2,553 research outputs found
Impact of Information and Communication Technology (ICT) on construction projects
The changing face of construction projects has resulted in a movement towards the use of technology as a primary means of communication. The consequences of this rise in the use of information and communication technology (ICT) is a loss of interpersonal communication skills. A number of resulting issues within the human â electronic and human â human interfaces are identified in an attempt to define the efficiency of communication in projects. The research shows how ICT effects the social environment of construction project teams and the project outcome. The study seeks to confirm the need for further work in order to develop new forms of communication protocols and behaviour. An initial literature review was undertaken to develop a theoretical review of the impacts of ICT on construction project teams. This review identified a number of issues that were then tested in the field through an observation and two verification interviews. The research confirms the existence of tensions and conflicts in the human â electronic and human - human communication interfaces within the studies environment. It is proposed that the increasing use of ICT occur at the expense of soft system communication. The principal impact of this is a form of âhuman distractionâ which adversely affects the performance of project teams. There is limited theory exploring these issues that suggests the problems identified are not well understood and consequently indicates a gap in knowledge
Roughening of the (1+1) interfaces in two-component surface growth with an admixture of random deposition
We simulate competitive two-component growth on a one dimensional substrate
of sites. One component is a Poisson-type deposition that generates
Kardar-Parisi-Zhang (KPZ) correlations. The other is random deposition (RD). We
derive the universal scaling function of the interface width for this model and
show that the RD admixture acts as a dilatation mechanism to the fundamental
time and height scales, but leaves the KPZ correlations intact. This
observation is generalized to other growth models. It is shown that the
flat-substrate initial condition is responsible for the existence of an early
non-scaling phase in the interface evolution. The length of this initial phase
is a non-universal parameter, but its presence is universal. In application to
parallel and distributed computations, the important consequence of the derived
scaling is the existence of the upper bound for the desynchronization in a
conservative update algorithm for parallel discrete-event simulations. It is
shown that such algorithms are generally scalable in a ring communication
topology.Comment: 16 pages, 16 figures, 77 reference
Global Environmental Flow Information for the Sustainable Development Goals
Environmental flows (EF) are an important component of Goal 6 (the âwater goalâ) of the Sustainable Development Goals (SDGs). Yet, many countries still do not have well-defined criteria on how to define EF. In this study, we bring together the International Water Management Instituteâs (IWMIâs) expertise and previous research in this area to develop a new methodology to quantify EF at a global scale. EF are developed for grids (0.1 degree spatial resolution) for different levels of health (defined as environmental management classes [EMCs]) of river sections. Additionally, EF have been separated into surface water and groundwater components, which also helps in developing sustainable groundwater abstraction (SGWA) limits. An online tool has been developed to calculate EF and SGWA in any area of interest
Cooling Flows and Metallicity Gradients in Clusters of Galaxies
The X-ray emission by hot gas at the centers of clusters of galaxies is
commonly modeled assuming the existence of steady-state, inhomogeneous cooling
flows. We derive the metallicity profiles of the intracluster medium expected
from such models. The inflowing gas is chemically enriched by type Ia
supernovae and stellar mass loss in the outer parts of the central galaxy,
which may give rise to a substantial metallicity gradient. The amplitude of the
expected metallicity enhancement towards the cluster center is proportional to
the ratio of the central galaxy luminosity to the mass inflow rate. The
metallicity of the hotter phases is expected to be higher than that of the
colder, denser phases. The metallicity profile expected for the Centaurus
cluster is in good agreement with the metallicity gradient recently inferred
from ASCA measurements (Fukazawa et al. 1994). However, current data do not
rule out alternative models where cooling is balanced by some heat source. The
metallicity gradient does not need to be present in all clusters, depending on
the recent merging history of the gas around the central cluster galaxy, and on
the ratio of the stellar mass in the central galaxy to the gas mass in the
cooling flow.Comment: uuencoded postscript, 8 pages of text + 2 figures, accepted by The
Astrophysical Journal (Letters
Polymeric additives to enhance the functional properties of calcium phosphate cements
