483 research outputs found

    Ανάλυση και βελτιστοποίηση της επίδοσης cloud εφαρμογών σε διαμοιραζόμενα περιβάλλοντα με προσαρμοστική ανάθεση πόρων

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    Intensive tillage, high fertiliser inputs, and plastic mulch on the soil surface are widely used by vegetable growers. A field investigation was carried out to quantify the impact of alternate land management and fertiliser practices designed to improve offsite water quality on the productivity of vegetable rotations within a sugarcane farming system in a coastal region of subtropical northeast Australia. Successive crops of capsicum and zucchini were grown in summer 2010–2011 and winter 2011, respectively, using four different management practices. These were ‘Conventional’—the current conventional practice using plastic mulch, bare inter-rows, conventional tillage, and commercial fertiliser inputs; ‘Improved’—a modified conventional system using plastic mulch in the cropped area, an inter-row vegetative mulch, zonal tillage, and reduced fertiliser rates; ‘Trash mulch’—using cane trash or forage sorghum residues instead of plastic mulch, with reduced fertiliser rates and minimum or zero tillage; and ‘Vegetative mulch’—using Rhodes grass or forage sorghum residues instead of plastic mulch, with minimum or zero tillage and reduced fertiliser rates. During the second vegetable crop (zucchini), each management practice was split to receive either soil test-based nutrient inputs or a common, luxury rate of nutrient addition. The ’Trash mulch’ and ‘Vegetative mulch’ systems produced up to 43% lower capsicum and zucchini yields than either of the plastic mulch systems. The relative yield difference between trash systems and plastic mulch management systems remained the same for both the soil test-based and high nutrient application strategies, suggesting that factors other than nutrition (e.g., soil temperature) were driving these differences

    Carbon losses in terrestrial hydrological pathways in sugarcane cropping systems of Australia

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    Climate change and carbon (C) sequestration are a major focus of research in the twenty-first century. Globally, soils store about 300 times the amount of C that is released per annum through the burning of fossil fuels (Schulze and Freibauer 2005). Land clearing and introduction of agricultural systems have led to rapid declines in soil C reserves. The recent introduction of conservation agricultural practices has not led to a reversing of the decline in soil C content, although it has minimized the rate of decline (Baker et al. 2007; Hulugalle and Scott 2008). Lal (2003) estimated the quantum of C pools in the atmosphere, terrestrial ecosystems, and oceans and reported a “missing C” component in the world C budget. Though not proven yet, this could be linked to C losses through runoff and soil erosion (Lal 2005) and a lack of C accounting in inland water bodies (Cole et al. 2007). Land management practices to minimize the microbial respiration and soil organic C (SOC) decline such as minimum tillage or no tillage were extensively studied in the past, and the soil erosion and runoff studies monitoring those management systems focused on other nutrients such as nitrogen (N) and phosphorus (P)

    Research students exhibition catalogue 2013

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    This exhibition catalogue showcases the work of current UCA research students at various stages of their research journey. The theme of the exhibition and the one day conference is time - place - space and through their practice the research students examine these concepts and realities

    Quantized Scaling of Growing Surfaces

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    The Kardar-Parisi-Zhang universality class of stochastic surface growth is studied by exact field-theoretic methods. From previous numerical results, a few qualitative assumptions are inferred. In particular, height correlations should satisfy an operator product expansion and, unlike the correlations in a turbulent fluid, exhibit no multiscaling. These properties impose a quantization condition on the roughness exponent χ\chi and the dynamic exponent zz. Hence the exact values χ=2/5,z=8/5\chi = 2/5, z = 8/5 for two-dimensional and χ=2/7,z=12/7\chi = 2/7, z = 12/7 for three-dimensional surfaces are derived.Comment: 4 pages, revtex, no figure

    On the Renormalization of the Kardar-Parisi-Zhang equation

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    The Kardar-Parisi-Zhang (KPZ) equation of nonlinear stochastic growth in d dimensions is studied using the mapping onto a system of directed polymers in a quenched random medium. The polymer problem is renormalized exactly in a minimally subtracted perturbation expansion about d = 2. For the KPZ roughening transition in dimensions d > 2, this renormalization group yields the dynamic exponent z* = 2 and the roughness exponent chi* = 0, which are exact to all orders in epsilon = (2 - d)/2. The expansion becomes singular in d = 4, which is hence identified with the upper critical dimension of the KPZ equation. The implications of this perturbation theory for the strong-coupling phase are discussed. In particular, it is shown that the correlation functions and the coupling constant defined in minimal subtraction develop an essential singularity at the strong-coupling fixed point.Comment: 21 pp. (latex, now texable everywhere, no other changes), with 2 fig

