Areas Of Low Population Density Research Articles

Resilience of Interurban Public Transport and Impact of COVID-19 on Rural Connectivity in Sparsely Populated Regions

The aim of this research consisted of assessing the effects of the COVID-19 pandemic on the interurban public transport system in a rural region with a sparse population density, considering the number of tickets sold and passengers in each locality, as well as the different connecting lines. From a methodological point of view and with the intention of identifying patterns to explain the behaviour of both the routes and passengers, a series of variables were selected, becoming determining factors that sought to offer a solution to the search for a common trend. Additionally, data processing by the means of statistical analysis and the application of Geographic Information Systems (GIS) tools complemented the procedure. The results obtained in the investigation were provided both by municipality and by interurban routes. An interesting finding of this research was the uneven recovery of the municipalities. The localities closest to the attractor nucleus have recovered more quickly to pre-pandemic mobility levels due to their geographical proximity, larger populations, higher incomes per household, and need to access certain public services. In terms of routes, all the lines showed significant decreases in ticket sales, although with variations. Although passenger numbers have shown a gradual recovery, the initial loss was considerable, and pre-pandemic normality has not been completely achieved. This research provides a comprehensive overview of the changes in interurban mobility over a four-year period. The incorporation of critical variables and the segmentation by municipality and route provide a way to identify discernible patterns of mobility. However, the lack of previous research focusing on the impact of the pandemic in rural areas of low population density restricts the possibility of establishing a comparison and to generalise the findings. The authors consider that future research should include other alternative means of transport in these interurban areas and incorporate variables to characterise passengers, such as age, gender, etc.

Social determinants and drivers of use of SARS-CoV-2 self-tests in a French national cohort study

Abstract Background Self-tests for SARS-CoV-2 became quickly available after the onset of the epidemic. They were especially recommended for high-risk and hard-to-reach populations. This study examines whether self-tests successfully reached vulnerable groups during first months of availability in France. Methods The EpiCov study is a national population-based cohort study conducted in France during the Covid-19 pandemic. Primary outcome variable was use of self-test at last SARS-CoV-2 test, among those who reported testing at least once between May-July 2021. Univariate and multivariate binomial weighted logistic regressions were run, stratified by age group (16-24 yrs, 25-59, 60+), to identify social determinants and drivers of use of self-tests. Results Overall, 11% of the population who tested for SARS-CoV-2 between May-July 2021 reported using a self-test as last test. Demographic factors were highly predictive of use of self-tests among 25-59 y/o, but not among younger and older age groups. Use of self-tests was highest among 16-24 y/o, people with higher education, lowest population density areas, and people with high overall frequency of testing. Use was lowest among 60+ y/o, unemployed and retired people, and first-generation immigrants. When stratifying by age, 16-24 y/o with high perceived Covid-19 risk were more likely to use self-tests (aOR 1.99, 95% CI 1.10-3.59). Among 25-59 y/o, in-person workers were more likely to use self-tests than remote workers (aOR 1.91 [1.20-3.05]). Among 60+ y/o, employed people were more likely than retired people (aOR 3.97 [2.30-6.85]). Conclusions With higher utilization in low population density areas and among frequent testers, convenience may be a primary driver of use of self-tests. Additional drivers include perceived risk among younger people and exposure at work for those ≥25 yrs. Inequities in use were observed, with lower use among people with low education, older age, and immigrants. Key messages • Use of self-tests in France during the Covid-19 pandemic was low among vulnerable population groups, including people with lower education, immigrants, and older individuals. • Drivers of use included geographical access to healthcare services, perception of risk among younger respondents, and exposure at work among adults aged ≥25 years.

