661 research outputs found
Attention modulates spatial priority maps in the human occipital, parietal and frontal cortices.
Computational theories propose that attention modulates the topographical landscape of spatial 'priority' maps in regions of the visual cortex so that the location of an important object is associated with higher activation levels. Although studies of single-unit recordings have demonstrated attention-related increases in the gain of neural responses and changes in the size of spatial receptive fields, the net effect of these modulations on the topography of region-level priority maps has not been investigated. Here we used functional magnetic resonance imaging and a multivariate encoding model to reconstruct spatial representations of attended and ignored stimuli using activation patterns across entire visual areas. These reconstructed spatial representations reveal the influence of attention on the amplitude and size of stimulus representations within putative priority maps across the visual hierarchy. Our results suggest that attention increases the amplitude of stimulus representations in these spatial maps, particularly in higher visual areas, but does not substantively change their size
Colonel John Allan; a Maine Revolutionary Patriot
Full title: Colonel John Allan; a Maine Revolutionary Patriot Appointed in 1777 by the General Court of Massachusetts Bay Colony, to Command the Eastern Indians. Reprinted from Sprague\u27s Journal of Maine History, vol. 2, no. 5 (February 1915)
Sprague\u27s Journal of Maine History (Vol.XIV, No.2)
Sprague\u27s Journal of Maine History (Vol.XIV, No.2) April, May, June 1926.
Edited by John Francis Sprague.
Vol. 14, No. 2 (1926) Contents: History of the Chadwick Survey / Undeveloped Areas for Maine History Research / Fred Pike / Record of Marriages of Aroostook Pioneers / John C. Cross / Historical Notes about Farmington, Maine / Like a Bell\u27s Distant Tone / Relating to Farmington and Sandy River Region / Facts to be Remembered about the State of Maine / Passing of the Old Tanneries / School Department / Editorial Comment / Captain Silas Adams / Sayings of the Subscribershttps://digitalcommons.usm.maine.edu/me_collection/1029/thumbnail.jp
An Analysis of the Impact of an All Competitive Leasing System on Onshore Oil and Gas Leasing Revenue
Three Men From Maine : Sir William Pepperrell, Sir William Phips, James Sullivan and A Bit of Old England in New England
Three Men From Maine : Sir William Pepperrell, Sir William Phips, James Sullivan (by John Francis Sprague); and A Bit of Old England in New England (by Bertram E. Packard)
Sprague\u27s Journal of Maine History, Dover-Foxcroft, Maine (1924).
Contents: Sir William Pepperrell (1696-1759) / Sir William Phips (1651-1695) / James Sullivan (1744-1808) / A Bit of Old England in New England (Gardiner family)https://digitalcommons.usm.maine.edu/me_collection/1096/thumbnail.jp
A Twin-Embryo Abnormality in Maize
A mutant strain of corn obtained by ultra violet treatment has twin growing points in the embryo. The flattened emerging coleoptile is a continuous sheath, containing two distinct stem apices, each of which lays down a series of leaf primordia. Each growing point becomes encircled by its laterally overlapping young leaves. The procambium strands of the two young axes converge into the stele of the mesocotyl (first internode), which is common to the two potential stems
SAGP Program for 1962
Announcement of the meetings of the Society for Ancient Greek Philosophy with the Eastern Division of the American Philosophical Association and with the American Philological Association for 1962
The potential of alternative lighting-systems to suppress pre-harvest sexual maturation of 1+ Atlantic salmon (Salmo salar) post-smolts reared in commercial sea-cages
The aim of this study was to compare the efficiency of new candidate lighting-technologies (50W ‘blue’ light-emitting-diode (B, λmax = 465 nm); 232 W ‘green’ hot cathode, (G, λmax = 546 nm); 400 W ‘red’ tungsten-halogen, (R, λmax = 667 to 740 nm)) against a standard 400 W ‘white’ metal-halide used as control technology (C, broad spectrum) at suppressing sexual maturation of 1+ Atlantic salmon (Salmo salar) in sea-cages. A total of seven experimental set-ups were tested on a commercial-scale in three trials using a standardised photoperiod regime in the form of continuous artificial-light (LL) applied from winter to summer solstice during the second year at sea. The experimental stocks were raised under an ambient thermal regime that was similar across all trials. Technical performances (spectral output, light-attenuation and irradiance distance) of the individual light-units were measured and light-perception was assessed by quantifying plasma melatonin levels. Body-size parameters (BW, FL, K) were measured at the switch-on and turn-off of the photoperiod regimes. Maturation rates were estimated at the end of the light-treatments and at harvest. The B-unit provided the shortest effective irradiance distance (distance from the light-bulb to the minimum irradiance suppressing plasma melatonin to basal day-time level = 0.016 W m-2) but the longest relative to its energy consumption; while the G- and R-units did not offer a comparative advantage over the C-unit in that regard (B>C>G>R). Nocturnal plasma-melatonin and maturation rate decreased proportionally to the light-intensity provided using a range of technologies emitting distinct spectral profiles. Light-intensity rather than light-spectral composition appeared to be the prime parameter negatively affecting sexual maturation. Maximal suppression of maturation was observed in treatments depressing nocturnal plasma melatonin to a 1.2-fold but not to a 1.7-fold increase compared to daytime levels, confirming that a threshold level of light-irradiance is necessary to obtain the desired effect. Results suggest that this can be achieved under standard commercial practices by applying, over the photoperiod regime presently used, continuous artificial-illumination with an (electrical) energy consumption of 0.28 Wh m-3 generating a mean-irradiance of 0.012 W m-2 and providing a minimum volume of effective irradiance equivalent to 12% of the rearing-environment. Such a low volume of biologically effective irradiance was likely sufficient due to the strong photic attraction already reported in Atlantic salmon. Maximal suppression of pre-harvest sexual maturation can be achieved in the Atlantic salmon on-growing industry using alternative light-technologies. Present data provides methods and threshold values favouring the implementation of photoperiod-manipulation to suppress pre-harvest maturation at the most advantageous scale and cost
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