56 research outputs found
Increased acetylcholinesterase expression in bumble bees during neonicotinoid-coated corn sowing
While honey bee exposure to systemic insecticides has received much attention, impacts on wild pollinators have not been as widely studied. Neonicotinoids have been shown to increase acetylcholinesterase (AChE) activity in honey bees at sublethal doses. High AChE levels may therefore act as a biomarker of exposure to neonicotinoids. This two-year study focused on establishing whether bumble bees living and foraging in agricultural areas using neonicotinoid crop protection show early biochemical signs of intoxication. Bumble bee colonies (Bombus impatiens) were placed in two different agricultural cropping areas: 1) control (≥3 km from fields planted with neonicotinoid-treated seeds) or 2) exposed (within 500 m of fields planted with neonicotinoid-treated seeds) and maintained for the duration of corn sowing. As determined by Real Time qPCR, AChE mRNA expression was initially significantly higher in bumble bees from exposed sites, then decreased throughout the planting season to reach a similar endpoint to that of bumble bees from control sites. These findings suggest that exposure to neonicotinoid seed coating particles during the planting season can alter bumble bee neuronal activity. To our knowledge, this is the first study to report in situ that bumble bees living in agricultural areas exhibit signs of neonicotinoid intoxication
Revue d'histoire du Bas-Saint-Laurent, vol. 12 (3-4)
Mot de l'éditeur -- Au micro de CJBR -- La grande histoire de CJBR -- Jules-A. Brillant et le poste CJBR -- Avec CJBR, un bon en avant pour le Bas St-Laurent -- CJBR, l'école -- L'annonceur: un éducateur populaire -- Sandy Burgess : le journaliste que j'ai connu -- "Ce pays qui est le mien" -- Un demi-siècle d'information: que de nouvelles! -- Journaliste de père en fils à CJBR -- Le théâtre à CJBR -- 50 ans de musique à CJBR, le château fort de la mélodie française -- Poésie, théâtre, jazz et originalité avec Michel Garneau -- Les "Chroniques du dimanche", l'âge d'or de la critique culturelle à CJBR -- "Si CJBR m'était conté..." -- L'évolution technologique, un élément-clef de l'histoire des 50 ans de radiodiffusion -- La publicité à CJBR, quarante ans de croissance -- Des pionnières à CJBR -- 1958-1972, des années enrichissantes -- De Trois-Pistoles à Rimouski -- Le sport et son enracinement dans le milieu régional -- "Debout c'est l'heure", c'est Jean Brisson qui sonne le réveil -- "Par une belle journée de tempête" -- Et on repart vers la centain
The Murchison Widefield Array: Design Overview
The Murchison Widefield Array (MWA) is a dipole-based aperture array
synthesis telescope designed to operate in the 80-300 MHz frequency range. It
is capable of a wide range of science investigations, but is initially focused
on three key science projects. These are detection and characterization of
3-dimensional brightness temperature fluctuations in the 21cm line of neutral
hydrogen during the Epoch of Reionization (EoR) at redshifts from 6 to 10,
solar imaging and remote sensing of the inner heliosphere via propagation
effects on signals from distant background sources,and high-sensitivity
exploration of the variable radio sky. The array design features 8192
dual-polarization broad-band active dipoles, arranged into 512 tiles comprising
16 dipoles each. The tiles are quasi-randomly distributed over an aperture
1.5km in diameter, with a small number of outliers extending to 3km. All
tile-tile baselines are correlated in custom FPGA-based hardware, yielding a
Nyquist-sampled instantaneous monochromatic uv coverage and unprecedented point
spread function (PSF) quality. The correlated data are calibrated in real time
using novel position-dependent self-calibration algorithms. The array is
located in the Murchison region of outback Western Australia. This region is
characterized by extremely low population density and a superbly radio-quiet
environment,allowing full exploitation of the instrumental capabilities.Comment: 9 pages, 5 figures, 1 table. Accepted for publication in Proceedings
of the IEE
First spectroscopic imaging observations of the sun at low radio frequencies with the Murchison Widefield Array Prototype
We present the first spectroscopic images of solar radio transients from the prototype for the Murchison Widefield Array, observed on 2010 March 27. Our observations span the instantaneous frequency band 170.9- 201.6 MHz. Though our observing period is characterized as a period of "low" to "medium" activity, one broadband emission feature and numerous short-lived, narrowband, non-thermal emission features are evident. Our data represent a significant advance in low radio frequency solar imaging, enabling us to follow the spatial, spectral, and temporal evolution of events simultaneously and in unprecedented detail. The rich variety of features seen here reaffirms the coronal diagnostic capability of low radio frequency emission and provides an early glimpse of the nature of radio observations that will become available as the next generation of low-frequency radio interferometers come online over the next few years
On the maintenance of the axisymmetric part of the flow in the atmosphere
The maintenance of the axisymmetric component of the flow in the atmosphere is investigated by means of a steady-state, quasi-geostrophic formulation of the meteorological equations. It is shown that the meridional variations in the time-averaged axisymmetric variables can be expressed as the sum of three contributions, one being due to the eddy heat transport, another to the eddy momentum transport, and a third to the convective-radiative equilibrium temperature which enters the problem through the specification of a Newtonian form of diabatic heating. The contributions by the large scale eddies are evaluated through the use of observed values for the eddy heat and momentum transports.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43251/1/24_2004_Article_BF00878865.pd
Notes sur le pictural et le littéraire aux XVIIIe et XIXe siècles : le cas de Saint-Luc de La Corne
RésuméL'analyse de deux oeuvres picturales rattachées à l'écrivain Saint-Luc de La Corne (1711-1784) montre bien leur interaction avec le littéraire: son portrait miniature peint à Londres entre 1772 et 1784, qui peut être attribué à E. (Edward?) Vaugban, et la réinterprétation du Naufrage de L'Auguste proposée par Napoléon Bourassa pour décorer l'Hôtel du Parlement en 1883. Cette approche sera appliquée au corpus des autres écrivains étudiés par l'ALAQ, projet dont ces notes accompagnées de six illustrations donnent un bref aperçu.AbstractThe analysis of two pictorial works connected with the writer Saint-Luc de La Corne (1711-1784) demonstrate their interaction with the literary. They consist of a miniature portrait of La Corne painted in London between 1772 and 1784, which could be attributed to an E. (Edward?) Vaughan, and the reinterpretation of the wreck of the August proposed by Napoléon Bourassa for the decoration of the Parliement building in 1883. This approach will be applied to other writers studied by the ALAQ, a project of which these notes, accompanied by six illustrations, will give a general idea
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