762 research outputs found
Collectif CourtePointe, Pointe Saint-Charles : un quartier, des femmes, une histoire communautaire (Montréal, les Éditions du remue-ménage, 2006), 286 p.
French Canadians and the Beginning of the War of 1812: Revisiting the Lachine Riot
Historians have generally claimed that, during the War of 1812, unlike in earlier periods,
French Canadians eagerly rallied to the British cause and willingly fought to
defend British North America from American invasion. Nearly all studies of French-
Canadian participation in the war, however, focus on the Battle of Châteauguay in
1813, and few examine the first year of the war. A close look at French Canadians’
reactions to the outbreak of the War of 1812 would indicate that they were hardly
unanimous in their support. A detailed study of the largest and most violent act of
resistance — a riot that broke out at Lachine at the beginning of July 1812 — reveals
some of the reasons why so many habitants refused to perform their militia duty.Les historiens ont généralement soutenu que, pendant la guerre de 1812, contrairement
aux périodes précédentes, les Canadiens français se sont alliés avec enthousiasme
à la cause britannique et ont volontairement combattu pour défendre
l’Amérique du Nord britannique face à l’invasion américaine. Mais presque toutes
les études consacrées à la participation canadienne-française à la guerre portent sur
la bataille de Châteauguay, en 1813, et très peu sont consacrées à la première année
de la guerre. Un regard sur les réactions des Canadiens français suite au déclenchement
de la guerre de 1812 démontre que ceux-ci étaient loin d’offrir un appui
unanime. À travers une étude détaillée de l’acte de résistance le plus important et le
plus violent contre la guerre – l’émeute qu éclata à Lachine au début du mois de juillet
1812 – l’auteur cherche à élucider des raisons permettant d’expliquer pourquoi
les habitants refusèrent d’accomplir leur devoir militaire
Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate
Here we report the chemoselective synthesis of several important, climate relevant isoprene nitrates using silver nitrate to mediate a ’halide for nitrate’ substitution. Employing readily available starting materials, reagents and Horner–Wadsworth–Emmons chemistry the synthesis of easily separable, synthetically versatile ‘key building blocks’ (E)- and (Z)-3-methyl-4-chlorobut-2-en-1-ol as well as (E)- and (Z)-1-((2-methyl-4-bromobut-2-enyloxy)methyl)-4-methoxybenzene has been achieved using cheap, ’off the shelf’ materials. Exploiting their reactivity we have studied their ability to undergo an ‘allylic halide for allylic nitrate’ substitution reaction which we demonstrate generates (E)- and (Z)-3-methyl-4-hydroxybut-2-enyl nitrate, and (E)- and (Z)-2-methyl-4-hydroxybut-2-enyl nitrates (‘isoprene nitrates’) in 66–80% overall yields. Using NOESY experiments the elucidation of the carbon–carbon double bond configuration within the purified isoprene nitrates has been established. Further exemplifying our ‘halide for nitrate’ substitution chemistry we outline the straightforward transformation of (1R,2S)-(−)-myrtenol bromide into the previously unknown monoterpene nitrate (1R,2S)-(−)-myrtenol nitrate
A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system
Measures of exoplanet bulk densities indicate that small exoplanets with radius less than 3 Earth radii (R⊕) range from low-density sub-Neptunes containing volatile elements1 to higher-density rocky planets with Earth-like2 or iron-rich3 (Mercury-like) compositions. Such astonishing diversity in observed small exoplanet compositions may be the product of different initial conditions of the planet-formation process or different evolutionary paths that altered the planetary properties after formation4. Planet evolution may be especially affected by either photoevaporative mass loss induced by high stellar X-ray and extreme ultraviolet (XUV) flux5 or giant impacts6. Although there is some evidence for the former7,8, there are no unambiguous findings so far about the occurrence of giant impacts in an exoplanet system. Here, we characterize the two innermost planets of the compact and near-resonant system Kepler-107 (ref. 9). We show that they have nearly identical radii (about 1.5–1.6R⊕), but the outer planet Kepler-107 c is more than twice as dense (about 12.6 g cm–3) as the innermost Kepler-107 b (about 5.3 g cm−3). In consequence, Kepler-107 c must have a larger iron core fraction than Kepler-107 b. This imbalance cannot be explained by the stellar XUV irradiation, which would conversely make the more-irradiated and less-massive planet Kepler-107 b denser than Kepler-107 c. Instead, the dissimilar densities are consistent with a giant impact event on Kepler-107 c that would have stripped off part of its silicate mantle. This hypothesis is supported by theoretical predictions from collisional mantle stripping10, which match the mass and radius of Kepler-107 c
Evaluation of diffusive gradients in thin-films using a Diphonix® resin for monitoring dissolved uranium in natural waters
Commercially available Diphonix® resin (TrisKem International) was evaluated as a receiving phase for use with the diffusive gradients in thin-films (DGT) passive sampler for measuring uranium. This resin has a high partition coefficient for actinides and is used in the nuclear industry. Other resins used as receiving phases with DGT for measuring uranium have been prone to saturation and significant chemical interferences. The performance of the device was evaluated in the laboratory and in field trials. In laboratory experiments uptake of uranium (all 100% efficiency) by the resin was unaffected by varying pH (4–9), ionic strength (0.01–1.00 M, as NaNO3) and varying aqueous concentrations of Ca2+ (100–500 mg L−1) and HCO3− (100–500 mg L−1). Due to the high partition coefficient of Diphonex®, several elution techniques for uranium were evaluated. The optimal eluent mixture was 1 M NaOH/1 M H2O2, eluting 90% of the uranium from the resin. Uptake of uranium was linear (R2 = 0.99) over time (5 days) in laboratory experiments using artificial freshwater showing no saturation effects of the resin. In field deployments (River Lambourn, UK) the devices quantitatively accumulated uranium for up to 7 days. In both studies uptake of uranium matched that theoretically predicted for the DGT. Similar experiments in seawater did not follow the DGT theoretical uptake and the Diphonix® appeared to be capacity limited and also affected by matrix interferences. Isotopes of uranium (U235/U238) were measured in both environments with a precision and accuracy of 1.6–2.2% and 1.2–1.4%, respectively. This initial study shows the potential of using Diphonix®-DGT for monitoring of uranium in the aquatic environment
Vibro-Tactile Enhancement of Speech Intelligibility in Multi-talker Noise for Simulated Cochlear Implant Listening.
Many cochlear implant (CI) users achieve excellent speech understanding in acoustically quiet conditions but most perform poorly in the presence of background noise. An important contributor to this poor speech-in-noise performance is the limited transmission of low-frequency sound information through CIs. Recent work has suggested that tactile presentation of this low-frequency sound information could be used to improve speech-in-noise performance for CI users. Building on this work, we investigated whether vibro-tactile stimulation can improve speech intelligibility in multi-talker noise. The signal used for tactile stimulation was derived from the speech-in-noise using a computationally inexpensive algorithm. Eight normal-hearing participants listened to CI simulated speech-in-noise both with and without concurrent tactile stimulation of their fingertip. Participants' speech recognition performance was assessed before and after a training regime, which took place over 3 consecutive days and totaled around 30 min of exposure to CI-simulated speech-in-noise with concurrent tactile stimulation. Tactile stimulation was found to improve the intelligibility of speech in multi-talker noise, and this improvement was found to increase in size after training. Presentation of such tactile stimulation could be achieved by a compact, portable device and offer an inexpensive and noninvasive means for improving speech-in-noise performance in CI users
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