8,729 research outputs found
Outer zone electrons
Spatial and temporal behavior of high energy trapped electrons in outer zone of magnetospher
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Analysis of gas chromatography/mass spectrometry data for catalytic lignin depolymerization using positive matrix factorization
Various catalytic technologies are being developed to efficiently convert lignin into renewable chemicals. However, due to its complexity, catalytic lignin depolymerization often generates a wide and complex distribution of product compounds. Gas chromatography/mass spectrometry (GC-MS) is a common analytical technique to profile the compounds that comprise lignin depolymerization products. GC-MS is applied not only to determine the product composition, but also to develop an understanding of the catalytic reaction pathways and of the relationships among catalyst structure, reaction conditions, and the resulting compounds generated. Although a very useful tool, the analysis of lignin depolymerization products with GC-MS is limited by the quality and scope of the available mass spectral libraries and the ability to correlate changes in GC-MS chromatograms to changes in lignin structure, catalyst structure, and other reaction conditions. In this study, the GC-MS data of the depolymerization products generated from organosolv hybrid poplar lignin using a copper-doped porous metal oxide catalyst and a methanol/dimethyl carbonate co-solvent was analyzed by applying a factor analysis technique, positive matrix factorization (PMF). Several different solutions for the PMF model were explored. A 13-factor solution sufficiently explains the chemical changes occurring to lignin depolymerization products as a function of lignin, reaction time, catalyst, and solvent. Overall, seven factors were found to represent aromatic compounds, while one factor was defined by aliphatic compounds
Changes in life-style after liver transplantation
Sixty-five pediatric patients who received liver transplants between May 1981 and May 1984 were observed for as many as 5 years and examined for changes in life-style. Children were less frequently hospitalized, spent less time hospitalized, required fewer medications, and generally had excellent liver and renal function after hepatic transplantation as compared with their pretransplantation status. Most children were in age-appropriate and standard school classes or were only 1 year behind. Cognitive abilities remained unchanged. Children improved in gross motor function and patients' behavior significantly improved according to parents' perceptions. Enuresis was more prevalent, however, than in the population of children who had not received liver transplants. Parental divorce rates were no greater than those reported for other families with chronically ill children. Overall, objective changes in life-style as well as parents' perceptions of behavior of children appear to be improved after liver transplantation
Social and ecological dimensions of urban conservation grasslands and their management through prescribed burning and woody vegetation removal
Natural grasslands are threatened globally. In south-eastern Australia, remnants of critically endangered natural grasslands are increasingly being isolated in urban areas. Urbanisation has led to reduced fire frequency and woody plant encroachment in some patches. Grasslands are currently being managed under the assumption that desirable management actions to address these threats (prescribed burning and removing woody vegetation) (1) lead to improved conservation outcomes and (2) are restricted by negative public attitudes. In this study, we tested these two assumptions in the context of native grassland conservation reserves in Melbourne, Australia. Firstly, we investigated differences in species and functional trait composition between patches that had been recently burnt, patches that were unburnt and patches subject to woody vegetation encroachment. We found that the functional traits of species converged in areas subject to woody plant encroachment and areas frequently disturbed by fire. Burning promoted native species, and patches of woody plants supressed the dominant grass, providing a wider range of habitat conditions. Secondly, we surveyed 477 residents living adjacent to these grassland conservation reserves to measure values, beliefs and attitudes and the acceptance of prescribed burning and removing woody vegetation. We found conflict in people's attitudes to grasslands, with both strongly positive and strongly negative attitudes expressed. The majority of residents found prescribed burning an acceptable management practice (contrary to expectations) and removing trees and shrubs from grasslands to be unacceptable. Both cognitive factors (values and beliefs) and landscape features were important in influencing these opinions. This research provides some guidance for managing urban grassland reserves as a social-ecological system, showing that ecological management, community education and engagement and landscape design features can be integrated to influence social and ecological outcomes
An Improved Algorithm for Fast K-Word Proximity Search Based on Multi-Component Key Indexes
A search query consists of several words. In a proximity full-text search, we
want to find documents that contain these words near each other. This task
requires much time when the query consists of high-frequently occurring words.
If we cannot avoid this task by excluding high-frequently occurring words from
consideration by declaring them as stop words, then we can optimize our
solution by introducing additional indexes for faster execution. In a previous
work, we discussed how to decrease the search time with multi-component key
indexes. We had shown that additional indexes can be used to improve the
average query execution time up to 130 times if queries consisted of
high-frequently occurring words. In this paper, we present another search
algorithm that overcomes some limitations of our previous algorithm and
provides even more performance gain.
