38 resultados para Metal in the architecture


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Zinc (Zn) and cadmium (Cd) hyperaccumulation may have evolved twice in the Brassicaceae, in Arabidopsis halleri and in the Noccaea genus. Tandem gene duplication and deregulated expression of the Zn transporter, HMA4, has previously been linked to Zn/Cd hyperaccumulation in A. halleri. Here, we tested the hypothesis that tandem duplication and deregulation of HMA4 expression also occurs in Noccaea. A Noccaea caerulescens genomic library was generated, containing 36,864 fosmid pCC1FOS (TM) clones with insert sizes similar to 20-40 kbp, and screened with a PCR-generated HMA4 genomic probe. Gene copy number within the genome was estimated through DNA fingerprinting and pooled fosmid pyrosequencing. Gene copy numbers within individual clones was determined by PCR analyses with novel locus specific primers. Entire fosmids were then sequenced individually and reads equivalent to 20-fold coverage were assembled to generate complete whole contigs. Four tandem HMA4 repeats were identified in a contiguous sequence of 101,480 bp based on sequence overlap identities. These were flanked by regions syntenous with up and downstream regions of AtHMA4 in Arabidopsis thaliana. Promoter-reporter beta-glucuronidase (GUS) fusion analysis of a NcHMA4 in A. thaliana revealed deregulated expression in roots and shoots, analogous to AhHMA4 promoters, but distinct from AtHMA4 expression which localised to the root vascular tissue. This remarkable consistency in tandem duplication and deregulated expression of metal transport genes between N. caerulescens and A. halleri, which last shared a common ancestor > 40 mya, provides intriguing evidence that parallel evolutionary pathways may underlie Zn/Cd hyperaccumulation in Brassicaceae.

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Students in the architecture, engineering, and construction disciplines are often challenged with visualizing and understanding the complex spatial and temporal relationships involved in designing and constructing three-dimensional (3D) structures. An evolving body of research traces the use of educational computer simulations to enhance student learning experiences through testing real-world scenarios and the development of student decision-making skills. Ongoing research at Pennsylvania State University aims to improve engineering education in construction through interactive construction project learning applications in an immersive virtual reality environment. This paper describes the first- and second-generation development of the Virtual Construction Simulator (VCS), a tool that enables students to simultaneously create and review construction schedules through 3D model interaction. The educational value and utility of VCS was assessed through surveys, focus group interviews, and a student exercise conducted in a construction management class. Results revealed VCS is a valuable and effective four-dimensional (4D) model creation and schedule review application that fosters collaborative work and greater student task focus. This paper concludes with a discussion of the findings and the future development steps of the VCS educational simulation

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Project management (PM) is a globally recognized discipline and has been widely adopted within the construction industry. Despite advancements in the PM discipline, the ineffective traditional management system, typical of the non-executive PM structure, is still widely used in the Nigerian construction industry. The aim of this paper is thus to explore the challenges facing the adoption of the executive PM structure in Nigeria. The paper first assesses the level of growth of PM in Nigeria using UK best practices as a benchmark and identifies the key PM characteristics in the two countries. Focus group interviews were used to collect the primary data for the study and content analysis was used to present the results in a thematic format. The study revealed the key barriers to the adoption of an executive PM structure in Nigeria as a lack of proper awareness, unfavorable policies, skill shortages, the traditional culture of stakeholders and the absence of a regulatory body. It is recommended that the government, as a major player/client in the Nigerian construction industry, should lead the campaign to change the traditional industry approach to project management. This is necessary if construction stakeholders in Nigeria are to be educated and encouraged towards adopting and putting into practice effective PM.

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The effects of varying the alkali metal cation in the high-temperature nucleophilic synthesis of a semi-crystalline, aromatic poly(ether ketone) have been systematically investigated, and striking variations in the sequence-distributions and thermal characteristics of the resulting polymers were found. Polycondensation of 4,4'-dihydroxybenzophenone with 1,3-bis(4-fluorobenzoyl)benzene in diphenylsulfone as solvent, in the presence of an alkali metal carbonate M2CO3 (M= Li, Na, K, or Rb) as base, affords a range of different polymers that vary in the distribution pattern of 2-ring and 3-ring monomer units along the chain. Lithium carbonate gives an essentially alternating and highly crystalline polymer, but the degree of sequence-randomisation increases progressively as the alkali metal series is descended, with rubidium carbonate giving a fully random and non-thermally-crystallisable polymer. Randomisation during polycondensation is shown to result from reversible cleavage of the ether linkages in the polymer by fluoride ions, and an isolated sample of alternating-sequence polymer is thus converted to a fully randomised material on heating with rubidium fluoride.

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This study examines the creation of the urban kommuna (commune) and the ideals that stimulated this social phenomenon – the kommuna impulse of the nascent Soviet state. Collective idealism affected Soviet housing, architecture and even urban planning, but little is known of social experiments in commune‐ism. As a result, these collective cells have been dismissed as utopian anomalies or the product of a housing shortage. Here it is argued that these discursive assessments are unsatisfactory and isolated from the historical narrative. While utopian ideals and domestic necessity were central to the formation of collective living, the kommuna was also involved in an active discourse with collectivism and socialist ideology. The kommuna cell was a dynamic entity that required considerable formative planning. The activists who forged these cells – the self‐identified ‘communards’ – turned their everyday domestic life into a socialist battleground, in which they struggled with the key debates of the early Soviet state. This article examines the communard as a social activist in order to better understand this phenomenon. It clarifies the coexistence of ideological and idealist trends among Soviet youth with practical contingencies for socialism. Furthermore, it reveals the process by which the kommuna impulse and these contingencies developed throughout the 1920s and early 1930s.

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Corporates are entering the brave new world of the internet and digitization without much regard for the fine print of a growing regulation regime. More traditional outsourcing arrangements are already falling foul of the regulators as rules and supervision intensifies. Furthermore, ‘shadow IT’ is proliferating as the attractions of SaaS, mobile, cloud services, social media, and endless new ‘apps’ drive usage outside corporate IT. Initial cost-benefit analyses of the Cloud make such arrangements look immediately attractive but losing control of architecture, security, applications and deployment can have far reaching and damaging regulatory consequences. From research in financial services, this paper details the increasing body of regulations, their inherent risks for businesses and how the dangers can be pre-empted and managed. We then delineate a model for managing these risks specifically focused on investigating, strategizing and governing outsourcing arrangements and related regulatory obligations