Instruments to assess physical activity are needed for (inter)national surveillance systems and comparison.
Male and female adults were recruited from diverse sociocultural, educational and economic ...backgrounds in 9 countries (total n = 2657). GPAQ and the International Physical Activity Questionnaire (IPAQ) were administered on at least 2 occasions. Eight countries assessed criterion validity using an objective measure (pedometer or accelerometer) over 7 days.
Reliability coefficients were of moderate to substantial strength (Kappa 0.67 to 0.73; Spearman's rho 0.67 to 0.81). Results on concurrent validity between IPAQ and GPAQ also showed a moderate to strong positive relationship (range 0.45 to 0.65). Results on criterion validity were in the poor-fair (range 0.06 to 0.35). There were some observed differences between sex, education, BMI and urban/rural and between countries.
Overall GPAQ provides reproducible data and showed a moderate-strong positive correlation with IPAQ, a previously validated and accepted measure of physical activity. Validation of GPAQ produced poor results although the magnitude was similar to the range reported in other studies. Overall, these results indicate that GPAQ is a suitable and acceptable instrument for monitoring physical activity in population health surveillance systems, although further replication of this work in other countries is warranted.
Migration has been hypothesised to be selective on health but this healthy migrant hypothesis has generally been tested at destinations, and for only one type of flow, from deprived to better-off ...areas. The circulatory nature of migration is rarely accounted for. This study examines the relationship between different types of internal migration and adult mortality in Health and Demographic Surveillance System (HDSS) populations in West, East, and Southern Africa, and asks how the processes of selection, adaptation and propagation explain the migration-mortality relationship experienced in these contexts. The paper uses longitudinal data representing approximately 900 000 adults living in nine sub-Saharan African HDSS sites of the INDEPTH Network. Event History Analysis techniques are employed to examine the relationship between all-cause mortality and migration status, over periods ranging from 3 to 14 years for a total of nearly 4.5 million person-years. The study confirms the importance of migration in explaining variation in mortality, and the diversity of the migration-mortality relationship over a range of rural and urban local areas in the three African regions. The results confirm that the pattern of migration-mortality relationship is not exclusively explained by selection but also by propagation and adaptation. Consequences for public health policy are drawn.
•This study simultaneously test known hypotheses relating to migration and mortality.•A methodological framework identifies selection, adaptation and propagation effects.•Migration status and exposure are sufficient to identify above effects.•HDSS data reveal important differences in selection and universal adaptation.•Approach helps to identify target populations for local health interventions.
The increasing availability of autonomous Unmanned Aerial Vehicles (UAVs) has provided an emerging way for extensive surveillance and monitoring in civilian and military with the advantages of high ...flexibility, mobility, and bird's-eye features. To mitigate the limitations of on-board energy and computation capacity, UAVs usually offload intensive computation tasks (e.g., image/video processing) to base-station-enabled mobile-edge computing (MEC) facilities. However, base stations are not always available in rural areas. To this end, we propose to offload computation-intensive tasks to Unmanned Ground Vehicles (UGVs), which have fixed routes (i.e., highways and roads). However, the UAV-UGV wireless communication may disclose the offloading information to potential eavesdroppers. Besides, such UGVs have sufficient computation slots but may run out of the target area after a period of traveling. In this paper, the tasks cached on UAVs are modeled as a stochastic queue, and a secure communication strategy to offload the cached tasks from UAVs to UGVs is proposed. We try to maximize the average utility of such a UAV-UGV collaboration with respect to latency, power, velocity, anti-collision, and distance. To solve this non-convex mixed integer nonlinear programming problem, a fast converging and computationally efficient iterative algorithm is investigated utilizing the block coordinate descent method and the successive convex approximation technique. Experiment results demonstrate that our algorithm consistently outperforms the state-of-the-art scheme, significantly improving the average utility of the system.
Limitations in laboratory diagnostic capacity impact population surveillance of COVID-19. It is currently unknown whether participatory surveillance tools for COVID-19 correspond to ...government-reported case trends longitudinally and if it can be used as an adjunct to laboratory testing. The primary objective of this study was to determine whether self-reported COVID-19-like illness reflected laboratory-confirmed COVID-19 case trends in Ontario Canada.
We retrospectively analyzed longitudinal self-reported symptoms data collected using an online tool-Outbreaks Near Me (ONM)-from April 20th, 2020, to March 7th, 2021 in Ontario, Canada. We measured the correlation between COVID-like illness among respondents and the weekly number of PCR-confirmed COVID-19 cases and provincial test positivity. We explored contemporaneous changes in other respiratory viruses, as well as the demographic characteristics of respondents to provide context for our findings.
Between 3,849-11,185 individuals responded to the symptom survey each week. No correlations were seen been self-reported CLI and either cases or test positivity. Strong positive correlations were seen between CLI and both cases and test positivity before a previously documented rise in rhinovirus/enterovirus in fall 2020. Compared to participatory surveillance respondents, a higher proportion of COVID-19 cases in Ontario consistently came from low-income, racialized and immigrant areas of the province- these groups were less well represented among survey respondents.
Although digital surveillance systems are low-cost tools that have been useful to signal the onset of viral outbreaks, in this longitudinal comparison of self-reported COVID-like illness to Ontario COVID-19 case data we did not find this to be the case. Seasonal respiratory virus transmission and population coverage may explain this discrepancy.
PDF
