First-principles analysis of spin-disorder resistivity of Fe and Ni

Spin-disorder resistivity of Fe and Ni and its temperature dependence are analyzed using noncollinear density functional calculations within the supercell method. Different models of thermal spin disorder are considered, including the mean-field approximation and the nearest-neighbor Heisenberg model. Spin-disorder resistivity is found to depend weakly on magnetic short-range order. If the local moments are kept frozen at their zero-temperature values, very good agreement with experiment is obtained for Fe, but for Ni the resistivity at elevated temperatures is significantly overestimated. Agreement with experiment for Fe is improved if the local moments are iterated to self-consistency. The overestimation of the resistivity for paramagnetic Ni is attributed to the reduction of the local moments down to 0.35 Bohr magnetons. Overall, the results suggest that low-energy spin fluctuations in Fe and Ni are better viewed as classical rotations of local moments rather than quantized spin fluctuations that would require an (S+1)/S correction.Comment: 10 pages (RevTeX), 6 eps figure

Simulation Supported Estimation of End-to-End Transmission Parameters in Non-Viral Gene Delivery

Communications, in general, involve delivery of information from a source to a sink. At nano-scale, an example of a man-made communications involving interfacing with biological systems at intra-cellular level is non-viral gene delivery. From a telecommunications engineering perspective, important end-to-end parameters of such a system are: the endto- end delay, system capacity, and packet loss rate. There are neither known methods to estimate those parameters theoretically nor they are ready available from standard measurements. The paper provides estimates for those parameters based on the simulation of non-viral gene delivery system based on the queuing theory. The simulator used has been validated through the series of in-vitro laboratory experiments

Management of metastases in regional lymph nodes in melanoma patients in 2019

For several years, the standard of management in case of melanoma metastases in regional lymph nodes was to remove an adequate node group. In 2016 and 2017, the results of two large, well-designed clinical trials with randomization and a control group were published, which changed the current management. The authors of DeCOG-STL study came to the conclusion that withdrawal from completion lymph node dissection in the case of a small melanoma metastasis in a sentinel lymph node (metastasis diameter ≤1 mm) is not associated with a worsening of the 3-years’ survival chance (both in terms of overall survival and survival time to the occurrence of distant metastases). The results of MSTL-II study were similar. Based on the results of both studies presented above, in 2018 the American Society of Clinical Oncology (ASCO) and the Society of Surgical Oncology (SSO) presented joint recommendations concerning, among others, current indications for completion lymph node dissection in SNB positive melanoma patients

Calculations of spin-disorder resistivity from first principles

Spin-disorder resistivity of Fe and Ni is studied using the noncollinear density functional theory. The Landauer conductance is averaged over random disorder configurations and fitted to Ohm's law. The distribution function is approximated by the mean-field theory. The dependence of spin-disorder resistivity on magnetization in Fe is found to be in excellent agreement with the results for the isotropic s-d model. In the fully disordered state, spin-disorder resistivity for Fe is close to experiment, while for fcc Ni it exceeds the experimental value by a factor of 2.3. This result indicates strong magnetic short-range order in Ni at the Curie temperature.Comment: 3 pages, 3 figure

Measurements of Cold Nuclear Matter Effects on J/psi in the PHENIX Experiment via Deuteron-Gold Collisions

A new calculation of R_{dAu} has been performed using the 2003 d+Au data and the higher-statistics 2005 p+p data. These nuclear modification factors are compared to calculations using nuclear-modified PDFs and a J/psi breakup cross section is extracted. These values are then used to project the cold nuclear matter effects in Au+Au collisions. Additionally, a more data-driven projection is performed.Comment: 4 pages, 6 figures, proceedings for Quark Matter 200

Nonequilibrium dynamics of mixtures of active and passive colloidal particles

We develop a mesoscopic field theory for the collective nonequilibrium dynamics of multicomponent mixtures of interacting active (i.e., motile) and passive (i.e., nonmotile) colloidal particles with isometric shape in two spatial dimensions. By a stability analysis of the field theory, we obtain equations for the spinodal that describes the onset of a motility-induced instability leading to cluster formation in such mixtures. The prediction for the spinodal is found to be in good agreement with particle-resolved computer simulations. Furthermore, we show that in active-passive mixtures the spinodal instability can be of two different types. One type is associated with a stationary bifurcation and occurs also in one-component active systems, whereas the other type is associated with a Hopf bifurcation and can occur only in active-passive mixtures. Remarkably, the Hopf bifurcation leads to moving clusters. This explains recent results from simulations of active-passive particle mixtures, where moving clusters and interfaces that are not seen in the corresponding one-component systems have been observed.Comment: 17 pages, 3 figure