6 resultados para essential mineral

em Brock University, Canada


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Non-governmental organizations and transnational networks have been increasingly successful a t gaining influence within issue areas traditionally controlled by the state. In many instances, non-state actors have been instrumental in forcing issues onto the global agenda, have aided in the development or transformation of global regimes, and have participated in securing state compliance for the adoption of new international norms. This paper argues that, consistent with social constructivist theory, ideas are important in influencing state preferences and change may be possible when certain factors are present. I f non-state actors can influence states, it is meaningful to understand how this happens. This paper focuses on a campaign led by Medecins Sans Frontieres that began in the late 1990s to acquire affordable medicines for patients in developing states that could not afford patented drugs. The campaign reached a measure of success in that member states of the World Trade Organization re-negotiated contested terms and meanings within the trade agreement for intellectual property rights and allowed concessions that would benefit lower income states. What factors contributed to the success of the campaign? And what were the most important factors - the issue, the actors or the mechanisms used?

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An instrumental case study was conducted to explore the perspective of recent graduates from a Greater Toronto Area community college experience in relation to Workplace Essential Skills (WES). Five participants who graduated from a business school within the last 4 years were interviewed twice over a 4-month period to gain a deeper understanding of this relationship. This qualitative approach used semi-structured interviews to elicit stories about their experiences, their relationships in school, and the development of skills that were useful in the workplace. The analysis of data involved the 3-step coding process of open, axial, and selective coding consistent with the approach used by Neuman (2006). The analysis revealed that the overall experience of attending college contributed to the learning that took place. The participants gave greater significance to the life experience in learning WES and the networks associated with learning than the formal aspects of education. It is also important to acknowledge that the research identified a significant opportunity for educators’ to positively impact the learning experience.

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High chromium content in kimberlite indicator minerals such as pyrope garnet and diopside is often correlated with the presence of diamonds. In this study, kimberlite indicator minerals were examined using visible light reflectance spectroscopy to determine if chromium content can be correlated with spectral absorption features. The depth of absorption features in the visible spectral region were correlated with the molecular percentage of chromium and other first series transition metal elements obtained by electron microprobe data. In the visible part of the spectrum, chromium is evident by 3 absorption features in the pyrope reflectance spectrum; one isolated and narrow feature at the wavelength 689 nm was used to correlate with the chromium mol %. The isolation of this feature in the pyrope spectra is advantageous since it is not directly affected by other proximal absorption bands that could be caused by other transition metals. Analysis of the feature indicates that as grain volume increases the depth of the absorption feature will also increase. Clustering grain volumes into fractions yields better correlation between absorption depth and mol % chromium. Other types of garnet (almandine, grossular, spessartine) and kimberlite indicator minerals (olivine, diopside, chromite, ilmenite) were analyzed to determine if other absorption features could be used to predict the proportion of specific transition metal elements. Diopside in particular illustrates the same isolated chromium absorption feature as pyrope and may indicate mol percent but needs further study with larger sample sets.

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Remote sensing techniques involving hyperspectral imagery have applications in a number of sciences that study some aspects of the surface of the planet. The analysis of hyperspectral images is complex because of the large amount of information involved and the noise within that data. Investigating images with regard to identify minerals, rocks, vegetation and other materials is an application of hyperspectral remote sensing in the earth sciences. This thesis evaluates the performance of two classification and clustering techniques on hyperspectral images for mineral identification. Support Vector Machines (SVM) and Self-Organizing Maps (SOM) are applied as classification and clustering techniques, respectively. Principal Component Analysis (PCA) is used to prepare the data to be analyzed. The purpose of using PCA is to reduce the amount of data that needs to be processed by identifying the most important components within the data. A well-studied dataset from Cuprite, Nevada and a dataset of more complex data from Baffin Island were used to assess the performance of these techniques. The main goal of this research study is to evaluate the advantage of training a classifier based on a small amount of data compared to an unsupervised method. Determining the effect of feature extraction on the accuracy of the clustering and classification method is another goal of this research. This thesis concludes that using PCA increases the learning accuracy, and especially so in classification. SVM classifies Cuprite data with a high precision and the SOM challenges SVM on datasets with high level of noise (like Baffin Island).

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Some cross-sectional and prospective studies have demonstrated a positive correlation between habitual tea consumption and bone mineral density in post-menopausal women. Rooibos tea contains no caffeine and is a rich source of flavonoids such as rutin, orientin, hyperoside and luteolin. These flavonoids have similar structures to estradiol, and therefore may act as estrogen mimics to promote favourable outcomes in bone. The overall objective of this research was to identify flavonoids that could enhance mineral content in human osteoblast Saos2 cells. Mineral was quantified by alizarin red staining and characterized by quantifying alkaline phosphatase (ALP) activity, cell mitochondria activity and toxicity, in addition to changes in regulatory markers of osteoblastic activity. Rutin (≥50μM), hyperoside (≥5.0μM), orientin (0.1μM-1.0μM, 15μM-100μM) and luteolin (5.0μM) enhanced mineral content. This was in part due to elevated ALP and mitochondrial activity, and lower toxicity, pro-inflammatory cytokines, and Wnt inhibitors.

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The ovariectomized (OVX) rat, a preclinical model for studying postmenopausal bone loss, may also be used to study differences in alveolar bone (AB). The objectives of this study were to quantify the differences in AB following estrogen replacement therapy (ERT), and to investigate the relationship between AB structure and density, and trabecular bone at the femoral neck (FN) and third lumbar vertebral body (LB3). Estrogen treated rats had a higher bone volume fraction (BV/TV) at the AB region (9.8% P < 0.0001), FN (12% P < 0.0001), and LB3 (11.5% P < 0.0001) compared to the OVX group. BV/TV of the AB was positively correlated with the BV/TV at the FN (r = 0.69 P < 0.0001) and the LB3 (r = 0.75 P < 0.0001). The trabecular number (Tb.N), trabecular separation (Tb.Sp), and structure model index (SMI) were also positively correlated (P < 0.05) between the AB and FN (r = 0.42, 0.49, and 0.73, respectfully) and between the AB and LB3 (r = 0.44, 0.63, and 0.69, respectfully). Given the capacity of AB to respond to ERT, future preclinical drug/nutritional intervention studies aimed at improving skeletal health should include the AB as a region of interest (ROI).