Hurdle Model Research Articles

FACTORS ASSOCIATED WITH THE USE OF A PERSONALIZED MUSIC INTERVENTION FOR NURSING HOME RESIDENTS WITH DEMENTIA

Abstract Music offers a promising non-pharmacological alternative for managing behavioral dysregulations in people with Alzheimer’s disease and other dementias (ADRD). Using data from an embedded, pragmatic trial (ePCT) of a personalized music intervention for nursing home (NH) residents with ADRD, we examined resident and NH characteristics associated with exposure to the intervention and dose of music received. Participants were enrolled from 54 NHs (27 treatment, 27 control) between June 2019 and February 2020. The intervention was resident-preferred music delivered at early signs of agitation. Intervention dose was calculated by multiplying song duration and number of plays, averaged over days exposed. Facility and resident-level characteristics were identified using the Minimum Data Set and the Certification and Survey Provider Enhanced Reports. A mixed-effects hurdle model was used. 483 residents participated (67.7% female, mean age 79.8±12.2 years). Female residents (p=0.04) taking antipsychotic medications (p=0.06) were more likely to receive the intervention, as were residents from NHs with greater nursing involvement (p=0.02). Residents with greater health instability received a greater dose (p=0.04). In this ePCT of a personalized music intervention, NHs with more nursing engagement had greater use of the intervention and appropriately chose residents with antipsychotic use to participate. After adjusting for initial selection, staff used the intervention more frequently with residents who had a higher likelihood of death in the next six months, potentially indicating the beneficial use for comfort at the end of life. Our findings offer insights into future tailoring of personalized music interventions to increase the likelihood of successful implementation.

How do stand features shape deadwood diversity?

Saproxylic species from different taxonomic groups often occur only on certain types of deadwood with specific qualitative characteristics. The various types of deadwood are very dynamic elements of forest ecosystems, associated with many site and stand features, as well as with the type of forest management. Using a pool of 29,098 sample plots spread across Poland, we analyzed 30 different deadwood types defined on the basis of three characteristics: position (standing, lying), degree of decomposition, and size. Statistical hurdle models were used to assess changes in the volume of individual deadwood types based on a broad range of independent variables. Depending on the type of management, terrain, site fertility, stand volume, tree density, and stand age, the models revealed substantial differences in the volume of different deadwood types, ranging from 0 to approx. 4 m3 ha−1. It was found that the volume of most deadwood types (except for a few, mostly with diameters under 15 cm) increases with stand age or stand volume. In managed forests at all stages of stand development there is a deficiency of thick deadwood. Both standing and lying deadwood at different decay stages is available continuously, irrespective of the values of individual independent variables, but considerable differences exist. While most lying deadwood exhibits higher levels of decomposition, in standing deadwood the proportions of different decay stages are strongly associated with tree diameter at breast height. The developed models make it possible to predict the volume of individual deadwood types for a broad range of independent variables. The current work presents several examples, with the results showing extremely complex relationships between deadwood diversity and site and stand features at every stage of forest development, with continuous changes in the volume and proportions of different deadwood types. In general, at the landscape level Polish forests contain both standing and lying deadwood at all decay stages in more or less equal proportions. However, in forest management one should pay special attention to the dimensions of retained deadwood. The absence of thick deadwood is particularly conspicuous in lowland managed forests.

Consumption patterns of organic vegetable consumers in Ghana

The study examined organic vegetable attributes, consumer decisions and consumption patterns of consumers in Ghana. A sample of 399 consumers was selected using a simple random sampling technique and data was collected through structured questionnaires. The study analyzed the important attributes of organic vegetables using Kendall's coefficient of concordance. The factors influencing consumers' decision to consume organic vegetables and the proportion of their total expenditure allocated to organic vegetables was analyzed using Cragg's double hurdle model. Finally, ordered logit regression was employed to analyse the factors influencing the consumption patterns of organic vegetables consumers. The results revealed that consumers prioritize health concerns and sensory attributes when purchasing organic vegetables as these were identified as the most important attributes. Also, socioeconomic factors, viz. age group, educational level and income level, as well as institutional factors, viz. market type, availability of organic vegetables and accreditation, significantly influenced the decision and expenditure on organic vegetables. In addition, consumers exhibited irregular consumption patterns, and a significant proportion of consumers acquired information about organic vegetables through family and friends. Furthermore, the ordered logit regression analysis revealed several factors that significantly influenced the consumption patterns of organic vegetables. These include age category, educational level, household head, household size, income level, type of market, time to market, and accreditation. The study recommends that government and other stakeholders should consider consumers' consumption patterns, attributes of organic vegetables they consider prior to purchasing as well as factors influencing their decision-making when developing marketing strategies and policies for organic vegetable farmers. This approach can help meet consumer demands and help improve the development and promotion of organic vegetables in the market.

