106 research outputs found

    A hypothetico-deductive approach to assessing the social function of chemical signalling in a non-territorial solitary carnivore

    Get PDF
    The function of chemical signalling in non-territorial solitary carnivores is still relatively unclear. Studies on territorial solitary and social carnivores have highlighted odour capability and utility, however the social function of chemical signalling in wild carnivore populations operating dominance hierarchy social systems has received little attention. We monitored scent marking and investigatory behaviour of wild brown bears Ursus arctos, to test multiple hypotheses relating to the social function of chemical signalling. Camera traps were stationed facing bear ‘marking trees’ to document behaviour by different age sex classes in different seasons. We found evidence to support the hypothesis that adult males utilise chemical signalling to communicate dominance to other males throughout the non-denning period. Adult females did not appear to utilise marking trees to advertise oestrous state during the breeding season. The function of marking by subadult bears is somewhat unclear, but may be related to the behaviour of adult males. Subadults investigated trees more often than they scent marked during the breeding season, which could be a result of an increased risk from adult males. Females with young showed an increase in marking and investigation of trees outside of the breeding season. We propose the hypothesis that females engage their dependent young with marking trees from a young age, at a relatively ‘safe’ time of year. Memory, experience, and learning at a young age, may all contribute towards odour capabilities in adult bears

    Integrating Positive and Clinical Psychology: Viewing Human Functioning as Continua from Positive to Negative Can Benefit Clinical Assessment, Interventions and Understandings of Resilience

    Get PDF
    In this review we argue in favour of further integration between the disciplines of positive and clinical psychology. We argue that most of the constructs studied by both positive and clinical psychology exist on continua ranging from positive to negative (e.g., gratitude to ingratitude, anxiety to calmness) and so it is meaningless to speak of one or other field studying the “positive” or the “negative”. However, we highlight historical and cultural factors which have led positive and clinical psychologies to focus on different constructs; thus the difference between the fields is more due to the constructs of study rather than their being inherently “positive” or “negative”. We argue that there is much benefit to clinical psychology of considering positive psychology constructs because; (a) constructs studied by positive psychology researchers can independently predict wellbeing when accounting for traditional clinical factors, both cross-sectionally and prospectively, (2) the constructs studied by positive psychologists can interact with risk factors to predict outcomes, thereby conferring resilience, (3) interventions that aim to increase movement towards the positive pole of well-being can be used encourage movement away from the negative pole, either in isolation or alongside traditional clinical interventions, and (4) research from positive psychology can support clinical psychology as it seeks to adapt therapies developed in Western nations to other cultures

    Too many cooks: Coordinating multi-agent collaboration through inverse planning

    No full text
    © 2020 International Foundation for Autonomous Agents and Multiagent Systems (IFAAMAS). All rights reserved. Humans collaborate in dynamic and flexible ways. Collaboration requires agents to coordinate their behavior on the fly, sometimes jointly solving a single task together and other times dividing it up into sub-tasks to work on in parallel. We develop Bayesian Delegation, a learning mechanism for decentralized multi-agent coordination that enables agents to rapidly infer the sub-tasks that other agents are working on by inverse planning. These inferences enable agents to determine, in the absence of communication, whether to plan jointly with others or work on complementary sub-tasks. We test this model in a suite of decentralized multi-agent environments inspired by cooking problems. To succeed, agents must coordinate both their high-level plans (sub-task) and their low-level actions (avoiding collisions). Including joint sub-tasks in the prior of Bayesian delegation enables agents to carry out sub-tasks that neither agent can finish independently. The full system outperforms lesioned systems that are missing one or more of these capabilities

    Abciximab, ticlopidine, and concomitant abciximab-ticlopidine therapy: Ex vivo platelet aggregation inhibition profiles in patients undergoing percutaneous coronary interventions

    No full text
    Background We examined the ex vivo platelet aggregation profiles of patients who underwent percutaneous coronary intervention and received either abciximab, ticlopidine, or both agents.Study Design and Methods The trial was a prospective, nonrandomized, single-center, open-label study of 42 patients undergoing percutaneous coronary intervention who received the Following regimens: group 1, abciximab (0.25 mg/kg bolus and 12-hour, 0.125 mu g/kg per minute infusion); group 2, ticlopidine (250 mg twice daily For 14 consecutive days, initiated 12 to 18 hours before intervention); group 3, abciximab plus ticlopidine initiated 12 to 18 hours before procedure; and group 4, abciximab plus ticlopidine initiated 72 to 96 hours before procedure. Platelet aggregation measurements to adenosine diphosphate (ADP) and a thrombin receptor activating peptide (TRAP, 8 mu mol/l) were obtained before ticlopidine treatment, after initiation of ticlopidine, and immediately before abciximab treatment and intervention, then at several time periods after onset of abciximab treatment. Platelet surface abciximab levels were monitored by flow cytometry.Results Neither ticlopidine regimen resulted in appreciable platelet inhibition before intervention and before administration of abciximab. In the ticlopidine-only arm, suppression of platelet aggregation to the weakest stimuli (5 mu mol/l ADP; 23% +/- 7.5%) was detected within 24 hours after intervention, with maximal inhibition to both 5 and 20 mu mol/L ADP observed 7 days after intervention (48% +/- 7.9% and 18% +/- 8.7%, respectively). In contrast, ticlopidine marginally suppressed TRAP-mediated platelet activation at times when maximal effects on ADP-mediated platelet aggregation were evident. Neither ticlopidine regimen appreciably enhanced platelet inhibition during or shortly after cessation of abciximab treatment. For all 3 abciximab treatment arms, profound inhibition of ADP-induced (>80%) and TRAP-induced (>65%) platelet aggregation was observed 2 hours after treatment. In the abciximab-only arm, platelet aggregation responses gradually recovered, with the rate of response directly proportional to the strength of stimuli. However, in the ticlopidine plus abciximab arms, recovery of platelet aggregation at later times (7 and 14 days) reached a plateau and reflected the extent of inhibition observed in ticlopidine-treated patients. No difference in the clearance of surface-bound abciximab from circulating platelets was observed between the abciximab and abciximab plus ticlopidine arms.Conclusions Concomitant abciximab plus ticlopidine treatment yields a platelet inhibition profile that is a composite of the effects of the 2 agents. In the early stages of treatment, inhibition of ex vivo platelet aggregation was mediated primarily by abciximab; effects were more moderate and were predominately mediated by ticlopidine
    corecore