93484 research outputs found
Sort by
Acceptabilité des outils d'évaluation de la fragilité des seniors : de la théorie à la pratique
No full textThe impact of the obstetrical risk insurance scheme in Mauritania on maternal healthcare utilization : a propensity score matching analysis
No full textIn Mauritania, obstetrical risk insurance (ORI) has been progressively implemented at the health
district level since 2002 and was available in 25% of public healthcare facilities in 2015. The ORI
scheme is based on pre-payment scheme principles and focuses on increasing the quality of and
access to both maternal and perinatal healthcare. Compared with many community-based health
insurance schemes, the ORI scheme is original because it is not based on risk pooling. For a
pre-payment of 16-18 USD, women are covered during their pregnancy for antenatal care, skilled
delivery, emergency obstetrical care [including caesarean section (C-section) and transfer] and a
postnatal visit. The objective of this study is to evaluate the impact of ORI enrolment on maternal
and child health services using data from the Multiple Indicator Cluster Survey (MICS) conducted
in 2015. A total of 4172 women who delivered within the last 2 years before the interview were
analysed. The effect of ORI enrolment on the outcomes was estimated using a propensity score
matching estimation method. Fifty-eight per cent of the studied women were aware of ORI, and
among these women, more than two-thirds were enrolled. ORI had a beneficial effect among the
enrolled women by increasing the probability of having at least one prenatal visit by 13%, the
probability of having four or more visits by 11% and the probability of giving birth at a healthcare
facility by 15%. However, we found no effect on postnatal care (PNC), C-section rates or neonatal
mortality. This study provides evidence that a voluntary pre-payment scheme focusing on pregnant
women improves healthcare services utilization during pregnancy and delivery. However,
no effect was found on PNC or neonatal mortality. Some efforts should be exerted to improve
communication and accessibility to OR
At-sea movements of wedge-tailed shearwaters during and outside the breeding season from four colonies in New Caledonia
No full textThe wedge-tailed shearwater (WTS) population of New Caledonia is one of thelargest in the world, yet its biology and foraging ecology are poorly known. We studied WTS from 4colonies in New Caledonia. We examined foraging behaviour and habitats using GPS receivers andlight sensors during and outside the breeding season, respectively, and compared our findings withthose from other WTS populations worldwide. During breeding, New Caledonian WTS alternatedshort foraging trips close to the colony over the lagoon, or off the reef edge, with longer trips overdistant, deep waters. Whereas neighboring colonies overlapped at sea, especially during short trips,there was a clear separation of foraging zones between the pairs of colonies located in the southernversus northwestern parts of New Caledonia. Although WTS actively foraged and commuted to for-aging zones during the day, they mainly returned to the colony or rested at night, indicating thatthey feed mainly during the day. Active foraging did not take place in more productive areas, sug-gesting that it may instead be related to the presence of sub-surface predators. Outside the breed-ing season, birds from 3 colonies had similar trans-equatorial migratory behaviour. All left NewCaledonia at the same time of the year with a fast, northeasterly movement and wintered over deepwaters in the same sector of the northwestern tropical Pacific Ocean. At overwintering sites, theyspent most of their non-foraging time presumably sitting on the water, especially at night, makinga slow westward movement before returning to New Caledonia. WTS from New Caledonia forageover warm, oligotrophic deep waters throughout their life cycle, and the species appears to have aflexible foraging strategy adapted to the various environmental conditions encountered across its wide tropical range
Linking hunting weaponry to attack strategies in sailfish and striped marlin
No full textLinking morphological differences in foraging adaptations to prey choice and feeding strategies has provided major evolutionary insights across taxa. Here, we combine behavioural and morphological approaches to explore and compare the role of the rostrum (bill) and micro-teeth in the feeding behaviour of sailfish (Istiophorus platypterus) and striped marlin (Kajikia audax) when attacking schooling sardine prey. Behavioural results from high-speed videos showed that sailfish and striped marlin both regularly made rostrum contact with prey but displayed distinct strategies. Marlin used high-speed dashes, breaking schools apart, often contacting prey incidentally or tapping at isolated prey with their rostra; while sailfish used their rostra more frequently and tended to use a slower, less disruptive approach with more horizontal rostral slashes on cohesive prey schools. Capture success per attack was similar between species, but striped marlin had higher capture rates per minute. The rostra of both species are covered with micro-teeth, and micro-CT imaging showed that species did not differ in average micro-tooth length, but sailfish had a higher density of micro-teeth on the dorsal and ventral sides of their rostra and a higher amount of micro-teeth regrowth, suggesting a greater amount of rostrum use is associated with more investment in micro-teeth. Our analysis shows that the rostra of billfish are used in distinct ways and we discuss our results in the broader context of relationships between morphological and behavioural feeding adaptations across species
Hepatitis B testing, treatment, and virologic suppression in HIV-infected patients in Cameroon (ANRS 12288 EVOLCAM)
