Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level from London to St. Catharines, April 1847.

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level from London to St. Catharines. This sheet is signed by S.D. Woodruff, Jan. 11, 1847.

Approximate cost of completing the railway from Port Dalhousie to St. Catharines and an estimate of the cost of the piers at Port Dalhousie signed by William Hamilton Merritt

Approximate cost of completing the railway from Port Dalhousie to St. Catharines and an estimate of the cost of the piers at Port Dalhousie signed by William Hamilton Merritt (5 pages, handwritten), July 8, 1854.

Approximate estimate of the cost of completing the Port Dalhousie Railway to the Grand Central Railway Station at Lock 12

Approximate estimate of the cost of completing the Port Dalhousie Railway to the Grand Central Railway Station at Lock 12. This document is badly torn and burned but most of the text is legible, July 14, 1854.

Estimated cost of the Port Dalhousie and Thorold Railway sent to George Rykert by S.D. Woodruff

Estimated cost of the Port Dalhousie and Thorold Railway sent to George Rykert by S.D. Woodruff, Aug. 5, 1854.

Approximate estimate of the cost of constructing and completing the Port Dalhousie and Thorold Railway to St. Catharines

Approximate estimate of the cost of constructing and completing the Port Dalhousie and Thorold Railway to St. Catharines signed by S.D. Woodruff (2 pages, handwritten), Jan. 8, 1855.

Cost of the railway from Port Dalhousie to St. Catharines

Cost of the railway from Port Dalhousie to St. Catharines (1 page, handwritten), Jan. 11, 1855.

Approximate estimate of the cost of extending the Port Dalhousie and Thorold Railway from Geneva Street to the Great Western Railway Station at Lock no. 12

Approximate estimate of the cost of extending the Port Dalhousie and Thorold Railway from Geneva Street to the Great Western Railway Station at Lock no. 12 (2 copies) [one appears to be a rough copy] (2 pages, handwritten), Feb. 2, 1855.

Letter of estimate sent to S.D. Woodruff for the total cost of construction and equipment of the extension of the line to Port Colborne

Letter of estimate sent to S.D. Woodruff for the total cost of construction and equipment of the extension of the line to Port Colborne [this is unsigned]. There is an envelope with this letter that suggests that it is from Mr. Shanly, Mar. 12, 1857.

Chart of estimate of cost of Port Dalhousie and Thorold Railway extension Line no. 1

Chart of estimate of cost of Port Dalhousie and Thorold Railway extension Line no. 1 signed by Mr. Shanly, Mar. 12, 1857.

Chart of the estimated cost of Line no. 1

Chart of the estimated cost of Line no. 1, n.d.

Chart outlining Port Dalhousie and Thorold Railway cost of planks, bridge, railway crossing and approaches thereto

Chart outlining Port Dalhousie and Thorold Railway cost of planks, bridge, railway crossing and approaches thereto, n.d.

Approximate estimate of the cost of macadamizing, grading, bridging and putting in culverts from Hurst’s Bridge above Thorold to Port Robinson

Approximate estimate of the cost of macadamizing, grading, bridging and putting in culverts from Hurst’s Bridge above Thorold to Port Robinson (2 pages, handwritten), n.d.

List of abstracts (2 pages, handwritten) stating the cost of S.D. Woodruff dwelling and barns

List of abstracts (2 pages, handwritten) stating the cost of S.D. Woodruff dwelling and barns, January, 1878.

Electrocortical indices of cognitive control in working memory : exploring the effects of proactive interference, cognitive load, and aging

Cognitive control involves the ability to flexibly adjust cognitive processing in order to resist interference and promote goal-directed behaviour. Although frontal cortex is considered to be broadly involved in cognitive control, the mechanisms by which frontal brain areas implement control functions are unclear. Furthermore, aging is associated with reductions in the ability to implement control functions and questions remain as to whether unique cortical responses serve a compensatory role in maintaining maximal performance in later years. Described here are three studies in which electrophysiological data were recorded while participants performed modified versions of the standard Sternberg task. The goal was to determine how top-down control is implemented in younger adults and altered in aging. In study I, the effects of frequent stimulus repetition on the interference-related N450 were investigated in a Sternberg task with a small stimulus set (requiring extensive stimulus resampling) and a task with a large stimulus set (requiring no stimulus resampling).The data indicated that constant stimulus res amp ling required by employing small stimulus sets can undercut the effect of proactive interference on the N450. In study 2, younger and older adults were tested in a standard version of the Sternberg task to determine whether the unique frontal positivity, previously shown to predict memory impairment in older adults during a proactive interference task, would be associated with the improved performance when memory recognition could be aided by unambiguous stimulus familiarity. Here, results indicated that the frontal positivity was associated with poorer memory performance, replicating the effect observed in a more cognitively demanding task, and showing that stimulus familiarity does not mediate compensatory cortical activations in older adults. Although the frontal positivity could be interpreted to reflect maladaptive cortical activation, it may also reflect attempts at compensation that fail to fully ameliorate agerelated decline. Furthermore, the frontal positivity may be the result of older adults' reliance on late occurring, controlled processing in contrast to younger adults' ability to identify stimuli at very early stages of processing. In the final study, working memory load was manipulated in the proactive interference Sternberg task in order to investigate whether the N450 reflects simple interference detection, with little need for cognitive resources, or an active conflict resolution mechanism that requires executive resources to implement. Independent component analysis was used to isolate the effect of interference revealing that the canonical N450 was based on two dissociable cognitive control mechanisms: a left frontal negativity that reflects active interference resolution, , but requires executive resources to implement, and a right frontal negativity that reflects global response inhibition that can be relied on when executive resources are minimal but at the cost of a slowed response. Collectively, these studies advance understanding of the factors that influence younger and older adults' ability to satisfy goal-directed behavioural requirements in the face of interference and the effects of age-related cognitive decline.