IMF programs and tax effort What role for institutions in Africa?

When compared to other developing countries, most Sub-Saharan African countries are characterized by a disappointing level of development. Among the factors explaining this poor performance, the inadequate supply of public goods is often advocated. This inadequate supply is due either to poor efficiency of public expenditure, or to an insufficient tax effort. This paper is focused on this last factor. One of the reasons for the low level of public revenues could be the weak impact of the IMF programs on the tax effort. In the agreements that developing countries reach with the IMF, they commit to reduce their macro-economic imbalances, notably fiscal deficit, to a sustainable level. The measures necessary to achieve the overall budgetary objectives apply mainly to public expenditures as they are easy to reduce in the short term. However, the hypothesis of a positive effect of IMF programs must be considered: one objective of the African governments could be to maintain public expenditures at their previous level. To this end, African governments could choose to mobilize additional public revenues. Thus, most of IMF programs promote tax reforms leading to a more effective policy of public revenue mobilization. This last scenario of an increase of the level of public revenue is corroborated by the econometric analysis. The level of public revenue depends, among other factors, on the quality of institutions. However, the institutional quality of custom and tax administrations is weaker in Africa than elsewhere. This poor quality reduces the efficiency of IMF programs which may have a lower impact on the level of public revenue in African countries. These results point up two main lessons for the IMF (and more generally for lenders) and for recipient countries: 1) The role of technical assistance associated with the IMF programs is crucial, since it enables capacity reinforcement of the technical administrations in charge of the definition and implementation of the reform; 2) The technical assistance for tax and custom administrations must be strengthened for those countries which initially have a poor quality of bureaucracy.

IMF programs and tax effort What role for institutions in Africa?

When compared to other developing countries, most Sub-Saharan African countries are characterized by a disappointing level of development. Among the factors explaining this poor performance, the inadequate supply of public goods is often advocated. This inadequate supply is due either to poor efficiency of public expenditure, or to an insufficient tax effort. This paper is focused on this last factor. One of the reasons for the low level of public revenues could be the weak impact of the IMF programs on the tax effort. In the agreements that developing countries reach with the IMF, they commit to reduce their macro-economic imbalances, notably fiscal deficit, to a sustainable level. The measures necessary to achieve the overall budgetary objectives apply mainly to public expenditures as they are easy to reduce in the short term. However, the hypothesis of a positive effect of IMF programs must be considered: one objective of the African governments could be to maintain public expenditures at their previous level. To this end, African governments could choose to mobilize additional public revenues. Thus, most of IMF programs promote tax reforms leading to a more effective policy of public revenue mobilization. This last scenario of an increase of the level of public revenue is corroborated by the econometric analysis. The level of public revenue depends, among other factors, on the quality of institutions. However, the institutional quality of custom and tax administrations is weaker in Africa than elsewhere. This poor quality reduces the efficiency of IMF programs which may have a lower impact on the level of public revenue in African countries. These results point up two main lessons for the IMF (and more generally for lenders) and for recipient countries: 1) The role of technical assistance associated with the IMF programs is crucial, since it enables capacity reinforcement of the technical administrations in charge of the definition and implementation of the reform; 2) The technical assistance for tax and custom administrations must be strengthened for those countries which initially have a poor quality of bureaucracy.cerdi

Formic Acid Synthesis in a Water–Mineral System: Major Role of the Interface

Mineral surfaces are known for their catalytic properties, as they lower kinetic bar- riers to reactions, and modify chemical equilibria. Using ab-initio molecular dynamics and enhanced sampling methods we predict that the MgO(001)/water interface ther- modynamically favours the formation of formic acid from carbon monoxide and water. This occurs despite the lack of direct participation from the surface atoms, the reac- tion taking place beyond the first adsorbed layer. Furthermore, the application of an external electric field on the reaction in bulk water shows a similar effect. We propose that formic acid may be stabilised by the surface electric field, by direct comparison with the equilibrium in bulk water with and without an external electric field applied, and at the MgO(001)/water interface

IMF programs and tax effort What role for institutions in Africa?

