2,937 research outputs found

    Can’t See the Wood for the Trees: The Returns to Farm Forestry in Ireland

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    working paperThe period 2007-2009 witnessed considerable variability in the price of outputs such as milk and cereals and this was compounded by a high degree of volatility in the price of inputs such as fertilizer, animal feed and energy. Previously, Irish farms have used the returns to off-farm employment as well as agricultural support payments such as the Single Farm Payment (SFP) and the Rural Environmental Protection Scheme (REPS) to protect their living standards against low and uncertain agricultural market returns. However, the downturn in the Irish economy has led to a reduction in the availability of off-farm employment and also the discontinuation of REPS. This may lead to an increase in afforestation on Irish farms, as forestry offers greater certainty through the provision of an annual premium in addition to the SFP. However, the decision to afforest represents a significant long-term investment decision that should not be entered into without careful economic consideration. The aim of this paper is to use the Discounted Cash Flow (DCF) analysis method to calculate the returns to forestry under alternative opportunity costs associated with conventional agricultural activities being superseded. The returns to forestry are calculated using the Forestry Investment Value Estimator (FIVE). These returns were then incorporated in the DCF model along with the returns to five conventional agricultural enterprises, which would potentially be superseded by forestry. This approach allows for the calculation of the Net Present Value (NPV) of three forestry scenarios

    Critical properties of the unconventional spin-Peierls system TiOBr

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    We have performed detailed x-ray scattering measurements on single crystals of the spin-Peierls compound TiOBr in order to study the critical properties of the transition between the incommensurate spin-Peierls state and the paramagnetic state at Tc2 ~ 48 K. We have determined a value of the critical exponent beta which is consistent with the conventional 3D universality classes, in contrast with earlier results reported for TiOBr and TiOCl. Using a simple power law fit function we demonstrate that the asymptotic critical regime in TiOBr is quite narrow, and obtain a value of beta_{asy} = 0.32 +/- 0.03 in the asymptotic limit. A power law fit function which includes the first order correction-to-scaling confluent singularity term can be used to account for data outside the asymptotic regime, yielding a more robust value of beta_{avg} = 0.39 +/- 0.05. We observe no evidence of commensurate fluctuations above Tc1 in TiOBr, unlike its isostructural sister compound TiOCl. In addition, we find that the incommensurate structure between Tc1 and Tc2 is shifted in Q-space relative to the commensurate structure below Tc1.Comment: 12 pages, 8 figures. Submitted to Physical Review

    Commensurate Fluctuations in the Pseudogap and Incommensurate spin-Peierls Phases of TiOCl

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    X-ray scattering measurements on single crystals of TiOCl reveal the presence of commensurate dimerization peaks within both the incommensurate spin-Peierls phase and the so-called pseudogap phase above T_c2. This scattering is relatively narrow in Q-space indicating long correlation lengths exceeding ~ 100 A below T* ~ 130 K. It is also slightly shifted in Q relative to that of the commensurate long range ordered state at the lowest temperatures, and it coexists with the incommensurate Bragg peaks below T_c2. The integrated scattering over both commensurate and incommensurate positions evolves continuously with decreasing temperature for all temperatures below T* ~ 130 K.Comment: To appear in Physical Review B: Rapid Communications. 5 page

    Suppression of the commensurate spin-Peierls state in Sc-doped TiOCl

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    We have performed x-ray scattering measurements on single crystals of the doped spin-Peierls compound Ti(1-x)Sc(x)OCl (x = 0, 0.01, 0.03). These measurements reveal that the presence of non-magnetic dopants has a profound effect on the unconventional spin-Peierls behavior of this system, even at concentrations as low as 1%. Sc-doping suppresses commensurate fluctuations in the pseudogap and incommensurate spin-Peierls phases of TiOCl, and prevents the formation of a long-range ordered spin-Peierls state. Broad incommensurate scattering develops in the doped compounds near Tc2 ~ 93 K, and persists down to base temperature (~ 7 K) with no evidence of a lock-in transition. The width of the incommensurate dimerization peaks indicates short correlation lengths on the order of ~ 12 angstroms below Tc2. The intensity of the incommensurate scattering is significantly reduced at higher Sc concentrations, indicating that the size of the associated lattice displacement decreases rapidly as a function of doping.Comment: 7 pages, 5 figure

