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Integrated stratigraphy of the latest Barremian-early Albian interval in the western part of the Tethyan margin : new data from the Essaouira-Agadir Basin (Western Morocco)
No full textThe Essaouira-Agadir Basin (EAB, Morocco) presents numerous and well-exposed outcrops of the Lower Cretaceous series. Here we present an integrated stratigraphic framework for the latest Barremian-early Albian, and for the western Tethys based on i) the identification of sedimentary discontinuities, ii) the establishment of a high-resolution ammonite and calcareous nannofossil biozonation, and iii) a carbon isotope record. Various sedimentary discontinuities corresponding to erosive surfaces were recognized within these deposits. Most of these surfaces are correlated within the EAB, and correspond to drops in sea level. The distribution of ammonite assemblages was calibrated with the standard Mediterranean zonation. Several ammonite index-species have been identified, in particular for the early Aptian and earliest late Aptian. This was crucial because the lower series are dominated by condensed sedimentation and temporal hiatuses. Most of the uppermost Barremian to lower Albian ammonite standard zones have been recognized. Four new and reliable calcareous nannofossil bioevents have been identified in the late Aptian allowing to revise the NC7 Zone. The taxonomic criteria used to define species markers of both NC8A and NC8B subzones have been specified, thereby improving the calibration of these subzones with ammonite biozones. The delta C-13(carb) values from whole rock samples decrease from the late Aptian to the early Albian. The new biostratigraphic and chemostratigraphic scheme for the EAB allowed rather good correlations between sections from southern and northern Tethyan margins
High methylmercury uptake by green algae in Lake Titicaca : potential implications for remediation
No full textAnthropogenic pressure in the high altitude lakes such as Titicaca and Uru (Bolivia) may favor the production of methylmercury (MeHg) known to accumulate in trophic chains. Periphyton associated with emerged aquatic plants (totoras) from the lake shores accumulates and demethylates MeHg providing a potential cost-effective water treatment technique. In this laboratory study, we measured the MeHg uptake kinetics of a consortium of green algae isolated from Lake Titicaca totora's periphyton. The most abundant algal consortium, composed of Oedogonium spp., Chlorella spp., Scenedesmus spp., was exposed to rising MeHg concentrations (from 5 to 200 ng.L-1) to assess their maximum potential capacity for MeHg accumulation. Various algal biomass concentra-tions were tested to choose the optimal one. Results provided a net MeHg uptake rate by this algal consortium of 2.38 amol ng(-1).h(-1).nM(-1) (the total uptake was 2863 ng MeHg.g(-1)) for an initial concentration of 200 ng MeHg.L-1 with an algal biomass concentration of 0.02 g.L-1. This initial MeHg concentration is 1000 times higher than the one measured in the eutrophic Cohana Bay of Lake Titicaca, which shows the high accumulation potential of these green algae. Our data suggest that periphyton has a high potential for the treatment of Hg contaminated waters in constructing wetlands in the Andean Altiplano
Compound-specific delta H-2 and delta C-13 values of n-alkanes as a tool to unravel complex petroleum mixtures in the South Viking Graben, Norway
No full textIn order to resolve oil mixtures and for oil-source correlation purposes, both hydrogen (82H) and carbon isotope compositions (delta C-13) of n-alkanes and acyclic isoprenoid alkanes have been determined in petroleum mixtures and extracts from Jurassic source rocks of distinct organic matter type, depositional setting and lithology in the South Viking Graben, Norway. delta H-2 values vary from-80 to-140 parts per thousand for n-alkanes and from-130 to-165 parts per thousand for pristane (Pr) and phytane (Ph) in oil and condensate samples. At the same maturity level, in the main oil generative window, individual n-alkanes from most oils and condensates show a H-2-enrichment with n-alkane chain length by 15 to 50 parts per thousand. With the increase in the estimated input of hydrocarbons from terrigenous source material to petroleum mixtures, the n-alkanes (>C-20) exhibit a higher 2H-enrichment while n-alkanes (C-10-C-14) show a higher C-13-enrichment. delta H-2 values of n-alkanes (>C-20) are useful to discriminate mixed oils that were not well differentiated by delta C-13 data. delta H-2 values of individual n-alkanes from oils suggest a possible exchange of C-bound H with other hydrogen during their generation from precursor molecules. We find that delta H-2 values of n-alkanes from Jurassic source rock extracts, at the onset of oil generation, were mainly controlled by the isotopic composition of biosynthetic precursors and varied from-100 to-150 parts per thousand. Combination of carbon and hydrogen isotope compositions of n-alkanes proved to be a useful tool to discriminate Jurassic petroleum mixtures from distinct sources in the Norwegian South Viking Graben
The vulnerability of shellfish farmers to HAB events : an optimal matching analysis of closure decrees
No full textHarmful Algal Blooms (HAB) events may have serious economic consequences for shellfish farmers. When toxic algae blooms threaten human health, public authorities may decide to shut down the farming business for a while, i.e. ranging from a few days to several weeks or months, according to the severity of risks. The impact of closures being temporally and spatially distributed, shellfish farmers can avoid the risky zones or develop adaptive strategies to mitigate the economic consequences and therefore reduce significantly their business sensitivity to HABs. A sequential approach by optimal matching analysis is applied to an original data set of shellfish area closure decrees between April 2004 and December 2018 in Southern Brittany and Pays de la Loire (France) to build a typology of 79 aquaculture zones affected by various HAB and microbiological hazards (ASP, DSP, Norovirus, E. Coli, oil spills). The hypothesis is that the degree of exposure to the HAB hazard assessed by zonal closures may not be correlated to the level of sensitivity revealed by the economic results of the shellfish farming industry which can develop avoidance strategies