The Applications of Generalized Poisson Regression Models to Insurance Claim Data

Predictive modeling has been widely used for insurance rate making. In this paper, we focus on insurance claim count data and address their common issues with more flexible modeling techniques. In particular, we study the zero-inflated and hurdle-generalized Poisson and negative binomial distributions in a functional form for modeling insurance claim count data. It is shown that these models are useful in addressing the problem of excess zeros and over-dispersion of the claim count variable. In addition, we show that including the exposure as a covariate in both the zero and the count part of the model is an effective approach to incorporating exposure information in zero-inflated and hurdle models. We illustrate the effectiveness and versatility of the introduced models using three real datasets. The results suggest their promising applications in insurance risk classification and beyond.

Long-term effects of a community-based oral health intervention for young children in the Netherlands: A 5-year follow-up.

The aim of this study was to assess whether referral of parents of 6 months old children by a well-child care (WCC) clinic medical practitioner for an early first dental visit combined with the Non Operative Caries Treatment and Prevention (NOCTP) approach in dental practices was effective to maintain oral health in children. The study was conducted as a quasi-experimental comparative pre-post trial with a baseline measurement before the intervention. In total 1347 children were allocated at the age of 6 months and 306 children (intervention group: n = 166; care as usual (CAU) group: n = 140) underwent an oral examination at 5 years of age and their parents completed a questionnaire. Nonparametric tests and Hurdle models were used to determine differences in caries experience between the intervention and CAU groups. Children in the intervention group had significantly lower caries experience (d1,2,3mfs) than children in the CAU group (Median = 2 vs. 5, r = .15, p < .01). Children in the intervention group had significantly fewer inactive caries lesions compared with children in the CAU group (Median = 2 vs. 3, r = .18, p < .001). No differences were found for dentin caries experience and also no differences for active caries lesions. Referral of parents of newborns for a preventive first dental visit by a WCC medical practitioner combined with NOCTP in dental practices may offer a new opportunity to reduce enamel caries lesions in young children.

Digitalization and agricultural transformation in developing countries: Empirical evidence from Tanzania agriculture sector

Agribusiness can potentially increase value for agriculture and the entire value chain, but it is hard to achieve these goals without digitalising the sector. The transformation reforms modern technology and digital infrastructure adoption to facilitate growth and inclusivity. These conditions make the agricultural digitization transformation more appealing. Therefore, using a survey of 400 smallholder farmers in four regions of Rukwa, Ruvuma, Morogoro and Tabora, this study examines the interplay between digitalization and agriculture transformation in Tanzania by focusing on the determinants and effects of digitalization on smallholder farmers' welfare. The study used the double hurdle model to estimate the determinants and extent of digitalization adoption; the Two-stage least square (2SLS) and the Control function approach (CFA) to estimate its effects on smallholder farmers' welfare. The findings revealed that access to credit (0.17428, p < 0.01), extension services (0.52884, p < 0.01), education and government support (0.10922, p < 0.05) are key determinants for agricultural digitalization. Moreover, digitalization was found to influence smallholder farmers' welfare significantly. The benefits of digitalization across smallholder farmers in all regions were observed in enhancing extension services (76.50 %), pest management (71.25 %), and accessibility of the market information (72.25 %), enhance an access to financial services (74.75 %). In sum, to promote digital technology adoption among smallholder farmers, policymakers in Tanzania and developing nations should prioritize financial inclusion through tailored microfinance programs, educational initiatives must integrate digital literacy, enhance extension services, subsidized technology access, and encouraging public-private partnerships to create incentives for sustainable agricultural development.

