172 research outputs found
Manifest Content Without a Dreamer: A Freudian Analysis of Percival Everett’s Erasure
This paper will provide a Freudian analysis of Erasure in order to prove that Everett is, in fact, the two main characters he has created, as well as attempt to challenge the stigma of interpreting through a psychoanalytical lens, rather than treating writing and literature as manifest content without a dreamer
Crisphead lettuce (lactuca sativa l.) cultivar evaluation and response of transplants to nitrogen nutrition
Experiments were conducted with lettuce at the field and in the glasshouse at the Hatfield Experimental Farm, University of Pretoria. The objectives of the study were to evaluate the performance of selected crisphead lettuce cultivars in relation to yield and quality performance and to investigate which level of nitrogen can produce high quality transplants. In the lettuce cultivar trial, fifteen crisphead lettuce cultivars were grown, during March to May 2004. The experiment was laid out as a randomised complete block design with four replications. At harvest, the centre 20 plants were cut for yield determination and five uniform plants were then cut longitudinally for head quality characteristics. For each cultivar, compactness and uniformity were also evaluated and the number of days to maturity was recorded. Among the cultivars tested, the best yielding cultivars were Dual Purpose (46.8 t•ha-1), Great Lakes (45.8 t•ha-1), Mohawk (44.3 t•ha-1) and Victory (43.9 t•ha-1). Poor yielding cultivars were Taina (30.5 t•ha-1), Cannon (31.5 t•ha-1), Summer Time (32.1 t•ha-1) and Classic (33.2 t•ha-1). Del Rio was the best disease resistant cultivar, producing 100% marketable heads. All cultivars tested had good compactness and uniformity with the exception of Great Lakes 659. Early-maturing cultivars were ready 60 days after transplanting. Seeds of the lettuce cultivar ‘Aviram’ were sown, in the nitrogen nutrition of lettuce transplant’s trial. Two days after seeding, the seedlings were fertigated every second day by floating the trays in the plastic-lined tubs containing nutrient solution at 0, 30, 60,90 and 120 mg•L-1 N until field capacity was reached. Transplants produced with 0 N grew poorly, regardless of the sampling date. Nitrogen at 120 mg• L-1 improved the response of shoot growth, plant height and leaf area, but adversely affected root growth. In general, relative growth rate was improved while net assimilation rate was reduced as N level increased. Root: shoot ratio decreased with applied N. The largest values of root: shoot ratio were obtained with 0 N. Both specific leaf area and leaf area ratio increased with applied N. Leaf mass ratio improved, while root mass ratio was reduced as N levels increased. At 35 days after sowing, leaf tissue N increased from 0.43 to 4.15 mg•kg-1 with N applied. Only 25% of the plants produced without N could be pulled from the seedling trays, whereas 90% could be pulled when 90 mg•L-1 N was added. This work suggested that at least 90 mg•L-1N, supplied via floatation irrigation was required to produce a transplant with sufficient roots for ease of pulling. Applying 90 mg•L-1 N, resulted in improved root and shoot growth, resulting in high quality transplants.Dissertation (M Inst Agrar (Horticulture))--University of Pretoria, 2007.Plant Production and Soil Scienceunrestricte
Reading and company: embodiment and social space in silent reading practices
Reading, even when silent and individual, is a social phenomenon and has often been studied as such. Complementary to this view, research has begun to explore how reading is embodied beyond simply being ‘wired’ in the brain. This article brings the social and embodied perspectives together in a very literal sense. Reporting a qualitative study of reading practices across student focus groups from six European countries, it identifies an underexplored factor in reading behaviour and experience. This factor is the sheer physical presence, and concurrent activity, of other people in the environment where one engages in individual silent reading. The primary goal of the study was to explore the role and possible associations of a number of variables (text type, purpose, device) in selecting generic (e.g. indoors vs outdoors) as well as specific (e.g. home vs library) reading environments. Across all six samples included in the study, participants spontaneously attested to varied, and partly surprising, forms of sensitivity to company and social space in their daily efforts to align body with mind for reading. The article reports these emergent trends and discusses their potential implications for research and practice
