307 research outputs found
BCAUS Project description and consideration of separation of data and control
The commonly stated truths that data may be segregated from program control in generic expert system shells and that such tools support straightforward knowledge representation were examined. The ideal of separation of data from program control in expert systems is difficult to realize for a variety of reasons. One approach to achieving this goal is to integrate hybrid collections of specialized shells and tools instead of producing custom systems built with a single all purpose expert system tool. Aspects of these issues are examined in the context of a specific diagnostic expert system application, the Backup Control Mode Analysis and Utility System (BCAUS), being developed for the Gamma Ray Observatory (GRO) spacecraft. The project and the knowledge gained in working on the project are described
Labor Productivity in Sawmills of the Eastern and Southeastern United States
A survey of sawmills in the eastern and southeastern regions of the United States was conducted. Responding mills produced an average of 12,661 MBf in calendar year 1984 and 76 percent reported annual sales of less than $10 million. The majority of sawmills utilized circular saw headrigs and the most common type of computer controlled/assisted equipment was a log carriage. Softwood sawmills were found to have significantly higher labor productivity than hardwood sawmills. Regression analysis indicated that labor productivity economies of scale exist within the softwood segment of the industry. Labor productivity increased with mill size but at a decreasing rate. No strong evidence of labor productivity economies of scale in the hardwood industry segment was found
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The effect of increased convective entrainment on Asian monsoon biases in the MetUM General Circulation Model
We demonstrate that summer precipitation biases in the South Asian monsoon domain are sensitive to increasing the convective parametrisationās entrainment and detrainment rates in the Met Ofļ¬ce Uniļ¬ed Model. We explore this sensitivity to improve our understanding of the biases and inform efforts to improve convective parametrisation. We perform novel targeted experiments in which we increase the entrainment and detrainment rates in regions of especially large precipitation bias. We use these experiments to determine whether the sensitivity at a given location is a consequence of the local change to convection or is a remote response to the change elsewhere. We ļ¬nd that a local change leads to different mean-state responses in comparable regions. When the entrainment and detrainment rates are increased globally, feedbacks between regions usually strengthen the local responses. We choose two regions of tropical ascent that show different mean-state responses, the western equatorial Indian Ocean and western north Paciļ¬c, and analyse them as case studies to determine
the mechanisms leading to the different responses. Our results indicate that several aspects of a regionās mean-state, including moisture content, sea surface temperature and circulation, play a role in local feedbacks that determine the response to increased entrainment and detrainment
How to Block Cartel Formation and Price-Fixing
Abstract written by the AEI-Brookings Joint Center: Allowing foreign buyers of goods produced by international cartels to pursue civil antitrust damages in U.S. courts would better deter cartel formation and price-fixing than do sanctions currently imposed by global criminal and civil justice systems.Technology and Industry, Regulatory Reform, Other Topics
BUMPER v1.0: a Bayesian user-friendly model for palaeo-environmental reconstruction
We describe the Bayesian user-friendly model for palaeo-environmental reconstruction (BUMPER), a Bayesian transfer function for inferring past climate and other environmental variables from microfossil assemblages. BUMPER is fully self-calibrating, straightforward to apply, and computationally fast, requiring ~2 s to build a 100-taxon model from a 100-site training set on a standard personal computer. We apply the modelās probabilistic framework to generate thousands of artificial training sets under ideal assumptions.We then use these to demonstrate the sensitivity of reconstructions to the characteristics of the training set, considering assemblage richness, taxon tolerances, and the number of training sites. We find that a useful guideline for the size of a training set is to provide, on average, at least 10 samples of each taxon. We demonstrate general applicability to real data, considering three different organism types (chironomids, diatoms, pollen) and different reconstructed variables. An identically configured model is used in each application, the only change being the input files that provide the training-set environment and taxon-count data. The performance of BUMPER is shown to be comparable with weighted average partial least squares (WAPLS) in each case. Additional artificial datasets are constructed with similar characteristics to the real data, and these are used to explore the reasons for the differing performances of the different training sets
Convergence towards a European strategic culture? A constructivist framework for explaining changing norms.
The article contributes to the debate about the emergence of a European strategic culture to underpin a European Security and Defence Policy. Noting both conceptual and empirical weaknesses in the literature, the article disaggregates the concept of strategic culture and focuses on four types of norms concerning the means and ends for the use of force. The study argues that national strategic cultures are less resistant to change than commonly thought and that they have been subject to three types of learning pressures since 1989: changing threat perceptions, institutional socialization, and mediatized crisis learning. The combined effect of these mechanisms would be a process of convergence with regard to strategic norms prevalent in current EU countries. If the outlined hypotheses can be substantiated by further research the implications for ESDP are positive, especially if the EU acts cautiously in those cases which involve norms that are not yet sufficiently shared across countries
A Petal of the Sunflower: Photometry of the Stellar Tidal Stream in the Halo of Messier 63 (NGC 5055)
We present surface photometry of a very faint, giant arc feature in the halo
of the nearby spiral galaxy NGC 5055 (M63) that is consistent with being a part
of a stellar stream resulting from the disruption of a dwarf satellite galaxy.
This faint feature was first detected in early photographic studies by van der
Kruit (1979); more recently by Mart\'inez-Delgado et al. (2010) and as
presented in this work, the loop has been realized to be the result of a recent
minor merger through evidence obtained by deep images taken with a telescope of
only 0.16 m aperture. The stellar stream is confirmed in additional images
taken with the 0.5 m of the BlackBird Remote Observatory and the 0.8 m of the
McDonald Observatory. This low surface brightness structure around the disk of
the galaxy extends ~29 kpc from its center, with a projected width of 3.3 kpc.