Determinants of the Efficiency of Electricity Generation in Latin America and Caribbean Countries Using a Cragg’s Regression Model

Measuring and understanding the evolution of the electricity generation efficiency sector is a relevant task for policymakers. This study focuses on assessing the determinants of electricity generation efficiency across 24 countries in Latin America and the Caribbean between 2000 and 2020. A hurdle model was employed to account for the censored nature of the dependent variable. The findings show a positive impact of opening up the electricity sector in fully efficient countries. Market liberalization and the involvement of privately owned power plants contribute to efficiency gains in inefficient countries. Additionally, the tariff protectionism level exhibits positive effects for completely efficient and inefficient countries. These results provide valuable insights, as less-efficient countries can glean strategies from their more efficient counterparts to enhance their electricity generation efficiency.

Determinants of Private Tutoring Demand in Rural India

: Private tutoring participation is increasing in several developing countries, and this expansion has attracted the interest of scholars spanning disciplines of economics, sociology and history. This paper presents a theoretical model of private tutoring demand. The model incorporates the household and school characteristics in a developing country context and demonstrates the source of gender gaps in access to private tutoring. Using a recent database from India and employing a hurdle model approach, the paper also provides estimates of the drivers of private tutoring participation and spending for pre-secondary students. Our results indicate evidence of gender gaps in private tutoring access, and that the socio-economic profile of a student is positively correlated with tutoring demand. Further, school quality indicators are negatively correlated with tutoring participation, suggesting that students at ‘better’ schools rely less on tutoring. Overall, the findings suggest that tutoring demand is influenced by a mix of demand-side (household, community drivers) and supply-side (school quality and learning environment) factors. The results bring into focus the equity implications of tutoring growth and the need to improve school quality in order to reduce the dependence on private tutoring.

Empirical Modelling of Stem Cambium Heating Caused by Prescribed Burning in Mediterranean Pine Forest

Little is known about the interactions between the variables involved in the post-fire response of Mediterranean pine species to prescribed burning (PB). Thus, it is essential to develop an empirical model in order to assess the influence of tree and stand attributes, burn season, and fire severity on the probability of stem cambium damage occurring. Prescribed burnings were conducted in different seasons and areas covering a wide climatic and ecological range. Potential explanatory variables were measured. A random effects hurdle model framework was used to evaluate the temperature duration above 60 °C as a proxy for stem cambium damage at tree scale. The results showed significant differences in cambium damage between the PB seasons. Pinus nigra was more resistant than other pine species. Bark thickness was critical for protecting cambium. Volume of crown scorch, percentage of stem scorch, and maximum outer bark temperature were directly related to temperature duration above 60 °C in the cambium. Prescribed burning conducted under tree canopy in Mediterranean pine species generally results in a low level of cambium damage. Empirical models could help managers to predict the effects of PB and thus select the most suitable prescriptions.

Associations Between Age-Related Hearing Loss, Cognitive Impairment, and Multiple Chronic Conditions in a Group Care Setting.

The purpose of this study was to explore the relationships between hearing loss, cognitive status, and a range of health outcomes over a period of 2 years in a sample of older adults who are enrolled in Program of All-Inclusive Care for the Elderly, which is a Medicare/Medicaid beneficiary program for individuals who are nursing home eligible but living in the community at time of enrollment. The sample (N = 144) includes a diverse (47% White/non-Hispanic, 35% Black/African American, and 16% Latin/Hispanic) group of adults ranging from 55 to 93 years old. We used medical chart data to measure respondents' cognitive and health status, including chronic conditions and hospital use. Hearing status was measured once at the beginning of the 2-year review period. We used logistic regression and negative binomial hurdle models for analyses. We used latent class analysis (LCA) to explore the extent to which respondents cluster into a set of "health profiles" characterized by their hearing, cognitive status, and health conditions. We found that hearing loss is weakly associated with heart disease and diabetes and associated with cerebrovascular disease and falls; cognitive impairment is also associated with cerebrovascular disease and the number of falls. LCA indicates that respondents cluster into a variety of health profiles with a consistent pairing of hearing loss and depression. The results are largely consistent with associations reported in epidemiological studies that include age-related hearing loss. Of particular interest in this study is the LCA that suggested that all of the profiles associated with a high likelihood of hearing loss included a high risk of depression. The co-occurrence of these two factors highlights the need to identify and treat hearing loss in older adults, especially as part of the treatment plan for individuals with depressive symptoms.

