Association of Population Density and Distance to the City with the Risks of COVID-19: A Bayesian Spatial Analysis

The outbreak of Coronavirus disease-2019 (Covid-19) poses a severe threat around the world. Although several studies of modelling Covid-19 cases have been done, there appears to have been limited research into modelling Covid-19 using Bayesian hierarchical spatial models. This study aims to examine the most suitable Bayesian spatial CAR Leroux models in modelling the number of confirmed Covid-19 cases without and with covariates namely distance to the capital city and population density. Data on the number of confirmed positive cases of Covid-19 (March 20, 2020 - August 30, 2021) in 15 sub-districts in Makassar City, the number of populations, population density, and distance to the city are used. The best model selection is based on several criteria, namely Deviance Information Criteria (DIC), Watanabe Akaike Information Criteria (WAIC), residuals from Moran’s I Modification (MMI), and the 95% credible interval does not contain zero. The results showed that the best model in modelling Covid-19 is spatial CAR Leroux with hyperprior Inverse-Gamma (0.5, 0.05) model with the incorporation of distance to the capital city. It is found that there was a negative correlation between the distance to the capital city and Covid-19 risk, but the association between population density and the relative risk of Covid-19 was not statistically significant. Ujung Pandang district and Sangkarrang Island have the highest and the lowest relative risk respectively.

Predicting species distribution from fishers’ local ecological knowledge: a new alternative for data-poor management

Many developing countries lack information to manage their endangered species, urging the need for affordable and reliable information. We used Bayesian hierarchical spatial models, with oceanographic variables, to predict the distribution range of Epinephelus marginatus, the dusky grouper, for the entire Southwest Atlantic. We ran a model using scientific information gathered from the literature and another using information gathered from fishers on species presence or absence. In both models, temperature was an important determinant of species occurrence. The predicted occurrence of the dusky grouper overlapped widely (Schoener’s D = 0.71; Warren’s I = 0.91) between the models, despite small differences on the southern and northern extremes of the distribution. These results suggest that basic information provided by fishers on species occurrence in their area can be reliable enough to predict species occurrence over large scales and can be potentially useful for marine spatial planning. Fishers’ knowledge may be an even more viable alternative to data collection than what was previously thought, for countries that both struggle with financial limitations and have urgent conservation needs.

Spatial analysis of incidence of cutaneous melanoma in the Friuli Venezia Giulia region in the period 1995-2005

Incidence distribution of cutaneous melanoma depends on phenotypic characteristics of population and geographic location. In Italy, in the period 1999-2003 Friuli Venezia Giulia (FVG) region had the second highest incidence rates for males and the third for females. We analysed melanoma and lip cancer incidence data of the FVG cancer registry for the period 1995-2005. We used Bayesian hierarchical spatial models to describe the spatial pattern by gender. We decomposed the geographical distribution of the risk in two parts: a component linked to chronic exposure and a component related to intermittent exposure. In order to model the chronic component we considered the geographical distribution of incidence cases of lip cancer, for which chronic occupational solar radiation exposure is a documented risk factor. We also analysed the distribution by site and we calculated standardised rates for body surface area. This study documents a significant gradient in the incidence of cutaneous melanoma in FVG. Highstandardisedincidence rates are present in the area of Trieste and in the coastal area. The descriptive analysis by age group and by site, showed risks associated with intermittent exposures in both genders. For the coastal area the risk is especially high for sites traditionally linked to high cumulative exposures (face and neck), especially among men. The results suggest diagnostic preventive interventions in the populations living in the area of Trieste, given the high rates observed in the young age groups.