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Wind and wave climate in the Arctic Ocean as observed by altimeters

Twenty years (1996-2015) of satellite observations were used to study the climatology and trends of oceanic winds and waves in the Arctic Ocean in the summer season (August-September). The Atlantic-side seas, exposed to the open ocean, host more energetic waves than those on the Pacific side. Trend analysis shows a clear spatial (regional) and temporal (interannual) variability in wave height and wind speed. Waves in the Chukchi Sea, Beaufort Sea (near the northern Alaska), and Laptev Sea have been increasing at a rate of 0.1-0.3 m decade-1, found to be statistically significant at the 90% level. The trend of waves in the Greenland and Barents Seas, on the contrary, is weak and not statistically significant. In the Barents and Kara Seas, winds and waves initially increased between 1996 and 2006 and later decreased. Large-scale atmospheric circulations such as the Arctic Oscillation and Arctic dipole anomaly have a clear impact on the variation of winds and waves in the Atlantic sector. Comparison between alti…

Author: Liu, Qingxiang, Babanin, Alexander V., Zieger, Stefan, Young, Ian R., Guan, Changlong
Publication year: 2016
Publication type: Journal article
Status: Live|Last updated:February 23, 2017 4:10 PM
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Calibration and validation of HY-2 altimeter wave height

Hai Yang-2 (HY-2) satellite altimeter measurements of significant wave height (Hs) are analyzed over the period from 1 October 2011 to 6 December 2014. They are calibrated and validated against in situ buoys and other concurrently operating altimeters: Jason-2, CryoSat-2, and Satellite with Argos and ALtiKa (SARAL). In general, the HY-2 altimeter measurements agree well with buoy measurements, with a bias of -0.22m and a root-mean-square error (RMSE) of 0.30 m. When the reduced major axis (RMA) regression procedure was applied to the entire period, the RMSE was reduced by 33% to 0.2 m. A further comparison with other satellite altimeters, however, revealed two additional features of HY-2 Hs estimates over this period. First, a noticeable mismatch is present between HY-2 and the other satellite altimeters for high seas (Hs > 6 m). Second, a jump increase in HY-2 Hs values was detected starting in April 2013, which was associated with the switch to backup status of the HY-2 sensors and the subsequent update of …

Author: Liu, Qingxiang, Babanin, Alexander V., Guan, Changlong, Zieger, Stefan, Sun, Jian, Jia, Yongjun
Publication year: 2016
Publication type: Journal article
Status: Live|Last updated:February 23, 2017 4:08 PM
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Association of ideal cardiovascular health with vascular brain injury and incident dementia

Background and Purpose - The American Heart Association developed the ideal cardiovascular health (CVH) index as a simple tool to promote CVH; yet, its association with brain atrophy and dementia remains unexamined. Methods - Our aim was to investigate the prospective association of ideal CVH with vascular brain injury, including the 10-year risks of incident stroke and dementia, as well as cognitive decline and brain atrophy on magnetic resonance imaging, measured for ≈7 years. We studied 2750 stroke- and dementia-free Framingham Heart Study Offspring cohort participants (mean age, 62±9 years; 45% men). Ideal CVH was quantified on a 7-point scale with 1 point awarded for each of the following: nonsmoking status, ideal body mass index, regular physical activity, healthy diet, as well as optimum blood pressure, cholesterol, and fasting blood glucose. Both recent (baseline) and remote (6.9 years earlier) ideal CVH scores were examined. Results—Recent ideal CVH was associated with stroke (hazard ratio, 0.80; 95%…

Author: Pase, Matthew P., Beiser, Alexa, Enserro, Danielle, Xanthakis, Vanessa, Aparicio, Hugo, Satizabal, Claudia L., Himali, Jayandra J., Kase, Carlos S., V...
Publication year: 2016
Publication type: Journal article
Status: Live|Last updated:February 23, 2017 3:52 PM
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Association of serum vitamin D with the risk of incident dementia and subclinical indices of brain aging: the Framingham Heart Study

Background: identifying nutrition- and lifestyle-based risk factors for cognitive impairment and dementia may aid future primary prevention efforts. Objective:We aimed to examine the association of serum vitamin D levels with incident all-cause dementia, clinically characterized Alzheimer’s disease (AD), MRI markers of brain aging, and neuropsychological function. Methods:Framingham Heart Study participants had baseline serum 25-hydroxyvitamin D (25(OH)D) concentrations measured between 1986 and 2001. Vitamin D status was considered both as a continuous variable and dichotomized as deficient (<10 ng/mL), or at the cohort-specific 20th and 80th percentiles. Vitamin D was related to the 9-year risk of incident dementia (n = 1663), multiple neuropsychological tests (n = 1291) and MRI markers of brain volume, white matter hyperintensities and silent cerebral infarcts (n = 1139). Results:In adjusted models, participants with vitamin D deficiency (n = 104, 8% of the cognitive sample) displayed poorer performance on…

Author: Karakis, Ioannis, Pase, Matthew P., Beiser, Alexa, Booth, Sarah L., Jacques, Paul F., Rogers, Gail, DeCarli, Charles, Vasan, Ramachandran S., Himali, ...
Publication year: 2016
Publication type: Journal article
Status: Live|Last updated:February 23, 2017 3:45 PM
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Mixing of discontinuously deforming media