    Every Sentiment Has a History : Affect and the Archive: An Interview with Ann Stoler

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    Ann Stoler is Willy Brandt Distinguished University Professor of Anthropology and Historical Studies at The New School for Social Research. She is the director of the Institute for Critical Social Inquiry. She has worked extensively on the politics of knowledge, colonial governance, racial epistemologies, the sexual politics of empire, and ethnography of the archives. Her books include Race and the Education of Desire: Foucault\u27s History of Sexuality and the Colonial Order of Things (1995), Carnal Knowledge and Imperial Power: Race and the Intimate in Colonial Rule (2002, 2010), and Along the Archival Grain: Epistemic Anxieties and Colonial Common Sense (2009)

    Vertical Distribution of Aersols and Water Vapor Using CRISM Limb Observations

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    Near-infrared spectra taken in a limb-viewing geometry by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on-board the Mars Reconnaissance Orbiter (MRO) provide a useful tool for probing atmospheric structure. Specifically, the observed radiance as a function of wavelength and height above the limb allows the vertical distribution of both dust and ice aerosols to be retrieved. These data serve as an important supplement to the aerosol profiling provided by the MRO/MCS instrument allowing independent validation and giving additional information on particle physical and scattering properties through multi-wavelength studies. A total of at least ten CRISM limb observations have been taken so far covering a full Martian year. Each set of limb observations nominally contains about four dozen scans across the limb giving pole-to-pole coverage for two orbits at roughly 100 and 290 W longitude over the Tharsis and Syrtis/Hellas regions, respectively. At each longitude, limb scans are spaced roughly 10 degrees apart in latitude, with a vertical spatial resolution on the limb of roughly 800 m. Radiative transfer modeling is used to model the observations. We compute synthetic CRISM limb spectra using a discrete-ordinates radiative transfer code that accounts for multiple scattering from aerosols and accounts for spherical geometry of the limb observations by integrating the source functions along curved paths in that coordinate system. Retrieved are 14-point vertical profiles for dust and water ice aerosols with resolution of 0.4 scale heights between one and six scale heights above the surface. After the aerosol retrieval is completed, the abundances of C02 (or surface pressure) and H20 gas are retrieved by matching the depth of absorption bands at 2000 nm for carbon dioxide and at 2600 run for water vapor. In addition to the column abundance of water vapor, limited information on its vertical structure can also be retrieved depending on the signal available from aerosol scattering

    Parameterization for in-silico modeling of ion channel interactions with drugs

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    Since the first Hodgkin and Huxley ion channel model was described in the 1950s, there has been an explosion in mathematical models to describe ion channel function. As experimental data has become richer, models have concomitantly been improved to better represent ion channel kinetic processes, although these improvements have generally resulted in more model complexity and an increase in the number of parameters necessary to populate the models. Models have also been developed to explicitly model drug interactions with ion channels. Recent models of drug-channel interactions account for the discrete kinetics of drug interaction with distinct ion channel state conformations, as it has become clear that such interactions underlie complex emergent kinetics such as use-dependent block. Here, we describe an approach for developing a model for ion channel drug interactions. The method describes the process of extracting rate constants from experimental electrophysiological function data to use as initial conditions for the model parameters. We then describe implementation of a parameter optimization method to refine the model rate constants describing ion channel drug kinetics. The algorithm takes advantage of readily available parallel computing tools to speed up the optimization. Finally, we describe some potential applications of the platform including the potential for gaining fundamental mechanistic insights into ion channel function and applications to in silico drug screening and development

    Spin Waves in the Ferromagnetic Ground State of the Kagome Staircase System Co3V2O8

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    Inelastic neutron scattering measurements were performed on single crystal Co3V2O8 wherein magnetic cobalt ions reside on distinct spine and cross-tie sites within kagome staircase planes. This system displays a rich magnetic phase diagram which culminates in a ferromagnetic ground state below Tc~6 K. We have studied the low-lying magnetic excitations in this phase within the kagome plane. Despite the complexity of the system at higher temperatures, linear spin-wave theory describes most of the quantitative detail of the inelastic neutron measurements. Our results show two spin-wave branches, the higher energy of which displays finite spin-wave lifetimes well below Tc, and negligible magnetic exchange coupling between Co moments on the spine sites.Comment: 4 pages and 4 figure
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