17,719 research outputs found

    Lump Sum versus Annuity: Choices of Kentucky Farmers during the Tobacco Buyout Program

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    Our study uses the data collected during the implementation of the tobacco buyout program in Kentucky to evaluate how rural households, diverse in income, age, family structure, location, education level, and other characteristics, made a choice between annuities and a lump-sum payment. Subjects in our field experiment did not have to retire or change their employment, as did subjects in many field studies of the choice between annuities and lump-sum payments, which allowed us to evaluate the relationship between the option choice and a decision whether to exit the tobacco market. Our results suggest that while discounted utility theory gives acceptable predictions of the farmers’ behavior, other factors have to be taken into consideration. First, there are consistent biases that describe individual intertemporal behavior, such as availability bias or acquiescence bias. Second, there is a certain degree of heterogeneity in individual intertemporal preferences that correlates with their personal characteristics, such as education and production status. Third, our analysis revealed that the decision to exit the tobacco market positively correlated with the decision to take a lump-sum payment.annuity, family business system, intertemporal choice, lump sum, tobacco buyout, Agribusiness, Consumer/Household Economics, Institutional and Behavioral Economics, Marketing, G11, H31, J10,

    Orbital order and ferrimagnetic properties of the new compound Sr8CaRe3Cu4O24Sr_8 Ca Re_3 Cu_4 O_{24}

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    By means of the LSDA+U method and the Green function method, we investigate the electronic and magnetic properties of the new material of Sr8_8CaRe3_3Cu4_4O24_{24}. Our LSDA+U calculation shows that this system is an insulator with a net magnetic moment of 1.01 μB\mu_{\rm B}/f.u., which is in good agreement with the experiment. Magnetic moments are mainly located at Cu atoms, and the magnetic moments of neighboring Cu sites align anti-parallel. It is the non-magnetic Re atoms that induce an orbital order of dd electrons of Cu atoms, which is responsible for the strong exchange interaction and the high magnetic transition temperature. Based on the LSDA+U results, we introduce an effective model for the spin degrees of freedom, and investigate the finite-temperature properties by the Green function method. The obtained results are consistent with the experimental results, indicating that the spin-alternating Heisenberg model is suitable for this compound.Comment: 8 pages and 5 figur

    Migration of income-support recipients from non-metropolitan NSW and SA into Sydney and Adelaide

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    Nancy Marshall, Ian Burnley, Peter Murphy, Graeme Hug

    Optimisation and effects of coagulant type, pH and ozonation on clarification for automatic coagulation control

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    Four phases of studies were carried out at Burham Water Supply Works in Kent. Firstly jar testing was used to compare and evaluate the performance of five coagulants. The coagulants tested were Polyaluminium Chlorides (PAC) from two suppliers, Aluminium Sulphate (Alum), Polyaluminium Silicate Sulphate (Pass 100) and Alba 18. Jar tests were carried out with coagulant alone and with non-ionic (LT20), weakly cationic (LT22s), and anionic (LT25) polymers. Secondly tests were also carried out at ambient and lower pH’s, at various pre-ozone concentrations. Jar tests indicated PAC with LT20 polymer at a pre-ozone dose of 1.5 mg/1 at pH 7.4 produced the highest water quality. Alum with LT20 was next, giving good and consistent settled water qualities. Pass 100 was circumspect and dependent upon the jar test procedure, but at optimum doses gave water qualities comparable to that of PAC. Alba 18 consistently produced poor settled water qualities. For the third phase, PAC supplied by Industrial Alum Limited (INDA) and Water Treatment Solutions (WTS), Pass 100 and Alum were selected and tested on the clarifier. Alum and PAC (WTS) were tested at pH 7.5, pH 7.3 and ambient pH at pre-ozone concentrations 0.5, 1.0, 1.5 and 2.0 mg/1 with various coagulant and polymer combinations. Pass 100 and PAC (INDA) were tested as describes but at a pre-ozone concentration of 1.5 mg/1. At optimum doses PAC (INDA) was found to perform best at a pre-ozone concentration of 1.5 mg/1 at pH 7.5. PAC (WTS) was next, with similar results. Alum produced good and consistent water qualities. Pass 100 was affected by polymer addition and was out-performed by PAC and Alum coagulants. The parameters taken into account were settled turbidity, residual aluminium, and removal of TOC, chlorophyll, phaeophytin, iron, manganese, and colour. If PAC with acid dosing can be shown to work full scale annually it would be economic to do so and to dose acid to achieve a pH of 7.5 when required. Phase four involved the evaluation of an automatic coagulant control system that would automatically optimise the coagulant, acid and polyelectrolyte doses added to the water. This was evaluated using jar tests with PAC and Alum coagulants. The AC250 system indicated the potential to improve the quality of treated water whilst minimising the coagulant dose. In this case PAC would provide further coagulant savings, with consequent sludge savings.MRe