This is a pre-print of a contribution published in Arai K., Kapoor S., Bhatia
R. (eds) Intelligent Systems and Applications. IntelliSys 2020. Advances in
Intelligent Systems and Computing, vol 1251, published by Springer, Cham. The
final authenticated version is available online at:
https://doi.org/10.1007/978-3-030-55187-2_3
Velocity Correlations in Driven Two-Dimensional Granular Media
Simulations of volumetrically forced granular media in two dimensions produce
s tates with nearly homogeneous density. In these states, long-range velocity
correlations with a characteristic vortex structure develop; given sufficient
time, the correlations fill the entire simulated area. These velocity
correlations reduce the rate and violence of collisions, so that pressure is
smaller for driven inelastic particles than for undriven elastic particles in
the same thermodynamic state. As the simulation box size increases, the effects
of veloc ity correlations on the pressure are enhanced rather than reduced.Comment: 12 pages, 6 figures, 21 reference
Infrared Emission from Supernova Remnants: Formation and Destruction of Dust
We review the observations of dust emission in supernova rem- nants (SNRs)
and supernovae (SNe). Theoretical calculations suggest that SNe, particularly
core-collapse, should make significant quantities of dust, perhaps as much as a
solar mass. Observations of extragalactic SNe have yet to find anywhere near
this amount, but this may be the result of observa- tional limitations. SN
1987A, in the process of transitioning from a SN to an SNR, does show signs of
a significant amount of dust forming in its ejecta, but whether this dust will
survive the passage of the reverse shock to be injected into the ISM is
unknown. IR observations of SNRs have not turned up significant quantities of
dust, and the dust that is observed is generally swept-up by the forward shock,
rather than created in the ejecta. Because the shock waves also destroy dust in
the ISM, we explore the question of whether SNe might be net destroyers, rather
than net creators of dust in the universe.Comment: Published in the Springer Handbook of Supernova
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Strategies for recruitment to a population-based lung cancer prevention trial: The CARET experience with heavy smokers
Assessing the Effects of Banana Pingers as a Bycatch Mitigation Device for Harbour Porpoises (Phocoena phocoena)
This is the final version. Available on open access from Frontiers Media via the DOI in this recordData Availability Statement:
The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation, to any qualified researcher.Bycatch is a significant cause of population declines of marine megafauna globally. While numerous bycatch mitigation strategies exist, acoustic alarms, or pingers, are the most widely adopted strategy for small cetaceans. Although pingers have been shown to be an effective measure for numerous species, there are some concerns about their long-term use. Bycatch is recognized as a persistent problem in waters around Cornwall, United Kingdom, where several cetacean species are resident, with harbour porpoises (Phocoena phocoena) being the most-commonly sighted. In this study, we assessed the effects of a Banana Pinger (Fishtek Marine Limited) on harbour porpoises in Cornwall between August 2012 and March 2013. Two passive acoustic loggers (C-PODs; Chelonia Limited) were deployed 100 m apart to record cetacean activity during cycles of active and inactive pinger periods. Harbour porpoises were 37% less likely to be detected at the C-POD near the pinger when the pinger was active, while they were only 9% less likely to be detected 100 m further away. The effect of the pinger was constant over the study period at both C-PODs despite the temporal variation in harbour porpoise detections. In addition, we found no evidence of reduced pinger effect with changing environmental conditions. Furthermore, harbour porpoise detections at the C-POD near the pinger did not depend on the time elapsed since the pinger turned off, with harbour porpoises returning to the ensonified area with no delay. Together these results suggest that (1) harbour porpoises did not habituate to the pinger over an 8-month period, (2) the pinger effect is very localized, and (3) pinger use did not lead to harbour porpoise displacement over the study period, suggesting an absence of long-term behavioral effects. We suggest that the deployment of pingers on fishing nets would likely reduce net-porpoise interactions, thereby mitigating bycatch of harbour porpoises and potentially other cetacean species. As the small-scale fishery dominates in United Kingdom waters, there is an acute need for cost-effective mitigation strategies with concurrent monitoring to be implemented rapidly in order to address the problem of harbour porpoise, and more generally, cetacean bycatch.Whale and Dolphin ConservationFishtek Marine Limite
Check the Head: Emergency Ultrasound Diagnosis of Fetal Anencephaly
Background Early pregnancy complaints in emergency medicine are common. Emergency physicians (EP) increasingly employ ultrasound (US) in the evaluation of these complaints. As a result, it is likely that rare and important diagnoses will be encountered. We report a case of fetal anencephaly diagnosed by bedside emergency US in a patient presenting with first-trimester vaginal bleeding.
Case Report A 33-year-old patient at 10 weeks gestation presented with vaginal bleeding. After initial history and physical examination, a bedside US was performed. The EP noted the abnormal appearance of the fetal cranium and anencephaly was suspected. This finding was confirmed by a consultative high-resolution fetal US. Making the diagnosis at the point of care allowed earlier detection and more comprehensive maternal counseling about pregnancy options. This particular patient underwent elective abortion which was able to be performed at an earlier gestation, thus decreasing maternal risk. If this diagnosis would not have been recognized by the EP at the point of care, it may not have been diagnosed until the second trimester, and lower-risk maternal options would not have been available. [West J Emerg Med. 2016;17(4)460-463.
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