Computational and statistical approaches for quantifying the role of multi-scale heterogeneity in Leishmania transmission dynamics

Leishmaniasis, a neglected tropical disease caused by infection with Leishmania parasites, affects millions of people annually across the globe. Leishmania transmission is facilitated by the sand fly vector, thus occurring across a range of climates with notable hotspots in Brazil and India. Its persistence despite ongoing eradication efforts underscores the importance of a complete understanding of the transmission dynamics in a range of environments. Developing this understanding requires tailored tools as the transmission dynamics are affected by heterogeneity at multiple scales, giving rise to a complex web of interactions. At the micro-scale, transmission is influenced by the heterogeneous parasite distributions of the host’s skin as well as the complex parasite life cycle in the sand fly and its link to sand fly biting behaviour. We derive and parameterise a simple model incorporating these factors, finding that their interactions give rise to unexpected transmission opportunities. The communities in which leishmaniasis typically propagates are highly heterogeneous but also ideal candidates for deploying network models. We test analytic estimates for two epidemiologically relevant quantities, the R0 (the average number of secondary infections caused by a single infected individual over their entire duration of infection) and the endemic equilibrium, in the context of heterogeneous networks. Although both prove to be unreliable for these structured communities, they have the potential to improve our understanding of when and where epidemics are likely to occur and be more severe. We also demonstrate the potential of using survival analysis to investigate medium and large-scale dynamics, first by confirming the role of distance in leishmaniasis transmissibility at the community level, and then by highlighting the role of social vulnerability in creating endemic hotspots. We then offer guidance for optimal application of survival analysis to future leishmaniasis research. Finally, these findings are synthesised with the wider literature to identify potential methodological improvements and further avenues of inquiry to further develop our knowledge of leishmaniasis transmission

Emergency Department Repair of Blunt Right Atrial Rupture Utilizing Cardiopulmonary Bypass

Blunt cardiac injury (BCI) with free wall rupture carries a high risk of pre-hospital death. Cardiopulmonary bypass (CPB) has been utilized as a bridge to repair of cardiac lesions in select patients. We present an interesting case of emergency department repair of right atrial rupture with cardiopulmonary bypass

Floating oil-covered debris from Deepwater Horizon : identification and application

Author Posting. © IOP Publishing, 2012. This article is posted here by permission of IOP Publishing. Re-use is limited to non-commercial purposes. The definitive version was published in Environmental Research Letters 7 (2012): 015301, doi:10.1088/1748-9326/7/1/015301.The discovery of oiled and non-oiled honeycomb material in the Gulf of Mexico surface waters and along coastal beaches shortly after the explosion of Deepwater Horizon sparked debate about its origin and the oil covering it. We show that the unknown pieces of oiled and non-oiled honeycomb material collected in the Gulf of Mexico were pieces of the riser pipe buoyancy module of Deepwater Horizon. Biomarker ratios confirmed that the oil had originated from the Macondo oil well and had undergone significant weathering. Using the National Oceanic and Atmospheric Administration's records of the oil spill trajectory at the sea surface, we show that the honeycomb material preceded the front edge of the uncertainty of the oil slick trajectory by several kilometers. We conclude that the observation of debris fields deriving from damaged marine materials may be incorporated into emergency response efforts and forecasting of coastal impacts during future offshore oil spills, and ground truthing predicative models.This research was supported by NSF grant OCE-1043976 to CR

Consideration of urban green space in impact assessments for health

This paper explores how health aspects connected with the planning of urban green space are currently supported through two types of impact assessments: health impact assessment (HIA) and environmental assessment, including strategic environmental assessment (SEA) of policies, plans and programmes and environmental impact assessment (EIA) of projects. Seven HIAs and five EIAs/SEAs from the UK, the US, the Netherlands, Austria and Germany are reviewed, using an analytical framework designed on the basis of a literature review. An important finding is that whilst all HIAs follow a problem-/objectives-driven approach, designing guidelines for potential future projects, all EIAs/SEAs use an impact-driven approach, focusing on the impacts of planned and concrete action. HIAs therefore approach policy, plan, programme and project-making exercises from the outside, making suggestions to those working on them to consider certain aspects in the future, rather than working with them on improving things within a decision making process, as is usually is usually the case with EIAs/SEAs

