Lyapunov exponents in Minkowskian U(1) gauge theory

U(1) gauge fields are decomposed into a monopole and photon part across the phase transition from the confinement to the Coulomb phase. We analyze the leading Lyapunov exponents of such gauge field configurations on the lattice which are initialized by quantum Monte Carlo simulations. We observe that the monopole field carries the same Lyapunov exponent as the original U(1) field. Evidence is found that monopole fields stay chaotic in the continuum whereas the photon fields are regular.Comment: Lattice2002(topology), 3 pages, 4 figure

Adalbert Ihle. Missionæren der tippede magtbalancen i Det Danske Missionsselskab

Hen over foråret og sommeren 1889 oprulledes der en sag, som har fået navnet “ihlesagen”, og som rystede DMS i sådan grad, at det fremkaldte såvel et ledelsesskifte som et systemskifte i missionsselskabet. Sagen handlede om en missionær, der havde været lidt for optimistisk i sine rapporter hjem til bestyrelsen og missionsvennerne. Da missionær Adalbert Ihle i foråret 1889 vendte hjem til Danmark efter tolv års tjeneste i Det Danske Missionsselskabs (DMS) arbejdsområde i Arcot i Sydindien, fik han at vide, at han ikke ville kunne genudsendes, da DMS’ bestyrelse ikke længere havde tillid til ham. Tilsyneladende var der tale om, at Ihle havde gjort sig skyldig i magtmisbrug, både hvad angår økonomisk forvaltning og blomstrende rapporter hjem til bestyrelsen om dåbstal, der ikke havde bund i virkeligheden. Men i virkeligheden var der snarere tale om, at der var kræfter i dansk kirkeliv, der pønsede på at overtage ledelsen af DMS og kun ventede på, at der skulle opstå en sag, som kunne bruges som løftestang til at gennemføre et systemskifte. I dette spil blev Ihle en velkommen brik. I det følgende vil vi først se på, hvorledes selve sagen opstod, og hvad den indeholdt. Derpå vil vi følge de forskellige aktørers brug af sagen, hvor man dels krævede Ihles afsked, dels at bestyrelsens formand og forretningsudvalg skulle træde tilbage for at give plads til nye folk. Herefter vil vi se på det store møde mellem DMS’ bestyrelse og repræsentanter for forskellige dele af dansk kirkeliv, som fandt sted i Fredericia i oktober 1889, og hvor DMS fik en helt ny struktur. Ved dette møde, der var indkaldt, for at bestyrelsen skulle give en redegørelse til missionsvennerne om, hvorfor man havde afskediget Ihle, kom ihlesagen i virkeligheden til at fylde en ganske lille del af dagsordenen. På den baggrund diskuterer jeg, om Ihles afsked var berettiget eller ej. At Ihle blev brugt politisk til at forskellige aktører kunne nå deres mål, er uomtvisteligt. Men var afskedigelsen berettiget

Semi-automatic supervised classification of minerals from x-ray mapping images

This paper addresses the problem of classifying minerals common in siliciclastic and carbonate rocks. Twelve chemical elements are mapped from thin sections by energy dispersive spectroscopy (EDS) in a scanning electron microscope (SEM). Traditional multivariate statistical methods and extensions hereof are applied to perform the classification. First, training and validation sets are grown from one or a few seed points by a method that ensures spatial and spectral closeness of observations. Spectral closeness is obtained by excluding observations that have high Mahalanobis distances to the training class mean. Spatial closeness is obtained by requesting connectivity. Second, class consistency is controlled by forcing each class into 5-10 subclasses and checking the separability of these sub-classes by means of canonical discriminant analysis. Third, class separability is checked by means of the Jeffreys-Matusita distance and the posterior probability of a class mean being classified as another class. Fourth, the actual classification is carried out based on four supervised classifiers all assuming multi-normal distributions: simple quadratic, a contextual quadratic and two hierarchical quadratic classifiers. Overall weighted misclassification rates for all quadratic classifiers are very low, for both the training (0.25%-0.33%) and validation sets (0.65%-1.13%). Finally, the number of rejected observations in routine runs is checked to control the performance of the SEM image acquisition and the classification. Although the contextual classifier performs (marginally) best on the validation set, the simple quadratic classifier is chosen in routine classifications because of the lower processing time required. This method is presently used as a routine petrographical analysis method at Norsk Hydro Research Centre. 1

Exploring protocol bias in airway microbiome studies: one versus two PCR steps and 16S rRNA gene region V3 V4 versus V4

