Stratified Sampling Design Research Articles

Demography of baobab (Adansonia digitata L.) population in different land uses in the semi-arid areas of Tanzania

Baobab is a deciduous non-timber tree species that are facing severe threats from both anthropogenic and climatic pressures across its range states. This study assessed natural rates of recruitment and associated threats of baobabs within and across different land-use types in semi-arid areas of Tanzania. The study was based on a stratified random sampling design composed of the following land-use types: strictly protected areas, non-strictly protected areas, and unprotected areas. Rates of recruitment were measured from a total of 337 grids (representing 40% of semi-arid land) in three different land-use types in a plot measuring 1 km long and 50 m wide. Results show that juvenile, sub-adult and adult baobab populations varied significantly (p < 0.001) within and across land-use types with only 4.7% of surveyed plots having a few juveniles (about four stems per plot) across the study area. The density of adult, sub-adult and juvenile populations were 1.53 ± 0.105, 0.82 ± 0.149 and 0.33 ± 0.253 plants/ha respectively with strictly protected areas (national parks) supporting the most abundant (53%) of the adult trees. Furthermore, the results show inverse J-shaped and bell-shaped distribution in the strictly protected areas and unprotected areas, respectively. The densities of mature baobabs were found to be higher than juvenile baobabs in all three land-use types. The number of baobabs damaged was higher than undamaged in all land-use types. Our results suggest that anthropogenic threats are higher than biophysical factors in driving the species to mortality and population extirpation. Likely, baobab size and distribution across land-use types are mostly influenced by herbivory and fire that likely limit the establishment in most of these areas. Strategies promoting the recruitment and sustainable harvesting practices of baobab would perhaps be the best options to support the population persistence in different land uses in semi-arid areas. The study recommends more studies to understand the factors affecting germination and recruitment rates in order to predict future distributions in semi-arid environments. Also in defining and planning for different land-use system, baobab species should be taken into consideration and in particular in agroforestry farms can easily qualify as a tree crop. Promotion of active recruitment through planting especially in communal lands and protection from herbivory is required if we are to overcome the recruitment bottlenecks as influenced by increasing impacts of land use and climate change and overexploitation. The intentional growing of trees and shrubs in combination with crops cultivation and forage production is also recommended to smallholder farmers.

Associated factors of willingness to undergo routine chlamydia trachomatis screening among hospital-based patients in Shenzhen, China: a cross-sectional study

BackgroundChlamydia trachomatis (CT) is a common sexually transmitted infection (STI) with significant morbidity. The study aimed to explore the willingness to undergo routine CT screening and its associated factors among hospital-based patients in Shenzhen.MethodsWe used data from the Shenzhen Gonorrhea and Chlamydia Intervention Programme. Participants were recruited with a stratified purposeful sampling design from 1 April 2018 to 16 May 2018. A structured questionnaire was used to obtain data on baseline characteristics and CT-related participant information.ResultsOf the 16,546 participants, 64.79% were women, with a mean age of 31.85 ± 7.31 of all participants. Of the participants, 88.78% were willing to undergo routine CT screening. According to multivariate logistic regression analyses, willingness to undergo routine CT screening was associated with the following (P < 0.05): being a woman (AOR = 1.53, 95% CI = 1.34–1.75), one year or more residency in Shenzhen (AOR = 1.64, 95% CI = 1.37–1.95), any secondary education (AOR = 2.46, 95% CI = 1.92–3.15), monthly income ≥ RMB 10,000 (AOR = 1.24, 95% CI = 1.01–1.51), having forgotten CT diagnosis history (AOR = 1.42, 95% CI = 1.12–1.79), without current STI-related symptoms (AOR = 1.24, 95% CI = 1.10–1.41), and having correct understanding of the sequelae of CT infection (AOR = 1.68, 95% CI = 1.39–2.03).ConclusionThis study reported high willingness to undergo routine CT screening among hospital-based patients in Shenzhen, and provided evidence for the promotion and the implementation of strategies and recommendations on routine CT screening in China.

