2,951 research outputs found

    A question of continuing control -balancing building quality of housing and building codes

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    The Building Code of Australia seeks to establish &ldquo;nationally consistent, minimum necessary standards of relevant, health, safety (including structural safety and safety from fire), amenity and sustainability objectives efficiently&rdquo;. These goals are laudable &ndash; but where are the goals of quality and maintenance, which are also an essential part of achieving adequate and continuing health and safety for the built environment? Defects such as dampness, settlement and cracking, staining, wood rot, termite damage, rusting, and roof leakage are common enough to suggest that there are still issues with building quality in housing. They are caused by a combination of initial poor workmanship and poor quality materials and latterly by poorly executed or inadequate maintenance. Local architecture, developed over many years of trial and error, produce buildings linked to their climate and local materials (think of the typical &ldquo;Queenslander&rdquo; house). Today&rsquo;s architecture imports technologies and materials from many differing countries and climates &ndash; that are not necessarily suitable for the location, nor is there necessarily the same quality control over the material quality and production. Inappropriate use and inadequate understanding of new materials and techniques can lead to the generation of further defects.Whilst the building code contains provisions for initial-build material quality and workmanship, there is no continuing control over a house over its life span. Reliance is placed on advertising the need, for example, to employ qualified tradespeople; replace batteries in smoke detectors; and other good advice to help maintain housing to a minimum standard. Is this sufficient?Mechanisms to make the transfer of knowledge to those who need to use it &ndash; be it the workforce or the houseowner &ndash; need to be improved. Should the building code be more visual and accessible in it&rsquo;s content? Should the building code include provisions for maintenance? Should the building code require every house to have a &ldquo;users manual&rdquo; &ndash; much like a car? An extensive review of literature identifies the scale of the problem of poor quality housing and highlights some suggested causes &ndash; inadequate knowledge of the BCA by general housebuilders being one. However little work has been done to investigate what could be done to improve the situation. This work suggests that improvements to knowledge transfer would improve the quality of housing and a model of the knowledge transfer process is proposed, identifying those areas where the knowledge flows need to occur that would impact both the builders and users of housing.<br /

    The P Cygni supergiant [OMN2000] LS1 – implications for the star formation history of W51

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    Original article can be found at: http://www.aanda.org/ Copyright The European Southern Observatory (ESO) DOI: 10.1051/0004-6361/200911980Aims. We investigate the nature of the massive star [OMN2000] LS1 and use these results to constrain the history of star formation within the host complex W51. Methods. We utilised a combination of near-IR spectroscopy and non-LTE model atmosphere analysis to derive the physical properties of [OMN2000] LS1 , and a combination of theoretical evolutionary calculations and Monte Carlo simulations to apply limits on the star formation history of W51. Results. We find the spectrum of [OMN2000] LS1 to be consistent with that of a P Cygni supergiant. With a temperature in the range of 13.2–13.7 kK and log( ) , it is significantly cooler, less luminous, and less massive than proposed by previous authors. The presence of such a star within W51 shows that star formation has been underway for at least 3 Myr, while the formation of massive O stars is still on going. The lack of a population of evolved red supergiants within the complex shows that the rate of formation of young massive clusters at ages 9 Myr was lower than currently observed. We find no evidence of internally triggered, sequential star formation within W51, and favour the suggestion that star formation has proceeded at multiple indepedent sites within the GMC. Along with other examples, such as the G305 and Carina star-forming regions, we suggest that W51 is a Galactic analogue of the ubiquitous star cluster complexes seen in external galaxies such as M51 and NGC2403.Peer reviewe

    Computational studies on gas phase polyborate anions

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    The borate anions [B(OH)4]�, [B2O(OH)5]�, [B3O3(OH)4]�, [B3O3(OH)5]2�, [B3O3(OH)6]3�, [B4O5(OH)4]2�, [B5O6(OH)4]�, and [B7O9(OH)5]2� (2 isomers) and the neutral orthoboric and metaboric acids, B(OH)3 and B3O3(OH)3, have been structurally optimised in the gas phase at the B3LYP/6-311++G(d,p) level. Energetic data, combined with analogous data for �building blocks� H2O and [OH]�, has enabled their relative gas phase stabilities (all exothermic) to be determined using an isodesmic approach as: [B5O6(OH)4]� > [B3O3(OH)4]� > [B(OH)4]� > [B7O9(OH)5]2� > [B4O5(OH)4]2� > [B3O3(OH)5]2�. The two isomers of [B7O9(OH)5]2� have similar total energies although the �ribbon� isomer is calculated to be more stable by only 10.0 kJ mol�1. QTAIM analyses have been undertaken on all computed structures, and QTAIM charges for H, O and B atoms have been calculated. It is concluded that H-bond interactions dominate the solid-state energetics of non-metal cation polyborate salts

