3,827 research outputs found
The use of feed blocks as supplementation for theupland hill flock: (1) Improving organic ewe productivity and performance
This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR). Maintaining ewe performance in winter poses particular problems for organic farming in the uplands where the availability of both grazing and home produced forage may be restricted. This trial evaluated approved non-organic feed blocks as dietary supplement for ewes grazing pastures between 300 and 550 m
Eight years of organic farming at Pwllpeiran – livestock production and the financial performance of organic upland
This report was presented at the UK Organic Research 2002 Conference. Established for 8 years, this project evaluates the practicalities of organic beef and sheep production on an upland farm in an ESA. Grassland productivity, stocking rates and animal performance are closely related to seasonal variations in the clover content of the small area of improved land. Improving sales have been offset by increasing input costs. Subsidy payments assist financial performance, but ESA prescriptions effectively prevent increased production
The use of feed blocks as supplementation for the upland hill flock: (2) Cost effective lamb production
This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR).Under EU organic livestock regulations introduced in 2000, new restrictions were placed on the use of bought-in feedstuffs in hill systems. These reduced the non-organic annual percentage previously allowed in LFAs from 20% to 10% of annual dry matter intake. A further stepping down of these allowances may be introduced ahead of a complete ban in 2005. Bought-in feed supplements must therefore, be used strategically and offer “best value for money” in terms of ewe performance and lamb growth. The economic cost of supplementing the diet of twin-rearing ewes post lambing with either an approved non-organic feed block + half ration of commercial concentrate mix (B+CCM) or full ration commercial concentrate mix (CCM) was investigated. Lambs reared by ewes receiving the B+CCM diet had a greater liveweight gain than those reared by ewes receiving the CCM diet per kg of ewe supplementary feed. The costs in terms of kg lamb liveweight were lower for the B+CCM ewes than the CCM ewe
Isotropic Oscillator Under a Magnetic and Spatially Varying Electric Field
We investigate the energy levels of a particle confined in the isotropic oscillator potential with a magnetic and spatially varying electric field. Here we are able to exactly solve the Schrodinger equation, using matrix methods, for the first excited states. To this end we find that the spatial gradient of the electric field acts as a magnetic field in certain circumstances. Here we present the changes in the energy levels as functions of the electric field, and other parameters
The MgSiO_3 system at high pressure: Thermodynamic properties of perovskite, postperovskite, and melt from global inversion of shock and static compression data
We present new equation-of-state (EoS) data acquired by shock loading to pressures up to 245 GPa on both low-density samples (MgSiO_3 glass) and high-density, polycrystalline aggregates (MgSiO_3 perovskite + majorite). The latter samples were synthesized using a large-volume press. Modeling indicates that these materials transform to perovskite, postperovskite, and/or melt with increasing pressure on their Hugoniots. We fit our results together with existing P-V-T data from dynamic and static compression experiments to constrain the thermal EoS for the three phases, all of which are of fundamental importance to the dynamics of the lower mantle. The EoS for perovskite and postperovskite are well described with third-order Birch-Murnaghan isentropes, offset with a Mie-Grüneisen-Debye formulation for thermal pressure. The addition of shock data helps to distinguish among discrepant static studies of perovskite, and for postperovskite, constrain a value of K' significantly larger than 4. For the melt, we define for the first time a single EoS that fits experimental data from ambient pressure to 230 GPa; the best fit requires a fourth-order isentrope. We also provide a new EoS for Mg_2SiO_4 liquid, calculated in a similar manner. The Grüneisen parameters of the solid phases decrease with pressure, whereas those of the melts increase, consistent with previous shock wave experiments as well as molecular dynamics simulations. We discuss implications of our modeling for thermal expansion in the lower mantle, stabilization of ultra-low-velocity zones associated with melting at the core-mantle boundary, and crystallization of a terrestrial magma ocean
The Effect of Particle Strength on the Ballistic Resistance of Shear Thickening Fluids
The response of shear thickening fluids (STFs) under ballistic impact has
received considerable attention due to its field-responsive nature. While
efforts have primarily focused on the response of traditional ballistic fabrics
impregnated with fluids, the response of pure STFs to penetration has received
limited attention. In the present study, the ballistic response of pure STFs is
investigated and the effect of fluid density and particle strength on ballistic
performance is isolated. The loss of ballistic resistance of STFs at higher
impact velocities is governed by particle strength, indicating the range of
velocities over which they may provide effective armor solutions.Comment: 4 pages, 4 figure
The Qualitative Interview in Psychology and the Study of Social Change: Sexual Identity Development, Minority Stress, and Health in the Generations Study.
