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Relationships between sow nutrition, milk yield, milk composition and piglet performance during lactation have been studied in numerous experiments. However, the subsequent effects of these pre-weaning factors on post-weaning piglet performance are less well studied. Commonly a growth check in piglets in response to weaning is noted, but to date it is unknown why some piglets do better than others in this period. The present experiment explored some of the pre-weaning factors that could explain the variability in piglet post-weaning growth.
The performance of piglets from 41 litters was monitored during a lactation period of 26 days. Litter size was standardised to 10 piglets, which were not offered creep food. Piglets were weighed individually on a weekly basis from farrowing to weaning at 26 days. Daily litter milk intake was estimated by a weigh-suckle-weigh technique in 24 litters on 4 occasions at 5 day intervals across lactation. On the day after each of these days, the composition of milk was determined from milk samples obtained by hand milking following oxytocin injection. Litter milk intake and composition of milk were used to calculate the mean daily piglet nutrient intakes during lactation. After weaning some piglets were sacrificed for the analysis of body composition and 310 piglets out of the 41 litters were penned in litter groups in controlled environment flat decks for two weeks to monitor daily group feed intakes and weekly individual growth rates.
Starch and fat are the two major energy sources available for sow lactation diets. Fat is more energy dense and can be used to maximise energy intakes, particularly in sows with low appetite. However, the quantity of milk produced in sows has been associated with milk lactose production and the main precursor for lactose is glucose, for which dietary starch is the major source. It is therefore important to know the consequences of using a glucose deficient energy source, such as fat, compared to starch in lactation diets. The following experiment was designed to assess energy sources in lactation diets at an isocaloric level in determining sow and piglet performance, in association with the effects of dietary glucose availability on the metabolic state of the sow around peak lactation.
The Taipan galaxy survey (hereafter simply ‘Taipan’) is a multi-object spectroscopic survey starting in 2017 that will cover 2π steradians over the southern sky (δ ≲ 10°, |b| ≳ 10°), and obtain optical spectra for about two million galaxies out to z < 0.4. Taipan will use the newly refurbished 1.2-m UK Schmidt Telescope at Siding Spring Observatory with the new TAIPAN instrument, which includes an innovative ‘Starbugs’ positioning system capable of rapidly and simultaneously deploying up to 150 spectroscopic fibres (and up to 300 with a proposed upgrade) over the 6° diameter focal plane, and a purpose-built spectrograph operating in the range from 370 to 870 nm with resolving power R ≳ 2000. The main scientific goals of Taipan are (i) to measure the distance scale of the Universe (primarily governed by the local expansion rate, H0) to 1% precision, and the growth rate of structure to 5%; (ii) to make the most extensive map yet constructed of the total mass distribution and motions in the local Universe, using peculiar velocities based on improved Fundamental Plane distances, which will enable sensitive tests of gravitational physics; and (iii) to deliver a legacy sample of low-redshift galaxies as a unique laboratory for studying galaxy evolution as a function of dark matter halo and stellar mass and environment. The final survey, which will be completed within 5 yrs, will consist of a complete magnitude-limited sample (i ⩽ 17) of about 1.2 × 106 galaxies supplemented by an extension to higher redshifts and fainter magnitudes (i ⩽ 18.1) of a luminous red galaxy sample of about 0.8 × 106 galaxies. Observations and data processing will be carried out remotely and in a fully automated way, using a purpose-built automated ‘virtual observer’ software and an automated data reduction pipeline. The Taipan survey is deliberately designed to maximise its legacy value by complementing and enhancing current and planned surveys of the southern sky at wavelengths from the optical to the radio; it will become the primary redshift and optical spectroscopic reference catalogue for the local extragalactic Universe in the southern sky for the coming decade.
The Southern Hemisphere VLBI Experiment (SHEVE) program is aimed at producing high-resolution images of southern radio sources. The radio telescopes of the present SHEVE array are described below and some recent results presented.
