The Use of Gamma-ray Bursts as Direction and Time Markers in SETI Strategies

When transmitting a signal over a large distance it is more efficient to send a brief beamed signal than a continuous omni-directional transmission but this requires that the receiver knows where and when to look for the transmission. For SETI, the use of various natural phenomena has previously been suggested to achieve the desired synchronization. Here it is proposed that gamma-ray bursts may well the best ``synchronizers'' of all currently known phenomena due to their large intrinsic luminosities, high occurrence rate, isotropic sky distribution, large distance from the Galaxy, short duration, and easy detectability. For targeted searches, precise positions for gamma-ray bursts are required together with precise distance measurements to a target star. The required burst position determinations are now starting to be obtained, aided in large part by the discovery of optical afterglows. Good distance measurements are currently available from Hipparcos and even better measurements should be provided by spacecraft now being developed. For non-targeted searches, positional accuracies simply better than a detector's field of view may suffice but the time delay between the detection of a gamma-ray burst and the reception of the transmitted signal cannot be predicted in an obvious way.Comment: 8 pages, accepted for publication in PAS

Ethical Considerations of Using Machine Learning for Decision Support in Occupational Health:An Example Involving Periodic Workers' Health Assessments

Purpose Computer algorithms and Machine Learning (ML) will be integrated into clinical decision support within occupational health care. This will change the interaction between health care professionals and their clients, with unknown consequences. The aim of this study was to explore ethical considerations and potential consequences of using ML based decision support tools (DSTs) in the context of occupational health. Methods We conducted an ethical deliberation. This was supported by a narrative literature review of publications about ML and DSTs in occupational health and by an assessment of the potential impact of ML-DSTs according to frameworks from medical ethics and philosophy of technology. We introduce a hypothetical clinical scenario from a workers' health assessment to reflect on biomedical ethical principles: respect for autonomy, beneficence, non-maleficence and justice. Results Respect for autonomy is affected by uncertainty about what future consequences the worker is consenting to as a result of the fluctuating nature of ML-DSTs and validity evidence used to inform the worker. A beneficent advisory process is influenced because the three elements of evidence based practice are affected through use of a ML-DST. The principle of non-maleficence is challenged by the balance between group-level benefits and individual harm, the vulnerability of the worker in the occupational context, and the possibility of function creep. Justice might be empowered when the ML-DST is valid, but profiling and discrimination are potential risks. Conclusions Implications of ethical considerations have been described for the socially responsible design of ML-DSTs. Three recommendations were provided to minimize undesirable adverse effects of the development and implementation of ML-DSTs