5,219 research outputs found
Truth Table Invariant Cylindrical Algebraic Decomposition by Regular Chains
A new algorithm to compute cylindrical algebraic decompositions (CADs) is
presented, building on two recent advances. Firstly, the output is truth table
invariant (a TTICAD) meaning given formulae have constant truth value on each
cell of the decomposition. Secondly, the computation uses regular chains theory
to first build a cylindrical decomposition of complex space (CCD) incrementally
by polynomial. Significant modification of the regular chains technology was
used to achieve the more sophisticated invariance criteria. Experimental
results on an implementation in the RegularChains Library for Maple verify that
combining these advances gives an algorithm superior to its individual
components and competitive with the state of the art
Radiological Characterization of a Uranium Processing Facility
This document describes the plan that was developed and is being carried out at the Oak Ridge Y-12 Plant to provide data needed for radiological characterization of the site in anticipation of new posting regulations provided in Title 10, Code of Federal Regulations, Part 835, as codified from Volume 58, Number 238 of the Federal Register. The characterization plan addresses the entire site in terms of three categories: 1) Outdoor paved surfaces, 2) buildings, and 3) outdoor non-paved surfaces. Instruments chosen for use in this project are described, as well as survey techniques and the data management scheme. A quantitative assessment of the effectiveness and adequacy of the survey plan for paved surfaces is also provided
Generalised Elliptic Functions
We consider multiply periodic functions, sometimes called Abelian functions,
defined with respect to the period matrices associated with classes of
algebraic curves. We realise them as generalisations of the Weierstras
P-function using two different approaches. These functions arise naturally as
solutions to some of the important equations of mathematical physics and their
differential equations, addition formulae, and applications have all been
recent topics of study.
The first approach discussed sees the functions defined as logarithmic
derivatives of the sigma-function, a modified Riemann theta-function. We can
make use of known properties of the sigma function to derive power series
expansions and in turn the properties mentioned above. This approach has been
extended to a wide range of non hyperelliptic and higher genus curves and an
overview of recent results is given.
The second approach defines the functions algebraically, after first
modifying the curve into its equivariant form. This approach allows the use of
representation theory to derive a range of results at lower computational cost.
We discuss the development of this theory for hyperelliptic curves and how it
may be extended in the future.Comment: 16 page
Deriving bases for Abelian functions
We present a new method to explicitly define Abelian functions associated
with algebraic curves, for the purpose of finding bases for the relevant vector
spaces of such functions. We demonstrate the procedure with the functions
associated with a trigonal curve of genus four. The main motivation for the
construction of such bases is that it allows systematic methods for the
derivation of the addition formulae and differential equations satisfied by the
functions. We present a new 3-term 2-variable addition formulae and a complete
set of differential equations to generalise the classic Weierstrass identities
for the case of the trigonal curve of genus four.Comment: 35page
Unmasking quality: exploring meanings of health by doing art
This paper arises from a presentation at the ‘Quality in Healthcare’ symposium at Cumberland Lodge, England, in 2013. MK, CR and SH conceived the paper and led the writing of the manuscript. JF, JL-D, AC, DE contributed substantially to the intellectual content of the paper through providing critical commentary and interpretation. All authors read and approved the final manuscript
Far-infrared spectra of CO2 clathrate hydrate frosts
As a product of our interest in remote sensing of planetary ices, frost samples of CO2 clathrate hydrate were grown by depositing water vapor on a cooled surface and pressurizing the resulting water frost with CO2 gas. At pressures above the dissociation pressure of the clathrate, the samples exhibit an absorption peak at 75 cm (sup -1). At pressures below the dissociation pressure, the peak disappears. Since the free CO2 molecule does not have rotational or vibrational absorption in this region, the absorption is attributed to a CO2 rattling mode within a clathrate cage
Reviewing research evidence and the case of participation in sport and physical recreation by black and minority ethnic communities
The paper addresses the implications of using the process of systematic review in the many areas of leisure where there is a dearth of material that would be admitted into conventional Cochrane Reviews. This raises important questions about what constitutes legitimate knowledge, questions that are of critical import not just to leisure scholars, but to the formulation of policy. The search for certainty in an area that lacks conceptual consensus results in an epistemological imperialism that takes a geocentric form. While clearly, there is a need for good research design whatever the style of research, we contend that the wholesale rejection of insightful research is profligate and foolhardy. A mechanism has to be found to capitalise on good quality research of whatever form. In that search, we draw upon our experience of conducting a review of the material available on participation in sport and physical recreation by people from Black and minority ethnic groups. The paper concludes with a proposal for a more productive review process that makes better use of the full panoply of good quality research available. © 2012 © 2012 Taylor & Francis
Capital structure and its determinants in the United Kingdom – a decompositional analysis
Prior research on capital structure by Rajan and Zingales (1995) suggests that the level of gearing in UK companies is positively related to size and tangibility, and negatively correlated with profitability and the level of growth opportunities. However, as argued by Harris and Raviv (1991), 'The interpretation of results must be tempered by an awareness of the difficulties involved in measuring both leverage and the explanatory variables of interest'. In this study the focus is on the difficulties of measuring gearing, and the sensitivity of Rajan and Zingales' results to variations in gearing measures are tested. Based on an analysis of the capital structure of 822 UK companies, Rajan and Zingales' results are found to be highly definitional-dependent. The determinants of gearing appear to vary significantly, depending upon which component of debt is being analysed. In particular, significant differences are found in the determinants of long- and short-term forms of debt. Given that trade credit and equivalent, on average, accounts for more than 62% of total debt, the results are particularly sensitive to whether such debt is included in the gearing measure. It is argued, therefore, that analysis of capital structure is incomplete without a detailed examination of all forms of corporate debt
Climate change adaptation planning and cross-sectoral policy coherence in southern Africa
The post-2015 development agenda requires policy coherence, where achievement
of development goals in one sector does not undermine the achievement of the
goals of another. It also recognises that cross-cutting issues like adaptation
to climate change need to be mainstreamed across multiple sectors. This paper
presents a policy analysis using the cases of Malawi, Tanzania and Zambia. It
analyses the water management and agricultural strategies and approaches
identified in a variety of policies and plans. These include national sector
policies for water and agriculture, National Development Plans, and climate
change policies and strategies, including National Adaptation Programmes of
Action and the Intended Nationally Determined Contributions submitted prior to
the 2015 United Nations Framework Convention on Climate Change Conference of
the Parties. It assesses the extent to which policies are coherent with one
another with regard to their treatment of climate change adaptation using
Qualitative Document Analysis. Findings identify that sector policies show
some degree of cross-thematic coherence, in particular around their
acknowledgement of the importance to address disaster management of floods and
droughts. However, policy statements are typified by a relative lack of
recognition of the need to develop supporting instruments and strategies that
address climate adaptation needs over longer timeframes. Climate change
policies explicitly call for significant investment in adaptation from the
international community. Where coherence between sector and climate policies
and strategies is strongest, the more recent climate policies largely
repackage existing sectoral policy statements. These findings can be
understood in the context of the uncertainty of climate change impacts for the
longer term (for which a wider variety of adaptations are identified),
alongside more event-driven disaster management planning where the impacts are
more immediate and obviously evident. This prioritisation is also linked to
development needs and the short-term nature of political cycles and economic
gain. For climate-resilient policy decision-making to make further headway, we
argue that governments need to embrace cross-sectoral planning more pro-
actively in order to foster greater policy coherence and to deliver more
climate resilient agriculture and water management
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