91,791 research outputs found
Combinatorial classification of quantum lens spaces
We answer the question of how large the dimension of a quantum lens space
must be, compared to the primary parameter , for the isomorphism class to
depend on the secondary parameters. Since classification results in C*-algebra
theory reduces this question to one concerning a certain kind of
-equivalence of integer matrices of a special form, our approach is
entirely combinatorial and based on the counting of certain paths in the graphs
shown by Hong and Szyma\'nski to describe the quantum lens spaces.Comment: 27 pages, 2 figure
A Guide to Integrate Plant Cover Data From Two different Methods
There is a lack of consensus on how to monitor (measure) plant cover in tidal marshes. Multiple methods exist to estimate plant cover, which can confound interpretation when making comparisons across methods. Here, we provide a novel and more accurate approach, building off of traditional data transformations designed to integrate the two most common methods: Point Intercept and Ocular Cover
A definitive heat of vaporization of silicon through benchmark ab initio calculations on SiF_4
In order to resolve a significant uncertainty in the heat of vaporization of
silicon -- a fundamental parameter in gas-phase thermochemistry -- [Si(g)] has been determined from a thermochemical cycle involving
the precisely known experimental heats of formation of SiF_4(g) and F(g) and a
benchmark calculation of the total atomization energy (TAE_0) of SiF_4 using
coupled-cluster methods. Basis sets up to on Si and
on F have been employed, and extrapolations for residual basis
set incompleteness applied. The contributions of inner-shell correlation (-0.08
kcal/mol), scalar relativistic effects (-1.88 kcal/mol), atomic spin-orbit
splitting (-1.97 kcal/mol), and anharmonicity in the zero-point energy (+0.04
kcal/mol) have all been explicitly accounted for. Our benchmark TAE_0=565.89
\pm 0.22 kcal/mol leads to [Si(g)]=107.15 \pm 0.38
kcal/mol ([Si(g)]=108.19 \pm 0.38 kcal/mol): between
the JANAF/CODATA value of 106.5 \pm 1.9 kcal/mol and the revised value proposed
by Grev and Schaefer [J. Chem. Phys. 97, 8389 (1992}], 108.1 \pm 0.5 kcal/mol.
The revision will be relevant for future computational studies on heats of
formation of silicon compounds.Comment: J. Phys. Chem. A, submitted Feb 1, 199
A Design Strategy for Deadlock-Free Concurrent Systems
When building concurrent systems, it would be useful to have a collection of reusable processes
to perform standard tasks. However, without knowing certain details of the inner workings of
these components, one can never be sure that they will not cause deadlock when connected to
some particular network.
Here we describe a hierarchical method for designing complex networks of communicating
processeswhich are deadlock-free.We use this to define a safe and simple method for specifying
the communication interface to third party software components. This work is presented using
the CSP model of concurrency and the occam2.1 programming language
The Incidence of the Local Property Tax: A Re-evaluation
The article identifies the key assumptions that underlie competing theories of the incidence of the local property tax. We conclude that the"benefit view" which maintains that the property tax system is equivalent to a set of non-distortionary user changes is correct only under very restrictive assumptions. Only when communities adopt a set of exact, binding zoning requirements will a distortionary tax be transformed into a lump-sum tax. We argue that within jurisdiction heterogeneity of house and firm typeis very unlikely and that the burden of a property tax that is distortionary at the margin falls on the owners of capital.
The New View of the Property Tax: A Reformulation
The"new view" of the property tax is reformulated within the context of a model with interjurisdictional competition, endogenous local public services, individuals who are segregated into homogeneous communities according to tastes for local public services, a simple form of land use zoning, and a political or constitutional constraint on the use of head taxes by local governments. Expressions for the "profits tax" and"excise tax" effects of the property tax are derived. The effects of a "consumption distortion" away from government services due to local reluctance to tax mobile capital are also examined.
The Consequences of Polyandry for Sibship Structures, Distributions of Relationships and Relatedness, and Potential for Inbreeding in a Wild Population
We thank the Tsawout and Tseycum First Nations for access to Mandarte Island, Pirmin Nietlisbach, Lukas Keller, Greta Bocedi, Brad Duthie, and Matthew Wolak for helpful discussions, and the European Research Council, National Sciences and Engineering Research Council of Canada, and Swiss National Science Foundation for funding. Field data collected following UBC Animal Care Committee (A07-0309) and Environment Canada (Master banding permit 10596) guidelines.Peer reviewedPublisher PD
QCD Splitting/Joining Functions at Finite Temperature in the Deep LPM Regime
There exist full leading-order-in-alpha_s numerical calculations of the rates
for massless quarks and gluons to split and join in the background of a
quark-gluon plasma through hard, nearly collinear bremsstrahlung and inverse
bremsstrahlung. In the limit of partons with very high energy E, where the
physics is dominated by the Landau-Pomeranchuk-Migdal (LPM) effect, there are
also analytic leading-log calculations of these rates, where the logarithm is
ln(E/T). We extend those analytic calculations to next-to-leading-log order. We
find agreement with the full result to within roughly 20% for E(less) >~ 10 T,
where E(less) is the energy of the least energetic parton in the
splitting/joining process. We also discuss how to account for the running of
the coupling constant in the case that E/T is very large. Our results are also
applicable to isotropic non-equilibrium plasmas if the plasma does not change
significantly over the formation time associated with particle splitting.Comment: 20 pages, 6 figures. Changes from v3: Typos fixed in the subscripts
of various Casimir factor
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