Testing for Dependence in Non-Gaussian Time Series Data

This paper provides a general methodology for testing for dependence in time series data, with particular emphasis given to non-Gaussian data. A dynamic model is postulated for a continuous latent variable and the dynamic structure transferred to the non-Gaussian, possibly discrete, observations. Locally most powerful tests for various forms of dependence are derived, based on an approximate likelihood function. Invariance to the distribution adopted for the data, conditional on the latent process, is shown to hold in certain cases. The tests are applied to various financial data sets, and Monte Carlo experiments used to gauge their finite sample properties.Latent variable model; locally most powerful tests; approximate likelihood; correlation tests; stochastic volatility tests.

On azimuthal spin correlations in Higgs plus jet events at LHC

We consider the recent proposal that the distribution of the difference between azimuthal angles of the two accompanying jets in gluon-fusion induced Higgs-plus-two-jet events at LHC reflects the CP of the Higgs boson produced. We point out that the hierarchy between the Higgs boson mass and the jet transverse energy makes this observable vulnerable to logarithmically enhanced higher-order perturbative corrections. We present an evolution equation that describes the scale variation of the azimuthal angular correlation for the two jets. The emission of extra partons leads to a significant suppression of the correlation. Using the HERWIG Monte Carlo event generator, we carry out a parton-shower analysis to confirm the findings.Comment: Published version. 11 pages, 4 figures, uses JHEP3.cl

Resolution studies of cosmic-ray tracks in a TPC with GEM readout

A large volume TPC is a leading candidate for the central tracking detector at a future high energy linear collider. To improve the resolution a new readout based on micro-pattern gas detectors is being developed. Measurements of the spatial resolution of cosmic-ray tracks in a GEM TPC are presented. We find that the resolution suffers if the readout pads are too wide with respect to the charge distribution at the readout plane due to insufficient charge sharing. For narrow pads of 2 x 6 mm**2 we measure a resolution of 100 micometer at short drift distances in the absence of an axial magnetic field. The dependence of the spatial resolution as a function of drift distance allows the determination of the underlying electron statistics. Our results show that the present technique uses about half the statistical power available from the number of primary electrons. The track angle effect is observed as expected.Comment: 18 pages, 8 figures, version as published in Nucl. Inst. Met

On dynamically generated parton distribution functions and their properties

The idea of ``dynamically'' generated parton distribution functions, based on regular initial conditions at low momentum scale, is reanalyzed with particular emphasize paid to its compatibility with the factorization mechanism. Basic consequences of this approach are discussed and compared to those of the conventional approach, employing singular initial distribution functions.Comment: 15 pages, Latex, 5 figures in PS format attache

Molar morphology and occlusion of the Early Jurassic mammaliaform Erythrotherium parringtoni

Funding Information: We thank Bhart-Anjan Bhullar (Yale University, New Haven, USA) and Roger Smith (ISAM), who kindly provided the scan of Erythrotherium parringtoni, as well as Pip Brewer (Natural History Museum of Denmark, Copenhagen, Denmark), Michael Day, Farah Ahmed, Amin Garbout (all Natural History Museum, London, UK), Robert Asher and Mathew Lowe (both UMZC) for scans and access to comparative material of Morganucodon and Megazostrodon. We are also grateful to Anton Du Plessis (ISAM), Fernando Abdala (Bernard Price Institute for Palaeontological Research, Johannesburg, South Africa) and Amin Garbout (Natural History Museum, London, United Kingdom), who scanned the material used in this study. We also thank Richard Cifelli (Sam Noble Museum, Norman, USA) and David Grossnickle (University of Washington, Seattle, USA) for their kind and helpful reviews. This study was funded by grants MA 1643/15-2 and MA 1643/20-1 of the Deutsche Forschungsgemeinschaft (DFG) to TM. Publisher Copyright: Copyright © 2022 K.R.K. Jäger et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License (for details please see http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.The South African Early Jurassic morganucodontan Erythrotherium is considered by some authors to be potentially synonymous with Morganucodon, due to similar tooth morphology. However, despite their similar dental morphology, the occlusal pattern of Erythrotherium parringtoni has been described as embrasure occlusion, close to the mode of Megazostrodon rudnerae, rather than that of Morganucodon. In this study the molars of Erythrotherium were re-examined and the two alternative occlusal hypotheses were tested using the Occlusal Fingerprint Analyser (OFA). Morphological comparison of the molars of Erythrotherium parringtoni to those of Morganucodon watsoni showed similarities in cusp height and shape in lingual/buccal views, but the molars and individual cusps of Erythrotherium parringtoni are considerably narrower linguo-buccally, and more gracile. With cusps a and c close together in Erythrotherium parringtoni, cusp positioning differs from that of Morganucodon watsoni and shows similarities to the pattern in Megazostrodon rudnerae. Also, the upper molars of Erythrotherium parringtoni are aligned in a straight row and lack the angle, relative to the longitudinal axis, between the first and second upper molars that is present in Morganucodon watsoni. This results in embrasure occlusion being the only viable occlusal mode for Erythrotherium parringtoni, which was confirmed by the OFA analysis. A Morganucodon-like occlusion would allow only the main cusps a/A to contact their antagonists and thus major gaps would be present, causing considerable reduction of functionality of the dentition. Based on the morphological evidence and the differing occlusal mode, the perpetuation of Erythrotherium parringtoni as a separate genus is confirmed.Peer reviewe

