The links between adolescent biological maturity, physical activity and fat mass development, and subsequent cardiometabolic risk in young adulthood

The metabolic syndrome has become a major public health challenge world-wide and, at least in the industrialized world, the prevalence of the metabolic syndrome is increasing. There is evidence to show that biological and lifestyle risk factors for metabolic syndrome are present in adolescence, which suggests that the antecedents of the disease may lie in early life. The period of adolescence is characterized by a decline in physical activity (PA; lack of PA is a lifestyle risk factor for metabolic syndrome) and an increase in fat mass deposition (a biological risk factor for metabolic syndrome). Therefore, investigating how the development of these two variables relates to adult cardiometabolic risk is important to fuel early intervention. A factor which has the potential to influence these two risk factors, and thus ultimately the metabolic syndrome, is the timing of biological maturity (i.e. whether an individual is early, average or late maturing when compared to peers of the same age). The influence of biological maturity has largely been overlooked in previous research; therefore, the general objective of this thesis was to investigate the associations between biological maturity, adolescent PA and fat mass development, and young adult cardiometabolic risk. Three studies were necessary to realize this objective, and together help to elucidate the role of biological maturity in the adolescent decline in physical activity, fat development, and the development of adult metabolic syndrome. Ultimately, this information will aid in the development and implementation of interventions to decrease prevalence of metabolic syndrome. Study 1: The purpose of study 1 was to investigate whether observed gender differences in objectively measured PA in children (8 to 13 years) are confounded by biological maturity differences. Methods: Four hundred and one children (194 boys and 207 girls) volunteered for this study. An Actigraph accelerometer was used to obtain 7 consecutive days of minute-by-minute PA data on each participant. Minutes of moderate to vigorous PA per day (MVPA), continuous minutes of MVPA per day (CMVPA), and minutes of vigorous PA per day (VPA) were derived from the accelerometer data. Age at peak height velocity (APHV), an indicator of somatic maturity, was predicted and individuals aligned by this biological age (years from APHV). Gender differences in the PA variables were analyzed using a two-way (gender X age) ANOVA. Results: Levels of PA decreased with increasing chronological ages in both genders (

The Effect of the Environment on the Corrosion Products and Corrosion Rates on Gas Transmission Pipelines

