2,845 research outputs found
Multidimensional CooleyâTukey Algorithms Revisited
AbstractThe representation theory of Abelian groups is used to obtain an algebraic divide-and-conquer algorithm for computing the finite Fourier transform. The algorithm computes the Fourier transform of a finite Abelian group in terms of the Fourier transforms of an arbitrary subgroup and its quotient. From this algebraic algorithm a procedure is derived for obtaining concrete factorizations of the Fourier transform matrix in terms of smaller Fourier transform matrices, diagonal multiplications, and permutations. For cyclic groups this gives as special cases the CooleyâTukey and GoodâThomas algorithms. For groups with several generators, the procedure gives a variety of multidimensional CooleyâTukey type algorithms. This method of designing multidimensional fast Fourier transform algorithms gives different data flow patterns from the standard ârowâcolumnâ approaches. We present some experimental evidence that suggests that in hierarchical memory environments these data flows are more efficient
The UN local communities and Indigenous peoples' platform: A traditional ecological knowledge-based evaluation
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium,
provided the original work is properly cited.
© 2019 The Authors. WIREs Climate Change published by Wiley Periodicals, Inc.This review evaluates the potential of the proposed local communities and Indigenous peoplesâ platform to effectively engage traditional ecological knowledge (TEK) for climate policy. Specifically, we assess the platform's potential to enable greater representation and participation of Indigenous peoples (IPs) within the United Nations Framework Convention on Climate Change (UNFCCC). An analytical
framework based on the extensive TEK and environmental management literature is developed, with a set of criteria identified against which to evaluate the platform. We find that although the process of designing the platform appears to be inclusive of Indigenous views, the structure itself does not recognize the roles that unequal power relations and colonialism play in marginalizing IPs. Limited attention
is paid to the institutional barriers within the UNFCCC and the drawbacks of pursuing knowledge âintegrationâ as an end in itself. Based on this, recommendations for improving the platform structure are put forward including using a rights based framing, giving greater decision-making power to IPs, and developing mechanisms to ensure the holistic integrity of TEK and build the overall resilience of climate mitigation and adaptation systems.Ye
Thermodynamics of the spin-flop transition in a quantum XYZ chain
A special limit of an antiferromagnetic XYZ chain was recently shown to
exhibit interesting bulk as well as surface spin-flop transitions at T=0. Here
we provide a complete calculation of the thermodynamics of the bulk transition
using a transfer-matrix-renormalization-group (TMRG) method that addresses
directly the thermodynamic limit of quantum spin chains. We also shed some
light on certain spinwave anomalies at low temperature predicted earlier by
Johnson and Bonner.Comment: 4 pages, 6 Postscript figure
2015 researcher's mini-symposium
Postgraduate researchers from the Faculties of Science, Engineering, Medicine & Surgery and Health Sciences gathered for a forum to present their research interests. The symposium was held in the afternoon of 30
January 2015 in the Engineering Lecture Theatre.
The symposium promoted multi-disciplinary networking between various university faculties. Participants
were invited based on research topic diversity and
gender balance.peer-reviewe
Panton-Valentine leukocidin associated staphylococcal disease: a cross-sectional study at a London hospital, England
AbstractRecently, there has been international concern at the rapid emergence of highly pathogenic strains of Staphylococcus aureus associated with a toxin called PantonâValentine leukocidin (PVL). In the UK, these strains are considered to be rare and mainly severe. We estimate the proportion of staphylococcal infections that are caused by strains containing the PVL genes, and describe risk factors for these infections. Three hundred and ninety consecutive S. aureus clinical isolates, submitted for routine diagnostic purposes were screened for PVL genes. Risk factors for infection were identified from the patient medical record. 9.7% (95% CI 7.0â13.1%) of clinical isolates and 20.8% of skin and soft tissue specimens contained the genes for PVL. Methicillin-resistant S. aureus with PVL was rare (0.8% of all isolates) but PVL with methicillin-sensitive S. aureus was common (9.0% of all specimens). PVL infection was more frequent in males (OR 3.0, 95% CI 1.3â7.0), and in young adults aged 20â39 years (OR 3.7, 95% CI 1.3â10.4). Over half of PVL positive S. aureus infections originated in patients based in the community. Community-onset PVL-associated disease is common in the UK and mainly causes skin and soft tissue infections that do not require admission to hospital. Consideration should be given to current infection control strategy, which advocates household contact screening and decolonization on the assumption that PVL-associated disease is rare
The 1994â2001 eruptive period at Rabaul, Papua New Guinea: Petrological and geochemical evidence for basalt injections into a shallow dacite magma reservoir, and significant SO 2 flux