Two important factors for understanding the physical nature of compact steep spectrum (CSS) radio sources are determining the correct radio morphological classification of these objects together with their characteristics in wavebands different from the radio (Fanti et al. 1995, A&A, 302, 317). Seven CSS sources (linear dimensions < 30kpc for Ho = 50 kms–1Mpc–1 and α > 0.5, S ≃ v–α) have been found in a complete sample of strong southern radio sources. This group of CSS sources is particularly interesting because some optical and X-ray information is already available as part of a more general study of southern radio sources (Morganti et al. & Siebert et al. these Proceedings). The spectra of all the sources were presented in Tadhunter et al. (1993, MNRAS, 263, 999.) Here we present VLBI observations for three of these sources (0252-71, 1306-09 and 1814-63). The remaining four have already been imaged with VLBI (King et al. these Proceedings).
PKS 1934–638 is an archetypal GPS source, peaking at 1.4 GHz and exhibits almost no flux density variability. VLBI images at frequencies of .843, 2.3, 4.8, & 8.4 were made with the southern hemisphere VLBI array and they reveal that the source is a 42 mas compact double. There is no detectable change in separation over the last 20 years, yielding an upper limit of ~ 0.03c ± 0.2c on any expansion velocity. The spectral shapes of the two components are remarkably similar, despite indications of finer structure on longer baselines. Magnetic field calculations indicate fields of a few mGauss and the results are consistent with equipartition.
Intracranial volume (ICV) has been proposed as a measure of maximum lifetime brain size. Accurate ICV measures require neuroimaging which is not always feasible for epidemiologic investigations. We examined head circumference as a useful surrogate for ICV in older adults.
99 older adults underwent Magnetic Resonance Imaging (MRI). ICV was measured by Statistical Parametric Mapping 8 (SPM8) software or Functional MRI of the Brain Software Library (FSL) extraction with manual editing, typically considered the gold standard. Head circumferences were determined using standardized tape measurement. We examined estimated correlation coefficients between head circumference and the two MRI-based ICV measurements.
Head circumference and ICV by SPM8 were moderately correlated (overall r = 0.73, men r = 0.67, women r = 0.63). Head circumference and ICV by FSL were also moderately correlated (overall r = 0.69, men r = 0.63, women r = 0.49).
Head circumference measurement was strongly correlated with MRI-derived ICV. Our study presents a simple method to approximate ICV among older patients, which may prove useful as a surrogate for cognitive reserve in large scale epidemiologic studies of cognitive outcomes. This study also suggests the stability of head circumference correlation with ICV throughout the lifespan.
Asymptomatic carriage of gastrointestinal zoonoses is more common in people whose profession involves them working directly with domesticated animals. Subclinical infections (defined as an infection in which symptoms are either asymptomatic or sufficiently mild to escape diagnosis) are important within a community as unknowing (asymptomatic) carriers of pathogens do not change their behaviour to prevent the spread of disease; therefore the public health significance of asymptomatic human excretion of zoonoses should not be underestimated. However, optimal strategies for managing diseases where asymptomatic carriage instigates further infection remain unresolved, and the impact on disease management is unclear. In this review we consider the environmental pathways associated with prolonged antigenic exposure and critically assess the significance of asymptomatic carriage in disease outbreaks Although screening high-risk groups for occupationally acquired diseases would be logistically problematical, there may be an economic case for identifying and treating asymptomatic carriage if the costs of screening and treatment are less than the costs of identifying and treating those individuals infected by asymptomatic hosts.
The illegal trade in wild harvested plants and animals is a significant threat to populations and species worldwide. There is concern that in many countries sanctions for wildlife trade crimes are insufficient to act as a deterrent, and do not reflect the seriousness of offences. For these reasons it is important to understand professional and public opinions as to which aspects of such crimes make them more or less serious, and so deserving of a greater or lesser sentence. Conjoint analysis, a method used in marketing to understand which characteristics of a product are valued by consumers, was used to investigate which attributes of hypothetical wildlife trade offences (threat status and taxon of species involved, illegal profit, previous convictions and plea) UK-based conservation professionals, magistrates and the general public considered most important when sentencing wildlife criminals in the UK. Eighty-seven per cent of 682 respondents completed enough of the survey to be included in the analysis. Magistrates and the public considered illegal profit to be the single most important attribute, while conservationists considered the threat status of the species involved to be most important (considered second most important by magistrates and the public). Magistrates, when presented with adequate information, considered the threat status and corresponding legal protection afforded to wildlife when considering how serious a wildlife trade crime was, and doing so is in line with public opinion on sentencing such offences. This study highlights the importance of ensuring that judiciaries are presented with information concerning both the potential profit and conservation impact of wildlife trade crimes. Sentencing councils must develop appropriate guidelines to support judiciaries in their sentencing of wildlife crimes.
