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Ruminants are recognised to suffer from Cu-responsive disorders. Present understanding of Cu transport and metabolism is limited and inconsistent across vets and veterinary professionals. There has been much progress from the studies of the 1980s and early 1990s in cellular Cu transport and liver metabolism which has not been translated into agricultural practice. Cu metabolism operates in regulated pathways of Cu trafficking rather than in pools of Cu lability. Cu in the cell is chaperoned to enzyme production, retention within metallothionein or excretion via the Golgi into the blood. The hepatocyte differs in that Cu-containing caeruloplasmin can be synthesised to provide systemic Cu supply and excess Cu is excreted via bile. The aim of the present review is to improve understanding and highlight the relevant progress in relation to ruminants through the translation of newer findings from medicine and non-ruminant animal models into ruminants.
The present study investigated nutritional programming in Atlantic salmon to improve utilisation of a vegetable-based diet. At first exogenous feeding, fry were fed either a marine-based diet (Diet Mstimulus, 80% fishmeal (FM)/4% fish oil (FO)) or a vegetable-based diet (Diet Vstimulus, 10% FM/0% FO) for 3 weeks. Subsequently, all fish were then fed under the same conditions with a commercial, marine-based, diet for 15 weeks and thereafter challenged with a second V diet (Diet Vchallenge, 10% FM/0% FO) for 6 weeks. Diploid and triploid siblings were run in parallel to examine ploidy effects. Growth performance, feed intake, nutrient utilisation and intestinal morphology were monitored. Fish initially given Diet Vstimulus (V-fish) showed 24 % higher growth rate and 23 % better feed efficiency compared with M-fish when later challenged with Diet Vchallenge. There was no difference in feed intake between nutritional histories, but increased nutrient retentions highlighted the improved utilisation of a V diet in V-fish. There were generally few significant effects of nutritional history or ploidy on enteritis scores in the distal intestine after the challenge phase as only V-triploids showed a significant increase (P<0·05) in total score. The data highlighted that the positive effects were most likely a result of nutritional programming and the ability to respond better when challenged later in life may be attributed to physiological and/or metabolic changes induced by the stimulus. This novel study showed the potential of nutritional programming to improve the use of plant raw material ingredients in feeds for Atlantic salmon.
Three integrity measures are introduced: contamination, channel suppression and program suppression. Contamination is a measure of how much untrusted information reaches trusted outputs; it is the dual of leakage, which is a measure of information-flow confidentiality. Channel suppression is a measure of how much information about inputs to a noisy channel is missing from the channel outputs. And program suppression is a measure of how much information about the correct output of a program is lost because of attacker influence and implementation errors. Program and channel suppression do not have interesting confidentiality duals. As a case study, a quantitative relationship between integrity, confidentiality and database privacy is examined.
This paper has the strictly practical objective of devising procedures for managing Equity portfolios to the best advantage.
First, Modern Portfolio Theory, (MPT) which has been developed over the last 35 years with just this objective, is critically examined; from a study of the history of MPT and of its philosophy, principles and practices, the authors conclude that this discipline makes no contribution whatever to improving the performance.
1.1 In the paper “Improving the Performance of Equity Portfolios” by Clarkson and Plymen (presented to the Institute of Actuaries on 25th April 1988) the authors concluded that Modem Portfolio Theory methods made no contribution whatever to improving the performance of equity portfolios and suggested that attention should be paid instead to the application of fundamental analysis, which—if carried out by skilled and experienced analysts—should lead to higher expected returns. The only practical application of techniques related to Modem Portfolio Theory appeared to be in the area of Index Funds, where it is desired to track the performance of a chosen index as closely as possible.
The paper describes the construction and application of a general price model based on the hypothesis that prices within an ordinary share market are in equilibrium after all participants have acted on their interpretation of the information available to them. The model can be regarded as a space time co-ordinate system in that all the attributes which affect the price of a share are described in terms of numerical scales and all the measurable changes over time in the equilibrium position correspond to changes in the position of a surface in 4-dimensional space.
The application of the model to the U.K. ordinary share market is described. In particular, it is shown how the relative performance of a share can be resolved into various short-, medium- and long-term components, each of which can be studied in isolation using the model as a frame of reference. In the light of this practical experience, a detailed description of the price formation process within an ordinary share market is obtained.
Since the principles underlying the practical application of the model have virtually nothing in common with the Modern Portfolio Theory methods currently in use in the United States, an attempt is made to reconcile the differing conceptual approaches. The empirical results of the market equilibrium model indicate that the theoretical foundations of Modern Portfolio Theory are somewhat insecure, and it is therefore concluded that the market equilibrium model offers the better scientific framework for the management of ordinary share portfolios.
This paper investigates what general form of price model is required to represent a market that is in equilibrium under switching action and describes how a special case of this general price model can be applied to the gilt-edged market, with particular emphasis on long-dated stocks. Applications of the mathematical model are then developed in a form that could be used by a life office or pension fund for the management of a portfolio of long-dated British Government stocks. Finally, a comparison is made between conventional yield curve methods of analysis and methods based on this mathematical model.
