Renminbi Equilibrium Exchange Rate: an Agnostic View. Kurs równowagi dla waluty chinskiej: zdanie odrebne.

The alleged undervaluation of the renminbi has been the subject of intensive academic research over the past few years. Using equilibrium exchange rate models many authors have concluded that the renminbi is undervalued by 15 to 30% against the US dollar. Yet China has been experiencing strong economic growth for a decade and does not seem to suffer from the supposed misalignment of its exchange rate, with low inflation rate and current account surpluses. The estimations assume that the economy is at full-employment, a strong hypothesis for China, where unemployment amounts to 150 million people. This article claims that a low exchange rate is suited for the objectives of Chinese economic policy. The exchange rate can be undervalued according to traditional models and in equilibrium compared to the government’s policy objectives as shown by a theoretical model.equilibrium exchange rate;developing country exchange rate;China economic strategy;kurs równowagi;kurs walutowy kraju rozwijającego się;chińska strategia gospodarcza;

La valeur du yuan:Les paradoxes du taux de change d’équilibre

La sous-évaluation de la monnaie chinoise vis-à-vis du dollar est souvent dénoncée comme l’une des causes des déséquilibres mondiaux. Les autorités américaines soutiennent que la Chine manipule son taux de change tandis que la majorité des travaux empiriques estiment que le yuan est sous-évalué de 15 à 30 %. Cet article montre que les modèles de taux de change d’équilibre généralement utilisés ne sont pas pertinents pour une économie en développement telle que l’économie chinoise. La Chine souffre d’un sous-emploi massif ; un taux de change sous-évalué au regard des critères traditionnels lui permet d’impulser la croissance vigoureuse nécessaire pour résorber son chômage. Plus généralement, le taux de change optimal d’un pays émergent ne peut être défini que relativement à une stratégie de croissance : plus le pays désire une croissance vigoureuse, plus il est prêt à faire un effort d’épargne, plus il doit pratiquer un taux de change faible. La première partie de l’article décrit les points saillants de la croissance chinoise depuis 1994, où la Chine est passée en change fixe avec le dollar : croissance élevée mais sous-emploi massif, faible inflation, accumulation massive de réserves, forts taux d’épargne et d’investissement. La deuxième partie présente et critique les évaluations du taux de change d’équilibre du yuan selon différentes méthodes. La troisième développe une maquette où le taux de change d’un pays en développement est volontairement fixé à un bas niveau pour permettre une croissance vigoureuse, de sorte que sous-évalué du point de vue des critères usuels, il est optimal du point de vue de la stratégie de croissance ; enfin, la quatrième partie montre la difficulté du choix d’un régime de change pour la Chine

The Renminbi Equilibrium Exchange Rate: an agnostic view

The supposed undervaluation of the renminbi has been the subject of intensive academic research over the past few years. Using equilibrium exchange rate models (Purchasing Power Parity, BEER and FEER), many authors have concluded that the renminbi is undervalued by 15 to 30% against the dollar. This article shows that the common view is not that obvious. The models used in the estimation (BEER or FEER) assume that the economy is at full-employment, a strong hypothesis for developing economies such as China, whose unemployed amount to 150 million people. On the contrary, we show that China is facing massive unemployment and if investment depends on expected potential demand (from domestic consumption and foreign demand), then an undervalued exchange rate (by traditional standards) is suited for its policy objectives. Therefore the exchange rate can be analyzed as a policy tool used by the Chinese authorities to pursue their objectives. The exchange rate can be undervalued by traditional standards and in equilibrium compared to the government’s policy objectives. This article shows that equilibrium exchange rate theories are not suited for developing countries and therefore the concept of equilibrium exchange rate is highly questionable. The final section analyzes the adoption of a managed float regime by the Popular Bank of China and discusses the delicate issue of the best exchange rate regime for China

valeur du yuan. Les paradoxes du taux de change d'équilibre.

