896 resultados para Repair Maintenance Alteration and Addition Works
Resumo:
Many countries over the last decade, have used performance-based contracting (PBC) to manage and maintain roads. The implementation of PBC provides additional benefits for the government/public such as cost savings and improved conditions of contracted road assets. In Australia, PBC is already being implemented on all categories of roads: national, state, urban and rural. Australian PBC arrangement is designed to turn over control and responsibility for roadway system maintenance, rehabilitation, and capital improvement projects to private contractors. Contractors’ responsibilities include determination of treatment types, the design, programming and the undertaking of works needed to maintain road networks at predetermined performance levels. Indonesia initiated two PBC pilot projects in 2011, the Pantura Section Demak-Trengguli (7.68 kilometers) in Central Java Province and Section Ciasem-Pamanukan (18.5 kilometers) in West Java Province. Both sections are categorized as national roads. The contract duration for both of these projects is four years. To facilitate a possible way forward, it is proposed to conduct a study to understand Australia's experiences of advancing from pilot projects to nation-wide programs using PBC. The study focuses on the scope of contracts, bidding processes, risk allocation, and key drivers, using relevant PBC case studies from Australia. Recommendations for future PBC deployment nation-wide should be based on more research associated with risk allocation. This will include investigation of standard conditions of contract. Implications of the contract clauses for the risk management strategy to be adopted by contractors. Based on the nature of risks, some are best managed by the project owner. It is very important that all parties involved to be open to the new rules of contract and to convince themselves about the potential increased benefits of the use of PBC. The most recent states of challenging issues were explored and described.
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Background: The incidence of all forms of congenital heart defects is 0.75%. For patients with congenital heart defects, life-expectancy has improved with new treatment modalities. Structural heart defects may require surgical or catheter treatment which may be corrective or palliative. Even those with corrective therapy need regular follow-up due to residual lesions, late sequelae, and possible complications after interventions. Aims: The aim of this thesis was to evaluate cardiac function before and after treatment for volume overload of the right ventricle (RV) caused by atrial septal defect (ASD), volume overload of the left ventricle (LV) caused by patent ductus arteriosus (PDA), and pressure overload of the LV caused by coarctation of the aorta (CoA), and to evaluate cardiac function in patients with Mulibrey nanism. Methods: In Study I, of the 24 children with ASD, 7 underwent surgical correction and 17 percutaneous occlusion of ASD. Study II had 33 patients with PDA undergoing percutaneous occlusion. In Study III, 28 patients with CoA underwent either surgical correction or percutaneous balloon dilatation of CoA. Study IV comprised 26 children with Mulibrey nanism. A total of 76 healthy voluntary children were examined as a control group. In each study, controls were matched to patients. All patients and controls underwent clinical cardiovascular examinations, two-dimensional (2D) and three-dimensional (3D) echocardiographic examinations, and blood sampling for measurement of natriuretic peptides prior to the intervention and twice or three times thereafter. Control children were examined once by 2D and 3D echocardiography. M-mode echocardiography was performed from the parasternal long axis view directed by 2D echocardiography. The left atrium-to-aorta (LA/Ao) ratio was calculated as an index of LA size. The end-diastolic and end-systolic dimensions of LV as well as the end-diastolic thicknesses of the interventricular septum and LV posterior wall were measured. LV volumes, and the fractional shortening (FS) and ejection fraction (EF) as indices of contractility were then calculated, and the z scores of LV dimensions determined. Diastolic function of LV was estimated from the mitral inflow signal obtained by Doppler echocardiography. In three-dimensional echocardiography, time-volume curves were used to determine end-diastolic and end-systolic volumes, stroke volume, and EF. Diastolic and systolic function of LV was estimated from the calculated first derivatives of these curves. Results: (I): In all children with ASD, during the one-year follow-up, the z score of the RV end-diastolic diameter decreased and that of LV increased. However, dilatation of RV did not resolve entirely during the follow-up in either treatment group. In addition, the size of LV increased more slowly in the surgical subgroup but reached control levels in both groups. Concentrations of natriuretic peptides in patients treated percutaneously increased during the first month after ASD closure and normalized thereafter, but in patients treated surgically, they remained higher than in controls. (II): In the PDA group, at baseline, the end-diastolic diameter of LV measured over 2SD in 5 of 33 patients. The median N-terminal pro-brain natriuretic peptide (proBNP) concentration before closure measured 72 