The stream's morphology is consistent with that of the visible part of a
"great-circle" stellar stream originating from the accretion of a ~10^8 M_sun
dwarf satellite in the last few Gyr. The progenitor satellite's current
position and fate are not conclusive from our data. The color of the stream's
stars is consistent with Local Group dwarfs and is similar to the outer regions
of M63's disk and stellar halo. We detect other low surface brightness
"plumes"; some of these may be extended spiral features related to the galaxy's
complex spiral structure and others may be tidal debris associated with the
disruption of the galaxy's outer stellar disk as a result of the accretion
event. We differentiate between features related to the tidal stream and faint,
blue features in the outskirts of the galaxy's disk previously detected by the
GALEX satellite. With its highly warped HI gaseous disk (~20 deg), M63
represents one of several examples of an isolated spiral galaxy with a warped
disk showing strong evidence of an ongoing minor merger.Comment: 16 pages, 10 figures, 3 tables, Accepted for publication in The
Astronomical Journa
Comparison of F(ab') versus Fab antivenom for pit viper envenomation: A prospective, blinded, multicenter, randomized clinical trial
BACKGROUND:
Crotalidae Polyvalent Immune Fab (Ovine) has been the only antivenom commercially available in the US since 2007 for treatment of Crotalinae envenomation. Late coagulopathy can occur or recur after clearance of Fab antivenom, often after hospital discharge, lasting in some cases more than 2 weeks. There have been serious, even fatal, bleeding complications associated with recurrence phenomena. Frequent follow-up is required, and additional intervention or hospitalization is often necessary. F(ab')2 immunoglobulin derivatives have longer plasma half life than do Fab. We hypothesized that F(ab')2 antivenom would be superior to Fab in the prevention of late coagulopathy following treatment of patients with Crotalinae envenomation.
METHODS:
We conducted a prospective, double-blind, randomized clinical trial, comparing late coagulopathy in snakebitten patients treated with F(ab')2 with maintenance doses [F(ab')2/F(ab')2], or F(ab')2 with placebo maintenance doses [F(ab')2/placebo], versus Fab with maintenance doses [Fab/Fab]. The primary efficacy endpoint was coagulopathy (platelet count < 150 K/mm(3), fibrinogen level < 150 mg/dL) between end of maintenance dosing and day 8.
RESULTS:
121 patients were randomized at 18 clinical sites and received at least one dose of study drug. 114 completed the study. Of these, 11/37 (29.7%) in the Fab/Fab cohort experienced late coagulopathy versus 4/39 (10.3%, p < 0.05) in the F(ab')2/F(ab')2 cohort and 2/38 (5.3%, p < 0.05) in the F(ab')2/placebo cohort. The lowest heterologous protein exposure was with F(ab')2/placebo. No serious adverse events were related to study drug. In each study arm, one patient experienced an acute serum reaction and one experienced serum sickness.
CONCLUSIONS:
In this study, management of coagulopathic Crotalinae envenomation with longer-half-life F(ab')2 antivenom, with or without maintenance dosing, reduced the risk of subacute coagulopathy and bleeding following treatment of envenomation
Reduced Retinal Function in the Absence of Nav1.6
Background: Mice with a function-blocking mutation in the Scn8a gene that encodes Nav1.6, a voltage-gated sodium channel (VGSC) isoform normally found in several types of retinal neurons, have previously been found to display a profoundly abnormal dark adapted flash electroretinogram. However the retinal function of these mice in light adapted conditions has not been studied. Methodology/Principal Findings: In the present report we reveal that during light adaptation these animals are shown to have electroretinograms with significant decreases in the amplitude of the a- and b-waves. The percent decrease in the a-and b-waves substantially exceeds the acute effect of VGSC block by tetrodotoxin in control littermates. Intravitreal injection of CoCl 2 or CNQX to isolate the a-wave contributions of the photoreceptors in littermates revealed that at high background luminance the cone-isolated component of the a-wave is of the same amplitude as the a-wave of mutants. Conclusions/Significance: Our results indicate that Scn8a mutant mice have reduced function in both rod and the cone retinal pathways. The extent of the reduction in the cone pathway, as quantified using the ERG b-wave, exceeds the reduction seen in control littermates after application of TTX, suggesting that a defect in cone photoreceptors contributes to the reduction. Unless the postreceptoral component of the a-wave is increased in Scn8a mutant mice, the reduction in the b-wave is larger than can be accounted for by reduced photoreceptor function alone. Our data suggests that th
Unified treatment algorithm for the management of crotaline snakebite in the United States: results of an evidence-informed consensus workshop
<p>Abstract</p> <p>Background</p> <p>Envenomation by crotaline snakes (rattlesnake, cottonmouth, copperhead) is a complex, potentially lethal condition affecting thousands of people in the United States each year. Treatment of crotaline envenomation is not standardized, and significant variation in practice exists.</p> <p>Methods</p> <p>A geographically diverse panel of experts was convened for the purpose of deriving an evidence-informed unified treatment algorithm. Research staff analyzed the extant medical literature and performed targeted analyses of existing databases to inform specific clinical decisions. A trained external facilitator used modified Delphi and structured consensus methodology to achieve consensus on the final treatment algorithm.</p> <p>Results</p> <p>A unified treatment algorithm was produced and endorsed by all nine expert panel members. This algorithm provides guidance about clinical and laboratory observations, indications for and dosing of antivenom, adjunctive therapies, post-stabilization care, and management of complications from envenomation and therapy.</p> <p>Conclusions</p> <p>Clinical manifestations and ideal treatment of crotaline snakebite differ greatly, and can result in severe complications. Using a modified Delphi method, we provide evidence-informed treatment guidelines in an attempt to reduce variation in care and possibly improve clinical outcomes.</p
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