459 research outputs found

    An economic analysis of options for utilising additional land on a high rainfall Gippsland dairy farm

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    A range of options for utilising additional land on a dairy farm in the high rainfall area of Gippsland were analysed. The aim was to determine if additional land may assist the owners/operators in maintaining or increasing profit in the medium term (5-10 years). Historical trends have been towards fewer, larger, more intensive enterprises, and this project studies the value of additional land in continuing or altering this trend. A case study farm and spreadsheet modelling approach was used to examine these issues. Five different uses for additional land were identified by an expert steering committee, and were compared to the base farm system over a 10-year development period. The results suggest that expanding the milking area by purchasing additional land without a significant increase in herd size (2A) increased annual operating profit by approximately 70,000/yearwithoutincreasingvariabilitywhencomparedtothebasefarmsystem.Thiswastheonlyoptionexaminedtoearnahighenoughinternalrateofreturnonadditionalcapitalinvestmenttojustifytheinvestmentwithoutcapitalgains.Additionalmilkingareawithasubstantialincreaseinstockingrate(2C)significantlyreducedannualoperatingprofit(byapproximately70,000/year without increasing variability when compared to the base farm system. This was the only option examined to earn a high enough internal rate of return on additional capital investment to justify the investment without capital gains. Additional milking area with a substantial increase in stocking rate (2C) significantly reduced annual operating profit (by approximately 70,000/year) and notably increased the variability of these returns. The purchase of an outblock for conserved fodder production improved profitability, but would require some capital gains to be an attractive option on profit measures alone. The most appropriate changes to dairy farm businesses in response to changes in the operating environment will vary from farm to farm. The analysis indicated that simple following previous industry trends may not be appropriate on many farms. Optimising the amount of home grown feed and efficiently using purchased supplements are important, particularly if the milk produced is subject to the fluctuations of an export milk price.Farm Management,

    From bound states to resonances: analytic continuation of the wave function

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    Single-particle resonance parameters and wave functions in spherical and deformed nuclei are determined through analytic continuation in the potential strength. In this method, the analyticity of the eigenvalues and eigenfunctions of the Schroedinger equation with respect to the coupling strength is exploited to analytically continue the bound-state solutions into the positive-energy region by means of Pade' approximants of the second kind. The method is here applied to single-particle wave functions of the 154Sm^{154}Sm and 131Eu^{131}Eu nuclei. A comparison of the results with the direct solution of the Schroedinger equation shows that the method can be confidently applied also in coupled-channel situations requiring high numerical accuracy.Comment: 13 pages, 3 figure

    A simple derivation of level spacing of quasinormal frequencies for a black hole with a deficit solid angle and quintessence-like matter

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    In this paper, we investigate analytically the level space of the imaginary part of quasinormal frequencies for a black hole with a deficit solid angle and quintessence-like matter by the Padmanabhan's method \cite{Padmanabhan}. Padmanabhan presented a method to study analytically the imaginary part of quasinormal frequencies for a class of spherically symmetric spacetimes including Schwarzschild-de Sitter black holes which has an evenly spaced structure. The results show that the level space of scalar and gravitational quasinormal frequencies for this kind of black holes only depend on the surface gravity of black-hole horizon in the range of -1 < w < -1/3, respectively . We also extend the range of ww to w1w \leq -1, the results of which are similar to that in -1 < w < -1/3 case. Particularly, a black hole with a deficit solid angle in accelerating universe will be a Schwarzschild-de Sitter black hole, fixing w=1w = -1 and ϵ2=0\epsilon^2 = 0. And a black hole with a deficit solid angle in the accelerating universe will be a Schwarzschild black hole,when ρ0=0\rho_0 = 0 and ϵ2=0\epsilon^2 = 0. In this paper, ww is the parameter of state equation, ϵ2\epsilon^2 is a parameter relating to a deficit solid angle and ρ0\rho_0 is the density of static spherically symmetrical quintessence-like matter at r=1r = 1.Comment: 6 pages, Accepted for publication in Astrophysics & Space Scienc

    Vertically Self-Gravitating ADAFs in the Presence of Toroidal Magnetic Field

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    Force due to the self-gravity of the disc in the vertical direction is considered to study its possible effects on the structure of a magnetized advection-dominated accretion disc. We present steady-sate self similar solutions for the dynamical structure of such a type of the accretion flows. Our solutions imply reduced thickness of the disc because of the self-gravity. It also imply that the thickness of the disc will increase by adding the magnetic field strength.Comment: Accepted for publication in Astrophysics and Space Science

