Quantifying the biomimicry gap in biohybrid systems

Biohybrid systems in which robotic lures interact with animals have become compelling tools for probing and identifying the mechanisms underlying collective animal behavior. One key challenge lies in the transfer of social interaction models from simulations to reality, using robotics to validate the modeling hypotheses. This challenge arises in bridging what we term the "biomimicry gap", which is caused by imperfect robotic replicas, communication cues and physics constrains not incorporated in the simulations that may elicit unrealistic behavioral responses in animals. In this work, we used a biomimetic lure of a rummy-nose tetra fish (Hemigrammus rhodostomus) and a neural network (NN) model for generating biomimetic social interactions. Through experiments with a biohybrid pair comprising a fish and the robotic lure, a pair of real fish, and simulations of pairs of fish, we demonstrate that our biohybrid system generates high-fidelity social interactions mirroring those of genuine fish pairs. Our analyses highlight that: 1) the lure and NN maintain minimal deviation in real-world interactions compared to simulations and fish-only experiments, 2) our NN controls the robot efficiently in real-time, and 3) a comprehensive validation is crucial to bridge the biomimicry gap, ensuring realistic biohybrid systems

Οι έννομες σχέσεις των μερών στη σύμβαση leasing σε περίπτωση νομικών-πραγματικών ελαττωμάτων του πράγματος

Η παρούσα εργασία πραγματεύεται τις έννομες σχέσεις των μερών που συμβάλλονται στη σύμβαση χρηματοδοτικής μίσθωσης όταν παρουσιάζονται πραγματικά ή νομικά ελαττώματα στο πράγμα. Αρχικά, γίνεται μια συνοπτική αναφορά στη σύμβαση χρηματοδοτικής μίσθωσης γενικά και στη νομική της φύση. Εν συνεχεία, αναπτύσσονται τα δικαιώματα και οι υποχρεώσεις του μισθωτή, του εκμισθωτή και του προμηθευτή. Περαιτέρω, αναλύονται πιο συγκεκριμένα κάποιες περιπτώσεις διαμόρφωσης των εννόμων σχέσεων τους σε περίπτωση ελαττώματος του πράγματος. Τέλος, γίνεται αναφορά στους τρόπους λήξης της σύμβασης.This paper deals with the legal relationships of the parties to the lease agreement when there are actual or legal defects in the item. First, a brief reference is made to the lease agreement in general and to its legal nature. The rights and obligations of the lessee, the lessor and the supplier are then developed. Furthermore, some cases of formation of their legal relations in case of defect of the item are analyzed more specifically. Finally, reference is made to the ways of termination of the contract

Εμπειρική ανάλυση της αποτελεσματικότητας του συντελεστή βήτα

Είναι γνωστό από την θεωρία χαρτοφυλακίου, ότι οι ιστορικές αποδόσεις (returns) των μετοχών μπορούν να χρησιμοποιηθούν για να προσδιοριστεί ο συστηματικός κίνδυνος αυτών των μετοχών, ο οποίος μετράτε μέσα από τον συντελεστή β. Ο βήτα εκτιμάται συνήθως με ημερήσια (daily), εβδομαδιαία (weekly) ή μηνιαία (monthly) ιστορικά δεδομένα αποδόσεων (returns). Ωστόσο η θεωρία δεν διευκρινίζει ποια συχνότητα δεδομένων είναι η κατάλληλη για την καλύτερη εκτίμηση του. Η χρήση διαφορετικών συχνοτήτων δεδομένων μας οδηγούν σε διαφορετικούς συντελεστές βήτα, ακόμα και όταν υπολογίζονται για το ίδιο χρονικό διάστημα. Αυτό το φαινόμενο είναι γνωστό στην βιβλιογραφία ως intervaling effect. Σε αυτή την εργασία θα προσπαθήσουμε να μελετήσουμε εμπειρικά το πιο πάνω φαινόμενο, χρησιμοποιώντας πέντε διαφορετικούς δείκτες από το χρηματιστήριο Αμερικής εκτιμώντας τα αντίστοιχα βήτα, με ημερήσια, εβδομαδιαία και μηνιαία δεδομένα. Επιπρόσθετα θα γίνει επισκόπηση προηγούμενων μελετών όπως αυτές αναφέρονται στη βιβλιογραφία που θα χρησιμοποιήσουμε σχετικά με τον συντελεστή βήτα, ώστε να έχουμε μια πιο σφαιρική άποψη για την αποτελεσματικότητα του σε διάφορα επίπεδα.It is known from portfolio theory that the historical returns of shares can be used to determine the systemic risk of these shares, which you measure through factor beta. Beta is usually estimated with daily, weekly or monthly historical returns. However, the theory does not specify which data frequency is appropriate for its best estimation. Using different data frequencies leads us to different beta coefficients, even when calculated for the same time period. This phenomenon is known in the literature as the intervaling effect. In this paper we will try to study the above phenomenon empirically, using five different indicators from the US stock market estimating the respective beta, with daily, weekly and monthly data. In addition, previous studies as reviewed in the literature on beta will be reviewed to provide a more comprehensive view of its effectiveness at various levels

