1,028 research outputs found
Spartina anglica population and environmental studies within the Solent salt marsh system
No full textThe thesis examines the possible causes of decline of Spartina anglica marshes along the south coast of Britain with emphasis on the Solent marshes. The study shows that although there may be some genotypic differences between S. anglica gathered from sites in Britain. The disparities are not large enough to explain the significant differences in morphological vigour of S. anglica observed in the field. It concludes that the discrepancies observed in the field are the result of phenotypic differences resulting from environmental factors. The work shows that in the S. anglica marshes of the south coast, anaerobic soil conditions prevail with impeded drainage being the most likely cause of the dwarf growth forms and lack of re-colonisation of pans and mudflats observed in the field. The thesis concludes that the ultimate demise of the S. anglica marshes of the south coast of England is the result of frontal and creek erosion of the mature marsh and the failure of S. anglica to establish itself on the newly exposed sediments of the foreshore. When S. anglica establishes itself in a flood /ebb neutral zone of an estuary, it changes the bathymetry to that of ebb dominant morphology. As a result eroded sediment is swept away with the outgoing tide. Furthermore, S. anglica is then unable to recolonise the exposed foreshore sediments because of its low redox potential resulting from poor permeability which is the consequence of the of historic overburden pressure of a once colonising mars
CEP-1347 reduces mutant huntingtin-associated neurotoxicity and restores BDNF levels in R6/2 mice
No full textHuntington's disease (HD) is a devastating neurodegenerative disorder caused by an expanded polyglutamine repeat within the protein Huntingtin (Htt). We previously reported that mutant Htt expression activates the ERK1/2 and JNK pathways [Apostol, B.L., Illes, K., Pallos, J., Bodai, L., Wu, J., Strand, A., Schweitzer, E.S., Olson, J.M., Kazantsev, A., Marsh, J.L., Thompson, L.M., 2006. Mutant huntingtin alters MAPK signaling pathways in PC12 and striatal cells: ERK1/2 protects against mutant huntingtin-associated toxicity. Hum. Mol. Genet. 15, 273-285]. Chemical and genetic modulation of these pathways promotes cell survival and death, respectively. Here we test the ability of two closely related compounds, CEP-11004 and CEP-1347, which inhibit Mixed Lineage Kinases (MLKs) and are neuroprotective, to suppress mutant Htt-mediated pathogenesis in multiple model systems. CEP-11004/CEP-1347 treatment significantly decreased toxicity in mutant Htt-expressing cells that evoke a strong JNK response. However, suppression of cellular dysfunction in cell lines that exhibit only mild Htt-associated toxicity and little JNK activation was associated with activation of ERK1/2. These compounds also reduced neurotoxicity in immortalized striatal neurons from mutant knock-in mice and Drosophila expressing a mutant Htt fragment. Finally, CEP-1347 improved motor performance in R6/2 mice and restored expression of BDNF, a critical neurotrophic factor that is reduced in HD. These studies suggest a novel therapeutic approach for a currently untreatable neurodegenerative disease, HD, via CEP-1347 up-regulation of BDNF
The life and works of James Miller, 1704-1744, with particular reference to the satiric content of his poetry and plays.
No full textPhDJames Miller was born the son of a Dorset rector in 1704. He
was himself ordained, but acquired no benefice until just before his
early death, probably because of a scathing portrayal of the Bishop
of London in one of his verse satires. At Oxford he wrote a vivacious
comedy of humours, set in the University. Its production in 1730
began his dramatic career, at a time when the number of London
theatres had just doubled, and new dramatic forms were being invented.
In 1731 his poem Harlequin-Horace, a witty inversion of
the Ars Poetica, attacked pantomime and opera, but also painted a
lively portrait of the entire theatrical world, in the tradition of
the Dunciad.
After collaborating in a translation of Moliere's works Miller
wrote two plays based on this author. Of all his dramatic works
these were the most successful with his contemporaries, and were
followed by a modernisation of Much Ado, and a ballad-opera adapted
from an afterpiece by Jean-Baptiste Rousseau, and rendered highly
topical. Miller made similar use of a recent French comedy showing
a Red Indian's reactions to civilisation, a satiric "fable" by Walsh
and Voltaire's Mahomet. A large quantity of original material was
incorporated into most of these, and this is generally satirical in
nature. The Indian is made to voice almost egalitarian sentiments.
