2,507 research outputs found

    Can Multi-Regional Trajectory Based Operations Reduce Workload-Related Aviation Incidents?

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    Multi-Regional Trajectory Based Operations (MR TBO) was developed by Florida NextGen Test Bed (FTB) along with the Federal Aviation Administration (FAA) as a method for enhancing air traffic management (ATM), both domestically and internationally. TBO offers a shift from voice-based exchanges between Air Traffic Controllers and pilots to highly automated, digital communication exchanges. The purpose of this poster is twofold. First, it explains how TBO can help improve route amendments, speed change, strategic handling of ground events, and sharing and managing multiple aircraft. Second, the poster proposes the integration of MR TBO into the National Airspace System (NAS) to decrease the number of incidents caused by high workloads of ATM. Results of this poster suggest that the operational value of adopting MR TBO extends towards the airlines, pilots, and air traffic controllers. A resulting increase of efficiency and safety will revolutionize the NAS for future generations of the aviation industry

    Spatial and temporal variation of rod photoreceptor reflectance in the human retina

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    Using adaptive optics imaging tools to image the living retina, numerous investigators have reported temporal fluctuation in the reflectivity of individual cone photoreceptors. In addition, there is cone-to-cone (spatial) variation in reflectivity. As it has only recently become possible to image the complete rod photoreceptor mosaic in the living human retina, we sought to characterize the reflectivity of individual rods and compare their behavior to that of foveal/parafoveal cones. Across two subjects, we were able to successfully track the reflectance behavior of 1,690 rods and 1,980 cones over 12 hours. Rod and cone photoreceptors showed similar regional and temporal variability in their reflectance profiles, suggesting the presence of a common governing physiological process. Within the rod and cone mosaics, there was no sign of spatial clumping of reflectance profile behavior; that is, the arrangement of cells of a given archetypal reflectance profile within the mosaic was indistinguishable from random. These data demonstrate the ability to track the behavior of rod reflectivity over time. Finally, as these and other reflectance changes may be an indicator of photoreceptor function, a future extension of this method will be to analyze this behavior in patients with rod photoreceptor dysfunction (e.g., retinitis pigmentosa, Usher’s syndrome, and congenital stationary night blindness)

    Conceptual learning : the priority for higher education

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    The common sense notion of learning as the all-pervasive acquisition of new behaviour and knowledge, made vivid by experience, is an incomplete characterisation, because it assumes that the learning of behaviour and the learning of knowledge are indistinguishable, and that acquisition constitutes learning without reference to transfer. A psychological level of analysis is used to argue that conceptual learning should have priority in higher education

    Identification of Stipules reduced, a leaf morphology gene in pea (Pisum sativum)

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    Pea (Pisum sativum) is one of relatively few genetically amenable plant species with compound leaves. Pea leaves have a variety of specialized organs: leaflets, tendrils, pulvini and stipules, which enable the identification of mutations that transform or affect distinct parts of the leaf. Characterization of these mutations offers insights into the development and evolution of novel leaf traits. The previously characterized morphological gene Cochleata, conferring stipule identity, was known to interact with Stipules reduced (St), which conditions stipule size in pea, but the St gene remained unknown. Here we analysed Fast Neutron irradiated pea mutants by restriction site associated DNA sequencing. We identified St as a gene encoding a C2H2 zinc finger transcription factor that is regulated by Cochleata. St regulates both cell division and cell expansion in the stipule. Our approach shows how systematic genome-wide screens can be used successfully for the analysis of traits in species for which whole genome sequences are not available

    Invariant template matching in systems with spatiotemporal coding: a vote for instability

