142 research outputs found
The Automated Delimitation of Maritime Boundaries - An Australian Perspective
Determining the accurate location of maritime boundaries and computing the outer limits of the extended continental shelf can be a mathematically demanding and computationally intensive task. This paper considers the relevant issues, particularly from an Australian perspective. An efficient and automated solution to maritime boundary and extended continental shelf delimitation has been designed and implemented in the form of a software package known as MarZone. This paper introduces the MarZone software. In the design of MarZone, emphasis was placed on a geodetically rigorous methodology while at the same time maintaining strict agreement with the relevant provisions of the United Nations Convention on the Law of the Sea. The reasons for such an emphasis are explained in the paper
Biophysical assessment of reefs in Keppel Bay: a baseline study (April 2007)
The Keppel Islands are a group of 16 continental islands lying 18 km off the coastal town of Yeppoon in the southern Great Barrier Reef. Located in the shallow basin to the north of Keppel Bay, the islands are host to a patchwork of fringing reefs in various forms of development. Coral communities are abundant in some locations, and coral cover is high (60 to 70%) relative to the average at sites surveyed by the Australian Institute of Marine Scienceâs Long-Term Monitoring Program (~35%), and are often dominated by extensive stands of branching Acropora that extend into shallow water. These âstaghornâ corals are vulnerable to impacts caused by environmental stresses such as elevated sea temperature (causing coral bleaching events), degraded water quality (associated with hyposaline floods events) and physical damage (from cyclones, storms and anchoring). The Fitzroy River, one of the largest catchments in Queensland, is about 40 km to the south of the Keppel Islands. Large flood plumes occur approximately every 10 years, and the soft riverine sediments are regularly re-suspended in the shallow bay by wind and tide action causing high turbidity. Heavy rainfall also affects the shallow reef flat habitats, with reported incidences of coral mortality caused by heavy rain at times of extreme low tidesID: 176
129Xe and free-breathing 1H ventilation MRI in patients with cystic fibrosis: a dual-center study
Background
Free-breathing 1H ventilation MRI shows promise but only single-center validation has yet been performed against methods which directly image lung ventilation in patients with cystic fibrosis (CF).
Purpose
To investigate the relationship between 129Xe and 1H ventilation images using data acquired at two centers.
Study type
Sequence comparison.
Population
Center 1; 24 patients with CF (12 female) aged 9â47âyears. Center 2; 7 patients with CF (6 female) aged 13â18âyears, and 6 healthy controls (6 female) aged 21â31âyears. Data were acquired in different patients at each center.
Field Strength/Sequence
1.5 T, 3D steady-state free precession and 2D spoiled gradient echo.
Assessment
Subjects were scanned with 129Xe ventilation and 1H free-breathing MRI and performed pulmonary function tests. Ventilation defect percent (VDP) was calculated using linear binning and images were visually assessed by H.M., L.J.S., and G.J.C. (10, 5, and 8âyears' experience).
Statistical Tests
Correlations and linear regression analyses were performed between 129Xe VDP, 1H VDP, FEV1, and LCI. BlandâAltman analysis of 129Xe VDP and 1H VDP was carried out. Differences in metrics were assessed using one-way ANOVA or KruskalâWallis tests.
Results
129Xe VDP and 1H VDP correlated strongly with; each other (r = 0.84), FEV1 z-score (129Xe VDP r = â0.83, 1H VDP r = â0.80), and LCI (129Xe VDP r = 0.91, 1H VDP r = 0.82). BlandâAltman analysis of 129Xe VDP and 1H VDP from both centers had a bias of 0.07% and limits of agreement of â16.1% and 16.2%. Linear regression relationships of VDP with FEV1 were not significantly different between 129Xe and 1H VDP (P = 0.08), while 129Xe VDP had a stronger relationship with LCI than 1H VDP.
Data Conclusion
1H ventilation MRI shows large-scale agreement with 129Xe ventilation MRI in CF patients with established lung disease but may be less sensitive to subtle ventilation changes in patients with early-stage lung disease.
Evidence Level
2
Technical Efficacy
Stage
E-retailing ethics in Egypt and its effect on customer repurchase intention
The theoretical understanding of online shopping behaviour has received much attention. Less focus has been given to the formation of the ethical issues that result from online shopper interactions with e-retailers. The vast majority of earlier research on this area is conceptual in nature and limited in scope by focusing on consumersâ privacy issues. Therefore, the purpose of this paper is to propose a theoretical model explaining what factors contribute to online retailing ethics and its effect on customer repurchase intention. The data were analysed using variance-based structural equation modelling, employing partial least squares regression. Findings indicate that the five factors of the online retailing ethics (security, privacy, non- deception, fulfilment/reliability, and corporate social responsibility) are strongly predictive of online consumersâ repurchase intention. The results offer important implications for e-retailers and are likely to stimulate further research in the area of e-ethics from the consumersâ perspective
Isogeometric analysis: an overview and computer implementation aspects
Isogeometric analysis (IGA) represents a recently developed technology in
computational mechanics that offers the possibility of integrating methods for
analysis and Computer Aided Design (CAD) into a single, unified process. The
implications to practical engineering design scenarios are profound, since the
time taken from design to analysis is greatly reduced, leading to dramatic
gains in efficiency. The tight coupling of CAD and analysis within IGA requires
knowledge from both fields and it is one of the goals of the present paper to
outline much of the commonly used notation. In this manuscript, through a clear
and simple Matlab implementation, we present an introduction to IGA applied to
the Finite Element (FE) method and related computer implementation aspects.