Spatial and seasonal variations of atmospheric microplastics in high and low population density areas at the intersection of tropical and subtropical regions

There is limited information regarding spatial and seasonal variations of atmospheric microplastics (MPs) and factors influencing MPs at the intersection of tropical and subtropical regions. A one-year study was conducted at sites in a high-population-density village (HPDV) and a low-population-density village (LPDV) in Taiwan to investigate the characteristics and influencing factors of airborne MPs. The predominant shapes, sizes, and polymer compositions of MPs were fragments, 3 to 25 and 26–50 μm, and polyamide at both sites. Seasonal variation in MP morphologies was not significant. Average MP concentrations were 2.20 ± 2.97 particles/m3 and 1.92 ± 2.35 particles/m3 at the HPDV and LPDV sites, respectively, and did not differ significantly. Higher concentrations and smaller sizes of MPs were found during the summer at both sites, while the predominant wind direction was southerly or southwesterly. In samples with temperatures exceeding 25 °C, the temperature was positively associated with MP concentrations at both the HPDV and LPDV sites. These results reflect that temperature influences the variations in the concentrations and sizes of MPs at our study site. Future research should consider the adverse risks of MP inhalation during the hot season. Moreover, when sites with different population densities and levels of human activity are closed, MP concentrations will not differ significantly between these areas since airflow can transport these particles from high-population-density areas into low-population-density areas in a short time.

Usability of Community Seismic Network recordings for ground-motion modeling

A source of ground-motion recordings in urban Los Angeles that has seen limited prior application is the Community Seismic Network (CSN), which uses low-cost, micro–electro–mechanical system (MEMS) sensors that are deployed at much higher densities than stations for other networks. We processed CSN data for the 29 earthquakes with M > 4 between July 2012 and January 2023 that produced CSN recordings, including selection of high- and low-pass corner frequencies ( fcHP and fcLP, respectively). Each record was classified as follows: (1) Broadband Record (BBR)—relatively broad usable frequency range from fcHP < 0.5 to fcLP > 10 Hz; (2) Narrowband Record (NBR)—limited usable frequency range relative to those for BBR; and (3) Rejected Record (REJ)—noise-dominated. We compare recordings from proximate (within 3 km) CSN and non-CSN stations (screened to only include cases of similar surface geology and favorable CSN instrument housing). We find similar high- to medium-frequency ground motions (i.e. peak ground acceleration (PGA) and Sa for T < 5 s) from CSN BBR and non-CSN stations, whereas NBRs have lower amplitudes. We examine PGA distributions for BBR and REJ records and find them to be distinguished, on average across the network, at 0.005 g, whereas 0.0015 g was found to be the threshold between usable records (BBR and NBR) and pre-event noise. Recordings with amplitudes near or below these thresholds are generally noise-dominated, reflecting environmental and anthropogenic ground vibrations and instrument noise. We find nominally higher noise levels in areas of high-population density and lower noise levels by a factor of about 1.5 in low-population density areas. By applying the 0.0015 g threshold, limiting distances for the network-average site condition, based on the expected fifth-percentile ground-motion levels, are 89, 210, 280, and 370 km for M 5, 6, 7, and 8 events, respectively.

Contextualised strategies and interventions for ageing in place in low-population density areas

Contextualised strategies and interventions for ageing in place in low-population density areas

Assessment of Solid Waste Management Practices Following Private Partnership Operations in Zaria Urban Area of Kaduna, Nigeria

The safe disposal of municipal waste is very important in promoting a healthy environment. High-quality public services and promoting competition in the waste management sector leads to the formation of private sector participation (PSP) to handle solid waste management in Kaduna. A multi-stage sampling technique was adopted which involves dividing the local government into localities. Stage two involves the purposive sampling technique which was adopted in selecting locality with high population and low population density areas, a total of 400 households from both strata were interviewed. Descriptive statistics was used to analyse the information from the questionnaires and results were presented using frequency tables and charts. The findings revealed that quality of service among the PSP operators recorded high success in the high-income areas and much less in the low and medium-income areas. On average, industry productivity was 5.63 tonnes per day per vehicle. 12 out of which in the study area were above this average and in meeting increased productivity, year of experience in operations, number of trips made, number of times trucks were serviced, and adhering to regulatory agency requirements were among the factors influencing company’s productivity in the state. It also shows less effectiveness of the system in waste management in the area. The study, therefore, recommends that regulatory agency should be more aggressive in playing their statutory roles of managing the PSP operators.