Interviewing is considered a key form of qualitative inquiry in psychology that yields rich data on lived experience and meaning making of life events. Interviews that contain multiple components informed by specific epistemologies have the potential to provide particularly nuanced perspectives on psychological experience. We offer a methodological model for a multi-component interview that draws upon both pragmatic and constructivist epistemologies to examine generational differences in the experience of identity development, stress, and health among contemporary sexual minorities in the United States. Grounded in theories of life course, narrative, and intersectionality, we designed and implemented a multi-component protocol that was administered among a diverse sample of three generations of sexual minority individuals. For each component, we describe the purpose and utility, underlying epistemology, foundational psychological approach, and procedure, and we provide illustrative data from interviewees. We discuss procedures undertaken to ensure methodological integrity in process of data collection, illustrating the implementation of recent guidelines for qualitative inquiry in psychology. We highlight the utility of this qualitative multi-component interview to examine the way in which sexual minorities of distinct generations have made meaning of significant social change over the past half-century
Othello and the Democrats
Bad criticism is often the result of imposing on a work an unhelpful theoretical model: in the case of Othello, a tragic model developed by nineteenth-century critics out of Aristotle's Poetics. We are accustomed to look for a tragic hero with a fatal flaw, with hubris or with hamartia (in the non-Aristotelian sense of moral fault) that leads to catastrophe. Criticism of Shakespeare's Othello is still very much engaged in a long war over the personality and progress of the tragic hero. There are two conflicting schools, each of which offers an interpretation that is faithful to details but unsatisfactory as a final account; and if individuals have withdrawn from the contest, it was more because discussion had grown tedious than because it had reached solutions. A. C. Bradley might be taken as one extreme, giving us the noble Moor, virtuous, open and majestic, a "rough diamond" whose only conceivable flaw might be that his generous nature prompted him to over-impulsive action. The problem with such a reading of the character, as Harley Granville-Barker found, is that Othello's end must seem meaningless and non-uplifting. At the other extreme, we have T. S. Eliot and, after him, F. R. Leavis offering us an unheroic Moor, a self-dramatizer and unconscious poseur, a life denying romantic who retreats at the last into protective self deception and avoidance of reality
Fragmentation of a molten metal droplet in an ambient water flow
The influence of an ambient fluid flow on the fragmentation of hot molten tin droplets (initially at 800°C) and cold low melting point alloy droplets (initially at 70°C) in water is investigated with high-speed photography and flash radiography. The water is accelerated using a converging nozzle to a constant speed of up to 30 m/s using a double piston arrangement designed to eliminate the formation of a shock wave that is present in most earlier studies. At low flow velocities, the fragmentation of hot droplets is governed by thermal effects and vapour formation, growth, and collapse. At high flow velocities, vapour formation is suppressed and the droplet fragmentation is determined by hydrodynamic effects in which hydrodynamic instabilities (Rayleigh-Taylor and Kelvin-Helmholtz) and wavecrest stripping all play a role in the droplet breakup. At intermediate flow velocities, both thermal and hydrodynamic effects play a role. Quantitative image analysis of the radiographs is used to determine the spatial distribution of the droplet mass during the fragmentation process. Comparison with earlier work in which the ambient flow is preceded by a strong shock wave indicates that the transition from thermal to hydrodynamic breakup is strongly dependent on the pressure field
Scan time reduction for readout-segmented EPI using simultaneous multislice acceleration: Diffusion-weighted imaging at 3 and 7 Tesla
Purpose:
Readout‐segmented echo‐planar imaging (rs‐EPI) can provide high quality diffusion data because it is less prone to distortion and blurring artifacts than single‐shot echo‐planar imaging (ss‐EPI), particularly at higher resolution and higher field. Readout segmentation allows shorter echo‐spacing and echo train duration, resulting in reduced image distortion and blurring, respectively, in the phase‐encoding direction. However, these benefits come at the expense of longer scan times because the segments are acquired in multiple repetitions times (TRs). This study shortened rs‐EPI scan times by reducing the TR duration with simultaneous multislice acceleration.
Methods:
The blipped‐CAIPI method for slice acceleration with reduced g‐factor SNR loss was incorporated into the diffusion‐weighted rs‐EPI sequence. The rs‐ and ss‐EPI sequences were compared at a range of resolutions at both 3 and 7 Tesla in terms of image fidelity and diffusion postprocessing results.
Results:
Slice‐accelerated clinically useful trace‐weighted images and tractography results are presented. Tractography analysis showed that the reduced artifacts in rs‐EPI allowed better discrimination of tracts than ss‐EPI.
Conclusion:
Slice acceleration reduces rs‐EPI scan times providing a practical alternative to diffusion‐weighted ss‐EPI with reduced distortion and high resolution. Magn Reson Med 74:136–149, 2015
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