ng/l in the control group and 141 ng/l in the PDA group (P = 0.001) and 6 months after closure measured 78.5 ng/l (P = NS). Patients differed from control subjects in indices of LV diastolic and systolic function at baseline, but by the end of follow-up, all these differences had disappeared. Even in the subgroup of patients with normal-sized LV at baseline, the LV end-diastolic volume decreased significantly during follow-up. (III): Before repair, the size and wall thickness of LV were higher in patients with CoA than in controls. Systolic blood pressure measured a median 123 mm Hg in patients before repair (P < 0.001) and 103 mm Hg one year thereafter, and 101 mm Hg in controls. The diameter of the coarctation segment measured a median 3.0 mm at baseline, and 7.9 at the 12-month (P = 0.006) follow-up. Thicknesses of the interventricular septum and posterior wall of the LV decreased after repair but increased to the initial level one year thereafter. The velocity time integrals of mitral inflow increased, but no changes were evident in LV dimensions or contractility. During follow-up, serum levels of natriuretic peptides decreased correlating with diastolic and systolic indices of LV function in 2D and 3D echocardiography. (IV): In 2D echocardiography, the interventricular septum and LV posterior wall were thicker, and velocity time integrals of mitral inflow shorter in patients with Mulibrey nanism than in controls. In 3D echocardiography, LV end-diastolic volume measured a median 51.9 (range 33.3 to 73.4) ml/m² in patients and 59.7 (range 37.6 to 87.6) ml/m² in controls (P = 0.040), and serum levels of ANPN and proBNP a median 0.54 (range 0.04 to 4.7) nmol/l and 289 (range 18 to 9170) ng/l, in patients and 0.28 (range 0.09 to 0.72) nmol/l (P < 0.001) and 54 (range 26 to 139) ng/l (P < 0.001) in controls. They correlated with several indices of diastolic LV function. Conclusions (I): During the one-year follow-up after the ASD closure, RV size decreased but did not normalize in all patients. The size of the LV normalized after ASD closure but the increase in LV size was slower in patients treated surgically than in those treated with the percutaneous technique. Serum levels of ANPN and proBNP were elevated prior to ASD closure but decreased thereafter to control levels in patients treated with the percutaneous technique but not in those treated surgically. (II): Changes in LV volume and function caused by PDA disappeared by 6 months after percutaneous closure. Even the children with normal-sized LV benefited from the procedure. (III): After repair of CoA, the RV size and the velocity time integrals of mitral inflow increased, and serum levels of natriuretic peptides decreased. Patients need close follow-up, despite cessation of LV pressure overload, since LV hypertrophy persisted even in normotensive patients with normal growth of the coarctation segment. (IV): In children with Mulibrey nanism, the LV wall was hypertrophied, with myocardial restriction and impairment of LV function. Significant correlations appeared between indices of LV function, size of the left atrium, and levels of natriuretic peptides, indicating that measurement of serum levels of natriuretic peptides can be used in the clinical follow-up of this patient group despite its dependence on loading conditions.
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Although prevention and early detection of the disease greatly improved over the past few years, lung cancer remains the leading cause of cancer deaths. In order to be able to treat a larger population, we are in urgent need for novel treatments. While it is known that DNA repair genes play a major role in the oncogenic transformation, they also represent a weakness of cancers that constitute a therapeutic opportunity. To identify novel DNA repair genes implicated in Lung cancers, we conducted an in silico investigation to identify genes co-regulated with two DNA repair factors, BRCA2 and hSSB1. This approach allowed for the identification of EXOSC4, a component of the RNA Exosome machinery, as a potential factor involved in the maintenance of genome stability and that is deregulated in lung cancer.
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The RAD51 paralogs XRCC3 and RAD51C have been implicated in homologous recombination (HR) and DNA damage responses. However, the molecular mechanism(s) by which these paralogs regulate HR and DNA damage signaling remains obscure. Here, we show that an SQ motif serine 225 in XRCC3 is phosphorylated by ATR kinase in an ATM signaling pathway. We find that RAD51C but not XRCC2 is essential for XRCC3 phosphorylation, and this modification follows end resection and is specific to S and G(2) phases. XRCC3 phosphorylation is required for chromatin loading of RAD51 and HR-mediated repair of double-strand breaks (DSBs). Notably, in response to DSBs, XRCC3 participates in the intra-S-phase checkpoint following its phosphorylation and in the G(2)/M checkpoint independently of its phosphorylation. Strikingly, we find that XRCC3 distinctly regulates recovery of stalled and collapsed replication forks such that phosphorylation is required for the HR-mediated recovery of collapsed replication forks but is dispensable for the restart of stalled replication forks. Together, these findings suggest that XRCC3 is a new player in the ATM/ATR-induced DNA damage responses to control checkpoint and HR-mediated repair.
