2,844 research outputs found
Construction informatics in Turkey: strategic role of ICT and future research directions
Construction Informatics deals with subjects ranging from strategic management of ICTs to interoperability and information integration in the construction industry. Studies on defining research directions for Construction Informatics have a history over 20 years. The recent studies in the area highlight the priority themes for Construction Informatics research as interoperability, collaboration support, intelligent sites and knowledge sharing. In parallel, today it is widely accepted in the Architecture/Engineering/Construction (AEC) industry that ICT is becoming a strategic asset for any organisation to deliver business improvement and achieve sustainable competitive advantage. However, traditionally the AEC industry has approached investing in ICT with a lack of strategic focus and low level of priority to the business. This paper presents a recent study from Turkey that is focused on two themes. The first theme investigates the strategic role of ICT implementations from an industrial perspective, and explores if organisations within the AEC industry view ICT as a strategic resource for their business practice. The second theme investigates the âperspective of academiaâ in terms of future research directions of Construction Informatics. The results of the industrial study indicates that ICT is seen as a value-adding resource, but a shift towards the recognition of the importance of ICT in terms of value adding in winning work and achieving strategic competitive advantage is observed. On the other hand, ICT Training is found to be the theme of highest priority from the academia point of view
Attraction between like-charged colloidal particles induced by a surface a density - functional analysis
We show that the first non-linear correction to the linearised
Poisson-Boltzman n (or DLVO) theory of effective pair interactions between
charge-stabilised, co lloidal particles near a charged wall leads to an
attractive component of entro pic origin. The position and depth of the
potential compare favourably with rec ent experimental measurementsComment: 12 pages including 2 figures. submitted to physical review letter
A General Precipitation-Limited L_X-T-R Relation Among Early-Type Galaxies
The relation between X-ray luminosity (L_X) and ambient gas temperature (T)
among massive galactic systems is an important cornerstone of both
observational cosmology and galaxy-evolution modeling. In the most massive
galaxy clusters, the relation is determined primarily by cosmological structure
formation. In less massive systems, it primarily reflects the feedback response
to radiative cooling of circumgalactic gas. Here we present a simple but
powerful model for the L_X-T relation as a function of physical aperture R
within which those measurements are made. The model is based on the
precipitation framework for AGN feedback and assumes that the circumgalactic
medium is precipitation-regulated at small radii and limited by cosmological
structure formation at large radii. We compare this model with many different
data sets and show that it successfully reproduces the slope and upper envelope
of the L_X-T-R relation over the temperature range from ~0.2 keV through >10
keV. Our findings strongly suggest that the feedback mechanisms responsible for
regulating star formation in individual massive galaxies have much in common
with the precipitation-triggered feedback that appears to regulate
galaxy-cluster cores.Comment: Submitted to ApJ, 9 pages, 3 figures (v2 fixes a few small typos
Differential modulation of annexin I binding sites on monocytes and neutrophils.
Specific binding sites for the anti-inflammatory protein annexin I have been detected on the surface of human monocytes and polymorphonuclear leukocytes (PMN). These binding sites are proteinaceous in nature and are sensitive to cleavage by the proteolytic enzymes trypsin, collagenase, elastase and cathepsin G. When monocytes and PMN were isolated independently from peripheral blood, only the monocytes exhibited constitutive annexin I binding. However PMN acquired the capacity to bind annexin I following co-culture with monocytes. PMN incubation with sodium azide, but not protease inhibitors, partially blocked this process. A similar increase in annexin I binding capacity was also detected in PMN following adhesion to endothelial monolayers. We propose that a juxtacrine activation rather than a cleavage-mediated transfer is involved in this process. Removal of annexin I binding sites from monocytes with elastase rendered monocytes functionally insensitive to full length annexin I or to the annexin I-derived pharmacophore, peptide Ac2-26, assessed as suppression of the respiratory burst. These data indicate that the annexin I binding site on phagocytic cells may have an important function in the feedback control of the inflammatory response and their loss through cleavage could potentiate such responses
Is it possible to increase the sustainability of arable and ruminant agriculture by reducing inputs?
