Nüvü : un bistro qui change d'atmosphère chaque soir

Un nouveau restaurant à concept, très tendance partout dans le monde, vient d'ouvrir ses portes dans le Village gai de Montréal : NÜVÜ, ...

Microsoft : y a-t-il péril en la demeure?

L'ancien vaisseau amiral du secteur de l'informatique est-il en train de sombrer ? De nombreuses brèches sont à colmater, disent les experts, mais la coque du navire est encore ...

Les marchés : Wall Street s'offre un gain de 3,5 % cette semaine

Wall Street a encaissé des gains d’environ 3,5 % lors d’une semaine où pour une rare fois, les données économiques publiées étaient davantage ...

SUPPLY CHAIN INNOVATION AS A KEY DRIVER OF PRODUCTIVITY AND COMPETITIVENESS - EXECUTIVE SUMMARY

This statement puts emphasis on the major role of logistics on productivity and competitiveness in manufacturing, wholesale and retail in the context of industrial globalization. After reviewing the best practices adopted by the top supply chains worldwide, the report examines the state of logistics (strengths, weaknesses, opportunities and threats) for companies located in the province of Québec, Canada, and sets recommendations to stimulate innovation in this area. These recommendations aim at helping companies catch up with their competitors and contributing to the implementation of adequate infrastructures.

Here is the position statement. The unabridged version is available in FRENCH on request (free of charge) or on this website : http://www.cst.gouv.qc.ca/L-innovat...

Please feel free to mention it in your newsletter and to forward it to anyone who might be interested.

Le Conseil se souviendra de Monsieur Germain Godbout

Tous les membres du Conseil de la science et de la technologie et du Secrétariat présentent leurs sincères condoléances à la famille et aux amis de Monsieur Germain Godbout, décédé le 10 juillet dernier.

Nous désirons réitérer notre reconnaissance à son égard pour son dévouement inépuisable à la cause de la promotion de la Science au Québec, ainsi qu'à sa contribution majeure aux travaux du Conseil, en particulier comme Directeur du grand projet Perspectives STS.

Amitiés sincères, les membres du Conseil et du Secrétariat

Nécrologie de Monsieur Godbout : http://necrologie.cyberpresse.ca/pr...

Le financement de l'innovation dans les entreprises
Le financement de l'innovation dans les entreprises est le document qui a servi de base à l'avis Pour un financement performant de l'innovation dans les entreprises parût le 7 juin dernier. Le Conseil de la science et de la technologie diffuse de ce fait l'étude afin de fournir une information beaucoup plus détaillée sur la problématique du financement de l'innovation dans les entreprises, plus particulièrement dans les petites et moyennes entreprises. L'étude examine tant la demande que l'offre de financement ainsi que les différentes interventions du gouvernement fédéral et du Québec pour tenter de pallier les lacunes du secteur privé.

Tetra Tech acquires EBA
EBA Engineering Consultants of Edmonton has been acquired by Tetra Tech, Inc. of Pasadena, California.In busin... [Full Story]

Infrastructure stimulus projects running close to the wire
The Parliamentary Budget Officer has reported back on the status of projects funded by Canada's Infrastructure... [Full Story]

New B.C. road includes $88 million for environmental and agricultural mitigation
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Better health through social networking
Scientists have long thought that social networks featuring many distant connections, or “long ties” — where individuals know a lot of people, but not well — produce large-scale changes most quickly. But in a new study, Damon Centola, an assistant professor of system dynamics and economic sociology at the MIT Sloan School of Management, has reached a different conclusion: People are more likely to acquire new health practices while living in networks with dense clusters of connections — that is, when in close contact with people they already know well.

Researchers often regard these dense clusters of connections to be redundant when it comes to spreading information; networks featuring such clusters are considered less efficient than networks with a greater proportion of long ties. But getting people to change ingrained habits, Centola found, requires the extra reinforcement that comes from those redundancies. In other words, people need to hear a new idea multiple times before making a change.