Prenatal counseling and maternal health behavior: The case of Ramadan fasting during pregnancy

Abstract Background Ramadan during pregnancy has been found to be associated with various adverse health effects in the offspring, which are largely attributed to maternal intermittent fasting. At the same time, many pregnant Muslims decide to fast during Ramadan. With a growing Muslim population in Europe, Ramadan fasting during pregnancy may become an even more prominent issue in the future. Since pregnant women regularly exchange with healthcare professionals, it is pivotal to evaluate the role of prenatal consultation on Ramadan for the maternal fasting decision. Methods This study uses survey data on pregnant Muslims from Mainz, Germany (N = 326). Data on fasting during pregnancy, consultation with healthcare professionals on fasting during pregnancy, as well as a rich set of socio-economic background characteristics were collected. We estimate the effect of prenatal consultation on the number of days fasted using a log-normal hurdle model. To test whether our controlled estimates might be biased by unobservable confounders, we use the Oster (2019) method. Results The share of women who fasted at least one day was 36.5% (mean: 17 fasted days). Among these women, receiving prenatal consultation on fasting during pregnancy reduced the number of fasted days by 10.8 days (95% CI: -19.03, -2.56). Results from the Oster method show that this result is not biased by unobservable confounders. Conclusions This study shows that prenatal consultation on Ramadan fasting reduces the number of fasted days among pregnant Muslims who intend to fast during pregnancy. These findings imply that prenatal caregivers should be encouraged to discuss Ramadan fasting with their Muslim patients. Further research is needed to develop guidelines for prenatal advice on Ramadan during pregnancy in a framework of shared decision-making. Key messages • Controlled effect estimates show that potentially harmful maternal Ramadan fasting behavior during pregnancy can be mitigated by prenatal caregivers. • This study demonstrates a novel way to exploit real-world data in the absence of randomization by quantitatively assessing the impact of unobservable confounders.

High‐resolution mapping of rabbit (Oryctolagus cuniculus) densities for targeted conservation management

Abstract Despite the staggering economic and ecological impacts of invasive animals, maps of their distribution are often only broad generalisations. Detailed knowledge about the spatial distribution of pest animals is crucial to efficiently reduce their numbers in open landscapes where no conservation fencing, or natural boundaries exist. Our case study tests a random but spatially balanced transect design to collect data on the distribution of the European rabbit (Oryctolagus cuniculus), a major destructive pest species in Australian ecosystems, and create distribution maps in relation to abiotic and biotic features. We surveyed an area of 650 km2 in the semi‐arid Flinders Ranges of South Australia using 95 transects (1.4 km length by 50 m width), that were placed with a method originally developed for surveying the ocean‐floor and applied for the first time in terrestrial ecosystems. According to a hurdle model fitted to our data set, the presence of rabbit warrens is influenced by geology, vegetation cover and the topographic wetness index, whereas the number of holes per warren depends on the ruggedness of the terrain, the vegetation cover and whether it has previously been destroyed. The model predicted the numbers of rabbit holes with up to 96.4% accuracy and at a previously unavailable resolution, providing a significant improvement in detail of the distribution of this feral animal. Synthesis and applications: A reliable, high‐resolution map of the distribution of rabbit densities was generated with surveying of less than 1% of the study area, information that can now be used to direct targeted conservation management efforts. This method is highly accurate and can still be improved in future studies.

Pandemic and Older Adults' Social Structure of Shared Time.

Shared time with family and friends is crucial for older adults' health and well-being. This study examines how a public health crisis affects older adults' social connectedness through their shared time with known persons. The study used data from the 2019-2020 American Time Use Survey (N = 9,697) to assess older adults' (aged 50+) social structure of shared time before and during the coronavirus disease 2019 pandemic. Logistic regression and hurdle model with state-fixed effects were used to estimate the relationships between state-level pandemic severity and measures of older adults' shared time while controlling for sociodemographic characteristics. There were small, statistically significant effects of pandemic severity on older adults' shared time. State-level incidence rates and policy stringency indexes were correlated with a lower likelihood of, and a decline in, older adults' shared time in public places and interactions with individuals outside their immediate family. State policy stringency was associated with more shared time in immediate family interactions. Furthermore, pandemic severity was not associated with a decrease in likelihood and older adults' shared time with nonresident immediate family. Policy stringency was more consequential than the incidence rate for older adults' social structure of shared time during the pandemic. Results indicate a place-based and role-based restructuring of older adults' daily shared time during the pandemic. Despite small effect sizes, the substantial old age population implies significant changes in shared time and patterns of daily connection at the population level. Theoretical and policy implications of the findings are discussed.

