ABSTRACT
Acoustic deterrents are a practical strategy to mitigate the impact of underwater noise on marine mammals. However, their safety and effectiveness are still debatable. This study proposes a controllable acoustic deterrence method to protect marine mammals threatened by underwater blasting noise. The method creates strong-randomness warning signals using nonel detonators and establishes an escape time for animals protected. Combining the BELLHOP ray-based acoustic model with the marine environmental parameters and animals' auditory characteristics, we built a prediction model to establish a link between the acoustic fields and the adjustable source parameters, and provide a Risk zone and Deterrent zone for animals. The simulation and experimental results demonstrated that the root mean squared error between the simulated and measured sound pressure spectral density levels did not exceed 4.5 dB and the coefficient of determination remained at approximately 0.8, indicating that the new deterrent is an effective method with good controllable performances.
Subject(s)
Acoustics , Noise , Animals , CetaceaABSTRACT
Underwater operational turbine noise emitted by China's first offshore wind farm in the East China Sea Bridge of Shanghai was measured and analyzed in this study. Two sensors were used in the measurement: a hydrophone recording the underwater sound and an accelerometer placed in the turbine tower detecting the tower vibrations. Measurements were performed at two different types of wind turbines: a Sinovel 3 MW SL3000 turbine and a Shanghai Electric 3.6 MW W3600 turbine. The two turbines show similar tower vibration characteristics, characterized by a number of tonal components, mainly in the low-frequency domain (30-500 Hz). The peak vibration frequencies changed with the wind speed until the turbine approached its nominal power rating. Spectral analysis of the underwater acoustic data showed that the amplitude spectra had a strong correlation with the spectra of the turbine vibration intensity level, indicating that the measured underwater noise was generated by the tower mechanical vibration.
ABSTRACT
Six new polyoxygenated steroids, hippuristerones J-L (1-3), hippuristerols E-F (4, 5), and a novel gorgosteroid, 1alpha,3beta,5beta,11alpha-tetrahydroxygorgostan-6-one (6), were isolated from the gorgonian Isis hippuris. The structures of these metabolites were elucidated by extensive spectroscopic analyses and comparison of the NMR data with those of related steroids.
Subject(s)
Anthozoa/chemistry , Steroids/isolation & purification , Animals , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Steroids/chemistry , TaiwanABSTRACT
Eleven new hippuristanols (1-4, 7-9, and 11-14), along with eight known metabolites (5, 6, 10, and 15-19), have been isolated from the gorgonian coral Isis hippuris. Single-crystal X-ray diffraction analyses supported the structure elucidation of known steroids 5 and 10. The absolute structures of hippuristanols were established by application of modified Mosher's method on 19. Compounds 14-19 have been found to exhibit significant cytotoxicity against several cancer cell lines.
Subject(s)
Anthozoa/chemistry , Antineoplastic Agents/isolation & purification , Steroids/isolation & purification , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Crystallography, X-Ray , Drug Screening Assays, Antitumor , Humans , Molecular Structure , Nuclear Magnetic Resonance, Biomolecular , Stereoisomerism , Steroids/chemistry , Steroids/pharmacology , Tumor Cells, CulturedABSTRACT
Five novel (22R,23S,24S)-steroids, hippuristerones E-I (1-5), have been isolated from the gorgonian coral Isis hippuris. The structures of steroids 1-5 were deduced by extensive 1D and 2D NMR studies ((1)H, (13)C, (1)H-(1)H COSY, HMQC, HMBC, and NOESY experiments). The structure of 1 was further supported by molecular mechanics calculations.