The Influence of Cerebral Blood Flow and Carbon Dioxide on Neuromuscular Responses During Environmental Stress

Although reductions in cerebral blood flow (CBF) may be implicated in the development of central fatigue during environmental stress, the contribution from hypocapnia-induced reductions in CBF versus reductions in CBF per se has yet to be isolated. The current research program examined the influence of CBF, with and without consequent hypocapnia, on neuromuscular responses during hypoxia and passive heat stress. To this end, neuromuscular responses, as indicated by motor evoked potentials (MEP), maximal M-wave (Mmax) and cortical voluntary activation (cVA) of the flexor carpi radialis muscle during isometric wrist flexion, was assessed in three separate projects: 1) hypocapnia, independent of concomitant reductions in CBF; 2) altered CBF during severe hypoxia and; 3) thermal hyperpnea-mediated reductions in CBF, independent of hypocapnia. All projects employed a custom-built dynamic end-tidal forcing system to control end-tidal PCO2 (PETCO2), independent of the prevailing environmental conditions, and cyclooxygenase inhibition using indomethacin (Indomethacin, 1.2 mg·Kg-1) to selectively reduce CBF (estimated using transcranial Doppler ultrasound) without changes in PETCO2. A primary finding of the present research program is that the excitability of the corticospinal tract is inherently sensitive to changes in PaCO2, as demonstrated by a 12% increase in MEP amplitude in response to moderate hypocapnia. Conversely, CBF mediated reductions in cerebral O2 delivery appear to decrease corticospinal excitability, as indicated by a 51-64% and 4% decrease in MEP amplitude in response to hypoxia and passive heat stress, respectively. The collective evidence from this research program suggests that impaired voluntary activation is associated with reductions in CBF; however, it must be noted that changes in cVA were not linearly correlated with changes in CBF. Therefore, other factors independent of CBF, such as increased perception of effort, distress or discomfort, may have contributed to the reductions in cVA. Despite the functional association between reductions in CBF and hypocapnia, both variables have distinct and independent influence on the neuromuscular system. Therefore, future studies should control or acknowledge the separate mechanistic influence of these two factors.

Estimate of road price from Port Robinson to Beaverdams Road

Estimate of road price from Port Robinson to Beaverdams Road, n.d.

Letter to P.I. Price asking him to make out a cheque in favour of German and Pettit for looking after certain petitions in Willoughby and Bertie Townships and in Welland

Letter to P.I. Price asking him to make out a cheque in favour of German and Pettit for looking after certain petitions in Willoughby and Bertie Townships and in Welland. This is signed by H.H. Collier, March 5, 1906.

Letter to Mr. Price from E.J. McIntryre regarding a cheque for the assessment on a railway

Letter to Mr. Price from E.J. McIntryre regarding a cheque for the assessment on a railway, Dec. 25, 1910.

Letter to Mr. W.D. Woodruff of Lincoln Paper Mills, Merritton from P.J. Price of the United Gas Companies

Letter to Mr. W.D. Woodruff of Lincoln Paper Mills, Merritton from P.J. Price of the United Gas Companies, St. Catharines regarding a cheque received from E.J. McIntyre for $200. Included with this letter is an envelope addressed to W.D. Woodruff, Dec. 27, 1910.

Receipt from Collier and Burson, Barristers and Solicitors, St. Catharines to P. J. Price

Receipt from Collier and Burson, Barristers and Solicitors, St. Catharines to P. J. Price on account of railway legislation, Jan. 27, 1906.

Probate (vellum) of Last Will and Testament of Hervey William Price of Welland who died Jan. 27, 1875

Probate (vellum) of Last Will and Testament of Hervey William Price of Welland who died Jan. 27, 1875. It is proven that the administration of the estate was granted to Joseph Augustus Woodruff, Aug. 19, 1880.

Formación de enlaces dobles carbon-carbon promovidos con R3P y metales electropositivos

Tesis (Maestría en Ciencias con Especialidad en Química Orgánica) UANL

Influence of functional groups of activated carbon in the anchoring of iron particles by forced hydrolysis and its use to remove hexavalent chromiun from aqueous solutions.

Tesis (Master of Science with orientation in Sustainable Processes) UANL, 2014.

The Wage Rate and the Profit Rate in the Price of Production Equation: a New Solution to an Old Problem

The aim of this paper is to demonstrate that, even if Marx's solution to the transformation problem can be modified, his basic concusions remain valid.

Inter-temporal Price Discrimination when Imports are Restricted by Quotas

A dominant firm holding import quota engages in inter-temporal price discrimination when facing a competitive fringe engaged in seasonal production. This causes a welfare loss that comes in addition the loss attributable to limitation of imports below the free trade level.

The Backing of Government Debt and the Price Level

This paper studies the interdependence between fiscal and monetary policies, and their joint role in the determination of the price level. The government is characterized by a long-run fiscal policy rule whereby a given fraction of the outstanding debt, say d, is backed by the present discounted value of current and future primary surpluses. The remaining debt is backed by seigniorage revenue. The parameter d characterizes the interdependence between fiscal and monetary authorities. It is shown that in a standard monetary economy, this policy rule implies that the price level depends not only on the money stock, but also on the proportion of debt that is backed with money. Empirical estimates of d are obtained for OECD countries using data on nominal consumption, monetary base, and debt. Results indicate that debt plays only a minor role in the determination of the price level in these economies. Estimates of d correlate well with institutional measures of central bank independence.

ITEM : An Integrated Transport Economy Model - Price Elasticities of Freight Transport Demand in Canada : Three Canadian Markets and Four Commodities.

Rapport de recherche

Parametric and Nonparametric Approaches to Price and Tax Reform.

In the analysis of tax reform, when equity is traded off against efficiency, the measurement of the latter requires us to know how tax-induced price changes affect quantities supplied and demanded. in this paper, we present various econometric procedures for estimating how taxes affect demand.