Oral rehydration solution coverage in under 5 children with diarrhea: a tri-country, subnational, cross-sectional comparative analysis of two demographic health surveys cycles

BackgroundMore than 3 million children under 5 years in developing countries die from dehydration due to diarrhea, a preventable and treatable disease. We conducted a comparative analysis of two Demographic Health Survey (DHS) cycles to examine changes in ORS coverage in Zimbabwe, Zambia and Malawi. These surveys are cross-sectional conducted on a representative sample of the non-institutionalized individuals.MethodsThe sample is drawn using a stratified two-stage cluster sampling design with census enumeration areas, typically, selected first as primary sampling units (PSUs) and then a fixed number of households from each PSU. We examined national and sub-regional prevalence of ORS use during a recent episode of diarrhea (within 2 weeks of survey) using DHSs for 2007–2010 (1st Period), and 2013–2016 (2nd Period). Weighted proportions of ORS were obtained and multivariable- design-adjusted logistic regression analysis was used to obtain Odds Ratios (aORs) and 95% confidence intervals (CIs) and weighted proportions of ORS coverage.ResultsCrude ORS coverage increased from 21.0% (95% CI: 17.4–24.9) in 1st Period to 40.5% (36.5–44.6) in 2nd Period in Zimbabwe; increased from 60.8% (56.1–65.3) to 64.7% (61.8–67.5) in Zambia; and decreased from 72.3% (68.4–75.9) to 64.6% (60.9–68.1) in Malawi. The rates of change in coverage among provinces in Zimbabwe ranged from 10.3% over the three cycles (approximately 10 years) in Midlands to 44.2% in Matabeleland South; in Zambia from − 9.5% in Eastern Province to 24.4% in Luapula; and in Malawi from − 16.5% in the Northern Province to − 3.2% in Southern Province. The aORs for ORS use was 3.95(2.66–5.86) for Zimbabwe, 2.83 (2.35–3.40) for Zambia, and, 0.71(0.59–0.87) for Malawi.ConclusionORS coverage increased in Zimbabwe, stagnated in Zambia, but declined in Malawi. Monitoring national and province-level trends of ORS use illuminates geographic inequalities and helps identify priority areas for targeting resource allocation.. Provision of safe drinking-water, adequate sanitation and hygiene will help reduce the causes and the incidence of diarrhea. Health policies to strengthen access to appropriate treatments such as vaccines for rotavirus and cholera and promoting use of ORS to reduce the burden of diarrhea should be developed and implemented.

Non‐random sampling along rural–urban gradients may reduce reliability of multi‐species farmland bird indicators and their trends

The continued global biodiversity crisis necessitates the continuation and development of new well‐designed monitoring strategies and action plans with particular focus on under‐represented countries and regions. However, limited resources in terms of budget and availability of qualified field personnel can restrict the geographical coverage of monitoring efforts. Focusing monitoring efforts on a representative subset of species and locations can improve cost‐efficiency. Optimal performance of multi‐species indicators derived from such an approach requires objective methods for species selection and a sampling design that reduces inherent sampling bias caused by regional differences in habitat availability or accessibility. To explore the performance of a multi‐species indicator across different regions within a nation, we developed a multi‐species indicator (MSI) for farmland birds in Norway using objective niche‐based selection of species. We compare the performance of this indicator at national and regional scales (Central and East regions) in Norway, and between urban and rural sites within regions. The seven‐species indicator obtained from the species selection provided similar indicator values and trends for Norway and the Central and East regions, as well as for rural sites within the combined Central + East region. All trends were defined as showing moderate decline from 2007–2016. Urban sites within the combined Central + East region provided trend estimates that showed stronger decline than rural areas in the same region during the time span. Our results emphasize the need to control for sampling bias when structuring monitoring programmes such as a Breeding Bird Survey (BBS). This is especially important if limited resources restrict the geographical coverage of the monitoring scheme. We recommend that monitoring schemes follow a stratified random sampling design that represents both the availability of different land cover types and their distribution with regard to proximity to highly populated areas. If that is not possible, statistically weighting data from different regions or landscapes is likely to be necessary.

The importance of riparian forests and tree plantations for the occurrence of the European Turtle DoveStreptopelia turturin an intensively cultivated agroecosystem

SummaryFarmland birds represent a large proportion of European avifauna, and the populations of several species have suffered a dramatic decline in recent decades. Among these species, the European Turtle DoveStreptopelia turturhas undergone rapid decline in much of its European range. Therefore, the main aims of this research are to estimate the population density of the Turtle Dove and to investigate its habitat use at home range scale in an intensively cultivated agroecosystem in northern Italy. In the 2015 breeding season we carried out turtle dove counts from 372 point-counts, randomly allocated following a stratified cluster sampling design. The density was estimated by distance sampling, whereas the habitat suitability was assessed by Resource Selection Probability Function. In particular, we followed a presencevsavailability approach, using binary logistic regression and the Information-Theoretic approach. During fieldwork, 76 observations of Turtle Dove were collected and a density of 5.0 pairs/km2was estimated. The Turtle Dove inhabits areas with high tree cover, either semi-natural forests or tree plantations, as well as areas with many shrubs and hedgerows. On the other hand, areas with a high proportion of crops, such as paddyfields, maize, and winter cereals are avoided. For the species’ conservation, it is necessary to maintain a combination of habitat features with suitable nesting and feeding areas, as the degradation of either of these may reduce Turtle Dove populations.

