362 research outputs found
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
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
Modelling overdispersion with integer-valued moving average processes
A new first-order integer-valued moving average, INMA(1), model based
on the negative binomial thinning operation defined by Risti´c et al. [21] is proposed
and characterized. It is shown that this model has negative binomial (NB) marginal
distribution when the innovations follow a NB distribution and therefore it can be
used in situations where the data present overdispersion. Additionally, this model is
extended to the bivariate context. The Generalized Method of Moments (GMM) is
used to estimate the unknown parameters of the proposed models and the results of
a simulation study that intends to investigate the performance of the method show
that, in general, the estimates are consistent and symmetric. Finally, the proposed
model is fitted to a real dataset and the quality of the adjustment is evaluated.publishe
The Case Against Power Utility and a Suggested Alternative: Resurrecting Exponential Utility
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