Furthermore, implemen- tation of the extended IGA which incorporates enrichment
functions through the partition of unity method (PUM) is also presented, where
several examples for both two-dimensional and three-dimensional fracture are
illustrated. The open source Matlab code which accompanies the present paper
can be applied to one, two and three-dimensional problems for linear
elasticity, linear elastic fracture mechanics, structural mechanics
(beams/plates/shells including large displacements and rotations) and Poisson
problems with or without enrichment. The Bezier extraction concept that allows
FE analysis to be performed efficiently on T-spline geometries is also
incorporated. The article includes a summary of recent trends and developments
within the field of IGA
The Scientific Foundations of Forecasting Magnetospheric Space Weather
The magnetosphere is the lens through which solar space weather phenomena are focused and directed towards the Earth. In particular, the non-linear interaction of the solar wind with the Earth's magnetic field leads to the formation of highly inhomogenous electrical currents in the ionosphere which can ultimately result in damage to and problems with the operation of power distribution networks. Since electric power is the fundamental cornerstone of modern life, the interruption of power is the primary pathway by which space weather has impact on human activity and technology. Consequently, in the context of space weather, it is the ability to predict geomagnetic activity that is of key importance. This is usually stated in terms of geomagnetic storms, but we argue that in fact it is the substorm phenomenon which contains the crucial physics, and therefore prediction of substorm occurrence, severity and duration, either within the context of a longer-lasting geomagnetic storm, but potentially also as an isolated event, is of critical importance. Here we review the physics of the magnetosphere in the frame of space weather forecasting, focusing on recent results, current understanding, and an assessment of probable future developments.Peer reviewe
Genome-Wide Association Study in BRCA1 Mutation Carriers Identifies Novel Loci Associated with Breast and Ovarian Cancer Risk
BRCA1-associated breast and ovarian cancer risks can be modified by common genetic variants. To identify further cancer risk-modifying loci, we performed a multi-stage GWAS of 11,705 BRCA1 carriers (of whom 5,920 were diagnosed with breast and 1,839 were diagnosed with ovarian cancer), with a further replication in an additional sample of 2,646 BRCA1 carriers. We identified a novel breast cancer risk modifier locus at 1q32 for BRCA1 carriers (rs2290854, P = 2.7Ă10-8, HR = 1.14, 95% CI: 1.09-1.20). In addition, we identified two novel ovarian cancer risk modifier loci: 17q21.31 (rs17631303, P = 1.4Ă10-8, HR = 1.27, 95% CI: 1.17-1.38) and 4q32.3 (rs4691139, P = 3.4Ă10-8, HR = 1.20, 95% CI: 1.17-1.38). The 4q32.3 locus was not associated with ovarian cancer risk in the general population or BRCA2 carriers, suggesting a BRCA1-specific associat
The Physical Processes of CME/ICME Evolution
As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind at Earth. Here, we strive to provide a fresh perspective on the post-eruption and interplanetary evolution of CMEs, focusing on the physical processes that define the many complex interactions of the ejected plasma with its surroundings as it departs the corona and propagates through the heliosphere. We summarize the ways CMEs and their interplanetary CMEs (ICMEs) are rotated, reconfigured, deformed, deflected, decelerated and disguised during their journey through the solar wind. This study then leads to consideration of how structures originating in coronal eruptions can be connected to their far removed interplanetary counterparts. Given that ICMEs are the drivers of most geomagnetic storms (and the sole driver of extreme storms), this work provides a guide to the processes that must be considered in making space weather forecasts from remote observations of the corona.Peer reviewe
Age at first birth in women is genetically associated with increased risk of schizophrenia
Prof. Paunio on PGC:n jÀsenPrevious studies have shown an increased risk for mental health problems in children born to both younger and older parents compared to children of average-aged parents. We previously used a novel design to reveal a latent mechanism of genetic association between schizophrenia and age at first birth in women (AFB). Here, we use independent data from the UK Biobank (N = 38,892) to replicate the finding of an association between predicted genetic risk of schizophrenia and AFB in women, and to estimate the genetic correlation between schizophrenia and AFB in women stratified into younger and older groups. We find evidence for an association between predicted genetic risk of schizophrenia and AFB in women (P-value = 1.12E-05), and we show genetic heterogeneity between younger and older AFB groups (P-value = 3.45E-03). The genetic correlation between schizophrenia and AFB in the younger AFB group is -0.16 (SE = 0.04) while that between schizophrenia and AFB in the older AFB group is 0.14 (SE = 0.08). Our results suggest that early, and perhaps also late, age at first birth in women is associated with increased genetic risk for schizophrenia in the UK Biobank sample. These findings contribute new insights into factors contributing to the complex bio-social risk architecture underpinning the association between parental age and offspring mental health.Peer reviewe
Education and selfâregulation of learning for gifted pupils: systemic design and development
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