Thermodynamics and kinetics of boundary friction

A deterministic theory describing the behavior of an ultrathin lubricant film between two atomically-smooth solid surfaces is proposed. For the description of lubricant state the parameter of excess volume arising due to chaotization of solid medium structure in the course of melting is introduced. Thermodynamic and shear melting is described consistently. Dependences of friction force on temperature of lubricant, shear velocity of rubbing surfaces, and pressure upon surfaces are analyzed. Within the framework of a simple tribological model the stick-slip mode of friction, when the lubricant periodically melts and solidifies, is described. The obtained results are qualitatively compared with the experimental data.Comment: 14 pages, 6 figures, 33 reference

Radiative and interelectronic-interaction corrections to the hyperfine splitting in highly charged B-like ions

The ground-state hyperfine splitting values of high-Z boronlike ions are calculated. Calculation of the interelectronic-interaction contribution is based on a combination of the 1/Z perturbation theory and the large-scale configuration-interaction Dirac-Fock-Sturm method. The screened QED corrections are evaluated utilizing an effective screening potential approach. Total hyperfine splitting energies are presented for several B-like ions of particular interest: {}^{45}Sc{}^{16+}, {}^{57}Fe{}^{21+}, {}^{207}Pb{}^{77+}, and {}^{209}Bi{}^{78+}. For lead and bismuth the experimental values of the 1s hyperfine splitting are employed to improve significantly the theoretical results by reducing the uncertainty due to the nuclear effects.Comment: 12 pages, 2 figures, 3 table

QED theory of transition probabilities and line profiles in highly-charged ions

A rigorous QED theory of the spectral line profiles is applied to transition probabilities in few-electron highly charged ions. Interelectron interaction corrections are included as well as radiative corrections. Parity nonconserving (PNC) amplitudes with effective weak interactions between the electrons and nucleus are also considered. QED and interelectron interaction corrections to the PNC amplitudes are derived

Evaluation of the low-lying energy levels of two- and three-electron configurations for multi-charged ions

Accurate QED evaluations of the one- and two-photon interelectron interaction for low lying two- and three-electron configurations for ions with nuclear charge numbers $60\le Z \le 93$ are performed. The three-photon interaction is also partly taken into account. The Coulomb gauge is employed. The results are compared with available experimental data and with different calculations. A detailed investigation of the behaviour of the energy levels of the configurations $1s_{1/2}2s_{1/2} {}^1 S_0$, $1s_{1/2}2p_{1/2} {}^3 P_0$ near the crossing points Z=64 and Z=92 is carried out. The crossing points are important for the future experimental search for parity nonconserving (PNC) effects in highly charged ions

Erratum: The Carnegie Supernova Project. I. Third Photometry Data Release of Low-redshift Type Ia Supernovae and Other White Dwarf Explosions (2017, AJ, 154, 211)

GalaxiesStars and planetary system

Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network

Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism

Atomistic modelling of friction of Cu and Au nanoparticles adsorbed on graphene

We present classical molecular dynamics calculations of the behavior of copper and gold nanoparticles on a graphene sheet, sheared with a constant applied force F_a. The force F_s acting on the particle from the substrate depends on the material of the nanoparticles (Au or Cu), and exhibits a sawtooth dependency on time, which we attribute to local commensurability between the metal nanoparticle surface atomic positions with the graphene lattice. The time-averaged value of F_s (the friction force) acting on Au nanoparticles increases linearly with the contact area, having slopes close to the experimentally observable ones. A qualitative model is proposed to explain the observed results

Should euthanasia be legal? An international survey of neonatal intensive care units staff

Contains fulltext : 57784.pdf (publisher's version ) (Closed access)OBJECTIVE: To present the views of a representative sample of neonatal doctors and nurses in 10 European countries on the moral acceptability of active euthanasia and its legal regulation. DESIGN: A total of 142 neonatal intensive care units were recruited by census (in the Netherlands, Sweden, Hungary, and the Baltic countries) or random sampling (in France, Germany, Italy, Spain, and the United Kingdom); 1391 doctors and 3410 nurses completed an anonymous questionnaire (response rates 89% and 86% respectively). MAIN OUTCOME MEASURE: The staff opinion that the law in their country should be changed to allow active euthanasia "more than now". RESULTS: Active euthanasia appeared to be both acceptable and practiced in the Netherlands, France, and to a lesser extent Lithuania, and less acceptable in Sweden, Hungary, Italy, and Spain. More then half (53%) of the doctors in the Netherlands, but only a quarter (24%) in France felt that the law should be changed to allow active euthanasia "more than now". For 40% of French doctors, end of life issues should not be regulated by law. Being male, regular involvement in research, less than six years professional experience, and having ever participated in a decision of active euthanasia were positively associated with an opinion favouring relaxation of legal constraints. Having had children, religiousness, and believing in the absolute value of human life showed a negative association. Nurses were slightly more likely to consider active euthanasia acceptable in selected circumstances, and to feel that the law should be changed to allow it more than now. CONCLUSIONS: Opinions of health professionals vary widely between countries, and, even where neonatal euthanasia is already practiced, do not uniformly support its legalisation