When compared to other developing countries, most Sub-Saharan African countries are characterized by a disappointing level of development. Among the factors explaining this poor performance, the inadequate supply of public goods is often advocated. This inadequate supply is due either to poor efficiency of public expenditure, or to an insufficient tax effort. This paper is focused on this last factor. One of the reasons for the low level of public revenues could be the weak impact of the IMF programs on the tax effort. In the agreements that developing countries reach with the IMF, they commit to reduce their macro-economic imbalances, notably fiscal deficit, to a sustainable level. The measures necessary to achieve the overall budgetary objectives apply mainly to public expenditures as they are easy to reduce in the short term. However, the hypothesis of a positive effect of IMF programs must be considered: one objective of the African governments could be to maintain public expenditures at their previous level. To this end, African governments could choose to mobilize additional public revenues. Thus, most of IMF programs promote tax reforms leading to a more effective policy of public revenue mobilization. This last scenario of an increase of the level of public revenue is corroborated by the econometric analysis. The level of public revenue depends, among other factors, on the quality of institutions. However, the institutional quality of custom and tax administrations is weaker in Africa than elsewhere. This poor quality reduces the efficiency of IMF programs which may have a lower impact on the level of public revenue in African countries. These results point up two main lessons for the IMF (and more generally for lenders) and for recipient countries: 1) The role of technical assistance associated with the IMF programs is crucial, since it enables capacity reinforcement of the technical administrations in charge of the definition and implementation of the reform; 2) The technical assistance for tax and custom administrations must be strengthened for those countries which initially have a poor quality of bureaucracy

Static Segmentations in Dynamic PET Images: The need for a new method

The Task Group 211 report of the American Association of Physicists in Medicine (AAPM) reviewed static segmentation techniques in nuclear positronemission tomography (PET) imaging used in nuclear medicine. These methods, when applied to a dynamic image, such as the ones obtained in pharmacokinetic analyses, fail to take into account the dynamic nature of the acquisitions. In this article, the leading hypothesis was that a static segmentation was not adequate in even the simplest dynamic PET images. To put this idea forward, a simple dynamic PET phantom was devised. Many dynamic acquisitions were obtained using FDG. To analyze them, different static segmentations were performed on each timeframe. These were followed by quantitative analyses to determine whether the segmentations were consistant between various timeframes of reference. The quantitative analytical tools used were the S{\o}rensen-Dice coefficients, the overlapping of the time-activity curves (TACs), and the pharmacokinetic parameters extracted from the images using the Dynesty Python package. In order to perform some of the analyses, an uncertainty had to be added to the TACs themselves: to do so, the individual segmentations were spatially displaced to estimate the sensibility of the TAC to the underlying segmentation. Using these analytical tools, we propose that static segmentations are not sufficient tools for segmenting dynamic images in a nuclear medicine context. The specific case of pharmacokinetic modelling is used to exemplify this idea. Further work could include a method of estimating uncertainties on segmentations or a novel method for dynamic segmentations in dynamic PET images.Comment: 15 pages, 5 figure

Financement externe et politique budgétaire : le rôle du Stabex

In the literature, when the price of primary products is booming, developing countries are generally facing an increase in the availability of foreign financing. The STABEX payments should occur after a shortfall export earnings, and as a consequence when government revenues are falling. We show that these payments, when they are made during periods of low real government revenues, allow for additional public expenditures. On the contrary, when payments are made during periods of high real revenues, they substitute for other ways of financing and have no expansionary effect. This is a strong argument in favour of STABEX.

Le modèle confluent de l'agression sexuelle appliqué à quatre paramètres de la carrière criminelle sexuelle

Ce mémoire consiste en une reproduction et une extension du Modèle Confluent de l’Agression Sexuelle (MCAS) de Neil Malamuth. Le MCAS est un des seuls modèles développementaux de l’agression sexuelle d’hommes sur des femmes adultes à avoir été validé empiriquement. Dans ce modèle, deux trajectoires (la promiscuité sexuelle et la masculinité hostile) convergent et mènent à l’agression sexuelle. Pour la première fois, ce modèle est appliqué séparément à quatre paramètres de la carrière criminelle sexuelle (gravité, fréquence, précocité, spécialisation) au sein d’un échantillon d’agresseurs sexuels de femmes adultes judiciarisés (n=180). Les quatre modèles qui en résultent s’ajustent bien aux données. Tous les liens postulés dans le MCAS sont validés dans ce mémoire, à une exception. En effet, contrairement aux résultats obtenus par Malamuth, une seule des deux trajectoires du modèle présente un lien significatif avec chacun des paramètres de la carrière criminelle sexuelle à l’étude. La trajectoire de la promiscuité sexuelle est liée à la précocité et à la non-spécialisation (lien négatif avec la spécialisation) alors que la trajectoire de la masculinité hostile est associée à la gravité et à la fréquence. Ces résultats sont congruents avec une approche typologique des agresseurs sexuels de femmes adultes. Chacune des deux trajectoires du MCAS englobe des caractéristiques spécifiques à certains types de violeurs (opportunistes, colériques, sadiques) qui, pour leur part, se distinguent quant aux paramètres de leur carrière criminelle sexuelle.The purpose of this thesis is to replicate and extend Malamuth’s Confluence Model of Sexual Aggression (CMSA). The CMSA is one of the few empirically validated developmental models of men’s sexual aggression against women. In this model, sexual aggression is resulting from the convergence of two paths (sexual promiscuity and hostile masculinity). For the first time, in this thesis, the CMSA is applied to four parameters of the sexual criminal career (seriousness, frequency, age of onset, specialization) within a sample of convicted rapists (n=180). Each of the four resulting models yielded a good fit of the data. All but one of the relationships hypothesized in the CMSA were replicated in this thesis. Indeed, our results suggest that only one of the CMSA’s paths is related to each of the sexual criminal career parameters tested in this thesis. The sexual promiscuity path is related to age of onset and non-specialization (sexual promiscuity being negatively related to specialization) while the hostile masculinity path is related to seriousness and frequency. Our results are congruent with a typological approach of rapists. Each of the two CMSA’s paths is operationalized using some specific characteristics which are known to be linked to certain types of rapists (opportunistic, angry, sadistic types). In turn, those types of rapists present distinctive relationships to the sexual criminal career parameters investigated in this thesis

An integer L-shaped algorithm for the Dial-a-Ride Problem with stochastic customer delays

AbstractThis paper considers a single-vehicle Dial-a-Ride Problem in which customers may experience stochastic delays at their pickup locations. If a customer is absent when the vehicle serves the pickup location, the request is fulfilled by an alternative service (e.g., a taxi) whose cost is added to the total cost of the tour. In this case, the vehicle skips the corresponding delivery location, which yields a reduction in the total tour cost. The aim of the problem is to determine an a priori Hamiltonian tour minimizing the expected cost of the solution. This problem is solved by means of an integer L-shaped algorithm. Computational experiments show that the algorithm yields optimal solutions on several instances within reasonable CPU times. It is also shown that the actual cost of an optimal solution obtained with this algorithm can be significantly smaller than that of an optimal solution obtained with a deterministic formulation

Morpho-statistical description of networks through graph modelling and Bayesian inference

Collaborative graphs are relevant sources of information to understand behavioural tendencies of groups of individuals. Exponential Random Graph Models (ERGMs) are commonly used to analyze such social processes including dependencies between members of the group. Our approach considers a modified version of ERGMs, modeling the problem as an edge labelling one. The main difficulty is inference since the normalising constant involved in classical Markov Chain Monte Carlo (MCMC) approaches is not available in an analytic closed form. The main contribution is to use the recent ABC Shadow algorithm. This algorithm is built to sample from posterior distributions while avoiding the previously mentioned drawback. The proposed method is illustrated on real data sets provided by the Hal platform and provides new insights on self-organised collaborations among researchers

A peculiar galaxy appears at redshift 11: properties of a moderate redshift interloper

Laporte et al. (2011) reported a very high redshift galaxy candidate: a lensed J-band dropout (A2667-J1). J1 has a photometric redshift of z=9.6-12, the probability density function for which permits no low or intermediate z solution. We here report new spectroscopic observations of this galaxy with VLT/XShooter, which show clear [OIII]5007AA, Ly-alpha, H-alpha, and H-beta emission and place the galaxy firmly at z=2.082. The oxygen lines contribute only ~25% to the H-band flux, and do not significantly affect the dropout selection of J1. After correcting the broadband fluxes for line emission, we identify two roughly equally plausible natures for A2667-J1: either it is young heavily reddened starburst, or a maximally old system with a very pronounced 4000AA break, upon which a minor secondary burst of star formation is superimposed. Fits show that to make a 3 sigma detection of this object in the B-band (V-band), imaging of depth AB=30.2 (29.5) would be required - despite the relatively bright NIR magnitude, we would need optical data of equivalent depth to the Hubble Ultra Deep Field to rule out the mid-z solution on purely photometric grounds. Assuming that this stellar population can be scaled to the NIR magnitudes of recent HST/WFC3 IR-selected galaxies, we conclude that infeasibly deep optical data AB~32 would be required for the same level of security. There is a population of galaxies at z~2 with continuum colours alone that mimic those of our z=7-12 candidates.Comment: Accepted by Monthly Notices. 5 pages, 2 figure