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This is the River Ehen and Tributaries SSSI consultation Protocol for the Environment Agency with English Nature, produced in 1998. The Protocol is intended to provide for consistency of approach, to clarify responsibilities and help to streamline the statutory consultation and consenting procedures in which both organisations are involved. It provides guiding principles on the approach to management issues. Based on the operations likely to damage the special interest (OLDSI) which forms part of the SSSI notification, the protocol identified acceptable management activities which contribute to the special interest of the site and those which may adversely affect that interest. OLDSI includes activities such: land drainage consents, discharge consents, herbicides approvals, fish-stocking consents, fishing licences, abstraction and impoundment licences, consents to construct/test pump boreholes, integrated pollution Control Licences and Waste Management Licences, capital projects, flood defence maintenance works, water resources, fisheries, pollution control, ecology surveys and Recreation works.
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In this paper, the relationship between radiosensitivity, cell cycle alteration and the change of apoptosis in different human hepatoma cell lines irradiated by heavy ions were studied with the aim of building up the base data for clinical therapy. Exponentially growing hepatoma cell lines were irradiated by 80.55 MeV/u(12)C(6+) ions at a dose of 0 Gy, 0.5 Gy, 1 Gy, 2 Gy, 4 Gy and 8 Gy. The radiosensitivity was assessed by means of the colony-forming assay. The DNA content, the percentage of each cell-cycle phase and the apoptosis rate were obtained with flow cytometry methods. After the irradiation, the SF2 (survival fraction at 2 gray) of SMMC-7721 cells were evidently lower than that of HepG2 cells. The S phase arrest, G2/M phase arrest delay and the apoptosis in the two hepatoma cell lines varied with the increase of the dose and repair time. The heavy ions could obviously kill the human hepatoma cell lines. Compared to HepG2 cells, SMMC-7721 cells were more radiosensitive to C-12(6+) ions.
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Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM)+ data have been successfully employed in the field of mineral exploration to identify key minerals over arid and semi-arid terrains. However, redundant vegetation and cloud may seriously interfere with the discrimination of the minerals with diagnostic features. Therefore, in this study, we use masking technique to eliminate the negative influence of vegetation and cloud and Crosta technique to identify the diagnostic features of hydroxyl-minerals, carbonate-minerals and iron oxides. Then the anomalies were endowed with special colours and overlapped with the remote-sensing and geochemical data, overlaying images as remote-sensing anomalies. The mineral exploration work was carried through by synthetic analysis of the remote-sensing images, geochemical data and structures. Finally, areas with high correlation between the occurrence of hydrothermal alteration and presence of main faults and geochemical anomalies were considered as mineral exploration targets worthy of further detailed exploration programmes.
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Jean-Michel Damase (b.1928), Andre Jolivet (1905-1974), and Henri Tomasi (1901-1971) are three prominent French composers ofthe twentieth century. Tomasi won the Prix de Rome in 1927, and Damase won the Prix de Rome in 1947. All three composers were educated and lived in Paris around the same period; however, their musical styles are quite distinct. Most of Jolivet's compositions for flute are well known and are often selected as international competition repertoire. The compositions for flute by Damase and Tomasi are not as recognized as those of Jolivet, and most of their works for flute still have not been commercially recorded. The purpose of this dissertation is to provide a more comprehensive guide to the compositions for flute by Damase, Jolivet and Tomasi, and, in addition, to make the works ofDamase and Tomasi familiar to flutists. This dissertation will focus on the compositions ofDamase, Jolivet, and Tomasi for flute alone and those for flute and piano, written between 1928 and 1971 (1928 is the year Damase was born, and 1971 is the year that Tomasi died). Damase continues French romanticism, and his music is always playful, elegant, and accessible with rhythmic and harmonic surprises, but with an underlying complexity. His compositions for flute include three concertos, two double concertos, one flute solo work, and nine works for flute and piano. Jolivet's compositions make use of ancient rituals, incantations, and spirituality, as well as repeated phrases and single notes, irregular rhythmic patterns, dissonant effects, and rhythmic drive. He composed one flute concerto, three works for flute solo, and four works for flute and piano. Tomasi's compositions also continue French romanticism and contain melodies which often seem to tell a story, and which are not only full of flourishes and vitality, but are also delicate, colorful, and romantic. Virtuosic technical demand is another characteristic of his style. Tomasi composed three flute concertos, three works for solo flute, and one work for flute and piano. Appendix I is a list of the compositions for flute by Damase, Jolivet, and Tomasi, and Appendix II is a discography of their works.
