7,718 research outputs found

    Evaluation of Packed Towers for Removing Volatile Organics from Surface Waters

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    This study analyzes the potential of packed tower aeration as a remedial treatment process for the removal of trace organics on either an acute or chronic basis. Both pilot-scale installations of the packed tower process were reviewed. Included are basic modeling considerations for the removal of volatile trace organics from raw water. Included also is an assessment of the state of the technology as applied to air stripping of water

    Attribution of intentional causation influences the perception of observed movements: behavioral evidence and neural correlates

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    Recent research on human agency suggests that intentional causation is associated with a subjective compression in the temporal interval between actions and their effects. That is, intentional movements and their causal effects are perceived as closer together in time than equivalent unintentional movements and their causal effects. This so-called intentional binding effect is consistently found for one's own self-generated actions. It has also been suggested that intentional binding occurs when observing intentional movements of others. However, this evidence is undermined by limitations of the paradigm used. In the current study we aimed to overcome these limitations using a more rigorous design in combination with functional Magnetic Resonance Imaging (fMRI) to explore the neural underpinnings of intentional binding of observed movements. In particular, we aimed to identify brain areas sensitive to the interaction between intentionality and causality attributed to the observed action. Our behavioral results confirmed the occurrence of intentional binding for observed movements using this more rigorous paradigm. Our fMRI results highlighted a collection of brain regions whose activity was sensitive to the interaction between intentionality and causation. Intriguingly, these brain regions have previously been implicated in the sense of agency over one's own movements. We discuss the implications of these results for intentional binding specifically, and the sense of agency more generally

    The Health Care Consequences of Smoking and its Regulation

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    The literature on the health economics of smoking presents two principal facts: that smoking increases health care costs, and that restrictions on smoking lead to reductions in smoking prevalence and intensity. Some researchers have hypothesized that these two facts, in combination, allow the inference that restricting smoking will lower health care costs. For a variety of reasons, however, observed associations between smoking and health care use on the one hand, and regulations and smoking on the other, do not imply a casual effect of the restrictions on health care. This paper extends the literature by examining whether cigarette tax increases lead to lower health care costs. Using data from the 1991 and 1993 National Heath Interview Surveys, it first reproduces the principal results in the literature on smoking, taxes, and health care utilization, and then estimates the effects of tobacco taxes on health care. The results indicate that once one controls for endogenous quits, the health care benefits of smoking cessation are greater than previously believed. There is weak evidence that tax increases lead to higher cessation rates. In combination, these results suggest that, in addition providing a source for funding excess health care costs, tax increases may lower health care costs (for given longevity) directly by inducing smokers to quit.

    Sense of agency, associative learning, and schizotypy

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    Despite the fact that the role of learning is recognised in empirical and theoretical work on sense of agency (SoA), the nature of this learning has, rather surprisingly, received little attention. In the present study we consider the contribution of associative mechanisms to SoA. SoA can be measured quantitatively as a temporal linkage between voluntary actions and their external effects. Using an outcome blocking procedure, it was shown that training action-outcome associations under conditions of increased surprise augmented this temporal linkage. Moreover, these effects of surprise were correlated with schizotypy scores, suggesting that individual differences in higher level experiences are related to associative learning and to its impact on SoA. These results are discussed in terms of models of SoA, and our understanding of disrupted SoA in certain disorders

    Development of a Smart Release Algorithm for Mid-Air Separation of Parachute Test Articles

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    The Crew Exploration Vehicle Parachute Assembly System (CPAS) project is currently developing an autonomous method to separate a capsule-shaped parachute test vehicle from an air-drop platform for use in the test program to develop and validate the parachute system for the Orion spacecraft. The CPAS project seeks to perform air-drop tests of an Orion-like boilerplate capsule. Delivery of the boilerplate capsule to the test condition has proven to be a critical and complicated task. In the current concept, the boilerplate vehicle is extracted from an aircraft on top of a Type V pallet and then separated from the pallet in mid-air. The attitude of the vehicles at separation is critical to avoiding re-contact and successfully deploying the boilerplate into a heatshield-down orientation. Neither the pallet nor the boilerplate has an active control system. However, the attitude of the mated vehicle as a function of time is somewhat predictable. CPAS engineers have designed an avionics system to monitor the attitude of the mated vehicle as it is extracted from the aircraft and command a release when the desired conditions are met. The algorithm includes contingency capabilities designed to release the test vehicle before undesirable orientations occur. The algorithm was verified with simulation and ground testing. The pre-flight development and testing is discussed and limitations of ground testing are noted. The CPAS project performed a series of three drop tests as a proof-of-concept of the release technique. These tests helped to refine the attitude instrumentation and software algorithm to be used on future tests. The drop tests are described in detail and the evolution of the release system with each test is described

    A Hybrid Parachute Simulation Environment for the Orion Parachute Development Project

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    A parachute simulation environment (PSE) has been developed that aims to take advantage of legacy parachute simulation codes and modern object-oriented programming techniques. This hybrid simulation environment provides the parachute analyst with a natural and intuitive way to construct simulation tasks while preserving the pedigree and authority of established parachute simulations. NASA currently employs four simulation tools for developing and analyzing air-drop tests performed by the CEV Parachute Assembly System (CPAS) Project. These tools were developed at different times, in different languages, and with different capabilities in mind. As a result, each tool has a distinct interface and set of inputs and outputs. However, regardless of the simulation code that is most appropriate for the type of test, engineers typically perform similar tasks for each drop test such as prediction of loads, assessment of altitude, and sequencing of disreefs or cut-aways. An object-oriented approach to simulation configuration allows the analyst to choose models of real physical test articles (parachutes, vehicles, etc.) and sequence them to achieve the desired test conditions. Once configured, these objects are translated into traditional input lists and processed by the legacy simulation codes. This approach minimizes the number of sim inputs that the engineer must track while configuring an input file. An object oriented approach to simulation output allows a common set of post-processing functions to perform routine tasks such as plotting and timeline generation with minimal sensitivity to the simulation that generated the data. Flight test data may also be translated into the common output class to simplify test reconstruction and analysis

    “They Were Noble Automatons Who Knew Not What They Did:” Volition in Jaynes' The Origin of Consciousness in the Breakdown of the Bicameral Mind

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    An important question in consciousness research concerns its origins. In Julian Jaynes’ book, The Origin of Consciousness in the Breakdown of the Bicameral Mind, he suggests that consciousness arose rather recently in human history, sometime between the composition of The Iliad and The Odyssey. Although Jaynes’ work as a theory of consciousness has achieved a great deal of attention (and indeed criticism), what has not been widely noted is the prominent role of volition in his theory. In this article I hope to draw attention to these overlooked aspects of his theory, in particular the fact that volition is central to Jaynes’ definition of consciousness and that it is changes in the nature of volitional experience that mark, for Jaynes, the emergence of consciousnes
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