Small fires, frequent clouds, rugged terrain and no training data: a methodology to reconstruct fire history in complex landscapes

An automated burned area extraction routine that attempts to overcome the particular difficulties of remote sensing applications in complex landscapes is presented and tested in the mountainous region of northwest Yunnan, China. In particular, the lack of burned samples to use for training and testing, the rugged relief, the small size of fires and the constant presence of clouds during the rainy season heavily affecting the number of usable scenes within a year are addressed. The algorithm flows through five phases: creation of standardised difference vegetation indices time series; automatic extraction of multiclass training areas using adaptive z-score thresholds; Random Forests classification; Seeded Region Growing; and spatiotemporal clustering to form polygons representing fire events. A final database spanning the period 1987–2018 was created. Accuracy assessment of location and number of fire polygons using a stratified random sampling design showed satisfactory results with reduced omission and commission errors compared with global fire products in the same region (20 and 22% respectively). Mapping accuracy of single burned areas showed higher omission (27%) but reduced commission (13%) errors. This methodology takes a step forward towards the inclusion of regions characterised by small fires that are often poorly represented in impact assessments at the global scale.

An evaluation of observer monitoring program designs for Chinese tuna longline fisheries in the Pacific Ocean using computer simulations.

This paper evaluates the performance of different observer coverage rates and 9 possible sampling designs to estimate via computer simulation the total catch of target and non-target species for Chinese tuna longline fisheries in the Pacific Ocean. The stratified random samplings include different stratification schemes (based on target species or fishing areas) with different strategies for allocating observers. The observer data from 103 vessels between 2010 and 2019 were assumed to be the "true" sampling population. We concluded that the accuracy of catch estimates had a significant positive relationship with species detectability and observer coverage rate. On average, the accuracy improved by 50% when the coverage rate increases from 5 to 20%. Current simple random sampling in Chinese tuna longline fisheries is less efficient for monitoring many species. Stratified sampling designs based on the target species tended to yield the most accurate estimates of the total catch. Allocating the observers based on the scale of the fleets in different stratum seemed to be less efficient. The proportion of observers between different fleets should be adjusted according to different monitoring objectives. In general, a large proportion of observers are recommended to be allocated onboard vessels targeting bigeye tuna (Thunnus obesus). This study has the potential to have a significant contribution to future designs of the observer monitoring programs in Chinese tuna longline fishery and many other fisheries.

Quantification of farm mechanization status in Kanker district of Chhattisgarh, India

Investigation on farm mechanization status of Kanker district Chhattisgarh was carried out for sustainable crop production. District falls in Chhattisgarh plains and Bastar plateau of agro climatic zones of Chhattisgarh having average rainfall varies from 1400 mm to 1500 mm where 90 % rainfall during the June to October. The total net sown area of the district is 2.37 lakh ha with cropping intensity around 122 %. To known the status of farm mechanization, level of mechanization was found out by considering available farm power sources namely human, animal and mechanical. A stratified multistage sampling design was applied considering block as a first stage, village as a second stage and cultivators are the final stage of the sampling. From Kanker district of Chhattisgarh. The 30 villages were selected from each seven block of Kanker district using Probability Proportional to Size (of Village). Then from each village, 10 cultivators were selected using random sampling. Primary data were collected from 300 cultivators from 30 villages. After selection of variables, a standard questionnaire was prepared to collect primary data. Average value of power availability, farm power consumption and present mechanization level is significantly highest in high productive blocks namely Charama, Kanker, Koilibeda in comparison to other four low productive blocks i.e. Antagarh, Bhanupratappur, Durgkondal and Narharpur block, respectively. Draft animal power available in study area was 0.41 bullock-pair per ha. The command area available per unit of power source for the marginal, small, medium and large farmers was 0.70, 2.01, 3.50 and 11.33 ha/bullock pair with over all availability of 2.42 ha per bullock-pair. However, tractor and power tiller manage the overall command area of 40.43 ha per tractor and 165.38 ha per power tiller. The mechanization level of Kanker district was found 1.37 kW ha-1.