Mixing of materials is fundamental to many natural phenomena and engineering applications. The presence of discontinuous deformations - such as shear banding or wall slip - creates new mechanisms for mixing and transport beyond those predicted by classical dynamical systems theory. Here, we show how a novel mixing mechanism combining stretching with cutting and shuffling yields exponential mixing rates, quantified by a positive Lyapunov exponent, an impossibility for systems with cutting and shuffling alone or bounded systems with stretching alone, and demonstrate it in a fluid flow. While dynamical systems theory provides a framework for understanding mixing in smoothly deforming media, a theory of discontinuous mixing is yet to be fully developed. New methods are needed to systematize, explain, and extrapolate measurements on systems with discontinuous deformations. Here, we investigate webs of Lagrangian discontinuities and show that they provide a template for the overall transport dynamics. Considering s…

Author: Smith, L. D., Rudman, M., Lester, D. R., Metcalfe, G.
Publication year: 2016
Publication type: Journal article
Status: Live|Last updated:February 23, 2017 2:38 PM
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Study of functional metallic nano/microstructures for photonics applications

The manipulation of light and moulding its flow at the nanoscale dimensions are some of the pioneering research fields of physics in the current century. Artificially designed miniature optical structures can serve as the key elements for controlling light in a desired manner, which is promising for the rapid development of photovoltaics and communications. Here, we demonstrate that novel metallic nano/microstructures can possess unique optical properties and can be realised via the state-of-the-art fabrication technologies. These functional metallic structures have potential applications in the swift progress of future photovoltaic devices and high speed telecommunications systems.

Author: Hossain, Md Muntasir
Publication year: 2012
Publication type: Thesis (PhD)
Status: Live|Last updated:February 23, 2017 2:27 PM
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Creative artefact: the taste of translation; and Exegesis: the inner outed

How is new knowledge produced? For Deleuze & Guattari, 'the new is an outside that exists within this world, and as such it must be constructed' (O’Sullivan & Zepke 2008, p.2). My work demonstrates that practice-led research offers a liberating framework toward such 'production of the new' (O’Sullivan & Zepke 2008, p.2), an opportunity for the intuitive and creative wellspring of heart-knowing to cross-fertilise with the intellectual and reflective reservoir of the mind. Beginning with direct experience of the collective unconscious (Jung 1995), the research question I addressed in this project was: How do I bring inner knowing out onto an external plane? The particularities of my process toward the following research outcomes - an Exegesis titled The Inner Outed and a Creative Artefact, The Taste of Translation - documents how creative practice unlocks intellectual understanding as much as reflective inquiry underpins and enables ongoing creativity. In this way, research and practice coalesce to form a seaml…

Author: Gambling, Anne
Publication year: 2012
Publication type: Thesis (PhD)
Status: Live|Last updated:February 23, 2017 2:27 PM
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Seismic performance of insitu and precast soft storey buildings

Lightly reinforced concrete columns and soft storey configurations are prevalent in many old buildings in regions of lower seismicity. This type of construction is believed to have a very low lateral load and drift capacity from a conventional design perspective. Furthermore, the application of design standards in low and moderate seismic regions such as Australia, results in most of the lightly reinforced structures being deemed unsafe in an earthquake. Therefore, an earthquake damage reconnaissance, experimental field test, and laboratory study of non-ductile columns was undertaken to examine the drift capacity and failure mechanism of such columns. Firstly, a field reconnaissance was conducted in China after the Wenchuan Earthquake in 2008, particularly in regions with similar design intensity MMI VI to VIII experienced in Australia. A comparison between the Wenchuan Earthquake and the characteristics of design earthquakes in Australia was made to provide insight for the development of future design standa…

Author: Wibowo, Ari
Publication year: 2012
Publication type: Thesis (PhD)
Status: Live|Last updated:February 23, 2017 2:27 PM
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The inheritance: a novel and exegesis

This exegesis considers narrative theory and practice and how they impact upon our memories which are at least partly what builds the concept of self, meaning and identity. The basis of what follows is taken from narrative theory with a psychological and philosophical influence. The investigation reviews how narratives construct personal meaning and identity, and shows that there will be always be an 'incommensurability' (Bruner 1986, 1990, 2004) between society and the individual. Narrative meaning and identity is discussed throughout the paper via the ideas of master and personal narratives and how these differ, interact and direct lives. There are conflicts between the various master narratives we all imbibe from culture and society. It is from these master narratives that each of us build our personal narratives, which build meaning and personal identity. Our narratives are known or unknown---often hidden from one’s own view---and may clash with master narratives and with our other personal narratives. Si…

Author: Todd, Edward
Publication year: 2012
Publication type: Thesis (PhD)
Status: Live|Last updated:February 23, 2017 2:26 PM
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Genetic variability and protein-protein interactions of puroindolines in relation to wheat grain texture and antimicrobial properties

The puroindoline genes, Pina-D1 and Pinb-D1, have been shown to be linked to grain hardness, an important trait in the end-use quality of wheat and hence in international usage and trade of wheat. Variations, in either or both genes, or lack of expression of either gene, result in a hard texture of common wheat, while the durum wheat that lacks both Pin genes is extremely hard. Depending on the type of mutation, a range of hardness observed. There has been a great interest to search for further genetic variations in these genes, firstly, to understand better the way these genes affect grain texture, and secondly, to introduce new variations into breeding programs in order to improve the end-use quality of wheat. Landraces of wheat, particularly from China (the secondary centre of origin of wheat), were analyzed and a new Pina-D1 allele was discovered, in addition to confirmation of several other reported alleles. Scanning electron microscopy analysis of various wheats with differences in their Pin alleles, sh…

Author: Ramalingam, Abirami
Publication year: 2012
Publication type: Thesis (PhD)
Status: Live|Last updated:February 23, 2017 2:26 PM
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