Until recently, agricultural production was optimised almost exclusively for profit but now farming is under pressure to meet environmental targets. A method is presented and applied for optimising the sustainability of agricultural production systems in terms of both economics and the environment. Components of the agricultural production chain are analysed using environmental life-cycle assessment (LCA) and a financial value attributed to the resources consumed and burden imposed on the environment by agriculture, as well as to the products. The sum of the outputs is weighed against the inputs and the system considered sustainable if the value of the outputs exceeds those of the inputs. If this ratio is plotted against the sum of inputs for all levels of input, a diminishing returns curve should result and the optimum level of sustainability is located at the maximum of the curve. Data were taken from standard economic almanacs and from published LCA reports on the extent of consumption and environmental burdens resulting from farming in the UK. Land-use is valued using the concept of ecosystem services. Our analysis suggests that agricultural systems are sustainable at rates of production close to current levels practiced in the UK. Extensification of farming, which is thought to favour non-food ecosystem services, requires more land to produce the same amount of food. The loss of ecosystem services hitherto provided by natural land brought into production is greater than that which can be provided by land now under extensive farming. This loss of ecosystem service is large in comparison to the benefit of a reduction in emission of nutrients and pesticides. However, food production is essential, so the coupling of subsidies that represent a relatively large component of the economic output in EU farming, with measures to reduce pollution are well-aimed. Measures to ensure that as little extra land is brought into production as possible or that marginal land is allowed to revert to nature would seem to be equally well-aimed, even if this required more intensive use of productive areas. We conclude that current arable farming in the EU is sustainable with either realistic prices for products or some degree of subsidy and that productivity per unit area of land and greenhouse gas emission (subsuming primary energy consumption) are the most important pressures on the sustainability of farming
Effect of many-body interactions on the solid-liquid phase-behavior of charge-stabilized colloidal suspensions
The solid-liquid phase-diagram of charge-stabilized colloidal suspensions is
calculated using a technique that combines a continuous Poisson-Boltzmann
description for the microscopic electrolyte ions with a molecular-dynamics
simulation for the macroionic colloidal spheres. While correlations between the
microions are neglected in this approach, many-body interactions between the
colloids are fully included. The solid-liquid transition is determined at a
high colloid volume fraction where many-body interactions are expected to be
strong. With a view to the Derjaguin-Landau-Verwey-Overbeek theory predicting
that colloids interact via Yukawa pair-potentials, we compare our results with
the phase diagram of a simple Yukawa liquid. Good agreement is found at high
salt conditions, while at low ionic strength considerable deviations are
observed. By calculating effective colloid-colloid pair-interactions it is
demonstrated that these differences are due to many-body interactions. We
suggest a density-dependent pair-potential in the form of a truncated Yukawa
potential, and show that it offers a considerably improved description of the
solid-liquid phase-behavior of concentrated colloidal suspensions
Deletion of p38α MAPK in Microglia Blunts Trauma-Induced Inflammatory Responses in Mice
Traumatic brain injury (TBI) is a significant cause of morbidity and mortality in the USA and other developed countries worldwide. Following the initial mechanical insult, the brainâs primary innate immune effector, microglia, initiate inflammatory signaling cascades and pathophysiological responses that can lead to chronic neuroinflammation and neurodegenerative sequelae. The p38α MAPK signaling pathway in microglia is a key contributor to inflammatory responses to diverse disease-relevant stressors and injury conditions. Therefore, we tested here whether microglia p38α contributes to acute and persistent inflammatory responses induced by a focal TBI. We generated conditional cell-specific knockout of p38α in microglia using a CX3CR1 Cre-lox system, subjected the p38α knockout and wild-type mice to a controlled cortical impact TBI, and measured inflammatory responses at acute (1-day) and subacute (7-day) post-injury time points. We found that deletion of p38α in microglia only was sufficient to attenuate multiple pro-inflammatory responses following TBI, notably reducing pro-inflammatory cytokine/chemokine production and recruitment of inflammatory monocytes into the brain and preventing the persistent microglial morphological activation. These data provide strong evidence supporting a role for microglial p38α in propagation of a chronic and potentially neurotoxic pro-inflammatory environment in the brain following TBI
