1,028 research outputs found

    Forensic Investigation of Failed Mast Arms of Traffic Signal Supported Structures

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    In Missouri, 11 traffic signal mast arms fractured at the arm-post weld connection in 7 years. To reduce this fatigue failure, the Missouri Department of Transportation developed a fatigue-resistant weld profile that increases the weld leg and reduces the slope of the weld at the toe. This study investigated causes of the failed arms, compared performance of new and old weld profiles, and suggested retrofitting measures for further investigation. The scope included a metallurgical investigation of one failed field mast arm, laboratory fatigue testing of five prototype mast arms (two new and three old profiles), and laboratory failure analysis of one arm tested to cracking. Metallographic and fractographic analyses indicated that the fatigue crack in the failed mast arm initiates near the weld toe of the arm due to undercutting, creating a sharp local toe angle. Location of undercutting at the heat-affected zone of the base material, where the material is softest, further contributed to early fatigue failure. Tests showed that the new weld profile does not consistently increase fatigue strength. Premature fracture surfaces of one tested arm indicated that the fatigue cracks initiate in an area at the weld toe as observed in the failed mast arm. Therefore, changing the weld profile alone is unlikely to increase mast arm fatigue life. Pinning the weldment surface at the weld toe of mast arms is suggested to increase the life of mast arms

    Dengue and climate change in Australia: predictions for the future should incorporate knowledge from the past

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    •Dengue transmission in Australia is currently restricted to Queensland, where the vector mosquito Aedes aegypti is established. Locally acquired infections have been reported only from urban areas in the north-east of the state, where the vector is most abundant. •Considerable attention has been drawn to the potential impact of climate change on dengue distribution within Australia, with projections for substantial rises in incidence and distribution associated with increasing temperatures. •However, historical data show that much of Australia has previously sustained both the vector mosquito and dengue viruses. Although current vector distribution is restricted to Queensland, the area inhabited by A. aegypti is larger than the disease-transmission areas, and is not restricted by temperature (or vector-control programs); thus, it is unlikely that rising temperatures alone will bring increased vector or virus distribution. •Factors likely to be important to dengue and vector distribution in the future include increased dengue activity in Asian and Pacific nations that would raise rates of virus importation by travellers, importation of vectors via international ports to regions without A. aegypti, higher rates of domestic collection and storage of water that would provide habitat in urban areas, and growing human populations in northern Australia. •Past and recent successful control initiatives in Australia lend support to the idea that well resourced and functioning surveillance programs, and effective public health intervention capabilities, are essential to counter threats from dengue and other mosquito-borne diseases. •Models projecting future activity of dengue (or other vector-borne disease) with climate change should carefully consider the local historical and contemporary data on the ecology and distribution of the vector and local virus transmission

    Digitizing localism: anticipating, assembling and animating a ‘space’ for UK hyperlocal media production

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    This paper presents an unconventional view of media production, not as the direct production of media content or forms, but the cultivation of spaces for media production taking place elsewhere. I draw on a close analysis of Destination Local, a program of UK charity Nesta, which focused on the implications of location-based technologies for the emergent field of ‘hyperlocal’ media. Although the first round of the program – the focus in this paper – funded 10 experimental projects alongside extensive research, my argument is that Destination Local was less a matter of enabling specific place-based hyperlocal media outlets. Rather, it was an attempt to anticipate, assemble and animate a broader UK hyperlocal media ‘space’, composed of both technical ecologies (e.g. data, devices, platforms, standards) and practical fields (e.g. journalism, software development, local government, community activism). This space, I argue, was anchored to a largely implicit political discourse of localism

    Hierarchical Hough all-sky search for periodic gravitational waves in LIGO S5 data

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    We describe a new pipeline used to analyze the data from the fifth science run (S5) of the LIGO detectors to search for continuous gravitational waves from isolated spinning neutron stars. The method employed is based on the Hough transform, which is a semi-coherent, computationally efficient, and robust pattern recognition technique. The Hough transform is used to find signals in the time-frequency plane of the data whose frequency evolution fits the pattern produced by the Doppler shift imposed on the signal by the Earth's motion and the pulsar's spin-down during the observation period. The main differences with respect to previous Hough all-sky searches are described. These differences include the use of a two-step hierarchical Hough search, analysis of coincidences among the candidates produced in the first and second year of S5, and veto strategies based on a χ2\chi^2 test.Comment: 7 pages, 2 figures, Amaldi08 proceedings, submitted to JPC

    Murray Valley encephalitis virus surveillance and control initiatives in Australia.

