1,260 research outputs found

    The Design Education Myth

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    There are not many former Handicraft departments that have not changed their names into something that implies a new emphasis.Using various permutations of currently used words like 'Design', 'Craft', 'Technology', 'Technical' and 'Creative', each school has carefully tried to present its particular interpretation of the kind of education their title implies.Yet when one tries to see the extent to which the title gives a true indication of what is happening in the school, it becomes clear that the ones that have tended to avoid, or be reticent about using the word Design in their Departmental title, will probably be the ones who, in a dozen or so years, will have been seen to have got it about right.For the chances are, by then Craft and Design and Technology Education, or Design Education for short, will have all but died. In spite of huge investment and a massive propaganda campaign to get it going in the schools, it has hardly even begun to establish itself

    Theoretical Studies of Spectroscopic Line Mixing in Remote Sensing Applications

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    The phenomenon of collisional transfer of intensity due to line mixing has an increasing importance for atmospheric monitoring. From a theoretical point of view, all relevant information about the collisional processes is contained in the relaxation matrix where the diagonal elements give half-widths and shifts, and the off-diagonal elements correspond to line interferences. For simple systems such as those consisting of diatom-atom or diatom-diatom, accurate fully quantum calculations based on interaction potentials are feasible. However, fully quantum calculations become unrealistic for more complex systems. On the other hand, the semi-classical Robert-Bonamy (RB) formalism, which has been widely used to calculate half-widths and shifts for decades, fails in calculating the off-diagonal matrix elements. As a result, in order to simulate atmospheric spectra where the effects from line mixing are important, semi-empirical fitting or scaling laws such as the ECS (Energy-Corrected Sudden) and IOS (Infinite-Order Sudden) models are commonly used. Recently, while scrutinizing the development of the RB formalism, we have found that these authors applied the isolated line approximation in their evaluating matrix elements of the Liouville scattering operator given in exponential form. Since the criterion of this assumption is so stringent, it is not valid for many systems of interest in atmospheric applications. Furthermore, it is this assumption that blocks the possibility to calculate the whole relaxation matrix at all. By eliminating this unjustified application, and accurately evaluating matrix elements of the exponential operators, we have developed a more capable formalism. With this new formalism, we are now able not only to reduce uncertainties for calculated half-widths and shifts, but also to remove a once insurmountable obstacle to calculate the whole relaxation matrix. This implies that we can address the line mixing with the semi-classical theory based on interaction potentials between molecular absorber and molecular perturber. We have applied this formalism to address the line mixing for Raman and infrared spectra of molecules such as N2, C2H2, CO2, NH3, and H2O. By carrying out rigorous calculations, our calculated relaxation matrices are in good agreement with both experimental data and results derived from the ECS model

    Joint research project on the aquatic ecotoxicity of organo-aluminium: Chemical reactions. First interim report

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    The overall goal of the joint research project is to relate the chemical reactions involved in the formation of organo-aluminium complexes under acid conditions to their toxic effects on the physiology of aquatic organisms. Finally, this research is intended to predict toxic effects arising from acidity and aluminium under varying environmental conditions. This interim report examines the chemical modelling of ion-binding by humic substances where a computer model has been developed and is being tested using field data, and conditions required for the precipitation of aluminium in surface waters

    Active Sampling-based Binary Verification of Dynamical Systems

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    Nonlinear, adaptive, or otherwise complex control techniques are increasingly relied upon to ensure the safety of systems operating in uncertain environments. However, the nonlinearity of the resulting closed-loop system complicates verification that the system does in fact satisfy those requirements at all possible operating conditions. While analytical proof-based techniques and finite abstractions can be used to provably verify the closed-loop system's response at different operating conditions, they often produce conservative approximations due to restrictive assumptions and are difficult to construct in many applications. In contrast, popular statistical verification techniques relax the restrictions and instead rely upon simulations to construct statistical or probabilistic guarantees. This work presents a data-driven statistical verification procedure that instead constructs statistical learning models from simulated training data to separate the set of possible perturbations into "safe" and "unsafe" subsets. Binary evaluations of closed-loop system requirement satisfaction at various realizations of the uncertainties are obtained through temporal logic robustness metrics, which are then used to construct predictive models of requirement satisfaction over the full set of possible uncertainties. As the accuracy of these predictive statistical models is inherently coupled to the quality of the training data, an active learning algorithm selects additional sample points in order to maximize the expected change in the data-driven model and thus, indirectly, minimize the prediction error. Various case studies demonstrate the closed-loop verification procedure and highlight improvements in prediction error over both existing analytical and statistical verification techniques.Comment: 23 page

