5,389 research outputs found
More efficient Bell inequalities for Werner states
In this paper we study the nonlocal properties of two-qubit Werner states
parameterized by the visibility parameter 0<p<1. New family of Bell
inequalities are constructed which prove the two-qubit Werner states to be
nonlocal for the parameter range 0.7056<p<1. This is slightly wider than the
range 0.7071<p<1, corresponding to the violation of the
Clauser-Horne-Shimony-Holt (CHSH) inequality. This answers a question posed by
Gisin in the positive, i.e., there exist Bell inequalities which are more
efficient than the CHSH inequality in the sense that they are violated by a
wider range of two-qubit Werner states.Comment: 7 pages, 1 figur
Thermoacoustic tomography with variable sound speed
We study the mathematical model of thermoacoustic tomography in media with a
variable speed for a fixed time interval, greater than the diameter of the
domain. In case of measurements on the whole boundary, we give an explicit
solution in terms of a Neumann series expansion. We give necessary and
sufficient conditions for uniqueness and stability when the measurements are
taken on a part of the boundary
Diversity, Dilemmas and Transformation in Post-Compulsory Education: an Introduction to the Special Issue on Work Based Research
As governments recognize the central place of post-compulsory education in regenerating and modernizing the economic and social fabric of society (BIS 2008), it is appropriate for us as educational researchers to question whether this recognition beckons a different role for research in post-compulsory education. Much of this research is work based, using a broad interpretation of this term, and the majority of articles received by this journal (though the proportion published is a lower one) reflect this balance. Work based research in education poses particular challenges for the researcher and the practitioner, whether the focus is practitioner research, in which case the dilemmas can centre on potential role conflict between practitioner and researcher roles, or whether the work based research is observational – analyzing others’ professional practice, in which case the dilemmas can centre on power relations between researcher and researched, the politics of research, and ethical questions around care for participants and the degree of their involvement or non-involvement in the total research enterprise. This article reviews the prospects for work based research in post-compulsory education and introduces the articles in this special issue
Prevention of sports injuries in Sri Lanka: What do we know about injuries in our athletes?
In terms of safeguarding the health and well-being of athletes in Sri Lanka, a primary focus has always been toward the treatment of injuries after they have occurred and promoting rehabilitation back into sport. There has been little attention towards the primary prevention of injuries in Sri Lankan sports. As a developing sporting nation, the benefits of injury prevention are immense: from a public health and financial perspective, through to individual benefits for athletes’ physical, psychological and social health. Understanding the reasons behind the lack of motive towards sports injury prevention in the country, and challenges in developing and implementing injury prevention measures in the field is useful so that these reasons can be addressed and overcome. Based on recent experience in conducting injury prevention research among Sri Lankan junior cricketers, this article discusses injury prevention principles in sport and provides directions for future sport injury prevention research in Sri Lanka
UO2 CORROSION IN HIGH SURFACE-AREA-TO-VOLUME BATCH EXPERIMENTS
Unsaturated drip tests have been used to investigate the alteration of unirradiated UO{sub 2} and spent UO{sub 2} fuel in an unsaturated environment, such as may be expected in the proposed repository at Yucca Mountain. In these tests, simulated groundwater is periodically injected onto a sample at 90 C in a steel vessel. The solids react with the dripping groundwater and water condensed on surfaces to form a suite of U(VI) alteration phases. Solution chemistry is determined from leachate at the bottom of each vessel after the leachate stops interacting with the solids. A more detailed knowledge of the compositional evolution of the leachate is desirable. By providing just enough water to maintain a thin film of water on a small quantity of fuel in batch experiments, we can more closely monitor the compositional changes to the water as it reacts to form alteration phases
From mantle to critical zone: A review of large and giant sized deposits of the rare earth elements
This is the final version. Available from Elsevier via the DOI in this record.The rare earth elements are unusual when defining giant-sized ore deposits, as resources are often quoted as total rare earth oxide, but the importance of a deposit may be related to the grade for individual, or a limited group of the elements. Taking the total REE resource, only one currently known deposit (Bayan Obo) would class as giant (>1.7 Ă— 107 tonnes contained metal), but a range of others classify as large (>1.7 Ă— 106 tonnes). With the exception of unclassified resource estimates from the Olympic Dam IOCG deposit, all of these deposits are related to alkaline igneous activity - either carbonatites or agpaitic nepheline syenites. The total resource in these deposits must relate to the scale of the primary igneous source, but the grade is a complex function of igneous source, magmatic crystallisation, hydrothermal modification and supergene enrichment during weathering. Isotopic data suggest that the sources conducive to the formation of large REE deposits are developed in subcontinental lithospheric mantle, enriched in trace elements either by plume activity, or by previous subduction. The reactivation of such enriched mantle domains in relatively restricted geographical areas may have played a role in the formation of some of the largest deposits (e.g. Bayan Obo). Hydrothermal activity involving fluids from magmatic to meteoric sources may result in the redistribution of the REE and increases in grade, depending on primary mineralogy and the availability of ligands. Weathering and supergene enrichment of carbonatite has played a role in the formation of the highest grade deposits at Mount Weld (Australia) and Tomtor (Russia). For the individual REE with the current highest economic value (Nd and the HREE), the boundaries for the large and giant size classes are two orders of magnitude lower, and deposits enriched in these metals (agpaitic systems, ion absorption deposits) may have significant economic impact in the near future.Natural Environment Research CouncilUniversity of Exete
From spin to anyon notation: The XXZ Heisenberg model as a (or ) anyon chain
We discuss a relationship between certain one-dimensional quantum spin chains
and anyon chains. In particular we show how the XXZ Heisenberg chain is
realised as a (alternately ) anyon model. We find the
difference between the models lie primarily in choice of boundary condition.Comment: 13 page
The translation of sports injury prevention and safety promotion knowledge: insights from key intermediary organisations
Bounding the dimension of bipartite quantum systems
Let us consider the set of joint quantum correlations arising from
two-outcome local measurements on a bipartite quantum system. We prove that no
finite dimension is sufficient to generate all these sets. We approach the
problem in two different ways by constructing explicit examples for every
dimension d, which demonstrates that there exist bipartite correlations that
necessitate d-dimensional local quantum systems in order to generate them. We
also show that at least 10 two-outcome measurements must be carried out by the
two parties altogether so as to generate bipartite joint correlations not
achievable by two-dimensional local systems. The smallest explicit example we
found involves 11 settings.Comment: 9 pages, no figures; published versio
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