On the phase structure of a chiral invariant Higgs-Yukawa model

In the past the construction of Higgs-Yukawa models on the lattice was blocked by the lack of a consistent definition of a chiral invariant Yukawa coupling term. Here, we consider a chiral invariant Higgs-Yukawa model based on the overlap operator, realized by the Neuberger-Dirac operator. As a first step towards a numerical examination of this model we study its phase diagram by means of an analytic 1/N-expansion, which is possible for small and for large values of the Yukawa coupling constant. In the case of strong Yukawa couplings the model effectively becomes an O(4)-symmetric non-linear sigma-model.Comment: 7 pages, 3 figures, Lattice conference 2006, corrected typo

Higgs boson mass bounds in the presence of a heavy fourth quark family

We present Higgs boson mass bounds in a lattice regularization allowing thus for non-perturbative investigations. In particular, we employ a lattice modified chiral invariant Higgs-Yukawa model using the overlap operator. We show results for the upper and lower Higgs boson mass bounds in the presence of a heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We perform infinite volume extrapolations in most cases, and examine several values of the lattice cutoff. Furthermore, we argue that the lower Higgs boson mass bound is stable with respect to the addition of higher dimensional operators to the scalar field potential. Our results have severe consequences for the phenomenology of a fourth generation of quarks if a light Higgs boson is discovered at the LHC

MOA: Massive Online Analysis, a framework for stream classification and clustering.

Massive Online Analysis (MOA) is a software environment for implementing algorithms and running experiments for online learning from evolving data streams. MOA is designed to deal with the challenging problem of scaling up the implementation of state of the art algorithms to real world dataset sizes. It contains collection of offline and online for both classification and clustering as well as tools for evaluation. In particular, for classification it implements boosting, bagging, and Hoeffding Trees, all with and without Naive Bayes classifiers at the leaves. For clustering, it implements StreamKM++, CluStream, ClusTree, Den-Stream, D-Stream and CobWeb. Researchers benefit from MOA by getting insights into workings and problems of different approaches, practitioners can easily apply and compare several algorithms to real world data set and settings. MOA supports bi-directional interaction with WEKA, the Waikato Environment for Knowledge Analysis, and is released under the GNU GPL license

Small subunit ribosomal metabarcoding reveals extraordinary trypanosomatid diversity in Brazilian bats

Background: Bats are a highly successful, globally dispersed order of mammals that occupy a wide array of ecological niches. They are also intensely parasitized and implicated in multiple viral, bacterial and parasitic zoonoses. Trypanosomes are thought to be especially abundant and diverse in bats. In this study, we used 18S ribosomal RNA metabarcoding to probe bat trypanosome diversity in unprecedented detail. Methodology/Principal Findings: Total DNA was extracted from the blood of 90 bat individuals (17 species) captured along Atlantic Forest fragments of Espírito Santo state, southeast Brazil. 18S ribosomal RNA was amplified by standard and/or nested PCR, then deep sequenced to recover and identify Operational Taxonomic Units (OTUs) for phylogenetic analysis. Blood samples from 34 bat individuals (13 species) tested positive for infection by 18S rRNA amplification. Amplicon sequences clustered to 14 OTUs, of which five were identified as Trypanosoma cruzi I, T. cruzi III/V, Trypanosoma cruzi marinkellei, Trypanosoma rangeli, and Trypanosoma dionisii, and seven were identified as novel genotypes monophyletic to basal T. cruzi clade types of the New World. Another OTU was identified as a trypanosome like those found in reptiles. Surprisingly, the remaining OTU was identified as Bodo saltans–closest non-parasitic relative of the trypanosomatid order. While three blood samples featured just one OTU (T. dionisii), all others resolved as mixed infections of up to eight OTUs. Conclusions/Significance: This study demonstrates the utility of next-generation barcoding methods to screen parasite diversity in mammalian reservoir hosts. We exposed high rates of local bat parasitism by multiple trypanosome species, some known to cause fatal human disease, others non-pathogenic, novel or yet little understood. Our results highlight bats as a long-standing nexus among host-parasite interactions of multiple niches, sustained in part by opportunistic and incidental infections of consequence to evolutionary theory as much as to public health. Author summary: Bats make up a mega-diverse, intensely parasitized order of volant mammals whose unique behavioural and physiological adaptations promote infection by a vast array of microorganisms. Trypanosomes stand out as ancient protozoan parasites of bats. As cryptic morphology, low parasitaemia and selective growth in culture have recurrently biased survey, we used 18S ribosomal RNA metabarcoding to resolve bat trypanosomatid diversity in Atlantic Forest fragments of southeast Brazil. Next to several unknown species, our deep sequence-based detection and assignment protocol recognized multiple known human-pathogenic trypanosomes, another linked to reptile hosts as well as a non-parasitic kinetoplastid in the blood of various phyllostomid bats. The striking permissivity exposed here, in a region where bat trypanosomes recently featured in a fatal case of Chagas disease, compels further research on bats’ role in the dispersal and spill-over of various microorganisms among humans and wildlife

