679 research outputs found
Predicting the long time dynamic heterogeneity in a supercooled liquid on the basis of short time heterogeneities
We report that the local Debye-Waller factor in a simulated 2D glass-forming
mixture exhibits significant spatial heterogeneities and that these short time
fluctuations provide an excellent predictor of the spatial distribution of the
long time dynamic propensities [Phys.Rev.Lett. 93, 135701 (2004)]. In contrast,
the potential energy per particle of the inherent structure does not correlate
well with the spatially distributed dynamics
The (2+1)-d U(1) Quantum Link Model Masquerading as Deconfined Criticality
The -d U(1) quantum link model is a gauge theory, amenable to quantum
simulation, with a spontaneously broken SO(2) symmetry emerging at a quantum
phase transition. Its low-energy physics is described by a -d \RP(1)
effective field theory, perturbed by a dangerously irrelevant SO(2) breaking
operator, which prevents the interpretation of the emergent pseudo-Goldstone
boson as a dual photon. At the quantum phase transition, the model mimics some
features of deconfined quantum criticality, but remains linearly confining.
Deconfinement only sets in at high temperature.Comment: 4.5 pages, 6 figure
Crystalline Confinement
We show that exotic phases arise in generalized lattice gauge theories known
as quantum link models in which classical gauge fields are replaced by quantum
operators. While these quantum models with discrete variables have a
finite-dimensional Hilbert space per link, the continuous gauge symmetry is
still exact. An efficient cluster algorithm is used to study these exotic
phases. The -d system is confining at zero temperature with a
spontaneously broken translation symmetry. A crystalline phase exhibits
confinement via multi-stranded strings between charge-anti-charge pairs. A
phase transition between two distinct confined phases is weakly first order and
has an emergent spontaneously broken approximate global symmetry. The
low-energy physics is described by a -d effective field
theory, perturbed by a dangerously irrelevant breaking operator, which
prevents the interpretation of the emergent pseudo-Goldstone boson as a dual
photon. This model is an ideal candidate to be implemented in quantum
simulators to study phenomena that are not accessible using Monte Carlo
simulations such as the real-time evolution of the confining string and the
real-time dynamics of the pseudo-Goldstone boson.Comment: Proceedings of the 31st International Symposium on Lattice Field
Theory - LATTICE 201
FGB1 and WSC3 are in planta-induced beta-glucan-binding fungal lectins with different functions
In the root endophyte Serendipita indica, several lectin-like members of the expanded multigene family of WSC proteins are transcriptionally induced in planta and are potentially involved in beta-glucan remodeling at the fungal cell wall. Using biochemical and cytological approaches we show that one of these lectins, SiWSC3 with three WSC domains, is an integral fungal cell wall component that binds to long-chain beta 1-3-glucan but has no affinity for shorter beta 1-3- or beta 1-6-linked glucose oligomers. Comparative analysis with the previously identified beta-glucan-binding lectin SiFGB1 demonstrated that whereas SiWSC3 does not require beta 1-6-linked glucose for efficient binding to branched beta 1-3-glucan, SiFGB1 does. In contrast to SiFGB1, the multivalent SiWSC3 lectin can efficiently agglutinate fungal cells and is additionally induced during fungus-fungus confrontation, suggesting different functions for these two beta-glucan-binding lectins. Our results highlight the importance of the beta-glucan cell wall component in plant-fungus interactions and the potential of beta-glucan-binding lectins as specific detection tools for fungi in vivo
Nosokomiale Harnwegsinfektionen des Erwachsenen
