Discrepancies in accelerometer-measured physical activity in children due to cut-point non-equivalence and placement site

Abstract This study examined dissonance in physical activity (PA) between two youth-specific hip-derived intensity cut-points for the Actiwatch (AW), and compared PA between hip and wrist placements using site-specific cut-points. Twenty-four children aged 11.2?±?0.5 years wore the AW on the right hip and non-dominant wrist during a typical school day. Minutes of sedentary behaviour and vigorous activity were greater using Puyau et al. (2002) cut-points, but light, moderate, and moderate-to-vigorous (MVPA) were greater when derived using Puyau et al. (2004) cut-points (P?相似文献   

Fault reconstruction using a LPV sliding mode observer for a class of LPV systems

This paper proposes a new sliding mode observer for fault reconstruction, applicable for a class of linear parameter varying (LPV) systems. Observer schemes for actuator and sensor fault reconstruction are presented. For the actuator fault reconstruction scheme, a virtual system comprising the system matrix and a fixed input distribution matrix is used for the design of the observer. The fixed input distribution matrix is instrumental in simplifying the synthesis procedure to create the observer gains to ensure a stable closed-loop reduced order sliding motion. The ‘output error injection signals’ from the observer are used as the basis for reconstructing the fault signals. For the sensor fault observer design, augmenting the LPV system with a filtered version of the faulty measurements allows the sensor fault reconstruction problem to be posed as an actuator fault reconstruction scenario. Simulation tests based on a high-fidelity nonlinear model of a transport aircraft have been used to demonstrate the proposed actuator and sensor FDI schemes. The simulation results show their efficacy.     

The reliability and validity of the pupil behaviour questionnaire: a child classroom behaviour assessment tool

ABSTRACT

This paper assesses the reliability and validity of the teacher-completed Pupil Behaviour Questionnaire (PBQ), by comparing it to the already extensively validated teacher-completed Strengths and Difficulties Questionnaire (SDQ). Participants included 2074 primary school children participating in a universal school-based trial and 41 vulnerable children who were taking part in a study exploring the impact of exclusion from school. Exploratory factor analysis results (first factor accounts for 80.8% of the variation in the items) and the high Cronbach’s alpha value of 0.85 indicate that the PBQ consists of one substantive factor/dimension. Strong correlations between the total PBQ score and the conduct sub-scale (Spearman’s correlation coefficient (r_s) = 0.67) and total difficulties score (r_s = 0.59) of the SDQ indicate convergent validity. This study suggests that the PBQ is a reliable measure, and provides some evidence of validity. Further work is needed to test the PBQ in an older, more diverse populations and to measure sensitivity to change.     

The influences of guiding cues on motor skill autonomy in rats

How does the effectiveness of guiding cues influence the development of motor skill autonomy? We utilized two sets of guiding cues (lights vs. reversed-lights conditions) that differed in their effectiveness to control a left–right leverpress sequence in rats. We separately measured the development of stimulus control by panel lights on guiding-cues trials and the development of stimulus control by practice cues on no-cue probe trials within the same sessions. Accuracy in the presence of the guiding cues was acquired faster in the lights condition than in the reversed-lights condition, but subjects in the reversed-lights condition were more able to complete the skill autonomously than those in the lights condition. Throughout acquisition, control by guiding cues and practice cues developed at the same rate in the reversed-lights condition, but control by practice cues (autonomy) developed at a slower rate than did control by guiding cues in the lights condition. At the end of training, subjects that had been exposed to the reversed-lights condition displayed higher levels of autonomy than did those exposed to the lights condition. The less effective guiding cue (reversed-lights) produced greater levels of autonomy than did the more effective cue (lights), even though control by this guiding cue developed more slowly. Thus, guiding your child by the hand too much may reduce his or her ability to complete the task independently. We discuss the similarity to prompt dependence in children with learning disabilities and transfer of stimulus control.     

The Instructional and Emotional Quality of Parent–Child Book Reading and Early Head Start Children's Learning Outcomes

Research Findings: The objective of this study was to understand how two dimensions of parent–child book-reading quality—instructional and emotional—interact and relate to learning in a sample of low-income infants and toddlers. Participants included 81 parents and their children from Early Head Start programs in the rural Midwest. Correlation and multiple regression analyses were used to test the hypothesis that parental book-reading qualities interact and relate to children's concurrent cognitive and language scores. Exploratory analyses examined if patterns of relationships varied for families who had different home languages (i.e., English, Spanish). Results included that book-reading qualities and home language interacted to predict child scores. Practice or Policy: Findings suggest a need to further explore potentially complex patterns of relationships among parental book-reading behaviors and child learning for diverse families. Understanding these patterns could inform the development of culturally-sensitive intervention approaches designed to support high-quality shared book reading.     

Institutional complementarities: The origins of experimentation in China’s plug-in electric vehicle industry

A vast literature on technology transitions within industries suggests that early phases of new technologies are marked by periods of intense experimentation, but we know little about the conditions under which these periods emerge. We apply inductive, grounded theory-building techniques to examine what prompts firms to experiment across one emerging technology platform—plug-in electric vehicles (PEVs)—in China. Triangulating annual vehicle make and model sales data from 2003 to 2016 (plus monthly data from 2010 to 2016); 112 English and Mandarin archival documents from industry, academic, and news outlets; and 51 semi-structured interviews with industry, government, and academic stakeholders, we develop four in-depth case studies. We find that in contrast to the innovation trajectories of multinational and Chinese arms of joint venture (JV) firms, independent domestic Chinese firms (those with no history of international JV partnerships) are undertaking significant experimentation across multiple levels—infrastructure, core system, subsystem, and component—of the emerging PEV technology platform. We propose the concept of “institutional complementarities” to describe how interactions among institutions—here the national JV regulation and local market support and subsidies—may have turned regional markets into protected laboratories, extending the incubation periods for independent domestic firm experimentation. While this diverse experimentation may be an important antecedent of technology transition, consolidation induced by national policy standardization or competitive pressure may be required for PEV innovations to scale beyond their early, protected regional markets.     

The Effectiveness of an Augmented Reality Head-Mounted Display in Learning Skull Anatomy at a Community College

Despite an increase in the use of technology in undergraduate anatomy education, and the rising popularity of online anatomy courses at community colleges in the United States, there have been no reports on the efficacy of augmented reality on anatomy education in this population. The purpose of this study was to test the hypothesis that augmented reality is an effective and engaging tool for learning anatomy in community college students. Participants recruited from Cuyahoga Community College (Cleveland, OH) studied skull anatomy using either traditional tools (i.e., textbook and plastic skull model) or an augmented reality head-mounted display with an interactive virtual skull application. Comparison of knowledge before and following the study period revealed that augmented reality was an effective tool for learning skull anatomy: pre-quiz = 32.7% (± 25.2); mean (± SD), post-quiz = 61.8% (± 19.5); n = 15; t₍₂₈₎ = 3.53; P = 0.001. The traditional tools were equally effective: pre-quiz = 44.9 % (± 18.6), post-quiz = 67.9 % (± 17.3); n = 17; t₍₃₂₎ = 3.73; P = 0.0007. Students rated the augmented reality device as 9.6 (± 1.0); mean (± SD) when asked if it fit the statement “fun to use” on a semantic differential scale from 1 (poor) to 10 (excellent). In conclusion, this study found that augmented reality is an effective and engaging tool for the instruction of skull anatomy at a community college.