Understanding the acceleration in the ring-opening of lactones delivered by microwave heating

AbstractThis paper reports the first detailed study focussed upon identifying the influence that microwave heating (MWH) has upon the mechanic steps involved in the tin catalysed ring-opening of lactones such as ɛ-caprolactone (CL). Direct comparison of conventional (CH) and microwave (MWH) heated kinetic studies showed that a key factor in the reduction of the polymerisation cycle time with MWH was the elimination of the induction period associated with in situ catalyst manufacture and initiation. NMR studies demonstrated that the most significant mechanistic change contributing to the observed induction time reduction/elimination was faster initiation (i.e., reaction of the initiatior/catalyst complex with the first monomer unit). Consequently, analysis of the dielectric properties of the reaction components predicted that this MWH induced change was related to the selective volumetric heating of both the catalyst and the monomer. Furthermore, this indication of the greater significance of the initiation step in defining the length of the induction period suggests that this is the rate determining step of the process, whether conducted by CH or MWH. Increasing the catalyst concentration was demonstrated to produce significant reductions in reaction heat-up time and to induce a significant (up to 30 °C) overshoot in reaction mixture bulk temperature in with MWH only. Thus supporting the conclusion that selective heating of the organometallic species in the system contributes directly to differences in the reaction conditions and which need to be taken into account when drawing comparisons with CH systems. Consequently, both effects were concluded to be thermally generated from selective volumetric heating

On the differences in the vertical distribution of modeled aerosol optical depth over the southeastern Atlantic

The southeastern Atlantic is home to an expansive smoke aerosol plume overlying a large cloud deck for approximately a third of the year. The aerosol plume is mainly attributed to the extensive biomass burning activities that occur in southern Africa. Current Earth system models (ESMs) reveal significant differences in their estimates of regional aerosol radiative effects over this region. Such large differences partially stem from uncertainties in the vertical distribution of aerosols in the troposphere. These uncertainties translate into different aerosol optical depths (AODs) in the planetary boundary layer (PBL) and the free troposphere (FT). This study examines differences of AOD fraction in the FT and AOD differences among ESMs (WRF-CAM5, WRF-FINN, GEOS-Chem, EAM-E3SM, ALADIN, GEOS-FP, and MERRA-2) and aircraft-based measurements from the NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign. Models frequently define the PBL as the well-mixed surface-based layer, but this definition misses the upper parts of decoupled PBLs, in which most low-level clouds occur. To account for the presence of decoupled boundary layers in the models, the height of maximum vertical gradient of specific humidity profiles from each model is used to define PBL heights. Results indicate that the monthly mean contribution of AOD in the FT to the total-column AOD ranges from 44 % to 74 % in September 2016 and from 54 % to 71 % in August 2017 within the region bounded by 25∘ S–0∘ N–S and 15∘ W–15∘ E (excluding land) among the ESMs. ALADIN and GEOS-Chem show similar aerosol plume patterns to a derived above-cloud aerosol product from the Moderate Resolution Imaging Spectroradiometer (MODIS) during September 2016, but none of the models show a similar above-cloud plume pattern to MODIS in August 2017. Using the second-generation High Spectral Resolution Lidar (HSRL-2) to derive an aircraft-based constraint on the AOD and the fractional AOD, we found that WRF-CAM5 produces 40 % less AOD than those from the HSRL-2 measurements, but it performs well at separating AOD fraction between the FT and the PBL. AOD fractions in the FT for GEOS-Chem and EAM-E3SM are, respectively, 10 % and 15 % lower than the AOD fractions from the HSRL-2. Their similar mean AODs reflect a cancellation of high and low AOD biases. Compared with aircraft-based observations, GEOS-FP, MERRA-2, and ALADIN produce 24 %–36 % less AOD and tend to misplace more aerosols in the PBL. The models generally underestimate AODs for measured AODs that are above 0.8, indicating their limitations at reproducing high AODs. The differences in the absolute AOD, FT AOD, and the vertical apportioning of AOD in different models highlight the need to continue improving the accuracy of modeled AOD distributions. These differences affect the sign and magnitude of the net aerosol radiative forcing, especially when aerosols are in contact with clouds.</p

