269 research outputs found
Designing Mobile Applications Around Load-Balancing Principles to Improve Performance.
Developers of mobile applications commonly delegate computations to networked resources, which have considerably more processing capacity than contemporary mobile devices. The work described here investigates an alternative approach to managing these computations, which uses a dynamic load-balancing algorithm to divide processing work between a mobile device and a back-end server
Building social license to operate through community engagement: the WUSC-Rio Tinto Alcan partnership in Ghana
Presenting the case study of the WUSC-Rio Tinto Alcan partnership in Ghana, this article focuses on the benefits and challenges of a multi-stakeholder partnership between an NGO, a mining company, governments and local communities. Strong community empowerment, alignment of multiple stakeholders’ interests, and the contribution of an expert development NGO definitely contributed to the success of the project, while also strengthening Rio Tinto’s social license to operate
Computational and experimental investigation of the flow structure and vortex dynamics in the wake of a Formula 1 tire
The flowfield around a 60% scale stationary Formula 1 tire in contact with the ground in a closed wind tunnel was examined experimentally in order to assess the accuracy of different turbulence modeling techniques. The results of steady RANS and Large Eddy Simulation (LES) were compared with PIV data, which was obtained within the same project. The far wake structure behind the wheel was dominated by two strong counter-rotating vortices. The locations of the vortex cores, extracted from the LES and PIV data as well as computed using different RANS models, showed that the LES predictions are closest to the PIV vortex cores. All turbulence models were able to accurately predict the region of strong downward velocity between the vortex cores in the center-plane of the tire, but discrepancies arose when velocity profiles were compared close to the inboard and outboard edges of the tire. These discrepancies could be due to the sensitivity of the CFD solution to the tire shoulder profile, which may not exactly match the experimental profile. In the near wake region directly behind the contact patch of the tire, contour plots of in-plane velocity were compared for all three datasets. The LES simulation again matched well with the PIV data
Comparative genomic analysis of the family Iridoviridae: re-annotating and defining the core set of iridovirus genes
BACKGROUND: Members of the family Iridoviridae can cause severe diseases resulting in significant economic and environmental losses. Very little is known about how iridoviruses cause disease in their host. In the present study, we describe the re-analysis of the Iridoviridae family of complex DNA viruses using a variety of comparative genomic tools to yield a greater consensus among the annotated sequences of its members. RESULTS: A series of genomic sequence comparisons were made among, and between the Ranavirus and Megalocytivirus genera in order to identify novel conserved ORFs. Of these two genera, the Megalocytivirus genomes required the greatest number of altered annotations. Prior to our re-analysis, the Megalocytivirus species orange-spotted grouper iridovirus and rock bream iridovirus shared 99% sequence identity, but only 82 out of 118 potential ORFs were annotated; in contrast, we predict that these species share an identical complement of genes. These annotation changes allowed the redefinition of the group of core genes shared by all iridoviruses. Seven new core genes were identified, bringing the total number to 26. CONCLUSION: Our re-analysis of genomes within the Iridoviridae family provides a unifying framework to understand the biology of these viruses. Further re-defining the core set of iridovirus genes will continue to lead us to a better understanding of the phylogenetic relationships between individual iridoviruses as well as giving us a much deeper understanding of iridovirus replication. In addition, this analysis will provide a better framework for characterizing and annotating currently unclassified iridoviruses
Implications of leg length for metabolic health and fitness
BACKGROUND AND OBJECTIVES: Several studies have linked longer legs with favorable adult metabolic health outcomes and greater offspring birth weight. A recent Mendelian randomization study suggested a causal link between height and cardiometabolic risk; however, the underlying reasons remain poorly understood. METHODOLOGY: Using a cross-sectional design, we tested in a convenience sample of 70 healthy young women whether birth weight and tibia length as markers of early-life conditions associated more strongly with metabolically beneficial traits like organ size and skeletal muscle mass (SMM) than a statistically derived height-residual variable indexing later, more canalized growth. RESULTS: Consistent with the ‘developmental origins of health and disease’ hypothesis, we found relatively strong associations of tibia length—but not birth weight—with adult organ size, brain size, SMM and resting energy expenditure measured by magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry and indirect calorimetry, respectively. CONCLUSIONS AND IMPLICATIONS: Building on prior work, these results suggest that leg length is a sensitive marker of traits directly impacting metabolic and reproductive health. Alongside findings in the same sample relating tibia length and height-residual to MRI-measured pelvic dimensions, we suggest there may exist a degree of coordination in the development of long bone, lean mass and pelvic traits, possibly centered on early, pre-pubertal growth periods. Such phenotypic coordination has important implications for fitness, serving to benefit both adult health and the health of offspring in subsequent generations
Developing a Web Site to Provide Geologic Data and Map Products for Allen County, Indiana
This poster was presented at the 2007 meeting of the Digital Mapping Techniques Conference in Columbia, South Carolina, May 20-23, 2007.The Internet is becoming the medium of choice for delivering geologic information to both technical users and the general public. The Indiana Geological Survey (IGS) is currently creating a Web-based glacial and bedrock geologic map site for Allen County in northeastern Indiana. Allen County is the site of Fort Wayne, Indiana’s second largest city, and lies within IGS mapping and outreach priority areas based on population density and transportation corridors. This Web site provides detailed geologic information in an area that continues to experience pressure on natural resources by a large population and expanding transportation network. It is anticipated that the information from the Web site will be widely used by the general public and by industry and government entities.