Not only in the crowd: Benthic litter characterization in a low population density area still reveals widespread pollution and local malpractices

Various anthropogenic activities affect marine coastal habitats, leading to heavy litter pollution. However, whilst high litter concentrations are nowadays common in the proximity of metropolises, few studies investigated the magnitude of this phenomenon around coastal villages and small towns. We hereby characterized the benthic litter occurring in the trawlable grounds of the Gulf of Policastro (Tyrrhenian Sea, central-western Mediterranean), a low population density area that becomes a popular tourist destination during summer. We furthermore tested differences between two depths (∼100–200 and ∼500–600 m) and the impact of tourism on the shallower waters. The area was characterized by a litter abundance of 651.12 ± 130.61 item/km2, with plastic being almost totalitarian (93%). The shallower waters hosted two-thirds of the litter found. Almost all (∼95%) the litter items had a land-based origin, while the sea-based litter was mostly found at higher depths. About 14% of the litter was found to be fouled, with the development of litter-associated communities that somehow mimic the natural ones living on hard substrates. The higher litter presence noticed during the touristic peak (July–August) suggests that tourism is an important source of local litter, although it contributed to the local accumulation in a synergic way with other factors. The majority of the litter items presumably originated from the nearby coastline, while the deeper waters were or are used as a dumping site by the local trawling fleet. The discovery of such a critical waste accumulation and management in a somehow remote area contributes to widen the perspectives on the presence of benthic litter mostly in territories characterized by wide anthropization. Moreover, it confirms that appropriate local policies and communication plans are urged even at a regional level to stimulate citizen consciousness and mitigate the ever growing litter pollution.

Open-source data pipeline for street-view images: A case study on community mobility during COVID-19 pandemic.

Street View Images (SVI) are a common source of valuable data for researchers. Researchers have used SVI data for estimating pedestrian volumes, demographic surveillance, and to better understand built and natural environments in cityscapes. However, the most common source of publicly available SVI data is Google Street View. Google Street View images are collected infrequently, making temporal analysis challenging, especially in low population density areas. Our main contribution is the development of an open-source data pipeline for processing 360-degree video recorded from a car-mounted camera. The video data is used to generate SVIs, which then can be used as an input for longitudinal analysis. We demonstrate the use of the pipeline by collecting an SVI dataset over a 38-month longitudinal survey of Seattle, WA, USA during the COVID-19 pandemic. The output of our pipeline is validated through statistical analyses of pedestrian traffic in the images. We confirm known results in the literature and provide new insights into outdoor pedestrian traffic patterns. This study demonstrates the feasibility and value of collecting and using SVI for research purposes beyond what is possible with currently available SVI data. Our methods and dataset represent a first of its kind longitudinal collection and application of SVI data for research purposes. Limitations and future improvements to the data pipeline and case study are also discussed.

Assessing the impact of emergency measures in varied population density areas during a large dengue outbreak

BackgroundThe patterns of dengue are affected by many factors, including population density and climate factors. Densely populated areas could play a role in dengue transmission due to increased human-mosquito contacts, the presence of more diverse and suitable vector habitats and breeding sites, and changes in land use. In addition to population densities, climatic factors such as temperature, relative humidity, and precipitation have been demonstrated to predict dengue patterns. To control dengue, emergency measures should focus on vector management. Most approaches to assessing emergency responses to dengue risks involve applying simulation models or describing emergency activities and the results of implementing those responses. Research using real-world data with analytical methods to evaluate emergency responses to dengue has been limited. This study investigated emergency control measures associated with dengue risks in areas with high and low population densities, considering their different control capacities. MethodologyData from the 2015 dengue outbreak in Kaohsiung City, Taiwan, were utilized. The government database provided information on confirmed dengue cases, emergency control measures, and climatic data. The study employed a distributed lag non-linear model (DLNM) to assess the effect of emergency control measures and their time lags on dengue risk. Principal findingsThe findings revealed that in areas with high population density, the absence of emergency measures significantly elevated the risks of dengue. However, implementing emergency measures, especially a higher number, was associated with lower risks. In contrast, in areas with low population density, the risks of dengue were only significantly elevated at the 1st week lag if no emergency control measures were implemented. When emergency activities were carried out, the risks of dengue significantly decreased only for the 1st week lag. ConclusionsOur findings reveal distinct exposure-lag-response patterns in the associations between emergency control measures and dengue in areas with high and low population density. In regions with a high population density, implementing emergency activities during a significant dengue outbreak is crucial for reducing the risk. Conversely, in areas of low population density, the necessity of applying emergency activities may be less pronounced. The implications of this study on dengue management could provide valuable insights for health authorities dealing with limited resources.