No full textBackgroundHepatitis B is a major concern in Africa, especially in HIV-infected patients. Unfortunately, access to hepatitis B virus (HBV) testing and adequate treatment remains a challenge in the continent. We investigated HBV testing, treatment, and virologic suppression in HIV-infected patients followed up as part of Cameroon's national antiretroviral programme.MethodsA cross-sectional survey was performed in adult patients receiving antiretroviral therapy (ART) in 19 hospitals in the Centre and Littoral regions in Cameroon. The proportions of patients tested for hepatitis B surface antigen (HBsAg) prior to the study were compared among all study hospitals using the Chi-square test. The association of individual and hospital-related characteristics with HBV testing and virologic suppression was assessed using multilevel logistic regression models.ResultsOf 1706 patients (women 74%, median age 42years, median time on ART 3.9years), 302 (17.7%) had been tested for HBsAg prior to the study. The proportion of HBV-tested patients ranged from 0.8 to 72.5% according to the individual hospital (p <0.001). HBV testing was lower in women (adjusted odds ratio [aOR] 0.64, 95% confidence interval [CI] 0.46-0.89, p =0.010) and higher in patients who initiated ART in 2010 or later (aOR 1.66, 95% CI 1.23-2.27, p <0.001). Of 159 HBsAg-positive patients at the time of the study (9.3%), only 97 (61.0%) received Tenofovir + Lamivudine (or Emtricitabine). Of 157 coinfected patients, 114 (72.6%) had a HBV viral load <10IU/mL. HBV suppression was higher in patients with a HIV viral load <300 copies/mL (aOR 3.46, 95% CI 1.48-8.09, p= 0.004) and lower in patients with increased ALT level (aOR 0.86 per 10IU/mL increase, 95% CI 0.75-0.97, p =0.019).ConclusionsA substantial proportion of HIV/HBV coinfected patients were at higher risk of liver disease progression. Improving the management of HBV infection in the routine healthcare setting in Africa is urgently required in order to achieve the 2030 elimination targets. Micro-elimination of HBV infection in people living with HIV could be an easier and cost-effective component than more widely scaling up HBV policies
Evaluation of backscattering models and support vector machine for the retrieval of bare soil moisture from Sentinel-1 Data
No full textThe main objective of this work was to retrieve surface soil moisture (SSM) by using scattering models and a support vector machine (SVM) technique driven by backscattering coefficients obtained from Sentinel-1 satellite images acquired over bare agricultural soil in the Tensfit basin of Morocco. Two backscattering models were selected in this study due to their wide use in inversion procedures: the theoretical integral equation model (IEM) and the semi-empirical model (Oh). To this end, the sensitivity of the SAR backscattering coefficients at VV (sigma vv degrees) and VH (sigma vh degrees) polarizations to in situ soil moisture data were analyzed first. As expected, the results showed that over bare soil the sigma vv degrees was well correlated with SSM compared to the sigma vh degrees, which showed more dispersion with correlation coefficients values (r) of about 0.84 and 0.61 for the VV and VH polarizations, respectively. Afterwards, these values of sigma vv degrees were compared to those simulated by the backscatter models. It was found that IEM driven by the measured length correlation L slightly underestimated SAR backscatter coefficients compared to the Oh model with a bias of about -0.7 dB and -1.2 dB and a root mean square (RMSE) of about 1.1 dB and 1.5 dB for Oh and IEM models, respectively. However, the use of an optimal value of L significantly improved the bias of IEM, which became near to zero, and the RMSE decreased to 0.9 dB. Then, a classical inversion approach of sigma vv degrees observations based on backscattering model is compared to a data driven retrieval technic (SVM). By comparing the retrieved soil moisture against ground truth measurements, it was found that results of SVM were very encouraging and were close to those obtained by IEM model. The bias and RMSE were about 0.28 vol.% and 2.77 vol.% and -0.13 vol.% and 2.71 vol.% for SVM and IEM, respectively. However, by taking into account the difficultly of obtaining roughness parameter at large scale, it was concluded that SVM is still a useful tool to retrieve soil moisture, and therefore, can be fairly used to generate maps at such scales
Identification and synthesis of putative pheromone components of the threatened salt marsh bagworm moth, Whittleia retiella (Lepidoptera : Psychidae)
No full textWhittleia retiella (Newman, 1847) is a threatened salt marsh species of the bagworm moth family Psychidae. For its preservation it is necessary to develop efficient tools to survey its distribution and habitat requirements in order to use appropriate conservation methods. Such tools may be pheromone-based monitoring systems, which have documented efficacy in establishing the occurrence of cryptic insect species in nature. By using gas chromatography combined with electroantennographic detection (GC-EAD), we found two compounds in female W. retiella headspace samples and whole-body extracts that elicited electrophysiological activity in male antennae. Gas chromatograpy coupled with mass spectrometry (GC-MS) operating in electron impact (EI) mode and comparison of the analytical data with those of synthetic reference compounds showed the chemical structures of these putative pheromone components to be (1S)-1-methylpropyl (5Z)-dec-5-enoate and 1-methylethyl (5Z)-dec-5-enoate. Field assays using baits loaded with synthetic compounds revealed that conspecific males were attracted to (1S)-1-methylpropyl (5Z)-dec-5-enoate alone or in combination with 1-methylethyl (5Z)-dec-5-enoate, whereas 1-methylethyl (5Z)-dec-5-enoate neither attracted nor repelled males in the field assays when tested alone. This study shows the potential of using (1S)-1-methylpropyl (5Z)-dec-5-enoate for monitoring W. retiella to gather more detailed information about the geographic distribution and habitat needs of this rare moth
