Abstract. Cloud computing is receiving increasingly attention as it provides infinite resource capacity and "pay-as-you-go" resource usage pattern to hosted applications. To maintain its SLA targets, resource provisioning of service-oriented applications in the cloud requires reliable performance from the cloud resources. In this paper, we study performance behavior of small instances in Amazon EC2. We demonstrate that the performance of virtual instances is relatively stable over time with fluctuations of mean response time within at most 8% of the long-term average. Moreover, we also show that different supposedly identical instances often have very different performance, up to a ratio 4 from each other. We consider this as an important issue that must be addressed, but also as an opportunity as it allows one to assign each instance with a task that matches its own performance profile.

Invasive growth of cancer cells is a complex process involving specific interactions between tumour cells and the orderly, integrated complexes of the extracellular matrix. Basement membranes have been proposed as one constituent of extracellular matrix which carries responsibility for regulating invasion and metastasis. Using a chemically induced rat tongue carcinoma model, it has been shown that components of the basement membrane and its overall structure are altered during tumour invasion, and methods have been developed to quantitate some of these differences. Since the basement membrane can be specifically characterized by its fibrous protein network of Type IV collagen and laminin, which is embedded in a heparan sulphate-rich proteoglycan matrix, these components have been targeted. In particular, the current paper presents results in the context of current concepts of early changes in neoplastic invasion of underlying connective tissues. In consequence, further elaboration of the underlying mechanisms of epithelial migration in oral cancer may allow an exploration of the use of alterations in expression of basement membrane components as prognostic indicators.

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The habit of reverse smoking is practised in various parts of the world including the Philippines. In this pilot, community-based, cross-sectional study carried out in the region of Cabanatuan City in the Philippines. 61 Filipina reverse smokers and 30 Filipina conventional smokers were interviewed and clinically examined. Seven demographic variables and twelve habit variables were compared in the two study groups. The majority (96.7 per cent) of reverse smokers exhibited palatal mucosal changes including leukoplakia, mucosal thickening, fissuring, pigmentation, nodularity, erythema and ulceration. In comparison, only 26.7 per cent of conventional smokers exhibited mucosal changes predominantly focal pigmentation and mild erythema. This difference was statistically significant at a X2 value of 47.28 (p < .001). Analysis of the other variables indicated that the two study groups differed significantly with regard to age (p < .05), educational attainment (p < .01), use of filtered versus non-filtered cigarettes (p < .001) and duration of smoking in years (p < .01).