University of Windsor

About: University of Windsor is a education organization based out in Windsor, Ontario, Canada. It is known for research contribution in the topics: Population & Argumentation theory. The organization has 10654 authors who have published 22307 publications receiving 435906 citations. The organization is also known as: UWindsor & Assumption University of Windsor.

The genesis of hydrothermal fluorite-REE deposits in the Gallinas Mountains, New Mexico

Abstract: Breccia-hosted fluorite-bastnaesite deposits associated with epizonal quartz syenite intrusions in the Gallinas Mountains, New Mexico, provide an important example of hydrothermal rare earth element (REE) mineralization, and an excellent opportunity to investigate the transport and deposition of the REE under hydrothermal conditions. Fluid inclusion studies show that mineralization commenced with the deposition of quartz at a temperature of approximately 400°C from sulfate-rich NaCl-KCl brines having a salinity of ~15 wt percent NaCl equiv. These fluids are interpreted to have been of orthomagmatic origin. Fluorite and bastnaesite deposition occurred at slightly lower temperatures, and coincided with the introduction of separate CO2-bearing and sulfate-poor NaCl brines into the system. These fluids are considered to have been of external origin, the latter being a formation water that circulated in surrounding Permian sandstones and limestones. Evaluation of the available thermodynamic data on the aqueous speciation of REE, and the preliminary data on the chemistry of the fluids obtained in this study, suggest that the REE were dissolved primarily as fluoride complexes. A model is proposed in which the REE were transported by the orthomagmatic fluids, and deposited as bastnaesite owing to destabilization of REE-fluoride complexes. The latter occurred in response to the sharp reduction in F– activity that accompanied large-scale deposition of fluorite as a result of mixing of the orthomagmatic fluids and formation waters. This mixing also led to the deposition of anhydrite and barite owing to the interaction of externally introduced calcium and barium ions with orthomagmatic sulfate ions. The later stages in the evolution of the Gallinas Mountains hydrothermal system were marked by increased incursion of external fluids, and the alteration of bastnaesite to Ca bastnaesite and minor deposition of Ca bastnaesite and parisite owing to lowered F–/\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(CO_{3}^{2{\mbox{--}}}\) \end{document} ratios and/or increased Ca2+ activity. The study suggests that Ca-free, REE fluoride-bearing fluids are an important ingredient for REE mineralization, that mixing of such fluids with Ca-, carbonate-bearing fluids or interaction with carbonate rocks is a major control of REE-fluorocarbonate mineral deposition, and that the occurrence of fluorite could provide an important guide in the exploration for economic REE deposits.

Entry into Elite Sport: A Preliminary Investigation into the Transition Experiences of Rookie Athletes

Abstract: Athletes experience a number of transitions throughout their athletic career (Wylleman, Alfermann, & Lavallee, 2004). One pivotal transition that has received less attention in the literature is the transition into elite sport. The purpose of the present study was to examine the transitioning experience of young athletes entering elite sport. Using a phenomenological approach, rookie ice hockey players (N = 8, representing two different Major Junior ‘A’ teams) were asked about their experiences of entering into elite sport. Two primary themes emerged from the young athletes’ responses: on-ice issues associated with performance and off-ice issues relating to relationships and personal development. These findings offer preliminary evidence that young athletes encounter transitional challenges during the entry into elite sport. Further research is necessary to explore how the entry experience impacts young athletes’ athletic and psychosocial development and well-being.

The methane cycle in ferruginous Lake Matano.

Abstract: In Lake Matano, Indonesia, the world's largest known ferruginous basin, more than 50% of authigenic organic matter is degraded through methanogenesis, despite high abundances of Fe (hydr)oxides in the lake sediments. Biogenic CH₄ accumulates to high concentrations (up to 1.4 mmol L⁻¹) in the anoxic bottom waters, which contain a total of 7.4 × 10⁵ tons of CH₄. Profiles of dissolved inorganic carbon (ΣCO₂) and carbon isotopes (δ¹³C) show that CH₄ is oxidized in the vicinity of the persistent pycnocline and that some of this CH₄ is likely oxidized anaerobically. The dearth of NO₃⁻ and SO₄²⁻ in Lake Matano waters suggests that anaerobic methane oxidation may be coupled to the reduction of Fe (and/or Mn) (hydr)oxides. Thermodynamic considerations reveal that CH₄ oxidation coupled to Fe(III) or Mn(III/IV) reduction would yield sufficient free energy to support microbial growth at the substrate levels present in Lake Matano. Flux calculations imply that Fe and Mn must be recycled several times directly within the water column to balance the upward flux of CH₄. 16S gene cloning identified methanogens in the anoxic water column, and these methanogens belong to groups capable of both acetoclastic and hydrogenotrophic methanogenesis. We find that methane is important in C cycling, even in this very Fe-rich environment. Such Fe-rich environments are rare on Earth today, but they are analogous to conditions in the ferruginous oceans thought to prevail during much of the Archean Eon. By analogy, methanogens and methanotrophs could have formed an important part of the Archean Ocean ecosystem.

A genetic algorithm based approach for energy efficient routing in two-tiered sensor networks

Abstract: Higher power relay nodes can be used as cluster heads in two-tiered sensor networks to achieve improved network lifetime. The relay nodes may form a network among themselves to route data towards the base station. In this model, the lifetime of a network is determined mainly by the lifetimes of these relay nodes. An energy-aware communication strategy can greatly extend the lifetime of such networks. However, integer linear program (ILP) formulations for optimal, energy-aware routing quickly become computationally intractable and are not suitable for practical networks. In this paper, we have proposed an efficient solution, based on a genetic algorithm (GA), for scheduling the data gathering of relay nodes, which can significantly extend the lifetime of a relay node network. For smaller networks, where the global optimum can be determined, our GA based approach is always able to find the optimal solution. Furthermore, our algorithm can easily handle large networks, where it leads to significant improvements compared to traditional routing schemes.