The hyperdominant tropical tree Eschweilera coriacea (Lecythidaceae) shows higher genetic heterogeneity than sympatric Eschweilera species in French Guiana
No full textBackground and aims - The evolutionary history of Amazonia's hyperabundant tropical tree species. also known as "hyperdominant" species, remains poorly investigated. We assessed whether the hyperdominant Eschweilera coriacea (DC.) S.A.Mori (Lecythidaceae) represents a single genetically cohesive species, and how its genetic constitution relates to other species from the same Glade with which it occurs sympatrically in French Guiana. Methods - We sampled 152 individuals in nine forest sites in French Guiana, representing 11 species of the genus Eschweilera all belonging to the Parvifolia Glade, with emphasis on E. coriacea. Samples were genotyped at four simple sequence repeat (SSR) markers. We delimited gene pools, i.e.. genetically coherent putative taxa, using STRUCTURE software and principal component analysis. We compared the genetic assignment of individuals with their morphological species determination and estimated genetic diversity and differentiation for gene pools and species. We also estimated genome size using flow cytometry. Key results - SSR profiles commonly displayed up to four alleles per genotype, suggesting that the investigated Eschweilera species bear a paleopolyploid signature. Flow cytometty suggested that the studied species are diploid with haploid genome sizes of 871-1046 Mbp. We detected five gene pools and observed a good correspondence between morphological and genetic delimitation for Eschweilera sagotiana Miers and the undescribed morphospecies E. sp. 3 (which resembles E. grandiflora (Aubl.) Sandwith), and to a lesser extent for E. decolorans Sandwith and E. micrantha (O.Berg) Miers. Eschweilera coriacea was the most genetically diverse species and included individuals assigned to each gene pool. Conclusions - We found no conclusive evidence for cryptic species within E. coriacea in French Guiana. SSRs detected fewer gene pools than expected based on morphology in the Parvifolia Glade but discriminated evolutionary relationships better than available plastid markers. A positive trend between demographic abundance of species and allelic richness illustrates that hyperdominants may have a high evolutionary potential. This hypothesis can be tested using more powerful genomic data in combination with tree phenotypic trait variation and characterization of niche breadth, to enhance our understanding of the causes of hyperdominance in Amazonian trees
Control of fault weakening on the structural styles of underthrusting-dominated non-cohesive accretionary wedges
No full textUnderthrusting is a typical process at compressive margins responsible for nappe stacking and sediment subduction. In nature, underthrusting is often associated with weak basal faults, although static mechanical analysis (critical taper theory) suggests that weak basal faults promote accretion while strong basal faults promote underthrusting. We perform mathematical analyses and numerical simulations to determine whether permanent fault weakening promotes or inhibits underthrusting. We investigate the control of permanent fault weakening on the dynamics of a strong-based ((1 -lambda(b)*)mu(b) approximate to (1 -lambda*)mu) non-cohesive wedge (mu and mu(b) are internal and basal friction, respectively). We control the wedge material strength by a spatially constant fluid overpressure factor (lambda*), and fault strength by a plastic strain weakening factor (chi). First, we use the critical taper theory to determine a mechanical mode diagram that predicts structural styles. Then, we perform numerical simulations of accretionary wedge formation to establish their dynamical structural characteristics. We determine a continuum of structural styles between three end-members which correspond to the theoretical mechanical mode transitions. Style 1 is characterized by thin tectonic slices and little to no underthrusting. Style 2 shows thick slices, nappe stacking, and shallow gravity-driven tectonics. Style 3 displays the complete underthrusting of the incoming sediments, that are exhumed when they reach the backstop. We conclude that in the condition of an initially strong wedge base, permanent fault weakening promotes underthrusting. Thus, this contribution enlightens the control of the dynamic evolution of material properties on the formation of subduction channels, slope instabilities, and antiformal nappe stacks
Coalition formation with dynamically changing externalities
No full textWe consider multiple self-interested bounded-rational agents each of which has a goal it needs to achieve. Goals are achievable by executing a set of interdependent tasks. Some tasks exhibit time dependencies and may require sequential execution. For each agent, there may be several alternative sets of tasks that can achieve the goal. Execution of alternatives, may be more beneficial when done by a group of agents and not by a single agent. To jointly achieve goals, agents may form interdependent coalitions. Such coalition formation is computationally intractable. We nevertheless seek a practical solution that is not necessarily optimal yet acceptable by the agents. A solution where agents examine only coalitions in which they are members is inapplicable, as externalities are a major factor given task interdependencies. In this paper we study this coalition formation problem. We describe the problem and introduce a novel Multi-lateral Negotiation Protocol (MNP) that solves it by forming interdependent coalitions. We allow agents to heuristically make gradual concessions, revise their proposals and converge on specific alternatives, and nevertheless increase their expected gains