“For about 35 years, wisdom in the social sciences has been that the more long ties there are in a network, the faster a thing will spread,” says Centola. “It’s startling to see that this is not always the case.” Centola’s paper on the subject, “The Spread of Behavior in an Online Social Network Experiment,” is published in the Sept. 3 issue of the journal Science.

The buddy system

To see what difference the form of a social network makes, Centola ran a series of experiments using an Internet-based health community he developed. The 1,528 people in the study had anonymous online profiles and a series of health interests; they were matched with other participants sharing the same interests — “health buddies,” as Centola calls them in the paper. Participants received e-mail updates notifying them about the activities of their health buddies.

Centola placed participants into one of two distinct kinds of networks — those oriented around long ties, and those featuring larger clusters of people — and ran six separate trials over a period of a few weeks to see which groups were more likely to register for an online health forum website offering ratings of health resources.

Overall, 54 percent of the people in clustered networks registered for the health forum, compared to 38 percent in the networks oriented around longer ties; the rate of adoption in the clustered networks was also four times as fast. Moreover, people were more likely to participate regularly in the health forum if they had more health buddies who registered for it. Only 15 percent of forum participants with one friend in the forum returned to it, but more than 30 percent of subjects with two friends returned to it, and over 40 percent with three friends in the forum made repeat visits.

“Social reinforcement from multiple health buddies made participants much more willing to adopt the behavior,” notes Centola in the paper. Significantly, he writes, this effect on individuals “translates into a system-level phenomenon whereby large-scale diffusion can reach more people, and spread more quickly, in clustered networks than in random networks.”

Centola thinks the existence of this effect has important implications for health officials. A “simple contagion,” in network theory, can spread with a single contact; a “complex contagion” requires multiple exposures for transmission. A disease, Centola suggests, can spread as a simple contagion, but behavior that can prevent the disease — such as going to a clinic for a vaccination — might spread only as a complex contagion, thus needing to be spurred by reinforcement from multiple neighbors in a social network.

“If there is a significant difference between simple and complex contagions, that actually matters for our policy interventions,” says Centola. The public promotion of screenings and other forms of disease prevention might best be aimed at communities and groups that act as closely clustered networks.

Studying communities, online and off

Colleagues in the field find the study to be of both theoretical and practical interest. “It’s interesting work because it shows that for the diffusion of certain kinds of things, you really need reinforcing,” says David Lazer, an associate professor of public policy at Harvard’s Kennedy School of Government. “You need wide bridges to transmit complex information like health data, and that is different from the traditional picture of how things spread in a network.”

As Centola acknowledges, the study has limitations. Joining an online health forum has little cost in time or money, unlike many other kinds of health behavior, from vaccinations to changing one’s diet or adopting an exercise routine. “Getting a colonoscopy is hard,” Centola says. “Just hearing about it is probably not going to convince you to do it.” The rate of adoption would likely vary widely for many forms of health behavior, and be relatively low when notable costs are involved.

On the other hand, Centola notes, the existence of those costs implies that social reinforcement, such as having multiple friends and relatives who get colonoscopies, may be especially important. “These redundant signals are necessary to make people adopt the behavior,” Centola says.  

Further fieldwork may help determine how resistant people are to changing particular forms of health behavior. “One thing this study begs, in a good way, is more research in natural settings,” says Lazer. To see the effectiveness of public-health measures, he suggests, “You might try to target two neighborhoods in different ways, and then assess which is more effective.”

For his part, Centola thinks there is also further work to be done evaluating the effects of online social networks on behavior. “There is a natural implication in terms of what this means for designing online communities,” says Centola. His new research, building on his current paper, aims to find new designs for online communities, in order to promote good health practices.

Toward greener chemistry
Phosphorus, a mineral element found in rocks and bone, is a critical ingredient in fertilizers, pesticides, detergents and other industrial and household chemicals. Once phosphorus is mined from rocks, getting it into these products is hazardous and expensive, and chemists have been trying to streamline the process for decades.