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In the late nineteenth century, French composers such as Camille Saint- Saens, Cesar Franck, and Claude Debussy worked to elevate instrumental music in late-Romantic period France, creating symphonies, concertos, and chamber ensembles, including duo sonatas. These composers and followers like, Ernest Chausson and Guillaume Lekeu were all influenced by a particular violinist to whom they dedicated their compositions. The primary violinist who inspired these composers was Eugene Ysaye (1858-1931), a brilliant performer and composer. His freedom of expression motivated many prominent French composers to dedicate major works to him. For example, Debussy dedicated his string quartet to Ysaye, who established the Ysaye Quartet and premiered Debussy's composition. In 1886, Franck completed his sonata for violin and piano which he also dedicated to Ysaye. Fritz Kreisler (1875-1962), one of the most talented violinists of his era, had a relationship withYsaye that was quite special. They respected, supported, and befriended each other. To Ysaye, Kreisler dedicated his Recitativo and Scherzo. To Kreisler, Ysaye dedicated one ofhis celebrated Sonatas for Solo Violin. Pablo de Sarasate (1844-1908) was a magnificent Spanish violinist of the late nineteenth century, and his music and performances influenced many composers, especially Saint-Saens, who included Spanish gypsy fragments in his works. These motifs may found in his Havanaise, Introduction and Rondo Capriccioso and Violin Concerto No.3 which were dedicated to Sarasate. My goal for this dissertation project has been to find and present, in three recitals, works by French composers and also works by the violinists who inspired them. As a violinist, I have endeavored to understand the influence of the various violinists on these French composers and how that knowledge can inform my approach to performing these works. In my first recital, with pianist Soo Young Jung, I performed works by Saint-Saens, Ysaye and Sarasate. With pianist Sun Ha Yoon, I performed works by Ysaye, Debussy, Kreisler and Franck in my second recital. My third recital, again with pianist Sun Ha Yoon, featured works by Ysaye, Chausson, and Lekeu. All recitals were recorded and performed at the University ofMaryland, College Park.
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During the period of 1990-2005, American-born women composers have contributed significantly to the standard clarinet repertoire. Pioneering composers such as Joan Tower, Margaret Brouwer, and Libby Larsen have created staples for clarinet literature. Yet, there is very little scholarly research on women composers of clarinet music, most being concentrated on Joan Tower. Through my research, I have discovered over seventy-five works by more than fifty composers in the following genres: solo clarinet; clarinet and piano; clarinet and voice, with or without piano; and small chamber pieces for up to five players. This performance dissertation project consists of three recitals featuring solo and chamber works by nine living women composers, and program notes containing pertinent biographical and compositional information. My intent is to increase recognition women composers, both prominent and lesser known, who are writing high-quality, accessible clarinet literature. Each woman selected is making a full or partial living from the sales of her compositions, has received recognition through awards, commissions, grants, and frequent performances, and has composed works that are both performer and audience accessible. Recital 1: Trios for Clarinet, Violin, and Piano Commissioned by the Verdehr Trio and Composed by American-Born Women Composers. Composers: Jennifer Higdon, Joan Tower, Margaret Brouwer, and Libby Larsen. Recital II: Programmatic Clarinet Works by American-Born Women Composers. Composers: Andrea Clearfield, Stella Sung, and Karen Amrhein. Recital III: Works for Solo Clarinet, Clarinet and Piano, and Clarinet Concerto Genres by American-Born Women Composers. Composers: Persis Parshall Vehar, Jenni Brandon, Margaret Brouwer, and Libby Larsen.