    Discussion of “Observation of ground movement with existing pile groups due to tunneling in sand using centrifuge modelling” by Ittichai Boonsiri and Jiro Takemura

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    This discussion aims to highlight the underlying cause of several aspects of the greenfield settlement data presented by Boonsiri and Takemura (Geotech Geol Eng 33(3):621–640, 2015). The discussion considers, for the geotechnical centrifuge tests that were reported, the effects of the boundary conditions imposed at the model tunnel on resulting settlements. Data obtained using the rigid boundary model tunnel in Boonsiri and Takemura (Geotech Geol Eng 33(3):621–640, 2015) are compared against other available data from tests using a fluid-filled flexible membrane model tunnel. It is demonstrated that the boundary conditions used to simulate tunnel ground loss have an important impact on the settlement mechanism; compared to a fluid-filled flexible membrane, a rigid boundary model tunnel results in wider settlement troughs, which do not vary in shape considerably with changes in relative tunnel depth, and can result in higher ratios between the area of the settlement troughs and the tunnel ground loss. The appropriateness of the different tunnel boundary conditions is also discussed

    Photoemission Evidence for a Remnant Fermi Surface and d-Wave-Like Dispersion in Insulating Ca2CuO2Cl2

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    An angle resolved photoemission study on Ca2CuO2Cl2, a parent compound of high Tc superconductors is reported. Analysis of the electron occupation probability, n(k) from the spectra shows a steep drop in spectral intensity across a contour that is close to the Fermi surface predicted by the band calculation. This analysis reveals a Fermi surface remnant even though Ca2CuO2Cl2 is a Mott insulator. The lowest energy peak exhibits a dispersion with approximately the |cos(kxa)-cos(kya)| form along this remnant Fermi surface. Together with the data from Dy doped Bi2Sr2CaCu2O(8 + delta) these results suggest that this d-wave like dispersion of the insulator is the underlying reason for the pseudo gap in the underdoped regime.Comment: 9 pages, including 7 figures. Published in Science, one figure correcte

    Evidence for ACTN3 as a genetic modifier of Duchenne muscular dystrophy

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    Duchenne muscular dystrophy (DMD) is characterized by muscle degeneration and progressive weakness. There is considerable inter-patient variability in disease onset and progression, which can confound the results of clinical trials. Here we show that a common null polymorphism (R577X) in ACTN3 results in significantly reduced muscle strength and a longer 10\u2009m walk test time in young, ambulant patients with DMD; both of which are primary outcome measures in clinical trials. We have developed a double knockout mouse model, which also shows reduced muscle strength, but is protected from stretch-induced eccentric damage with age. This suggests that \u3b1-actinin-3 deficiency reduces muscle performance at baseline, but ameliorates the progression of dystrophic pathology. Mechanistically, we show that \u3b1-actinin-3 deficiency triggers an increase in oxidative muscle metabolism through activation of calcineurin, which likely confers the protective effect. Our studies suggest that ACTN3 R577X genotype is a modifier of clinical phenotype in DMD patients

    Spitzer/IRS Imaging and Spectroscopy of the luminous infrared galaxy NGC 6052 (Mrk 297)

