13,793 research outputs found
Aircraft remote sensing of phytoplankton spatial patterns during the 1989 Joint Global Ocean Flux Study (JGOFS) North Atlantic bloom experiment
Mesoscale phytoplankton chlorophyll variability near the Joint Global Ocean Flux study sites along the 20 W meridian at 34 N, 47 N, and 59 N is discussed. The NASA P-3 aircraft and the Airborne Oceanographic Lidar (AOL) system provides remote sensing support for the North Atlantic Bloom Experiment. The principal instrument of the AOL system is the blue-green laser that stimulates fluorescence from photoplankton chlorophyll, the principal photosynthetic pigment. Other instruments on the NASA P-3 aircraft include up- and down-looking spectrometers, PRT-5 for infrared measurements to determine sea surface temperature, and a system to deploy and record AXBTs to measure subsurface temperature structure
Autoplan: A self-processing network model for an extended blocks world planning environment
Self-processing network models (neural/connectionist models, marker passing/message passing networks, etc.) are currently undergoing intense investigation for a variety of information processing applications. These models are potentially very powerful in that they support a large amount of explicit parallel processing, and they cleanly integrate high level and low level information processing. However they are currently limited by a lack of understanding of how to apply them effectively in many application areas. The formulation of self-processing network methods for dynamic, reactive planning is studied. The long-term goal is to formulate robust, computationally effective information processing methods for the distributed control of semiautonomous exploration systems, e.g., the Mars Rover. The current research effort is focusing on hierarchical plan generation, execution and revision through local operations in an extended blocks world environment. This scenario involves many challenging features that would be encountered in a real planning and control environment: multiple simultaneous goals, parallel as well as sequential action execution, action sequencing determined not only by goals and their interactions but also by limited resources (e.g., three tasks, two acting agents), need to interpret unanticipated events and react appropriately through replanning, etc
Adaptive stepsize and instabilities in complex Langevin dynamics
Stochastic quantization offers the opportunity to simulate field theories
with a complex action. In some theories unstable trajectories are prevalent
when a constant stepsize is employed. We construct algorithms for generating an
adaptive stepsize in complex Langevin simulations and find that unstable
trajectories are completely eliminated. To illustrate the generality of the
approach, we apply it to the three-dimensional XY model at nonzero chemical
potential and the heavy dense limit of QCD.Comment: 12 pages, several eps figures; clarification and minor corrections
added, to appear in PL
Deregulation of conveyancing markets in England and Wales
There has been much concern in recent years with whether the âprivilegeâ of self- regulation accorded to the professions works for or against the public interest (Federal Trade Commission, 1984; Monopolies and Mergers Commission, 1970, 1976a and 1976b; Department of Trade and Industry, 1989; Courts and Legal Services Act, 1990). Ogus (1993) argues that âSelf-regulation has had a bad pressâ and that âmost of this criticism is well-founded in relation to some forms of self- regulationâ. Economists have been, traditionally, highly critical of many aspects of professional self-regulation.2 More recently, there has been a greater awareness of the informational asymmetry inherent in professional markets which demands some protection for the (infrequent) consumer of personal professional services (see, for example, Dingwall and Fenn (1987)). Commentators have identified three principal instruments of such selfregulators which work against the public interest: (1) restrictions on entry; (2) restrictions on fee competition; and (3) restrictions on advertising and other means of promoting a competitive process within the profession.
Science review: Mechanisms of ventilator-induced injury
Acute respiratory distress syndrome (ARDS) and acute lung injury are among the most frequent reasons for intensive care unit admission, accounting for approximately one-third of admissions. Mortality from ARDS has been estimated as high as 70% in some studies. Until recently, however, no targeted therapy had been found to improve patient outcome, including mortality. With the completion of the National Institutes of Health-sponsored Acute Respiratory Distress Syndrome Network low tidal volume study, clinicians now have convincing evidence that ventilation with tidal volumes lower than those conventionally used in this patient population reduces the relative risk of mortality by 21%. These data confirm the long-held suspicion that the role of mechanical ventilation for acute hypoxemic respiratory failure is more than supportive, in that mechanical ventilation can also actively contribute to lung injury. The mechanisms of the protective effects of low tidal volume ventilation in conjunction with positive end expiratory pressure are incompletely understood and are the focus of ongoing studies. The objective of the present article is to review the potential cellular mechanisms of lung injury attributable to mechanical ventilation in patients with ARDS and acute lung injury
Detectives and The Legal System: A Paradigm to Support Scholarly Inquiry and Mixed Methods Research in the Social Sciences
It is argued in this article that the legal system, from initial investigation by detectives to final resolution in court by lawyers, judges, and juries, offers a basis for investigating phenomena in the social sciences using mixed methods. We think that this new paradigm combines the components of both the qualitative and quantitative paradigms and provides a practical model for conceptualizing and conducting mixed methods research. The implication of this new paradigm is that it may help us better understand underlying phenomena in scholarly inquiry and thus offers a potential contribution for using a mixed-methods approach in both education and the social sciences. However, adopting and adapting this paradigm for mixed-methods inquiry will require further exploration and empirical replication
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