La sous-évaluation de la monnaie chinoise vis-à-vis du dollar est souvent dénoncée comme l’une des causes des déséquilibres mondiaux. Les autorités américaines soutiennent que la Chine manipule son taux de change tandis que la majorité des travaux empiriques estiment que le yuan est sous-évalué de 15 à 30 %. Cet article montre que les modèles de taux de change d’équilibre généralement utilisés ne sont pas pertinents pour une économie en développement telle que l’économie chinoise. La Chine souffre d’un sous-emploi massif ; un taux de change sous-évalué au regard des critères traditionnels lui permet d’impulser la croissance vigoureuse nécessaire pour résorber son chômage. Plus généralement, le taux de change optimal d’un pays émergent ne peut être défini que relativement à une stratégie de croissance : plus le pays désire une croissance vigoureuse, plus il est prêt à faire un effort d’épargne, plus il doit pratiquer un taux de change faible. La première partie de l’article décrit les points saillants de la croissance chinoise depuis 1994, où la Chine est passée en change fixe avec le dollar : croissance élevée mais sous-emploi massif, faible inflation, accumulation massive de réserves, forts taux d’épargne et d’investissement. La deuxième partie présente et critique les évaluations du taux de change d’équilibre du yuan selon différentes méthodes. La troisième développe une maquette où le taux de change d’un pays en développement est volontairement fixé à un bas niveau pour permettre une croissance vigoureuse, de sorte que sous-évalué du point de vue des critères usuels, il est optimal du point de vue de la stratégie de croissance ; enfin, la quatrième partie montre la difficulté du choix d’un régime de change pour la Chine.

X-shooter, NACO, and AMBER observations of the LBV Pistol Star \footnote{Based on ESO runs 85.D-0182A, 085.D-0625AC}

We present multi-instruments and multi-wavelengths observations of the famous LBV star Pistol Star. These observations are part of a larger program about early O stars at different metallicities. The Pistol star has been claimed as the most massive star known, with 250 solar masses. We present the preliminary results based on X-Shooter spectra, as well as the observations performed with the VLTI-AMBER and the VLT-NACO adaptive optics. The X-shooter spectrograph allows to obtain simultaneously a spectrum from the UV to the K-band with a resolving power of $\sim$15000. The preliminary results obtained indicate that Pistol Star has similar properties of Eta Car, including shells of matter, but also the binarity. Other objects of the program, here briefly presented, were selected for their particular nature: early O stars with mass discrepancies between stellar evolution models and observations, discrepancies with the wind momentum luminosity relation.Comment: Poster at the 39th LIAC, submitted version of the proceeding

Etiology and risk factors for meningitis during an outbreak in Batié Health District, Burkina Faso, January-March 2016

Introduction: On 16 March 2016, Batié Health District notified the Burkina Faso Ministry of Health Surveillance unit of 12 suspected cases of meningitis. During the same period, Batié´s neighboring districts in Côte d'Ivoire and Ghana were experiencing a meningitis epidemic. We investigated to establish the etiology and risk factors for the disease and to recommend prevention and control measures. Methods: We conducted unmatched case control study. A case was any person living in Batié with fever (temp. ≥ 38.5°C) and any of the following: neck stiffness, neurological disorder, bulging fontanelle, convulsion during January to April 2016 with cerebrospinal fluid (CSF) positive to PCR. Controls were non sick household members, neighbors or friends to the cases. We analyzed the investigation and laboratory records. We included all confirmed cases and two neighborhood controls per case. We used a standard questionnaire to collect data. We analyzed data by Epi info 7 and calculated odds ratio (ORs),adjusted odds ratios (AOR) and 95% confidence interval. We proceeded to univariate, bivariate, multivariate and logistic regression analysis. Results: We interviewed 93 participants including 31 meningitis cases and 62 controls. The median age of cases was 8 years old [2 months-55 years] and 6.5 years old [5 months-51 years] for controls. Streptococcus pneumoniae 16(51.61%), Neisseria meningitidis W 14(45.16%) and Haemophilus influenzae b 1(3.23%) were the identified germs. The independent risk factors identified were travel to meningitis affected areas (Adjusted odd ratio(AOR)=12[2.3-60],p=0.0029); >5 persons sharing bedroom (AOR=5.7[1.5-22],p=0.012) and rhinopharyngitis (AOR=26[1.8-380],p=0.017). Conclusion: Streptococcus pneumoniae and Neisseria meningitidis W caused the outbreak in Batié. The risk factors were overcrowding, travel to affected areas, and rhinopharyngitis. We recommended reactive vaccination against Neisseria meningitidis W, limited travel to affected areas and ventilation of rooms