The vast majority of materials used in bone tissue engineering and regenerative medicine are based on calcium phosphates due to their similarity with the mineral phase of natural bone. Among them, calcium phosphate cements, which are composed of a powder and a liquid that are mixed to obtain a moldable paste, are widely used. These calcium phosphate cement pastes can be injected using minimally invasive surgery and adapt to the shape of the defect, resulting in an entangled network of calcium phosphate crystals. Adding an organic phase to the calcium phosphate cement formulation is a very powerful strategy to enhance some of the properties of these materials. Adding some water-soluble biocompatible polymers in the calcium phosphate cement liquid or powder phase improves physicochemical and mechanical properties, such as injectability, cohesion, and toughness. Moreover, adding specific polymers can enhance the biological response and the resorption rate of the material. The goal of this study is to overview the most relevant advances in this field, focusing on the different types of polymers that have been used to enhance specific calcium phosphate cement properties
Calcareous Nannofossils and Paleoclimatic Evolution Across the Eocene-Oligocene Transition at IODP Site U1509, Tasman Sea, Southwest Pacific Ocean
The EoceneâOligocene transition (EOT; âŒ34 Ma) was one of the most prominent global cooling events of the Cenozoic, coincident with the emergence of continentalâscale iceâsheets on Antarctica. Calcareous nannoplankton experienced significant assemblage turnover at a time of longâterm surface ocean cooling and trophic conditions, suggesting causeâeffect relationships between Antarctic glaciation, broader climate changes, and the response of phytoplankton communities. To better evaluate the timing and nature of these relationships, we generated calcareous nannofossil and geochemical data sets (ÎŽ18O, ÎŽ13C and %CaCO3) over a âŒ5 Myr stratigraphic interval recovered across the EOT from IODP Site U1509 in the Tasman Sea, South Pacific Ocean. Based on trends observed in the calcareous nannofossil assemblages, there was an overall decline of warmâoligotrophic communities, with a shift toward taxa better adapted to cooler more eutrophic conditions. Assemblage changes indicate four distinct phases caused by temperature decrease and variations in paleocurrents: late Eocene warmâoligotrophic phase, precursor diversityâdecrease phase, early Oligocene coldâeutrophic phase, and a steadyâstate cosmopolitan phase. The most prominent shift in the assemblages occurred during the âŒ550 kyrâlong precursor diversityâdecrease phase, which has relatively high bulk ÎŽ18O and %CaCO3 values, and predates the phase of maximum glacial expansion (Earliest Oligocene Glacial MaximumâEOGM)
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Mental health in UK Biobank - development, implementation and results from an online questionnaire completed by 157 366 participants: a reanalysis
Background
UK Biobank is a well-characterised cohort of over 500 000 participants including genetics, environmental data and imaging. An online mental health questionnaire was designed for UK Biobank participants to expand its potential.
Aims
Describe the development, implementation and results of this questionnaire.
Method
An expert working group designed the questionnaire, using established measures where possible, and consulting a patient group. Operational criteria were agreed for defining likely disorder and risk states, including lifetime depression, mania/hypomania, generalised anxiety disorder, unusual experiences and self-harm, and current post-traumatic stress and hazardous/harmful alcohol use.
Results
A total of 157 366 completed online questionnaires were available by August 2017. Participants were aged 45â82 (53% were â„65 years) and 57% women. Comparison of self-reported diagnosed mental disorder with a contemporary study shows a similar prevalence, despite respondents being of higher average socioeconomic status. Lifetime depression was a common finding, with 24% (37 434) of participants meeting criteria and current hazardous/harmful alcohol use criteria were met by 21% (32 602), whereas other criteria were met by less than 8% of the participants. There was extensive comorbidity among the syndromes. Mental disorders were associated with a high neuroticism score, adverse life events and long-term illness; addiction and bipolar affective disorder in particular were associated with measures of deprivation.
Conclusions
The UK Biobank questionnaire represents a very large mental health survey in itself, and the results presented here show high face validity, although caution is needed because of selection bias. Built into UK Biobank, these data intersect with other health data to offer unparalleled potential for crosscutting biomedical research involving mental health
Hubble Space Telescope Observations of an Outer Field in Omega Centauri: A Definitive Helium Abundance
We revisit the problem of the split main sequence (MS) of the globular
cluster omega Centauri, and report the results of two-epoch Hubble Space
Telescope observations of an outer field, for which proper motions give us a
pure sample of cluster members, and an improved separation of the two branches
of the main sequence. Using a new set of stellar models covering a grid of
values of helium and metallicity, we find that the best possible estimate of
the helium abundance of the bluer branch of the MS is Y = 0.39 +/- 0.02. For
the cluster center we apply new techniques to old observations: we use indices
of photometric quality to select a high-quality sample of stars, which we also
correct for differential reddening. We then superpose the color-magnitude
diagram of the outer field on that of the cluster center, and suggest a
connection of the bluer branch of the MS with one of the more prominent among
the many sequences in the subgiant region. We also report a group of undoubted
cluster members that are well to the red of the lower MS.Comment: 26 pages, 10 figures (4 in low resolution. AJ accepted on March 21,
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