Identification of the age-period-cohort model and the extended chain ladder model

In this paper, we consider the identification problem arising in the age-period-cohort models, as well as in the extended chain ladder model. We propose a canonical parametrization based on the accelerations of the trends in the three factors. This parametrization is exactly identified. It eases interpretation, estimation and forecasting. The canonical parametrization is shown to apply for a class of index sets which have trapezoid shapes, including various Lexis diagrams and the insurance reserving triangles.

Stabilizing Traffic via Autonomous Vehicles: A Continuum Mean Field Game Approach

This paper presents scalable traffic stability analysis for both pure autonomous vehicle (AV) traffic and mixed traffic based on continuum traffic flow models. Human vehicles are modeled by a non-equilibrium traffic flow model, i.e., Aw-Rascle-Zhang (ARZ), which is unstable. AVs are modeled by the mean field game which assumes AVs are rational agents with anticipation capacities. It is shown from linear stability analysis and numerical experiments that AVs help stabilize the traffic. Further, we quantify the impact of AV's penetration rate and controller design on the traffic stability. The results may provide insights for AV manufacturers and city planners.Comment: 6 page

Scalar Induced Gravitational Waves from Finslerian Inflation and Pulsar Timing Arrays Observations

The recent data from NANOGrav provide strong evidence of the existence of the \acp{SGWB}. We investigate \acp{SIGW} from Finslerian inflation as a potential source of stochastic gravitational wave background. Small-scale ($\lesssim$1 Mpc) statistically anisotropic primordial scalar perturbations can be generated in Finslerian inflation. The second order \acp{SIGW} from Finslerian inflation are also anisotropic on small scales. After spatially averaging the small-scale anisotropic \acp{SIGW}, we obtain the large-scale isotropic \acp{SGWB}. We find that the parameters of small-scale anisotropic primordial power spectrum generated by Finslerian inflation affect the \acp{PTA} observations of large-scale isotropic gravitational wave background

Testing the Nature of the D_{sJ}^*(2317)^+ and D_{sJ}(2463)^+ States Using Radiative Transitions

The Babar and CLEO collaborations have recently observed states decaying to D_s^+\pi^0 and D_s^{*+}\pi^0 respectively and suggest the possible explanation that they are the missing P-wave c\bar{s} states with J^P=0^+ and 1^+. In this note we compare the properties of the D_{sJ}^*(2317)^+ and D_{sJ}(2463)^+ states to those expected of the c\bar{s} D_{s0}^* and D_{s1} states. We expect the D_{s0}^* and D_{s1} with the reported masses to be extremely narrow, \Gamma \sim {\cal O}(10\hbox{keV}), with large branching ratios to D^*_s\gamma for the D_{s0}^* and to D^*_s\gamma and D_s\gamma for the D_{s1}. Crucial to this interpretation of the Babar and CLEO observations is the measurement of the radiative transitions. We note that it may be possible to observe the $D_{s1}(2536)$ in radiative transitions to the $D_s^*$.Comment: Major revisions to include recent observation by CLEO of D_{sJ}(2463)^+ including change of title and additional radiative transitions included in results. Conclusions are not change

Nature of the X(6900)X(6900) in partial wave decomposition of J/ψJ/ψJ/\psi J/\psi scattering

In this letter, we perform partial wave decomposition on coupled channel scattering amplitudes, $J/\psi J/\psi$-$J/\psi \psi(2S)$-$J/\psi \psi(3770)$, to study the resonance appears in these processes. Effective Lagrangians are used to describe the interactions of four charmed vector mesons, and the scattering amplitudes are calculated up to the next-to-leading order. Partial wave projections are performed, and unitarization is implemented by Pad\'e approximation. Then we fit the amplitudes to the $J/\psi J/\psi$ invariant mass spectra measured by LHCb and determine the unknown couplings. The pole parameters of the $X(6900)$ are extracted as $M=6861.0^{+6.3}_{-8.8}$~MeV and $\Gamma=129.0^{+5.6}_{-3.4}$~MeV. Our analysis implies that its quantum number prefers to be $0^{++}$. The pole counting rule and phase shifts show that it is a normal Breit-Wigner resonance and hence should be a compact tetraquark.Comment: 6 pages, 4 figure

Проблемы медицинского обслуживания моряков в Украине

Стаття присвячена деяким проблемам медичного обслуговування моряків в Україні, в тому числі питанням професійних оглядів, які визначають придатність моряка по стану здоров‘я до роботи на суднах. Розглядаються проекти пропозицій до наказу, який готується і який буде регламентувати медичні огляди моряків.The article is devoted some problems of medical service of seafarers in Ukraine, in particular to the questions of professional examinations, determining the fitness of seafarer to be fit for work on ships. The projects of appendixes are examined to the preparing order, to regulating physical examinations of seafarers