8,105 research outputs found

    L’évolution récente de l’utilisation du sol sur la rive nord du Saint-Laurent entre Québec et Montréal

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    In recent years, the face of much of rural Québec bas undergone a series of important transformations : vast areas of marginal farmland have either been abandoned or reforested ; large tracts of cleared land in the Saint Lawrence lowlands have been converted from general farming to specialty crops ; several of these areas of specialty crops are now being swallowed up by urban expansion ; the Laurentide hills and large sections of the Eastern Townships area are rapidly being transformed into sprawling tourist playgrounds. With the aid of 1964 air photos and 1965 land use data the authors record and briefly discuss some of the more striking trends in the evolution of rural land use patterns in the area between Montréal and Québec City, on the north shore of the Saint Lawrence River

    X,Y,Z-Waves: Extended Structures in Nonlinear Lattices

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    Motivated by recent experimental and theoretical results on optical X-waves, we propose a new type of waveforms in 2D and 3D discrete media -- multi-legged extended nonlinear structures (ENS), built as arrays of lattice solitons (tiles or stones, in the 2D and 3D cases, respectively). First, we study the stability of the tiles and stones analytically, and then extend them numerically to complete ENS forms for both 2D and 3D lattices. The predicted patterns are relevant to a variety of physical settings, such as Bose-Einstein condensates in deep optical lattices, lattices built of microresonators, photorefractive crystals with optically induced lattices (in the 2D case) and others.Comment: 4 pages, 4 figure

    Multicenter multidisciplinary training program for chronic low back pain: French experience of the Renodos back pain network (RĂ©seau Nord-Pas-de-Calais du DOS)

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    AbstractObjectivesTo evaluate the short- and long-term effectiveness of the multidisciplinary training program (MTP). To show the benefits which the network organization brings to the treatment of chronic low back pain (CLPB).MethodsThe member centres of the Renodos back pain network included 748 subjects in the MTP. The centres used a common evaluation protocol including pain and quality of life visual analogue scales (VAS), fingertip-to-floor distance (FFD), muscle isometric endurance tests, Roland-Morris Disability Questionnaire (RDQ), the Dallas Pain Questionnaire (DPQ) and the Hospital Anxiety Depression (HAD) scale. Measurements were carried out before (T0) and immediately after (T1) the intervention, and at the 3-, 6-, 12-month (T3, T6, T12) follow-up visits.ResultsStatistically discernible improvement occurred for men and women on every outcome measure from before to after the MTP (T0–T1, p<0.0001). This improvement obtained at T1 was maintained for most of the outcome measures throughout the 12-month follow-up. However, the pain intensity and isometric muscle endurance times showed significant negative evolution. Significant differences between genders were found for the trunk flexibility measurement (FFD), the isometric endurance time of the quadratus lumborum muscle, the RDQ and the HAD depression. There was no time–gender interaction.ConclusionThe MTP was effective in reducing back pain intensity, functional disability, symptoms of anxiety and depression and in improving quality of life, flexibility and isometric muscle endurance time. It was possible to propose the MTP to both men and women. A network organization effectively contributes to the harmonization of evaluation methods and brings coherence to the treatment of CLBP patients

    Experimental phase diagram of moving vortices

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    In the mixed state of type II superconductors, vortices penetrate the sample and form a correlated system due to the screening of supercurrents around them. Interestingly, we can study this correlated system as a function of density and driving force. The density, for instance, is controlled by the magnetic field, B, whereas a current density j acts as a driving force F=jxB on all vortices. The free motion of vortices is inhibited by the presence of an underlying potential, which tends to pin the vortices. Hence, to minimize the pinning strength we studied a superconducting glass in which the depinning current is 10 to 1000 times smaller than in previous studies, which enables us to map out the complete phase diagram in this new regime. The diagram is obtained as a function of B, driving current and temperature and led a remarkable set of new results, which includes a huge peak effect, an additional reentrant depinning phase and a driving force induced pinning phase.Comment: 4 page

    A 100-element HBT grid amplifier

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    A 100-element 10-GHz grid amplifier has been developed. The active devices in the grid are chips with heterojunction-bipolar-transistor (HBT) differential pairs. The metal grid pattern was empirically designed to provide effective coupling between the HBTs and free space. Two independent measurements, one with focusing lenses and the other without, were used to characterize the grid. In each case, the peak gain was 10 dB at 10 GHz with a 3-dB bandwidth of 1 GHz. The input and output return losses were better than 15 dB at 10 GHz. The maximum output power was 450 mW, and the minimum noise figure was 7 dB. By varying the bias, a signal could be amplitude modulated with a modulation index as large as 0.65. Tests show that the grid was quite tolerant of failures-the output power dropped by only 1 dB when 10% of the inputs were detuned. The grid amplifier is a multimode device that amplifies beams of different shapes and angles. Beams with incidence angles up to 30° were amplified with less than a 3-dB drop in gain

    Dense Quark Matter Conductivity in Ultra-Intense Magnetic Field

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    Heavy-ion collisions generate a huge magnetic field of the order of 1018G10^{18} G for the duration of about 0.2 fm/c. This time may become an order of magnitude longer if the electrical conductivity of quark matter is large. We calculate the conductivity in the regime of high density and show that contrary to naive expectations it only weakly depends on the MF.Comment: 3 pages, 0 figure

    PMH11 RATIONAL CHOICE OF TREATMENT STRATEGY IN MODERATE TO SEVERE ALZHEIMER'S DISEASE PATIENTS LIVING IN CANADA

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    Proposal of a CLT reinforcement of old timber floors

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    Despite the fact that, from the mechanical point of view, there is no ageing issues of timber elements when they are properly used, many old timber structures require important interventions because of changes in uses (which modifies the regulating rules for example), of material decay (misuse of timber) or possibly of a faulty design or construction. In particular, timber floors in old structures often present large deflections and most the time had been designed for a maximum load much lower than the one prescribed by contemporary rules. After an introduction about timber floors and a short review about the reinforcement technics that exist, the present paper presents a new proposal for their reinforcement. The solution developed in the present paper uses a Cross Laminated Timber (CLT) panel screwed over the existing floor, keeping a small gap between the panel and the existing joists. In this way, the new “composite” floor presents higher stiffness and the gap is used for horizontal line runs. For the design of such a “composite floor”, modified Johanssen’s equations (including the gap between the CLT panel and the joists) are proposed and their application on a case study is presented.- (undefined
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