41 research outputs found

    Landscape of international event-based biosurveillance

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    Event-based biosurveillance is a scientific discipline in which diverse sources of data, many of which are available from the Internet, are characterized prospectively to provide information on infectious disease events. Biosurveillance complements traditional public health surveillance to provide both early warning of infectious disease events and situational awareness. The Global Health Security Action Group of the Global Health Security Initiative is developing a biosurveillance capability that integrates and leverages component systems from member nations. This work discusses these biosurveillance systems and identifies needed future studies

    The relationship between seminal leukocytes, oxidative status in the ejaculate, and apoptotic markers in human spermatozoa

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    The aim of this study was to investigate the relationship between seminal leukocytes, reactive oxygen species (ROS) production in the ejaculate, and markers of apoptosis in human spermatozoa. Semen samples were collected from 60 patients attending fertility clinics at the Reproductive Biology Unit at Tygerberg Academic Hospital and Vincent Pallotti Hospital, Cape Town, South Africa. The concentration of seminal leukocytes was determined and was correlated with ROS production in the ejaculate, the percentage of superoxide (·O2 )- and hydrogen peroxide (H2O2)-positive spermatozoa, glutathione activation in the ejaculate, and with markers of apoptosis in spermatozoa, namely cysteine-dependent aspartate-directed proteases (caspase)-3/7 activation, mitochondrial membrane potential (ΔΨm), and the percentage of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL)-positive sperm. Significant correlations with the concentration of seminal leukocytes were found for ROS production in the ejaculate, the percentage of ·O2 -positive spermatozoa, and caspase-3/7 activation in the ejaculate. Leukocytospermic samples showed significantly higher ROS production, percentage of ·O2 -positive sperm, GSH activation, and caspase-3/7 activation compared to non-leukocytospermic samples. The percentage of ·O2 -positive sperm was significantly correlated with sperm ΔΨm and caspase-3/7 activation in the ejaculate. Sperm ΔΨm and TUNEL-positive sperm did not correlate with seminal leukocyte concentration. Data demonstrate that high seminal leukocyte concentrations that leads to increased seminal ROS production, and is also associated with caspase activation in the male germ cell and increased mitochondrial ROS production. The latter could possibly be a result of disturbed ΔΨm. The activation of caspase-3/7 could then follow the increased intrinsic superoxide levels due to depleted intrinsic glutathione (GSH). These cellular events might not directly and immediately lead to DNA fragmentation as an endpoint of apoptosis because of topological hindrances.Web of Scienc

    Peripersonal space representation develops independently from visual experience

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    Our daily-life actions are typically driven by vision. When acting upon an object, we need to represent its visual features (e.g. shape, orientation, etc.) and to map them into our own peripersonal space. But what happens with people who have never had any visual experience? How can they map object features into their own peripersonal space? Do they do it differently from sighted agents? To tackle these questions, we carried out a series of behavioral experiments in sighted and congenitally blind subjects. We took advantage of a spatial alignment effect paradigm, which typically refers to a decrease of reaction times when subjects perform an action (e.g., a reach-To-grasp pantomime) congruent with that afforded by a presented object. To systematically examine peripersonal space mapping, we presented visual or auditory affording objects both within and outside subjects' reach. The results showed that sighted and congenitally blind subjects did not differ in mapping objects into their own peripersonal space. Strikingly, this mapping occurred also when objects were presented outside subjects' reach, but within the peripersonal space of another agent. This suggests that (the lack of) visual experience does not significantly affect the development of both one's own and others' peripersonal space representation

    Mouse Cognition-Related Behavior in the Open-Field: Emergence of Places of Attraction

