183 research outputs found

    Surveying rip current survivors: Preliminary insights into the experiences of being caught in rip currents

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    This paper begins a process of addressing a significant gap in knowledge about people's responses to being caught in rip currents. While rip currents are the primary hazard facing recreational ocean swimmers in Australia, debate exists about the best advice to give swimmers caught in rip currents. Such surf rescue advice - on what to do and how to respond when caught in a rip - relies on empirical evidence. However, at present, knowledge about swimmers reactions and responses to rip currents is limited. This gap is a considerable barrier to providing effective advice to beach goers and to understanding how this advice is utilised (or not) when actually caught in the rip current. This paper reports the findings of a pilot study that focussed on garnering a better understanding of swimmers' experiences when caught in rip currents. A large scale questionnaire survey instrument generated data about rip current survivors' demographics, knowledge of beach safety and their reactions and responses when caught in a rip current. A mix of online and paper surveys produced a total of 671 completed surveys. Respondents were predominantly an informed group in terms of rip current knowledge, beach experience and had a high self-rated swimming ability. Preliminary insights from the survey show that most respondents recalled a "swim across the rip/parallel to the beach" message when caught in the rip and most escaped unassisted by acting on this message. However, while nearly a quarter of respondents recalled a message of "not to panic", short answer responses revealed that the onset of panic inhibited some respondents from recalling or enacting any other type of beach safety message when caught in the rip current. Results also showed that despite the research sample being younger, competent and frequent ocean swimmers, they were more likely to swim at unpatrolled beaches and outside of the red and yellow safety flags. Moreover, they were still caught in a rip current and they panicked. The findings of this study have significant implications for a range of demographic groups of differing beach safety knowledge and swimming ability who may be caught in rip currents behave, we know very little about how beach goers may respond to being caught in them. © 2012 Author(s)

    Dispersal: an alternative mating tactic conditional on sex ratio and body size

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    Small male milkweed beetles are less successful at obtaining mates than are larger males. Larger males usually win fights and prevent smaller males from obtaining mates and from choosing larger more fecund females as mates. When sex ratios are male-biased, smaller males are particularly likely to experience these mating disadvantages. It follows that smaller males should be especially responsive to their local competitive environment and behave so as to minimize the mating disadvantages of their smaller size. This paper tests the hypothesis that smaller males disperse from host plant patches with male-biased sex ratios and remain in patches with female-biased sex ratios more readily than larger males.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46883/1/265_2004_Article_BF00299931.pd

    The Function of Anal Fin Egg-Spots in the Cichlid Fish Astatotilapia burtoni

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    Color and pigmentation patterns of animals are often targets of sexual selection because of their role in communication. Although conspicuous male traits are typically implicated with intersexual selection, there are examples where sex-specific displays play a role in an intrasexual context, e.g. when they serve as signals for aggression level and/or status. Here, we focus on the function of a conspicuous male ornament in the most species-rich tribe of cichlid fishes, the haplochromines. A characteristic feature of these ca. 1500 species are so-called egg-spots in form of ovoid markings on the anal fins of males, which are made up of carotenoid based pigment cells. It has long been assumed that these yellow, orange or reddish egg-spots play an important role in the courtship and spawning behavior of these maternal mouth-brooding fishes by mimicking the eggs of a conspecific female. The exact function of egg-spots remains unknown, however, and there are several hypotheses about their mode of action. To uncover the function of this cichlid-specific male ornament, we used female mate choice experiments and a male aggression test in the haplochromine species Astatotilapia burtoni. We manipulated the number and arrangement of egg-spots on the anal fins of males, or removed them entirely, and tested (1) female preference with visual contact only using egg-traps, (2) female preference with free contact using paternity testing with microsatellites and (3) male aggression. We found that females did not prefer males with many egg-spots over males with fewer egg-spots and that females tended to prefer males without egg-spots over males with egg-spots. Importantly, males without egg-spots sired clutches with the same fertilization rate as males with egg-spots. In male aggression trials, however, males with fewer egg-spots received significantly more attacks, suggesting that egg-spots are an important signal in intrasexual communication

    A conceptual governance framework for climate change adaptation and disaster risk reduction integration

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    Climate change adaptation (CCA) and disaster risk reduction (DRR) have similar targets and goals in relation to climate change and related risks. The integration of CCA in core DRR operations is crucial to provide simultaneous benefits for social systems coping with challenges posed by climate extremes and climate change. Although state actors are generally responsible for governing a public issue such as CCA and DRR integration, the reform of top-down governing modes in neoliberal societies has enlarged the range of potential actors to include non state actors from economic and social communities. These new intervening actors require in-depth investigation. To achieve this goal, the article investigates the set of actors and their bridging arrangements that create and shape governance in CCA and DRR integration. The article conducts a comprehensive literature review in order to retrieve main actors and arrangements. The article summarizes actors and arrangements into a conceptual governance framework that can be used as a backdrop for future research on the topic. However, this framework has an explorative form, which must be refined according to site- and context-specific variables, norms, or networks. Accordingly, this article promotes an initial application of the framework to different contexts. Scholars may adopt the framework as a roadmap with which to corroborate the existence of a theoretical and empirical body of knowledge on governance of CCA and DRR integration

    Sensorimotor input as a language generalisation tool: a neurorobotics model for generation and generalisation of noun-verb combinations with sensorimotor inputs

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    The paper presents a neurorobotics cognitive model explaining the understanding and generalisation of nouns and verbs combinations when a vocal command consisting of a verb-noun sentence is provided to a humanoid robot. The dataset used for training was obtained from object manipulation tasks with a humanoid robot platform; it includes 9 motor actions and 9 objects placing placed in 6 different locations), which enables the robot to learn to handle real-world objects and actions. Based on the multiple time-scale recurrent neural networks, this study demonstrates its generalisation capability using a large data-set, with which the robot was able to generalise semantic representation of novel combinations of noun-verb sentences, and therefore produce the corresponding motor behaviours. This generalisation process is done via the grounding process: different objects are being interacted, and associated, with different motor behaviours, following a learning approach inspired by developmental language acquisition in infants. Further analyses of the learned network dynamics and representations also demonstrate how the generalisation is possible via the exploitation of this functional hierarchical recurrent network

    Whisker Movements Reveal Spatial Attention: A Unified Computational Model of Active Sensing Control in the Rat

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    Spatial attention is most often investigated in the visual modality through measurement of eye movements, with primates, including humans, a widely-studied model. Its study in laboratory rodents, such as mice and rats, requires different techniques, owing to the lack of a visual fovea and the particular ethological relevance of orienting movements of the snout and the whiskers in these animals. In recent years, several reliable relationships have been observed between environmental and behavioural variables and movements of the whiskers, but the function of these responses, as well as how they integrate, remains unclear. Here, we propose a unifying abstract model of whisker movement control that has as its key variable the region of space that is the animal's current focus of attention, and demonstrate, using computer-simulated behavioral experiments, that the model is consistent with a broad range of experimental observations. A core hypothesis is that the rat explicitly decodes the location in space of whisker contacts and that this representation is used to regulate whisker drive signals. This proposition stands in contrast to earlier proposals that the modulation of whisker movement during exploration is mediated primarily by reflex loops. We go on to argue that the superior colliculus is a candidate neural substrate for the siting of a head-centred map guiding whisker movement, in analogy to current models of visual attention. The proposed model has the potential to offer a more complete understanding of whisker control as well as to highlight the potential of the rodent and its whiskers as a tool for the study of mammalian attention
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