The effects of supplemental feeds containing different protein: Energy ratios on the growth and survival of Tilapia nilotica (Oreochromis niloticus) in brackishwater ponds

A research was conducted in thirty approximately 100 sq.m earthern ponds of the Brackishwater Aquaculture Centre (BAC), College of Fisheries, University of the Philippines, Leganes Iloilo from November 7, 1982 to March 7, 1983 to evaluate the effects of nine supplemental feeds containing different protein: energy ratios on the growth and survival of Tilapia nilotica in brackishwater ponds. Nine supplemental feeds formulated were with protein levels of 20%, 25%, and 30% each at three energy levels of 3,000 kcals; 3,500 kcals; and 4,000 kcals. There was a control treatment with no feeding so that mean weight gain growth rate, feed conversion rate, and survival were determined. Fish fingerlings were acclimated from 0-29 ppt. salinity before the experiment and 20% of fish in each treatment were sampled after every 30 days. Growth rates were significantly different and increased with increasing energy level at the 30% protein feeds but decreased at high energy levels in the 20% and 25% protein feeds. Feed conversion was significantly different due to interaction between protein and energy levels in the feeds, and was better at the 30:3,500 kcals feeds having a feed conversion of 1.55 g. Survival was not significantly differen

Imbibition, germination, and early seedling growth responses of light purple and yellow seeds of red clover to distilled water, sodium chloride, and nutrient solution

The seeds of red clover are heteromorphic and two color morphs can be visually recognized, light purple and yellow, resulting from heterozygosity and recessive homozygosity at two loci. Here, we report the responses of seed imbibition, seed germination, and early seedling growth of the two morphs to distilled water, sodium chloride, and complete nutrient solution. The sensitivity of red clover seeds to treatments increased with the stage of development in what seems to be a cumulative process. No differences were found in seed imbibition between morphs or between treatments. In seedling growth, on the contrary, treatments were always effective, but differences between morphs were only observed in seeds that were treated with nutrient solution, whereas in the intermediate stage of seed germination, the effects by treatments were observed together with the appearance of differences between morphs in distilled water and in the treatment by sodium chloride solution. Simultaneously, the superior performance of the yellow morph that was found in germination, which appears to be a trait stable across cultivars of red clover seeds, turned into a superior performance of the light purple morph in seedling growth

An exact solution to the Dirac equation for a time dependent Hamiltonian in 1-1D space-time

We find an exact solution to the Dirac equation in 1-1 dimensional space-time in the presence of a time-dependent potential which consists of a combination of electric, scalar, and pseudoscalar terms.Comment: Five page

Neuropathological investigations of three murine models of Huntington’s disease

Huntington’s disease (HD) is a purely genetic neurodegenerative disorder affecting approximately 1 in 10,000 people. It is most commonly associated with excessive involuntary movement, or chorea, combined with varying degrees of other motor, psychiatric and cognitive disturbances. Identification of the mutation in the HD gene prompted the generation of several transgenic mouse models. HD is but one of a family of at least 9 triplet repeat disorders, all of which exhibit protein aggregation by a similar mechanism. The understanding of one disease is therefore of importance to the understanding of them all. This thesis aims to be a comprehensive comparative study of three very different mouse models of HD elucidating the pathological changes that precede and accompany the disease process. The work described in this thesis presents a detailed account of a longitudinal study of the pathological changes that occur within the brains of founder generations of mice transgenic for exon 1 of the HD gene, containing a highly expanded CAG repeat, the R6 lines. I have determined the intracellular sites for deposition and accumulation of the mutant protein huntingtin (htt), within both the neurons and glia of the central nervous system. The progressive accumulation of additional proteins within these aggregates has been described. The temporal evolution and spatial distribution of the neuronal intranuclear inclusion (NII) was determined using both immunohistochemical and morphometric analyses. The cellular consequences resulting from the aggregation of mutant htt were also investigated. I have conducted a detailed morphometric analysis of neurones within the cerebral cortex, striatum and cerebellum throughout the period of protein deposition, until the eventual degeneration of these cells. The dendritic and somal changes resulting from the cellular disruption associated with these NII are also described. In a further series of experiments I have investigated the changes that occur in a novel model of HD, namely the conditional, doxycycline inducible double transgenic mouse, HD94 model. It was interesting to find that the same construct when differently manipulated in two mouse lines can produce such contrasting symptoms and pathology. This was highlighted by the comparison of immunohistochemical and morphometric analyses between the HD94 and the R6 lines, where the pattern of mutant protein deposition was found to vary significantly. Lastly I have studied a more genetically accurate murine model of HD, the HD80 ‘knock-in model’. These mice develop a pathology broadly similar to that of the R6 lines but markedly different to that of the HD94, and over a much longer time frame This detailed comparative analysis of the molecular and cellular pathology of three transgenic mouse models of HD provides new insights identifying novel and unique neuropathology and suggests new approaches for therapeutic treatments for this disease

