An Improved Time-Domain Inverse Technique for Localization and Quantifcation of Rotating Sound Sources

The time-domain inverse technique based on the time-domain rotating equivalent source method has been proposed to localize and quantify rotating sound sources. However, this technique encounters two problems to be addressed: one is the time-consuming process of solving the transcendental equation at each time step, and the other is the difculty of controlling the instability problem due to the time-varying transfer matrix. In view of that, an improved technique is proposed in this paper to resolve these two problems. In the improved technique, a de-Dopplerization method in the time-domain rotating reference frame is frst applied to eliminate the Doppler efect caused by the source rotation in the measured pressure signals, and then the restored pressure signals without the Doppler efect are used as the inputs of the time-domain stationary equivalent source method to locate and quantify sound sources. Compared with the original technique, the improved technique can avoid solving the transcendental equation at each time step, and facilitate the treatment of the instability problem because the transfer matrix does not change with time. Numerical simulation and experimental results show that the improved technique can eliminate the Doppler efect efectively, and then localize and quantify the rotating nonstationary or broadband sources accurately. The results also demonstrate that the improved technique can guarantee a more stable reconstruction and compute more efciently than the original one.

The pikas of China: a review of current research priorities and challenges for conservation

Of the approximately 30 extant species of pika(Ochotona;Ochotonidae;Lagomorpha),at least 23 occur in China.Of these,8 are endemic,and 3 are classified as Endangered by the IUCN.Research into most Chinese species is scarce,and there is much to learn about basic aspects of their ecology.We reviewed the literature on the 23 Chinese Ochotona species,with the aim of highlighting knowledge gaps and biases in research allocation.Specifically,we identify(1)which pika species receive the most attention from researchers,(2)which topics are the most frequently studied,and(3)how well research satisfies conservation priorities.We covered a total of 879 articles,most of which were written in English or Chinese.Around 75%of all publications focused on the plateau pika Ochotona curzoniae.Seven species were represented by 10 or fewer publications each.Endangered and endemic species were particularly poorly represented.204 papers treated pikas as a pest,while 13 studied conservation issues.Nine species were considered possible targets for pest control,including some poorly known endemics.We make some recommendations on how research into Chinese Ochotona could be improved,including:(1)recognizing that the current species-level taxonomy may be an ineffective way to prioritize conservation research in Ochotona,(2)directing more research toward threatened and endemic species,subspecies,and populations,(3)researching the ecosystem engineering effects of pikas,(4)collecting basic data on natural history of the many understudied species,and(5)researching threats,including climate change and pest control campaigns.

Nicotine and its metabolite cotinine target MD2 and inhibit TLR4 signaling

Nicotine is the principal alkaloid of tobacco often manufactured into cigarettes and belongs to a highly addictive class of drugs.Nicotine attenuates the neuroinflammation induced by microglial activation.However,the molecular target(s)underlying anti-inflammatory action of nicotine has not been fully understood.Considering the psychoactive substances morphine,cocaine,and methamphetamine act as xenobiotic-associated molecular patterns and can be specifically sensed by the innate immune receptor Toll-like receptor 4(TLR4),here we sought to delineate whether nicotine and/or its metabolite cotinine may be recognized by the innate immune system via myeloid differentiation protein 2(MD2).