Estimating the local spatio-temporal distribution of malaria from routine health information systems in areas of low health care access and reporting
No full textBackground Reliable surveillance systems are essential for identifying disease outbreaks and allocating resources to ensure universal access to diagnostics and treatment for endemic diseases. Yet, most countries with high disease burdens rely entirely on facility-based passive surveillance systems, which miss the vast majority of cases in rural settings with low access to health care. This is especially true for malaria, for which the World Health Organization estimates that routine surveillance detects only 14% of global cases. The goal of this study was to develop a novel method to obtain accurate estimates of disease spatio-temporal incidence at very local scales from routine passive surveillance, less biased by populations' financial and geographic access to care. Methods We use a geographically explicit dataset with residences of the 73,022 malaria cases confirmed at health centers in the Ifanadiana District in Madagascar from 2014 to 2017. Malaria incidence was adjusted to account for underreporting due to stock-outs of rapid diagnostic tests and variable access to healthcare. A benchmark multiplier was combined with a health care utilization index obtained from statistical models of non-malaria patients. Variations to the multiplier and several strategies for pooling neighboring communities together were explored to allow for fine-tuning of the final estimates. Separate analyses were carried out for individuals of all ages and for children under five. Cross-validation criteria were developed based on overall incidence, trends in financial and geographical access to health care, and consistency with geographic distribution in a district-representative cohort. The most plausible sets of estimates were then identified based on these criteria. Results Passive surveillance was estimated to have missed about 4 in every 5 malaria cases among all individuals and 2 out of every 3 cases among children under five. Adjusted malaria estimates were less biased by differences in populations' financial and geographic access to care. Average adjusted monthly malaria incidence was nearly four times higher during the high transmission season than during the low transmission season. By gathering patient-level data and removing systematic biases in the dataset, the spatial resolution of passive malaria surveillance was improved over ten-fold. Geographic distribution in the adjusted dataset revealed high transmission clusters in low elevation areas in the northeast and southeast of the district that were stable across seasons and transmission years. Conclusions Understanding local disease dynamics from routine passive surveillance data can be a key step towards achieving universal access to diagnostics and treatment. Methods presented here could be scaled-up thanks to the increasing availability of e-health disease surveillance platforms for malaria and other diseases across the developing world
Whole-genome assemblies of 16 Burkholderia pseudomallei isolates from rivers in Laos
No full textWe report 16 Burkholderia pseudomallei genomes, including 5 new multi-locus sequence types, isolated from rivers in Laos. The environmental bacterium B. pseudomallei causes melioidosis, a serious infectious disease in tropical and subtropical regions. The isolates are geographically clustered in one Glade from around Vientiane, Laos, and one Glade from further south
Estimating fishing effort in small-scale fisheries using GPS tracking data and random forests
No full textDuring the last decade spatial patterns of industrial fisheries have been increasingly characterized using tracking technologies and machine learning analytical algorithms. In contrast, for small-scale fisheries, fishers' behaviour for estimating and mapping fishing effort has only been anecdotally explored. Following a comparative approach, we conducted a boat tracking survey in a small-scale reef fishery in Madagascar and investigated the performance of a learning random forest algorithm and a speed threshold for estimating and mapping fishing effort. We monitored the movements of a sample of 31 traditional sailing fishing boats at around 45 s time interval using small GPS trackers. A total of 306 daily tracks were recorded among five gear types (beach seine, mosquito trawl net, gillnet, handline, and speargun). To ground-truth GPS location data, fishers' behaviour was simultaneously recorded by a single on-board observer for 49 tracks. Typical, gear-specific track patterns were observed. Overall, the random forest model was found to be the most reliable, generic, and complex method for processing boat GPS tracks and detecting spatially-explicit fishing events regardless gear type. Predictions of mean fishing effort per trip showed that both methods reached from 89.4% to 97.0% accuracy across gear types. Our findings showed that boat tracking combined with on-board observation would improve the reliability of spatial fishing effort indicators in small-scale fisheries and contribute to more efficient management. Selection of the most appropriate GPS data processing method is dependent on local gear use, fishing effort indicators, and available analytical expertise
