Soderstrom O.,University of Neuchatel |
Singapore Journal of Tropical Geography | Year: 2013
This paper analyses the recent developments in public space policy in the city of Hanoi, Vietnam. It has three aims. The first is to look at a potentially progressive urban policy in contrast to most work on 'policies in motion' that has primarily been concerned with neoliberal policies. The second is to put the process of public space policymaking in Hanoi in historical and cultural perspective. We therefore describe public space in Hanoi as historically constituted by different layers of meaning and physical urban patterns. The paper's third aim is to analyse the translocal connections involved in a policy that is still in the making, and therefore characterized by a series of 'loose threads'. We show how different types of connections - policy mobility, topological relations and inter-referencing - relate Hanoi to multiple locales elsewhere. The conclusion reflects on the 'politics of reception' showing how analysing a policy in the making develops a critical analysis of policies in motion. © 2013 The Authors Singapore Journal of Tropical Geography © 2013 Department of Geography, National University of Singapore and Wiley Publishing Asia Pty Ltd. Source
Kaur S.,Banaras Hindu University |
Critical Reviews in Microbiology | Year: 2014
Among the biopolymers, chitin and its derivative chitosan (CTS) have been receiving increasing attention. Both are composed of randomly distributed β-(1-4)-linked d-glucosamine and N-acetyl glucosamine units. On commercial scale, CTS is mainly obtained from the crustacean shells. The chemical methods employed for extraction of CTS from crustacean shells are laden with many disadvantages. Waste fungal biomass represents a potential biological source of CTS, in fact with superior physico-chemical properties, such as high degree of deacetylation, low molecular weight, devoid of protein contamination and high bioactivity. Researchers around the globe are attempting to commercialize CTS production and extraction from fungal sources. Fungi are promising and environmentally benign source of CTS and they have the potential to completely replace crustacean-derived CTS. Waste fungal biomass resulting from various pharmaceutical and biotechnological industries is grown on inexpensive agro-industrial wastes and its by-products are a rich and inexpensive source of CTS. CTS is emerging as an important natural polymer having broad range of applications in different fields. In this context, the present review discusses the potential sources of CTS and their advantages and disadvantages. This review also deals with potential applications of CTS in different fields. Finally, the various attributes of CTS sought in different applications are discussed. © 2014 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted. Source
Godin B.,INRS |
Lane J.P.,State University of New York at Buffalo
Science Technology and Human Values | Year: 2013
Much has been written about the linear model of innovation. While it may have been the dominant model used to explain technological innovation for decades, alternatives did exist. One such alternative-generally discussed as being the exact opposite of the linear model-is the demand-pull model. Beginning in the 1960s, people from different disciplines started looking at technological innovation from a demand rather than a supply perspective. The theory was that technological innovation is stimulated by market demand rather than by scientific discoveries. However, few traces of the demand-pull model remain in the literature today. This article looks at what happened to the demand-pull model from a historical perspective, at three points in time: birth, crystallization, and death. It suggests that the idea of demand as a factor explaining technological innovation emerged in the 1960s, was formalized into models in the 1970-1980s, then got integrated into "multidimensional" models. From then on, the demand-pull model disappeared from the literature, existing only as an object of the past, like the linear model of innovation. © The Author(s) 2013. Source
Home > Press > Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers Abstract: Quantum mechanics, with its counter-intuitive rules for describing the behavior of tiny particles like photons and atoms, holds great promise for profound advances in the security and speed of how we communicate and compute. Now an international team of researchers has built a chip that generates multiple frequencies from a robust quantum system that produces time-bin entangled photons. In contrast to other quantum state realizations, entangled photons don't need bulky equipment to keep them in their quantum state, and they can transmit quantum information across long distances. The new device creates entangled photons that span the traditional telecommunications spectrum, making it appealing for multi-channel quantum communication and more powerful quantum computers. "The advantages of our chip are that it's compact and cheap. It's also unique that it operates on multiple channels," said Michael Kues, Institut National de la Recherche Scientifique (INRS), University of Quebec, Canada. The researchers will present their results at the Conference on Lasers and Electro-Optics (CLEO), which is held June 5 -10 in San Jose, California. The basis of quantum communications and computing lies in qubits, the quantum equivalent of classical bits. Instead of representing a one or a zero, qubits can exhibit an unusual property called superposition to represent both numbers simultaneously. In order to take full advantage of superposition to perform difficult calculations or send information securely, another weird quantum mechanical property called entanglement enters the picture. Entanglement was famously called "spooky action at a distance" by Albert Einstein. It links particles so that measurements on one instantaneously affect the other. Kues and his colleagues used photons to realize their qubits and entangled them by sending two short laser pulses through an interferometer, a device that directs light beams along different paths and then recombines them, to generate double pulses. To generate multiple frequencies, Kres and his colleagues sent the pulses through a tiny ring, called a microring resonator. The resonator generates photon pairs on a series of discrete frequencies, using spontaneous form-wave mixing, thus creating a frequency comb. The interferometer the team used