Few hard data are available on emergent diseases. However, the need to mitigate and manage emergent diseases has prompted the use of various expert consultation and opinion elicitation methods. We adapted best-worst scaling (BWS) to elicit experts' assessment of the relative practicality and effectiveness of measures to reduce human exposure to E. coli O157. Cattle vaccination was considered the most effective and hand-washing was considered the most practical measure. BWS proved a powerful tool for expert elicitation as it breaks down a cognitively burdensome process into simple, repeated, tasks. In addition, statistical analysis of the resulting data provides a scaled set of scores for the measures, rather than just a ranking. The use of two criteria (practicality and effectiveness) within the BWS process allows the identification of subsets of measures judged as potentially performing well on both criteria, and conversely those judged to be neither effective nor practical.
We report high frequency electron paramagnetic resonance (EPR) investigations of a series of high spin (total spin up to S = 10) manganese and nickel complexes which have been shown to exhibit single molecule magnetism, including low temperature (below ∼ 1K) hysteresis loops and resonant magnetic quantum tunneling. A cavity perturbation technique enables high sensitivity oriented single crystal EPR measurements spanning a very wide frequency range (16 to 200+ GHz). Fitting of the frequency and field orientation dependence of EPR spectra allows direct determination of the effective spin Hamiltonian parameters. Studies on a range of materials with varying (approximately axial) site symmetries facilitates an assessment of the role of transverse anisotropy (terms in the Hamiltonian that do not commute with ŝz) in the magnetic quantum tunneling phenomenon.
It is well known that much of the sensory input to the central nervous system can be modulated by centrifugally organized control systems that originate in the central nervous system (Head and Holmes, 1911; Hagbarth, 1960). The control mechanisms can be excitatory or inhibitory processes that may occur in the periphery or within the central nervous system. Inhibition can be at pre- and/or postsynaptic sites (Fig. 6.1(I)). Presynaptic inhibition at the first central synapse of a sensory pathway has the potential advantage of being able to reduce sensory input prior to wide dissemination of that sensory input within the central nervous system through the activation of interneuronal networks and multiple ascending pathways, for example, in the spinal cord (Schmidt, 1973; see Chapter 3).
Pre- and postsynaptic inhibition can have somewhat different effects on the stimulus-response curves of second-order sensory neurons, as shown in Fig. 6.1(II). Postsynaptic inhibition involves inhibitory postsynaptic potentials that sum with excitatory postsynaptic potentials (Fig. 6.1(IIA)). If there is a linear summation, the stimulus-response curve will be shifted to the right in a parallel fashion (Carstens et al., 1980). However, if the IPSP is generated in a membrane area near that in which the EPSP is generated, the excitatory current may be shunted and the slope of the stimulus-response curve reduced, causing a reduction in the gain of synaptic transmission (Fig. 6.1(IIB)). A similar reduction in gain can be produced by presynaptic inhibition.
It is well understood that there are different components to the sensation of pain (Melzack and Casey,1968). The sensory-discriminative aspect of pain refers to the location, intensity and quality of the sensory experience of pain. The affective-motivational aspect of pain refers to the unpleasantness of the pain and how likely it is that it will motivate the animal to escape the pain. We refer to these different components of the pain sensation throughout this review as we examine the possibility that these different components are mediated by different structures in the brain.
The spinothalamic tract (STT) is the spinal tract projecting toward the brain which is most often associated with the sensation of pain (Price and Dubner, 1977; Willis, 1985; Price et al., 2003). Cells of origin of the STT can be divided into those which respond to low-threshold stimuli (LT cells), those which respond to stimuli across the intensive continuum into the noxious range (wide dynamic range, WDR), and those that respond only to noxious stimuli (nociceptive specific, NS). Evidence that any structure mediates the sensory aspect of pain is grouped into four lines: that the structure is connected to other structures known to demonstrate pain-related activity; that neural elements in that structure respond to noxious stimuli; that stimulation of that structure produces pain; and that interventions which interfere with the function of that structure interfere with the sensation of pain evoked by noxious stimuli (Price and Dubner, 1977).