The neurological assessment in young children treated with artesunate monotherapy or artesunate-mefloquine combination therapy for uncomplicated Plasmodium falciparum malaria
<p>Abstract</p> <p>Background</p> <p>Mefloquine and artesunate combination therapy is the recommended first-line treatment for uncomplicated malaria throughout much of south-east Asia. Concerns have been raised about the potential central nervous system (CNS) effects of both drug components and there are no detailed reports in very young children.</p> <p>Methods</p> <p>Children, aged between three months and five years, with acute uncomplicated <it>Plasmodium falciparum </it>malaria were randomized to either 7 days of artesunate monotherapy or the same schedule of artesunate plus mefloquine on day 7 and 8. Neurological testing targeting coordination and behaviour was carried out at day 0, 7, 9, 10, 14 and 28. Non-febrile healthy control children from the same population were tested on days 0, 7, 14 and 28.</p> <p>Results</p> <p>From December 1994 to July 1997, 91 children with uncomplicated <it>P. falciparum</it>, 45 treated with artesunate monotherapy, 46 treated with mefloquine and artesunate combination therapy and 36 non-febrile controls, underwent neurological testing. Malaria and fever had a significant negative impact on testing performance. By contrast, the anti-malarial treatments were not associated with worsening performances in the various components of the test. Artesunate and mefloquine do not appear to have a significant influence on coordination and behaviour. Children treated with mefloquine were significantly less likely to suffer recurrent malaria infection during follow-up compared to those treated with artesunate alone (P = 0.033).</p> <p>Conclusion</p> <p>In keeping with the results of randomized controlled trials in adults, mefloquine was not associated with a decrease in specific items of neurological performance. Likewise, children treated with artesunate did not perform significantly differently to control children. This study does not exclude subtle or rare treatment CNS effects of artesunate or mefloquine. Treatment of acute uncomplicated malaria results in a significant improvement on items of neurological performance.</p
Dust-Obscured Star-Formation in Intermediate Redshift Galaxy Clusters
We present Spitzer MIPS 24-micron observations of 16 0.4<z<0.8 galaxy
clusters drawn from the ESO Distant Cluster Survey (EDisCS). This is the first
large 24-micron survey of clusters at intermediate redshift. The depth of our
imaging corresponds to a total IR luminosity of 8x10^10 Lsun, just below the
luminosity of luminous infrared galaxies (LIRGs), and 6^{+1}_{-1}% of M_V < -19
cluster members show 24-micron emission at or above this level. We compare with
a large sample of coeval field galaxies and find that while the fraction of
cluster LIRGs lies significantly below that of the field, the IR luminosities
of the field and cluster galaxies are consistent. However, the stellar masses
of the EDisCS LIRGs are systematically higher than those of the field LIRGs. A
comparison with optical data reveals that ~80% of cluster LIRGs are blue and
the remaining 20% lie on the red sequence. Of LIRGs with optical spectra,
88^{+4}_{-5}% show [O II] emission with EW([O II])>5A, and ~75% exhibit optical
signatures of dusty starbursts. On average, the fraction of cluster LIRGs
increases with projected cluster-centric radius but remains systematically
lower than the field fraction over the area probed (< 1.5xR200). The amount of
obscured star formation declines significantly over the 2.4 Gyr interval
spanned by the EDisCS sample, and the rate of decline is the same for the
cluster and field populations. Our results are consistent with an exponentially
declining LIRG fraction, with the decline in the field delayed by ~1 Gyr
relative to the clusters.Comment: 15 pages, 9 figure
Fitting the integrated Spectral Energy Distributions of Galaxies
Fitting the spectral energy distributions (SEDs) of galaxies is an almost
universally used technique that has matured significantly in the last decade.
Model predictions and fitting procedures have improved significantly over this
time, attempting to keep up with the vastly increased volume and quality of
available data. We review here the field of SED fitting, describing the
modelling of ultraviolet to infrared galaxy SEDs, the creation of
multiwavelength data sets, and the methods used to fit model SEDs to observed
galaxy data sets. We touch upon the achievements and challenges in the major
ingredients of SED fitting, with a special emphasis on describing the interplay
between the quality of the available data, the quality of the available models,
and the best fitting technique to use in order to obtain a realistic
measurement as well as realistic uncertainties. We conclude that SED fitting
can be used effectively to derive a range of physical properties of galaxies,
such as redshift, stellar masses, star formation rates, dust masses, and
metallicities, with care taken not to over-interpret the available data. Yet
there still exist many issues such as estimating the age of the oldest stars in
a galaxy, finer details ofdust properties and dust-star geometry, and the
influences of poorly understood, luminous stellar types and phases. The
challenge for the coming years will be to improve both the models and the
observational data sets to resolve these uncertainties. The present review will
be made available on an interactive, moderated web page (sedfitting.org), where
the community can access and change the text. The intention is to expand the
text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics &
Space Scienc
Does a coupling capacitor enhance the charge balance during neural stimulation? An empirical study
Implications of fisheries-induced evolution for stock rebuilding and recovery
Worldwide depletion of fish stocks has led fisheries managers to become increasingly concerned about rebuilding and recovery planning. To succeed, factors affecting recovery dynamics need to be understood, including the role of fisheries-induced evolution. Here we investigate a stock's response to fishing followed by a harvest moratorium by analyzing an individual-based evolutionary model parameterized for Atlantic cod Gadus morhua from its northern range, representative of long-lived, late-maturing species. The model allows evolution of life-history processes including maturation, reproduction, and growth. It also incorporates environmental variability, phenotypic plasticity, and density-dependent feedbacks. Fisheries-induced evolution affects recovery in several ways. The first decades of recovery were dominated by demographic and density-dependent processes. Biomass rebuilding was only lightly influenced by fisheries-induced evolution, whereas other stock characteristics such as maturation age, spawning stock biomass, and recruitment were substantially affected, recovering to new demographic equilibria below their preharvest levels. This is because genetic traits took thousands of years to evolve back to preharvest levels, indicating that natural selection driving recovery of these traits is weaker than fisheries-induced selection was. Our results strengthen the case for proactive management of fisheries-induced evolution, as the restoration of genetic traits altered by fishing is slow and may even be impractical
Simulating micro-scale thermal interactions in different building environments for mitigating urban heat islands
Environmental Barcoding Reveals Massive Dinoflagellate Diversity in Marine Environments
Rowena F. Stern is with University of British Columbia, Ales Horak is with University of British Columbia, Rose L. Andrew is with University of British Columbia, Mary-Alice Coffroth is with State University of New York at Buffalo, Robert A. Andersen is with the Bigelow Laboratory for Ocean Sciences, Frithjof C. Küpper is with the Scottish Marine Institute, Ian Jameson is with CSIRO Marine and Atmospheric Research, Mona Hoppenrath is with the German Center for Marine Biodiversity Research, Benoît Véron is with University of Caen Lower Normandy and the National Institute for Environmental Studies, Fumai Kasai is with the National Institute for Environmental Studies, Jerry Brand is with UT Austin, Erick R. James is with University of British Columbia, Patrick J. Keeling is with University of British Columbia.Background -- Dinoflagellates are an ecologically important group of protists with important functions as primary producers, coral symbionts and in toxic red tides. Although widely studied, the natural diversity of dinoflagellates is not well known. DNA barcoding has been utilized successfully for many protist groups. We used this approach to systematically sample known “species”, as a reference to measure the natural diversity in three marine environments. Methodology/Principal Findings -- In this study, we assembled a large cytochrome c oxidase 1 (COI) barcode database from 8 public algal culture collections plus 3 private collections worldwide resulting in 336 individual barcodes linked to specific cultures. We demonstrate that COI can identify to the species level in 15 dinoflagellate genera, generally in agreement with existing species names. Exceptions were found in species belonging to genera that were generally already known to be taxonomically challenging, such as Alexandrium or Symbiodinium. Using this barcode database as a baseline for cultured dinoflagellate diversity, we investigated the natural diversity in three diverse marine environments (Northeast Pacific, Northwest Atlantic, and Caribbean), including an evaluation of single-cell barcoding to identify uncultivated groups. From all three environments, the great majority of barcodes were not represented by any known cultured dinoflagellate, and we also observed an explosion in the diversity of genera that previously contained a modest number of known species, belonging to Kareniaceae. In total, 91.5% of non-identical environmental barcodes represent distinct species, but only 51 out of 603 unique environmental barcodes could be linked to cultured species using a conservative cut-off based on distances between cultured species. Conclusions/Significance -- COI barcoding was successful in identifying species from 70% of cultured genera. When applied to environmental samples, it revealed a massive amount of natural diversity in dinoflagellates. This highlights the extent to which we underestimate microbial diversity in the environment.This project was funded by Genome Canada and the Canadian Barcode of Life Network. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Biological Sciences, School o
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