Crystalline phases at finite winding densities in a quantum link ladder

Condensed matter physics of gauge theories coupled to fermions can exhibit a rich phase structure, but are nevertheless very difficult to study in Monte Carlo simulations when they are afflicted by a sign problem. As an alternate approach, we use tensor network methods to explore the finite density physics of Abelian gauge theories without dynamical matter. As a concrete example, we consider the U(1) gauge invariant quantum link ladder with spin-1/2 gauge fields in an external electric field which cause the winding electric fluxes to condense in the ground state. We demonstrate how the electric flux tubes arrange themselves in the bulk giving rise to crystalline patterns, whose period can be controlled by tuning the external field. We propose observables to detect the transitions in ground state properties not only in numerical experiments, but also in future cold-atom realizations. A systematic procedure for reaching the thermodynamic limit, as well as extending the studies from ladders to extended geometries is outlined.Comment: 8 pages, 7 figure

The phase structure of a chirally invariant lattice Higgs-Yukawa model for small and for large values of the Yukawa coupling constant

We consider a chirally invariant lattice Higgs-Yukawa model based on the Neuberger overlap operator. As a first step towards the eventual determination of Higgs mass bounds we study the phase diagram of the model analytically in the large Nf-limit. We present an expression for the effective potential at tree-level in the regime of small Yukawa and quartic coupling constants and determine the order of the phase transitions. In the case of strong Yukawa couplings the model effectively becomes an O(4)-symmetric non-linear sigma-model for all values of the quartic coupling constant. This leads to the existence of a symmetric phase also in the regime of large values of the Yukawa coupling constant. On finite and small lattices, however, strong finite volume effects prevent the expectation value of the Higgs field from vanishing thus obscuring the existence of the symmetric phase at strong Yukawa couplings.Comment: 21 pages, 6 figures, added reference

Institutionelle Grenzen erweitern - der Life-Space von Bewohnern in der stationären Altenpflege und dessen Modifikation mittels eines Trainingsprogramms zur Steigerung der körperlichen Aktivität