The impact of the plateau pika on the relationship between plant aboveground biomass and plant species richness

AbstractHerbivores can influence plant species richness and plant aboveground biomass. However, only a few studies have examined their impact on the relationship between plant aboveground biomass and plant species richness, focusing on large herbivores. This study examined the influence of a small burrowing herbivore, the plateau pika (Ochotona curzoniae) with averaging 150 g, on the plant aboveground biomass, plant species richness, and their relationship in the alpine meadows on the Qinghai–Tibet Plateau. The study used a random stratified paired sampling design to collect data on plant species richness and plant aboveground biomass across five sites. Each site contained 10 pairs of plots. Each pair consisted of an undisturbed plot and a disturbed plot. Plant species richness was higher in the disturbed plots; whereas, plant aboveground biomass did not differ in relation to plateau pika disturbance. In the undisturbed plots, the plant species richness increased positively with plant aboveground biomass. In the disturbed plots, the plant species richness peaked at intermediate plant aboveground biomass levels. The findings suggest that small herbivores could alter the relationship between plant aboveground biomass and plant species richness by inducing an increase in plant species diversity, and they should be considered for assessing the management and conservation measures of alpine meadow.

A comparison of abundance and distribution model outputs using camera traps and sign surveys for feral pigs

Species distribution models play a central role in informing wildlife management. For models to be useful, they must be based on data that best represent the presence or abundance of the species. Data used as inputs in the development of these models can be obtained through numerous methods, each subject to different biases and limitations but, to date, few studies have examined whether these biases result in different predictive spatial models, potentially influencing conservation decisions. In this study, we compare distribution model predictions of feral pig (Sus scrofa) relative abundance using the two most common monitoring methods: detections from camera traps and visual surveys of pig sign. These data were collected during the same period using standardised methods at survey sites generated using a random stratified sampling design. We found that although site-level observed sign data were only loosely correlated with observed camera detections (R2=0.32–0.45), predicted sign and camera counts from zero-inflated models were well correlated (R2=0.78–0.88). In this study we show one example in which fitting two different forms of abundance data using environmental covariates explains most of the variance between datasets. We conclude that, as long as outputs are produced through appropriate modelling techniques, these two common methods of obtaining abundance data may be used interchangeably to produce comparable distribution maps for decision-making purposes. However, for monitoring purposes, sign and camera trap data may not be used interchangeably at the site level.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): Usage and co-prescription with other potentially interacting drugs in elderly: A cross-sectional study.

Globally, usage of non-steroidal anti-inflammatory drugs (NSAIDs) in elderly with chronic pain has been reported as frequent. Though NSAIDs are fundamental in maintaining their quality of life, the risk of polypharmacy, drug interactions and adverse effects is of paramount importance as the elderly usually require multiple medications for their co-morbidities. If prescriptions are not appropriately monitored and managed, they are likely to expose patients to serious drug interactions and potentially fatal adverse effects. This study was conducted to assess the appropriateness of NSAIDs use and determine the risk of NSAIDs related potential interactions in elderly. An analytical cross-sectional study was conducted among elderly out-patients (aged 60 and above) who visited three hospitals in Asmara, Eritrea, between August 22 and September 29, 2018. A stratified random sampling design was employed and data was collected using an interview-based questionnaire and by abstracting information from patients' prescriptions and medical cards. Descriptive and analytical statistics including chi-square test and logistic regression were employed using IBM SPSS (version 22). A total of 285 respondents were enrolled in the study with similar male to female ratio. One in four of all respondents were chronic NSAIDs users and NSAIDs risk practice was reported in 24%. Using chronic NSAIDs without prophylactic gastro-protective agents, self-medication, polypharmacy and drug-drug interactions were the main problems identified. A total of 322 potential interactions in 205 patients were identified and of which, 97.2% were classified as moderate, 0.6% severe and the rest were mild. Those who involved in self-medication were more likely to be exposed to drug interactions. Diabetes (AOR = 2.39, 95% CI: 1.14, 5.02) and hypertension (AOR = 9.06, 95% CI: 4.00, 20.51) were associated with chronic NSAIDs use and incidence of potential drug interactions (AOR = 3.5, 95%CI: 1.68, 4.3; AOR = 2.81, 95%CI: 1.61, 4.9 respectively), while diabetes AOR = 4.5, 95% CI: 2.43, 8.35) and cardiac problems (AOR = 4.29, 95% CI: 1.17, 15.73) were more likely to be associated with incidence of polypharmacy. In conclusion, chronic use of NSAIDs without gastro-protective agents and therapeutic duplication of NSAIDs were commonly which requires attention from programmers, health facility managers and healthcare professionals to safeguard elderlies from preventable harm.

Associations of Mental Health and Personal Preventive Measure Compliance With Exposure to COVID-19 Information During Work Resumption Following the COVID-19 Outbreak in China: Cross-Sectional Survey Study.