The incidence, and spatial trends of cholera in Sabah over 15 years: Repeated outbreaks in coastal areas.

Vibrio cholerae remains a notable public health challenge across Malaysia. Although the Malaysian state of Sabah is considered a cholera-affected area, gaps remain in understanding the epidemiological trends and spatial distribution of outbreaks. Therefore, to determine longitudinal and spatial trends in cholera cases data were obtained from the Sabah State Health Department for all notified cases of cholera between 2005-2020. A cholera outbreak is defined as one or more confirmed cases in a single locality with the evidence of local transmission. All records were geolocated to village level. Satellite-derived data and generalised linearized models were used to assess potential risk factors, including population density, elevation, and distance to the sea. Spatiotemporal clustering of reported cholera cases and zones of increased cholera risk were evaluated using the tau statistic (τ) at 550m, 5km and 10km distances. Over a 15-year period between 2005-2020, 2865 cholera cases were recorded in Sabah, with a mean incidence rate of 5.6 cases per 100,000 (95% CI: 3.4-7.9). From 2015-2020, 705 symptomatic cases and 727 asymptomatic cases were reported. Symptomatic cases primarily occurred in local Malaysian populations (62.6%, 441/705) and in children and adolescents under 15-years old (49.4%, 348/705). On average, cases were reported in areas with low population density (19.45 persons/km2), low elevations (19.45m) and near coastal areas. Spatiotemporal clustering of cholera cases was identified up to 3.5km, with increased village-level cholera risk within 500m and 5 days of initial case presentation to a health facility (Risk Ratio = 9.7, 95% CI: 7.5-12.4). Cholera incidence has high spatial and temporal heterogeneity within Sabah, with some districts experiencing repeated outbreaks. Cholera cases clustered across space and time, with village-level risk of cholera highest within 5 days and within close proximity to primary case villages, suggesting local transmission.

Continuing Education Needs of Speech-Language Pathologists for Assessing and Treating Children With Cleft Palate: A National Analysis Across Areas of Varying Population Density.

The purpose of this study was to identify training gaps and continuing education (CE) needs for speech-language pathologists (SLPs) in evaluating and treating children with cleft palate across and among areas of varying population density. An anonymous 35-question survey lasting approximately 10-15 min was created in Qualtrics based on a previously published study. The survey information and link were electronically distributed to American Speech-Language-Hearing Association (ASHA)-certified SLPs through ASHA listservs, social media, individual-state SLP organizations, and an e-mail list of publicly listed SLPs. A total of 359 survey responses were collected. Respondents varied in terms of age, type of certification, practice location, and clinical experience with cleft palate, with the largest percentage (46.7%) of respondents in a school-based setting. Only 28.5% reported currently feeling comfortable treating children with cleft palate. Respondents reported conventions/conferences (25.4%) and webinars (23.2%) were the most helpful resources, but DVDs were frequently not used for CE. Information from the child's cleft team (84.4%) and mentors/colleagues (70%) were considered high-quality resources. Respondents indicated information on treatment of articulation (79.2%) and resonance (78.4%) disorders as well as specific therapy techniques (76.9%) would be very helpful for clinical practice. Population density significantly influenced how respondents ranked the perceived helpfulness and quality of different resources as well as desired topics for future resources. There is a continued need for adequate training and CE opportunities for SLPs, particularly related to assessing and treating children with cleft palate. Increased access to high-quality CE resources will be key to filling educational gaps present for SLPs, especially in areas of low-population density. https://doi.org/10.23641/asha.24891423.