The eruptions that began at Rabaul Caldera on 19 September 1994 had two focal points, the vents Tavurvur and Vulcan, located 6 km apart on opposing sides of the caldera. Vulcan eruptives define a tight cluster of dacite compositions, whereas Tavurvur eruptives span an array from equivalent dacite compositions to mafic andesites. The eruption of geochemically and mineralogically identical dacites from both vents indicates sourcing from the same magma reservoir. This, together with previously reported HâO-COâ volatile contents of dacite melt inclusions, a caldera-wide seismic low-velocity zone, and a seismically active caldera ring fault structure are consistent with the presence at 3â6 km depth of an extensive, tabular dacitic magma body having volume of about 15â150 kmÂł. The Tavurvur andesites form a linear compositional array and have strongly bimodal phenocryst assemblages that reflect dacite hybridisation with a mafic basalt. The moderately large volume SOâ flux documented in the Tavurvur volcanic plume (and negligible SOâ flux in the Vulcan plume) combined with high dissolved S contents of basaltic melt inclusions trapped in olivine of Tavurvur eruptives, indicate that the amount of degassed basaltic magma was ~ 0.1 kmÂł and suggest that the injection of this magma was confined to the Tavurvur-side (eastern to northeastern sector) of the caldera. Circumstantial evidence suggests that the eruption was triggered and evolved in response to a series of basaltic magma injections that may have commenced in 1971 and continued up until at least the start of the 1994 eruptions. The presence of zoned plagioclase phenocrysts reflecting older basalt-dacite interaction events (i.e. anorthite cores overgrown with thick andesine rims), evaluation of limited available data for the products of previous eruptions in 1878 and 1937â1943, and the episodic occurrence of major intra-caldera seismo-deformational events indicates that the shallow magma system at Rabaul Caldera is subjected to repeated mafic magma injections at intervals of several years to several decades.We thank Shane Nancarrow, formerly of Geoscience Australia, for
making many aspects of this project possible and AusAID for providing
financial support to HP to undertake research at the Australian National
University (ANU) into the 1994 and historical eruptions at Rabaul
Fitting a sum of exponentials to lattice correlation functions using a non-uniform prior
Excited states are extracted from lattice correlation functions using a
non-uniform prior on the model parameters. Models for both a single exponential
and a sum of exponentials are considered, as well as an alternate model for the
orthogonalization of the correlation functions. Results from an analysis of
torelon and glueball operators indicate the Bayesian methodology compares well
with the usual interpretation of effective mass tables produced by a
variational procedure. Applications of the methodology are discussed.Comment: 12 pages, 8 figures, 8 tables, major revision, final versio
MaxEnt power spectrum estimation using the Fourier transform for irregularly sampled data applied to a record of stellar luminosity
The principle of maximum entropy is applied to the spectral analysis of a
data signal with general variance matrix and containing gaps in the record. The
role of the entropic regularizer is to prevent one from overestimating
structure in the spectrum when faced with imperfect data. Several arguments are
presented suggesting that the arbitrary prefactor should not be introduced to
the entropy term. The introduction of that factor is not required when a
continuous Poisson distribution is used for the amplitude coefficients. We
compare the formalism for when the variance of the data is known explicitly to
that for when the variance is known only to lie in some finite range. The
result of including the entropic measure factor is to suggest a spectrum
consistent with the variance of the data which has less structure than that
given by the forward transform. An application of the methodology to example
data is demonstrated.Comment: 15 pages, 13 figures, 1 table, major revision, final version,
Accepted for publication in Astrophysics & Space Scienc
Genome-wide association study of peripheral neuropathy with D-drug-containing regimens in AIDS Clinical Trials Group protocol 384.
Stavudine (d4T) was, until recently, one of the most widely prescribed antiretroviral drugs worldwide. While there has been a major shift away from d4T use in resource-limited countries, a large number of patients have previously received (or continue to receive) d4T, and many have developed peripheral neuropathy. The identification of genetic predictors of increased risk might suggest novel therapeutic targets for such patients. In AIDS Clinical Trials Group protocol 384, antiretroviral-naĂŻve patients were randomized to d4T/didanosine (ddI)- or zidovudine/lamivudine-containing regimens. Data from d4T/ddI recipients were analyzed for genome-wide associations (approximately 1 million genetic loci) with new onset distal sensory peripheral neuropathy. Analyses involved 254 patients (49 % White, 34 % Black, 17 % Hispanic), comprising 90 peripheral neuropathy cases (32 grade 1, 35 grade 2, 23 grade 3) and 164 controls. After correcting for multiple comparisons, no polymorphism was consistently associated with neuropathy among all patients, among White, Black, and Hispanic patients analyzed separately, both in genome-wide analyses (threshold, Pâ<â5.0âĂâ10(-8)) and focused on 46 neuropathy-associated genes (threshold, Pâ<â3.5âĂâ10(-5)). In the latter analyses, the lowest P values were in KIF1A among Whites (rs10199388, Pâ=â8.4âĂâ10(-4)), in LITAF among Blacks (rs13333308, Pâ=â6.0âĂâ10(-6)), and in NEFL among Hispanics (rs17763685, Pâ=â5.6âĂâ10(-6)). Susceptibility to d4T/ddI-associated neuropathy is not explained by a single genetic variant with a marked effect
Accurate spline solutions of the Dirac equation with parity-nonconserving potential
The complete system of the B-spline solutions for the Dirac equation with the
parity-nonconserving (PNC) weak interaction effective potential is obtained.
This system can be used for the accurate evaluation of the radiative
corrections to the PNC amplitudes in the multicharged ions and neutral atoms.
The use of the scaling procedure allows for the evaluation of the PNC matrix
elements with relative accuracy .Comment: 7 page
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