has one long arm and one short arm, and when a single photon comes out of the system, it is in a superposition of time states, as if it traveled through both the long arm and the short arm simultaneously. Time-bin entanglement is a particularly robust form of photon entanglement. Photons can also have their polarization entangled, but waveguides and other types of optical equipment may alter polarization states. Other research groups have generated time-bin entangled photons, but Kues and his colleagues are the first to create photons with multiple frequencies using the same chip. This feature can enable multiplexed and multi-channel quantum communications and increased quantum computation information capacity. Kues notes that the chip could improve quantum key distribution, a process that lets two parties share a secret key to encrypt messages with theoretically unbreakable security. It could also serve as a component of a future quantum computer. "In the future you may have a computer with both quantum and classical capabilities. The quantum part would only be used to solve specific problems that are difficult for classical computers," said Roberto Morandotti, a physicist at INRS and leader of the group that developed the chip. Before quantum computers reach a desktop near you, they need to be scaled down, in terms of size, and scaled up, in terms of computing power. Morandotti, Kues and colleagues think their chip is a step in the right direction. The team is currently working to integrate the lasers, interferometer, and microring resonator of the device into a standard photonic chip, to build logic gates for quantum state manipulation, and to increase the degree of entanglement, which is a measure of the strength of the link between particles. ### About the Presentation The presentation, "Integrated Quantum Frequency Comb Source of Entangled Qubits," by Christian Reimer, Michael Kues, Piotr Roztocki, Benjamin Wetzel, Yaron Bromberg, Fabio Grazioso, Brent E. Little, Sai T. Chu, David J. Moss, Lucia Caspani and Roberto Morandotti will take place from 17:00 - 17:15 on Thursday, June 9, 2016 in the Executive Ballroom 210A of the San Jose Convention Center, San Jose, California, USA. Media Registration: A media room for credentialed press and analysts will be located on-site in the San Jose Convention Center, 5-10 June 2016. Media interested in attending the event should register on the CLEO website media center: Media Center. About CLEO With a distinguished history as the industry's leading event on laser science, the Conference on Lasers and Electro-Optics (CLEO) is the premier international forum for scientific and technical optics, uniting the fields of lasers and opto-electronics by bringing together all aspects of laser technology, from basic research to industry applications. CLEO: Expo showcases the latest products and applications from more than 300 participating companies from around the world, providing hands-on demonstrations of the latest market innovations and applications. The Expo also offers valuable on-floor programming, including Market Focus and the Technology Transfer program. Managed by The Optical Society (OSA) and sponsored by the American Physical Society's (APS) Laser Science Division, IEEE Photonics Society and OSA, CLEO provides the full range of critical developments in the field, showcasing the most significant milestones from laboratory to marketplace. With an unparalleled breadth and depth of coverage, CLEO connects all of the critical vertical markets in lasers and electro-optics. For more information, visit the event website at www.cleoconference.org. CLEO 2016 takes place 5 - 10 June 2016 at the San Jose Convention Center, San Jose, California, USA. Follow developments and updates on CLEO 2016 on Twitter @CLEOConf, #CLEO16. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Home > Press > Promising new approach for controlled fabrication of carbon nanostructures Abstract: An international team of researchers including Professor Federico Rosei and members of his group at INRS has developed a new strategy for fabricating atomically controlled carbon nanostructures used in molecular carbon-based electronics. An article just published in the prestigious journal Nature Communications presents their findings: the complete electronic structure of a conjugated organic polymer, and the influence of the substrate on its electronic properties. The researchers combined two procedures previously developed in Professor Rosei's lab--molecular self-assembly and chain polymerization--to produce a network of long-range poly(para-phenylene) (PPP) nanowires on a copper (Cu) surface. Using advanced technologies such as scanning tunneling microscopy and photoelectron spectroscopy as well as theoretical models, they were able to describe the morphology and electronic structure of these nanostructures. "We provide a complete description of the band structure and also highlight the strong interaction between the polymer and the substrate, which explains both the decreased bandgap and the metallic nature of the new chains. Even with this hybridization, the PPP bands display a quasi one-dimensional dispersion in conductive polymeric nanowires," said Professor Federico Rosei, one of the authors of the study. Although further research is needed to fully describe the electronic properties of these nanostructures, the polymer's dispersion provides a spectroscopic record of the polymerization process of certain types of molecules on gold, silver, copper, and other surfaces. It's a promising approach for similar semiconductor studies--an essential step in the development of actual devices. The results of the study could be used in designing organic nanostructures, with significant potential applications in nanoelectronics, including photovoltaic devices, field-effect transistors, light-emitting diodes, and sensors. About INRS Institut national de recherche scientifique (INRS) is a graduate-level research and training university and ranks first in Canada for research intensity (average funding per professor). INRS brings together some 150 professors and close to 700 students and postdoctoral fellows at its four centres in Montreal, Quebec City, Laval, and Varennes. Its basic research is essential to the advancement of science in Quebec and internationally, and its research teams play a key role in the development of concrete solutions to the problems faced by our society. For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.