177 research outputs found

    Modelling the resilience of forage crop production to future climate change in the dairy regions of southeastern Australia using APSIM

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    A warmer and potentially drier future climate is likely to influence the production of forage crops on dairy farms in The southeast dairy regions of Australia. Biophysical modelling was undertaken to explore the resilience of forage production of individual forage crops to scalar increases in temperature, atmospheric carbon dioxide (CO2) concentration and changes in daily rainfall. The model APSIM was adapted to reflect species specific responses to growth under elevated atmospheric CO2 concentrations. It was then used to simulate 40 years of production of forage wheat, oats, annual ryegrass, maize grown for silage, forage sorghum, forage rape and alfalfa grown at three locations in southeast Australia with increased temperature scenarios (1, 2, 3 and 4 °C of warming) and atmospheric CO2 concentration (435, 535, 640 and 750 ppm) and decreasing rainfall scenarios (10, 20 or 30% less rainfall). At all locations positive increases in DM yield compared with the baseline climate scenario were predicted for lucerne (2·6–93·2% increase), wheat (8·9-37·4% increase), oats (6·1–35·9% increase) and annual ryegrass (9·7–66·7% increase) under all future climate scenarios. The response of forage rape and forage sorghum varied between location and climate change scenario. At all locations, maize was predicted to have a minimal change in yield under all future climates (between a 2·6% increase and a 6·8% decrease). The future climate scenarios altered the seasonal pattern of forage supply for wheat, oats and lucerne with an increase in forage produced during winter. The resilience of forage crops to climate change indicates that they will continue to be an important component of dairy forage production in southeastern Australia

    Berezin Quantization of Gauged WZW and Coset Models

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    Gauged WZW and coset models are known to be useful to prove holomorphic factorization of the partition function of WZW and coset models. In this note we show that these gauged models can be also important to quantize the theory in the context of the Berezin formalism. For gauged coset models Berezin quantization procedure also admits a further holomorphic factorization in the complex structure of the moduli space.Comment: 15+1 pages, no figures, revte

    Climate change effects on pasture-based dairy systems in south-eastern Australia

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    Increases in temperature, along with possible decreases in rainfall will influence the production of forage on Australian dairy farms. A biophysical simulation study was undertaken to compare the performance of perennial pastures and annual forage cropping systems under historical and two possible future climate scenarios for three key dairy locations of south-eastern Australia. Pastures and forage cropping systems were simulated with the biophysical models DairyMod and APSIM, respectively for a location with a heavy reliance on irrigation (Dookie, Victoria), a location with a partial reliance on irrigation (Elliott, Tasmania) and a dryland location (Terang, Victoria). The historical climate scenario (baseline scenario) had no augmentation to climate data and an atmospheric CO2 concentration of 380 ppm, while the two future climate scenarios had either a 1oC increase in temperatures (with an atmospheric CO2 concentration of 435 ppm) and a concurrent 10% decrease in rainfall (+1/-10 scenario) or a 2oC increase in temperatures (with an atmospheric CO2 concentration of 535 ppm) and a concurrent 20% decrease in rainfall and (+2/-20 scenario). Mean annual dry matter (DM) yields (t DM/ha) at Dookie of the forage cropping options and the pasture systems increased under both the future climate scenarios but more irrigation was required. At Terang, the forage cropping systems increased yield while the yield of the pasture systems decreased under the future climate senarious. At Elliott, irrigated pastures and cropping systems increase yield while there was minimal or a negative impact on dryland pastures and cropping systems yields under the futre climate senarious. At all three locations forage production in the colder months of the year increased with a decrease in production during the warmer months. This study indicates that double cropping and irrigated pasture systems at all three locations appear resilient to projected changes in climate, however, for irrigated systems this assumes a reliable supply of irrigation water. The systems implications of how a shift in the seasonality of forage supply within these options impacts on the farm system as a whole warrants further investigation

    Hidden Symmetries and Integrable Hierarchy of the N=4 Supersymmetric Yang-Mills Equations

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    We describe an infinite-dimensional algebra of hidden symmetries of N=4 supersymmetric Yang-Mills (SYM) theory. Our derivation is based on a generalization of the supertwistor correspondence. Using the latter, we construct an infinite sequence of flows on the solution space of the N=4 SYM equations. The dependence of the SYM fields on the parameters along the flows can be recovered by solving the equations of the hierarchy. We embed the N=4 SYM equations in the infinite system of the hierarchy equations and show that this SYM hierarchy is associated with an infinite set of graded symmetries recursively generated from supertranslations. Presumably, the existence of such nonlocal symmetries underlies the observed integrable structures in quantum N=4 SYM theory.Comment: 24 page

    Performance of the new SPS beam position orbit system (MOPOS)