An afterpiece, "The Camp Visitants", satirised military inaction
in the war, and was apparently banned. The manuscripts of the six
plays produced after the Licensing Act bear the examiner's deletions,
and illustrate the nature of the censorship at this time.
Miller's greatest strength is probably his flexible, vigorously
colloquial dialogue. His political satire is mostly contained in
the poetry, which attacks Walpole's administration with increasing
vehemence through the seventeen-thirties, until its fall. In 1740
two poems that used Pope in symbolic contrast to Walpole caused a
sensation. In both poetry and plays Miller is also a social satirist,
who lays unusually strong emphasis on false taste and the deterioration
of culture
Tele-operated climbing and mobile service robots for remote inspection and maintenance in nuclear industry
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Stable isotopes, Sr/Ca, and Mg/Ca in biogenic carbonates from Petaluma Marsh, northern California, USA
No full textStable isotope (18O/16O and 13C/12C) and minor-element compositions (Sr/Ca and Mg/Ca ratios) of ostracodes and gastropods separated from marsh sediments from San Francisco Bay, Northern California, were used to reconstruct paleoenvironmental changes in Petaluma Marsh over the past 700 yr. The value of d18O in the marsh carbonates reflects changes in freshwater inflow, evaporation, and temperature. Mg/Ca and Sr/Ca in ostracode calcite reflect changes in both freshwater inflow and temperature, although primarily reflect temperature changes in the salinity range of about 10-35 o/oo. Ostracode d18O values show a gradual increase by 5 o/oo between 500 yr BR and the present, probably reflecting rising sea level and increased evaporation in the marsh. Superimposed on this trend are higher frequency Mg/Ca and d18O variations (3-4 o/oo), probably reflecting changes in freshwater inflow and evaporation. A period of low Mg/Ca occurred between about 100-300 cal yr BR, suggesting wetter and cooler conditions during the Little Ice Age. Higher Mg/Ca ratios occurred 600-700 cal yr BR, indicating drier and warmer conditions during the end of the Medieval Warm Period. Both ostracode and gastropod d13C values decrease up-core, reflecting decomposition of marsh vegetation, which changes from C4 (d13C ~; -12 o/oo) to CAM (d13C = -26 o/oo)-type vegetation over time
Physicochemical changes to soil and sediment in managed realignment sites following tidal inundation
No full textPhDThe recognition of the value of salt marshes and concerns over salt marsh loss has led to
the adoption of managed realignment in coastal areas. Managed realignment involves the
landward relocation of the seawall, allowing an area of agricultural land to be tidally
inundated. It is believed that managed realignment sites can act as a sink for
contaminants. However, these sites may also act as a contaminant source and pose a
risk to estuarine biota.
In this thesis, the potential for metal and herbicide release from agricultural soil and
dredged sediment in managed realignment sites was investigated by laboratory
microcosm experiments. The agricultural soil and dredged sediment were subjected to
two different salinities and drying-rewetting treatments. Results indicate the release of
metals (Cu, Ni and Zn) and herbicides (simazine, atrazine and diuron) was dependent on
their strength of binding to the soil and sediment, and complexation and competition
reactions between seawater anions, cations and the sorbed metals. The release patterns
indicated that metal and herbicide release into overlying water may continue for extended
periods of time after an initial rapid release. The total metal and herbicide loads released
into the overlying water followed the order: Cu < Zn < Ni and diuron < atrazine < simazine
with a greater release from the soil than sediment. The increase in CO2 release,
mineralisation rates, total metal and herbicide loads after drying and rewetting the soil
suggested an increase in the mineralisation of organic matter and the release of organic
matter associated metals and herbicides. Results of linear regression analyses provided
evidence that the release of the metals and herbicides as DOC-complexes was important
for soil but not for sediment. These findings indicate that there is a lower potential for
contaminant release from managed realignment sites where dredged sediments are
beneficially re-used
Live axonal transport disruption by mutant huntingtin fragments in Drosophila motor neuron axons
