Ontario Ministry of Transportation

About: Ontario Ministry of Transportation is a government organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Poison control & Asphalt. The organization has 4652 authors who have published 3882 publications receiving 59011 citations.

Transfer of microcontaminants from sediment to chironomids, and the risk for the Pond bat Myotis dasycneme (Chiroptera) preying on them

Abstract: Transfer ratios of metals, PCBs, pesticides and PAHs from the sediment to chironomid larvae and adults collected in a highly contaminated area, the Biesbosch, were studied Metal concentrations in larvae were 028 (Cd), 002 (Cr), 052 (Cu), 006 (Hg), 003 (Pb), 032 (Zn) times those found in standard sediment, on a dry weight basis Hg and Zn were well transported to the adult stage Dry weight ratios of contaminant residues in adults and in larvae were 038 (Cd), 023 (Cr), 062 (Cu), 103 (Hg), 008 (Pb), 094 (Zn) For PCBs and pesticides, the concentration ratios of chironomid larvae fat to sediment (dry organic matter) varied around 33, which is consistent with laboratory studies Organochlorine residues in adult fat were comparable to those in larvae lipids However, the concentrations of non-ortho PCBs were 17 times higher in adults For polycyclic aromatic hydrocarbons (PAH), larval fat:sediment (organic matter) concentration ratios ranged from 0004 to 01 Adult: larvae ratios for PAHs varied between 02 and 06 For naphthalene a much higher transport ratio of 2 was found Chironomid adults are the most important potential food source of the Pond bat, which lives in low densities in the Biesbosch The contaminant concentrations measured in the chironomids do not exceed diet levels that are thought to be safe for mammals However, Pond bats collected in less contaminated areas contained PCB-concentrations of 9, 33 and 76 mg kg−1 lipid weight, which are above concentrations that cause reproduction effects on Mink

Rigid pavement performance models by means of Markov Chains with half-year step time

Abstract: Pavement management systems employ pavement performance models to plan the most effective allocation of public funds. The most used models are the deterministic and the probabilistic or stochastic ones. Among stochastic models, the Markov Chains are receiving considerable research attention. In this paper, transition probability matrices (TPMs) are presented for Portland Cement Concrete (PCC) pavement road network in the Republic of Moldova with available International Roughness Index (IRI) data collected in spring and in autumn from 2013 to 2015. Although one-year cycle time is usually employed, half-year cycle time was defined to handle a bigger amount of transitions. The aim of this paper is to prove that TPMs for rigid pavements can be developed using IRI values from a short period, with a half-year step time, for a road network where the time since last major rehabilitation varies in each section and where maintenance and rehabilitation activities are carried out simultaneously. In order to c...