Portmanteau tests for linearity of Stationary Time Series

This paper considers the problem of testing for linearity of stationary time series. Portmanteau tests are discussed which are based on generalized correlations of residuals from a linear model (that is, autocorrelations and cross-correlations of different powers of the residuals). The finite-sample properties of the tests are assessed by means of Monte Carlo experiments. The tests are applied to 100 time series of stock returns

Magneto-optical studies of BaFe12O19 films grown by metallo-organic decomposition

M-type barium hexagonal ferrites BaFe12O19 (BaM) films considered for new devices that operate in the 40-70 GHz range with small or zero applied magnetic fields were characterized by magneto-optical (MO) complex polar “Kerr” effect (PKE) spectroscopy, MO magnetometry, and spectral ellipsometry (SE). The textured polycrystalline films were grown on Pt(111)/TiO2 template on Si wafer using metallo-organic decomposition technique (MOD) followed by rapid thermal annealing. In the films grown in one, two and three MOD iterations, the thickness was evaluated by SE and transmission electron microscopy. The film thickness ranged from 30 nm to 50 nm per MOD iteration. The best films display out-of-plane effective magnetic anisotropy field of 13 kOe, high perpendicular remanent magnetization and ferromagnetic resonance linewidth of 340 Oe at 60 GHz. The coercivity deduced from the MO hysteresis loops ranged between 0.25 kOe and 0.52 kOe. The SE and PKE spectra were taken at photon energies from 0.7 eV to 6.4 eV and from 1.2 eV to 4.8 eV, respectively. The PKE spectra display the structure observed on BaM single crystal natural faces normal to the c-axis. They are consistent with magnetoplumbite structure, with high degree of grain c-axis ordering, absence of foreign phases and Fe valence-exchange mechanism. Single phase nature of the films was further confirmed by grazing incidence X-ray diffraction and 57Fe nuclear magnetic resonance at 4.2 K.Web of Science561330132

Bootstrap-assisted tests of symmetry for dependent data

The paper considers the problem of testing for symmetry (about an unknown centre) of the marginal distribution of a strictly stationary and weakly dependent stochastic process. The possibility of using the autoregressive sieve bootstrap and stationary bootstrap procedures to obtain critical values and P-values for symmetry tests is explored. Bootstrap-assisted tests for symmetry are straightforward to implement and require no prior estimation of asymptotic variances. The small-sample properties of a wide variety of tests are investigated using Monte Carlo experiments. A bootstrap-assisted version of the triples test is found to have the best overall performance

Tunable Chiral Second-Order Nonlinear Optical Chromophores Based on Helquat Dications

Fourteen new dipolar cations have been synthesized, containing methoxy or tertiary amino electron donor groups attached to helquat (Hq) acceptors. These Hq derivatives have been characterized as their TfO^– salts by using various techniques including NMR and electronic absorption spectroscopies. UV–vis spectra show intense, relatively low energy absorptions with λ_(max) ≈ 400–600 nm, attributable to intramolecular charge-transfer (ICT) excitations. Single-crystal X-ray structures have been solved for two of the chromophores, one as its PF_6^– salt, revealing centrosymmetric packing arrangements (space groups Pbca and P1̅). Molecular quadratic nonlinear optical (NLO) responses have been determined directly by using hyper-Rayleigh scattering (HRS) with a 800 nm laser, and indirectly via Stark (electroabsorption) spectroscopy for the low energy absorption bands. The obtained static first hyperpolarizabilities β_0 range from moderate to large: (9–140) × 10^(–30) esu from HRS in MeCN and (44–580) × 10^(–30) esu from the Stark data in PrCN. The magnitude of β_0 increases upon either extending the π-conjugation length or replacing a methoxy with a tertiary amino electron donor substituent. Density functional theory (DFT) and time-dependent DFT calculations on selected tertiary amino chromophores confirm that the low energy absorptions have ICT character. Relatively good agreement between the simulated and experimental UV–vis absorption spectra is achieved by using the CAM-B3LYP functional with the 6-311G(d) basis set. The β_(tot) values predicted by using DFT at the same level of theory are large ((472–1443) × 10^(–30) esu in MeCN). Both the theoretical and experimental results show that para-conjugation between Hq and electron donor fragments is optimal, and enlarging the Hq unit is inconsequential with respect to the molecular quadratic NLO response