High-angular resolution observations of the Pistol Star

First results of near-IR adaptive optics (AO)-assisted imaging, interferometry, and spectroscopy of this Luminous Blue Variable (LBV) are presented. They suggest that the Pistol Star is at least double. If the association is physical, it would reinforce questions concerning the importance of multiplicity for the formation and evolution of extremely massive stars.Comment: poster at IAUS27

Luminous blue variables: An imaging perspective on their binarity and near environment

Luminous blue variables (LBVs) are rare massive stars with very high luminosity. They are characterized by strong photo-metric and spectroscopic variability related to transient eruptions. The mechanisms at the origin of these eruptions is not well known. In addition, their formation is still problematic and the presence of a companion could help to explain how they form. Aims. This article presents a study of seven LBVs (about 20% of the known Galactic population), some Wolf-Rayet stars, and massive binaries. We probe the environments that surround these massive stars with near-, mid-, and far-infrared images, investigating potential nebula/shells and the companion stars. Methods. To investigate large spatial scales, we used seeing-limited and near diffraction-limited adaptive optics images to obtain a differential diagnostic on the presence of circumstellar matter and to determine their extent. From those images, we also looked for the presence of binary companions on a wide orbit. Once a companion was detected, its gravitational binding to the central star was tested. Tests include the chance projection probability, the proper motion estimates with multi-epoch observations, flux ratio, and star separations. Results. We find that two out of seven of LBVs may have a wide orbit companion. Most of the LBVs display a large circumstellar envelope or several shells. In particular, HD168625, known for its rings, possesses several shells with possibly a large cold shell at the edge of which the rings are formed. For the first time, we have directly imaged the companion of LBV stars

Multiplicity of northern bright O-type stars with optical long baseline interferometry

The study of the multiplicity of massive stars gives hints on their formation processes and their evolutionary paths, which are still not fully understood. Large separation binaries (>50 milliseconds of arc, mas) can be probed by adaptive-optics-assisted direct imaging and sparse aperture masking, while close binaries can be resolved by photometry and spectroscopy. However, optical long baseline interferometry is mandatory to establish the multiplicity of Galactic massive stars at the separation gap between 1 and 50 mas. In this paper, we aim to demonstrate the capability of the new interferometric instrument MIRC-X, located at the CHARA Array, to study the multiplicity of O-type stars and therefore probe the full range of separation for more than 120 massive stars (H<7.5 mag). We initiated a pilot survey of bright O-type stars (H<6.5mag) observable with MIRC-X. We observed 29 O-type stars, including two systems in average atmospheric conditions around a magnitude of H=7.5 mag. We systematically reduced the obtained data with the public reduction pipeline of the instrument. We analyzed the reduced data using the dedicated python software CANDID to detect companions. Out of these 29 systems, we resolved 19 companions in 17 different systems with angular separations between ~0.5 and 50 mas. This results in a multiplicity fraction fm=17/29=0.59+/-0.09, and an average number of companions fc=19/29=0.66+/-0.13. Those results are in agreement with the results of the SMASH+ survey in the Southern Hemisphere. Thirteen of these companions have been resolved for the first time, including the companion responsible for the nonthermal emission in Cyg OB2-5 A and the confirmation of the candidate companion of HD 47129 suggested by SMASH+. A large survey on more than 120 northern O-type stars (H<7.5) is possible with MIRC-X and will be fruitful.Comment: 15 pages, 9 figures, 5 tables, accepted in A&