University of Winnipeg

About: University of Winnipeg is a education organization based out in Winnipeg, Manitoba, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 3235 authors who have published 6413 publications receiving 150564 citations. The organization is also known as: U of W.

The semicircular canal system and locomotion: The case of extinct lemuroids and lorisoids

Abstract: Paleontologists reconstruct the locomotor and postural behavior of extinct species by analogy with living forms and biomechanical analyses. In rare cases, behavioral evidence such as footprints can be used to confirm fossil-based reconstructions for predominantly terrestrial orders of mammals. For instance, the chalicothere prints from Laetoli show that these perissodactyls supported their body weight on the metacarpals, as previously reconstructed.1. Unfortunately, primates are mostly arboreal and rarely leave footprints. The cercopithecid and hominin prints at Laetoli are a rare exception. We have recently shown that the semicircular canal system can be used to test and augment locomotor reconstructions based on postcranial material or to provide first estimations of locomotor behavior for taxa not known from the postcranium. Using a sample of modern primates, we have been able to demonstrate that the radii of curvature of the semicircular canals are significantly correlated with both body mass and agility of locomotion.2 This paper reviews those results and examines the relationship between semicircular canal morphology and other evidence in efforts to reconstruct locomotor behavior in subfossil lemurs from the Holocene of Madagascar and fossil lorisoids from the Miocene of Africa. © 2008 Wiley-Liss, Inc.

Photocatalytic Degradation of 1,10-Dichlorodecane in Aqueous Suspensions of TiO2: A Reaction of Adsorbed Chlorinated Alkane with Surface Hydroxyl Radicals

Abstract: 1,10-Dichlorodecane (D2C10) is shown to be effectively photodegraded in aqueous suspensions of TiO2 using a photoreactor equipped with 300 nm lamps. Solutions exposed to UV light intensities of 3.6 × 10-5 Ein L-1 min-1, established by ferrioxalate actinometry, showed negligible direct photolysis in the absence of TiO2. The degradation rate was optimal with 150 mg/L of TiO2 and a D2C10 concentration (240 μg/L) approaching its solubility limit. Kinetics of photodegradation followed a Langmuir−Hinshelwood model suggesting that the reaction occurred on the surface of the photocatalyst. The presence of h+vb and OH• radical scavengers, including methanol and iodide, inhibited the degradation supporting a photooxidation reaction. Electron scavengers (Ag+, Cu2+, and Fe3+) had small effects on the degradation rate. The lack of transformation of D2C10 in acetonitrile as solvent indicated that the major oxidants were OH• radicals. The presence of tetranitromethane, effectively eliminating the formation of free OH• r...

Credence Goods, Efficient Labelling Policies, and Regulatory Enforcement

Abstract: We analyse the optimality of information revelation of hidden attributes of “credence goods” via alternative labelling procedures. When consumers are heterogeneous in their willingness to pay for the hidden attribute, producers can either self-label their products, or have them certified by a third party. The government can impose self or third party labelling requirements on either the “green” or the “brown” producers. Our benchmark model develops a condition that links the optimal imposition of third party labelling to the relative market share of each type of the good under complete information. We extend our analysis to incorporate asymmetric information and cheating by the producers. When corrupt producers can affix spurious labels, the government needs to supplement the labelling policy with costly monitoring activities. We find that mandatory self-labelling schemes generally dominate mandatory third party labelling, unless the “market share effect” greatly exceeds the “incentive-to-cheat effect”.