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During Franz Schubert’s penultimate year of 1827, he produced two profoundly important and mature works that are the focus of this recording project. The works are, in chronological order: • Winterreise (cycle of 24 songs on the poetry of Wilhelm Müller, 1794-1827) • Piano Trio in Eb Major, Op. 100, D. 929 A unique feature of the project is to present Winterreise in two poetic orders: as traditionally performed and published by Schubert, and in the final ordering published by the poet. The program notes accompanying the dissertation’s three compact discs have extensive information as well as comparative tables of Müller’s and Schubert’s final ordering of the cycle. There are significant differences in ordering, and ultimately the listener will determine which is more dramatically satisfying. Dark melancholy is the central emotion in Winterreise, which Schubert composed at various times throughout 1827 in a mood of corresponding gloom and distress. By contrast, the summer and fall of that year produced, in quick succession, the two glowing and remarkable Piano Trios in Bb and Eb, the second of which is included on these compact discs. The contrast between the trios and Winterreise follows the outward circumstances of Schubert’s life and health, a pattern of sorrow and later consolation and elation. The sound recordings for this dissertation recording project are available on three compact discs that can be found in the Digital Repository at the University of Maryland (DRUM). Winterreise was recorded in August 2009, at the University of Baltimore recital hall in Baltimore, Maryland with University of Maryland Professor François Loup. The trio, recorded in live performance in Baltimore in the spring of 2010, features two members of the Baltimore Symphony Orchestra: Qing Li, B.S.O. principal second violin, and Bo Li, B.S.O. section cellist.
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Subteratogenic and other low-level chronic exposures to toxicant mixtures are an understudied threat to environmental and human health. It is especially important to understand the effects of these exposures for contaminants, such as polycyclic aromatic hydrocarbons (PAHs) a large group of more than 100 individual compounds, which are important environmental (including aquatic) contaminants. Aquatic sediments constitute a major sink for hydrophobic pollutants, and studies show PAHs can persist in sediments over time. Furthermore, estuarine systems (namely breeding grounds) are of particular concern, as they are highly impacted by a wide variety of pollutants, and estuarine fishes are often exposed to some of the highest levels of contaminants of any vertebrate taxon. Acute embryonic exposure to PAHs results in cardiac teratogenesis in fish, and early life exposure to certain individual PAHs and PAH mixtures cause heart alterations with decreased swimming capacity in adult fish. Consequently, the heart and cardiorespiratory system are thought to be targets of PAH mixture exposure. While many studies have investigated acute, teratogenic PAH exposures, few studies have longitudinally examined the impacts of subtle, subteratogenic PAH mixture exposures, which are arguably more broadly applicable to environmental contamination scenarios. The goal of this dissertation was to highlight the later-life consequences of early-life exposure to subteratogenic concentrations of a complex, environmentally relevant PAH mixture.
A unique population of Fundulus heteroclitus (the Atlantic killifish or mummichog, hereafter referred to as killifish), has adapted to creosote-based polycyclic aromatic hydrocarbons (PAHs) found at the Atlantic Wood Industries (AW) Superfund site in the southern branch of the Elizabeth River, VA, USA. This killifish population survives in a site heavily contaminated with a mixture of PAHs from former creosote operations. They have developed resistance to the acute toxicity and teratogenic effects caused by the mixture of PAHs in sediment from the site. The primary goal of this dissertation was to compare and contrast later-life outcomes of early-life, subteratogenic PAH mixture exposure in both the Atlantic Wood killifish (AW) and a naïve reference population of killifish from King’s Creek (KC; a relatively uncontaminated tributary of the Severn River, VA). Killifish from both populations were exposed to subteratogenic concentrations of a complex PAH-sediment extract, Elizabeth River Sediment Extract (ERSE), made by collecting sediment from the AW site. Fish were reared over a 5-month period in the laboratory, during which they were examined for a variety of molecular, physiological and behavioral responses.
