1,732 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
BARTER:promoting local spending behavior
In the wake of the 2008 economic collapse, there is renewed interest in strategies for ensuring the future economic success of nations in a globalized marketplace. One of the main ideas being championed by governments is to promote growth by encouraging local spending, although it is not clear how to motivate this behavioral shift. Local currency initiatives are increasingly popular, though due to certain practicalities are rarely successful in fostering long term and widespread change in spending behaviors. We report on the development of a persuasive system (BARTER) that leverages mobile and ubiquitous technology to overcome some of the limitations of local currencies, while also providing users with the insight needed to determine for themselves how local spending may benet their community
Structure of purine nucleoside phosphorylase (DeoD) from Bacillus anthracis
Protein structures from the causative agent of anthrax (Bacillus anthracis) are being determined as part of a structural genomics programme. Amongst initial candidates for crystallographic analysis are enzymes involved in nucleotide biosynthesis, since these are recognized as potential targets in antibacterial therapy. Purine nucleoside phosphorylase is a key enzyme in the purine-salvage pathway. The crystal structure of purine nucleoside phosphorylase (DeoD) from B. anthracis has been solved by molecular replacement at 2.24 Ă
resolution and refined to an R factor of 18.4%. This is the first report of a DeoD structure from a Gram-positive bacterium
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
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
The structure of Rph, an exoribonuclease from Bacillus anthracis, at 1.7 angstrom resolution
Maturation of tRNA precursors into functional tRNA molecules requires trimming of the primary transcript at both the 5' and 3' ends. Cleavage of nucleotides from the 3' stem of tRNA precursors, releasing nucleotide diphosphates, is accomplished in Bacillus by a phosphate-dependent exoribonuclease, Rph. The crystal structure of this enzyme from B. anthracis has been solved by molecular replacement to a resolution of 1.7 angstrom and refined to an R factor of 19.3%. There is one molecule in the asymmetric unit; the crystal packing reveals the assembly of the protein into a hexamer arranged as a trimer of dimers. The structure shows two sulfate ions bound in the active-site pocket, probably mimicking the phosphate substrate and the phosphate of the 3'-terminal nucleotide of the tRNA precursor. Three other bound sulfate ions point to likely RNA-binding sites
Medium-term performance and maintenance of SUDS:a case-study of Hopwood Park Motorway Service Area, UK
One of the main barriers to implementing SUDS is concern about performance and maintenance costs since there are few well-documented case-studies. This paper summarizes studies conducted between 2000 and 2008 of the performance and maintenance of four SUDS management trains constructed in 1999 at the Hopwood Park Motorway Service Area, central England. Assessments were made of the wildlife value and sedimentation in the SUDS ponds, the hydraulic performance of the coach park management train, water quality in all management trains, and soil/sediment composition in the grass filter strip, interceptor and ponds. Maintenance procedures and costs were also reviewed. Results demonstrate the benefits of a management train approach over individual SUDS units for flow attenuation, water treatment, spillage containment and maintenance. Peak flows, pond sediment depth and contaminant concentrations in sediment and water decreased through the coach park management train. Of the 2007 annual landscape budget of ÂŁ15,000 for the whole site, the maintenance costs for SUDS only accounted for ÂŁ2,500 compared to ÂŁ4,000 for conventional drainage structures. Furthermore, since sediment has been attenuated in the management trains, the cost of sediment removal after the recommended period of three years was only ÂŁ554 and, if the design is not compromised, less frequent removal will be required in future
Flight service evaluation of an advanced composite empennage component on commercial transport aircraft. Phase 1: Engineering development
The empennage component selected for this program is the vertical fin box of the L-1011 aircraft. The box structure extends from the fuselage production joint to the tip rib and includes the front and rear spars. Various design options were evaluated to arrive at a configuration which would offer the highest potential for satisfying program objectives. The preferred configuration selected consists of a hat-stiffened cover with molded integrally stiffened spars, aluminum trussed composite ribs, and composite miniwich web ribs with integrally molded caps. Material screening tests were performed to select an advanced composite material system for the Advanced Composite Vertical Fin (ACFV) that would meet the program requirements from the standpoint of quality, reproducibility, and cost. Preliminary weight and cost analysis were made, targets established, and tracking plans developed. These include FAA certification, ancillary test program, quality control, and structural integrity control plans
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