1,313 research outputs found
Relaxations of GF(4)-representable matroids
We consider the GF(4)-representable matroids with a circuit-hyperplane such that the matroid obtained by relaxing the circuit-hyperplane is also GF(4)-representable. We characterize the structure of these matroids as an application of structure theorems for the classes of U2,4-fragile and {U2,5, U3,5}-fragile matroids. In addition, we characterize the forbidden submatrices in GF(4)-representations of these matroids
Influences on and patterns in total gaseous mercury (TGM) at Harwell, England
Total gaseous mercury (TGM) was monitored during 2013 at the rural monitoring site, Harwell, England using the Tekran 2537A monitoring system. Average TGM for the year was 1.45 ± 0.24 ng mâ3. This is comparable to other northern hemisphere studies, but on average 0.5 ng mâ3 higher than at its sister monitoring station at Auchencorth Moss, Scotland, but 14% lower than that found in a similar study at the same location of 1.68 ng mâ3 in 1995/6. Using wind sector analysis we show the important influence of local emissions, with our data showing that the largest influence on TGM observed is that of the adjacent Science & Innovation campus, making the site more a âsuburban backgroundâ. By using co-located measurements of black carbon and sulphur dioxide as tracers, we present an initial investigation into the impact of the closure of Didcot A coal fired power station, which ceased operating in March 2013. Further analysis using air mass back trajectories shows the long-range contribution to TGM from continental Europe, and that the lowest levels are associated with marine air masses from the west
Diffusive limit for a quantum linear Boltzmann dynamics
In this article, I study the diffusive behavior for a quantum test particle
interacting with a dilute background gas. The model I begin with is a reduced
picture for the test particle dynamics given by a quantum linear Boltzmann
equation in which the gas particle scattering is assumed to occur through a
hard-sphere interaction. The state of the particle is represented by a density
matrix that evolves according to a translation-covariant Lindblad equation. The
main result is a proof that the particle's position distribution converges to a
Gaussian under diffusive rescaling.Comment: 51 pages. I have restructured Sections 2-4 from the previous version
and corrected an error in the proof of Proposition 7.
Women, men and coronary heart disease: a review of the qualitative literature
Aim. This paper presents a review of the qualitative literature which examines the experiences of patients with coronary heart disease. The paper also assesses whether the experiences of both female and male patients are reflected in the literature and summarizes key themes.
Background. Understanding patients' experiences of their illness is important for coronary heart disease prevention and education. Qualitative methods are particularly suited to eliciting patients' detailed understandings and perceptions of illness. As much previous research has been 'gender neutral', this review pays particular attention to gender.
Methods. Published papers from 60 qualitative studies were identified for the review through searches in MEDLINE, EMBASE, CINAHL, PREMEDLINE, PsychINFO, Social Sciences Citation Index and Web of Science using keywords related to coronary heart disease.
Findings. Early qualitative studies of patients with coronary heart disease were conducted almost exclusively with men, and tended to generalize from 'male' experience to 'human' experience. By the late 1990s this pattern had changed, with the majority of studies including women and many being conducted with solely female samples. However, many studies that include both male and female coronary heart disease patients still do not have a specific gender focus. Key themes in the literature include interpreting symptoms and seeking help, belief about coronary 'candidates' and relationships with health professionals. The influence of social roles is important: many female patients have difficulties reconciling family responsibilities and medical advice, while male patients worry about being absent from work.
Conclusions. There is a need for studies that compare the experiences of men and women. There is also an urgent need for work that takes masculinity and gender roles into account when exploring the experiences of men with coronary heart disease
Self-consistent description of nuclear compressional modes
Isoscalar monopole and dipole compressional modes are computed for a variety
of closed-shell nuclei in a relativistic random-phase approximation to three
different parametrizations of the Walecka model with scalar self-interactions.
Particular emphasis is placed on the role of self-consistency which by itself,
and with little else, guarantees the decoupling of the spurious
isoscalar-dipole strength from the physical response and the conservation of
the vector current. A powerful new relation is introduced to quantify the
violation of the vector current in terms of various ground-state form-factors.
For the isoscalar-dipole mode two distinct regions are clearly identified: (i)
a high-energy component that is sensitive to the size of the nucleus and scales
with the compressibility of the model and (ii) a low-energy component that is
insensitivity to the nuclear compressibility. A fairly good description of both
compressional modes is obtained by using a ``soft'' parametrization having a
compression modulus of K=224 MeV.Comment: 28 pages and 10 figures; submitted to PR
Teleportation of a quantum state of a spatial mode with a single massive particle
Mode entanglement exists naturally between regions of space in ultra-cold
atomic gases. It has, however, been debated whether this type of entanglement
is useful for quantum protocols. This is due to a particle number
superselection rule that restricts the operations that can be performed on the
modes. In this paper, we show how to exploit the mode entanglement of just a
single particle for the teleportation of an unknown quantum state of a spatial
mode. We detail how to overcome the superselection rule to create any initial
quantum state and how to perform Bell state analysis on two of the modes. We
show that two of the four Bell states can always be reliably distinguished,
while the other two have to be grouped together due to an unsatisfied phase
matching condition. The teleportation of an unknown state of a quantum mode
thus only succeeds half of the time.Comment: 12 pages, 1 figure, this paper was presented at TQC 2010 and extends
the work of Phys. Rev. Lett. 103, 200502 (2009
The Williams Scale of Attitude toward Paganism: development and application among British Pagans
This article builds on the tradition of attitudinal measures of religiosity established by Leslie Francis and colleagues with the Francis Scale of Attitude toward Christianity (and reflected in the Sahin-Francis Scale of Attitude toward Islam, the Katz-Francis Scale of Attitude toward Judaism, and the Santosh-Francis Scale of Attitude toward Hinduism) by introducing a new measure to assess the attitudinal disposition of Pagans. A battery of items was completed by 75 members of a Pagan Summer Camp. These items were reduced to produce a 21-item scale that measured aspects of Paganism concerned with: the God/Goddess, worshipping, prayer, and coven. The scale recorded an alpha coefficient of 0.93. Construct validity of the Williams Scale of Attitude toward Paganism was demonstrated by the clear association with measures of participation in private rituals
Rethinking the Ambiguities of Abstraction in the Anthropocene
The ambiguities of abstraction were at the heart of critical approaches to the problems of modernity. Abstraction, so fundamental to the modernist episteme, was seen to have alienated humanity from itself and from its entangled relations with its environment, constituting a fundamental rift between the subject and the world. This article analyses how the critique of the modernist episteme has increasingly shifted under the auspices of the Anthropocene. Rather than seeking to overcome the ambiguities of abstraction and return the human to the world, approaches that seek to affirm the Anthropocene have emphasised that modernist thought did not take abstraction far enough. Rather than abstraction being problematic for contemporary thought, abstraction is seen to be a facet of the world in its lively, partial and contingent interaction. This article is organised in three sections. The first section introduces the problematic of abstraction in the Anthropocene, highlighting that critical theory approaches tend to see the Anthropocene within a discourse of modernist critique. The second section draws out the importance of understanding the distinct mode of contemporary affirmation, which rather than seeking to return man to the world, emphasises the impossibility of finding meaning in the world. It is this inverting of critical understandings that enables abstraction to be seen positively rather than problematically. The final section expands on this point to consider how contemporary theoretical approaches articulate the transvaluation of abstraction as the guide to contemporary modes of life
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