An implementation of Hurdle models for spatial count data. Study case: civil war as a risk factor for the development of childhood leukemia in Colombia

We propose a novel, efficient, and powerful methodology to deal with overdispersion, excess zeros, heterogeneity, and spatial correlation. It is based on the combination of Hurdle models and Spatial filtering Moran eigenvectors. Hurdle models are the best option to manage the presence of overdispersion and excess of zeros, separating the model into two parts: the first part models the probability of the zero value, and the second part models the probability of the non-zero values. Finally, gathering the spatial information in new covariates through a spatial filtering Moran vector method involves spatial correlation and spatial heterogeneity to improve the model fitting and explain spatial effects of variables that were not possible to measure. Thus, our proposal adapts usual regression models for count data so that it is possible to deal with phenomena where the usual theoretical assumptions, such as constant variance, independence, and unique distribution are not fulfilled. In addition, this research shows how a prolonged armed conflict can impact the health of children. The data includes children exposed to armed conflict in Colombia, a country enduring a non-international armed conflict lasting over 60 years. The findings indicate that children exposed to high levels of violence, as measured by the armed conflict index, demonstrate a significant association with the incidence and mortality rate of LAP in children. This fact is illustrated here using one of the most catastrophic conditions in childhood, as is Pediatric Acute Leukemia (LAP). The association between armed conflict and LAP has its conceptual basis in the epidemiology literature, given that, the incidence and mortality rates of neoplastic diseases increase with exposure to toxic and chronic stress during gestation and childhood. Our methodology provides a valuable framework for complex data analysis and contributes to understanding the health implications in conflict-affected regions.

Factors associated with scientific production citations in dentistry: Zero-inflated negative binomial regression and hurdle modelling.

Background: The global scientific literature in dentistry has shown important advances in the field, with major contributions ranging from the analysis of the basic epidemiological aspects of prevention to specialised results in the field of dental treatments. The present investigation aimed to analyse the current state of the scientific literature on dentistry hosted in the Web of Science database. Methods: The methodology included two phases in the analysis of articles and indexed reviews in all thematic areas. During the first phase, the following variables were analysed: scientific production by the publisher, the evolution of scientific output published by publishers, the factors associated with the impact of scientific production, and the modelling of the impact of scientific production on dentistry. During the second phase, associations, evolutions, and trends in the use of keywords in the scientific literature in dentistry were analysed. Results: The first phase shows that scientific production in dentistry will increase between 2010 and 2021, reaching 12,126 articles in 2021. Publishers such as Wiley and Elsevier stand out, but Quintessence Publishing has the most citations. Factors such as pages, authors, and references influence the number of citations. Phase 2 analyzes trends in the dental literature using the WoS database. Topics such as "dental education", "pediatric dentistry", and "pandemic" stand out. The intersection of technology and dentistry and the importance of evidence-based education are highlighted. Conclusions: In conclusion, the study shows that the most studied topics include the association of dental education and the curriculum, the association of pediatric dentistry with oral health, and dental care. The findings show that more recently emphasised topics also stand out, such as evidence-based dentistry, the COVID-19 pandemic, infection control, and endodontics, as well as the need for future research to expand current knowledge based on emerging topics in the scientific literature on dentistry.

Spatially explicit models of seed availability improve predictions of conifer regeneration following the 2018 Carr Fire in northern California

