Optical power limiting of ultrashort hyper-Gaussian pulses in cascade three-level system

Propagation of strong femtosecond hyper-Gaussian pulses in a cascade three-level molecular system is studied by solving numerically the Maxwell–Bloch equations by the iterative predictor-corrector finite-difference time-domain method.Optical power limiting behavior induced by strong nonlinear two-photon absorption is observed for different orders of the femtosecond hyper-Gaussian pulses. Pulses of a higher order temporal profile are found to have a wider power range of optical limiting but a larger output saturation intensity. Both the output saturation value and the damage threshold of optical power limiting decrease with pulse duration increasing. The decrease of the pulse area along the pulse propagation is much slower than that obtained from the two-photon area theorem due to invalidity of the slowly varying amplitude approximation and the monochromatic field hypothesis.

Zhang Xijian, a famous Chinese medicine practitioner in China, discusses the pathogenesis characteristics of adolescent central obesity based on "qi change theory"

Obesity[1]is a group of common and ancient metabolic diseases.Central obesity is common in clinical practice.Due to the simple constitution of adolescents,their pathogenesis is simple and changeable,or there is a mixture of cold and heat,or a mixture of cold and heat,or the same disease on the surface,and the pathogenesis of traditional Chinese medicine is complex and changeable.The pathogenesis of TCM pathogenesis of adolescent central obesity is analyzed with examples to provide new theoretical ideas for the treatment of obesity by Chinese medicine.

Anomalous plasmon coupling and Fano resonance under structured light

Structured light carrying orbital angular momentum(OAM)opens up a new physical dimension for studying light–matter interactions.Despite this,the complex fields created by OAM beams still remain largely unexplored in terms of their effects on surface plasmons.This paper presents a revelation of anomalous plasmon excitations in single particles and plasmon couplings of neighboring nanorods under OAM beams,which are forbidden using non-OAM sources.The plasmon excitation of single nanoparticles is determined both by photon spin angular momentum(SAM)and OAM and influenced by the locations of the nanoparticles.Specifically,when SAM and OAM are equal in magnitude and opposite in direction,a pure plasmon excitation along light propagation direction is achieved.Two plasmon dipoles show end-to-end antibonding coupling and side-by-side bounding coupling,which are the opposite of the typical couplings.Furthermore,we observe Fano resonance with a nanorod dimer:one aligned along light propagation direction acting as the bright mode and the other aligned along the global polarization direction of light acting as the dark mode,which is the opposite of the usual plasmonic Fano resonance.By taking advantage of the unique property of the OAM source,this investigation presents a novel way to control and study surface plasmons,and the research of plasmon behavior with OAM would open new avenues for controlling electromagnetic waves and enriching the spectroscopies with more degrees of freedom.

Bayesian Regularized Regression Based on Composite Quantile Method

Recently, variable selection based on penalized regression methods has received a great deal of attention, mostly through frequentist＇s models. This paper investigates regularization regression from Bayesian perspective. Our new method extends the Bayesian Lasso regression （Park and Casella, 2008） through replacing the least square loss and Lasso penalty by composite quantile loss function and adaptive Lasso penalty, which allows different penalization parameters for different regression coefficients. Based on the Bayesian hierarchical model framework, an efficient Gibbs sampler is derived to simulate the parameters from posterior distributions. Furthermore, we study the Bayesian composite quantile regression with adaptive group Lasso penalty. The distinguishing characteristic of the newly proposed method is completely data adaptive without requiring prior knowledge of the error distribution. Extensive simulations and two real data examples are used to examine the good performance of the proposed method. All results confirm that our novel method has both robustness and high efficiency and often outperforms other approaches.

The Proportional Hazards Model for Multiple Type Recurrent Gap Times

Recurrent events data and gap times between recurrent events are frequently encountered in many clinical and observational studies,and often more than one type of recurrent events is of interest.In this paper,we consider a proportional hazards model for multiple type recurrent gap times data to assess the effect of covaxiates on the censored event processes of interest.An estimating equation approach is used to obtain the estimators of regression coefficients and baseline cumulative hazard functions.We examine asymptotic properties of the proposed estimators.Finite sample properties of these estimators are demonstrated by simulations.