2 resultados para time of application and nutrient leaf content
em WestminsterResearch - UK
Resumo:
The cortisol awakening response (CAR) is typically measured in the domestic setting. Moderate sample timing inaccuracy has been shown to result in erroneous CAR estimates and such inaccuracy has been shown partially to explain inconsistency in the CAR literature. The need for more reliable measurement of the CAR has recently been highlighted in expert consensus guidelines where it was pointed out that less than 6% of published studies provided electronic-monitoring of saliva sampling time in the post-awakening period. Analyses of a merged data-set of published studies from our laboratory are presented. To qualify for selection, both time of awakening and collection of the first sample must have been verified by electronic-monitoring and sampling commenced within 15 min of awakening. Participants (n = 128) were young (median age of 20 years) and healthy. Cortisol values were determined in the 45 min post-awakening period on 215 sampling days. On 127 days, delay between verified awakening and collection of the first sample was less than 3 min (‘no delay’ group); on 45 days there was a delay of 4–6 min (‘short delay’ group); on 43 days the delay was 7–15 min (‘moderate delay’ group). Cortisol values for verified sampling times accurately mapped on to the typical post-awakening cortisol growth curve, regardless of whether sampling deviated from desired protocol timings. This provides support for incorporating rather than excluding delayed data (up to 15 min) in CAR analyses. For this population the fitted cortisol growth curve equation predicted a mean cortisol awakening level of 6 nmols/l (±1 for 95% CI) and a mean CAR rise of 6 nmols/l (±2 for 95% CI). We also modelled the relationship between real delay and CAR magnitude, when the CAR is calculated erroneously by incorrectly assuming adherence to protocol time. Findings supported a curvilinear hypothesis in relation to effects of sample delay on the CAR. Short delays of 4–6 min between awakening and commencement of saliva sampling resulted an overestimated CAR. Moderate delays of 7–15 min were associated with an underestimated CAR. Findings emphasize the need to employ electronic-monitoring of sampling accuracy when measuring the CAR in the domestic setting.
Resumo:
This thesis explores changing discourses of childhood and the ways in which power relations intersect with socio-cultural norms to shape screen-based media for Palestinian children. Situated within the interdisciplinary study of childhood, the research is an institutional and textual analysis that includes discursive and micro-level analysis of the socio-political circumstances within which children consume media in present-day Palestine. The thesis takes a social constructionist view, arguing that ‘childhood’ is not a fixed universal concept and that discourses of childhood are produced at specific historical moments as an effect of power. The study has a three-part research agenda. The first section uses secondary literature to explore theories and philosophies relating to definitions of childhood in Arab societies. The second employs participant observation and semi-structured interviews to understand the history and politics of children’s media in the West Bank. The final part of the research activity focuses on the impact that definitions of childhood and the politics of children’s media have on broadcasting outcomes through an analysis of (a) discourses on children’s media that circulate in Palestinian society, and (b) local and pan-Arab cultural texts consumed by Palestinian children. The analysis demonstrates that complex ideological and political factors are at play, which has led to the marginalisation, politicisation and internationalisation of local production for children. Due to the lack of alternatives, local producers often rely on international funding, and are hence forced to negotiate competing definitions of childhood, which while fitting with an international agenda of normalising the Israeli occupation, conflict culturally and politically with local conceptions of childhood and hopes for the Palestinian nation. While the Palestinian community appreciates the positive potential of local production, discourses and strategies around children’s media show that Palestinian children are constructed as vulnerable, incomplete and in constant need of guidance. Pan-Arab content presents a slightly less didactic approach and in certain cases presents childhood as a dynamic space of empowerment. However, by constructing children as ‘consumercitizens’, it alienates Arab (and Palestinian) children from disadvantaged backgrounds,as the preferred audience is middle-class children living in oil-rich countries of the Gulf.