    Transitive quasi-uniform spaces

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    Chapter 1 deals with basic properties of the category of quasi-uniform spaces and its full subcategory Qut of transitive quasi-uniform spaces. Chapter 2 concerns Fletcher's construction. We extend the class of covers to which this construction may be applied and study the functoriality of the construction. The major result is that every right inverse of the forgetful functor Qut--->Top is obtainable by the extended Fletcher construction. In Chapter 3 we characterize pairwise zero dimensional bitopological spaces as those admitting transitive quasi-uniformities. An initiality characterization of pairwise zero dimensional bitopological spaces suggested by Brümmer leads to a description of the coarsest right inverse of the forgetful functor. In Chapter 4 we discuss countably based transitive quasi-uniformities, in that they relate to quasi-metrization. We elaborate on a result of Fletcher and Lindgren (1972) and obtain a bitopological analogue. In Chapter 5 we bring together a number of topics which relate to our previous chapters and point to further questions

    The regional impact of equine youth activities held at the Southern Illinois University Carbondale College of Agricultural Science

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    The SIUC College of Agricultural Science has hosted the Southern Regional 4-H Hippology and Horse Bowl contest for the past two years. During the competition, a short survey will be offered to contestants and leaders to obtain accurate and anonymous feedback regarding the contest and the impact of this event on the regional 4-H members who participate. Specifically, the survey will focus on how the SIUC hosted Hippology and Horse Bowl contest prepares 4-H members for further competitions and if the contest encourages students to pursue an agricultural field, particularly at SIUC. During the organization of the event, number of contestants and 4-H clubs present will be recorded. On March 25th, one survey will be given to contestants to determine effectiveness of the contest in preparation for future competitions in addition to the impact SIUC College of Agricultural Science has on determining future educational paths. The second survey will be directed towards 4-H leaders to gather opinions on content and organization. Both surveys will offer information which the SIUC College of Agricultural Science will utilize for future contests. The results will also illustrate the importance of the College’s activity in the community and the impact of such activities in 4-H youth looking into their educational future. The results will reveal if hosting youth activities is an effective means to bring new students to Southern Illinois University Carbondale and ways to improve the event. Data will be collect on March 25th. The findings will be presented at the Undergraduate Research Foru

    Directed polymers in high dimensions

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    We study directed polymers subject to a quenched random potential in d transversal dimensions. This system is closely related to the Kardar-Parisi-Zhang equation of nonlinear stochastic growth. By a careful analysis of the perturbation theory we show that physical quantities develop singular behavior for d to 4. For example, the universal finite size amplitude of the free energy at the roughening transition is proportional to (4-d)^(1/2). This shows that the dimension d=4 plays a special role for this system and points towards d=4 as the upper critical dimension of the Kardar-Parisi-Zhang problem.Comment: 37 pages REVTEX including 4 PostScript figure

    Google haul out : Earth observation imagery and digital aerial surveys in coastal wildlife management and abundance estimation

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    © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bioscience 67 (2017): 760–768, doi:10.1093/biosci/bix059.As the sampling frequency and resolution of Earth observation imagery increase, there are growing opportunities for novel applications in population monitoring. New methods are required to apply established analytical approaches to data collected from new observation platforms (e.g., satellites and unmanned aerial vehicles). Here, we present a method that estimates regional seasonal abundances for an understudied and growing population of gray seals (Halichoerus grypus) in southeastern Massachusetts, using opportunistic observations in Google Earth imagery. Abundance estimates are derived from digital aerial survey counts by adapting established correction-based analyses with telemetry behavioral observation to quantify survey biases. The result is a first regional understanding of gray seal abundance in the northeast US through opportunistic Earth observation imagery and repurposed animal telemetry data. As species observation data from Earth observation imagery become more ubiquitous, such methods provide a robust, adaptable, and cost-effective solution to monitoring animal colonies and understanding species abundances.We would like to thank generous support from International Fund for Animal Welfare, the Bureau of Ocean Energy, and the Oak Foundation for funding support for the telemetry devices
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