Photoperiodic manipulation and its use in the all year round production of Atlantic salmon, Salmo salar

The Atlantic salmon tSalmo safar) has two developmental processes which are clearly seasonal; smoltification is restricted to the spring and maturation to late autumn. In the farming industry the seasonality of juvenile production is primarily responsible for the seasonal production in market-sized fish. Both smoltification and maturation appear to be controlled by mechanisms timed by photoperiod. This thesis investigates the effects of photoperiod on smoltification and maturation. The performance of both out-of-season eggs and particularly smolts are closely examined and the possible application of photoperiod techniques in the industry discussed. Both potential SI and S2 parr were subjected to natural photoperiods or a range of artificial photoperiods under constant and ambient temperature conditions. S I and S2 smolts reared under natural photoperiods were transferred to sea water during April and May. A 2-3 month period of short days followed by a period of long days was observed to advance smoltification; 0+ and 1+ smolts were transferred to sea during December (4 month advance) and October (6 month advance), respectively. A 12 month seasonal photocycle delayed by 3 months delayed smoltification by 2 months. Out-of-season smolts were produced in January, March, April, May, June, July, October, November and December. All groups of out-of-season smolts exhibited the same growth potential as natural smolts. The different transfer date of out-of-season smolts therefore resulted in different harvest periods compared to natural smolts. The age at maturity of out-of-season smolts was positively related to the length of the seawater growing period prior to the completion of maturation. Out-of-season smolts exhibited increased maturation in association with an increased size (compared to natural smolts) for a particular time of year. These large maturing fish were generally harvested as superior salmon prior to flesh deterioration. Mortality during the first month in sea water was significantly higher in a number of out-of-season smolt groups compared to natural smolts. This was considered to be related to site-specfic environmental conditions rather than the smoltification process. Smoltification was also examined under constant photoperiods and a 4 week period of short daylengths. Dissociation and suppression of certain aspects of smoltification were observed. The different aspects of smoltification: the development of bimodality, hypoosmoregulatory ability, decrease in condition and smolt coloration appeared to be controlled by different independent mechanisms. The development of bimodality, hypoosmoregulatory ability and possibly coloration appeared to be controlled by independent endogenous rhythms. The decrease in condition factor, associated with the parr-smolt transformation required a period of short day length greater than 2 months followed by a period of long daylength. Smoltification and maturation were examined in salmon retained in constant 1DOC borehole water. Smolts held in fresh water grew steadily and matured producing eggs and sperm both in- and out-of-season. There was, however, a period of increased mortality after smoltification and egg quality was reduced especially in fish subjected to photoperiod manipulation. The salmon responded to photoperiodic manipulation. Abrupt changes in photoperiod advanced spawning by 12 weeks and a reciprocal seasonal photoperiod (6 month out of phase with a natural photoperiod) advanced spawning by 22 weeks. The maturation process in the Atlantic salmon would appear to be controlled by similar mechanisms to those described for the rainbow trout. Freshwater holding conditions appeared to decrease the age at maturity and reduce egg quality. The progeny of freshwater broodstock (FI generation) successfully completed smoltification and seawater transfer. Photoperiodic manipulation can be used to produce out-of-season smolts and eggs. Through the use of photoperiod, farms could increase and target production. This could remove the seasonality from the production cycle and help stabilise the pricing structure for market salmon

Crystal Cartography: Mapping Nanostructure with Scanning Electron Diffraction

Nanostructure describes the network of defective and distorted atomic structure existing on the nanoscale within materials. This nanostructure bridges the gap between idealised crys- talline structure and real materials, playing a deterministic role in tailoring physico-chemical properties, as well as providing a basis for mechanistic understanding of complex processes such as mechanical deformation and phase transformation. Characterising nanostructure, to develop understanding of materials, requires experimental techniques capable of probing the structure with spatial resolution on the order of nanometres and across regions of interest up to micrometres. Recent developments in electron microscopy, enabling the acquisition of numerous diffraction patterns in a spatially resolved manner, combined with modern computational power, provides a route to meet this need as developed in this work. Scanning electron diffraction (SED) involves the acquisition of a two-dimensional elec- tron diffraction pattern at each probe position in a two-dimensional scan of a specimen. An information rich 4-dimensional (4D-SED) dataset is obtained that can be analysed extensively post-facto using a wide-range of computational methods. The acquisition of such 4D-SED data from the specimen at numerous orientations may also enable the reconstruction of nanostructure in three-dimensions via tomographic methods. In this work, methods for the acquisition and analysis of 4D-SED data are developed and applied to reveal nanostructure in two and three-dimensions. These methods are applied to various prototypical characterisation challenges in materials science, particularly: strain mapping in two and three dimensions, revealing inter-phase crystallographic relationships, mapping grains in two-dimensional materials, and probing nanostructure in polyethylene

Towards the development of a multi-criteria decision support system for selecting stormwater best management practices.

Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001The aim of this dissertation was to develop a multi-criteria decision support system (MCDSS) to allow a specified manager to select with confidence one or many of these BMPs for a particular site. The principal design approach was a review of South African and international literature pertaining to stormwater management techniques, in particular BMPs. This information was formulated into a primary matrix using a rank-and-weighting method. The scores were then checked against the literature to ensure that they were reasonable, culminating in the initial MCDSS. The MCDSS was then provided with seven scenarios, described in the literature, and the output reviewed. Although, the MCDSS would select appropriately when given few criteria for selection when these were increased, inappropriate outcomes resulted. Consequently, weighting factors were assigned to each criterion. The MCDSS was further tested using all the selection criteria and the output deemed satisfactory. The MCDSS was then tested in a case study of the Town Bush stream catchment at eleven sites along the river network and the results were adequate. Taking into consideration the economic aspects of BMP implementation a need also arose for the sites to be allocated to certain authorities depending upon ownership or responsibility. The sites were prioritised depending on potential threat to property and lastly by the hydrological nature of the stream at each site. A stormwater plan for the study area was also proposed. Although the MCDSS was functioning adequately it was not without its limitations. Limitations included the use of drainage areas as a surrogate measure for peak discharge thus, not allowing the user to design a series of BMPs or treatment chain. A second limitation was that initially the BMPs were designed as offline systems where stormwater is managed before entering the channel but in this study they were used as inline systems. Hence the ultimate selection was biased towards those BMPs able to deal with large drainage areas. Recommendations for further improvement include the development of a surrogate measure for drainage area thus allowing the user to design a treatment chain of BMPs; testing the MCDSS in more diverse circumstances; developing a more comprehensive set of selection criteria; and developing a clearer priority-setting model as the one used was rather simplistic. In conclusion the MCDSS provides the user with a useful tool where the selection and implementation of BMPs no longer has to take place in an ad hoc manner

The formation of teaching identities among novice social science seminar tutors: A longitudinal study at the London School of Economics and Political Science

Research into academic identities has predominantly identified how social structures influence and constrain the agency of those involved in academic work (McLean, 2012). This reflects the predominantly sociological underpinnings of this research area (Clegg,200S). This study introduces psychological theory on identity formation to offer a complementary focus on individual agency and personal meaning making. This longitudinal case study investigates how five novice social science graduate teaching assistants (GTAs) formed identities as academic teachers during their first two years inservice. These tutors participated in the London School of Economics' Postgraduate Certificate in Higher Education (PGCertHE) during these two years. Changing identity positioning over time (Wetherell, 2001) was captured in tutors' writing using discourse analysis developed in the Discursive Psychological tradition (Edley, 2001). The findings of this study offer insight into academic identity formation. However, this study also contributes to research into the impact that participation on developmental courses, such as the LSE PGCertHE, can have on aspiring faculty as academic teachers. Impact has been assessed through pre- and post-testing (Gibbs & Coffey, 2004; Hanbury, Prosser, & Rickinson, 2008; Postareff, Lindblom-Ylanne, & Nevgi, 2007) and case studies (Butcher & Stoncel, 2012; Ho, Watkins, & Kelly, 2001). These studies have found impacts in terms of increased student focus and self-efficacy (Stes, Min-Leliveld, Gijbels, & Van Petegem, 2010). This study presents complementary findings. However, the longitudinal design offers an account of how the change identified in the larger, survey-ba~ed studies can come about. This shifting positioning is presented here in terms of initial 'idealism' becoming 'realism' with experience, but then leading to 'independence' as tutors developed 'pedagogic content knowledge' (Shulman, 1987)

Toll-like receptor expression in C3H/HeN and C3H/HeJ mice during Salmonella enterica serovar Typhimurium infection

Here, we have investigated the mRNA expression of Toll-like receptor 2 (TLR-2), TLR-4, and MD-2 in spleens and livers of C3H/HeN mice (carrying wild-type TLR-4) and C3H/HeJ mice (carrying mutated TLR-4) in response to Salmonella infection. During Salmonella infections, TLR-4 is activated, leading to increased TLR-2 and decreased TLR-4 expression

Paleoethnobotany of Buena Vista: a case study of ritual feasting in late Preceramic Peru

Title from PDF of title page (University of Missouri--Columbia, viewed on December 7, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Deborah M. Pearsall.Vita.Includes bibliographical references.Ph. D. University of Missouri--Columbia 2010.Dissertations, Academic -- University of Missouri--Columbia -- Anthropology.This project examines plant macroremains, phytoliths and starch remains recovered from special archaeological and architectural contexts at Buena Vista (11°43'51.72"S, 76°58'5.45"W) , an inland site in the lower Chilló́n Valley of Perú́. The primary goal of this work is to evaluate the evidence for feasting at a Late Preceramic site. The identification of feasting activities provides a way of examining the social practices, ritual and political, of the people who built Buena Vista. These results can be compared to other archaeological contexts in the Late Preceramic. Consequentially, this paleoethnobotanical study provides several corollary lines of investigation. The plant remains provide significant information on the agricultural component of subsistence in comparison to coastal sites of the time, as well as evidence for the use of special or specially prepared foods in a ritual context. The materials also add to our knowledge of interregional interaction that linked the coast of Perú to the northern and eastern lowlands