16,387 research outputs found

    Feeding a Population: Agricultural Education Priorities in Haitian History

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    The nation of Haiti has experienced a long history of poverty and of tests to its economic development. Among its priorities has been the establishment of an effective educational system. While educational standards remain high, the area of agricultural education—necessary for Haiti’s economy as well as nutritional subsistence—has met with unique challenges. This paper examines analyses and programming policies of the past in order to illuminate contemporary circumstances

    How does one do a Practice-Based PhD in Filmmaking?

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    This paper seeks to explore the issues raised by the process of engaging in a practice-based PhD in Filmmaking. As a sole practitioner the screenwriting doctoral student is able to explore her practice through the development of a screenplay, but what of the potential doctoral students who may wish to explore their specialist and professional filmmaking practices but who are unable to operate as sole practitioners, because of the collaborative requirements of the professional filmmaking model. Using the experience of the screenwriting doctoral investigation, and particularly the exploration of the relationship between methodology, exegesis and the creative artefact, we explore a potential model that would enable all filmmaking specialists to engage in doctoral research. Art students engaging in practice-based doctoral research do so in an environment formed by Government requirements that demand cultural, environmental and economic impacts as well as a methodology that to a large extent is formed by social science measures of value. Using this framework as a starting point we attempted to identify a suitable model that would enable filmmakers to undertake practice-based doctoral research

    Automatic linearity detection

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    Given a function, or more generally an operator, the question "Is it linear?" seems simple to answer. In many applications of scientific computing it might be worth determining the answer to this question in an automated way; some functionality, such as operator exponentiation, is only defined for linear operators, and in other problems, time saving is available if it is known that the problem being solved is linear. Linearity detection is closely connected to sparsity detection of Hessians, so for large-scale applications, memory savings can be made if linearity information is known. However, implementing such an automated detection is not as straightforward as one might expect. This paper describes how automatic linearity detection can be implemented in combination with automatic differentiation, both for standard scientific computing software, and within the Chebfun software system. The key ingredients for the method are the observation that linear operators have constant derivatives, and the propagation of two logical vectors, \ell and cc, as computations are carried out. The values of \ell and cc are determined by whether output variables have constant derivatives and constant values with respect to each input variable. The propagation of their values through an evaluation trace of an operator yields the desired information about the linearity of that operator

    Probabilistic Risk Analysis and Margin Process for a Flexible Thermal Protection System

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    Atmospheric entry vehicle thermal protection systems are margined due to the uncertainties that exist in entry aeroheating environments and the thermal response of the materials and structures. Entry vehicle thermal protections systems are traditionally over-margined for the heat loads that are experienced along the entry trajectory by designing to survive stacked worst-case scenarios. Additionally, the conventional heat shield design and margin process offers very little insight into the risk of over-temperature during flight and the corresponding reliability of the heat shield performance. A probabilistic margin process can be used to appropriately margin the thermal protection system based on rigorously calculated risk of failure. This probabilistic margin process allows engineers to make informed aeroshell design, entry-trajectory design, and risk trades while preventing excessive margin from being applied. This study presents the methods of the probabilistic margin process and how the uncertainty analysis is used to determine the reliability of the entry vehicle thermal protection system and associated risks of failure

    The chebop system for automatic solution of differential equations

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    In MATLAB, it would be good to be able to solve a linear differential equation by typing u = L\f, where f, u, and L are representations of the right-hand side, the solution, and the differential operator with boundary conditions. Similarly it would be good to be able to exponentiate an operator with expm(L) or determine eigenvalues and eigenfunctions with eigs(L). A system is described in which such calculations are indeed possible, based on the previously developed chebfun system in object-oriented MATLAB. The algorithms involved amount to spectral collocation methods on Chebyshev grids of automatically determined resolution

    Third sector organizations and earthquake recovery planning in Christchurch, New Zealand

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    On September 4, 2010, an earthquake struck rural Canterbury and the most deadly of over 2,000 aftershocks devastated the Christchurch Central Business District on February 22, 2011 (Ardagh et al. 2012). Questions have arisen regarding population dynamics (Love 2011), marginalized groups, health and social care, and overall recovery efforts. Addressing some of these concerns are various non-profit, non-governmental, and faith based groups, collectively referred to as Third Sector Organizations (TSOs). By providing an alternative to and back-stopping government and private health and social services, TSOs are able to build resiliency following a natural disaster, and are especially able to identify and address unmet needs within their target audiences and maintain a sense of community within their operating areas. The nature of community recovery, also changes the role of TSOs in formal and grassroots efforts over time. In New Zealand, TSOs have shared community health burdens with government and private practices since the 1990s (Larner and Craig 2005) and have championed healthcare policy measures for ethnic minorities (Came 2014). Nevertheless, the earthquakes have presented challenges to TSOs. An inventory of 92 TSOs four months after the earthquakes, 106 one year after, and 454 two years after by Carlton and Vallance (2013) shows that although many TSOs have emerged to address earthquake related issues, other TSOs may have been unable to re-establish themselves outside areas with earthquake damage found to be too severe to inhabit by the Canterbury Earthquake Recovery Authority (CERA). Others reported “burn-out” and 52 were inactive or closed because of shifting needs during recovery. This research identifies shared experiences across the third sector in Canterbury to illuminate shifting roles in mid to long-term earthquake recovery

    Photocatalytic antimicrobial activity of thin surface films of TiO2, CuO and TiO2 /CuO dual layers on Escherichia coli and bacteriophage T4

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    TiO2 coated surfaces are increasingly studied for their ability to inactivate microorganisms. The activity of glass coated with thin films of TiO2, CuO and hybrid CuO/TiO2 prepared by atmospheric Chemical Vapour Deposition (Ap-CVD) and TiO2 prepared by a sol-gel process was investigated using the inactivation of bacteriophage T4 as a model for inactivation of viruses. The chemical oxidising activity was also determined by measuring stearic acid oxidation. The results showed that the rate of inactivation of bacteriophage T4 increased with increasing chemical oxidising activity with the maximum rate obtained on highly active sol-gel preparations. However these were delicate and easily damaged unlike the Ap-CVD coatings. Inactivation rates were highest on CuO and CuO/TiO2 which had the lowest chemical oxidising activities. The inactivation of T4 was higher than that of Escherichia coli on low activity surfaces. The combination of photocatalysis and toxicity of copper acted synergistically to inactivate bacteriophage T4 and retained some selfcleaning activity. The presence of phosphate ions slowed inactivation but NaCl had no effect. The results show that TiO2/CuO coated surfaces are highly antiviral and may have applications in the food and healthcare industries
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