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The potential of passively generated big data sources in transport modelling is well‐recognised. However, assessing their accuracy and suitability for policymaking remains challenging due to the lack of ground‐truth (GT) data for validation. This study evaluates the accuracy of inferring human mobility patterns from global positioning system (GPS), call detail records (CDR), and global system for mobile communication (GSM) data. Using outputs from an agent‐based simulation platform (MATSim) as 'synthetic GT' (SGT), synthetic GPS, CDR, and GSM data were generated, considering their positional disturbances and conventional spatiotemporal resolutions. Mobility information, including activity location, departure time, and trajectory distance, derived from the synthetic data, was compared with SGT to evaluate the accuracy of passive trajectory data at both disaggregate and aggregate levels. The results indicated a higher accuracy of GPS data in identifying stay locations at high resolution. But, GSM data at a lower resolution effectively accounted for over 80% of the variability in stay locations. Comparisons of departure time distribution and travel distance revealed higher measurement errors in GSM and CDR data than in GPS data. The proposed simulation‐based accuracy assessment framework will aid transport planners select the most suitable data for specific analyses and understand the potential margin of error involved. [ABSTRACT FROM AUTHOR]

A Van Allen Probes observation of a high‐density duct alongside whistler‐mode wave activity shows several distinctive characteristics: (a)—within the duct, the wave normal angles (WNA) are close to zero and the waves have relatively large amplitudes, this is expected from the classic conceptualization of ducts. (b)—at L‐shells higher than the duct's location a large "shadow" is present over an extended region that is larger than the duct itself, and (c)—the WNA on the earthward edge of the duct is considerably higher than expected. Using ray‐tracing simulations it is shown that rays fall into three categories: (a) ducted (trapped and amplified), (b) reflected (scattered to resonance cone and damped), and (c) free (non‐ducted). The combined macroscopic effect of all these ray trajectories reproduce the aforementioned features in the spacecraft observation. Plain Language Summary: The near‐earth space environment is a complex system that is dominated by the interaction of radio waves with charged particles. A class of radio waves known as "whistler‐mode" waves, have a drastic impact on energetic particles; understanding properties of whistler waves is thus of considerable interest. It is well‐known that whistler‐mode waves can be trapped within "ducts," which are perturbations in plasma density. Ducts act like pipes that guide waves over thousands of kilometers and routinely connect one hemisphere to the other. Although ducting has been studied for over 75 years, prior research has primarily focused on this guiding effect. Instead, we use spacecraft observations alongside computer simulations to show that ducts have a dramatic effect on waves that are never directly confined to the duct. It is found that a "shadow" region extends far outside the duct caused by trapped waves that leave behind a gap in power. Furthermore, external waves also collide with the duct and ride along the edge at an unexpectedly oblique angle. The results of the work indicate that wave propagation in the vicinity of ducts is more complex than previously thought and must be carefully examined for an accurate understanding of the space environment. Key Points: A Van Allen Probes duct observation shows that whistler waves are field aligned inside, absent on one side, and oblique on the otherRaytracing shows that rays are either trapped in the duct, reflected toward the resonance cone, or free (non‐ducted)Power density and wave normal angle distribution constructed from 10,000 rays reproduces the observed wave properties [ABSTRACT FROM AUTHOR]

