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Management of Acute Type B Aortic Dissection

Veterinarians need to be part of West Nile disease storytelling

Ultrasound-Guided Paracentesis

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Safety and Efficacy of Obicetrapib in Patients at High Cardiovascular Risk

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Even dinosaurs weren’t safe from this giant croc-like predator

Third-party imitation is not restricted to humans

Abstract Imitation of cultural practices is ubiquitous in humans and often involves faithful copying of intransitive (i.e., non-object directed) gestures and societal norms which play a crucial role in human cumulative cultural evolution. Apart from learning these directly from a tutor, humans often learn passively as third-party observers from the interactions of two or more individuals. Whether third-party imitation has evolved outside humans remains unknown. In the current study, we investigated whether undomesticated blue-throated macaws ( Ara glaucogularis ) could imitate in a third-party setting. A naïve test group ( N  = 6) passively observed a conspecific demonstrator performing rare intransitive actions in response to specific human gestural commands. Directly afterwards, the observer received the same gestural commands and performance-contingent rewards. An equally naïve control group ( N  = 5) was tested correspondingly, in the absence of third-party demonstrations. The test group learned more target actions (mean = 4.16 versus mean = 2.2) in response to the specific commands, significantly faster and performed them more accurately than the control group. The test group also spontaneously imitated some of the actions even before they received any gestural commands or rewards. Our findings show that third-party imitation, even for intransitive actions, exists outside humans, allowing for rapid adaption to group specific behaviours and possibly cultural conventions in parrots.

Estimations of effective doses received from naturally occurring radioactivity in polymetallic nodules from the deep sea

Abstract The strategic importance of metals found in deep-sea polymetallic nodules has spurred a surge in interest for their exploitation. However, nodules are known to incorporate radionuclides during their growth, so that any industrial processing would involve classifying them as naturally occurring radioactive materials (NORM). As the start of deep-sea mining gets closer, concerns about elevated exposure to radiation that could result from the handling of nodules has recently been raised. In this study, we address this issue within the framework of radiation protection regulations. For the first time, we present estimates of effective doses associated with laboratory work and industrial-scale exploitation, transportation and metallurgical processing of polymetallic nodules. Estimates are based on an analysis of all long-lived radionuclides from the three natural decay chains of uranium-238, uranium-235 and thorium-232 and on radon exhalation rates from dry nodules. We show that effective doses for laboratory workplaces are well below the threshold of 1 millisievert per calendar year (mSv/a) for occupational exposure, even under the most conservative assumptions. Furthermore, we find that the effective doses for personnel on nodule transport vessels and metallurgical processing facilities may exceed the threshold in a conservative scenario. However, with standard radiation protection and mitigation measures common in other NORM-affected industries, effective doses can be kept well below the occupational exposure limit.