Inequalities in public water supply fluoridation in Brazil: An ecological study

Background. The literature is scarce on the social and geographic inequalities in the access to and implementation of the fluoridation of public water supplies. This study adds knowledge to the Brazilian experience of the chronic privation of water and wastewater policies, access to potable water and fluoridation in the country. Thus, the aim of this study was to verify possible inequalities in the population's access to fluoridated drinking water in 246 Brazilian municipalities. Methods. The information on the process of water fluoridation in the municipalities and in the macro region in which each municipality is located was obtained from the national epidemiological survey which was concluded in 2003. The data relating to the human development index at municipal level (HDI-M) and access to mains water came from the Brazilian Human Development Atlas, whilst the size of the population was obtained from a governmental source. The Fisher exact test (P < 0.05) was employed to identify significant associations between the explanatory variables and their ability to predict the principal outcomes of interest to this study, namely the presence or absence of the water fluoridation process in the municipalities as well as the length of time during which this measure has been implemented. Linear regression was used to observe the associations between the relevant variables in a multivariate environment. Results. The results clearly showed that there is a relationship between municipalities with larger populations, located in more socio-economically advantaged regions and with better HDI-M, and where fluoridation is both present and has been implemented for a longer period of time (started before 1990). Conclusion. 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(2006) Sozial und Präventiv Medizin, 51 (5), pp. 1-9Peres, K.G., Bastos, J.R., Mrdo, L., Relationship between severity of dental caries and social and behavioral factors in children (2000) Rev Saude Publica, 34 (4), pp. 402-8. , 10973161Maltz, M., Barbachan Silva, E.B., Relationship between caries, gingivitis and fluorosis and the socioeconomic status among school children (2001) Rev Saude Publica, 35 (2), pp. 170-6. , 11359204Moysés, S.J., Desigualdades em Sade Bucal e Desenvolvimento Humano: Um ensaio em preto, branco e alguns tons de cinza (2001) Rev Bras Odontol Sade Coletiva, 1 (1), pp. 7-17Patussi, M.P., Marcenes, W., Croucher, R., Sheiham, A., Social deprivation, income inequality, social cohesion and dental caries in Brazilian school children (2001) Soc Sci Med, 53 (7), pp. 915-25. , 10.1016/S0277-9536(00)00391-9 11522137Antunes, J.L.F., Frazão, P., Narvai, P.C., Bispo, C.M., Pegoretti, T., Spatial analysis to identify differentials in dental needs by area-based measures (2002) Community Dent Oral Epidemiol, 30 (2), pp. 133-42. , 10.1034/j.1600-0528.2002.300207.x 12000354Peres, M.A., Peres, K.G., Antunes, J.L.F., Junqueira, S.R., Frazão, P., Narvai, P.C., The association between socioeconomic development at the town level and the distribution of dental caries in Brazilian children (2003) Rev Panam Salud Publica, 14 (3), pp. 149-57. , 10.1590/S1020-49892003000800001 14653902Antunes, J.L.F., Narvai, P.C., Nugent, Z.J., Measuring inequalities in the distribution of dental caries (2004) Community Dent Oral Epidemiol, 32 (1), pp. 41-8. , 10.1111/j.1600-0528.2004.00125.x 14961839Antunes, J.L.F., Peres, M.A., De Campos Mello, T.R., Waldman, E.A., Multilevel assessment of determinants of dental caries experience in Brazil (2006) Community Dent Oral Epidemiol, 34 (2), pp. 146-152. , 10.1111/j.1600-0528.2006.00274.x 16515679Narvai, P.C., Frazão, P., Roncalli, A.G., Antunes, J.L.F., Dental caries in Brazil: Decline, polarization, inequality and social exclusion (2006) Rev Panam Salud Publica, 19 (6), pp. 385-93. , 10.1590/S1020-49892006000600004 16968593Projeto, S.B., Brasil, Condiçes de sade bucal da população brasileira 2002-2003. 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Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant