Informal versus formal : a panel data analysis of earnings gaps in Madagascar

In spite of its predominant economic weight in developing countries, little is known about informal sector income dynamics vis-à-vis the formal sector. Some works have been done in this field using household surveys, but they only consider some emerging Latin American countries (Argentina, Brazil, Colombia and Mexico; Gong et al., 2004; Perry et al., 2007; Bargain and Kwenda, 2011) and more recently South Africa, Ghana and Tanzania for Africa (Falco et al., 2010) and Vietnam for Asia (Nguyen et al., 2011). As a matter of consequence, there is still no way to generalize the (diverging) results to very poor part of the developing world. Taking advantage of the rich 1-2-3 Surveys dataset in Madagascar, in particular its four waves panel data (2000, 2001, 2003 and 2004), we assess the magnitude of various formal/informal sector earnings gaps while addressing heterogeneity issues at three different levels: the worker, the job (wage employment vs. selfemployment) and the earnings distribution. The questions asked are the following: Is there an informal sector job earnings penalty? Do some informal sector jobs provide pecuniary premiums? Which ones? Do possible gaps vary along the earnings distribution? Standard earnings equations are estimated at the mean and at various conditional quantiles of the earnings distribution. In particular, we estimate fixed effects quantile regressions to control for unobserved individual characteristics, focusing particularly on heterogeneity within both the formal and informal sector categories. Our results suggest that the informal sector earnings gap highly depends on the workers’ job status and on their relative position in the earnings distribution. Penalties may in some cases turn into premiums. By comparing our results with studies in other developing countries, we draw conclusions highlighting the Madagascar’s labour market specificity.no

Remote sensing and urban malaria: radar Envisat contribution for the determination of potential Anopheles breeding site in Antananarivo (Madagascar)

International audienceMost studies of anopheline mosquito larval ecology have been done in rural settings. However, latest data based on two cross-sectional surveys in Antananarivo, the capitol of Madagascar, shown low rate of malaria cases among febrile episodes but autochthonous malaria cases exist. Anopheles funestus constitutes the main vector of malaria in the highlands of Madagascar. This paper described the determination of their potential breeding site using remotely sensed data. A supervised classification by the classical method of maximum likelihood was used for enhanced thematic mapper image of Landsat 7. Overall accuracy of the classification was 86% and kappa index was 0.835. Determination of landscape change by subtraction of images acquired on January and July was carried out for the Advanced Synthetic Aperture Image Precision images of Envisat. Increased backscatter coefficient between the two periods made possible to raise ambiguity between rice fields and other vegetation. That may improve the determination of potential anopheles breeding sites

Strain rate effect on the mechanical behavior of the anterior cruciate ligament-bone complex

Traction tests were performed on the bovine anterior cruciate ligament-bone complex at seven strain rates (0.1, 1, 5, 10, 20, 30, 40%/s). Corresponding stress-strain curves showed that, for a given strain level, the stress increased with the augmentation of the strain rate. This phenomenon was important since the stress increased by a factor of three between the tests performed at the lowest and highest strain rates. The influence of the strain rate was quantified with a new variable called the "supplemental stress". This variable represented the percentage of total stress due to the effect of strain rate. It was observed that at a strain rate of 40%/s, more than 70% of the stress in the ligament was due to the strain rate effect. In fact, the strain rate strongly affected the toe region, but did not influence the linear part of the stress-strain curves. The use of the linear tangent moduli was then not adequate to describe the strain rate effect in the anterior cruciate ligament-bone complex. This study showed that the "supplemental stress" was a synthetic and convenient variable to quantify the effect of the strain rate on the entire stress-strain curves. This quantification is especially important when comparing the mechanical behavior between anterior cruciate ligament and tissues used as ligament graft. (C) 1999 IPEM. Published by Elsevier Science Ltd. All rights reserved

The fixation of the cemented femoral component - Effects of stem stiffness, cement thickness and roughness of the cement-bone surface

After cemented total hip arthroplasty (THA) there may be failure at either the cement-stem or the cement-bone interface. This results from the occurrence of abnormally high shear and compressive stresses within the cement and excessive relative micromovement. We therefore evaluated micromovement and stress at the cement-bone and cement-stem interfaces for a titanium and a chromium-cobalt stem. The behaviour of both implants was similar and no substantial differences were found in the size and distribution of micromovement on either interface with respect to the stiffness of the stem. Micromovement was minimal with a cement mantle 3 to 4 mm thick but then increased with greater thickness of the cement. Abnormally high micromovement occurred when the cement was thinner than 2 mm and the stem was made of titanium. The relative decrease in surface roughness augmented slipping but decreased debonding at the cement-bone interface. Shear stress at this site did not vary significantly for the different coefficients of cement-bone friction while compressive and hoop stresses within the cement increased slightly

Viscoelastic constitutive law in large deformations: application to human knee ligaments and tendons

Traction tests on soft tissues show that the shape of the stress strain curves depends on the strain rate at which the tests are performed. Many of the constitutive models that have been proposed fail to properly consider the effect of the strain rate when large deformations are encountered. In the present study, a framework based on elastic and viscous potentials is developed. The resulting constitutive law is valid for large deformations and satisfies the principles of thermodynamics. Three parameters -- two for the elasticity and one for the viscosity -- were enough to precisely fit the non-linear stress strain curves obtained at different strain rates with human cruciate ligaments and patellar tendons. The identification results then in a realistic, three-dimensional viscoelastic constitutive law. The developed constitutive law can be used regardless of the strain or rotation values. It can be incorporated into a finite element program to model the viscoelastic behavior of ligaments and tendons under dynamic situations

Detraining effects on the mechanical properties and morphology of rat tibiae

To study bone adaptation to detraining in growing rats, nine weeks-old immature female Wistar rats (n=110) were subjected to treadmill running programs (30 or 60 minutes-a-day) for up to 15 weeks, followed by unrestricted cage activities for the subsequent 15 weeks. The results revealed that (1) the cross-sectional area and mechanical properties of the midshaft bone significantly increased in response to running exercise, (2) its structural properties remained unchanged after the cessation of exercise, whereas the material properties returned to control level at a relatively early stage, (3) in the metaphysis, cortical bone area remained unchanged but trabecular bone area decreased in response to running exercise, (4) both areas slightly increased after the cessation of exercise, and (5) the changes in the mechanical properties and morphology of bone depended upon the repetition number and/or the duration of exercise, and were larger with longer duration of exercise

Building an African Leptospirosis Network

Although leptospirosis is a disease of global importance, local context is crucial to formulating effective intervention strategies. Factors including reservoir host species, pathogen type, environmental, and social settings generate context-specific epidemiologies. Diverse climatic zones, agricultural systems, urbanization patterns, and cultural practices in Africa are likely to drive considerable variation in leptospirosis epidemiology. There is growing evidence of a substantial burden of human leptospirosis in Africa that is difficult to quantify in part due to lack of surveillance and clinical awareness of leptospirosis. Leptospirosis is therefore rarely considered as a differential diagnosis for acute febrile illness, and there is little access to diagnostic services for leptospirosis on the continent. In 2016, a virtual network was founded focussing on improving awareness and understanding leptospirosis in Africa. We currently have 40 members from academia, clinical practice, government and non-governmental agencies and others. Current members are based predominantly in institutions outside the continent but increasingly colleagues based in public health, laboratories, veterinary, and academic institutions within Africa are joining. We will share our experiences of developing this network, and our plans for capacity building through identifying and addressing knowledge gaps in our understanding of leptospirosis in Africa

Seroprevalence of malaria in inhabitants of the urban zone of Antananarivo, Madagascar

BACKGROUND: Antananarivo, the capital of Madagascar, is located at an altitude of over 1,200 m. The environment at this altitude is not particularly favourable to malaria transmission, but malaria nonetheless remains a major public health problem. The aim of this study was to evaluate exposure to malaria in the urban population of Antananarivo, by measuring the specific seroprevalence of Plasmodium falciparum. METHODS: Serological studies specific for P. falciparum were carried out with an indirect fluorescent antibody test (IFAT). In a representative population of Antananarivo, 1,059 healthy volunteers were interviewed and serum samples were taken. RESULTS: The seroprevalence of IgG+IgA+IgM was 56.1% and that of IgM was 5.9%. The major risk factor associated with a positive IgG+IgA+IgM IFAT was travel outside Antananarivo, whether in the central highlands or on the coast. The abundance of rice fields in certain urban districts was not associated with a higher seroprevalence. CONCLUSION: Malaria transmission levels are low in Antananarivo, but seroprevalence is high. Humans come into contact with the parasite primarily when travelling outside the city. Further studies are required to identify indigenous risk factors and intra-city variations more clearly

Mapping malaria seasonality in Madagascar using health facility data.

BACKGROUND: Many malaria-endemic areas experience seasonal fluctuations in case incidence as Anopheles mosquito and Plasmodium parasite life cycles respond to changing environmental conditions. Identifying location-specific seasonality characteristics is useful for planning interventions. While most existing maps of malaria seasonality use fixed thresholds of rainfall, temperature, and/or vegetation indices to identify suitable transmission months, we construct a statistical modelling framework for characterising the seasonal patterns derived directly from monthly health facility data. METHODS: With data from 2669 of the 3247 health facilities in Madagascar, a spatiotemporal regression model was used to estimate seasonal patterns across the island. In the absence of catchment population estimates or the ability to aggregate to the district level, this focused on the monthly proportions of total annual cases by health facility level. The model was informed by dynamic environmental covariates known to directly influence seasonal malaria trends. To identify operationally relevant characteristics such as the transmission start months and associated uncertainty measures, an algorithm was developed and applied to model realisations. A seasonality index was used to incorporate burden information from household prevalence surveys and summarise 'how seasonal' locations are relative to their surroundings. RESULTS: Positive associations were detected between monthly case proportions and temporally lagged covariates of rainfall and temperature suitability. Consistent with the existing literature, model estimates indicate that while most parts of Madagascar experience peaks in malaria transmission near March-April, the eastern coast experiences an earlier peak around February. Transmission was estimated to start in southeast districts before southwest districts, suggesting that indoor residual spraying should be completed in the same order. In regions where the data suggested conflicting seasonal signals or two transmission seasons, estimates of seasonal features had larger deviations and therefore less certainty. CONCLUSIONS: Monthly health facility data can be used to establish seasonal patterns in malaria burden and augment the information provided by household prevalence surveys. The proposed modelling framework allows for evidence-based and cohesive inferences on location-specific seasonal characteristics. As health surveillance systems continue to improve, it is hoped that more of such data will be available to improve our understanding and planning of intervention strategies