37,706 research outputs found

    Arbitrage, market definition and monitoring a time series approach

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    This article considers the application to regional price data of time series methods to test stationarity, multivariate cointegration and exogeneity. The discovery of stationary price differentials in a bivariate setting implies that the series are rendered stationary by capturing a common trend and we observe through this mechanism long-run arbitrage. This is indicative of a broader market definition and efficiency. The problem is considered in relation to more than 700 weekly data points on gasoline prices for three regions of the US and similarly calibrated simulated series. The discovery of a single common trend is consistent with competitive pricing and a broad market definition, but the finding of a single weakly exogenous variable affects this conclusion

    Examination of the impact and effectiveness of herd health and welfare assessment in im-proving animal welfare on organic dairy farms, using qualitative interviews.

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    During winter 2002-03, 15 organic dairy farms in SW England participated in a herd health and welfare assessment and benchmarking study. A second assessment was carried out on 14 of the original 15 farms and on 14 new farms during winter 2003-04. The effectiveness of the herd health and welfare as-sessments and benchmarking in delivering animal health and welfare improvements was investigated by means of qualitative research interviews. The inter-views were conducted between August and November 2004. The average length of interview was one hour and fifteen minutes. Five common themes were iden-tified and headed ‘Sensitivities and misgivings’; ‘Ac-ceptability of scoring methodology and indicators assessed’; ‘Raised awareness and motivation to im-prove’; ‘Veterinary support and herd health planning’ and ‘Value of assessment and benchmarking’. It was apparent that farmers, who took part voluntarily in the study, took the results of the herd health and welfare assessments very seriously and were clearly motivated by the process. The main focus for change was related to housing issues. The main constraints to welfare improvement were a shortage of finance to affect change beyond relatively simple alterations and a lack of information on the identification of changes likely to improve animal welfare in given situations

    Student perceptions of the aims of education in an independent school and the differing value priorities expressed. a q-methodological study

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    This research gathered student perceptions of the aims of their senior school education in an independent school. The data was collected using Q-methodology. Participants completed the same Q-sort twice. The Q-sorts were factor analysed resulting in three factors for Q-sort 1 expressing students’ own perceptions; these were titled: Future personal success, Enjoyment and care, and Empowerment. Four factors were retained from Q-sort 2, where students completed the same Q-sort from a hypothetical teacher’s point of view; these were titled: Social cohesion and enjoyment, Academic importance, Fulfilling potential, and Personal development and wider societal benefits. Literature around the aims of education, the statements for the Q-set and the resulting factors were analysed using Schwartz’s model of basic human values and pan-cultural baseline of value priorities as an analytical lens. This showed that although the aims of education align with Schwartz's findings of societal values, the participants in this study expressed differing value priorities to those in Schwartz’s pan-cultural baseline. Through this lens, it was found that student perceptions of the aims of their education in this independent school focus mainly on the value of self-determination, in line with Schwartz’s findings in societies. Differing from Schwartz’s findings in societies, however, is the high prevalence of self-enhancement and hedonism values in the students’ perceptions of the aims of their education. Also differing majorly from Schwartz’s findings is the low prevalence of benevolence and universalism in the students’ perceptions of the aims of their education. The study concludes that further research into the values of independently educated students would provide further valuable insights, and that schools should consider carefully the values that may be enhanced or demoted through certain educational activities

    Representation in Westminster in the 1990s : The ghost of Edmund Burke

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    Why are 'trustee' notions of representation still invoked in the UK House of Commons in the 1990s? In answering this question this article analyses the premises of Burkean theory and the arguments that these premises are of little relevance in the late twentieth century. Despite these dismissals of trusteeship, Burkean ideas are still articulated in the Commons some 200 years after they were first voiced. The idea of trusteeship can prove extremely useful to justify the actions of representatives when those actions conflict with constituency 'opinion', party policy or the wishes of interest groups. Examples of the occasions when Burkean notions have been invoked in the 1990s are provided

    A combined R-matrix eigenstate basis set and finite-differences propagation method for the time-dependent Schr\"{od}dinger equation: the one-electron case

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    In this work we present the theoretical framework for the solution of the time-dependent Schr\"{o}dinger equation (TDSE) of atomic and molecular systems under strong electromagnetic fields with the configuration space of the electron's coordinates separated over two regions, that is regions II and IIII. In region II the solution of the TDSE is obtained by an R-matrix basis set representation of the time-dependent wavefunction. In region IIII a grid representation of the wavefunction is considered and propagation in space and time is obtained through the finite-differences method. It appears this is the first time a combination of basis set and grid methods has been put forward for tackling multi-region time-dependent problems. In both regions, a high-order explicit scheme is employed for the time propagation. While, in a purely hydrogenic system no approximation is involved due to this separation, in multi-electron systems the validity and the usefulness of the present method relies on the basic assumption of R-matrix theory, namely that beyond a certain distance (encompassing region II) a single ejected electron is distinguishable from the other electrons of the multi-electron system and evolves there (region II) effectively as a one-electron system. The method is developed in detail for single active electron systems and applied to the exemplar case of the hydrogen atom in an intense laser field.Comment: 13 pages, 6 figures, submitte

    Rules for Minimal Atomic Multipole Expansion of Molecular Fields

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    A non-empirical minimal atomic multipole expansion (MAME) defines atomic charges or higher multipoles that reproduce electrostatic potential outside molecules. MAME eliminates problems associated with redundancy and with statistical sampling, and produces atomic multipoles in line with chemical intuition.Comment: 3.5 pages, 3 color PS figures embedde

    Maclisp extensions

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    A common subset of selected facilities available in Maclisp and its derivatives (PDP-10 and Multics Maclisp, Lisp Machine Lisp (Zetalisp), and NIL) is decribed. The object is to add in writing code which can run compatibly in more than one of these environments
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