Regulation of the resistance and resilience of periparturient ewes to infection with gastrointestinal nematode parasites by dietary supplementation

Control of gastrointestinal nematode (GIN) parasites has traditionally been based on the premise of chemotherapeutic control with the resultant consequence being the development of anthelmintic resistance by GIN. An alternative premise to the management of GIN parasites is to improve the resistance and resilience of sheep to GIN infection by manipulating the nutritional environment at key periods of a sheep's life. One key period, is the periparturient phase in the reproductive cycle when ewes experiences a temporary loss, or diminution, of immunity to GIN parasites. This phase is associated with an increased requirement for both metabolisable energy (ME) and metabolisable protein (MP). The increased requirement being greater for MP. The loss of immunity to GIN is associated with a diminished cell-mediated immune response in the gut mucosa, the magnitude of which can be regulated by protein nutrition, or more specifically the supply of MP. Experimental studies that have increased MP supply, in housed and grazing periparturient ewes, have demonstrated significant improvements in resistance to GIN infection. Positive gut immune responses to an increased MP supply are believed to occur because the increased MP supply counters the combined pathological consequences of GIN infection per se and the host's immune response, namely a net loss of amino acids. Susceptibility to GIN infection in the periparturient ewe may also be a function of a low priority for use of MP toward immune function but evidence from young animals suggests a disproportionate partitioning of amino acids to the gastrointestinal tract during GIN infection. It is proposed that the priorities for use of MP that predispose the ewe to GIN infection are altered following infection to favour a gut immune response. Despite being under the regulation of MP supply and genetic selection, the loss of immunity during the periparturient period cannot be fully restored by either approaches suggesting that other unidentified factors are involved in the periparturient loss of immunity. Resilience to GIN infection is responsive to both ME and MP supply. The practice of supplementing periparturient ewes to increase MP and ME supply, in order to enhance resistance and resilience to GIN infection, is gaining favour with graziers within some regions of Australia. Other benefits (e.g. increased reproductive rates) arise from such supplementation strategies that improve the cost effectiveness of this approach

Is operationalising natural capital risk assessment practicable?

Financial institutions are indirectly exposed to risks associated with the impacts and dependencies on natural capital and ecosystem services of the companies that they invest in, lend to, and insure. This is particularly true for banks lending to agriculture: a sector with both significant impacts and critical dependencies on natural capital. Bank lending is a vital source of new finance for the sector, which is essential to achieve sustainable intensification targets. Yet current credit decision-making practice is still based on conventional financial and management indicators, lacking any systematic assessment of natural capital risks, especially those associated with dependencies. Operationalising natural capital risk assessment requires practicable indicators and data to evaluate the most material natural capital risks for a given sub-sector and geography, but it is unclear to what extent these are available. We assess the practicability of natural capital dependency risk indicators and data sources for a critical case study of Australian sheep production. We find that at least moderately practicable indicators and data sources are available to assess the 11 major dependency risks that are material for this industry. Challenges remain in determining risk thresholds for most indicators, and quantifying risk impacts on profitability. © 2021 Elsevier B.V

Barrier formation at metal/organic interfaces: dipole formation and the Charge Neutrality Level

The barrier formation for metal/organic semiconductor interfaces is analyzed within the Induced Density of Interface States (IDIS) model. Using weak chemisorption theory, we calculate the induced density of states in the organic energy gap and show that it is high enough to control the barrier formation. We calculate the Charge Neutrality Levels of several organic molecules (PTCDA, PTCBI and CBP) and the interface Fermi level for their contact with a Au(111) surface. We find an excellent agreement with the experimental evidence and conclude that the barrier formation is due to the charge transfer between the metal and the states induced in the organic energy gap.Comment: 7 pages, Proceedings of ICFSI-9, Madrid, Spain (September 2003), special issue of Applied Surface Science (in press

Depth-Resolved Subsurface Defect Detection in Ceramics Using Optical Gating Techniques

Components made from advanced ceramics materials find widespread use in many industrial and military applications. However, the presence of defects in the bulk and on the surface of the ceramic parts can alter their operation and lead to a reduced lifetime or a catastrophic failure. These defects may include various inclusions, inherent powder defects, poorly distributed second phase material, as well as voids and cracks. They can be introduced at each stage of the manufacturing process. Near-surface defects are particularly critical in many applications since the stresses in this region of the ceramic component are greatest during the operation. These flaws may be intrinsic to the bulk material or can be introduced in the final stages of fabrication (e.g. machining, grinding and polishing). Additionally, in composite ceramics defects can appear as a delamination of internal layers. Because the potential market for ceramic components is so large, a considerable effort has been put into developing non-destructive evaluation (NDE) techniques to detect flaws at various stages of the manufacturing process [1–5]

Taking the tool analogy seriously: Forms and naming in the cratylus

Copyright © The Author(s) 2014. Published by Cambridge University Press. It has been suggested that the so-called tool analogy passage of Plato's Cratylus presents us with a moderate linguistic naturalism that can stand or fall independently of the more unpalatable etymological and mimetic theories advanced later in the dialogue. This paper offers a reading of the tool analogy which argues that Socrates' employment of Forms (and in particular Species-Forms), together with a careful distinction between the types of knowledge associated with making and using tools, aims to establish a radical linguistic naturalism that constrains the intrinsic properties of names. This should be clear if we take Socrates' claim seriously that names are tools: tools in general can only function successfully if they exhibit the relevant structural, compositional and (to some extent) material properties. Since Socrates claims that names are a class of tools and not merely like tools in some respects, as many have supposed, then what holds for tools in general must also hold for names

p70S6 Kinase Phosphorylates AMPK on Serine 491 to Mediate Leptin's Effect on Food Intake

