Rational imitation for robots: the cost difference model

© 2017, © The Author(s) 2017. Infants imitate behaviour flexibly. Depending on the circumstances, they copy both actions and their effects or only reproduce the demonstrator’s intended goals. In view of this selective imitation, infants have been called rational imitators. The ability to selectively and adaptively imitate behaviour would be a beneficial capacity for robots. Indeed, selecting what to imitate is an outstanding unsolved problem in the field of robotic imitation. In this paper, we first present a formalized model of rational imitation suited for robotic applications. Next, we test and demonstrate it using two humanoid robots

Dominant Glint Based Prey Localization in Horseshoe Bats: A Possible Strategy for Noise Rejection

Rhinolophidae or Horseshoe bats emit long and narrowband calls. Fluttering insect prey generates echoes in which amplitude and frequency shifts are present, i.e. glints. These glints are reliable cues about the presence of prey and also encode certain properties of the prey. In this paper, we propose that these glints, i.e. the dominant glints, are also reliable signals upon which to base prey localization. In contrast to the spectral cues used by many other bats, the localization cues in Rhinolophidae are most likely provided by self-induced amplitude modulations generated by pinnae movement. Amplitude variations in the echo not introduced by the moving pinnae can be considered as noise interfering with the localization process. The amplitude of the dominant glints is very stable. Therefore, these parts of the echoes contain very little noise. However, using only the dominant glints potentially comes at a cost. Depending on the flutter rate of the insect, a limited number of dominant glints will be present in each echo giving the bat a limited number of sample points on which to base localization. We evaluate the feasibility of a strategy under which Rhinolophidae use only dominant glints. We use a computational model of the echolocation task faced by Rhinolophidae. Our model includes the spatial filtering of the echoes by the morphology of the sonar apparatus of Rhinolophus rouxii as well as the amplitude modulations introduced by pinnae movements. Using this model, we evaluate whether the dominant glints provide Rhinolophidae with enough information to perform localization. Our simulations show that Rhinolophidae can use dominant glints in the echoes as carriers for self-induced amplitude modulations serving as localization cues. In particular, it is shown that the reduction in noise achieved by using only the dominant glints outweighs the information loss that occurs by sampling the echo

Review of European guidelines on palliative sedation: a foundation for the updating of the European Association for Palliative Care framework

in 2009, the European Association for Palliative Care (EAPC) developed a framework on palliative sedation, acknowledging this practice as an important and ethically acceptable intervention of last resort for terminally ill patients experiencing refractory symptoms. Before and after that, other guidelines on palliative sedation have been developed in Europe with variations in terminology and concepts. As part of the Palliative Sedation project (Horizon 2020 Funding No. 825700), a revision of the EAPC framework is planned. The aim of this article is to analyze the most frequently used palliative sedation guidelines as reported by experts from eight European countries to inform the discussion of the new framework. The three most reported documents per country were identified through an online survey among 124 clinical experts in December 2019. Those meeting guideline criteria were selected. Their content was assessed against the EAPC framework on palliative sedation. The quality of their methodology was evaluated with the Appraisal Guideline Research and Evaluation (AGREE) II instrument. Nine guidelines were included. All recognize palliative sedation as a last-resort treatment for refractory symptoms, but the criterion of refractoriness remains a matter of debate. Most guidelines recognize psychological or existential distress as (part of) an indication and some make specific recommendations for such cases. All agree that the assessment should be multiprofessional, but they diverge on the expertise required by the attending physician/team. Regarding decisions on hydration and nutrition, it is proposed that these should be independent of those for palliative sedation, but there is no clear consensus on the decision-making process. Several weaknesses were highlighted, particularly in areas of rigor of development and applicability. The identified points of debate and methodological weaknesses should be considered in any update or revision of the guidelines analyzed to improve the quality of their content and the applicability of their recommendations

Simulated trust : a cheap social learning strategy

Animals use heuristic strategies to determine from which conspecifics to learn socially. This leads to directed social learning. Directed social learning protects them from copying non-adaptive information. So far, the strategies of animals, leading to directed social learning, are assumed to rely on (possibly indirect) inferences about the demonstrator's success. As an alternative to this assumption, we propose a strategy that only uses self-established estimates of the pay-offs of behavior. We evaluate the strategy in a number of agent-based simulations. Critically, the strategy's success is warranted by the inclusion of an incremental learning mechanism. Our findings point out new theoretical opportunities to regulate social learning for animals. More broadly, our simulations emphasize the need to include a realistic learning mechanism in game-theoretic studies of social learning strategies, and call for re-evaluation of previous findings

Interaction between vinblastine and ionizing radiation in the mouse MO(4) fibrosarcoma in-vivo.

The effect of combining vinblastine (VLB) and ionizing radiation (IR) on tumor response was investigated in CDF1 mice bearing the MO4 mouse fibrosarcoma. Favorable interactions were assumed to occur if VLB treatment caused accumulation of cells in metaphase (M-)phase at the time of IR. High pressure liquid chromatography (HPLC) measurements showed that VLB administered at 2.0 mg/kg (0.4 maximal tolerated dose, MTD) was taken up rapidly by the tumor in vivo, and that sufficient concentrations of VLB were achieved to cause blocking of tumor cells in M-phase. However, different treatment schedules of the combination of 2.5 mg/kg VLB (0.5 MTD) and 10 Gy IR resulted in additive tumor responses. The best therapeutic response was observed when IR was given 6 hours after intravenous injection of VLB. In order to increase the therapeutic response, we attempted to enhance the accumulation of cells in M-phase by treating mice with VLB at the MTD. The maximum percentage of tumor cells that could be accumulated in mitosis by a single intravenous bolus of VLB at the MTD was around 13%. The results show that this will probably be insufficient for significant IR enhancement.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

How to measure the effects and potential adverse events of palliative sedation?:An integrative review

Background: Palliative sedation is the monitored use of medications intended to relieve refractory suffering. The assessment of palliative sedation has been focused on the assess of the level of consciousness but a more comprehensive approach to assessment is needed. Aim: To understand how the potential effects and possible adverse events of palliative sedation in Palliative Care patients are measured. Design: Integrative review of most recent empirical research. Data sources: Cochrane Library, Embase, Medline, PubMed, and CINAHL were searched (2010–2020) using the terms sedation, palliative care, terminal care, assessment. Limits included studies in English and adults. Inclusion criteria were: scientific assessment papers, effects and complications of palliative sedation; patients with incurable illness. Results: Out of 588 titles, 26 fulfilled inclusion criteria. The Discomfort Scale-Dementia of Alzheimer Type and Patient Comfort Score were used to assess comfort. The Richmond Agitation-Sedation Scale and The Ramsay Sedation Scale are the most used to measure its effect. Refractory symptoms were assessed through multi-symptom or specific scales; except for psychological or existential distress. Delirium was assessed using the Memorial Delirium Assessment Scale and pain through the Critical Care Pain Observation Tool. The use of technical approaches to monitor effects is upcoming. There is lack of measurement of possible adverse events and variability in timing measurement. Conclusions: There are palliative care validated instruments to assess the sedation effect but this review shows the need for a more standardized approach when assessing it. Instruments should be used within an experienced and trained expert, providing a holistic assessment