8 resultados para Number

em Brock University, Canada


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Identification of larval simuliids has always been difficult due to the morphological similarity many species bear to one another. For this reason all characters available have been drawn upon to aid in species identification, including head fan ray number. Even in light of an increasing body of anecdotal reports that head fan ray number is not fixed, it has continued to be used to aid species identification. In the current experiment simuliid larvae were reared under controlled laboratory conditions to last instar in one of three feeding regimes. Out of nine trials, the results of six showed a significant inverse relationship between feeding regime and head fan ray number. In addition to the laboratory experiments, larvae were also collected from the field over the course of the spring and summer, 1994. From these samples significant interspecific and intraspecific variations in head fan ray number were found both spatially and temporally within Algonquin Park. From these data it is concluded that head fan ray number for the species analysed is a developmentally plastic character, which varies in response to food availability. Furthermore, given the extreme variations in head fan ray number found in some species, I recommend that head fan ray number not be used as an aid to identification unless it can be shown to be a fixed character for the species in question.

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Mathematical predictions of flow conditions along a steep gradient rock bedded stream are examined. Stream gage discharge data and Manning's Equation are used to calculate alternative velocities, and subsequently Froude Numbers, assuming varying values of velocity coefficient, full depth or depth adjusted for vertical flow separation. Comparison of the results with photos show that Froude Numbers calculated from velocities derived from Manning's Equation, assuming a velocity coefficient of 1.30 and full depth, most accurately predict flow conditions, when supercritical flow is defined as Froude Number values above 0.84. Calculated Froude Number values between 0.8 and 1.1 correlate well with observed transitional flow, defined as the first appearance of small diagonal waves. Transitions from subcritical through transitional to clearly supercritical flow are predictable. Froude Number contour maps reveal a sinuous rise and fall of values reminiscent of pool riffle energy distribution.

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Full Title: Letters from the Secretary of War to the Committee of Ways and Means, in relation to the number of Militia called into the public service in 1813, to a provision for paying the bounties and premiums to soldiers lately authorized, and to the strength of the army March, 3, 1814. Read, and ordered to be printed. U.S. 13th Congress 2nd Session, 1813-1814. House.

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List of the number of loads dredged by Smiley’s Dredge since the 1st of October along the Welland Railway. This is addressed to S.D. Woodruff and signed by James Woodall of Lock No. 1. There are holes and stains in the document. Text is not affected, Jan. 12, 1859.

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Note regarding the number of days Fred Holmes was employed upon the Port Robinson and Thorold macadamized road during the months of July and August. This is signed by S.D. Woodruff and Fred Holmes, November, 1857.