    Short-term outcomes of down-referral in provision of paediatric antiretroviral therapy at Red Cross War Memorial Children’s Hospital, Cape Town, South Africa: A retrospective cohort study

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    Background. The large scale-up of paediatric HIV care necessitated down-referral of many children receiving antiretroviral therapy (ART) from Red Cross War Memorial Children’s Hospital (RCWMCH), Cape Town, South Africa. Few published data exist on the outcomes of these children.Objectives. To assess outcomes of children receiving ART in the first 12 months after down-referral to primary healthcare (PHC) clinics and identify determinants of successful down-referral.Methods. A retrospective cohort study of children &lt;15 years of age who initiated ART at RCWMCH and were subsequently down-referred to one of two PHC clinics between January 2006 and December 2012 was completed. Baseline characteristics of patients and caregivers as well as CD4+ counts, viral loads (VLs) and weights were collected 6 and 12 months after down-referral. Outcomes included retention in care and viral suppression.Results. Of 116 children down-referred to the two study PHC clinics, 81.9% arrived at the designated PHC clinic and a further 8.6% continued care at other clinics, the remaining 9.5% being lost to follow-up. Of those successfully down-referred, 11.4% took &gt;8 weeks to present, possibly experiencing treatment interruption. At 12 months after down-referral, only 81.0% remained in care. No factors were associated with retention in care in multivariable analysis. For children who remained in care at the designated PHC clinics, the clinical and immunological gains achieved prior to down-referral were sustained through 12 months of follow-up, and 54.7% of this cohort had documented viral suppression at 12 months. However, if only children with VL results are considered, 75.9% (41/54) were virally suppressed 12 months after down-referral.Conclusions. Down-referral of children on ART is complex, with risk of loss to follow-up and treatment interruption

    How to Undertake a Clinically Relevant Systematic Review in a Rapidly Evolving Field: Magnetic Resonance Angiography

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    Objectives: The aim was to determine which generations of the evolving technology of magnetic resonance angiography (MRA) are currently of clinical relevance in two clinical applications. Our purpose was to plan a systematic review that would be valuable both to purchasers driven by cost-effectiveness and to practicing clinicians. Methods: Information was gathered from a search of major bibliographic databases, from a short questionnaire sent to 500 U.K. vascular radiologists and vascular surgeons, and from local clinical The authors thank A. Jackson and all those who completed a questionnaire. This work was carried out with the financial support of the Secretary of State for Health under the NHS Health Technology Assessment Programme, project 97/13/04. The views and opinions expressed do not necessarily reflect those of the Secretary of State for Health. In part, this work was undertaken by the Leeds Teaching Hospitals NHS Trust, which received funding from the NHS Executive. The views expressed in this publication are those of the authors and not necessarily those of the NHS Executive.experts. We asked which of the MRA techniques were currently used and, assuming availability, what would be their technique of choice. Results: There were 206 published articles that satisfied preliminary inclusion criteria: 69 discussed 2D time of flight (TOF); 47, 3D TOF; and 38, contrast-enhanced techniques. There were 162 questionnaires returned (60 radiologists, 102 surgeons). Of the total respondents, 77/162 (48%) used MRA in the assessment of carotid artery stenosis; 47/77 (61%) used 2D TOF; 32/77 (42%), 3D TOF; and 26/77 (34%), contrast-enhanced techniques. Thirty-five of 162 (22%) respondents used MRA in the assessment of peripheral vascular disease (PVD); 15/35 (43%) used 2D TOF, 4/35 (11%) used 3D TOF, and 22/35 (63%) used contrast-enhanced techniques. For those wishing to use MRA, contrast-enhanced techniques were the method of choice. Conclusions: The TOF methods that represent earlier generations of the technology remain clinically relevant, and will therefore be included in our systematic review. To ensure complete and relevant coverage in reviews of other evolving technologies, it would be advisable to obtain data for guidance in a similar way

    An entropic uncertainty principle for positive operator valued measures

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    Extending a recent result by Frank and Lieb, we show an entropic uncertainty principle for mixed states in a Hilbert space relatively to pairs of positive operator valued measures that are independent in some sense. This yields spatial-spectral uncertainty principles and log-Sobolev inequalities for invariant operators on homogeneous spaces, which are sharp in the compact case.Comment: 14 pages. v2: a technical assumption removed in main resul

    Use of magnetic resonance angiography to select candidates with recently symptomatic carotid stenosis for surgery: systematic review