MIT chemistry professor Christopher Cummins and one of his graduate students, Daniel Tofan, have developed a new way to attach phosphorus to organic compounds by first splitting the phosphorus with ultraviolet light. Their method, described in the Aug. 26 online edition of Angewandte Chemie, eliminates the need for chlorine, which is usually required for such reactions and poses health risks to workers handling the chemicals.

Guy Bertrand, chemistry professor at the University of California at Riverside, says the beauty of the discovery is its simplicity. “It is amazing to realize that nobody thought earlier about such a simple approach to incorporate phosphorus into organic molecules,” he says. “Such a synthetic approach to organophosphorus compounds is indeed urgent, since the old (chlorine)-based phosphorus chemistry has a lot of undesirable consequences on our environment.”

While the new reaction cannot produce the quantities needed for large-scale production of phosphorus compounds, it opens the door to a new field of research that could lead to such industrial applications, says Bertrand, who was not involved in the research.

Extracting phosphorus

Most natural phosphorus deposits come from fossilized animal skeletons, which are especially abundant in dried-up seabeds. Those phosphorus deposits exist as phosphate rock, which usually includes impurities such as calcium and other metals that must be removed.

Purifying the rock produces white phosphorus, a molecule containing four phosphorus atoms. White phosphorous is tetrahedral, meaning it resembles a four-cornered pyramid in which each corner atom is bound to the other three. Known as P₄, white phosphorus is the most stable form of molecular phosphorus. (There are also several polymeric forms, the most common of which are black and red phosphorus, which consist of long chains of broken phosphorus tetrahedrons.)

For most industrial uses, phosphorus has to be attached one atom at a time, so single atoms must be detached from the P₄ molecule. This is usually done in two steps. First, three of the atoms in P₄ are replaced with chlorine, resulting in PCl₃ — a phosphorus atom bound to three chlorine atoms.

Those chlorine atoms are then displaced by organic (carbon-containing) molecules, creating a wide variety of organophosphorus compounds such as those found in pesticides. However, this procedure is both wasteful and dangerous — chlorine gas was used as a chemical weapon during World War I — so chemists have been trying to find new ways to bind phosphorus to organic compounds without using chlorine.

A new reaction

Cummins has long been fascinated with phosphorus, in part because of its unusual tetrahedral P₄ formation. Phosphorus is in the same column of the periodic table as nitrogen, whose most stable form is N₂, so chemists expected that phosphorus might form a stable P₂ structure. However, that is not the case.

For the past few years, Cummins’ research group has been looking for ways to break P₄ into P₂ in hopes of attaching the smaller phosphorus molecule to organic compounds. In the new study, Cummins drew inspiration from a long overlooked paper, published in 1937, which demonstrated that P₄ could be broken into two molecules of P₂ with ultraviolet light. In that older study, P₂ then polymerized into red phosphorus.

Cummins decided to see what would happen if he broke apart P₄ with UV light in the presence of organic molecules that have an unsaturated carbon-carbon bond (meaning those carbon atoms are able to grab onto other atoms and form new bonds). After 12 hours of UV exposure, he found that a compound called a tetra-organo diphosphane had formed, which includes two atoms of phosphorus attached to two molecules of the organic compound.

This suggests, but does not conclusively prove, that P₂ forms and then immediately bonds to the organic molecule. In future studies, Cummins hopes to directly observe the P₂ molecule, if it is indeed present.

Cummins also plans to investigate what other organophosphorus compounds can be synthesized with ultraviolet light, including metallic compounds. He has already created a nickel-containing organophosphorus molecule, which could have applications in electronics.

Supercomputing on a cell phone
Many engineering disciplines rely on supercomputers to simulate complicated physical phenomena — how cracks form in building materials, for instance, or fluids flow through irregular channels. Now, researchers in MIT’s Department of Mechanical Engineering have developed software that can perform such simulations on an ordinary smart phone. Although the current version of the software is for demonstration purposes, the work could lead to applications that let engineers perform complicated calculations in the field, and even to better control systems for vehicles or robotic systems.