Specifics of objectification of the social exclusion, social inclusion categories (territorial aspect) in German

The article deals with specific features of objectification in German related to the categories of social exclusion and social inclusion in the territorial aspect on the example of the concepts «Kaff» and «Einöde». As a result of the definitional analysis of the similar lexemes, denoting these concepts, the author establishes nuclear semantic features – the absence of appropriate social conditions, low-population density area /uninhabited area (Einöde) and its small length, aimlessness of the subject’s existence (Kaff). These notions are described as the semantic field. The study found that the core of the semantic fields of the concepts «Einöde» and «Kaff» are the linguistic units directly indicating the nuclear semantic features and the periphery – the units actualizing the processes of social exclusion and in separate (rare) cases of social inclusion. The author identifies the units expressing spatial remoteness from the center, as well as static, absence of movement, changes as common leading language means expressing the category of social exclusion; as different – the units indicating a small spatial extent, verbs of socially determined movement with certain efforts of the subject (semantic field «Kaff»); verbs of unnoticed, aimless existence of the subject within the given object (semantic field «Einöde»).The results of the research suggest that the lexeme Kaff to a greater extent as compared to the lexeme Einöde objectifies the processes of territorial social exclusion in the context. The author notes that the language units Kaff and Einöde do not have unambiguous equivalents in Russian. As a result of the contextual analysis the author reveals additional semantic features, specifying these concepts, which are not reflected in the glossary of the German language.

Comparing In-Hospital Outcomes for Acute Myocardial Infarction Patients in High-Volume Hospitals Performing Primary Percutaneous Coronary Intervention vs. Regional General Hospitals.

It has been reported that patients with acute myocardial infarction (AMI) transferred to low-volume primary percutaneous coronary intervention (PCI) hospitals (<115/year) in low population density areas experience higher in-hospital mortality rates. This study compared in-hospital outcomes of patients admitted to high-volume primary PCI hospitals (≥115/year) with those for other regional general hospitals. Retrospective analysis was conducted on data obtained from 2,453 patients with AMI admitted to hospitals in Iwate Prefecture (2014-2018). Multivariate analysis revealed that the in-hospital mortality rate of AMI among patients in regional general hospitals was significantly higher than among patients in high-volume hospitals. However, no significant difference in mortality rate was observed among patients with ST-elevation myocardial infarction (STEMI) undergoing primary PCI. Although no significant difference was found in the in-hospital mortality rate of patients with Killip class I STEMI, significantly lower in-hospital mortality rates were observed in patients admitted in high-volume hospitals for Killip classes II, III, and IV. Although in-hospital outcomes for patients with STEMI undergoing primary PCI were similar, patients with heart failure or cardiogenic shock exhibited better in-hospital outcomes in high-volume primary PCI hospitals than those in regional general hospitals.

The effect of population density on outcomes of major trauma patients in Ireland

BackgroundTime-sensitive emergencies in areas of low population density have statistically poorer outcomes. This includes incidents of major trauma. This study assesses the effect that population density at a receiving hospital of a major trauma patient has on survival. MethodsPatients meeting Trauma Audit Research Network criteria for major trauma from 2016 to 2020 in Ireland were included in this retrospective observational study. Incident data were retrieved from the Major Trauma Audit, while data on population density were calculated from Irish state sources. The primary outcome measure of survival to discharge was compared to population density using logistic regression, adjusted for demographic and incident variables. Records were divided into population density tertiles to assess for between-group differences in potential predictor variables. ResultsPopulation density at a receiving hospital had no impact on mortality in Irish major trauma patients from our logistic regression model (OR = 1.01, 95% CI 0.98–1.05, p = 0.53). Factors that did have an impact were age, Charlson Comorbidity Index, Injury Severity Score, and the presence of an Orthopaedic Surgery service at the receiving hospital (all p < 0.001). Age and Charlson Comorbidity Index differed slightly by population density tertile; both were higher in areas of high population density (all p < 0.001). ConclusionsSurvival to discharge in Irish major trauma patients does not differ substantially based on population density. This is an important finding as Ireland moves to a new trauma system, with features based on population distribution. An Orthopaedic Surgery service is an important feature of a major trauma receiving hospital and its presence improves outcomes.