Investigating hookworm genomes by comparative analysis of two Ancylostoma species

Background Hookworms, infecting over one billion people, are the mostly closely related major human parasites to the model nematode Caenorhabditis elegans. Applying genomics techniques to these species, we analyzed 3,840 and 3,149 genes from Ancylostoma caninum and A. ceylanicum. Results Transcripts originated from libraries representing infective L3 larva, stimulated L3, arrested L3, and adults. Most genes are represented in single stages including abundant transcripts like hsp-20 in infective L3 and vit-3 in adults. Over 80% of the genes have homologs in C. elegans, and nearly 30% of these were with observable RNA interference phenotypes. Homologies were identified to nematode-specific and clade V specific gene families. To study the evolution of hookworm genes, 574 A. caninum / A. ceylanicum orthologs were identified, all of which were found to be under purifying selection with distribution ratios of nonsynonymous to synonymous amino acid substitutions similar to that reported for C. elegans / C. briggsae orthologs. The phylogenetic distance between A. caninum and A. ceylanicum is almost identical to that for C. elegans / C. briggsae. Conclusion The genes discovered should substantially accelerate research toward better understanding of the parasites' basic biology as well as new therapies including vaccines and novel anthelmintics

Correlations between the mechanical loss and atomic structure of amorphous TiO2-doped Ta2O5 coatings

<p>Highly reflective dielectric mirror coatings are critical components in a range of precision optics applications including frequency combs, optical atomic clocks, precision interferometry and ring laser gyroscopes. A key limitation to the performance in these applications is thermal noise, arising from the mechanical loss of the coatings. The origins of the mechanical loss from these coatings is not well understood.</p> <p>Recent work suggests that the mechanical loss of amorphous Ta2O5 coatings can drop by as much as 40% when it is doped with TiO2. We use a combination of electron diffraction data and atomic modelling using molecular dynamics to probe the atomic structure of these coatings, and examine the correlations between changes in the atomic structure and changes in the mechanical loss of these coatings. Our results show the first correlation between changes in the mechanical loss and experimentally measured changes in the atomic structure resulting from variations in the level of TiO2 doping in TiO2-doped Ta2O5 coatings, in that increased homogeneity at the nearest-neighbour level appears to correlate with reduced mechanical loss. It is demonstrated that subtle but measurable changes in the nearest-neighbour homogeneity in an amorphous material can correlate with significant changes in macroscopic properties.</p&gt

W^+W^+ plus dijet production in the POWHEGBOX

We present an implementation of the calculation of the production of W^+W^+ plus two jets at hadron colliders, at next-to-leading order (NLO) in QCD, in the POWHEG framework, which is a method that allows the interfacing of NLO calculations to shower Monte Carlo programs. This is the first 2 -> 4 process to be described to NLO accuracy within a shower Monte Carlo framework. The implementation was built within the POWHEGBOX package. We discuss a few technical improvements that were needed in the POWHEGBOX to deal with the computer intensive nature of the NLO calculation, and argue that further improvements are possible, so that the method can match the complexity that is reached today in NLO calculations. We have interfaced our POWHEG implementation with PYTHIA and HERWIG, and present some phenomenological results, discussing similarities and differences between the pure NLO and the POWHEG+PYTHIA calculation both for inclusive and more exclusive distributions. We have made the relevant code available at the POWHEGBOX web site.Comment: 16 pages, 5 figure

Next to leading order eta production at hadron colliders

Inclusive eta production at hadron colliders is considered,based on evaluation of eta fragmentation functions at next to leading order. Absolute predictions at LHC and SSC are presented, including the ratio $\eta/\pi^0$, together with the estimate of the theoretical uncertainty, as a possible neutral background to the $H\to \gamma\gamma$ detection.Comment: 8 pages, latex, FNT/T-93/13,14 figures avilable upon reques

Higher-Order QCD Corrections to Inclusive Particle Production in p anti-p Collisions

Inclusive single-particle production cross sections have been calculated including higher-order QCD corrections. Transverse-momentum and rapidity distributions are presented and the scale dependence is studied. The results are compared with experimental data from the CERN S(p anti-p)S Collider and the Fermilab Tevatron.Comment: 28 pages, [12 uuencoded PS figures, 3 available under request]. Preprint DESY 92-13