This thesis reports a series of investigations examining external corrosion processes along gas transmission pipelines. TransCanada PipeLines Ltd. (TCPL) has developed six proposed corrosion scenarios to describe external pipeline corrosion, based primarily on corrosion products and corrosion rates (CRs) observed at field sites. The six proposed corrosion scenarios can be divided into two groups: abiotic and biotic. The three abiotic corrosion scenarios are (1) anaerobic corrosion, (2) aerobic corrosion, and (3) anaerobic corrosion turning aerobic; while (4) anaerobic corrosion with microbial effects, (5) aerobic corrosion turning anaerobic with microbial effects, and (6) anaerobic corrosion with microbial effects turning aerobic comprise the three biotic corrosion scenarios. The primary objective of this project was to develop a series of laboratory-based corrosion mechanisms in order to validate the six proposed corrosion scenarios. The approach used was to electrochemically monitor the evolution in corrosion behaviour of steel exposed to simulated groundwaters anticipated near exposed pipelines. The primary electrochemical techniques used were corrosion potential (ECORR) measurements to monitor redox conditions, linear polarization resistance (LPR) measurements to calculate CRs, and electrochemical impedance spectroscopy (EIS) measurements to monitor changes in steel/film properties. A secondary objective was to match corrosion products (i.e., “rusts”) produced electrochemically to those reported from field investigations using surface analytical techniques. Scanning electron microscopy (SEM) and optical microscopy were used to analyze corrosion product morphologies, while elemental composition and iron phase identification were examined by energy dispersive X-ray (EDX) spectroscopy and Raman spectroscopy, respectively. Reports indicate that seasonal variations in the water table can alter the distribution of anaerobic and aerobic sites, which can be particularly damaging to pipeline integrity. Anaerobic corrosion is associated with wet soil conditions and is the most prevalent corrosion scenario observed in the field. To understand steel-oxygen interactions, the influence of traces of dissolved oxygen on pretreated steel was investigated. Adventitious oxygen was found to initiate a slow evolution in film properties on pretreated steel leading to a drastic film transition (i.e., a rapid rise in ECORR coupled to a large increase in CR). Should soils dry, oxygen tends to diffuse more readily through the soil to the pipe surface and drives steel corrosion. To better understand the effect of changes to redox conditions on pipelines, long term corrosion measurements were made by monitoring the changes in corrosion behaviour of pretreated carbon steel under alternating anaerobic-aerobic cycles. With increasing cycle number the corrosion process becomes localized at a small number of locations, consistent with the formation of tubercles. As expected, periods of aerobic corrosion were associated with more positive potentials and higher CRs; whereas anaerobic corrosion yielded more negative potentials and lower CRs. Microbially induced corrosion (MIC) is particularly damaging to pipeline integrity as soils containing microbes generate sulphide, which can significantly alter the groundwater chemistry. Difficulties in simulating complex field conditions in the laboratory have meant that only a limited number of experiments have accurately characterized the complex chemical and biological interactions between bacteria and steel. Several biological microcosms were investigated to further understand how variations in nutrient levels affect steel-microbe interactions. Raman analyses indicated mackinawite (Fe1+xS) was the dominant iron sulfide phase formed both by microbes and inorganic sulphide. In order to avoid biological complications, and to improve our understanding of Fe-S interactions, inorganic HS– was used as a model system to aid in the interpretation of steel undergoing MIC. A series of five corrosion potential measurements investigated the effect of variations in redox conditions and inorganic sulphide concentration on the corrosion behaviour of pretreated and untreated carbon steel. Field reports have indicated the highest CR expected for external corrosion occurred when pipelines, initially under anaerobic MIC control, transformed to aerobic corrosion. The laboratory results support field sampling methods as the highest CRs observed occurred when both sulphide and oxygen were present. In addition, under anaerobic conditions with sulphide, CRs were lower for freshly exposed steel compared to anaerobically pre-corroded steel. This suggests pre-corroded surfaces prevent the formation of passivating iron sulphide films

Alien Registration- Hathaway, Della (Caribou, Aroostook County)

https://digitalmaine.com/alien_docs/26503/thumbnail.jp

Lack of knowledge of physical activity guidelines: can physical activity promotion campaigns do better?

Objectives To identify the prevalence of knowledge of the current UK physical activity guidelines which were introduced in 2011 and prior physical activity guidelines (30 min on 5 days each week) within two large samples of UK adult's. To investigate whether knowledge of physical activity guidelines differs according to demographics such as ethnicity, age, education and employment status. Design Descriptive cross-sectional study comparing two distinctive adult samples. Setting National survey and online-administered survey conducted in England. Participants The 2007 Health Survey for England provides data on knowledge of physical activity guidelines from 2860 UK adults (56% women, 89% white, 63% under 45 years old). In 2013, an online survey was disseminated and data were collected from 1797 UK adults on knowledge of the most recent physical activity guidelines. The 2013 sample was 70% women, 92% white and 57% under 45 years old. All adults in both samples were >18 years old and without illnesses/disorders likely to restrict physical activity. Main outcomes Knowledge of physical activity guidelines in 2007 and 2013. Demographic correlates of knowledge of moderate-to-vigorous physical activity guidelines. Results 18% of the 2013 sample accurately recalled the current physical activity guidelines compared with 11% of the 2007 sample who accurately recalled the previous guidelines. The differences in knowledge of physical activity guidelines existed for marital status, gender, age, education and employment status within both 2007 and 2013 samples (p<0.05). Men with lower education and employment status (unemployed including student and retired) and older adults were less likely to know physical activity guidelines (p<0.05). Knowledge of physical activity guidelines remained higher in the 2013 sample after controlling for demographic differences (p<0.05). Conclusions Disadvantaged population groups are less knowledgeable about physical activity guidelines. Although knowledge of physical activity guidelines appears to have increased in recent years demographic disparities are still evident. Efforts are needed to promote health information among these groups