Effects of a volunteer responder system for out-of-hospital cardiac arrest in areas of different population density – A retrospective cohort study

BackgroundVolunteer responder dispatch to nearby out-of-hospital cardiac arrests using a smartphone application can increase the proportion of patients receiving cardiopulmonary resuscitation. It is unknown how population density is related to the efficacy of a volunteer responder system. This study aimed to compare the response time of volunteer responders and EMS dispatched to suspected OHCAs in areas of different population density. MethodsA total of 2630 suspected OHCAs in Stockholm County during 2018–2020 where at least one dispatched volunteer responder reached the patient were identified through the HeartRunner™ application database. Study outcome was the proportion of cases where volunteer responders arrived at the scene before EMS, as well as the difference in time between the arrival of volunteer responders and EMS. ResultsVolunteer responders arrived before EMS in 68% of examined cases (n = 1613). Higher population density was associated with a lower proportion of cases where volunteer responders arrived at the scene before EMS. Time on scene before arrival of EMS was highest in areas of low population density and averaged 4:07 (mm:ss). Response time was significantly shorter for volunteer responders compared to EMS across all population density groups at 4:47 vs 8:11 (mm:ss) (p < 0.001); the largest difference in response time was found in low population density areas. ConclusionVolunteer responders have significantly shorter response time than EMS regardless of population density, with the greatest difference in low population density areas. Although their impact on clinical outcome remains unknown, the benefits of dispatching volunteer responders to OHCAs may be greatest in rural areas.

Domestic water quality and the discriminatory influence of socio-economic stratification on accessibility to safe water in a part of Osun State, Nigeria

The status of the water supplied to households in an urban local government area in southwest Nigeria was examined. Specific objectives were to characterize household water sources, assess the per capita usage of potable water sources and examine quality of the household water in the area. The purposively selected study area, Olorunda local government area in Osun State, Nigeria (being an urban local government area) was stratified into ‘urban core’ (central business district, CBD or high population density area), ‘transition’ (medium population density area but with less social infrastructure) and ‘sub-urban’ (typically government reserved area and low population density area) based on household density and associative socio-economic status. The methods were a mix of questionnaire administration to heads of 120 households (40 per stratum) and collection of the drinking water samples from the supply sources at four randomly selected households in each stratum. The water samples were analysed for the concentrations of nitrite (NO2-), nitrate (NO3-), fluoride (F-), lead (Pb) and arsenic (As) as well as E-coli bacteria contents based on their importance in determining water quality in urban areas. The results showed that domestic water sources are mainly hand dug well (55.8%), borehole (37.5%) and pipe borne (6.7%). Residents averagely consumed at most 4L of water per day. Furthermore, the investigated chemical parameters varied as NO2 (0.37-0.94 mg/l), NO3 (0.29-0.70 mg/l), and F- (0.003-0.97 mg/l). As and Pb occurred in trace quantities, and there were no pollution threats to consumers. The amount of E coli and total coliform contents were however outside the safe limits for residents, suggesting contamination of household water by the bacteria sources. The study concluded communities with low socio-economic status which do not have access to state-provided tap water source are more likely to consume polluted water than those with high socio-economic status or that are supplied with state-provided tap water. The study advocates improve urban water management for the urban fringe dwellers.

Analysis of cycling network evolution in OpenStreetMap through a data quality prism

Abstract. Cycling practice has been constantly increasing for several years and the COVID crisis has just accelerated the process. Indeed, more and more municipalities have developed new cycle paths to facilitate cycling. Considering this increasing interest for cycling, it makes sense to study how this recent evolution is reflected in the underlying representation of the cycling network in the geographic databases. Main studies analysing the evolution of the road network focus on the motor vehicle network in the major cities of the world. These studies do not seem applicable to cycling network specially to some low population density areas or even to smaller cities. This paper analyses the changes in the cycling network through OSM data from a data freshness perspective. These changes can be either updates from changes in the real-world network or upgrades to the network. To these end, we propose a method using a Monte Carlo simulation (MCS) to analyse the frequency of changes in cycling routes in several areas with different population density, all in the Loire Valley region in France. We also define the cycling network, which is a very complex concept and we explain how it is represented in OSM data and suffers from different data quality issues. Results show that the number of changes across time are similar in areas having a similar population density, while being lower in low population density areas. These phenomena is higher in the cycling network compared to other networks.