Diese publikationsbasierte Dissertation widmet sich der Beschreibung des Life-Space von Bewohnern der stationären Altenpflege sowie der Entwicklung und Evaluation eines individualisierten, mehrdimensionalen Interventionsansatzes zur Life-Space Modifikation mit Schwerpunkt auf körperlichem Training. Manuskript I ist eine systematische Übersichtsarbeit (systematisches Review) zu randomisierten, kontrollierten Interventionsstudien (RCTs) im Pflegeheim und deren Effekte auf körperliche Aktivität von Pflegeheimbewohnern. Lediglich in acht RCTs wurde körperliche Aktivität erfasst, nur eine Studie betrachtete diese als primären Endpunkt. Interventionen, welche zusätzlich zu körperlichem Training auch psycho¬soziale und Verhaltensaspekte berücksichtigten und Pflegeheimpersonal miteinbe¬zogen, zeigten die vielversprechendsten Effekte. Die starke Heterogeni¬tät der Interventionsprogramme und meist unzureichende psychometrische Qualität der Erhe¬bungsmethoden schränkte die Interpretierbarkeit der Ergebnisse jedoch ein. Basierend auf den Erkenntnissen aus dem systematischen Review wurden die Interventionsbausteine und Erhebungsmethoden zur Erfassung des Bewegungs-verhaltens in Form von Life-Space Nutzung und körperlicher Aktivität konzipiert. Das entsprechende Studienprotokoll stellt Manuskript II dar. In Manuskript III wird der Life-Space von Pflegeheimbewohnern erstmals unter Einsatz eines kabellosen Sensornetzwerks technisch sowie räumlich und zeitlich aufgelöst beschrieben. Der Life-Space der Bewohner (n = 65) war nahezu gänzlich auf das eigene Zimmer (36,6% des Tages wurden dort verbracht) und den das Zimmer umgebenden Wohnbereich (53,8%) beschränkt. Mittels linearer Regression wurde gezeigt, dass sozidodemografische Faktoren, motorische Leistung, kognitiver Status und psychosoziale Faktoren signifikant mit Life-Space-Parametern assoziiert sind. Die Hauptdeterminante der Life-Space-Nutzung stellte allerdings die institutio-nelle Essensroutine dar, die sowohl den Aufenthalt im öffent¬lichen Speiseraum als auch die Raumwechselhäufigkeit der Bewohner weitestgehend bestimmte. In Manuskript IV werden positive Effekte der Intervention auf erfasste Life-Space-Parameter mittels generalized linear mixed models (GLMMs) analysiert und belegt (n = 143). Diese Analysestrategie toleriert dem Studienkollektiv entsprechend erwart-baren Datenausfall und die Nicht-Normalverteilung der Ergebnisvariablen. Die Para¬meter waren ein im Rahmen der Arbeit entwickelter Life-Space Summenscore, welcher die „durchschnittliche“ Zone (Zone 1 = Privatzimmer; Zone 2 = Wohn-bereich; Zone 3 = außerhalb des Wohnbereichs; Zone 4 = außerhalb des Gebäudes) beschreibt, in welcher sich ein Bewohner über den Tag aufhält (LSSc); die am weitesten vom jeweiligen Privatzimmer entfernte, vom Bewohner aufgesuchte Zone (MaxZ) als Maß für die absolute Aus¬dehnung des individuellen Life-Space; die Zeit, die ein Bewohner außerhalb des eigenen Zimmers verbringt (TAFR) als Maß für das Potenzial, an sozialen Inter¬aktionen teilzuhaben. Es zeigten sich signifikante Gruppenunterschiede in LSSc (β = .13, p = .003), TAFR (β = .28, p = .015) und MaxZ (β = .29, p = .003) zwischen Prä- und Posttest in der Interven-tions¬gruppe (n = 78) verglichen mit der Kontrollgruppe (n = 65). Ein signifi¬kan¬ter Effekt blieb zum Follow-Up nach drei Monaten für den Parameter MaxZ bestehen (β = .39, p = .012). Manuskript V ist ein praxisorientiertes Handbuch, dass der Forderung einer breiten Dissemination und freien Verfügbarkeit des Programms nachkommen sowie eine praktische Implementierung des Interventionsprogramms seitens interessierter End-nutzer ermöglichen soll. Es beinhaltet Leitlinien für die Durchführung wissenschaft-licher Studien im Pflegeheimsetting, theoretischen und methodisch-didaktischen Hintergrund zu den Interventionsinhalten aus LTCMo, ein Assessmenttool zur Zuweisung von Teilnehmern zu geeigneten Trainingskomponenten und bebilderte Beschreibungen zahlreicher im Projekt eingesetzter Übungen. Insgesamt belegen die Studienergebnisse einen sehr eingeschränkten Life-Space von Pflegeheimbewohnern, der jedoch trotz des engen institutionel¬len Rahmens durch den mehrdimensionalen Interventionsansatz mit Schwer¬punkt auf individual-isiertem körperlichen Training positiv verändert werden konnte. Dies gilt nahezu für das ganze Bewohnerspektrum der untersuchten Pflegeheime, ungeachtet schwe¬rer kogni¬tiver und motorisch-funktioneller Einschränkungen. Der Nachweis des Poten-zials des Programms für eine nachhaltige Implementierung in Institutionen wurde durch die Studienergebnisse sowie die Tatsache, dass das Programm in beiden Studien¬heimen unabhängig fortgeführt wurde, erbracht. Die bisherige, auf frage-bogenbasierten Erhebungsmethoden aufbauende Evidenz auf diesem Gebiet wurde mit der vorliegenden Arbeit durch neuartige, sensor-basierte Daten ergänzt. Während der Zusam¬men¬hang von Life-Space mit soziodemografischen, motorisch-funktio¬nellen, kognitiven und psycho¬sozialen Faktoren nachgewiesen wurde, stellt der Zu¬sammenhang mit weiteren bedeutsamen Faktoren wie sozialer Teilhabe und Lebens¬qualität eine hochrelevante Fragestellung für zukünftige Forschungsvorhaben dar