The electric conductivity of metals has been observed to change very greatly at their melting point, the resistance being in many cases nearly doubled when the metal is fused. The experiments recorded in the following communication originated in an attempt to investigate more fully into this fact. The metals chosen for the first observations were tin and lead, both of which have their melting points at temperatures that can be readily obtained.
The object of the following experiments, which were suggested by Professor Chrystal, was to determine the relative values of the intensity of the horizontal component of magnetic force, due to a current flowing in the coils of the Helmholtz galvanometer, for different parts of its field.
The central parsec of our Galaxy hosts not only a supermassive black hole, but also a large population of young stars (age <6 Myr) whose presence is puzzling given how inhospitable the region is for star formation. The strong tidal forces require gas densities many orders of magnitude higher than is found in typical molecular clouds. Kinematic observations of this young nuclear cluster show complex structures, including a well-defined inner disk, but also a substantial off-disk population. Spectroscopic and photometric measurements indicate the initial mass function (IMF) differs significantly from the canonical IMF found in the solar neighborhood. These observations have led to a number of proposed star formation scenarios, such as an infalling massive star cluster, a single infalling molecular cloud, or cloud-cloud collisions. I will review recent works on the young stars in the central parsec and discuss connections with young nuclear star clusters in other galaxies, such as M31, and with star formation in the larger central molecular zone.
A FIMAG Working Party was set up in 1989 to consider the stochastic investment model proposed by A. D. Wilkie, which had been used by a number of actuaries for various purposes, but had not itself been discussed at the Institute. This is the Report of that Working Party. First, the Wilkie model is described. Then the model is reviewed, and alternative types of model are discussed. Possible applications of the model are considered, and the important question of ‘actuarial judgement’ is introduced. Finally the Report looks at possible future developments. In appendices, Clarkson describes a specific alternative model for inflation, and Wilkie describes some experiments with ARCH models. In further appendices possible applications of stochastic investment models to pension funds, to life assurance and to investment management are discussed.
The Viséan sequence at East Kirkton was deposited in a shallow lake, set within a richly vegetated landscape formed of volcanic cones a few hundred metres high. There was little volcanic activity, however, while the lake existed, and the many tuff horizons within the sequence were washed in during weathering. The lake may have been generally cool, though of unusual water chemistry, as a result of which the spherulitic East Kirkton Limestone precipitated. At times, however, water temperatures may have risen sharply through localised hot-spring activity; both factors deterred ‘normal’ aquatic life.
The bulk of the preserved biota consists of plants (permineralisations and compressions) and dominantly land-living animals, including the oldest terrestrial tetrapods (amphibians and reptiliomorphs), large terrestrial-aquatic eurypterids, the first harvestman and rare millipedes. All these animals lived close to the lake, in a fire-prone forest dominated by gymnosperms and pteridosperms.
At a late stage in the history of the lake, deposition of spherulitic limestones was replaced by black shales, bearing a ‘standard’ Oil-Shale fish fauna, suggesting that the isolated lake had linked with a larger fish-bearing water body. This is coupled with a shift to a lycopod-dominated flora and may indicate a climatic change to wetter conditions. Finally the lake silted up with tuff, ending an existence of only a few tens of thousands of years.
Calyptaulax brongniartii (Portlock) from the Caradocian Bardahessiagh Formation, Pomeroy, Northern Ireland is redescribed. Equivalent material from Scottish horizons (Balclatchie and Ardwell groups) is regarded as belonging to separate populations. Campbell's system of notation is used to describe variation in the arrangement and number of lenses in the eye. The most closely related species is C. strasburgensis (Ulrich & Delo) from the Edinburg Limestone of Virginia, U.S.A.
To estimate the sensitivity and specificity of computed tomography used for the detection of extranodal spread of metastatic head and neck squamous cell carcinoma, by experienced head and neck radiologists.
Materials and methods:
Participants had undergone a neck dissection for head and neck squamous cell carcinoma, together with computed tomography scanning prior to surgery (accessible for reporting). Computed tomography images were independently examined by two experienced head and neck radiologists. Nodal involvement by squamous cell carcinoma and the presence or absence of extranodal spread were recorded. Results were compared to the histological specimen. The sensitivity, specificity and positive predictive value of using computed tomography for the detection of nodal involvement and presence or absence of extranodal spread were estimated, and 95 per cent confidence intervals were calculated.
Results and analysis:
The study analysed 149 neck dissections. When using computed tomography to detect the extranodal spread of head and neck squamous cell carcinoma, radiologists A and B had sensitivities of 66 and 80 per cent, specificities of 91 and 90 per cent, and positive predictive values of 85 and 87 per cent, respectively.
The sensitivity and specificity of radiological detection of extranodal spread from head and neck squamous cell carcinoma is not well reported in the literature. Accuracy of reporting improves in the hands of experienced head and neck radiologists. This finding has clinical implications for surgical planning and adjuvant therapy requirements.