Demotorization and Space: The Influence of Spatial Factors on Car-Dependency Reduction in France

Although car ownership continues to rise worldwide, temporary or more lasting phases of demotorization (reduction in the number of vehicles owned) are taking place at the household level. Existing studies show that the probability of demotorization increases at certain stages of the life cycle, for example, associated with a reduction in household size or income, or a move to a neighborhood with better transit provision. However, the rationale and temporalities of the decision-making processes involved remain obscure. This knowledge could be useful in informing public action on the measures needed in different categories of territories and populations to encourage a steady and sustainable fall in car ownership. As its contribution to these questions, this article focuses on the influence of spatial factors on household demotorization. The methodology draws on 51 interviews conducted in 2018 with demotorized households in four French urban areas (Paris, Lyon, Bordeaux, and Dijon). The findings highlight the role of the characteristics of the current place of residence, changes in the place of residence or place of work, and the spatial dimensions of travel socialization. If, as things stand, permanent and voluntary relinquishment of the car is only possible in very dense urban areas, our results show firstly that there is a strong case for working on mobility representations and practices from a very early age and, secondly, the importance of implementing planning policies and alternatives to the private car that are credible in areas of lower population density.

Occurrence Characteristics of Microplastics and Metal Elements in the Surface Water of Huangpu River and Their Associations with Metal Resistance Genes

Urban rivers have been regarded as the "hotspots" for microplastic (MPs) and metal contamination as they play important roles in pollution migration. However, as important sinks and sources of resistance genes, there has been little to no research investigating the associations between MPs, metal contaminations, and metal resistance genes (MRGs). Ten water samples were collected from the Huangpu River in situ; along with metal elements, MPs characteristics analyzed. Metal resistance genes and mobile genetic elements (MGEs) in waters and MPs were detected using metagenomic technology. As a result, the highest metal concentration was that of Sb in surface water (3.16±0.419) μg·L-1. The average abundance of MPs was (1.78±0.84) n·L-1, and the peak levels located in industrial and densely populated areas, which was significantly higher than those in agricultural and low population density areas. Fibrous, small-size (<0.5 mm), and transparent polyethylene terephthalate (PET) were the largest contributors of MPs. Eighteen MRGs were detected in all the samples. The relative abundance of MRGs in water was 1.68±0.21. The most dominant MRGs subtypes were merR and ruvB, which are subtypes resistant to mercury and Multi_metals. Correlation analysis showed that chromium and nickel in waters were significantly positively associated with MRG-Cr, MRG-Ni, and Multi_metals resistance genes. For MPs particles, the relative abundance of MRGs was 1.63±0.53. The most dominant MRGs subtypes were merT-P and copB, which also belong to mercury-resistant and Multi_metals. The Multi_metals resistance gene, ctpC, cueA, czrA, kmtR, etc., had significant positive associations with Ni, Cr, and Sb in waters. Compared with water samples, MPs selectively enriched merT-P, copB, ziaA, sodA, and dmeF. Additionally, the co-occurrence patterns of MRGs and MGEs were explored based on network analysis. In water samples, the transposases (tnpA_1 and tnpA_2), integrase (qacEdelta), and insertion sequence (IS91) were the major contributors of the horizontal gene transfer (HGT) of specific MRGs. Multiple subtypes resistant to copper and Multi_metals resistance genes on MPs were positively associated with IncFIC(FII), Rep7, rep7, and rep13, which were subtypes of plasmids. The presence of MPs exerted a significant impact on HGT of specific MRGs mediated by plasmids.

Unmatched spatially stratified controls: A simulation study examining efficiency and precision using spatially-diverse controls and generalized additive models

Unmatched spatially stratified random sampling (SSRS) of non-cases selects geographically balanced controls by dividing the study area into spatial strata and randomly selecting controls from all non-cases within each stratum. The performance of SSRS control selection was evaluated in a case study spatial analysis of preterm birth in Massachusetts. In a simulation study, we fit generalized additive models using controls selected by SSRS or simple random sample (SRS) designs. We compared mean squared error (MSE), bias, relative efficiency (RE), and statistically significant map results to the model results with all non-cases. SSRS designs had lower average MSE (0.0042–0.0044) and higher RE (77–80%) compared to SRS designs (MSE: 0.0072–0.0073; RE across designs: 71%). SSRS map results were more consistent across simulations, reliably identifying statistically significant areas. SSRS designs improved efficiency by selecting controls that are geographically distributed, particularly from low population density areas, and may be more appropriate for spatial analyses.