    Regression with Linear Factored Functions

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    Many applications that use empirically estimated functions face a curse of dimensionality, because the integrals over most function classes must be approximated by sampling. This paper introduces a novel regression-algorithm that learns linear factored functions (LFF). This class of functions has structural properties that allow to analytically solve certain integrals and to calculate point-wise products. Applications like belief propagation and reinforcement learning can exploit these properties to break the curse and speed up computation. We derive a regularized greedy optimization scheme, that learns factored basis functions during training. The novel regression algorithm performs competitively to Gaussian processes on benchmark tasks, and the learned LFF functions are with 4-9 factored basis functions on average very compact.Comment: Under review as conference paper at ECML/PKDD 201

    Omacetaxine may have a role in chronic myeloid leukaemia eradication through downregulation of Mcl-1 and induction of apoptosis in stem/progenitor cells

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    Chronic myeloid leukaemia (CML) is maintained by a rare population of tyrosine kinase inhibitor (TKI)-insensitive malignant stem cells. Our long-term aim is to find a BcrAbl-independent drug that can be combined with a TKI to improve overall disease response in chronic-phase CML. Omacetaxine mepesuccinate, a first in class cetaxine, has been evaluated by clinical trials in TKI-insensitive/resistant CML. Omacetaxine inhibits synthesis of anti-apoptotic proteins of the Bcl-2 family, including (myeloid cell leukaemia) Mcl-1, leading to cell death. Omacetaxine effectively induced apoptosis in primary CML stem cells (CD34<sup>+</sup>38<sup>lo</sup>) by downregulation of Mcl-1 protein. In contrast to our previous findings with TKIs, omacetaxine did not accumulate undivided cells <i>in vitro</i>. Furthermore, the functionality of surviving stem cells following omacetaxine exposure was significantly reduced in a dose-dependant manner, as determined by colony forming cell and the more stringent long-term culture initiating cell colony assays. This stem cell-directed activity was not limited to CML stem cells as both normal and non-CML CD34<sup>+</sup> cells were sensitive to inhibition. Thus, although omacetaxine is not leukaemia stem cell specific, its ability to induce apoptosis of leukaemic stem cells distinguishes it from TKIs and creates the potential for a curative strategy for persistent disease

    A far-wing line shape theory which satisfies the detailed balance principle

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    A far-wing theory in which the validity of the detailed balance principle is maintained in each step of the derivation is presented. The role of the total density matrix including the initial correlations is analyzed rigorously. By factoring out the rapidly varying terms in the complex-time development operator in the interaction representation, better approximate expressions can be obtained. As a result, the spectral density can be expressed in terms of the line-coupling functions in which two coupled lines are arranged symmetrically and whose frequency detunings are omega - 1/2(omega(sub ji) + omega (sub j'i'). Using the approximate values omega - omega(sub ji) results in expressions that do not satisfy the detailed balance principle. However, this principle remains satisfied for the symmetrized spectral density in which not only the coupled lines are arranged symmetrically, but also the initial and final states belonging to the same lines are arranged symmetrically as well

    Release and Establishment of Megamelus scutellaris (Hemiptera: Delphacidae) on Waterhyacinth in Florida

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    More than 73,000 Megamelus scutellaris (Hemiptera: Delphacidae) were released in Florida over a 2 to 3 yr period at 10 sites in an attempt to establish sustainable populations on waterhyacinth, Eichhornia crassipes Mart. Solms (Commelinales: Pontederiaceae). Insect populations persisted at most sites including those furthest north and consecutive overwintering was confirmed in as many as three times at some sites. Establishment appeared to be promoted at sites with some cover or shading compared to open areas. Insects readily dispersed over short distances which made detection and monitoring difficultFil: Tipping, Philip W.. Invasive Plant Research Laboratory; Estados UnidosFil: Sosa, Alejandro Joaquín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación para el Estudio de Especies Invasivas; ArgentinaFil: Pokorny, Eileen N.. Invasive Plant Research Laboratory; Estados UnidosFil: Foley, Jeremiah. Invasive Plant Research Laboratory; Estados UnidosFil: Schmitz, Don C.. Florida Fish and Wildlife Conservation Commission; Estados UnidosFil: Lane, Jon S.. U.S. Army Corps of Engineers; Estados UnidosFil: Rodgers, Leroy. South Florida Water Management District; Estados UnidosFil: Mccloud, Lori. St. Johns River Water Management District; Estados UnidosFil: Livingston-Way, Pam. St. Johns River Water Management District; Estados UnidosFil: Cole, Matthew S.. St. Johns River Water Management District; Estados UnidosFil: Nichols, Gary. St. Johns River Water Management District; Estados Unido
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