30 research outputs found

    Hydrogen-based technologies in maritime sector: technical analysis and prospective

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    The maritime transportation sector is one of the main contributors to global emissions of greenhouse gases (GHGs). The International Maritime Organization (IMO) has adopted a strategy to reduce these emissions from international shipping >50% by 2050, compared to 2008’s emissions. Therefore, ship owners need to adopt solutions to bring emissions within these and other future limits by means of environmentally friendly fuels (hydrogen or hydrogen carriers) and high efficiency propulsion technologies (fuel cells). This paper focuses on the replacement of the conventional Diesel genset installed on a hybrid small-size ferry, with an innovative system based on PEMFC technology. A real case scenario is investigated: the total energy/power demand of the vessel is determined basing on a typical operational profile. Then, a preliminary redesign of its powertrain configuration is proposed along with an energy management strategy. The analysis has allowed to define the hydrogen consumption for a daily operation. Finally, different storage technologies involving both compressed and liquefied hydrogen have been considered and compared, in order to identify ship’s weight and space requirements

    Transient Alteration of Cellular Redox Buffering before Irradiation Triggers Apoptosis in Head and Neck Carcinoma Stem and Non-Stem Cells

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    Background: Head and neck squamous cell carcinoma (HNSCC) is an aggressive and recurrent malignancy owing to intrinsic radioresistance and lack of induction of apoptosis. The major focus of this work was to design a transient glutathione depleting strategy during the course of irradiation of HNSCC in order to overcome their radioresistance associated with redox adaptation. Methodology/Principal Findings: Treatment of SQ20B cells with dimethylfumarate (DMF), a GSH-depleting agent, and L-Buthionine sulfoximine (BSO), an inhibitor of GSH biosynthesis 4 h before a 10 Gy irradiation led to the lowering of the endogenous GSH content to less than 10 % of that in control cells and to the triggering of radiation-induced apoptotic cell death. The sequence of biochemical events after GSH depletion and irradiation included ASK-1 followed by JNK activation which resulted in the triggering of the intrinsic apoptotic pathway through Bax translocation to mitochondria. Conclusions: This transient GSH depletion also triggered radiation-induced cell death in SQ20B stem cells, a key event to overcome locoregional recurrence of HNSCC. Finally, our in vivo data highlight the relevance for further clinical trials o

    Low relationship quality predicts scratch contagion during tense situations in orangutans (Pongo pygmaeus)

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    Primates show various forms of behavioral contagion that are stronger between kin and friends. As a result, behavioral contagion is thought to promote group coordination, social cohesion, and possibly state matching. Aside from contagious yawning, little is known about the contagious effect of other behaviors. Scratching is commonly observed during arousal and as such may play a role within group dynamics. While the Bornean orangutan (Pongo pygmaeus) is commonly considered the least social great ape, orangutans do engage in social interactions. Therefore, their social organization makes them a suitable case for studying the social function of behavioral contagion. Through behavioral observations of captive orangutans, we recorded all yawn and scratch events together with the corresponding behavior of all bystander group‐members. As yawning was rarely observed, no conclusions could be drawn regarding this behavior. Scratching was contagious and occurred within 90 s after the triggering scratch. Specifically, orangutans showed increased scratch contagion when they had seen a weakly bonded individual scratch during tense contexts. When the orangutan had not seen the triggering scratch, the contagiousness of scratching was not affected by context or relationship quality. Our results indicate that behavioral contagion is not simply higher between individuals with stronger social relationships, but that the contagiousness of behaviors may vary based on the context and on social factors. We discuss these findings in light of an adaptive function that may reduce aggression

    Bared-teeth displays in bonobos (Pan paniscus): An assessment of the power asymmetry hypothesis