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    The orbit and trajectory measurement system COPOS of the CERN SPS accelerator has been in operation since the construction of the machine in 1976. Over the years the system has been slightly modified in order to follow the evolving demands of the machine, in particular for its operation as a p-pbar collider and, since 1991, for the acceleration of heavy ions. In 1995 the performance of the system was reviewed and the following shortcomings were identified: - lack of turn-by-turn position measurements due to the 1ms integration time of the voltage to frequency converters used for the analogue to digital conversion (to be compared with a revolution time of 23 ms), - ageing effects on the 200 MHz resonating input filters, which had over the years drifted out of tolerance. As a consequence the signal to noise ratio, the linearity and the absolute precision were affected, - the calibration system based on electromechanical relays had become very unreliable, such that frequent calibrations were no longer possible, - a remote diagnostic for the observation of timing signals relative to the beam signals was missing. For the above reasons a large-scale upgrade program was launched, the results of which are described in the following sections

    Alignment of the ISAC-II Medium Beta Cryomodule with a Wire Monitoring System

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    Publisher Summary This chapter discusses a system that has been designed to monitor changes in the alignment of the cavities and solenoids during pump out and cool down. TRIUMF is developing ISAC-II, a superconducting (SC) linac. It will comprise 9 cryomodules with a total of 48 niobium cavities and 12 SC solenoids. They must remain aligned at liquid He temperatures: cavities to ±400 μm and solenoids to ±200 μm after a vertical contraction of ∼4 mm. A wire position monitor (WPM) system based on a TESLA design measures the signals induced in stripline pickups by a 215 MHz signal carded by a position reference wire. The sensors, one per cavity and two per solenoid, monitor their motion during pre-alignment, pumping, and cool down. System accuracy is ∼7 μm. The device is giving a wealth of information over and above the data collected with the installed optical targets. The use of optical targets involves personnel and the readings can be taken only periodically. Conversely the WPM data is monitored continuously providing detailed data that is extremely valuable to help characterize a new structure

    The Topological B-model on a Mini-Supertwistor Space and Supersymmetric Bogomolny Monopole Equations

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    In the recent paper hep-th/0502076, it was argued that the open topological B-model whose target space is a complex (2|4)-dimensional mini-supertwistor space with D3- and D1-branes added corresponds to a super Yang-Mills theory in three dimensions. Without the D1-branes, this topological B-model is equivalent to a dimensionally reduced holomorphic Chern-Simons theory. Identifying the latter with a holomorphic BF-type theory, we describe a twistor correspondence between this theory and a supersymmetric Bogomolny model on R^3. The connecting link in this correspondence is a partially holomorphic Chern-Simons theory on a Cauchy-Riemann supermanifold which is a real one-dimensional fibration over the mini-supertwistor space. Along the way of proving this twistor correspondence, we review the necessary basic geometric notions and construct action functionals for the involved theories. Furthermore, we discuss the geometric aspect of a recently proposed deformation of the mini-supertwistor space, which gives rise to mass terms in the supersymmetric Bogomolny equations. Eventually, we present solution generating techniques based on the developed twistorial description together with some examples and comment briefly on a twistor correspondence for super Yang-Mills theory in three dimensions.Comment: 55 pages; v2: typos fixed, published versio

    Strangers of the north: South Asians, cricket and the culture of ‘Yorkshireness’

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    As a county, Yorkshire is what Wagg and Russell refer to as a ‘cultural region’: an imagined space, where culture is constructed, refined and articulated by a set of discursive relationships between local populations and a whole range of cultural forms. In this context however, culture is conceived as something which belongs to, and is only accessible by, certain groups of people. Our focus in this article is on the culture of Yorkshire cricket. Historically, Yorkshire cricket has been linked with white male privilege and some studies have shown that people within Yorkshire take a degree of pride in this. Consequently, the county and its cricket club have faced frequent accusations from minority ethnic communities of inveterate and institutionalised racism. Drawing upon Bauman’s notion of ‘liquid modernity’, we argue that the processes of deregulation and individualisation championed by New Right policies have led to a divorce between power and politics, a corner stone of the old solid modern world. This in turn has led to an erosion of the state, causing individuals to navigate turbulent life projects which are consistently haunted by the spectres of fear and insecurity. Such an environment has caused cricket to be pushed further behind gated social spaces, in an attempt to maintain a semblance of ‘community’

    Sustained alternate-day fasting potentiates doxorubicin cardiotoxicity

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    Fasting strategies are under active clinical investigation in patients receiving chemotherapy. Prior murine studies suggest that alternate-day fasting may attenuate doxorubicin cardiotoxicity and stimulate nuclear translocation of transcription factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis. In this study, human heart tissue from patients with doxorubicin-induced heart failure demonstrated increased nuclear TFEB protein. In mice treated with doxorubicin, alternate-day fasting or viral TFEB transduction increased mortality and impaired cardiac function. Mice randomized to alternate-day fasting plus doxorubicin exhibited increased TFEB nuclear translocation in the myocardium. When combined with doxorubicin, cardiomyocyte-specific TFEB overexpression provoked cardiac remodeling, while systemic TFEB overexpression increased growth differentiation factor 15 (GDF15) and caused heart failure and death. Cardiomyocyte TFEB knockout attenuated doxorubicin cardiotoxicity, while recombinant GDF15 was sufficient to cause cardiac atrophy. Our studies identify that both sustained alternate-day fasting and a TFEB/GDF15 pathway exacerbate doxorubicin cardiotoxicity
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