414 research outputs found

    Evaluation of insulation materials and composites for use in a nuclear radiation environment, phase 2

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    The nuclear heating of the propellant in all of the four baseline RNS configurations studied was much lower than that of the nuclear flight module configuration with the 5000-MW NERVA analyzed previously. Although the nuclear heating has been reduced, the effect of nuclear heating on the propellant as well as the effect of nuclear heating on internal structures such as antivortex baffles, screens, and sump components cannot be neglected. In addition, it was found that the present analytical precedures were not able to predict boundary layer initiation and breakoff points with the accuracy necessary to predict propellant thermodynamic nonequilibrium (stratification) and/or mixing

    Computer automation of ultrasonic testing

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    Report describes a prototype computer-automated ultrasonic system developed for the inspection of weldments. This system can be operated in three modes: manual, automatic, and computer-controlled. In the computer-controlled mode, the system will automatically acquire, process, analyze, store, and display ultrasonic inspection data in real-time. Flaw size (in cross-section), location (depth), and type (porosity-like or crack-like) can be automatically discerned and displayed. The results and pertinent parameters are recorded

    Μελέτη επιπτώσεων συνδρομολόγησηςεφαρμογών σε πολυπύρηνες αρχιτεκτονικές

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    Understanding viral transmission dynamics within populations of reservoir hosts can facilitate greater knowledge of the spillover of emerging infectious diseases. While bat-borne viruses are of concern to public health, investigations into their dynamics have been limited by a lack of longitudinal data from individual bats. Here, we examine capture-mark-recapture (CMR) data from a species of Australian bat (Myotis macropus) infected with a putative novel Alphacoronavirus within a Bayesian framework. Then, we developed epidemic models to estimate the effect of persistently infectious individuals (which shed viruses for extensive periods) on the probability of viral maintenance within the study population. We found that the CMR data analysis supported grouping of infectious bats into persistently and transiently infectious bats. Maintenance of coronavirus within the study population was more likely in an epidemic model that included both persistently and transiently infectious bats, compared with the epidemic model with non-grouping of bats. These findings, using rare CMR data from longitudinal samples of individual bats, increase our understanding of transmission dynamics of bat viral infectious diseases

    AI in Production: Video Analysis and Machine Learning for Expanded Live Events Coverage

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    In common with many industries, TV and video production is likely to be transformed by Artificial Intelligence (AI) and Machine Learning (ML), with software and algorithms assisting production tasks that, conventionally, could only be carried out by people. Expanded coverage of a diverse range of live events is particularly constrained by the relative scarcity of skilled people, and is a strong use case for AI-based automation. This paper describes recent BBC research into potential production benefits of AI algorithms, using visual analysis and other techniques. Rigging small, static UHD cameras, we have enabled a one-person crew to crop UHD footage in multiple ways and cut between the resulting shots, effectively creating multi-camera HD coverage of events that cannot accommodate a camera crew. By working with programme makers to develop simple deterministic rules and, increasingly, training systems using advanced video analysis, we are developing a system of algorithms to automatically frame, sequence and select shots, and construct acceptable multicamera coverage of previously untelevised types of event

    An unusual cause of alveolar hemorrhage post hematopoietic stem cell transplantation: A case report

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    BACKGROUND: Hematopoietic stem cell transplantation is being increasingly used in cancer therapy. Diffuse alveolar hemorrhage, an early complication of stem cell transplant, results from bacterial, viral and fungal infections, coagulopathy, and engraftment syndrome, or can be idiopathic. Diffuse alveolar hemorrhage associated with Strongyloides stercoralis hyperinfection in stem cell transplant patients has been rarely reported. CASE PRESENTATION: We describe an unusual cause of alveolar hemorrhage post hematopoietic stem cell transplant due to Strongyloides hyperinfection. Therapy with parenteral ivermectin and thiabendazole was initiated but the patient deteriorated and died of respiratory failure and septic shock. CONCLUSION: Strongyloides stercoralis hyperinfection is an unusual cause of alveolar hemorrhage early after hematopoietic stem cell transplant with very high mortality

    An exploratory study on the potential of social enterprise to act as the institutional glue of network governance

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    This study combines two topics of contemporary salience for public administration: social enterprise and governance networks. While operating at different levels, both are institutions which attempt to draw together the three pillars of state, market, and civil society. Nevertheless, the respective literatures focus on particular aspects of the three pillars. We connect the two concepts and suggest that some social enterprises can act as the institutional glue of networks due to their ability to benefit organizations in each of the three sectors. This requires social enterprises to have the managerial capacity to diffuse social know-how, and is facilitated by the trust of other organizations and a supportive policy framework. The links are explicated at the conceptual level before providing evidence from South Korea and the UK. Finally, research propositions are offered, which suggest new avenues for future research

    Light modulated cnidocyte discharge predates the origins of eyes in Cnidaria

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    Complex biological traits often originate by integrating previously separate parts, but the organismal functions of these precursors are challenging to infer. If we can understand the ancestral functions of these precursors, it could help explain how they persisted and how they facilitated the origins of complex traits. Animal eyes are some of the best studied complex traits, and they include many parts, such as opsin-based photoreceptor cells, pigment cells, and lens cells. Eye evolution is understood through conceptual models that argue these parts gradually came together to support increasingly sophisticated visual functions. Despite the well-accepted logic of these conceptual models, explicit comparative studies to identify organismal functions of eye precursors are lacking. Here, we investigate how precursors functioned before they became part of eyes in Cnidaria, a group formed by sea anemones, corals, and jellyfish. Specifically, we test whether ancestral photoreceptor cells regulated the discharge of cnidocytes, the expensive single-use cells with various functions including prey capture, locomotion, and protection. Similar to a previous study of Hydra, we show an additional four distantly related cnidarian groups discharge significantly more cnidocytes when exposed to dim blue light compared with bright blue light. Our comparative analyses support the hypothesis that the cnidarian ancestor was capable of modulating cnidocyte discharge with light, which we speculate uses an opsin-based phototransduction pathway homologous to that previously described in Hydra. Although eye precursors might have had other functions like regulating timing of spawning, our findings are consistent with the hypothesis that photoreceptor cells which mediate cnidocyte discharge predated eyes, perhaps facilitating the prolific origination of eyes in Cnidaria

    Together forever? Explaining exclusivity in party-firm relations

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    Parties and firms are the key actors of representative democracy and capitalism respectively and the dynamic of attachment between them is a central feature of any political economy. This is the first article to systematically analyse the exclusivity of party-firm relations. We consider exclusivity at a point in time and exclusivity over time. Does a firm have a relationship with only one party at a given point in time, or is it close to more than one party? Does a firm maintain a relationship with only one party over time, or does it switch between parties? Most important, how do patterns of exclusivity impact on a firm’s ability to lobby successfully? We propose a general theory, which explains patterns of party-firm relations by reference to the division of institutions and the type of party competition in a political system. A preliminary test of our theory with Polish survey data confirms our predictions, establishing a promising hypothesis for future research
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