Fluorescence and photodegradation of Xuan paper: The photostability of traditional Chinese handmade paper

Xuan paper is a type of Chinese handmade paper produced for traditional calligraphy and painting in China since the Tang Dynasty (618–907 AD), and is therefore an important cultural heritage material. In this study, the fluorescence and photochemical properties of Xuan paper were investigated. Xuan paper exhibits auto-fluorescence in the blue spectral range (450–500 nm) and UVA photolysis of the paper resulted in a substantial reduction in the blue fluorescence together with the formation of chromophores absorbing in the visible spectrum, resulting in photoyellowing of the paper. A more significant yellowing of paper was observed when irradiated in the dry state than under wet conditions. The associated photogeneration of hydrogen peroxide and superoxide from three types of Xuan paper samples during irradiation showed a correlation between the yields of reactive oxygen species and their relative yellowing rates. The results are interpreted in terms of sensitised photooxidation via a mechanism of electron transfer involving the fluorophores in their excited singlet states being responsible for the photodegradation of Xuan paper. SEM/EDS analyses were performed on the Xuan paper samples to investigate their morphological and elemental characteristics. Silica-containing fibres characteristic of a special rice straw that grows in siliceous soil were observed in all types of Xuan paper. Micron-sized calcium precipitates possibly formed from the “lime-steaming” manufacture process were shown to protect against the acidification of paper during accelerated thermal ageing.     

Politics,Paradoxes and Pragmatics of Happiness

European leaders and the popular media have shown a new-found interest in happiness as a socio-political value and goal. A growing body of research attempts to identify the conditions under which humans experience the highest levels of happiness, life-satisfaction or subjective well-being. This essay examines what makes a contemporary science and politics of happiness possible by taking a critical look at such efforts to define, measure and promote happiness, while seeking out a range of diverging, often paradoxical, cultural discourses of happiness. The essay covers the following themes: happiness is attainable; happiness is lost; happiness is obligatory; happiness is impossible; and, happiness is inauthentic. The essay critically examines political uses of the word happiness, disrupting received opinions about this contested term.     

Depression and Anxiety in the Postnatal Period: An Examination of Infants’ Home Language Environment,Vocalizations, and Expressive Language Abilities

This longitudinal study investigated the effects of maternal emotional health concerns, on infants’ home language environment, vocalization quantity, and expressive language skills. Mothers and their infants (at 6 and 12 months; 21 mothers with depression and or anxiety and 21 controls) provided day-long home-language recordings. Compared with controls, risk group recordings contained fewer mother–infant conversational turns and infant vocalizations, but daily number of adult word counts showed no group difference. Furthermore, conversational turns and infant vocalizations were stronger predictors of infants’ 18-month vocabulary size than depression and anxiety measures. However, anxiety levels moderated the effect of conversational turns on vocabulary size. These results suggest that variability in mothers’ emotional health influences infants’ language environment and later language ability.     

Strategies in assessing the need for updating evidence-based guidelines for six clinical topics: an exploration of two search methodologies

BACKGROUND: Because of the expense of updating practice guidelines, recent attention has focused on approaches that can reliably assess any updating required. Shekelle et al. (Journal of the American Medical Association 2001, 286, 1461-7) proposed using limited literature searches with expert involvement to reduce resources used in assessing whether a guideline needs updating. OBJECTIVES: This study compared Shekelle's method and the traditional systematic review method regarding comprehensiveness and effort. METHODS: Two research teams translated critical key questions on screening test treatments and outcomes to Medical Subjects Headings (MeSH) and search strategies. They refined Shekelle's method over three iterations, seeking greater efficiency. Using both methods independently, teams assessed the need to update six topics from the 1996 Guide to Clinical Preventive Services (US Preventive Services Task Force). Outcomes included completeness of study identification, importance of missed studies and effort involved. RESULTS: The revised review approach produced fewer citations than the traditional approach and saved time, identifying fewer eligible studies than the traditional approach. None of the studies missed was rated important by the experts consulted. CONCLUSIONS: The revised review approach provides an acceptable method for judging whether a guideline requires updating. Librarians were an integral part of the research process that streamlined the searches.     

Classroom Questioning with Immediate Electronic Response: Do Clickers Improve Learning?

A number of studies have focused on how students and instructors feel about digital learning technologies. This research is focused on the substantive difference in learning outcomes between traditional classrooms and classrooms using clickers. A randomized block experimental design involving four sections of undergraduate Operations Management classes was used to determine if clicker systems increase student learning of both quantitative and conceptual material in Operations Management. Learning was measured using the difference between the scores on an entrance examination and the final examination. The findings of this research provide evidence that the use of immediate feedback using a technology like clickers can have a positive impact on student learning as measured by test scores.     

Learners and learning contexts: international perspectives on new alignments for the digital age

Educational technology research and development - Twelve papers representing 59 authors from 16 different nations are included in this special issue addressing the theme of ‘Learners and...