1,389 research outputs found
Terrestrial planet formation in low eccentricity warm-Jupiter systems
We examine the effect of giant planet migration on the formation of inner
terrestrial planet systems. We consider situations in which the giant planet
halts migration at semi-major axes in the range 0.13 - 1.7 AU due to gas disk
dispersal. An N-body code is employed that is linked to a viscous gas disk
algorithm capable of simulating: gas loss via accretion onto the central star
and photoevaporation; gap formation by the giant planet; type II migration of
the giant; optional type I migration of protoplanets; gas drag on
planetesimals. We find that most of the inner system planetary building blocks
survive the passage of the giant planet, either by being shepherded inward or
scattered into exterior orbits. Systems of one or more hot-Earths are predicted
to form and remain interior to the giant planet, especially if type II
migration has been limited, or where type I migration has affected
protoplanetary dynamics. Habitable planets in low eccentricity warm-Jupiter
systems appear possible if the giant planet makes a limited incursion into the
outer regions of the habitable zone (HZ), or traverses its entire width and
ceases migrating at a radial distance of less than half that of the HZ's inner
edge. We conclude that Type II migration does not prevent terrestrial planet
formation.Comment: Accepted for publication in A&A; 18 pages, 12 figures, 2 table
On the formation of terrestrial planets in hot-Jupiter systems
We present a series of calculations aimed at examining how an inner system of
planetesimals/protoplanets, undergoing terrestrial planet formation, evolves
under the influence of a giant planet undergoing inward type II migration
through the region bounded between 5 - 0.1 AU. We find that > 60% of the solids
disk survives by being scattered by the giant planet into external orbits.
Planetesimals are scattered outward almost as efficiently as protoplanets,
resulting in the regeneration of a solids disk where dynamical friction is
strong and terrestrial planet formation is able to resume. A simulation
extended for a few Myr after the migration of the giant planet halted at 0.1
AU, resulted in an apparently stable planet of ~ 2 Earth masses forming in the
habitable zone. Migration-induced mixing of volatile-rich material from beyond
the `snowline' into the inner disk regions means that terrestrial planets that
form there are likely to be water-rich. We predict that hot--Jupiter systems
are likely to harbor water-rich terrestrial planets in their habitable zones.
These planets may be detected by future planet search missions.Comment: 18 pages, 13 figures. Higher resolution pdf available at
http://www.users.globalnet.co.uk/~mfogg/fogg_nelson2.pd
Adherence to a Six-Dose Regimen of Artemether-Lumefantrine for Treatment of Uncomplicated Plasmodium Falciparum Malaria in Uganda.
Measuring baseline levels of adherence and identifying risk factors for non-adherence are important steps before the introduction of new antimalarials. In Mbarara in southwestern Uganda, we assessed adherence to artemether-lumefantrine (Coartem) in its latest World Health Organization blister formulation. Patients with uncomplicated Plasmodium falciparum malaria were prescribed artemether-lumefantrine and received an explanation of how to take the following five doses at home. A tablet count was made and a questionnaire was completed during a home visit. Among 210 analyzable patients, 21 (10.0%) were definitely or probably non-adherent, whereas 189 (90.0%) were probably adherent. Age group was not associated with adherence. Lack of formal education was the only factor associated with non-adherence after controlling for confounders (odds ratio = 3.1, 95% confidence interval [CI] = 1.1-9.7). Mean lumefantrine blood levels were lower among non-adherent (n = 16) (2.76 microg/mL, 95% CI = 1.06-4.45) than among adherent (n = 171) (3.19 microg/mL, 95% CI = 2.84-3.54) patients, but this difference was not statistically significant. The high adherence to artemether-lumefantrine found in our study suggest that this drug is likely to be very effective in Mbarara provided that patients receive clear dosage explanations
Variation in Permeability and Treatability in Shortleaf Pine and Yellow Poplar
Superficial gas permeability determinations were made for longitudinal, radial, and tangential flow on samples removed from different heights, radii, and distances along the radii in a young and a mature shortleaf pine (Pinus echinata Mill.) and in a yellow poplar (Liriodendron tulipifera L.). Permeability was measured at a mean pressure of 2.2 atmospheres and the wood was maintained at about 18% moisture content. Some of the samples were then pressure-treated with creosote under controlled conditions to estimate treatability. Specific gravity and latewood per cent were also determined. In the young pine, position in the tree showed no effect on permeability, whereas in the mature pine a slight increase with height and a sharp increase with distance from the pith were detected. In yellow poplar, an increase of permeability with distance outwards along the radius was detected, but no consistent height change. Treatability, particularly retention, was moderately correlated with permeability, particularly in shortleaf pine. In yellow poplar, inclusion of permeability values for all three structural directions was necessary to obtain correlation. All relationships were improved by transforming the permeability logarithmically. Specific gravity and latewood relationships with permeability were conflicting. Use of a mean pressure higher than atmospheric appeared to be advantageous in permeability determinations
Olive Schreiner in Rhodesia: an episode in a biography
