Low-energy expansion formula for one-dimensional Fokker-Planck and Schr\"odinger equations with periodic potentials

We study the low-energy behavior of the Green function for one-dimensional Fokker-Planck and Schr\"odinger equations with periodic potentials. We derive a formula for the power series expansion of reflection coefficients in terms of the wave number, and apply it to the low-energy expansion of the Green function

Dynamic Earthquake Triggering in Southern California in High Resolution: Intensity, Time Decay, and Regional Variability

遠地地震によって誘発される地震活動の特徴を解明 --地震ビッグデータ解析を通じて--. 京都大学プレスリリース. 2021-05-06.Earthquake triggering by seismic waves has been recognized as a phenomenon for nearly 30 years. However, our ability to study dynamic triggering has been limited by our ability to capture the triggering stresses accurately and record the resultant earthquakes. Here we use full waveforms from a dense seismic network and a modern, high‐resolution seismic catalog to measure triggering in Southern California from 2008 to 2017 based on interevent time ratios. We find that the fractional seismicity rate change, which we term triggering intensity or triggerability, as a function of peak strain change for the period of ∼20 s due to distant earthquakes is monotonically increasing and compatible with earlier measurements made with a disjoint data set from 1984 to 2008. A triggering strain of 1 microstrain is equivalent to the local productivity generated by an M1.8 earthquakes. This result implies that a prediction of seismicity rate changes can be made based on recorded ground shaking using the same formalism as currently used for aftershock prediction. For a teleseismic event, this small level of triggering occurs throughout the region and thus aggregates to a regional effect. We find that the triggering rate decays after the triggerer follows an Omori‐Utsu law, but at a much slower rate than a typical aftershock sequence. The slow decay rate suggests that an ancillary process such as creep or fluid flow must be part of dynamic triggering. The prevalence of triggering in areas of creep or fluid involvement reinforces this inference. A triggering cascade of secondary earthquakes is insufficient to explain the data

Putative contributions of circadian clock and sleep in the context of SARS-CoV-2 infection

Copyright © ERS 2020. This version is distributed under the terms of the Creative Commons Attribution Non-Commercial Licence 4.0Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the aetiological agent of the pandemic coronavirus disease 2019 (COVID-19), is a newly found member of the Coronaviridae family, and is closely related to, albeit with important differences from, SARS-CoV. It enters human cells through the binding of surface spike (S) glycoprotein with angiotensin-converting enzyme 2 (ACE2). The distal S1 subunit of the S protein is responsible for receptor binding, while the transmembrane S2 subunit mediates fusion between the viral envelope and the target cell membrane following proteolytic cleavage by specific cellular enzymes such as transmembrane serine protease 2 for S protein priming. As it is likely that expression levels of ACE2 affect the efficiency of virus attachment and entry, as well as disease severity, and the interactions between viral S protein and ACE2 may directly cause lung injury, ACE2 may be a potential target of therapeutic and preventative interventions.info:eu-repo/semantics/publishedVersio

Mapping of mutation-sensitive sites in protein-like chains

In this work we have studied, with the help of a simple on-lattice model, the distribution pattern of sites sensitive to point mutations ('hot' sites) in protein-like chains. It has been found that this pattern depends on the regularity of the matrix that rules the interaction between different kinds of residues. If the interaction matrix is dominated by the hydrophobic effect (Miyazawa Jernigan like matrix), this distribution is very simple - all the 'hot' sites can be found at the positions with maximum number of closest nearest neighbors (bulk). If random or nonlinear corrections are added to such an interaction matrix the distribution pattern changes. The rising of collective effects allows the 'hot' sites to be found in places with smaller number of nearest neighbors (surface) while the general trend of the 'hot' sites to fall into a bulk part of a conformation still holds.Comment: 15 pages, 6 figure

Origin of Native Driving Force in Protein Folding

We derive an expression with four adjustable parameters that reproduces well the 20x20 Miyazawa-Jernigan potential matrix extracted from known protein structures. The numerical values of the parameters can be approximately computed from the surface tension of water, water-screened dipole interactions between residues and water and among residues, and average exposures of residues in folded proteins.Comment: LaTeX file, Postscript file; 4 pages, 1 figure (mij.eps), 2 table

An Analytical Approach to the Protein Designability Problem

We present an analytical method for determining the designability of protein structures. We apply our method to the case of two-dimensional lattice structures, and give a systematic solution for the spectrum of any structure. Using this spectrum, the designability of a structure can be estimated. We outline a heirarchy of structures, from most to least designable, and show that this heirarchy depends on the potential that is used.Comment: 16 pages 4 figure

Static response of Fermi liquids with tensor interactions

We use Landau's theory of a normal Fermi liquid to derive expressions for the static response of a system with a general tensor interaction that conserves the total spin and the total angular momentum of the quasiparticle-quasihole pair. The magnetic susceptibility is calculated in detail, with the inclusion of the center of mass tensor and cross vector terms in addition to the exchange tensor one. We also introduce a new parametrization of the tensor Landau parameters which significantly reduces the importance of high angular harmonic contributions. For nuclear matter and neutron matter we find that the two most important effects of the tensor interaction are to give a contribution from multipair states and to renormalize the magnetic moments. Response to a weak probe may be calculated using similar methods, replacing the magnetic moments with the matrix elements of the weak charges

Effect of anticomplement agent K-76 COOH in hamster-to-rat and guinea pig- to-rat xenotransplantation

In normal rats, the xenobiotic K76 inhibited the C5 and probably the C2 and C3 steps of complement and effectively depressed classical complement pathway activity, alternative complement pathway activity, and the C3 complement component during and well beyond the drug's 3-hr half-life. It was tested alone and with intramuscular tacrolimus (TAC) and/or intragastric cyclophosphamide (CP) in rat recipients of heterotopic hearts from guinea pig (discordant) and hamster (concordant) donors. Single prevascularization doses of 100 and 200 mg/kg increased the median survival time of guinea pig hearts from 0.17 hr in untreated controls to 1.7 hr and 10.2 hr, respectively; with repeated injections of the 200-mg dose every 9-12 hr, graft survival time was increased to 18.1 hr. Pretreatment of guinea pig heart recipients for 10 days with TAC and CP, with or without perioperative splenectomy or infusion of donor bone marrow, further increased median graft survival time to 24 hr. Among the guinea pig recipients, the majority of treated animals died with a beating heart from respiratory failure that was ascribed to anaphylatoxins. Hamster heart survival also was increased with monotherapy using 200 mg/kg b.i.d.i.v. K76 (limited by protocol to 6 days), but only from 3 to 4 days. Survival was prolonged to 7 days with the addition to K76 of intragastric CP at 5 mg/kg per day begun 1 day before operation (to a limit of 9 days); it was prolonged to 4.5 days with the addition of intramuscular TAC at 2 mg/kg per day beginning on the day of transplantation and continued indefinitely. In contrast to the limited efficacy of the single drugs, or any two drugs in combination, the three drugs together (K76, CP, and TAC) in the same dose schedules increased median graft survival time to 61 days. Antihamster antibodies rapidly increased during the first 5 days after transplantation, and plateaued at an abnormal level in animals with long graft survival times without immediate humoral rejection. However, rejection could not be reliably prevented, and was present even in most of the xenografts recovered from most of the animals dying (usually from infection) with a beating heart. Thus, although effective complement inhibition with K76 was achieved in both guinea pig- and hamster-to-rat heart transplant models, the results suggest that effective interruption of the complement cascade will have a limited role, if any, in the induction of xenograft acceptance