Principles of valuing business travel time savings

OVERVIEW There are two approaches to valuing travel time savings to business people. The first is that which has formed the basis of UK policy for about 30 years, and which is set out in Section 2. This takes the value of travel time savings on employer’s business as equal to the gross wage rate plus an allowance for other costs that the employer saves. These might include such things as desk space, computer, tools, uniform, protective clothing, travel expenses. These were investigated in studies for the UK Department of the Environment around 1970 (Fullerton and Cooper, 1969; Rubashaw, Michali, Taylor and Key, 1969; Harrison, 1969; Harrison and Taylor, 1970; and Makrotest, 1970). The underlying rationale was that if employers were actually seen to be saving a certain amount of cost (through the gross wage and these various add-ons), then this was the value to them and, subject to any taxation related adjustments, should be the value to society. The approach is sometimes called ‘The Cost Saving Approach’, though it is also sometimes referred to as the ‘wage rate plus’ approach. Clearly, it was believed by the UK government that the economy was sufficiently competitive that average wage rates, for the employment groups concerned, reflected the value to employers. The approach can (but need not) be underpinned by appeals to the neoclassical theory of the firm and the labour market. This gives the equivalence of the marginal (revenue) product of labour to the marginal cost of employing labour, implying that a marginal minute saved will result in a marginal output increase valued at the wage rate for that minute. It is sufficient for this to be true on average, rather than for each individual employee involved. The process may also be ‘indirect’, such that employers receiving sufficiently big travel time savings, via their employees, might release resources into the labour market, where their value should be the marginal wage rate paid by employers for labour of this type. There is clearly room in this argument for small edge effects, but in general it does provide credible support for the Cost Saving Approach. However, its value is undermined by the possibilities it gives for objections to its assumptions, and this process ultimately leads most students of this area to at least wish to consider the more detailed ‘Hensher’ method to be considered in Section 3. This note then proceeds in Section 4 to review what AHCG did. Section 5 looks at the matter from the point of view of the employer. Finally, section 6 gives our conclusions

Values of time for road commercial vehicles

INTRODUCTION The purpose of this note is to review the report of Accent/HCG (1994), referred to here as AHCG, and other sources, and make recommendations regarding future official Values of Time for road commercial vehicles. This note starts by discussing current DTLR practice, as set out in its Transport Economics Note (TEN). Section 3 presents a digest of the AHCG findings. Section 4 looks at the findings of other studies. Although these are very mixed, carried out for a variety of purposes and presented in a variety of forms, they can serve as a partial check on the AHCG work. Section 5 presents interim conclusions

Tariff reform: an imperial strategy, 1903-1913

Historians of the Edwardian tariff reform movement have disagreed about its aims. This article examines the motivations of the leadership of the Tariff Reform League, which was by far the most influential organization in the tariff lobby. It argues that the League's leaders were more empire-minded than often allowed, and that it was the preferential tariff which they were most determined to promulgate and defend. Indeed, attempts by the Balfourite wing of the Unionist party to twist tariff reform away from its imperial origins were strongly resisted by the League, and the forces of protection within the organization were also carefully controlled. When the Tariff Reform League finally gave way on the issue of imperial preference in January 1913, it was not because it had suddenly ceased to be concerned about the unity of the empire. Rather, the widespread public hostility to the imposition of food duties showed no sign of diminishing, thus making it difficult to persuade a critical mass within the Unionist party that tariff reform was a politically viable strategy of imperial federation

Annual Report of the Netherlands to the European Commission on the implementation of Council regulation 812/2004 on cetacean bycatch

This report contains the results of the ongoing monitoring programme on the incidental bycatch of cetaceans in Dutch pelagic fisheries in 2009

The effect of soil moisture content on leaf extension rate and yield of perennial ryegrass

peer-reviewedThree experiments are described that were designed to evaluate the relationship between soil moisture and perennial ryegrass growth and leaf extension rate (LER) in loam or silt clay loam soil. When soil moisture was maintained at a range of proportions (0.5, 0.75, 1.0, 1.25) of field capacity (FC) in a pot experiment in a glasshouse, 0.75FC had consistently higher growth and LER than 0.5FC and, to a lesser extent, 1.25FC. The quadratic relationship between herbage growth and amount of water applied to maintain target field capacity, was stronger than for that between LER and the amount of water applied, with a maximum response at an application of about 2.5 L/m2 per day. In a microsward (soil depth of 30 cm in boxes 56 cm × 72 cm) trial inducing drought by withholding water for a range of durations resulted in a progressive decline in LER. When soil moisture content fell to about 0.4 of that of the consistently watered control LER was less than 0.1 of the control. However within one week of receiving water, even in the relatively severe drought treatment, LER was not significantly lower than the control treatment. LER was quadratically related to soil moisture content when soil was drying or after rewatering. In a further experiment on the microswards, reducing soil moisture content to about 0.18 g/g by limiting water in May-June resulted in a severe reduction in LER and growth rate and a decline in tillering rate. However, after application of the equivalent of 3 mm precipitation per day in late June, while soil moisture content remained relatively low (about 0.2 to 0.25 g/g soil), LER and herbage growth increased rapidly to as high as in consistently watered microswards. In a treatment in which soil moisture content eventually exceeded FC, LER and herbage growth declined with increase in excess above FC, concurring with findings in the steady state soil moisture experiment. Implications of the data for prediction of production from sown grass swards using temperate maritime grass-growth models are that: (1) during drought, when rainfall resumes, regrowth will be influenced more by amount of rainfallthan soil moisture content and (2) excess soil moisture should be taken into account, including effects of reduced nutrient uptake and post-anoxia stress

Commercial mariculture of Oreochromis niloticus using net cages

The culture of tilapia has a long history in Africa. Fossil remains of members of the genus have been found which are about 18 million years old (Fryer and Iles, 1972). Oreochromis niloticus was the subject of detailed observations in Egypt of 5,000 years ago. A bas relief of 2,500B.C. depicts tilapia being reared in ponds in Egypt. However, despite this long history the prolific nature of this fish results in very high populations in pond culture systems. Consequently small size fish are harvested. Several methods have thus been tried to control the excessive reproduction of tilapia in captivity with only partial success. This paper reports how large size tilapia especially O. niloticus averaging at least 150g per piece can be commercially produced using floating net cages in the marine environmen