Zusammenfassung: Die Harnwegsinfektion ist die häufigste Infektion des Erwachsenen im Spital. Sie ist meistens mit dem Tragen von Harnwegskathetern assoziiert. Entscheidend sind daher die richtige Indikationsstellung für die Kathetereinlage, die frühzeitige Wiederentfernung des Katheters sowie die korrekte Diagnosestellung zur Vermeidung unnötiger antibiotischer Behandlungen. Die therapeutischen Überlegungen sollten die Komorbiditäten und potenzielle Behinderungen des Urinabflusses mit einschließen. In der Behandlung stehen Chinolone, Breitspektrumpenizilline und Cephalosporine der 3.Generation im Vordergrund. Bei den ökonomischen Überlegungen sollte v.a. der höhere Preis von i.v.-Antibiotika im Vergleich zu per os mit einfließe
Two-dimensional Lattice Gauge Theories with Superconducting Quantum Circuits
A quantum simulator of U(1) lattice gauge theories can be implemented with
superconducting circuits. This allows the investigation of confined and
deconfined phases in quantum link models, and of valence bond solid and spin
liquid phases in quantum dimer models. Fractionalized confining strings and the
real-time dynamics of quantum phase transitions are accessible as well. Here we
show how state-of-the-art superconducting technology allows us to simulate
these phenomena in relatively small circuit lattices. By exploiting the strong
non-linear couplings between quantized excitations emerging when
superconducting qubits are coupled, we show how to engineer gauge invariant
Hamiltonians, including ring-exchange and four-body Ising interactions. We
demonstrate that, despite decoherence and disorder effects, minimal circuit
instances allow us to investigate properties such as the dynamics of electric
flux strings, signaling confinement in gauge invariant field theories. The
experimental realization of these models in larger superconducting circuits
could address open questions beyond current computational capability.Comment: Published versio
Finite-Volume Energy Spectrum, Fractionalized Strings, and Low-Energy Effective Field Theory for the Quantum Dimer Model on the Square Lattice
We present detailed analytic calculations of finite-volume energy spectra,
mean field theory, as well as a systematic low-energy effective field theory
for the square lattice quantum dimer model. The analytic considerations explain
why a string connecting two external static charges in the confining columnar
phase fractionalizes into eight distinct strands with electric flux
. An emergent approximate spontaneously broken symmetry
gives rise to a pseudo-Goldstone boson. Remarkably, this soft phonon-like
excitation, which is massless at the Rokhsar-Kivelson (RK) point, exists far
beyond this point. The Goldstone physics is captured by a systematic low-energy
effective field theory. We determine its low-energy parameters by matching the
analytic effective field theory with exact diagonalization results and Monte
Carlo data. This confirms that the model exists in the columnar (and not in a
plaquette or mixed) phase all the way to the RK point.Comment: 35 pages, 16 figure
Vestibular and auditory deficits in Fabry disease and their response to enzyme replacement therapy
Progressive hearing (pHL) and vestibular (pVL) loss are frequent deficits in Fabry disease (FD). Recently, enzyme replacement therapy (ERT) with human α-galactosidase A has become available. Here, we investigate the association between pHL and pVL in FD and their ERT responses. Pure tone audiometry (PTA) and head impulse testing (HIT) were administered at baseline in 47 patients (25 male, 18-0 y; 22 female, 17-4 y), of whom 24 also received caloric irrigation (CI). Of the 47 patients, 38 (24 male) were tested both before and during ERT (follow- up ≤60 months). ERT consisted of agalsidase alfa infusions. At baseline, pHL was present in 88% of males and 86% of females. Over all tested frequencies (range: 0.5- kHz), pHL was significantly (two-way ANOVA: p 0.05). We conclude that pHL and pVL prevalences are similar in FD. To detect pVL, HIT is more sensitive than CI. We speculate that pHL and pVL emerge from lesions within the vestibulocochlear labyrinth, because no specific patterns of vestibulo-cochlear deficits were observed, as expected if lesions were more proximal along the inferior or superior branch of the vestibulo-cochlear nerve or labyrinthine artery. Finally, ERT stabilizes auditory and even improves vestibular functio
