Random RNA under tension

The Laessig-Wiese (LW) field theory for the freezing transition of random RNA secondary structures is generalized to the situation of an external force. We find a second-order phase transition at a critical applied force f = f_c. For f f_c, the extension L as a function of pulling force f scales as (f-f_c)^(1/gamma-1). The exponent gamma is calculated in an epsilon-expansion: At 1-loop order gamma = epsilon/2 = 1/2, equivalent to the disorder-free case. 2-loop results yielding gamma = 0.6 are briefly mentioned. Using a locking argument, we speculate that this result extends to the strong-disorder phase.Comment: 6 pages, 10 figures. v2: corrected typos, discussion on locking argument improve

Attenuation of the heartbeat-evoked potential in patients with atrial fibrillation

Background The heartbeat-evoked potential (HEP) is a brain response to each heartbeat, which is thought to reflect cardiac signaling to central autonomic areas and suggested to be a marker of internal body awareness (e.g., interoception). Objectives Because cardiac communication with central autonomic circuits has been shown to be impaired in patients with atrial fibrillation (AF), we hypothesized that HEPs are attenuated in these patients. Methods By simultaneous electroencephalography and electrocardiography recordings, HEP was investigated in 56 individuals with persistent AF and 56 control subjects matched for age, sex, and body mass index. Results HEP in control subjects was characterized by right frontotemporal negativity peaking around 300 to 550 ms after the R-peak, consistent with previous studies. In comparison with control subjects, HEP amplitudes were attenuated, and HEP amplitude differences remained significant when matching the samples for heart frequency, stroke volume (assessed by echocardiography), systolic blood pressure, and the amplitude of the T-wave. Effect sizes for the group differences were medium to large (Cohen’s d between 0.6 and 0.9). EEG source analysis on HEP amplitude differences pointed to a neural representation within the right insular cortex, an area known as a hub for central autonomic control. Conclusions The heartbeat-evoked potential is reduced in AF, particularly in the right insula. We speculate that the attenuated HEP in AF may be a marker of impaired heart–brain interactions. Attenuated interoception might furthermore underlie the frequent occurrence of silent AF

Ordered spectral statistics in 1D disordered supersymmetric quantum mechanics and Sinai diffusion with dilute absorbers

Some results on the ordered statistics of eigenvalues for one-dimensional random Schr\"odinger Hamiltonians are reviewed. In the case of supersymmetric quantum mechanics with disorder, the existence of low energy delocalized states induces eigenvalue correlations and makes the ordered statistics problem nontrivial. The resulting distributions are used to analyze the problem of classical diffusion in a random force field (Sinai problem) in the presence of weakly concentrated absorbers. It is shown that the slowly decaying averaged return probability of the Sinai problem, \mean{P(x,t|x,0)}\sim \ln^{-2}t, is converted into a power law decay, \mean{P(x,t|x,0)}\sim t^{-\sqrt{2\rho/g}}, where $g$ is the strength of the random force field and $\rho$ the density of absorbers.Comment: 10 pages ; LaTeX ; 4 pdf figures ; Proceedings of the meeting "Fundations and Applications of non-equilibrium statistical mechanics", Nordita, Stockholm, october 2011 ; v2: appendix added ; v3: figure 2.left adde

Time evolution of 1D gapless models from a domain-wall initial state: SLE continued?

We study the time evolution of quantum one-dimensional gapless systems evolving from initial states with a domain-wall. We generalize the path-integral imaginary time approach that together with boundary conformal field theory allows to derive the time and space dependence of general correlation functions. The latter are explicitly obtained for the Ising universality class, and the typical behavior of one- and two-point functions is derived for the general case. Possible connections with the stochastic Loewner evolution are discussed and explicit results for one-point time dependent averages are obtained for generic \kappa for boundary conditions corresponding to SLE. We use this set of results to predict the time evolution of the entanglement entropy and obtain the universal constant shift due to the presence of a domain wall in the initial state.Comment: 27 pages, 10 figure

Verbleib von Abwasserinhaltsstoffen bei bewachsenen Bodenfiltern (Pflanzenklaeranlagen) im Langzeitbetrieb

Available from TIB Hannover: RN 8422(1999,78) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The Controlled Oxidation of Hydrogen from an Explosive Mixture of Gases Using a Microstructured Reactor/Heat Exchanger and Pt/Al₂O₃ Catalyst

With advances achieved in the area of microreactor technology, new possibilities for the use of microchannel reactors in the field of heterogeneous catalysis are now attainable. By exploiting these microstructured reactors for their relatively high surface-to-volume ratio and the inherent safety due to dimensions below the quenching distance at which explosions can propagate, hazardous reaction mixtures can be handled safely. The aim of this paper is to present the results on the catalytic H2/O2 reaction obtained from an alumina-coated microstructured reactor/heat exchanger that has been impregnated with a platinum catalyst. With this reactor, explosive mixtures of gaseous hydrogen and oxygen (up to 50% by volume of H2 in O2) were safely handled and the hydrogen was completely converted to water without explosions by maintaining a heterogeneously catalyzed reaction. The homogeneous reaction was prevented through efficient removal of the heat evolved from this highly exothermic reaction with cooling gas flowing in the heat exchanger channels of the reactor. It is anticipated that the use of microstructured reactors in catalysis research will add new levels of safety and control in studying chemical systems that necessarily involve explosive mixtures of gases

Wassergefaehrdung durch undichte Kanaele - Erfassung und Bewertung. T. 2: Untersuchungen zur Erfassung und Bewertung undichter Kanaele im Hinblick auf die Gefaehrdung des Untergrundes. Bd. A Untersuchungen der Arbeitsgruppe Langen. Abschlussbericht

The project provides results from case studies on sewers carrying mainly domestic wastewater and exhibiting different types and categories of damage at the bottom, the sides and the top of the cross section of the pipe. The condition of the underlying soil was characterized by sediments of differing permeability, ranging from good to poor, with groundwater levels of less than 50 cm to as much as 500 cm below the pipe's bottom. Using indicator parameters, wastewater constituents were detected in the immediate vicinity of dage of categories 0 - 2. Infiltration is limited to a zone only a few decimetres thick, so that the occurrence of environmentally relevant concentrations is assumed to be mainly confined to the damage categories mentioned. Nevertheless, such contamination limits the multifunctional uses of excavated soil in sewer reconstruction. A recommendation for sewer repair practice is that in addition to damage necessitating immediate action, the focus in damage repair should primarily be on categories 0, 1, and 2 damage state occurring at the bottom of the pipe. Priority should be given to the repair of sewers located in areas where the subsoil consists of permeable sediments with groundwater levels of less than 100 cm, and carrying wastewater containing hazardous substances in spite of the required pretreatment. (orig.)SIGLEAvailable from TIB Hannover: QN 150(2A)+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Modellstudie ''Chlorierte Loesemittel und Umwelt''. Bd. 2 Ausfuehrliche Darstellung der Untersuchungsergebnisse zum Umgang mit leichtfluechtigen Chlorkohlenwasserstoffen in Industrie und Gewerbe und ihr Verbleib im Bereich der Emissionswege Abfall und Abwasser

TIB Hannover: RN 8908(90-001,2) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Datensammlung Bioteste - Erhebungen, Bewertung, Empfehlungen

Available from TIB Hannover: RN 8422(1998,9) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman