1,325 research outputs found

    Population structure and connectivity of tiger sharks (Galeocerdo cuvier) across the Indo-Pacific Ocean basin

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    Population genetic structure using nine polymorphic nuclear microsatellite loci was assessed for the tiger shark () at seven locations across the Indo-Pacific, and one location in the southern Atlantic. Genetic analyses revealed considerable genetic structuring ( > 0.14,

    Principles of Experimental Design for Big Data Analysis

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    Big Datasets are endemic, but are often notoriously difficult to analyse because of their size, heterogeneity and quality. The purpose of this paper is to open a discourse on the potential for modern decision theoretic optimal experimental design methods, which by their very nature have traditionally been applied prospectively, to improve the analysis of Big Data through retrospective designed sampling in order to answer particular questions of interest. By appealing to a range of examples, it is suggested that this perspective on Big Data modelling and analysis has the potential for wide generality and advantageous inferential and computational properties. We highlight current hurdles and open research questions surrounding efficient computational optimisation in using retrospective designs, and in part this paper is a call to the optimisation and experimental design communities to work together in the field of Big Data analysis.CCD was supported by an Australian Research Council’s Discovery Early Career Researcher Award funding scheme (DE160100741). CH would like to gratefully acknowledge support from the Medical Research Council (UK), the OxfordMAN Institute, and the EPSRC UK through the i-like Statistics programme grant. CCD, JMM and KM would like to acknowledge support from the Australian Research Council Centre of Excellence for Mathematical and Statistical Frontiers (ACEMS). Funding from the Australian Research Council for author KM is gratefully acknowledged

    Dynamics of cognitive functions in ageing and their relationship to education level = Динамика когнитивных функций при старении и их связь с уровнем образования

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    Age-related cognitive changes in the Russian population have not been sufficiently studied. Objective: to assess the time course of changes in cognitive functions (CF) in two serial measurements 9 years apart in the urban population of middle, elder, and senile age and their relationship to education level. Patients and methods. A random male and female sample of 45-69-year-old Novosibirsk residents (n=9360; HAPIEE project) was surveyed. CF was tested by standard methods. Resurvey was conducted in a random subsample (n=1663) included in this analysis. The mean follow-up period was 8.8 years (SD 1.1). Results and discussion. The test for semantic verbal fluency revealed its dynamic decline in all age groups, which was steeper in women than in men (p<0.001). Persons aged 70 years and older showed negative changes in memory, verbal fluency, and attention (p<0.001). Persons with primary (6%) and vocational (26%) education had steeper rates of decline in delayed recall (p=0.011; 0.038) than those with university education (35%). Conclusion. It is established that a dynamic decrease in CF begins at the age of 55–59 years; it is steeper among those aged 70 years and older. An age-related decline in memory function is accelerated in persons with lower educational levels

    Achimota Pararubulavirus 3: A New Bat-Derived Paramyxovirus of the Genus Pararubulavirus.

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    Bats are an important source of viral zoonoses, including paramyxoviruses. The paramyxoviral Pararubulavirus genus contains viruses mostly derived from bats that are common, diverse, distributed throughout the Old World, and known to be zoonotic. Here, we describe a new member of the genus Achimota pararubulavirus 3 (AchPV3) and its isolation from the urine of African straw-coloured fruit bats on primary bat kidneys cells. We sequenced and analysed the genome of AchPV3 relative to other Paramyxoviridae, revealing it to be similar to known pararubulaviruses. Phylogenetic analysis of AchPV3 revealed the failure of molecular detection in the urine sample from which AchPV3 was derived and an attachment protein most closely related with AchPV2-a pararubulavirus known to cause cross-species transmission. Together these findings add to the picture of pararubulaviruses, their sources, and variable zoonotic potential, which is key to our understanding of host restriction and spillover of bat-derived paramyxoviruses. AchPV3 represents a novel candidate zoonosis and an important tool for further study

    Strange Attractors in Dissipative Nambu Mechanics : Classical and Quantum Aspects

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    We extend the framework of Nambu-Hamiltonian Mechanics to include dissipation in R3R^{3} phase space. We demonstrate that it accommodates the phase space dynamics of low dimensional dissipative systems such as the much studied Lorenz and R\"{o}ssler Strange attractors, as well as the more recent constructions of Chen and Leipnik-Newton. The rotational, volume preserving part of the flow preserves in time a family of two intersecting surfaces, the so called {\em Nambu Hamiltonians}. They foliate the entire phase space and are, in turn, deformed in time by Dissipation which represents their irrotational part of the flow. It is given by the gradient of a scalar function and is responsible for the emergence of the Strange Attractors. Based on our recent work on Quantum Nambu Mechanics, we provide an explicit quantization of the Lorenz attractor through the introduction of Non-commutative phase space coordinates as Hermitian N×N N \times N matrices in R3 R^{3}. They satisfy the commutation relations induced by one of the two Nambu Hamiltonians, the second one generating a unique time evolution. Dissipation is incorporated quantum mechanically in a self-consistent way having the correct classical limit without the introduction of external degrees of freedom. Due to its volume phase space contraction it violates the quantum commutation relations. We demonstrate that the Heisenberg-Nambu evolution equations for the Quantum Lorenz system give rise to an attracting ellipsoid in the 3N23 N^{2} dimensional phase space.Comment: 35 pages, 4 figures, LaTe

    Research on health transition in Africa: time for action

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    With rapidly increasing globalization, trends towards unhealthy diets, obesity, sedentary lifestyles and unhealthy habits are resulting in an increased worldwide burden of chronic non-communicable diseases (NCDs). In Africa this means that health systems face the challenge of an increasing burden of NCDs and of continuing high morbidity and mortality from communicable diseases. This health transition represents an enormous challenge to Africa as the region with the least resources for an effective response. Whereas previous epidemics, including HIV, have caught Africa unprepared, the opportunity now arises to take the advancing wave of health transition in Africa seriously. Health research has a key role to play in meeting health and development goals, and must be responsive to changing disease patterns, such as health transition. There is an urgent need for research on health transition in Africa to enable countries to respond effectively to rapidly changing health needs

    Neural responses in parietal and occipital areas in response to visual events are modulated by prior multisensory stimuli

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    The effect of multi-modal vs uni-modal prior stimuli on the subsequent processing of a simple flash stimulus was studied in the context of the audio-visual 'flash-beep' illusion, in which the number of flashes a person sees is influenced by accompanying beep stimuli. EEG recordings were made while combinations of simple visual and audio-visual stimuli were presented. The experiments found that the electric field strength related to a flash stimulus was stronger when it was preceded by a multi-modal flash/beep stimulus, compared to when it was preceded by another uni-modal flash stimulus. This difference was found to be significant in two distinct timeframes--an early timeframe, from 130-160 ms, and a late timeframe, from 300-320 ms. Source localisation analysis found that the increased activity in the early interval was localised to an area centred on the inferior and superior parietal lobes, whereas the later increase was associated with stronger activity in an area centred on primary and secondary visual cortex, in the occipital lobe. The results suggest that processing of a visual stimulus can be affected by the presence of an immediately prior multisensory event. Relatively long-lasting interactions generated by the initial auditory and visual stimuli altered the processing of a subsequent visual stimulus.status: publishe

    Emotional Facial Expression Detection in the Peripheral Visual Field

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    BACKGROUND: In everyday life, signals of danger, such as aversive facial expressions, usually appear in the peripheral visual field. Although facial expression processing in central vision has been extensively studied, this processing in peripheral vision has been poorly studied. METHODOLOGY/PRINCIPAL FINDINGS: Using behavioral measures, we explored the human ability to detect fear and disgust vs. neutral expressions and compared it to the ability to discriminate between genders at eccentricities up to 40°. Responses were faster for the detection of emotion compared to gender. Emotion was detected from fearful faces up to 40° of eccentricity. CONCLUSIONS: Our results demonstrate the human ability to detect facial expressions presented in the far periphery up to 40° of eccentricity. The increasing advantage of emotion compared to gender processing with increasing eccentricity might reflect a major implication of the magnocellular visual pathway in facial expression processing. This advantage may suggest that emotion detection, relative to gender identification, is less impacted by visual acuity and within-face crowding in the periphery. These results are consistent with specific and automatic processing of danger-related information, which may drive attention to those messages and allow for a fast behavioral reaction
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