182 research outputs found
Implications for the environment of using adaptive feeding systems in the cage culture of Atlantic salmon
The use of adaptive feeding systems to deliver feed remotely to Atlantic salmon (Salmo salar) cages has the potential to improve the localised environment through a reduction in particulate waste. This can be achieved through improved growth and lower Feed Conversion Ratio (FCR). The aim of this project was to assess whether adaptive feeding systems confer any environmental benefit at salmon farms through by comparing two fish farm sites, one that uses a Computer Aided System (CAS) adaptive feeding system (AKVAsmart UK limited, Inverness, Scotland) (Portavaide fish farm) and one using hand feeding (Rubha Stillaig).
This investigation comprised of 3 elements: 1) a comparative assessment of the quantity and nutrient composition of particulate waste material emanating from the cages; 2) collection of benthic samples plus a video survey along transects at each
site including a reference station, with an analysis of differences in benthic fauna, sediment grain size and sediment nutrient composition; and 3) comparison of the distribution of waste under each feeding regime using a GIS-based modelling
approach.
Particulate waste was collected via sediment traps. Uneaten feed was caught in only 3 out of 184 separate collections and thus no estimate of feed loss for each feeding system could be made. Samples were analyzed for total solids (TS), faecal solids (FS), faecal carbon (FC), faecal nitrogen (FN) content and faecal sedimentation rate (FSR). The highest deposition occurred under the cages and decreased with increased distance from the cage centre. Maximal deposition of TS at Portavadie was higher than at Rubha Stillaig when feed was included, although average TS, FS, Fe and FN per tonne of production did not significantly vary between sites. Carbon sedimentation rate was analyzed using regression analysis and a General Linear Model Factorial ANOVA on faecal waste only and showed no significant differences between sites and, therefore, no difference between feeding methods .
There were no differences observed in the diversity and abundance of benthic species under the two feeding systems. By the end of the production period all stations out to 25m from the cage edge were dominated by Capitella capitata at both sites, this species proving a useful indicator of the impact of nutrient deposition. The analysis suggested that Heteromastus filiformis and Corophium sp. provided useful indicators of the onset of nutrient enrichment. Measurement of carbon and nitrogen levels and particle size in sediment showed no difference between sites. Variations between sites in species abundance and diversity and sediment carbon and nitrogen levels reflected the different sediment conditions prevalent at the start of the sampling period. Univariate and multivariate analysis showed there was no difference in species diversity and abundance between the sites as a result of using adaptive feeding systems.
Horizontal cage movement, measured at up to 10m, reduced the predicted settlement under the cage by 23% and 11 % for feed and faecal distribution respectively. There was no significant difference in the predicted settlement of waste particulates under adaptive and hand feeding. The GIS model prediction of carbon flux (g C m-2 15-days-1) was validated for faecal settlement using sediment trap data where predictions agreed well with observations from Portavadie fish farm, with an accuracy of ± 53.1 % when all stations were included, improving to ± 27.6% when deposition under the cage was excluded.
Overall, the approaches used did not identify specific differences between sites that used adaptive feeding and hand feeding methods. The growth period using the adaptive feeding system was approximately nine weeks shorter than under hand feeding, however, which could be used constructively to increase the fallowing period whilst maintaining current levels of production. This would benefit the localised benthos by increasing the time available for recovery before further production takes place and thus the CAS Adaptive Feeding System could be used as part of a broader sustainable farming strategy for fish cultur
Learning-based text mining in analysis of free-text responses to the (2013) Wales Cancer Patient Experience Survey (WCPES): findings and future applications
Exploration and analysis of free-text comments from the 2013 Wales Cancer Patient Experience Survey (WCPES)
Exploration and analysis of free-text comments from the 2013 Wales Cancer Patient Experience Survey (WCPES)
Pleistocene Bats (Late Irvingtonian and Late Rancholabrean) from Nuckolls and Sherman Counties, Nebraska
We document rare finds of fossil bats from two localities representing the Pleistocene epoch in southern and central Nebraska, Albert Ahrens locality (No-104, late Irvingtonian age, Middle Pleistocene), Nuckolls County, and Litchfield (Sm-102, late Rancholabrean age, latest Pleistocene), Sherman County. The Albert Ahrens local fauna with strong boreal influence has produced two bats, Lasiurus cf. borealis and Cf. Myotis sp. The Litchfield local fauna, also showing a strong boreal influence, has yielded two bats, Eptesicus fuscus and Cf. Myotis, among a diverse Pleistocene fauna of small vertebrates and a pollen record indicating a boreal mixed conifer and deciduous woodland, contrasting with the grassland and mixed grass prairie of the area in historic times prior to anthropogenic conversion. The vertebrate fauna from the Litchfield site can be assigned to the Rancholabrean land mammal age based on the presence of Bison, on faunal correlation, and on several extralimital taxa of small mammals. The fossil bat taxa are widespread in North America and still extant in Nebraska today; their glacial stage occurrences in a nonkarstic (caveless) region is consistent with previous interpretations of the Albert Ahrens and Litchfield local faunas as indicating cool equable climates and wooded parkland environments. These are the first bats to be reported from each of the respective paleofaunas
Learning-based text mining in analysis of free-text responses to the (2013) Wales Cancer Patient Experience Survey (WCPES): findings and future applications
Exploring experiences of cancer care in Wales - a thematic analysis of free-text responses to the 2013 Wales Cancer Patient Experience Survey (WCPES).
