241 research outputs found
Constructing the future of the city centre : realizing visions
As cities are being asked to transition to a new future shaped by significant social, economic and environmental challenges, renewed attention is being given to the urban development process, and on how this process has to be more inclusive, and the outcomes more coherent. With past notions of masterplans as a single, fixed visionary document being replaced with guiding strategies, open to interpretation, there is a greater need for different disciplines to engage together throughout the development process. This paper explores opportunities and needs for construction management to be more actively involved in the reshaping of the city centre, from the envisioning of its future to the realization of change. Through the lens of the process of change in four city centres across the world, this paper outlines how discussing construction management could beneficially engage with other urban disciplines to create a shared vision for centres as part of local governance. It argues for construction management adopt a wider spatial and temporal perspective that looks beyond specific buildings, site and projects to situate development in the urban and regional systems and to help be part of the envisioning process. Along with more critical engagement in the policy, design and construction processes for construction management, the paper points to a need for more local sensitivity and adaptation including an appreciation of the contribution of public spaces and a different approach to urban development if the city centre is to be more sustainable in future
Bacterioplankton dynamics within a large anthropogenically impacted urban estuary
© 2016 Jeffries, Schmitz Fontes, Harrison, Van-Dongen-Vogels, Eyre, Ralph and Seymour. The abundant and diverse microorganisms that inhabit aquatic systems are both determinants and indicators of aquatic health, providing essential ecosystem services such as nutrient cycling but also causing harmful blooms and disease in impacted habitats. Estuaries are among the most urbanized coastal ecosystems and as a consequence experience substantial environmental pressures, providing ideal systems to study the influence of anthropogenic inputs on microbial ecology. Here we use the highly urbanized Sydney Harbor, Australia, as a model system to investigate shifts in microbial community composition and function along natural and anthopogenic physicochemical gradients, driven by stormwater inflows, tidal flushing and the input of contaminants and both naturally and anthropogenically derived nutrients. Using a combination of amplicon sequencing of the 16S rRNA gene and shotgun metagenomics, we observed strong patterns in microbial biogeography across the estuary during two periods: one of high and another of low rainfall. These patterns were driven by shifts in nutrient concentration and dissolved oxygen leading to a partitioning of microbial community composition in different areas of the harbor with different nutrient regimes. Patterns in bacterial composition were related to shifts in the abundance of Rhodobacteraceae, Flavobacteriaceae, Microbacteriaceae, Halomonadaceae, Acidomicrobiales, and Synechococcus, coupled to an enrichment of total microbial metabolic pathways including phosphorus and nitrogen metabolism, sulfate reduction, virulence, and the degradation of hydrocarbons. Additionally, community beta-diversity was partitioned between the two sampling periods. This potentially reflected the influence of shifting allochtonous nutrient inputs on microbial communities and highlighted the temporally dynamic nature of the system. Combined, our results provide insights into the simultaneous influence of natural and anthropogenic drivers on the structure and function of microbial communities within a highly urbanized aquatic ecosystem
Determinants of gross motor function of young children with cerebral palsy: A prospective cohort study
