University of Sydney

About: University of Sydney is a education organization based out in Sydney, New South Wales, Australia. It is known for research contribution in the topics: Population & Health care. The organization has 61532 authors who have published 187345 publications receiving 6114218 citations. The organization is also known as: Sydney University & USyd.

Green light emission in silicon through slow-light enhanced third-harmonic generation in photonic-crystal waveguides

Abstract: Slow light has attracted significant interest recently as a potential solution for optical delay lines and time-domain optical signal processing1,2. Perhaps even more significant is the possibility of dramatically enhancing nonlinear optical effects3,4 due to the spatial compression of optical energy5,6,7. Two-dimensional silicon photonic-crystal waveguides have proven to be a powerful platform for realizing slow light, being compatible with on-chip integration and offering wide-bandwidth and dispersion-free propagation2. Here, we report the slow-light enhancement of a nonlinear optical process in a two-dimensional silicon photonic-crystal waveguide. We observe visible third-harmonic-generation at a wavelength of 520 nm with only a few watts of peak power, and demonstrate strong third-harmonic-generation enhancement due to the reduced group velocity of the near-infrared pump signal. This demonstrates yet another unexpected nonlinear function realized in a CMOS-compatible silicon waveguide. The use of slow light for enhancing a nonlinear optical process in a two-dimensional silicon photonic-crystal waveguide is demonstrated. More specifically, green emission by third-harmonic generation is obtained, highlighting yet another functionality of silicon photonics chips.

Neglecting legumes has compromised human health and sustainable food production

Abstract: The United Nations declared 2016 as the International Year of Pulses (grain legumes) under the banner ‘nutritious seeds for a sustainable future’. A second green revolution is required to ensure food and nutritional security in the face of global climate change. Grain legumes provide an unparalleled solution to this problem because of their inherent capacity for symbiotic atmospheric nitrogen fixation, which provides economically sustainable advantages for farming. In addition, a legume-rich diet has health benefits for humans and livestock alike. However, grain legumes form only a minor part of most current human diets, and legume crops are greatly under-used. Food security and soil fertility could be significantly improved by greater grain legume usage and increased improvement of a range of grain legumes. The current lack of coordinated focus on grain legumes has compromised human health, nutritional security and sustainable food production.

Isotopic evidence for microbial sulphate reduction in the early Archaean era

Abstract: Sulphate-reducing microbes affect the modern sulphur cycle, and may be quite ancient1,2, though when they evolved is uncertain. These organisms produce sulphide while oxidizing organic matter or hydrogen with sulphate3. At sulphate concentrations greater than 1 mM, the sulphides are isotopically fractionated (depleted in 34S) by 10–40‰ compared to the sulphate, with fractionations decreasing to near 0‰ at lower concentrations2,4,5,6. The isotope record of sedimentary sulphides shows large fractionations relative to seawater sulphate by 2.7 Gyr ago, indicating microbial sulphate reduction7. In older rocks, however, much smaller fractionations are of equivocal origin, possibly biogenic but also possibly volcanogenic2,8,9,10. Here we report microscopic sulphides in ∼3.47-Gyr-old barites from North Pole, Australia, with maximum fractionations of 21.1‰, about a mean of 11.6‰, clearly indicating microbial sulphate reduction. Our results extend the geological record of microbial sulphate reduction back more than 750 million years, and represent direct evidence of an early specific metabolic pathway—allowing time calibration of a deep node on the tree of life.

Masculinities and Globalization

Abstract: Recent social science research has made important changes in our understanding of masculinities and men's gender practices, emphasizing the plurality and hierarchy of masculinities, and their collective and dynamic character. These gains have been achieved mainly by close-focus research methods. But in a globalizing world, we must pay attention also to very large scale structures. An understanding of the world gender order is a necessary basis for thinking about men and masculinities globally. We can trace the emergence of globalizing masculinities at different stages of the history of the world gender order. Hegemony in the contemporary gender order is connected with patterns of trade, investment, and communication dominated by the North. A transnational business masculinity, institutionally based in multinational corporations and global finance markets, is arguably the emerging dominant form on a world scale.