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Edmonton, Canada

Overend A.,MacEwan University
Food, Culture and Society | Year: 2013

Discourses of nutritional health are strongly associated with illness, and have recently been linked to the prevalence and management of chronic undefined disorders. Using the case of Candida-a yeast-related disorder of vague symptomatology-I explore the role of food in the narratives of twenty-four people living with Candida. As Candida remains a speculative illness within the boundaries of biomedical science, it is relevant to critically explore the often-focal role of food in the management of this condition, and to consider the range of personal, social and cultural motivations at work in its dietary regulation. Taking up Foucault's theory of docility, I trace the ways in which dietary practices can be understood as normalizing the Candidad-body by helping to create a sense of certainty and control in the persistent face of illness ambiguity. In drawing on Foucault's later work, I move beyond illness dieting as solely a disciplinary regime and explore the ways in which dietary regime can also be conceptualized as a practice in the care of the self, fostering a heightened, often-changing sense of self. While Candida dieting practices will never fully operate separate from the pervasive discourses of nutritional science, they can offer productive possibilities in the regulation and maintenance of an illness not fully recognized by biomedical science. © Association for the Study of Food and Society 2013.

Walton E.L.,MacEwan University | Walton E.L.,University of Alberta | Sharp T.G.,Arizona State University | Hu J.,Arizona State University | Filiberto J.,Southern Illinois University Carbondale
Geochimica et Cosmochimica Acta | Year: 2014

The microtexture and mineralogy of shock melts in the Tissint martian meteorite were investigated using scanning electron microscopy, Raman spectroscopy, transmission electron microscopy and synchrotron micro X-ray diffraction to understand shock conditions and duration. Distinct mineral assemblages occur within and adjacent to the shock melts as a function of the thickness and hence cooling history. The matrix of thin veins and pockets of shock melt consists of clinopyroxene. +. ringwoodite. ±. stishovite embedded in glass with minor Fe-sulfide. The margins of host rock olivine in contact with the melt, as well as entrained olivine fragments, are now amorphosed silicate perovskite. +. magnesiowüstite or clinopyroxene. +. magnesiowüstite. The pressure stabilities of these mineral assemblages are ~15. GPa and >19. GPa, respectively. The ~200-μm-wide margin of a thicker, mm-size (up to 1.4. mm) shock melt vein contains clinopyroxene. +. olivine, with central regions comprising glass. +. vesicles. +. Fe-sulfide spheres. Fragments of host rock within the melt are polycrystalline olivine (after olivine) and tissintite. +. glass (after plagioclase). From these mineral assemblages the crystallization pressure at the vein edge was as high as 14. GPa. The interior crystallized at ambient pressure. The shock melts in Tissint quench-crystallized during and after release from the peak shock pressure; crystallization pressures and those determined from olivine dissociation therefore represent the minimum shock loading. Shock deformation in host rock minerals and complete transformation of plagioclase to maskelynite suggest the peak shock pressure experienced by Tissint. ≥. 29-30. GPa. These pressure estimates support our assessment that the peak shock pressure in Tissint was significantly higher than the minimum 19. GPa required to transform olivine to silicate perovskite plus magnesiowüstite.Small volumes of shock melt (<100μm) quench rapidly (0.01s), whereas thermal equilibration will occur within 1.2s in larger volumes of melt (1mm2). The apparent variation in shock pressure recorded by variable mineral assemblages within and around shock melts in Tissint is consistent with a shock pulse on the order of 10-20ms combined with a longer duration of post-shock cooling and complex thermal history. This implies that the impact on Mars that shocked and ejected Tissint at ~1Ma was not exceptionally large. © 2014 Elsevier Ltd.