Aim: The aim of this study was to test a model of determinants of gross motor function of young children with cerebral palsy (CP). Method: Four hundred and twenty-nine children with CP (242 males, 187 females; mean age 3y 2mo, SD 11mo) representing all levels of the Gross Motor Function Classification System (GMFCS) participated. Children in levels I to II and III to V were classified as Groups 1 and 2 respectively. Distribution of CP was quadriplegia, 44%; hemiplegia, 24%; diplegia, 23%; triplegia, 6%; and monoplegia, 2% (data not available for 1%). Impairment and motor function data were collected by reliable assessors; parents completed questionnaires on health conditions and adaptive behavior. Seven months later, parents were interviewed about family life and services received. One year after the study onset, motor function was re-evaluated. Analysis involved structural equation modeling. Results: The well-fitting model explained 58% and 75% of the variance in motor function at study completion for Groups 1 and 2 respectively. Primary impairments (spasticity, quality of movement, postural stability, and distribution of involvement; β=0.52-0.68) and secondary impairments (strength, range of motion limitations, and reduced endurance; β=0.25-0.26) explained the most variance. Adaptive behavior was a significant determinant only for Group 2 (β=0.21) and participation in community programs was significant only in Group 1 (β=0.13). Interpretation: Motor function is supported by optimizing body structures and function for all children and enhancing adaptive behavior for children with greater motor challenges. © 2013 Mac Keith Press
An Anomalous Extinction Law in the Cep OB3b Young Cluster: Evidence for dust processing during gas dispersal
We determine the extinction law through Cep OB3b, a young cluster of 3000
stars undergoing gas dispersal. The extinction is measured toward 76 background
K giants identified with MMT/Hectospec spectra. Color excess ratios were
determined toward each of the giants using and photometry from the
literature, ,, and photometry from SDSS and , , and
photometry from 2MASS. These color excess ratios were the used to construct the
extinction law through the dusty material associated with Cep OB3b. The
extinction law through Cep OB3b is intermediate between the and
laws commonly used for the diffuse atomic ISM and dense molecular
clouds, respectively. The dependence of the extinction law on line-of-sight
is investigated and we find the extinction law becomes shallower for
regions with magnitudes. We speculate that the intermediate dust
law results from dust processing during the dispersal of the molecular cloud by
the cluster.Comment: 31 pages, 10 Figures, 3 Tables, accepted for publication in Ap
Spitzer Imaging of the Nearby Rich Young Cluster, Cep OB3b
We map the full extent of a rich massive young cluster in the Cep OB3b
association with the IRAC and MIPS instruments aboard the {\it Spitzer} Space
Telescope and the ACIS instrument aboard the X-Ray Observatory.
At 700 pc, it is revealed to be the second nearest large ( member),
young ( Myr) cluster known. In contrast to the nearest large cluster, the
Orion Nebula Cluster, Cep OB3b is only lightly obscured and is mostly located
in a large cavity carved out of the surrounding molecular cloud. Our infrared
and X-ray datasets, as well as visible photometry from the literature, are used
to take a census of the young stars in Cep OB3b. We find that the young stars
within the cluster are concentrated in two sub-clusters; an eastern
sub-cluster, near the Cep B molecular clump, and a western sub-cluster, near
the Cep F molecular clump. Using our census of young stars, we examine the
fraction of young stars with infrared excesses indicative of circumstellar
disks. We create a map of the disk fraction throughout the cluster and find
that it is spatially variable. Due to these spatial variations, the two
sub-clusters exhibit substantially different average disk fractions from each
other: and . We discuss whether the discrepant disk
fractions are due to the photodestruction of disks by the high mass members of
the cluster or whether they result from differences in the ages of the
sub-clusters. We conclude that the discrepant disk fractions are most likely
due to differences in the ages.Comment: 48 Pages, 12 figures, 6 table
DNA methylation at a nutritionally sensitive region of the PAX8 gene is associated with thyroid volume and function in Gambian children.