Teacher perceptions on the delivery and implementation of movement integration strategies: the CLASS PAL (Physically Active Learning) Programme

Children sit for extended periods in the school classroom. Movement integration (MI) methods (e.g. active breaks, physically active lessons) could be used to break/reduce sitting time and improve classroom behaviour and engagement. Limited evidence is available on teacher perceptions of what influences the implementation of MI. Interviewed primary school teachers reported factors perceived to influence implementation at a variety of levels including individual (e.g. teacher and pupil characteristics, time, behavioural management) and school (e.g. whole school approach; and external to school expectations). In addition suggestions for increasing adoption and implementation of MI (e.g. communicating MI initiatives to schools) were identified

Posture optimization algorithm for large structure assemblies based on skin model

Geometric deviations inevitably occur in product manufacturing and seriously affect the assembly quality and product functionality. Assembly simulations on the basis of computer-aided design (CAD) package could imitate the assembly process and thus find out the design deficiencies and detect the assemblability of the components. Although lots of researches have been done on the prediction of assembly variation considering the geometric errors, most of them only simplify the geometric variation as orientation and position deviation rather than the manufacturing deformation. However, in machinery manufacturing, even if the manufacturing defects are limited, they could propagate and accumulate through components and lead to a noncompliant assembly. Recently, many point-based models have been applied to assembly simulation; however they are mainly interested in simulating the resulting positions of the assembled parts and lack the consideration of the postprocessing after positioning. This paper enriches the complete assembly simulation process based on skin model and presents a simple and effective posture evaluation and optimization method. The studied approach includes a software algorithm applied to evaluate the contact state of the assembly parts and a mathematical model based on the particle swarm optimization to acquire the optimal assembly posture. To verify the efficiency and feasibility of the proposed method, a case study on the aircraft wing box scaling model assembly is performed

Awareness of moderate-to-vigorous physical activity: Can information on guidelines prevent overestimation?

BACKGROUND: Mass-media campaigns such as Change4Life use messaging to promote physical activity guidelines. Raising knowledge of MVPA guidelines within UK adults is a main goal of current mass media campaigns aimed at increasing engagement in MVPA. As this may help to inform accurate perceptions of adults’ own MVPA level it is an important area of investigation. Subjective norms, health status and normal walking intensity may also influence adult’s awareness of their own MVPA behaviour. The aim of this study was to examine the hypothesis that greater knowledge of MVPA guidelines, supportive subjective norms, lower self-reported health status and intensity of typical walking pace are associated with accurate awareness of MVPA engagement within a sample of UK adults. METHODS: A cross-sectional study of UK adults was conducted. UK adults who subscribed to the National Academic Mailing List Service (JISCMail) were sent an invitation to complete an online survey. 1,724 UK adults completed the online survey which included items on minutes spent in MVPA, awareness of MVPA using constructs highlighted by the precaution adoption process model, subjective norms, knowledge of guidelines, health status and demographics. RESULTS: The sample was 70% female, 57% aged under 45, 93% White and 69% in full-time employment. 62% reported their health to be above average, while 62% demonstrated accurate awareness of their own physical activity level, only 18% correctly reported the MVPA guidelines and 51% reported high subjective norms towards MVPA. Logistic regression analyses identified high subjective norms (OR = 1.84, CI: 1.29, 2.63, p = .001), average or below average health status (OR = .71, CI: .53 .97, p = .001), and a self-reported regular walking pace of moderate-to-vigorous (OR = 1.31, CI: 1.05, 1.63, p = .02) to be associated with accurate MVPA awareness. Knowledge of MVPA guidelines was not associated with MVPA awareness. CONCLUSIONS: Mass media campaigns, such as Change4Life, inform the general public of MVPA guidelines. Campaign messages may be more influential targeting subjective norms instead of knowledge of guidelines, thereby raising awareness of personal MVPA behaviour amongst inactive adults and increasing motivation to engage in more MVPA