Readers of biographies of Olive Schreiner - except for the pioneering work of Vera Buchanan-Gould (see 1948, 198-99) - could be forgiven for doubting whether Olive Schreiner ever was in Rhodesia. Although her husband's edition of her Letters includes three which cover this journey (Cronwright-Schreiner 1924a), he makes no mention of it in his Life (1924), and it is not touched on either in First and Scott (1980) or in Stanley's impressive biographical chapter (2002). Arguably, it does nothing to alter the by now well-established outlines of Olive Schreiner's life; yet, as we shall see, the visit itself might have meant the premature end of that life. Moreover, it documents Schreiner's visit to two sites of immense importance to her : the 'Hanging Tree' in Bulawayo which features in the (deliberately shocking) photographic frontispiece to the first edition of Trooper Peter Halket of Mashonaland (1897), and, secondly, Cecil Rhodes's grave in the Matopos. In just over a decade (13 Aug. 1921), she too would lie in her chosen mountaintop tomb
Olive Schreiner at 150: some thoughts on re-editing Cronwright's The Reinterment on Buffelskop
[From the introduction]: The original edition of Cronwrightâs The Reinterment on Buffelskop (1983) was produced by Guy Butler and Nick Visser to commemorate the centenary of the 1883 publication of The Story of an African Farm. The Butler-Visser text was a photographic reproduction of a typed carbon copy of the first part of Cronwrightâs extant diaries plus a special diary he had kept covering in detail the events of the actual reinterment. (The originals are now at the National English Literary Museum [NELM].) Butler included a comprehensive and illuminating introduction to these texts, as well as â under separate soft cover â a set of âProvisional Notesâ which draw deeply on his own and his familyâs accumulated knowledge of Cradock, its environs and inhabitants. In addition, Butler and Visser included two passages excised by Cronwright from the typescript of his Life of Olive Schreiner: a word picture of Charles Heathcote, and the longer account of âThe Nienaber Incidentâ â pages which deal with the execution of three innocent men at De Aar on 19 March 1901, and Cronwrightâs subsequent attempts at legal reparation for them and their families. The substantive text of the Butler-Visser edition is often difficult to read because of the method of reproduction; moreover, because it also reproduces Cronwrightâs emendations (in ink) of the typescript, it is frankly uninviting. Thus, when the NELM Council proposed a publication commemorating the 150th anniversary of Olive Schreinerâs birth on 24 March 1855, it seemed appropriate that a second attempt be made to give students of Olive Schreinerâs works easier access to Cronwrightâs detailed account of this âbizarre, romanticâ episode. Furthermore, from the perspective of text history, the typescript of the Reinterment antedates both Cronwrightâs Life and The Letters of Olive Schreiner. Parts of it are clearly Cronwrightâs preliminary ânotes towardsâ his Life, and, as Butler hypothesizes, the whole of the Reinterment might have been intended as a separate (and earlier) publication. Finally, the sarcophagus on Buffelskop is one of South Africaâs more noteworthy literary shrines: while the idea of re-editing an account of Olive Schreinerâs reinterment might be thought to be a futile exercise in intellectual recycling, our intention is that both husband and wife should live again through a rediscovery of the thoughts and feelings that led them to this dramatic final resting-place
Evidence of traffic-related pollutant control in soil-based Sustainable Urban Drainage Systems (SUDS)
SUDS are being increasingly employed to control highway runoff and have the potential to protect groundwater and surface water quality by minimising the risks of both point and diffuse sources of pollution. While these systems are effective at retaining polluted solids by filtration and sedimentation processes, less is known of the detail of pollutant behaviour within SUDS structures. This paper reports on investigations carried out as part of a co-ordinated programme of controlled studies and field measurements at soft-engineered SUDS undertaken in the UK, observing the accumulation and behaviour of traffic-related heavy metals, oil and PAHs. The field data presented were collected from two extended detention basins serving the M74 motorway in the south-west of Scotland. Additional data were supplied from an experimental lysimeter soil core leaching study. Results show that basin design influences pollutant accumulation and behaviour in the basins. Management and/or control strategies are discussed for reducing the impact of traffic-related pollutants on the aqueous environment
Development of an embedded Fabry Perot Fiber Optic Strain Rosette Sensor (FP-FOSRS)
We investigate the feasibility of utilizing a Fabry-Perot Fiber Optic Strain Rosette Sensor (FP-FOSRS) for the evaluation of the internal strain state of a material system. We briefly describe the manufacturing process for this sensor and point out some potential problem areas. Results of an embedded FP-FOSRS in an epoxy matrix with external resistance strain gauges applied for comparative purposes are presented. We show that the internal and external strain measurements are in close agreement. This work lays the foundation for embedding this sensor in actual composite laminas
London Creative and Digital Fusion
date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000date-added: 2015-03-24 04:16:59 +0000 date-modified: 2015-03-24 04:16:59 +0000The London Creative and Digital Fusion programme of interactive, tailored and in-depth support was designed to support the UK capitalâs creative and digital companies to collaborate, innovate and grow. London is a globally recognised hub for technology, design and creative genius. While many cities around the world can claim to be hubs for technology entrepreneurship, Londonâs distinctive potential lies in the successful fusion of world-leading technology with world-leading design and creativity. As innovation thrives at the edge, where better to innovate than across the boundaries of these two clusters and cultures? This booklet tells the story of Fusionâs innovation journey, its partners and its unique business support. Most importantly of all it tells stories of companies that, having worked with London Fusion, have innovated and grown. We hope that it will inspire others to follow and build on our beginnings.European Regional Development Fund 2007-13
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