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    Spatial memory is often studied in the Morris Water Maze, where the animal's spatial orientation has been shown to be mainly shaped by distal visual cues. Cognition-related behavior has also been described along “well-trodden paths”—spatial habits established by animals in the wild and in captivity reflecting a form of spatial memory. In the present study we combine the study of Open Field behavior with the study of behavior on well-trodden paths, revealing a form of locational memory that appears to correlate with spatial memory. The tracked path of the mouse is used to examine the dynamics of visiting behavior to locations. A visit is defined as either progressing through a location or stopping there, where progressing and stopping are computationally defined. We then estimate the probability of stopping at a location as a function of the number of previous visits to that location, i.e., we measure the effect of visiting history to a location on stopping in it. This can be regarded as an estimate of the familiarity of the mouse with locations. The recently wild-derived inbred strain CZECHII shows the highest effect of visiting history on stopping, C57 inbred mice show a lower effect, and DBA mice show no effect. We employ a rarely used, bottom-to-top computational approach, starting from simple kinematics of movement and gradually building our way up until we end with (emergent) locational memory. The effect of visiting history to a location on stopping in it can be regarded as an estimate of the familiarity of the mouse with locations, implying memory of these locations. We show that the magnitude of this estimate is strain-specific, implying a genetic influence. The dynamics of this process reveal that locations along the mouse's trodden path gradually become places of attraction, where the mouse stops habitually

    The haptic perception of spatial orientations

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    This review examines the isotropy of the perception of spatial orientations in the haptic system. It shows the existence of an oblique effect (i.e., a better perception of vertical and horizontal orientations than oblique orientations) in a spatial plane intrinsic to the haptic system, determined by the gravitational cues and the cognitive resources and defined in a subjective frame of reference. Similar results are observed from infancy to adulthood. In 3D space, the haptic processing of orientations is also anisotropic and seems to use both egocentric and allocentric cues. Taken together, these results revealed that the haptic oblique effect occurs when the sensory motor traces associated with exploratory movement are represented more abstractly at a cognitive level

    Rubber Hands Feel Touch, but Not in Blind Individuals

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    Psychology and neuroscience have a long-standing tradition of studying blind individuals to investigate how visual experience shapes perception of the external world. Here, we study how blind people experience their own body by exposing them to a multisensory body illusion: the somatic rubber hand illusion. In this illusion, healthy blindfolded participants experience that they are touching their own right hand with their left index finger, when in fact they are touching a rubber hand with their left index finger while the experimenter touches their right hand in a synchronized manner (Ehrsson et al. 2005). We compared the strength of this illusion in a group of blind individuals (n = 10), all of whom had experienced severe visual impairment or complete blindness from birth, and a group of age-matched blindfolded sighted participants (n = 12). The illusion was quantified subjectively using questionnaires and behaviorally by asking participants to point to the felt location of the right hand. The results showed that the sighted participants experienced a strong illusion, whereas the blind participants experienced no illusion at all, a difference that was evident in both tests employed. A further experiment testing the participants' basic ability to localize the right hand in space without vision (proprioception) revealed no difference between the two groups. Taken together, these results suggest that blind individuals with impaired visual development have a more veridical percept of self-touch and a less flexible and dynamic representation of their own body in space compared to sighted individuals. We speculate that the multisensory brain systems that re-map somatosensory signals onto external reference frames are less developed in blind individuals and therefore do not allow efficient fusion of tactile and proprioceptive signals from the two upper limbs into a single illusory experience of self-touch as in sighted individuals

    Architecture, Space and Information in Constructions Built by Humans and Social Insects: a Conceptual Review

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    The similarities between the structures built by social insects and by humans have led to a convergence of interests between biologists and architects. This new, de facto interdisciplinary community of scholars needs a common terminology and theoretical framework in which to ground its work. In this conceptually oriented review paper, we review the terms “information”, “space” and “architecture” to provide definitions that span biology and architecture. A framework is proposed on which interdisciplinary exchange may be better served, with the view that this will aid better cross fertilisation between disciplines, working in the areas of collective behaviour and analysis of the structures and edifices constructed by non-humans; and to facilitate how this area of study may better contribute to the field of architecture. We then use these definitions to discuss the informational content of constructions built by organisms and the influence these have on behaviour, and vice versa. We review how spatial constraints inform and influence interaction between an organism and its environment, and examine the reciprocity of space and information on construction and the behaviour of humans and social insects
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