Background Studies on the airway microbiome have been performed using a wide range of laboratory protocols for high-throughput sequencing of the bacterial 16S ribosomal RNA (16S rRNA) gene. We sought to determine the impact of number of polymerase chain reaction (PCR) steps (1- or 2- steps) and choice of target marker gene region (V3 V4 and V4) on the presentation of the upper and lower airway microbiome. Our analyses included lllumina MiSeq sequencing following three setups: Setup 1 (2-step PCR; V3 V4 region), Setup 2 (2-step PCR; V4 region), Setup 3 (1-step PCR; V4 region). Samples included oral wash, protected specimen brushes and protected bronchoalveolar lavage (healthy and obstructive lung disease), and negative controls. Results The number of sequences and amplicon sequence variants (ASV) decreased in order setup1 > setup2 > setup3. This trend appeared to be associated with an increased taxonomic resolution when sequencing the V3 V4 region (setup 1) and an increased number of small ASVs in setups 1 and 2. The latter was considered a result of contamination in the two-step PCR protocols as well as sequencing across multiple runs (setup 1). Although genera Streptococcus, Prevotella, Veillonella and Rothia dominated, differences in relative abundance were observed across all setups. Analyses of beta-diversity revealed that while oral wash samples (high biomass) clustered together regardless of number of PCR steps, samples from the lungs (low biomass) separated. The removal of contaminants identified using the Decontam package in R, did not resolve differences in results between sequencing setups. Conclusions Differences in number of PCR steps will have an impact of final bacterial community descriptions, and more so for samples of low bacterial load. Our findings could not be explained by differences in contamination levels alone, and more research is needed to understand how variations in PCR-setups and reagents may be contributing to the observed protocol bias.publishedVersio

Decoherence-Free Quantum Information Processing with Four-Photon Entangled States

Decoherence-free states protect quantum information from collective noise, the predominant cause of decoherence in current implementations of quantum communication and computation. Here we demonstrate that spontaneous parametric down-conversion can be used to generate four-photon states which enable the encoding of one qubit in a decoherence-free subspace. The immunity against noise is verified by quantum state tomography of the encoded qubit. We show that particular states of the encoded qubit can be distinguished by local measurements on the four photons only.Comment: 4 pages, 4 eps figures, revtex

Shift work and use of psychotropic medicine:A follow-up study with register linkage

OBJECTIVE: This study aimed to investigate a prospective association between shift work and use of psychotropic medicine. METHODS: Survey data from random samples of the general working population of Denmark (N=19 259) were linked to data from national registers. Poisson regression was used for analyses of prospective associations between shift work and redeemed prescriptions of psychotropic medicine. Prevalent cases were excluded at baseline. In secondary analyses, we tested differential effects on subsets of psychotropic medicine and, cross-sectionally, we studied correspondence between estimates based on psychotropic medicine and self-reported mental health. According to the protocol we interpret results from the secondary analyses following the principles for nested hypothesis testing, if the primary analyses reject the null-hypothesis, and otherwise we regard it as hypothesis generating exploratory analyses. RESULTS: In the primary analysis, the rate ratio for incidence of psychotropic medicine among shift workers was 1.09 (95% confidence interval 0.99–1.21). Results from the secondary analyses suggested increased incidence of use of hypnotics, sedatives and antidepressants and decreased incidence of use of anxiolytics. Cross-sectional analysis suggested increased risk for use of psychotropic medicine (all kinds), but not for poor self-rated mental health. CONCLUSIONS: Results did not support that working in shifts to the extent that is currently practiced in Denmark is associated with an increased incidence of overall psychotropic medicine use. Future studies should test, whether there is a differential incidence for different drugs among shift workers as suggested by the secondary analyses and how psychotropic medicine use and mental health are related

High-digestible silages allow low concentrate supply without affecting milk production or methane emissions

publishedVersio

Bypassing rRNA methylation by RsmA/Dim1during ribosome maturation in the hyperthermophilic archaeon Nanoarchaeum equitans

In all free-living organisms a late-stage checkpoint in the biogenesis of the small ribosomal subunit involves rRNA modification by an RsmA/Dim1 methyltransferase. The hyperthermophilic archaeon Nanoarchaeum equitans, whose existence is confined to the surface of a second archaeon, Ignic-occus hospitalis, lacks an RsmA/Dim1 homolog. We demonstrate here that the I. hospitalis host possesses the homolog Igni_1059, which dimethylates the N-6-positions of two invariant adenosines within helix 45 of 16S rRNA in a manner identical to other RsmA/Dim1 enzymes. However, Igni_1059 is not transferred from I. hospitalis to N. equitans across their fused cell membrane structures and the corresponding nucleotides in N. equitans 16S rRNA remain unmethylated. An alternative mechanism for ribosomal subunit maturation in N. equitans is suggested by sRNA interactions that span the redundant RsmA/Dim1 site to introduce 2'-O-ribose methylations within helices 44 and 45 of the rRNA

Mindre meddelelser.

Mindre meddelelser