BackgroundRisk and crisis communication plays an essential role in public health emergency responses. The COVID-19 pandemic has triggered spontaneous and intensive media attention, which has affected people’s adoption of personal preventive measures and their mental health.ObjectiveThe aim of this study was to investigate the associations between exposure to COVID-19–specific information and mental health (depression and sleep quality) and self-reported compliance with personal preventive measures (face mask wearing and hand sanitizing). We also tested whether these associations were moderated by thoughtful consideration of the veracity of the information to which people were exposed.MethodsA cross-sectional, closed web-based survey was conducted among a sample of 3035 factory workers at the beginning of work resumption following the COVID-19 outbreak in Shenzhen, China. A stratified two-stage cluster sampling design was used for recruitment. Multivariate linear and logistic regression models were used for the analyses.ResultsThe prevalence of probable moderate-to-severe depression was 170/3035 (5.6%), while that of good or excellent sleep quality was 2110/3035 (69.5%). The prevalence of self-reported consistent face mask wearing in public places was 2903/3035 (95.7%), while that of sanitizing hands every time after returning from public spaces or touching public installations was 2151/3035 (70.9%). Of the 3035 respondents, 1013 to 1638 (33.3% to 54.0%) reported >1 hour of daily exposure to COVID-19–specific information through web-based media and television. After controlling for significant background variables, higher information exposure via television and via newspapers and magazines was associated with better sleep quality and higher compliance with hand sanitizing. Higher exposure via unofficial web-based media was associated with higher compliance with hand sanitizing but was also associated with higher depressive symptoms. In contrast, higher exposure through face-to-face communication was associated with higher depressive symptoms, worse sleep quality, and lower compliance with hand sanitizing. Exposure to information about positive outcomes for patients with COVID-19, development of vaccines and effective treatments, and heroic stories about frontline health care workers were associated with both better mental health and higher compliance with preventive measures. Higher overall information exposure was associated with higher depressive symptoms among participants who were less likely to carefully consider the veracity of the information to which they were exposed; it was also associated with better sleep quality among people who reported more thoughtful consideration of information veracity.ConclusionsThis study provides empirical evidence of how the amount, sources, and contents of information to which people were exposed influenced their mental health and compliance with personal preventive measures at the initial phase of work resumption in China. Thoughtful consideration of information quality was found to play an important moderating role. Our findings may inform strategic risk communication by government and public health authorities during the COVID-19 pandemic.

Trade-off assessments between reading cost and accuracy measures for digital camera monitoring of recreational boating effort

Digital camera monitoring is increasingly being used to monitor recreational fisheries. The manual interpretation of video imagery can be costly and time consuming. In an a posteriori analysis, we investigated trade-offs between the reading cost and accuracy measures of estimates of boat retrievals obtained at various sampling proportions for low, moderate and high traffic boat ramps in Western Australia. Simple random sampling, systematic sampling and stratified sampling designs with proportional and weighted allocation were evaluated to assess trade-offs in terms of bias, accuracy, precision, coverage rate and cost in estimating the annual total number of powerboat retrievals in 10,000 jackknife resampling draws. The relative standard error (RSE ± standard deviations) obtained by the sampling designs for sampling proportions from 0.4 onwards were below a 20 % threshold for three of the sampling designs across the three boat ramps. Coverage rates of over 90 % were observed for the confidence intervals for the estimated annual number of powerboat retrievals, with low relative standard errors (RSE < 20 %). Interpreting 40 % of camera footage within a year provided the minimum level to obtain sufficient accuracy measures for all sampling designs considered. The stratified random sampling design with weighted allocation consistently resulted in the smallest variance for estimates of annual powerboat retrievals across the various sampled proportions. These findings have the potential to considerably reduce the cost of manual data interpretation, since operating cost increased linearly with increasing sampling proportion.

Community isolation drives lower fish biomass and species richness, but higher functional evenness, in a river metacommunity