SummaryThe PI3K-AKT, mTOR-p70S6 kinase and AMPK pathways play distinct and critical roles in metabolic regulation. Each pathway is necessary for leptin's anorexigenic effects in the hypothalamus. Here we show that these pathways converge in an integrated phosphorylation cascade to mediate leptin action in the hypothalamus. We identify serine491 on α2AMPK as the site of convergence and show that p70S6 kinase forms a complex with α2AMPK, resulting in phosphorylation on serine491. Blocking α2AMPK-serine491 phosphorylation increases hypothalamic AMPK activity, food intake, and body weight. Serine491 phosphorylation is necessary for leptin's effects on hypothalamic α2AMPK activity, neuropeptide expression, food intake, and body weight. These results identify an inhibitory AMPK kinase, p70S6 kinase, and demonstrate that AMPK is a substrate for mTOR-p70S6 kinase. This discovery has broad biologic implications since mTOR-p70S6 kinase and AMPK have multiple, fundamental and generally opposing cellular effects that regulate metabolism, cell growth, and development

Estimation of allantoin flux using continuous infusion of [14C]allantoin: Sensitivity to plasma loading with unlabelled allantoin

Allantoin net flux through the plasma allantoin compartment was determined in sheep given a roughage diet by means of a continuous infusion of [4,5-14C]allantoin for 17 h. Unlabelled allantoin was infused intravenously during the last 7 h of the tracer infusion to increase the allantoin flux by approximately 75%. When unlabelled allantoin was infused, the specific radioactivity of allantoin in plasma and urine declined exponentially to approach a lower plateausome 2–3 h later. The estimate of net flux during the infusion of unlabelled allantoin, estimated from blood plasma and urine, was on average 79 and 90% of expected values. Expected values of allantoin net flux during infusion of unlabelled allantoin were calculated as the sum of allantoin net flux pre-loading plus the known rate of infusion of the allantoin load. It is probable that endogenous allantoin synthesis was decreased by the infusion of allantoin: allosteric inhibition of uricase appears a plausible explanation for this observation, and for lower estimates of net flux. Appearance of labelled allantoin-C in ruminal or blood bicarbonate was negligible. Our results indicate that net flux of allantoin through blood plasma is a good predictor of the entry rate of allantoin into the primary compartment and should be a better predictor of rumen microbialoutflow than urinary allantoin excretion. However, measurements of allantoin-specific radioactivity, during continuous infusion, should be taken after a period of 24 h, at which time the true plateau specific radioactivity value of allantoin in plasma would be attained

Investigating the effect of gastrointestinal nematodiasis in Merino sheep on the Northern Tablelands of New South Wales and implications for Integrated Parasite Management

On the Northern Tablelands of NSW, gastrointestinal nematodiasis imposes significant constraints to sheep production. The overall aim of this thesis was to quantify this production loss and evaluate the extent to which it can be ameliorated by integrated parasite management approaches. The general hypothesis tested in this work was that gastrointestinal nematode infection (i.e. worms) present on commercial sheep properties in the Northern Tablelands of NSW induces significant production loss and that worm control utilising Integrated Parasite Management in Sheep (IPM) would reduce this loss and the overall economic impact of worms. ... This research has quantified the biological and economic impact of worms on commercial farms on the Northern Tablelands of NSW in the largest and most comprehensive study of its kind to date. It has shown it to be higher than previous estimates which is primarily due to increased commodity prices. The work has also clearly demonstrated the benefits of Integrated Parasite Management in Sheep in reducing both worm-induced mortality and the overall economic impact of gastrointestinal nematode infection. It is hoped that the information presented in this thesis will ultimately support an increased adoption by industry of sustainable worm control programs

Ecology of the free-living stages of 'Haemonchus contortus' in a cool temperate environment

Current understanding of the ecology of 'Haemonchus contortus' is incomplete and seen as an impediment to effective control of the worm in summer rainfall regions, where outbreaks are common and can result in significant stock mortality. Although there has been a wealth of published research on the effects of temperature on free-living development of 'H. contortus', our level of understanding of how moisture in the micro- and macro-environments influences development to infective larvae on herbage is considerably lower. The current state of knowledge of the free-living ecology of 'H. contortus' is reviewed in Chapter 2, with a particular focus on research findings since the 1970s. Knowledge gaps are highlighted, and a proposal made for a framework on which future investigations of 'H. contortus' can be based in order to improve prediction of free-living development. The key hypotheses under investigation in the experimental studies concerned the quantitative effects of moisture on free-living development of 'H. contortus', and are summarised in Chapter 1 and in further detail in each of the experimental chapters (Chapter 4-6). Plot experiments were conducted in the Northern Tablelands of NSW, where 'H. contortus' is the most important parasite of sheep. Subsequent laboratory experiments, designed in order to extend and explain the findings of the plot experiments, were conducted in programmable incubators in which temperature was regulated to mimic conditions typical to the Northern Tablelands summer. All experiments focused on testing the effects of a range of rainfall and moisture-related variables on 'H. contortus' development from egg through to infective larvae

Model-Based Interpretation of Time-Varying Medical Data

Temporal concepts are critical is medical therapy-planning. If given early enough, specific therapeutic choices may abort or suppress evolving undesired changes in a patient’s clinical status. Effective medical decision making demands recognition and interpretation of complex temporal changes that permeate the medical record. This paper presents a methodology for representing and using medical knowledge about temporal relationships to infer the presence of clinically relevant events, and describes a program, called TOPAZ, that uses this methodology to generate a narrative summary of such events. A unique feature of TOPAZ is the use of numeric and symbolic modeling techniques to perform temporal reasoning tasks that would be difficult to encode and perform using only one modeling methodology