Characterisation of friction behaviour of intact soft solid foods and food boli

Methodologies to quantify friction forces between soft solid foods or food boli and (model) oral surfaces are desired to better understand how changes in food properties during oral processing affect sensory perception. In this short communication, friction forces (FF) occurring between polydimethylsiloxane (PDMS) surfaces and intact soft solid foods/boli were quantified. As models for intact foods, we used gelatine gels varying in composition and particle size, and sausages were used as an example for real foods. Friction forces measured during the relative motion of intact foods against a rough PDMS surface (“oral surface”), strongly depended on the composition of the food. Friction forces were significantly lower for PDMS against emulsion-filled gels, than for PDMS against unfilled gels, likely due to the lubricating effect of released oil from the gel. Moreover, sausages, displayed significantly higher friction forces than gelatine gels when moving against the PDMS probe, presumably linked to differences in the surface of the foods. The friction forces observed for the PDMS probe moving against food boli were dependent on particle size and saliva quantity; boli with larger particle sizes showed significantly lower friction forces, whereas the addition of saliva to food boli first increased friction forces, but with increasing amount decreased the friction forces significantly. We conclude that the presented methodology is able to quantify the friction behaviour of intact soft solid foods and boli directly, taking into account (i) the effect of composition and added fillers, (ii) serum or oil release and (iii) bolus particle size.</p

Application of multivariate analysis in the processing of medical data

Medical data frequently represent multidimensional datasets as investigated factors and clinical and laboratory parameters coverage is huge. This research area is very important in terms of practical applications. We were given monthly lipid metabolism and hormonal status data of children (including children suffering from obesity) of Siberian region during a year. In this article some research results appear

Upward and Orthogonal Planarity are W[1]-hard Parameterized by Treewidth

Upward planarity testing and Rectilinear planarity testing are central problems in graph drawing. It is known that they are both NP-complete, but XP when parameterized by treewidth. In this paper we show that these two problems are W[1]-hard parameterized by treewidth, which answers open problems posed in two earlier papers. The key step in our proof is an analysis of the All-or-Nothing Flow problem, a generalization of which was used as an intermediate step in the NP-completeness proof for both planarity testing problems. We prove that the flow problem is W[1]-hard parameterized by treewidth on planar graphs, and that the existing chain of reductions to the planarity testing problems can be adapted without blowing up the treewidth. Our reductions also show that the known $n^{O(tw)}$-time algorithms cannot be improved to run in time $n^{o(tw)}$ unless ETH fails.Comment: Appears in the Proceedings of the 31st International Symposium on Graph Drawing and Network Visualization (GD 2023