Abstract The flow of individuals among communities and their interactions with local environmental filters are increasingly recognised as determinants of biodiversity patterns in riverine ecosystems. Both incoming dispersers and local conditions are expected to systematically change along connectivity gradients from headwaters to downstream communities. However, the interplay between isolation‐centrality gradients and environmental conditions as determinants of biodiversity structure and function has seldom been considered. Here, we represented the dendritic structure of the Negro River basin riverscape (Uruguay) in a directed graph quantifying the isolation‐centrality of each river section and evaluated the direct and indirect pathways by which riverscape structure and environmental local drivers determine fish community assembly. Fish communities (n = 58) were sampled following a stratified sampling design that properly represents this isolation‐centrality connectivity gradient through the riverscape. In each community, fish abundance, biomass, richness, and functional diversity were estimated, and the direct and indirect hypothesised connections among them were evaluated with structural equation models. We showed that the range of isolation among river sections determines a 2‐fold, 5‐fold, and 25‐fold variation in total fish richness, abundance, and biomass, respectively. Additionally, isolation‐centrality was positively associated with local temperature and conductivity, while negatively related to local depth. These variables and taxonomic richness accounted for most of the variation in total fish biomass (81%) herein used as measurement of ecosystem function. Local fish abundance was negatively and positively associated with functional evenness and taxonomic richness, respectively. Furthermore, once the effect of isolation on biomass and richness was accounted for, an effect of diversity on biomass became evident. Our results provide empirical evidence for the role of riverscape structure on taxonomic and functional diversity, biomass, and the relationship between biodiversity and ecosystem function. We emphasise that in the understanding of river biodiversity and its management, local determinants should not be considered without attention to metacommunity processes.

Self-Reported Compliance With Personal Preventive Measures Among Chinese Factory Workers at the Beginning of Work Resumption Following the COVID-19 Outbreak: Cross-Sectional Survey Study.

BackgroundMaintaining compliance with personal preventive measures is important to achieve a balance of COVID-19 pandemic control and work resumption.ObjectiveThe aim of this study was to investigate self-reported compliance with four personal measures to prevent COVID-19 among a sample of factory workers in Shenzhen, China, at the beginning of work resumption in China following the COVID-19 outbreak. These preventive measures included consistent wearing of face masks in public spaces (the workplace and other public settings); sanitizing hands using soap, liquid soap, or alcohol-based hand sanitizer after returning from public spaces or touching public installations and equipment; avoiding social and meal gatherings; and avoiding crowded places.MethodsThe participants were adult factory workers who had resumed work in Shenzhen, China. A stratified two-stage cluster sampling design was used. We randomly selected 14 factories that had resumed work. All full-time employees aged ≥18 years who had resumed work in these factories were invited to complete a web-based survey. Out of 4158 workers who had resumed work in these factories, 3035 (73.0%) completed the web-based survey from March 1 to 14, 2020. Multilevel logistic regression models were fitted.ResultsAmong the 3035 participants, 2938 (96.8%) and 2996 (98.7%) reported always wearing a face mask in the workplace and in other public settings, respectively, in the past month. However, frequencies of self-reported sanitizing hands (2152/3035, 70.9%), avoiding social and meal gatherings (2225/3035, 73.3%), and avoiding crowded places (1997/3035, 65.8%) were relatively low. At the individual level, knowledge about COVID-19 (adjusted odds ratios [AORs] from 1.16, CI 1.10-1.24, to 1.29, CI 1.21-1.37), perceived risk (AORs from 0.58, CI 0.50-0.68, to 0.85, CI 0.72-0.99) and severity (AOR 1.05, CI 1.01-1.09, and AOR 1.07, CI 1.03-1.11) of COVID-19, perceived effectiveness of preventive measures by the individual (AORs from 1.05, CI 1.00-1.10, to 1.09, CI 1.04-1.13), organization (AOR 1.30, CI 1.20-1.41), and government (AORs from 1.14, CI 1.04-1.25, to 1.21, CI 1.02-1.42), perceived preparedness for a potential outbreak after work resumption (AORs from 1.10, CI 1.00-1.21, to 1.50, CI 1.36-1.64), and depressive symptoms (AORs from 0.93, CI 0.91-0.94, to 0.96, CI 0.92-0.99) were associated with self-reported compliance with at least one personal preventive measure. At the interpersonal level, exposure to COVID-19–specific information through official media channels (AOR 1.08, CI 1.04-1.11) and face-to-face communication (AOR 0.90, CI 0.83-0.98) were associated with self-reported sanitizing of hands. The number of preventive measures implemented in the workplace was positively associated with self-reported compliance with all four preventive measures (AORs from 1.30, CI 1.08-1.57, to 1.63, CI 1.45-1.84).ConclusionsMeasures are needed to strengthen hand hygiene and physical distancing among factory workers to reduce transmission following work resumption. Future programs in workplaces should address these factors at multiple levels.