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    Objective To determine if sufficient evidence exists to support the use of magnetic resonance angiography as a means of selecting patients with recently symptomatic high grade carotid stenosis for surgery. Design Systematic review of published research on the diagnostic performance of magnetic resonance angiography, 1990-9. Main outcome measures Performance characteristics of diagnostic test. Results 126 potentially relevant articles were identified, but many articles failed to examine die performance of magnetic resonance angiography as a diagnostic test at the surgical decision thresholds used in major clinical trials on endarterectomy. 26 articles were included in a meta-analysis that showed a maximal joint sensitivity and specificity of 99% (95% confidence interval 98% to 100%) for identifying 70-99% stenosis and 90% (81% to 99%) for identifying 50-99% stenosis. Only four articles evaluated contrast enhanced magnetic resonance angiography. Conclusions Magnetic resonance angiography is accurate for selecting patients for carotid endarterectomy at the surgical decision thresholds established in the major endarterectomy trials, but the evidence is not very robust because of the heterogeneity of the studies included. Research is to determine the diagnostic performance of the most recent developments in magnetic resonance angiography, including contrast enhanced techniques, as well as to assess the impact of magnetic resonance angiography on surgical decision making and outcomes

    Involution of the mouse mammary gland is associated with an immune cascade and an acute-phase response, involving LBP, CD14 and STAT3

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    INTRODUCTION: Involution of the mammary gland is a complex process of controlled apoptosis and tissue remodelling. The aim of the project was to identify genes that are specifically involved in this process. METHODS: We used Affymetrix oligonucleotide microarrays to perform a detailed transcript analysis on the mechanism of controlled involution after withdrawal of the pups at day seven of lactation. Some of the results were confirmed by semi-quantitative reverse transcriptase polymerase chain reaction, Western blotting or immunohistochemistry. RESULTS: We identified 145 genes that were specifically upregulated during the first 4 days of involution; of these, 49 encoded immunoglobulin genes. A further 12 genes, including those encoding the signal transducer and activator of transcription 3 (STAT3), the lipopolysaccharide receptor (CD14) and lipopolysaccharide-binding protein (LBP), were involved in the acute-phase response, demonstrating that the expression of acute-phase response genes can occur in the mammary gland itself and not only in the liver. Expression of LBP and CD14 was upregulated, at both the RNA and protein level, immediately after pup withdrawal; CD14 was strongly expressed in the luminal epithelial cells. Other genes identified suggested neutrophil activation early in involution, followed by macrophage activation late in the process. Immunohistochemistry and histological staining confirmed the infiltration of the involuting mammary tissue with neutrophils, plasma cells, macrophages and eosinophils. CONCLUSION: Oligonucleotide microarrays are a useful tool for identifying genes that are involved in the complex developmental process of mammary gland involution. The genes identified are consistent with an immune cascade, with an early acute-phase response that occurs in the mammary gland itself and resembles a wound healing process

    X-ray diffraction study of feline leukemia virus fusion peptide and lipid polymorphism

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    AbstractThe structural effects of the fusion peptide of feline leukemia virus (FeLV) on the lipid polymorphism of N-methylated dioleoylphosphatidylethanolamine were studied using a temperature ramp with sequential X-ray diffraction. This peptide, the hydrophobic amino-terminus of p15E, has been proven to be fusogenic and to promote the formation of highly curved, intermediate structures on the lamellar liquid-crystal to inverse hexagonal phase transition pathway. The FeLV peptide produces marked effects on the thermotropic mesomorphic behaviour of MeDOPE, a phospholipid with an intermediate spontaneous radius of curvature. The peptide is shown to reduce the lamellar repeat distance of the membrane prior to the onset of an inverted cubic phase. This suggests that membrane thinning may play a role in peptide-induced membrane fusion and strengthens the link between the fusion pathway and inverted cubic phase formation. The results of this study are interpreted in relation to models of the membrane fusion mechanism

    Pentaborate(1-) salts templated by substituted pyrrolidinium cations: synthesis, structural characterization, and modelling of solid-state H-bond interactions by DFT calculations

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    The synthesis and characterization of a series of pentaborate(1�) salts of substituted pyrrolidinium cations [C4H8NH2][B5O6(OH)4] (1), [C4H8NMe2][B5O6(OH)4] (2) [C4H8NMeH][B5O6(OH)4] (3), [(2-CH2OH)C4H7NH2][B5O6(OH)4] (4) is reported. All compounds were characterized by single-crystal XRD studies with 3 (1/2CH3COCH3) and 4 (1/2H2O) solvated. TGA/DSC analysis of the pentaborates 1�4 showed that they thermally decomposed in air at 800 °C to 2.5 B2O3, in a 2 step process involving dehydration (<250 °C) and oxidative decomposition (250�600 °C). BET analysis of materials derived thermally from the pentaborates 1 and 2 had internal porosities of <1 m2 g�1, indicating they were non-porous. All compounds show extensive supramolecular H-bonded anionic lattices. H-bond interactions are described in detail and motifs found in these and in other pentaborate structures have been examined and modelled by DFT calculations. These calculations confirm that H-bonds interactions in pentaborates are moderately strong (ca. �10 to �21 kJ mol�1) and are likely to dominate the energetics of their templated syntheses
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