Orthogonal chirp division multiplexing for coherent optical fiber communications

In this paper, we propose an orthogonal chirp division multiplexing (OCDM) technique for coherent optical communication. OCDM is the principle of orthogonally multiplexing a group of linear chirped waveforms for high-speed data communication, achieving the maximum spectral efficiency (SE) for chirp spread spectrum, in a similar way as the orthogonal frequency division multiplexing (OFDM) does for frequency division multiplexing. In the coherent optical (CO)-OCDM, Fresnel transform formulates the synthesis of the orthogonal chirps; discrete Fresnel transform (DFnT) realizes the CO-OCDM in the digital domain. As both the Fresnel and Fourier transforms are trigonometric transforms, the CO-OCDM can be easily integrated into the existing CO-OFDM systems. Analyses and numerical results are provided to investigate the transmission of CO-OCDM signals over optical fibers. Moreover, experiments of 36-Gbit/s CO-OCDM signal are carried out to validate the feasibility and confirm the analyses. It is shown that the CO-OCDM can effectively compensate the dispersion and is more resilient to fading and noise impairment than OFDM

Design verification of stress and sag for 500 kV transmission line

Transmission line stress directly affects the tower sag force structure and a safe distance from the safe operation of the transmission lines play a crucial role. Calculation method for the preparation of the design process were complied, simply enter transmission liner parameters can be automatically obtained stress and sag. According to a 500 kV transmission line tests carried out stress sag design verification, checking ground found stress design errors and were corrected to ensure the safety of the project. Calculation program can be developed for different voltage levels for line stress on cables sag design verification

An Unexpected Deamination Reaction after Hydrolysis of the Pyrimidine (6-4) Pyrimidone Photoproduct

Pyrimidine (6-4) pyrimidone photoproduct (6-4PP), a common DNA photolesion formed under solar irradiation, was indicated to hydrolyze under strong basic conditions, breaking the N3–C4 bond at the 5′-thymine. The reanalysis of this reaction revealed that the resulting water adduct may not be stable as previously proposed; it readily undergoes an esterification reaction induced by the 5-OH group at 6-4PP to form a five-membered ring, eliminating a molecule of ammonia

CEO Sensation Seeking and Financial Reporting Quality

This study investigates whether CEOs’ sensation seeking is related to their firms’ financial reporting quality. Consistent with a tendency of sensation seekers to defy ethical rules, we find that firms with sensation-seeking CEOs have lower financial reporting quality and higher likelihood of accounting fraud. More specifically, we find that firms led by sensation-seeking CEOs engage in more accrual-based and real earnings management, have higher information opacity and are more likely to have internal control deficiencies and use less conservative accounting. Firms with sensation-seeking CEOs are also more likely to engage in accounting fraud as indicated by the SEC Accounting and Auditing Enforcement Release (AAER). We further find that good corporate governance does not mitigate the adverse effects of sensation-seeking CEOs on financial reporting quality. Finally, we find a positive association between sensation-seeking CEOs and audit fees. Our results are robust to CEO change, instrument variable method and propensity score matching. In summary, our results suggest that the CEO personality trait of sensation seeking plays an important role in financial reporting quality