Predicting long-term collective animal behavior with deep learning

Deciphering the social interactions that govern collective behavior in animal societies has greatly benefited from advancements in modern computing. Computational models diverge into two kinds of approaches: analytical models and machine learning models. This work introduces a deep learning model for social interactions in the fish species Hemigrammus rhodostomus, and compares its results to experiments and to the results of a state-of-the-art analytical model. To that end, we propose a systematic methodology to assess the faithfulness of a model, based on the introduction of a set of stringent observables. We demonstrate that machine learning models of social interactions can directly compete against their analytical counterparts. Moreover, this work demonstrates the need for consistent validation across different timescales and highlights which design aspects critically enables our deep learning approach to capture both short- and long-term dynamics. We also show that this approach is scalable to other fish species

Safety-Aware Robot Damage Recovery Using Constrained Bayesian Optimization and Simulated Priors

International audienceThe recently introduced Intelligent Trial-and-Error (IT&E) algorithm showed that robots can adapt to damage in a matter of a few trials. The success of this algorithm relies on two components: prior knowledge acquired through simulation with an intact robot, and Bayesian optimization (BO) that operates on-line, on the damaged robot. While IT&E leads to fast damage recovery, it does not incorporate any safety constraints that prevent the robot from attempting harmful behaviors. In this work, we address this limitation by replacing the BO component with a constrained BO procedure. We evaluate our approach on a simulated damaged humanoid robot that needs to crawl as fast as possible, while performing as few unsafe trials as possible. We compare our new " safety-aware IT&E " algorithm to IT&E and a multi-objective version of IT&E in which the safety constraints are dealt as separate objectives. Our results show that our algorithm outperforms the other approaches, both in crawling speed within the safe regions and number of unsafe trials

Imatinib Mesylate Induces Necroptotic Cell Death and Impairs Autophagic Flux in Human Cardiac Progenitor Cells

The receptor tyrosine kinase inhibitor imatinib improves patient cancer survival but is linked to cardiotoxicity. This study investigated imatinib’s effects on cell viability, apoptosis, autophagy, and necroptosis in human cardiac progenitor cells in vitro. Imatinib reduced cell viability (75.9 ± 2.7% vs. 100.0 ± 0.0%) at concentrations comparable to peak plasma levels (10 µM). Imatinib reduced cells’ TMRM fluorescence (74.6 ± 6.5% vs. 100.0 ± 0.0%), consistent with mitochondrial depolarisation. Imatinib increased lysosome and autophagosome content as indicated by LAMP2 expression (2.4 ± 0.3-fold) and acridine orange fluorescence (46.0 ± 5.4% vs. 9.0 ± 3.0), respectively. Although imatinib increased expression of autophagy-associated proteins and also impaired autophagic flux, shown by proximity ligation assay staining for LAMP2 and LC3II (autophagosome marker): 48 h of imatinib treatment reduced visible puncta to 2.7 ± 0.7/cell from 11.3 ± 2.1 puncta/cell in the control. Cell viability was partially recovered by autophagosome inhibition by wortmannin, with the viability increasing 91.8 ± 8.2% after imatinib-wortmannin co-treatment (84 ± 1.5% after imatinib). Imatinib-induced necroptosis was associated with an 8.5 ± 2.5-fold increase in mixed lineage kinase domain-like pseudokinase activation. Imatinib-induced toxicity was rescued by RIP1 inhibition: 88.6 ± 3.0% vs. 100.0 ± 0.0% in the control. Imatinib applied to human cardiac progenitor cells depolarises mitochondria and induces cell death through necroptosis, recoverable by RIP1 inhibition, with a partial role for autophagy

