Is Coherence Essential to Account for Pulsar Radio Emission?

Based on definitions, two joint-criteria, namely, the optical-thin constraint and the energy budget constraint, are proposed to judge whether the emission nature of radio pulsars is incoherent or obligatory to be coherent. We find that the widely accepted criterion, $kT_B \le \epsilon$, is not a rational criterion to describe the optical-thin condition, even for the simplest case. The energy budget constraint could be released by introducing a certain efficient radiation mechanism (e.g. the inverse Compton scattering, QL98) with emission power of a single particle as high as a critical value $P_{sing,c} to interpret high luminosities of pulsars in terms of incoherent emission mechanisms, if the optical-thin constraint could be released by certain mechanism as well. Coherence may not be an essential condition to account for pulsar radio emission

Estimation of shell radiation efficiency using a FEM-SmEdA algorithm

The radiation efficiencies of cylindrical and conical shells were investigated by using the statistical modal energy distribution analysis (SmEdA) and integrated FEM-SmEdA approaches. In cylindrical shell, three analytical algorithms were carried out, including SmEdA and two conventional approaches, i.e. the wave approach and the statistical energy analysis (SEA), and the results were compared with a former experimental one. SmEdA showed closest results with the experimental one, owing to its precise estimation of the coupling loss factors (CLF) which were further used to calculate the radiation efficiency. Furthermore, based on the analytical SmEdA, an integrated FEM-SmEdA algorithm is proposed. This hybrid method provided similar shell radiation efficiency for cylindrical shell, indicating its applicability in the analysis of complicated structures

Surgical technical experience of adult aortic coarctation concomitant with poststenotic aneurysm or dissection.

Aortic coarctation (COA) in adults combined with poststenotic aneurysm (PA) or poststenotic dissection (PD) is rare and challenging to manage. The existence of multiple factors such as kinking, comorbidities, previous surgical history, and descending aortic lesions increases the difficulty of treatment, and there are currently few clinical reports. The purpose of this study was to present our surgical experience in dealing with such patients. A retrospective study was conducted on 20 consecutive patients with COA combined with PA or PD who were treated in our center from December 2015 to April 2019. The basic principles, methods, and short- and mid-term prognosis of surgery are present carefully. This paper introduces the individualized treatment scheme as well as its advantages and disadvantages in detail. The condition of the included patients was complicated, including 12 cases of PA and 8 of PD. Although different surgical schemes were adopted, procedural success rate was 100%. There were no other surgical complications except 2 cases of anastomotic bleeding and 1 case of spinal cord injury. The results of computed tomography angiography (CTA) demonstrated that 9 cases achieved anatomical correction, 10 cases of PA or PD were eliminated or thrombosed to varying degrees, and only 1 case of PA had no obvious change. Up to the follow-up period, except for 1 patient who had a slight cerebrovascular accident and 1 who had no change in PA underwent cheatham platinum (CP) stent surgery, no other cardiovascular adverse events occurred and all patients recovered well. The optimal surgical strategy developed collaboratively by cardiac surgeons and endovascular specialists has achieved satisfactory short- and mid-term results for COA patients combined with PA or PD. Further research is still necessary, due to the limited number of cases