The new software works in cases where the general form of a problem is known in advance, but not the particulars. For instance, says Phuong Huynh, a postdoc who worked on the project, a computer simulation of fluid flow around an obstacle in a pipe could depend on a single parameter: the radius of the obstacle. But for a given value of the parameter, calculating the fluid flow could take an hour on a supercomputer with 500 processing units. The researchers’ new software can provide a very good approximation of the same calculation in a matter of seconds.

“This is a very relevant situation,” says David Knezevic, another postdoc in the department who helped lead the project. “Often in engineering contexts, you know a priori that your problem is parameterized, but you don’t know until you get into the field what parameters you’re interested in.”

Each new problem the researchers’ software is called upon to solve requires its own mathematical model. The models, however, take up very little space in memory: A cell phone could hold thousands of them. The software, which is available for download, comes preloaded with models for nine problems, including heat propagation in objects of several different shapes, fluid flow around a spherical obstacle, and the effects of forces applied to a cracked pillar. As the researchers develop models for new classes of problems, they post them on a server, from which they can be downloaded.

Advance work

But while the models are small, creating them is a complicated process that does in fact require a supercomputer. “We’re not trying to replace a supercomputer,” Knezevic says. “This is a model of computation that works in conjunction with supercomputing. And the supercomputer is indispensable.”

Knezevic, his fellow postdoc Phuong Huynh, Ford Professor of Engineering Anthony T. Patera, and John Peterson of the Texas Advanced Computer Center describe their approach in a forthcoming issue of the journal Computers and Fluids. Once they have identified a parameterized problem, they use a supercomputer to solve it for somewhere between 10 and 50 different sets of values. Those values, however, are carefully chosen to map out a large space of possible solutions to the problem. The model downloaded to a smart phone finds an approximate solution for a new set of parameters by reference to the precomputed solutions.

The key to the system, Knezevic says, is the ability to quantify the degree of error in an approximation of a supercomputing calculation, a subject that Patera has been researching for almost a decade. As the researchers build a problem model, they select parameters that will successively minimize error, according to analytic techniques Patera helped developed. The calculation of error bounds is also a feature of the phone application itself. For each approximate solution of a parameterized problem, the app also displays the margin of error. The user can opt to trade speed of computation for a higher margin of error, but the app can generally get the error under 1 percent in less than a second.

Turning the tables

While the researchers’ software can calculate the behavior of a physical system on the basis of its parameters, it could prove even more useful by doing the opposite: calculating the parameters of a physical system on the basis of its behavior. Instead of, say, calculating fluid flow around an obstacle based on the obstacle’s size, the software could calculate the size of the obstacle based on measurements of the fluid flow at the end of a pipe. Ordinarily, that would require several different computations on a supercomputer, trying out several different sets of parameters. But if testing, say, 30 options on a supercomputer would take 30 hours, it might take 30 seconds on a phone. Indeed, the researchers have already developed a second application that calculates such “inverse problems.”

In the same way that a simulation of a physical system describes its behavior on the basis of parametric measurements, control systems, of the type that govern, say, automotive brake systems or autonomous robots, determine devices’ behavior on the basis of sensor measurements. Control-systems researchers spend a great deal of energy trying to come up with practical approximations of complex physics in order to make their systems responsive enough to work in real time. But Knezevic, Huynh and Patera’s approach could make those approximations both more accurate and easier to calculate.

Max Gunzberger, Frances Eppes Eminent Professor of Scientific Computing at Florida State University says that the MIT researchers’ work has a “cuteness aspect” that has already won it some attention. But “once you get over the cuteness factor,” he says, “if you talk about serious science or serious engineering, there’s a potential there.” Gunzberger points out that while the researchers’ demo concentrates on fluid mechanics, “there’s lots of other problems that their approach can be applied to. They built the structure that they themselves or others can start using to solve problems in different application areas.”