Using compositional data analysis to explore accumulation of sedentary behavior,physical activity and youth health

Purpose:The study aimed to describe youth time-use compositions,focusing on time spent in shorter and longer bouts of sedentary behavior and physical activity(PA),and to examine associations of these time-use compositions with cardiometabolic biomarkers.Methods:Accelerometer and cardiometabolic biomarker data from 2 Australian studies involving youths 7-13 years old were pooled(complete cases with accelerometry and adiposity marker data,n=782).A 9-component time-use composition was formed using compositional data analysis:time in shorter and longer bouts of sedentary behavior;time in shorter and longer bouts of light-,moderate-,or vigorous-intensity PA;and"other time"(i.e.,non-wear/sleep).Shorter and longer bouts of sedentary time were defined as<5 min and>5 min,respectively.Shorter bouts of light-,moderate-,and vigorous-intensity PA were defined as<1 min;longer bouts were defined as≥1 min.Regression models examined associations between overall time-use composition and cardiometabolic biomarkers.Then,associations were derived between ratios of longer activity patterns relative to shorter activity patterns,and of each intensity level relative to the other intensity levels and"other time",and cardiometabolic biomarkers.Results:Confounder-adjusted models showed that the overall time-use composition was associated with adiposity,blood pressure,lipids,and the summary score.Specifically,more time in longer bouts of light-intensity PA relative to shorter bouts of light-intensity PA was significantly associated with greater body mass index z-score(zBMI)(β=1.79;SE=0.68)and waist circumference(β=18.35,SE=4.78).When each activity intensity was considered relative to all higher intensities and"other time",more time in light-and vigorous-intensity PA,and less time in sedentary behavior and moderate-intensity PA,were associated with lower waist circumference.Conclusion:Accumulating PA,particularly light-intensity PA,in frequent short bursts may be more beneficial for limiting adiposity compared to accumulating the same amount of PA at these intensities in longer bouts.     

A novel surface modification technique for forming porous polymer monoliths in poly(dimethylsiloxane)

A new method of surface modification is described for enabling the in situ formation of homogenous porous polymer monoliths (PPMs) within poly(dimethylsiloxane) (PDMS) microfluidic channels that uses 365 nm UV illumination for polymerization. Porous polymer monolith formation in PDMS can be challenging because PDMS readily absorbs the monomers and solvents, changing the final monolith morphology, and because PDMS absorbs oxygen, which inhibits free-radical polymerization. The new approach is based on sequentially absorbing a non-hydrogen-abstracting photoinitiator and the monomers methyl methacrylate and ethylene diacrylate within the walls of the microchannel, and then polymerizing the surface treatment polymer within the PDMS, entangled with it but not covalently bound. Four different monolith compositions were tested, all of which yielded monoliths that were securely anchored and could withstand pressures exceeding the bonding strength of PDMS (40 psi) without dislodging. One was a recipe that was optimized to give a larger average pore size, required for low back pressure. This monolith was used to concentrate and subsequently mechanical lyse B lymphocytes.     

10 Jahre Arbeitsausschuss Gutes Spielzeug

Ohne Zusammenfassung     

Editorial

If the founders and editors of the International Journal ofPublic Opinion Research described the ideal spectrum of thejournal’s content, we would all very likely enumeratethe following five dimensions, usually in a comparative and/orinternational context: theories about the dynamics of publicopinion, methodological problems and developments, the roleof the news media in public communication, public opinion researchas a social and political problem, and public opinion data on     

Designing interdisciplinary instruction: exploring disciplinary and conceptual differences as a resource

This article presents a “telling case” of an interdisciplinary, team-teaching experience that explores how participants eschewed ethnocentricism of their fields of study in order to learn from each other, while providing instruction to students and analysing data collected from the class (a graduate course on literature and pedagogy). Through the process, the participants (a professor of English education and a professor of literature) ground the perspectives of literary interpretation in their field of study and languaculture, and developed a conceptual framework that guided their interactions and analysis of the discursive actions of the class. An ethnographic perspective served as the conceptual frame and informed how the participants observed, described, and developed claims about classroom interactions. Through this study, the participants answer calls for more examples of how faculty in higher education engage in interdisciplinary teaching and research and the need for faculty to develop conceptual ethnographic frameworks for their collaborations.     

Differences in the Processing of Prefixes and Suffixes Revealed by a Letter-Search Task

A letter-search task was used to test the hypothesis that affixes are chunked during morphological processing and that such chunking might operate differently for prefixes and suffixes. Participants had to detect a letter target that was embedded either in a prefix or suffix (e.g., ‘R’ in propoint or filmure) or in a non-prefix beginning or non-suffix ending (e.g., ‘R’ in cropoint or filmire). Prefixed and suffixed letter-strings comprised real stems and affixes but never formed a real word. Effects of letter cluster frequency were also investigated by manipulating the frequency of non-affix beginnings and endings. Letter search took longer in suffixes compared with non-suffix endings but not for prefixes compared with non-prefix beginnings. Moreover, performance was not affected by letter cluster frequency. We interpret our findings in the light of recent accounts of morpho-orthographic segmentation and the different function of prefixes and suffixes.     

E-government research in the United States

The purpose of this exploratory study is to review scholarly publications and assess egovernment research efforts as a field of study specific to the United States e-government environment. Study results reveal that researchers who focus on the U.S. e-government environment assess specific e-government topics at the federal, state, and local levels; however, there are gaps in the research efforts by topic areas and across different levels of government, which indicate opportunities for future areas of research. Results also find that a multitude of methodology approaches are used to assess e-government. Issues, however, exist that include lack of or weak presentations of methodologies in publications, few studies include multi-method evaluation approaches for data collection and analysis efforts, and few studies take a theory-based approach to understanding the U.S. e-government environment.