2 resultados para transition to turbulence

em Greenwich Academic Literature Archive - UK


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Research on disadvantaged young fathers has been minimally addressed in the literature, particularly in the UK. In both countries teenage pregnancy rates are high and costly in terms of social policy and community provision. This paper explores 2 studies involving 24 young men with an average age of 17 on the transition to young fatherhood; one study was conducted in the UK with white young men and the other in the USA with black young men. The findings from both studies indicated common themes from their stories, particularly with regard to the high levels of disadvantage and social exclusion they had been exposed to in their demographic environments and the anti-social behaviour they described engaging in, prior to the birth of their child/ren. Specifically, a significant proportion of the young men described how they had been immersed in drug and gun crimes and how this shaped their lives and neighbourhoods. Becoming fathers is presented by both sets of young men as rescuing them from this criminal lifestyle.

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This paper studies the possibility of distinguishing between benign and malignant masses by exploiting the morphology-dependent temporal and spectral characteristics of their microwave backscatter response in ultra-wideband breast cancer detection. The spiculated border profiles of 2-D breast masses are generated by modifying the baseline elliptical rings based upon the irregularity of their peripheries. Furthermore, the single- and multilayer lesion models are used to characterize a distinct mass region followed by a sharp transition to background, and a blurred mass border exhibiting a gradual transition to background, respectively. Subsequently, the complex natural resonances (CNRs) of the backscatter microwave signature can be derived from the late-time target response and reveal diagnostically useful information. The fractional sequence CLEAN algorithm is proposed to estimate the lesions' delay intervals and identify the late-time responses. Finally, it is shown through numerical examples that the locations of dominant CNRs are dependent on the lesion morphologies, where 2-D computational breast phantoms with single and multiple lesions are investigated. The analysis is of potential use for discrimination between benign and malignant lesions, where the former usually possesses a better-defined, more compact shape as opposed to the latter.