorine concentration, pH, and exposure time with chemical changes in the model compounds. From the observed reactivity trends, insights are obtained into the mechanism of RO membrane performance loss upon chlorine exposure. Two chemical pathways for degradation are shown, one at constant pH and another that is pH‐history dependent. An alternative strategy is presented for the design of chlorine‐resistant RO membranes, and an initial performance study of RO membranes incorporating this strategy is reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1173–1184, 2003 相似文献
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D. M. Suckling R. W. Peck L. M. Manning L. D. Stringer J. Cappadonna A. M. El-Sayed 《Journal of chemical ecology》2008,34(12):1602-1609
Disruption of Argentine ant trail following and reduced ability to forage (measured by bait location success) was achieved
after presentation of an oversupply of trail pheromone, (Z)-9-hexadecenal. Experiments tested single pheromone point sources and dispersion of a formulation in small field plots. Ant
walking behavior was recorded and digitized by using video tracking, before and after presentation of trail pheromone. Ants
showed changes in three parameters within seconds of treatment: (1) Ants on trails normally showed a unimodal frequency distribution
of walking track angles, but this pattern disappeared after presentation of the trail pheromone; (2) ants showed initial high
trail integrity on a range of untreated substrates from painted walls to wooden or concrete floors, but this was significantly
reduced following presentation of a point source of pheromone; (3) the number of ants in the pheromone-treated area increased
over time, as recruitment apparently exceeded departures. To test trail disruption in small outdoor plots, the trail pheromone
was formulated with carnuba wax-coated quartz laboratory sand (1 g quartz sand/0.2 g wax/1 mg pheromone). The pheromone formulation,
with a half-life of 30 h, was applied by rotary spreader at four rates (0, 2.5, 7.5, and 25 mg pheromone/m2) to 1- and 4-m2 plots in Volcanoes National Park, Hawaii. Ant counts at bait cards in treated plots were significantly reduced compared to
controls on the day of treatment, and there was a significant reduction in ant foraging for 2 days. These results show that
trail pheromone disruption of Argentine ants is possible, but a much more durable formulation is needed before nest-level
impacts can be expected.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Diane M. Hopkins Alan D. Jackson Kenneth Oates 《Microscopy research and technique》1991,18(2):176-182
The standardisation of frozen hydrated bulk biological specimens using gelatin standards is described. The relationship between corrected elemental X-ray counts and ionic concentration was found to be linear, and minimum detectable limits for each element are stated. Variations in uncorrected standard curves were found to be due to changes in aluminium coating thickness. There was an inverse relationship between coating thickness and elemental X-ray counts. The factors causing this are discussed. To avoid errors arising from inconsistent aluminium thickness, experimental material should only be compared with standards of similar aluminium net counts. This can be achieved most easily by mounting and analysing specimen and standard together. 相似文献
10.
Ronald R. Delyser Sheila S. Thompson Jerry Edelstein Corinne Lengsfeld Albert J. Rosa Paul J. Rullkoetter Robert Whitman Margaret Whitt 《工程教育杂志》2003,92(3):269-273
A team of faculty members at the University of Denver changed the learning environment in key courses in the Department of Engineering from predominately teacher centered to student centered. Through this funded project new grading methods were implemented, classrooms were renovated and wired with studio layouts to facilitate learning, the Engineering Circuits Laboratory was rewired and instrumented for automated data acquisition and reporting, and two new pedagogical approaches were developed. At the onset of the project, six goals were established related to student learning. The introduction of industry standard hardware and software provided students with unprecedented hands‐on experience and project related activities stimulated faculty innovations in other current and future courses. Assessment results indicate that the new grading system improved the clarity of expectations for students before assignments were given resulting in increased reported motivation for learning in many courses. Even though course GPAs did not always reflect higher achievement on graded work, faculty members firmly believe that deeper understanding was achieved because more complex material was assimilated. 相似文献