For many conifer species in dry conifer forests of North America, seeds must be present for postfire regeneration to occur, suggesting that seed dispersal from surviving trees plays a critical role in postfire forest recovery. However, the application of tree fecundity and spatial arrangement to postfire conifer recovery predictions have only recently become more common, and is often included at relatively coarse scales (i.e., 30 meters). In this study, we mapped surviving trees using lidar and created a spatially explicit estimate of seed density (seed shadows) with 10 m, 50 m, and 100 m median dispersal distances. We estimated the number of seeds produced by each tree using allometric relationships between tree size and fecundity. Along with the seed shadows, we used a suite of topographic variables as inputs to negative binomial hurdle models to predict conifer seedling abundance in 131 plots following the 2018 Carr Fire in northern California, USA. We compared models using each of the seed shadows to each other as well as to a model using the distance to the nearest surviving tree, which served as a baseline. All model formulations indicated that estimated seed availability was positively associated with conifer regeneration. Despite the importance of seed availability plays in regeneration and the substantial differences in seed availability represented by the different seed shadows in our analysis, we found surprisingly little difference in model performance regardless of which seed shadow was used. However, the models employing seed shadows outperformed the models with distance to the nearest live tree. Although we have demonstrated a modest improvement in predicting postfire conifer regeneration, the uncertainty in our results highlights the importance of tree detection and classification in future studies of this kind. Future studies may find it useful to consider other factors such as predation, site suitability, and seed mortality as potential drivers of discrepancies between total and realized dispersal kernels.

Comparison of Hospitalization for Nonaffective Psychotic Disorders Among Refugee, Migrant, and Native-Born Adults in Sweden and Denmark

Determining whether migrants with nonaffective psychotic disorders (NAPDs) experience poorer outcomes after illness onset is essential to ensure adequate health care provision to these disadvantaged populations. To compare cumulative hospital days for NAPDs during the first 5 years of illness among refugee, nonrefugee, and second-generation migrants and their Swedish and Danish peers. This was a prospective cohort study of individuals treated for incident NAPDs in inpatient or outpatient settings between January 1, 2006, and December 31, 2013, and followed up for 5 years. This population-based study used Swedish and Danish national registries. Included participants were individuals in Sweden and Denmark, aged 18 to 35 years, treated for incident NAPDs. Data analyses were conducted from November 2022 to August 2023. Population group (determined according to residency in either country, not both countries), categorized as refugee (migrants whose residence in Sweden or Denmark was registered as refugee status or family reunification with a refugee), nonrefugee (all other individuals born outside Sweden and Denmark), second generation (individuals born in Sweden or Denmark with at least 1 parent born abroad), or native born (individuals born in Sweden or Denmark with both parents born in these countries). Total hospital days for NAPDs during the first 5 years of illness, analyzed using a hurdle model. Among those ever admitted, total number of admissions and mean admission length were examined. In total, 7733 individuals in Sweden (mean [SD] age, 26.0 [5.1] years; 4919 male [63.6%]) and 8747 in Denmark (mean [SD] age 24.8 [5.0] years; 5324 male [60.9%]) were followed up for 5 years or until death or emigration. After adjusting for a range of sociodemographic and clinical factors, the odds of experiencing any hospital days for NAPD were significantly higher among migrant groups compared with their native-born peers (Sweden: second generation, odds ratio [OR], 1.17; 95% CI, 1.03-1.33; P = .01; nonrefugee migrant, OR, 1.45; 95% CI, 1.21-1.73; P < .001; refugee, OR, 1.25; 95% CI, 1.06-1.47; P = .009; Denmark: second generation, OR, 1.21; 95% CI, 1.05-1.40; P = .01; nonrefugee migrant, OR, 1.33; 95% CI, 1.14-1.55; P < .001). These odds were highest among nonrefugee (Sweden: OR, 2.53; 95% CI, 1.59-4.03; P < .001; Denmark: OR, 2.61; 95% CI, 1.70-4.01; P < .001) and refugee (Sweden: OR, 1.96; 95% CI, 1.43-2.69; P < .001; Denmark: OR, 2.14; 95% CI, 1.42-3.21; P < .001) migrants from Africa and those who had arrived within 3 to 5 years (Sweden: nonrefugee migrants, OR, 1.93; 95% CI, 1.26-2.95; P = .002; refugees, OR, 2.38; 95% CI, 1.46-3.88; P < .001; Denmark: nonrefugee migrants, OR, 1.66; 95% CI, 0.96-2.85; P = .07; refugees, OR, 3.40; 95% CI, 1.13-10.17; P = .03). Among those ever hospitalized, refugees in both countries (Sweden, incidence rate ratio [IRR], 1.30; 95% CI, 1.12-1.51; P < .001; Denmark, IRR, 1.47; 95% CI, 1.24-1.75; P < .001) and second-generation migrants in Denmark (IRR, 1.22; 95% CI, 1.07-1.39; P = .003) experienced more days hospitalized for NAPDs than native-born individuals. In this prospective cohort study of individuals with NAPDs, results suggest that refugee, nonrefugee, and second-generation migrants experience more days hospitalized for these disorders than their native-born peers. Patterns were consistent across 2 countries with different models of psychosis care and immigration and integration policies.