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    Facial expressions are key to navigating social group life. The Power Asymmetry Hypothesis of Motivational Emancipation predicts that the type of social organization shapes the meaning of communicative displays in relation to an individual's dominance rank. The bared-teeth (BT) display represents one of the most widely observed communicative signals across primate species. Studies in macaques indicate that the BT display in despotic species is often performed unidirectionally, from low- to high-ranking individuals (signaling submission), whereas the BT display in egalitarian species is usually produced irrespective of dominance (mainly signaling affiliation and appeasement). Despite its widespread presence, research connecting BT displays to the power asymmetry hypothesis outside the Macaca genus remains scarce. To extend this knowledge, we investigated the production of BT in relation to social dominance in dyadic interactions (N = 11,377 events) of 11 captive bonobos (Pan paniscus). Although adult bonobos were more despotic than previously suggested in the literature, BT displays were produced irrespective of dominance rank. Moreover, while adults produced the BT exclusively during socio-sexual interactions, especially during periods of social tension, immature bonobos produced the BT in a wider number of contexts. As such, the results indicate that the communicative meaning of the BT display is consistent with signaling appeasement, especially in periods of social tension. Moreover, the BT display does not seem to signal social status, supporting the prediction for species with a high degree of social tolerance. These results advance our understanding of the origins of communicative signals and their relation to species' social systems

    A behavioral view on chimpanzee personality: Exploration tendency, persistence, boldness, and tool-orientation measured with group experiments

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    Human and nonhuman animals show personality: temporal and contextual consistency in behavior patterns that vary among individuals. In contrast to most other species, personality of chimpanzees, Pan troglodytes, has mainly been studied with non-behavioral methods. We examined boldness, exploration tendency, persistence and tool-orientation in 29 captive chimpanzees using repeated experiments conducted in an ecologically valid social setting. High temporal repeatability and contextual consistency in all these traits indicated they reflected personality. In addition, Principal Component Analysis revealed two independent syndromes, labeled exploration-persistence and boldness. We found no sex or rank differences in the trait scores, but the scores declined with age. Nonetheless, there was considerable inter-individual variation within age-classes, suggesting that behavior was not merely determined by age but also by dispositional effects. In conclusion, our study complements earlier rating studies and adds new traits to the chimpanzee personality, thereby supporting the existence of multiple personality traits among chimpanzees. We stress the importance of ecologically valid behavioral research to assess multiple personality traits and their association, as it allows inclusion of ape studies in the comparison of personality structures across species studied behaviorally, and furthers our attempts to unravel the causes and consequences of animal personality

    Bonobos ( Pan paniscus

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    In social animals, the fast detection of group members’ emotional expressions promotes swift and adequate responses, which is crucial for the maintenance of social bonds and ultimately for group survival. The dot-probe task is a well-established paradigm in psychology, measuring emotional attention through reaction times. Humans tend to be biased toward emotional images, especially when the emotion is of a threatening nature. Bonobos have rich, social emotional lives and are known for their soft and friendly character. In the present study, we investigated (i) whether bonobos, similar to humans, have an attentional bias toward emotional scenes compared with conspecifics showing a neutral expression, and (ii) which emotional behaviors attract their attention the most. As predicted, results consistently showed that bonobos’ attention was biased toward the location of the emotional versus neutral scene. Interestingly, their attention was grabbed most by images showing conspecifics such as sexual behavior, yawning, or grooming, and not as much—as is often observed in humans—by signs of distress or aggression. The results suggest that protective and affiliative behaviors are pivotal in bonobo society and therefore attract immediate attention in this species

    Low relationship quality predicts scratch contagion during tense situations in orangutans (Pongo pygmaeus)

    No full text
    Primates show various forms of behavioral contagion that are stronger between kin and friends. As a result, behavioral contagion is thought to promote group coordination, social cohesion, and possibly state matching. Aside from contagious yawning, little is known about the contagious effect of other behaviors. Scratching is commonly observed during arousal and as such may play a role within group dynamics. While the Bornean orangutan (Pongo pygmaeus) is commonly considered the least social great ape, orangutans do engage in social interactions. Therefore, their social organization makes them a suitable case for studying the social function of behavioral contagion. Through behavioral observations of captive orangutans, we recorded all yawn and scratch events together with the corresponding behavior of all bystander group‐members. As yawning was rarely observed, no conclusions could be drawn regarding this behavior. Scratching was contagious and occurred within 90 s after the triggering scratch. Specifically, orangutans showed increased scratch contagion when they had seen a weakly bonded individual scratch during tense contexts. When the orangutan had not seen the triggering scratch, the contagiousness of scratching was not affected by context or relationship quality. Our results indicate that behavioral contagion is not simply higher between individuals with stronger social relationships, but that the contagiousness of behaviors may vary based on the context and on social factors. We discuss these findings in light of an adaptive function that may reduce aggression
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