Managing information flow and design processes to reduce design risks in offsite construction projects
© 2019, Emerald Publishing Limited. Purpose: Following the increasing need for faster construction, improved quality and evidence value propositions, offsite construction is increasingly being proffered as a viable contender to âtraditionalâ construction approaches. However, whilst evidence supports the move towards offsite, its uptake has been lower than expected. Whilst the precise reasons for this seem to be influenced by a number of issues, including contextual drivers and market maturity; some project stakeholders also view offsite as carrying greater risks. The purpose of this paper is to report on the quality of information flow, in particular, the impact and influence of this on design risks in offsite construction projects. Design/methodology/approach: An existing design risk framework is used as the point of departure for this research. This is further expanded into a specific model for evaluating offsite construction projects design risks, the rubrics of which were informed by two case studies of offsite construction projects in Australia and the UK analysed with a process-tracing technique. Whilst these cases were geographically separated, the constructs were aligned to uncover fundamental design information requirements and concomitant risks associated with offsite. Findings: The findings of the research reported in this paper include the crucial information feeding into the design process emanating from the lifecycle of offsite construction projects, namely, design, offsite (manufacturing), handling and transporting, site works and installation and also occupancy. These are contextualised within the four categories, namely, client requirements, project requirements, regulation aspects and social aspects and the final outcomes were summarised into a holistic diagram. Originality/value: Given that the offsite construction has shifted the working paradigm into assigning a significant level of efforts and emphasis at the front end of the construction projects, the importance of its design process and hence design risks management has gone up significantly in construction projects delivered using this technique. This research and paper contributes significantly to the built environment domain by identifying the crucial aspects along the project lifecycle to be considered to minimise the potential occurrence of design risks and hence increasing the confidence of project stakeholders in adopting offsite construction techniques in their projects.Published versio
Characterizing the far-infrared properties of distant X-ray detected AGNs: evidence for evolution in the infraredâX-ray luminosity ratio
We investigate the far-infrared (FIR) properties of X-ray sources detected in the Chandra Deep Field-South (CDF-S) survey using the ultradeep 70 and 24 ÎŒm Spitzer observations taken in this field. Since only 30 (i.e. â 10 per cent) of the 266 X-ray sources in the region of the 70 ÎŒm observations are detected at 70 ÎŒm, we rely on stacking analyses of the 70 ÎŒm data to characterize the average 70 ÎŒm properties of the X-ray sources as a function of redshift, X-ray luminosity and X-ray absorption. Using Spitzer-IRS data of the Swift-Burst Alert Telescope (BAT) sample of z â 0 active galactic nuclei (AGNs), we show that the 70/24 ÎŒm flux ratio can distinguish between AGN-dominated and starburst-dominated systems out to z â 1.5 . Among the X-ray sources detected at 70 ÎŒm, we note a large scatter in the observed 70/24 ÎŒm flux ratios, spanning almost a factor of 10 at similar redshifts, irrespective of object classification, suggesting a range of AGN:starburst ratios. From stacking analyses we find that the average observed 70/24 ÎŒm flux ratios of AGNs out to an average redshift of 1.5 are similar to z â 0 AGNs with similar X-ray luminosities (L_X = 10^(42-44) erg s^(â1)) and absorbing column densities (N_H †10^(23) cm^(â2)) . Furthermore, both high-redshift and z â 0 AGNs follow the same tendency towards warmer 70/24 ÎŒm colours with increasing X-ray luminosity (LX). From analyses of the Swift-BAT sample of z â 0 AGNs, we note that the 70 ÎŒm flux can be used to determine the IR (8â1000 ÎŒm) luminosities of high-redshift AGNs. We use this information to show that L_X = 10^(42-43) erg s^(â1) AGNs at high redshifts (z = 1â2) have IR to X-ray luminosity ratios (L_(IR)/L_X) that are, on average, 4.7^(+10.2)_(â2.0) and 12.7+7.1â2.6 times higher than AGNs with similar X-ray luminosities at z = 0.5â1 and â0, respectively. By comparison, we find that the L_(IR)/L_X ratios of L_X= 10^(43-44) erg s^(â1) AGNs remain largely unchanged across this same redshift interval. We explore the consequences that these results may have on the identification of distant, potentially Compton-thick AGNs using L_(IR)/L_X ratios. In addition, we discuss possible scenarios for the observed increase in the L_(IR)/L_X ratio with redshift, including changes in the dust covering factor of AGNs and/or the star formation rates of their host galaxies. Finally, we show how deep observations to be undertaken by the Herschel Space Observatory will enable us to discriminate between these proposed scenarios and also identify Compton-thick AGNs at high redshifts
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