Dynamic changes in genomic and social structures in third millennium BCE central Europe

Europe’s prehistory oversaw dynamic and complex interactions of diverse societies, hitherto unexplored at detailed regional scales. Studying 271 human genomes dated ~4900 to 1600 BCE from the European heartland, Bohemia, we reveal unprecedented genetic changes and social processes. Major migrations preceded the arrival of “steppe” ancestry, and at ~2800 BCE, three genetically and culturally differentiated groups coexisted. Corded Ware appeared by 2900 BCE, were initially genetically diverse, did not derive all steppe ancestry from known Yamnaya, and assimilated females of diverse backgrounds. Both Corded Ware and Bell Beaker groups underwent dynamic changes, involving sharp reductions and complete replacements of Y-chromosomal diversity at ~2600 and ~2400 BCE, respectively, the latter accompanied by increased Neolithic-like ancestry. The Bronze Age saw new social organization emerge amid a ≥40% population turnover.Introduction Results - General sample overview - Bohemia before Corded Ware (pre-CW, before ~2800 BCE) - Corded Ware - Bell Beaker - EBA—Únětice culture Discussion Materials and methods - Processing sites for the newly reported individuals - Sampling - DNA extraction - DNA libraries and in-solution capture - Sequencing - Sex determination and authentication - Genotyping - Mitochondrial and Y chromosome haplogroups - Principal components analysis - Ancestry decomposition and admixture modeling - Y haplogroup frequency simulation

Transcriptomic profiling of host-parasite interactions in the microsporidian <i>Trachipleistophora hominis</i>

BACKGROUND: Trachipleistophora hominis was isolated from an HIV/AIDS patient and is a member of a highly successful group of obligate intracellular parasites. METHODS: Here we have investigated the evolution of the parasite and the interplay between host and parasite gene expression using transcriptomics of T. hominis-infected rabbit kidney cells. RESULTS: T. hominis has about 30 % more genes than small-genome microsporidians. Highly expressed genes include those involved in growth, replication, defence against oxidative stress, and a large fraction of uncharacterised genes. Chaperones are also highly expressed and may buffer the deleterious effects of the large number of non-synonymous mutations observed in essential T. hominis genes. Host expression suggests a general cellular shutdown upon infection, but ATP, amino sugar and nucleotide sugar production appear enhanced, potentially providing the parasite with substrates it cannot make itself. Expression divergence of duplicated genes, including transporters used to acquire host metabolites, demonstrates ongoing functional diversification during microsporidian evolution. We identified overlapping transcription at more than 100 loci in the sparse T. hominis genome, demonstrating that this feature is not caused by genome compaction. The detection of additional transposons of insect origin strongly suggests that the natural host for T. hominis is an insect. CONCLUSIONS: Our results reveal that the evolution of contemporary microsporidian genomes is highly dynamic and innovative. Moreover, highly expressed T. hominis genes of unknown function include a cohort that are shared among all microsporidians, indicating that some strongly conserved features of the biology of these enormously successful parasites remain uncharacterised. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12864-015-1989-z) contains supplementary material, which is available to authorized users

Measurement of the branching fractions of (B)over-bar -> D**l(-)(v)over-bar(l) decays in events tagged by a fully reconstructed B meson

We report a measurement of the branching fractions of D**- decays based on 417 fb-1 of data collected at the (4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. Events are selected by fully reconstructing one of the B mesons in a hadronic decay mode. A fit to the invariant mass differences m(D(*))-m(D(*)) is performed to extract the signal yields of the different D** states. We observe the D**- decay modes corresponding to the four D** states predicted by heavy quark symmetry with a significance greater than 5 standard deviations including systematic uncertainties