Jung S.,MacEwan University
International Journal of Law and Psychiatry | Year: 2015

High levels of insight are interpreted as indications of a treatment compliance and good outcome by clinical professionals. However, it is unclear whether a defendant's insight plays a role in the decision-making of jurors when determining criminal responsibility. It may be the case that personal biases and attitudes toward the mentally ill and the insanity defense are more relevant in such decisions. This study examines the influence of two core dimensions of insight and personal attitudes on juror decision-making. Participants read trial scenarios describing a defendant who is accused of a violent crime and is diagnosed with schizophrenia. Assigning a verdict of not criminally responsible to the defendant was not influenced by insight, but instead, by supportive attitudes of the insanity defense and higher attributions of blame to external factors and to psychological factors. These findings highlight the need for continued investigation in the area of extra-legal factors that guide legal decision-making when defendants have a mental disorder. © 2015 Elsevier Ltd.

Walton E.L.,MacEwan University | Walton E.L.,University of Alberta
Geochimica et Cosmochimica Acta | Year: 2013

Lithology A of Martian meteorite Elephant Moraine (EET) A79001 contains fragments entrained within a 100μm-thick shear-induced shock vein. These fragments, the shock vein matrix and walls of olivine along the vein, as well as shock deformation and transformation in rock-forming minerals in the bulk rock, were investigated using scanning electron microscopy, the electron microprobe and Raman spectroscopy. The presence of ringwoodite, the spinel-structured high-pressure (Mg,Fe)2SiO4 polymorph, has been confirmed in EETA79001 for the first time. Ringwoodite occurs within and around the shock vein, exhibiting granular and lamellar textures. In both textures ringwoodite consists of ∼500nm size distinct grains. Ringwoodite lamellae are 115nm to 1.3μm wide. Planar fractures in olivine provided sites for heterogeneous nucleation of ringwoodite. Analyses performed on the largest grains (≥1μm) show that ringwoodite is consistently higher in iron (Fa27.4-32.4) relative to surrounding olivine (Fa25.1-267.7), implying that there was Fe-Mg exchange during their transformation, and therefore their growth was diffusion-controlled. In the shock environment, diffusion takes place dynamically, i.e., with concurrent deformation and grain size reduction. This results in enhanced diffusion rates (≥10-8m2/s) over nm - μm distances.Shock deformation in host rock minerals including strong mosaicism, pervasive fracturing, polysynthetic twinning (pyroxene only), extensive shock melting, local transformation of olivine to ringwoodite, and complete transformation of plagioclase to maskelynite in the bulk rock, indicate that EETA79001 was strongly shocked. The short shock duration (0.01. s) combined with a complex thermal history, resulted in crystallization of the 100 μm thick shock vein in EETA79001 during the pressure release, and partial back-transformation of ringwoodite to olivine. Based on the pressure stabilities of clinopyroxene. +. ringwoodite, crystallization at the shock vein margin began at ∼18. GPa. Olivine and clinopyroxene crystallized at <14. GPa closer to the shock vein center. These represent a minimum limit to the shock pressure loading experienced by EETA79001. © 2013 Elsevier Ltd.

Shaw C.S.J.,University of New Brunswick | Walton E.,MacEwan University | Walton E.,University of Alberta
Meteoritics and Planetary Science | Year: 2013

The distribution of shock melts in four shergottites, having both vein and pocket geometry, has been defined and the conductive cooling time over the range 2500°C to 900°C calculated. Isolated 1mm2 pockets cool in 1.17s and cooling times increase with pocket area. An isolated vein 1×7mm in Northwest Africa (NWA) 4797 cools to 900°C in 4.5s. Interference between thermal haloes of closely spaced shock melts decreases the thermal gradient, extending cooling times by a factor of 1.4 to 100. This is long enough to allow differential diffusion of Ar and Xe from the melt. Small pockets (1mm2) lose 2.2% Ar and 5.2% Xe during cooling, resulting in a small change in the Ar/Xe ratio of the dissolved gas over that originally trapped. With longer cooling times there is significant fractionation of Xe from Ar and the Ar/Xe ratio increases rapidly. The largest pockets show less variation of Ar/Xe and likely preserve the original trapped gas composition. Considering all of the model calculations, even the smallest isolated pockets have cooling times greater than the duration of the pressure pulse, i.e., >0.01s. The crystallization products of these shock melts will be unrelated to the peak shock pressure experienced by the meteorite. © The Meteoritical Society, 2013.

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