Background: Hypertension is a major public health concern in low-and middle-income countries. A nationwide Health, Population, and Nutrition Sector Development Program in Bangladesh has been shown to be effective in resource-poor settings. This article aims to investigate whether the prevalence and determinants of adult hypertension changed from 2011 to 2018. Methods: The determinants of adult hypertension were assessed in 2011 and 2018 data of Bangladesh Demographic and Health surveys. These two surveys included both men and women over the age of 34 years and measured their blood pressure, weight, height, and other covariates. For both surveys, we estimated the age-standard prevalence of hypertension and relative, attributable and mediated risk of determinants of hypertension using hierarchical mixed-effects sequential Poisson regression models. Results: The prevalence of adult hypertension increased by 10.9% from 29.5% in 2011 to 40.4% in 2018. The nationwide awareness program on the Health, Population and Nutrition Sector changed the risks associated with hypertension determinants over the years. During 2011, Socio-economic status (SES) was a major distal determinant of adult hypertension, explaining 21% of population-attributable risk (ART). However, other factors accounted for 90% of risk, mainly by excessive body weight (51%) and awareness of hypertension (39%). In contrast, SES only explained 16% of ART risk, with 97% of the risk mediated by excessive body weight (55%) and awareness of hypertension (41%). Conclusion: The study results highlight that hypertension among older adult was significantly increased over the six-year period. Specially, the socio-economic status, awareness of hypertension and excessive body weight were the significant determinants. Being awareness of hypertension and excessive body weight changed the causal pathways of socio-economic status. The results also highlight the value of studying the effect of non-communicable disease awareness programs to enhance our comprehension of factors influencing health. [ABSTRACT FROM AUTHOR]

Understanding children's mobility behaviour and parents escorting practices are important to developing a children-friendly society. But only a few studies concerning children's mobility behaviour have focused on developing countries. In this study, we attempted to develop an econometric model to understand escorting practices in a developing country. A multinomial logit (MNL) model is developed using travel diary data of 398 elementary school-going children, inhabiting in Chattogram City Corporation (CCC) area of Bangladesh. We have considered different combinations of environmental (both school and neighbourhood environment), socio-cultural, household, and personal factors to explain children's independent mobility behaviour for both school and discretionary trip purposes. The findings suggested that children's individual (e.g. education level) and parents' sociodemographic (e.g. income, access to cars, mother's education level) facilities available at school, and built-environmental factors (e.g. commercial density, road density, land use mix and proximity to open spaces) are significantly associated with parent's choice for chauffeuring their children in CCC area. Results will be useful to planners and policy makers for formulating effective measures to promote children's independent mobility and will be a guideline for urban planners to include children's mobility demand for the neighbourhood as well as city design. [ABSTRACT FROM AUTHOR]

The accurate evaluation of public transport (PT) services in developing countries is a challenging task due to a lack of reliable data and formal guidelines. The aim of this study was to develop a framework addressing these data limitations and quantify PT performance using output‐oriented Data Envelopment Analysis (DEA). The local bus service operation of Chattogram City Corporation area of Bangladesh was used as a case study. A performance assessment inventory was developed identifying the major stakeholders related to local bus service operations. The relative efficiencies of different bus routes (from users' and operators' perspectives) were estimated using the DEA model, which incorporated data from a semi‐structured questionnaire survey linked with the inventory. The PT authority also ranked all bus routes according to their degree of efficiency. Results indicated that relative efficiency scores in various routes varied according to the stakeholders' perspectives. A range of different parameters were considered when evaluating the performance of the service. The proposed inventory and framework would be useful for policymakers and urban planners in sequencing and prioritising different routes. This optimisation process would provide improved transport services to the general public. [ABSTRACT FROM AUTHOR]

This paper explores the impact of COVID-19 on shopping behavior in two neighboring developing economies: Bangladesh and India. While the previous studies investigating the impact of COVID-19 on shopping behavior have relied on Revealed Preference (RP) data, this paper combines RP and Stated Preference (SP) data to develop joint RP-SP discrete choice models. This makes it possible to quantify the relative impact of the situational contexts on the choice of shopping modes of households and to capture the associated heterogeneity arising from the characteristics of the households. Further, comparison of the data and the estimated model parameters of the two countries with substantial socio-cultural similarities provide insights about how differences in the state of e-commerce can lead to different levels of inertia in continuing the pre-COVID behavior. The results will be useful to planners and policymakers for predicting the shopping modes in different future scenarios and formulating effective restriction measures. [ABSTRACT FROM AUTHOR]

