A great many of today’s construction projects are characterized by high levels of dynamics, namely, the combined effect of complexity, uncertainty, and speed. Managing projects under such conditions is difficult and challenging, and the question is asked: How do managers do it? Aspiring to answer this question, ten excellent on-site construction project managers were systematically observed during one workweek each, within an extensive study that examined their performance in their dynamic management environments. The structured observation and documentation and the analysis that followed them enabled us to characterize the managers’ work and exposed their unique modes of operation through which they consistently excel in their work. Among many aspects addressed by the said study, this paper focuses on communication and, using various measures, examines the intensiveness and extensiveness of communication performed by the PMs in the broad context of their work. The study found that the on-site construction PMs were strongly oriented toward verbal communication of information (during nearly 80% of their activities and time); they spent a major portion of their workdays in meetings (during 60% of their activities, and of which nearly 80% were unplanned); and they showed clear preference for interacting informally with no more than one or two other persons (during 93% of their activities and 88% of the time). The unique knowledge base resulting from this study constitutes a potential contribution for practitioners who are required to function in similar dynamic work environments, as well as for students, teachers, and researchers of construction management. 相似文献
The purpose of this article is to provide supervisors with postdisaster strategies for promoting supervisee self-care. These recommendations are based on relevant disaster mental health and supervision research along with the authors' experiences of supervising and teaching in a university setting following Hurricane Katrina in South Mississippi. Supervisory examples from the authors' hurricane experiences are also provided to highlight each recommendation. A supervisee self-care tool is offered to aid supervisors in their efforts to help supervisees develop positive coping responses in the event of a disaster. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The environmental characteristics of the brine and its impacts on the marine environment were always the “backyard” and the less concern while planning and operating RO desalination plants. The lack of drinking water in Israel made desalination a national goal. The first huge RO plant was initially operated in Israel on 2005 — 100 Mm3/y and by the end of 2010 305 Mm3/y potable water expected to be produced. Construction and installation of desalination plants requires applying suitable environmental solutions for protecting and preserving the marine and coastal environment from ruin or deterioration.
The Israeli environmental legislation is described including the marine environmental policy and regulations as well as the acquired operational experience during the last two years. Results from the first year of operation and monitoring are shown along with the new appearance of the red phenomenon discharge of VID desalination plant in Ashkelon.
The environmental policy based on the precautionary principle is performed and includes environmental requirements and guidelines for pretreatment, discharge composition, planning marine outfall, background and compliance marine monitoring program and discharge quality standards. 相似文献
Precursor nanoparticles that form spontaneously on hydrolysis of tetraethylorthosilicate in aqueous solutions of tetrapropylammonium (TPA) hydroxide evolve to TPA-silicalite-1, a molecular-sieve crystal that serves as a model for the self-assembly of porous inorganic materials in the presence of organic structure-directing agents. The structure and role of these nanoparticles are of practical significance for the fabrication of hierarchically ordered porous materials and molecular-sieve films, but still remain elusive. Here we show experimental findings of nanoparticle and crystal evolution during room-temperature ageing of the aqueous suspensions that suggest growth by aggregation of nanoparticles. A kinetic mechanism suggests that the precursor nanoparticle population is distributed, and that the 5-nm building units contributing most to aggregation only exist as an intermediate small fraction. The proposed oriented-aggregation mechanism should lead to strategies for isolating or enhancing the concentration of crystal-like nanoparticles. 相似文献
MiRNAs are important epigenetic players with tissue- and disease-specific effects. In this study, our aim was to investigate the putative differential expression of miRNAs in adrenal tissues from different forms of Cushing’s syndrome (CS). For this, miRNA-based next-generation sequencing was performed in adrenal tissues taken from patients with ACTH-independent cortisol-producing adrenocortical adenomas (CPA), from patients with ACTH-dependent pituitary Cushing’s disease (CD) after bilateral adrenalectomy, and from control subjects. A confirmatory QPCR was also performed in adrenals from patients with other CS subtypes, such as primary bilateral macronodular hyperplasia and ectopic CS. Sequencing revealed significant differences in the miRNA profiles of CD and CPA. QPCR revealed the upregulated expression of miR-1247-5p in CPA and PBMAH (log2 fold change > 2.5, p < 0.05). MiR-379-5p was found to be upregulated in PBMAH and CD (log2 fold change > 1.8, p < 0.05). Analyses of miR-1247-5p and miR-379-5p expression in the adrenals of mice which had been exposed to short-term ACTH stimulation showed no influence on the adrenal miRNA expression profiles. For miRNA-specific target prediction, RNA-seq data from the adrenals of CPA, PBMAH, and control samples were analyzed with different bioinformatic platforms. The analyses revealed that both miR-1247-5p and miR-379-5p target specific genes in the WNT signaling pathway. In conclusion, this study identified distinct adrenal miRNAs as being associated with CS subtypes. 相似文献
The problem of answering queries using views is to find efficient methods of answering a query using a set of previously
defined materialized views over the database, rather than accessing the database relations. The problem has recently received
significant attention because of its relevance to a wide variety of data management problems. In query optimization, finding
a rewriting of a query using a set of materialized views can yield a more efficient query execution plan. To support the separation
of the logical and physical views of data, a storage schema can be described using views over the logical schema. As a result,
finding a query execution plan that accesses the storage amounts to solving the problem of answering queries using views.
Finally, the problem arises in data integration systems, where data sources can be described as precomputed views over a mediated
schema. This article surveys the state of the art on the problem of answering queries using views, and synthesizes the disparate
works into a coherent framework. We describe the different applications of the problem, the algorithms proposed to solve it
and the relevant theoretical results.
Received: 1 August 1999 / Accepted: 23 March 2001 Published online: 6 September 2001 相似文献