Constraints on black-hole charges with the 2017 EHT observations of M87*

Our understanding of strong gravity near supermassive compact objects has recently improved thanks to the measurements made by the Event Horizon Telescope (EHT). We use here the M87* shadow size to infer constraints on the physical charges of a large variety of nonrotating or rotating black holes. For example, we show that the quality of the measurements is already sufficient to rule out that M87* is a highly charged dilaton black hole. Similarly, when considering black holes with two physical and independent charges, we are able to exclude considerable regions of the space of parameters for the doubly-charged dilaton and the Sen black holes

Inference for bivariate integer-valued moving average models based on binomial thinning operation

Time series of (small) counts are common in practice and appear in a wide variety of fields. In the last three decades, several models that explicitly account for the discreteness of the data have been proposed in the literature. However, for multivariate time series of counts several difficulties arise and the literature is not so detailed. This work considers Bivariate INteger-valued Moving Average, BINMA, models based on the binomial thinning operation. The main probabilistic and statistical properties of BINMA models are studied. Two parametric cases are analysed, one with the cross-correlation generated through a Bivariate Poisson innovation process and another with a Bivariate Negative Binomial innovation process. Moreover, parameter estimation is carried out by the Generalized Method of Moments. The performance of the model is illustrated with synthetic data as well as with real datasets.publishe

Arterial oxygen saturation under hypoxic environment of high-altitude associates with routine physical activities of natives

Per cent oxygen saturation of arterial haemoglobin levels (SaO2), a measure of hypoxemia has been analysed in the permanent residents of Ladakh. The population recognized as high-altitude controls (HAC) and high-altitudemonks (HAM), resided at the same altitude of 3600 m but differed in their routines. SaO2 was measured with a Finger-Pulse Oximeter. The HAM had 3.08% higher SaO2 (P<0.001) compared to the HAC, with mean SaO2 of 91.8°6.1% and 89.0°2.6%, respectively. Furthermore, the younger HAM also revealed an elevation of 4.55% SaO2 than the HAC of identical age (P<0.001). The HAM, who are less hypoxemic than their counterparts are physically more active, which may be a selective advantage in the extreme environment of higher altitudes

Rational land and housing bubbles in infinite-horizon economies

URL des Documents de travail : http://ces.univ-paris1.fr/cesdp/cesdp2016.htmlDocuments de travail du Centre d'Economie de la Sorbonne 2016.27 - ISSN : 1955-611XThis paper considers rational land and housing bubbles in an infinite-horizon general equilibrium model. Their demands rest on two different grounds: the land is an input to produce while the house may be consumed. Our work differs from the existing literature in two respects. First, dividends on both these long-lived assets are endogenous and their sequences are computed. Second, we introduce and study different concepts of bubbles, including individual and strong bubbles

Fiscal Policy, Private Investment and Economic Growth: Evidence from G-7 Countries

Measuring the effects of fiscal policy on economic growth is difficult, because fiscal policy variables are influenced by changes in income. This paper uses an unbalanced panel data set for G-7 countries for the period 1965-2000 that includes annual estimates of cyclically adjusted government expenditures, capital outlays, income tax revenues, indirect tax revenues, corporate tax revenues and social security tax revenues, based on definitions developed by OECD revenue statistics. The percentage share of these estimates in GDP is used to investigate the effects of fiscal policy on economic growth, and results are compared with regression results that use 5-year averages of cyclically unadjusted variables. The empirical results from both sets of regressions suggest that only taxes on household income and government expenditures have negative effects on per capita income growth. We consolidate our findings by showing that both government expenditures and income taxes have distortionary effects on private investment