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    Mechanisms for monitoring Murray Valley encephalitis (MVE) virus activity include surveillance of human cases, surveillance for activity in sentinel animals, monitoring of mosquito vectors and monitoring of weather conditions. The monitoring of human cases is only one possible trigger for public health action and the additional surveillance systems are used in concert to signal the risk of human disease, often before the appearance of human cases. Mosquito vector surveillance includes mosquito trapping for speciation and enumeration of mosquitoes to monitor population sizes and relative composition. Virus isolation from mosquitoes can also be undertaken. Monitoring of weather conditions and vector surveillance determines whether there is a potential for MVE activity to occur. Virus isolation from trapped mosquitoes is necessary to define whether MVE is actually present, but is difficult to deliver in a timely fashion in some jurisdictions. Monitoring of sentinel animals indicates whether MVE transmission to vertebrates is actually occurring. Meteorological surveillance can assist in the prediction of potential MVE virus activity by signalling conditions that have been associated with outbreaks of Murray Valley encephalitis in humans in the past. Predictive models of MVE virus activity for south-eastern Australia have been developed, but due to the infrequency of outbreaks, are yet to be demonstrated as useful for the forecasting of major outbreaks. Surveillance mechanisms vary across the jurisdictions. Surveillance of human disease occurs in all States and Territories by reporting of cases to health authorities. Sentinel flocks of chickens are maintained in 4 jurisdictions (Western Australia, the Northern Territory, Victoria and New South Wales) with collaborations between Western Australia and the Northern Territory. Mosquito monitoring complements the surveillance of sentinel animals in these jurisdictions. In addition, other mosquito monitoring programs exist in other States (including South Australia and Queensland). Public health control measures may include advice to the general public and mosquito management programs to reduce the numbers of both mosquito larvae and adult vectors. Strategic plans for public health action in the event of MVE virus activity are currently developed or being developed in New South Wales, the Northern Territory, South Australia, Western Australia and Victoria. A southern tri-State agreement exists between health departments of New South Wales, Victoria and South Australia and the Commonwealth Department of Health and Aged Care. All partners have agreed to co-operate and provide assistance in predicting and combatting outbreaks of mosquito-borne disease in south-eastern Australia. The newly formed National Arbovirus Advisory Committee is a working party providing advice to the Communicable Diseases Network Australia on arbovirus surveillance and control. Recommendations for further enhancement of national surveillance for Murray Valley encephalitis are described

    Disentangling a group of lensed submm galaxies at z∼ 2.9

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    MS0451.6−0305 is a rich galaxy cluster whose strong lensing is particularly prominent at submm wavelengths. We combine new Submillimetre Common-User Bolometer Array (SCUBA)-2 data with imaging from Herschel Spectral and Photometric Imaging Receiver (SPIRE) and PACS and Hubble Space Telescope in order to try to understand the nature of the sources being lensed. In the region of the ‘giant submm arc', we uncover seven multiply imaged galaxies (up from the previously known four), of which six are found to be at a redshift of z∼2.9, and possibly constitute an interacting system. Using a novel forward-modelling approach, we are able to simultaneously deblend and fit spectral energy distributions to the individual galaxies that contribute to the giant submm arc, constraining their dust temperatures, far-infrared luminosities, and star formation rates (SFRs). The submm arc first identified by SCUBA can now be seen to be composed of at least five distinct sources, four of these within a galaxy group at z∼2.9. Only a handful of lensed galaxy groups at this redshift are expected on the sky, and thus this is a unique opportunity for studying such systems in detail. The total unlensed luminosity for this galaxy group is (3.1±0.3)×1012 L⊙, which gives an unlensed SFR of (450±50) M⊙yr−1. This finding suggests that submm source multiplicity, due to physically associated groupings as opposed to chance alignment, extends to fainter flux densities than previously discovered. Many of these systems may also host optical companions undetected in the submm, as is the case her

    Common Polymorphisms at the <i>CYP17A1 </i>Locus Associate With Steroid Phenotype:Support for Blood Pressure Genome-Wide Association Study Signals at This Locus

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    Genome-wide association studies implicate the CYP17A1 gene in human blood pressure regulation although the causative polymorphisms are as yet unknown. We sought to identify common polymorphisms likely to explain this association. We sequenced the CYP17A1 locus in 60 normotensive individuals and observed 24 previously identified single-nucleotide polymorphisms with minor allele frequency &gt;0.05. From these, we selected, for further studies, 7 polymorphisms located ≤2 kb upstream of the CYP17A1 transcription start site. In vitro reporter gene assays identified 3 of these (rs138009835, rs2150927, and rs2486758) as having significant functional effects. We then analyzed the association between the 7 polymorphisms and the urinary steroid metabolites in a hypertensive cohort (n=232). Significant associations included that of rs138009835 with aldosterone metabolite excretion; rs2150927 associated with the ratio of tetrahydrodeoxycorticosterone to tetrahydrodeoxycortisol, which we used as an index of 17α-hydroxylation. Linkage analysis showed rs138009835 to be the only 1 of the 7 polymorphisms in strong linkage disequilibrium with the blood pressure–associated polymorphisms identified in the previous studies. In conclusion, we have identified, characterized, and investigated common polymorphisms at the CYP17A1 locus that have functional effects on gene transcription in vitro and associate with corticosteroid phenotype in vivo. Of these, rs138009835—which we associate with changes in aldosterone level—is in strong linkage disequilibrium with polymorphisms linked by genome-wide association studies to blood pressure regulation. This finding clearly has implications for the development of high blood pressure in a large proportion of the population and justifies further investigation of rs138009835 and its effects
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