The central aims of my dissertation were to determine alterations to embryonic gene expression, larval swimming activity, adult behavior, heart structure, enzyme activity, and swimming/cardiorespiratory performance following subteratogenic exposure to ERSE. I hypothesized that subteratogenic exposure to ERSE would impair cardiac ontogenic processes in a way that would be detectable via gene expression in embryos, and that the misregulation of cardiac genes would help to explain activity changes, behavioral deficits, and later-life swimming deficiencies. I also hypothesized that fish heart structure would be altered. In addition, I hypothesized that the AW killifish population would be resistant to developmental exposures and perform normally in later life challenges. To investigate these hypotheses, a series of experiments were carried out in PAH-adapted killifish from Elizabeth River and in reference killifish. As an ancillary project to the primary aims of the dissertation, I examined the toxicity of weaker aryl hydrocarbon receptor (AHR) agonists in combination with fluoranthene (FL), an inhibitor of cytochrome P4501A1 (CYP1A1). This side project was conducted in both Danio rerio (zebrafish) and the KC and AW killifish.
Embryonic gene expression was measured in both killifish populations over an ERSE dose response with multiple time points (12, 24, 48, and 144 hours post exposure). Genes known to play critical roles in cardiac structure/development, cardiac function, and angiogenesis were elevated, indicating cardiac damage and activation of cardiovascular repair mechanisms. These data helped to inform later-life swimming performance and cardiac histology studies. Behavior was assessed during light and dark cycles in larvae of both populations following developmental exposure to ERSE. While KC killifish showed activity differences following exposure, AW killifish showed no significant changes even at concentrations that would cause overt cardiac toxicity in KC killifish. Juvenile behavior experiments demonstrated hyperactivity following ERSE exposure in KC killifish, but no significant behavioral changes in AW killifish. Adult swimming performance via prolonged critical swimming capacity (Ucrit) demonstrated performance costs in the AW killifish. Furthermore, swimming performance decline was observed in KC killifish following exposure to increasing dilutions of ERSE. Lastly, cardiac histology suggested that early-life exposure to ERSE could result in cardiac structural alteration and extravasation of blood into the pericardial cavity.
Responses to AHR agonists resulted in a ranking of relative potency for agonists, and determined which agonists, when combined with FL, caused cardiac teratogenesis. These experiments showed interesting species differences for zebrafish and killifish. To probe mechanisms responsible for cardiotoxicity, a CYP1A-morpholino and a AHR2-morpholino were used to mimic FL effects or attempt to rescue cardiac deformities respectively. Findings suggested that the cardiac toxicity elicited by weak agonist + FL exposure was likely driven by AHR-independent mechanisms. These studies stand in contrast to previous research from our lab showing that moderate AHR agonist + FL caused cardiac toxicity that can be partially rescued by AHR-morpholino knockdown.
My findings will form better characterization of mechanisms of PAH toxicity, and advance our understanding of how subteratogenic mixtures of PAHs exert their toxic action in naïve killifish. Furthermore, these studies will provide a framework for investigating how subteratogenic exposures to PAH mixtures can impact aquatic organismal health and performance. Most importantly, these experiments have the potential to help inform risk assessment in fish, mammals, and potentially humans. Ultimately, this research will help protect populations exposed to subtle PAH-contamination.
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Improving the sustainability of the housing stock is a major challenge facing the UK social housing sector. UK social housing accounts for approximately 18% of total UK housing and generates maintenance costs in the region of 1.25 billion pounds per annum. The extent to which routine maintenance can be used as a vehicle to improve the overall sustainability (social, environmental and economic) of existing social housing is one focus of a 5 year EPSRC funded research programme. This paper reports the findings of a questionnaire survey examining current social housing maintenance practices and attitudes towards sustainability. The research found that, whilst the stock condition survey is the favoured format for determining maintenance need and economics the basis for priority setting; neither systematically addresses wider sustainability issues; and, whilst cost is a major barrier to more sustainable solutions being adopted, landlords are able and have the desire to improve their practices.
Resumo:
Presently the UK social housing stock accounts for approximately 18% of the total UK housing with maintenance costs in the region of £1.25 billion per annum. In terms of its impact on the environment, housing is generally responsible for approximately 27% of the UK’s CO2 emissions. The extent to which routine maintenance (planned preventative and responsive) can be used as a vehicle to improve the overall sustainability (social, environmental and economic) of existing social housing is one focus of a 5 year EPSRC funded research programme. This paper reports on the findings of a series of in-depth interviews with social housing providers examining current social housing maintenance practices and attitudes towards sustainability. This paper will report the initial findings of interviews and outline a new performance based multi-criteria maintenance model from which an AHP hierarchy will be presented, integrating the principles of sustainability into maintenance strategies