The effect of environmental change on sustainable energy in Olkaria geothermal and Kenya power station, Nakuru County, Kenya

Energy is one of the most important resources in the growth of an economy. The generation of power is key to the effectiveness of sustainable energy management. Energy production warrants production hence connected to economic development. Environmental change has an impact on the sustainability of renewable energy. The objective of this study was to analyze the effect of environmental change on sustainable energy in Olkaria Geothermal and Kenya Power Station, Nakuru County, Kenya. The study was informed by two theories namely; Socio-technical Transitions Approach Theory and Co-evolutionary Approach to Transitions. The study adopted a descriptive research design. The target population was 359 employees with a stratified sample design. The sample frame was 108 employees being 30% of the total population. Data were analyzed using the Statistical Package for Social Science (SPSS). The preliminary data was analyzed using descriptive statistics and presented in the form of tables. Inferential statistics were employed through Pearson’s Correlation analysis and regression analysis was used to test the study hypothesis at a 5% significance level. The findings indicated that was a statistically significant relationship between environmental change and sustainable energy (r=0.286; p=0.005). Further, the study revealed that environmental change has a statistically significant effect on sustainable energy in Olkaria Geothermal and Kenya Power Station, Nakuru County, Kenya (p&lt;0.05). The study recommends that institutional environmental changes should be examined and their influence on sustainable energy management.

Prevalence and factors associated with antenatal care utilization in Ethiopia: an evidence from demographic health survey 2016

BackgroundEthiopia is one of the sub-Saharan African country with high maternal mortality ratio (MMR). According to Ethiopian demographic health survey (EDHS) 2016 report, MMR is 420 among 100,000 live births. Antenatal care utilization is a key intervention to reduce these deaths through problem detection and treatment, promotion of health seeking behavior, and preparing pregnant women for birth. Therefore, this study aimed to assess prevalence and factors associated with antenatal care service utilization in Ethiopia in 2016.MethodsSecondary data analysis was done on EDHS 2016. It was a stratified, two-stage, and cluster sampling design. Analysis has been restricted to antenatal care utilization among women who delivered at least one time in the past five years. Data were weighted to correct sampling bias. Moreover, complex data analysis was done. Bi-variate and multivariable logistic regression analyses were carried out. Adjusted odds ratio with 95% confidence interval was computed and P-value less than 0.05 considered as a statistically significance level for identification of association.ResultsPrevalence of antenatal care utilization was 62.8% [95%CI: 60.9, 64.6] in this study. Maternal educational status of primary school (AOR = 1.8,95%CI:1.2, 2.6), maternal educational status of secondary school (AOR = 4.4,95%CI: 1.1, 17.3), women who listen radio less than 1 per week (AOR = 1.9,95%CI:1.12,3.34), women who listen radio at least 1 per week (AOR = 2.6,95%CI:1.4,4.8), women in rich wealth quintile (AOR = 1.9,95%CI: 1.1, 3.2) were factors positively associated with antenatal care utilization. However, women who had traditional belief (AOR = 0.1,95%CI:0.02,0.49), and women who had five children and above (AOR = 0.6,95%CI: 0.3, 0.9) were factors associated negatively with antenatal care utilization.ConclusionsPrevalence of antenatal care utilization is still low in Ethiopia in 2016. Maternal higher maternal educational status, frequent radio listening, higher wealth quintile, traditional belief, and greater number of children were found to be associated significantly with antenatal care utilization. Consequently, socio-economic status should be enhanced, information should be accessed by women about antenatal care utilization and family planning service through mass media. Furthermore, intensive community education program should be designed for traditional believers to increase uptake of antenatal care by stakeholders.

Prevalence of obesity and its associated risk factors among the elderly in Malaysia: Findings from The National Health and Morbidity Survey (NHMS) 2015.

BackgroundObesity is a crucial public health problem and is rising globally. This study was conducted to determine the prevalence of obesity and its associated factors among the elderly in Malaysia.MethodsData were obtained from the National Health and Morbidity Survey (NHMS) 2015. This was a cross sectional population-based study using a two stage stratified random sampling design. Elderly population aged 60 years and above was selected. Data were collected using pre-tested self-administered questionnaire in the form of sociodemographic profile, non-communicable diseases (NCD) comorbidities (status on hypertension, diabetes and hypercholesterolemia) and NCD risk factors (current smoker and physical activity). Obesity has been defined using the World Health Organization (WHO) Body Mass Index (BMI) guideline, 1998. A complex sampling design analysis was used for the descriptive statistics. The associated risk factors for obesity were identified using Multiple Logistic Regression analysis.ResultsA total of 3794 respondents were included in this study. The prevalence of obesity among Malaysian elderly was 30.2%. The prevalence of obesity among the elderly was significantly higher in females, respondents from urban areas and Indians. Approximately one third of the elderly with non-communicable diseases such as hypertension (33.1%) and diabetes (38.8%), respectively, were obese. Among elderly who were obese, majority of them (89.8%) had at least one NCD. The prevalence of obesity was 16.8% among current smokers (aOR 0.59). Multiple logistic regression analysis revealed that elderly females (aOR [adjusted odds ratio] 1.52), having secondary education (aOR 1.96) with household income of RM 3000 and above (aOR 1.57) as well as being hypertensive (aOR 1.61) and diabetic (aOR 1.50) were more likely to be obese. In contrast, the Chinese elderly respondents (aOR 0.62) and current smokers (aOR 0.59) were less likely to be obese. There were no significant associations of obesity with hypercholesterolemia or with physical activity.ConclusionsA substantial proportion of Malaysian elderly were obese, and factors associated with obesity among them were being female, having secondary education with a household income of RM 3000 and above and being hypertensive or diabetic. Enhanced health promotion and education should be targeted at younger people in order to prevent obesity in the later years.