The Allen County Web site includes an Internet map server (IMS), as well as
illustrations, educational summaries, and discussions of geologic maps, terrain
images, and databases that complement the IMS. The site provides a front-end to the IGS enterprise geodatabases, which contain information used simultaneously for research and for viewing by the general public. The geodatabase systems allow maps and data to be efficiently created, managed, updated, and distributed.
Maps provided on the Allen County Web site include: (1) digital elevation model
terrain, (2) Landsat imagery, (3) surficial geology, (4) drift thickness, (5) bedrock
topography, (6) bedrock geology, and (7) water-table elevation. Technical database information includes: (1) lithologic information compiled from water-well information in the Indiana Department of Natural Resources, Division of Water well records,
(2) natural gamma-ray geophysical log data, (3) stratigraphic test hole data, and
(4) petroleum-well data. The development of the Web site was funded by the IGS and the Central Great Lakes Geologic Mapping Coalition.U.S. Geological Surve
The relationship between mental health conditions and hearing loss in low- and middle-income countries.
OBJECTIVE: Hearing loss can have far-reaching effects on social, emotional and cognitive development, but few studies have addressed the link with mental health conditions. We conducted a systematic review of the association between hearing loss and mental health conditions in low- and middle-income countries (LMICs). METHODS: We searched six electronic databases using predetermined criteria to retrieve original research reporting mental health in people with hearing loss. We considered quantitative studies measuring any type of mental health conditions according to the ICD10 classifications of 'Mental and behavioural disorders' in relation to any measure of hearing loss. We assessed risk of bias using a set of criteria according to the SIGN50 guidelines. RESULTS: We included 12 studies evaluating 35Â 604 people with hearing loss in 10 countries. Poorer mental health (measured as stress and anxiety, depression, and/or behavioural and emotional disorders) was more common among people with hearing loss compared to those without in 10 studies. One study found no difference in mental health outcomes between people with hearing, visual and no impairment. Another study reported that after hearing aids, those with severe hearing loss had significant improvement in psychosocial function, compared to no change among those without hearing loss. Overall, one study was judged to be high quality, seven medium quality and four low quality. CONCLUSIONS: Included studies showed a trend towards poorer mental health outcomes for people with hearing loss than for those without. However, our findings indicate that very few high-quality studies have been conducted in LMICs
Numerical Continuation of Limit Cycle Oscillations and Bifurcations in High-Aspect-Ratio Wings
This paper applies numerical continuation techniques to a nonlinear aeroelastic model of a highly flexible, high-aspect-ratio wing. Using continuation, it is shown that subcritical limit cycle oscillations, which are highly undesirable phenomena previously observed in numerical and experimental studies, can exist due to geometric nonlinearity alone, without need for nonlinear or even unsteady aerodynamics. A fully nonlinear, reduced-order beam model is combined with strip theory and one-parameter continuation is used to directly obtain equilibria and periodic solutions for varying airspeeds. The two-parameter continuation of specific bifurcations (i.e., Hopf points and periodic folds) reveals the sensitivity of these complex dynamics to variations in out-of-plane, in-plane and torsional stiffness and a ‘wash out’ stiffness coupling parameter. Overall, this paper demonstrates the applicability of continuation to nonlinear aeroelastic analysis and shows that complex dynamical phenomena, which cannot be obtained by linear methods or numerical integration, readily exist in this type of system due to geometric nonlinearity
Existence, functional impairment, and lung repair potential of endothelial colony-forming cells in oxygen-induced arrested alveolar growth
BACKGROUND: Bronchopulmonary dysplasia and emphysema are life-threatening diseases resulting from impaired alveolar development or alveolar destruction. Both conditions lack effective therapies. Angiogenic growth factors promote alveolar growth and contribute to alveolar maintenance. Endothelial colony-forming cells (ECFCs) represent a subset of circulating and resident endothelial cells capable of self-renewal and de novo vessel formation. We hypothesized that resident ECFCs exist in the developing lung, that they are impaired during arrested alveolar growth in experimental bronchopulmonary dysplasia, and that exogenous ECFCs restore disrupted alveolar growth.
METHODS AND RESULTS: Human fetal and neonatal rat lungs contain ECFCs with robust proliferative potential, secondary colony formation on replating, and de novo blood vessel formation in vivo when transplanted into immunodeficient mice. In contrast, human fetal lung ECFCs exposed to hyperoxia in vitro and neonatal rat ECFCs isolated from hyperoxic alveolar growth-arrested rat lungs mimicking bronchopulmonary dysplasia proliferated less, showed decreased clonogenic capacity, and formed fewer capillary-like networks. Intrajugular administration of human cord blood-derived ECFCs after established arrested alveolar growth restored lung function, alveolar and lung vascular growth, and attenuated pulmonary hypertension. Lung ECFC colony- and capillary-like network-forming capabilities were also restored. Low ECFC engraftment and the protective effect of cell-free ECFC-derived conditioned media suggest a paracrine effect. Long-term (10 months) assessment of ECFC therapy showed no adverse effects with persistent improvement in lung structure, exercise capacity, and pulmonary hypertension.
CONCLUSIONS: Impaired ECFC function may contribute to arrested alveolar growth. Cord blood-derived ECFC therapy may offer new therapeutic options for lung diseases characterized by alveolar damage
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