Objectives: To provide the first systematic analysis of a national (Wales) sample of free-text comments from cancer patients, to determine emerging themes and insights regarding experiences of cancer care in Wales.
Design: Thematic analysis of free-text data from a population-based survey.
Setting and Participants: Adult patients with a confirmed cancer diagnosis treated within a three month period during 2012 in the seven Health Boards and one trust providing cancer care in Wales.
Main outcome measures: Free-text categorised by theme, coded as positive or negative, with ratios. Overarching themes are identified incorporating comment categories.
Methods: 4,672 respondents (of n=7352 survey respondents) provided free-text comments. Data was coded using a multistage approach; (1) coding of comments into general categories (e.g. Nursing, Surgery etc.), (2) coding of sub-categories within main categories (e.g. Nursing Care, Nursing Communication etc.), (3) cross-sectional analysis to identify themes cutting across categories (4) mapping of categories/sub-categories to corresponding closed questions in the WCPES data for comparison.
Results: Most free-text respondents (82%, n 3818) provided positive comments about their cancer care, with 49% (n=2313) giving a negative comment (ratio: 0.6:1, negative-to-positive). 3172 respondents (67.9% of free-text respondents) provided a comment mapping to one of four overarching themes: communication (n=1673, 35.8% free-text respondents, a ratio of 1.0:1); waiting during the treatment and/or post-treatment phase (n=923, 19.8%, ratio: 1.5:1); staffing and resource levels (n=671, 14.4% ratio: 5.3:1); speed and quality of diagnostic care (n=374, 8.0%, ratio: 1.5 : 1). Within these areas, constituent sub-themes are discussed.
Conclusions: This study presents specific areas of concern for cancer patients, and reveals a number of themes present across the cancer journey. While the majority of comments were positive, analysis reveals concerns shared by significant numbers of respondents. Timely communication can help to manage these anxieties, even where delays or difficulties in treatment may be encountered.
Strengths and limitations of the study:
• Provides further detail on closed measures in population-based survey.
• Indicates area of concern not addressed by closed measures.
• Volume of comments and ratios of negative to positive comments in specific areas indicate areas of particular concern
Qualitative assessment of initial biofouling on fish nets used in marine cage aquaculture
A short communication which assesses the process of initial development of biofilms on nets used for fish culture in marine systems. Settlement follows a pattern of succession through conditioning, bacteria and diatoms with associated Extracellular Polymeric Substance (EPS) and other microscopic algae and fauna. Initial settlement appears to accelerate further settlement
Bending Properties of Nickel Electrodes for Nickel-Hydrogen Batteries
Recent changes in manufacturing have resulted in nickel-hydrogen batteries that fail prematurely by electrical shorting, This failure is believed to be a result of a blistering problem in the nickel electrodes. In this study the bending properties of nickel electrodes are investigated in an attempt to correlate the bending properties of the electrode with its propensity to blister. Nickel electrodes from three different batches of material were tested in both the as-received and impregnated forms. The effects of specimen curvature and position within the electrode on the bending strength were studied, and within-electrode and batch-to-batch variations were addressed. Two color-imaging techniques were employed to differentiate between the phases within the electrodes. These techniques aided in distinguishing the relative amounts of nickel hyroxide surface loading on each electrode, thereby relating surface loading to bend strength. Bend strength was found to increase with the amount of surface loading
- …