    Dimensional and Temperature Crossover in Trapped Bose Gases

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    We investigate the long-range phase coherence of homogeneous and trapped Bose gases as a function of the geometry of the trap, the temperature, and the mean-field interactions in the weakly interacting limit. We explicitly take into account the (quasi)condensate depletion due to quantum and thermal fluctuations, i.e., we include the effects of both phase and density fluctuations. In particular, we determine the phase diagram of the gas by calculating the off-diagonal one-particle density matrix and discuss the various crossovers that occur in this phase diagram and the feasibility of their experimental observation in trapped Bose gases.Comment: One figure added, typos corrected, refernces adde

    Updated meta-analysis of randomized controlled trials comparing conventional excisional haemorrhoidectomy with LigaSure for haemorrhoids

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    Background:\ud To compare the surgical outcome of haemorrhoidectomy performed using LigaSure bipolar diathermy with conventional haemorrhoidectomy.\ud \ud Methods:\ud Only randomized and alternate allocated studies were included from the major electronic databases using the search terms "ligasure" and "haemorrhoids" Duration of operation, blood loss during operation, postoperative pain score, wound healing, in-hospital stay, time to return to normal activities and complications were assessed.\ud \ud Results:\ud The 11 trials contained a total of 1,046 patients; the largest study was based on 273 patients and two earlier studies were based on 34 patients. No significant gender mismatch between the groups was reported in any of the studies. The patients’ ages were similar between groups in the studies, as was disease severity. All 11 studies reported a shorter duration of the operation when using LigaSure compared to the conventional technique (p<0.001). The postoperative pain score (p=0.001) and blood loss during operation (p=0.001) were significantly reduced. After LigaSure haemorrhoidectomy wound healing (p=0.004) and the return to normal activities (p=0.001) were significantly faster than after conventional haemorrhoidectomy. However, the overall incidence of complications reported was not significantly different (p=0.056).\ud \ud Conclusions:\ud LigaSure is an effective instrument for haemorrhoidectomy which results in less blood loss, quicker wound healing and earlier return to work.\u

    A 10-GHz quasi-optical grid amplifier using integrated HBT differential pairs

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    Theoretical study of the absorption spectra of the sodium dimer

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    Absorption of radiation from the sodium dimer molecular states correlating to Na(3s)-Na(3s) is investigated theoretically. Vibrational bound and continuum transitions from the singlet X Sigma-g+ state to the first excited singlet A Sigma-u+ and singlet B Pi-u states and from the triplet a Sigma-u+ state to the first excited triplet b Sigma-g+ and triplet c Pi-g states are studied quantum-mechanically. Theoretical and experimental data are used to characterize the molecular properties taking advantage of knowledge recently obtained from ab initio calculations, spectroscopy, and ultra-cold atom collision studies. The quantum-mechanical calculations are carried out for temperatures in the range from 500 to 3000 K and are compared with previous calculations and measurements where available.Comment: 19 pages, 8 figures, revtex, eps

    Demonstration of a novel technique to measure two-photon exchange effects in elastic e±pe^\pm p scattering

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    The discrepancy between proton electromagnetic form factors extracted using unpolarized and polarized scattering data is believed to be a consequence of two-photon exchange (TPE) effects. However, the calculations of TPE corrections have significant model dependence, and there is limited direct experimental evidence for such corrections. We present the results of a new experimental technique for making direct e±pe^\pm p comparisons, which has the potential to make precise measurements over a broad range in Q2Q^2 and scattering angles. We use the Jefferson Lab electron beam and the Hall B photon tagger to generate a clean but untagged photon beam. The photon beam impinges on a converter foil to generate a mixed beam of electrons, positrons, and photons. A chicane is used to separate and recombine the electron and positron beams while the photon beam is stopped by a photon blocker. This provides a combined electron and positron beam, with energies from 0.5 to 3.2 GeV, which impinges on a liquid hydrogen target. The large acceptance CLAS detector is used to identify and reconstruct elastic scattering events, determining both the initial lepton energy and the sign of the scattered lepton. The data were collected in two days with a primary electron beam energy of only 3.3 GeV, limiting the data from this run to smaller values of Q2Q^2 and scattering angle. Nonetheless, this measurement yields a data sample for e±pe^\pm p with statistics comparable to those of the best previous measurements. We have shown that we can cleanly identify elastic scattering events and correct for the difference in acceptance for electron and positron scattering. The final ratio of positron to electron scattering: R=1.027±0.005±0.05R=1.027\pm0.005\pm0.05 for =0.206=0.206 GeV2^2 and 0.830ϵ0.9430.830\leq \epsilon\leq 0.943
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