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    We consider the design of a pattern recognition that matches templates to images, both of which are spatially sampled and encoded as temporal sequences. The image is subject to a combination of various perturbations. These include ones that can be modeled as parameterized uncertainties such as image blur, luminance, translation, and rotation as well as unmodeled ones. Biological and neural systems require that these perturbations be processed through a minimal number of channels by simple adaptation mechanisms. We found that the most suitable mathematical framework to meet this requirement is that of weakly attracting sets. This framework provides us with a normative and unifying solution to the pattern recognition problem. We analyze the consequences of its explicit implementation in neural systems. Several properties inherent to the systems designed in accordance with our normative mathematical argument coincide with known empirical facts. This is illustrated in mental rotation, visual search and blur/intensity adaptation. We demonstrate how our results can be applied to a range of practical problems in template matching and pattern recognition.Comment: 52 pages, 12 figure

    An Integrated Imaging Approach to the Study of Oxidative Stress Generation by Mitochondrial Dysfunction in Living Cells

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    BACKGROUND: The mechanisms of action of many environmental agents commonly involve oxidative stress resulting from mitochondrial dysfunction. Zinc is a common environmental metallic contaminant that has been implicated in a variety of oxidant-dependent toxicological responses. Unlike ions of other transition metals such as iron, copper, and vanadium, Zn(2+) does not generate reactive oxygen species (ROS) through redox cycling. OBJECTIVE: To characterize the role of oxidative stress in zinc-induced toxicity. METHODS: We used an integrated imaging approach that employs the hydrogen peroxide (H2O2)-specific fluorophore Peroxy Green 1 (PG1), the mitochondrial potential sensor 5,5 ,6,6 -tetrachloro-1,1 ,3,3 -tetraethylbenzimidazolylcarbocyanine iodide (JC-1), and the mitochondria-targeted form of the redox-sensitive genetically encoded fluorophore MTroGFP1 in living cells. RESULTS: Zinc treatment in the presence of the Zn(2+) ionophore pyrithione of A431 skin carcinoma cells preloaded with the H(2)O(2)-specific indicator PG1 resulted in a significant increase in H(2)O(2) production that could be significantly inhibited with the mitochondrial inhibitor carbonyl cyanide 3-chlorophenylhydrazone. Mitochondria were further implicated as the source of zinc-induced H(2)O(2) formation by the observation that exposure to zinc caused a loss of mitochondrial membrane potential. Using MTroGFP1, we showed that zinc exposure of A431 cells induces a rapid loss of reducing redox potential in mitochondria. We also demonstrated that zinc exposure results in rapid swelling of mitochondria isolated from mouse hearts. CONCLUSION: Taken together, these findings show a disruption of mitochondrial integrity, H(2)O(2) formation, and a shift toward positive redox potential in cells exposed to zinc. These data demonstrate the utility of real-time, live-cell imaging to study the role of oxidative stress in toxicological responses

    Meaning, Truth, and Physics

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    A physical theory is a partially interpreted axiomatic formal system (L,S), where L is a formal language with some logical, mathematical and physical axioms, and with some derivation rules, and the semantics S is a relationship between the formulas of L and some states of affairs in the physical world. In our ordinary discourse, the formal system L is regarded as an abstract object or structure, the semantics S as something which involves the mental/conceptual realm. This view is of course incompatible with physicalism. How can physical theory be accommodated in a purely physical ontology? The aim of this paper is to outline an account for meaning and truth of physical theory, within the philosophical framework spanned by three doctrines: physicalism, empiricism, and the formalist philosophy of mathematics

    The attachment system and physiology in adulthood: normative processes, individual differences, and implications for health.

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    Attachment theory provides a conceptual framework for understanding intersections between personality and close relationships in adulthood. Moreover, attachment has implications for stress-related physiology and physical health. We review work on normative processes and individual differences in the attachment behavioral system, as well as their associations with biological mechanisms related to health outcomes. We highlight the need for more basic research on normative processes and physiology and discuss our own research on individual differences in attachment and links with physiology. We then describe a novel perspective on attachment and physiology, wherein stress-related physiological changes may also be viewed as supporting the social-cognitive and emotion regulatory functions of the attachment system through providing additional energy to the brain, which has implications for eating behavior and health. We close by discussing our work on individual differences in attachment and restorative processes, including sleep and skin repair, and by stressing the importance of developing biologically plausible models for describing how attachment may impact chronic illness
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