StratifyR: An R Package for optimal stratification and sample allocation for univariate populations

SummaryThis R package determines optimal stratification of univariate populations under stratified sampling designs using a parametric‐based method. It determines the optimum strata boundaries (OSB), optimum sample sizes (OSS) and multiple other quantities for the study variable, y, using the best‐fit probability density function of a study variable available from survey data. The method requires the parameters and other characteristics of the distribution of the study variable to be known, either from available data or from a hypothetical distribution if the data are not available. In the implementation, the problem of determining the OSB is formulated as a mathematical programming problem and solved by using a dynamic programming technique. If the data of the population (i.e. the study variable) are available to the surveyor, the method estimates its best‐fit distribution and determines the OSB and OSS under Neyman allocation, directly. When the dataset is not available, stratification is made based on the assumption that the values of the study variable, y, are available as hypothetical realisations of proxy values of y from past/recent surveys. Thus, it requires certain distributional assumptions about the study variable. At present, the package handles stratification for the populations where the study variable follows a continuous distribution: namely, Pareto, Triangular, Right‐triangular, Weibull, Gamma, Exponential, Uniform, Normal, Lognormal and Cauchy distributions. In this paper, applications of major functionalities in the package are illustrated with a number of real/simulated as well as some hypothetical populations.

Geographical disparities and determinants of childhood diarrheal illness in Ethiopia: further analysis of 2016 Ethiopian Demographic and Health Survey

BackgroundChildhood diarrheal illness is the second leading cause of child mortality in sub-Saharan Africa, including Ethiopia. Epidemiology of diarrhea has long-term implications with respect to medical, social, and economic consequences. Studies hypothesize that there have been regional differences, and this study aimed to examine the spatial variations and identify the determinants of childhood diarrhea in Ethiopia.MethodsData from the 2016 Demographic and Health Survey of Ethiopia (EDHS), which included 10,337 aged under 5 years were analyzed. The survey was conducted using a two-stage stratified sampling design. The study attempted to detect and test the clustering of diarrhea cases using global Moran’s I and LISA. Descriptive statistics followed by mixed-effect logistic regressions were used to identify factors related to the prevalence of diarrhea.ResultsOverall, 11.87% of the children experienced childhood diarrheal illness. The study showed that the risk was high in the southern and central parts and low in the eastern and western regions of the country. Children aged 6–12 (AOR = 2.66, [95% CI 2.01, 3.52]), 12–23 (AOR = 2.45, [95% CI 1.89, 3.17]), and 24–35 (AOR = 1.53, [95% CI 1.17, 2.01]) months were more likely to suffer from childhood diarrhea than those aged less than 6 months. Children in Tigray (AOR = 1.69 [95% CI 1.01, 2.83]), Amhara (AOR = 1.80, [95% CI 1.06, 3.06]), SNNPR (AOR = 2.04, [95% CI 1.22, 3.42]), and Gambella (AOR = 2.05, [95% CI 1.22, 3.42]) were at higher risk than those in Addis Ababa. The odds of getting diarrhea decreased by 24% among households with ≥ 3 under-five children compared to those with only one under-five child (AOR = 0.76 [95% CI 0.61, 0.94]). The odds of getting diarrheal illness for the children of employed mothers increased by 19% compared to those children of non-employed mothers (AOR = 1.19 [95% CI 1.03, 1.38]).ConclusionsChildhood diarrheal disease is prevalent among under-five children, particularly in the regions of SNNP, Gambella, Oromia, and Benishangul Gumuz, while the regions are generally making progress in reducing childhood illness. Capacity building programs with the best experience sharing and better home environments can be effective in reducing the incidence of childhood diarrhea in Ethiopia.