Description of participants in the "Atout Age Mobility" prevention workshops at the University Hospital Center of La Réunion : a prospective study
No full textIntroduction As the population ages, loss of autonomy is becoming a priority public health issue. "Atout Age Mobility" prevention interventions for seniors aim to limit frailty, which is a predictive and reversible factor in the loss of autonomy and disability. Objectives The objective of this study is to describe the impact of these interventions on the physical performance and quality of life of a pilot sample of participants. Design We conducted a prospective study named 5P PILOT with 3 months of follow up. Settings Subjects were recruited by convenience sampling from participants in the "Atout Age Mobility" workshops at Saint Joseph from 04/09/2017 to 29/01/2019. Participants Retired people over 55 years old with no contraindications to physical activity recruited from participants in the "Atout Age Mobility" workshops in Saint Joseph. Intervention(s) (for clinical trials) or Exposure(s) (for observational studies): All participants completed 12 weeks of physical exercise called the "Atout Age Mobility" workshop, which lasted 60 minutes each week and was supervised by physical activity coaches. Main Outcome(s) and Measure(s) Physical performance was assessed by Short physical performance battery (SPPB), 10-m gait speed and grip strength measurement. Quality of life through the SF-36 test. Results Ninety-six patients were included and 55 (57.3%) completed the study. There was a significant improvement in gait speed (1.35 +/- 0.26m/s vs. 1.27 +/- 0.24m/s; p=0.008). There was no significant change in SF-36, grip strength dominant arm and SPPB at the 0.01 significance level. Conclusion The "Atout Ages Mobility" workshops seem to significantly improve gait speed but not other aspects of physical performance or quality of life
Sustainability determinants of the Burkinabe performance-based financing project
No full textPurpose A performance-based financing (PBF) pilot project was implemented in 2011 in Burkina Faso. After more than five years of implementation (data collection in 2016), the project's sustainability was not guaranteed. This study's objective is to assess this project's sustainability in 2016 by identifying the presence/absence of different determinants of sustainability according to the conceptual framework of Seppey et al. (2017). Design/methodology/approach It uses a case study approach using in-depth interviews with various actors at the local, district/regional and national levels. Participants (n = 37) included health practitioners, management team members, implementers and senior members of health directions. A thematic analysis based on the conceptual framework was conducted, as well as an inductive analysis. Findings Results show the project's sustainability level was weak according to an unequal presence of sustainability's determinants; some activities are being maintained but not fully routinised. Discrepancies between the project and the context's values appeared to be important barriers towards sustainability. Project's ownership by key stakeholders also seemed superficial despite the implementers' leadership towards its success. The project's objective towards greater autonomy for health centres was also directly confronting the Burkinabe's hierarchical health system. Originality/value This study reveals many fits and misfits between a PBF project and its context affecting its ability to sustain activities through time. It also underlines the importance of using a conceptual framework in implementing and evaluating interventions. These results could be interesting for decision-makers and implementers in further assessing PBF projects elsewhere
Social structure, habitat use and injuries of Indo-Pacific bottlenose dolphins (Tursiops aduncus) reveal isolated, coastal, and threatened communities in the South Pacific
No full textUnderstanding population structure and habitat use of poorly known cetacean species is a first step toward scientifically informed management decisions. In the southern range of New Caledonia (South Pacific), a long-term dataset of Indo-Pacific bottlenose dolphins (Tursiops aduncus) encounters primarily during winter seasons 1997 to 2019 (473 group observations) was used to assess social structure, habitat use and potential threats. A total of 338 individuals were photographically identified, forming three distinct communities in the south-west lagoon, the south lagoon and the Isle of Pines. Mark-recapture histories revealed that the three communities were weakly connected and might be considered as independent management units. Suitable habitats were estimated with presence-only distribution models relative to topographic and seabed substrate predictors. Habitat suitability increased with proximity to coasts or reefs, at shallow depth, and over muddy bottom. These habitats had various levels of protection and were used by humans, mostly in the south-west lagoon. External injuries were interpreted to determine natural interactions and potential anthropogenic threats. The prevalence in injuries did not vary among the three areas. A substantial proportion of injuries related to propeller hits was reported, representing a total of 16.7% (34 of 204) of all injuries observed on dolphins. The three communities of Indo-Pacific bottlenose dolphins revealed in the southern part of New Caledonia are particularly vulnerable due to their insularity, their coastal habitat use and the low levels of connectivity found among them. In a context of increasing maritime traffic, fishing and recreational activities, this study provides a useful baseline to the urgent assessment of the conservation status of dolphins in New Caledonia