No full textHuntington's Disease is a neurodegenerative condition caused by a polyglutamine expansion in thehuntingtin (Htt) protein, which aggregates and also causes neuronal dysfunction. Pathogenic N-terminal httfragments perturb axonal transport in vitro. To determine whether this occurs in vivo and to elucidate howtransport is affected, we expressed htt exon 1 with either pathogenic (HttEx1Q93) or non-pathogenic (HttEx1Q20) polyglutamine tracts in Drosophila. We found that HttEx1Q93 expression causes axonalaccumulation of GFP-tagged fast axonal transport vesicles in vivo and leads to aggregates within larval motorneuron axons. Time-lapse video microscopy, shows that vesicle velocity is unchanged in HttEx1Q93-axonscompared to HttEx1Q20-axons, but vesicle stalling occurs to a greater extent. Whilst HttEx1Q93 expressiondid not affect locomotor behaviour, external heat stress unveiled a locomotion deficit in HttEx1Q93 larvae.Therefore vesicle transport abnormalities amidst axonal htt aggregation places a cumulative burden uponnormal neuronal function under stressful conditions
Network partitioning techniques based on network natural properties for power system application
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 10/04/2002.In this thesis, the problem of partitioning a network into interconnected sub-networks is addressed. The goal is to achieve a partitioning which satisfies a set of specific engineering constraints, imposed in this case, by the requirements of the decomposed state-estimation (DSE) in electrical power systems. The network-partitioning problem is classified as NP-hard problem. Although many heuristic algorithms have been proposed for its solution, these often lack directness and computational simplicity. In this thesis, three new partitioning techniques are described which (i) satisfy the DSE constraints, and (ii) simplify the NP-hard problem by using the natural graph properties of a network. The first technique is based on partitioning a spanning tree optimally using the natural property of the spanning tree branches. As with existing heuristic techniques, information on the partitioning is obtained only at the end of the partitioning process. The study of the DSE constraints leads to define conditions of an ideal balanced partitioning. This enables data on the balanced partitioning to be obtained, including the numbers of boundary nodes and cut-edges. The second partitioning technique is designed to obtain these data for a given network, by finding the minimum covering set of nodes with maximum nodal degree. Further simplification is then possible if additional graph-theoretical properties are used. A new natural property entitled the 'edge state phenomenon' is defined. The edge state phenomenon may be exploited to generate new network properties. In the third partitioning technique, two of these, the 'network external closed path' and the 'open internal paths', are used to identify the balanced partitioning, and hence to partition the network. Examples of the application of all three methods to network partitioning are provided
Optimizing green space locations to reduce daytime and nighttime urban heat island effects in Phoenix, Arizona
No full textabstract: The urban heat island effect is especially significant in semi-arid climates, generating a myriad of problems for large urban areas. Green space can mitigate warming, providing cooling benefits important to reducing energy consumption and improving human health. The arrangement of green space to reap the full potential of cooling benefits is a challenge, especially considering the diurnal variations of urban heat island effects. Surprisingly, methods that support the strategic placement of green space in the context of urban heat island are lacking. Integrating geographic information systems, remote sensing, spatial statistics and spatial optimization, we developed a framework to identify the best locations and configuration of new green space with respect to cooling benefits. The developed multi-objective model is applied to evaluate the diurnal cooling trade-offs in Phoenix, Arizona. As a result of optimal green space placement, significant cooling potentials can be achieved. A reduction of land surface temperature of approximately 1–2 °C locally and 0.5 °C regionally can be achieved by the addition of new green space. 96% of potential day and night cooling benefits can be achieved through simultaneous consideration. The results also demonstrate that clustered green space enhances local cooling because of the agglomeration effect; whereas, dispersed patterns lead to greater overall regional cooling. The optimization based framework can effectively inform planning decisions with regard to green space allocation to best ameliorate excessive heat.Corresponding Author:
Yujia Zhang
Arizona State University
[email protected]
Sicily and the Sicilians
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Previous issue date: 1889Thesis (B.L.)--University of Illinois, 1889.Ms.Lacking title page; title and author information from table of contents at beginning of volume. IU-RBound with 11 other B.L. theses from UIUC, 1889. IU-
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