The occurrence of heavy rainfall in the south-eastern hilly region of Bangladesh makes this area highly susceptible to recurrent flash flooding. As the region is the commercial capital of Bangladesh, these flash floods pose a significant threat to the national economy. Predicting this type of flooding is a complex task which requires a detailed understanding of the river basin characteristics. This study evaluated the susceptibility of the region to flash floods emanating from within the Karnaphuli and Sangu river basins. Twenty-two morphometric parameters were used. The occurrence and impact of flash floods within these basins are mainly associated with the volume of runoff, runoff velocity, and the surface infiltration capacity of the various watersheds. Analysis showed that major parts of the basin were susceptible to flash flooding events of a 'moderate'-to-'very high' level of severity. The degree of susceptibility of ten of the watersheds was rated as 'high', and one was 'very high'. The flash flood susceptibility map drawn from the analysis was used at the sub-district level to identify populated areas at risk. More than 80% of the total area of the 16 sub-districts were determined to have a 'high'-to-'very-high'-level flood susceptibility. The analysis noted that around 3.4 million people reside in flash flood-prone areas, therefore indicating the potential for loss of life and property. The study identified significant flash flood potential zones within a region of national importance, and exposure of the population to these events. Detailed analysis and display of flash flood susceptibility data at the sub-district level can enable the relevant organizations to improve watershed management practices and, as a consequence, alleviate future flood risk. [ABSTRACT FROM AUTHOR]

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Lack of access to clean water is among the most pressing environmental problems in developing countries, where diarrheal disease kills nearly 700,000 children per year. While inexpensive and effective practices such as chlorination and hand washing with soap exist, efforts to motivate their use by emphasizing health benefits have seen only limited success. This paper measures the effect of messages appealing to negative emotions (disgust at consumption of human feces) and social pressure (shame at being seen consuming human feces) on hand-washing behavior and use of and willingness to pay for water chlorination among residents of slum compounds in Dhaka, Bangladesh. Neither the traditional, health-based message nor the new disgust-and-shame message led to high levels of chlorination during a free trial, nor to high willingness to pay for the chlorine at the end of the free trial. Provision of low-cost hand-washing facilities did increase hand washing, although the effect size is modest. [ABSTRACT FROM AUTHOR]

Rationale: There is little evidence for the efficacy of handwashing for prevention of influenza transmission in resource-poor settings. We tested the impact of intensive handwashing promotion on household transmission of influenza-like illness and influenza in rural Bangladesh. Methods: In 2009–10, we identified index case-patients with influenza-like illness (fever with cough or sore throat) who were the only symptomatic person in their household. Household compounds of index case-patients were randomized to control or intervention (soap and daily handwashing promotion). We conducted daily surveillance and collected oropharyngeal specimens. Secondary attack ratios (SAR) were calculated for influenza and ILI in each arm. Among controls, we investigated individual risk factors for ILI among household contacts of index case-patients. Results: Among 377 index case-patients, the mean number of days between fever onset and study enrollment was 2.1 (SD 1.7) among the 184 controls and 2.6 (SD 2.9) among 193 intervention case-patients. Influenza infection was confirmed in 20% of controls and 12% of intervention index case-patients. The SAR for influenza-like illness among household contacts was 9.5% among intervention (158/1661) and 7.7% among control households (115/1498) (SAR ratio 1.24, 95% CI 0.92–1.65). The SAR ratio for influenza was 2.40 (95% CI 0.68–8.47). In the control arm, susceptible contacts <2 years old (RRadj 5.51, 95% CI 3.43–8.85), those living with an index case-patient enrolled ≤24 hours after symptom onset (RRadj 1.91, 95% CI 1.18–3.10), and those who reported multiple daily interactions with the index case-patient (RRadj 1.94, 95% CI 1.71–3.26) were at increased risk of influenza-like illness. Discussion: Handwashing promotion initiated after illness onset in a household member did not protect against influenza-like illness or influenza. Behavior may not have changed rapidly enough to curb transmission between household members. A reactive approach to reduce household influenza transmission through handwashing promotion may be ineffective in the context of rural Bangladesh. Trial Registration: ClinicalTrials.gov [ABSTRACT FROM AUTHOR]