Emergence of SCC mec Type IV as the Most Common Type of Methicillin-Resistant Staphylococcus aureus in a University Hospital
Abstract : Background: : The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) has dramatically changed over the last decade by the emergence of community-associated MRSA (CA-MRSA). Recent studies indicate that these strains have already spread to hospitals. To evaluate if SCCmec type IV and Panton-Valentine leukocidin (PVL) are unambiguous markers of CA-MRSA, we analyzed 77 sporadic MRSA strains isolated, in our low MRSA incidence university hospital, from inpatients between 2000 and 2004. Methods: : MRSA strains were analyzed by staphylococcal cassette chromosome mmecec (SCCmec) typing, PCR for PVL genes and pulsed-field gel electrophoresis (PFGE). MRSA was classified in HA-MRSA or CA-MRSA according to Centers for Disease Control and Prevention (CDC) criteria. Antimicrobial susceptibility testing was performed using microbroth dilution method following CLSI recommendations. Results: : Among 77 sporadic single-patient strains, SCCmec types I-IV and four subtypes were identified. Type IV/IVA was most common (42.9%).The distribution of SCCmec types changed over the years. Type IV/IVA strains increased from 33.3% in 2000 to 57.9% in 2004. Type IV strains were resistant to ciprofloxacin in 81.8%, and in 9.1% to tobramycin while type IVA strains were 100% resistant to both antimicrobials. In contrast, non-type IV/IVA strains were resistant to ciprofloxacin in 86.4%, and in 75.0% to tobramycin. Only one strain was PVL positive and harbored SCCmec type III variant. By PFGE analysis, the 33 SCCmec type IV/IVA strains comprised 12 distinct genotypes. 36.4% of 11 CA-MRSA and 43.9% of 66 HA-MRSA harbored SCCmec type IV/IVA. Conclusion: : Type IV/IVA has become the most common SCCmec type in inpatients of our university hospital. The SCCmec type IV/IVA is present in both CA-MRSA and HA-MRSA limiting its use as a marker for CA-MRS
Management von echten und falschen Aneurysmen bei Hämodialyseshunts
Zusammenfassung: Hintergrund: Aneurysmen und Pseudoaneurysmen von Hämodialysezugängen treten mit einer Häufigkeit von bis zu 6% auf. Es besteht ein enger Zusammenhang mit der jeweiligen Punktionstechnik. Wegen der zunehmenden Anzahl an Dialysepatienten, wird die Zahl der Fisteloperationen auch in Zukunft steigen. Ziel: Anhand einer Literaturübersicht und gestützt auf eigene Erfahrungen soll die Behandlung von echten und falschen Aneurysmen von Hämodialyseshunts dargestellt werden. Material und Methode: Es erfolgte eine systematische Literaturrecherche in Pubmed/Medline. Folgende Suchbegriffe wurden teils in Kombination verwendet:"arteriovenous fistula”,"arteriovenous aneurysm”,"arteriovenous graft”,"haemodialysis access” und"vascular access surgery”. Ergebnisse: Eine einheitliche Definition und klare Empfehlungen zur Therapie finden wir in der Literatur nicht. Je nach Art, Größe und Lokalisation des Aneurysmas kann die Shuntfunktion gefährdet sein und es besteht Interventionsbedarf. Rupturen können sogar lebensbedrohlich werden. Schlussfolgerung: Bedingt durch stetes Punktieren, neigen AVF zur Dilatation bis hin zur Aneurysmabildung. Solche Veränderungen müssen nur dann korrigiert werden, wenn die Haut über dem Shunt gefährdet ist, wenn eine Massenblutung droht oder aufgrund einer Wandthrombosierung eine nur ungenügende Punktionsstrecke vorhanden ist. Die Implantation eines ePTFE-Interponats war bisher ein gängiges Verfahren, doch hat die Aneurysmorrhaphie vermehrt Anhänger gefunden, weil damit ohne Fremdmaterial ein Shunt funktionstüchtig gehalten werden kann. Bei Pseudoaneurysmen, meist verursacht durch punktionsbedingte, lokale Zerstörung eines PTFE-Grafts, kann ein lokaler Graftersatz erfolgen oder eine partielle Neuanlage mit Umfahrung, wenn zusätzlich ein lokaler Infekt vermutet wird. Alternativtherapien zur Chirurgie wie Stentgrafts sind aktuell noch nicht etabliert und müssen ihren Stellenwert erst noch beweise
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