Presentation and management of keloid scarring following median sternotomy: a case study

<p>Abstract</p> <p>Introduction</p> <p>Keloid scars following median sternotomy are rare and occur more frequently in pigmented skin. Different management strategies have been described with variable success. We present a case of keloid scar formation following cardiac surgery including our management and the final aesthetic result.</p> <p>Case description</p> <p>A 64 year old female of fair complexion underwent mitral valve replacement. The procedure and postoperative recovery were uncomplicated, however, during the following year, thick keloid scars formed over the incision sites. Initial non surgical measures failed to relieve pain and did not offer any tangible aesthetic benefit. Eventually surgical excision was attempted. She presented to our clinic for nine months follow up with significant improvement in pain and aesthetic result.</p> <p>Discussion and Evaluation</p> <p>Several theories have attempted to explore the pathophysiology of keloid scar formation. A number of predisposing factors have been documented however none existed in this case. A variety of invasive and non invasive approaches have been described but significant differences in success rates and methodology of investigations still precludes a standardized management protocol.</p> <p>Conclusions</p> <p>In this case study a rare presentation of keloid scar has been presented. The variety of methods used to improve pain and aesthetic result demonstrates the propensity of keloid scars to recur and the therapeutic challenges that surgeons have to face in their quest for a satisfactory patient outcome.</p

Gastrointestinal stromal tumor masquerading as a lung neoplasm. A case presentation and literature review

Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal tract. Their incidence in the esophagus is 1%–3%. Never has a GIST been documented to directly invade the lung. We report a primary esophageal GIST with direct invasion into the lung parenchyma, presenting predominantly with respiratory symptoms. We include a retrospective literature review. Although the principle 'common things are common' usually guides our everyday clinical practice, this case emphasizes that rare entities can mimic common pathologies and underlines the importance of having a clearly defined differential diagnostic list which should be meticulously scrutinized

Current and prospective pharmacotherapies for the treatment of pleural mesothelioma

Introduction: Mesothelioma is a rare asbestos-linked cancer with an expected incidence peak between 2015–2030. Therapies remain ineffective, thus developing and testing novel treatments is important for both oncologists and researchers. Areas covered: After describing mesothelioma and the shortcomings of current therapies, the article discusses numerous therapies in turn such as immunotherapy (passive and active), gene therapy (such as suicide gene therapy) and targeted therapy such as tyrosine kinase inhibitors. The bases for different therapies and clinical trials at different phases are also described. The article concludes by detailing possible reasons for therapy failure. Expert opinion: Despite the many attempts to uncover new therapeutic options, mesothelioma is still an orphan disease, complicated by factors such as the inflammatory microenvironment and low mutational load. Our opinion is that uncovering the biological mechanisms behind mesothelioma development will assist therapy development. The lack of efficacy of tyrosine kinase inhibitors and modest anti-angiogenic activity indicates a less relevant role for tumor cell proliferation and neoangiogenesis, thus the shortcut of treating mesothelioma with therapies from other cancers may be unsound. Conversely, many lines of evidence indicate that focussing on the survival mechanisms that tumor cells exploit may yield better therapeutics, particularly nutrition and cellular machinery