6,365 research outputs found
New Monte Carlo method for planar Poisson-Voronoi cells
By a new Monte Carlo algorithm we evaluate the sidedness probability p_n of a
planar Poisson-Voronoi cell in the range 3 \leq n \leq 1600. The algorithm is
developed on the basis of earlier theoretical work; it exploits, in particular,
the known asymptotic behavior of p_n as n\to\infty. Our p_n values all have
between four and six significant digits. Accurate n dependent averages, second
moments, and variances are obtained for the cell area and the cell perimeter.
The numerical large n behavior of these quantities is analyzed in terms of
asymptotic power series in 1/n. Snapshots are shown of typical occurrences of
extremely rare events implicating cells of up to n=1600 sides embedded in an
ordinary Poisson-Voronoi diagram. We reveal and discuss the characteristic
features of such many-sided cells and their immediate environment. Their
relevance for observable properties is stressed.Comment: 35 pages including 10 figures and 4 table
Layering in peralkaline magmas, IlÃmaussaq Complex, S Greenland
EJH acknowledges funding from a NERC PhD studentship and the work was completed at the University of St Andrews, UK.The peralkaline to agpaitic IlÃmaussaq Complex, S. Greenland, displays spectacular macrorhythmic (> 5 m) layering via the kakortokite (agpaitic nepheline syenite), which outcrops as the lowest exposed rocks in the complex. This study applies crystal size distribution (CSD) analyses and eudialyte-group mineral chemical compositions to study the marker horizon, Unit 0, and the contact to the underlying Unit − 1. Unit 0 is the best-developed unit in the kakortokites and as such is ideal for gaining insight into processes of crystal formation and growth within the layered kakortokite. The findings are consistent with a model whereby the bulk of the black and red layers developed through in situ crystallisation at the crystal mush–magma interface, whereas the white layer developed through a range of processes operating throughout the magma chamber, including density segregation (gravitational settling and flotation). Primary textures were modified through late-stage textural coarsening via grain overgrowth. An open-system model is proposed, where varying concentrations of halogens, in combination with undercooling, controlled crystal nucleation and growth to form Unit 0. Our observations suggest that the model is applicable more widely to the layering throughout the kakortokite series and potentially other layered peralkaline/agpaitic rocks around the world.Publisher PDFPeer reviewe
The Total Economic Costs Of Finance Faculty Replacement
The purpose of this study is to estimate the total economic costs associated with filling a vacated finance faculty line. These economic costs include both explicit and opportunity costs associated with the production process. Hiring costs include explicit costs such as advertising the position and implicit costs such as the opportunity costs of faculty time spent in various search committee activities. In addition, the recent market for finance professors has included a significant mark-to-market salary component associated with replacing departed faculty with new hires. This paper utilizes survey data from recent finance faculty vacancies at AACSB International accredited schools to estimate the total hiring cost equation
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Integrated street design in high-volume junctions: The case study of London’s Oxford Circus
While traditional street design relied upon segregating vehicles and pedestrians in urban areas to ensure smooth traffic flow, urban planners and traffic engineers are gradually moving away from it. Instead, under the more modern concept of integrated street design, more space and freedom of action is provided to pedestrians, the needs of whom were previously omitted. An example space to have undergone redevelopment to a more pedestrian-oriented design is London’s Oxford Circus junction. Comparing with the results of a study pre-redevelopment, the present study aims at identifying the shift in the perceptions of the pedestrians when using the space post-implementation of the new design at Oxford Circus, but also at drawing generic conclusions on the perceptions of the pedestrians towards such schemes. A questionnaire is developed and data is collected through on-street interviews with pedestrians at Oxford Circus. The results show that integrated street design offers improved way-finding, better perceived safety and more pleasant environments for pedestrians
Ground-state phase diagram for a system of interacting, non-Abelian anyons
We study an exactly solvable model of non-Abelian anyons on a
one-dimensional lattice with a free coupling parameter in the Hamiltonian. For
certain values of the coupling parameter level crossings occur, which divide
the ground-state phase diagram into four regions. We obtain explicit
expressions for the ground-state energy in each phase, for both closed and open
chain boundary conditions. For the closed chain case we show that chiral phases
occur which are characterised by non-zero ground-state momentum.Comment: 21 pages, accepted to be published in Nucl. Phys.
The Solar Neighborhood XV: Discovery of New High Proper Motion Stars with mu >= 0.4"/yr between Declinations -47 degrees and 00 degrees
We report the discovery of 152 new high proper motion systems (mu >= 0.4"/yr)
in the southern sky (Declination = -47 degrees to 00 degrees) brighter than
UKST plate R_{59F} =16.5 via our SuperCOSMOS-RECONS (SCR) search. This paper
complements Paper XII in The Solar Neighborhood series, which covered the
region from Declination = -90 degrees to -47 degrees and discussed all 147 new
systems from the southernmost phase of the search. Among the total of 299
systems from both papers, there are 148 (71 in Paper XII, 77 in this paper) new
systems moving faster than 0.5"/yr that are additions to the classic ``LHS''
(Luyten Half Second) sample. These constitute an 8% increase in the sample of
all stellar systems with mu >= 0.5"/yr in the southern sky.
As in Paper XII, distance estimates are provided for the systems reported
here based upon a combination of photographic plate magnitudes and 2MASS
photometry, assuming all stars are on the main sequence. Two SCR systems from
the portion of the sky included in this paper are anticipated to be within 10
pc, and an additional 23 are within 25 pc. In total, the results presented in
Paper XII and here for this SCR sweep of the entire southern sky include five
new systems within 10 pc and 38 more between 10 and 25 pc. The largest number
of nearby systems have been found in the slowest proper motion bin, 0.6"/yr >
mu >= 0.4"/yr, indicating that there may be a large population of low proper
motion systems very near the Sun.Comment: 36 pages, 5 figures, accepted for publication in Astronomical Journa
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
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
Observing Spontaneous Strong Parity Violation in Heavy-Ion Collisions
We discuss the problem of observing spontaneous parity and CP violation in
collision systems. We discuss and propose observables which may be used in
heavy-ion collisions to observe such violations, as well as event-by-event
methods to analyze the data. Finally, we discuss simple monte-carlo models of
these CP violating effects which we have used to develop our techniques and
from which we derive rough estimates of sensitivities to signals which may be
seen at RHIC
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