Funder: Wellcome TrustPAX8 is a key thyroid transcription factor implicated in thyroid gland differentiation and function, and PAX8 gene methylation is reported to be sensitive to the periconceptional environment. Using a novel recall-by-epigenotype study in Gambian children, we found that PAX8 hypomethylation at age 2 years is associated with a 21% increase in thyroid volume and an increase in free thyroxine (T4) at 5 to 8 years, the latter equivalent to 8.4% of the normal range. Free T4 was associated with a decrease in DXA-derived body fat and bone mineral density. Furthermore, offspring PAX8 methylation was associated with periconceptional maternal nutrition, and methylation variability was influenced by genotype, suggesting that sensitivity to environmental exposures may be under partial genetic control. Together, our results demonstrate a possible link between early environment, PAX8 gene methylation and thyroid gland development and function, with potential implications for early embryonic programming of thyroid-related health and disease
Hard X-ray Emission Associated with White Dwarfs
We have used the WGACAT to search for hard X-ray sources associated with
white dwarfs (WDs) from the catalog of McCook & Sion (1999). We find 17 X-ray
sources coincident with WDs showing significant hard X-ray emission at energies
>0.5 keV. Twelve of these WDs are in known binary systems, in two of which the
accretion of the close companion's material onto the white dwarf produces the
hard X-ray emission, and in the other ten of which the late-type companions'
coronal activity emits hard X-rays. One WD is projected near an AGN which is
responsible for the hard X-ray emission. The remaining four WDs and two
additional white dwarfs with hard X-ray emission appear single. The lack of
near-IR excess from the apparently single WDs suggests that either X-ray
observations are more effective than near-IR photometry in diagnosing faint
companions or a different emission mechanism is needed. It is intriguing that
50% of the six apparently single WDs with hard X-ray emission are among the
hottest WDs. We have compared X-ray properties of 11 hot WDs with different
spectral types, and conclude that stellar pulsation and fast stellar winds are
not likely the origin of the hard X-ray emission, but a leakage of the
high-energy Wien tail of emission from deep in the stellar atmosphere remains a
tantalizing source of hard X-ray emission from hot DO and DQZO WDs. (This
abstract is an abridged version.)Comment: 35 pages, 8 figures, 4 tables, accepted for publication in AJ, April
issu
Technoscience and the modernization of freshwater fisheries assessment and management
Inland fisheries assessment and management are challenging given the inherent com-
plexity of working in diverse habitats (e.g., rivers, lakes, wetlands) that are dynamic
on organisms that are often cryptic and where fishers are often highly mobile. Yet,
technoscience is offering new tools that have the potential to reimagine how inland
fisheries are assessed and managed. So-called ‘‘technoscience’’ refers to instances in
which science and technology unfurl together, offering novel ways of spurring and
achieving meaningful change. This paper considers the role of technoscience and its
potential for modernizing the assessment and management of inland fisheries. It first
explores technoscience and its potential benefits, followed by presentation of a series
of synopses that explore the application (both successes and challenges) of new tech-
nologies such as environmental DNA (eDNA), genomics, electronic tags, drones, phone
apps, iEcology, and artificial intelligence to assessment and management. The paper
also considers the challenges and barriers that exist in adopting new technologies. The
paper concludes with a provocative assessment of the potential of technoscience to
reform and modernize inland fisheries assessment and management. Although these
tools are increasingly being embraced, there is a lack of platforms for aggregating these
data streams and providing managers with actionable information in a timely manner.
The ideas presented here should serve as a catalyst for beginning to work collectively
and collaboratively towards fisheries assessment and management systems that harness
the power of technology and serve to modernize inland fisheries management. Such
transformation is urgently needed given the dynamic nature of environmental change,
the evolving threat matrix facing inland waters, and the complex behavior of fishers.
Quite simply, a dynamic world demands dynamic fisheries management; technoscience
has made that within reach.publishedVersio
Testing the universality of star formation - I. Multiplicity in nearby star-forming regions
We have collated multiplicity data for five clusters (Taurus, Chamaeleon I,
Ophiuchus, IC348, and the Orion Nebula Cluster). We have applied the same mass
ratio (flux ratios of delta K <= 2.5) and primary mass cuts (~0.1-3.0 Msun) to
each cluster and therefore have directly comparable binary statistics for all
five clusters in the separation range 62-620 au, and for Taurus, Chamaeleon I,
and Ophiuchus in the range 18-830 au. We find that the trend of decreasing
binary fraction with cluster density is solely due to the high binary fraction
of Taurus, the other clusters show no obvious trend over a factor of nearly 20
in density.
With N-body simulations we attempt to find a set of initial conditions that
are able to reproduce the density, morphology and binary fractions of all five
clusters. Only an initially clumpy (fractal) distribution with an initial total
binary fraction of 73 per cent (17 per cent in the range 62-620 au) is able to
reproduce all of the observations (albeit not very satisfactorily). Therefore,
if star formation is universal the initial conditions must be clumpy and with a
high (but not 100 per cent) binary fraction. This could suggest that most
stars, including M-dwarfs, form in binaries.Comment: Accepted for publication in MNRAS, 19 pages, 22 figure
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