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    We present photometric and spectroscopic data of the interacting starburst galaxy NGC 6052 obtained with the Spitzer Space Telescope. The mid-infrared (MIR) spectra of the three brightest spatially resolved regions in the galaxy are remarkably similar and are consistent with dust emission from young nearly coeval stellar populations. Analysis of the brightest infrared region of the system, which contributes ~18.5 % of the total 16\micron flux, indicates that unlike similar off-nuclear infrared-bright regions found in Arp 299 or NGC 4038/9, its MIR spectrum is inconsistent with an enshrouded hot dust (T > 300K) component. Instead, the three brightest MIR regions all display dust continua of temperatures less than ~ 200K. These low dust temperatures indicate the dust is likely in the form of a patchy screen of relatively cold material situated along the line of sight. We also find that emission from polycyclic aromatic hydrocarbons (PAHs) and the forbidden atomic lines is very similar for each region. We conclude that the ionization regions are self-similar and come from young (about 6 Myr) stellar populations. A fourth region, for which we have no MIR spectra, exhibits MIR emission similar to tidal tail features in other interacting galaxies.Comment: 20 pages in preprint form, estimated 7 pages in ApJ Aeptember 10, 2007, v666n 2 issue, six encapsulated postscript figure

    The importance of transport model uncertainties for the estimation of CO2 sources and sinks using satellite measurements

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    This study presents a synthetic model intercomparison to investigate the importance of transport model errors for estimating the sources and sinks of CO2 using satellite measurements. The experiments were designed for testing the potential performance of the proposed CO2 lidar A-SCOPE, but also apply to other space borne missions that monitor total column CO2. The participating transport models IFS, LMDZ, TM3, and TM5 were run in forward and inverse mode using common a priori CO2 fluxes and initial concentrations. Forward simulations of column averaged CO2 (xCO2) mixing ratios vary between the models by s=0.5 ppm over the continents and s=0.27 ppm over the oceans. Despite the fact that the models agree on average on the sub-ppm level, these modest differences nevertheless lead to significant discrepancies in the inverted fluxes of 0.1 PgC/yr per 106 km2 over land and 0.03 PgC/yr per 106 km2 over the ocean. These transport model induced flux uncertainties exceed the target requirement that was formulated for the A-SCOPE mission of 0.02 PgC/yr per 106 km2, and could also limit the overall performance of other CO2 missions such as GOSAT. A variable, but overall encouraging agreement is found in comparison with FTS measurements at Park Falls, Darwin, Spitsbergen, and Bremen, although systematic differences are found exceeding the 0.5 ppm level. Because of this, our estimate of the impact of transport model uncerainty is likely to be conservative. It is concluded that to make use of the remote sensing technique for quantifying the sources and sinks of CO2 not only requires highly accurate satellite instruments, but also puts stringent requirements on the performance of atmospheric transport models. Improving the accuracy of these models should receive high priority, which calls for a closer collaboration between experts in atmospheric dynamics and tracer transpor

    J1J2J_1-J_2 Quantum Heisenberg Antiferromagnet: Improved Spin-Wave Theories Versus Exact-Diagonalization Data

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    We reconsider the results cocerning the extreme-quantum S=1/2S=1/2 square-lattice Heisenberg antiferromagnet with frustrating diagonal couplings (J1J2J_1-J_2 model) drawn from a comparison with exact-diagonalization data. A combined approach using also some intrinsic features of the self-consistent spin-wave theory leads to the conclusion that the theory strongly overestimates the stabilizing role of quantum flutcuations in respect to the N\'{e}el phase in the extreme-quantum case S=1/2S=1/2. On the other hand, the analysis implies that the N\'{e}el phase remains stable at least up to the limit J2/J1=0.49J_{2}/J_{1} = 0.49 which is pretty larger than some previous estimates. In addition, it is argued that the spin-wave ansatz predicts the existence of a finite range (J2/J1<0.323J_{2}/J_{1}<0.323 in the linear spin-wave theory) where the Marshall-Peierls sigh rule survives the frustrations.Comment: 13 pages, LaTex, 7 figures on reques
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