Weekly Forecasting of Yellow Fever Occurrence and Incidence via Eco-Meteorological Dynamics.

Yellow Fever (YF), a mosquito-borne disease, requires ongoing surveillance and prevention due to its persistence and ability to cause major epidemics, including one that began in Brazil in 2016. Forecasting based on factors influencing YF risk can improve efficiency in prevention. This study aimed to produce weekly forecasts of YF occurrence and incidence in Brazil using weekly meteorological and ecohydrological conditions. Occurrence was forecast as the probability of observing any cases, and incidence was forecast to represent morbidity if YF occurs. We fit gamma hurdle models, selecting predictors from several meteorological and ecohydrological factors, based on forecast accuracy defined by receiver operator characteristic curves and mean absolute error. We fit separate models for data before and after the start of the 2016 outbreak, forecasting occurrence and incidence for all municipalities of Brazil weekly. Different predictor sets were found to produce most accurate forecasts in each time period, and forecast accuracy was high for both time periods. Temperature, precipitation, and previous YF burden were most influential predictors among models. Minimum, maximum, mean, and range of weekly temperature, precipitation, and humidity contributed to forecasts, with optimal lag times of 2, 6, and 7weeks depending on time period. Results from this study show the use of environmental predictors in providing regular forecasts of YF burden and producing nationwide forecasts. Weekly forecasts, which can be produced using the forecast model developed in this study, are beneficial for informing immediate preparedness measures.

More Interventions, Low Adoption: To What Extent Are the Existing Seed Sources to Blame? The Case of Orange Fleshed Sweet Potato in Central and Northern Malawi

Vitamin A dense Orange fleshed sweet potato (OFSP) has the potential to build resilient livelihoods against Vitamin A Deficiency (VAD), food insecurity, and climate change. However, the adoption of OFSP among smallholder farmers in Malawi remains low. Although many scholars across the globe have reviewed the seed systems of OFSP, no empirical study, in Malawi or elsewhere, has modelled how the use of the various sources of vines affect farmers’ seed security and eventual decisions to adopt biofortified OFSP varieties. The study employed a mixed methods approach and used a Triple Hurdle model to analyze the effect of the existing sources of vines on the adoption of OFSP among 721 randomly sampled households in central and northern Malawi. The study also developed a seed security experience score (SSES) in order to assess the capacity of the existing sources of vines to ensure farmers’ seed security. By defining adoption as a three-stage process, and by shifting the seed systems focus to capacity of the existing sources of vines, the study departs from the conventional approaches that most scholars have used to model adoption of OFSP. The study found that the existing sources of vines influenced all the three stages of adoption. The SSES results indicated that the capacity of the existing sources subjected the majority of the farmers to a highly seed insecurity status. Interventions therefore must be designed to address the seed security challenges associated with the existing sources in order to enhance the capacity of the sources for widespread and sustained adoption of OFSP.

An examination of willingness to participate and willingness to pay for a universal school food program in the Canadian context.

To examine parents'/caregivers' willingness to participate and willingness to pay (WTP) for a cost-shared school food program (SFP) and its associated factors. A quantitative survey design was used where WTP for a hypothetical SFP was elicited using a double-bounded dichotomous choice elicitation method. We used a double hurdle (logistic and truncated regression) model to examine WTP and positively or negatively associated factors. Saskatoon Public School Division elementary schools situated in high-, mid- or low-median-income neighbourhoods. Parents or caregivers of children attending grades 1 to grade 8 in the Saskatoon Public School Division elementary schools. 94 % respondents were willing to participate in a SFP while less than two-thirds of participants were willing to pay for such a program. Over 90 % respondents from all the socio-economic groups were willing to participate. Multiple household income earners, higher household income, higher number of children, household food security status and higher academic attainment of parents'/caregivers predicted greater willingness to pay. Mean willingness to pay was $4·68 (CAN), and households reporting moderate or severe food insecurity were likely to be willing to pay significantly less for a SFP. A cost-shared program might be financially sustainable in Canada if community characteristics such as household food insecurity status, economic participation of women and average household size are kept in mind while determining the price of the program.